Text of the GNU GPL.
%% Copyright (C) 2001, James B. Rawlings and John G. Ekerdt %% %% This program is free software; you can redistribute it and/or %% modify it under the terms of the GNU General Public License as %% published by the Free Software Foundation; either version 2, or (at %% your option) any later version. %% %% This program is distributed in the hope that it will be useful, but %% WITHOUT ANY WARRANTY; without even the implied warranty of %% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU %% General Public License for more details. %% %% You should have received a copy of the GNU General Public License %% along with this program; see the file COPYING. If not, write to %% the Free Software Foundation, 59 Temple Place - Suite 330, Boston, %% MA 02111-1307, USA. global E km Tm Gamma beta Rg Pf Nf Ta Ac Tf %% %% o-xylene + 3 O_2 --> phthalic anhydride + 3 H_2O %% %% %% parameters adapted from Welsenaere and Froment, 1970. %% %% %% jbr, 9/21/01 %% repaired by jbr, 1/2/10 %% %% units: m, kg, kmol, sec %% R = 1.25e-2; %tube radius, m Ac = pi*R*R; % tube cross-section, m^2 Qrho = 0.0026371; % Ac*4684/3600 mass flow, kg/sec, constant Pf = 1.01e2; % feed pressure, kN/m^2, i.e. 1.0 atm Mwf = 0.98*(0.79*28+0.21*32)+0.02*106.17; % mol wt feed; % 98%air, 2% o-xylene, kg/kmol Tf = 625; % feed temperature, K Rg = 8.314; % gas constant, kJ/(K kmol) %Nf = Qrho*Mwf; bug here; repaired below; adjust km and delH as well Nf = Qrho/Mwf; % molar flowrate, kmol/sec, also constant E = 13636.; % activation energy, K Tm = 625.; % mean temperature, K %km = 1922.6; % 1/sec % adjusted on 1/2/10 km = 2.0822; % 1/sec Ta = 625; % coolant temperature, K Cp = 0.992; % specific heat of mixture, kJ/kg K, assumed constant %delH = -1.361e3; % kJ/kmol % adjusted on 1/2/10 delH = -1.284e6; % -3.07e5*4.184 heat of reaction, kJ/kmol, assumed constant U = 0.373; % heat transfer coefficient, kJ/(m^2 sec K) beta = delH*Ac/(Qrho*Cp); % heat of reaction parameter, Gamma = 2*pi*R*U/(Qrho*Cp); % heat transfer parameter, l = 1.5; % length of tube, m npts = 200; z = linspace(0,l,npts)'; yxfeed = [0.019]; Nxf = yxfeed*Nf; %Tfeed = [615 625 631 635]; % adjust the temperatures in the repaired file Tfeed = [615 620 625 630]; nfeed = length(Tfeed); yx = zeros(npts,nfeed); T = zeros(npts,nfeed); for i = 1: nfeed Tf = Tfeed(i); x0 = [Nxf; Tf]; opts = odeset ('AbsTol', sqrt (eps), 'RelTol', sqrt (eps)); [tsolver, x] = ode15s (@pfr, z, x0,opts); yx(:,i) = x(:,1); T(:,i) = x(:,2); end table = [z yx T]; subplot(2,1,1); plot (z, yx); title ('Figure 6.36') subplot(2,1,2); plot (z, T); title ('Figure 6.36')
function rhs = pfr(t, x) global E km Tm Gamma beta Rg Pf Nf Ta Ac Tf Nx = x(1); T = x(2); Q = Nf/(Pf/(Rg*T)); cx = Nx/Q; k = km*exp(-E*(1/T-1/Tm)); rate = k*cx; rhs = [-rate*Ac; -beta*rate + Gamma*(Ta-T)];