2-1
CHAPTER 2
PROCESS FLOW DIAGRAM
2.1
MATERIAL BALANCE
2.1.1
INTRODUCTION
2-2
In order to produce 100000 MT of Ethylhexyl acrylate a year, the rate need to be achieved is 13888.89 kg/h or 72.368 kmole/h.
2.1.2
BALANCE IN MIXER AA: 6300kg/h 6300kg/h
M1
EHOL: 10050kg/h
M1 = AA + EHOL M1 = 6300kg/h + 10050kg/h M1 = 16350kg/h M1 = 164.5983kmole/h
2-3
Table 2.1.1: Flowrate 2.1.1: Flowrate for DC3-BOT and top DC4-TOP Stream.No Component Acrylic Acid EHOL EHA Water 1-Octene Diacrylic Acid
2.1.3
FDC3-BOT Flow Composition (kg/h) 0.0000 0.0000 0.0020 26.3889 0.9980 13168.0611 0.0000 0.0000
FDC4-TOP Flow Composition Composit ion (kg/h) 0.0000 0.0000 0.0020 1.3889 0.9980 693.0511 0.0000 0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
BALANCE ON REACTOR 0.5 kg C3H4O2 / kg kg 0.2 kg C8H18O / kg 0 kg C11H20O2 / kg 0.2 kg H2O / kg 0.1 kg C8H16 / kg 0 kg C6H8O4 / kg
DC3-TOP : 7104.704kg/h (1)
2-4
Table 2.1.2: Flowrate and composition for Reactor
Stream.No Componen t Acrylic Acid
FM1 Flow Compositio n
Flow (kmole/h )
Compositio n
87.3543
0.5000
77.2115 0.0000
0.2000 0.0000
EHOL EHA
0.6150 0.0000
6294.7500 6294.7500 10055.250 0 0.0000
Water 1-Octene Diacrylic Acid
0.0000 0.0000
0.0000 0.0000
0.0000 0.0000
0.2000 0.1000
(kg/h) 3,552.352 0 1,420.940 8 0.0000 1,420.940 8 710.4704
0.0000
0.0000
0.0000
0.0000
0.0000
0.3850
(kg/h)
FDC3-TOP Flow
FR-BOT Flow
Flow (kmole/h )
Compositio n
49.2971
0.4198
10.9110 0.0000
0.4893 0.0000
78.8535 6.3316 0.0000
(kg/h) 9847.102 0
Flow (kmole/h ) 136.651 4
0.0606 0.0303
11476.19 0.0000 1420.940 8 710.4704
88.1225 0.0000 78.8535 6.3316
0.0000
0.0000
0.0000
2-5
2.1.4
BALANCE ON DISTILLATION COLUMN
n kg C3H4O2 / kg n kg C8H18O / kg n kg C11H20O2 / kg n kg H2O / kg n kg C8H16 / kg n kg C6H8O4 / kg R-BOT
DC1-TOP = 20299.154kg/h
0.1750 kg C3H4O2 / kg 0.0713 kg C8H18O / kg 0.6487 kg C11H20O2 / kg 0.070 kg H2O / kg 0.0350 kg C8H16 / kg 0 kgC6H8O4/kg
DC2-BOT = 1273.706kg/h 0.6227 kg C3H4O2 / kg 0.1091 kg C8H18O / kg 0.1364 kg C11H20O2 / kg 0 kg H2O / kg 0.1318 kg C8H16 / kg 0 kg C6H8O4 / kg
DC1-BOT = 955.512kg/h
2-6
(R-BOT) + (DC2-BOT) = R (R-BOT) = R - (DC2-BOT) R-BOT = 21254.667kg/h -1273.706kg/h R-BOT = 19980.961kg/h
Table 2.1.3: Flowrate 2.1.3: Flowrate and composition for DC1 Stream.No
FDC2-BOT Flow Component Composition Composit ion (kg/h) Acrylic Acid 0.6227 793.1367 793.1367 EHOL 0.1091 138.9613 EHA 0.1364 173.7335 Water 0.0000 0.0000 1-Octene 0.1318 167.8745 Diacrylic Acid 0.0000 0.0000
