[748] | 1 | #*--------------------------------------------------------------------- |
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| 2 | * EMSO Model Library (EML) Copyright (C) 2004 - 2009 ALSOC. |
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| 3 | * |
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| 4 | * This LIBRARY is free software; you can distribute it and/or modify |
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| 5 | * it under the therms of the ALSOC FREE LICENSE as available at |
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| 6 | * http://www.enq.ufrgs.br/alsoc. |
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| 7 | * |
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| 8 | * EMSO Copyright (C) 2004 - 2009 ALSOC, original code |
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| 9 | * from http://www.rps.eng.br Copyright (C) 2002-2004. |
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| 10 | * All rights reserved. |
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| 11 | * |
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| 12 | * EMSO is distributed under the therms of the ALSOC LICENSE as |
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| 13 | * available at http://www.enq.ufrgs.br/alsoc. |
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| 14 | * |
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| 15 | *---------------------------------------------------------------------- |
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| 16 | * Equilibrium modeling of a biomass gasifier |
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| 17 | *---------------------------------------------------------------------- |
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| 18 | * |
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| 19 | * Description: |
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| 20 | * Thermodynamic equilibrium modeling of a biomass gasifier. |
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| 21 | * |
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| 22 | * Assumptions: |
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| 23 | * * thermodynamic equilibrium |
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| 24 | * * steady-state |
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| 25 | * * ideal gas relations |
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| 26 | * * ambient and atmospheric input conditions (To,Po) |
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| 27 | * * global gasification reaction: |
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| 28 | * CHONS + H2O + Air -> CO + CO2 + CH4 + H2 |
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| 29 | * + H2O + O2 + N2 + SO2 |
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| 30 | * * all oxygen is consumed in the process |
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| 31 | * |
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| 32 | * Specify: |
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| 33 | * * ultimate biomass analysis (dry.massfrac) |
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| 34 | * * moisture biomass ratio (moisture.massfrac) |
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| 35 | * * equivalence ratio (phi) |
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| 36 | * * relative air humidity (air.rh) |
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| 37 | * * equilibrium temperature (Teq) |
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| 38 | * |
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| 39 | *---------------------------------------------------------------------- |
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| 40 | * Author: Rodolfo Rodrigues and Argimiro R. Secchi |
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| 41 | * GIMSCOP/UFRGS - Group of Integration, Modeling, Simulation, |
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| 42 | * Control, and Optimization of Processes |
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| 43 | * LASIM/UFRGS - Simulation Laboratory |
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| 44 | * LPR/UFRGS - Residues Processing Laboratory |
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| 45 | * Federal University of Rio Grande do Sul |
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| 46 | * Porto Alegre (RS), Brazil |
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| 47 | * $Id$ |
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| 48 | *--------------------------------------------------------------------*# |
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| 49 | |
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| 50 | using "types"; |
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| 51 | |
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| 52 | |
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| 53 | #*--------------------------------------------------------------------- |
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| 54 | * Melhorias a fazer: |
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| 55 | * * adicionar o 'char' aos balanços de massa e energia; |
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| 56 | * * considerar a cinza nos balanços de massa e energia; |
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| 57 | * * adicionar cromo e cloro ao modelo; |
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| 58 | *--------------------------------------------------------------------*# |
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| 59 | |
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| 60 | |
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| 61 | |
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| 62 | #*--------------------------------------------------------------------- |
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| 63 | * Model of dry biomass |
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| 64 | *--------------------------------------------------------------------*# |
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| 65 | Model dry_biomass |
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| 66 | ATTRIBUTES |
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| 67 | Brief = "Model of dry biomass"; |
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| 68 | |
