This is my 2nd project review. Contains material and energy balances of distillation column

1. JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY KAKINADA
UNIVERSITY COLLEGE OF ENGINEERING KAKINADA(A)
Department of Petroleum Engineering and Petrochemical Engineering
Second project review on
design and simulation of Divided wall column for the separation of reformate
By
T. HARI KIRAN
(15021A2529)
Under the guidance of
Prof. K. V. RAO
Programme Director
Petroleum courses

2.  CONTENTS
Material Balance
Energy Balance
Future work
References

3.  Material Balance
• Plant Capacity
The capacity of the plant = 1 MMTPA
=(1*106*103)/(330*24)
=126262.2 Kg/hr
• Process Specifications
The following are the process parameters used to obtain a purity of 99% Benzene, 98% Toluene & 97% P-Xylene
• Feed Conditions
Temperature: 1350C
Pressure: 150 KPa
Reflux Ratio (R) : 23
Component Composition in feed
Benzene 0.1096
Toluene 0.4217
P-Xylene 0.4687

4.  Flow Diagram
a) Divided wall Column; (b) Thermally coupled distillation

5.  Material Balance
• Average molecular weight of mixture = Σ MiXi
= (0.1096*78.11) + (0.4217*92.14) + (0.4687*106.168)
= 97.17723 Kg/Kmol
• Feed rate = 126,262.2 Kg/hr = 1300 Kmol/hr
97.17723 Kg/Kmol
• Basis: 1300 Kmol/hr of feed enters into the column
• Assumptions
The distillate contains no P-Xylene (HK) in distillate and the bottom products contain no Benzene (LK) component.
• Material Balance Equations for a DWC
Overall Material Balance
F = D + S + W
Where, F = Feed rate, Kmol/hr
S= Side stream rate, Kmol/hr
W= Bottom flow rate, Kmol/hr

6.  Component Balance
• For the component A:
FZA = D2xA,D2 + SxA,S + W3xA,W3
• For the component B:
FZB = D2xB,D2 + SxB,S + W3xB,W3
• For the component C:
FZC = D2xC,D2 + SxC,S + W3xC,W3
• And we have,
xA,D2 + xB,D2 + xC,D2 = 1
xA,S + xB,S + xC,S = 1
xA,W3 + xB,W3 + xC,W3 = 1
XC,D2 = 0; XA,W3 = 0

7.  Component Balance
• Component A
FZA = D2xA,D2 + SxA,S + W3xA,W3
1300 x 0.1096 = D2 x 0.99 + S x 0.01 + 0
• Component B
FZB = D2xB,D2 + SxB,S + W3xB,W3
1300 x 0.4214 = D2 x 0.01 + S x 0.98 + W3 x 0.01
• Component C
FZC = D2xC,D2 + SxC,S + W3xC,W3
1300 x 0.4687 = 0 + S x 0.03 + W3 x 0.97
On solving the above equations, we have,
D2 = 138.35 Kmol/hr
S = 551.35 Kmol/hr
W3 = 611.1025 Kmol/hr

8.  Material Balance
COMPONENT INLET OUTLET
Composition Molar Flow
(Kmol/hr)
Distillate
(Kmol/hr)
Side Product
(Kmol/hr)
Bottom
(Kmol/hr)
Benzene 0.1096 142.48 136.9665 5.5135 0
Toluene 0.4217 548.21 1.835 540.323 6.111025
P- Xylene 0.4687 609.31 0 18.33307 592.77

9.  Energy Balance
• Heat Capacity Equation
Heat Capacity can be expressed as Cp = A + BT + CT2 + DT3
• Reference Temperature: 298.15K
Heat capacity constants at reference temperature
COMPONENT HEAT CAPACITY CONSTANTS
A B C D
Benzene -33.893 471.793 x 10-
9
-2.98294 x e-4 70.823 x 10-9
Toluene -33.87 556.952 x 10-
3
342.3152 x
10-6
79.859 x 10-9
P-Xylene -25.09 0.6042 -3.374 x e-4 6.820 x e-8

10.  Energy Balance
• Energy Balance for feed
Temperature: 1350C; Pressure: 150 KPa; Molar Flow = 1300 Kmol/hr
Heat Capacity values at 408.15K
CPmix = Σ yiCP
Cpmix = yA CPA + yBCPB + ycCPC
= 0.1096 x 98.3691 + 0.4217 x 123.3254 + 0.4687 + 144.2845
= 130.4219 KJ/(Kmol.K)
We know that, Q = mCPΔT
Qf = FCpΔT
= 1300 x 130.4219 x (135-25) = 18650331.7 KJ/hr
COMPONENT COMPOSITION CP (KJ/Kmol. K)
Benzene 0.1096 98.3691
Toluene 0.4217 123.3254
P- Xylene 0.4687 144.2845

