Chemical Engineering - Industrial Organic Chemistry

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Andrea Landella POLITECNICO DI MILANO Industrial Organic Chemistry Exam Jan 17, 201 8 Consider a double stage adiabatic reactor , with intermediate cooling , for methanol production : The inlet to R -101 is a mixture of H 2/CO/CH 4 at 190°C and 100 atm , with H 2/CO = 3.75 and CH 4/CO = 0.25. The heat exchanger E -101 is ideal, with unitary efficiency. The second reactor R-102 is at equilibrium, while R-101 has a CO conversion of 35% , and the overall CO conversion is 50%. Assuming ideal mixture of perfect gases, with negligible Poynting correction and negligible pressure drops, i t is required to evaluate : The minimum number of required chemical reactions in the reactor: The degree of advance of the first reactor λ1 and the outlet composition y1 ; The temperature at the outlet of R -101, or T1; The temperature at the outlet of E -101, or T2, and the heat exchanged Q ; The degree of advance of the second reactor λ2, and the outlet temperature T3; R-101 R-102 Equilibrium E-101 F1,y1,T1 F0,y0,T0 F2,y2,T2 F3,y3,T3 Q Andrea Landella POLITECNICO DI MILANO DATA: The available data are the equilibrium constant of the methanol synthesis, all the temperatures are in Kelvin: The reference state for calculation of the activities is the perfect gas at 1 atm. Heat capacities vary with temperature , and are expressed as follows : the molar enthalpies of formation in the reference state are listed for eac h reactive specie in the following table, together with the Heat capacity constants: Specie Δfh0(298 K) [cal/mol ] A B×10 3 C×10 5 D×10 8 E×10 11 CO -26405,617 3.912 -3.913 1.182 -1.302 0.5155 H2 0 2.883 3.681 -0.772 0.692 -0.213 CH 4 -17802,828 4.568 -8.975 3.631 -3.407 1.091 CH 3OH -48004,566 4.714 -6.986 4.211 -4.443 1.535 2 5 2 9 3 12 4 9.8585ln 1.0362 10 1.5137 10 7.4889 10 1 ( ) 25722.614 exp 1.987 1.4359 10 18376.875 / 3.5356 eq T T T T KT TT − − − −  − −  +  −  =   +  + −    2 3 4 () Cp T A BT CT DT ET R = + + + +