Catalyst system and method for the reduction of NOx

A catalyst system for the reduction of NOx comprising:

• a catalyst comprising (i) a metal oxide catalyst support comprising alumina, (ii) at least one of gallium oxide or silver oxide present in an amount in the range of from about 5 mole % to about 31 mole %;
• and (iii) a promoting metal or a combination of promoting metals present in an amount in the range of from about 1 mole % to about 22 mole % and selected from the group consisting of silver;
• cobalt;
• molybdenum;
• tungsten;
• indium and molybdenum;
• indium and cobalt;
• and indium and tungsten;
• and
• a gas stream comprising (A) water in a range of from about 1 mole % to about 12 mole %;
• (B) oxygen in a range of from about 1 mole % to about 15 mole %;
• and (C) an organic reductant comprising oxygen and selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof;
• wherein said organic reductant and said NOx are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1.

A method for reducing NOx, which comprises the steps of:

• providing a gas stream comprising (A) NOx ;
• (B) water from about 1 mole % to about 12 mole %;
• (C) oxygen from about 1 mole % to about 15 mole %;
• and (D) an organic reductant comprising oxygen selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof;
• and
• contacting said gas stream with a catalyst comprising (i) a metal oxide catalyst support comprising at least one member selected from the group consisting of alumina, titania, zirconia, silicon carbide, and ceria;
• (ii) at least one of gallium oxide or silver oxide in the range of from about 5 mole % to about 31 mole %;
• and (iii) a promoting metal or a combination of promoting metals in the range of from about 1 mole % to about 22 mole % and selected from the group consisting of silver;
• cobalt;
• molybdenum;
• tungsten;
• indium and molybdenum;
• indium and cobalt;
• and indium and tungsten;
• wherein said organic reductant and said NOx are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1;
• and wherein said contact is performed at a temperature in a range of from about 100° C. to about 600° C. and at a space velocity in a range of from about 5000 hr−1 to about 100000 hr−1.