The document describes the production of acrylonitrile via the ammoxidation of propylene. It involves three main steps: 1) The ammoxidation reaction of propylene, ammonia, and oxygen over a bismuth phosphomolybdate catalyst to produce acrylonitrile, water, and other byproducts. 2) Further processing of the reaction products using various separation techniques like distillation columns and absorbers to purify the acrylonitrile. 3) Material and energy balance calculations to determine the inputs, outputs, heat of reactions, and energy requirements of the process. A fluidized bed reactor design is also proposed for the ammoxidation reaction.

1. Production of Acrylonitrile by
Ammoxidation of Propylene
Aditya Kotecha(16CH022)
Ashish Pal(16CH039)
Guide :Dr. K R Jethani
All India Shri Shivaji Memorial Society’s
College of Engineering-Pune
1

2. Introduction
• It was first prepared in 1893 by the french
chemist Charles
• Chemical formula:C3H3N
• it consists of a vinyl group linked to a nitrile
• This is pungent-smelling colorless liquid
• It is monomer for the manufacturing of plastic
• It produces toxic combustion product
2

3. Properties
• Substance name: Acrylonitrile
• Molecular wt.: 53.064
• Boiling point: 77.3°C
• Freezing point: 83.5°C
• Density: 0.806 g/cm3
• Vapor density: 1.8
• Critical Temperatures:246°C
• Critical Pressure: 3.54Mpa
• pH (5% aqueous solution): 6.0 -7.5
3

4. Types of Production Of Acryolnitrile
• Ammoxidation of propylene
• Ethylene Cyanohydrin route
• Acetylene- Hydrogen Cyanide
4

5. Ammoxidation of propylene
(Sohio Process)
5

6. • Heat from exothermic main, side and secondary
reactions evolved, via fluidized bed and heat
exchanger utilize in steam generation.
• Reaction
H2C=CHCH3 +NH3+ 1.5 O2 H2C=CHCN+ 3H2O
[Catalyst = bismuth phosphomolybate]
6

7. Ethylene Cyanohydrin route
7

8. • Two-step homogeneously catalyzed reaction to
intermediate Cyanohydrin with subsequent
homogeneously or heterogeneously Catalyzed
dehydration.
• Reactions
C2H4O + HCN CH2(OH)CH2CN
[Al2O3 Cat.]
CH2(OH)CH2CN H2C = CHCN + H2O
[Al2O3 Cat.]
8

9. Acetylene- Hydrogen Cyonide
9

10. • Single-step, homogeneously Catalyzed
hydrocyanation in the liquid phase
• Reaction
HC=CH + HCN H2C = CHCN
[Cu2Cl2 Cat.]
10

11. 11

12. MATERIAL BALANCE
12

13. Basis: moles of Propylene = 30004.626 Kg/hr
Plant Capacity= 300000 tones/year
Plant Capacity = 37.87879 tones/hr
Yield of product =80%
Compound Molecular Weight
ACN 53.06
HCN 27.01
AcetoNitrile 41.02
Propylene 42.03
Ammonia 17
Oxygen 32
H2O 18
Propane 44
Poly ACN 1250
13

14. Reactor
Reactor
NH3
O2
C3H6
Product
1) H2C=CHCH3 +NH3+ 1.5 O2 H2C=CHCN+ 3H2O (Acrylonitrile)
2) C3H6 + 3NH3 + 3O2 3HCN +6H2O (HCN)
3) C3H6 + 1.5O2 + 1.5 NH3 1.5CH3CN + 3H20 ( Acetonitrile) 14

15. Feasibility of the reaction
• Reaction
C3H6+NH3+3/2 O2 C3H3N+3H20
Reactants
15
Group ni niΔG
NH3 1 -16.160
CH2= 1 3.77
=CH- 1 48.53
-CH3 1 -43.96
O2 3/2 0
TOTAL -7.82

16. • Products
16
Group ni niΔG(KJ/mol)
CH2= 1 3.77
=CH- 1 48.53
-CN 1 89.22
H2O 3 -288
TOTAL -146.48
ΔG= Σ(ΔG)p – Σ(ΔG)r
= (-146.48) – (-7.82)
= -138.66 KJ/mol
Therefore, Reaction is feasible/Spontaneous

17. Sr. No. Name of compound Input(Kg/hr) Output(kg/hr)
1 Propylene 30004.626
2 NH3 13349.667 1577.688
3 O2 36550.96 5254.201
4 ACN 30303.03
5 HCN 1542.565
6 Acetonitrile 2635.524
7 H2O 35208.85
8 N2(inert) 122366.3 122366.3
9 Propane(inert) 31410.98 31410.98
10 Poly. ACN 3383.82
Total 233682.534 233682.534
17
Reactor

18. Quench
Quench
Column
Top Products
H2SO4(aq.)
H2O(From aceto
column)
Aqueous (NH4)2SO4 and
impurities (bottom Product)
Feed
18

