Changeset 505 for branches/rate/eml/stage_separators/tray.mso

Timestamp:

Apr 18, 2008, 6:47:45 PM (15 years ago)

Author:

Gabriela Sporleder Straatmann

Message:

Adding non-equilibrium model for a tray.

File:

• branches/rate/eml/stage_separators/tray.mso (modified) (6 diffs)

branches/rate/eml/stage_separators/tray.mso

@@ -471 +471 @@
         "Liquid holdup"
         hl = (12*miL*a^2*uL/rhoL/g)^1/3;
+        
+        
 end
 
-Model trayRate
+#*-------------------------------------
+* Nonequilibrium Model
+-------------------------------------*#
+Model interface
+        
         ATTRIBUTES
         Pallete         = false;
@@ -479 +485 @@
         Brief           = "Basic equations of a tray column model.";
         Info            =
-"This model contains only the main equations of a column tray equilibrium model without
+"This model contains only the main equations of a column tray nonequilibrium model without
+the hidraulic equations.";
+
+        PARAMETERS
+outer PP as Plugin(Brief = "External Physical Properties", Type="PP");
+outer NComp as Integer;
+outer NC1 as Integer;
+        
+        VARIABLES
+        NL(NComp) as flux_mol   (Brief = "Stream Molar Flux Rate on Liquid Phase");
+        NV(NComp) as flux_mol   (Brief = "Stream Molar Flux Rate on Vapour Phase");
+        T as temperature                (Brief = "Stream Temperature");
+        P as pressure                   (Brief = "Stream Pressure");
+        x(NComp) as fraction    (Brief = "Stream Molar Fraction on Liquid Phase");
+        y(NComp) as fraction    (Brief = "Stream Molar Fraction on Vapour Phase");
+        a as area                           (Brief = "Interface Area");
+        htL as heat_trans_coeff (Brief = "Heat Transference Coefficient on Liquid Phase");
+        htV as heat_trans_coeff (Brief = "Heat Transference Coefficient on Vapour Phase");      
+        E_liq as heat_flux      (Brief = "Liquid Energy on interface");
+    E_vap as heat_flux      (Brief = "Vapour Energy on interface");     
+        hL as enth_mol          (Brief = "Liquid Molar Enthalpy");
+        hV as enth_mol          (Brief = "Vapour Molar Enthalpy");
+        ConcL as conc_mol       (Brief = "Liquid Molar Concentration");
+        ConcV as conc_mol       (Brief = "Vapour Molar Concentration");
+        kL(NC1,NC1) as velocity (Brief = "Mass Transfer Coefficients");
+        kV(NC1,NC1) as velocity (Brief = "Mass Transfer Coefficients");
+        
+        EQUATIONS
+        "Liquid Enthalpy"
+        hL = PP.LiquidEnthalpy(T, P, x);
+        
+        "Vapour Enthalpy"
+        hV = PP.VapourEnthalpy(T, P, y);
+
+end
+
+Model trayRate 
+        ATTRIBUTES
+        Pallete         = false;
+        Icon            = "icon/Tray"; 
+        Brief           = "Basic equations of a tray column model.";
+        Info            =
+"This model contains only the main equations of a column tray nonequilibrium model without
 the hidraulic equations.
         
 == Assumptions ==
 * both phases (liquid and vapour) exists all the time;
-* thermodymanic equilibrium with Murphree plate efficiency;
 * no entrainment of liquid or vapour phase;
 * no weeping;
@@ -493 +540 @@
 outer PP as Plugin(Brief = "External Physical Properties", Type="PP");
 outer NComp as Integer;
+    NC1 as Integer;
         V as volume(Brief="Total Volume of the tray");
         Q as heat_rate (Brief="Rate of heat supply"); 
@@ -499 +547 @@
         VARIABLES
 in      Inlet as stream (Brief="Feed stream", PosX=0, PosY=0.4932, Symbol="_{in}");
+in      InletFV as stream (Brief="Feed stream", PosX=0, PosY=0.4932, Symbol="_{in}");
 in      InletL as stream (Brief="Inlet liquid stream", PosX=0.5195, PosY=0, Symbol="_{inL}");
 in      InletV as stream (Brief="Inlet vapour stream", PosX=0.4994, PosY=1, Symbol="_{inV}");
@@ -504 +553 @@
 out     OutletV as vapour_stream (Brief="Outlet vapour stream", PosX=0.8043, PosY=0, Symbol="_{outV}");
 
