Energy Balance
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Transcript of Energy Balance
ENERGY BALANCE
Compressor K-100:
Inlet Conditions: Temperature 303 KOutlet conditions: Pressure 202 Kpa
mass flow rate of air 112020.11 kg/hr1.0748427 kgmol/sec
Inlet volumetric flow rate:
26.73811 m3/secpoly tropic efficiency 76%
Outlet temperature for poly-tropic flow:
then m 0.3759398T2 393.19845 K 120.0485 C
Work per mole for poly-tropic flow
n 1.6024096Work 68.903642 KJ/kgmol
Power Requirement
actual work 90.66269 KJ/kgmolpower requirment 97.44813 KW
Air Pre-heater E-101:
Inlet conditions temperature 120.04845 COutlet conditions temperature 380 Creference temperature 120 Cmoisture in air 107.5 kgmol
heat taken by air 31302131 KJ/hr
Benzene Pre-heater E-100:
Inlet conditions temperature 30 C PressureOutlet conditions temperature 110 C Pressureboiling point of benzene 104.7 Creference temperature 30 C
heat taken by benzene feed from benzene preheater
heat taken by benzene 2393544 KJ/hr
Feed Mixer MIX-100:
reference temperature 110 C
Assuming Tmix 350 Caverage temperature 230 C
component m (kgmole/hr) Cp (KJ/kgmole oC)
Air 3923.21 30.57Benzene 59.02 59.02
128094.5 (Tmix-110) = 32454335Tmix 363.3625 C
Reactor PFR-100:
Chemical Reactions:
C6H6 + 4.5 O2 C4H2O3 + 2CO2 +2H2O(Maleic Anhydride)
C6H6 + 7.5O2 6CO2 +3H2O
C6H6 + 4.5 O2 6C0 + 3H2O
C6H6 + 1.5 O2 C6H4O2 + H2O(quinon)
At steady state Heat input to reactor = Heat output from reactor
component m Cpℓ ΔTℓ
Air 3816Moisture 107.5 72.94 75Benzene 59 133 53
entahlpy of reactants 5.19E+07 KJ/hr
Enthalpy of products leaving at 400C:
component m Cpℓ ΔTℓ
Nitrogen 3014Oxygen 512Water 225 72.94 75CO2 122MAN 43 158 177CO 26Benzene 5 133 53Quinone 0.94 182 155
Enthalpy of products leaving at 400C 60092831
Heat produced by reactions assuming reaction takes place at 25C
By reaction (R1) -8.00E+07By reaction (R2) -1.92E+07
By reaction (R3) -6.56E+06By reaction (R4) -4.23E+05
Total Heat of reaction at 25C ΔHR 1.06E+08Heat taken by cooling salt 9.80E+07
Waste Heat Boiler E-102:
Product steam (8) from the reactor is cooled from 400C to 76.5C at 152Kpa. For energybalance around Waste Heat Boiler assume 76.5C as reference temperature.
average temperature 238.25 C
enthalpy of stream (8)
component m Cpℓ ΔTℓ
Nitrogen 3014Oxygen 512Water 225 73.56 24CO2 122MAN 43 163 126CO 26Benzene 5Quinone 0.94 189.2 104
Heat removed in waste heat boiler
Pre-scrubber cooler E-103:
Stream(11) is cooled from 76.5C to 50C before it enters Gas Scrubber. For energy balanceassuming 50C as reference temperature.
heat removed in pre-scrubber = {ehtahlpy of stream (12)}-{enthalpy of stream (11)}
component m Cpℓ ΔTℓ
Nitrogen 3014Oxygen 512Water 225 72.94 26.5CO2 122MAN 25.35 148 26.5CO 26Benzene 4.71 137 26.5Quinone 0.71 171.2 26.5
heat removed in Pre-Scrubber cooler
Mixer MIX-101:
Pure water stream (16) is added to scrubbed liquid (13) to keep the concentration of MACsolution up to 40%. Assuming water enters at 30C and 101Kpa while scrubbed liquid isentering at 45C.
