College of Engineering and Petroleum
Chemical Engineering Department
Plant Design (ChE 491)
May /2012
Production of Ethanol from syngas
Group Members:
Khalid al-Sulaili
204215889
Mosleh Mohammed
207217019
Omar Ali
205112892
Yousef bahbahani
207111495
Eid Ali
206113669
Supervised by :
Prof. Mohamed A. Fahim
Eng. Yusuf Ismail Ali
1
Acknowledgements
During the course of senior design project, many individuals have unselfishly contributed their
time and support to help make this project possible. We would like to extend our sincere
gratitude to those who have provided guidance in every step along the way.
First and foremost, we would like to thank after ALLAH, Prof. Mohammed Fahim. You have
been
a great and wonderful mentor throughout this project. Your exceptional insight and technical
knowledge has been much appreciated. Thank you for taking the time to assist us all the way.
Special thanks Eng. Yusuf Ali. Thank you for your dedication and timely, constructive
feedback that made this course an outstanding learning experience. Thank you!
Our deep gratitude to our parents and families for their loving support and patient
they have given us along our path with the project and studies. Without them, we would
not have achieved and accomplished our success today. Thank you for everything.
By Engineers:
Eid Ali
Khalid al-Sulaili
Mosleh Mohammed
Omar Ali
Yousef bahbahani
2
Executive Summary
The main objective of this project was to design a ethanol production plant that produces
600,000,000 lb/yr of ethanol .
The importance of this alcohol can noticed in chemical industries especially nowadays in
blending ethanol with gasoline and trying to make it the fuel of the future. There are different
production methods with wide range of feed stocks. The method used in our plant is ethanol
production from syngas.
There are side products of this method such : acetaldehyde , ethyl acetate and acetic acid.
Five tasks were required to complete the ethanol plant for plant design course, and we were able
to cover those five task in the following five chapters:
The first chapter of this report is the literature survey, in this chapter we discuss the properties
and uses of ethanol in the industry, the chemical and physical properties of raw materials,
history of ethanol production, reactions and thermo dynamics plus kinetics involved in ethanol
production, catalyst used for the ethanol production, the various process routes to manufacture
ethanol .
The second chapter focuses on the UNISIM simulation. A computer simulation of the plant is
described in this chapter; the software used for this simulation is called Hysys. This software
estimates various factors and balances. The process of reaction section, pre distillation section
and
distillation section has been described in detailed; also all of the equipments
have been individually explained in details.
In the third chapter a detailed design calculations of all the major and minor equipments in the
plant has been preformed. Also a specification sheet of each equipment size, construction details
and material of construction is provided.
In the fourth chapter an assessment of the safety features in the plant design is taken, also we will
focus on health hazards that may occur in the plant. We will also touch upon (HAZOP) which is
hazard and operability studies, which is an indicator of the danger level of the plant.
The fifth chapter explains the economic study and project evolution for the selected
petrochemical plant. Also an estimation of capital costs, plant life span, manufacturing costs,
yearly sales revenue market, interest rates, return of Investment in terms of pay back period.
The pay back period was estimated as 3 years. Thus this plant proves to be greatly favorable.
3
Table of Content
Chapter 1: Literature Survey
Introduction…………………………………………………………….…....10
Methods of producing ethanol ………………………………………….11
History...………………………………………………………………….……12
Uses………………………………… …………………………………………13
World production……………………………………………………...........15
Feed stock……………………………………………………………………….18
First Process : ethanol from syngas …………………..…………………….27
Catalyst..........................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,..............28
Products………………………………………………………………………….31
Second process: Fermentation ………………………………………………36
Third Process : Ethylene hydration …………………………………………...43..
Comparison between process .................................................................48
Discussion ………………………………………………………………………...50.
Chapter 2: Hysys simulation and material balance
Hysys simulation program..........................................................................54
Process description........................................................................................60
Process Equipments summary.......................................................................85
Material balance …………………………………………………………………88
Stream information overall plant .............................................................88-89
4
Chapter 3: Equipment Design
Abstract.................................................................................................91
Distillation columns.................................................................................93
Reactor ……………………………………………………………………..128
Separator …………………………………………………………………..141
Absorber ……………………………………………………………………..148
Heat exchangers...................................................................................166
Compressors..........................................................................................194
Chapter 4: Safety and HAZOP
Introduction to safety............................................................................205
Environmental affect...........................................................................208
HAZOP on distillation column……………………………………..........209
NFPA 704 analysis of components ……………………………………….218
Chapter 5 : Economic Cost
Equipment cost ………………………………………………………………224
Utility summary .......................................................................................227
Cost of raw materials and products and waste water treatment.......................228
Payback period .................................................................230
Conclusion......................................................................................................237
References......................................................................................................238
Appendix ……………………………………………239
5
List of Figures:
1-Ethanol world production …………………………………………….……..….16
2-Ethanol world consumption………………………………………………….….16
3-syngas sources………………………………………………………………..……18
4-Gasification Basics…………………………………………………………………23
5-Flowsheet ethanol from syngas……………………………………………..….25
6-Reactor shell and tube……………………………………………………………29
7-Slurry Reactor ………………………………………………………………………30
8-Block flow diagram for fermentation process ……………………………….39
9-Flowsheet for fermentation process……………………………………………40
10-world Ethylene prices……………………………………………………………45
11-Flowsheet for ethylene hydration process…………………………………..47
12-Hysys starting window……………………………………………………………55
13-Hysys fluid package………………………………………………………………56
14-selecting components……………………………………………………………57
15-Reactions in Hysys………………………………………………………………….59
16-First compressor K-100…………………………………………………………….60
17-First mixer (Mix-100)………………………………………………………………..61
18-First Heater (E-100)…………………………………………………………………62
19-Heat Exchanger (E-101)…………………………………………………………..63
20-mass fraction of reactor feed stream…………………………………………64
21-First Reactor…………………………………………………………………………65
22-Stream 3 mass flows……………………………………………………………….67
23-Absorber…………………………………………………………………………….68
24-Absorber design……………………………………………………………………68
25-mass fraction of stream 4…………………………………………………………69
26-recyclestream………………………………………………………………………69
27-1st distillation column………………………………………………………………70
28-1st distillation column design……………………………………………………...71
29-1st distillation column specification……………………………………………..72
30-mass flow of stream 8………………………………………………………………72
31-mass flow stream 9…………………………………………………………………73
32 -2nd Distillation column……………………………………………………………..74
33- 2nd Distillation column design……………………………………………………75
34 - 2nd Distillation column specification……………………………………………75
35-Second Reactor…………………………………………………………………….76
36- 3rd distillation column……………………………………………………………….77
37 - 3rd distillation column design…………………………………………………….78
38 - 3rd distillation column specification……………………………………………78
39 -4th distillation column……………………………………………………………….79
40- 4th distillation column design………………………………………………………80
41- 4th distillation column specification………………………………………………80
42- mass flow of stream 18………………………………………………………………81
6
43- 5th distillation column………………………………………………………………..82
44- 5th distillation column design………………………………………………………83
45 - 5th distillation column specification……………………………………………..83
46 – mass flow of stream 20 ……………………………………………………………84
47 – schematic of typical distillation column……………………………………….96
48- stripping section ……………………………………………………………………..96
49 –enriching section…………………………………………………………………….97
50 – Bubble cap tray……………………………………………………………………..98
51 – valve tray……………………………………………………………………………..98
52- sieve tray……………………………………………………………………………….99
53 – liquid and vapor tray column……………………………………………………..99
54 – packing trays………………………………………………………………………..100
55-flooding velocity for sieve trays…………………………………………………….106
56-selection of liquid flow arrangement………………………………………………109
57 – relation between downcomer and weir length……………………………….110
58 – weep point correlation……………………………………………………………..111
59- discharge coefficient for sieve tray………………………………………………112
60- entrainment correlation for sieve trays……………………………………………115
61- relation between angle and chord height………………………………………116
62- relation between hole area and pitch……………………………………………117
63-PBR ………………………………………………………………………………………..129
64- vertical separator principle………………………………………………………….141
65- vertical separator………………………………………………………………………143
66-Absorber…………………………………………………………………………………..148
67-shell and tube heat exchanger………………………………………………………167
68- structure of shell and tube heat exchanger………………………………………168
69-compressors types ………………………………………………………………………194
70-centrifugal compressor…………………………………………………………………195
71-cash flow diagram………………………………………………………………………230
72-Net present values……………………………………………………………………….231
73-cumulative cash positions………………………………………………………………234
74-PBP vs cumulative number of date points…………………………………………..236
7
List of Tables:
1-World ethanol production from 2008-2012……………………………………………….15
2- monoxide properties…………………………………………………………………………19
3- hydrogen properties………………………………………………………………………….21
4- catalysts ……………………………………………………………………………………….28
5 – ethanol properties……………………………………………………………………………31
6-acetaldehyde properties………………………………………………………………….…33
7- acetic acid properties……………………………………………………………………….34
8-ethyl acetate properties……………………………………………………………………...35
9- ethylene properties……………………………………………………………………………43
10 – water properties…………………………………………………………………………….44
11 – comparison between the three process……………………………………………….48
12- comparison between fermentation and syngas processes…………………………49
13- mass flow feed………………………………………………………………………………..60
14 – effect of changing the conversion in the first reactor………………………………66
15- summary of columns………………………………………………………………………..85
16 – summary of reactors……………………………………………………………………….86
17 – summary of heat exchangers……………………………………………………………86
18 – summary of compressors………………………………………………………………….86
19- summary of separator……………………………………………………………………....87
20- summary of energy streams………………………………………………………………..87
21- stream information overall plant……………………………………………………….....88
22- nomenclature for distillation column……………………………………………102-103
23- Specification sheet for first distillation column (T-101)………………………………120
24- Specification sheet for second distillation column (T-102)…………………………121
25 - Specification sheet for third distillation column (T-103)…………………………….123
26 - Specification sheet for fourth distillation column (T-104)…………………………..124
27 - Specification sheet for fifth distillation column (T-105)……………………………..125
28 - Specification sheet for first reactor (CRV-100)……………………………………….138
29 - Specification sheet for second reactor (CRV-101)………………………………….140
30 – nomenclature for separator……………………………………………………….144-145
31 - Specification sheet for separator (V-100)…………………………………………….147
32 - Specification sheet for Absorber (T-100)………………………………………………165
33 – nomenclature for Heat Exchanger…………………………………………………….171
34 - Specification sheet for first heater (E-100)…………………………………………….191
35 - Specification sheet for second heater ( E101)……………………………………….192
36 - Specification sheet for heat exchanger (E-102)……………………………………..193
37- Specification sheet for first compressor (K-100)………………………………………202
38 - Specification sheet for second compressor (K-101)………………………………..203
39 – Hazop Analysis on Distillation column (T-104)………………………………………..215
40 – NFPA 704 classification of the components………………………………………….222
41 – Equipment cost……………………………………………………………………….224-225
42 – utilities summary……………………………………………………………………………227
43 - Cost of raw materials, products and waste water treatment..............................228
8
Chapter 1
Literature survey
9
Introduction
The production of renewable fuels such as ethanol has received considerable
attention in recent years for its use in automobiles and as a potential source of
hydrogen for fuel cells. .
The environmental deterioration resulting from the over-consumption of
petroleum-derived products, especially the transportation fuels, is threatening the
sustainability of human society.
Ethanol- both renewable and environmentally friendly- is believed to be one of the
best alternatives, leading to a dramatic increase in its production capacity.
Currently, the most desirable product that can be formed from syngas is ethanol.
Ethanol is already in use as a biofuel, but it has only replaced a small percentage of
petroleum-based fuels. Ethanol needs to be produced from low-value feedstocks in
order to be highly marketable. While promising technologies are currently being
developed to convert the cellulosic content of plants to ethanol, these methods are
only able to convert about 50% of the plant material to ethanol. However, the
gasification of
plant biomass results in over 90% of the plant material being converted into
syngas.
Currently over 90% of Ethanol production in the USA comes from traditional grain
fermentation processes using corn, wheat or barley. Syntec technology focuses on
an entirely different Ethanol production process by using a Gasification-Catalytic
Synthesis, which is a thermo-chemical process that converts Syngas into Ethanol.
Unlike the current fermentation processes, Syntec’s catalysts will produce Ethanol
from unlimited sources of feedstock using waste gas, such as biogas from landfills,
sewage, manure, wood waste, and producer gas (thermal gasification of biomass or
other carbonaceous material such as municipal solid waste). This process will also
create far greater green house gas (GHG) reductions and carbon credits than the
fermentation process.
10
Syngas
Routes
For
fermentation
Producing
ethanol
Ethylene
hydration
11
History
Ethanol has been used by humans since prehistory as the intoxicating ingredient
of alcoholic beverages. Dried residue on 9,000-year-old pottery found in China
imply that Neolithic people consumed alcoholic beverages.
Although distillation was well known by the early Greeks and Arabs, the first
recorded production of alcohol from distilled wine was by the School of Salernoal
chemists in the 12th century. The first to mention absolute alcohol, in contrast with
alcohol-water mixtures, was Raymond Lull.
In 1796, Johann Tobias Lowitz obtained pure ethanol by filtering distilled ethanol
through activated charcoal. Antoine Lavoisier described ethanol as a compound of
carbon, hydrogen, and oxygen, and in 1808 Nicolas-Théodore de
Saussure determined ethanol’s chemical formula. Fifty years later,Archibald Scott
Couper published the structural formula of ethanol. It is one of the first structural
formulas determined.
Ethanol was first prepared synthetically in 1826 through the independent efforts of
Henry Hennel in Great Britain and S.G. Sérullas in France. In 1828,Michael
Faraday prepared ethanol by acid-catalyzed hydration of ethylene, a process
similar to current industrial ethanol synthesis.
Ethanol was used as lamp fuel in the United States as early as 1840, but a tax
levied on industrial alcohol during the Civil War made this use uneconomical. The
tax was repealed in 1906. Original Ford Model T automobiles ran on ethanol until
1908. With the advent of Prohibition in 1920, ethanol fuel sellers were accused of
being allied with moonshiners and ethanol fuel fell into disuse until late in the 20th
century.
12
Uses of Ethanol
1-As a fuel
Largest single use of ethanol is as a motor fuel and fuel additive. More than any other major
country, Brazil relies on ethanol as a motor fuel. Gasoline sold in Brazil contains at least 25%
anhydrous ethanol. Hydrous ethanol (about 95% ethanol and 5% water) can be used as fuel in
more than 90% of new cars sold in the country. And it has advantages:
-Reduces CO emissions.
- Ethanol reduces greenhouse gas (CO2) emissions.
- Adding ethanol dilutes the concentration of aromatics in gasoline reducing
emissions of some air toxics such as benzene.
2-Alcoholic beverages
Ethanol is the principal psychoactive constituent in alcoholic beverages, with depressant effects
on the central nervous system
3-Feedstock
Ethanol is an important industrial ingredient and has widespread use as a base chemical for other
organic compounds. These include ethyl halides, ethyl esters, diethyl ether, acetic acid, ethyl
amines, and to a lesser extent butadiene.
13
4-Solvent
Ethanol is miscible with water and is a good general purpose solvent. It is found in
paints, tinctures, markers, and personal care products such as perfumes and
deodorants. It may also be used as a solvent in cooking, such as in vodka sauce.
5-Drug effects
Pure ethanol will irritate the skin and eyes. Nausea, and intoxication are symptoms
of ingestion. Long-term use by ingestion can result in serious liver damage.
Atmospheric concentrations above one in a thousand are above the European
Union.
14
World production and consumption
Major findings of the old report World’s Ethanol Production Forecast 2008 – 2012:





World’s ethanol production will pass 20 Bln gallons in 2012.
Ethanol production is expected to grow in 2008 – 2012 with CAGR about 5%.
U.S. and Brazil are leading the world in production of ethanol.
Emergence of new ethanol producers in Asia and Latin America.
Cuba has the capacity to manufacture as much as 3.2 billion gallons of ethanol annually
from its sugar crop.
Factors driving ethanol market:





High oil prices.
National energy security considerations.
Ethanol tax incentives.
Improved technology – lower costs of ethanol production.
Climate change concerns.
Table(1) : World Ethanol Production Forecast 2008 – 2012 by Country,
Millions of Gallons
2008
2009
2010
2011
2012
Brazil
4,988
5,238
5,489
5,739
5,990
U.S.
6,198
6,858
7,518
8,178
8,838
China
1,075
1,101
1,128
1,154
1,181
India
531
551
571
591
611
France
285
301
317
333
349
Spain
163
184
206
227
249
Germany
319
381
444
506
569
Canada
230
276
322
368
414
Indonesia
76
84
92
100
108
Italy
50
53
55
58
60
ROW
2,302
2,548
2,794
3,040
3,286
World
16,215
17,574
18,934
20,293
21,653
15
Fig(1): Ethanol world production
Fig(2): Ethanol world production and consumption
16
We will discuss 3 process for producing ethanol:
1# Thermochemical conversion
-The process has three main steps:
1. Gasification: the biomass is dried, reduced in particle size and mechanically fed into a
gasifier. It then heated to a high temperature in an oxygen-limited steam environment to produce
synthesis gas which is then scrubbed to remove trace elements. The resulting syngas is
comprised primarily of carbon monoxide (CO) and hydrogen (H2).
2. Catalysis : the cleaned syngas is passed over a catalyst in a fixed bed reactor; the unique
Syntec catalyst converts syngas into an alcohols mixture of methanol, ethanol, propanol, butanol,
and water.
3. Purification : the alcohol mixture is dehydrated, and the water is recycled. The alcohols
are then separated to specification purity for different uses, including liquid fuels.
17
Feedstock
Syngas, or synthesis gas, a mixture of principally CO and H2, can be produced by gasification of
solid fuels, such as coal, petroleum coke, oil shale, and biomass; by catalytic reforming of
natural gas; or by partial oxidation of heavy oils, such as tar-sand oil. The syngas composition
mainly depends upon the type of resources used, their moisture content, and the gasification
process. The raw gas composition and quality
are dependent on a wide range of factors including feedstock composition, type of gasification
reactor, gasification agents, stoichiometry, temperature, pressure, and the presence or lack of
catalysts.
Gas cleanup is a general term for removing the unwanted impurities from biomass gasification
The syngas can then be converted to biofuels such as methanol, ethanol and hydrogen using
either a metal catalyst or a microbial catalyst .
Fig(3) : syngas sources and conversion processes
18
Syngas, or synthesis gas, a mixture of:
1-Carbon monoxide (CO), also called carbonous oxide, is a colorless, odorless, and tasteless
gas that is slightly lighter than air. It can be toxic to humans and animals when encountered in
higher concentrations, although it is also produced in normal animal metabolism in low
quantities, and is thought to have some normal biological functions. In the atmosphere however,
it is short lived and spatially variable, since it combines with oxygen to form carbon dioxide and
ozone.






is a flammable and highly toxic gas,
is a neutral oxide which burns in air to give carbon dioxide,
is a good reducing agent, and is used for that purpose in industry,
CuO + CO 
Cu + CO2
and, is an important industrial gas, which is widely used as a fuel.
It is also an important reducing agent in the chemical industry.
Table(2): Carbon mono xide properties
Carbon monoxide
Carbon monoxide
Carbon 19thane1919
Carbonous oxide
Carbon(II) oxide
Carbonyl
Properties
Molecular formula CO
Molar mass
28.010 g/mol
19
Appearance
colourless gas
Odor
Odorless
789 kg/m3, liquid
Density
1.250 kg/m3 at 0 °C, 1 atm
1.145 kg/m3 at 25 °C, 1 atm
Melting point
−205.02 °C, 68 K, -337 °F
Boiling point
−191.5 °C, 82 K, -313 °F
Solubility in water 27.6 mg/1 L (25 °C)
soluble in chloroform, acetic acid, ethyl
Solubility
acetate, ethanol, ammonium hydroxide,
benzene
Refractive index
(nD)
Flash point
1.0003364
−191 °C (82.2 K; −311.8 °F)
2-HYDROGEN
First element in the periodic table. In normal conditions it’s a colourless, odourless and insipid
gas, formed by diatomic molecules, H2. Its atomic number is 1 and its atomic weight 1,00797
g/mol. It’s one of the main compounds of water and of all organic matter, and it’s widely spread
not only in The Earth but also in the entire Universe.
Uses: The most important use of hydrogen is the ammonia synthesis.
Hydrogen can be burned in internal combustion engines.
Hydrogen fuel cells are being looked into as a way to provide power and research is being
conducted on hydrogen as a possible major future fuel. For instance it can be converted to and
from electricity from bio-fuels, from and into natural gas and diesel fuel, theoretically with no
emissions of either CO2 or toxic chemicals.