FDC1-TOP
Flow (kmole/h) 11.0066 1.0670 0.9428 0.0000 1.4961 0.0000
FDC1-BOT Flow Composition Composit ion (kg/h) 0.0000 0.0000 0.0015 1.4333 0.7253 693.0329 0.0000 0.0000 0.0000 0.0000 0.2732
261.0459
FR-BOT
Flow (kmole/h) 0.0000 0.0110 3.7608 0.0000 0.0000 1.8112
2-7
0.26 kg C3H4O2 / kg 0.04kgC8H18O/k g 0.05 kg C11H20O2 / kg 0.57 kg H2O / kg 0.08 kg C8H16 / kg 0 kg C6H8O4 / kg R-TOP (1)
WASTEWATER (2)
0.05 kg C3H4O2 / kg 0 kg C8H18O / kg 0 kg C11H20O2 / kg 0.9 kg H2O / kg 0.05 kg C8H16 / kg 0 kg C6H8O4 / kg
DC2-BOT (3) n kg C3H4O2 / kg n kg C8H18O / kg n kg C11H20O2 / kg n kg H2O / kg n kg C8H16 / kg n kg C6H8O4 / kg
2-8
(1) = (2) + (3) (3) = 1273.706 kg/h
Table 2.1.4: Flowrate 2.1.4: Flowrate and composition for DC2 Stream.No Component Acrylic Acid EHOL EHA Water 1-Octene Diacrylic Acid
FR-TOP Flow Composition (kg/h) 0.2600 903.1734 0.0400 138.9498 0.0500 173.6872 0.5700 1980.0341 0.0800 277.8995 0.0000 0.0000
Flow (kmole/h) (kmole/h ) 12.5336 1.0670 0.9425 109.8798 2.4766 0.0000
FWASTEWATER Flow Flow Composition (kg/h) (kmole/h) (kmole/h ) 0.0500 110.0019 110.0019 1.5265 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.9000 1,980.0342 109.8798 0.0500 110.0019 0.9803 0.0000 0.0000 0.0000
FDC2-BOT Flow Flow Composition (kg/h) (kmole/h) 0.6227 793.1715 11.0071 0.1091 138.9498 1.0670 0.1364 173.6872 0.9425
2-9
DC3-TOP (2)
0.5 kg C3H4O2 / kg kg 0.2 kg C8H18O / kg 0 kg C11H20O2 / kg DC1-TOP (1)
n kg C3H4O2 / kg n kg C8H18O / kg n kg C11H20O2 / kg n kg H2O / kg n kg C8H16 / kg n kg C6H8O4 / kg
0.2kgH2O/kg 0.1 kg C8H16 / kg 0kgC6H8O4/ kg
DC3-BOT : 13194.45kg/h (3) 0kgC3H4O2/
2-10
x (1) = 0.35x (2) + 0.65x (3) x (1) = 0.35x (2) + 13194.45 0.65x = 13194.45 x
= 13194.45 / 0.65
x
= 20299.154kg/h
so, DC1-TOP = 20299.154kg/h
(1) = (2) + (3) 20299.154kg/h = (2) + 13194.45kg/h (2) = 7104.704kg/h so,
2-11
Table 2.1.5: Flowrate 2.1.5: Flowrate and composition for DC3 Stream.No Component Composition Acrylic Acid 0.0000 EHOL 0.0020 EHA 0.9980 Water 0.0000 1-Octene 0.0000 Diacrylic Acid 0.0000
FDC3-BOT
FDC3-TOP
Flow (kg/h) 0.0000 26.3889 13168.0611 0.0000 0.0000
Flow (kmole/h) 0.0000 0.2026 71.4568 0.0000 0.0000
Composition 0.5000 0.2000 0.0000 0.2000 0.1000
0.0000
0.0000
0.0000
FDC1-TOP Flow Composition (kg/h) 0.1750 3552.3520 0.0713 1447.3297 0.6487 13168.0611 0.0700 1420.9408 0.0350 710.4704 0.0000 0.0000
Flow (kg/h) 3,552.3520 3,552.3520 1,420.9408 0.0000 1,420.9408 710.4704