stream (15) and (17) are leaving at same temperature. So T15 = T17 = T
Energy balance around mixer MIX-101 is
assuming 30oC as reference temperature
Enthalpy of stream (13)
component m Cpℓ ΔTℓ
Water 4426.43 72.8 15MAC 495.81 206.5 15Quinone 0.71 164.3 15
Total Enthalpy 6371183 KJ/hr
Enthalpy of stream (15)
component m Cpℓ ΔTℓ
Water 4551.1 72.8 (T-30)MAC 470.9 206.5 (T-30)
Total Enthalpy 428560.9 (T-30) KJ/hr
Enthalpy of stream (17)
component m Cpℓ ΔTℓ
Water 236.3 72.8 (T-30)MAC 24.89 206.5 (T-30)Quinone 0.71 164.3 (T-30)
Total Enthalpy 22459.08 (T-30) KJ/hr
temperature of stream(15) and (17) T 4.41E+0144.1
Scrubber T-100:
MAN is absorbed in 40% solution of MAC entering at 44.2C while the gases leaves from the topof scubber in vent stream (14).
For energy balance assuming 44.2C as reference temperature.
Reaction involved in scrubber
Reaction taking place:
C4H2O2 + H20 C4H4O4(maleic acid)
∆H 3.60E+04 KJ/kgmol
Enthalpy of stream (12)
component m Cpℓ ΔTℓ
Nitrogen 3014.4 29.33 6.8Oxygen 512 29.51 6.8Water 234 72.78 6.8CO2 122 39.25 6.8MAN 25.35 144.4 6.8CO 26.22 29.91 6.8Benzene 4.71 133.3 6.8Quinone 0.71 167 6.8
Total Enthalpy 887615.5
Enthalpy of stream (13)
component m Cpℓ ΔTℓ
Water 4426.43 72.8 0.8MAC 495.81 206.5 0.8
Quinone 0.71 164.3 0.8
Total Enthalpy 339796.4
Enthalpy of stream (14)
component m Cpg ΔTg
Nitrogen 3014 29.26 (T-44.2)Oxygen 512 29.48 (T-44.2)Water 333.6 72.79 (T-44.2)CO2 122 39.16 (T-44.2)MAN 0.43 144.4 (T-44.2)CO 26 29.22 (T-44.2)Benzene 4.71 131.2 (T-44.2)
Total Enthalpy 133783.4
energy balance provides T14 48.025728 C
Dehydrator feed pre-heater E-104:
Feed is heated from 44.2C to 95C in vapor phase befor it enters the dehydrator
component m Cpℓ ΔTℓ
Water 236.3 73.1 51MAC 24.89 215.8 51Quinone 0.71 173.6 51
heat duty of Dehydrator feed preheater
Dehydrator T-101:
Operating conditions: Top plate temperature = 55C Re-boiler temperature = 120 C Operating pressure = 15.2 kpaAssuming 100C as reference temperature
Reactions involved
(maleic acid) (fumaric acid)
Overhead condenser:
Overhead product is condensed from 55C to 45C at 15.2Kpa. Boiling point of water at 15.2Kpa = 53.6C Boiling point of O-xylene at 15.2Kpa = 85.05CTaking 25oC as reference temperature
Enthalpy of stream (19)
component m Cpℓ
Water 248 72.77O-xylene 72 194.3
Total Enthalpy
Enthalpy of stream (20)
component m Cpℓ
Water 248 72.77O-xylene 72 192.3
Total Enthalpy
heat duty of overhead condenser
heat duty of overhead condenser 10973715
Enthalpy of stream (18) entering at 95C and 101Kpa
component m Cpℓ
Water 236.3 72.9MAC 24.89 212.4Quinone 0.71 170.4
Total Enthalpy
Enthalpy of stream (26) leaving at 120oC and 15.2KPa
component m Cpℓ
Water 13.07 72.77MAN 24.77 149.7O-xylene 3.79 200.4Fumaric acid 0.12 251Quinone 0.71 173.8
Total Enthalpy
Enthalpy of reflux stream (21) 291488.34
Heat required by reaction (R1) 8.92E+05
Heat required by reaction (R2) 4.68E+02
Total heat required for reactions 8.92E+05
heat duty of Re-boiler
heat duty of Re-boiler
Mixer MIX-102
Stream (27) entering at 120oC and 101Kpa is mixed with crude MAN stream (10).
