Unconventional Waste & Flare Gas Recovery System UFGRS in New Circular Economy

Abstract

Keeping pace with the rest of the world on reducing the greenhouse gas emission, Saudi Aramco embarked on an aggressive program to minimize or cut routine flaring and energy resources used in producing oil and gas through policies, standards and inhouse innovations. The innovative Unconventional Waste & Flare Gas Recovery System UFGRS has supported the corporate strategy to minimize or eliminate routine flaring with minimum CAPEX and OPEX. This paper present in detail the innovative Ejector Based Unconventional Waste/Flare Gas Recovery System (UFGRS) without using gas compressors. The objective of the project is to eliminate the hydrocarbon gas release to atmosphere for any upset flameout scenario from GOSP-A massive flare & relief system and continuously recover 1.825 Billion Standard Cubic Feet per year (1.825 BSCFY) of valuable purge gas with the lowest CAPEX and OPEX. Conventional Flare Gas Recovery System (FGRS) using gas compressors is the normal choice deployed in many facilities to recover the routine gas flaring but it was found to have high CAPEX and OPEX (maintenance, high power consumption & labor intensive) compared to the value of the recovered gas. Also, the compressors based FGRS is more complex and less reliable than the ejector (static) based FGRS. In addition, the innovative FGRS is capable of handling high turndown ratios compared to convention compressor based FGRS. Also, additional innovative parts of this idea is the integration with the existing compression system and the use of only static equipment like ejectors, pipes, valves and water seal drums to recover the waste/flare gas. The idea has very low operating cost compared to conventional flare gas recovery systems, apart from significant gas savings. The unconventional FGRS system was proven successfully in December 2020. The system is currently in operation for 8 months without any interruption and managed to eliminate the total design routine gas flaring rate of 1.825 BSCFY GOSP-A producing facilities. Also, the project resulted in reducing CO2 emission by 106,000 ton/year which positively contributed to the kingdom circular economy initiatives. To further enhance the ejector based FGRS, a US Patent No. 10,429,067 was granted in October 2019 to utilize the Ejector based FGRS concept for Emergency flare gas recovery. The innovative idea includes utilizing multiple ejectors in parallel with provision of different ejectors operating at different pressures that will allow the system to be used to recover flare gas over a range of different flow rates corresponding to different emergency release scenarios. Also, two new patents are under filing to utilize the liquid as motive fluid instead of the gas.