The gas is lighter than air.
20
Table (3) : Properties of hydrogen
Color
Colorless
Phase
gas
Density
(0 °C, 101.325 kPa)
0.08988 g/L
Liquid density atm.p. 0.07 (0.0763 solid)[2] g·cm−3
Liquid density atb.p. 0.07099 g·cm−3
Melting point
14.01 K, -259.14 °C, -434.45 °F
Boiling point
20.28 K, -252.87 °C, -423.17 °F
Triple point
13.8033 K (-259°C), 7.042 kPa
Critical point
32.97 K, 1.293 Mpa
Heat of fusion
(H2) 0.117 kJ·mol−1
Heat of vaporization (H2) 0.904 kJ·mol−1
Molar heat capacity (H2) 28.836 J·mol−1·K−1
21
We can get syngas from :
Gasification
In the gasification process, steam or oxygen (in the form of air or pure oxygen in lower than
stoichiometric amounts) are fed to a gasifier at high temperatures (greater than 700°C) to convert
carbonaceous biomass into CO, CO2 and H2 .
The gasification of carbonaceous biomass occurs via three main reactions—partial oxidation
(equation 1), complete oxidation (equation 2), and the water gas reaction (equation 3)
(McKendry, 2002b).
C + ½O2 → CO
C + O2 → CO2
ΔH298K = -268 KJ/mol
ΔH298K = -406 KJ/mol
C + H2O → CO + H2
(1)
(2)
ΔH298K = 118 KJ/mol
(3)
In addition, the water gas shift reaction plays an important role in the composition of the CO,
CO2, and H2 (equation 4).
CO + H2O → CO2 + H2
(4)
CO2 is produced inside the gasifier, due to the combustion reactions present, aimed at
supplying the heat for gasification and shift reaction, always present. For catalytic synthesis,
carbon dioxide concentration is usually limited, so it will probably have to be removed.
Therefore,a carbon dioxide removal process must be considered, for which there are a large
number technologies and processes available, e.g. it could be divided into physical and
chemical separation processes. Most spread processes are Selexol, Rectisol, Purisol, MEA,
DEA etc. Depending on the purity required and carbon dioxide concentration to be purified a
specific technology will be selected.
22
Gasification Reactors:
Several different types of gasifiers can be used to produce syngas from biomass :
1-Counter-current fixed bed (updraft) gasifiers consist of a fixed bed of biomass with a
counter current flow of steam, oxygen and/or air flowing upward through the fuel bed.
2- Co-current fixed bed (downdraft) gasifiers are similar to updraft gasifiers except that the
steam, oxygen or air flows co-currently downward with the fuel.
3- entrained flow gasifiers, the fuel is fed either as a dry pulverized solid or a fuel slurry in
tandem with oxygen (or sometimes air).This gasifier has the highest operating temperature and
pressure, which decreases the amount of tars and methane formed during gasification.
4- The fuel in a fluidized bed gasifier is gasified in an oxygen/air and steam mixture. Fluidized
beds work particularly well for biomass, as biomass resources contain higher levels of corrosive
ashes that can harm fixed bed reactors.
Fig(4): Gasification Basics
23
Process(1) Ethanol Production From Syngas
Ethanol synthesis involves the reaction between CO and H2 under high pressures (800 to 2500
psig) and moderate temperatures (180 to 350°C) .
There are several other side reactions that produce :
acetaldehyde,acetic acid and ethyl acetate.
We have in this plant:
- 5 distillation columns (T-101,T-102,T-103,T-104,T-105)
- 2 Reactors ( CRV-100 , CRV-101)
- 1 Absorber ( T-100)
- 1 Seprator ( V-100)
- 2 Heat Exchanger ( E-101 , E-102) and 1 heater (E-100)
- 2 Compressors (K-100 , K-101)
24
Flow sheet
Fig(5): Flow sheet producing syngas
25
Process Description
The fresh feed to the process consists of mixture of carbon monoxide and hydrogen. It has mass
ratio H2:CO equal 2:1, but it should enter the reactor with a mass ratio H2:CO equal 3:1 after we
recycled the unreacted feed.
Clean syngas with total flow rate equal 172030 Ib/h , temperature equal 100 F and pressure
equal 300 psia is sent to air compressor (K-100) which raised its pressure to 1038 psia.
Then it mixed the recycled stream and sent to heat exchanger (E-100) and heater (E-101) to
raise its temperature and pressure to 617 F and 1640 psia before entering the first reactor (CRV100) which assumed to be a fixed-bed tubular design (PBR) where it reacts with the catalyst
(Rh/SiO2) to produce ethanol and side products. The effluent of the reactor sent to cooler (E102) for cooling it by cooling water before entering the flash drum,vertical V-L separator(V100) to separate H2 for recycling it back to the feed.
The bottom effluent from the separator sent to absorber (T-100) where the product from the top
has CO to recycle it with H2 back to the feed and the bottom of the absorber enter The first
distillation where we separate acetaldehyde from other components in the top stream. Then the
liquid product is sent to the second distillation column (T-102) to separate ethyl acetate in the top
product which sent to the second reactor (CRV-101) which is also packed bed reactor for
producing more ethanol. The effluent from the second reactor mixed with water stream to enter
the third distillation (T-103) to separate ethyl acetate in the top product for recycling it to mix
with the feed for the second reactor.
The bottom product from the second and the third distillation are mixed and enter the the fourth
distillation (T-104) to separate our main product –ethanol- in the top product which then sent to
storage tanks with total flow rate of 74818 (Ib/hr) , 77 c and 14 psia. Finally the bottom product
enters the final distillation (T-105) to remove acetic acid from waste water.
26
Reactions:
The main reactions are:
2CO(g) + 4H2(g) → C2H5OH(g) + H2O(g)
Reaction Kinetics
The formation of higher alcohols is generally assumed to be a combination of hydrogenation and
carbon-carbon bonding via aldol reaction and CO insertion reaction.
2CO(g) + 4H2(g) → C2H5OH(g) + H2O(g)
ΔH0298 = −253.6kJ/mol of ethanol
ΔG0298 = −221.1kJ/mol of ethanol
The synthesis reaction are exothermic and release a large amount of heat therefore, maintaining
constant reaction temperature is an important design consideration, which is
removed from the reactor by vaporizing boiler feed water on the shell side of the reactor.
The side reactions:
- In the first reactor we have 3 side reactions:
1- Ethanol  Acetaldehyde + hydrogen
2- Ethanol + water  acetic acid + hydrogen
3- Ethanol + acetic acid  Ethyl acetate + water
The second reactor has one reaction :
Ethyl acetate + water  ethanol + acetic acid
27
Catalyst:
However, the catalytic conversion of syngas to ethanol remains challenging, and no commercial
process exists as of today although the research on this topic has been ongoing for 90 years. The
utilized catalysts can be classified into three categories: modified FTS catalysts, Groups VI-VIII
metal-based catalysts and modified methanol synthesis catalysts. Among the choice of the
catalysts.
Rh appears to be one of the most adaptable elements in transition metal series, and tends to yield
alcohol synthesis catalysts with high selectivity towards ethanol, but these catalysts
are too expensive to apply, however, because Rh metal is very expensive, the improvement of
the activity and the selectivity for ethanol over Rh-based catalysts is necessary for achieving a
commercial available process.
Preperation of the catalyst:
The Rh/SiO2 catalyst was prepared by the impregnation of SiO2 (JRC-SIO-1, 300m2 g−1) with
an aqueous solution of Rh(NO3)3. The sample was then dried at 373Kfor 24 h, and finally
calcined at 723K for 3 h. The Rh loading was 2 wt% in the sample.
Table(4) different Catalyst used at temperature 548 k
28
Hydrocarbons were formed over each Rh-based catalyst and the amount was in
an order of Rh/ZrO2 > Rh/SiO2 > Rh/MgO > Rh/CeO2.
Zr4+ ions could be introduced into the CeO2 lattices to form a solid solution when x was less
than 0.2 in Rh/Ce1−xZrxO2. Rh/Ce0.8Zr0.2O2 showed the highest CO conversion and the
highest selectivity for ethanol among various Rh/Ce1−xZrxO2 catalysts.
Types of major equipments
Reactor: There are 3 types of reactor that can be used in ethanol:
1. Consist of a shell and tube exchanger where catalyst is placed inside the
tubes.
Figure (6): Reactor of shell and tube
2. fluidized bed reactor which can be divided into circulating fluidized bed
(synthol, developed by sasol) and the fixed(advanced synthol)
29
3. Slurry phase reactor where the solid catalyst is suspended in circulating
mineral oil.
Figure(7): slurry reactor
Our plant reactors are packed bed reactors like in the first type.
30
Products:
Major product :Ethanol
Physical and Chemical Properties for ethanol
Ethanol is a volatile, colorless liquid that has a slight odor.It burns with a smokeless blue flame
that is not always visible in normal light.
Table(5): Physical and Chemical Properties for ethanol
Property
Value
IUPAC Name
Ethanol
Other Name
Ethyl Alcohol
Molecular Formula
C2H5OH
31
Appearance
colorless clear liquid
Molar Mass
46.06844 g/mol
Density (Liquid)
0.789 g/cm³
Flash Point
286.15 K
Boiling Point
78.4 °C
Solubility in water
Fully miscible
Viscosity
1.200 cp @ 20 °C
Chemical structure of ethanol
The properties of ethanol stem primarily from the presence of its hydroxyl group
and the shortness of its carbon chain. Ethanol’s hydroxyl group is able to
participate in hydrogen bonding, rendering it more viscous and less volatile than
less polar organic compounds of similar molecular weight. Ethanol, like most
short-chain alcohols, is flammable, has a strong odor, volatile and a colorless liquid
with a pleasant smell. It is completely miscible with water and organic solvents
and is very hydroscopic.
32
Side products
There are side reactions which produce : Acetaldehyde, Acetic acid and Ethyl
Acetate.
-Acetaldehyde :
(Systematically 33thane33) is an organic chemical compound with the formula CH3CHO,
sometimes abbreviated by chemists as MeCHO (Me = methyl). It is one of the most important
aldehyes, occurring widely in nature and being produced on a large scale industrially.
Table(6): Physical and Chemical Properties for Acetaldehyde
Molecular formula
C2H4O
Molar mass
44.05 g mol−1
Appearance
Colourless liquid
Pungent, fruity odor
Density
0.788 g cm−3
Melting point
−123.5 °C, 150 K, -190 °F
Boiling point
20.2 °C, 293 K, 68 °F
Solubility in water
soluble in all proportions
33
-Acetic acid:
is an organic compound with the chemical formula CH3CO2H
Acetic acid is a chemical reagent for the production of chemical compounds. The largest single
use of acetic acid is in the production of vinyl acetate monomer, closely followed by acetic
anhydride and ester production.
Vinegar is typically 4-18% acetic acid by mass. Vinegar is used directly as a condiment, and in
the pickling of vegetables and other foods.
Table(7): Physical and Chemical Properties for Acetic acid
Molecular
formula
C2H4O2
Molar mass
60.05 g mol−1
Exact mass
60.021129372 g mol-1
Appearance
Colorless liquid
Density
1.049 g cm-3
Melting point
16-17 °C, 289-290 K, 61-62 °F
Boiling point
118-119 °C, 391-392 K, 244246 °F
Solubility in water Miscible
log P
-0.322
34
3-Ethyl acetate:
An organic compound with the formula CH3COOCH2CH3. This colorless liquid has a
characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers,
and cigarettes. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large
scale for use as a solvent.
Table(8): Physical and Chemical Properties for Ethyl acetate
Molecular formula
C4H8O2
Molar mass
88.105 g/mol
Appearance
colorless liquid
Density
0.897 g/cm³, liquid
Melting point
−83.6 °C, 190 K, -118 °F
Boiling point
77.1 °C, 350 K, 171 °F
Solubility in water
8.3 g/100 mL (20 °C)
Solubility in ethanol,
acetone, diethyl ether,
benzene
Miscible
Refractive index (nD)
1.3720
35
2# Fermentation
-Syngas fermentation
It is a microbial process. In this process syngas which is used as carbon and
energy sources converted into fuel and chemicals by microorganisms. The main
products of syngas fermentation include ethanol, butanol, acetic acid, butyric acid,
and methane. The microorganisms are mostly known as acetogens including
Clostridium ljungdahlii, Clostridium autoethanogenum, Eurobacterium limosum,
and Clostridium carboxidivorans
This process has advantages over a chemical process since it takes places at lower
temperature and pressure, has higher reaction specificity, tolerates higher amounts
of sulfur compounds, and does not require a specific CO:H2.
The limitation of this process:
1-Gas-liquid mass transfer limitation
2- Low volumetric productivity .
3- Inhibition of organisms.
4- At high partial pressures, nitric oxide (NO) and carbon monoxide (CO)
contaminants in the syngas which can inhibit the hydrogenase enzyme that is
involved in the conversion of syngas to ethanol.
36
Fermentation Reactors
Several reactor designs can be used for the fermentation process. Trickle-bed reactors (TBR)
consist of a vertical tubular reactor, packed with solid material that the microorganisms can
attach to.
Continuous stirred-tank reactors (CSTR) are commonly used in syngas fermentation.
Ethanol is not currently produced on a commercial basis using microbial fermentation of syngas.
Another feed stock for Fermentation process:
Ethanol can be prepared by the fermentation of sugar (e.g., from molasses), which
requires an enzyme catalyst that is present in yeast; or it can be prepared by the
fermentation of starch (e.g., from corn, rice, rye, or potatoes), which requires, in
addition to the yeast enzyme, an enzyme present in an extract of malt. The
concentration of ethanol obtained by fermentation is limited to about 10% since at
higher concentrations ethanol inhibits the catalytic effect of the yeast enzyme. For
non-beverage uses ethanol is more commonly prepared by passing ethylene gas at
high pressure into concentrated sulfuric or phosphoric acid to form the
corresponding ester; the acid-ester mixture is diluted with water and heated,
forming ethanol by hydrolysis, and the alcohol is then removed from the mixture
by distillation, usually with steam.
C6H12O6 → 2 CH3CH2OH + 2 CO2
C12H22O11 + H2O → 4 CH3CH2OH + 4 CO2
37
How ethanol is currently produced from corn?
Ethanol is produced primarily from starch in corn kernels. Ethanol production from
corn grain involves one of two different processes: Wet milling or dry milling. In
wet milling, the corn is soaked in water or dilute acid to separate the grain into its
component parts (e.g., starch, protein, germ, oil, kernel fibers) before converting
the starch to sugars that are then fermented to ethanol. In dry milling, the kernels
are ground into a fine powder and processed without fractionating the grain into its
component parts. Most ethanol comes from dry milling. Key steps in the dry mill
ethanol-production process include:
1. Milling. Corn kernels are ground into a fine powder called “meal.”
2. Liquefying and Heating the Cornmeal. Liquid is added to the meal to
produce a mash, and the temperature is increased to get the starch into a
liquid solution and remove bacteria present in the mash.
3. Enzyme Hydrolysis. Enzymes are added to break down the long
carbohydrate chains making up starch into short chains of glucose (a simple
6-carbon sugar) and eventually to individual glucose molecules.
4. Yeast Fermentation. The hydrolyzed mash is transferred to a fermentation
tank where microbes (yeast) are added to convert glucose to ethanol and
carbon dioxide (CO2). Large quantities of CO2 generated during
fermentation are collected with a CO2 scrubber, compressed, and marketed
to other industries (e.g., carbonating beverages, making dry ice).
5. Distillation. The broth or “beer” produced in the fermentation step is a
dilute ethanol solution containing solids from the mash and yeast cells. The
beer is pumped through many columns in the distillation chamber to remove
ethanol from the solids and water. After distillation, the ethanol is about
96% pure. The solids are pumped out of the bottom of the tank and
processed into protein-rich co products used in livestock feed.
6. Dehydration. The small amount of water in the distilled ethanol is removed
using molecular sieves. A molecular sieve contains a series of small beads
that absorb all remaining water. Ethanol molecules are too large to enter the
sieve, so the dehydration step produces pure ethanol . Prior to shipping the
ethanol to gasoline distribution hubs for
38
Block flow diagram of the fermentation process.
Fig(8):Block flow diagram of the fermentation process.
39
Flow sheet
Fig(9): Flow sheet for corn fermentation process for producing ethano
40
Process description
The most common processes in conventional corn-based ethanol production are
known as dry grind (DGP) and wet mill. The DGP is usually the preferred choice
and also in this work it is adopted as a reference. A generic simplified ethanol plant
is simulated by means of a process simulator (Aspen PlusTM) in order to have a
sensible base case for the sensitivity and financial analyses.
In the first plant section, the corn is milled down to the proper particle size (<2mm)
in order to facilitate the subsequent penetration of water and is sent to a slurry tank
together with approximately 68,500 kg/h of process water. The slurry is “cooked”
by using steam at 4 bar: the process temperature (110 ◦C) allows the sterilization of
the slurry and breaks the starch hydrogen bonds so that water can be absorbed (the
starch granules swell and increase the surface area). This step is termed
gelatinization because the resulting mixture has a highly viscous, gelatinous
consistency.
The following liquefaction step (85 ◦C) is accomplished by the action of _-amylase
enzyme on the exposed starch molecules. _-Amylase is added at 0.082% (dry basis
with respect to corn, db): the effect is a random breakage of the α1,4 glucosidic
41thane41 and amylopectin linkages, thus
decreasing the viscosity. The mash from the liquefaction vessel is added to a
backset stream and cooled down to 35 ◦C, ready for the fermentation step.
In the fermentation reactor, a simultaneous saccharification and fermentation (SSF)
occurs: starch oligosaccharides are almost completely hydrolysed (99%) into
glucose molecules by glucoamylase enzyme (added at 0.11% db); the yeasts
(Saccharomices cerevisiae) catalyse the reaction:
C6H12O6→ 2C2H5OH + 2CO2. (1)
41
The outlet stream from the fermenter (beer) contains also small quantities of
several secondary products such as acetaldehyde, methanol, butanol, acetic acid
and glycerol. Our simulation model considers only the last two species, obtained
through the reaction:
2C6H12O6+H2O → C2H4O2+2C3H8O3+CH3CH2OH + 2CO2. (2)
All reactors were modeled simply by assuming a fixed conversion: 99% of starch
is hydrolyzed.
Reaction (1) converts 99.5% of glucose, while the remaining 0.5% is transformed
by reaction
(2) all conversions are expressed on a weight basis. The heat of reaction is set to
1200 kJ/kg of ethanol .
In general, this process needs a large amount of water and, therefore, it is important
to recover and recycle as much of it as possible in order to minimize the overall
make up. After our analysis the makeup has been reduced to a little bit more than
8,000 kg/h of process water and 8,400 kg/h of cooking steam (excluding the water
required by cooling towers’ and boilers ‘make ups, if needed).
42
3#Ethylene hydration
Ethylene (IUPAC name: 43thane) is an organic compound, a hydrocarbon with the
formula C2H4 or H2C=CH2
Ethylene is widely used in chemical industry, and its worldwide production (over 109
million tonnes in 2006) exceeds that of any other organic compound. Ethylene is also an
important natural plant hormone, used in agriculture to force the ripening of fruits.
Table(9): Physical and Chemical Properties for Ethylene
Molecular formula
C2H4
Molar mass
28.05 g/mol
Appearance
colorless gas
Density
1.178 kg/m3 at 15 °C, gas
Melting point
−169.2 °C (104.0 K, -272.6 °F)
Boiling point
−103.7 °C (169.5 K, -154.7 °F)
Solubility in water
3.5 mg/100 mL (17 °C) ;
2.9 mg/L
Solubility in ethanol 4.22 mg/L
43
Table(10): Physical and Chemical Properties for H2O
Properties
Molecular
H2O
formula
Molar mass
18.01528(33) g/mol
Appearance
white solid or almost colorless,
transparent, with a slight hint of
blue, crystalline solid or liquid [2]
Density
1000 kg/m3, liquid (4 °C) (62.4
lb/cu. Ft)
917 kg/m3, solid
Melting point
0 °C, 32 °F, (273.15 K)[
Boiling point
99.98 °C, 211.97 °F (373.13 K)
Acidity (pKa)
15.74
~35–36
Basicity (pKb)
15.74
Refractive
index (nD)
1.3330
Viscosity
0.001 Pa s at 20 °C
44
World Ethylene Prices
World Ethylene Spot Prices
80
70
60
40
c/lb
50
30
20
10
0
ETUS…
Fig(10):World Ethylene Prices
In light of new market conditions, we are consider the direct hydration
of ethylene using a zirconium tungstate catalyst.
45
Process Description
The raw ethylene feed for this process is supplied to the plant via a pipeline at a pressure of 50
atm and ambient temperature. The fresh ethylene is first mixed with recycled ethylene-rich gas,
Steam 20, prior to mixing with boiler feed water, Stream 3. The resulting stream, Stream 4, is
then sent to heat exchanger E-201 where the stream is vaporized and heated to approximately
227°C. Stream 5 leaving this exchanger is sent to a gas-phase adiabatic reactor containing a bed
3
of 100 m of zirconium tungstate catalyst.
The reactor effluent, Stream 6, is then cooled and partially condensed in heat exchanger E-202
prior to being throttled to a pressure of 500 kPa and sent to the high-pressure separator, V-201.
The liquid leaving V-201 Stream 10, is flashed to a pressure of250 kPa and fed to the lowpressure separator. The vapor from the low-pressure
separator, Stream12, is compressed in C-201 and mixed with the vapor from the high-pressure
separator prior to being fed to the ethanol absorber, T-201. Process water is fed to the top of the
absorber to scrub out small amounts of ethanol. The liquid stream from the low-pressure
separator, Stream 22, contains most of the ethanol and is fed to a heat exchanger, E-203, where it
is vaporized prior to being fed to a tray tower, T-202. In this tower, an ethanol-rich stream,
containing approximately 90 mol% of ethanol is taken as a top product. The stream leaving the
bottom of the absorber, T-201, is also sent to the ethanol purification tower to recover ethanol.
The bottom stream from T-202 is water containing a small amount of ethanol that is cooled to
40°C in heat exchanger.
E-207 prior to being sent to waste water treatment. It should be noted that the overhead of T-202
uses a partial condenser because there is a small amount of ethylene in the feed to the column
that cannot be totally condensed. The overhead vapor stream is sent to a heat exchanger, E-206,
where it is cooled to 50°C, and most of the stream is condensed. The non-condensable portion is
mixed with the ethylene recycle purge, Stream 29, and this combined stream is sent to the boiler
house as fuel gas that is used to raise steam.
The vapor leaving the absorber, Stream 16, is split, with the majority being sent to the recyclegas compressor, C-202, where it is pressurized and recycled to mix with fresh ethylene feed. A
small portion of the absorber overhead product is purged, in Stream 29, to control the buildup of
non-condensable in the recycle loop. This purge is combined with the off-gas from T-202 to
produce a fuel-gas stream.
46
Flow sheet
Fig(11): Flow sheet for Ethylene hydration process
47
Main Reaction
Comparison
-Cost of raw material
Table(11): Cost for raw material of the 3 process
Row material
Syngas
Fermentation (corn)
Ethylene hydration
5$/KG
12.5$/KG
1.3$/KG
Current capital cost per annual gallon of installed capacity for an ethanol plant ranges from $1.25
to $2.00. For example, a 40 million gallon per year plant may cost nearly $80 million. Capital
cost per annual gallon tends to decrease with plant size. A 100 million
gallon per year ethanol plant may have a capital cost of approximately $125 million.
The production cost of a gallon of alcohol produced using a thermo chemical route is $1.07
based on a feedstock cost of $35 per ton. This is expected to drop to under $1.00 per gallon as
performance of the gasification process and catalyst is improved and optimized.
48
The following cost comparison was prepared by Syntec. (A Canadian, scientific research
company, located in British Columbia)The US$2.33/gallon capital cost and US$0.78/gallon
production cost are based on Syntec engineering consulting firm, Plant Process Equipment Inc,
Houston.
Table(12) Plant Process cost for Enzyme/Fermentation and
Gasification/Synthesis Syntec Biofuel.
Enzyme/Ferme
Theoretical
yield
ntation
hesis
e.g., Iogen Canada
Syntec Biofuel Inc.
114 gal/ton
Actual yield
70 gal/ton
Approx. capital
$4.45
cost/gallon/year
Approximate cost/gallon
Syngas/Synt
(IEA2002 est.)
$1.44
(IEA 2002 est.)
230 gal/ton
114 gal/ton
(Syntec est.)
$2.33 (PPE
est.)
$0.78(PPE
est.)
49
The main advantages of the thermo chemical pathway for ethanol production (over the biological
routes) are:
1-Higher flexibility regarding feedstock. There is no need to use clean homogeneous raw
material, moreover, the cellulose content or any other chemical composition is not decisive for
technical feasibility of the gasification.
2-Higher flexibility regarding products. Considering the syngas produced in gasification as a
link, different products could be obtained, such as multiple fuels, hydrogen, heat, steam, energy
etc, so, many synergies can be expected.
3-Low operational costs, due to feedstock flexibility and thermal integration which can be
achieved the thermo chemical processes
Discussion of the three process
After we had seen the comparison and because we are not a an agricultural country
so we couldn’t produce corn to use it in fermentation process as feed stock and the
promising technologies are currently being developed to convert the cellulosic
content of plants to ethanol, these methods are only able to convert about 50% of
the plant material to ethanol .
One advantage of the use of syngas to produce fuels is that syngas can be produced
from waste materials that would otherwise need to be discarded. Instead of placing
waste products in landfills or the ocean, these waste products can be used to
generate a useful, energy rich product .This makes the syngas conversion process
both an efficient means of producing energy and an environmentally friendly
option for the recycling of waste products so ethanol production from syngas
seems to be marketable in the very near future.
50
Chapter 2
Hysys simulation
and material balan
51
ABSTRACT :
In this report we used the simulation software hysys to
simulate ethanol production from syngas by completed
material balance, and we will mention in detail about all
equipment we used. Various data were recovered from
different resources and assumptions have been made to
simplify the simulation process.
52
INTRODUCTION :
Our Process is Ethanol Production From Syngas
Ethanol considered as renewable fuel which has received attention in recent years
for its use in automobiles and as a potential source of hydrogen for fuel cells .
Ethanol synthesis involves the reaction between CO and H2 ( syngas) under high
pressure = 1640 psia and temperature = 617 F
The main reactions are:
2CO(g) + 4H2(g) → C2H5OH(g) + H2O(g)
There are several other side reactions that produce : acetaldehyde,acetic acid and
ethyl acetate.
It is a catalytic reaction and the catalyst used in the reaction is Rhodium over silica
gel Rh/SiO2 catalyst.
53
HYSYS Simulation Description:
Objectives :
- To describe the how to use HYSYS simulator
-To be able to design Chemical plant using HYSYS simulator
-To introduce some other chemical design simulators.
Introduction:
HYSYS is a powerful engineering simulation tool , has been uniquely created with
respect to the program architecture ,interface design , engineering capabilities , and interactive
operation . The integrated steady state and dynamics modeling capabilities , where the same
model can be evaluated from either perspective with full sharing of process information ,
represent a significant advancement in the engineering software
industry . the various
components that comprise HYSYS provide an extremely powerful approach to steady state
modeling .At a fundamental level , the comprehensive selection of the operations and property
methods allow you to model a wide range of processes with confidence .
To comprehend why HYSYS is such a powerful engineering simulation tool, you need look no
further than
its
strong thermodynamics
foundation .The inherent flexibility contributed
through its design ,combined with the un paralleled accuracy and robustness provided by its
property package calculation leads to the presentation of a more realistic model .HYSYS is
widely used in universities and colleges in introductory and advanced courses especially in
chemical engineering .In industry , the software is used in research , development ,modeling and
design .
Getting Started:
With windows, the installation process creates a shortcut to HYSYS :
Click the icon to start HYSYS
Or
1-click on the Start menu
2-Move from Programs to Hyprotech to HYSYS
3- Select HYSYS .
54
Fig (12):HYSYS starting window
Setting your Session Preferences :
1- To start a new simulation case , do one of the following :
-
From the File menu, select New Case.
-
Click the New Case icon and the simulation basis manager will appear

