Selective removal of nitrogen oxides from waste gases using V-Mo-W catalysts
AssigneeSumitomo Chemical Company, Limited
InventorsTatsuo Shiraishi, Shinkichi Shimizu, Tadashi Shindo
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Abstract
A process for selective removal of nitrogen oxides from waste gases containing 1,500 ppm or less (gas volume) of nitrogen oxides by contacting the waste gases with a metal oxide catalyst containing vanadium oxide and at least one of molybdenum oxide and tungsten oxide with an atomic ratio of the oxide forming elements of: V.sub.12-x-y Mo.sub.x W.sub.y Wherein 0.ltoreq.x.ltoreq.8, 0.ltoreq.y.ltoreq.5 and 0.3.ltoreq.x + y.ltoreq.8, at a temperature of 150.degree. to 700.degree. C in the presence of 0.3 to 4 mol of ammonia (on the basis of 1 mol of the nitrogen oxides).
Claims15
A process for the selective removal of nitrogen oxides from waste gases containing 1,500 ppm or less in gas volume of nitrogen oxides, which comprises reducing said nitrogen oxides with ammonia by contacting said waste gases with ammonia in the presence of a complex metal oxide catalyst consisting essentially of vanadium oxide and at least one member selected from the group consisting of molybdenum oxide and tungsten oxide with an atomic ratio of the oxide forming elements of:
- V.sub.12-x-y Mo.sub.x W.sub.y
- wherein 0 .ltoreq. x .ltoreq. 8, 0 .ltoreq. y .ltoreq. 5 and 0.3 .ltoreq. x + y .ltoreq. 8.
A process for the selective removal of nitrogen oxides from waste gases containing 100 to 1,500 ppm in gas volume of nitrogen oxides, which comprises reducing said nitrogen oxides with ammonia by contacting said waste gases with ammonia in the presence of a complex metal oxide catalyst consisting essentially of vanadium oxide and at least one member selected from the group consisting of molybdenum oxide and tungsten oxide with an atomic ratio of the oxide forming elements of:
- V.sub.12-x-y Mo.sub.x W.sub.y
- wherein 0 .ltoreq. x .ltoreq. 8, 0 .ltoreq. y .ltoreq. 5 and 0.3 .ltoreq. x + y .ltoreq. 8, at a temperature of 150.degree. to 700.degree. C. and at a space velocity of 2,000 to 100,000 hr.sup.-1.
A process for the selective removal of nitrogen oxides from waste gases containing 1,500 ppm or less in gas volume of nitrogen oxides, which comprises reducing said nitrogen oxides with ammonia by contacting said waste gases with ammonia in the presence of a metal oxide catalyst consisting essentially of vanadium oxide, molybdenum oxide and tungsten oxide with an atomic ratio of the oxide forming elements of:
- V.sub.12-x-y Mo.sub.x -W.sub.y
- wherein 0 .ltoreq. x .ltoreq. 4, 0 .ltoreq. y .ltoreq. 3 and 1 .ltoreq. x + y .ltoreq. 5.
Dependencies are inferred from the claim text.