GRA and AHP Analysis of Pneumatic Control Valve Failure in an LNG Plant

To analyse the causes of pneumatic valve failures in liquefied natural gas (LNG) plants, sort out the occurrence rules of failures and accurately perform failure prediction and spare parts inventory in engineering, this paper takes the damage frequency of key components of the pneumatic control valve, valve usage and instrument wind of the Kunlun Energy Hubei LNG plant from 2014 to 2019 as data samples. The Grey relational analysis model and analytic hierarchy process model are selected to perform unsupervised mathematical experiments. The results show that the faults of the pneumatic control valve can be decomposed into explicit faults, implicit faults and indirect faults. In engineering, attention should be paid to the sufficient inventory of key components of solenoid valves and positioners, and timely treatment should be administered when faults are found. In addition, targeted inspections should be regularly performed to reduce the frequency of dominant faults. At the same time, attention should be paid to the degree of damage caused by indirect faults, and regular monitoring of the water content and cleanliness of instruments should be conducted. The data of this mathematical experiment are well-coupled, and the accuracy of the model is controllable. However, the experiment shows that the basic data remain discrete. The next step should be to strengthen the data collection work, at the same time broaden the boundary of fault performance factors, and introduce data, such as the influence degree of the pneumatic control valve fault on the subordinate equipment, local process system, overall process system and its energy consumption. Standard analysis should be conducted in the process industry.