Creating a fluid Package
The next step is to create a fluid Package .As a minimum , a Fluid Package contains the
Components and property method (for example , an Equation of State )HYSYS will use in its
calculations for a particular flow sheet . Depending on what is required in a specific flow sheet ,
a fluid Package may also contain other information such as reactions and interaction parameters .
1- On the Simulation Basis Manager view , click the fluid Pkgs tab.
2- Click the Add button , and the property view for your Fluid Package appears
55
Fig (13) :Specify the fluid Package
Select a Fluid Package and HYSYS will find the match to your input
We choose UNIQUAC as a fluid package because the activity coefficients can be used to
predict simple phase equilibria (vapour–liquid, liquid–liquid, solid–liquid), or to estimate
other physical properties. They are commonly used in process simulation programs to
predict the phase behavior of multicomponent chemical mixtures.
Selecting Components :
Now that you have chosen the property Package to be used in the simulation , the next step is to
select the components .
1- On the component List Selection drop-down , select Component List -1, if it is not already
existed
2- Click the view button , the Component List View appear
There are number of way to select components for your simulation . One method is to use the
matching feature . Each component is listed in three ways on the selected tab :
56

Sim Name : The name appearing within the simulation .

Full Name :IUPAC name (or similar ), and synonyms for many components

Formula : The chemical formula of the component .
At the top of each of these three columns is a corresponding radio button. Based on the selected
radio button ,HYSYS will locate the component(s) that best matches the input in the match cell
.
3- Select component and add pure
4- For other that is not exist in HYSYS , is added by the user ,Click to Add HYPO , create your
new material and fill the new material properties
Fig (14) Selecting Components
57
Selecting Reactions
Then we select reactions to set the reactions we have in the process:
-We put to sets because we have to reactors:
1-First reactor
 has the main reaction and 3 side reaction:
The main reaction : ( in the gas phase)
carbon monoxide + hydrogen  ethanol + water
2CO(g) + 4H2(g) → C2H5OH(g) + H2O(g)
The side reactions :
Ethanol  Acetaldehyde + hydrogen
C2h5OH  CH3CHO + H2
Ethanol + water  acetic acid + hydrogen
C2H5OH + H2O  CH3COOH + H2
Ethanol + acetic acid  Ethyl acetate + water
C2h5OH + CH3COOH  CH3COOCH2CH3 + H2O
2- Second reactor  has one side reaction:
Ethyl acetate + water  ethanol + acetic acid
CH3COOCH2CH3 + H2O  C2h5OH + CH3COOH
58
Fig(15): Setting reactions in one set
Entering the simulation Environment :
To leave the Basis environment and enter the Simulation environment
To leave the Basis environment and enter the simulation , do one of the following :

Click the enter Simulation Environment button on the Simulation Basis Manager view

Click the Enter Simulation Environment icon on the tool bar
When you enter the Simulation environment , the initial view is the PFD (HYSYS default
setting )
59
Process Description:
A feed stream 1 of syngas which contain hydrogen and carbon monoxide at 100 F and 300 psia is
fed to compressor K-100 to raise the pressure to 1038 psia in the outlet stream 1* and raise the
temperature to 420 F.
Table (13): Mass flow of compressor inlet feed:
Components
Mass flow( Ib/hr )
Hydrogen
18743
Carbon monoxide
153280
Fig(16): K-100
60
Fig(17): K-100 worksheet
The outlet stream 1* from compressor will enter the mixer and will mix with the
recycled stream came from the absorber by MIX-100
Fig(17): Mix-100
61
The outlet stream 2 from mixer is fed to heat exchanger E-100 with the steam at
662 F and 2397 psia in which it heated stream 2 to 592 F as in stream 2* by
exchange the the heat with a steam stream with temperature = 662 F
and a molar flow = 39000 kgmole/h.
Fig(18): E-100
The effluent stream 2* from heat exchanger is fed to heater E-101 which it heated
the stream 2** to 617 F and 1640 psia which is the appropriate condition for the
reaction in the reactor.
62
Fig(19): E-101
Fig(20):E-101 worksheet
The stream 2** enter the first reactor with a temperature = 617 F and a pressure =
1640 psia and mass fraction of :
63
Fig(20): mass fraction of feed reactor
64
Reactor 1 :
Fig(21): First reactor
- The reactor is a conversion reactor.( packed bed reactor)
- The feed enter in the gas phase and also the reactions in the gas phase.
- The reactor is isobaric reactor.
- The main reaction is exothermic so the outlet stream are high temperature.
- We choose set 1 in the reaction where it has 4 reactions : 1 main and 3 side
reactions.
:
65
After we solved the reactor the amount of ethanol that produced from the reactor is small and
under our desired amount, so we have tried to change the conversion of each reaction to get our
desired amount or approximately equal.
Table(14): explains the change of conversion for each reaction
Reactions
First Estimation
Second Estimation
Third Estimation
Rxn 1
80
70
60
Rxn 2
40
35
20
Rxn 3
40
35
20
Rxn 4
40
35
20
There are two outlet streams from the reactor:
- 2*** stream with zero flow rate because the reactions are in the vapor phase ,
since the conversion reactor gives us two streams : liquid and vapor.
- stream 3 with a temperature = 767.14 F and pressure =1640 psia , and it has a
composition mass flow as in the figure :
66
Fig(22) : stream 3 mass flow
The effluent stream 3 is fed to heat exchanger E-102 which it cooled the stream 3* to 140 F
by exchange the the heat with a water stream with temperature=77 F
and a molar flow = 30000 kgmole/h .
Stream 3 * then enter the separator (V-100) to seperate H2 and CO in the vapor phase (stream
v3) to recycle it . The liquid stream (L3) sent to absorber (T-100) to absorb all mono oxide to
recycle it . The advantage from recycling the unreacted feed:
-
To converge the syngas to get more ethanol and then high efficiency.
-
To have a constant ratio of 3:1 for H2:CO before entering the reactor.
67
Fig(23): Absorber
The number of stages we put was 10 stages and we put didn't put any specification because the
absorber doesn't need it.
Fig(24): Absorber Design
68
The outlet streams of the absorber are :
1- The overhead Stream 4 where it has only CO and H2 :
Fig(25): stream 4 mass fraction
Then stream 4 and stream v3 are mixed with (MIX-102) and sent to air compressor K101 to raise the outlet stream rec* temperature from 131 F to 154 F .
Fig(26): recycle
69
Then the stream is mixed with the feed stream 1* as we mentioned above.
The bottom stream 7 from the absorber will enter the first distilation that is called (acetaldehyde
column) .Seperation process will take place in this column. This column is used to separate
acetaldehyde (as a overhead) from other compounds.
First Ditillation (Acetaldehyde coloumn )
Fig(27): First distillation column
70
Fig(28): First distillation column design
In the first column the specifaction we add to get converged:
- Total condenser distillation coloumn.
-number of stage =10
-reflux ratio of the condenser = 5
-Distillate rate to recover acetaldehyde in stream 8 = 21600 (Ib/h)
71
Fig(29): first distillation column specification
Mass flow rate of Stream 8:
Fig(30): stream 8 mass flow
72
The bottom stream contains mainly ethanol with other compounds in stream 9 which will
enter the second column (ethyl acetate column1).
Mass flow rate of Stream 9:
Fig(31): stream 9 mass flow
In this column is used to separate ethyl acetate in the over head product and the other
components will exist from the bottom stream 11 .
Second Distillation (ethyl acetate column1)
73
Fig(32): 2nd distillation column
In the second column the specifaction we add to converged:
-number of stage = 10
-reflux ratio of the condenser = 2
-comp recovery for ethyl acetate in the upper stream=0.99
74
Fig(33):2nd distillation column design
Fig(34):2nd distillation column specification
75
The recycled stream from the third distillation(ethyl acetate column 2) will mix with the
overhead product from the second distillation by (MIX-102) to enter the second reactor at
temperature = 81 F and pressure = 15 psia.
Reactor 2 :
Fig(35): 2nd Reactor
-
The reactor is a conversion reactor. (Packed Bed Reactor)
-
The feed enter in the liquid phase and also the reactions in the liquid phase.
-
The reactor is isobaric reactor.
-
We choose set 2 which has 1 reaction :
Ethyl acetate + water  ethanol + acetic acid
76
The bottom liquid stream 13 from the reactor is sent to mixer (MIX-103) to enter the third
distillation with water( stream 14).
The third distillation ( ethyl acetate removal column)
Fig(36): third distillation
The third distillation we put to recycle ethyl acetate by getting it from the upper head stream
because we need it as a feed with water in the second reactor
At the same time the bottom stream 11 from the second distillation will be mixed with the
bottom stream from the third distillation by mixer (MIX-104) to enter the fourth
distillation(ethanol column) to separate ethanol from other compounds.
In the third column the specifaction we add to get converged:
-number of stage =10
- Pressure of the condenser and the reboiler = 15 psia
-reflux ratio of the condenser = 1
- Mass flow of H2O in the top stream 15 = 20000 (Ib/h)
77
Fig(37): third distillation design
Fig(38): third distillation specification
78
As we mentioned above the bottom streams of the second and the third distillations are
mixed together by a mixer MIX-104 to enter the fourth distillation ( Ethanol coloumn) to
separate ethanol from other components.
The fourth distillation ( Ethanol coloumn)
Fig(39): fourth distillation coloumn
This coloumn we put to recover our main product ( ethanol) and separate it from acetic acid
which will be recovered by the fifth distillation.
In the fourth column the specifaction we add to get converged:
-number of stage =25
- Pressure of the condenser and the reboiler = 15 psia
-Coponent fraction of stream 18 = 0.94 for ethanol.
- Ethanol flow rate =74300 ( Ib/h)
79
Fig(40): fourth distillation coloumn
Fig(41): fourth distillation coloumn specification
80
We get ethanol mass flow in the upper stream = 74300 (Ib/h)
Fig(42) : stream 18 mass flow
The bottom stream 19 enter the fifth distillation ( acetic acid coloumn) to recover acetic acid
in the upper stream and get rid of the waste in the bottom stream.
81
The Fifth distillation ( acetic acid coloumn)
Fig(43): Fifth distillation column
In the fifth column the specifaction we add to get converged:
-number of stage =10
- Pressure of the condenser and the reboiler = 15 psia
-reflux ratio of the condenser = 2
- H2O recovery in the upper stream –since H2O boiling point is less than acetic acid- = 0.99
82
Fig(44): Fifth distillation column design
Fig(45): Fifth distillation column
83
We get acetic acid flow rate = 24173(Ib/h)
Fig(46) : stream 20 mass flow
The bottom stream is waste , so we get rid of it
84
Process Equipments:
- Several units are involved in this process. Reactors, columns, compressors, and heat
exchangers are examples of these units so each category will be discussed briefly.
1. Columns
Table(15) :Summary of columns
Column
Name
Number of
Stages
Top
Bottom
Temperature Temperature
( F)
( F)
Top
Pressure
(psia)
Bottom
Pressure(psia)
T-100
10
97.7
128.3
14.5
14.5
T-101
10
157
254
72
72
T-102
10
149
189.9
15
15
T-103
10
79.7
178.4
15
15
T-104
25
77
210
15
15
T-105
10
211
218
15
15
85
2. Reactors:
Table(16): Summary of reactors
Reactor
Temperature(F)
Pressure(psia)
CRV-100
617
1640
CRV-101
81
15
4. Heat Exchangers , Heater and coolers:
Table(17) :Summary of Heat Exchanger,Heaters and coolers
Unit
ΔT (F)
E-100 (HE)
235
E-101 (Heater)
14
E-102 (Cooler)
350
5. Compressors:
Table(18):Summary of Compressors
Unit
ΔP(kpa)
K-100
5086
K-101
20
86
6-Separators:
Table(19):Summary of separator
Unit
V3(kg/h)
L3(kg/h)
V-100
316780
75789
- Energy Consumption:
Table(20): Summary of energy streams
Energy stream
Heat flow Q(KJ/h)
q1
3.446*107
q2
5.059*107
q3
4.366*107
q4
3.388*107
q5
5.142*107
q6
4.12*107
q7
3*107
q8
7*108
q9
7*108
q10
3.8109
q11
3.8*109
q12
1.72*108
q13
1.723*108
87
Material balance
The inlet streams are:
stream 1 + stream water1 + stream 14 = 186973.2 ( Ib/h )
The outlet streams are:
stream 8 + stream 18 + stream 20 + stream 21 = 186972.97 (lb/h)
71170 22298
31142 80970 9800.
0
3
0
38878
0
78030 38878
0
276.8
103.4
500
500
100
100
100
11307
110.4
7
2068.
4
100
Flow
rate
Pressu
re
(kpa)
88
(kg/h)
66
123.6
73.3
57.7
60
60
42
408.4
1
75.7
Temp.( 37.7
c)
4
2
Stream 1
No #
3
5
6
7
8
9
10
Table(21) :Stream information overall plant
89
27.3
103.4
55006
0
82
103.4
55006
0
Temp.(c)
Pressure
(kpa)
Flow rate
(kg/h)
12
11
Stream
No #
55006
0
103.4
25.2
13
3175.2
101.3
35
14
53054
0
103.4
29.55
15
22694
103.4
85.36
16
71565
103.4
83.557
17
35850
100
77.57
18
35715
100
98
19
34481
103.4
99
20
1233.9
103.4
103
21
Chapter 3
Equipment Design
90
Abstract:
In this report, the equipments in our ethanol plant has been designed; along with
estimating the cost of each equipment. Our plant contains variety of equipments.All
information of flow rates, temperature and pressure were taken from SRI flow sheet and
Hysys program. The resulted data are presented with detailed design procedures.
Furthermore, Excel and Polymath program are created to calculate the design
parameters.
91
Summary of Equipments Designed.
Designer
Eid Ali
Mosleh Al-Yami
Equipments Designed
1. Distillation column (T-101) .
2. First Reactor (CRV-100).
3. Seperator (V-100).
1. Distillation Column (T-103).
2. Absorber (T-100)
3. Cooler . (E-102)
1. Distillation Column (T-102).
2. Second Reactor . (CRV-101)
Yousef Bahbhani
Omar Al-Ajmy
Khalid Sulaili
1. Distillation Column (T-104).
2. Heat Exchanger (E-100).
3. Air Compressor. (K-100)
1. Distillation Column. (T-105)
2. Air Compressor (K-101).
3. Heat Exchanger (E-101)
92
Distillation Column
Distillation is defined as:
A process in which a liquid or vapor mixture of two or more substances is separated into
its component fractions of desired purity, by the application and removal of heat.
Distillation is based on the fact that the vapor of a boiling mixture will be richer in the
components that have lower boiling points.
Therefore, when this vapor is cooled and condensed, the condensate will contain more
volatile components. At the same time, the original mixture will contain more of the less
volatile material.
Distillation columns are designed to achieve this separation efficiently.
Although many people have a fair idea what “distillation” means, the important
aspects that seem to be missed from the manufacturing point of view are that:

