#*------------------------------------------------------------------- * EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC. * * This LIBRARY is free software; you can distribute it and/or modify * it under the therms of the ALSOC FREE LICENSE as available at * http://www.enq.ufrgs.br/alsoc. * * EMSO Copyright (C) 2004 - 2007 ALSOC, original code * from http://www.rps.eng.br Copyright (C) 2002-2004. * All rights reserved. * * EMSO is distributed under the therms of the ALSOC LICENSE as * available at http://www.enq.ufrgs.br/alsoc. * *--------------------------------------------------------------------- * Spheric reactor *---------------------------------------------------------------------- * Solved problem from Fogler (1999) * Problem number: 4-8 * Page: 151 (Brazilian version, 2002) *---------------------------------------------------------------------- * * Description: * Sample to calculate of the molar conversion and pressure drop * as function of the length in a spheric reactor with a reaction of * dehydrogenation (reforming reaction): * paraffin -> oleffin + H2 * of first-order with respect to paraffin. * * Assumptions: * * change time in length * * steady-state * * isotermic system * * gaseous phase * * Specify: * * the inlet stream * * the kinetic parameters * * the parameters of reactor * * the parameters of catalyst packed bed * *---------------------------------------------------------------------- * Author: Christiano D. W. Guerra and Rodolfo Rodrigues * $Id: spheric_reactor.mso 574 2008-07-25 14:18:50Z rafael $ *--------------------------------------------------------------------*# using "types"; FlowSheet spheric_reactor PARAMETERS rho_0 as dens_mass (Brief="Initial density"); Dp as length (Brief="Particle diameter"); k_lin as Real (Brief="Specific rate of reaction", Unit='m^3/kg/s'); visc as viscosity (Brief="Flow viscosity"); L as length (Brief="Fixed bed half length"); rho_c as dens_mass (Brief="Catalyser density"); phi as fraction (Brief="Fixed bed porosity"); pi as Real (Brief="Number pi", Default=3.14159); R as length (Brief="Radius reactor"); VARIABLES X as fraction (Brief="Molar conversion"); y as Real (Brief="Dimensionless pressure drop (P/P0)", Lower=0); P as pressure (Brief="Output pressure", DisplayUnit='kPa'); z as length (Brief="Length of reactor"); beta0 as Real (Brief="Parameter beta0 of Ergun equation", Unit='Pa/m'); Ac as area (Brief="Tranversal section area", Lower=0); Ca0 as conc_mol (Brief="Input molar concentration of A"); Fa0 as flow_mol (Brief="Input molar flow of A"); P0 as pressure (Brief="Initial pressure", DisplayUnit='kPa'); m as flow_mass (Brief="Mass flow"); EQUATIONS "Change time in z" z = time*'m/s'; "Transversal section area" Ac = pi*(R^2 - (z - L)^2); "Parameter beta0 of Ergun equation" beta0 = m*(1 - phi)/(rho_0*Ac*Dp*(phi^3))*(150*(1 - phi)*visc/Dp - 1.75*m/Ac); "Molar conversion" diff(X) = k_lin*(Ca0*(1 - X)/(1 + X)*y)*rho_c*(1 - phi)*Ac/Fa0*'m/s'; "Pressure drop" diff(y) = -beta0/P0/y*(1 + X)*'m/s'; "Dimensionless pressure drop" y = P/P0; SET rho_0 = 32*'kg/m^3'; Dp = 0.002*'m'; k_lin = 2e-5*'m^3/kg/s'; visc = 1.5e-5*'kg/m/s'; L = 2.7*'m'; rho_c = 2600*'kg/m^3'; phi = 0.4; R = 3*'m'; SPECIFY Ca0 = 320*'mol/m^3'; Fa0 = 440*'mol/s'; P0 = 2000*'kPa'; m = 44*'kg/s'; INITIAL "Molar conversion" X = 0; "Dimensionless pressure drop" y = 1; OPTIONS TimeStep = 0.1; TimeEnd = 5.4; end