This paper describes the operator’s zero-cost solutions to reduce greenhouse gas (GHG) emissions by 30% from the total permeate stream, power generation, and purchased electricity; and to add more than $20 million of revenue annually through monetization of recovered hydrocarbon from permeate streams in the acid-gas-removal unit (AGRU) at one of its natural gas terminals in Malaysia.
Introduction
Offshore upstream natural-gas suppliers transport their production to multiple onshore receiving terminals, where it is treated and blended to meet required specifications, particularly the maximum CO2 mol% at the gas-processing-plant (GPP) delivery point. In one of the natural-gas supply chains, where the CO2 concentration exceeds GPP requirements, the gas is processed at a terminal equipped with a membrane-based AGRU system, which is designed to reduce CO2 concentration in sales gas.
AGRU Design
Feed gas from offshore upstream suppliers is first directed to the pretreatment unit. The AGRU is equipped for two stages of gas processing with its primary and secondary membranes. The treated, on-spec gas leaving the primary membrane is compressed by the sales-gas compressor (SGC) before being exported to the GPP. The byproduct stream from the primary membrane, known as the permeate, which still contains a high concentration of valuable hydrocarbons, is then sent to the secondary membrane by a booster-gas compressor (BGC) for further hydrocarbon recovery (Fig.
