Failure analysis of LNG centrifugal pump and its solutions

Author of the article:BAI Yuheng1, DENG Dongfeng2, ZHANG Qichao3, MA Shaofeng1, LIU Zhuchen4

Author's Workplace：1. CPECC Southwest Company, Chengdu, Sichuan, 610041, China; 2. China Petroleum Engineering & Construction Corporation, Beijing, 100120, China; 3. Gas Transmission Management Office, PetroChina Southwest Oil & Gasfield Company, Chongqing, 102649, China; 4. PetroChina Planning & Engineering Institute, Beijing, 100083, China

Key Words：LNG centrifugal pump; Cavitation analysis; Rectification plan

Abstract：In one LNG liquefaction plant, the difficulties in pre-cooling and starting LNG centrifugal pump, and abnormal operation were analyzed by means of on-site observation, data collection and theoretical analysis and calculation. The results show that there are high flow resistance in the pump pre-cooling process system; vapour lock in the piping in front of the pump; and the pump cavitation is the main reason for abnormal operation. According to the analysis results, the rectification plan is given in accordance with the field situation. The operation of LNG centrifugal pump is obviously improved after the rectification. Finally, it is suggested that the process flow and piping layout of LNG centrifugal pump be designed to reduce the piping resistance of the pre-cooling system and the change of medium temperature be considered in the calculation of the cavitation allowance of LNG centrifugal pump. The pipeline before the pump should avoid the formation of “air pockets”.