Hg removal from hydrocarbon liquid using polysulfide

Some crudes and condensates are known to contain a small quantity of Hg. A process has been devised to remove up to 80-90% of this Hg from the oil. In the process, the oil is washed with an aqueous solution containing 50 to 1 000 ppm of Na2Sx. The efficacy and the feasibility of the process concept have been demonstra ted in the laboratory using both batch and flow systems. When the Na2Sx con centration in the treating solution was higher than 100 ppm, the Hg removal reaction was mass transfer limited. By Increasing mixing intensity and the number of contacting stages, Hg was removed from 200 to 10 ppb using a sol ution of 500 ppm Na2Sx. The mixing can be accomplished using one on-line ce ntrifugal pump and preferably two in series. Phase separation between the aqueous solution and the oil product was rapid . In the process, the sulfur contamination of the oil product, due to Na2Sx , was low.