A Project Report on
PRODUCTION OF ANILINE
SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIRMENTS FOR THE
AWARD OF THE DEGRE OF
BACHELOR OF TECHNOLOGY
IN
CHEMICAL ENGINEERING
Submitted By
Tejaswi Pothuganti (9626)
V. Blessystella (9632)
Mallikarjun Reddy G (9647)
Mohith Nigam (9671)
Under the Guidance of
Mrs. Srivani, Associate Professor
DEPARTMENT OF CHEMICAL ENGINEERING
NATIONAL INSTITUTE OF TECHNOLOGY
WARANGAL-506004 (A.P)
2012-2013
1
DEPARTMENT OF CHEMICAL ENGINEERING
NATIONAL INSTITUTE OF TECHNOLOGY
WARANGAL-506004
CERTIFICATE
This is to certify that the project entitled “Production of ANILINE” carried out by Ms.
Tejaswi Pothuganti (9626), Ms. V. Blessystella (9632), Mr. Mallikarjun Reddy G (9647),
Mr. Mohith Nigam (9671) of final year B.Tech Chemical Engineering during the year 20122013 is a bonafide work submitted to the National Institute of Technology, Warangal in
partial fulfilment of requirements for the award of degree of Bachelor of Technology.
Project Guide
Mrs. Srivani
AssociateProfessor
Dept. of Chemical Engineering
NIT Warangal
Head of the Department
Prof. Y Pydi Setty
Professor
Dept. Of Chemical Engineering
NIT-Warangal
2
ACKNOWLEDGEMENT
We would like to express our deep sense of respect and gratitude toward our supervisor Mrs.
K. Srivani, Associate Professor, Department of Electronics and Communication
Engineering, National Institute of Technology, Warangal who not only guided the academic
project work but also stood as a teacher. Her presence and optimism have provided an
invaluable influence on my career and outlook for the future. We consider it as our good
fortune to have got an opportunity to work with such a wonderful person.
We express my gratitude to Prof. Y.Pydisetty, Head of Department of Chemical Engineering,
Mr. Srinu Naik, Project In charge, Department of Chemical Engineering and its faculty
members and staff for extending all possible help in carrying out the dissertation work
directly or indirectly. They have been great source of inspiration to us and we thank them
from bottom of my heart. We would like to acknowledge our institute, National Institute of
Technology, Warangal, for providing good facilities to complete our thesis work.
We would also like to take this opportunity to acknowledge our friends for their support and
encouragement. We are especially indebted to our parents for their love, sacrifice and
support.
Tejaswi Pothuganti (09626)
V. Blessystella (09632)
G. Mallikarjuna Reddy (09647)
Mohit Nigam (09671)
3
INDEX
Chapter
No
Page no
Chapter name
1
Introduction
1
2
Market Analysis
2
3
Uses
6
4
Physical & Chemical Properties
8
5
Different Manufacturing Process
14
6
Selection of Process
17
7
Process Description
18
8
Mass balance
22
9
Energy balance
35
10
Design of major Equipment
50
11
Cost estimation
80
12
Plant layout and location
84
13
Pollution control and Safety
89
14
Bibliography
94
4
1. INTRODUCTION:
Aniline, phenylamine or aminobenzene is
an organic
compound with
the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the
prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is
in the manufacture of precursors topolyurethane. Like most volatile amines, it possesses the
somewhat unpleasant odour of rotten fish. It ignites readily, burning with a smoky flame
characteristic of aromatic compounds. Aniline is colourless, but it slowly oxidizes and
resinifies in air, giving a red-brown tint to aged samples.
From a historical perspective, aniline is perhaps one of the more important
synthetic organic chemicals ever manufactured. In 1856, Sir William Henry Perkin, a student
at the Royal College of Chemistry in London, discovered and isolated a purple dye during the
oxidation of impure aniline. The discovery of this dye, known as mauve, created quite a stir
and Perkin, seeing the value of his discovery, proceeded to scale up the synthetic process for
the production of mauve, which included the synthesis of aniline. This process was to become
one of the first commercial processes to generate a synthetic organic chemical.
During the last three decades, polyurethane plastics have emerged as a growth industry and
aniline once again plays a key role as an industrial intermediate used in the manufacture of
MDI, 4,4’-diphenylmethane diisocyanate, a key commercial monomer in the manufacture of
polyurethane plastics.
Aniline is produced by the reduction of nitrobenzene, which is produced from the nitration of
benzene in a mixture of sulphuric and nitric acid.
5
2. MARKET ANALYSIS:
MDI (Methylene Diphenyl Diisocyanate) production accounts for over 75% of world aniline
consumption; other large applications include use as a chemical intermediate for rubberprocessing chemicals, dyes and pigments. Since most MDI producers are captive in aniline
and its precursor nitrobenzene, typically in integrated units, nearly all MDI expansions result
in increased production and consumption of nitrobenzene/aniline. MDI has been the driving
force behind world growth in aniline demand since 1982. Future demand for aniline will
continue to depend largely on MDI requirements.
MDI is consumed in polyurethane (PU) foam, both rigid and flexible. Most rigid PU foam is
used in construction and appliances while flexible PU foam is used primarily in furniture and
transportation. As a result, consumption of nitrobenzene/aniline/MDI largely follows the
patterns of the leading world economies and depends heavily on construction/remodelling
activity (residential and non-residential), automotive production and original equipment
manufacturer. MDI growth has been driven by "green" initiatives, sustainability and lowering
CO2 emissions.
World consumption of aniline grew at an average annual rate of 3% during 2006–2010, the
result of a growing global economy during 2001–2008, declines during the economic
recession in 2009 and the recovery in 2010, and growth due to increased MDI capacity.
Strong Asian demand for all applications of MDI boosted world demand during 2006–2010.
World consumption of aniline is forecast to grow at an average annual rate of 3.8% during
2010–2015. Continuing rapid demand growth in some regions, particularly in China, Other
6
Asia
and
Europe,
mainly
the
result
of
continued
expansion
of
integrated
nitrobenzene/aniline/MDI units, will balance out moderate growth in markets such as the
Americas.
The aniline industry is a concentrated one, with most producers integrated into MDI
production. BASF, Huntsman, Bayer and DuPont are the four dominant players, with about
17%, 12%, 12% and 10% of the world's capacity, respectively; only DuPont is not an MDI
producer. BASF, Huntsman and Bayer each have plants in several world regions.
2.1. Supply/demand:
Global capacity was 4.98m tonnes/year in 2006, with 1.62m tonnes/year in Western Europe,
1.38m tonnes/year in the US, 1.15m tonnes/year in Asia-Pacific (excluding Japan), 474,000
tonnes/year in Japan, 316,500 tonnes/year in Eastern Europe, 70,000 tonnes/year in Latin
America and 64,000 tonnes/year in Asia/Middle East.
Western Europe is the largest consumer, at about 1.32m tonnes/year, followed by the US at
1.19m tonnes/year and Asia-Pacific at 717,860 tonnes/year. Japan, Asia/Middle East and
Latin America consume 319,190 tonnes/year, 98,360 tonnes/year and 73,130 tonnes/year,
respectively. Global demand in 2006 was 3.95m tonnes/year.
2.2. Prices:
There is a small merchant market and prices typically track benzene. European prices in the
fourth quarter were €0.98-1.06/kg. November contracts in the US and Asia-Pacific were
$0.62-0.68/lb and $1.29-1.40/kg, respectively.
2.3. Technology
Most production is based on the catalytic hydrogenation of nitrobenzene, where benzene is
mixed with a solution of nitric acid, hydrogenated and then purified by distillation.
Another route, by SABIC/Sud-Chemie partnership Scientific Design, is the vapour phase
ammonolysis ofphenol using excess ammonia and a silica-alumina catalyst, but this is now
only used by Mitsui.
2.4. Outlook
Global demand growth is put at 6%/year to 2010. Annual consumption will rise by 10.5% in
Asia-Pacific, 6.5% in Asia/Middle East, 5.6% in Western Europe, 5.1% in the US, and 1.5%
in Japan, respectively. Other world regions will grow by 3-4%/year.
There is plenty of capacity until 2012. In China, Bayer will build a 247,000 tonne/year unit
for 2009 and Yantai Wanhua's hike to 95,000 tonnes/year was due by late 2007. South
7
Korea's Kumho Mitsui will double output to 90,000 tonnes/year in 2009. Japan's Tosoh will
expand to 300,000 tonnes/year by 2008. Karun Petrochemical plans a 30,000 tonne/year unit
in Iran, for 2009. India's Hindustan Organic Chemicals may restart a 60,000 tonne/year unit
by 2008 or later.
2.4. MAJOR GLOBAL ANILINE CAPACITY '000 TONNES/YEAR(Table-1)
Company
Location
Capacity
BASF
Antwerp, Belgium
430
Geismar, Louisiana, US
264
Yeocheon, South Korea
60
Yeosu, South Korea
140
Antwerp, Belgium
140
Brunsbuttel, Germany
180
Krefeld, Germany
166
Sao Paulo, Brazil
60
Borsodchem
Ostrava, Czech Republic
150
Dow Chemical
Bohlen, Germany
130
Estarreja, Portugal
125
Baytown, Texas, US
250
Beaumont, Texas, US
150
Bayer
DuPont
Pascagoula, Mississippi, US 240
Huntsman
Geismar, Louisiana, US
460
8
Wilton, UK
450
Lanzhou Chemical Industry
Lanzhou, China
106
Shandong Haihua
Weifang, China
50
Shanghai Lianheng Isocyanate
Caojing, China
177
Shanxi Tianji Coal
Tianji, China
130
Singpu Chemicals
Yancheng, China
90
Sinopec Nanjing Chemical
Nanjing, China
135
Sumitomo Mitsui Chemical
Chiba, Japan
124
Sumitomo-Bayer
Kurosaki, Japan
100
Tosoh
Nanyo, Japan
150
Volzhskiy Orgsintez
Novomoskovsk, Russia
50
* excludes units under 50,000 tonnes/year
SOURCE: CHEMPLAN BY TRANTECH CONSULTANTS
9
3. USES OF ANILINE:
Aniline, an organic base used to make dyes, drugs, explosives, plastics, and photographic and
rubber chemicals.
Aniline, a primary aromatic amine, is a weak base and forms salts with mineral acids. In
acidic solution, nitrous acid converts aniline into a diazonium salt that is an intermediate in
the preparation of a great number of dyes and other organic compounds of commercial
interest. When aniline is heated with organic acids, it gives amides, called ‘Anilides’, such as
acetanilide from aniline and acetic acid. Monomethylaniline and dimethylaniline can be
prepared from aniline and methyl alcohol. Catalytic reduction of aniline yields
cyclohexylamine. Various oxidizing agents convert aniline to quinone, azobenzene,
nitrosobenzene, p-aminophenol, and the phenazine dye aniline black.
The great commercial value of aniline was due to the readiness with which it yields, directly
or indirectly, dyestuffs. The discovery of mauve in 1856 by William Henry Perkin was the
first of a series of dyestuffs that are now to be numbered by hundreds. Reference should be
made to the articles dyeing, fuchsine, safranine, indulines, for more details on this subject.
In addition to its use as a precursor to dyestuffs, it is a starting-product for the manufacture
of many drugs, such as paracetamol (acetaminophen, Tylenol).It is used to stain neural RNA
blue in the Nissl stain.
At the present time, the largest market for aniline is preparation of methylene diphenyl
diisocyanate (MDI), some 85% of aniline serving this market. Other uses include rubber
processing chemicals (9%), herbicides (2%), and dyes and pigments (2%).
When polymerized, aniline can be used as a type of nanowire for use as a semiconducting
electrode bridge, most recently used for nano-scale devices such as biosensors. These
polyanilineg nanowires can be doped with a dopant accordingly in order to achieve certain
semiconducting properties.
3.1. Developments in medicine
In the late 19th century, aniline emerged as an analgesic drug, its cardiac-suppressive side
effects countered with caffeine.[11] In the 20th century's first decade, modifying synthetic
dyes to treatsleeping sickness, Paul Ehrlich—who had coined the term chemotherapy for
his magic bullet approach to medicine—failed and switched to modifying Béchamp's atoxyl,
10
the first organic arsenicaldrug, and serendipitously attained the syphilis treatment salvarsan,
the first successful chemotherapy. Salvarsan's targeted microorganism, not yet recognized as
bacteria, was still thought a parasite, however, and medical bacteriologists, believing bacteria
not susceptible to the chemotherapeutic approach, overlooked Alexander Fleming's 1929
report on the in vitro effect ofpenicillin.[12]
In 1932, Bayer sought medical applications of its dyes. Gerhard Domagk identified
as antibacterial a red azo dye, introduced in 1935 as the first antibacterial drug, prontosil,
rapidly found atPasteur Institute to be a prodrug degraded in vivo to sulfanilamide—a
colorless intermediate for many, highly colorfast azo dyes—already off patent, synthesized in
1908 in Vienna by Paul Gelmofor his doctoral thesis.[12] By the 1940s, over 500 related sulfa
drugs were produced.[12] In high demand via World War II (1939–45), these first miracle
drugs, chemotherapy of wide effectiveness, propelled the American pharmaceutics
industry.[13] In 1939, at Oxford University, seeking an alternative to sulfa drugs, Howard
Florey developed Fleming's penicillin into the first systemicantibiotic drug, penicillin G.
