Considerations for Flare Gas Recovery Design in Khangiran Gas Treating Plant

摘要

Khangiran Gas Treating Plant designed by American Davy PowerGas Inc in 1977, was to flare all flashing gases before 2011 that was guessed to be 1 percent of its NG production. Environmental and economical concerns led to plan a conceptual design project on its recovery. Because of the high extent of CO2, the flare gas flow rate could not be measured via conventional monitoring methods- for example ultra-sonic. Beside successful efforts on measurement that led to reliable methods and also a novel measuring apparatus, a comprehensive design was raised to achieve a near zero-flaring condition. The plan consists of three main steps: 1- establishing a 5 barg header to collect and use H2S-free and enough-pressure streams as a supplementary fuel gas, 2-establishing a 6.5 barg header and an amine tower to collect and refine sour and enough-pressure streams and then, adding to the 5 barg header, 3- compressing the remained low-pressure streams from the seal-pot to the 6.5 barg header. These steps will cause to achieve 50, 25 and 25 percent of the final recovery goal, respectively and to reduce 167000 tons/year CO2 emission. Currently, the first step has been completed and the basic and detailed design of the second step has been carried out by consultant.