College of Engineering and Petroleum
Chemical Engineering Department
Plant Design (ChE 491)
Equipment Design
Production of Ethanol
Group Members:
Khalid al-Sulaili
204215889
Mosleh Mohammed
207217019
Omar Ali
205112892
Yousef bahbahani
207111495
Eid Ali
206113669
Presented by:
Prof. Mohamed A. Fahim
Eng. Yusuf Ismail Al
1
Table of Contents
Subject
Page number
Abstract
3
Summary of Equipments Designed
4
Distillation columns
5-36
Reactors
37-48
Seprator
Heat exchangers
49-56
57-75
Air comprssors
76-105
Abstract:
2
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.
Summary of Equipments Designed.
3
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)
Distillation Column
4
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.
Types of Distillation Columns
There are many types of distillation columns, each designed to perform specific types of
5
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 :
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
6
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
single feed and two product streams is shown below:
7
Figure.1 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.2 Stripping Section
8
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.3 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
9
the cap, finally discharging through slots in the cap, and finally bubbling through the
liquid on the tray.
Figure.4 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.
10
Figure.5 Valve tray
Sieve trays
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.6 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:
1234-
The pressure drop among the plates is small.
It is cheaper and has a good efficiency.
ease of maintenance .
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.
11
Figure.7 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.
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.
12
Figure.9 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.
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
13
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
Nomenclatures
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)
14
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)
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:
15
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.
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.
16
19) Calculate Thickness of the distillation.
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
17
Column diameter:
Liquid vapor flow factor:
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 3-8 Flooding velocity for sieve plates
From the figure above:
18
Base K1 = 0.08
Top K1 = 0.1
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)
19
Taking downcomer area as 12 per cent of total.
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)
20
Figure 3-9 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)
21
Figure 3-10 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
22
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 3-11 Weep point correlation (Eduljee, 1959)
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.
23
Plate pressure drop:
Dry plate drop
Maximum vapor velocity through holes (uh) = Bottom Vmax/Hole area Ah = 10.395 (m/s)
Figure 3-12 Discharge coefficient, sieve plates (Liebson et al. 1957)
From the figure above:
Plate thickness / hole dia. = 1.25
Ah
x100  10
Ap
Co  0.86


24
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



25
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
26
Figure 3-13 Entrainment correlation for sieve plates (Fair, 1961)
From the figure above:
ψ =0.013 , well below 0.1
Perforated area:
27
Figure 3-14 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

28
Figure 3-15 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
29
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
30
Thickness Calculations:
Internal raduis of shell before allowance corrosion is added r i
= 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 
31
Specification sheet of Acetaldehyde Column T-101
Equipment Name
Acetaldehyde Column
32
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
Specification sheet of Ethyl acetate Column T-103
Equipment Name
Distillation column
Objective
To separate ethyle acetate
33
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
Specification Sheet for Distillation column (T-103)
34
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
Ethyl
Light
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
Specification sheet of Ethyl acetate Column T-104
Equipment Name
Distillation column
Objective
To separate ethyle acetate
35
Designer
Oma
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
Specification sheet of Ethyl acetate Column T-105
Equipment Name
Distillation column
Objective
To separate ethyle acetate
Designer
Kh
Type
Tray column
Material of Construction
Carbon steel
36
Minral wool and glass fiber
Insulation
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
37
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.
38
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
the speed of the reaction. The following picture shows the packed catalyst in a reactor
Figure 3.7: Fixed-bed Reactorin industry
39
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.
40
41
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)
42
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)
43
L = 4.5815 (m)
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)
44
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
Gases (Tube side)
Parameter
Temperature Ti
Mass Density ρ
Specific Heat Cp
Mass Flow Rate
Unit
o
C
kg/m3
kJ/kg.C
kg/s
Inlet
325
7.0841
9.5
Outlet
408.4
6.4486
9.5
108
108
Cooling water (shell side)
Parameter
Temperature ti
Specific Heat Cp
Mass Flow Rate
Unit
Inlet
o
C
KJ/Kg.K
kg/s
Outlet
25
4.2
47.322
280
4.286
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)
Mean Temperature difference:-
Tlm 
R 
T1
T1
 t 2   T2  t1 
 T1  t 2  
ln 
 T  t  