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| 69 | |
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| 70 | PARAMETERS |
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| 71 | NElem as Integer (Brief="Number of elements", Default=5); # CHONS... |
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| 72 | Mw_(NElem) as molweight(Brief="Molecular weight of elements"); |
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| 73 | |
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| 74 | HHVcalc as Switcher (Brief="High heat value calculation", |
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| 75 | Valid=["(Boie,1952)","(Zainal,2001)","(Higman,2003)","(Souza-Santos,2004)", |
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| 76 | "(Basu,2006)","Known data"], Default="(Souza-Santos,2004)"); |
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| 77 | |
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| 78 | |
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| 79 | SET |
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| 80 | NElem = 5; # C,H,O,N,S |
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| 81 | Mw_ = [12.011,1.0079,15.99994,14.0067,32.06]*'kg/kmol'; # C,H,O,N,S |
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| 82 | |
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| 83 | |
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| 84 | VARIABLES |
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| 85 | massfrac(NElem) as fraction (Brief="Mass fraction (Ultimate analysis)", Symbol="frac_{mass}", Unit='kg/kg'); |
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| 86 | molfrac(NElem) as fraction (Brief="Molar fraction", Symbol="frac_{mol}", Unit='kmol/kmol'); |
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| 87 | ash as fraction (Brief="Mass ash fraction", Unit='kg/kg'); # only used to HHV calculation |
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| 88 | Mw as molweight(Brief="Molecular weight"); |
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| 89 | |
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| 90 | F as flow_mol (Brief="Molar flow rate"); |
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| 91 | Fmass as flow_mass(Brief="Mass flow rate", Symbol="F_{mass}"); |
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| 92 | na(NElem) as positive (Brief="Matrix of elements"); |
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| 93 | H as enth_mol (Brief="Molar enthalpy"); |
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| 94 | Hmass as enth_mass(Brief="Mass enthalpy", Upper=1e9, Symbol="H_{mass}"); |
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| 95 | HHV as enth_mass(Brief="Mass high heat value", Symbol="HHV_{mass}", Upper=1e10); |
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| 96 | HHV_ as enth_mass(Brief="Known data for high heat value", Upper=1e10); |
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| 97 | HHVmol as enth_mol (Brief="Molar high heat value", Symbol="HHV_{mol}"); |
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| 98 | LHV as enth_mass(Brief="Mass low heat value", Upper=1e9, Symbol="LHV_{mass}"); |
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| 99 | LHVmol as enth_mol (Brief="Molar low heat value", Symbol="LHV_{mol}"); |
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| 100 | |
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| 101 | |
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| 102 | EQUATIONS |
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| 103 | "Molar fraction of fuel formula" |
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| 104 | na = massfrac*Mw_(1)/massfrac(1)/Mw_; |
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| 105 | |
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| 106 | "Mass fraction normalisation" |
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| 107 | sum(massfrac) = 1; |
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| 108 | |
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| 109 | "Molecular weight of fuel formula" |
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| 110 | Mw = sum(Mw_*na); |
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| 111 | |
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| 112 | "Molar fraction of biomass" |
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| 113 | molfrac = na/sum(na); |
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| 114 | |
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| 115 | "Mass flow rate" |
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| 116 | Fmass = F*Mw; |
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| 117 | |
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| 118 | "Molar enthalpy" |
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| 119 | Hmass*Mw = H; |
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| 120 | |
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| 121 | switch HHVcalc # CHONSA |
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| 122 | case "(Boie,1952)": |
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| 123 | "Equation of Boie" |
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| 124 | HHV = sum([35.16,116.225,11.09,6.28,10.465]*massfrac)*'kJ/kg'; |
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| 125 | |
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| 126 | case "(Zainal,2001)": |
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| 127 | "Reed and Levie (1985)" |
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| 128 | HHVmol = (sum([34.0945,13.23,-11.986,0,0]*massfrac/(1+ash)) - 1.53*ash + 6.85)*'kJ/kmol'; |
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| 129 | |
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| 130 | case "(Higman,2003)": |
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| 131 | "Dulong formula" |
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| 132 | HHV = (sum([34.91,117.83,-10.34,-1.51,10.05]*massfrac/(1+ash)) - 2.11*ash)*'MJ/kg'; |
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| 133 | |
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| 134 | case "(Souza-Santos,2004)": |
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| 135 | "Souza-Santos (2004)" |
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| 136 | HHV = (sum([34.245,110.198,-11.985,-11.985,0]*massfrac/(1+ash)) - 1.53*ash + 0.0685)*'MJ/kg'; |
