Dispersion Modelling Assessment For Positioning Of Hydrocarbon Vapour Detection System, ONGC Hazira

Oil and Natural Gas Corporation Ltd. Of India has set up a gas processing plant at Hazira in Gujarat. The Hazira Plant is located at KAWAS adjacent to KRIBHCO fertilizer plant. The Plant is designed to process 20 MMNM3/day of gas and associated condensate (in Phase-I & II). The gas and associated condensate are received at the Plant from the Offshore platforms in Bombay High/ South Bassein Oil/Gas fields through a sub-sea pipeline.

After commissioning of Phase-III & IIIA, total design capacity has increased to 38.5 MMNM3/Day of gas (one GSU train standby concept) & associated condensate. Hazira Plant consists of Gas/ Condensate Terminal facility, Gas Sweetening, Gas Dehydration, Condensate Fractionation, Condensate Stabilisation (presently not being used), Dew Point Depression, Kerosene Recovery, and Sulphur Recovery Units & LPG Recovery Plant. Sterling & Wilson has awarded iFluids Engineering to carry out Fire and Gas Mapping Study for ONGC Hazira plant.

The Fire and Gas Mapping Study has been carried out based on OISD standards. Probable failure and leak scenarios in LPG Unit were identified and dispersion of flammable Hydrocarbon (HC) gas leaks in different leak orientation and wind directions were analyzed. The optimum location and mounting height of the Fire and Gas detectors are identified based on the flammable gas footprints evaluated by the simulation software.

The objectives of the F & G Gas Mapping study for LPG unit of ONGC Hazira are:

  • Identifying all potential hazards that will lead to flammable gas release or ignition.
  • Determination of the characteristics of the likely gas release by modelling the physical effect and consequently quantifying the extent of hazardous scenario on the project facilities.
  • Proposing new fire and gas detection arrangements.