Removal of oxides of nitrogen from gases in multi-stage coal combustion
US5706645A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 10, 1996 |
| Grant date | Jan 13, 1998 |
| Priority date | — |
| Expiry date | Apr 10, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E50/10
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
Polluting NO.sub.x gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO.sub.x gases are removed is directed to introducing NO.sub.x -free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.