The latest way for the production of acrylonitrile from the ammoxidation of propylene

1. PRODUCTION OF
ACRYLONITRILE BY
AMMOXIDATION OF
PROPYLENE

2. GROUP MEMBERS
 Waheed Ahmed
(2k11-ChE-09)
 Adnan Rafi
(2k11-ChE-16)
 Ahmed Haroon
(2k11-ChE-23)
 Shahzad Ali Zahid
(2k11-ChE-49)
1a

3. CONTENTS
Introduction
Process Description
Site Selection
Hazop study and EIA
1b

4. Introduction
Waheed Ahmad
(2k11-Che-09)
2a

5. INTRODUCTION
 It was first prepared in 1893 by the French
chemist Charles
 Chemical Formula C3H3N.
 This pungent-smelling colorless liquid
 It is monomer for the manufacture of plastics.
 It produce toxic combustion products
2b

6. PHYSICAL PROPERTIES
 colorless liquid and faint characteristic odor.
 Other trade names.
 Acrylonitrile polymerizes explosively.
3b

7. 3c
Property Value
Molecular weight 53.06
Boiling point, 0
C 77.3 At 103.3 kPa
Critical temperature,
0
C
246.0
Density, g/L 806.0 At 20"C
Explosive limit at 250
C, vol
%
3.05-17.0
Flash point 0
C -5
Freezing point, 0
C -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

8. CHEMICAL PROPERTIES
 Reactions of the Nitrile Group
 Hydration and Hydrolysis
 Alcoholysis
NH-HX
CH2=CHCN + ROH + HX XCH2CH2—C—OR
3d

9.  Reactions of the Double Bond
 Diels-Alder Reactions
 Hydrogenation
 Halogenations
 Hydrodimerization.
3e

10.  Reactions of Both Functional Groups
 Cyanoethylation Reactions (Michael-Type
Additions)
CH2=CHCN + RH RCH2CH2CN
4a

11. USES AND APPLICATION
 Acrylic Fibers.
 Copolymer Resin ("Plastics'').
 Nitrile Rubbers and Resins.
4b

12. Shahzad ali zahid
(2k11-Che-49)

13. MANUFACTURING PROCESSES
Early Processes
a. 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%

14. b. Addition of hydrogen cyanide to acetylene
HC ≡ CH +HCN CH2=CH-CN
ΔH0
298 ≈ -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,divinyl
acetylene, vinyl chloride, cyano butene, lacto nitrile,
methyl vinyl ketone

15. 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

16. 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
ΔH0
298 ≈ -515kJ/mol
 Better quality product
 Economical
 Its conversion in a single pass is high
 Energy efficient process

17. PROCESS DESCRIPTION
Raw Material
 Ammonia (NH3)
 Air
 Propylene(C3H6)
FEED RATIO= PROPENE/AMMONIA/AIR=1/1.2/9.5

18.  the oxygen (air) is introduced below
 mixed propylene and ammonia through
“spiders” positioned above the grid
 The operating pressure should be low to prevent
the by-ptoducts
 The residence time in the reactor is between
2 and 20 s
 The main reaction is
CH2=CH-CH3+NH3+3/2O2 CH2=CH-CN+3H2O
ΔH0
298 ≈ -515kJ/mol

19.  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

20. EFFECT OF DIFFERENT VARIABLES
ON CONVERSATION
 Effect of residence time
 Effect of reaction temperature
 Effect of reaction pressure
 Effect of Catalyst

21. REACTION MECHANISM

22. PROCESS FLOW DIAGRAM

23. 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 sulphate
are produced which is used as fertilizer.

24. 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

25. 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

26. 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 and
potassium
 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.

27. Adnan Rafi
2k11-Che-15

28. 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

29. 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

30. STEPS OF HAZOP STUDY
1. Specify the purpose
2. Select the HAZOP study team
3. Collect data
4e

31. 5a

32. 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

33. 4. Conduct the study
5. Write the report
HAZOP Study of Storage Tank for Propylene