Optimal design of an auto-thermal ammonia synthesis reactor

In the present study, the Differential Evolution (DE), an evolutionary computation technique, is applied to the optimal design of an auto-thermal ammonia synthesis reactor. This paper also presents the new concept of “Nested DE” (DE is also used to find out the best combination of key parameters of DE itself). The main objective in the optimal design of an autothermal ammonia synthesis reactor is the estimation of the optimal length of reactor for different top temperatures with the constraints of energy and mass balance of reaction and feed gas temperature & mass flow rate of nitrogen for ammonia production. Thousands of combinations of feed gas temperature, nitrogen mass flow rate, reacting gas temperature and reactor length are possible. This paper presents the application of two methods, viz., Runge-Kutta variable step size method, and Gear’s method in combination with DE, and verify the contradictory results reported using simple GA in earlier literature. Apart from determining the optimal reactor length, the comparison of results obtained from different methods is presented. DE is found to be a robust, fast and simple evolutionary computation technique for optimization problems.