Comprehensive risk assessment for the esterification processes based on Dempster-Shafer evidence theory and cloud model

As a typical chemical process, esterification is usually exothermic and has a high risk of fire and explosion. To recognize and control the risk, it is vital to conduct risk assessment. Therefore, a comprehensive risk assessment method for the esterification process was proposed in this study. By analyzing the characteristics and hazards of the esterification process, a comprehensive evaluation index system was established. It covers four aspects including risk of materials, risk of reaction, possibility of thermal runaway inhibition and risk of process conditions. The improved Dempster-Shafer evidence theory integrates the Hellinger distance and the Pignistic vector angle. It effectively deals with the conflicts between different experts when determining weights. And the cloud model was used to grade index criteria, converting qualitative and quantitative assessment results. This was done to deal with the randomness and ambiguity in the assessment process. Syntheses of butl acetate and tert-butyl peroxyacetate were adopted as case study to validate the proposed method. The assessment results are generally consistent with the Dow's Fire and Explosion Index (F&EI) and the Inherent Benign⁃ness Indicator (IBI). This work will provide a new method for comprehensive risk assessment of the esterification process and can be further used for process optimization.