#*-------------------------------------------------------------------
* EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC.
*
* This LIBRARY is free software; you can distribute it and/or modify
* it under the therms of the ALSOC FREE LICENSE as available at
* http://www.enq.ufrgs.br/alsoc.
*
* EMSO Copyright (C) 2004 - 2007 ALSOC, original code
* from http://www.rps.eng.br Copyright (C) 2002-2004.
* All rights reserved.
*
* EMSO is distributed under the therms of the ALSOC LICENSE as
* available at http://www.enq.ufrgs.br/alsoc.
*
*-------------------------------------------------------------------
* Model of a dynamic reboiler
*--------------------------------------------------------------------
*
* Streams:
* * a liquid inlet stream
* * a liquid outlet stream
* * a vapour outlet stream
* * a feed stream
*
* Assumptions:
* * perfect mixing of both phases
* * thermodynamics equilibrium
* * no liquid entrainment in the vapour stream
*
* Specify:
* * the Feed stream
* * the Liquid inlet stream
* * the outlet flows: OutletV.F and OutletL.F
*
* Initial:
* * the reboiler temperature (OutletL.T)
* * the reboiler liquid level (Ll)
* * (NoComps - 1) OutletL (OR OutletV) compositions
*
*
*----------------------------------------------------------------------
* Author: Paula B. Staudt
* $Id: reboiler.mso 243 2007-04-16 17:19:39Z paula $
*--------------------------------------------------------------------*#
using "streams";
Model reboiler
PARAMETERS
outer PP as Plugin(Brief = "External Physical Properties", Type="PP");
outer NComp as Integer;
Across as area (Brief="Cross Section Area of reboiler");
V as volume (Brief="Total volume of reboiler");
VARIABLES
in Inlet as stream(Brief="Feed Stream");
in InletL as stream(Brief="Liquid inlet stream");
out OutletL as liquid_stream(Brief="Liquid outlet stream");
out OutletV as vapour_stream(Brief="Vapour outlet stream");
in Q as heat_rate (Brief="Heat supplied");
M(NComp) as mol (Brief="Molar Holdup in the tray");
ML as mol (Brief="Molar liquid holdup");
MV as mol (Brief="Molar vapour holdup");
E as energy (Brief="Total Energy Holdup on tray");
vL as volume_mol (Brief="Liquid Molar Volume");
vV as volume_mol (Brief="Vapour Molar volume");
Level as length (Brief="Level of liquid phase");
rhoV as dens_mass (Brief="Vapour Density");
EQUATIONS
"Component Molar Balance"
diff(M)= Inlet.F*Inlet.z + InletL.F*InletL.z
- OutletL.F*OutletL.z - OutletV.F*OutletV.z;
"Energy Balance"
diff(E) = Inlet.F*Inlet.h + InletL.F*InletL.h
- OutletL.F*OutletL.h - OutletV.F*OutletV.h + Q;
"Molar Holdup"
M = ML*OutletL.z + MV*OutletV.z;
"Energy Holdup"
E = ML*OutletL.h + MV*OutletV.h - OutletL.P*V;
"Mol fraction normalisation"
sum(OutletL.z)=1.0;
sum(OutletL.z)=sum(OutletV.z);
"Vapour Density"
rhoV = PP.VapourDensity(OutletV.T, OutletV.P, OutletV.z);
"Liquid Volume"
vL = PP.LiquidVolume(OutletL.T, OutletL.P, OutletL.z);
"Vapour Volume"
vV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z);
"Chemical Equilibrium"
PP.LiquidFugacityCoefficient(OutletL.T, OutletL.P, OutletL.z)*OutletL.z =
PP.VapourFugacityCoefficient(OutletV.T, OutletV.P, OutletV.z)*OutletV.z;
"Mechanical Equilibrium"
OutletL.P = OutletV.P;
"Thermal Equilibrium"
OutletL.T = OutletV.T;
"Geometry Constraint"
V = ML*vL + MV*vV;
"Level of liquid phase"
Level = ML*vL/Across;
end
#*----------------------------------------------------------------------
* Model of a Steady State reboiler with no thermodynamics equilibrium
*---------------------------------------------------------------------*#
Model reboilerSteady
PARAMETERS
outer PP as Plugin(Brief = "External Physical Properties", Type="PP");
outer NComp as Integer;
DP as press_delta (Brief="Pressure Drop in the reboiler");
VARIABLES
in InletL as stream(Brief="Liquid inlet stream");
out OutletV as vapour_stream(Brief="Vapour outlet stream");
in Q as heat_rate (Brief="Heat supplied");
