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:


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)


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)}


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)


Water 4426.43 72.8 15MAC 495.81 206.5 15Quinone 0.71 164.3 15

Total Enthalpy 6371183 KJ/hr



Water 4551.1 72.8 (T-30)MAC 470.9 206.5 (T-30)

Total Enthalpy 428560.9 (T-30) KJ/hr



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



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



Water 4426.43 72.8 0.8MAC 495.81 206.5 0.8

Quinone 0.71 164.3 0.8



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)


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


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


component m Cpℓ

Water 248 72.77O-xylene 72 194.3

Total Enthalpy


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


component m


Total Enthalpy


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



component m

Water 54.15MAN 1.03O-Xylene 13.27Quinone 3.06


component m

Water 36.9MAN 0.73

O-Xylene 9.5Quinone 2.2


component m

Water 14.75MAN 0.29O-Xylene 3.79Quinone 0.87


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


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


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


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



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


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


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


73.12 75 5484 34.57 60153.6 135 20736212.3 119 25263.7 181.8 16179.1 135



73.12 75 5484 34.38 12148.4 87 12910.8

204.9 87 17826.3172 87



73.12 75 5484 34.38 12148.4 87 12910.8204.9 87 17826.3

172 87 14964

Total enthalpy 761298.7 KJ/hr


157.8 175 27615256.6 175 44905181.9 155 28194.5 152.2 20


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

Energy Balance

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