Catalyst and catalytic reduction
AssigneeBritish Technology Group Limited
InventorsFreek Kapteijn, Lydia Singoredjo
Life of this patent
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Abstract
A catalyst for the selective reduction of nitric oxide NO in flue gas to nitrogen using ammonia NH.sub.3 comprises oxidatively heat treated manganese oxide loaded on a porous substrate of gamma-alumina or titania- or titania-/WO.sub.3 -modified silica.
Claims16
Process for preparing a catalyst for the reduction of nitrogen oxide, said process consisting essentially of the steps of:
- applying a solution consisting of a manganese organic salt in a solvent to a porous inorganic carrier of gamma alumina;
- removing said solvent;
- subjecting said carrier to a heat treatment which oxidizes Mn(II), said heat treatment including at least one of the heating steps selected from the group consisting of:
- from 275.degree. to 350.degree. C. for at least 12 hours,
- from 350.degree. to 455.degree. C. for at least 4 hours, and
- from 455.degree. to 555.degree. C. for at least 11/2 hours.
Process for preparing a catalyst for the reduction of nitrogen oxide, said process consisting essentially of the steps of:
- applying a solution consisting of a manganese organic salt in a solvent to a porous inorgangic carrier of gamma alumina;
- removing said solvent;
- subjecting said carrier to a heat treatment by heating from 250.degree. C. to above 350.degree. C. to oxidize Mn(II) with oxygen, said heat treatment being carried out such that at least 1 hour elapses from passing 250.degree. C. to passing 350.degree. C.
Process for preparing a catalyst for the reduction of nitrogen oxide, said process consisting essentially of the steps of:
- applying a solution consisting of a manganese (II) compound in a solvent to a porous inorganic carrier of gamma alumina;
- removing said solvent;
- and
- subjecting said carrier to a heat treatment by heating from 250.degree. C. to above 350.degree. C. to oxidize Mn (II) with oxygen, said heat treatment being carried out at a temperature which does not exceed 575.degree. C. and such that at least one hour elapses from passing 250.degree. C. to passing 350.degree. C.
Process for preparing a catalyst for the reduction of nitrogen oxide, said process consisting essentially of the steps of:
- applying a solution consisting of a manganese organic salt in a solvent to a porous inorganic carrier of gamma alumina;
- removing said solvent;
- subjecting said carrier to a heat treatment which oxidizes Mn (II), said heat treatment including at least one of the heating steps selected from the group consisting of:
- from 275.degree. to 350.degree. C. for about 12-48 hours,
- from 350.degree. to 455.degree. C. for about 4 to 18 hours, and
- from 455.degree. to 555.degree. C. for about 11/2 to 6 hours.
Process for preparing a catalyst for the reduction of nitrogen oxide, said process consisting essentially of the steps of:
- applying a solution consisting of a manganese (II) compound in a solvent to a porous inorganic carrier of gamma alumina;
- loading the carrier with titanium dioxide or with tungsten trioxide or with both before or after but not at the same time as applying the manganese (II) compound;
- removing the solvent;
- subjecting the carrier to a heat treatment by heating from 250.degree. C. to above 350.degree. C. to oxidize Mn (II) with oxygen, said heat treatment being carried out such that at least one hour elapses from passing 250.degree. C. to passing 350.degree. C.
Dependencies are inferred from the claim text.