Equipment wise Material and Energy Balance for Cumene Production from Benzene and Propylene

Approximate calculation of material balance for Cumene production process from Benzene and Propylene based on the Flowsheet: used for production of 300 tons/day of cumene.

Equipment

Benzene feed pump
Propylene feed pump
Benzene column
Benzene feed


Benzene fresh feed
Propylene -propane
Recycle benzene
Benzene mixed feed

Mw
kmole
kg
kmole
kg
kmole
kg
kmole
kg
BENZENE
78
107.52
8387.09


114.24
8911.28
221.77
17298.4
PROPYLENE
42


112.00
4704.29

0


PROPANE
44


5.89
259.38

0


CUMENE
120




2.21
266.08
2.21
266.088
DIPB
162





0


TOTAL


8387.09

4963.68

9177.37

17564.5











Equipment

Reactor
Reactor
Flash drum top
Flash drum bottom


Reactor input
Reactor out put
Fuel gas
Feed to benzene column

Mw
kmole
kg
kmole
kg
kmole
kg
kmole
kg
BENZENE
78
221.77
17298.38
114.24
8911.28


114.24
8911.28
PROPYLENE
42
112.00
4704.298
1.119
47.038
1.119
47.03

0
PROPANE
44
5.89
259.38
5.89
259.38
5.89
259.38

0
CUMENE
120
2.212
265.52
106.379
12765.5


106.37
12765.52
DIPB
162
0
0
3.360
544.35


3.360
544.35
TOTAL


22527.59

22527.5

306.42
223.98
22221.17












Equipment

Benzene column top
Benzene column top
Cumene column top
Cumene column bottom


Distilled benzene
Feed to Cumene column
Cumene product
DIPB by-product

Mw
kmole
kg
kmole
kg
kmole
kg
kmole
kg
BENZENE
78
114.2473
8911.289






PROPYLENE
42

0






PROPANE
44

0






CUMENE
120
2.21274
265.5288
104.1667
12500.00
104.16667
12500


DIPB
162

0
3.360215
544.35483
0.10426
16.89012
3.255955
527.465
TOTAL


9176.818

13044.35487

12516.89

527.465

Equipment wise energy balance for 300 Ton/Day Cumene production pilot plant*


Benzene feed vaporizer:
 (*refer above process flowsheet)



Stream of mixed feed of benzene and cumene is feed to vaporizer with 40 oC at 25 atm.

Component
Mol wt
kmole
Kg
mole fraction
mass fraction
BENZENE
78
221.7742
17298.39
0.990101
0.984851
CUMENE
120
2.2174
266.088
0.009899
0.015149
TOTAL

223.9916
17564.48
1
1
 
The bubble point and dew point of mixture are found by using Antoine equation, vapor pressure is calculated at various temperatures to find saturated temperature 

pi
xi
P
yi= pi xi /P
yi P
yi P/ pi
BENZENE
2587.637
0.99
2533.125
1.011305
2507.794
0.969144
CUMENE
660.4975
0.01
2533.125
0.002607
25.33125
0.038352



1.013912

1.007496
 
Where, P is total pressure
Pi is vapor pressure at 243 oC. So, at 516 k the mixed feed will be vaporized. 
Heat required for vaporize =313 int 516(C dT) + latent heat
Latent heat of benzene = 23,773.63 kJ/kmole
Latent heat of cumene = 30919.2 kJ/kmole
Average heat capacity of benzene = 161.46 kJ/kmole k
Average heat capacity of cumene = 246.92 kJ/kmole k

Enthalpy of benzene = Cp ∆T + λ = 161.46 X 203 + 23,773.63 = 56,550.01 kJ/Kmole
Enthalpy of cumene = 246.92 X 203+ 30919.2 = 81043.96 kJ/Kmole
Heat required for the mixed feed = 0.99 X 56550.01+0.1 X 81043.96
= 64088.89 kJ/Kmole
=64088.89 X 223.9= 14349502 kJ = 14349.502 MJ/h
 
Propylene feed vaporizer:                           
Propylene and propane fed from tank with 25 oC at 25 atm.
The stream is vaporized and heat to the temperature 243oC and mixed with benzene feed.
Bubbling point and dew point of mixture is about 62.5 oC
Latent heat of propylene = 17229.4 kJ / h
Latent heat of propane = 17611.41 kJ / h
Average heat capacity of liquid propylene =123.51
 and propane=125.48
 Average heat of capacity of gaseous propylene = 82.86
and propane=97.48
Liquid state:

propylene
propane
Cp
123.51
125.48
∆T
37.5
37.5
Q (kJ/h)
4631.625
4705.5

Gas state :

propylene
propane
Cp
82.86
97.483
∆T
180.5
180.5
Q (kJ/h)
14956.23
17595.6815
 
Heat required for propylene:
17229.46+4631.625+14956.23 = 21861.08 kJ/h
Heat required for propane:
17611.39+4705.5+17595.075 = 39912.57 kJ/h
Heat required for the feed = 117.9 (21861.08 X 0.95 + 39912.57 X 0.05)
= 2683.83 MJ/h
Fired heater:
 Heat required for rise the temperature reactant feed to 350 oC
 







inlet oC
=                243
outlet  oC
=         350

comp
kmole/h
heat capacity constants of gas mixture



n
A
B
C
D
E
C3H6
112.0071
31.298
7.24E-02
1.95E-04
-2.16E-07
6.30E-11
C3H8
5.8951
28.277
1.16E-01
1.96E-04
-2.33E-07
6.87E-11
C6H6
221.7742
-31.368
4.75E-01
-3.11E-04
8.52E-08
-5.05E-12
C9H12
2.21274
10.149
5.11E-01
-1.77E-05
-2.26E-07
8.80E-11
















nA
nB
nC
nD
nE


3.51E+03
8.11E+00
2.18E-02
-2.42E-05
7.05E-09


1.67E+02
6.84E-01
1.16E-03
-1.37E-06
4.05E-10


-6.96E+03
1.05E+02
-6.91E-02
1.89E-05
-1.12E-09


2.25E+01
1.13E+00
-3.92E-05
-5.00E-07
1.95E-10

 Cp=
-3.26E+03
1.15E+02
-4.61E-02
-7.14E-06
6.53E-09















∆ T =
107
31725.5
9508697.667
2879866400
8.8098E+11








 Cp∆ T=
-349019.239
3.65E+06
-4.39E+05
-2.06E+04
5.76E+03















∑ Cp∆ T=
2.85E+06
kJ/h