DMC-2 process of oil and gas condensate treatment

DMC-2 process is used for treatment of light oil for hydrogen sulfide and low molecular weight С₁–С₃ mercaptans without contact of the oil with air. The process consists in extraction of С₁–С₃ mercaptans and hydrogen sulfide with 10–20 % aqueous solution of sodium hydroxide with its subsequent regeneration by catalytic oxidation of the extraction products with air oxygen.

The extraction of mercaptans and hydrogen sulfide proceeds in mixer М-1, wherein the stabilized feed and alkaline solution are supplied simultaneously. Then the oil and alkaline solution mixture flows to gravity separator V-1, where the demercaptanized oil is separated from the alkaline solution and sent from the top of V-1 to storage tanks.

The alkaline solution and extraction products – sodium sulfide and mercaptides – flow from the bottom of V-1 to the bottom of regenerator R-1, wherein process air is also supplied from a compressor. The alkaline solution regeneration takes place in the regenerator at a temperature of 50–55^о С and a pressure of 0.4–0.5 МPa over IVKAZ catalyst by oxidation of sodium sulfide and mercaptides with air oxygen.

From the top of R-1 the reaction mixture flows to air separator V-2, from the top of which the spent air is sent to incineration and from the bottom of V-2 the regenerated alkaline solution is sent with pump Р-1 to mixer М-1. The disulfides entering М-1 together with the alkaline solution pass into the oil phase. If necessary, the disulfides can be separated from the regenerated alkaline solution.

On the basis of DMC-2 technology two plants of Tengiz oil treatment for 6 MM t/yr capacity have been operating since 2006 on JV “Tengizchevroil” (Republic of Kazakhstan). DMC-2 plants were put into operation by modification of DMС-1 plants.