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| 137 | |
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| 138 | case "(Basu,2006)": |
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| 139 | "Dulong and Petit formula" |
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| 140 | HHV = sum([33.823,144.25,-14.28,0,9.418]*massfrac)*'MJ/kg'; |
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| 141 | |
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| 142 | case "Known data": |
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| 143 | "Known data" |
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| 144 | HHV = HHV_; |
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| 145 | end |
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| 146 | |
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| 147 | |
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| 148 | "Molar high heat value" |
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| 149 | HHVmol = HHV*Mw; |
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| 150 | |
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| 151 | "Molar low heat value" |
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| 152 | LHVmol = LHV*Mw; |
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| 153 | end |
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| 154 | |
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| 155 | |
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| 156 | |
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| 157 | #*--------------------------------------------------------------------- |
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| 158 | * Model of moisture biomass |
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| 159 | *--------------------------------------------------------------------*# |
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| 160 | Model moisture_biomass |
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| 161 | ATTRIBUTES |
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| 162 | Brief = "Model of moisture biomass"; |
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| 163 | |
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| 164 | |
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| 165 | PARAMETERS |
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| 166 | # NComp as Integer (Brief="Number of components", Default=8); |
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| 167 | Mw as molweight(Brief="Molecular weight"); |
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| 168 | |
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| 169 | Ho as enth_mol (Brief="Molar standard enthalpy of formation"); |
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| 170 | Hv as enth_mol (Brief="Molar enthalpy of vaporization"); |
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| 171 | |
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| 172 | # Ho(NComp) as enth_mol (Brief="Molar standard enthalpy of formation"); |
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| 173 | # Hv(NComp) as enth_mol (Brief="Molar enthalpy of vaporization"); |
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| 174 | # Tb(NComp) as temperature (Brief="Boiling point temperature"); |
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| 175 | |
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| 176 | |
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| 177 | SET |
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| 178 | # NComp = 8; #PP.NumberOfComponents; |
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| 179 | Mw = 18.0152*'kg/kmol'; # H2O |
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| 180 | |
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| 181 | Ho = -2.42e5*'kJ/kmol'; #PP.IdealGasEnthalpyOfFormationAt25C(); |
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| 182 | Hv = 4.065e4*'kJ/kmol'; #PP.IdealGasEnthalpyOfFormation(Tb); |
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| 183 | # Tb = PP.NormalBoilingPoint(); |
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| 184 | |
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| 185 | |
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| 186 | VARIABLES |
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| 187 | F as flow_mol (Brief="Molar flow rate"); |
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| 188 | Fmass as flow_mass(Brief="Mass flow rate", Symbol="F_{mass}"); |
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| 189 | molfrac as positive (Brief="Molar relative moisture of biomass", Symbol="frac_{mol}", Unit='kmol/kmol'); |
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| 190 | massfrac as positive (Brief="Mass relative moisture of biomass", Symbol="frac_{mass}", Unit='kg/kg', Default=0.1); |
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| 191 | H as enth_mol (Brief="Molar enthalpy"); |
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| 192 | Hmass as enth_mass(Brief="Mass enthalpy", Lower=-1e9, Symbol="H_{mass}"); |
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| 193 | |
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| 194 | |
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| 195 | EQUATIONS |
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| 196 | "Mass flow rate" |
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| 197 | Fmass = F*Mw; |
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| 198 | |
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| 199 | "Mole enthalpy" |
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| 200 | H = Ho + Hv; |
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| 201 | |
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| 202 | "Mass enthalpy" |
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| 203 | Hmass*Mw = H; |
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| 204 | end |
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| 205 | |
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| 206 | |
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| 207 | |
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| 208 | #*--------------------------------------------------------------------- |
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| 209 | * Model of a biomass feed |
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| 210 | *--------------------------------------------------------------------*# |
