Application: Removal of hydrogen sulfide (H2S), COS, RSH, other organic sulfur compounds and bulk or deep removal of carbon dioxide (CO2) from natural, synthetic and refinery gases. Total sulfur compounds in the treated gas can be reduced to ultra-low ppm levels, as required for refinery-fuel and pipeline quality gases.
An improved application is to selectively remove H2S, COS, RSH and other organic sulfur compounds for pipeline specification, while co-absorbing only part of the CO2. Deep CO2 removal for LNG plants is another application, as well as bulk CO2 removal with flash regeneration of the solvent. The process sequence Sulfinol/Claus/SCOT—can be used advantageously with an integrated Sulfinol system that handles selective H2S removal upstream and the SCOT process that treats the Claus offgas.
The mixed solvent consists of a chemical reacting alkanolamine, water and physical solvent Sulfolane (tetra-hydrothiophene dioxide). The actual chemical formulation is customized for each application. Unlike aqueous amine processes, Sulfinol removes COS, RSH and other organic sulfur compounds to stringent total sulfur specifications. The process achieves 4 ppm H2S pipeline specification at low stream consumption. Observed corrosion rates are low and very little foaming is experienced, both are controlled through the application of optimized design.
The system line-up resembles that of other amine processes. In most applications, co-absorbed hydrocarbons from the absorber (1) are flashed (2) from the solvent and used as fuel gas after treatment in a fuelgas absorber (3). Loaded solvent is regenerated (4).
Operating conditions: Very wide ranges of treating pressures and contaminant concentrations can be accommodated. Refinery-fuel gas and gas pipeline specifications, such as 40 ppmv total sulfur and 100 ppmv H2S, are readily met. Removal of organic sulfur compounds is usually done for the circulation set by H2S and CO2 removal. In LNG plants, a 50 ppmv CO2 specification is easily attained.
Licensor: Shell Global Solutions International B.V.