Risk Based Inspection (RBI) Applied to Power Boilers - Successful Case in Brunei

Editor's Note: This article is summarized from information on the public record, on the Internet. More detailed information may be found at the URL: http://www.irl.cri.nz/home/innovinmar00.htm#Riskbasedinspectionkeepsplantsteeming. Or, visit the Industrial Research Limited website at http://www.irl.cri.nz/

This is a summary about RBI application to plant utility boilers in a liquefied natural gas plant with a design life of 20 years, now 27 years old. The plant is the Brunei Liquefied Natural Gas plant, which began operating in 1972. It is owned jointly by the government of His Majesty the Sultan and Yan Di Pertuan of Brunei Darussalam, the Mitsubishi Corporation of Japan, and the Royal Dutch Shell Group, with Shell also being the technical adviser.

Plant production capacity is 7.2 million tonnes of LNG per year. Product is shipped to customers in Japan and Korea. According to the website article the plant has not missed making a shipment of LNG in 27 years. It is crucial that reliabity/ availability levels remain high. To ensure it continues to operate reliably, the plant recently commissioned a remnant life assessment of its nine steam- generating boilers.

The plant’s utility boilers are central to the whole operation as they generate steam for the production process and electricity for the plant. No steam means no production.

To undertake the life assessment, one of the boilers was examined during a routine shutdown to assess both its current condition and the potential for degradation, and to identify the components most at risk. Because the nine boilers are identical in design, age and operating regimes, the results from one boiler could be applied across all nine. Inspection records covering the plant’s 27 year life were used as references, in addition.

Although a remnant life assessment had been carried out 10 years earlier, rules and methods of assessment had changed and become more sophisticated. Study participants needed to know the exact condition of the boilers for accurate future predictions and wanted to get a better feel for any refurbishment needed or any large capital expenditures for advanced planning. The resulting report gave them the assurances they needed about reliability of the boilers and a Risk Based Inspection plan to further optimize ongoing inspection and maintenance. Study participants believe RBI focuses inspection on those things which matter the most for safety and are critical to the production process. This means not wasting time and money inspecting areas, which don’t need to be assessed.

RBI differs from conventional inspection regimes that generally prescribe regular time intervals between inspections. Many times RBI reduces the frequency of examinations required, while providing a consistent and auditable approach.

RBI has come into focus worldwide through new international standards and its increasing acceptance by regulators. Many companies, such as Shell, are implementing RBI methods at plants, world wide, including Brunei LNG.