Flow (kmole/h) (kmole/h ) 49.2971 10.9110 0.0000 78.8535 6.3316
0.0000
0.0000
Flow (kmole/h) 49.2971 11.1136 71.4568 78.8535 6.3316 0.0000
2-12
DC4-TOP : 694.44kg/h (2)
0 kg C3H4O2 / kg 0.002 kg C8H18O / kg 0.998 kg C11H20O2 / kg DC1-BOT (1)
0 kg H2O / kg 0 kg C8H16 / kg 0 kg C6H8O4 / kg
n kg C3H4O2 / kg n kg C8H18O / kg n kg C11H20O2 / kg n kg H2O / kg n kg C8H16 / kg n kg C6H8O4 / kg
Heavies : (3) 0 kg C3H4O2 / kg 0 kg C8H18O / kg 0 kg C11H20O2 / kg 0 kg H2O / kg 0 kg C8H16 / kg 1 kg C6H8O4 / kg
2-13
Table 2.1.6: Flowrate 2.1.6: Flowrate and composition for DC4 Stream.No
FDC4-TOP
FHEAVIES
Flow
Flow (kmole/h) Composition
Flow
Flow
(kg/h)
(kmole/h)
Component Composition
(kg/h)
Acrylic Acid
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
EHOL
0.0020
1.3889
0.0107
0.0000
0.0000
0.0000
EHA
0.9980
693.0511
3.7609
0.0000
0.0000
0.0000
Water
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
1-Octene 1-Oct ene Diacrylic Acid
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
1.0000
261.0720
1.8114
FDC1-BOT Flow
Flow
Composition
(kg/h)
(kmole/h)
0.0000
0.0000
0.0000
0.0015
1.38888
0.0107
0.7253
693.0511
3.7609
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.2732
261.0720
1.8114
2-14
2.2.2
MANUAL ENERGY BALANCE CALCULATION Manual calculation for energy balances is made to determine the energy requirements of the processes, including heating, cooling and power required. The energy balances of the process are calculated using shortcut methods in Systematic Methods of Chemical Process Design (Biegler and Grossmann 1997) i.
No heat of mixing and pressure effect on ΔH
ii.
Neglect the potential and kinetic energy, and only consider the enthalpy change
iii.
Ideal properties are use in evaluating the stream energy
iv.
The system in an open system at steady state
v.
The linear velocities of all stream are the same
vi.
Since the effect of pressure pressure difference to the energy balance in the process gives a very small value as a compared to the values contributed by the sensible heat and the heat of formation, heat obtained from the pressure difference is assumed to be negligible. negligible.
2.2.3
ENERGY BALANCE CALCULATION CALCULATION METHOD
2-15
1-Octene
112.215
Diacrylic Acid
5.63E+01
4.07E-01
1.58E-04 -3.23E-07
1.06E-10
1.80E-05
1.75E-05
1.20E-03 -4.12E-05 1.0820E+02
(Sources: Chemical Properties Handbook, Perry’s Chemical Engineering Handbook, Elementary Principles of Chemical Processes.
