(135c) Mercury Removal From Liquid Hydrocarbons in Ethylene Plants

Mercury is found in an ever-increasing number of hydrocarbons worldwide. The level of mercury can vary significantly depending on location. The situation is made more complex in refineries and petrochemical plants, as liquid feedstocks can contain elemental, organic, and inorganic species. Complete removal of mercury is advisable to avoid catastrophic failures in cryogenic equipment, to prevent poisoning of process catalysts and for health and safety reasons. The new generation of PURASPEC absorbents has been shown to give effective removal and long life without impacting negatively on product quality. There are now over 70 PURASPEC mercury removal units (MRUs) in service on a range of hydrocarbons with over 30 units in commercial operation on liquid applications, with three in ethylene plant condensate service. This paper describes absorbent technology using sulfided mixed metals to sequester mercury. This technology is illustrated in examples of applications upstream of the cracking heaters and downstream in the distillation train. This paper includes actual operating experience at Petkim Petrokimya in condensate feedstock treating.