Organic Hg has a similar boiling point to C7+hydrocarbons. Inorganic Hg is present in the forms of HgCl2, Hg organic sulfides. The most often found Hg species in natural gas are Hgoand organic Hg. Hg and As are usually present in many areas, especially Southeast Asia. Hg causes serious corrosion problem especially to pipeline in gas separation plant, aluminum heat exchangers, and gas liquefaction process, through amalgum formation. The desired limit of Hg removal is 5 ppb.