Learn the fundamentals of any chemical process simulator software by means of free and open source software as an alternative to Aspen, Aspen HYSYS, etc. We will be using DWSIM (open source and free) and COCO Simulator (freeware) for this course. Material is licensed under CC BY-NC-SA 3.0.

1. INTRODUCTION TO CHEMICAL
PROCESS SIMULATORS
A. Carrero, N. Quirante, J. Javaloyes
October 2016
DWSIM Chemical Process Simulator

2. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
2
Contents
Monday, October 3rd 2016
 Introduction to Sequential – Modular Steady State Process
Simulators
 Get used to working with DWSIM and COCO
Monday, October 10th 2016
 Simulation of Chemical Reactors
Monday, October 17th 2016
 Simulation of Distillation Columns
Monday, October 24th 2016
 Case studies

3. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
3
Simulation of Distillation Columns
Feed
Distillate
Bottoms
Condenser
Reboiler
Rectifying section
Stripping section
Equilibrium Stage
Conventional
Distillation Column
Feed
Distillate
Bottoms

4. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
4
Simulation of Distillation Columns
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V
j
j
y
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j
i j
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j
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j
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z
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1
1
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y
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
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1
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
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jU
 
 
if from stage
if to stage
jQ


jW
Feed
Heat Transfer
Liquid
Side Stream
Vapor
Side Stream
Stage j

5. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
5
Simulation of Distillation Columns
jV
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if from stage
if to stage
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Feed
Heat Transfer
Liquid
Side Stream
Vapor
Side Stream
Stage j
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

Material Balance
Vapor-Liquid Equilibrium Relation
Summation Equations
Energy BalanceMESH Equations

6. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
6
Simulation of Distillation Columns
MESH Equations fully describe the behavior of a distillation column.
 External to de column: these equations define the overall column total
material balances, energy balances and product composition
 Internal to de column: they describe equilibrium conditions, internal
component, total material and energy balances in each tray.
 Bubble-point methods (BP)
 Sum-rate methods (SR)
 2N Newton methods
Nonlinear and Nonconvex algebraic system of equations
 Simultaneous correction methods (SC)
 Inside-out methods (IO)
Rigorous Computational Methods

7. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
7
Main Steps for the Simulation of a Conventional Distillation Column
# 1. Component Selection
# 2. Fluid package Selection
# 3. Flash Algorithm Selection
# 4. Add Distillation Column Object
# 5. Set Column Properties
 Condenser & Reboiler Pressure
 Condenser type
 Condenser & Reboiler Specifications
# 6. Set Number of Stages
# 7. Set Column Pressure Profile
# 8. Edit Column Connections
# 9. Solving Method Selection
# 10. Run Model
Simulation of Distillation Columns

8. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
8
Example
Molar Flow 200 kmol/h
Pressure 1.1 bar
Vapor fraction 0
Molar Composition
xBz = 0.35
xT = 0.29
xM-xy = 0.12
xO-xy = 0.12
xP-xy = 0.12
99% recovery of Bz
98% purity of Bz
Simulation of Distillation Columns

9. A. Carrero , N. Quirante & J. Javaloyes
Introduction to Chemical Process Simulators
9
Column Diameter Estimation
V L
LV
L V
ML
F
V M



 
 
0.2
2
2
exp 2.979 0.717ln 0.0865 ln
20
0.997ln 0.07973ln ln
0.256 ln
T LV LV
T LV T
T
K F F
H F H
H
        
 


L V
T F T
V
v f K
 



4 V
column
A V S T
M V
D
f f v 

FLV  Liquid-Vapor flow parameter
L, V  Liquid/Vapor molar flowrate [kmol s-1]
ML,MV  Liquid/Vapor molar mass [kg kmol-1]
L, V  Liquid/Vapor density [kg m-3]
KT  Parameter for terminal velocity [m s-1]
  Surface tension [dyne cm-1]
HT  Tray spacing [m] (0,25 – 0,6 m)
vT  Vapor flooding velocity [m s-1]
fF  Foaming factor
Low/ Moderate foaming ~ [0,9 - 0,85 ]
fA  Net area factor (~0,9)
fS  Flooding velocity safety factor (~0,8)
[R. Smith. Chemical Process Design and Integration]
[H. Kister. Distillation Design]