Assuming 25oC as reference temperature so Enthalpy of stream (27)
component m
Water 13.07MAN 24.77O-Xylene 3.79Fumaric Acid 0.12Quinone 0.71
Enthalpy of stream (28)
component m
Water 14.75MAN 42.51O-Xylene 3.79Fumaric Acid 0.12Quinone 0.94
Total Enthalpy
Enthalpy of stream (10)
component m
water 17.74MAN 1.68quinon 0.23
enthalpy balance around mixer is1185553.4 =
514664.4
Distillation Coulmn T-102
Operating conditions:
Assuming 25C as reference temperature
Enthalpy of feed stream (29) entering at 108C
component m
Water 14.75MAN 42.51O-Xylene 3.79Fumaric Acid 0.12Quinone 0.94
Enthalpy of stream (30)
component m
Water 54.15MAN 1.03O-Xylene 13.27Quinone 3.06
Enthalpy of stream (31)
component m
Water 36.9MAN 0.73
O-Xylene 9.5Quinone 2.2
Enthalpy of stream (32)
component m
Water 14.75MAN 0.29O-Xylene 3.79Quinone 0.87
Enthalpy of stream (36)
component m
MAN 42.21Fumaric Acid 0.12Quinone 0.17
Heat duty of condenser
Heat duty of condenser
Heat duty of re-boiler
ENERGY BALANCE
Pressure 101 Kpa
4
21.2976847
0.3759398 1.297685 0.297685 231.4652R 0.0821 m3atm/kgmolK
8.314 KJ/kgmolKZi 1
Pressure 202 KpaPressure 202 Kpa
202 Kpa202 Kpa
m Cp
119932.58168.37
(R1) ∆H -1.86E+06 KJ/kgmol
(R2) ∆H -3.26E+06 KJ/kgmol
(R3) ∆H -1.50E+06 KJ/kgmol
(R4) ∆H -4.50E+05 KJ/kgmol
CpℓΔTℓ Cpg ΔTg λ
32.21 338 10886.985470.5 35.65 263 9375.95 4.00E+04
7049 136.4 285 38874 2.90E+04
CpℓΔTℓ Cpg ΔTg λ
30.16 375 1131030.94 375 11602.5
5470.5 35.83 300 10749 4.00E+0443.87 375 16451.25
27966 162.5 198 32175 4.70E+0429.81 375 11178.75
7049 140.4 322 45208.8 2.90E+0428210 172.6 220 37972 4.40E+04
KJ/hr
KJ/hrKJ/hr
Cpg∆Tg
Cpg∆Tg
KJ/hrKJ/hrKJ/hrKJ/hr
Product steam (8) from the reactor is cooled from 400C to 76.5C at 152Kpa. For energy
CpℓΔTℓ Cpg ΔTg λ
30.27 324 9807.4831.18 324 10102.32
1765.44 35.77 300 10731 4.10E+0444.47 324 14408.28
20538 162.2 198 32115.6 4.80E+0429.93 324 9697.32140.2 322 45144.4 3.00E+04
19676.8 172.3 220 37906 4.50E+04
53579027 KJ/hr
Cpg∆Tg
Stream(11) is cooled from 76.5C to 50C before it enters Gas Scrubber. For energy balance
CpℓΔTℓ Cpg ΔTg λ
29.4 26.5 779.129.6 26.5 784.4
1932.9139.72 26.5 1052.58
392229.22 26.5 774.33
3630.54536.8
3453016 KJ/hr
Pure water stream (16) is added to scrubbed liquid (13) to keep the concentration of MAC
Cpg∆Tg
CpℓΔTℓ ∆H
1092 48336623097.5 15357712464.5 1749.795
∆H
331320.1 (T-30)97240.85 (T-30)
∆H
17202.64 (T-30)5139.785 (T-30)
116.653 (T-30)
CC
MAN is absorbed in 40% solution of MAC entering at 44.2C while the gases leaves from the top
(maleic acid)
CpℓΔTℓ ∆H
199.444 601204200.668 102742494.904 115807.5
266.9 32561.8981.92 24891.67
203.388 5332.833906.44 4269.3321135.6 806.276
KJ/hr
CpℓΔTℓ ∆H
58.24 257795.3165.2 81907.81
131.44 93.3224
KJ/hr
∆H
88189.64 (T-44.2)15093.76 (T-44.2)24282.74 (T-44.2)
4777.52 (T-44.2)62.092 (T-44.2)759.72 (T-44.2)
617.952 (T-44.2)
(T-44.2) KJ/hr
CpℓΔTℓ ∆H
3728.1 88095011005.8 273934.4
8853.6 6286.056
1161170 KJ/hr
∆H 3.60E+04 KJ/kgmol
∆H 3.90E+03 KJ/kgmol
Boiling point of water at 15.2Kpa = 53.6C Boiling point of O-xylene at 15.2Kpa = 85.05C
ΔTℓ CpℓΔTℓ Cpg ΔTg
28.6 2081.222 33.8 1.4 47.3230 5829
11611566 KJ/hr
ΔTℓ CpℓΔTℓ ∆H
20 1455.4 360939.220 3846 276912
637851.2 KJ/hr
KJ/hr
ΔTℓ CpℓΔTℓ ∆H
70 5103 120583970 14868 370064.570 11928 8468.88
1584372 KJ/hr
ΔTℓ CpℓΔTℓ Cpg ΔTg
28.6 2081.222 34.03 66.4 2259.59295 14221.560 12024 163.1 35 5708.595 2384595 16511
Cpg∆Tg
Cpg∆Tg
1208191 KJ/hr
1.18E+07 KJ/hr
Stream (27) entering at 120oC and 101Kpa is mixed with crude MAN stream (10).