vV as volume_mol (Brief="Vapour Molar volume");
rhoV as dens_mass (Brief="Vapour Density");
EQUATIONS
"Molar Balance"
InletL.F = OutletV.F;
InletL.z = OutletV.z;
"Vapour Volume"
vV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z);
"Vapour Density"
rhoV = PP.VapourDensity(OutletV.T, OutletV.P, OutletV.z);
"Energy Balance"
InletL.F*InletL.h + Q = OutletV.F*OutletV.h;
"Pressure"
DP = InletL.P - OutletV.P;
end
#*----------------------------------------------------------------------
* Model of a Steady State reboiler with fake calculation of
* vaporisation fraction and output temperature, but with a real
* calculation of the output stream enthalpy
*---------------------------------------------------------------------*#
Model reboilerSteady_fakeH
PARAMETERS
outer PP as Plugin(Brief = "External Physical Properties", Type="PP");
outer NComp as Integer;
DP as press_delta (Brief="Pressure Drop in the reboiler");
k as Real (Brief = "Flow Constant", Unit='mol/J');
VARIABLES
in InletL as stream(Brief="Liquid inlet stream");
out OutletV as stream(Brief="Vapour outlet stream");
in Q as heat_rate (Brief="Heat supplied");
EQUATIONS
"Molar Balance"
InletL.F = OutletV.F;
InletL.z = OutletV.z;
"Energy Balance"
InletL.F*InletL.h + Q = OutletV.F*OutletV.h;
"Pressure"
DP = InletL.P - OutletV.P;
"Fake Vapourisation Fraction"
OutletV.v = 1.0;
"Fake output temperature"
OutletV.T = 300*'K';
"Pressure Drop through the reboiler"
OutletV.F = k*Q;
end
#*-------------------------------------------------------------------
* Model of a dynamic reboiler with reaction
*-------------------------------------------------------------------*#
Model reboilerReact
PARAMETERS
outer PP as Plugin(Type="PP");
outer NComp as Integer;
Across as area (Brief="Cross Section Area of reboiler");
V as volume (Brief="Total volume of reboiler");
stoic(NComp) as Real(Brief="Stoichiometric matrix");
Hr as energy_mol;
Pstartup as pressure;
VARIABLES
in Inlet as stream(Brief="Feed Stream");
in InletL as stream(Brief="Liquid inlet stream");
out OutletL as liquid_stream(Brief="Liquid outlet stream");
out OutletV as vapour_stream(Brief="Vapour outlet stream");
Q as heat_rate (Brief="Heat supplied");
M(NComp) as mol (Brief="Molar Holdup in the tray");
ML as mol (Brief="Molar liquid holdup");
MV as mol (Brief="Molar vapour holdup");
E as energy (Brief="Total Energy Holdup on tray");
vL as volume_mol (Brief="Liquid Molar Volume");
vV as volume_mol (Brief="Vapour Molar volume");
Level as length (Brief="Level of liquid phase");
Vol as volume;
startup as Real;
rhoV as dens_mass;
r3 as reaction_mol (Brief = "Reaction resulting ethyl acetate", DisplayUnit = 'mol/l/s');
C(NComp) as conc_mol (Brief = "Molar concentration", Lower = -1);
EQUATIONS
"Molar Concentration"
OutletL.z = vL * C;
"Reaction"
r3 = exp(-7150*'K'/OutletL.T)*(4.85e4*C(1)*C(2) - 1.23e4*C(3)*C(4)) * 'l/mol/s';
"Component Molar Balance"
diff(M)= Inlet.F*Inlet.z + InletL.F*InletL.z
- OutletL.F*OutletL.z - OutletV.F*OutletV.z + stoic*r3*ML*vL;
"Energy Balance"
diff(E) = Inlet.F*Inlet.h + InletL.F*InletL.h
- OutletL.F*OutletL.h - OutletV.F*OutletV.h + Q + Hr * r3 * vL*ML;
"Molar Holdup"
M = ML*OutletL.z + MV*OutletV.z;
"Energy Holdup"
E = ML*OutletL.h + MV*OutletV.h - OutletL.P*V;
"Mol fraction normalisation"
sum(OutletL.z)=1.0;
"Liquid Volume"
vL = PP.LiquidVolume(OutletL.T, OutletL.P, OutletL.z);
"Vapour Volume"
vV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z);
"Vapour Density"
rhoV = PP.VapourDensity(OutletV.T, OutletV.P, OutletV.z);
"Level of liquid phase"
Level = ML*vL/Across;
Vol = ML*vL;
"Mechanical Equilibrium"
OutletL.P = OutletV.P;
"Thermal Equilibrium"
OutletL.T = OutletV.T;
"Geometry Constraint"
V = ML*vL + MV*vV;
"Chemical Equilibrium"
PP.LiquidFugacityCoefficient(OutletL.T, OutletL.P, OutletL.z)*OutletL.z =
PP.VapourFugacityCoefficient(OutletV.T, OutletV.P, OutletV.z)*OutletV.z;
sum(OutletL.z)=sum(OutletV.z);
end