Crude Stabilization Process Description

Crude Stabilization Process Description

Pressurized Crude Oil coming out from BUT and HUT oil trunk lines into five streams and preheated by steam up to 45^oC before entering into High Pressure Separators operating at pressure of 3.5 kg/cm²g. The oil flows out under level control and can either be directed towards low pressure separator or can be pumped to the Dehydrator system. High pressure gas letup the HP separators under pressure control and is sent for compression.

If, the oil contains water and/or salt it can be dehydrated in the Dehydrator systems. Before entering the Dehydrators, oil is preheated first by heat exchange with dehydrated oil and then in the crude heaters up to 65°C.

The Dehydrators operate at 2.5 Kg/cm²g and at 65°C. The dehydration is accomplished by injection of demulsifies, heating and application of high voltage electro-static field in the oil-water emulsion. The gas liberated in the Degasser of the dehydrator flows under pressure control to the compressors. 

The dehydrated oil, which came from dehydrator system, flows under level control, exchange heat with feed to dehydrator and is then sent Low Pressure Separators. The produced water flows under interface level control and is sent to the Waste Treatment Plant or EPTP (Effluent Pretreatment Plant) for predisposal treatment.

Series operation of dehydrators A and B is also available. The Low Pressure Separators operate at 0.1 Kg/cm²g and 50/55°C. The oil pumped to HSVR cooler flows under level control into the two Intermediate Surge Tanks by gravity where final separation of gas is achieved.

The stabilized oil is pumped to five Main Storage Tanks. From these tanks oil is pumped into the trunk line dispatch oil to the Trombay Terminal for onward distribution to BPCL Refinery, HPCL storage or (Butcher Island Jetty) Jawahar Deep Island.

The gases from HP separators, Degassers and LP Separators are compressed in the Multi service Gas Compressors and sent to LPG unit combining with associated gas from the trunk line. These are 3 stages reciprocating 

Compressors, operating at suction pressures of0.05 Kg/cm²g, 3.0 Kg/cm²g and 14.0 Kg/cm²g respectively with a final discharge pressure of 51.0 Kg/cm²g. The Degassers and LP separator gases are connected to compressor 1st and HP separator gases are connected to 2nd stage suction.