clear ; clc; // Example 26.5 printf('Example 26.5\n\n'); //page no. 819 // Solution // Given CA = 10000 ;// Produced citric acid - [kg] f_glucose = .30 ;// Fraction of glucose in solution con_glucose = .60 ;// Fraction of glucose consumed w_glucose = 180.16 ;// Mol. wt. of d,alpha glucose -[g] H_glucose = -1266 ;// Specific enthalpy change of glucose - [kJ/g mol] w_CA = 192.12; // Mol. wt. of citric acid -[g] H_CA = -1544.8 ;// Specific enthalpy change of citric acid - [kJ/g mol] w_BM = 28.6 ;// Mol. wt. of biomass -[g] H_BM = -91.4 ;// Specific enthalpy change of biomass - [kJ/g mol] H_CO2 = -393.51 ;// Specific enthalpy change of CO2 - [kJ/g mol] // Main reaction is : // 3 * glucose + 7.8*O2 ---> 5.35*BM + 2.22*CA + 4.50*CO2 ..reaction (a) // Material Balance mol_CA = CA/w_CA ;// Mole of citric acid produced - [kg mol] g_soln = (mol_CA*(3/2.22)*w_glucose*1)/(con_glucose*f_glucose) ;//Mass of 30 % glucose solution introduced -[kg] i_glucose = g_soln* f_glucose / w_glucose ;// Initial moles of glucose - [kg mol] f_glucose = (1 - con_glucose)*i_glucose ;// Final moles of glucose - [kg mol] f_CA = mol_CA ;// Final moles of citric acid - [kg mol] f_BM = f_CA*(5.35/2.22) ;// Using the reaction (a)- Final moles of biomass - [kg mol] i_O2 = i_glucose*(7.8/3) ;// Using the reaction (a)- Initial moles of O2 - [kg mol] f_CO2 = i_glucose*(4.5/3)*con_glucose ;// Using the reaction (a) - Final moles of CO2 - [kg mol] // Energy balance // For closed system - del_U = Q + W power = 100 ;// Power of aerator -[hp] time = 220 ;// Time taken for reaction - [ hr ] W = (power*745.7*time*3600)/1000 ;// Work done by aerator - [kJ] // Assume del_U = del_H , pv work is equal to zero ,hence // Q = del_H - W Hi_glucose = i_glucose*H_glucose*1000 ;// Enthalpy change of glucose input - [kJ] Hi_O2 = i_O2*0*1000 ;// Enthalpy change of O2 input - [kJ] H_in = Hi_glucose + Hi_O2 ;// Enthalpy change of input - [kJ] Hf_glucose = f_glucose*H_glucose*1000 ;// Enthalpy change of glucose output - [kJ] Hf_BM = f_BM * H_BM*1000 ;//Enthalpy change of biomass output - [kJ] Hf_CA = f_CA *H_CA*1000 ;//Enthalpy change of citric acid output - [kJ] Hf_CO2 = f_CO2 *H_CO2*1000 ;//Enthalpy change of CO2 output - [kJ] H_out = Hf_glucose + Hf_BM +Hf_CA + Hf_CO2 ;// Enthalpy change of output - [kJ] del_H = H_out - H_in ;// Total enthalpy change in process - [kJ] Q = del_H - W ;// Heat removed - [kJ] printf('Heat exchange from the fermentor during production of 10,000 kg citric acid is %.2e kJ(minus sign indicates heat is removed).\n',Q) ;