| 1 | #*------------------------------------------------------------------- |
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| 2 | * EMSO Model Library (EML) Copyright (C) 2004 - 2007 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 - 2007 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 | * Spheric reactor |
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| 17 | *---------------------------------------------------------------------- |
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| 18 | * Solved problem from Fogler (1999) |
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| 19 | * Problem number: 4-8 |
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| 20 | * Page: 151 (Brazilian version, 2002) |
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| 21 | *---------------------------------------------------------------------- |
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| 22 | * |
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| 23 | * Description: |
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| 24 | * Sample to calculate of the molar conversion and pressure drop |
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| 25 | * as function of the length in a spheric reactor with a reaction of |
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| 26 | * dehydrogenation (reforming reaction): |
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| 27 | * paraffin -> oleffin + H2 |
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| 28 | * of first-order with respect to paraffin. |
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| 29 | * |
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| 30 | * Assumptions: |
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| 31 | * * change time in length |
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| 32 | * * steady-state |
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| 33 | * * isotermic system |
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| 34 | * * gaseous phase |
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| 35 | * |
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| 36 | * Specify: |
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| 37 | * * the inlet stream |
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| 38 | * * the kinetic parameters |
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| 39 | * * the parameters of reactor |
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| 40 | * * the parameters of catalyst packed bed |
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| 41 | * |
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| 42 | *---------------------------------------------------------------------- |
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| 43 | * Author: Christiano D. W. Guerra and Rodolfo Rodrigues |
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| 44 | * $Id: spheric_reactor.mso 574 2008-07-25 14:18:50Z rafael $ |
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| 45 | *--------------------------------------------------------------------*# |
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| 46 | |
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| 47 | using "types"; |
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| 48 | |
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| 49 | |
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| 50 | FlowSheet spheric_reactor |
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| 51 | PARAMETERS |
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| 52 | rho_0 as dens_mass (Brief="Initial density"); |
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| 53 | Dp as length (Brief="Particle diameter"); |
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| 54 | k_lin as Real (Brief="Specific rate of reaction", Unit='m^3/kg/s'); |
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| 55 | visc as viscosity (Brief="Flow viscosity"); |
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| 56 | L as length (Brief="Fixed bed half length"); |
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| 57 | rho_c as dens_mass (Brief="Catalyser density"); |
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| 58 | phi as fraction (Brief="Fixed bed porosity"); |
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| 59 | pi as Real (Brief="Number pi", Default=3.14159); |
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| 60 | R as length (Brief="Radius reactor"); |
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| 61 | |
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| 62 | VARIABLES |
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| 63 | X as fraction (Brief="Molar conversion"); |
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| 64 | y as Real (Brief="Dimensionless pressure drop (P/P0)", Lower=0); |
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| 65 | P as pressure (Brief="Output pressure", DisplayUnit='kPa'); |
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| 66 | z as length (Brief="Length of reactor"); |
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| 67 | beta0 as Real (Brief="Parameter beta0 of Ergun equation", Unit='Pa/m'); |
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| 68 | Ac as area (Brief="Tranversal section area", Lower=0); |
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| 69 | Ca0 as conc_mol (Brief="Input molar concentration of A"); |
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| 70 | Fa0 as flow_mol (Brief="Input molar flow of A"); |
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| 71 | P0 as pressure (Brief="Initial pressure", DisplayUnit='kPa'); |
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| 72 | m as flow_mass (Brief="Mass flow"); |
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| 73 | |
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| 74 | EQUATIONS |
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| 75 | "Change time in z" |
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| 76 | z = time*'m/s'; |
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| 77 | |
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| 78 | "Transversal section area" |
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| 79 | Ac = pi*(R^2 - (z - L)^2); |
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| 80 | |
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| 81 | "Parameter beta0 of Ergun equation" |
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| 82 | beta0 = m*(1 - phi)/(rho_0*Ac*Dp*(phi^3))*(150*(1 - phi)*visc/Dp - 1.75*m/Ac); |
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| 83 | |
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| 84 | |
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| 85 | "Molar conversion" |
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| 86 | diff(X) = k_lin*(Ca0*(1 - X)/(1 + X)*y)*rho_c*(1 - phi)*Ac/Fa0*'m/s'; |
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| 87 | |
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| 88 | "Pressure drop" |
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| 89 | diff(y) = -beta0/P0/y*(1 + X)*'m/s'; |
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| 90 | |
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| 91 | "Dimensionless pressure drop" |
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| 92 | y = P/P0; |
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| 93 | |
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| 94 | SET |
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| 95 | rho_0 = 32*'kg/m^3'; |
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| 96 | Dp = 0.002*'m'; |
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| 97 | k_lin = 2e-5*'m^3/kg/s'; |
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| 98 | visc = 1.5e-5*'kg/m/s'; |
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| 99 | L = 2.7*'m'; |
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| 100 | rho_c = 2600*'kg/m^3'; |
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| 101 | phi = 0.4; |
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| 102 | R = 3*'m'; |
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| 103 | |
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| 104 | SPECIFY |
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| 105 | Ca0 = 320*'mol/m^3'; |
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| 106 | Fa0 = 440*'mol/s'; |
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| 107 | P0 = 2000*'kPa'; |
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| 108 | m = 44*'kg/s'; |
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| 109 | |
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| 110 | INITIAL |
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| 111 | "Molar conversion" |
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| 112 | X = 0; |
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| 113 | "Dimensionless pressure drop" |
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| 114 | y = 1; |
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| 115 | |
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| 116 | OPTIONS |
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| 117 | TimeStep = 0.1; |
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| 118 | TimeEnd = 5.4; |
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| 119 | end |
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