19. Sr.
No.
Name of
compound
Feed(Kg/hr) Output(Kg/hr)
Top Product Bottom Product
1 ACN 30303.03 30303.03 -
2 HCN 1542.565 1542.565 -
3 Acetonitrile 2635.524 2635.524 -
4 NH3 1577.688 - -
5 Oxygen 5254.201 5254.201 -
6 H2O 70417.7 35208.85 35208.85
7 N2(inert) 122366.3 122366.3 -
8 Propane(inert) 31410.98 31410.98 -
9 Poly. ACN 3383.82 2255.99 1127.83
10 H2SO4 4547.453 - -
11 (NH4)2SO4 - - 6131.638
TOTAL 273439.261 230977.4 42468.318
273439.261
19

20. Absorber
Absorber
Feed
Off-Gases
Product
20
H20

21. Sr. No. Name of compound Feed(Kg/hr) Product(Kg/hr)
Off-gases product
1
ACN 30303.03 30303.03
2
HCN 1542.565 77.12824 1465.436
3
Acetonitrile 2635.524 2635.524
4
O2 5254.201 5254.201
5
N2 122366.3 122366.3
6
Propane 31410.98 31410.98
7
Poly. ACN 2255.99 2255.99
8
H2O 35208.85
35208.85
Total 230977.44 159108.609 71868.83
230977.44
21

22. Product Splitter
To HCN and ACN
Column
Feed
To Acetonitrile
column
Product
Splitter
22

23. Sr.
No.
Name of compound Feed(Kg/hr) Product(Kg/hr)
Top product Bottom Product
1
ACN 30303.03 30000 303.0303
2
HCN 1465.436 1450.782 14.65436
3
Acetonitrile 2635.524 26.35524 2609.169
4
Poly. ACN 2255.99 1128 1128
Total 36659.98 32605.137 4054.85336
36659.98
23

24. HCN Column
Azetropic
column
Feed
Top Product
Bottom Product
24

25. Sr. No. Name of compound Feed(Kg/hr) Product(Kg/hr)
Top Product Bottom Product
1
ACN 30000 300 29700
2
HCN 1450.782 1443.528 7.253911
3
Acetonitrile 26.35524 26.35524
4
Poly. ACN 8924.02 8924.02
Total 40401.15724 1743.528 38657.62915
40401.15715
25

26. Aceto column
Azetropic
column-ii
Feed
(from product
splitter)
Top Product
Heavy Ends
26

27. Sr. No. Name of compound Feed(Kg/hr) Product(Kg/hr)
Top Product Heavy Ends
1
ACN 303.0303 3.030303 300
2
HCN 14.65436 7.327182 7.327182
3
Acetonitrile 2609.169 2556.985 52.18338
4
Poly. ACN 1128 1128
Total 4054.85 2567.34 1487.51
Total 4054.85
27

28. ACN Column
ACN
Column
Feed
(from HCN
column)
ACN
Heavy ends
28

29. Sr. No. Name of compound Feed(Kg/hr) Product(Kg/hr)
Top Product Heavy Ends
1
ACN 29700 29403 297
2
HCN 7.253911 7.253911
3
Acetonitrile 26.35524 10.5421 15.81314
4
Poly. ACN 1128 1128
Total 30861.609 29420.796 1440.813
30861.609
29

30. Energy Balance
30

31. Energy –Energy + Energy + Energy = Energy
In Out Generated Consumed Accumulated
Reactions
1)ACN
C3H6+NH3+3/2 O2 C3H3N+3H20
2)HCN
C3H6+3NH3+3O2 3HCN+6H2O
3) AcetoN
C3H6+1.5NH3+1.5O2 1.5CH3CN+3H2O
Cp=A+BT+CT2+DT3+ET4 (J/mol K)
31

32. Sr.
No.
Name of
compound
A B C D E Cp(J/mol
K)at723K
1 Propeylene 31.298 0.07244 0.0001948 -2.1582E-07 6.2974E-11 121.1415836
2 Ammonia 33.573 -0.012581 0.000088906 -7.1783E-08 1.8569E-11 48.89540981
3 Oxygen 29.526 -0.00889990.000038083 -3.2629E-08 8.8607E-12 33.08803012
4 Acetonitrile 36.947 0.022085 0.00014334 -1.502E-07 4.3482E-11 82.9581487
5 Acrylonitrile 18.425 0.18336 -0.00010072 1.8747E-08 9.1114E-13 105.6790913
6 HCN 25.766 0.037969
-
0.000012416 -3.224E-09 2.261E-12 46.12673585
7 Water 33.933 -0.00841860.000029906 -1.7825E-08 3.6934E-12 37.75163408
8 Nitrogen 29.342 -0.00353950.000010076 -4.3116E-09 2.5935E-13 30.49132894
9 Propane 28.277 0.116 0.00019597 -2.3271E-07 6.8669E-11 145.3989007
10 H2SO4 9.466 0.33795 -0.0003807 2.1308E-07 -4.6878E-11122.52169
Gases
32

33. Reactor
Component Heat Input (J/hr) Heat Output (J/hr)
Feed Stream 73202094.07 -
Output Stream - 173709556248
Heat of reaction (Exothermic
reaction)
- -101108122182
Heat added (Molten salt solution) 0 0
Total 73202094.07 73202094.07
Reactor
Reaction
temp=
723 K
33

