DETERMINATION OF THE OPTIMAL TEMPERATURE-TIME POLICY FOR PACKED BED REACTORS USING DEACTIVATING CATALYSTS

Abstract

For reactors with deactivating catalyst the operating policy must change with time. The choice of a policy which will maximize the profit from the process over the life of the catalyst is very important. Temperature is often the most important process variable. The selection of operating temperature-time policy can be posed as a problem suitable to the use of dynamic programming but for complicated catalytic operations such as industrial reforming, its application is limited due to excessive machine memory requirement. An alternative methodology, namely the use of calculus of variations and Fontryagin's maximum principle is proposed and justified with examples in the present work. The reformer optimization is very complicated due to multiple reaction, adiabatic operation, bifunnctional catalyst, number of reactors involved etc. It is, therefore, considered advisable to develop the use of the technique starting with simple situations then successively extend it to incorporate complex realities of the reforming operation. Optimization of isothermal reactor for single irreversible reaction and adiabatic rseCtOrs for single irreversible and reversible as well as multi-ple reversible reaction has been discussed in the present work. It has been assumed that the readtion does not involve any change in the number of moles. The catalyst has been assumed to be menofunntional. The software has been .developed and optimal policies evaluated. Extension of the effort to reformer optimization using the proposed optimization methodology appears to be possible.