Claims
- 1. In a fluid fuel burner positioned in a furnace opening for minimum production of NOx burner under variable rates of fuel supply having a refractory lined first combustion space with an opening thereto which contains a centrally located pre-combustion space opening into said first combustion space and having a liquid fuel nozzle therein; a plurality of coaxially located gaseous fuel nozzles for directing gaseous fuel from a gaseous fuel source into said first combustion space, a primary combustion air chamber surrounding said liquid fuel nozzle for introduction of primary combustion air into said pre-combustion chamber, means to supply secondary air into a first annular space formed between the opening in said first combustion space and said pre-combustion space, the total of said primary and secondary air being supplied from a single controllable source and thence divided into said primary and secondary portions, a second annulus between said first combustion space and said furnace opening to supply tertiary air from a separate controllable source to immediately downstream of said first combustion space and means to ignite the resulting combustion fuel-air mixture, the improvement comprising means to control the amount of primary air into said pre-combustion chamber and means to simultaneously control the single controllable source of said primary-secondary air and the separate controllable source of said tertiary air whereby the total of said primary-secondary air in the first space is less than stochiometric while the amount of tertiary air will make the total air greater than the stoichiometric requirements of the fuels being burned.
- 2. The system as in claim 1 wherein the total of primary and secondary air is in the range of 60 to 75% of the total air requirements for stoichiometric burning.
- 3. The system as in claim 1 in which said means to control said primary combustion air chamber comprises:
- (a) a centrally located inner cylindrical wall through which said primary air flows, said wall positioned within a plenum which receives said primary and secondary air;
- (b) a plurality of symmetrically-spaced circumferential openings in said inner wall for the passage of said primary air from said plenum; each of said openings of selected angular width W and length P;
- (c) a rotatable cylindrical continguous sleeve surrounding said wall and means for rotating said sleeve;
- (d) a corresponding set of openings in said sleeve as in said wall;
- whereby as said sleeve is rotated said openings in said wall can be completely open or partially open as desired;
- whereby the ratio of primary to secondary air can be controlled.
- 4. The system as in claim 1 including water atomization means in the vicinity of said fuel burner and upstream thereof.
CROSS REFERENCE TO RELATED APPLICATION AND PATENT
This continuation-in-part application is an improvement over pending application Ser. No. 916,766, filed June 19, 1978, now U.S. Pat. No. 4,257,763.
Ser. No. 916,766 now U.S. Pat. No. 4,257,763 is entered into this Application by reference.
US Referenced Citations (11)
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
916766 |
Jun 1978 |
|