[1] | 1 | #*------------------------------------------------------------------- |
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| 2 | * Model of a dynamic reboiler |
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| 3 | *-------------------------------------------------------------------- |
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| 4 | * |
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| 5 | * Streams: |
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| 6 | * * a liquid inlet stream |
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| 7 | * * a liquid outlet stream |
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| 8 | * * a vapour outlet stream |
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| 9 | * * a feed stream |
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| 10 | * |
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| 11 | * Assumptions: |
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| 12 | * * perfect mixing of both phases |
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| 13 | * * thermodynamics equilibrium |
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| 14 | * * no liquid entrainment in the vapour stream |
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| 15 | * |
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| 16 | * Specify: |
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| 17 | * * the Feed stream |
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| 18 | * * the Liquid inlet stream |
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| 19 | * * the outlet flows: OutletV.F and OutletL.F |
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| 20 | * |
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| 21 | * Initial: |
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| 22 | * * the reboiler temperature (OutletL.T) |
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| 23 | * * the reboiler liquid level (Ll) |
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| 24 | * * (NoComps - 1) OutletL (OR OutletV) compositions |
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| 25 | * |
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| 26 | * |
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| 27 | *---------------------------------------------------------------------- |
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| 28 | * Author: Paula B. Staudt |
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| 29 | * $Id: reboiler.mso 38 2006-10-23 20:26:39Z paula $ |
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| 30 | *--------------------------------------------------------------------*# |
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| 31 | |
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| 32 | using "streams"; |
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| 33 | |
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| 34 | Model reboiler |
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| 35 | PARAMETERS |
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| 36 | ext PP as CalcObject; |
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| 37 | ext NComp as Integer; |
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| 38 | Across as area (Brief="Cross Section Area of reboiler"); |
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| 39 | V as volume (Brief="Total volume of reboiler"); |
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| 40 | |
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| 41 | VARIABLES |
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| 42 | in Inlet as stream; # (Brief="Feed Stream"); |
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| 43 | in InletL as stream; # (Brief="Liquid inlet stream"); |
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| 44 | out OutletL as stream_therm; # (Brief="Liquid outlet stream"); |
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| 45 | out OutletV as stream_therm; # (Brief="Vapour outlet stream"); |
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| 46 | in Q as heat_rate (Brief="Heat supplied"); |
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| 47 | |
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| 48 | M(NComp) as mol (Brief="Molar Holdup in the tray"); |
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| 49 | ML as mol (Brief="Molar liquid holdup"); |
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| 50 | MV as mol (Brief="Molar vapour holdup"); |
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| 51 | E as energy (Brief="Total Energy Holdup on tray"); |
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| 52 | vL as volume_mol (Brief="Liquid Molar Volume"); |
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| 53 | vV as volume_mol (Brief="Vapour Molar volume"); |
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| 54 | Level as length (Brief="Level of liquid phase"); |
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| 55 | rhoV as dens_mass (Brief="Vapour Density"); |
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| 56 | |
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| 57 | EQUATIONS |
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| 58 | "Component Molar Balance" |
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| 59 | diff(M)= Inlet.F*Inlet.z + InletL.F*InletL.z |
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| 60 | - OutletL.F*OutletL.z - OutletV.F*OutletV.z; |
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| 61 | |
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| 62 | "Energy Balance" |
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| 63 | diff(E) = Inlet.F*Inlet.h + InletL.F*InletL.h |
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| 64 | - OutletL.F*OutletL.h - OutletV.F*OutletV.h + Q; |
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| 65 | |
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| 66 | "Molar Holdup" |
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| 67 | M = ML*OutletL.z + MV*OutletV.z; |
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| 68 | |
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| 69 | "Energy Holdup" |
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| 70 | E = ML*OutletL.h + MV*OutletV.h - OutletL.P*V; |
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| 71 | |
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| 72 | "Mol fraction normalisation" |
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| 73 | sum(OutletL.z)=1.0; |
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| 74 | sum(OutletL.z)=sum(OutletV.z); |
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| 75 | |
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| 76 | "Vapour Density" |
