Integrity of LNG Flare Systems

Abstract

Abstract ADGAS is a leading LNG producer. It is the pioneer LNG supplier in the region. LNG trains are operated since 1977. Through those years of experience, ADGAS has been following a stringent Asset Integrity Management System for all its plants. Among these plants are the flare and relief systems. Flare systems are considered safety critical. Maintaining the integrity of these systems is a challenge. This paper shares ADGAS best practices in maintaining the asset integrity of these plants. The paper also highlights the latest development in the area of flare systems inspection and shares same case histories. The world of Asset Integrity Management has advanced over the few decades to a great deal. Inspection has progressed from being time based to condition based then to being Risk Based. ADGAS Asset Integrity Management has passed through all these developments. For instance inspection of flare systems and plants was first time based. Then based on the performance of some of its plant systems it became condition based. Afterwards more optimization was added and it became Risk based. Technology has also advanced across the years, for instance, flare tips replacement was a strictly time based program. Then became condition based, then now we can inspect the flare tips systems online using special Unmanned Aerial vehicles (UAV's). This enabled ADGAS to truly optimize on maintenance and replacements of the flare tips. These examples will be shared in the paper. Furthermore at few instances failure of some flare systems provided great experience to avoid recurrence, flashback case, flare piping systems ageing and repair are all cases that are to be shared in the presentation. Utilization of latest inspection technology, latest repair technology and monitoring enabled ADGAS to optimise its inspection and maintenance costs. The last savings on flare systems maintenance were estimated at a value of USD MM 3.5. Some old flow control measures were proven to possible create problems, for example restriction orifices to control the flow of purge gas can get blocked if not maintained. Restriction orifices can be changed for other means of control to avoid possible restriction of purge gas flow which is essential for the integrity of flare systems. Latest UAV inspection technology has added towards the inspection and maintenance of flare systems. Utilization of more advanced monitoring and flow control of flare purge gases is of high importance. Usage of novel techniques in piping repair represented an important aspect in optimizing the maintenance cost of flare systems.