Selecting Technologies for Sour and Ultra-Sour Gas Treating

As the cleanest fossil fuel, natural gas plays a key role in the path towards renewables. Considering the increasing gas demand, rich CO₂ and H₂S gas reserves, in the past considered economically unviable, are becoming fruitful. However, the non-conventional nature of this kind of gases, in addition to the potentially higher production cost, raises the need of new strategies for their monetization, bypassing the conventional approaches. Starting from the huge number of novel large-scale projects for the exploitation of rich-H₂S gas fields, this paper overviews the current tendencies in sour and ultra-sour natural gas production, focusing on the removal of sulfur-based compounds, together with H₂S and CO₂. At first, available technologies for ultra-sour gas treatment are discussed. Then, simulations of the absorption processes based on a real case-study are carried out, in order to verify the effectiveness of the proposed alternatives for the removal of mercaptans, as well as CO₂ and H₂S. Results are critically analyzed, in view of providing a practical guide of industrial interest for the selection of the most suitable method.