(Gramicidin, developed by René Dubos at Rockefeller Institute in 1939, was the first
antibiotic,
yet
its
toxicity restricted
it
to topical use.)
After WWII, Cornelius
P.
Rhoads introduced the chemotherapeutic approach to cancer treatment.[14]
11
4. PHYSICAL& CHEMICAL PROPERTIES:
4.1. PHYSICAL PROPERTIES[1}:(Table-2)
PROPERTY
VALUE
Molecular Formula
C6H7N
Molecular Weight
93.129
Boiling point, 0C
101.3 K Pa
184.4
4.4 K Pa
92
1.2 K Pa
71
0
Freezing Point C
-6.03
Density,liquid,g/mL
1.02173
Density,Vapor,(at bp,air=1)
3.30
Refractive Index
1.5863
Viscosity, mPa.s(=cP)
20 0C
4.35
60
1.62
Enthalpy of dissociation, kJ/mole
21.7
Heat of combustion, kJ/mole
3394
Ionisation potential, eV
7.70
0
Dielectric constant, at 25 C
6.89
Dipole moment at 250C,C.m
5.20*10-30
Specific heat at 250C,J/(g.K)
2.06
Heat of vaporization, J/g
478.5
Flash point,0C
Closed cup
70
Open cup
75.5
Ignition Temperature, 0C
615
Lower flammable limit, vol %
1.3
Odour Threshold,ppm
2.4
Physical state and appearance
Liquid. (Oily liquid.)
12
Odour:
Aromatic. Amine like.
Taste:
Burning.
Water/Oil Dist. Coeff.
The product is more soluble in oil;
log(oil/water) = 0.9
Critical Temperature
425.6°C (798.1°F)
4.2. CHEMICAL PROPERTIES[1]:
Aromatic amines are usually weaker bases than aliphatic amines by the difference in P ka of
the conjugate acids of aniline. Pka of Aniline is 4.63 and Pka of cyclo hexyl amine is 10.66.
This is due to resonance effect. Aniline is stabilized by sharing its lone-pair electrons with the
aromatic ring.
Aromatic amines form addition compounds and complexes with many inorganic substances,
such as Zinc chloride,copper chloride, Uranium Tetrachloride, or Boron Trifloride.Various
metals react with amino group to form metal anilides; Hydrochloric, sulphuric, or Phosphoric
acid salts of aniline are important intermediates in the dye industry.
4.2.1 N-alkylation[1]:
A number of methods are available for preparation of N-alkyl and N,N-dialkyl derivatives of
aromatic amines. Passing a mixture of aniline and methanol over a copper-zinc oxide catalyst
at 2500C and 101 kPa reportedly gives N-methylaniline. Heating aniline with methanol under
pressure or with excess methanol produces N,N-dimethylaniline. In the presence of sulphuric
acid, aniline reacts with methanol to form N-methyl and N,N-dimethyl aniline. This is a two
step process as shown.
C6H5NH2 + CH3OH C6H5NHCH3 + H2O
C6H5NHCH3 + CH3OH C6H5NH(CH3)2 + H2O
13
4.2.2. Ring Alkylation [1]:
The aromatic ring undergoes alkylation under certain conditions. For example,2-ethylaniline,
2-6-diethylaniline, or mixture of the two are obtained in high yield when aniline is heated
with ethylene in the presence of aluminium-anilide catalyst(formed by heating aluminium
and aniline) at 3300 C and 4-5 MPa.
4.2.3. Acylation [1]:
Aromatic amines react with acids, acid chlorides, anhydrides, and esters to form amides.In
general,acid chlorides give the best yield of the pure product. The reaction with
acetic,propionic,butanoic, or benzoic acid can be catalysed with phosphorous oxychloride or
trichloride.
N-Phenylsuccinimide (succanil) is obtained in essentially quantitative yield by heating
equivalent amounts of succinic acid and aniline at 140-1500C. the reaction of a primary
aromatic amine with phosgene leads to formation of an arylcarbamoyl chloride, that when
heated loses hydrogen chloride to form isocyanate. Commercially important isocyanates are
obtained from aromatic primary diamines.
Conversion of aniline to acetanilide, by reaction with acetic anhydride, is a convenient
method for protecting the amino group. The acetyl group can later be removed by acid or
base hydrolysis.
4.2.4. Condensation [1]:
Depending on the reaction conditions, a variety of condensation products are obtained from
the reaction of aromatic amines with aldehydes, ketones, acetals, and orthoformates.
Primary aromatic amines react with aldehydes to form Schiff bases. Schiff bases formed from
the reaction of lower aliphatic aldehydes, such as formaldehyde and acetaldehyde, with
primary aromatic amines are often unstable and polymerize readily. Aniline reacts with
formaldehyde in aqueous acid solutions to yield mixtures of a crystalline trimer of the Schiff
base, methylenedianilines, and polymers.
14
4.2.5. Cyclization [1]:
Aniline, nitrobenzene, and glycerol react under acid catalysis (Skraup synthesis) to form
quinolone.
The Skraup synthesis is a chemical reaction used to synthesize quinolines. It is named after
the Czech chemist Zdenko Hans Skraup (1850-1910). In the archetypal Skraup, aniline is
heated with sulfuric acid, glycerol, and an oxidizing agent,likenitrobenzene to yield
quinoline.
In this example, nitrobenzene serves as both the solvent and the oxidizing agent. The
reaction, which otherwise has a reputation for being violent ("the Chemical Inquisition"), is
typically conducted in the presence of ferrous sulphate.Arsenic acid may be used instead of
nitrobenzene and the former is better since the reaction is less violent.
15
4.2.6. Halogenation [1]:
The presence of the amino group activates the ortho and para positions of the aromatic ring
and, as a result, aniline reacts readily with bromine or chlorine. Under mild conditions,
bromination yields 2,4,6- tribromoaniline.
4.2.7. Oxidation [1]: Aniline was selectively converted into the corresponding nitrosobenzene
and nitrobenzene by oxidation with 30% aqueous hydrogen peroxide. The reaction was
catalyzed by various heteropolyoxometalates, at room temperature, in dichloromethane under
two-phase conditions. Findings show that H3PW12O40 is the best catalyst in the oxidation of
aniline. Na3PW9Mo3O40 and K4SiW9Mo2O39 also displayed high reactivity in the oxygenation
system. Phase transfer agents and temperature increase also contribute to the efficiency of the
oxidation
4.2.8.ReactivityProfile[1]:
Aniline is a heat sensitive base. Combines with acids to form salts. Dissolves alkali metals
or alkaline earth metals with evolution of hydrogen. Incompatible with albumin, solutions of
iron, zinc and aluminum, and acids. Couples readily with phenols and aromatic amines.
Easily acylated and alkylated. Corrosive to copper and copper alloys. Can react vigorously
with oxidizing materials (including perchloric acid, fuming nitric acid, sodium peroxide and
ozone). Reacts violently with BCl3. Mixtures with toluene diisocyanate may ignite.
Undergoes explosive reactions with benzenediazonium-2-carboxylate, dibenzoyl peroxide,
fluorine nitrate, nitrosyl perchlorate, peroxodisulfuric acid and tetranitromethane. Violent
reactions may occur with peroxyformic acid, diisopropyl peroxydicarbonate, fluorine,
trichloronitromethane (293° F), acetic anhydride, chlorosulfonic acid, hexachloromelamine,
(HNO3 + N2O4 + H2SO4), (nitrobenzene + glycerin), oleum, (HCHO + HClO4),
perchromates, K2O2, beta-propiolactone, AgClO4, Na2O2, H2SO4, trichloromelamine,
acids, FO3Cl, diisopropyl peroxy-dicarbonate, n-haloimides and trichloronitromethane.
16
Ignites on contact with sodium peroxide + water. Forms heat or shock sensitive explosive
mixtures with anilinium chloride (detonates at 464° F/7.6 bar), nitromethane, hydrogen
peroxide, 1-chloro-2,3-epoxypropane and peroxomonosulfuric acid. It reacts with perchloryl
fluoride form explosive products. .
17
5. DIFFERENT WAYS OF PRODUCTION:
5.1. From Nitrobenzene:
Nitrobenzene is the classical feedstock for Aniline manufacture. Recently less Chlorobenzene
and Phenol are being used in aniline manufacturing processes in several countries.
The reduction of nitrobenzene with iron turnings and water in the presence of small amounts
of hydrochloric acid is the oldest form of industrial aniline manufacture. It would certainly
have been replaced much earlier by more economical reduction methods if it had not been
possible to obtain valuable iron oxide pigments from the resulting iron oxide sludge.
However, the increasing demand for aniline has far surpassed the market for the pigments, so
that not only catalytic hydrogenation processes (both liquid- and gas-phase) but also other
feed stocks have been used for aniline production.
The modern catalytic gas-phase hydrogenation processes for nitrobenzene can be carried out
using a fixed-bed or a fluidized-bed reactor:
Rayer and Allied work with nickel sulfide catalysts at 300-475 °C in a fixed bed. The
activation of the hydrogenation catalysts with Cu or Cr, and the use of different supports and
catalyst sulfidization methods with sulfate, H2S or CS2 all belong to the expertise of the
corresponding firms. The selectivity to aniline is more than 99%. The catalytic activity
slowly decreases due to carbon deposition. However, the catalyst can be regenerated with air
at 250-350°C and subsequent H2 treatment. Similar processes are operated by Lonza with Cu
on pumice, by ICI with Cu, Mn, or Fe catalysts with various modifications involving other
metals, and by Sumitomo with a Cu-Cr system.
The gas-phase hydrogenation of nitrobenzene with a fluidized-bed catalyst is used in
processes from BASF, Cyanamid and Lonza. The BASF catalyst consists of Cu, Cr, Ba, and
Zn oxides on a SiO2 support; the Cyanamid catalyst consists of Cu/SiO2. The hydrogenation
is conducted at 270-290 °C and 1-5 bar in the presence of a large excess of hydrogen
(H2:Nitrobenzene=ca. 9:1). The high heat of reaction is removed by a cooling system which
18
is built into the fluidized bed. The selectivity to aniline is 99.5%; the nitrobenzene conversion
is quantitative. The catalyst must be regenerated with air periodically.
5.2. From Chlorobenzene:
An alternate manufacturing route for aniline is the ammonolysis of chlorobenzene or of
phenol. For example, in the Kanto Electrochemical Co. process, chlorobenzene is
ammonolyred to aniline with aqueous NH3 at 180-220 °C and 60-75 bar in the presence of
Cucl and NH3Cl (Niewland catalyst).
Aniline can be isolated with 91 % selectivity from the organic phase of the two-phasereaction
product.
5.3.From Phenol:
Dow stopped operation of a similar process for aniline in 1966. Phenol can also be subjected
to gas-phase ammonolysis with the Halcon/Scientific Design process at 200 bar and 425 °C:
Al2O3.SiO2 (possible as zeolites) and oxide mixtures of Mg, B, Al, and Ti are used as
catalysts; these can be combined with additional co catalysts such as Ce,V, or W. The catalyst
regeneration required previously is not necessary with the newly developed catalyst. With a
large excess of NH3, the selectivity to aniline is 87-90% at a phenol conversion of 98%. The
byproducts are diphenylamine and carbazole. This process has been operated since 1970 by
Mitsui Petrochemical in a plant which has since been expanded to 45 000 tonnes per year. A
second plant with a capacity of 90000 tonnes per year was started up by US Steel Corp. (now
Aristech) in 1982.
5.4. From Benzene:
Du Pont has developed an interesting manufacturing process for aniline. Benzene and NH3
can be reacted over a NiO/Ni catalyst containing promoters including zirconium oxide at
19
350°C & 300 bar to give a 97% selectivity to aniline with benzene conversion of 13%
Since the hydrogen formed in the reaction reduces the NiO part of the catalyst, a catalyst
regeneration (partial oxidation) is necessary. Despite inexpensive feedstocks, industrial
implementation is still thwarted by the low benzene conversion and the necessary catalyst
re-oxidation.
20
6. CHOICE OF PROCESS:
The catalytic Hydrogenation of Nitrobenzene to Aniline gives selectivity more than 99%,
better than other manufacturing processes.
Nitrobenzene is the classical feedstock for Aniline manufacture.
The method process is simple, inexpensive catalysts, long life, from product quality,
After preheating the hydrogen and nitrobenzene, hydrogenation reaction occurs. Fixed bed
gas phase catalytic hydrogenation process has a matured technology, the reaction temperature
is lower, equipment has easy operation, low maintenance costs, less investment, without
separation of catalyst, good product quality; deficiency is, the reaction pressure is more prone
to occurrence of local side effects caused by overheating and catalyst deactivation, the
catalyst must be periodically replaced. Currently, most foreign manufacturers of fixed-bed
use gas phase aniline hydrogenation process.