34. Gas Cooler
Component Heat Input (J/hr) Heat Output (J/hr)
Feed Stream 173709556248 -
Output Stream - 75911307691
Heat of reaction - -
Heat removed by water 97798248557 -
Total 75911307691 75911307691
Gas
Cooler
T= 723 K T=503 K
34

35. Quench Column
Component Heat Input (J/hr) Heat Output (J/hr)
Feed Stream 76493783455 -
Output Stream - 73327924815
Heat of reaction (Exothermic
reaction)
- 99389031382
Heat added for quenching 121127763400
Heat removed by water 51589192816 -
Total 172716956200 172716956200
Quench
Column
T=503 K
T= 358 K
Top product
H2O in
H2SO4 in
Ammonium Sulphate
35

36. Absorber
Component Heat Input (J/hr) Heat Output (J/hr)
Feed Stream 99389031382 -
Output (off gases) - 7491270847
Output (bottom product) - 2974549067
Heat removed by water 0 0
Total 99389031382 99389031382
Absorber
Column
Feed
T= 385 K
Off gases
Product
T=313 K
36

37. Product Splitter
37
Component Heat Input (KJ/Day) Heat Output (KJ/Day)
Feed stream 6119900245 -
Distillate - 1188294817
Bottoms - 369955315.6
Heat load of condensor - 44318569073
Heat load of reboiler 40006930970 -
Total 4.6*1010 4.6*1010
350 K
350 K
358 K

38. HCN Column
38
38
329 K
350 K
329 K
Component Heat Input (KJ/Day) Heat Output (KJ/Day)
Feed stream 244815032.5
Distillate - 59434085.75
Bottoms - 3105588628
Heat load of condensor - 3603604975
Heat load of reboiler 6523812657 -
Total 6768627690 6768627689

39. Aceto column
39
39
39
355 K
355 K
Component Heat Input (KJ/Day) Heat Output (KJ/Day)
Feed stream 369955315.6
Distillate - 288087119.3
Bottoms - 76252620.67
Heat load of condensor - 4100160981
Heat load of reboiler 4094545406 -
Total 4464500722 4464500722
350 K

40. ACN Column
40
Heavy Ends
Feed
ACN
Component Heat Input (KJ/Day) Heat Output (KJ/Day)
Feed stream 3105588628
Distillate - 3034235835
Bottoms - 71352793.09
Heat load of condensor - 39776260460
Heat load of reboiler 39778114321 -
Total 4.28*10^10 4.28*10^10

41. Reactor Design
• A fluidized bed reactor is a type
of reactor device that can be
used to carry out a variety of
multiphase chemical reactions.
In this type of reactor, a fluid is
passed through a solid granular
material at high enough
velocities to suspend the solid
and cause it to behave as
though it were a fluid.
41

42. Procedure
Catalyst bed data:
 Catalyst: C-49 (Ferobysmuth-molybdate)
 Density: 1500 kg/m3
 Avg diameter of catalyst: 50um
 Shape factor: 0.7
 Average density: PM/RT=0.86kg/m3
 G=233682.534 kg/hr=64.91 kg/sec
 Weight of catalyst(using WHSV):324.55 Kg
42

43. Procedure
• Assuming L/D=3
• Crossectional area= π/4D2
• Surface area of reactor= πDL=3 πD2
• Using Leva’s Equation:
Gmf: 0.150 Kg/m2s
Gmf(actual)= 15*Gmf=2.25 Kg/m2s
G(actual)=mass flow rate/C.S.A of reactor
• C.S.A of reactor= 28.8 m2
43

44. Procedure
• π/4D2=28.8
• D=6.05m, L=3D=18.17
• Top diameter of fluidized reactor=
1.2*D=7.26m
44

45. Mechanical Design
• Thickness of reactor
J=0.85
t= pDo/(2fJ+p)
= 2.82 mm
Taking corrosion allowance = 3 mm
Taking standard value = t= 6 mm
• Tower Height for various external and internal loads
Height of reactor= 20.17 m
MOC : Carbon Steel
Specific Gravity = 7.7
1)Axial stress Due to Pressure
Fap=413.41 Kgf/cm2
45

46. 2) Stress Due to Dead loads
a) Compressive stress due to weight of shell up
to distance ‘x’
fds= ρs(x)=7.7*10-3(x) kgf/cm2
b) Compressive stress due to weight of
insulation upto distance ‘x’
fdins= (tinsρinsx)/(ts-c)
=0.0564(x) kgf/cm2
46

47. C) Compressive stress due to attachments
Weight of standard dished head
=π/4(D-1.2)2*t*ρs
= 1928.45 kg
Fdatt=324.55+1928.45/(D(ts-c)= 3.52 Kgf/cm2
Total compressive stresses,
Fds=fds+fdins+fdatt=0.0641(x)+3.52
47

48. Conclusion
• We have Studied literatue survey for the given
process
• We have selected SOHIO process based on
various parameters.
• We have tested thermodynamic feasibility for
the given process which is spontaneous.
• We have done mass balance and energy
balance for the Sohio process.
48

49. Thank you
49