distillation is the most common separation technique

it consumes enormous amounts of energy, both in terms of cooling and
heating requirements

it can contribute to more than 50% of plant operating costs
The best way to reduce operating costs of existing units, is to improve their efficiency
and operation via process optimisation and control. To achieve this improvement, a
thorough understanding of distillation principles and how distillation systems are
designed is essential.
93
Types of Distillation Columns
There are many types of distillation columns, each designed to perform specific types of
separations, and each design differs in terms of complexity.
Batch and Continuous Columns
One way of classifying distillation column type is to look at how they are operated. Thus
we have:
- Batch and
- Continuous columns.
Batch Columns
In batch operation, the feed to the column is introduced batch-wise. That is, the
column is charged with a 'batch' and then the distillation process is carried out. When
the desired task is achieved, a next batch of feed is introduced.
Continuous Columns
In contrast, continuous columns process a continuous feed stream. No interruptions
occur unless there is a problem with the column or surrounding process units. They are
capable of handling high throughputs and are the most common of the two types. We
shall concentrate only on this class of columns.
Types of Continuous Columns
Continuous columns can be further classified according to:
the nature of the feed that they are processing,
- Binary column - Multi-component :
94
The type of column internals
- Tray column - where trays of various designs
are used to hold up the liquid to provide better
contact between vapor and liquid, hence
better separation
- packed column - where instead of trays,
'packings' are used to enhance contact
between vapor and liquid
Basic Distillation Equipment and Operation
Main Components of Distillation Columns
Distillation columns are made up of several components, each of which is used either to
transfer heat energy or enhance material transfer. A typical distillation contains several
major components:
- A vertical shell where the separation of liquid components is carried out.
- Column internals such as trays/plates and/or packings which are used to
enhance component separations
- A reboiler to provide the necessary vaporization for the distillation process.
- A Condenser to cool and condense the vapor leaving the top of
the column.
- A Reflux drum to hold the condensed vapor from the top of the column so that
liquid (reflux) can be recycled back to the column.
The vertical shell houses the column internals and together with the condenser and
reboiler, constitute a distillation column. A schematic of a typical distillation unit with a
95
single feed and two product streams is shown below:
Figure(47) Schematic of a typical distillation column
Basic Operation and Terminology
- The liquid mixture that is to be processed is known as the feed and this is introduced
usually somewhere near the middle of the column to a tray known as the feed tray. The
feed tray divides the column into a top (enriching or rectification) section and a
bottom (stripping) section. The feed flows down the column where it is collected at the
bottom in the reboiler.
Heat is supplied to the reboiler to generate vapor. The source of heat input can be any
suitable fluid, although in most chemical plants this is normally steam. In refineries, the
heating source may be the output streams of other columns. The vapor raised in the
reboiler is re-introduced into the unit at the bottom of the column. The liquid removed
from the reboiler is known as the bottoms product or simply, bottoms.
Figure (48): Stripping Section
96
The vapor moves up the column, and as it exits the top of the unit, it is cooled by a
condenser. The condensed liquid is stored in a holding vessel known as the reflux drum.
Some of this liquid is recycled back to the top of the column and this is called the reflux.
The condensed liquid that is removed from the system is known as the distillate or top
product.
Thus, there are internal flows of vapor and liquid within the column as well as external
flows of feeds and
product streams, into
column.
and out of the
Figure(49):enriching Section
Column Internals
Trays and Plates
The terms "trays" and "plates" are used interchangeably. There are many types of tray
designs, but the most common ones are :
Bubble cap trays
A bubble cap tray has riser or chimney fitted over each hole, and a cap that covers
the riser. The cap is mounted so that there is a space between riser and cap to allow
the passage of vapor. Vapor rises through the chimney and is directed downward by
the cap, finally discharging through slots in the cap, and finally bubbling through the
liquid on the tray.
97
Figure.(50) Bubble cap tray
Valve trays
In valve trays, perforations are covered by liftable caps. Vapor flows lifts the caps, thus
self creating a flow area for the passage of vapor. The lifting cap directs the vapor to
flow horizontally into the liquid, thus providing better mixing than is possible in sieve
trays.
Figure(51): Valve tray
98
Sieve tray
Sieve trays are simply metal plates with holes in them. Vapor passes straight upward
through the liquid on the plate. The arrangement, number and size of the holes are
design parameters.
Figure(52): Sieve tray
Because of their efficiency, wide operating range, ease of maintenance and cost
factors, sieve and valve trays have replaced the once highly thought of bubble cap
trays in many applications.
We choose it because:
1- The pressure drop among the plates is small.
2- It is cheaper and has a good efficiency.
3- ease of maintenance .
4- wide operating range.
Liquid and Vapour Flows in a Tray Column
The next few figures show the direction of vapor and liquid flow across a tray, and
across a column.
Figure(53): Liquid and vapor in a tray column
Each tray has 2 conduits, one on each side, called downcomers. Liquid falls through
the downcomers by gravity from one tray to the one below it. The flow across each
plate is shown in the above diagram on the right.
99
A weir on the tray ensures that there is always some liquid (holdup) on the tray and is
designed such that the the holdup is at a suitable height, e.g. such that the bubble
caps are covered by liquid.
Being lighter, vapor flows up the column and is forced to pass through the liquid, via
the openings on each tray. The area allowed for the passage of vapor on each tray is
called the active tray area.
As the hotter vapor passes through the liquid on the tray above, it transfers heat to the
liquid. In doing so, some of the vapor condenses adding to the liquid on the tray. The
condensate, however, is richer in the less volatile components than is in the vapor.
Additionally, because of the heat input from the vapor, the liquid on the tray boils,
generating more vapor. This vapor, which moves up to the next tray in the column, is
richer in the more volatile components. This continuous contacting between vapor and
liquid occurs on each tray in the column and brings about the separation between low
boiling point components and those with higher
Packings
There is a clear trend to improve separations by supplementing the use of trays by
additions of packings. Packings are passive devices that are designed to increase the
interfacial area for vapor-liquid contact. The following pictures show 3 different types
of packings.
Figure(54): Packing trays
These strangely shaped pieces are supposed to impart good vapor-liquid contact
when a particular type is placed together in numbers, without causing excessive
pressure-drop across a packed section. This is important because a high pressure
drop would mean that more energy is required to drive the vapor up the distillation
column.
100
Packings versus Trays
A tray column that is facing throughput problems may be de-bottlenecked by
replacing a section of trays with packings. This is because:
- Packings provide extra inter-facial area for liquid-vapor contact.
- Efficiency of separation is increased for the same column height.
- Packed columns are shorter than trayed columns
Packed columns are called continuous-contact columns while trayed columns are
called staged-contact columns because of the manner in which vapor and liquid are
contacted.
We have 5 distillation columns and we will make a sample calculation on the first
distillation column (T-101)
Brief information about (T-101):
After we recycled the unreacted feed , the stream coming from the absorber we sent
it to the first distillation column to separate acetaldehyde from the other components.
Assumptions
1) Tray column.
2) Sieve plate.
3) Material of the distillation is carbon steel.
4) Plate spacing= 0.6 m
5) Efficiency = 51%
6) Flooding % = 85%
7) Weir height = 45 mm
8) Hole diameter = 4 mm
9) Plate thickness =5 mm
10) downcomer area 12% of total
101
Table (22) : nomenclatures for distillation column
Symbol
Definition
FLv
Liquid vapor flow factor
Lw
Liquid mass flow rate (kg/s)
Vw
vapor mass flow rate (kg/s)
ρv
Vapor density (kg/m 3)
ρL
Liquid density (kg/m 3)
uf
flooding vapor velocity (m/s)
u`v
flooding at maximum flow rate (kg/s)
Ac
Total column cross sectional area (m2)
Dc
Column diameter (m)
Ad
cross sectional area of down comer (m2)
An
Net area (m2)
Aa
Active area (m2)
Ah
Hole area (m2)
Aap
Clearance area (m2)
Ap
Perforated area (m2)
how
Weir crest (mm) liquid
u`h
Min. vapor velocity (m/s)
hd
Dry plate drop (mm)
hr
Residual head (mm)
102
hap
Out let weir height (mm)
hdc
Head loss in downcomer (mm)
T
thickness of cylindrical shell (in)
P
maximum allowable internal pressure (psi)
S
maximum allowable working stress (psi)
Ri
: inside radius of shell (in)
Ej
efficiency of joint expressed as fraction
Cc
allowance for corrosion (in)
Design Procedures:
1) Specify the properties of outlets streams: (flow rate, density and surface tension) for
both vapor and liquid from hysys.
2) Calculate minimum number of trays.
3) Calculate the maximum liquid and vapor outlet flow rate.
4) Choose tray spacing and then determine K1 and K2 using figure (1) from Appendix
A.
5) Calculate correction factor for Bottom K1 and Top K1.
6) Design for X% flooding at maximum flow rate for top and bottom part of distillation.
7) Calculate the maximum flow rates of liquid.
8) Calculate Net area required.
103
9) Take down comer area as %Y of the total column cross sectional area.
10) Calculate the column diameter.
11) Calculate the column height using the actual number of stage.
12) Calculate column area, down comer area, active area, net area, hole area and
weir
length.
13) Calculate the actual min vapor velocity.
14) Calculate Back-up in down comer.
15) Check residence time.
16) Check entrainment.
17) Calculate number of holes.
18) Calculate area of condenser and re-boiler.
19) Calculate Thickness of the distillation.
104
Distillation Column sample Calculation (T-101)
T-101 column properties:
Top
Bottom
Unit
Vapor rate (Vn)
1268.5000
1461.0000
Mass Density for Vapor ρv
7.6228
6.6793
Molecular Weight (M.Wt)
46.3670
44.1080
Liquid rate (Ln)
1057.0000
3655.4000
kmol/hr
Mass Density for Liquid ρL
733.0000
792.9500
kg/m3
Molecular Weight (M.Wt)
46.3670
36.5240
Surface Tension
0.0213
0.0354
kmol/hr
kg/m3
N/m
Number of Stages:
Applying short cut method for calculating the no. of stages:
Table 3-2 Actual and Theoretical number of stage
Number of stages
Efficiency
Actual number of stages
34
0.75
45.0000
Column diameter:
Liquid vapor flow factor:
105
Mass Density for Vapor
ρv
Mass Density for Liquid
ρL
Top
Bottom
7.6228
6.6793
733.0000
792.9500
0.0213
0.0354
Surface tension
unit
kg/m3
kg/m3
N/m
Bottom = FLV = (L/V)*(ρv/ ρL)0.5 = 0.2296
Top =
FLV = (L/V)*(ρv/ ρL)0.5 = 0.085
Take plate spacing as 0.6 m
Figure (55): Flooding velocity for sieve plates
From the figure above:
Base K1 = 0.08
Top K1 = 0.1
106
Correction for surface tensions
Base K1 = 0.0897
Top K1 = 0.1013
Flooding velocity:
Base = uf = K1((ρL- ρv)/ ρv)0.5 = 0.9729 (m/s)
Top = uf = uf = K1((ρL- ρv)/ ρv)0.5 = 0.9882 (m/s)
Design for 85% flooding at maximum flow rate
Base uv = uf*0.85 = 0.827 (m/s)
Top = uv = uf*0.85 = 0.8399 (m/s)
Maximum volumetric flow rate
Bottom = Vmax= Vn*M.Wt/ρv*3600 = 2.68 (m3/s)
Top = Vmax= Vn*M.Wt/ρv*3600 = 2.1433 (m3/s)
Net area required:
Bottom = A=Vmax/uv = 3.2407 (m2)
Top = A=Vmax/uv = 2.5517 (m2)
Taking downcomer area as 12 per cent of total.
107
Column cross-sectional area
Base =
= 3.2407 /(1 – 0.12 ) = 3.6827 (m2)
Top =
= 2.5517 /( 1 – 0.12 ) = 2.8997 (m2)
Coloumn diameter:
Bottom = D = (Anet *4/π)0.5 = 2.1654 (m)
Top = D = (Anet *4/π)0.5 = 1.9215 (m)
Use same diameter above and below feed
D = 2.1654 (m) = 7.1044 (ft)
Column Height:
Total height = H=(Number of stage * Plate spacing)+Clolumn Diameter
= 22.5654 (m) = 74.0335 (ft)
Maximum volumetric liquid rate = ( LN*M.Wt)/(ρL*3600) = 0.0468 (m3/s)
108
Figure (56):Selection of liquid flow arrangment
From the figure above:
Double pass plate is used
Provisional plate design:
Column diameter = Dc = 2.1654 (m)
column area = (3.14/4)*(Dc^2) = 3.6828 (m2)
Downcomer area Ad = 0.5524 (m2)
Net area = An = Ac – Ad = 3.1304 (m2)
Active area = Aa = Ac - 2*Ad = 2.5779 (m2)
Hole area = Ah = 10% of Aa = 0.2578 (m2)
109
Figure (57): Relation between downcomer are and weir length
From the figure above:
= 15
Lw/Dc = 0.76
Weir Length = lw = 1.6457 (m)
Take weir height = hw = 45 (mm)
Hole diameter (dh) = 4 (mm)
Plate thickness = 5 (mm)
Check weeping:
Maximum liquid rate
110
Lw = (Ln*Mwt)/3600 = 37.0861 (kg/s)
Turndown percentage = 0.80
Minimum liquid rate = Lwd *0.8 = 29.6689 (kg/s)
Maximum = how =750*(Lw/(ρLlw))2/3 = 69.8448 (mm liquid )
Minimum = how =750*(Lw/(ρLlw))2/3 = 60.1904 (mm liquid)
At minimum rate = hw + how = 105.1904 (mm liquid)
Figure (58): Weep point correlation
From the figure above:
K2 = 32
Minimum vapor velocity through hole:
uh (min) = (K2-0.90(25.4-dh))/ρv0.5 = 4.9295 (m/s)
Actual minimum vapor velocity = Minimum vapor rate/Ah = 8.3167 (m/s)
So minimum operating rate will be well above weep point.
111
Plate pressure drop:
Dry plate drop
Maximum vapor velocity through holes (uh) = Bottom Vmax/Hole area Ah = 10.395 (m/s)
Figure (59): Discharge coefficient, sieve plates
From the figure above:
Plate thickness / hole dia. = 1.25
Ah
x100  10
Ap
Co  0.86


112
U
hd  51 h
 Co
hr 



2
12.5 x10 3
L
 V

 L

  462.7743

 15.7639mmliquid
Total plate pressure drop
hb  hw  hdc  ht  how  193.383mmliquid
Down comer liquid back-up:
Downcomer pressure loss
Take hap  hw 10  45 10  35mm
 Area under apron
Aap  weirlengthxhap  0.0576m 2
As this is less than Ad  0.5524m 2 use
Aap
in the next equation for hdc

2
 max .liquid rate 
  1.0944mm  2mm
hdc  166



xA
L
ap



113
Back-up in downcommer
hb  hw  hdc  ht  how  309.3222mm  0.3093(m)
0.3093 < 0.5 (plate spacing + weir height) = 25
So plate spacing is acceptable
Check Residence Time
tr 
hb xAd x L
 4.6535 sec  3 sec satisfactory
Lwd
Check Entrainment
UV 
volumetric flowrate
 0.8561m / s
An
Percent Flooding 
UV
x100%  87.9974%
Uf
FLV ( Bottom)  0.2296
114
Figure (60): Entrainment correlation for sieve plates
From the figure above:
ψ =0.013 , well below 0.1
Perforated area:
115
Figure (61): Relation between angle subtended by chord, chord height and chord length
From the figure above:
at
lw
 0.76
Dc
  95

Angle subtended by the edge of the plate = 85
Mean length, unperforated edge strips =
Area of unperforated edge strips=
3.1383
0.1412 m2
Mean length of calming zone,approx =1.6086 m
Area of calming zones =0.1448 m2
2
Total area for perforations, Ap =2.2919 m
Ah / Ap  0.1125m 2

116
Figure (62): Relation between hole area and pitch
From the figure above:
lp / dh  2.95 satisfactory within 2.5 to 4

Number of holes:
Area of one hole = d h2  0.0001m 2
Number of holes = Aa/0.00001 = 20514.58 hole
117
Area of condenser
Inlet temperature T1
Outlet temperature T2
Mean overall heat transfer coefficient U
Heat flow Q
AC 
92.62
73.263
280
Co
Co
W/m2.Co
9619.444
KW
121.7
Co
124
Co
Q
 1.77363m 2  19.1 ft 2
UT
Area of reboiler
Inlet temperature T1
Outlet temperature T2
Mean overall heat transfer coefficient U
Heat flow Q
Ab 
1000.0000
14130
W/m2.Co
KW
Q
 6.149758m 2  66.1976 ft 2
UT
118
Thickness Calculations:
Internal raduis of shell before allowance corrosion is added ri
= D*39.37/2
42.647
in
Maximum allowable internal pressure P
100.000
psi
Working stress for carbon steel S
13706.660
psi
Efficincy of joients EJ
0.850
Allowance for corrosin Cc
0.125
in
Pri