-        M(NComp) as mol (Brief="Molar Holdup in the tray");
+        M_liq(NComp) as mol (Brief="Liquid Molar Holdup in the tray");
+        M_vap(NComp) as mol (Brief="Vapour 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");
+        E_liq as energy (Brief="Total Liquid Energy Holdup on tray");
+        E_vap as energy (Brief="Total Vapour Energy Holdup on tray");
         vL as volume_mol (Brief="Liquid Molar Volume");
         vV as volume_mol (Brief="Vapour Molar volume");
         Level as length (Brief="Height of clear liquid on plate");
-        yideal(NComp) as fraction;
-        Emv as Real (Brief = "Murphree efficiency");
+        interf as interface;    
         
         EQUATIONS
         "Component Molar Balance"
-        diff(M)=Inlet.F*Inlet.z + InletL.F*InletL.z + InletV.F*InletV.z
-                - OutletL.F*OutletL.z - OutletV.F*OutletV.z;
+        diff(M_liq)=Inlet.F*Inlet.z + InletL.F*InletL.z 
+        - OutletL.F*OutletL.z + interf.a*interf.NL;
+        
+        diff(M_vap)=InletFV.F*InletFV.z + InletV.F*InletV.z 
+        - OutletV.F*OutletV.z - interf.a*interf.NV;
         
         "Energy Balance"
-        diff(E) = ( Inlet.F*Inlet.h + InletL.F*InletL.h + InletV.F*InletV.h
-                - OutletL.F*OutletL.h - OutletV.F*OutletV.h + Q );
+        diff(E_liq) = Inlet.F*Inlet.h + InletL.F*InletL.h
+                - OutletL.F*OutletL.h  + Q + interf.a*interf.E_liq;
+        
+        diff(E_vap) = InletFV.F*InletFV.h + InletV.F*InletV.h
+                - OutletV.F*OutletV.h  - interf.a*interf.E_vap;
         
         "Molar Holdup"
-        M = ML*OutletL.z + MV*OutletV.z;
+        M_liq = ML*OutletL.z;
+        
+        M_vap = MV*OutletV.z;
         
         "Energy Holdup"
-        E = ML*OutletL.h + MV*OutletV.h - OutletL.P*V;
+        E_liq = ML*(OutletL.h - OutletL.P*vL);
+        
+        E_vap = MV*(OutletV.h - OutletV.P*vV);
+        
+        "Energy on interface"
+        interf.E_liq = interf.htL*(interf.T-OutletL.T)+sum(interf.NL)*interf.hL;        
+        
+        interf.E_vap = interf.htV*(OutletV.T-interf.T)+sum(interf.NV)*interf.hV;
+        
+        "Mass Conservation"
+        interf.NL=interf.NV;
+        
+        "Energy Conservation"
+        interf.E_liq = interf.E_vap;
+        
         
         "Mol fraction normalisation"
         sum(OutletL.z)= 1.0;
         sum(OutletL.z)= sum(OutletV.z);
+        sum(interf.x)=1.0;
+        sum(interf.x)=sum(interf.y);
         
         "Liquid Volume"
@@ -539 +613 @@
         
         "Chemical Equilibrium"
-        PP.LiquidFugacityCoefficient(OutletL.T, OutletL.P, OutletL.z)*OutletL.z = 
-                PP.VapourFugacityCoefficient(OutletV.T, OutletV.P, yideal)*yideal;
-
-        "Murphree Efficiency"
-        OutletV.z = Emv * (yideal - InletV.z) + InletV.z;
-        
-        "Thermal Equilibrium"
-        OutletV.T = OutletL.T;
-        
+        PP.LiquidFugacityCoefficient(interf.T, interf.P, interf.x)*interf.x = 
+                PP.VapourFugacityCoefficient(interf.T, interf.P, interf.y)*interf.y;
+
+        "Geometry Constraint"
+        V = ML*vL + MV*vV;
+        
+        "Level of clear liquid over the weir"
+        Level = ML*vL/Ap;
+        
+        "Total Mass Transfer Fluxes"
+        interf.NL(1:NC1)=interf.ConcL*sumt(interf.kL*(interf.x(1:NC1)-OutletL.z(1:NC1)))+
+                OutletL.z(1:NC1)*sum(interf.NL);
+        
+        interf.NV(1:NC1)=interf.ConcV*sumt(interf.kV*(OutletV.z(1:NC1)-interf.y(1:NC1)))+
+                OutletV.z(1:NC1)*sum(interf.NV);
+
         "Mechanical Equilibrium"
         OutletV.P = OutletL.P;
-        
-        "Geometry Constraint"
-        V = ML* vL + MV*vV;
-        
-        "Level of clear liquid over the weir"
-        Level = ML*vL/Ap;
+        interf.P=OutletL.P;
+        
+        SET   
+        NC1=NComp-1;
 end