The Maloperation Risk Identification Based On Digraph Models Of Batch Process

Alone with the increasingly maximization and complication, various fatal accidents continue to occur, and the world paid a heavy price. How to protect the safety of the process industry becomes an important direction of scientific research worldwide. Chemical process is divided into continuous process and batch process. Because the batch processes are widely used in food, polymers, pharmaceuticals, dyes and other products, therefore it is received widely attention. For batch process with lower automatic, they require many manual operations. These manual operations make the possibility of maloperation occurring increase. Therefore, it is necessary to analyze effects of maloperation on batch process so that protective measures can be effectively taken.This paper proposes a new modeling method using digraph models. The established model is divided into lower part and upper part based on Petri net and signed directed graph (SDG). It is added the model elements such as operation node, control place and judging module and so on. The concept of relation variable, target variables checklist, operation nodes checklist and relation variables checklist is firstly proposed combining the characteristics of batch process. Finally, three types of maloperation including earlier or later, error opening or error closing and adding steps or deleting steps, are used to validate the model.The result shows that the model can solve the problem of previous method which cannot describe the specific operation. And the model structure is simple and integrated. In this method, the maloperation is described conveniently, and risk identification is conducted effectively aiming at maloperation.