Optimized treating configurations for the combined removal of H H2S, CO S, CO2 and mercaptans from Natural Gas for LNG and GTL applications

摘要

A number of large LNG and GTL projects will be launched in the coming years. These projects are often based on feed gas containing H H2S, CO S, CO2 and organic sulphur components, such as mercaptans and carbonyl sulphide. Their respective treating units will require full removal of the sulphur components, plus total or partial removal of CO CO2. Traditionally, the preferred acid component removal routes were based on various amine-based or mixed solvent processes for relevant sulphur component removal, followed with drying of the gas by molecular sieves. Alternatively, amine processes have been selected which did not remove the mercaptans, the latter being achieved by the molecular sieves or a physical solvent processes. This paper presents an optimised line-up for the removal of H H2S, CO S, CO2 and organic sulphur components. Sulfinol, a mixed solvent, removes a portion of the mercaptans. The remaining mercaptans are removed in a downstream molecular sieve unit and are then captured from regeneration gas processed by the Sulfinol unit, consolidated in to the acid gas stream. This process combination is optimised against operational and capital expenditure. Other treating options like acid gas enrichment absorption, acid gas re-injection and SRU tail gas treatment can be supported by this process line-up.