Assuming 25oC as reference temperature so Enthalpy of stream (27)
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
72.77 75 5457.75 34.42 20149.7 95 14221.5
207 95 19665251 95 23845
173.8 95 16511
Total Enthalpy 1044511 KJ/hr
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
73.12 75 5484 34.4 (T-100)149.7 (T-25)
207 (T-25)251 (T-25)
173.8 (T-25)
Total Enthalpy 670889 + 507.4 (T-100) + 7341.769 (T-25)
Cpℓ ΔTℓ CpℓΔTℓ ∆H
145.3 51.5 7482.95 132747.572.8 51.5 3749.2 6298.656
168.5 51.5 8677.75 1995.883
Total Enthalpy 141042.1 KJ/hr
670889 + 507.4 (T-100) + 7341.769 (T-25)
= -234284 + 7849.169 T
T = 95.417565 C
Top plate temperature = 160C
Re-boiler temperature = 200 C
Reflux temperature = 112C
Operating pressure = 101 kpa
Enthalpy of feed stream (29) entering at 108C
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
73.12 75 5484 34.38 8148.4 83 12317.2204.9 83 17006.7250.2 83 20766.6
172 83 14276
Total enthalpy 1278917 KJ/hr
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
73.12 75 5484 34.57 60153.6 135 20736212.3 119 25263.7 181.8 16179.1 135
Total enthalpy 3461474 KJ/hr
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
73.12 75 5484 34.38 12148.4 87 12910.8
204.9 87 17826.3172 87
Total enthalpy 1872358 KJ/hr
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
73.12 75 5484 34.38 12148.4 87 12910.8204.9 87 17826.3
172 87 14964
Total enthalpy 761298.7 KJ/hr
Cpℓ ΔTℓ CpℓΔTℓ Cpg ΔTg
157.8 175 27615256.6 175 44905181.9 155 28194.5 152.2 20
Total enthalpy 1184148 KJ/hr
Heat duty of condenser 827817.14 KJ/hr
Heat duty of re-boiler 1494347 KJ/hr
∆H
415447165.90E+064420457
∆H
340883405940480
1264938820070534607063
290647.5406289
103571.1
∆H
295597455172388
1203669917578104328105
252130.3375722
96427.83
∆H
2348207401612.8434904.7128414.8
99422.720132.5817099.663221.128
λ ∆H
4.30E+04 11191878419688
λ ∆H
4.30E+04 618744.4352266.6
4.10E+04 222596.22861.4
11722.81
λ ∆H
688.4 4.00E+04 603130.2352266.674530.35
2861.411722.81
Cpg∆Tg
λ ∆H
34.4 (T-100) 4.00E+04 670889 + 507.4 (T-100)6363.747 (T-25)
784.53 (T-25)30.12 (T-25)
163.372 (T-25)
Cpg∆Tg
λ ∆H
275.04 40000 674945.8523604.264455.392491.99213419.44
λ ∆H
2074.2 40000 257527721358.08
2908.8 37000 864839.1
λ ∆H
412.56 40000 16935839424.884
Cpg∆Tg
Cpg∆Tg
Cpg∆Tg
169349.9
λ ∆H
412.56 40000 676974.33744.13267561.6813018.68
λ ∆H
11656295388.6
3044 46000 13130.55
Cpg∆Tg
Cpg∆Tg