Simplified efficient process for reducing NO.sub.x, SO.sub.x, and particulates
US5658547A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1995 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | Mar 16, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A50/20
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The removal of SO.sub.x and particulates, and preferably also NO.sub.x, from the combustion gases of a large boiler, is simplified while efficiency is improved. In a primary treatment zone, a slurry comprising an alkaline SO.sub.x -reducing composition and preferably a nitrogen-containing composition effective to reduce NO.sub.x, is introduced into combustion gases at a temperature of from about 900.degree. to about 1300.degree. C. The gases are cooled by initial contact with steam-generating means, and then by contact with an gas-to-gas heat exchanger. Cooled gases are then subjected to a secondary treatment in which they are first humidified and further cooled by introduction of a water spray or aerosol to reduce the temperature to 100.degree. C. or below. Contact between the SO.sub.x -reducing composition and the humidified gases is maintained for a reaction period of at least 2 seconds. Particulate solids are then separated from the gases with a fabric filter. The cleaned gases are reheated by the gas-to-gas heat exchanger prior to discharge to the atmosphere. Reductions of SO.sub.x of greater than 80% are achieved, preferably 90 to 95%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.