METHOD OF REMOVING ORGANOSULFUR COMPOUNDS FROM HYDROCARBON STOCK Russian patent published in 1999 - IPC

FIELD: petroleum processing and petrochemical industry. SUBSTANCE: purification of hydrocarbon stock from organosulfur compounds is accomplished via oxidation of these compounds by contacting liquid hydrocarbon stock with working solution, in particular, sulfuric acid aqueous solution containing vanadium in oxidation state exceeding its minimum oxidation state value, after which resulting mixture is separated to yield purified liquid hydrocarbon stock and exhausted working solution containing vanadium reduced to oxidation state below its maximum value, and working solution is then regenerated. The latter operation is performed by precipitating reduced vanadium in the form of solid precipitate containing vanadium sulfates and their hydrates, separating and thermally decomposing solid precipitate into solid vanadium oxide and gaseous heat decomposition products, dissolving vanadium oxide in exhausted working solution to give regenerated working solution containing pentavalent vanadium predominantly in the form of ions bound to oxygen, hydrogen, and sulfur ions and/or atoms, to water molecules and/or sulfuric acid residues, and also nondissociated vanadium oxide molecules and/or their colloid particles. Precipitation is carried out by saturation and subsequent supersaturation of exhausted working solution with reduced vanadium, which is accomplished by reduction of vanadium in higher oxidation state by organosulfur compounds present in hydrocarbon stock. Heat decomposition of vanadium sulfate and/or acid hydrates of vanadyl sulfate proceeds simultaneously with oxidation of sulfur dioxide into sulfur trioxide at 450 to 550 C. Working solution is saturated with pentavalent vanadium by dissolving vanadium oxide obtained upon heat decomposition of solid precipitate, working solution containing 4-12 (preferably 6-10) M sulfuric acid. Concentration of vanadium in oxidation state exceeding its minimum value is usually at least 0.01 that of concentration of saturated solution of metal ions in sulfuric acid solution. Liquid hydrocarbon material is brought into contact with working solution in emulsion conditions. Sulfur trioxide obtained is dissolved in water to form sulfuric acid solution that is further added to working solution. Sulfur dioxide oxidation is carried out in presence of oxygen and vanadium catalyst at 400-700 C. Exhausted working solution separated from hydrocarbon material is fried of gum-like oxidation products by centrifugation and/or filtration. Separated hydrocarbon stock is fried of acid components and gum-like oxidation products by centrifugation followed by filtration using inert or alkaline filter material. Purified hydrocarbon stock is then distilled. EFFECT: enhanced purification efficiency and reduced power consumption. 15 cl, 1 dwg, 1 tbl