Split flame burner for reducing NOx formation
US5568777A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 20, 1994 |
| Grant date | Oct 29, 1996 |
| Priority date | — |
| Expiry date | Dec 20, 2014 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF23D2201/20
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
An improved pulverized coal burner that reduces the formation of nitrogen oxides. The coal burner includes fuel splitters that separate a mixture of primary air and coal into a plurality of streams while the mixture is discharged through a diffuser having a plurality of partially open areas and a plurality of blocked areas. After passing through the diffuser, the plurality of streams are discharged into a furnace to be burned. The plurality of partially open areas and blocked areas are created by removing sections of the diffuser and replacing the removed sections with fuel splitters. Creation of these discrete streams delays mixing with secondary air. Because primary air is supplied in sub-stoichiometric quantities, the coal in these split streams will be burned under fuel-rich conditions for the first 100 to 200 milliseconds of combustion, until the delayed mixing of secondary air occurs. Combustion in a fuel-rich environment retards formation of nitrogen oxides in two ways. First, nitrogen that is part of the volatile matter that is evolved during the early stages of combustion will tend to form molecular nitrogen rather than react with oxygen to form nitrogen oxides. Second, an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.