  CC  0.4929in  12.5208mm
t  
 SEj  0.6 P 
119
Table (23):Specification sheet of Acetaldehyde Column T-101
Equipment Name
Acetaldehyde Column
Objective
Separate Acetaldehyde
Equipment Number
T-101
Designer
Eid Ali
Type
Continuous Tray Distillation Column
Location
After Absorber (T-100)
Material of Construction
Carbon steel
Insulation
Mineral wool
Cost ($)
$711,828
Operating Condition
Key Components
Light
acetaldehyde
Heavy
ethyl acetate
Operating Temperature (oC)
57.7
Operating Pressure (kpa)
100
Feed Flow Rate (kg/h)
78872
Diameter (m)
2.1665
Height (m)
23.1665
Thickness (mm)
12.5208
120
Table(24) : Specification sheet for second distillation column (T-102)
Equipment Name
Distillation column
To separate ethyl acetate from other
Objective
compounds
Equipment Number
T-102
Designer
YOUSEF BAHBAHANI
Type
Tray column
Location
Ethyl acetate Production
Material of Construction
Carbon steel
Insulation
Foam wool
Key Components
Light
Ethyl
acetate
Heavy
Ethanol
Dimensions
2.3
Diameter (m)
18
Height (m)
Number of stages
13
Reflux Ratio
2
Tray Spacing
0.6
Type of tray
Sieve trays
121
Table (25):Specification sheet of Ethyl acetate Column T-103
Equipment Name
Distillation column
Objective
To separate ethyle acetate
Designer
Mosleh mohammed
Type
Tray column
Material of Construction
Carbon steel
Insulation
Minral wool and glass fiber
Key Components
Light
ethyl acetate
Heavy
ethanol
Dimensions
5.6
Diameter (m)
61
Height (m)
Number of Trays
128
Reflux Ratio
1
Tray Spacing
0.6
Type of tray
Sieve trays
122
Table (26):Specification sheet of Ethyl acetate Column T-104
Equipment Name
Distillation column
Objective
To separate ethanol
Designer
Omar al-ajmy
Type
Tray column
Material of Construction
Carbon steel
Insulation
Minral wool and glass fiber
Key Components
Light
ethanol
Heavy
Water
Dimensions
4.1
Diameter (m)
33
Height (m)
Number of Trays
66
Reflux Ratio
1
Tray Spacing
0.6
Type of tray
Sieve trays
123
Table (27):Specification sheet of Ethyl acetate Column T-105
Equipment Name
Distillation column
Objective
To separate ethanol
Designer
Khalid Sulaily
Type
Tray column
Material of Construction
Carbon steel
Insulation
Minral wool and glass fiber
Key Components
Light
Water
Heavy
Acetic acid
Dimensions
4.8
Diameter (m)
43.8
Height (m)
Number of Trays
128
Reflux Ratio
1
Tray Spacing
0.6
Type of tray
Sieve trays
124
Sample calculation for no stages using short cut method on (T-105)
-Assuming plate efficiency = 50%
Q
F (mol/h)
P(kPa)
Comp.
0
1407000
103.4 D
Xf
xf*F
C L
0.00500
DH
0.85000
A.A
0.15000
7035.0
1195950
.0
211050.
0
1404000 W
3000
yd
yd*D xw
7020.
0.00500
0 0.00000
####
0.85000 ###
0.01200
####
0.14000 ###
0.98000
xw*
W
0.0
Comp.
Ethanol
A
8.112
B
1592
C
226.1
H2O
Acetic
Acid
7.966
1668
228
7.387
1533
222..3
Comp.
Vapor
Pressure
36.0
294
0.0
297
6.0
Dew Point of the distillate (Top Temperature
)
Tdp
105 Celsius
Comp.
C L
DH
A.A
KD=
T
Yid
Ki
αi=Ki/KD yi/αi
xi
2.58808 2.21526 0.002 0.00204
0.005
2717
3087
26
5385
1.16829
0.77028
0.85
5871
1
0.85
1082
0.65102 0.55724 0.251 0.22767
0.14
6454
4505
24
3533
1.103
∑(yi/αi)=
49
1.10349
3283
103.360
728
Tdp-T=
Eth.
2007
H2O
Acetic
Acid
906
504.9
125
mmHg
1.639
27
125
Bubble Point of the bottoms
Tbp
120 Celsius
Comp.
C L
DH
A.A
KD
T
αLd
αLw
αL,av
Nm=
Ki
α =Ki/KD α*xi
yi
4.18192 2.17716
0.00000
4487
1278
0 0.00000
1.92081
0.01200
5205
1 0.012 0.02202
1.04442 0.54374 0.532
0.98000
7372
1725
87 0.97798
0.544
∑αXi
87
Comp.
Vapor
Pressure
Eth.
3243
H2O
Acetic
Acid
148
Comp.
Vapor
Pressure
Eth.
2565
H2O
Acetic
Acid
1168
Xiw
1.83531
0639
118.570
2559
Tbp-T
810
mmHg
1.429
74
2.21526
3087
2.17716
1278
2.19612
9553
30.9 theortical stages
Shortcut Method
Tavg
Comp.
C L
DH
A.A
112.5 Celsius
α
=Ki/K
Xif
yid
Ki
c
xiw
3.30738 2.195
0.00500 0.00500
3904
77 0.00000
1.50625
0.85000 0.85000
0927
1 0.01200
0.82896 0.550
0.15000 0.14000
7793
35 0.98000
642.9
126
ɵ
1-q=
2.02469
1
Rm+1=
Rm
R
(N-Nm)/(N+1)=
N=
ɵ must be between 2.17 and 1
3.41
2.41
2.892
assume
R=1.2*Rm
0.52005
2832
65 theortical stages
127
Reactor
We have two reactors in the plant and they are :
Packed Bed Reactors
In a PBR, one or more fluid reagents are pumped through a pipe or tube. The chemical reaction
proceeds as the reagents travel through the PBR. In this type of reactor, the changing reaction
rate creates a gradient with respect to distance traversed; at the inlet to the PBR the rate is very
high, but as the concentrations of the reagents decrease and the concentration of the product(s)
increases the reaction rate slows. Some important aspects of the PFR:



All calculations performed with PFRs assume no upstream or downstream mixing, as
implied by the term "plug flow".
Reagents may be introduced into the PBR at locations in the reactor other than the inlet.
In this way, a higher efficiency may be obtained, or the size and cost of the PBR may be
reduced.
A PBR typically has a higher efficiency than a CSTR of the same volume. That is, given
the same space-time, a reaction will proceed to a higher percentage completion in a PBR
than in a CSTR.
For most chemical reactions, it is impossible for the reaction to proceed to 100% completion.
The rate of reaction decreases as the percent completion increases until the point where the
system reaches dynamic equilibrium (no net reaction, or change in chemical species occurs). The
equilibrium point for most systems is less than 100% complete. For this reason a separation
process, such as distillation, often follows a chemical reactor in order to separate any remaining
reagents or byproducts from the desired product. These reagents may sometimes be reused at the
beginning of the process, such as in the Haber process.
A catalytic fixed bed reactor is a cylindrical tube, randomly filled with catalyst particles, which
may be spheres or cylindrical pellets. The advantages of such structured solid phases are not only
to optimize flow distribution patterns and the reduction of the pressure drop but also to alternate
128
the speed of the reaction. The following picture shows the packed catalyst in a reactor
Figure (63): Fixed-bed Reactorin industry
129
Material of Construction:We chose carbon steel as material of construction in tube and shell sides.
Because by checking in figure 1 and 2 in appendix, the components in tube side are ethanol, air
and very small amount of hydrogen, all these components are suitable with carbon steel and the
small amount of H2 will not produce considerable corrosion. We can use stainless steel but
carbon steel is good and cheaper. And in shell side we have only water, so there is no problem
with carbon steel.
Insulation:Material of insulation depends on the operating temperatures, since higt temperature in the
reactor is so from figure 3 in appendix, we can see that the possible materials that cover the
temperature are glass fiber, calcium silicate, cellular glass, and mineral wool.
And we choosed mineral wool as insulation.
130
131
Sample calculation on the first reactor (RCV-100):
Rate low:
2CO+4H2
==>
CH3CH2OH+H2O
-ra = K*(Ca^2)*(Cb^4)
Stoichiometry:
a/a
b/a
c/a
d/a
1
2
0.5
0.5
ya0 = Fa0/Ft0 = 0.033
 = ∑I = 0.5+0.5-2-1 = -2
Pressure (P) =
Temperature (T0) =
Temperature (T) =
ε = ×yAo = -0.066
11307
598
K
680.9 K
kpa
ΘB = Fbo/Fao = 29.0469279
=0.02752 (kmol/m3)
= 1.915931 (kmol/m3)
132
Weight of the catalyst:
dx/dW = -ra/Fa0
Using polymath simulator to get the weight of the catalyst
we get K from :
04/2003-04-233.pdf
http://www.bjb.dicp.ac.cn/jngc/2003/03-
K = 0.0218
W = 21600 (kg)
And from http://www.patentgenius.com/patent/4376724.html
We get bulk density (catalyst) = 573.3 (kg.m3)
Volume of the reactor:
Assume L = 2D
V = W/bulk density = 37.7 (m3)
Diameter and Length of Reactor :
Assuming length = 2*Diameter
D = (V/3.14)^1/3 = 2.29077 (m)
L = 4.5815 (m)
133
Total height of reactor(with 2 spherical heads)
= H+2(D/2)+.5+.5 =
7.87 (m)
Thickness :
t = (P r i / S E - 0.6P) + Cc =
P :feed pressure (psi)
r i : internal raduis (in)
E : efficincy of joients
S : working stress (psi)
Cc : allowance for corrosin (in)
1.64E+03
45.09384918
0.85
13700
0.125
t = 0.1765466 (m)
CRV-100(heat exchanger portion) :
Heat amount (Q) = 130611.1111 KW (From HYSYS)
By assuming overall heat transfer coefficient from table 1 in appendix for Gases as Hot fluid and
water as cold fluid.
The range from the appendix from : 20 - 300
We take U= 160.45W/m2.oC
Gravitational acceleration = 9.81 m/s2
134
Gases (Tube side)
Parameter
Inlet
Outlet
C
325
408.4
Mass Density ρ
kg/m3
7.0841
6.4486
Specific Heat Cp
kJ/kg.C
9.5
9.5
Mass Flow Rate
kg/s
108
108
Temperature Ti
Unit
o
Cooling water (shell side)
Parameter
Unit
Temperature ti
Inlet
Outlet
o
C
25
280
Specific Heat Cp
KJ/Kg.K
4.2
4.286
Mass Flow Rate
kg/s
47.322
47.322
Mass flow rate is calculated from HYSYS by using heater device with (Q= Q reactor, P=4 bar,
and Tin= 25 oC Tout=200oC, the steam generated in a low pressure steam)
135
Mean Temperature difference:-
T1
Tlm 
R 
T1
 t 2   T2  t1 
 T1  t 2  
ln 
 T  t  

2
1


t 2  t1 
 T2 
;S 
t 2  t1
T1  t1
Tm  Ft Tlm
T2
408.4
o
C
T1
325 oC
Change in the phase
Tw1
25 oC
Tw2
200 oC
<Temperature Profile>
No need to find R & S (the
reason is below)
Ft= 1 (because I have 1
shell & 1 tube)
Q= U.A.∆Tm
A= 130611111.1 /(160.45*230.5)
→A = 3531.522 m2
From table 2 in appendix,
136
Outer diameter o.d = 25 mm = 1 in
Standard :
i.d= 16 mm
L= 4.83 m
tringual Pitch =1.25 * dia.
3.25 mm
Area of one tube = L*Do* π =4.83 *25 *10-3 *π = 0.379 m2
Nt = No. of tubes = Atot /A one tube
= 3531.522 /0.379
→Nt = 9318 tubes
137
Table (28):Reactor (CRV-100) Specification Sheet:
Equipment Name
Packed bed reactor
Objective
To convert syngas to ethanol and side products
Equipment Number
CRV-100
Type
Fixed bed
Location
After the heater (E-101)
Material of Construction
Carbon steel
Insulation
Glass wool
Operating Condition
Operating Temperature (oC)
325
Volume of Reactor (m3)
37.7
Operating Pressure (psia)
1640
Catalyst Type
Rh/Sio2
Feed Flow Rate (kmole/h)
124940
Catalyst Density (Kg/m3)
573.3
Conversion (%)
60
Catalyst Diameter (m)
0.00635
Weight of Catalyst (Kg)
21600
Reactor Height (m)
7.8723
Number of Beds
1
Reactor Diameter (m)
2.29077
insulation cost ($)
111088
Reactor Thickness (m)
0.103248
Cost of reactor ($)
953488
Cost of catalyst ($)
21,089
138
The second Reactor (CRV-101)
To design the Trans esterification Reactor (R-101), Data of Kinetics rate which is available in
different websites .Based in this data ,Volume of reactor that is needed to design can be
estimated .
For reaction:
Ethylacetate
+ H2 O
Ethanol
+ acetic acid
With our design equation with first order reaction :
Dx/dv = k (1-x)/Vo
Where:
K= 0.000958 s-1 =34.5 hr-1
X= 30 %
FAo =191176 kmol/h
Vo = 1093 m3/h
CAo = FAo/ Vo =191176 kmol.h-1/ m3.h-1
The volume of the reactor = 15 m3 ( by poly math programme)
Assumption:
b : bulk density of the catalyst (kg/m3)=1124.11
 : porosity of the catalyst = 0.3
Weight of catalyst:
W V tubes b (1   ) =15* 1124.11(1-0.3) =11016 kg
V =π r2 h
Assume : h/D = 4/1 (from heuristic)
h=4D
V= π (D/2)2 (4D)
V= π D3
139
D=(V/ π)1/3 =(15/ π)1/3 =1.68 m
H=4D =4*1.68=6.73 m
Table (29):Reactor
(CRV-101) specification sheet
Equipment Name PBR
Objective Ethyl acetate production
Equipment Number CRV – 101
Designer Yousef bahbahani
Type
Fixed bed catalytic reactor
Location
Between two mixer (101 &103)
Material of Construction
Carbon steel
Insulation
-----------------------------------------------------------------------Operating Condition
Operating Temperature
(oC)
30.1
Operating Pressure (psia)
15
Feed Flow Rate (kmole/h)
9236.8
Conversion (%)
30
Reactor Height (m) 30
RH OVER
Catalyst Type SILICA
GEL
Catalyst Density (Kg/m3) 1124
Reactor Diameter (m)
1.68
140
Flash Seperator
A vapor-liquid separator is a vertical vessel used in several industrial applications
to separate a vapor-liquid mixture. Gravity causes the liquid to settle to the
bottom of the vessel, where it is withdrawn. The vapor travels upward at a design
velocity which minimizes the entrainment of any liquid droplets in the vapor as it
exits the top of the vessel.
Fig(64):vertical separator
141
The feed to a vapor-liquid separator may also be a liquid that is being partially or
totally flashed into a vapor and liquid as it enters the separator.
A vapor-liquid separator may also be referred to as a flash drum, knock-out drum,
knock-out pot, compressor suction drum or compressor inlet drum.
When used to remove suspended water droplets from streams of air, a vapor-liquid
separator is often called a demister.
Vapor-liquid separators are very widely used in a great many indusries and
applications, such as:
1. Oil refineries
2. Natural gas processing plants
3. Petrochemical and chemical plants
4. Refrigeration systems
5. Air conditioning
6. Compressor systems for air or other gases
7. Gas pipelines
8. Steam condensate flash drums
142
Fig(65): Vertical separator
Material of Construction:-
We can use stainless steel but carbon steel is good and cheaper.
Insulation:Material of insulation depends on the operating temperatures, since temperature in the
seperator is not high so from figure 3 in appendix, we can see that the possible materials that
cover the temperature are glass fiber and mineral wool.
And we choosed mineral wool as insulation.
143
Table (30): Nomenclatures for separator
Symbol
Nomenclature
Mv
Mass flow rate of the vapor (Kg/h)
ML
Mass flow rate of the liquid (Kg/h)
Ρ
Density (Kg/m3 )
P
Inlet pressure (psi)
S
Max. allowable working stress (psi)
Ej
Efficiency of joints expressed as fraction
Cc
Allowance for corrosion
U
Settling velocity (m/s)
Vv
Volumetric flow rate of the vapor (m3/s)
Lv
Volumetric flow rate of the liquid (m3/s)
VHV
Volume held in vessel (m3 )
Dv
Minimum vessel diameter (m)
Hv
Liquid depth (m)
ri
Inside radius of the shell before corrosion (m)
H
Length (m)
Do
Outlet diameter (m)
144
VDv
Volume of cylinder using Dv (m3)
VDo
Volume of cylinder using Do (m3)
Vm
Volume of metal (m3)
Wm
Weight of metal (Kg)
Design Procedures and Equations:
1. Settling velocity
Ut = 0.07 [(ρL – ρv ) / ρv ]0.5 = 0.1526(m/s)
2. Volumetric flow rate
Vv = Mv / (3600 * ρv ) = 0.5832 (m3/s)
Lv = ML / (3600 * ρL ) = 0.02425 (m3/s)
3. Volume held in vessel
VHV = 10 * 60 * Lv = 14.5524 (m3)
4. Minimum vessel diameter
Dv = [(4 * Vv ) / (pi * Us )]0.5 = 2.2 (m) = 86.867 (in)
5. Liquid depth
Hv = VHV / [(pi / 4) * (Dv )2 ] = 3.8 (m)
ri = Dv / 2 = 1.103 (m) = 43.434 (in)
145
Thickness = Cc + [(P * ri ) / (S * Ej – 0.6 * P)] = 6.8 (in) = 0.17288 (m)
h = [3 * (Dv / 2)] + Dv + Hv + 0.4 = 9.724 (m)
6.area of vessel = 2*pi*(dv/2)*ht = 67.3699 (m2)
7. Metal
Vm = VDo - VDv = 11.647 (m3)
Wm = Vm * Density of the steel = 89684.27 (kg)
Cost 20
146
Table (31):specification sheet for separator V-100
Equipment Name
Separator
TO separate h2 from the other
Objective
gases
Equipment Number
V-100
Designer
Eid Ali
Type
Vertical
Location
After HE (E-102)
Material of Construction
Carbon Steel
Insulation
Glass wall and quartz
Cost ($)
$ 86100
Operating Condition
Operating Temperature
o
( C)
60
Operating Pressure (psi)
1640
2.2
Height (m)
9.7
Dimensions
Diameter (m)
147
Absorber
Gas absorption is one of the major mass transfer unit operations used in the separation or
purification of gas mixtures. The operation is carried out by contacting the gas with a liquid
solvent, usually in a packed or plate column. The regenerated solvent is recycled to the
absorption column.
One of the applications of absorption technology is the purification of various process streams to
prevent pollution, corrosion, catalyst poisoning or condensation in subsequent low temperature
treatment. When the two contacting phases (gas and liquid), this operation called absorption. A
solute or several solutes are absorbed from the gas phase into the liquid phase in absorption. This
process involves molecular and turbulent diffusion or mass transfer of solute through a stagnant,
non diffusing gas into a stagnant liquid.
Fig(66) : absorber
148
Plate contactors:Cross-flow plates are the most common type of plate contactor
used in distillation and absorption columns. In a cross-flow plate
the liquid flows across the plate and vapor up through the plate.
There are three principal types of cross-flow tray are used,
classified according to the method used to contact the vapor and
liquid.
a) Sieve plate
Sieve trays are simply metal plates with holes in them.
Vapor passes straight upward through the liquid on the
plate. The arrangement, number and
size
of the holes are design parameters.
Because of their efficiency, wide
operating range, ease of maintenance
and
cost factors, sieve and valve trays
have replaced the once highly thought
of
bubble cap trays in many applications.
b) Bubble-cap plate
A bubble cap tray has riser or chimney fitted over each hole,
and a cap that covers the riser. The cap is mounted so that
there is a space between riser and cap to allow the passage
of vapor. Vapor rises through the chimney and is directed
149
downward by the cap, finally discharging through slots in the
cap, and finally bubbling through the liquid on the tray.
c) Valve plate
In valve trays, perforations are covered by lift able caps.
Vapor flows lifts the caps, thus self creating a flow area for
the passage of vapor. The lifting cap directs the vapor to
flow horizontally into the liquid, us providing better mixing
than is possible in sieve trays.
Liquid and Vapor Flows in a Tray Column
The next few figures show the direction of vapor and liquid flow
across a tray, and across a column.
150
Each tray has two conduits, one on each side, called ‘down
comers’. Liquid falls through the down comers by gravity from
one tray to the one below it. The flow across each plate is shown
in the above diagram on the right.
A weir on the tray ensures that there is always some liquid
(holdup) on the tray and is designed such that the the holdup is
at a suitable height, e.g. such that the bubble caps are covered
by liquid.
Being lighter, vapor flows up the column and is forced to pass
through the liquid, via the openings on each tray. The area
allowed for the passage of vapor on each tray is called the active
tray area.
As the hotter vapor passes through the liquid on the tray above,
it transfers heat to the liquid. In doing so, some of the vapor
151
condenses adding to the liquid on the tray. The condensate,
however, is richer in the less volatile components than is in the
vapor. Additionally, because of the heat input from the vapor, the
liquid on the tray boils, generating more vapors. This vapor,
which moves up to the next tray in the column, is richer in the
more volatile components. This continuous contacting between
vapor and liquid occurs on each tray in the column and brings
about the separation between low boiling point components and
those with higher boiling points.
Tray Designs
A tray essentially acts as a mini-column, each accomplishing a
fraction of the separation task. From this we can deduce that the
more trays there are, the better the degree of separation and
that overall separation efficiency will depend significantly on the
design of the tray.
Trays are designed to maximize vapor-liquid contact by
considering the liquid distribution and the vapor distribution on
the tray. This is because better vapor-liquid contact means better
separation at each tray, translating to better column
performance. Fewer trays will be required to achieve the same
degree of separation. Attendant benefits include less energy
usage and lower construction costs.
152
Packing
There is a clear trend to improve separations by supplementing
the use of trays by additions of packing. Packing are passive
devices that are designed to increase the interfacial area for
vapor-liquid contact. The following pictures show 3 different types
of packing.
These strangely shaped pieces are supposed to impart good
vapor-liquid contact when a particular type is placed together in
numbers, without causing excessive pressure-drop across a
packed section. This is important because a high pressure drop
would mean that more energy is required to drive the vapor up
the distillation column.
153
Selection of solvent:
The essential elements of solvent selection criterion are feed gas
characteristics (composition, pressure, temperature, etc.) and the
treated gas specifications (i.e. the process requirements). These two
elements provide a preliminary evaluation of the solvent working
capacity which may, however, be influenced by several other elements
such as solvent characteristics and operation issues of the separation
process.
154
Assumptions;a. Tray column.
b. plate spacing = 0.8 m
c. sieve plate
d. weir height = 5 mm
e. hole diameter = 50 mm
f. plate thickness = 5 mm
e. efficiency = 75%
g. flooding = 85%
h. turn down = 70%
i. material of absorber carbon steel
155
PROCEDURE
1. From HYSYS we get physical prosperities.
2. Select trial plate spacing.
3. Calculate the column diameter based on flooding
consideration.
4. Calculate the height of the column.
5. Make a trial plate layout: down comer area, active
area, hole area, hole size, weir height.
6. Calculate the weeping rate.
7. Calculate the plate pressure drop.
8. Calculate down comer liquid back-up.
9. Thickness.
10. Weight of the metal
Detailed calculation procedure:
1. the column diameter
Flv 
Lw
Vw
v
l
156
Where,
Lw : liquid mass flow rate (kg/s)
Vw : Vapor mass flow rate (kg/s)
Flv : liquid vapor flow factor
we assumed try spacing
From the figure (A.1 ) in appendix we get K1
Correction for surface tension
0.2
 surfaceTension *1000 
K1  
 K1
20


