A design framework for optimized economic and inherently safe operation conditions for isoperibolic semi-batch reactors

Abstract

Thermal runaway in the semi-batch reactors (SBRs) involving exothermic reaction can have serious consequences and the primary driver of process design in the SBRs is economic performance. Hence, in this article, a general framework for safe-economic design and operation of isoperibolic SBRs via integrating advanced process optimization and inherently safe operation condition identification criteria is proposed, and is applied to homogeneous solution polymerization. First, a criterion is proposed to identify the thermally safe operation condition (QFS region, quick onset, fair conversion, and smooth temperature) of homogeneous solution polymerization and the comparison with the other common criteria is conducted. The adiabatic temperature diagrams are also extended to homogeneous solution polymerization considering avoiding triggering side or decomposition reactions under cooling failure. Furthermore, a large accumulation can occur due to the rapid decomposition of the initiator when the jacket temperature in the QFS region exceed a threshold value. Therefore, a new temperature diagram is introduced via combination initiator decomposition temperature and adiabatic temperature diagrams. Finally, the optimal safety-economic design of the simulation case is conducted. The process optimization algorithm is genetic algorithm and runaway criteria are the proposed criterion in this article and the target temperature criterion. The comparison between the target criterion and proposed criterion shows there are almost approximately identical conversion profiles and temperature profiles. This result proves the general proposed framework and further proves the validity of the proposed criterion. This general framework can be extended to other kinetic schemes and this work can contribute to the inherent safety design of semi-batch reactors.