Method and apparatus for reducing nitrogen oxides using spatially selective cooling
US5690039A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1996 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Jun 17, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF23L7/002
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A method and apparatus are described for reducing NO.sub.x in a combustion zone such as a boiler by spatially selectively injecting a cooling fluid into the combustion zone so that the fluid is entrained to intersect an identifiable NO.sub.x producing zone. The cooling fluid can be water or a gas or mixture of them and whose temperature is sufficiently low or whose combined mass flow and temperature are sufficiently low so that the cooling fluid can reach the NO.sub.x producing zone and cool it to a temperature where the NO.sub.x production is significantly reduced. In one embodiment of the invention a cyclone boiler has a number of identifiable NO.sub.x producing zones. Several of these are targeted by spatially distinct cooling fluid streams placed at strategic locations. At one location the cooling fluid such as a water spray is placed in a duct in the path of the secondary air to deliver a cooling secondary air stream or a combination thereof with a hot flue gas and which is shaped to correspond in cross-section to that of the NO.sub.x producing zone targeted by the cooling fluid. Significant NO.sub.x reduction is achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.