21
7. PROCESS DESCRIPTION
Rayer and Allied work with nickel sulphide catalysts at 300-475 °C in a fixed bed. The
activation of the hydrogenation catalysts with Cu or Cr, and the use of different supports and
catalyst sulfidization methods with sulphate, H2S or CS2 all belong to the expertise of the
corresponding firms. The selectivity to aniline is more than 99%. The catalytic activity
slowly decreases due to carbon deposition. However, the catalyst can be regenerated with air
at 250-350°C and subsequent H2 treatment. Similar processes are operated by Lonza with Cu
on pumice, by ICI with Cu, Mn, or Fe catalysts with various modifications involving other
metals, and by Sumitomo with a Cu-Cr system.
Table 3: Physical properties for aniline and water [2]
Aniline
Water
Chemical Formula
C6H7N
H2O
(Mw) (g/mol)
93.128
18.015
Tb(K)
457.15
373.15
Tm(K)
267.13
273.15
Antoine A
7.43481
8.02927
Antoine B(◦C)
1813.917
1713.681
Antoine C(◦C)
213.709
232.633
Vapor pressure A
66.287
73.649
Vapor pressure B(K)
-8207.1
-7258.2
Vapor pressure C
-6.0132
-7.3037
Vapor pressure D
2.84 ·
4.17 ·
10−18
10−6
Vapor pressure E
6
2
Density A(kmol)
1.0405
5.459
Density B(m3)
0.2807
0.30542
Density C(K)
699.0
647.13
Density D
0.29236
0.081
22
23
Antoine equation:
Liquid–liquid Properties
If liquid–liquid extraction is to be performed, the liquid–liquid equilibrium behaviour must be
known.
An important liquid–liquid temperature dependent property is the solubility. From
Sørensen et al. (14) mol percents representing aniline dissolved in water and water
dissolved in aniline are shown in table.
Table 4: Solubility of aniline in water and water in aniline[2]
Temperature(◦C)
Mol percent aniline
Mol percent water
20.0
0.674
21.3
25.0
0.679
21.8
Weight percent aniline
Weight percent water
20.0
3.39
4.98
25.0
3.41
5.12
The solubility of aniline dissolved in water from table 2.2 show that water is more
soluble in aniline than aniline is in water
Vapor–Liquid Properties :
If distillation separation is to be used to separate the mixture, the vapor–liquid behaviour
must be known, and because the aniline–water system does not behave ideally, the
activity coefficients are of interest. From Gmehling et al (2) the Margules, van Laar,
Wilson, NRTL and UNIQUAC model parameters are listed in table 2.3.
24
Table 5: Model Parameters and γi∞ for different models[2]
A12
A21
Margules
1.0041
3.1217
2.73
Van Laar
1.2006
8.3006
3.32 4026.37
Wilson
1608.4375
2513.9461
NRTL
6945.2299 -
22.68
3.11
229.00
3.68
104.01
3.49
554.62
2651.2199
UNIQUAC 1439.0048
-379.5945
In table 5 index 1 represents water and index 2 aniline.
All the methods show that
, which is consistent with table 2.2, which shows that
aniline is less soluble in water than water is in aniline. The large γ2∞ found by the Van
Laar model is not a typing error, and therefore a strong confirmation of the low solubility
of aniline in water.
Investigations of a VLE–diagram show that an azeotrope exists for the aniline–water
binary system. Horyna et al (16) have found the azeotrope to be at a water weight fraction
of x1 = 0.808 (water mol fraction of 0.956) and a temperature of 98.6◦C, at a pressure of
742mmHg. A VLE–diagram estimated using the VLE UNIFAC model at 760mmHg in
SMSWIN is shown in figure 2.1 to the right. It is similar to the proportional diagram
from Gmehling et al (2), the diagram to the left. Both diagrams show an azeotrope at the
weight fraction x1 ≈ 0.96, corresponding to the one determined by Horyna et al,
indicating that the VLE UNIFAC model is a good approximating for the vapor–liquid
behaviour of a aniline–water binary system.
Figure 1: VLE diagrams for the binary aniline/water system at 1atm. The left diagram is
experimentally determined, and the right is estimated using the VLE UNIFAC model[2].
25
An estimated number of the distillation stages needed to perform the distillations in
figure 1 can be found using the Margules equations from Smith et al. (13).
The Margules equations represent a commonly used empirical model of solution behaviour
and are defined as
lnγ1 = x22 [A12 + 2(A21 − A12)x1]
lnγ2 = x21 [A21 + 2(A12 − A21)x2]
(3.2)
From the values of A12 and A21 given in table 2.3, the activity coefficients can be
determined, and in relation to the vapor pressures, the relative volatility can be
determined as done by King (4)
26
27
8. MASS BALANCE:
Basis: Production of Aniline (99.5% purity) is 218788.529 tons/year.
Assumptions:

No of plant working days=300 days

100% conversion of Nitrobenzene.

200% excess of Hydrogen is used.

Reactants are pure.
Average molecular weight=0.995*93.1262+0.005*18.0152=92.7506.
So, 218788.529 tons per year =30387.29578 kg/hr
=327.623 kmol/hr.
Based amount of Nitrobenzene required is
=326.632 kmol/hr,
=326.632*123.1092,
=40211.40421 kg/hr.
The ratio of Hydrogen to Nitrobenzene is= 9:1
Amount of hydrogen required =9*326.632 =2939.688 kmol/hr
=5925.82307 kg/hr.
Hydrogen from recycle =6*326.632 =1959.792 kmol/hr
=3950.548714 kg/hr.
Fresh feed of Hydrogen= 3*326.632 =979.896 kmol/hr
=1975.274356 kg/hr.
Mass balance for Vaporiser:
Stream1A:
Pure Nitrobenzene feed in liquid phase=326.632 kmol/hr
=40211.40421 kg/hr
Stream1B:
Nitrobenzene from vaporizer in vapor phase=326.632 kmol/hr
=40211.40421 kg/hr
28
Mass balance for the reactor:
Stream1B:
Nitrobenzene from vaporizer in vapor phase=326.632 kmol/hr
=40211.40421 kg/hr
29
Stream2:
Fresh Hydrogen feed=979.896 kmol/hr = 1975.27436 kg/hr.
Stream3:
Makeup Hydrogen or recycle=1959.792 kmol/hr = 3950.54871 kg/hr.
Stream4:
Total amount of Hydrogen
=2939.688 kmol/hr = 5925.82307 kg/hr.
Stream5:
Nitrobenzene vapor stream=40211.40421 kg/hr
Total Hydrogen feed to the reactor=5925.82307 kg/hr
Total feed to Fluidized bed reactor =46137.22728 kg/hr
Stream6:
Product stream consists of Aniline, water and unreacted Hydrogen, all in vapor phase.
Aniline=326.632 kmol/hr = 30417.99696 kg/hr
Water=653.264 kmol/hr = 11768.68161 kg/hr
Unreacted Hydrogen = 1959.792 kmol/hr = 3950.54871 kg/hr.
Table 6:
Flow
IN
OUT
Component
Stream 1B(kg/hr) Stream 2(kg/hr) Stream 4(kg/hr)
Stream 6(kg/hr)
Nitrobenzene
40211.40421
---
---
---
Hydrogen
---
1975.27436
3950.54871
3950.54871
Water
---
---
---
11768.68161
Aniline
---
---
---
30417.99696
40211.40421
1975.274356
3950.548714
TOTAL(kg/hr)
TOTAL(kg/hr)
46137.22728
46137.22728
46137.22728
30
Mass Balance for the condenser:
Stream6:
Reactor Product stream consists of Aniline, water and unreacted Hydrogen, all in vapor
phase.
Aniline=326.632 kmol/hr
=30417.99696 kg/hr
Water=653.264 kmol/hr
=11768.68161 kg/hr
Unreacted Hydrogen=1959.792 kmol/hr
=3950.54871 kg/hr.
Stream3:
Makeup or unreacted Hydrogen or recycle=1959.792 kmol/hr
=3950.54871kg/hr.
Stream7:
Consists of condensed Water and Aniline.
Aniline=326.632 kmol/hr
=30417.99696 kg/hr
Water=653.264 kmol/hr
=11768.68161 kg/hr
31
Table 7:
Flow
IN
OUT
Component
Stream 6(kg/hr)
Stream 3(kg/hr)
Stream 7(kg/hr)
---
---
---
Hydrogen
3950.548714
3950.54871
---
Water
11768.68161
---
11768.68161
Aniline
30417.99696
---
30417.99696
Total (kg/hr)
46137.22728
3950.54871
42186.67857
Nitrobenzene
OUT
Mass balance for the Decanter:
Stream7:
Consists of condensed Water and Aniline.
Aniline=326.632 kmol/hr =30417.99696 kg/hr
Water=653.264 kmol/hr =11768.68161 kg/hr
Stream 12:
Water=32698.53348 kg/hr
32
Aniline=7042.02739 kg/hr
Stream13:
Water=5117.73724 kg/hr
Aniline=1392.55056kg/hr
Stream9:
Water=44437.73942 kg/hr
Aniline=7102.20424kg/hr
Stream 10:
Water =5147.21291kg/hr
Aniline=31750.37067kg/hr
Table 7
Flow
IN
OUT
OUT
Stream
Stream
Stream
Stream
Stream
7(kg/hr)
12(kg/hr)
13(kg/hr)
9(kg/hr)
10(kg/hr)
Nitrobenzene
---
---
---
---
---
Hydrogen
---
---
---
---
---
Component
5147.21291
Water
11768.68161 32698.53348
5117.73724
44437.73942
31750.37067
Aniline
30417.99696
7042.02739
1392.55056
7102.20424
TOTAL(kg/hr)
42186.67857 39740.56087
6510.28780
51539.94366
TOTAL(kg/hr)
88437.52724
36897.58358
88437.52724
Mass balance for the distillation column 1:
33
Stream9:
Water=44437.73942 kg/hr
Aniline=7102.20424kg/hr
Stream 11:
Water =11739.20594 kg/hr
Aniline=60.17685 kg/hr
Stream 12:
Water =32698.53348 kg/hr.
Aniline=7042.02739 kg/hr
34
Table 8:
Flow
IN
Component
Stream 9(kg/hr)
Nitrobenzene
OUT
OUT
Stream 11(kg/hr) Stream 12(kg/hr)
---
---
---
Hydrogen
---
---
---
Water
44437.73942
11739.20594
32698.53348
Aniline
7102.20424
60.17685
7042.02739
Total (kg/hr)
51539.94366
11799.38279
39740.56087
Mass balance for Distillation column2:
Stream 10:
Water =5147.21291 kg/hr
Aniline=31750.37067 kg/hr
Stream13:
Distillate stream enriched with water
Aniline=1392.55056kg/hr
35
Water=5117.73724 kg/hr
Stream14:
Bottom stream enriched with Aniline
Aniline=30387.29578 kg/hr
Water=29.47567 kg/hr
Table 9:
Flow
IN
Component
Stream 10(kg/hr)
Nitrobenzene
OUT
OUT
Stream 13(kg/hr) Stream 14(kg/hr)
---
---
---
Hydrogen
---
---
---
Water
5147.21291
5117.73724
29.47567
Aniline
31750.37067
1392.55056
30387.29578
Total (kg/hr)
36897.58358
6510.28780
30387.29578
36
37
9. DETAILED ENERGY BALANCE
Heat capacity data:
Nitrobenzene = 1.4 kj/kg.K
Hydrogen[5] = 6.62+ 0.00081T(K) cal/mol.K = 13.727+0.00168T kj/kg.K
Aniline[5] =1.415℮5 + 1.712℮2T j/kmol.K
Water in liquid phase[6] = (8.712 +1.25*10-3T -0.18*10-6T2)*R
Water in gas phase[6] = (3.470 + 1.45*10-3T+0.121/T2)*R
Energy balance for the Nitrobenzene vaporizer:
Heat in:
38
Nitrobenzene is at room temperature of 298 K.
So enthalpy in =0
Heat out:
Nitrobenzene is heated from 298 to 553.15 K
Enthalpy associated with Nitrobenzene = m ∫
+ m ∆Hv +∫
Enthalpy of vaporization of Nitrobenzene ∆Hv =33 kj/kg.
Enthalpy associated with Nitrobenzene
+40211.40421*33 +∫
= 40211.40421*∫
kj/hr
=19631609.7 kj/hr
Heat supplied by the Vaporizer=enthalpy out-enthalpy in
=15690892.1+3940717.6
=19631609.7 kj/hr
Table 10:
Flow
IN
IN
OUT
Heat supplied
Component
Stream1A (kj/hr)
(kj/hr)
Stream1B (kj/hr)
0
19631609.7
19631609.7
Hydrogen
---
---
---
Water
---
---
0
Aniline
---
---
0
Total (kg/hr)
0
19631609.7
19631609.7
Nitrobenzene
39
Energy balance for the reactor:
Heat in:
Enthalpy in with Nitrobenzene=19631609.7kj/hr
Enthalpy in with Hydrogen=
∫
kj/hr
=5925.82307*∫
=27939805.8 kj/hr
Total enthalpy in=19631609.7 +27939805.8 =47571415.5 kj/hr
Heat Generated :
Heat generated by reaction = 443 kj/mol=443000 kj/kmol
Total heat generated = 443000*326.632 = 144697976 kj/hr
40
Heat removed by Coolant :
The temperature in the reactor reaches an average peak temperature of 700 K due to
exothermic reaction.