b)
Heat Capacities Constant for Liquid Table 2.2.2: Heat capacities Constant for Liquid components components Liquid Liquid Heat Heat Capa Capacit cities ies,, Cp: aT+b aT+bT T +cT +d +dT T (kJ/m (kJ/mol) ol)
Components
A
B
C
D
Acrylic acid
8.42E+01
5.29E-01
-1.36E-03
0.0000E+00
2.09E+02
6.95E-01
-1.82E-03
-8.7346E+02
2-Ethylhexyl 2-Ethylh exyl Acrylate
1.97E+02 1 .97E+02
1.18E+00
-3.10E+03
0.0000E+00
Water
7.54E-02
0.00E+00
0.00E+00
0.0000E+00
2-Ethylhexanol 2-Ethylhexanol
2-16
2.2.4
GENERAL GENERAL EQUATIONS The process determined as an open system process. The general equation based on the first law of thermodynamics for an opened system.
Q-W S = ΔH + ΔEk + ΔEp
Equation above states that the net at which energy is transferred to a system as heat and /or shaft work (Q-W S) equal to the difference between at which the quantity (enthalpy + kinetic energy + potential energy) is transported into
and cut of the system (ΔH + ΔE k + ΔEp). Based on the assumptions stated above, W s = 0, ΔEk = 0, ΔEp = 0
Since the column has not been design yet in this process and all the work done by pump and the differences in pressure are neglected, the equation
2-17
2.2.6
ENTHALPIES ENTHALPIES FOR VAPOR MIXTURES
Methods suggested by Biegler et. Al in calculating enthalpies for vapor mixtures show as below:
ΔHv (T, y) = ΔHf + ΔHT = ΣkykHof, k (T1) +
(2)
Where Hf k (T 1) is the heat of formation for component k at T 1 and Cp is heat capacities for the component k.
2.2.7
ENTHALPIES ENTHALPIES FOR LIQUID MIXTURES MIXTURES
As for liquid phase, phase, the general formula is presented presented as below: below:
Σ
ΔHL (T, x) = ΔHf + ΔHT = ΣkxkHof, k (T1) +
kx k
ΔHkvap (T)
(3)
Where, ΔHvap is heat of vaporization of specific component as specific temperature. It could be found through the W aston Method:
2-18
2.2.8
ENERGY BALANCE CALCULATION CALCULATION Reference Conditions Tref = 25C @ 298 K Pref = 1 atm
2.2.8.1
COOLER
R-TOP
C1-DC2
Tin=358.15k Pin=29 kPa
Tout=338.15K
COOLER 1
Pout=29 kPa
Figure 2.2.1: Cooler 2.2.1: Cooler Inlet Stream R-TOP, Tin=358.15 K, vapor phase Outlet Stream C1-DC2, Tout=338.15K, liquid phase
2-19
ACRYLIC ACID i.
Balance at stream R-TOP
ΔĤR-Top =
Where
=
=
= 5.05E+03 kJ/mol
Δ HR-Top = m Δ ĤR-Top = (38.266) (5.05E+03)
2-20
ΔĤ C1-DC2ii =
Where
=
==
= -13892.24 kJ/mol
ΔĤ C1-DC2iii = Δ Hf = -3.24E+05 kJ/mol
Δ H C1-DC2 = m Δ Ĥ C1-DC2 = (38.266) (ΔĤ C1-DC2i + ΔĤ C1-DC2ii + ΔĤ C1-DC2iii)
2-21
2.2.8.2
CONVERSION REACTOR
Stream R-Top 358.15 K Stream M1-R 298.16 K Stream R-Bot 358.15 K
Figure 2.2.2: Inlet 2.2.2: Inlet and outlet streams of Conversion Reactor
Table 2.2.4: Enthalpy 2.2.4: Enthalpy of the t he streams at Conversion Reactor Inlet Stream M1-R Substances
ΔHin
Outlet Stream R-
Outlet Stream R-
Top
Bot ΔHout
ΔHout
2-22
ACRYLIC ACID i.
