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 1 2006-06-20 17:33:53Z rafael $ |
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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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