Changeset 875 for branches/gui/eml/stage_separators/tray.mso

Timestamp:

Nov 3, 2009, 12:28:44 PM (13 years ago)

Author:

gerson bicca

Message:

packed column/tray revised

File:

• branches/gui/eml/stage_separators/tray.mso (modified) (4 diffs)

branches/gui/eml/stage_separators/tray.mso

@@ -281 +281 @@
 -------------------------------------*#
 Model packedStage
-        ATTRIBUTES
+
+ATTRIBUTES
         Pallete         = false;
-        Icon            = "icon/PackedStage"; 
         Brief           = "Complete model of a packed column stage.";
         Info            =
@@ -296 +296 @@
 * the liquid molar holdup ML
 * (NoComps - 1) OutletLiquid compositions
-";      
-        
+";
+
 PARAMETERS
 
-outer PP as Plugin(Brief = "External Physical Properties", Type="PP");
-outer NComp as Integer;
-
-        Mw(NComp)       as molweight    (Brief = "Component Mol Weight");
-        
-VARIABLES
-
-        Inlet                   as stream                               (Brief="Feed stream", PosX=0, PosY=0.4932, Symbol="_{in}");
-in      InletLiquid                     as stream                               (Brief="Inlet liquid stream", PosX=0.5195, PosY=0, Symbol="_{inL}");
-in      InletVapour                     as stream                               (Brief="Inlet vapour stream", PosX=0.4994, PosY=1, Symbol="_{inV}");
-out     OutletLiquid    as liquid_stream        (Brief="Outlet liquid stream", PosX=0.8277, PosY=1, Symbol="_{outL}");
-out     OutletVapour    as vapour_stream        (Brief="Outlet vapour stream", PosX=0.8043, PosY=0, Symbol="_{outV}");
-
-        M(NComp) as mol (Brief="Molar Holdup in the tray", Default=0.01, Lower=0, Upper=100);
-        ML as mol (Brief="Molar liquid holdup", Default=0.01, Lower=0, Upper=100);
-        MV as mol (Brief="Molar vapour holdup", Default=0.01, Lower=0, Upper=100);
-        E as energy (Brief="Total Energy Holdup on tray", Default=-500);
-        vL as volume_mol (Brief="Liquid Molar Volume");
-        vV as volume_mol (Brief="Vapour Molar volume");
-        
-        miL as viscosity (Brief="Liquid dynamic viscosity", DisplayUnit='kg/m/s');
-        rhoL as dens_mass;
-        rhoV as dens_mass;
-        
-        deltaP as pressure;
-        
-        uL as velocity (Brief="volume flow rate of liquid, m^3/m^2/s", Lower=-10, Upper=1000);
-        uV as velocity (Brief="volume flow rate of vapor, m^3/m^2/s", Lower=-10, Upper=1000);
-        Al as area (Brief="Area occupied by the liquid", Default=0.001, Upper=10);
-        hl as positive (Brief="Column holdup", Unit='m^3/m^3', Default=0.01,Upper=10);
+outer PP        as Plugin       (Brief = "External Physical Properties", Type="PP");
+outer NComp as Integer  (Brief = "Number Of Components");
+
+        LiquidResistanceCoeff   as positive     (Brief="Resistance coefficient on the liquid load", Default=1,Hidden=true);
+        AreaPerPackingVolume    as Real                 (Brief="surface area per packing volume", Unit='m^2/m^3',Hidden=true);
+        ColumnInternalDiameter  as length               (Brief="Column diameter",Hidden=true);
+        PackingVoidFraction             as Real                 (Brief="Void fraction of packing, (m^3 void space/m^3 packed bed)",Hidden=true);
+        HeightOfPacking                 as length               (Brief="Height of packing",Hidden=true);
+        Number_Stages                   as Integer              (Brief="Number of Stages", Default=3,Hidden=true);
+        HeatOnStage                     as heat_rate    (Brief="Rate of heat supply",Hidden=true);
+
+        HETP                    as length               (Brief="The Height Equivalent to a Theoretical Plate",Hidden=true);
+        ColumnArea              as area                 (Brief="Column Sectional Cross Area",Hidden=true);
+        V                               as volume               (Brief="Total Volume of the tray",Hidden=true);
+        Pi                              as constant     (Brief="Pi Number",Default=3.14159265, Symbol = "\pi",Hidden=true);
+        Gconst                  as acceleration (Brief="Gravity Acceleration",Default=9.81,Hidden=true);
+        
+        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);
+
+        Mw(NComp)       as molweight    (Brief = "Component Mol Weight",Hidden=true);
+        VapourFlow  as Switcher         (Brief = "Vapour Flow", Valid = ["on", "off"], Default = "on",Hidden=true);
 
