Abstract: Blower steam turbine and induced draft fan steam turbine are important equipment of the 2500t/d methanol plant of certain company. The main oil pump installed at the shaft end of the steam turbine is a three-screw pump. During the operation of the two main oil pumps, the main safety valves of the main body have taken off frequently to varying degrees. By studying and troubleshooting the failure phenomenon, the problem was identified. According to the failure characteristics of the two main oil pumps, effective measures were taken involving redeploying the amount of oil in the main oil pumps of the blower and adjusting the opening of the self-regulating valve. For the induced draft fan, the equipment fault was eliminated through changing the speed ratio of the gear box of oil pumps to reduce the speed of oil pumps. The above-mentioned experience can provide reference for relevant technical personnel to deal with similar faults.

Key words: steam turbine, screw oil pump, safety valve, frequent take-off, gear box