Risk Mitigation on Ammonia and Methanol Primary Steam Reformers using Retrofitted Safety Instrumented Systems: A Comparative Cost-benefit, Risk-informed Study
Primary steam reformers used in the “front end” of ammonia and methanol process plants are subject to severe property damage and extended production downtime in case of accidents initiated by abnormal deviations in certain process parameters. Safety instrumented systems can be installed on primary reformers to help reduce the frequency of such process upsets. After conducting a hazard analysis to identify the critical process parameters in a primary reformer, the appropriate level of reliability for instrumented safeguards should be determined using known risk ranking methods. A risk-informed cost-benefit analysis tool can then be deployed to compare alternative safety instrumentation systems, as demonstrated by an example in this paper.
KeywordsSteam Reformer International Electrotechnical Commission Safety Function Risk Ranking Critical Process Parameter
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- 1.Karydas, D., Mahnken, G. Safety analysis and system design of thermal oxidizers used for environmental protection from VOC emissions. In: Pasman, H.J., Fredholm, O., Jacobssen, A. (Ed) Proceedings of 10th International Symposium on Loss Prevention in the Process Industries, 19–21 June 2001, Stockholm Sweden, Elsevier Publishing, 2001, pages 545-559.Google Scholar
- 2.Kletz, Trevor A., HAZOP & HAZAN, Identifying and Assessing Process Industry Hazards, Institution of Chemical Engineers, Rugby U.K., 4th Edition, 1999.Google Scholar
- 3.IEC 61508: Functional Safety of Electrical / Electronic / Programmable Electronic Safety-Related Systems, International Electrotechnical Commission, Geneva, 1999.Google Scholar
- 4.ANSI/ISA S84.01-1996, Applications of Safety Instrumented Systems for the Process Industry, Instrument Society of America, Research Triangle Park, N. Carolina, USA, February 1996.Google Scholar
- 5.Risk reduction factor adapted from “A Practical Guide to Designing Safety Instrumented Systems”, Moore Products Automation, Publication BLQL-4, Rev. 1,1999.Google Scholar
- 6.“Crystal Ball 2000” software from Decisioneering, Inc. Denver, CO 80202 USA.Google Scholar