Multistage Operation with Cold-Shot Cooling
Consider three packed-bed catalytic reactors (PBCRs) in series and an exothermic reversible reaction A ⇄ B. To overcome conversion limitations due to chemical equilibrium, the three reactors in series are used with cold-shot cooling (i.e., cold fresh feed is mixed into the reactors' effluents at the entrances of reactors two and three).[more]
This Demonstration computes the conversion versus temperature graph, which exhibits the conversion improvement due to this particular setup. These reactors have sizes selected such that the exit conversion from each one of them is equal to 95% of the equilibrium conversion.
A flow diagram shows the reactor setup (R1, R2, and R3) as well as the two heat exchangers (C and H) used in this process (one for cooling purposes at the exit of the process and the other for heating the stream at the entrance of the first reactor). The sum of the values of the split ratios r1, r2, and r3 must be equal to one. In the present Demonstration, their values are equal to 0.2, 0.4, and 0.4, respectively.[less]
R. W. Missen, C. A. Mims, and B. A. Saville, Introduction to Chemical Reaction Engineering and Kinetics, New York: Wiley, 1999.