Method and system for the removal of particulate matter and noxious compounds from flue-gas using a ceramic filter with an SCR catalyst

Patent metadata

Field	Value
Publication number	US-11007479-B2
Application number	US-201816608715-A
Country	US
Kind code	B2
Filing date	Apr 5, 2018
Priority date	Apr 26, 2017
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

Method and system for the removal of nitrogen oxides, from flue gas at low temperatures.

First claim

The invention claimed is:

1. A method for the removal of nitrogen oxides from flue gas from combustion facilities, comprising the steps of
passing the flue gas through one or more ceramic filter catalysed with a catalyst for selective reduction of nitrogen oxides in presence of ammonia added to the flue gas either as such or in form of a precursor thereof;
at a temperature below 250° C. injecting an effluent gas containing nitrogen dioxide into the flue gas upstream the one or more ceramic filters;
providing the effluent gas containing nitrogen dioxide by steps of
catalytically oxidizing ammonia or a precursor thereof with an oxygen containing atmosphere to an effluent gas containing nitrogen monoxide and oxygen in presence of an oxidation catalyst;
cooling the effluent gas to ambient temperature and oxidizing the nitrogen monoxide in the cooled effluent gas to the nitrogen dioxide containing effluent gas.

2. The method of claim 1 , wherein the oxygen containing atmosphere comprises flue gas.

3. The method of claim 1 , wherein the oxygen containing atmosphere is ambient air.

4. The method according to claim 1 , wherein the nitrogen dioxide containing effluent gas is injected into the flue gas in an amount resulting in 45 to 55% by volume of the nitrogen oxides is nitrogen dioxide at inlet to the catalyst for selective reduction of nitrogen oxides.

5. The method according to claim 1 , wherein the oxidation of the nitrogen monoxide in the cooled effluent gas to the nitrogen dioxide containing effluent gas is performed in presence of an oxidation catalyst.

6. The method according to claim 1 ,
wherein the one or more ceramic filters are in form of ceramic candle filters.

7. System for use in the method according to claim 1 , comprising within a flue gas duct a filter house with one or more ceramic filters catalysed with a catalyst for selective reduction of nitrogen oxides;
upstream the one or more ceramic filters or the filter house injection means for injection of ammonia or a urea solution into the flue gas duct;
upstream the one or more ceramic filters or the filter house, injection means for injection of nitrogen dioxide containing effluent gas; and
outside the flue gas duct,
an ammonia oxidation catalyst unit; and
means for cooling and oxidizing nitrogen monoxide containing effluent gas withdrawn from the ammonia oxidation catalyst to the nitrogen dioxide containing effluent gas connected at its outlet end to the injection means for injection of the nitrogen dioxide containing effluent gas.

8. The system of claim 7 , wherein the means for cooling and oxidizing the nitrogen monoxide containing effluent gas is in form of a heat exchanger.

9. The system of claim 7 , wherein the means for cooling and oxidizing the nitrogen monoxide containing effluent gas is in form of a spirally wound tube.

10. The system of claim 7 , wherein the means for the cooling and oxidizing nitrogen monoxide containing effluent gas is provided with an oxidation catalyst.

11. The system of claim 7 , wherein the one or more ceramic filters are in form of ceramic candle filters.

Assignees

• Haldor Topsoe As

Inventors

• GABRIELSSON Pär L T

Classifications

• B01J21/18

  Carbon · CPC title

• B01D2258/0283

  Flue gases · CPC title

• B01D2251/2062

  Ammonia · CPC title

• B01D53/8625 Primary

  Nitrogen oxides · CPC title

• B01D53/90

  Injecting reactants · CPC title