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| 211 | Model raw_biomass |
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| 212 | ATTRIBUTES |
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| 213 | Brief = "Model of a biomass feed"; |
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| 214 | |
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| 215 | |
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| 216 | PARAMETERS |
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| 217 | To as temperature (Brief="Ambient temperature", Default=298); |
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| 218 | Po as pressure (Brief="Atmospheric pressure", Default=1); |
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| 219 | |
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| 220 | |
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| 221 | VARIABLES |
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| 222 | dry as dry_biomass (Brief="Dry biomass", Symbol="_{dry}"); |
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| 223 | moisture as moisture_biomass (Brief="Moisture biomass", Symbol="_{moist}"); |
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| 224 | |
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| 225 | F as flow_mol (Brief="Molar flow rate"); |
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| 226 | Fmass as flow_mass (Brief="Mass flow rate", Symbol="F_{mass}"); |
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| 227 | Mw as molweight (Brief="Molecular weight"); |
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| 228 | |
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| 229 | h as enth_mol (Brief="Molar enthalpy"); |
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| 230 | hmass as enth_mass (Brief="Mass enthalpy", Upper=1e9, Symbol="H_{mass}"); |
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| 231 | T as temperature (Brief="Temperature"); |
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| 232 | |
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| 233 | |
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| 234 | EQUATIONS |
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| 235 | "Molecular weight" |
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| 236 | Mw = (1 - moisture.molfrac)*dry.Mw + moisture.molfrac*moisture.Mw; |
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| 237 | |
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| 238 | "Molar fraction of moisture" # kmol of M by kmol of B |
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| 239 | moisture.molfrac*(moisture.massfrac+(1 - moisture.massfrac)*moisture.Mw/dry.Mw) = |
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| 240 | moisture.massfrac; |
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| 241 | |
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| 242 | "Dry biomass flow rate" |
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| 243 | dry.Fmass = (1 - moisture.massfrac)*Fmass; |
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| 244 | |
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| 245 | "Moisture biomass flow rate" |
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| 246 | moisture.Fmass = moisture.massfrac*Fmass; |
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| 247 | |
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| 248 | "Raw biomass flow rate" |
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| 249 | Fmass = F*Mw; |
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| 250 | |
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| 251 | "Mass enthalpy" |
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| 252 | hmass = (1 - moisture.massfrac)*dry.Hmass + moisture.massfrac*moisture.Hmass; |
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| 253 | |
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| 254 | "Mole enthalpy" |
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| 255 | h = hmass*Mw; |
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| 256 | |
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| 257 | "Mass low heat value" ## adicionado de 'stream_feed' |
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| 258 | dry.LHV = dry.HHV - moisture.Hv*dry.massfrac(2)/2/dry.Mw_(2); # (Souza-Santos,2004) |
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| 259 | # dry.LHV = (dry.HHV*(1-moisture.massfrac) |
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| 260 | # - moisture.Hv*moisture.massfrac - (1-.moisture.massfrac)) |
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| 261 | # *(18*dry.massfrac(2)/200); # (Mansaray,1998) p.26 -> ????? |
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| 262 | |
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| 263 | # dry.LHV = dry.HHV - 22604*'kJ/kg'*dry.massfrac(2) |
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| 264 | # - 2581*'kJ/kg'*moisture.massfrac; # (Basu,2006) p.449 |
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| 265 | |
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| 266 | "Temperature" |
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| 267 | T = To; |
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| 268 | end |
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| 269 | |
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| 270 | |
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| 271 | |
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| 272 | #*--------------------------------------------------------------------- |
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| 273 | * Model of an air stream |
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| 274 | *--------------------------------------------------------------------*# |
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| 275 | Model air_stream |
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| 276 | ATTRIBUTES |
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| 277 | Brief = "Model of an air stream"; |
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| 278 | |
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| 279 | |
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| 280 | PARAMETERS |
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| 281 | outer PP as Plugin (Brief="External physical properties", Type="PP"); |
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| 282 | NComp as Integer (Brief="Number of components", Default=8); |
