Utilization and results of hazard and operability studies in a petroleum refinery



The petroleum refining industry has been performing hazard analyses in process units to some extent since at least 1988 and in earnest since 1990, when the American Petroleum Institute published Recommended Practice No. 750, “Process Hazards Management.” The Hazard and Operability Study (HAZOPS) is the most widely used of the various analysis techniques available, in part because this highly structured technique is easy to teach and well-suited for continuous process units.

The results of HAZOPS fall into two broad categories, tangible and intangible. The tangible results are obvious: worksheets which detail event scanarios for potential process deviations, and action items, or recommendations for changes to process equipment of procedures. In many cases, the action items address issues which have a purely economic impact or which are procedural in nature, involving little or no capital investment.

The intangible results or products of a HAZOPS include: the training and knowledge gained by the team participants, and better utilization of limited capital funds resulting from more detailed up-front engineering when a HAZOPS is required prior to funding. An aggressive HAZOPS schedule also aids facilities in planning resources for process safety information updates where the necessary P&ID's or PFD's are out-of-date.

This paper details the experiences with HAZOPS at Chevron U.S.A. Products Company's Pascagoula, Mississippi Refinery. The manner in which HAZOPS are performed, the types of results obtained, and the benefits of the HAZOPS program will be discussed.