Where,
K1: correction for surface tension
Flooding vapor velocity
uf  K1
(v  l )
v
Where,
uf : flooding vapor velocity (m/s)
Design for 85%flooding at maximum flow rate
157
ŭf = uf*0.85
Take maximum volumetric flow-rate from HYSYS
V
Anet   max
u
 f max




Where,
Anet : net area required (m2)
Take down comer area as 12 % of total area
A = A net *0.88 (m2)
D  A*

4
Where,
D: column diameter (m)
2. Maximum volumetric liquid rate
Maximum volumetric liquid rate=
LbottomMw
3600 *  l
158
3. Column height
h =(actual number of stages* tray spacing )+Dmax
Where,
h: column height (m)
Actual number of stage = Efficiency * #of stage
4. Provisional plate design
Where,
Dc: column diameter (m)

4
Ac: column area for cylinder = Dc 2 (m2)
An: down comer area = 0.12*Ac (m2)
Aa: active area= Ac-2Ad (m2)
Ah :hole area by taking 10% of Aa
weir length(lw) from figure (A.3 ) in appendix
159
5. Check weeping
Maximum liquid rate= lw*MW (Kg/s)
Minimum liquid rate @ 70% turn-down =0.7*max liquid rate
(Kg/s)
Height of the liquid crest over weir
 L 
how  750 w 
 l lw 
2
3
Where,
how: height of the liquid crest over weir (mm Liquid)
Assuming,
take hole diameter(mm)
plate thickness (mm)
weir height(hw) (mm)
160
at minimum rate hw + how
from figure (A.4)in appendix@ hw + how we get K2
Vapor velocity
uh 
K 2  0.9(25.4  d h )
v
(m/s)
Where,
uh : vapor velocity
K2 : constant
dh : hole diameter (mm)
Actual minimum vapor velocity
Actual minimum vapor velocity = minimum vapor rate / Ah
6. Plate pressure drop
Maximum vapor velocity through holes = Max volumetric flow
rate/Ah
161
From figure (A.5)
For plate thickness/ hole diameter =1, and Ah/Ap = Ah/Aa =0.1
We find Co.
u
hd  51 h
 Co
hr 



2
 v

 l



12.5 * 1000
l
ht = hd +(weir length +how )+hr
Where,
hd: dry plat drop (mm liquid)
hr :residual head (mm liquid)
ht: total pressure drop (mm liquid)
7. Thickness


Pri
  Cc
t 
 ( SE  0.6 P 
j


Where,
162
t: thickness (in)
p: Internal pressure (psig)
ri: Inside radius (in)
S: Working stress (psi)
Ej: Efficiency 0f joint
Cc: Allowance for corrosion (in)
Down comer back up
Take hap (mm) =
hw - 10
Area under upron Aapron (m2) =0.6*hap
As this less than Ad use Aao(m2)
Head loss in the down comer (mm)=
 L
hdc (m )  166 w max
 ( A
 l ap
2




2
Lwd: liquid flow rate in down comer (kg/s)
Am: either Ad , or Aad (the smaller ) (m2)
hb (mm) = hw +how +ht +hdc
163
8. Number of holes

4
Area of on hole (m2) = Dh 2
Number of holes= hole area/area of one hole
9. weight of the metal
di= Internal column diameter (m)
do=di+2t (m)
Volume of cylinder(di) m3= 2h
di
2
Volume of cylinder (do) m3= 2h
do
2
Volume of metal m3= volume of cylinder(do)- volume of
cylinder(di)
Weight (Kg)= volume of metal *7900
164
Table (32):Specification
Sheet for Absorber
Equipment Name
Absorber column
Objective
Recover carbon monoxide
Equipment Number
T-100
Designer
Mosleh mohammed
Type
Tray absorber
After separator
Location
Material of Construction
Carbon steel
Insulation
Foam wool
Operating Condition
Operating Temperature (oC)
60
Feed Flow Rate (Kmole/hr)
200
Operating Pressure (psiG)
1640
liquid Flow Rate (Kg/hr)
1800
Feed Flow Rate (Kmole/h)
2226
Inert Type
Liquid water
Diameter (m)
1.9
Number of Beds
8
Height (m)
8.36
Height of Bed/s (m)
8.36
Thickness (in)
0.125
165
Heat exchanger
Introduction
A heat exchanger is a device designed to transfer heat from one fluid
stream to another without bringing the fluids into direct contact. Heat
exchange equipment comes in a wide variety of forms, with an equal
variety of functions.
Typical examples include:
1) Concentric tube exchangers
2) Shell and tube exchangers
3) Fixed head
4) Floating head
5) Compact heat exchangers
6) Fin-fan exchangers
7) Plate heat exchangers
166
Fig. (67): Shell and Tube Heat Exchangers (a)
167
Fig.(68): The structure of Shell and Tube Heat Exchanger
The process is summarized as the hot solution which flows on one side
of the barrier will transfer its heat to a cold solution flowing on the
other side. Thermal energy only flows from the hotter to the cooler in
an attempt to reach equilibrium. The surface area of a heat exchanger
affects its speed and efficiency: the larger a heat exchangers surface
area, the faster and more efficient the heat transfer. We will focus our
attention on shell and tube heat exchangers; the case we are dealing
with.
In the shell and tube heat exchangers design, one stream passes
through the inside of a set of tubes called tube side. The other stream
passes over the outside of the tubes, called shell side. Heat is
transferred from the hotter stream to the cooler stream through the
tube wall.
168
Design parameter
The critical design factors for a heat exchanger application are: flow
rate, temperature, pressure drop, heat needed to be transferred.
Performance
Heat exchanger performance is affected by: flow rate, tube size and
tube spacing. Therefore maximum performance can be achieved when
the ideal value for each parameters are used.
Shell and tube heat exchanger is being used in the process of hydrogen
production, because it is the most commonly used type of heat transfer
equipment used in the chemical industries due to the large surface area
in small volume that it provides, it can
be constructed from a wide rang of materials and it is easily cleaned
and also because it contains the following:
1) Connections that come in standardized sizes for easy assembly and
feature additional thread and surface protection for clean installation
2) That is made of high quality compressed fibers which lends to
reusability.
3) Gaskets a standard cast-iron or steel head for heavy duty services.
4) Saddle attaches which make for quick and easy mount.
Assumptions:
1) We use shell and tube heat exchanger counter flow because it is
more efficient than the parallel flow.
169
2) The value of the overall heat transfer coefficient was assumed based
on the fluid assigned in both sides.
3) Assume the outer, the inner diameter and the length of the tube.
Applications
Shell and tube heat exchangers are frequently selected for such
applications as:
-Process liquid or gas cooling.
- Process or refrigerant vapor or steam condensing.
- Process liquid, steam or refrigerant evaporation.
170
Nomenclature
Table (33):Nomenclature of Heat exchanger
Symbol
Definition
T1
Inlet shell side fluid temperature (°C)
T2
Outlet shell side fluid temperature(°C)
t1
Inlet tube side fluid temperature (°C)
t2
Outlet tube side fluid temperature (°C)
µ
Fluid viscosity (m N s /m2)
kf
Thermal conductivity ( W/ m °C)
Cp
Mass heat capacity (kJ / Kg °C)
Р
Density of the fluid (Kg/ m3)
Q
Heat load (Kw)
∆Tlm
Log mean temperature difference (°C)
A
Area (m2)
U
Overall heat transfer coefficient (W/m2. °C)
do
Tube outside diameter (mm)
di
Tube inner diameter (mm)
Lt
Tube length
Re
Reynolds number
Pr
Prandtl number
Gs
Mass velocity (m/s)
171
lb
Baffle spacing (m)
T
Shell Thickness
∆Pt
Tube side pressure drop (N/m2)
Np
Number of tube side passes
Ej
Efficiency of joints
S
Working stress (psi)
Cc
Allowance for corrosion (in)
ri
Internal radius of shell
Calculation procedure
a. Define the duty: heat transfer rate, fluid flow rates, temperature.
b. Collect together the fluid physical properties required: density, viscosity,
c. Thermal conductivity.
d. Select a trail value for the overall coefficient, U.
e. Calculate the mean temperature difference, ΔTm.
f.
Calculate the area required from Q=UAΔTm.
g. Calculate the bundle and shell diameter
h. Calculate the individual coefficients.
i.
Calculate the overall coefficient and compare with the trail value.
j.
Calculate the exchanger pressure drop.
k. Calculate thickness of the shell.
l.
Find the price of the heat exchanger based on the heat transfer area and the material of
construction
172
Detailed calculation procedure
1- Heat load
Q = (m Cp ΔT) hot = (m Cp ΔT) cold, (kW)
2-Tube side flow
mcold 
Qhot
, (Kg/hr)
C p Tcold
3- Log mean temperature
Tlm 
T2  T1
 T 
LN  2 
 T1 
, (°C)
T1  T1  t 2
T2  T2  t1
Where,
T1: is inlet shell side fluid temperature (°C)
173
T2: is outlet shell side fluid temperature (°C)
t1: is inlet tube side temperature (°C)
t2: is outlet tube side temperature (°C)
3-Calculate the mean (true) temperature ∆Tm
ΔTm= Ft * ΔTlm
For more than one tube passes
 (1  S ) 

( R 2  1) LN 
(1  RS ) 

Ft 
 2  S ( R  1  ( R 2  1) 

( R  1) LN 
 2  S ( R  1 ( R 2  1) 


R
(T1  T2 )
(t 2  t1 )
S
(t 2  t1 )
(T1  t1 )
Where,
Ft: is the temperature correction factor
R: is the shell side flow *specific heat / tube side flow*specific heat,
174
(Dimensionless).
S: is temperature efficiency of the heat exchanger, (dimensionless)
4- Provisional Area
A
Q
UTm
, (m2)
Where,
Area of one tube = Lt * do *π , (mm2)
Outer diameter (do), (mm)
Length of tube (Lt), (mm)
Number of tubes = provisional area / area of one tube
5- Bundle diameter
N 
Db  d o  t 
 K1 
1 / n1
, (mm)
175
Where,
Db: bundle diameter, (mm)
Nt: number of tubes
K1, n1: constants.
6- Shell diameter
Ds = Db + (Bundle diameter clearance) , (mm)
Using split-ring floating head type (bundle).
From figure (A.12) we get bundle diameter clearance.
7-Tube side Coefficient
Cold stream mean temperature=
Tube cross sectional area =

4
t 2  t1
, (°C)
2
2
d i , (mm2)
Tubes per pass = no. of tubes / number of passes
Total flow area = tubes per pass * cross sectional area, (m2)
176
Mass velocity = mass flow rate / total flow area, (kg /sec.m2)
Linear velocity (ų) = mass velocity / density, (m/s)
Reynolds number (Re) =ρ ų di / μ
Prandtl number (Pr) = Cp μ / κ
(hi di / κ) = jh Re Pr0.33 * (μ/μwall)0.14
Using Fig.(A.13) to find jh
8-Shell side Coefficient
Baffle spacing (Lb) = 0.2 * Ds, (mm)
Tube pitch (pt) = 1.25 * do, (mm)
Cross flow area (As) = (pt - do)* Ds* Lb / pt , (m2)
Mass velocity (Gs) = mass flow rate / cross flow area, (kg/s.m2)
177
Equivalent diameter for triangular arrangement (de) =1.1*(pt2-0.917do2) /do, (mm)
Mean shell side temperature = (Thi +Tho)/2, (°C)
Reynolds number (Re) = Gs de / μ
Prandtl number (Pr) = Cp μ / κ
And from fig. (A.15) @ Re we find jh.
hs = K * jh *Re *Pr (1/3) / de , W/m2.°C
Overall heat transfer coefficient
d 
d o LN  o 
 1  1
1
 di   d o

  

2K w
di
 U o  ho hod
 1

 hid
 do
 
 di
1
 
 hi 
,(W/m2.°C)
178
9- Pressure drop
Tube side

 L / di
Pt  N p 8 j f 
 M /Mw

 u 2

  2.5  , (KPa)

 2 
Where,
ΔPt: tube side pressure drop (N/m2= pa)
Np : number of tube side passes
u : tube side velocity (m/s)
L: length of one tube, (m)
Use the fig.(A.14)
Shell side
Linear velocity = Gs /р
D
p s  8 j f  s
 do
 L  u 2
 
 l b  2
 M

 M w



0.14
Where,
L: tube length, (m)
179
lb: baffle spacing(m)
Use fig.(12.30) to get jf.
10-Shell thickness
t
Pri
 Cc
SE j  0.6 P
t: shell thickness (in)
P : internal pressure (psig)
ri: internal radius of shell (in)
EJ: efficiency of joints
S : working stress (psi)
Cc: allowance for corrosion (in)
180
Sample Calculation :
Heat exchanger
Shell side
Prameter
Unit
Inlet
Outlet
Mean
Tempreture Ti
C
75
311
193.3
Thermal Conductivty k
W/m.C
1.82E-2
2.66E-1
0.2239
Mass Density ρ
kg/m3
0.11502
6.87E-1
0.0918
Viscosity μ
mPa.s
1.01E-02
1.49E-02
0.0125
Specfic Heat Cp
KJ/Kg.K
28.806
29.607
29.2065
Mass Flow Rate
kg/s
22.22
Prameter
Unit
Inlet
Outlet
Mean
Temperture ti
C
350
322
336
Thermal Conductvity
W/m.C
6.47E-02
8.46E-02
0.074628
Mass Density
kg/m3
0.61124
0.42679
0.519015
Viscosity
mPa.s
1.91E-02
2.55E-02
0.022262
Specfic Heat Cp
KJ/Kg.K
1.5122
1.5598
1.536
Mass Flow Rate
kg/s
79
Tube side
Q = (m Cp ΔT) hot =35080.6 KW
181
T1
C
350
T2
C
309.95
t1
C
134.81
t2
C
311.11
Tlm 
T2  T1
 T 
LN  2 
 T1 
T lm=(350-311.11)-(309.95-134.81) / LN((350-311.11)/(309.95-134))
= 112.465°C
Using one shell pass and two tube passes
R
(T1  T2 )
(t 2  t1 )
182
R= 8.401
S
(t 2  t1 )
(T1  t1 )
S= 0.10209
Using fig. (A.11) to find Ft
Ft=1
Tm  Ft * Tlm
= 112.46°C
From table in appendix assume U=3500 W/m2°C
Provisional area
A
Q
UTm
= 48.0490m2
183
Choose,
Do= 10 mm
Di = 10 mm
Assume,
Lt= 4.25m
Area of one tube = Lt * do *π*0.25 = 0.0333 m2
Number of tubes Nt = provisional area / area of one tube=1439.48tube
As the shell – side fluid is relatively clean use 1.25 triangular pitch.
Using Table (A.4) in appendix
N 
Bundle diameter Db= d o  t 
 K1 
1 / n1
K1=0.175
N1=2.675
Db=290.81mm
184
Use a split – ring floating head type.
From figure (A.12) in appendix
Bundle diametrical clearance = 75 mm
Shell diameter, Ds = Db + bundle diametrical clearance
Ds=365.18mm
Tube – side coefficient
AreaOfOneT ube  0.25 *  * d o  L
2
totalArea
areaOfOneT ube
# tubes
Tubes / Pass 
AssumedPasses
2
cross  Section  area  0.25d i
# tubes 
Area / pass  tubes / Pass cross  sec ton  area 
FlowRate
velocityut  
 Area / Pass * Density
185
Tube cross sectional area = 7.85E-5m2
Tubes per pass = 293.91
Total flow area(area/pass) = tube per pass * cross sectional area
=0.0188m2
Linear velocity (ut) = mass velocity/density = 8077.978m/s
The coefficient can be calculated from the following equation
Re 
cp
ut d i
; Pr 

k
Nu  jh Re Pr 0.33   
 w 
 kf
hi  Nu
 di
0.14
; jh  f (
L
)
di



186
Re=1883.2953
Pr=0.458198
Assume that the viscosity of the fluid is the same as at the wall

1
w
From figure (A.13) in appendix
jh= 2.5E-03

hi  20372.360(W / m 2 C )
Shell - side coefficient
Choose baffle spacing Lb=27.955
Tube pitch (pt)=1.25*do=1.25*30=37.5 mm
 ( pt  d o ) * Ds * Lb  (37.5E  3  10) * 551.9800 * 27.955
 
 0.00133m 2
pt
37.5


Cross-flow area 


 1.1  2
1.1
 pt  0.917d o 2    (37.5) 2  0.917 * (30) 2  0.00710mm
 30 
 do 
Equivalent diameter de = 


187
Re  9432643.6
pr  0.08574
Choose 25 per cent baffle cut.
From figure (A.15) in appendix
jh=0.3
hs = 36596436.76W/m2.C
Overall heat transfer coefficient
Take the fouling coefficient from Table in appendix
Outside coefficient (fouling factor) (hod) 5000
Inside coefficient (fouling factor) (hid) =5000
d
d o LN  o
 1  1  1 
 di

     
 
