Changeset 873 for branches/gui/eml/stage_separators/column.mso

Timestamp:

Oct 29, 2009, 3:47:18 PM (14 years ago)

Author:

gerson bicca

Message:

revised packed column

File:

• branches/gui/eml/stage_separators/column.mso (modified) (9 diffs)

branches/gui/eml/stage_separators/column.mso

@@ -84 +84 @@
         TopStageComposition(NComp)              as fraction     (Brief = "Component Molar Fraction at Top");
         BottomStageComposition(NComp)   as fraction     (Brief = "Component Molar Fraction at Bottom");
-        ColumnHoldup                                    as positive (Brief="Column holdup", Default=0.1);
+        ColumnHoldup                                    as positive (Brief = "Column holdup", Default=0.1);
 
 end
@@ -1745 +1745 @@
 Model Packed_Section_ColumnBasic
 
-
 ATTRIBUTES
         Pallete         = false;
@@ -1771 +1770 @@
         outer NComp     as Integer      (Brief="Number of components");
         
+        low_flow                as flow_mol     (Brief ="Low Flow",Default = 1E-6, Hidden=true);
+        low_pressure    as pressure     (Brief ="Low Pressure",Default = 1E-6, Hidden=true);
+        zero_flow               as flow_mol     (Brief ="No Flow",Default = 0, Hidden=true);
+        
         NumberOfFeeds                                           as Integer      (Brief="Number of Feed Stages",Default=3,Protected=true);
         NumberOfStages                                          as Integer      (Brief="Number of Stages", Default=3);
@@ -1785 +1788 @@
         Pi                              as constant             (Brief="Pi Number",Default=3.14159265, Symbol = "\pi",Hidden=true);
         Gconst                  as acceleration         (Brief="Gravity Acceleration",Default=9.81,Hidden=true);
-        hs                              as length                       (Brief="Height of the packing stage",Protected=true);
+        HETP                    as length                       (Brief="the Height Equivalent to a Theoretical Plate",Protected=true);
         ColumnArea              as area                         (Brief="Column Sectional Cross Area",Protected=true);
         
@@ -1805 +1808 @@
         
         STAGES(NumberOfStages) as packedStage;
-        PressureDrop               as pressure;
+        PressureDrop               as pressure (Brief="Column Pressure Drop", Protected=true);
         
 SET
         
         ColumnArea = 0.25*Pi*ColumnDiameter^2;
-        hs =PackingHeight/NumberOfStages;       
-        V = hs * ColumnArea;
+        HETP =PackingHeight/NumberOfStages;     
+        V = HETP * ColumnArea;
+        
+        low_pressure = 1E-4 * 'atm';
+        low_flow = 1E-6 * 'kmol/h';
+        zero_flow = 0 * 'kmol/h';
         
 CONNECTIONS
 
-        STAGES([2:NumberOfStages]).OutletVapour                 to STAGES([1:NumberOfStages-1]).InletVapour;
+        STAGES([2:NumberOfStages]).OutletVapour         to STAGES([1:NumberOfStages-1]).InletVapour;
         STAGES([1:NumberOfStages-1]).OutletLiquid       to STAGES([2:NumberOfStages]).InletLiquid;
-        LiquidConnector to STAGES(1).InletLiquid;
-        VapourConnector to STAGES(NumberOfStages).InletVapour;
+        LiquidConnector                                                         to STAGES(1).InletLiquid;
+        VapourConnector                                                         to STAGES(NumberOfStages).InletVapour;
 
 EQUATIONS
-
-"PresureDrop"
-        PressureDrop = STAGES(NumberOfStages).OutletLiquid.P - STAGES(1).OutletLiquid.P;
 
         LiquidConnector.F= LiquidInlet.F;
@@ -1849 +1853 @@
         VapourOutlet.z = STAGES(1).OutletVapour.z;
 
+"PressureDrop"
+        PressureDrop = STAGES(NumberOfStages).OutletLiquid.P - STAGES(1).OutletLiquid.P;
+
 for i in [1:NumberOfStages] do
 
@@ -1855 +1862 @@
         case "on":
 "Pressure drop and Vapor flow, Billet (4-58)"
-        #STAGES(i).deltaP/hs  = ResistanceCoeff*AreaPerPackingVol*STAGES(i).uV^2*STAGES(i).rhoV*STAGES(i).invK / (2*(VoidFraction-STAGES(i).hl)^3);
-#       STAGES(i).invK = (1 + (2*STAGES(i).dp/(3*ColumnDiameter*(1-VoidFraction))));
-
-        STAGES(i).deltaP/hs  = ResistanceCoeff *( 0.5*AreaPerPackingVol + 2/ColumnDiameter) * 1/((VoidFraction-STAGES(i).hl)^3) * (STAGES(i).uV^2) * STAGES(i).rhoV;
-        
-        #deltaP/hs  = ResistanceCoeff * (AreaPerPackingVol/2 + 2/ColumnDiameter) * 1/((VoidFraction-hl)^3) * (uV^2) * rhoV;
-
-
-        when STAGES(i).InletVapour.F < 1e-6 * 'kmol/h' switchto "off";
+        STAGES(i).deltaP/HETP  = ResistanceCoeff *( 0.5*AreaPerPackingVol + 2/ColumnDiameter) * 1/((VoidFraction-STAGES(i).hl)^3) * (STAGES(i).uV^2) * STAGES(i).rhoV;
+        
+        when STAGES(i).InletVapour.F < low_flow switchto "off";
         
