A Novel Low-Cost Process for Sour Gas Sweetening and NGL Recovery

Abstract

Greater than 40% of global natural gas reserves are sour, with hydrogen sulfide concentrations that make processing that gas uneconomic in most cases. Furthermore, it is desirable to economically sequester acid gas contaminants from these resources due to growing environmental concerns. Current conventional technologies such as amine, cryogenic, and membrane systems typically fail to achieve the aforementioned objectives. Thus, there is a need to develop new technologies for sour gas processing. In this work, a new low temperature process for sweetening and fractionation of highly-sour natural gas is presented. The process, called "TarT", is capable of separating CO2 and H2S contaminants from the sales gas as high-purity, high-pressure streams while also recovering the NGL content of the feed gas. It is shown that the TarT process consumes about 37% less energy as compared to conventional MDEA sweetening and NGL recovery processes to produce sales gas, C4, C4+ NGL blend and high-pressure CO2 and H2S contaminant streams. The TarT process introduces a new and highly economically advantaged approach to fractionate highly-sour natural gas and sequester the resulting acidic gases.