(5b) New Concept of on-Line Wash for Centrifugal Compressor

This paper introduces the development of new concept of on-line wash oil injection system which includes the optimization of quantity of washing oil, location of injection nozzles, direction of nozzle entry, hole size as well as control system.

The process gas compressor is the most critical unit in an ethylene plant and several types of contaminates can often foul the compressor flow path, causing deterioration in performance and significant losses in plant production. In order to prevent the efficiency losses due to fouling during long term operation, wash oil is injected as regular intervals/ continuously in process gas compressors. As common practice, wash oil injection nozzle are usually installed on the suction piping as well as return bend on each stage. Foulant material has been reported during turn around (and with few years of operation) even though wash oil injection has been carried out at required intervals.

User and OEM investigated the root cause of this phenomenon and constructed the new concept design of on-line wash oil injection system in consideration of wash area, oil quantity, erosion and feasibility of machine construction etc. by means of FEM (Finite Element Method) analysis as well as CFD (Computational fluid dynamics). To verify the effectiveness of this new concept of oil injection system, component test and actual machine verification test was conducted and successfully completed under User’s witness.

After completion of the test, OEM delivered newly developed oil injection system in user site that the fouling materials on the compressors were reported with conventional oil injection system, and commercial operation was started. User and OEM confirmed the effectiveness of newly developed system at site process gas compressor by checking the compressor performance.