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7/30/2019 Control Project 2 - Part 1
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Process Control - Project 2
By:- Eng. Sahar Nasrallah
Supervised by:- Dr Deeb Abu Fara
Simulation a Plant-Wide Control System Using MATLAB
http:www.mathworks.com
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Project Objective
Project Description -Reactor/Distillation Column Plant-
Dynamic Process Modeling
What is Simulink ?
How to solve ODE using Simulink? (Simple Example)
What is your task ?
Lecture Outline
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Project Objective The objective of the project is to practice simulation a
plant-wide control system.
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Project Description
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Project DescriptionA mixture of two species, mainly A but also containing
some B, is fed to a reactor where the reaction A B
takes place isothermally.
The binary distillation column (DC) has 20 stages.
DC produces two product streams: an overhead
(distillate) stream rich in A and a (bottom) stream rich in
the desired product B.
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Project DescriptionThe A-rich distillate is recycled to the reactor to
increase the conversion of A to B.
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Project DescriptionAn Isothermal Reactor:-
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Project DescriptionA Distillation Column:-
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Project DescriptionA number of simpli f ications are used here:
1. The reaction rate is first order in A (Elementary RXN).
2. Reactor operation is isothermal (T = 0).
3. The column operates with equimolal overflow (L=V).
4. Column operation is at atmospheric pressure.
5. Constant relative volatility is used to describe vapor/liquid
equilibrium.
6. Each tray represents an equilibrium stage
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Dynamic Process ModelingReactor:
General Information:
Reaction rate expression is first order in reactant A.
A B
rA = -kRHRz
Reactor residence time,HR (Fo + D) = 2.5 hr
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Dynamic Process ModelingrA : rxn rate ( reactant A consumption rate)
kR : Specific reaction rate (rate constant), 0.33 h-1
HR : Reactor holdup, 2400 lb-mol
z : DC feed composition, 0.5 mole fraction A
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Dynamic Process ModelingReactor:
Model:
1. Total (overall) Mass Balance:
Accumulation = Inlet - Outlet
= Fo+ D - F (= 0 for perfect reactor level/mols control)
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Dynamic Process ModelingHR : Reactor holdup, 2400 lb-mol
Fo : Fresh feed 460, Ib-mol/h
F : Column feed rate, 960 lb-mol
D : Distillate flow rate, 500 lb-mol
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Dynamic Process ModelingReactor:
Model:
2. Individual Component (A) Mass Balance:
Accumulation = Inlet - Outlet + disappearance
()
= F0z0+ DxD - Fz + (-kRHRz) (= 0 for perfect
reactor level/mols control)
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Dynamic Process Modelingz0 : Fresh feed composition, 0.9 mole fraction A
XD : Recycle composition, 0.95 mole fraction A
z : Column feed composition, 0.5 mole fraction A
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Dynamic Process ModelingDistillation Column:
General Information:
i. Saturated liquid feed is to 12th stage (of 20)
numbered from the top down.
ii. Equimolal overflow is assumed. A is the more volatile
component; assume equilibrium holds for each stage:
yi = ( )/(1+)
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Dynamic Process ModelingDistillation Column:
Drum Model:
1. Total (overall) Mass Balance:
Accumulation = InletOutlet + disappearance
()
= V-R-D (= 0 for perfect reactor level/mols control)
HD: Drum holdup 185 lb-mol
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Dynamic Process ModelingV : Vapor boilup, 1600 1 b-mol/h
R : Relux flow rate, 1100 Ib-mol/h
D : Distillate flow rate, 5001b-mol/h
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Dynamic Process ModelingDistillation Column:
Drum Model:
2. Individual Component (A) Mass Balance:
Accumulation = InletOutlet + disappearance
()
= V(y20)R(xD)D(xD) ( 0 for perfect reactor
level/mol control)
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Dynamic Process Modelingy20 : The A concentration in the vapor outlet from tray 20
upper trayyi =
1+= 0.974
: Relative volatility, =2
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Dynamic Process ModelingDistillation Column:
Stage i above feed Model:
1. Individual Component (A) Mass Balance:
Accumulation = InletOutlet + disappearance
xi()
= L(xi+1- xi )-V(yi - yi-1) for 13i 19
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Dynamic Process ModelingRectification Section
Hs: Individual stage holdup