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| 283 | Mw(NComp) as molweight; |
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| 284 | |
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| 285 | To as temperature (Brief="Ambient temperature", Default=298); |
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| 286 | Po as pressure (Brief="Atmospheric pressure", Default=1); |
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| 287 | |
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| 288 | |
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| 289 | VARIABLES |
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| 290 | F as flow_mol (Brief="Molar flow rate"); |
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| 291 | Fmass as flow_mass(Brief="Mass flow rate", Symbol="F_{mass}"); |
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| 292 | Fvol as flow_vol (Brief="Volumetric flow rate", Symbol="F_{vol}"); |
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| 293 | |
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| 294 | z(NComp) as fraction (Brief="Molar fraction", Unit='kmol/kmol'); |
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| 295 | zmass(NComp)as fraction (Brief="Mass fraction", Unit='kg/kg', Symbol="z_{mass}"); |
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| 296 | |
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| 297 | sh as positive (Brief="Specific humidity", Unit='g/kg'); |
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| 298 | rh as percent (Brief="Relative humidity"); |
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| 299 | |
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| 300 | Mws as molweight; |
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| 301 | vm as volume_mol; |
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| 302 | T as temperature; |
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| 303 | P as pressure; |
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| 304 | Pv(NComp) as pressure; |
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| 305 | h as enth_mol; |
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| 306 | |
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| 307 | |
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| 308 | SET |
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| 309 | NComp = 8; # PP.NumberOfComponents; |
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| 310 | Mw = PP.MolecularWeight(); |
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| 311 | |
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| 312 | |
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| 313 | EQUATIONS |
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| 314 | "Mixture Molecular weight" |
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| 315 | Mws = sum(z*Mw); |
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| 316 | |
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| 317 | "Mass flow rate" |
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| 318 | Fmass = F*Mws; |
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| 319 | |
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| 320 | "Volumetric flow rate" |
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| 321 | Fvol = F*vm; |
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| 322 | |
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| 323 | "Temperature" |
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| 324 | T = To; |
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| 325 | |
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| 326 | "Pressure" |
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| 327 | P = Po; |
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| 328 | |
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| 329 | |
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| 330 | "Molar Volume" |
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| 331 | vm = PP.VapourVolume(T,P,z); |
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| 332 | |
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| 333 | |
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| 334 | "Mass water fraction" |
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| 335 | zmass(1) = sh; |
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| 336 | |
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| 337 | "Mass oxygen fraction" |
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| 338 | zmass(2) = 0.2316*(1-zmass(1)); # (Basu,2006) p.446: 23.16% O2, 76.8% N2, 0.04% inerts |
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| 339 | |
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| 340 | "Mass nitrogen fraction" |
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| 341 | sum(zmass) = 1; |
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| 342 | |
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| 343 | "Air composition" # <<--- |
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| 344 | z(4:NComp) = 0; |
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| 345 | # zmass(4:8) = 0; |
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| 346 | |
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| 347 | "Molar fraction" |
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| 348 | z*sum(zmass/Mw) = zmass/Mw; |
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| 349 | |
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| 350 | "Relative humidity" |
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| 351 | rh = z(1)*P/Pv(1)*100; |
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| 352 | |
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| 353 | "Vapour pressure" |
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| 354 | Pv = PP.VapourPressure(T); |
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| 355 | |
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| 356 | "Enthalpy" |
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| 357 | h = sum(PP.IdealGasEnthalpyOfFormationAt25C()*z) + PP.VapourEnthalpy(T,P,z); |
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| 358 | end |
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| 359 | |
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| 360 | |
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| 361 | |
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| 362 | Model stream_gasifier |
