Removal of organosulfurs from liquefied petroleum gas in a fiber film contactor using a new formulated solvent

• H2S and organosulfurs in LPG are efficiently removed by a formulated solvent in a fiber film contactor.
• Mass transfer rates of the process studied here and the conventional treating process are compared.
• The optimum removal of total organosulfur is above 93%.

H2S and organosulfurs were simultaneously removed from delayed coking LPG in a fiber film contactor using several formulated solvents (named UDS-I, UDS-II, UDS-III, and UDS-IV). The mass transfer rate of organosulfurs in the proposed process was compared with that of conventional countercurrent columns using N-methyldiethanolamine (MDEA) solvent in terms of three aspects. Additionally, the optimum solvent was observed and the influences of operation conditions on desulfurization performance were systemically investigated. The results indicate that the fiber film contactor has greater mass transfer area than conventional countercurrent columns. UDS-IV solvent possesses the highest total removal of organosulfurs, which is 45.7 percentage points higher than that of MDEA. Meanwhile, the distribution ratios of organosulfurs in UDS-IV/LPG system are found 7–10 times as high as those in MDEA/LPG system. The diffusion coefficients for organosulfurs in UDS-IV solution are found the highest, up to 1.08 times as high as those in MDEA solution. As a result, the process combining UDS-IV solvent and the fiber film contactor exhibits excellent performance for simultaneously removing H2S and organosulfurs, owing to the increase in mass transfer area, driving force and mass transfer coefficient. Under optimum operation conditions, UDS-IV solvent can reduce the contents of H2S and total sulfur in the LPG to less than 1 and 240 mg/Nm3, respectively, and the total removal of organosulfurs is above 93%.