Hs = 23.5 lb- mol
L=Li+1=Li=Li-1=R
V = Vi+1 = Vi = Vi-1
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Dynamic Process ModelingDistillation Column:
Feed Stage:
1. Individual Component (A) Mass Balance:
Accumulation = InletOutlet + disappearance
x12()
= L(x13- x12)-V(y12 - y11) + F z
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Dynamic Process Modelingwhere
L =L + F
L: Liquid hold up =
R, 1100 Ib-mol/h
F : Column feed rate, 960 lb-mol/h
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Dynamic Process ModelingDistillation Column:
Stage j below feed Model:
1. Individual Component (A) Mass Balance:
Accumulation = InletOutlet + disappearance
xj()
= L(xj+1- xj )-V(yj - yj-1) for 1 j11
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Dynamic Process ModelingStripping Section
Individual stage holdup,
Hs = 23.5 lb- mol
L=Lj+1=Lj=Lj-1=R+F =
L+F = 2060V = Vj+1 = Vj = Vj-1
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Dynamic Process ModelingDistillation Column:
Bioler Model:
1. Total (overall) Mass Balance:
Accumulation = InletOutlet + disappearance
()
= L-V-B (= 0 for perfect reactor level/mols control)
HB: Boiler holdup 275 lb-mol
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Dynamic Process ModelingL : L+F = 2060 lb-mollh
V : Vapor boilup, 1600 lb-mol/h
B : Bottoms flow rate, 4601 b-mol/h
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Dynamic Process ModelingDistillation Column:
Boiler Model:
2. Individual Component (A) Mass Balance:
Accumulation = InletOutlet + disappearance
()
= L(x1)V(yB)B(xB)
( 0 for perfect reactor level/mol control)
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What is Simulink ? What is the SIMULINK ?
1. Simulink is a tool for simulating dynamic systems with
a graphical interface specially developed for this purpose
within the MATLAB environment.
2. Simulink is a MATLAB toolbox that differs from the
other toolboxes, both in:
A. Its special interface .
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What is Simulink ? What is the SIMULINK ?
1. Simulink is a tool for simulating dynamic systems with
a graphical interface specially developed for this purpose
within the MATLAB environment.
2. Simulink is a MATLAB toolbox that differs from the
other toolboxes, both in:
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A. Its special interface .
B. Its special programmingtechnique .
C. The source code of the Simulink system is not open.
What is Simulink ?
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linear or nonlinear time-dependent processes (dynamic
systems that are continuous in time) can be described
using:
1. differential equations or (in the case of discrete times)
difference equations.
2. dynamic systems is with block diagrams, convert a
block diagram directly into Simulink and simulate the
operation of the system.
What is Simulink ?
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This is an attempt to understand the behavior of the
system by means of a graphical representation, which
essentially consists of representations of individual
components of the system together with the signal flowbetween these components.
What is Simulink ?
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Steps for solving Simulink problem :
1. Constructing a Simulink Block Diagram.
2. Parametrizing Simulink Blocks.
3. Simulink Simulation.
What is Simulink ?
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How to solve ODE using Simulink Example:
find the open loop response for the following of ODE
using Simulink toolbox.
=3+12
y(t) and x(t).
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How to solve ODE using Simulink Solution:
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How to solve ODE using Simulink
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What is you task ? Your task is to choose one or more of the alternatives
and perform simulation study using MATLAB
Simulink, to maintain the composition of B in the
product stream xB at the nominal value , 0.0105 mole
fraction, despite disturbances in the fresh feed
composition zO and the feed flow rate FO.
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Alternative 1 (Fig. 23.7a)
What is you task ?
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CSTR Model:
What is you task ?
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CSTR Model:
()
= F0z0+ DxD - Fz + (-kRHRz)
z()
+
()
= F0z0+ DxD - Fz + (-kRHRz)
()
=
[F0z0+ DxD Fz + (kRHRz)] z ()
where
()
= (Fo+D-F)
What is you task ?
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CSTR Model:
Inputs:
DFFoxD - zo
Outputs:
z - HR
What is you task ?
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Distillation Column Model:
What is you task ?
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CSTR-Distillation Column Model:
What is you task ?
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Thank You
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