Balance at stream M1-R
ΔĤM1-Ra =
Where
=
=
=1.67E+00 kJ/ mol
Δ HM1-Ra = m Δ ĤM1-Ra = (87.435) (1.67E+00) = 145.72 kJ/hr
2-23
ΔĤR-Topaii =
Where
=
=
= -5263.01 kJ/mol
ΔĤR-Topaiii = Δ Hv = 42520.00
Δ HR-Topaiii = m Δ ĤR-Topaiii = (1.26E+01) (ΔĤR-Topai + ΔĤR-Topaii + ΔĤR-Topaiii)
2-24
=1.03E+04 kJ/mol
Δ HR-Bota = n Δ ĤR-Bota = (38.266) (1.03E+04) =395647.20kJ/hr
iv.
Energy for Conversion Conversion Reactor
Δ H= Δ Hour – Δ Hin = (Δ HTop + Δ HBot) – Δ HM1-R = (728250.99 + 395647.20) - 145.72 = -1.50E+12 kJ/hr Table 2.2.5: Enthalpy 2.2.5: Enthalpy of the streams of Conversion Reactor after calculation Substances
Inlet Stream M1-R
Outlet Stream R-Top
Outlet Stream R-Bot
2-25
2.2.8.3
DISTILLATION COLUMN
CONDENSER
CONDENSER
Stream Reflux 325.33 K
Stream to Condenser 378.85 K
REBOILER
Stream 11 325.33 K
REBOILER Stream 12 398.95 K
Stream to Reboiler 390.55 K
Figure 2.2.3: Inlet 2.2.3: Inlet and outlet streams of Distillation Column
Stream Boil Up 398.95 K
2-26
Table 2.2.7: Enthalpy 2.2.7: Enthalpy of the streams at Reboiler of Distillation Column Substances
Inlet Stream to Condenser nin kmol/hr
ΔHin kJ/hr
Outlet Stream Boil up nout kmol/hr
ΔHout kJ/hr
Outlet Stream 12 nout kmol/hr
ΔHout kJ/hr
Acrylic Acid
49.297
8.01E+05
38.266
2.36E+06
38.266
6.82E+05
2Ethylhexanol
11.125
1.03E+11
10.055
2.17E+11
10.055
1.05E+11
2-Ethylhexyl Acrylate
75.217
-2.57E+12
74.272
-6.94E+12
74.272
-2.84E+12
Water
78.854
5.49E+02
78.854
3.21E+06
78.854
5.99E+02
Octene
6.332
1.46E+05
4.832
2.87E+05
4.832
1.22E+05
Diacrylic Acid
1.772
2.86E+04 2. 86E+04
1.772
0.0
1.772
3.14E+04
2-27
Δ Hto Condensera = n Δ Ĥto Condensera = (49.297) (6.93E+03) =3.42E+05 kJ/hr
ii.
Balance at Stream Reflux
ΔĤRefluxi =
Where
=
=
=10308.06 kJ/mol
2-28
Δ HReflux = m Δ Ĥeflux = (1.26E+01) (ΔĤ Refluxi + ΔĤRefluxii + ΔĤRefluxiii) = (1.26E+01) (10308.06 + -16109.15 + -323.50) = -7.69E+04 kJ/hr
iii.
Balance at Stream 11
ΔĤ11 =
Where
=
=
= 2.21E+03 kJ/mol
2-29
i.
REBOILER
Balance at stream to reboiler
ΔĤto =
Where
=
=
=1.62E+04kJ/mol
Δ Hto reboiler = n Δ Ĥto reboiler = (49.297) (1.62E+04)
2-30
ΔĤBoil-upii =
Where
=
=
= -1478.59kJ/mol
ΔĤBoil-upiii = Δ Hv = 42520.00kJ/mol
Δ HBoil-up = m Δ ĤBoil-up = (38.266) (ΔĤ Boil-uoi + ΔĤBoil-upii + ΔĤBoil-upiii)
2-31
= 1.78E+04kJ/mol
Δ H12 = m Δ Ĥ12 = (38.266) (1.78E+04) = 6.82E+05kJ/hr
iv.
