Compressor Surge Analysis Case Study

Problem

A petrochemical plant had experienced two major failures of a centrifugal compressor during start-up. The plant was concerned that the modification of the control system caused the compressor to surge during the start-up process. The plant hired KHE to determine the cause of the surge and to make recommendations for successful startup of the compressor.

Solution

An integrated surge model was developed for the compression system including two compressor cases, intercoolers, suction and discharge piping as well as the dump valve used to prevent surge during start-up.

Results

The surge analysis identified that, under certain start-up conditions, the 1st compression stage was likely to surge. In addition, review of the start-up practice identified several drain valves and an additional vents that, if open during a throttled start, would increase the likelihood of surge. Recommendations were made which resulted in a successful startup.