Entropy Generation Analysis of a Thermal Cracking Reactor

The present paper analyzes the entropy generation of a tabular thermal cracking reactor with propane feed, as well as the molecular mechanism of the reaction. The reaction model is obtained and the flow, reaction, momentum, and energy are determined with knowledge of the outer wall temperature. Then, the equations of entropy generation in the tabular reactor are solved and the rate of entropy generated by three sources along the reactor is determined. After that, the temperature of the tube or reactor is changed using the reference results, and the results and procedures are replicated. The results obtained for two states show that the three factors are in the order of chemical reactions, heat transfer, and pressure loss in terms of their contribution to entropy generation. The decrease in input feed temperature does not influence the weight percent of the products considerably, but when the wall temperature is reduced, as is the case with the optimal wall temperature state, the conversion percent in the reactor is reduced. The entropy generated by heat transfer in reactors with lower feed temperature is much higher at the beginning of the reaction. These variations do not affect the pressure-induced entropy considerably. The variation of input feed temperature does not affect the entropy generated by the chemical reactions, but the entropy produced in the reactor with optimal wall temperature is the lowest. At the inlet of the reactor, the entropy is higher when the wall has optimal temperature, which can be attributed to its higher rate of reactions than the other two states of input feed temperature.