Abstract

Environmental issues such as global warming and economic considerations have resulted in the use of flare gas recovery systems to reduce flaring by capturing and either compressing the flare gases for other uses or recycling the flare gases to low-pressure process equipment.

Gasco requirement is to recover the flare gases of the three hydrocarbon flares instead of being continuously burnt. This should be through the installation of Flare Gas Recovery Systems (FGRS). This recovered gas should be either used as a fuel gas or injected back into the processing facilities.

World Bank has introduced the initiative "Zero Routine Flaring by 2030". In line with the above initiative, within Gasco there are KPIs which aim at reducing flaring and to recover the flared gases.

This is achieved through the successful implementation of Flare Gas Recovery Systems (FGRS) at GASCO Plants A, B and C.

Targeting Process Safety (PS), enhancement in HSE and performance monitoring, starting 2008, Gasco embarked on an ambitious Project requiring state of the art Flare gas recovery systems.

This Paper details the stages involved and detailed plan, i.e. Study, FEED and EPC. Optimization methodology necessary when designing or operating a reliable Flare Gas recovery Systems on existing Gas Plants to recover hydrocarbon gases over wide range of gas compositions without affecting the existing facilities.

A study was conducted on Hydrocarbon Flares of Gasco Plants A, B and C in order to predict the various continuous flow rates through the three Hydrocarbon Flare headers. It was predicted that for each of above plants the recovered gas could be in the order of ~1 to 2 MMscfd.

In FEED, considering the future additional flare gases, the design capacity of the individual flare gas recovery systems fixed at 5 MMscfd per train for each of above plants. EPC Package was developed to execute project on turnkey basis.

Proper FEED, EPC Detailed Design Review, HAZOP and SIL sessions produced an inherently safe Design.

In 2013 the project was successfully commissioned. The FGR system was found capable of operating at flowrates up to the design flowrate across the full range of molecular weights.

Actual recovery of Flare Gas post implementation on a yearly average basis for a period of three years (2013/2014/2015) are reproduced below:

  • Plant A - 1.40 / 1.75 / 2.17 MMscfd

  • Plant B - 1.58 / 1.78 / 1.86 MMscfd

  • Plant C - 1.36 / 1.65 / 1.81 MMscfd

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