Low NO.sub.x combustion process and system
US5178101A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 9, 1992 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Mar 9, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02C20/10
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method and corresponding system are provided for reducing quantities of oxides of nitrogen, including N.sub.2 O, that are generated in a coal-fired fluidized bed boiler, the exhaust stream from the fluidized bed boiler being at a temperature of about 600.degree.-650.degree. F. and including from about 3 to 6% oxygen, from about 50 to 500 ppmv of NO.sub.x and from about 50 to 300 ppmv of N.sub.2 O. Pursuant to the invention, the exhaust stream is flowed through a thermal reaction zone at which fuel and air are burned, to provide a modified heated stream which includes small quantities of combustibles and of oxygen. The modified heated stream is passed over a first catalyst bed under overall reducing conditions, the quantity of oxygen in the stream being in stoichiometric excess of the amount of NO.sub.2 O and NO.sub.x, but less than the amount of said combustibles; whereby the N.sub.2 O and NO.sub.x are first oxidized to NO.sub.2, and then the NO.sub.2 is reduced by the excess combustibles. The stream from the first catalyst bed is cooled by passing it through a heat exchanger. Air is added to the resulting stream from the heat exchanger to produce a further cooled stream having a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.