∆Hf0298 of Aniline=31.3 kj/mol=31300 kj/kmol
Heat with Aniline
=m∫
+ m ∆Hv
= (42440+10-3 ∫
)*m
=14718691 kj/hr
Heat with Water= m ∫
+ m ∆Hv
=m∫
+m∫
+ m ∆Hv
=979.896*(40680+∫
+∫
)
=979.896*(40680+5692.6+11543.7) =979.896*57916.3
= 56751950.7 kj/hr
Heat with Hydrogen= m ∫
=3950.54871*∫
=26697609.23 kj/hr
Total enthalpy out due to products=14718691+56751950.7 +26697609.23
=98168250.93 kj/hr
Total heat removed by the Coolant
= Total enthalpy in-total enthalpy out+total heat generated by the reaction
= 47571415.5 -98168250.93 +144697976
= 94101140.57 kj/kg
41
Table 11:
Flow
IN
OUT
Heat removed
Component
Stream1B (kj/hr)
Stream4 (kj/hr)
Stream6 (kj/hr)
Stream (kj/hr)
19631609.7
---
---
---
Hydrogen
---
27939805.8
26697609.23
Water
---
---
56751950.7
Aniline
---
---
14718691
19631609.7
27939805.8
98168250.93
Nitrobenzene
TOTAL(kg/hr)
TOTAL(kg/hr)
47571415.5
94101140.57
98168250.93
Energy Balance for the condenser:
Enthalpy in:
Heat with Aniline =14718691 kj/hr
Heat with Water= 56751950.7 kj/hr
Heat with Hydrogen= 26697609.23 kj/hr
Total enthalpy in due to products = 14718691+56751950.7 +26697609.23
=98168250.93 kj/hr
Enthalpy out:
As condenser removes the latent heat and sensible heat in gas phase, all streams are cooled to
bubble point of Aniline and Water mixture which is 371.69 K.
42
So, Enthalpy with aniline=326.632*10-3*∫
=107008.6 kj/hr
Enthalpy with water
=979.896
*(∫
)
=5469289.4 kj/hr
Enthalpy with Hydrogen= m ∫
=3950.54871*∫
=4159912.7 kj/hr
Total enthalpy out=107008.6+5469289.4+4159912.7=9736210.7 kj/hr
Heat removed by condenser=387779355.3-98168250.93
=289611104.4 kj/hr.
Table 12:
Flow
IN
OUT
OUT
Heat Removed
Component
Stream6 (kj/hr)
Stream (kj/hr)
Stream7 (kj/hr)
Nitrobenzene
---
---
---
Hydrogen
14718691
---
4159912.7
Water
56751950.7
---
5469289.4
---
107008.6
289611104.4
9736210.7
Aniline
Total (kg/hr)
26697609.23
98168250.93
Energy balance for the pre-cooler:
This heat exchanger removes heat such that temperature of the stream is reduced to 303.15 K
from 371.69 K.
Enthalpy in:
Enthalpy with aniline = 107008.6 kj/hr
Enthalpy with water
= 5469289.4 kj/hr
Total enthalpy out
= 107008.6+5469289.4 = 5576298 kj/hr
43
Enthalpy out:
So, enthalpy with aniline = 326.632*10-3*∫
= 6947.3 kj/hr
Enthalpy with water
*(∫
= 979.896
)
= 380604.8 kj/hr
Total enthalpy out = 6947.3 +380604.8 = 387552.1 kj/hr
Heat removed by the heat exchanger = 5576298-387552.1 = 5188745.9 kj/hr
Energy balance for the decanter:
So, stream 7: enthalpy with aniline = 6947.3 kj/hr
Enthalpy with water =380604.8 kj/hr
Total enthalpy in=6947.3 +380604.8 =387552.1 kj/hr
Stream 12:
Water=32698.53348 kg/hr =1815.052 kmol/hr
Aniline=7042.02739 kg/hr =75.62 kmol/hr
Enthalpy with aniline = 75.62 *10-3*∫
=1562.56 kj/hr
Enthalpy with water
=
*(∫
44
= 704990.6 kj/hr
Total enthalpy =1562.56+704990.6=706553.16 kj/hr
Stream13:
Water=5117.73724 kg/hr =284.08 kmol/hr
Aniline=1392.55056kg/hr =14.95 kmol/hr
Enthalpy with aniline =14.95 *10-3*∫
=308.92 kj/hr
Enthalpy with water
=(284.08)
*(∫
=110340.49 kj/hr
Total enthalpy=308.92+110340.49=110649.41 kj/hr
Enthalpy out:
Stream9:
Water = 44437.73942 kg/hr = 2466.68 kmol/hr
Aniline =7102.20424kg/hr =76.26 kmol/hr
Enthalpy with aniline = 76.26 *10-3*∫
= 1575.79 kj/hr
Enthalpy with water
=2466.68 *
*(∫
=958091.68 kj/hr
Total enthalpy=1575.79+958091.68=959666.79 kj/hr
Stream 10:
Water =5147.21291kg/hr =285.72 kmol/hr
Aniline =31750.37067kg/hr =340.94 kmol/hr
Enthalpy with aniline =340.94 *10-3*∫
45
=7044.96 kj/hr
Enthalpy with water
=285.72 *
*(∫
=110977.49
Total enthalpy = 7044.96+110977.49 =118022.45 kj/hr
Table 13:
Flow
Component
IN
IN
IN
OUT
OUT
Stream
Stream
Stream
Stream
Stream
7(kj/hr)
12(kj/hr)
13(kj/hr)
9(kj/hr)
10(kj/hr)
Nitrobenzene
---
---
---
---
---
Hydrogen
---
---
---
---
---
Water
380604.8
704990.6
110340.49
958091.68
110977.49
Aniline
6947.3
1562.56
308.92
1575.79
7044.96
Total (kg/hr)
387552.1
706553.16
110649.41
959666.79
118022.45
Energy balance for distillation column-1:
46
Enthalpy in:
Stream9:
Water =44437.73942 kg/hr =2466.68 kmol/hr
Aniline =7102.20424kg/hr
=76.26 kmol/hr
Enthalpy with aniline =76.26 *10-3*∫
=26474.61 kj/hr
Enthalpy with water
=2466.68 *
*(∫
=14511181.32 kj/hr
Total enthalpy=26474.61 +14511181.32 =14537655.93 kj/hr
Enthalpy out:
Stream 11:
Water =11739.20594 kg/hr =651.628 kmol/hr
Aniline =60.17685 kg/hr =0.646 kmol/hr
Enthalpy with aniline =0.646 *10-3*∫
=216.6 kj/hr
Enthalpy with water
= 651.628 *
*(∫
=3714415.04 kj/hr
Total enthalpy=216.6+3714415.04=3714631.64 kj/hr
Stream 12:
Water =32698.53348 kg/hr =1815.052 kmol/hr
Aniline =7042.02739 kg/hr =75.618 kmol/hr
Enthalpy with aniline =75.618 *10-3*∫
=26589.81 kj/hr
Enthalpy with water
47
=1815.052 *
*(∫
=10802091.76 kj/hr
Total enthalpy =26589.81+10802091.76 = 10828681.57 kj/hr
Total enthalpy out=3714631.64+10828681.57=14543313.21 kj/hr
Heat supplied by the distillation column=14543313.21-14537655.93=5657.28 kj/hr
Table 14:
Flow
IN
OUT
Component
Stream (kj/hr)
Stream (kj/hr)
Stream (kj/hr)
---
---
---
Hydrogen
---
---
---
Water
14511181.32
3714415.04
10802091.76
216.6
26589.81
3714631.64
10828681.57
Nitrobenzene
Aniline
Total (kg/hr)
26474.61
14537655.93
14537655.93
OUT
14543313.21
Energy balance for distillation column-2:
48
Enthalpy in:
Stream 10:
Water = 5147.21291kg/hr =285.72 kmol/hr
Aniline=31750.37067kg/hr=340.94 kmol/hr
Enthalpy with aniline =340.94 *10-3*∫
=195845.11 kj/hr
Enthalpy with water
=285.72 *
*(∫
=2627299.22 kj/hr
Total enthalpy=195845.11+2627299.22 =2823144.33 kj/hr
Enthalpy out:
Stream13:
Distillate stream enriched with water
Aniline = 1392.55056kg/hr=14.953 kmol/hr
Water = 5117.73724 kg/hr=284.079 kmol/hr
Enthalpy with aniline=14.953 *10-3*∫
=5317.53 kj/hr
Enthalpy with water
=284.079 *
*(∫
=1707969.4 kj/hr
Total enthalpy=5317.53+1707969.4=1713286.93 kj/hr
Stream14:
Bottom stream enriched with Aniline
Aniline=30387.29578 kg/hr=326.302 kmol/hr
Water=29.47567 kg/hr=1.636 kmol/hr
49
Enthalpy with aniline= 326.302 *10-3*∫
= 259532.9 kj/hr
Enthalpy with water
=1.636 *
*(∫
=9836.13 kj/hr
Total enthalpy = 259532.9 +9836.13 = 269369.03 kj/hr
Total enthalpy out from distillation column=1713286.93+269369.03 =1982655.96 kj/hr
Total heat removed by distillation column =1982655.96-2823144.33 =-840488.37 kj/hr
Table 15:
Flow
IN
OUT
Component
Stream (kj/hr)
Stream (kj/hr)
Stream (kj/hr)
---
---
---
Hydrogen
---
---
---
Water
2627299.22
1707969.4
9836.13
5317.53
259532.9
1713286.93
269369.03
Nitrobenzene
Aniline
Total (kg/hr)
195845.11
2823144.33
2823144.33
OUT
1982655.96
50
10. DESIGN OF EQUIPMENTS
Symbols used in design of Shell and Tube heat exchanger:
A - heat transfer area, m2 or ft2
B - baffle spacing, in
cp - specific heat at constant pressure, J/g oC or Btu/lb oF
C- clearance, in
hi -heat-transfer coefficient for inside of tube ,W/m2 oC or Btu/ft2 oF h
hio -heat-transfer coefficient for outside of tube, W/m2 oC or Btu/ft2 oF h
ho - shell side heat-transfer coefficient, W/m2 oC or Btu/ft2 oF h
G - mass velocity, kg/m2 s or lb/ft2h
K -thermal conductivity , W/m oC
LMTD -logarithmic mean temperature difference
PT – tube pitch, in
Q - quantity of heat, J or Btu
Re – Reynolds number
U - overall heat-transfer coefficient, W/m2 oC or Btu/ft2 oF h
51
10.1 DESIGN OF SHELL AND TUBE HEAT EXCHANGER
Cold Fluid Data:
Inlet Temperature t1=21 oC =69.8 oF
Outlet Temperature t2=210 oC =410 oF
Weight flow w=40211.4021 kg/hr
Calculation of Heat load:
Qh= m Cp ∆T
= 40211.4021*1.4*(210-25)
=10414753.14 kg/hr
Qc= m Cp ∆T
m= Qc/(Cp ∆T)
= 10414753.14/(∆H)
=10414753.14/(2801.5-2643.7)
=65999.7 Kg
Hot Fluid data:
Inlet Temperature T1=250oC
Outlet Temperature T2=80oF
Weight flow W=65999.7 kg/hr
Calculation of ∆TLMTD:
∆TLMTD= ∆T1-∆T2 / ln(∆T1/∆T2)
∆TLMTD= 47.10oF
Calculation of R and S values:
R= (T2-T1)/(t2-t1)
52
= 0.918
S = (t2-t1)/(T2-t1)
= 0.822
Calculation of Correction Factor:
FT is found using LMTD correction factor curves
From Graph we get, FT=0.845
The values of R and S satisfy with Correction factor value for 4-8 shell and tube heat
exchanger.
This may be met by four 1-2 exchangers in series or two 2-4 exchangers in series.
∆tln= ∆TLMTD*FT
= 47.1*0.845 = 39.79ᴼF
Calculation of ud
From the literature the UD value of Nitrobenzene ranges from 60-90 W/m2K
Assume a value of UD
Let the value of UD be 80
Calculation of heat transfer area
A= Q/ UD*∆t
= 9871279.951/(80*39.79)
= 3101.05 ft2
Length of the tube L=16’0’’(3/4 in.OD,16BWG)-Square pitch
From the table, Flow area per tube a’t=0.302in2
Outside area per linear ft a’’=0.1963 ft2
Tube inside diameter D=0.62 in (Obtained from tables)
53
No. of tubes per shell, Nt= Heat transfer area/(No. of shell side passes* total surface area)
Nt= 3101.05/(2*16*0.1963)
= 493.67
= 494 tubes
For 4 passes, 3/4in.OD on 1-in. Square pitch (from the table),Nearest count(from 494 tubes):
480 tubes in a 29in.ID shell
Calculation of corrected UD:
Ud,corr = Q/A* ∆ T LMTD.