2k w
 U o   ho   hod 


   d o
d
 i
 1

 hid
 do
 
 di
1

 hi



188
Uo= 331.3700W/m2 °C)
Pressure drop:
Tube side
From figure (12.24)and for Re =1883.295
jf= 1E-3
assume viscosity=0.89

 u 2
 L / di 


pt  N p 8 j f 
  2.5 2

/

w 






pt  8329.976bar
Shell side
From figure (A.16) in appendix and for Re = 212485.79
jf=5.8E-2
Neglecting the viscosity correction term
D
Pt  8 j f  s
 de
 Lt

 l b
 u 2

 2
 

  w



0.14
189
Pt  1044812bar
Shell thickness
P=398.4 kpa
ri = 0.182 m
S= 94432.14 kpa
EJ =0.86
Cc = 0.125 in
In our plant we use shell and tube heat exchanger which is almost the best kind of heat
exchangers because its design has high heat transfer ability. The material of tube used
is carbon steel because it has many advantages such as: Low cost, easy to fabricate,
abundant, most common material and resists most alkaline environments well. The
insulator used is glass wool because it is thermal and fire resistance, lightness, easy
insulation and environmentally friendly.
190
Table (34):Specification sheet for heat exchanger ( E-101)
Equipment Name
Heat exchanger
Objective
increase temperature of syngas
before entering the reactor
Equipment Number
E-100
Designer
Khalid Sulaily
Type
Shell and tube heat exchanger
Location
Before the first reactor
Utility
hot water
Material of Construction
Carbon steel
Insulation
glass wool
Operating Condition
Shell Side
388.5
Inlet temperature (oC)
400
Outlet temperature (oC)
Tube Side
Inlet temperature (oC)
311.1
Outlet temperature (oC)
325.5
Number of Tube Per Pass
55
Number of Tubes
1.71
Shell Diameter (m)
0..3
Heat Exchanger Area (m2)
44.3
Tube bundle Diameter (m) 0.5.5
U (W/C.m2)
..1
191
Table (34):Specification sheet for heat exchanger ( E-101)
Equipment Name
Heat exchanger
Objective
increase temperature of syngas
before entering the reactor
Equipment Number
E-101
Designer
Omar alajmi
Type
Shell and tube heat exchanger
Location
Before the first reactor
Utility
hot water
Material of Construction
Carbon steel
Insulation
glass wool
Operating Condition
Shell Side
Inlet temperature (oC)
75.75
Outlet temperature (oC)
311
Tube Side
Inlet temperature (oC)
350
Outlet temperature (oC)
322
Number of Tube Per Pass
239.91
Number of Tubes
1439.4807
Tube bundle Diameter (m)
0.47
Shell Diameter (m)
0.3658
U (W/C.m2)
330
Heat Exchanger Area (m2)
48.0490
192
Table (35):Specification sheet for heat exchanger ( E-102)
Equipment Name
Cooler
Objective
To decrease the temperature
Equipment Number
E-102
Designer
Mosleh mohammed
Type
Shell and tube
Utility
Cold water
Material of Construction
Carbon steel
Operating Condition
Shell Side
Inlet temperature (oC)
25
Outlet temperature (oC)
48.3
Inlet temperature (oC)
407
Outlet temperature (oC)
60
U (W/m2 oC)
1000
Heat Exchanger Area (m2)
Tube Side
2680
193
Compressor
A gas compressor is a mechanical device that increases the pressure of a
gas by reducing its volume. Compression of a gas naturally increases its
temperature.
Compressors are similar to pumps: both increase the pressure on a fluid
and both can transport the fluid through a pipe. As gases are compressible,
the compressor also reduces the volume of a gas. Liquids are relatively
incompressible, so the main action of a pump is to transport liquids.
Types of compressors
The main types of gas compressors are illustrated and discussed below:
194
Fig(69):compressors types
Centrifugal compressors
Fig(70): centrifugal compressor
A single stage centrifugal compressor
Centrifugal compressors use a vaned rotating disk or impeller in a
shaped housing to force the gas to the rim of the impeller, increasing the
velocity of the gas. A diffuser (divergent duct) section converts the velocity
energy to pressure energy. They are primarily used for continuous,
stationary service in industries such as oil refineries, chemical and
petrochemical plants and natural gas processing plants. Their application
can be from 100 hp (75 kW) to thousands of horsepower. With multiple
staging, they can achieve extremely high output pressures greater than
10,000 psi (69 MPa).
195
Many large snow-making operations (like ski resorts) use this type of
compressor. They are also used in internal combustion engines as
superchargers and turbochargers. Centrifugal compressors are
used in small gas turbine engines or as the final compression stage of
medium sized gas turbines.
Diagonal or mixed-flow compressors
Diagonal or mixed-flow compressors are similar to centrifugal
compressors, but have a radial and axial velocity component at the exit
from the rotor. The diffuser is often used to turn diagonal flow to the axial
direction. The diagonal compressor has a lower diameter diffuser than the
equivalent centrifugal compressor.
Axial-flow compressors
Axial-flow compressors use a series of fan-like rotating rotor blades to
progressively compress the gassflow. Stationary stator vanes, located
downstream of each rotor, redirect the flow onto the next set of rotor
blades. The area of the gas passage diminishes through the compressor to
maintain a roughly constant axial Mach number. Axial-flow compressors
are normally used in high flow applications, such as medium to large gas
turbine engines. They
196
are almost always multi-staged. Beyond about 4:1 design pressure ratio,
variable geometry is often used to improve operation.
Reciprocating compressors
A motor-driven six-cylinder reciprocating compressor that can
operate with two, four or six cylinders.
Reciprocating compressors use pistons driven by a crankshaft. They can
be either stationary or portable, can be single or multi-staged, and can be
driven by electric motors or internal combustion engines. Small
reciprocating compressors from 5 to 30 horsepower (hp) are commonly
seen in automotive applications and are typically for intermittent duty.
Larger reciprocating compressors up to 1000 hp are still commonly found in
large industrial applications, but their numbers are declining as they are
replaced by various other types of compressors. Discharge pressures can
range from low pressure to very high pressure (>5000 psi or 35 MPa). In
certain applications, such as air compression, multi-stage double-acing
compressors are said to be the most efficient compressors available, and
are typically larger, noisier, and more costly than comparable rotary units.
197
Design Procedure:
1. Get the value of n (compression factor) from the following equation:
P1  T1 
 
P2  T 2 
 n 


 n 1 
where P1 = inlet pressure (psi)
P2 = outlet pressure (psi)
T1 = inlet Temperature (R)
T2 = outlet Temperature (R)
n = compression factor
2. Get the value of work done (W):
W 
nR (T1 T 2 )
1 n
where R= Cp / Cv
198
3. Get the value of Hp (Horse Power) :
Hp = W* M
Where M = molar flow rate (lbmole/s)
4.Get the efficiency of the compressor :
Ep 
n
n 1
K
K 1
where K= (Mw*Cp)/(Mw*Cp-1.986)
Cp=heat capacity, Btu/lboF
Sample Calculations on (K-100)
P1 (psi)
P2 (psi)
)T1) (R)
300
1037.6
559.6704
199
T2 (R)
R = (Cp/Cv)
M (lbmole/s)
Cp (Btu/lb. °F)
Mwt
879.75
1.4018
2.46E2
0.58831
11.647
1. ln (P1/P2) = ln (300/1073.6)= -1.24088315
ln (T1/T2) = ln ( 559.67/879.75) = -0.452289737
n/(n-1) = ln(P1/P2) / ln(T1/T2) = 0
n = 1.5735398
2.
W 
nR (T1 T 2 )
1 n
w = (1.5735398*1.4018*(559.6704-879.75))/(1-1.5735398)
=1231.00044(Btu/lbmol)
200
3. Hp = W*M =1231.00044*1.86091667 = 3030.04
4.
Ep 
n
n 1
K
K 1
k = (Mw*Cp)/(Mw*Cp-1.986)
= (11.647*0.58831)/(11.647*0.58831 – 1.986) = 1.408134
Ep = (1.5735398/ (1.5735398-1)) * (1.408134-1)/( 1.408134)
*100=79.519400 %
201
Table (37):Specification sheet for Air compressor( K-100)
Equipment Name
Objective
Equipment Number
Designer
Type
Compressor
To increase the pressure
K-100
Omar ali
Reciprocating Compressor
Material of Construction
Carbon steel
Insulation
Quartz wool
Cost
$ 119,100
Operating Condition
Inlet Temperature
(R)
Inlet Pressure (psia)
559.6704
300
Outlet Temperature
(R)
Outlet Pressure (psia)
879.75
1037.6
79.519400
Efficiency (%)
Power (Hp)
3030.304
%
202
Table (38):Specification sheet for Air compressor( K-101)
Equipment Name
Objective
Equipment Number
Designer
Type
Compressor
To increase the pressure
K-100
KhalidSulaily
Reciprocating Compressor
Material of Construction
Carbon steel
Insulation
Quartz wool
Cost
$ 119,100
Operating Condition
Inlet Temperature
(R)
Inlet Pressure (psia)
Efficiency (%)
066
14.5
2.9 %
Outlet Temperature
(R)
Outlet Pressure (psia)
Power (Hp)
016
15.4
5238.5873
203
CH 4
Hazop , Safety and
Environmental Issues
Introduction to safety:
204
Industrial safety is primarily a management activity which is concerned with reducing,
controlling and eliminating hazards from the industries or industrial units, the danger of life of
human being is increasing with advancement of scientific development in different fields, the
importance of industrial safety was realized because every millions of industrial accidents occur
which result in either death or in temporary disablement or permanent disablement of employees
and involve large amount of losses resulting from danger to property, wasted man hours and
wasted hours.
Process safety has been a primary concern of the process industries for decades. Safety is the
prevention of accident and hazard its important because:
1- Safety protects workers, employers and all people in the plant including strangers from illness,
injuries or death.
2- Ensuring survival of company’s business.
3- It prevents company’s property and facility from damage.
4- It enhances company’s reputation.
5- Safety teaches everyone in the plant to pay attention to their work places and surrounding.
6- Safety can prevent production process interruption and shut down. safety issues have received
increased attention for several reasons that include increased public awareness of potential risks,
stricter legal requirements, and the increased complexity of modern industrial plants.
A successful safety program should have the following:
1. System:
The program needs a system to record what need to be done and to record that the required task
205
2. Training :
The participant must have a positive attitude and understand the fundamentals of chemical
process safety in the design.
3. Providing protective equipment for employee.
4. Safety sign and material safety data sheet must be provided.
5. Emergency response.
6. Hazard analysis and accident investigation
Potential Health Effects of Carbon Monoxide:
Carbon monoxide is an odorless, colorless and toxic gas. Because it is impossible to see, taste or
smell the toxic fumes, CO can kill you before you are aware it is in your home. At lower levels
of exposure, CO causes mild effects that are often mistaken for the flu. These symptoms include
headaches, dizziness, disorientation, nausea and fatigue. The effects of CO exposure can vary
greatly from person to person depending on age, overall health and the concentration and length
of exposure, at low concentrations, fatigue in healthy people and chest pain in people within
heart disease at higher concentrations, impaired vision and coordination; headaches; dizziness;
confusion; nausea can cause flu-like symptoms that clear up after leaving home fatal at very high
concentrations. Acute effects are due to the formation of carboxyhemoglobin in the blood, which
inhibits oxygen intake. At moderate concentrations, angina, impaired vision, and reduced brain
function may result. At higher concentrations, CO exposure can be fatal.
Potential Health Effects of Hydrogen:
Hydrogen is the most flammable of all the known substances. . It is slightly more soluble in
organic solvents than in water. Many metals absorb hydrogen. Hydrogen absorption by steel can
result in brittle steel, which leads to faults in the chemical process equipments. As hydrogen is
extremely flammable, its many reactions may cause fire or explosion. As the gas mixes well with
air, explosive mixtures are easily formed. Moreover the gas is lighter than air. The gas can be
absorbed into the body by inhalation and high concentrations can cause an oxygen-deficient
environment. Individuals breathing such an atmosphere may experience symptoms which
include headaches, ringing in ears, dizziness, drowsiness, unconsciousness, nausea, vomiting and
depression of all the senses. The skin of a victim may have a blue color. Under some
circumstances, death may occur. Hydrogen is not expected to cause mutagenicity,
embryotoxicity, teratogenicity or reproductive toxicity. Pre-existing respiratory conditions may
206
be aggravated by overexposure to hydrogen. When inhaled a harmful concentration of this gas in
the air will be reached very quickly.
Side products:
We have acetaldehyde as side product with large quantity = 7388.2 (kg/h)
So we should know the effects of this component:
Physical Description
Colorless liquid or gas (above 69°F) with a pungent, fruity odor.
OSHA PEL
†: TWA 200 ppm (360 mg/m3)
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, nose, throat; eye, skin burns; dermatitis; conjunctivitis; cough; central nervous
system depression; delayed pulmonary edema; in animals: kidney, reproductive, teratogenic
effects; [potential occupational carcinogen]
Target Organs
Eyes, skin, respiratory system, kidneys, central nervous system, reproductive system
- More information about the main product ethanol:
Appearance: colorless clear liquid. Flash Point: 16.6 deg C. Flammable liquid and vapor. May
cause central nervous system depression. Causes severe eye irritation. Causes respiratory tract
irritation. Causes moderate skin irritation.
This substance has caused adverse reproductive and fetal effects in humans. Warning! May
cause liver, kidney and heart damage.
Target Organs: Kidneys, heart, central nervous system, liver.
207
Potential Health Effects
Eye: Causes severe eye irritation. May cause painful sensitization to light. May cause chemical
conjunctivitis and corneal damage.
Skin: Causes moderate skin irritation. May cause cyanosis of the extremities.
Ingestion: May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May cause
systemic toxicity with acidosis. May cause central nervous system depression, characterized by
excitement, followed by headache, dizziness, drowsiness, and nausea. Advanced stages may
cause collapse, unconsciousness, coma and possible death due to respiratory failure.
Inhalation: Inhalation of high concentrations may cause central nervous system effects
characterized by nausea,
headache, dizziness, unconsciousness and coma. Causes respiratory tract irritation. May cause
narcotic effects in high concentration. Vapors may cause dizziness or suffocation.
Chronic: May cause reproductive and fetal effects. Laboratory experiments have resulted in
mutagenic effects. Animal studies have reported the development of tumors. Prolonged exposure
may cause liver, kidney, and heart damage.
208
HAZOP
Introduction
A Hazard and Operability (HAZOP) study is a structured and systematic examination of a
planned or existing process or operation in order to identify and evaluate potential hazards and
operability problems, or to ensure the ability of equipments in accordance with the design intent,
the HAZOP analysis technique uses a systematic process to identify possible deviations from
normal operations and ensure that appropriate safeguards are in place to help prevent accidents.
It uses special adjectives combined with process conditions to systematically consider all
credible deviations from normal conditions, the adjectives, called guide words, are a unique
feature of HAZOP analysis.
A HAZOP study may also be conducted on an existing facility to identify modifications that
should be implemented to reduce risk and operability problems.
HAZOP studies may also be used more extensively, including:
1- At the initial concept stage when design drawings are available.
2- When the final piping and instrumentation diagrams (P&ID) are available.
3- During construction and installation to ensure that recommendations are implemented.
4- During commissioning.
5- During operation to ensure that plant emergency and operating procedures are regularly
reviewed and updated as required.
HAZOP procedure:
a) Divide the system into sections (i.e., reactor, storage).
b) Choose a study node (i.e., line, vessel, pump, operating instruction).
c) Describe the design intent.
d) Select a process parameter.
e) Apply a guide-word.
209
f) Determine cause(s).
g) Evaluate consequences/problems.
h) Recommend action: What? When? Who?
i) Record information.
j) Repeat procedure (from step 2) .
HAZOP Studies:
HAZOP studies are applied during:
a) Normal operation
b) Foreseeable changes in operation, e.g. upgrading, reduced output, plant start-up and shutdown
c) Suitability of plant materials, equipment and instrumentation
d) Provision for failure of plant services, e. g . steam, electricity, cooling water
e) Provision for maintenance.
Strength of HAZOP:
a) HAZOP is a systematic, reasonably comprehensive and flexible.
b) It is suitable mainly for team use whereby it is possible to incorporate the general experience
available.
c) It gives good identification of cause and excellent identification of critical deviations.
d) The use of keywords is effective and the whole group is able to participate.
e) HAZOP is an excellent well-proven method for studying large plant in a specific manner.
f) HAZOP identifies virtually all significant deviations on the plant; all major accidents should
be identified but not necessarily their causes.
210
Limitation of the HAZOP technique:
a) Requires a well-defined system or activity:
The HAZOP process is a rigorous analysis tool that systematically analyzes each part of a system
or activity. To apply the HAZOP guide words effectively and to address the potential accidents
that can result from the guide word deviations, the analysis team must have access to detailed
design and operational information. The process systematically identifies specific engineered
safeguards (e.g., instrumentation, alarms, and interlocks) that are defined on detailed engineering
drawings.
b) Time consuming:
The HAZOP process systematically reviews credible deviations, identifies potential accidents
that can result from the deviations, investigates engineering and administrative controls to
protect against the deviations, and generates recommendations for system improvements. This
detailed analysis process requires a substantial commitment of time from both the analysis
facilitator and other subject matter experts, such as crew members, engineering personnel,
equipment vendors, etc.
c) Focuses on one-event causes of deviations:
The HAZOP process focuses on identifying single failures that can result in accidents of interest.
If the objective of the analysis is to identify all combinations of events that can lead to accidents
of interest, more detailed techniques should be used.
211
In the fifth distillation we separated acetic acid from waste water which has to
be treated.
Waste Water Treatment
Waste waters can be contaminated by feed-stock materials, by-products, product
material in soluble or particulate form, washing and cleaning agents, solvents and
added value products such as plasticisers.
Treatment of industrial wastewater:
Solids removal
Most solids can be removed using simple sedimentation techniques with the solids
recovered as slurry or sludge. Very fine solids and solids with densities close to the
density of water pose special problems. In such case filtration or ultrafiltration may be
required. Although, flocculation may be used, using alum salts or the addition of
polyelectrolytes.
Oils and grease removal
Many oils can be recovered from open water surfaces by skimming devices. Considered
a dependable and cheap way to remove oil, grease and other hydrocarbons from water,
oil skimmers can sometimes achieve the desired level of water purity. At other times,
skimming is also a cost-efficient method to remove most of the oil before using
membrane filters and chemical processes. Skimmers will prevent filters from blinding
prematurely and keep chemical costs down because there is less oil to process.
Because grease skimming involves higher viscosity hydrocarbons, skimmers must be
equipped with heaters powerful enough to keep grease fluid for discharge. If floating
grease forms into solid clumps or mats, a spray bar, aerator or mechanical apparatus
can be used to facilitate removal. However, hydraulic oils and the majority of oils that
have degraded to any extent will also have a soluble or emulsified component that will
require further treatment to eliminate. Dissolving or emulsifying oil using surfactants or
solvents usually exacerbates the problem rather than solving it, producing wastewater
that is more difficult to treat.
The wastewaters from large-scale industries such as oil refineries, petrochemical plants,
chemical plants, and natural gas processing plants commonly contain gross amounts of
oil and suspended solids. Those industries use a device known as an API oil-water
separator which is designed to separate the oil and suspended solids from their
wastewater effluents. The name is derived from the fact that such separators are
designed according to standards published by the American Petroleum Institute (API).
The API separator is a gravity separation device designed by using Stokes Law to
define the rise velocity of oil droplets based on their density and size. The design is
based on the specific gravity difference between the oil and the wastewater because
212
that difference is much smaller than the specific gravity difference between the
suspended solids and water. The suspended solids settles to the bottom of the
separator as a sediment layer, the oil rises to top of the separator and the cleansed
wastewater is the middle layer between the oil layer and the solids.
Typically, the oil layer is skimmed off and subsequently re-processed or disposed of,
and the bottom sediment layer is removed by a chain and flight scraper (or similar
device) and a sludge pump. The water layer is sent to further treatment consisting
usually of a Electroflotation module for additional removal of any residual oil and then to
some type of biological treatment unit for removal of undesirable dissolved chemical
compounds.
Parallel plate separators are similar to API separators but they include tilted parallel
plate assemblies (also known as parallel packs). The parallel plates provide more
surface for suspended oil droplets to coalesce into larger globules. Such separators still
depend upon the specific gravity between the suspended oil and the water. However,
the parallel plates enhance the degree of oil-water separation. The result is that a
parallel plate separator requires significantly less space than a conventional API
separator to achieve the same degree of separation.
Removal of biodegradable organics
Biodegradable organic material of plant or animal origin is usually possible to treat using
extended conventional wastewater treatment processes such as activated sludge or
trickling filter. Problems can arise if the wastewater is excessively diluted with washing
water or is highly concentrated such as neat blood or milk. The presence of cleaning
agents, disinfectants, pesticides, or antibiotics can have detrimental impacts on
treatment processes.
Activated sludge is a biochemical process for treating sewage and industrial wastewater
that uses air (or oxygen) and microorganisms to biologically oxidize organic pollutants,
producing a waste sludge (or floc) containing the oxidized material. In general, an
activated sludge process includes:
- An aeration tank where air (or oxygen) is injected and thoroughly mixed into the
wastewater.
- A settling tank (usually referred to as a "clarifier" or "settler") to allow the waste sludge
to settle. Part of the waste sludge is recycled to the aeration tank and the remaining
waste sludge is removed for further treatment and ultimate disposal.
A trickling filter consists of a bed of rocks, gravel, slag, peat moss, or plastic media over
which wastewater flows downward and contacts a layer (or film) of microbial slime
covering the bed media. Aerobic conditions are maintained by forced air flowing through
the bed or by natural convection of air. The process involves adsorption of organic
compounds in the wastewater by the microbial slime layer, diffusion of air into the slime
213
layer to provide the oxygen required for the biochemical oxidation of the organic
compounds. The end products include carbon dioxide gas, water and other products of
the oxidation. As the slime layer thickens, it becomes difficult for the air to penetrate the
layer and an inner anaerobic layer is formed.
The components of a complete trickling filter system are fundamental components:
- A bed of filter medium upon which a layer of microbial slime is promoted and
developed.
- An enclosure or a container which houses the bed of filter medium.
- A system for distributing the flow of wastewater over the filter medium.
- A system for removing and disposing of any sludge from the treated effluent.
The treatment of sewage or other wastewater with trickling filters is among the oldest
and most well characterized treatment technologies. A trickling filter is also often called
a trickle filter, trickling biofilter, biofilter, biological filter or biological trickling filter.
Treatment of other organics
Synthetic organic materials including solvents, paints, pharmaceuticals, pesticides,
coking products and so forth can be very difficult to treat. Treatment methods are often
specific to the material being treated. Methods include Advanced Oxidation Processing,
distillation, adsorption, vitrification, incineration, chemical immobilisation or landfill
disposal. Some materials such as some detergents may be capable of biological
degradation and in such cases, a modified form of wastewater treatment can be used.
Spent catalyst treatments:
Disposal of spent catalyst is a problem as it falls under the category of hazardous
industrial waste. The recovery of metals from these catalysts is an important economic
aspect as most of these catalysts are supported, usually on alumina/silica with varying
percent of metal: metal concentration could vary from 2.5 to 20%. Metals like Ni, Mo,
Co, Rh, Pt, Pd, etc., are widely used as a catalyst in chemical and petrochemical
industries and fertilizer industries. They are generally supported on porous materials like
alumina and silica through precipitation or impregnation processes. Many workers have
adapted pyrometallurgy and Hydrometallurgy process for recovery of precious metals.
Many workers have studied the recovery of nickel from a spent catalyst in an ammonia
plant by leaching it in sulphuric acid solution (Hydrometallurgy). Ninety-nine percent of
the nickel was recovered as nickel sulphate when the catalyst, having a particle size of
0.09mm was dissolved in an 80% sulphuric acid solution for 50min in at 70°C. Many
researcher have studied the extraction of metals from spent catalyst by roasting-
214
extraction method (Pyrometallurgy). Chelating agents are the most effective extractants,
which can be introduced in the soil washing fluid to enhance heavy metal extraction
from contaminated soils. The advantages of chelating agents in soil cleanup include
high efficiency of metal extraction, high thermodynamic stabilities of the metal
complexes formed, good solubilities of the metal complexes, and low adsorption of the
chelating agents on soils, But very few workers have attempted chelating agent to
extract metals from spent catalyst.
Case Study:
Distillation Column 4 (T-104) of process:, this equipment consists of a column,
condenser, reflux drum and reboiler.
Process conditions:
Inlet steam contains : ethanol, acetic acid and water inters the distillation with a
temperature of 83oC and pressure of 103 kPa.
Equipment description:
The distillation 4 (T-104) is a tray column with a total condenser. The purpose of this
distillation is to separate ethanol from other components.
Instrumentation:
For this distillation column we are controlling the inlet flow, temperature of the
bottom, level and composition of the reflux drum and pressure of the condenser.
Table (38):HAZOP Analysis on Distillation Column T-104
Deviations
Causes
Consequences
Recommended
actions
More temperature
flow.
temperature loop.
temperature alarm
on the loop.
separation in
column.
column to reboiler.
(flow indicator
alarm) for steam.
column to reboiler.
alarm on TT.
Less temperature
steam line.
215
More pressure
water.
alarm.
be increased.
valve.
on column.
stream from
column to
condenser.
water system for
condenser.
condenser.
controller set point.
drum.
Less pressure
separation.
pressure loop.
fault (set point).
rises.
flow loop.
valve.
decreases.
Same as less flow
Same as less flow
Same as less flow
fault.
stream entering
the column from
reboiler.
alarm.
drop in column.
point.
increases.
alarm.
pump.
release.
leakage.
open.
More flow
No flow
High level (in
bottom)
bottom pipe line.
line.
Low level (in
bottom)
malfunction (fail
to operate).
structure.
216
High level (in
reflux drum)
fault.
reflux drum.
pipe line.
the condenser
and the column.
alarm on reflux
drum.
Low level (in reflux
drum)
fault.
alarm on reflux
drum.
pipe line.
Change in
composition
cooling.
spec. (incorrect
specification).
upset.
changes.
loop settings.
Corrosove :
- We don’t have materials that could made corrosive , since acetic acid is a weak
acid and its concentration is low specially when we removed it with large amount
of waste water.
217
NFPA 704 Hazard Identification Systems:
National Fire Protection Agency NFPA 704 is a standard maintained by the U.S.based National Fire Protection Association. It defines the colloquial "fire diamond"
used by emergency personnel to quickly and easily identify the risks posed by
nearby hazardous materials. This is necessary to help determine what, if any,
specialty equipment should be used, procedures followed, or precautions taken
during the first moments of an emergency response.
It is contains four colors which divisions are typically color-coded, with blue
indicating level of health hazard, red indicating flammability, yellow (chemical)
reactivity, and white containing special codes for unique hazards. Each of health,
flammability and reactivity is rated on a scale from 0 (no hazard; normal
substance) to 4 (severe risk).
218
Health (blue)
4
3
2
1
Very short exposure could cause death or major residual injury (e.g., hydrogen
cyanide)
Short exposure could cause serious temporary or moderate residual injury
(e.g., chlorine gas)
Intense or continued but not chronic exposure could cause temporary
incapacitation or possible residual injury (e.g., chloroform)
Exposure would cause irritation with only minor residual injury (e.g.,
turpentine)
Poses no health hazard, no precautions necessary. (e.g., lanolin)
0
Flammability (red)
Will rapidly or completely vaporize at normal atmospheric pressure and
4 temperature, or is readily dispersed in air and will burn readily (e.g., propane).
Flash point below 23°C (73°F)
3
Liquids and solids that can be ignited under almost all ambient temperature
conditions (e.g., gasoline). Flash point below 38°C (100°F) but above 23°C
(73°F)
2
Must be moderately heated or exposed to relatively high ambient temperature
before ignition can occur (e.g., diesel fuel). Flash point between 38°C (100°F)
219
and 93°C (200°F)
1
Must be pre-heated before ignition can occur (e.g., soybean oil). Flash point
over 93°C (200°F)
0 Will not burn (e.g., water)
Instability/Reactivity (yellow)
4
Readily capable of detonation or explosive decomposition at normal
temperatures and pressures (e.g., nitroglycerine, RDX)
Capable of detonation or explosive decomposition but requires a strong
3 initiating source, must be heated under confinement before initiation, reacts
explosively with water, or will detonate if severely shocked (e.g. fluorine)
Undergoes violent chemical change at elevated temperatures and pressures,
2 reacts violently with water, or may form explosive mixtures with water (e.g.,
phosphorus, potassium, sodium)
1
0
Normally stable, (but can become unstable at elevated temperatures and
pressures)
Normally stable, even under fire exposure conditions, and is not reactive with
water (e.g. helium)
220
And the White (Special) color means:
The white "banda" area can contain several symbols:

