An inherently safer design approach for thermal runaway risk control of plug flow reactors based on process safety time

Abstract

The reaction system is the core of the chemical process system. Thermal runaway risk control of the chemical reaction process is the fundamental prerequisite for the safe, stable, long-term and optimal operation of the process system. Therefore, this work proposed an inherently safer multi-objective optimization approach for plug flow chemical reactors, which took maximum target product yield as the economic objective and minimum Dow’s fire and explosion index as the safety objective. To achieve this goal, a mathematical model was built for process representation and was formulated as a nonlinear programming problem solved through the deterministic algorithm. The process safety time was introduced as the critical criterion for the control of thermal runaway risk risen by unexpected failure. Finally, two illustrative examples were conducted to demonstrate the feasibility and effectiveness of the proposed method. The results indicated that the obtained optimal schemes of this work could significantly improve the product yield, reaction efficiency and inherent safety performance of the reaction system by 20%, 16% and 3%, respectively, compared with that of the conventional temperature threshold criterion widely applied in practical.