A= No. of passes * No. of tubes * Length of the tube * Outside area
= 2* 480* 16* 0.1963
=3015.16 ft2
UD= Q/(A*∆T)
=9871279.951/(3015.16*39.79)
=82.27
Tube side Calculation:
at = Nt * at/(144n)
=480* 0.302/(144*4)
= 0.252 ft2
Mass velocity:
Gt = w/ at
= 65999.7/(0454*0.252)
=576880.11 lb/ hr ft2
At Tavg= 180ᴼC
54
Ret = D*Gt / µ
Tube inside diameter = D = 0.62in
= 0.62/12 =0.0517
Ret = 0.0517*576880.11/(0.0375)
=795325.37
J factor for heat transfer curve jH
At L/D = 16/0.0517
jH = 750
Cp = 0.47 btu/lb
K = 0.0187 btu/ hr.ft2. ᴼF
hi = jH *(K/D)*(Cµ/K)1/3
= 750*(0.187/0.0517)*(0.47*0.0375/0.187)1/3
= 265.975 = 266
hio= hi * ID/OD
= 265.97 * 0.62/0.75
=220 btu/hr. ft2.ᴼF
At Re = 7,95,325.37
F= 0.0001, S= 0.7
Tube side pressure drop (∆Pt) = f Gt2 Ln/(5.22*1010*D *S)
∆Pt= 0.0001*576880.112*16*4/(5.22*1010*0.0517*0.7)
=1.125 Psi
Gt = 576880.11 v2/2g = 0.037
∆Pr = 4n/ S*(v2/2g)
55
= 4*4*(0.037)/0.7 =0.84
Total pressure drop (∆PT) = ∆Pt +∆Pr
= 1.125+ 0.84
=1.965 Psi
Shell side Calculations:
B= 12in
C = 0.25in
PT= C + Tube OD = 0.25+0.75 =1 in
Flow area as = ID* C*B/(144PT) = (29*0.25*12)/(144*2) = 0.302 ft2
Mass velocity :
Gs= W/as = 40211.4021/(0.454*0.302) = 293282.68 lb/ hr.ft2
T avg= 117.5ᴼC
µ = 0.4 Cp = 0.4*2.42 = 0.968 lb/ft. hr
Res = De* Gs/µ = 23985.75
JH =80
K = 0.16 W/ m.K
= 0.16*6.93 btu/hr. ft2.ᴼF
=1.1088 btu/hr. ft2.ᴼF
ho = jH* K/ D*(Cµ/K)1/3
= 80*1.1088/0.792*(0.968*0.334/1.1088)1/3
= 742.68 btu/hr. ft2.ᴼF
f = 0.0018, S= 0.76
No. of Crosses N+1 = 12L/ B
56
= 12*4*16/12 =64
Shell diameter Ds= 29/12 = 2.41 ft
Shell side pressure drop
∆Ps = f Gs2Ds(N+1)/(5.22*1010*0..079*0.76)
= 7.619 Psi
Clean overall Coefficient Uc:
Uc = hio* ho/(hio+ho)
= 95.87 btu/hr.ft2.ᴼF
Rd = UC- UD/( UC*UD)
= 95.87-82.27/(95.87*82.27)
=1.72*10-3 hr.ft2.ᴼF/ btu
57
Specification sheet of heat exchanger
Item
Heat Exchanger
Type
Two 2-4 shell & tube heat exchangers in
series
Operation
Continuous
Inlet temp. processing stream
69.8 °F
Outlet temp. processing temp.
410 °F
LMTD
47.10°F
UC
95.87 Btu /hr. ft2.°F
UD
82.27 Btu /hr. ft2.°F
No.of tubes
480
Pressure drop shell side
7.619 psi
Pressure drop tube side
1.965 psi
Heat transfer area
3015.16 ft2
Length of the tube
16 ft
Tube inner dia
0.0517 ft
Tube outer dia
0.0625 ft
Shell inner dia
1.9375 ft
Pitch
1 inch (square)
Baffle spacing
1 ft
No of baffles
16
58
Symbols used in the Design of the Reactor design:
P1 , P2 = pressure of the gas
T1 , T2 = temperature of gas
V1 , V2 = volume of gas
do=tube of outside diameter
di =Inside diameter of tube
TR =Residence time
Vg = volumetric flow rate of gas through reactor
V= volume of reactor
N= be no. of tubes,
A= Heat transfer area
Pt=Triangular tube pitch
Db = Bundle diameter
Di = shell Internal Diameter
J = weld joint efficiency factor
t =thickness of dome
q =Total Heat removed
U Heat transfer coefficient:
B=baffle spacing
59
10.2 DESIGN OF FIXED BED REACTOR
10.2.1. Estimation of volume of Reacting mixture:
1 kmol : 22.414 m3( at STP)
P1V1/T1=P2V2/T2
1*22.414/273= 3* V2/593
V2=17.05 m3
1 kmol of hydrogen at 3 atm and 350 C =17.05 m3
1 kmol of reactant mixture =123.1092*0.1+2.0158*0.9=14.152 gm
46137.22728kg/hr of reactants =3260.12kmol/hr =55585.046m3/hr=15.44 m3/s
10.2.2. Estimation of volume of products mixture:
P1V1/T1=P2V2/T2
1*22.414/273 =2*V2/600
V2=24.63 m3
1 kmol of products at 2 atm and 600 K =24.63 m3
1 kmol of product mixture =15.69gm,
46137.22728kg/hr of product mixture =2940.55 kmol/hr = 65909.49 m3/hr=18.31 m3/s
Basis: 16.875 m3/s of gas
Use 1.5” tubes of outside diameter (BWG 10no) and length =4m
Wall thickness for BWG 10 no tube =0.134”
Therefore, Inside diameter of tube =1.5-2*0.134=1.232”=31.3 mm
Volume of each tube = π/4 * d2*L= π/4 (31.2928*10-3)2*4=3.0764*10-3m3
Assumption:Residence time with in reactor =0.4 sec
60
T =volume of reactor/volumetric flow rate of gas through reactor,so volume of reactor is
V=Residence time * Volumetric flowrate= 0.4*16.875=6.75 m3.
Let ‘N” be no.of tubes,
N (3.0764*10-3) = 6.75
N = 2194.12 = 2194 tubes (approx.)
Heat transfer area =N (π*do*h) = 2194*π*38.1*10-3* 4= 1050.44 m2
Triangular pitch is used to accommodate 2194 no of tubes.
Triangular tube pitch,
Pt=1.25do
=1.25 *38.1=47.625 mm
Bundle diameter:Db =do (Nt/K1)1/n1,Where K1, n1 are obtained from the table below based on
the type of tube arrangement.
=38.1(2194/0.319)1/2.142=2358 mm
Graph: Shell inside diametervs. bundle diameter
By extrapolating the bundle diameter to 2.358 m,we have Shell ID –Bundle dia = 20 + (2010)*(5.41-1.2)/ (1.2-0.2) =31.58 mm
Therefore shell ID =Bundle diameter + 31.58 mm= 2358 +31.58=5545.83 mm =2389.58 mm
Height of a reactor = 10m
Volume of a reactor = (π/4)*D2*H= (π/4) (2.38958)2 *10=44.85 m3
10.2.3. Shell
Material of Construction:
The preferred construction material for reactor is low alloy steel (IS: 3609)
From Code IS 2825, f=12.6 kgf/mm2=1260 kgf/cm2
This is a Class-I vessel. Therefore, J = weld joint efficiency factor = 1
61
Here t = P*Di/(200fJ-P) +CA
Where P=3 atm= (3.04*10-2*2389.58)/ (200*1*12.6-3.04 *10-2) + 1=1.029 mm
Since t< 12 mm, Use t =12 mm (including corrosion allowance) in order to withstand its own
weight.
10.2.4. ellipsoidal dome end:
Calculation of Dome end Thickness:t = PDoC/200f J +CA +TA
Assume t=10 mm
hi =Di/4 =2389.58/4 =597.395 mm
ho =hi+ t =597.395 +10 =607.395 mm
Ro=0.82Di+ t =0.82 *2389.58 +10 =1969.46 mm
ro= 0.15 Di+T =0.15*2389.58 +10=368.437 mm
Do=Di+2t =2389.58 +2*12 =2413.58 mm
Do2/4Ro= 2413.582/(4*1969.46) = 739.46 mm
Sqrt(Do* ro /2)=Sqrt (2413.58*368.437/2)=666.8 mm
ho= 668.8 mm
ho is least.
Therefore hE=ho=668.8 mm
hE/Do=668.8/2413.58 =0.277;
t/Do=10/2413.5 =4.14*10-3.
From graph hE/Do vs C, we have C=1.35t =
=PDoC/200f J= (3.04*10-2*2413.58*1.35)/(200*1*12.6)= 0.091 mm
So, thickness of dome = 0.067mm Shell side fluid is water.
Total Heat removed = 94101140.57 kj/hr
62
Heat removed per tube = (94101140.57*103)/(3600*2194)= 11913.95 W
q = UA∆T, Substituting A=1050.44 m2,∆T=370-298 = 72°K, q = 94101140.57 kj/hr
We have U = 1244.25 W/m2 °C
Internal diameter of vessel = 2413.5 mm
We know that
Ds/5 < baffle spacing < Ds
i.e., 482.7< baffle spacing<2413.5
Use Baffle spacing = 1360 mm
Number of baffles = 4
10.2.5. Design Specifications: Tubes:
Number of tubes: 2194
Length: 4m
Catalyst filled height: 3.8 m
Inside diameter: 31.3 mm
Outside diameter: 38.1 mm
Gauge: BWG 10 number
Heat transfer area: 1050.44 m2
Passes: 1 (flow in upward direction)
Tube Pattern: Triangular Tube Pitch: 47.6 mm
Inlet temperature: 350° C
Outlet temperature: 426.85° C
10.2.6. Shell:
Fluid: water94101140.57 kj/hr=m*4.198*(370-298)
63
Flow: 311.33 Tons/hr
Inlet temperature: 25 °C
Outlet temperature: 96.85 °C
Heat removed per tube: 11913.95W
Heat transfer coefficient: U = 55.29 W/m2 °C
Inside Diameter: 2389.58 mm
Passes: 1
Baffles: 4
Baffle spacing: 1360 mm
10.2.7. Details about construction material:
Type of material: Low alloy steel
Material specification: IS: 3609Grade or designation: 2.5% Cr, 1% Mo
Tensile strength (min): 49 Kg/mm2
Yield stress (min): 25 Kg/mm2
10.2.8. Reactor specifications:
Orientation: Vertical
Operation mode: Continuous
Height: 10 m
Outside diameter: 5498 mm
Class: I
Design Pressure: 3 atm
Wall thickness: 12 mm
Type of Ends: Ellipsoid, 2.5:1
64
End thickness: 10 mm
Man holes: 2 * 450 mm * 400 mm
Catalyst weight:
From literature, wt% of the catalyst=0.05% of Nitrobenzene[7]
Therefore,weight of catalyst=0.0005*40211.40421=20.10 kg of catalyst.
65
Symbols used in design of Cooler:
A - heat transfer area, m2 or ft2
B - baffle spacing, in
cp - specific heat at constant pressure, J/g oC or Btu/lb oF
C- clearance, in
hi -heat-transfer coefficient for inside of tube ,W/m2 oC or Btu/ft2 oF h
hio -heat-transfer coefficient for outside of tube, W/m2 oC or Btu/ft2 oF h
ho - shell side heat-transfer coefficient, W/m2 oC or Btu/ft2 oF h
G - mass velocity, kg/m2 s or lb/ft2h
K -thermal conductivity , W/m oC
LMTD -logarithmic mean temperature difference
PT – tube pitch, in
Q - quantity of heat, J or Btu
Re – Reynolds number
U - overall heat-transfer coefficient, W/m2 oC or Btu/ft2 oF h
66
10.3 DESIGN OF COOLER
Cold Fluid Data:
Inlet Temperature t1=25oC =77oF
Outlet Temperature t2=131o F
Weight flow w=19035.82kg/hr
Hot Fluid data:
Inlet Temperature T1=371.69oK = 209.12oF
Outlet Temperature T2=303.15oK =86o F
Weight flow W=42186.67 kg/hr
i.e 11786.68 kg/hr of water + 30417.99696 kg/hr of aniline
Calculation of ∆TLMTD:
∆T1= 209.12-86 =123.12o F
∆T2= 86-71 =15oF
∆TLMTD = ∆T1-∆T2 / ln(∆T1/∆T2)
= 17.79oF
Calculation of R and S values:
R= (T1-T2)/(t2-t1)
= 2.28
S = (t2-t1)/(T2-t1)
= 0.4
67
Calculation of Correction Factor:
FT is found using LMTD correction factor curves
From Graph we get, FT=0.94
The values of R and S satisfy with Correction factor value for 2-4 shell and tube heat
exchanger.
∆tln = ∆TLMTD*FT
= 17.79*0.94 = 16.72ᴼF
Calculation of UD
From the literature the UD value of middle and heavy organics ranges from 60-90 W/m2K
Assume a value of UD
Let the value of UD be 70 btu/hr ft2
Calculation of heat transfer area
A= Q/ UD*∆t
= 51881745.9/(1.055*70*16.72)
= 4433.3 ft2
Length of the tube L=16’0’’(3/4 in.OD,16BWG)-Square pitch
From the table,
Flow area per tube a’t=0.302in2
Outside area per linear ft a’’=0.1963 ft2
Tube inside diameter D=0.62 in (Obtained from tables)
No. of tubes per shell, Nt= Heat transfer area/(No. of shell side passes* total
surface area)
Nt= 4433.3/(2*16*0.1963)
68
= 705.76
= 706 tubes
For 3/4in.OD on 1-in. Square pitch (from the table),Nearest count(from 706 tubes): 688 tubes
in a 33in.ID shell
Calculation of corrected UD:
Ud,corr = Q/A* ∆ T LMTD.
