Abstract: In April 2018, high level alarms frequently went off in the fifth-stage suction tank of cracking gas compressor in the ethylene plant in Tianjin. Since this happened after the installation of the fourth-stage discharge cooler (EA207B), technical personnel checked the level gauge of the fifth-stage suction tank, the process parameters, and the pressure difference in cooler (EA207/EA207B). It was concluded that the serious coking and blockage in EA207 made the outlet pipe of EA207 a liquid storage pipe, thus resulting in the high level alarms. By adding a technical transformation pipeline, the water and hydrocarbons accumulated in the outlet pipe of EA207 were discharged to quench tower, successfully solving the problem, eliminating the potential safety hazards in production and ensuring the stable operation of the ethylene plant.

Key words: cracking gas compressor, level of fifth-stage suction tank, cause analysis of alarm