REMOVAL OF MERCAPTANS FROM HYDROCARBON STREAMS USING IONIC LIQUIDS

摘要

Methods for removing mercaptans from hydrocarbons streams, for example crude oil and natural gas, are provided. The methods use basic metal salts which react with mercaptans to form mercaptides. The metal salts are dissolved or suspended in ionic liquids, which tend to have virtually no vapor pressure. After the mercaptides are adsorbed into the ionic liquid, the demarcaptanized hydrocarbon stream can be removed, for example by distillation, decantation or gravity separation. Then the mercaptides can be oxidized, for example, by exposure to air, to form disulfides. The disulfides are insoluble in the ionic liquids, and can be readily removed. Sodium hydroxide is a preferred salt. Non-water reactive ionic liquids are preferred. The mercanptan-containing hydrocarbon stream can be in the gas phase or in the liquid phase. The flow of hydrocarbon stream over/through the ionic liquid can be for example, co-current, counter-current, or staged in stirred tanks, with countercurrent being preferred.