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| 363 | ATTRIBUTES |
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| 364 | Brief = "Model of a gasifier stream"; |
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| 365 | |
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| 366 | |
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| 367 | PARAMETERS |
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| 368 | outer PP as Plugin (Brief="External physical properties", Type="PP"); |
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| 369 | NComp as Integer (Brief="Number of components", Default=8); |
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| 370 | NElem as Integer (Brief="Number of elements", Default=5); |
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| 371 | na(NElem,NComp)as positive(Brief="Matrix of elements per component"); |
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| 372 | Mw(NComp) as molweight(Brief="Molecular weight of components"); |
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| 373 | Ho(NComp) as enth_mol (Brief="Molar component enthalpy"); |
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| 374 | |
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| 375 | |
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| 376 | VARIABLES |
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| 377 | F as flow_mol (Brief="Molar Flow Rate"); |
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| 378 | Fmass as flow_mass(Brief="Mass flow rate", Symbol="F_{mass}"); |
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| 379 | z(NComp) as fraction (Brief="Molar Fraction"); |
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| 380 | zmass(NComp)as fraction (Brief="Mass fraction", Unit='kg/kg', Symbol="z_{mass}"); |
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| 381 | |
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| 382 | N(NComp) as positive (Brief="Mole fraction of component by initial biomass", Unit='kmol/kmol', Symbol="N_{mol}"); |
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| 383 | Nmass(NComp)as positive (Brief="Mass fraction of component by initial biomass", Unit='kmol/kmol', Symbol="N_{mass}"); |
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| 384 | |
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| 385 | Mws as molweight(Brief="Molecular weight of stream"); |
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| 386 | |
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| 387 | T as temperature(Brief="Temperature"); |
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| 388 | P as pressure (Brief="Pressure"); |
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| 389 | |
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| 390 | h as enth_mol (Brief="Molar stream enthalpy"); |
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| 391 | hmass as enth_mass(Brief="Mass stream enthalpy", Lower=-1e10, Upper=1e10, Symbol="h_{mass}"); |
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| 392 | E as enth_mol (Brief="Specific energy"); |
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| 393 | v as fraction (Brief="Vapourization fraction"); |
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| 394 | |
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| 395 | |
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| 396 | SET |
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| 397 | NComp = 8; # PP.NumberOfComponents; |
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| 398 | NElem = 5; # C,H,O,N,S |
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| 399 | |
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| 400 | # C H O N S |
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| 401 | na(:,1) = [0,2,1,0,0]; # H2O |
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| 402 | na(:,2) = [0,0,2,0,0]; # O2 |
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| 403 | na(:,3) = [0,0,0,2,0]; # N2 |
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| 404 | na(:,4) = [1,0,1,0,0]; # CO |
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| 405 | na(:,5) = [1,0,2,0,0]; # CO2 |
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| 406 | na(:,6) = [1,4,0,0,0]; # CH4 |
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| 407 | na(:,7) = [0,2,0,0,0]; # H2 |
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| 408 | na(:,8) = [0,0,2,0,1]; # SO2 |
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| 409 | |
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| 410 | Mw = PP.MolecularWeight(); |
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| 411 | Ho = PP.IdealGasEnthalpyOfFormationAt25C(); |
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| 412 | |
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| 413 | EQUATIONS |
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| 414 | "Mass stream enthalpy" |
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| 415 | hmass*Mws = h; |
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| 416 | |
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| 417 | "Mole fraction normalisation" |
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| 418 | sum(z) = 1; |
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| 419 | |
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| 420 | "Vapour stream" |
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| 421 | v = 1; |
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| 422 | end |
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| 423 | |
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| 424 | |
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| 425 | |
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| 426 | #*--------------------------------------------------------------------- |
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| 427 | * Model of a specific stream |
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| 428 | *--------------------------------------------------------------------*# |
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| 429 | Model stream_feed as stream_gasifier |
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| 430 | ATTRIBUTES |
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| 431 | Brief = "Model of a specific feed stream"; |
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| 432 | |
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| 433 | |