W: reacts with Water in an unusual or dangerous manner (e.g., cesium,
sodium)

OX or OXY: Oxidizer (e.g., potassium perchlorate, ammonium nitrate)

COR: Corrosive; strong acid or base (e.g. sulfuric acid, potassium hydroxide)
o
ACID and ALK to be more specific.

BIO: Biological hazard (e.g., smallpox virus)

POI: Poisonous (e.g. Spider Venom),

The Radioactive trefoil (): is radioactive (e.g., plutonium, uranium)

CRY or CRYO: Cryogenic (e.g. Liquid Nitrogen)
221
Table(39): NFPA 704 of Main Components in our plant:
Component Name
NFPA 704
Carbon monoxide
Hydrogen
Ethanol
Acetaldehyde
Ethyl acetate
Acetic acid
222
Ch 5
Cost
Evaluation
223
In this chapter the plant economics have been evaluated by estimating the total capital
investment, yearly production costs, income from sales of the products and the profitability using
cap cost. The evaluation calculations are illustrated in following tables
1-
Equipment Cost
Table (40): Equipment Cost
Compressors
Compressor
Type
Power
(kilowatts)
Purchased
Equipment
Cost
Bare
Module
Cost
# Spares
MOC
$
631,000
$
1,730,000
$
519,000
$
1,420,000
C-101
Centrifugal
2290
0
Carbon
Steel
C-102
Centrifugal
1720
0
Carbon
Steel
Exchanger
Type
Shell
Pressure
(barg)
Tube
Exchangers
E-101
Floating
Head
E-102
Floating
Head
E-103
Floating
Head
140
0.048
1
Pressure
(barg)
MOC
0.048
Carbon
Steel /
Carbon
Steel
0.048
Carbon
Steel /
Carbon
Steel
112
Carbon
Steel /
Carbon
Area
(square
meters)
46.5
Purchased
Equipment Cost
$
25,000
Bare
Module
Cost
$
103,000
46.5
$
25,000
$
82,300
1000
$
176,000
$
606,000
224
Steel
Reactors
Type
R-101
Jacketed
Non-Agitated
R-102
Jacketed
Non-Agitated
Towers
Tower
Description
T-101
45 Carbon
Steel Sieve
Trays
T-102
128 Carbon
Steel Sieve
Trays
T-103
128 Carbon
Steel Sieve
Trays
Volume
(cubic
meters)
Purchased
Equipment Cost
36
Height
(meters)
38,200
$
57,300
20,100
$
30,200
Purchased
Equipment Cost
Bare
Module
Cost
$
15
$
Demister
MOC
Pressure
(barg)
Bare
Module
Cost
Diameter
(meters)
Tower
MOC
23.7
2.2
Carbon
Steel
1
$
215,000
62
4
Carbon
Steel
1
$
2,100,000
18
2.3
Carbon
Steel
5
$
492,000
T-104
66 Carbon
Steel Sieve
Trays
33.5
4
Carbon
Steel
1
$
1,090,000
$
2,240,000
T-105
80 Carbon
Steel Sieve
Trays
40
4
Carbon
Steel
1
$
1,320,000
$
2,700,000
T-106
6 Carbon
Steel Sieve
Trays
11.5
2.1
Carbon
Steel
112
$
55,900
$
1,850,000
225
$
450,000
$
4,290,000
$
787,000
Length/
Vessels
Orientation
Height
(meters)
Diameter
(meters)
MOC
V-101
Vertical
11.5
2.1
Carbon
Steel
Total Bare Module Cost
:
Demister
MOC
Pressure
(barg)
112
Purchased
Equipment Cost
$
38,900
Bare
Module
Cost
$ 1,830,000
$ 18,175,800
226
2-Utilities Summary:
Table (41): Utilities Summary:
Total Module
Cost
Grass Roots
Cost
V-101
$
2,040,000
$
1,680,000
$
121,000
$
97,000
$
716,000
$
67,600
$
35,700
$
531,000
$
5,060,000
$
930,000
$
2,650,000
$
3,180,000
$
2,180,000
$
2,160,000
$
2,910,000
$
2,390,000
$
162,000
$
138,000
$
1,010,000
$
87,000
$
45,700
$
756,000
$
7,060,000
$
1,270,000
$
3,690,000
$
4,440,000
$
2,270,000
$
2,240,000
Totals
$21,400,000
$28,500,000
Name
C-101
C-102
E-101
E-102
E-103
R-101
R-102
T-101
T-102
T-103
T-104
T-105
T-106
Actual Usage
Annual Utility
Cost
High Thermal Source
80000 MJ/h
$9,241,000
Low Thermal Source
500000 MJ/h
$51,310,000
Cooling Water
200000.016 MJ/h
$589,198
High Thermal Source
400000 MJ/h
$46,200,000
Medium-Pressure
Steam
200000.016 MJ/h
$23,617,838
Utility Used
NA
NA
NA
NA
NA
NA
NA
NA
NA
$130,958,036
227
3-Cost of Raw Material , Product and treatment of waste water
Table (42): Cost of Raw Material , Product and treatment of waste water
Material Name
Classification
Syngas
Raw Material
Ethanol
Product
Water
Non-Hazardous
Waste
Price ($/kg)
$
5.00
$(0.79)
$
0.04
Flowrate (kg/h)
Annual Cost
1234.00
$
51,346,740
31650.00
$
(207,815,736)
23932.00
$
7,169,836
endClassification
endMaterial
$
(207,815,736)
$
51,346,740
$
Economic Options
Cost of Land
$
7,169,836
$
7,169,836
$1,250,000
Taxation Rate
42%
Annual Interest Rate
10%
Salvage Value
0
custom
Working Capital
$8,000,000
function
FCIL
$28,500,000
CSGRC
Total Module Factor
1.18
Grass Roots Factor
0.50
Economic Information Calculated From Given Information
Revenue From Sales
CRM (Raw Materials Costs)
CUT (Cost of Utilities)
$207,815,736
material
$51,346,740
material
$130,958,036
COM
CWT (Waste Treatment Costs)
$7,169,836
material
COL (Cost of Operating Labor)
$158,700
material
-
Factors Used in Calculation of Cost of Manufacturing (COM d)
Comd = 0.18*FCIL + 2.76*COL + 1.23*(CUT + CWT + CRM)
228
Multiplying factor for FCIL
0.18
Multiplying factor for COL
2.76
Facotrs for CUT, CWT, and CRM
1.23
COMd
$238,621,784
Factors Used in Calculation of Working Capital
Working Capital = A*CRM + B*FCIL + C*COL
A
0.10
B
0.10
C
0.10
Project Life (Years after
Startup)
10
Construction period
2
Distribution of Fixed Capital Investment (must sum to one)
End of year One
60%
End of year Two
40%
229
Year
0
1
2
3
4
5
6
7
8
9
10
11
4-Cash Flow Diagram
Cash Flow Diagram
100.0
Project Value (millions of dollars)
80.0
60.0
40.0
20.0
0.0
-20.0
-40.0
-1
0
1
2
3
4
5
6
7
8
Project Life (Years)
9
10
11
12
Fig(71): Cash Flow Diagram
Table (43) Pay back period
Investment
1.25
25.10
FCIL-Sdk
28.50
28.50
-
R
COMd
(R-COMd-dk)*(1-t)+dk
207.82
207.82
207.82
207.82
207.82
207.82
207.82
207.82
207.82
207.82
179.07
179.07
179.07
179.07
179.07
179.07
179.07
179.07
179.07
179.07
19.07
20.50
18.97
18.05
18.05
17.37
16.67
16.67
16.67
16.67
Cash Flow
(Nondiscounted)
(1.25)
(25.10)
19.07
20.50
18.97
18.05
18.05
17.37
16.67
16.67
16.67
25.92
Cash Flow
(discounted)
(1.25)
(22.82)
15.76
15.40
12.96
11.21
10.19
8.91
7.78
7.07
6.43
9.09
Cumulative
Cash Flow
(discounted)
(1.25)
(24.07)
(8.31)
7.09
20.05
31.25
41.44
50.35
58.13
65.20
71.63
80.71
Cumulative
Cash Flow
(Nondiscounted)
(1.25)
(26.35)
(7.28)
13.22
32.19
50.23
68.28
85.65
102.32
118.99
135.66
161.58
230
Net Present ValueData
Low NPV
High NPV
-172.9
186.4
Bins
0
1
2
3
4
5
6
7
8
9
10
Upper Value
-172.9
-137.0
-101.0
-65.1
-29.2
6.7
42.7
78.6
114.5
150.5
186.4
# points/bin
0
5
22
74
156
232
235
156
99
19
2
Cumulative
0
5
27
101
257
489
724
880
979
998
1000
Cumulative Number of Data Points
1000
750
500
250
0
-200
-150
-100
-50
0
50
100
150
200
250
Net Present Value (millions of dollars)
Fig(72): Net Present Value
231
Discounted Cash Flow Rate of Return Data
Low
DCFROR
High
DCFROR
Bins
0
1
2
3
4
5
6
7
8
9
10
0.00
0.27
Upper
0.00
0.03
0.05
0.08
0.11
0.13
0.16
0.19
0.21
0.24
0.27
#/bin
0
63
68
126
140
169
159
108
68
29
3
Cumulative
0
63
131
257
397
566
725
833
901
930
933
Cumulative Number of Data Points
1000
750
500
250
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
DCFROR
232
Discounted Payback Period Data
Low DPBP
High DPBP
Bins
0
1
2
3
4
5
6
7
8
9
10
2.8
30.7
Upper
2.8
5.6
8.4
11.2
14.0
16.7
19.5
22.3
25.1
27.9
30.7
#/bin
0
263
321
163
82
56
35
24
0
6
6
Cumulative
0
263
584
747
829
885
920
944
944
950
956
Cumulative Number of Data Points
1000
750
500
250
0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
DPBP (years)
233
Cumulative Cash Position Data
Low CCP
High CCP
-213.33
533.67
Upper
Value
-213.33
-138.63
-63.93
10.77
85.47
160.17
234.87
309.57
384.27
458.97
533.67
Bins
0
1
2
3
4
5
6
7
8
9
10
# points/bin
0
4
20
54
124
195
228
173
118
69
15
Cumulativive
0
4
24
78
202
397
625
798
916
985
1000
Cumulative Number of Data Points
1000
750
500
250
0
-300
-200
-100
0
100
200
300
400
500
600
Cumulative Cash Position (millions of dollars)
Fig(73) : Cumulative Cash Position
234
Rate of Return on Investment Data
-14%
44%
Bins
0
1
2
3
4
5
6
7
8
9
10
Upper
Value
-14%
-8%
-2%
4%
10%
15%
21%
27%
33%
39%
44%
Cumulative Number of Data Points
Low ROROI
High ROROI
# points/bin
0
5
37
100
193
228
210
130
65
27
5
Cumulative
0
5
42
142
335
563
773
903
968
995
1000
1000
750
500
250
0
-20%
-10%
0%
10%
20%
30%
40%
50%
ROROI
235
Payback Period Data
Low DPBP
High DPBP
Bins
0
1
2
3
4
5
6
7
8
9
10
1.9
10.1
Upper
1.9
2.7
3.6
4.4
5.2
6.0
6.9
7.7
8.5
9.3
10.1
#/bin
0
214
314
155
109
70
32
16
37
12
2
Cumulative
0
214
528
683
792
862
894
910
947
959
961
Cumulative Number of Data Points
1000
750
500
250
0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
PBP (years)
Fig(74) : PBP vs Cumulative Number of Data Points
We can see that our plant will pay back in 3 years.
236
Conclusion
The ethanol plant is now completed after going through some calculations and research on our
product..
In the material and energy balances we worked on a simulator HYSYS and made a model of our
plant, some modifications to the original flowsheet along with several assumptions to simplify
our plant.
The equipment design is an important section where we worked on a detailed design on the
equipments. Most of the data for our calculations were taken from HYSYS, and as a result the
designs for all the equipments were reasonable. A HAZOP was made on a distillation column
was needed because if the separation is insufficient the plant will not produce the desired
product.
While the economics of the plant have been evaluated we noticed that the payback period was
estimated to be 3 years and the product sales are high compared to the raw material cost.
Thus this plant proves to be greatly favorable.
237
References
-Books
1. ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY -FOURTH EDITION- volume
2(editor {Mary Howe-Grant}).
2. ULLMANN'S ENCYCLOPEDIA OF IDUSTRIAL CHEMISTRY -FIVITH EDITIONvolume 10 (Executive editor-Wolfgang Gerhartz -senior editor-y.Stephen Yamamoto)
3. SRI of Styrene.
4. Industrial organic chemistry - Klaus Weissermel, Hans-Jürgen Arpe.
5. Handbook of petrochemicals production processes By Robert Allen Meyers.
6. Applied chemical engineering process.
7. Encyclopedia of chemical process and design.
8. Chemical engineering design – Coulson and Richardson’s chemical engineering series –
Fourth edition – Volume 6.
- Websites
- http://search.wvu.edu/search?q=ethanol+from+syngas+cost&btnG=
-http://www.freepatentsonline.com/5233100.html
https://www.pls.llnl.gov/data/docs/science_and_technology/chemistry/combustion/ethanol_paper.pdf
http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1903933328&
_sort=r&_st=13&view=c&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=f5531cb42
847532c051f9fe49a7c854f&searchtype=a
-http://www.mendeley.com/research/research-ethanol-synthesis-syngas/
-http://www.syntecbiofuel.com/thermochemical_process.php
-http://www.nrel.gov/biomass/publications.html
-http://www.dow.com/search.aspx?q=ethanol%20production%20flowsheet&start=10
238
Appendix
Insulation ranges
239
Calculating K1 Plate spacing anf FLV
Selection of liquid flow arrangement.
240
Relation between downcomer area and weir length.
Weep-point correlation.
241
Discharge coefficient, sieve plates.
242
243
Entrainment correlation for sieve plates.
Relation between hole area and pitch.
244
Relation between angle subtended by chord, chord height and chord length.
245
Thickness
Heat exchanger
246
Temparature correction factor:two shell passes;four or multiples of four tube passes.
247
Temparature correction factor:one shell passe;two or more even tube passes.
Shell-bundle clearance.
248
Renolds number
Fouling factors (coefficients), typical values
249
250
Typical overall heat transfer coefficients.
251
Standard dimensions for steel tubes
Constants to calculate Nt
252