A= No. of passes * No. of tubes * Length of the tube * Outside area
= 2* 688* 16* 0.1963
=4321.74 ft2
UD = Q/(A*∆T)
=51881745.9/(1.055*4321.74*16.72)
=68.06
Tube side Calculation:
at = Nt * at /(144n)
=688* 0.302/(144*4)
= 0.36 ft2
Mass velocity:
Gt = w/ at
= 42186.67/(0.454*0.36)
= 258117.2 lb/ hr ft2
At Tavg= 64.25ᴼC
µ for aniline water mixture =3.46lb/ft hr
Ret = D*Gt / µ
69
Tube inside diameter = D = 0.62in
= 0.62/12 =0.0517 ft
Ret = 0.0517*258117.2/(3.46)
= 3856.83
j factor for heat transfer curve jH
At L/D = 16/0.0517 =25.8
jH = 4.2 (from graph)
Cp = 0.65 Btu/lb
K = 0.17 Btu/ hr.ft2. ᴼF
hi = jH *(K/D)*(Cµ/K)1/3
= 4.2*(0.17/0.0517)*(0.65*3.46/0.17)1/3
= 32.66
hio= hi * ID/OD
= 32.66 * 0.62/0.75
=27 Btu/hr. ft2.ᴼF
At Re = 3856.83
f= 0.00036, S= 0.7
Tube side pressure drop (∆Pt) = f Gt2 Ln/(5.22*1010*D *S)
∆Pt= 0.00036*258117.22*16*4/(5.22*1010*0.0517*0.7)
=0.81 Psi
For Gt = 258117.2 ,v2/2g = 0.012
Return pressure drop (∆Pr) = 4n/ S*(v2/2g)
= 4*4*(0.012)/0.7 =0.274 psi
70
Total pressure drop (∆PT) = ∆Pt +∆Pr =1.084 Psi
Shell side Calculations:
B= 12in
C = 0.25in
PT = C + Tube OD = 0.25+0.75 =1 in
Flow area as = ID* C*B/(144PT) = (33*0.25*12)/(2*144*1) = 0.343 ft2
Mass velocity :
Gs= W/as = 19035.82/(0.454*0.343) = 121975.61 lb/ hr.ft2
T avg= 40ᴼC
µ = 0.7 Cp = 1.6933 lb/ft. hr
Res = De* Gs/µ
De =0.95/12 = 0.0792 ft
Re = (0.0792*121975.61)/1.6933 =5705.11
jH =37
K = 0.609 W/ m.K
= 0.352 btu/hr. ft2.ᴼF
ho = jH* K/ D*(Cµ/K)1/3
= 37*0.352/0.0792*(1*1.6933/0.609)1/3
= 231.23 btu/hr. ft2.ᴼF
f = 0.0026, S= 0.72
No. of Crosses N+1 = 12L/ B
= 12*16*2/12
= 32
71
Shell diameter Ds= 33/12
= 2.75 ft
Shell side pressure drop
∆Ps = f Gs2Ds(N+1)/(5.22*1010*0.079*0.72)
= 1.14 Psi
Clean overall Coefficient Uc:
Uc = hi0* h0/(hi0+h0)
= 80.4 btu/hr.ft2.ᴼF
Dirt Factor Rd :
Rd = UC- UD/( UC*UD)
=2.255*10-3 hr.ft2.ᴼF/ btu
72
Specification sheet of Cooler
Item
Heat Exchanger
Type
2-4 shell & tube
Operation
Continuous
Inlet temp. processing stream
209.12 °F
Outlet temp. processing temp.
86 °F
LMTD
17,79 °F
UC
68.06 Btu /hr. ft2.°F
UD
80.4 Btu /hr. ft2.°F
No.of tubes
688
Pressure drop shell side
1.14 psi
Pressure drop tube side
1.084 psi
Heat transfer area
4321.74 ft2
Length of the tube
16 ft
Tube inner dia
0.0517 ft
Tube outer dia
0.0625 ft
Shell inner dia
1.9375 ft
Pitch
1 inch (square)
Baffle spacing
1 ft
No of baffles
16
73
Symbols used in the design of the Distillation column:
x = mole fraction of water in liquid phase
y = mole fraction of water in gas phase
ᵧ1 =activity coefficient of water in liquid phase
xD = mole fraction of water in distillate
R = reflux ratio
Rm =minimum reflux ratio.
Roptimum= optimum reflux ratio
ρv1= density of the vapour
ρL1, ρL2 =Density of the liquid
M1 =average molecular weight
T =Boiling temperature
S1, S2 =Cross sectional area
Q =vapour rate
q =Liquid rate
An =Net tower cross sectional area
W=Weir length
Aw =tray area used by one downspout
T =Tower diameter
Ad =Downspout cross sectional area
h1 =Weir crest
hw =weir height
hD =Dry pressure drop
74
A0=area of one sieve
V0= velocity through orifice
µG =Viscosity of gas
NRo =Sieve Hole Reynolds number
f =fanning friction factor
hL =Hydraulic head:
hR =Residual pressure drop
hG =Total gas pressure drop
h2=Pressure loss at liquid entrance
Ada =the area for liquid flow under apron
t = tray spacing
75
10.4 DESIGN OF DISTILLATION COLUMN - 2
Feed to the distillation column: Water = 5147.21291 kg/hr
Aniline=31750.37067 kg/hr
Top product from Distillation column consists of 78.61 wt% of water.
Bottom product from Distillation column consists of 0.097 wt% of water.
10.4.1. Material balance:
Feed:
Moles of water in feed=5147.21291/18.0152=285.715 kmol/hr
Moles of Aniline in feed=31750.37067/93.1262=340.939 kmol/hr
Mole fraction of Water in feed=285.715/(285.715+340.939)=0.456
Total moles of feed=626.654 kmol/hr
Distillate:
Aniline in top product =1392.55056kg/hr
Water in top product=5117.73724 kg/hr
Moles of water in distillate=5117.73724/18.0152=284.079 kmol/hr
Moles of Aniline in distillate=1392.55056/93.1262=14.953 kmol/hr
Mole fraction of water=77.299/(77.299+54.955)=0.95
Total moles of distillate=299.032
Bottom:
Aniline=30387.29578 kg/hr
Water=29.47567 kg/hr
Moles of aniline in bottom product=30387.29578/93.1262=326.302 kmol/hr
Moles of water in bottom product=29.47567/18.0152=1.636 kmol/hr
76
Mole fraction of water in bottom product=1.636/ (1.636+326.302) =0.005
Total moles in bottom=327.938 kmol/hr
10.4.2. Vapour-liquid equilibrium data:
Equilibrium data for Water and Aniline mixture at 743mm of HgTable 16:
T0C
X
ᵧ1
y
44.94
0.314
2.999
0.957
898.87
55.38
0.236
3.220
0.935
110
1066.02
67.81
0.197
3.272
0.96
115
1258.05
82.51
0.1599
3.275
0.888
120
1477.74
99.81
0.136
3.253
0.881
125
1727.98
120.03
0.1128
3.21
0.843
130
2011.91
143.65
0.0948
3.164
0.814
135
2332.81
171.0
0.0795
3.115
0.779
140
2694.18
202.58
0.0663
3.065
0.738
145
3099.68
238.79
0.0548
3.017
0.691
150
3553.18
280.24
0.0446
2.971
0.635
155
4058.68
327.46
0.0357
2.928
0.572
160
4620.43
381.05
0.0277
2.887
0.498
165
5242.82
441.64
0.0207
2.849
0.147
170
5930.4
509.9
0.0143
2.814
0.322
175
6687.9
586.53
0.00862
2.781
0.216
180
7520.23
672.29
0.00348
2.750
0.097
P1sat(mm of
P2sat(mm of
Hg)
Hg)
100
754.05
105
10.4.3. Ideal stages using Mc-Cabe-Thiele’s method
Feed is vapour at its dew point:
So, q-line is passing through x=y=0.456 with slope zero i.e is horizontal.
q-line meets equilibrium curve at y=0.46 & x=0.02.
Operating line for the enriching section pass through x=xD= y=0.95 and y=0.46 & x=0.02.
77
It intersects the Y-axis at y=0.45
So, xD/(Rm+1)=0.45,Rm=1.11 where Rm is minimum reflux ratio.
Roptimumis 1.2 to 1.5 times of Rm.
R=1.5*1.11=1.665
Then, Y-intercept for enriching section operating line=xD/(R+1) = 0.35
And this operating line meets the q-line at x=0.165 and y=0.46
The operating line for stripping section is drawn from above point to x=y=xD= 0.005.
So, no of ideal or theoretical stages=3.
10.4.4. Actual trays using efficiency of tray
Viscosity of water = 0.282 cP
Viscosity of Aniline = 1.5 cP
Average viscosity=0.282*0.46+1.5*.54=0.9397=18.66%
So, efficiency =18.66%
No. of ideal stages/no. of real stages = efficiency
No. of real stages= 2/0.1866 = 10.71 = 11.
10.4.5. Ideal feed tray location using Mc-Cabe-Thiele diagram
Feed is introduced between 1 and 2 tray.
From the diagram, feed plate is the 1.18th plate
10.4.6. Actual feed tray location using efficiency of plate
Feed location=1.18/.1866=6.32, so feed is introduced between 6 and 7.
No. of real stages in stripping section=5
No. of real stages in enriching section=6
78
10.4.7. The height of the column using thumb rule of plate spacing and the number of
actual plates
Plate spacing=60 cm
No. of total stages=11
With one extra plate spacing at feed tray and One each above the topmost and Below the
bottom-most tray.
Column height=13*60=7.8 m.
Moles of vapour at the top of the column:
R= L/D so L=R*D;
V1= L+D = R*D+D = (R+1)*D = (1.665+1)*299.092=797.08 kmol/hr
Moles of vapor at the bottom of the column:
V2=797.08-626.654=170.426 kmol/hr.
10.4.10. Boiling temperature, average molecular weight, density of the vapour and
density of the liquid at the top and the bottom of the column
Top:
T1=∑x*T=(184.4*0.05+100*.95)=95.92 C=369.07 K
M1= ∑x*M=(93.1262*0.05+18.0152*0.95)=21.77
ρv1=PM/RT=743821.77/(760*0.08205*369.07)=0.703 kg/m3=0.0323 kmol/m3
Bottom:
T2=∑x*T=(184.4*0.995+100*.005)=183.978C=457.13K
M2=∑x*M=(93.1262*.995+18.0152*.005)=92.75
ρ v2=PM/RT=2.4175 kg/m3=0.026 kmol/m3
Density of the liquid = (x1* ρL1 )+ ( x2* ρL2)
=0.995*1021.7+0.005*971.8=1021.45 kg/m3.
79
Density of the liquid=ρL1=ρL2=1021.45 kg/m3(assume density of the liquid does not change
much with temperature as that of vapor).
10.4.11. Vapour velocity & Cross sectional area of the column at the top and the bottom
Vapour velocity
Where Kv=0.05
Mass flow rate(m)=ρus ⇒s=(П/4)×D2 =m/ρu
Top:
(u1)=K1*(( ρL- ρv1)/ ρv1)0.5=1.905m/sec=6858 m/hr
S1=V1/ (u1* ρ v1)= 797.08/(6858*0.0323)=3.6 m2.
Bottom:
(u2)=K2*(( ρL- ρv2)/ ρv2)0.5=1.027 m/sec=3697.2 m/hr
S2=V2/ (u2* ρ v2)= 170.426/(3697.2*0.026)=1.772 m2
So, higher cross sectional area S1 is used for further calculations.
10.4.12.Diameter of the column
Enriching section [4]:
ρ v1=0.703 kg/m3=0.0323 kmol/m3
Vapor rate Q=V1/molar density=797.08/(0.0323*3600)=6.855 m3/s.
ρL2=1021.45 kg/m3
Liquid rate q=327.938 kmol/hr*92.75/1021.45=8.3*10-3 m3/s
Net tower cross sectional area An=3.6 m2
80
Tentatively choose a weir length W=0.7T. Table 6.1[4]:the tray area used by one
downspout=8.8%
At=3.6/(1-0.088)=3.947 m2
Tower diameter T=(4*At/π)0.5=(4*3.947/π)0.5=2.242 m, say 2.24 m
Corrected At = πT2/4 = π2.242/4 = 3.94 m2.
W = 0.7*T = 0.7*2.24 = 1.568 m
Downspout cross sectional area Ad=0.088*3.94=0.3467 m2
For the design area taken by tray support + disengaging and distributing zones [4]=0.222m2.
Active perforated area Aa=At-2*Ad-0.222=3.94-2*0.3467-0.222=3.0246 m2
q/W=6.26*10-3 m3/m.s is ok.