 SET
         Mw = PP.MolecularWeight();
+        
+        ColumnArea      = 0.25*Pi*ColumnInternalDiameter^2;
+        HETP            = HeightOfPacking/Number_Stages;        
+        V                       = HETP * ColumnArea;
+        
+        low_pressure = 1E-4 * 'atm';
+        low_flow = 1E-6 * 'kmol/h';
+        zero_flow = 0 * 'kmol/h';
+
+VARIABLES
+
+        Inlet                   as stream                       (Brief="Feed stream", Symbol="_{in}",Protected=true);
+in      InletLiquid     as stream                       (Brief="Inlet liquid stream",  Symbol="_{inL}",Protected=true);
+in      InletVapour     as stream                       (Brief="Inlet vapour stream",  Symbol="_{inV}",Protected=true);
+out     OutletLiquid    as liquid_stream        (Brief="Outlet liquid stream", Symbol="_{outL}",Protected=true);
+out     OutletVapour    as vapour_stream        (Brief="Outlet vapour stream", Symbol="_{outV}",Protected=true);
+
+        M(NComp)        as mol                  (Brief="Molar Holdup in the tray", Default=0.01, Lower=0, Upper=100,Protected=true);
+        ML                      as mol                  (Brief="Molar liquid holdup", Default=0.01, Lower=0, Upper=100,Protected=true);
+        MV                      as mol                  (Brief="Molar vapour holdup", Default=0.01, Lower=0, Upper=100,Protected=true);
+        E                       as energy               (Brief="Total Energy Holdup on tray", Default=-500,Protected=true);
+        vL                      as volume_mol   (Brief="Liquid Molar Volume",Protected=true);
+        vV                      as volume_mol   (Brief="Vapour Molar volume",Protected=true);
+        miL             as viscosity    (Brief="Liquid dynamic viscosity", DisplayUnit='kg/m/s',Protected=true);
+        rhoL            as dens_mass    (Brief="Liquid mass density",Protected=true);
+        rhoV            as dens_mass    (Brief="Vapour mass density",Protected=true);
+        uL                      as velocity     (Brief="volume flow rate of liquid, m^3/m^2/s", Lower=-10, Upper=1000,Protected=true);
+        uV                      as velocity     (Brief="volume flow rate of vapor, m^3/m^2/s", Lower=-10, Upper=1000,Protected=true);
+        Al                      as area                 (Brief="Area occupied by the liquid", Default=0.001, Upper=10,Protected=true);
+        hl                      as positive     (Brief="Column holdup", Unit='m^3/m^3', Default=0.01,Upper=10,Protected=true);
+        deltaP          as pressure     (Brief="Stage Pressure drop",Protected=true);
 
 EQUATIONS
+
+switch VapourFlow
+        
+        case "on":
+"Pressure drop and Vapor flow, Billet (4-58)"
+        deltaP/HETP  = LiquidResistanceCoeff *( 0.5*AreaPerPackingVolume + 2/ColumnInternalDiameter) * 1/((PackingVoidFraction-hl)^3) * (uV^2) *rhoV;
+        
+        when InletVapour.F < low_flow switchto "off";
+        
+        case "off":
+"Vapour Flow"
+        InletVapour.F = zero_flow;
+        
+        when deltaP > low_pressure switchto "on";
+
+end
+
+"Energy Balance"
+        diff(E) = (Inlet.F*Inlet.h + InletLiquid.F*InletLiquid.h + InletVapour.F*InletVapour.h- OutletLiquid.F*OutletLiquid.h
+        - OutletVapour.F*OutletVapour.h + HeatOnStage );
+
+"Energy Holdup"
+        E = ML*OutletLiquid.h + MV*OutletVapour.h - OutletLiquid.P*V;
+
+"Geometry Constraint"
+        V*PackingVoidFraction= ML*vL + MV*vV;
+
+"Volume flow rate of vapor, m^3/m^2/s"
+        uV * (V*PackingVoidFraction/HETP - Al) = InletVapour.F * vV;
+
+"Liquid holdup"
+        hl*V*PackingVoidFraction = ML*vL;
+
+"Liquid velocity as a function of liquid holdup, Billet (4-27)"
+        hl^3 = (12/Gconst) * AreaPerPackingVolume^2 * (miL/rhoL) * uL;
+
+"Area occupied by the liquid"
+        Al = ML*vL/HETP;
 
 "Component Molar Balance"
@@ -341 +403 @@
 "Molar Holdup"
         M = ML*OutletLiquid.z + MV*OutletVapour.z;
-        
+
 "Mol Fraction Normalisation"
         sum(OutletLiquid.z)= 1.0;
@@ -376 +438 @@
         
 "Pressure Drop"
-        deltaP = InletVapour.P - OutletVapour.P;
+        deltaP = InletVapour.P - OutletVapour.P;        
 
 end