clear; clc; // Illustration 5.1 // Page: 114 printf('Illustration 5.1 - Page: 114\n\n'); // solution //***Data***// // a = NH3, b = H2O d = 2.54*10^(-2);// [m] Yag = 0.80; Xal = 0.05; T = 273+26.7;// [K] Kl = 2.87*10^(-5);// [kmol/square m.s.(kmol/cubic m)] Sh = 40; Da = 2.297*10^(-5);// [square m.s] P = 1.0133*10^(5);// [N/square m] Xbm = 1.0; //*********// Ma = 18;// [kg/kmol] // Liquid: // Because of large conc. of ammonia in gas F's rather than k's are used. // Molecular weight of water and ammonia are nearly same. // The density of the solution is practically that of water. MolarDensity1 = 1000/Ma;// [kmol/cubic m] // Kl is determined for dilute soln. where Xbm is practically 1.0 Fl = Kl*Xbm*MolarDensity1;// [kmol/square m.s] Ma = 18;// [kg-/kmol] // Gas: MolarDensity2 = (1/22.41)*(273/(273+26.7));// [kmol/cubic m] Fg = Sh*MolarDensity2*Da/d;// [kmol/square m.s] // Mass Transfer Flux // Th eqb. distribuion data for NH3 from "The Chemical Engineers Handbook" 5th Edt. p3-68: // Data = [Xa,pa] // Xa = NH3 mole fraction in gas phas // pa = NH3 partial pressure in N/square m Data = [0 0;0.05 7171;0.10 13652;0.25 59917;0.30 93220]; // Ya_star = mole fraction of NH3 in gas phase at eqb. Ya_star = zeros(5); for i = 1:5 Ya_star(i) = (Data(i,2)/P); end // For transfer of only one component Na_by_SummationN = 1.0; Ya = zeros(5); for i = 1:5 Ya(i) = 1-((1-Yag)*(1-Xal)/(1-Data(i))); end scf(0); plot(Data(:,1),Ya_star,Data(:,1),Ya); xgrid(); xlabel('Xa = mole fraction of NH3 in liquid phase'); ylabel('Ya = mole fraction of NH3 in gas phase'); legend('equilibrium line','operating line'); title('Ya Vs Xa'); // From intersection of operating line & Eqb. line Xai = 0.274; Yai = 0.732; // From Eqn.5.20 Na = Na_by_SummationN*Fg*log((Na_by_SummationN-Yai)/(Na_by_SummationN-Yag));// [kmol NH3 absorbed/square m.s] printf("Local mass transfer flux for ammonia is %e kmol/square m.s",Na);