Weir crest h1 and weir height hw:
Let h1=25mm=0.025 m.h1/T=0.025/2.24=0.011
T/W=1/0.7=1.429
Eq:6.34[4]:Weff/W=(1.4292-((1.4292-1)0.5+2*0.011*1.429)2)0.5=0.967
Eq.6.33 [4]:h1=0.666(6.26*10-3*0.967)2/3=0.0207m
So take h1=0.0207m, h1/T=0.0207/2.24=0.0092
T/W=1/0.7=1.429
Eq:6.34[4]:Weff/W=(1.4292-((1.4292-1)0.5+2*0.0092*1.429)2)0.5=0.972
Eq.6.33 [4]:h1=0.666(6.26*10-3*0.972)2/3=0.0206m.is ok
So, final h1=0.0207m.
Set weir height haw=50mm=0.05m.
Dry pressure drop hD:
Eq.6.37 [4]c0=1.09*(d0/l)0.25=1.09*(0.0045/0.002)0.25=1.335
81
A0=0.0555*Aa=0.0555*3.0246=0.1679 m2.
V0=Q/A0=6.855/0.1679=40.83 m/s.
Viscosity of gas is taken as µG=0.012cP=1.25*10-5 kg/m.s
Hole Reynolds number [4] =d0*V0* ρ v1/ µG=0.0045*40.83*0.703/1.25*10-5=10333.5
So, fanning friction factor for NRe=10333.5 is f=0.0075,g=9.807 m2/s,l=.002l.Eq.6.36,
hD=0.1096
Hydraulic head hL:
Va=Q/Aa=6.855/3.0246=2.266 m/s.
Z=(T+W)/2=(2.24+1.568)/2=1.904 m
Eq 6.38:hL=0.0209 m
Residual pressure drop hR Eq.6.42 [4]:hR=(6*0.04*1)/(1021.42*0.0045*9.807)=0.00532 m
Total gas pressure drop hG:
Eq.6.35 [4]:hG=hD+hL+hR=0.1096+0.0209+0.00532=0.13582 m
Pressure loss at liquid entrance h2:
The area for liquid flow under apron =0.025*W=0.025*1.568=0.0392 m2.
Since this is smaller than Ad,Ada=0.0392 m2.
Eq. 6.43[4]:h2= (q/Ada) 2*1.5/g= (0.00827/0.0392)2*1.5/9.807=0.00681 m.
Backup in downspout: Eq.6.44 [4]; h3=hG+h2=0.13582+0.00681=0.14263 m.
Check on flooding: hW+h1+h3=0.05+0.025+0.14263=0.21763 m
For tower diameter T between 1 and 3 m, tray spacing t=0.60m.
hW+h1+h3=0.21763, which is well below t/2=0.30m.
Therefore the chosen t is satisfactory.
82
Weeping velocity: for W/T=0.7, the weir is set 0.3296T=0.738 m from the centre of the
tower. Therefore Z=2*0.738=1.476 m.
All other quantities in Eq 6.46 have been evaluated and then the equation yields VOW=7.47
m/s.
The tray will not weep excessively until the gas velocity through the holes V0 is reduced ti
close to this value.
Entrainment:
ρv1=0.703 kg/m3=0.0323 kmol/m3
vapour rate Q=V1/molar density=797.08/(0.0323*3600)=6.855 m3/s.
ρL2=1021.45 kg/m3
Liquid rate q=327.938 kmol/hr*92.75/1021.45=8.3*10-3 m3/s
L’=q* ρL=0.0083*1021.45=8.478 kg/s
G’=Q* ρ v1=6.855*0.703=4.819 kg/s
V/VF=0.8, (ρ v1/ ρL)0.5*L’/G’=0.046
Fig 6.17: E=0.07.The recycling of liquid resulting from such entrainment is too small to
influence the tray hydraulics appreciably.
Stripping Section:
ρ v2=PM/RT=2.4175 kg/m3=0.026 kmol/m3
M2=∑x*M=(93.1262*.995+18.0152*.005)=92.75
V2=797.08-626.654=170.426 kmol/hr.
Q=170.126/(3600*0.026)=1.82 m3/s
ρL2=1021.45 kg/m3
Liquid rate q=327.938 kmol/hr*92.75/1021.45=8.3*10-3 m3/s
83
Net tower cross sectional area An=1.772m2
Tentatively choose a weir length W=0.7T. Table 6.1[4]:the tray area used by one
downspout=8.8%
At=1.772/(1-0.088)=1.943 m2
Tower diameter T=(4*At/π) 0.5=(4*1.943/π)0.5=1.573 m, say 1.57 m
Corrected At=πT2/4= π1.572/4=1.936 m2.
W=0.7*T=0.7*1.57=1.099 m
Downspout cross sectional area Ad=0.088*1.936=0.1704 m2
For the design area taken by tray support + disengaging and distributing zones=0.222m2.
Active perforated area [4] Aa=At-2*Ad-0.222=1.936-2*0.1704-0.222=1.3732 m2
q/W=7.55*10-3 m3/m.s is ok.
Weir crest h1 and weir height hw:
Let h1=25mm=0.025 m.h1/T=0.025/1.57=0.016
T/W=1/0.7=1.429
Eq:6.34[4]:Weff/W=(1.4292-((1.4292-1)0.5+2*0.011*1.429)2)0.5=0.951
Eq.6.33 [4]:h1=0.666(7.55*10-3*0.951)2/3=0.0265m
So take h1=0.0265 m, h1/T=0.0265/1.57=0.0169
T/W=1/0.7=1.429
Eq:6.34[4]:Weff/W=(1.4292-((1.4292-1)0.5+2*0.0169*1.429)2)0.5=0.948
Eq.6.33 [4]:h1=0.666(7.55*10-3*0.972)2/3=0.0266m.is ok
So, final h1=0.0265m.
Set weir height hw=50mm=0.05m.
84
Dry pressure drop hD:
Eq.6.37 [4]c0=1.09*(d0/l)0.25=1.09*(0.0045/0.002)0.25=1.335
A0=0.0555*Aa=0.0555*1.3732=0.0762 m2.
V0=Q/A0=1.82/0.0762=23.88 m/s.
Viscosity of gas is taken as µG=0.012cP=1.25*10-5 kg/m.s
Hole Reynolds number=d0*V0* ρ v1/ µG=0.0045*23.88 *2.4175 /1.25*10-5=18473.57
So, fanning friction factor for NRe=10333.5 is f=0.0065,g=9.807 m2/s,l=.002l.Eq.6.36[4],
hD= 0.133 m
Hydraulic head hL:
Va=Q/Aa=1.82/1.3732=1.333 m/s.
Z= (T+W)/2= (2.24+1.568)/2=1.3345 m
Eq.6.38:hL=0.0253 m
Residual pressure drop hR Eq.6.42 [4]:hR= (6*0.04*1)/(1021.42*0.0045*9.807)=0.00532 m
Total gas pressure drop hG:
Eq.6.35 [4]:hG=hD+hL+hR=0.133+0.0253+0.00532=0.16362 m
Pressure loss at liquid entrance h2:
The area for liquid flow under apron =0.025*W=0.025*1.568=0.0275 m2.
Since this is smaller than Ad,Ada=0.0275 m2.
Eq. 6.43[4]:h2= (q/Ada) 2*1.5/g= (0.00827/0.0275)2*1.5/9.807=.0139 m.
Backup in downspout: Eq.6.44; h3=hG+h2=0.16362 +.0139 =0.1775 m.
Check on flooding: hW+h1+h3=0.05+0.0265+0.1775 =0.254 m
For tower diameter T between 1 and 3 m, tray spacing t=0.60m.
hW+h1+h3=0.254, which is well below t/2=0.30m.
85
Therefore the chosen t is satisfactory.
Weeping velocity: for W/T=0.7, the weir is set 0.3296T=0.517 m from the centre of the
tower. Therefore Z=2*0.517=1.034 m.
All other quantities in Eq.6.46 have been evaluated and then the equation yields VOW=2.901
m/s.
The tray will not weep excessively until the gas velocity through the holes V0 is reduced ti
close to this value.
Entrainment:
ρ v2=PM/RT=2.4175 kg/m3=0.026 kmol/m3
M2=∑xM=(93.1262*.995+18.0152*.005) =92.75
V2=797.08-626.654=170.426 kmol/hr.
Q=170.126/(3600*0.026) =1.82 m3/s
ρL2=1021.45 kg/m3
Liquid rate q=327.938 kmol/hr*92.75/1021.45=8.3*10-3 m3/s
L’=q* ρL=0.0083*1021.45=8.478 kg/s
G’=Q* ρ v1=1.82*2.4175=4.4 kg/s
V/VF=0.8, (ρv2/ ρL)0.5*L’/G’=0.094
Fig 6.17: E=0.042.The recycling of liquid resulting from such entrainment is too small to
influence the tray hydraulics appreciably.

The minimum column diameter for tray columns is typically 0.75 m; otherwise, packed
columns are used.

The maximum diameter of the column can be quite large – up to 5 m – although it may be
decided to operate 2 or more separate columns in place of an otherwise large diameter
single column.
86

As the column diameter decreases, the vapour velocity increases for a given vapour flow
rate.

The minimum column diameter is based upon the maximum vapour velocity that causes
excessive entrainment and flooding.

The maximum column diameter is based upon maintaining a high enough velocity to
prevent excess weeping.

The operating vapour velocity, and hence actual column diameter, is specified as a
fraction of the flooding vapour velocity – typically 0.65 to 0.90.

The final consideration is column cost – a larger diameter column is more expensive than
a smaller diameter column, although economies of scale enter
87
11. COST ESTIMATION AND ECONOMICS
An acceptable design must present a process that is capable of operating under conditions
which yields profit. Capital must be allocated for the direct plant expenses such as those for
raw materials, labour and equipment. Besides direct expenses many other indirect
expenses are also incurred e.g. administration, salaries, product distribution cost, cost for
interplant communications.
A capital investment is required for any industrial process and determination of necessary
investment for any process consists of fixed capital investment for physical equipment and
facilities in the plant plus working capital which must be available to pay the salaries keep
raw materials and products on the hand and handle other specified items required a direct
cash outlay.
Thus in analysis of cost in industrial processes, capital investment cost, manufacturing costs
and general expenses including income taxes must be taken into consideration. Here method
chosen is the annual cost method because of the following advantages:
1. Effects of seasonal variations are soothed out.
2. Plant on stream time or equipment operating factor is considered.
3. It permits more rapid calculation of operating cost at less than full capacity.
4. It provides a convenient way of considering infrequently occurring but large expenses such
as annual turn around cost.
Cost of producing aniline per annum in 2002 = $ 5.5x106
Chemical plant index for the year 2002 = 76.2
Chemical plant index for the year 2012 = 402
Therefore cost of plant in 2012 =
Cost in 2002x {(cost index in 2012)/ (cost index in 2002)}
= 5.5x106 (402/76.2) = $ 29.016x106
Or Rs. 143.63 crores (1$ = 49.5 Rs)
Therefore fixed capital cost = FCC = Rs 143.63 crores
Total capital investment = TCI = FCC + Working capital
Working capital = 25% of TCITherefore working capital = Rs 179.54 crores
88
DISTRIBUTION OF CAPITAL COST Table 17:
INDIRECT COST % Of FCC COST (crores of Rs.) Table-18:
ESTIMATION OF TOTAL PRODUCT COST
Let X be the total product cost
Distribution of total product cost
89
DIRECT PRODUCTION COST COST (In Crores) Table-19:
FIXED CHARGES COST (In Crores) Table-20:
Fixed charge = 16% of TPC (let)
20.1082 + 0.07125X = 0.16X
X = 226.57 crores
GENERAL EXPENSES Table-21:
90
Total product cost = manufacturing cost + general expenses
= (30.1082 + 0.76875X) + 0.2375X
= 30.1082 + 1.00625X
X = 226.57 crores
Therefore general expenses = 53.4 crores
Therefore manufacturing cost = 204.2 crores or Direct production cost
BREAKEVEN ANALYSIS:
Breakeven point occurs when the total annual product cost equals the total annual sales. The
total annual product cost is the sum of the fixed cost (including fixed charges, Overhead and
general expenses) and direct production cost for ‘n’ units per year. The total annual sale is the
product of the number of units and the selling price per unit.
Cost price of aniline per kg = 226.57x107/1x107 = 226.57 or Rs. 227
Assuming a profit margin of 10% so selling price of the product = Rs. 250
Gross annual earnings = total annual sales – total annual product cost = Rs. 23 crores
Net annual earnings = gross annual earnings – income tax = 23 – 40% of 23 =Rs. 13.8 crores
Pay back period = Total capital investment / Net annual earnings
= 179.54/ 13.8 = 13 years (approx)
Rate of return = Net profit / FCC
= 13.8/143.6
= 9.6%
91
12. PLANT LOCATION AND LAYOUT
PLANT LOCATION AND SITE SELECTION:
The location of the plant can have a crucial effect on the profitability of a project and the
scope for future expansion. Many factors must be considered must be considered when
selecting a suitable site. The factors to be considered are:
1. Raw Material Supply
2.