Energy for Reboiler
Δ H= Δ Hout – Δ Hin = (Δ HBoil-up + Δ H12) – Δ HReboiler = (2.36E+06 + 6.82E+05kJ) - 8.01E+05 = -6.69E+10 kJ/hr
2.2.8.4
PUMP
2-32
ΔP = Pout - Pin = 29 – 4 = 25 kpa Q =
Mass Flow(kg/h)
x 3600 s
Mass Density (kg/m3)
h
= 312484.6 m3/h
η =
(Q X ΔP) =28,933.76kJ/hr =104161519.7kW
2.2.9
SUMMARY OF ENERGY BALANCE CALCULATION FOR EACH EQUIPMENT Table 2.2.8: Summary 2.2.8: Summary of Energy for All Equipment Energy Equipment Name (kJ/hr)
2-33
-Boiler Pump 3
0.013324927kW
Distillation Column 3 -Condenser
-4.65E+11
-Boiler
-6.78E+12
Pump 5
0.068285kW
Distillation Column 4 -Condenser
1.86E+11
-Boiler
-1.19E+11
Cooler 2
2.72E+12
Pump 4
54701016.69 54701016.6 9
2-34
Distillation Distillatio n Column 4 Condenser
1.86E+11
7.62E+05
100.00
Distillation Distillati on Column 4 Reboiler
-1.19E+11 -1.19E+1 1
8.02E+05
100.00
Cooler 2
2.72E+12
2.91E+06
100.00
Pump 1
4.53E-02
4.53E-02
-0.13
Pump 2
9.10E-02
9.11E-02
-0.12
Pump 3
2.26E-03
1.33E-02
-488.82
Pump 4
5.63E-01
5.63E-01
0.01
Pump 5
8.04E-02
6.83E-02
15.04
From Table 2.2.9 above most of all equipment has an error. Mostly the errors are 100%. Some equipment has % error less than zero which is negative value. It is due to the decimal number during calculated calculated manually.
2.3
HYSYS SIMULATION
2-35
2.3.2
COMPONENT COMPONENT SELECTION
Component selection is the first step in simulating the ethylhexyl acrylate production plant. All the components involved in Hysys simulation are acrylic acid, ethylhexanol, ethylhexyl acrylate, water, diacrylic acid and also octene. All the six components are added to the Component list f rom the Component library.
2.3.3
FLUID PACKAGE
The selection of fluid package is important in Hysys. Selection of unsuitable fluid packaging will result in inaccurate result or the simulation will not be solved at all. The fluid packaging used in this Hysys simulation is UNIQUAC fluid packaging. It is found to be suitable for the esterification process.
2.3.4
REACTIONS
In this simulation process, conversion reactor is used with total conversion of 85%. 83% conversion is for the main reaction where product ethylhexyl acrylate is produced and 2 % is the conversion of the side reaction. There is only one set of
2-36
2.3.5
ADDING STREAMS
After components, fluid p ackage and reaction are assigned in the Simulation Basis Manager, the next step is to enter the simulation environment. In the simulation environment, the streams are added and correct specifications are entered to the streams. Only a few f ew specifications are entered without over specifying because error in consistency will occur when over specifying. Usually, basic parameters such as temperature, pressure and molar flow rate are chosen to b e entered in the streams. In this simulation, a total of 4 distillation columns, 1 conversion reactor, 2 mixers, 5 pumps, 2 cooler and 1 J-T valve are used in order to obtain the pure product of ethylhexyl acrylate. Feeds of 6300 kg/h acrylic acid and 10050 kg/h ethylhexanol are used to obtain 100000 metric ton per year of ethylhexyl acrylate.
2-37
Figure 2.3.1: Hysys 2.3.1: Hysys Simulation Process Flow Diagram
2-38
Table 2.3.1: Hysys 2.3.1: Hysys Workbook W orkbook Datasheet
2-39
2-40
