Reduction of nitrogen oxides with catalytic acid resistant aluminosilicate molecular sieves and ammonia

Claim 2

A process for converting more than 98% of the noxious nitrogen oxides present in gaseous effluents containing 3 to 20 volume percent oxygen to N 2 and N 2 O comprising mixing the gaseous effluent with a gas stream containing an effective amount of ammonia and contacting the mixed gases with a catalyst consisting essentially of a synthetic hydrogen mordenite having pore openings of 3 to 10 A, the temperature of the catalyst bed being 250°-550° C. at the bed exit.

Claim 3

A process according to claim 1 wherein the gaseous effluent contains 16 to 20% oxygen.

Claim 4

A process according to claim 1 wherein the gaseous effluent is stack gas from a fossil-fuel-fired power plant including the following: 7 volume percent water vapor, 12 volume percent CO 2 , 0.3 volume percent SO 2 and 0.05 volume percent NO, and 3 to 7 volume percent 0 2 and the bed temperature is 350° C. at the bed exit.

Claim 5

A process according to claim 1 wherein the gaseous effluent is stack gas from a nuclear processing plant having the following approximate composition: 30 volume percent water vapor, 5 volume percent CO 2 , 2 volume percent CO, 0.9 volume percent NO 2 , 0.4 volume percent NO, the balance being air and the bed temperature is 400°-500° C. at the bed exit.

Claim 6

A process according to claim 1 wherein the gaseous effluent is stack gas from an industrial plant having approximately the following composition: 10 volume percent water vapor, 0.5 volume percent NO 2 , the balance being air and the bed temperature is 350° C. at the bed exit.

Claim 7

A process for selectively reducing oxides of nitrogen present in a mixture of gases containing oxygen, reducible oxides of nitrogen and an inert gas, which comprises contacting in a reaction zone said mixture of gases and an approximately stoichiometric amount of ammonia based on reduction of the nitrogen oxides present to nitrogen at a temperature of 250° to 550° C. in the presence of a catalyst consisting of an acid resistant aluminosilicate molecular sieve having substantially uniform intercrystalline pores whereby selective reduction of the oxides of nitrogen to nitrous oxide and nitrogen is effected.

Claim 8

A process for selectively reducing oxides of nitrogen present in a mixture of gases containing oxygen, reducible oxides of nitrogen and an inert gas, which comprises contacting in a reaction zone said mixture of gases and an approximately stoichiometric amount of ammonia based on reduction of the nitrogen oxides present to nitrogen at a temperature of 250° to 550° C. in the presence of a catalyst consisting of an acid resistant aluminosilicate molecular sieve having substantially uniform intercrystalline pores whereby selective reduction of the oxides of nitrogen to nitrous oxide and nitrogen is effected.

Claim 9

A process for selectively reducing oxides of nitrogen in a mixture of gases containing up to 20% oxygen, up to 1.0% NO or NO 2 and the remainder an inert gas, which comprises contacting in a reaction zone said mixture of gases and an approximately stoichiometric amount of ammonia based on reduction of nitrogen oxides present to nitrogen at a space velocity of less than 36,000 hr -1 and a temperature within the range of 250° C. to 550° C. in the presence of a catalyst consisting of an acid resistant aluminosilicate molecular sieve composition having substantially uniform intercrystalline pores with diameters of about 3 to 10 A, whereby selective reduction of the oxides of nitrogen to nitrous oxide and nitrogen is effected.

Claim 10

A process for selectively reducing oxides of nitrogen in a mixture of gases containing up to 20% oxygen, up to 1.0% NO or NO 2 and the remainder an inert gas, which comprises contacting in a reaction zone said mixture of gases and an approximately stoichiometric amount of ammonia based on reduction of nitrogen oxides present to nitrogen at a space velocity of less than 36,000 hr -1 and a temperature within the range of 250° C. to 550° C. in the presence of a catalyst consisting of an acid resistant aluminosilicate molecular sieve composition having substantially uniform intercrystalline pores with diameters of about 3 to 10 A, whereby selective reduction of the oxides of nitrogen to nitrous oxide and nitrogen is effected.

Claim 11

A process for selectively reducing oxides of nitrogen in a mixture of gases containing up to 20% oxygen, from a trace to 2% oxides of nitrogen and the remainder an inert gas, which comprises contacting in a reaction zone said mixture of gases and an approximately stoichiometric amount of ammonia based on reduction of nitrogen oxides present to nitrogen at a space velocity of less than 36,000 hr -1 and at a temperature within the range of 250° C. to 550° C. in the presence of a catalyst consisting of an acid resistant aluminosilicate molecular sieve composition having substantially uniform intercrystalline pores with diameters of about 3-10 A, whereby selective reduction of the oxides of nitrogen to nitrous oxide and nitrogen is effected.

Claim 12

A process for selectively reducing oxides of nitrogen in a mixture of gases containing up to 20% oxygen, from a trace to 2% oxides of nitrogen and the remainder an inert gas, which comprises contacting in a reaction zone said mixture of gases and an approximately stoichiometric amount of ammonia based on reduction of nitrogen oxides present to nitrogen at a space velocity of less than 36,000 hr -1 and at a temperature within the range of 250° C. to 550° C. in the presence of a catalyst consisting of an acid resistant aluminosilicate molecular sieve composition having substantially uniform intercrystalline pores with diameters of about 3-10 A, whereby selective reduction of the oxides of nitrogen to nitrous oxide and nitrogen is effected.