Development of Anti-Surge Controls and Protection System for Motor Driven CO2 Compressors in DCS at KRIBHCO

摘要

The plant of Krishak Bharati Co-Operative Limited(KRIBHCO)was commissioned in 1986 at Hazira(Surat)consists of two streams of ammonia(each of 1890 MTPD capacity)and four streams of urea(each of 1662.5 MTPD capacity).Four streams of urea plants are having steam turbine driven CO2 compressors.In 2020,two new motor driven CO2 compressors were installed in two streams of urea plants at KRIBHCO as energy saving measure.Steam turbine driven CO2 compressors for these two streams are now used as standby.New CO2 compressor is centrifugal type compressor driven by the main electric motor through speed increasing gear.The casing consists of multi-stage impellers.Process gas passes through a suction strainer and enters the compressor.The gas is compressed up to the specified pressure in this compressor.This article describes the design philosophy and successful implementation of anti-surge controls and protection system for motor driven CO2 compressor in plant DCS.