//Harriot P.,2003,Chemical Reactor Design (I-Edition) Marcel Dekker,Inc.,USA,pp 436. //Chapter-7 Ex7.7.a Pg No.304 //Title:Apparent value of kLa and regime of operation //====================================================================================================================== clear clc //INPUT Vol_reactor=35;//Volume of reactor(L) No_reactor=3;//No. of reactor T_C=155;//Operating Temperature (°C) T_ref=273;//Reference Temperature (°C) T_K= T_C+T_ref;//Operating Temperature (K) P=8.2;//Operating Pressure (atm) X_conversion=9.5*10^(-2);//Conversion S=73*10^(-2);//Selectivity M_cyclohexane=84.16;//Molecular weight of cyclohexane F_cyclohexane=100;//Feed rate of cyclohexane (L/hr) F_air=9.9;//Feed rate of air (nm3/hr) f_O2_air=0.21;//Fraction of O2 in air V_ref=22400;//Reference volume at STP(cm3/mol) y_O2=0.002;//O2 in vent gas f_O2_consumed=0.99;//Fraction of O2 Consumed rho_cyclohexane=0.779;//Density of cyclohexane at 20 (°C) main_pdt_ratio=3/2; by_pdt_ratio=(1-main_pdt_ratio); stoi_rxn_O2=[0.5 1]; rho_M=0.650;//Density of Cyclohexane at 155 (°C) P_dash=5.8;//Vapour Pressure of cyclohexane at 155 (°C) D_reactor=30;//Diameter of reactor (cm) h_reactor=50;//Height of reactor (cm) myu_20=0.98;//(cp) Viscosity at 20(°C) myu_155=0.2// (cp) Viscosity at 155(°C) //CALCULATION F_O2=(F_air*10^(6)*f_O2_air)/(3600*V_ref); delta_N_O2=F_O2*f_O2_consumed; F_C6=(F_cyclohexane*10^(3)*rho_cyclohexane)/(3600*M_cyclohexane) F_prdts=F_C6*X_conversion*S; F_O2_prdts=F_prdts*(main_pdt_ratio*stoi_rxn_O2(1)+by_pdt_ratio*stoi_rxn_O2(2)); F_O2_remain_used=delta_N_O2-F_O2_prdts; F_O2_prdts_conver=F_O2_prdts/(F_C6*X_conversion*S); F_O2_remain_used_conver=F_O2_remain_used/(F_C6*X_conversion*(1-S)); X_O2=10^(0.366*log10(T_K)-3.8385);//O2 solubility from Wild et al. [37]: PO2_plus_PN2=P-P_dash; P_O2=y_O2*PO2_plus_PN2; x_O2=P_O2*X_O2;//Mol fraction of O2 C_M=rho_M*10^(3)/M_cyclohexane; C_O2_star=C_M*x_O2; //Assume each reactor has 30 L solution V_soln_n=30;//Volume of solution in each reactor apparent_kLa=(delta_N_O2)/(V_soln_n*No_reactor*C_O2_star); F_total=(F_air*10^(6)/3600)*(T_K/T_ref)*(8.2/2.4)*(1/8.2);//The total vapor flow is 8.2/2.4 times the air flow CSA_reactor=%pi*(D_reactor^2)/4; u_g=F_total/(CSA_reactor*No_reactor); //Calculation for predicted value of kLa kLa_20=0.16;//From Figure 7.16, for O2–C6H12 at 20 (°C), 2 cm/sec, 5 kW/m3 T_data=20+T_ref;//Temperature at which data is taken from the table D_155_by_D_20=(T_K/T_data)*(myu_20/myu_155); Predicted_kLa=kLa_20*(D_155_by_D_20^(0.5))*(u_g/2)^(0.5); //OUTPUT mprintf('\nThe value of apparent kLa: %0.1f (sec-1)',apparent_kLa); mprintf('\n The value of predicted kLa: %0.2f (sec-1)',Predicted_kLa); if (apparent_kLa>Predicted_kLa) mprintf('\nThe absorption of oxygen is greatly enhanced by chemical reactions in the liquid film') mprintf('\nThe kinetics can be approximated by a first-order expression,the reaction would fall in the pseudo-first-order regime,\nwhere the rate varies with the square root of the oxygen diffusivity and the rate constant.') end fid= mopen('.\Chapter7_Ex7_a_Output.txt','w'); mfprintf(fid,'\nThe value of apparent kLa: %0.1f (sec-1)',apparent_kLa); mfprintf(fid,'\n The value of predicted kLa: %0.2f (sec-1)',Predicted_kLa); if (apparent_kLa>Predicted_kLa) mfprintf(fid,'\nThe absorption of oxygen is greatly enhanced by chemical reactions in the liquid film') mfprintf(fid,'\nThe kinetics can be approximated by a first-order expression,the reaction would fall in the pseudo-first-order regime,\nwhere the rate varies with the square root of the oxygen diffusivity and the rate constant.') end mclose('all'); //==========================================================END OF PROGRAM===============================================