Introduction to Chemical Engineering Institute of Process Engineering 1.2 Previous exam question: CSTR with first order reaction Consider the following liquid-phase first-order irreversible reaction (e.g, a decomposition reaction) A+B+C Its rate of reaction is r=ke (r in mol L-15-1), where c (mol L- is the concentration of the reactant A, and k (sl) is the reaction rate constant (the reaction rate constant is a function of temperature, whose value doubles when the temperature increases from 40C to 70C). The reaction is carried out in a CSTR (Continuous Stirred Tank Reactor) of volume V L), which is kept at the desired operating temperature. The system is operated at steady state, with an inlet and outlet volumetric flow rate Q L s "). a) Please, write the material balance equation that describes the behavior of the system, by defining the proper inlet and outlet conditions. b) Please, write the outlet concentration, c, as a function of the inlet concentration, Cin, and of the other parameters characterizing the system and its operation. c) Consider ca = 10 mol/L, V=100 L and Q=10 L/s, and an operating temperature T= 40C where k = 0.1 s 1. Please, calculate the outlet concentration, c, under these conditions. d) Assume that production has to be doubled, i.e. Q becomes 20 L/s. Under the constraint that the outlet concentration must remain the same as calculated at point c), what can one do to cope with this new production demand without building a second production line and a second reactor? More specifically, how can one change the operating conditions in the CSTR so as to treat 20 L/s and attain the same outlet concentration, c