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PRODUCTION OF
ACRYLONITRILE BY
AMMOXIDATION OFPROPYLENE
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GROUP MEMBERS
Waheed Ahmed
(2k11-ChE-09)
Adnan Rafi
(2k11-ChE-16) Ahmed Haroon
(2k11-ChE-23)
Shahzad Ali Zahid
(2k11-ChE-49)
1a
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CONTENTSIntroductionProcess DescriptionSite SelectionHazop study and EIA
1b
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Introduction
Waheed Ahmad
(2k11-Che-09)
2a
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INTRODUCTION
It was first prepared in 1893 by the French
chemist Charles
Chemical Formula C3H3N.
This pungent-smelling colorless liquid It ismonomer for the manufacture ofplastics.
It produce toxic combustion products
2b
http://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Monomer
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PHYSICAL PROPERTIES
colorless liquid and faint characteristic odor.
Other trade names.
Acrylonitrile polymerizes explosively.
3b
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Property Value
Molecular weight 53.06Boiling point,0C 77.3 At 103.3 kPa
Critical temperature,0C
246.0
Density, g/L 806.0 At 20"C
Explosive limit at 250C, vol
%
3.05-17.0
Flash point0C -5
Freezing point,0C -83.55
Heat of polymerization,kJ/mol
-72.4
Ignition temperature, °C 481.0
Viscosity at 25°C, cP 0.34
Heat capacity, 2.094
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CHEMICAL PROPERTIES
Reactions of the Nitrile Group
Hydration and Hydrolysis
Alcoholysis
NH-HX
CH2=CHCN + ROH + HX XCH2CH2—C—OR
3d
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Reactions of the Double Bond
Diels-Alder Reactions
Hydrogenation
Halogenations Hydrodimerization.
3e
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Reactions of Both Functional Groups
Cyanoethylation Reactions (Michael-Type
Additions)
CH2=CHCN + RH RCH2CH2CN
4a
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USES AND APPLICATION
Acrylic Fibers.
Copolymer Resin ("Plastics'').
Nitrile Rubbers and Resins.
4b
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Shahzad Ali Zahid
(2k11-Che-49)
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MANUFACTURING PROCESSES
Early Processesa.Passage through ethylene cyanohydrin
The following reactions are involved:
CH2-CH2+ HCN CH2OH-CH2-CN
O
CH2OH-CH2-CN CH2=CH-CN+H2O
Temperature 200°C
Yield 90%
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b. Addition of hydrogen cyanide to acetylene
HC CH +HCN CH≡ 2=CH-CN
∆H0298≈ -175 kJ / mol
catalyst consisting of cuprous chloride and
ammonium chloride in solution in hydrochloric acid
temperature of 80 to 90°C
molar yield is up to 90 per cent
by-products are acetaldehyde, vinyl acetylene,divinylacetylene, vinyl chloride, cyano butene, lacto nitrile,
methyl vinyl ketone
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C. Passage through lactonitrile
CH3-CHO + HCN CH3CHOH-CN (10-20) °C
CH3CHOH-CN CH2-CH-CN + H2O
Yield 90 percent
D. Nitric oxide with propylene
4CH2=CH-CH3+6NO 4CH2=CH-CN + 6H2O + N2
E. From Propionitrile.
CH3CH2CN CH2= CHCN + H2
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F. From Propionaldehyde.
CH3CH2CHO + NH3 CH2 = CHCN + H20 + 2H2
G. Acrylonitrile Manufacture by ammoxidation of
propylene (Sohio Process)CH2=CH-CH3+NH3+3/2O2 CH2=CH-CN+3H2O
∆H0298 ≈ -515kJ/mol
Better quality product
Economical Its conversion in a single pass is high
Energy efficient process
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PROCESS DESCRIPTION
Raw Material
Ammonia (NH3) Air
Propylene(C3H6)
FEED RATIO= PROPENE/AMMONIA/AIR=1/1.2/9.5
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the oxygen (air) is introduced below
mixed propylene and ammonia through
“spiders” positioned above the grid
The operating pressure should be low to preventthe by-ptoducts
The residence time in the reactor is between
2 and 20 s
The main reaction isCH2=CH-CH3+NH3+3/2O2 CH2=CH-CN+3H2O
∆H0298 ≈ -515kJ/mol
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It now appears clear that this overall result can
be explained by the production of Acrolein as the
main intermediate
CH2 = CH – CH3 + O2 CH2 = CH – CHO + H2O
CH2 = CH – CHO + NH3 CH2 = CH – CH = NH + H2O
CH2= CH – CH = NH +1 /202 CH2 = CH – CN + H2O
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EFFECT OF DIFFERENT VARIABLES
ON CONVERSATION
Effect of residence time
Effect of reaction temperature
Effect of reaction pressure
Effect of Catalyst
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REACTION MECHANISM
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PROCESS FLOW DIAGRAM
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QUENCHER
It is used to remove ammonia from the reactor
effluent and low down its temperature using sulphuric
acid. It produces ammonium sulphate salt ((NH4)2SO4)
at bottom which is used as a fertilizer and the top
effluent is sent to absorber.
No. of Stages : 10
Sulphuric acid: 30% concentrated H2SO4
Bottom stream coming out of quencher mainly consists
of ammonium sulphate. This stream is further passed
into Crystallizer where crystals of ammonium sulphateare produced which is used as fertilizer.
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ABSORBER
Function of Absorber is to remove the residual gases,
containing unconverted propylene, CO2 and other VOC.
Random Packing: 5 segments of Raschig rings made up of
ceramic, diameter=0.375in
Height of each packing segment=10ft Column Diameter=5ft
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RECOVERY UNIT
Idea is to recover the useful components from the
aqueous solution like ACN, AN etc.
No. of stages: 10
Random Packing: Saddles made up of ceramic,diameter=0.5in
Total tower height=40ft
Column diameter=5ft
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CATALYST
Sohio, who initially employed bismuth phosphomolybdate
in 1967 by a mixture based on oxides of antimony and
uranium
In 1972, Sohio then returned to an iron and bismuth
phosphomolybdate doped by additions of cobalt, nickel andpotassium
The catalysts used in the process are mostly based on
mixed metal oxides such as bismuth-molybdenum oxide,
iron-antimony oxide, uranium-antimony oxide, tellurium
- molybdenum oxide etc.
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Adnan Rafi
2k11-Che-15
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HAZOP STUDY
A HAZOP survey is one of the most common and
widely accepted methods of systematic
qualitative hazard analysis.
It is used for both new or existing facilities and can
be applied to a whole plant, a production unit, or
a piece of equipment
4c
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OBJECTIVES OF A HAZOP STUDY
To identify areas of the design.
To identify and study features of the design.
To familiarize the study team.
To ensure a systematic study.
To identify pertinent design information.
To provide a mechanism for feedback.
4d
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STEPS OF HAZOP STUDY
1. Specify the purpose
2. Select the HAZOP study team
3. Collect data
4e
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5a
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HAZOP GUIDE WORDS AND
MEANINGS
5b
Guide Words Meanings
No Negation of design Intent
Less Quantitative decrease
More Quantitative increase
Part of Qualitative decrease
As well as Qualitative increase
Reverse Logical opposite of
Other than Complete substitution
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4. Conduct the study
5. Write the report
HAZOP Study of Storage Tank for Propylene