Study On Risk Evaluation Method Of Compressor System Of Compressor Station

Pressurization system is the core part of the gas compressor station, which responsible for the important task of pressurizing natural gas for the entire pipeline system, therefore, the safe operation of the pressurization system directly related to the ensurance of natural gas transsmission to downstream with required quality, quantity and time. So far, there isn’t a system risk assessment for pressurization system in of the gas compressor station in domestic and foreign. So it is of great significant to carry out research on risk assessment method for the pressurization system in order to guarantee the safe operation of the pressurization system in the gas compressor station.As the pressurization system has complex structure, each part of the system always has some relation to another, but precious studies up to now mostly biased in favor of a single issue or device, which didn’t take into account of the influence between various parts. So it is necessary to study the entire pressurization system as a whole.This paper proposed to use influence diagram theory to curry out the pressurization system risk assessment, and set the pressurization system composed of gas turbine and centrifugal as research object. At first, according to different funtions, the system was divided into7subsystems, which include centrifugal compressor body, gas turbine body, lubrication system, air system, dry gas seal system, control system, fuel gas system. Second, based on the identified risk factors of each system, established the influence diagram of each subsystem and the entire pressurization system, at the same time, established risk assessment index system of the pressurization system, and according to the inference algorithm of the probability influence diagram, the failure likelihood value could be acquired. Considering the other factors had influence to the system, another influence diagram including human factors, management factors, environmental factors, design factors has also been established, and from which the contribution of each factor to the failure of pressurization system was acquired. Then, comprehensively considering the consequences from pressurization system failure, such as death, direct economic losses and intangible losses, and use the attribute comprehensive evaluation model to calculate the comprehensive consequence severity of pressurization system failure. Finally, according the risk acceptable criteria, combined with the pressurization system actual operation requirement, the risk matrix was drawn. And the method was applied to the Nanchang gas compressor station, the result from which was consistent with the actual operation, which verified the rationality of the method.In this risk assessment method, probability influence diagram was introduced in to considering the relationship of each subsystem, the failure likelihood of the entire sytem acquired from this method was higher than the value considering each subsystem separately. This was consistent with the actual situation.