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| 77 | rhoV = PP.VapourDensity(OutletV.T, OutletV.P, OutletV.z); |
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| 78 | |
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| 79 | "Liquid Volume" |
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| 80 | vL = PP.LiquidVolume(OutletL.T, OutletL.P, OutletL.z); |
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| 81 | |
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| 82 | "Vapour Volume" |
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| 83 | vV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z); |
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| 84 | |
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| 85 | "Chemical Equilibrium" |
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| 86 | PP.LiquidFugacityCoefficient(OutletL.T, OutletL.P, OutletL.z)*OutletL.z = |
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| 87 | PP.VapourFugacityCoefficient(OutletV.T, OutletV.P, OutletV.z)*OutletV.z; |
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| 88 | |
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| 89 | "Mechanical Equilibrium" |
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| 90 | OutletL.P = OutletV.P; |
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| 91 | |
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| 92 | "Thermal Equilibrium" |
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| 93 | OutletL.T = OutletV.T; |
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| 94 | |
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| 95 | "Geometry Constraint" |
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| 96 | V = ML*vL + MV*vV; |
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| 97 | |
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| 98 | "Level of liquid phase" |
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| 99 | Level = ML*vL/Across; |
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| 100 | |
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| 101 | "vaporization fraction" |
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| 102 | OutletV.v = 1.0; |
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| 103 | OutletL.v = 0.0; |
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| 104 | end |
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| 105 | |
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| 106 | #*---------------------------------------------------------------------- |
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| 107 | * Model of a Steady State reboiler with no thermodynamics equilibrium |
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| 108 | *---------------------------------------------------------------------*# |
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| 109 | Model reboilerSteady |
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| 110 | PARAMETERS |
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| 111 | ext PP as CalcObject; |
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| 112 | ext NComp as Integer; |
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| 113 | DP as press_delta (Brief="Pressure Drop in the reboiler"); |
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| 114 | |
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| 115 | VARIABLES |
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| 116 | in InletL as stream; #(Brief="Liquid inlet stream"); |
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| 117 | out OutletV as stream_therm; #(Brief="Vapour outlet stream"); |
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| 118 | in Q as heat_rate (Brief="Heat supplied"); |
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| 119 | vV as volume_mol (Brief="Vapour Molar volume"); |
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| 120 | rhoV as dens_mass (Brief="Vapour Density"); |
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| 121 | |
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| 122 | EQUATIONS |
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| 123 | "Molar Balance" |
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| 124 | InletL.F = OutletV.F; |
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| 125 | InletL.z = OutletV.z; |
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| 126 | |
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| 127 | "Vapour Volume" |
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| 128 | vV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z); |
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| 129 | |
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| 130 | "Vapour Density" |
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| 131 | rhoV = PP.VapourDensity(OutletV.T, OutletV.P, OutletV.z); |
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| 132 | |
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| 133 | "Energy Balance" |
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| 134 | InletL.F*InletL.h + Q = OutletV.F*OutletV.h; |
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| 135 | |
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| 136 | "Pressure" |
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| 137 | DP = InletL.P - OutletV.P; |
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| 138 | |
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| 139 | "Vapourisation Fraction" |
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| 140 | OutletV.v = 1.0; |
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| 141 | end |
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| 142 | |
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[38] | 143 | #*------------------------------------------------------------------- |
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| 144 | * Model of a dynamic reboiler with reaction |
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| 145 | *-------------------------------------------------------------------*# |
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| 146 | Model reboilerReact |
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| 147 | PARAMETERS |
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| 148 | ext PP as CalcObject; |
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| 149 | ext NComp as Integer; |
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| 150 | Across as area (Brief="Cross Section Area of reboiler"); |
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| 151 | V as volume (Brief="Total volume of reboiler"); |
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| 152 | |
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| 153 | stoic(NComp) as Real(Brief="Stoichiometric matrix"); |
