Abstract: Aiming at assessing inherent safety of chemical process scientifically,a cloud model was built,in which the pressure,temperature,inventory,explosiveness,flammability,toxicity and reactivity were chosen as the evaluation factors.The chemical process parameters and the grading standards were transformed into normal cloud grading standards.The comprehensive weights of factors were obtained via the entropy weight method.In order to determine inherent safety level of each process route and the corresponding inherent safety level,a maximum membership principle of fuzzy subset B was developed.As a case study,four process routes of MMA were analyzed with the above model,the results indicated no obvious difference from the results of Prototype Index for Inherent Safety,Inherent Safety Index,i-Safe.It shows that the model can determine the level of chemical inherent safety assessment accurately and provide a sound basis for the process route selection.

Key words: chemical process, inherent safety, cloud model, entropy weight method, safety assessment