Integrated Cryogenic HSE Index for Early Risk Screening of Gas Liquefaction and Petrochemical Cold Sections

Gas liquefaction, petrochemical refrigeration, and oil and gas processing units include several hazards that can occur at the same time, such as flammable gas release, cryogenic exposure, thermal stress on equipment, and delayed isolation. Conventional hazard studies usually treat these risks separately, although in real plants a small leakage in a cold section can quickly become more serious when detection, drainage, ventilation, and emergency isolation are not well balanced. This study proposes an Integrated Cryogenic HSE Index, called ICHI, for early risk screening of cold sections in gas liquefaction and petrochemical processes. A representative liquefaction section was divided into five process nodes, including feed gas compression, mixed refrigerant compression, cold box inlet, LNG rundown, and pump seal area. The index combines likelihood, consequence severity, personnel exposure, cryogenic thermal stress, detection reliability, and isolation effectiveness. A baseline case and a modified safety case were compared. The results showed that the cold box inlet had the highest baseline index, with an ICHI value of ۶۳.۰, mainly because of high cryogenic severity, equipment crowding, and limited direct access during operation. After applying practical safety modifications, including improved detector placement, faster isolation, insulation inspection, and better drainage control, the index of this node decreased to ۴۲.۷. The overall results indicate that a combined HSE index can support early decision making before detailed quantitative risk assessment is performed. The proposed method is simple enough for screening studies, but it should be supported by plant data, dispersion modeling, and reliability analysis before final design decisions.

کلیدواژه ها:

process safety ، gas liquefaction ، cryogenic leakage ، petrochemical HSE ، risk index