         case "off":
-        STAGES(i).InletVapour.F = 0 * 'mol/s';
-        
-                when STAGES(i).deltaP > 1e-4 * 'atm' switchto "on";
-                
-end
-        
+"Vapour Flow"
+        STAGES(i).InletVapour.F = zero_flow;
+        
+        when STAGES(i).deltaP > low_pressure switchto "on";
+
+end
+
 "Energy Balance"
-        diff(STAGES(i).E) = ( STAGES(i).Inlet.F*STAGES(i).Inlet.h + STAGES(i).InletLiquid.F*STAGES(i).InletLiquid.h + STAGES(i).InletVapour.F*STAGES(i).InletVapour.h- STAGES(i).OutletLiquid.F*STAGES(i).OutletLiquid.h
+        diff(STAGES(i).E) = (STAGES(i).Inlet.F*STAGES(i).Inlet.h + STAGES(i).InletLiquid.F*STAGES(i).InletLiquid.h + STAGES(i).InletVapour.F*STAGES(i).InletVapour.h- STAGES(i).OutletLiquid.F*STAGES(i).OutletLiquid.h
         - STAGES(i).OutletVapour.F*STAGES(i).OutletVapour.h + HeatSupply );
-        
+
 "Energy Holdup"
         STAGES(i).E = STAGES(i).ML*STAGES(i).OutletLiquid.h + STAGES(i).MV*STAGES(i).OutletVapour.h - STAGES(i).OutletLiquid.P*V;
@@ -1883 +1885 @@
         
 "Volume flow rate of vapor, m^3/m^2/s"
-        #STAGES(i).uV * ((ColumnArea)*VoidFraction - STAGES(i).Al) = STAGES(i).OutletVapour.F * STAGES(i).vV;
-        STAGES(i).uV * ((ColumnArea)*VoidFraction - STAGES(i).Al) = STAGES(i).InletVapour.F * STAGES(i).vV;
-        
+        STAGES(i).uV * (V*VoidFraction/HETP - STAGES(i).Al) = STAGES(i).InletVapour.F * STAGES(i).vV;
+
 "Liquid holdup"
-        STAGES(i).hl = STAGES(i).ML*STAGES(i).vL/V/VoidFraction;
-        
-#"Particle diameter"
-#       STAGES(i).dp = 6 * (1-VoidFraction)/AreaPerPackingVol;
-        
-#"Wall Factor"
-#       STAGES(i).invK = (1 + (2*STAGES(i).dp/(3*ColumnDiameter*(1-VoidFraction))));
-        
-#"Reynolds number of the vapor stream"
-#       STAGES(i).Rev*STAGES(i).invK = STAGES(i).dp*STAGES(i).uV*STAGES(i).rhoV / (STAGES(i).miV*(1-VoidFraction));
-        
-#"Pressure drop and Vapor flow"
-#       STAGES(i).deltaP/hs  = ResistanceCoeff*AreaPerPackingVol*STAGES(i).uV^2*STAGES(i).rhoV*STAGES(i).invK / (2*(VoidFraction-STAGES(i).hl)^3);
-
-"Liquid holdup"
-        STAGES(i).hl = (12*STAGES(i).miL*AreaPerPackingVol^2*STAGES(i).uL/STAGES(i).rhoL/Gconst)^1/3;
+        STAGES(i).hl*V*VoidFraction = STAGES(i).ML*STAGES(i).vL;
+        
+"Liquid velocity as a function of liquid holdup, Billet (4-27)"
+        STAGES(i).hl^3 = (12/Gconst) * AreaPerPackingVol^2 * (STAGES(i).miL/STAGES(i).rhoL) * STAGES(i).uL;
+        #STAGES(i).hl = (12*STAGES(i).miL*AreaPerPackingVol^2*STAGES(i).uL/STAGES(i).rhoL/Gconst)^1/3;
 
 "Area occupied by the liquid"
-        STAGES(i).Al = STAGES(i).ML*STAGES(i).vL/hs;
+        STAGES(i).Al = STAGES(i).ML*STAGES(i).vL/HETP;
 
 end
@@ -1916 +1906 @@
         STAGES(i).OutletLiquid.T = INITIALIZATION.TopStageTemperature+(INITIALIZATION.BottomStageTemperature-INITIALIZATION.TopStageTemperature)*((i-1)/(NumberOfStages-1));
 
-"The Liquid Holdup of the STAGES"
+"The Column Holdup of the STAGES"
         STAGES(i).hl = INITIALIZATION.ColumnHoldup;