#*-------------------------------------------------------------------
* 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 46 2006-11-07 16:47:55Z paula $
*--------------------------------------------------------------------*#
using "streams";
Model reboiler
PARAMETERS
ext PP as CalcObject;
ext 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 stream_therm; # (Brief="Liquid outlet stream");
out OutletV as stream_therm; # (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;
"vaporization fraction"
OutletV.v = 1.0;
OutletL.v = 0.0;
end
#*----------------------------------------------------------------------
* Model of a Steady State reboiler with no thermodynamics equilibrium
*---------------------------------------------------------------------*#
Model reboilerSteady
PARAMETERS
ext PP as CalcObject;
ext 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 stream_therm; #(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;
"Vapourisation Fraction"
OutletV.v = 1.0;
end
Model reboilerSteady_fakeH
PARAMETERS
ext PP as CalcObject;
ext 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
ext PP as CalcObject;
ext 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 stream_therm; #(Brief="Liquid outlet stream");
out OutletV as stream_therm; #(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;
r as reaction_mol (Brief = "Reaction resulting ethyl acetate", Unit = "mol/l/s");
C(NComp) as conc_mol (Brief = "Molar concentration", Lower = -1);
EQUATIONS
"Molar Concentration"
OutletL.z = vL * C;
"Component Molar Balance"
diff(M)= Inlet.F*Inlet.z + InletL.F*InletL.z
- OutletL.F*OutletL.z - OutletV.F*OutletV.z + stoic*r*ML*vL;
"Energy Balance"
diff(E) = Inlet.F*Inlet.h + InletL.F*InletL.h
- OutletL.F*OutletL.h - OutletV.F*OutletV.h + Q + Hr * r * 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;
"vaporization fraction "
OutletV.v = 1.0;
OutletL.v = 0.0;
"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