Resolving Catalytic Soot and Coke Formations Challenges in a Liquefied Natural Gas Plant: Operational Experiences

In an extremely competitive Oil and Gas industry, heat and energy optimisation is a crucial design consideration in plant designs to ensure optimum business performance. One common approach is via the employment of Waste Heat Recovery Unit (WHRU) at the flue gas path of gas turbines. Incompatible WHRU materials and process conditions could potentially lead to conducive environment that promotes unexpected catalytic soot and coke formations that results in severe equipment fouling and integrity concerns, which in turn could adversely impact sustainable plant production. With understanding of factors that promotes conducive environment for catalytic soot and coke formations, these can be avoided and sufficient designs considerations can be made from Project phase in ensuring long term plant availability and utilization.

PETRONAS Liquefied Natural Gas (LNG) Complex; nestled in a small town of Bintulu, in the coastline of Sarawak, Malaysia, consists of three LNG Plants operated as one integrated site. The three plants namely Malaysia LNG (MLNG), Malaysia LNG Dua (MLNG DUA) and Malaysia LNG Tiga (MLNG TIGA) with total LNG deliverable capacity of about 23 million tonnes per annum (mtpa). The first plant, MLNG with three modules (Modules 1, 2 and 3) began operation in 1983. This was followed by the second plant, MLNG DUA, which started its operations in 1994 also with three modules (Modules 4, 5 and 6). The third plant, MLNG TIGA with two modules (Modules 7 and 8) was later integrated with the existing site and came into operations in 2003.

This paper enlightens the accomplishment of the implementation of a redesign of the Regeneration Gas Heater (RGH) in the WHRU in MLNG TIGA to fully resolve catalytic soot and coke formations. Most importantly, this paper shares the lessons learnt from the Root Cause Analysis (RCA) study and the mitigations actions carried out in order to manage the tremendous operational challenges faced by MLNG TIGA team to maximise plant availability, all while working for the long term implementation of the RGH redesign.