#*-------------------------------------------------------------------
* Model of a Batch Distillation (or Differential Distilation)
*-------------------------------------------------------------------- 
*
*	Streams:
*		* a liquid inlet stream
*		* a vapour outlet stream
*		* a inlet stream
*
*	Assumptions:
*		* perfect mixing of both phases
*		* thermodynamics equilibrium
*		* no liquid entrainment in the vapour stream
*
*	Specify:
*		* the inlet stream
*		* the liquid inlet stream
*		* the molar flow of the vapour outlet stream
*
*	Initial:
*		* the distillator temperature (T)
*		* the distillator liquid level (Ll)
*		* (NoComps - 1) compositions in the distillator
*					or in the OutletV
*		
*
*----------------------------------------------------------------------
* Author: Maurício Carvalho Maciel
* $Id: batch_dist.mso 1 2006-06-20 17:33:53Z rafael $
*--------------------------------------------------------------------*#
using "streams";
	
Model Diff_Dist
	
	PARAMETERS
ext PP 		as CalcObject	(Brief = "External Physical Properties");
ext NComp 	as Integer		(Brief = "Number of chemical components", Lower = 1);
	Across 	as area 		(Brief="Cross Section Area");
	V 		as volume 		(Brief="Total volume");
	
	VARIABLES
in	Inlet	as stream;		#(Brief="Feed stream");
in	InletL 	as stream;		#(Brief="Liquid inlet stream");
out	OutletV as stream_therm; #(Brief="Vapour outlet stream");

	M(NComp) 	as mol 			(Brief="Molar Holdup in the distillator");
	ML 			as mol 			(Brief="Molar liquid holdup");
	MV 			as mol 			(Brief="Molar vapour holdup");
	E 			as energy 		(Brief="Total Energy holdup on distillator");
	volL 		as volume_mol 	(Brief="Liquid Molar Volume");
	volV 		as volume_mol 	(Brief="Vapour Molar volume");
	Level		as length 		(Brief="Level of liquid phase", Default=1, Lower=0);
	T 			as temperature	(Brief="Temperature on distillator");
	P 			as pressure		(Brief="Pressure on distillator");
	x(NComp)	as fraction 	(Brief = "Molar Fraction of the Liquid of the distillator");
	h 			as enth_mol		(Brief="Molar Enthalpy of the liquid of the distillator");
	Q 			as heat_rate 	(Brief="Heat supplied");
	
	EQUATIONS
	
	"Component Molar Balance"
	diff(M)= Inlet.F*Inlet.z + InletL.F*InletL.z - OutletV.F*OutletV.z;
	
	"Energy Balance"
	diff(E) = Inlet.F*Inlet.h + InletL.F*InletL.h - OutletV.F*OutletV.h + Q;
	
	"Molar Holdup"
	M = ML*x + MV*OutletV.z; 
	
	"Energy Holdup"
	E = ML*h + MV*OutletV.h - P*V;
	
	"Mol fraction normalisation"
	sum(x)=1.0;
	sum(x)=sum(OutletV.z);

	"Liquid Volume"
	volL = PP.LiquidVolume(T, P, x);
	
	"Vapour Volume"
	volV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z);
	
	"Chemical Equilibrium"
	PP.LiquidFugacityCoefficient(T, P, x)*x = 
		PP.VapourFugacityCoefficient(OutletV.T, OutletV.P, OutletV.z)*OutletV.z;

	"Mechanical Equilibrium"
	P = OutletV.P;
	
	"Thermal Equilibrium"
	T = OutletV.T;
	
	"Geometry Constraint"
	V = ML*volL + MV*volV;
	
	"Level of liquid phase"
	Level = ML*volL/Across;
	
	"vaporization fraction "
	OutletV.v = 1.0;
	
	"Enthalpy"
	h = PP.LiquidEnthalpy(T, P, x);
	
end