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| 154 | Hr as energy_mol; |
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| 155 | Pstartup as pressure; |
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| 156 | |
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| 157 | VARIABLES |
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| 158 | in Inlet as stream; #(Brief="Feed Stream"); |
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| 159 | in InletL as stream; #(Brief="Liquid inlet stream"); |
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| 160 | out OutletL as stream_therm; #(Brief="Liquid outlet stream"); |
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| 161 | out OutletV as stream_therm; #(Brief="Vapour outlet stream"); |
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| 162 | |
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| 163 | Q as heat_rate (Brief="Heat supplied"); |
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| 164 | M(NComp) as mol (Brief="Molar Holdup in the tray"); |
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| 165 | ML as mol (Brief="Molar liquid holdup"); |
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| 166 | MV as mol (Brief="Molar vapour holdup"); |
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| 167 | E as energy (Brief="Total Energy Holdup on tray"); |
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| 168 | vL as volume_mol (Brief="Liquid Molar Volume"); |
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| 169 | vV as volume_mol (Brief="Vapour Molar volume"); |
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| 170 | Level as length (Brief="Level of liquid phase"); |
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| 171 | Vol as volume; |
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| 172 | startup as Real; |
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| 173 | rhoV as dens_mass; |
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| 174 | r as reaction_mol (Brief = "Reaction resulting ethyl acetate", Unit = "mol/l/s"); |
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| 175 | C(NComp) as conc_mol (Brief = "Molar concentration", Lower = -1); |
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| 176 | |
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| 177 | EQUATIONS |
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| 178 | "Molar Concentration" |
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| 179 | OutletL.z = vL * C; |
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| 180 | |
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| 181 | "Component Molar Balance" |
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| 182 | diff(M)= Inlet.F*Inlet.z + InletL.F*InletL.z |
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| 183 | - OutletL.F*OutletL.z - OutletV.F*OutletV.z + stoic*r*ML*vL; |
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| 184 | |
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| 185 | "Energy Balance" |
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| 186 | diff(E) = Inlet.F*Inlet.h + InletL.F*InletL.h |
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| 187 | - OutletL.F*OutletL.h - OutletV.F*OutletV.h + Q + Hr * r * vL*ML; |
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| 188 | |
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| 189 | "Molar Holdup" |
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| 190 | M = ML*OutletL.z + MV*OutletV.z; |
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| 191 | |
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| 192 | "Energy Holdup" |
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| 193 | E = ML*OutletL.h + MV*OutletV.h - OutletL.P*V; |
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| 194 | |
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| 195 | "Mol fraction normalisation" |
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| 196 | sum(OutletL.z)=1.0; |
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| 197 | |
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| 198 | "Liquid Volume" |
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| 199 | vL = PP.LiquidVolume(OutletL.T, OutletL.P, OutletL.z); |
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| 200 | "Vapour Volume" |
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| 201 | vV = PP.VapourVolume(OutletV.T, OutletV.P, OutletV.z); |
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| 202 | "Vapour Density" |
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| 203 | rhoV = PP.VapourDensity(OutletV.T, OutletV.P, OutletV.z); |
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| 204 | |
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| 205 | "Level of liquid phase" |
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| 206 | Level = ML*vL/Across; |
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| 207 | |
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| 208 | Vol = ML*vL; |
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| 209 | |
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| 210 | "vaporization fraction " |
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| 211 | OutletV.v = 1.0; |
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| 212 | OutletL.v = 0.0; |
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| 213 | |
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| 214 | "Mechanical Equilibrium" |
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| 215 | OutletL.P = OutletV.P; |
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| 216 | |
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| 217 | "Thermal Equilibrium" |
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| 218 | OutletL.T = OutletV.T; |
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| 219 | |
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| 220 | "Geometry Constraint" |
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| 221 | V = ML*vL + MV*vV; |
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| 222 | |
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| 223 | "Chemical Equilibrium" |
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| 224 | PP.LiquidFugacityCoefficient(OutletL.T, OutletL.P, OutletL.z)*OutletL.z = |
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| 225 | PP.VapourFugacityCoefficient(OutletV.T, OutletV.P, OutletV.z)*OutletV.z; |
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| 226 | |
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| 227 | sum(OutletL.z)=sum(OutletV.z); |
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| 228 | |
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| 229 | end |
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