2
1


t 2  t1 
 T2 
;S 
t t
T t
45
T2
408.4
o
C
T1
325 oC
Tw2
Change in the phase
Tw1
25 oC
200 oC
<Temperature Profile>
T1
o
325
T2
o
408.4
t1
o
25
t2
o
200
∆Tlm
o
230.5
R
S
No need to find R & S (the
reason is below)
-
C
C
C
C
C
-
Ft= 1 (because I have 1
shell & 1 tube)
Q= U.A.∆Tm
46
A= 130611111.1 /(160.45*230.5)
→A = 3531.522 m2
From table 2 in appendix,
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
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
47
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
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)
48
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
D=(V/ π)1/3 =(15/ π)1/3 =1.68 m
H=4D =4*1.68=6.73 m
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
-----------------------------------------------------------------------49
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
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.
50
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
51
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
Vertical separator
Material of Construction:-
52
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.
Table 3.30 Nomenclatures
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)
53
Hv
Liquid depth (m)
ri
Inside radius of the shell before corrosion (m)
H
Length (m)
Do
Outlet diameter (m)
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
54
Hv = VHV / [(pi / 4) * (Dv )2 ] = 3.8 (m)
ri = Dv / 2 = 1.103 (m) = 43.434 (in)
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
specification sheet for separator V-100
Equipment Name
Separator
55
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
(oC)
60
Operating Pressure (psi)
1640
2.2
Height (m)
9.7
Dimensions
Diameter (m)
56
57
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.
58
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.
59
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
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.
60
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.
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.
61
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 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
62
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.
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.
63
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.
Selection of solvent:
64
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.
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
65
Symbol
Definition
Lw
Liquid mass flow rate (Kg/s)
Vw
Vapor mass flow rate (Kg/s)
Flv
Liquid vapor flow factor
K1
Correction for surface tension
uf
Flooding vapor velocity (m/s)
Vmax
Maximum volumetric flow rate
Anet
Net area (m2)
H
Height of column (m)
Dc
Column diameter (m)
Ac
Column area (m2)
Ad
Down comer area (m2)
Aa
Active area (m2)
Ah
Hole area (m2)
how
Height of the liquid crest over weir (mm liquid)
uv
Vapor velocity (m/s)
dh
Hole diameter(m)
hd
Dry plat drop (mm liquid)
hr
Residual head (mm liquid)
ht
Total pressure drop (mm liquid)
T
Thickness (mm)
66
Ej
Efficiency of joints
S
Working stress (psi)
Cc
Allowance for corrosion (in)
ri
Inside radius (in)
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
67
Detailed calculation procedure:
1. the column diameter
Flv 
Lw
Vw
v
l
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
68
uf  K1
(v  l )
v
Where,
uf : flooding vapor velocity (m/s)
Design for 85%flooding at maximum flow rate
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)
69
2. Maximum volumetric liquid rate
Maximum volumetric liquid rate=
LbottomMw
3600 *  l
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)
70
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
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
2
how
 L 3
 750 w 
 l lw 
Where,
how: height of the liquid crest over weir (mm Liquid)
71
Assuming,
take hole diameter(mm)
plate thickness (mm)
weir height(hw) (mm)
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
72
6. Plate pressure drop
Maximum vapor velocity through holes = Max volumetric flow
rate/Ah
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
73


Pri
  Cc
t 
 ( SE  0.6 P 
j


Where,
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)=
74
 L
hdc (m 2 )  166 w max
 ( A
 l ap




2
Lwd: liquid flow rate in down comer (kg/s)
Am: either Ad , or Aad (the smaller ) (m2)
hb (mm) = hw +how +ht +hdc
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
75
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
76
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
77
Fig. 54: Shell and Tube Heat Exchangers (a)
78
Fig. 55: 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.
79
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.
80
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.
81
Nomenclature
Table 1.1: Nomenclature of Heat exchanger
Symbol
Definition
T1
Inlet shell side fluid temperature (°C)
T2
Outlet shell side fluid temperature(°C)
82
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)
lb
Baffle spacing (m)
T
Shell Thickness
∆Pt
Tube side pressure drop (N/m2)
Np
Number of tube side passes
Ej
Efficiency of joints
83
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
Detailed calculation procedure
84
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)
T2: is outlet shell side fluid temperature (°C)
t1: is inlet tube side temperature (°C)
85
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,
(Dimensionless).
S: is temperature efficiency of the heat exchanger, (dimensionless)
86
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)
87
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)
Mass velocity = mass flow rate / total flow area, (kg /sec.m2)
88
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)
Equivalent diameter for triangular arrangement (de) =1.1*(pt2-0.917do2) /do, (mm)
89
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)
9- Pressure drop
90
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)
lb: baffle spacing(m)
Use fig.(12.30) to get jf.
91
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)
92
Sample Calculation :
Heat exchanger
93
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
T1
C
350
T2
C
309.95
94
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 )
R= 8.401
95
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
Choose,
96
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
Use a split – ring floating head type.
From figure (A.12) in appendix
97
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
Tube cross sectional area = 7.85E-5m2
98
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
 kf
hi  Nu
 di
0.33
 
  
w

0.14
; jh  f (
L
)
di



Re=1883.2953
99
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 = 


Re  9432643.6
100
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



Uo= 331.3700W/m2 °C)
101
Pressure drop:
Tube side
From figure (12.24)and for Re =1883.295
jf= 1E-3
assume viscosity=0.89

 u 2
 L / di 
  2.5
pt  N p 8 j f 
  / w 

 2



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
Pt  1044812bar
102
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.
103
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
104
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
105
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
106
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:
107
Centrifugal compressors
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).
108
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
An animation of an axial compressor.
109
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
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
110
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.
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)
111
n = compression factor
2. Get the value of work done (W):
W 
nR (T1 T 2 )
1 n
where R= Cp / Cv
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
112
Sample Calculations on (K-100)
P1 (psi)
P2 (psi)
)T1) (R)
T2 (R)
R = (Cp/Cv)
M (lbmole/s)
Cp (Btu/lb. °F)
Mwt
300
1037.6
559.6704
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
113
2.
W 
nR (T1 T 2 )
1 n
w = (1.5735398*1.4018*(559.6704-879.75))/(1-1.5735398)
=1231.00044(Btu/lbmol)
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 %
114
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
(◦C)
Inlet Pressure (psia)
559.6704
300
Outlet Temperature
(◦C)
Outlet Pressure (psia)
879.75
1037.6
79.519400
Efficiency (%)
Power (Hp)
3030.304
%
115
Specification sheet for Air compressor( K-101)
Equipment Name
Objective
Equipment Number
Designer
Type
Compressor
To increase the pressure
K-101
Kh
Reciprocating Compressor
Material of Construction
Carbon steel
Insulation
Quartz wool
Cost
$ 119,100
Operating Condition
Inlet Temperature
(◦C)
Inlet Pressure (psia)
559.6704
300
Outlet Temperature
(◦C)
Outlet Pressure (psia)
879.75
1037.6
79.519400
Efficiency (%)
Power (Hp)
3030.304
%
116