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| 434 | PARAMETERS |
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| 435 | To as temperature (Brief="Ambient temperature", Default=298); |
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| 436 | Po as pressure (Brief="Atmospheric pressure", Default=1); |
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| 437 | |
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| 438 | |
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| 439 | VARIABLES |
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| 440 | Fuel as raw_biomass (Brief="Raw biomass", Symbol="_{fuel}"); |
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| 441 | Air as air_stream (Brief="Air stream", Symbol="_{air}"); |
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| 442 | |
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| 443 | phi as Real (Brief="Equivalence ratio", Lower=0, Symbol="\phi"); |
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| 444 | Fw as Real (Brief="Mass air-fuel ratio", Lower=0); |
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| 445 | Fm as Real (Brief="Molar air-fuel ratio", Lower=0); |
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| 446 | |
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| 447 | |
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| 448 | EQUATIONS |
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| 449 | "Molar flow rate" |
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| 450 | F = Fuel.moisture.F + Air.F; |
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| 451 | |
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| 452 | "Mass stream feed flow rate" |
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| 453 | Fmass = Fuel.moisture.Fmass + Air.Fmass; |
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| 454 | |
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| 455 | |
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| 456 | "Molecular weight of stream" |
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| 457 | Mws*F = Fuel.moisture.F*Fuel.moisture.Mw + Air.F*Air.Mws; |
---|
| 458 | |
---|
| 459 | "Mass fraction" |
---|
| 460 | zmass*Mws = z*Mw; |
---|
| 461 | |
---|
| 462 | "Molar fraction by biomass" |
---|
| 463 | N*Fuel.dry.F = z*F; |
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| 464 | |
---|
| 465 | "Mass fraction by biomass" |
---|
| 466 | Nmass*Fuel.dry.Mw = N*Mw; |
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| 467 | |
---|
| 468 | |
---|
| 469 | "Molar stream enthalpy" |
---|
| 470 | h*F = Fuel.moisture.F*Fuel.moisture.H + Air.F*Air.h; |
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| 471 | |
---|
| 472 | #*--------------------------------------------------------------------- |
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| 473 | * C + O2 -> CO2 Hc(C) < 0 |
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| 474 | * H2 + O2 -> H2O Hc(H) < 0 |
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| 475 | * S + O2 -> SO2 Hc(S) < 0 |
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| 476 | * CO2 + H2O + N2 + SO2 -> CHNOS + O2 LHV > 0 |
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| 477 | * C + H2 + N2 + O2 + S -> CHNOS Hf = LHV + Hc(C+H+S) |
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| 478 | *--------------------------------------------------------------------*# |
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| 479 | "Biomass enthalpy" |
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| 480 | Fuel.dry.H = Fuel.dry.LHVmol |
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| 481 | + (Fuel.dry.na(1)*Ho(5) + 0.5*Fuel.dry.na(2)*Ho(1) |
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| 482 | + Fuel.dry.na(5)*Ho(8)); # CHONS CO2,H2O,SO2 |
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| 483 | # H2O, O2, N2, CO, CO2, CH4, H2, SO2 |
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| 484 | |
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| 485 | "Input energy" |
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| 486 | E = Fuel.dry.LHVmol; |
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| 487 | |
---|
| 488 | "Temperature" |
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| 489 | T = To; |
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| 490 | "Pressure" |
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| 491 | P = Po; |
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| 492 | |
---|
| 493 | |
---|
| 494 | # [H2O, O2, N2]/[Initial dry biomass] |
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| 495 | |
---|
| 496 | "Mass water fraction" |
---|
| 497 | Nmass(1) = Air.sh*Air.Fmass/Fuel.dry.Fmass + Fuel.moisture.massfrac; |
---|
| 498 | |
---|
| 499 | "Mass oxygen fraction" |
---|
| 500 | Nmass(2) = Air.zmass(2)*Air.Fmass/Fuel.dry.Fmass; |
---|
| 501 | |
---|
| 502 | "Molar fraction" # only O2,N2,H2O in the air |
---|
| 503 | Nmass(4:NComp) = 0; |
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| 504 | |
---|
| 505 | |
---|
| 506 | "Equivalence ratio" |
---|
| 507 | phi = N(2)/(1 + 0.25*Fuel.dry.na(2) - 0.5*Fuel.dry.na(3) + Fuel.dry.na(5)); |
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| 508 | |
---|
| 509 | "Equivalence rate of gasifying" # (Melgar,2007) |
---|
| 510 | Fm = Air.F/Fuel.dry.F; # molar base |
---|
| 511 | Fw = Air.Fmass/Fuel.dry.Fmass; # mass base |
---|
| 512 | end |
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| 513 | |
---|
| 514 | |
---|
| 515 | |
---|
| 516 | #*--------------------------------------------------------------------- |
---|
| 517 | * Model of a product stream |
---|
| 518 | *--------------------------------------------------------------------*# |
---|
| 519 | Model stream_products as stream_gasifier |
---|
| 520 | ATTRIBUTES |
---|
| 521 | Brief = "Model of a product stream"; |
---|
| 522 | |
---|
| 523 | |
---|
| 524 | PARAMETERS |
---|
| 525 | LHV_syngas(3) as enth_mass; |
---|
| 526 | |
---|
| 527 | |
---|
| 528 | VARIABLES |
---|
| 529 | Fvol as flow_vol (Brief="Volumetric flow rate (no solid)", Symbol="F_{vol}"); |
---|
| 530 | vm as volume_mol(Brief="Molar Volume"); |
---|
| 531 | z_db(NComp-1)as fraction (Brief="Molar fraction in dry base"); |
---|
| 532 | |
---|
| 533 | LHV as enth_mass(Brief="Mass low heat value", Upper=1e10, Symbol="LHV_{mass}"); |
---|
| 534 | |
---|
| 535 | |
---|
| 536 | SET |
---|