11.  Energy Balance for Distillate
• Temperature: 850C; Pressure = 150 Kpa; Molar Flow = 138.35 Kmol/hr
Heat capacity values at 850C
Cpmix = yA CPA + yBCPB + ycCPC
= 91.66443 KJ/(Kmol. K )
QD = DCp ΔT
= 138.35 x 91.66443 x (85-25)
= 760906.4334 KJ/hr
COMPONENT COMPOSITION CP (KJ/Kmol. K)
Benzene 0.9800 91.194
Toluene 0.0200 114.7155
P- Xylene 0.0000 135.1657

12.  Energy Balance for Bottom
• Temperature: 1420C; Pressure: 150KPa; Molar flow: 611.1025 Kmol/hr
Heat capacity values at 1420C
Cpmix = yA CPA + yBCPB + ycCPC
= 144.7148 KJ/(kmol. K)
QB = BCP ΔT
= 611.1025 x 144.7148 x (142-25)
=10346962.4 KJ/hr
COMPONENT COMPOSITION CP (KJ/Kmol. K)
Benzene 0.0000 99.2604
Toluene 0.0300 124.3301
P- Xylene 0.9700 145.3453

13.  Energy Balance for side stream
• Temperature: 117.230C; Pressure: 150 Kpa; Molar flow: 551.35 kmol/hr
Heat capacity values at 117.230C
Cpmix = yA CPA + yBCPB + ycCPC
= 121.4866 KJ/Kmol.K
QS = SCP ΔT
= 551.35 x 121.4866 x (117.23-25)
= 7852257.295 KJ/hr
COMPONENT COMPOSITION CP (KJ/Kmol. K)
Benzene 0.0100 95.9686
Toluene 0.9800 121.5009
P- Xylene 0.0100 145.6063

14.  Energy Balance for Condenser
Molecular weight and Latent heat of vaporization data
‫ג‬avg = Σ ‫ג‬iMi
n
= 32965.0133 KJ/kg
We know that,
L= R x D
= 23 x 138.35
= 3182.05 Kmol/hr
V = L + D
= 3182.05 + 138.35
= 3320.04 Kmol/hr
COMPONENT Molecular weight
(kg/kmol)
‫ג‬ value
(KJ/kg)
Benzene 78.11 390
Toluene 92.14 351
P- Xylene 106.15 340

15.  Energy Balance for condenser
HD = Cpavg(T-T0)
= 91.66443 x (85-25)
= 5499.658 KJ/mol
VHV = V[‫ג‬avg + HD]
= 3320.04 x [32965.0133 + 5499.658]
= 127704247.3 KJ/mol
DHD = 138.35 x 5499.658
= 760906.4334 KJ/hr
LHL = 3182.05 x 5499.658
= 17500186.74 KJ/hr
Qcondenser = VHV – DHD – LHL
= 127704247.3 – 760877.6843 – 17500186.74
= 109443182.9 KJ/hr

16.  Energy Balance for Reboiler
Qreboiler = QC + DHD +BHB + SHS – FHF
= 109752948.6 KJ/hr
• Overall Energy Balance
Total energy into the system – Total energy out of the system = 0
Total energy into the system = Qf + Qreboiler
= 18650331.7 + 109752948.6
= 128403280.3 KJ/hr
Total energy out of the system = Qcondenser + QD + Q S + QB
= 109443182.9 + 760877.6843 + 7852257.295 + 10346962.4
= 128403280.3 KJ/hr
Therefore, Energy into the system = Energy out of the system

17.  Future work
Specific Equipment Design
General Equipment Design
Materials of Construction
Health, Safety and Environmental Effects

18.  References
Asprion, N., Kaibel, G. (2010). Dividing wall columns: Fundamentals and recent advances. Chemical Engineering
and Processing: Process Intensidication.
Dejanović, I., Matijašević, L., & Olujić, Ž. (2010). Dividing wall column—a breakthrough towards sustainable
distilling. Chemical Engineering and Processing: Process Intensification.
Wright, R.O, 1946, Fractionation Apparatus, US patent No. 2471134, 1949.
Yildirim, Ö., Kiss, A. A., & Kenig, E. Y. (2011). Dividing wall columns in chemical process industry: A review on
current activities. Separation and Purification Technology.
Consider Dividing Wall Columns , by John G. Pendergast, David Vickery, Patrick Au-Yeung and Joe Anderson, The
Dow Chemical Company, Dec 19, 2008
http://seperationtechnology.com/dividing-wall-distillation/
https://www.researchgate.net/publication/243803667_A_Method_for_the_Design_of_Divided_Wall_Columns
https://www.researchgate.net/publication/315787212_Simulation_and_Analysis_of_Divided_Wall_Column_for_E
nergy_Efficient_and_Intensified_Distillation
 Smith J. M., Van Ness H. C., Abbott M M, ―Introduction to Chemical Engineering Thermo-dynamics‖, McGraw
Hill, 2005.
Designing a divided wall column-SAŠA POLOVINA, SRE´CKO HERCEG and ANA GRANI´ C ŠARACINA
https://pdfs.semanticscholar.org/a7e0/a3963b0456c617ee3805516ceed1c8f74b6d.pdf

19. Thank you..!!