Location with respect to the marketing area
3. Transport facilities
4. Availability of Labour
5. Availability of Utilities: Water, fuel an Power
6. Availability of Land
7. Environmental Impact and Effluent Disposal
8. Climate
9. Taxation and legal restrictions
10. Flood and Fire Protection
11. Local Community Considerations
RAW MATERIALS:
The availability and price of suitable raw material often determine the site of location of the
plant.In this project nitrobenzene is the major raw material and produced in major quantities
by nitration of benzene Approximately 95% of nitrobenzene is consumed in the production
of aniline which is a precursor to rubber chemicals, pesticides, dyes,explosives,
and pharmaceuticals.Nitrobenzene is also used in shoe and floor polishes, leather dressings,
paint solvents, and other materials to mask unpleasant odours. Redistilled, as oil of mirbane,
nitrobenzene has been used as an inexpensive perfume for soaps. A significant merchant
market for nitrobenzene is its use in the production of the analgesic paracetamol
MARKETING AREA:
The location of market or intermediate distribution centres affects the cost of product
distribution and the time required for shipping. Proximity to the major markets is an
important consideration in the selection of plant site, because the buyer usually finds it it
92
advantage to purchase from nearby sources. The closer the market, The lesser will be the
transportation cost and the easier will be the access to the products by the buyers.
TRANSPORTATION FACILITIES :
The transport of material and product to and from the plant will be an overriding
consideration in the site selection .Here the site should be chosen so as to be closed to at least
two major forms of transport : road, rail, waterway (canal and river ) or a sea port. Road and
rail transport is being increasingly used, and is suitable for long distance transport of bulk
chemicals like aniline Air transport is convenient and efficient for the movement of personnel
and essential equipment and supplies and the proximity od the site airpot should be
considered.
AVAILABILITY OF LABOUR:
Labour will be needed for construction of the plant and its operation. Skilled construction
workers will be usually be brought in from outside the site area, but there should be an
adequate pool of unskilled labour available locally and labour suitable for the training to
operate the plant. Skilled tradesman will be needed for plant maintenance. Local trade union
customs and restrictive practices will have to be considered when assessing the availability
and suitability of the local labour for recruitment and training. Apart from this consideration
should be given to the pay rates, restrictions on the number of hours, raial problems and
variations in the skills and intelligence of the workers.
UTILITIES (SEVICES):
Chemical processes invariably require large quantities of water for cooling and general
process use and therefore, the plant must be located near a source of water of suitable
quantity. Process water may also be drawn from river, from wells, or purchased from a local
authorities. In some sites the cooling water required can be taken from a river or lake, or from
the sea: at other location cooling tower will be needed. Hence , the plant should be located
near a lake, or sea.
Apart from this electrical power is also needed in large quantities and hence, location of
plant near hydroelectric installations should be considered. A competitive priced fuel should
also be looked for near or on site for steam and power generation.
93
LAND (SITE SELECTION):
The plant location should be chosen such that sufficient suitable land is available for the
proposed plant and also for future expansions. The land should be ideally flat, well drained
and have suitable load bearing characteristics. A full site evaluation should be made be taken
into consideration in order to determine the need of piling or other special formations.
ENVIRONMENT IMPACT AND DISPOSAL:
All industrial processes produce waste products and full consideration must give to the
difficulties and cost of their disposal. The disposal of toxic and harmful effluent should be
done following the local waste disposals regulation and also, the appropriate authorities must
be consulted during the initial site survey to determine the standards that must be met.
CLIMATE:
Adverse climate conditions at a site will increase cost. Abnormally low temperatures will
required the provision of additional insulation and special heating for equipment and pipes
runs. Stronger structure will be needed at locations which are subjected to high winds
(cyclone and hurricanes areas) or earthquake. Hence, the effect of humidity and temperatures
at the site must be taken into consideration because it affects the economics evaluations of the
projects.
TAXATION AND LEGAL RESTRICTIONS:
Capital grants, tax concession and other inducement are often given by government to direct
renewed investment to preferred locations, such as areas of high unemployment. The
availability of such grants can be the overriding consideration in site selection.
FLOOD AND FIRE PROTECTION:
Before choosing be examined. The regional history of natural events like floods and
hurricane damage should be examined. In case of major fire they should be provision for fire
assistance from outside the fire department.
LOCAL COMMUNITY CONSIDERATION:
94
Cultural facilities foe the communities are the important for the sound growth. The proposed
plant must fit in with and be acceptable to the local community. Full consideration must be
given to the safe location of the plant so that it does not impose a significant additional rest to
the community. On a new site , the local community must be able to provide adequate
facilities for the plant personnel; school, banks, housing and recreational and cultural
facilities.
Considering all the above factors the aniline plant should be located at a place where:
1.
The road and the rail transport system is easily available.
2.
Since Nitrobenzene does not occur naturally in the environment. It is produced
industrially by reacting benzene with sulphuric acid, nitric acid and water. As it is
major raw material for production of aniline . So, plant site should be nearer to a
industries which produce nitrobenzene in order to avail the raw material cheaply.
3.
Aniline used in a variety of applications; rubber processing chemicals
(9%), herbicides (2%), and dyes and pigments (2%).[5]As additives to rubber, aniline
derivatives. Hence plant should be located to a place where aniline can be easily
consumed.
1
1
1
95
8
1
3
2
10
0
5
9
7
2
4
11
3
1. TANK FARM
2. PLANT AREA
3. EXPANSION
4. PLANT UTILITIES
5. STORES
6. FIRE STATION
7. CANTEEN
8. EMERGENCY WATER
9. LABORATORY
10. WORK SHOP
11. OFFICE
96
13. POLLUTION CONTROL AND SAFETY
Aniline:
Aniline is a clear to slightly yellow liquid with a characteristic odour. It does not readily
evaporate at room temperature. Aniline is slightly soluble in water and mixes
readily with most organic solvents .Aniline is used to make a wide variety of products such as
polyurethane foam, agricultural chemicals, synthetic dyes, antioxidants, stabilizers for the
rubber industry, herbicides, varnishes and explosives.
Potential health effects:
Aniline can be toxic if ingested, inhaled, or by skin contact. Aniline damages haemoglobin , a
protein that normally transports oxygen in the blood. The damaged haemoglobin cannot carry
oxygen. This condition is known as met hemoglobinemia and its severity depends on how
much you are exposed to and for how long. Met haemoglobinemia is the most prominent
symptom of aniline poisoning in
humans, resulting in cyanosis (a purplish blue skin color) following acute high exposure to
aniline. Dizziness, headaches, irregular heart beat, convulsions, coma, and death may also
occur. Direct contact with aniline can also produce skin and eye irritation. Long-term
exposure to lower levels of aniline may cause symptoms similar to those experienced in acute
high-level exposure. There is no reliable information on whether aniline has adverse
reproductive effects in humans. Studies in animals have not demonstrated reproductive
toxicity for aniline.
The available studies in humans are inadequate to determine whether exposure to aniline can
increase the risk of developing cancer in people. Rats that ate food
contaminated with aniline for life developed cancer of the spleen. The International Agency
for Research on Cancer (IARC) determined that aniline is not classifiable as to its
carcinogenicity to humans. The EPA has determined that aniline is a probable human
carcinogen.
97
SAFETY DATA SHEET OF ANILINE:
This Product Safety Summary is intended to provide a general overview of the chemical
substance. The information on the Summary is basic information and is not intended to
provide emergency response information, medical information or treatment information.
Product Overview :
Pure aniline is a highly poisonous, oily, colorless liquid with a somewhat unpleasant odor of
rotten fish and also has a burning aromatic taste.
Aniline is of great importance in the dye industry, being used as the starting substance in the
manufacture of many dyes-e.g., indigo-and as an aid in the manufacture of others. It is also
used to make chemicals used in producing rubber, urethane foams, explosives, herbicides and
fungicides. Aniline is prepared commercially by the reduction of nitrobenzene, a product of
coal tar, or by heating chlorobenzene with ammonia in the presence of a copper catalyst.
May be fatal if swallowed, inhaled or absorbed through skin. Causes irritation to the skin,
eyes and respiratory tract. Combustible liquid and vapor. May cause methemoglobinemia.
Affects blood, cardiovascular system, central nervous system, liver and kidneys.
Airborne limits have been established for aniline in the work environment. The American
Conference of Governmental Hygienist (ACGIH) has a threshold limit value (TLV) of 5 ppm
for an eight hour time weighted average basis with a skin notation. The Occupational Health
and Safety Administration (OSHA) has established a permissible exposure limit (PEL) of 2
ppm for an eight hour time weighted average basis with a skin notation, also.
For further safety and health information, the current Material Safety Data Sheet (MSDS)
should be used for this substance
Health Information :
Aniline is a potentially hazardous material. A through knowledge of potential dangers, with
strict adherence to recommended safety practices, is essential before aniline products are
handled, stored or used. Workers must be properly instructed and supervised in the handling
of aniline. Limits have been established for allowable concentrations in the work
environment. ACGIH has a threshold limit value (TLV) of 2 ppm for an eight hour timeweighted average basis with a skin notation, while OSHA has set a permissible exposure
limit (PEL) of 5 ppm for an eight hour time-weighted average basis with a skin notation, also.
Effects on the Respiratory System:
98
Exposures to mists or vapor at levels above the recommended exposure limits can produce
eye, nose or lung irritation. Symptoms may include bluish discoloration of lips and tongue,
severe headache, nausea, confusion, dizziness, shock, respiratory paralysis, death. Aniline
affects the ability of the blood to carry oxygen.
Effects on the Skin:
Aniline may be absorbed through the skin. Symptoms of skin absorption parallel those from
inhalation exposure. May cause skin irritation and local contact may cause dermatitis.
Effects on the Eyes:
Aniline vapor is an eye irritant. May cause tearing and blurred vision. Splashes may cause
corneal damage.
Effects of Ingestion:
Aniline is toxic. Lethal doses may be as little as one gram. Symptoms of ingestion parallel
those of inhalation exposure.
Chronic Hazards:
Aniline is a blood toxin, causing hemoglobin to convert to methemoglobin, resulting in
cyanosis. Lengthy or repeated exposures may result in decreased appetite, anemia, weight
loss, nervous system affects, and kidney, liver and bone marrow damage. Any exposure may
cause an allergic skin reaction.
Environmental Information :
When released into the soil, this material is expected to readily biodegrade. When released
into the soil, this material may leach into the groundwater but may evaporate to a moderate
extent. When released into the water, this material is expected to readily biodegrade and have
a half life between 10 and 30 days. Aniline has been experimentally-determined bioconcentration factor (BCF) of less than 100. It is not expected to significantly bioaccumulate.
When released into the air, aniline is expected to readily degrade by reaction with photo
chemically produced hydroxyl radicals and expected to degrade by photolysis. The half life
of aniline in air is less than one day.
Aniline is expected to be very toxic to terrestrial and aquatic life. The LC50/96 hour values
for fish are between 10 and 100 mg/l. The EC50/48 hour values for daphnia are less than 1
mg/l. The inhibition of the degradation activity of activated sludge is not anticipated when
introduced to biological treatment plants in appropriate low concentrations.
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FIRE AND EXPLOSION DATA:
Flammability of the Product: Combustible.
Auto-Ignition Temperature: 615°C (1139°F)
Flash Points: CLOSED CUP: 70°C (158°F).
Flammable Limits: LOWER: 1.3% UPPER: 23%
Products of Combustion: These products are carbon oxides (CO, CO2), nitrogen oxides
(NO, NO2...).
Fire Hazards in Presence of Various Substances:
Flammable in presence of open flames and sparks, of heat. Non-flammable in presence of
shocks.
Explosion Hazards in Presence of Various Substances:
Risks of explosion of the product in presence of mechanical impact: Not available. Risks of
explosion of the product in
presence of static discharge: Not available.
Fire Fighting Media and Instructions:
SMALL FIRE: Use DRY chemical powder. LARGE FIRE: Use water spray, fog or foam. Do
not use water jet.
Special Remarks on Fire Hazards:
Ignites on contact with sodium peroxide + water. Aniline ignites spontaneously in presence
of red fuming nitric acid. Sodium
peroxide or potassium peroxide is spontaneouly flammable with aniline. When heated to
decomposition it emits toxic fumes.
Special Remarks on Explosion Hazards:
Spontaneously explosive reactions occur with benzenediazonium -2-carboxylate, dibenzoyl
peroxide, fluorine nitrate, nitrosyl
perchlorate, red fuming nitric acid, peroxodisulfuric acid, and tetranitromethane. Addition of
a drop of aniline to 1 gram of
dibenzoyl peroxide leads to mildly explosive decompostion after a short delay. Addition of
aniline to nitromethane renders it
susceptible to initiation by a detonator. Anililne reacts with perchloric acid, and then
formaldehyde to produce explosive and combustible condensed resin.
100
14. BIBLIOGRAPHY
1. Kirk Othmer Chemical Engineering Encyclopaedia Vol 02.
2. Reactant Separation from a Pharmaceutical Waste Stream Written by Larke Jo Ernlund Nielsen,
c971547, Department of Chemical Engineering Technical University of Denmark July 4th 2003
3. Process Heat Transfer by Donald Q. Kern,1965.
4. Mass transfer operations, Third Edition, Robert E.Treybal,1981.
5. Perry’s Chemical Engineers’ Handbook, Robert H. Perry, Don W. Green, James O. Maloney, Seventh
Edition 1997.
6. Introduction to Chemical Engineering Thermodynamic Smith sixth edition.
7. Fundamentals of Mass Transfer and Kinetics for the Hydrogenation of Nitrobenzene to Aniline by
Reinaldo M. Machado, Air Products and Chemicals, Inc. No. 01-2007.
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