Catalytic reduction of NOx with high activity catalysts with NH3 reductant
AssigneeExxonMobil Research and Engineering Company
InventorsAjit B. Dandekar, Richard F. Socha, Richard L. Eckes, S. Beau Waldrup, Jason M. McMullan
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Abstract
Methods and systems for selective catalytic reduction of NOx with an ammonia reductant and a zeolite catalyst loaded with at least two metals selected from the group of tungsten, cobalt, and vanadium. An exhaust stream including NOx and a reductant stream including ammonia are provided to a catalytic reactor having the metal loaded zeolite catalyst at suitable operating temperatures for NOx reduction of at least 90%.
Claims23
A method for selective catalytic reduction of NOx comprising:
- providing an exhaust stream from a combustion operation, the exhaust stream containing an amount of NOx;
- introducing at least a portion of the exhaust stream and a reductant stream including ammonia to a catalytic reactor comprising a zeolite catalyst of at least one of ZSM-5, USY, ZSM-57, and MCM-41 loaded with at least two metals selected from the group consisting of tungsten, cobalt, and vanadium, the reductant stream and the at least a portion of the exhaust stream being introduced to the catalytic reactor at suitable operating conditions to reduce the amount of NOx in the exhaust stream;
- and
- directing the NOx-reduced exhaust stream from the catalytic reactor.
A system for selective catalytic reduction of NOx comprising:
- a conduit in fluid communication with a source of an exhaust stream from a combustion operation, the exhaust stream containing an amount of NOx;
- a source of a reductant stream including ammonia;
- a catalytic reactor in fluid communication with the conduit and the source of the reductant stream, the catalytic reactor comprising at one zeolite catalyst of at least one of ZSM-5, USY, ZSM-57, and MCM-41 loaded with at least two metals selected from the group consisting of tungsten, cobalt, and vanadium, and
- configured to receive at least a portion of the exhaust stream and the reductant stream at suitable operating conditions to reduce the amount of NOx in the exhaust stream;
- and an outlet in fluid communication with the catalytic reactor to direct the NOx reduced exhaust stream from the catalytic reactor.
A catalyst for use in selective catalytic reduction of NOx, wherein the catalyst is prepared according to the procedure comprising the steps of:
- permeating into a catalytic molecular sieve comprising at least one of ZSM-5, USY, ZSM-57, and MCM-41 an amount of cobalt and tungsten to provide a metal-modified catalyst with a loading of cobalt and tungsten;
- and
- calcining the metal-modified catalyst in air to obtain a predetermined weight loading of about 6 wt. % cobalt and about 4 wt. % tungsten in the metal-modified catalyst.
Dependencies are inferred from the claim text.