| 537 | LHV_syngas = [12.622,35.814,10.788]*'MJ/kg'; # CO,CH4,H2 |
---|
| 538 | |
---|
| 539 | |
---|
| 540 | EQUATIONS |
---|
| 541 | "Volumetric flow rate (no solid)" |
---|
| 542 | Fvol = F*vm; |
---|
| 543 | |
---|
| 544 | "Mass flow rate" |
---|
| 545 | Fmass = F*Mws; |
---|
| 546 | |
---|
| 547 | "Molar Volume" |
---|
| 548 | vm = PP.VapourVolume(T,P,z); |
---|
| 549 | |
---|
| 550 | "Molecular weight of stream" |
---|
| 551 | Mws = sum(z*Mw); |
---|
| 552 | |
---|
| 553 | "Mass fraction" |
---|
| 554 | zmass*Mws = z*Mw; |
---|
| 555 | |
---|
| 556 | "Mass fraction in dry base" |
---|
| 557 | z_db*(1 - z(1)) = z(2:NComp); |
---|
| 558 | |
---|
| 559 | |
---|
| 560 | "Low heat value of biomass syn-gas" |
---|
| 561 | LHV = (zmass(4)*LHV_syngas(1) + zmass(6)*LHV_syngas(2) |
---|
| 562 | + zmass(7)*LHV_syngas(3)); # /(zmass(4) + zmass(6) + zmass(7)); |
---|
| 563 | end |
---|
| 564 | |
---|
| 565 | |
---|
| 566 | |
---|
| 567 | ####################################################################### |
---|
| 568 | # MAIN MODEL |
---|
| 569 | ####################################################################### |
---|
| 570 | |
---|
| 571 | #*--------------------------------------------------------------------- |
---|
| 572 | * Equilibrium model of a biomass gasifier |
---|
| 573 | *--------------------------------------------------------------------*# |
---|
| 574 | Model gasifier |
---|
| 575 | ATTRIBUTES |
---|
| 576 | Info = " |
---|
| 577 | == Description == |
---|
| 578 | Thermodynamic equilibrium modeling of a biomass gasifier. |
---|
| 579 | |
---|
| 580 | == Assumptions == |
---|
| 581 | * thermodynamic equilibrium; |
---|
| 582 | * steady-state; |
---|
| 583 | * ideal gas relations; |
---|
| 584 | * ambient and atmospheric input conditions (To,Po); |
---|
| 585 | * global gasification reaction: |
---|
| 586 | CHONS + H2O + air -> CO + CO2 + CH4 + H2 + H2O + N2 + SO2 |
---|
| 587 | * no oxygen in the products. |
---|
| 588 | |
---|
| 589 | == Specify == |
---|
| 590 | * ultimate biomass analysis (dry.massfrac); |
---|
| 591 | * moisture biomass ratio (moisture.massfrac); |
---|
| 592 | * equivalence ratio (phi); |
---|
| 593 | * relative air humidity (air.rh); |
---|
| 594 | * equilibrium temperature (Teq). |
---|
| 595 | "; |
---|
| 596 | |
---|
| 597 | |
---|
| 598 | PARAMETERS |
---|
| 599 | PP as Plugin(Brief="External physical properties", |
---|
| 600 | Type="PP", |
---|
| 601 | Components = ["water","oxygen","nitrogen","carbon monoxide", |
---|
| 602 | "carbon dioxide","methane","hydrogen","sulfur dioxide"], |
---|
| 603 | LiquidModel = "IdealLiquid", |
---|
| 604 | VapourModel = "Ideal" |
---|
| 605 | ); |
---|
| 606 | |
---|
| 607 | NComp as Integer (Brief="Number of components", Default=8); |
---|
| 608 | NElem as Integer (Brief="Number of elements", Default=5); |
---|
| 609 | |
---|
| 610 | NReac as Integer (Brief="Number of reactions", Default=2); |
---|
| 611 | stoic(NComp,NReac) as Real (Brief="Stoichiometric matrix of considered reaction", Symbol="\nu"); |
---|
| 612 | Rg as Real (Brief="Universal gas constant", Unit='J/mol/K', Default=8.314); |
---|
| 613 | Po as Integer (Brief="Atmospheric pressure", Default=1); |
---|
| 614 | |
---|
| 615 | VARIABLES |
---|
| 616 | Inlet as stream_feed (Brief="Inlet stream", Symbol="^{in}", PosX=0.7165, PosY=0); |
---|
| 617 | Outlet as stream_products(Brief="Outlet stream", Symbol="^{out}", PosX=0.7165, PosY=1); |
---|
| 618 | |
---|
| 619 | K(NReac) as positive (Brief="Equilibrium constant", Lower=0); |
---|
| 620 | G(NComp) as enth_mol (Brief="Component Gibbs free energy"); |
---|
| 621 | Teq as temperature (Brief="Equilibrium temperature", Symbol="T_{eq}"); |
---|
| 622 | |
---|
| 623 | eff_cg as Real (Brief="Cold gas efficiency", Symbol="\eta_{cg}"); |
---|
| 624 | |
---|
| 625 | |
---|
| 626 | SET |
---|
| 627 | NComp = PP.NumberOfComponents; # 8 |
---|
| 628 | NElem = 5; # C,H,O,N,S |
---|
| 629 | #*--------------------------------------------------------------------- |
---|
| 630 | * Considered equilibrium reaction: |
---|
| 631 | * C + 2H2 <-> CH4 |
---|
| 632 | * CO + H2O <-> CO2 + H2 |
---|
| 633 | *--------------------------------------------------------------------*# |
---|
| 634 | NReac = 2; |
---|
| 635 | stoic(:,1) = [ 0, 0, 0, 0, 0, 1,-2, 0]; # C + 2H2 <-> CH4 |
---|
| 636 | stoic(:,2) = [-1, 0, 0,-1, 1, 0, 1, 0]; # CO + H2O <-> CO2 + H2 |
---|
| 637 | |
---|
| 638 | |
---|
| 639 | EQUATIONS |
---|
| 640 | for k in [1:NElem] |
---|
| 641 | "Material balance" |
---|
| 642 | Inlet.F*sum(Inlet.z*Inlet.na(k,:)) |
---|
| 643 | + Inlet.Fuel.dry.Fmass*Inlet.Fuel.dry.massfrac(k)/Inlet.Fuel.dry.Mw_(k) |
---|
| 644 | = Outlet.F*sum(Outlet.z*Outlet.na(k,:)); |
---|
| 645 | end |
---|
| 646 | |
---|
| 647 | |
---|
| 648 | "Fraction normalisation" |
---|
| 649 | sum(Outlet.z) = 1; |
---|
| 650 | |
---|
| 651 | |
---|
| 652 | "Heat balance" |
---|
| 653 | Inlet.F*(Inlet.z(1)*Inlet.Fuel.moisture.H + sum(Inlet.z(2:NComp)*Inlet.Ho(2:NComp))) |
---|
| 654 | + Inlet.Fuel.dry.F*Inlet.Fuel.dry.H = Outlet.F*Outlet.h; |
---|
| 655 | |
---|
| 656 | |
---|
| 657 | for j in [1:NReac] |
---|
| 658 | "Equilibrium constant" |
---|
| 659 | K(j) = prod(Outlet.z^stoic(:,j)); |
---|
| 660 | |
---|
| 661 | "Gibbs energy of reaction" |
---|
| 662 | sum(stoic(:,j)*G) = -Rg*Outlet.T*ln(K(j)); |
---|
| 663 | end |
---|
| 664 | |
---|
| 665 | |
---|
| 666 | "Gibbs energy of component" |
---|
| 667 | G = PP.IdealGasGibbsOfFormation(Outlet.T); |
---|
| 668 | |
---|
| 669 | Outlet.h = sum(PP.IdealGasEnthalpyOfFormationAt25C()*Outlet.z) |
---|
| 670 | + PP.VapourEnthalpy(Outlet.T,Outlet.P,Outlet.z); |
---|
| 671 | |
---|
| 672 | |
---|
| 673 | "Output energy" |
---|
| 674 | Outlet.E = Outlet.N(4)*(Inlet.Ho(4)-Inlet.Ho(5)) + Outlet.N(7)*(Inlet.Ho(7) |
---|
| 675 | -Inlet.Ho(1)) + Outlet.N(6)*(Inlet.Ho(6)-Inlet.Ho(5)-Inlet.Ho(1)); |
---|
| 676 | |
---|
| 677 | "Cold gas efficiency" |
---|
| 678 | eff_cg = Outlet.E/Inlet.E; |
---|
| 679 | |
---|
| 680 | |
---|
| 681 | # Outlet stream |
---|
| 682 | |
---|
| 683 | "Equilibrium temperature" |
---|
| 684 | Outlet.T = Teq; |
---|
| 685 | |
---|
| 686 | "Mechanical equilibrium" |
---|
| 687 | Outlet.P = Inlet.P; |
---|
| 688 | |
---|
| 689 | |
---|
| 690 | "Molar fraction by initial biomass" |
---|
| 691 | Outlet.N*Inlet.Fuel.dry.F = Outlet.z*Outlet.F; |
---|
| 692 | |
---|
| 693 | "Mass fraction by initial biomass" |
---|
| 694 | Outlet.Nmass*Inlet.Fuel.dry.Mw = Outlet.N*Outlet.Mw; |
---|
| 695 | end |
---|
| 696 | |
---|