A modified inherent thermal runaway hazard index (m-ITHI) for risk assessment of chemical processes based on cloud model

Microreactors have been applied in chemical processes to prevent thermal runaway. However, the assessment method comparing thermal runaway hazards of chemical processes in microreactors and stirred-tank reactors is hardly reported. Therefore, in order to evaluate and compare the comprehensive thermal runaway hazard of chemical processes using stirred-tank reactors and microreactors under the unified evaluation index system, a modified inherent thermal runaway hazard index (m-ITHI) was proposed. Damage radius (DR), which was a function of process inventory and reaction heat, was introduced to characterize the thermal runaway severity of materials and reactions. Moreover, cloud model theory was applied to deal with the fuzziness and randomness of thermal runaway hazard indicators. The method was illustrated by processes in microreactors and stirred-tank reactors. Then, it was compared with Quantitative Index of Inherently Safer Design (QI2SD) and inherent thermal runaway hazard index (ITHI). Overall, m-ITHI can provide a way to compare thermal runaway hazard of chemical processes in different scale reactors.