Absorber design in sour natural gas treatment plants: Impact of process variables on operation and economics = Absorberentwurf für Anlagen zur Behandlung von sauren Erdgasen: Einfluss Prozessparameter auf Betriebsführung und Prozesswirtschaftlichkeit

Two models of absorberhave been developed which describe the absorption of H2S and CO2 from natural gases by aqueous di-isopropanolamine (DIPA) or methyl-di- ethanolamine(MDEA) solutions. In these models mass transfer, reaction and equilibrium processes as they prevail in conventional tray absorbersand in cascades of trickle bed reactorsare incorporated. Owing to the better mass transfer characteristics of the latter type of absorber, i.e. the larger ratio between the gas phase and liquid phase mass transfer coefficients, kg/kl, higher selectivities for the absorption of H2S from sour natural gases are realized. The influence of variation of a number of operation and design parameters on tray absorberperformance, H2S selectivity and solvent flowrate is demonstrated. The economics of the above type of absorberstogether with a solvent regenerator, sulfur recovery unit and tail-gas unit are explained in detail. From the point of view of the economics tricklebed absorbersare very attractive owing to lower investment costs and higher selectivities, which result in lower operating costs than for tray absorbersunder identical conditions.