Burner for operating a heat generator

• US 6,019,596 A
• Filed: 11/17/1998
• Issued: 02/01/2000
• Est. Priority Date: 11/21/1997
• Status: Expired due to Fees

• Current Assignee: Alstom SA
• Original Assignee: ABB Research Ltd. (ABB Ltd.)
• Inventors: Ruck, Thomas, Knopfel, Hans Peter
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): LEE, DAVID B
• Application Number:
  US09/192,512
• Time in Patent Office: 441 Days
• Field of Search: 431/350, 431/351, 431/352, 431/353, 431/8, 431/9, 431/11, 431/166, 431/167, 431/243, 60/39.23, 60/737, 60/752, 60/756, 60/757, 239/132.5
• US Class Current: 431/350
• CPC Class Codes: F23C 15/00 Apparatus in which combustion takes place in pulses influenced by acoustic resonance in a gas mass for generating combustion products of high pressure or high velocity F23R7/00; starting devices F23D11/42
• CPC Class Codes: F23C 2900/07002 Premix burners with air inlet slots obtained between offset curved wall surfaces, e.g. double cone burners
• CPC Class Codes: F23C 7/002 the air being submitted to a rotary or spinning motion cyclonic combustion chamber F23C3/006
• CPC Class Codes: F23C 7/06 for heating the incoming air arrangements of regenerators and recuperators F23L15/00
• CPC Class Codes: F23D 11/402 Mixing chambers downstream of the nozzle
• CPC Class Codes: F23D 14/02 Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
• CPC Class Codes: F23D 14/78 Cooling burner parts
• CPC Class Codes: F23D 17/002 gaseous or liquid fuel
• CPC Class Codes: F23D 2209/10 Flame flashback
• CPC Class Codes: F23D 2214/00 Cooling

Abstract

In a burner for operating a combustion chamber, which burner essentially comprises a swirl generator (100), a transition piece (200) arranged downstream of the swirl generator, and a mixing tube (20), transition piece (200) and mixing tube (20) forming the mixing section of the burner and being arranged upstream of a combustion space (30), there are means (302, 303, 304) in the lower region of the mixing tube (20) which bring about cooling of the base plate (305) forming a front wall. The air quantity (307) used here is passed into the flow (40) of the mixing tube (20). A leaner mixing and lower NOx emissions are thereby achieved.

Claims

1. A burner comprising:

a swirl generator for admitting a combustion-air flow and including at least one fuel nozzle for injecting at least one fuel into the combustion-air flow and forming a flow in a direction through the swirl generator to a mixing section and to a combustion space, thereby defining a downstream flow direction, a mixing section being arranged downstream of the swirl generator and having, inside a first part of the mixing section in the downstream direction of flow, at least one transition passage for passing the flow formed in the swirl generator into a mixing tube arranged downstream of the at least one transition passage, and the mixing tube being arranged in an upstream flow direction from the combustion space and having at least one bore which runs through a wall of the mixing tube, including a means in a downstream region of the mixing tube for cooling a base plate formed by a front wall of the combustion space whereby the means for cooling includes an ambient air quantity which performs cooling by way of impingement cooling, and wherein the ambient air quantity used with the means for cooling is passed into the flow in the mixing tube through the at least one bore which runs through the wall of the mixing tube.

2. The burner as claimed in claim 1, wherein the swirl generator includes at least two hollow, conical sectional bodies which are nested one inside the other along the downstream direction of flow, wherein respective longitudinal symmetry axes of the sectional bodies run mutually offset such that adjacent walls of the sectional bodies form ducts extending tangentially relative to the longitudinal symmetry axes of the sectional bodies, for admitting the combustion-air flow, and wherein the at least one fuel nozzle is arranged in an interior space formed by the at least two hollow, conical sectional bodies.

3. The burner as claimed in claim 2, wherein further injection openings are arranged longitudinally along the tangentially extending ducts.

4. The burner as claimed in claim 2, wherein the sectional bodies have a blade-shaped profile in cross section.

5. The burner as claimed in claim 2, wherein the sectional bodies are nested spirally one inside the other.

6. The burner as claimed in claim 1, wherein the base plate forming the front wall is extended on the combustion-space side by a breakaway edge.

7. The burner as claimed in claim 1, wherein the at least one transition passage in the mixing section corresponds to a number of partial flows forming the flow formed by the swirl generator.

8. The burner as claimed in claim 1, wherein the at least one bore which runs through the wall of the mixing tube runs at an acute angle relative to a longitudinal burner axis.

9. The burner as claimed in claim 1, wherein there is an increase in cross section between the cross-section of the mixing section and the cross-section of the combustion space, which increase in cross section induces the initial cross section of flow of the combustion chamber, and wherein a backflow zone can take effect in the region of this increase in cross section.