The most efficient and energy-conserving process for treating oil with high hydrogen sulfide content is liquid-phase oxidation using aqueous-ammonia solutions of IVKAZ catalyst. The oxidation proceeds with formation of elemental sulfur following an irreversible reaction at a high velocity.
H2 S + NH4OH → NH4SH + H2O
NH4SH + 0.5 O2 → NH4SH + S0
The process is carried out at mild conditions: pressure of 10 barg and temperature of 30-60 0С. The catalyst complex consumption is ~ 1-2 l/t of feed.
The ammonia solution of IVKAZ catalyst complex (CC) is prepared in vessel V-1. The stabilized oil is sent with pump P-1 via mixer M-1 to oxidation reactor R-1. The CC solution and compressed air from compressor С-1 are supplied with dosing pump DP-1 to oil line before mixer M-1. The CC and process air consumption are set proportionally to oil consumption and to hydrogen sulfide content in the oil. The mixture of the oil and CC, containing the dissolved air, enters reactor R-1, where oxidation of hydrogen sulfide to elemental sulfur takes place.
Then the mixture of the oil and CC, containing the dissolved spent air, is sent to settling separator S-2, where at a pressure decrease the mixture is separated to two phases. The separated spent air and light hydrocarbon gases are sent from the top of S-2 to a flare. The treated oil is sent with pump P-2 from S-2 to a pipeline. The separated CC is returned as a recycle into the oxidation reactor.
The DМС-1МА process was tested successfully in 2012 on “Nurlatneft” plant of ОJS «ТАТNEFT». The plant capacity is 150 m3/hr. Hydrogen sulfide content in the feed is 350-530 ppm, in the treated oil it is below 10 ppm.
DMC-1MA process flow diagram