Minimum recirculation flame control (MRFC) pulverized solid fuel nozzle tip

• US 6,089,171 A
• Filed: 08/15/1997
• Issued: 07/18/2000
• Est. Priority Date: 07/08/1996
• Status: Expired due to Term

• Current Assignee: General Electric Technology GmbH (GE Vernova, Inc.)
• Original Assignee: Combustion Engineering Incorporated (ABB Limited)
• Inventors: Maney, Charles Q., Hellewell, Todd D., Towle, David P., Srinivasachar, Srivats, Lewis, Robert D., Fong, Milton A., Toqan, Majed A.
• Primary Examiner(s): Ciric, Ljiljana V.
• Application Number:
  US08/912,903
• Time in Patent Office: 1,068 Days
• Field of Search: 110/104 B, 110/260, 110/261, 110/262, 110/263, 110/264, 110/265, 110/347, 431/8, 431/173, 431/181, 431/187, 431/189, 239/423, 239/424, 239/424.5, 239/498, 239/587.5, 239/587.4, 239/419.5, 239/590.5, 239/518, 239/290, 239/299
• US Class Current: 110/263
• CPC Class Codes: F23C 5/06 Provision for adjustment of burner position during operation
• CPC Class Codes: F23C 7/02 Disposition of air supply not passing through burner to obtain a cyclonic tapering flame when burning pulverulent fuel F23C5/32
• CPC Class Codes: F23D 1/00 Burners for combustion of pulverulent fuel disposition of burners F23C
• CPC Class Codes: F23D 2201/101 tiltable

Abstract

A minimum recirculation flame control (MRFC) solid fuel nozzle tip (12) that is suited to being cooperatively associated with a pulverized solid fuel nozzle (34) of a firing system in a pulverized solid fuel-fired furnace (10). The MRFC solid fuel nozzle tip (12) includes a secondary air shroud (46), secondary air shroud support (50) operative for supporting the primary air shroud (48) relative to the secondary air shroud (46), and a splitter plate (52) mounted in supported relation within the primary air shroud (48).

Claims

1. A minimum recirculation flame control solid fuel nozzle tip for use in cooperative association with a pulverized solid fuel nozzle of a firing system of a pulverized solid fuel-fired furnace:

a. a secondary air shroud mountable in supported relation to and at one end of the pulverized solid fuel nozzle, said secondary air shroud having an inlet end and an outlet end, said secondary air shroud including a bulbous configuration at the inlet end of the secondary air shroud, said bulbous configuration being operative to minimize any bypassing of secondary air around said secondary air shroud when said secondary air shroud is in a tilted condition and and also being operative to enhance a cooling effect produced by the flow of secondary air through said secondary air shroud, said secondary air shroud also including rounded corners, said rounded corners being operative to produce higher velocities in said rounded corners of said secondary air shroud to thereby minimize low velocity regions on said secondary air shroud whereat solid fuel deposition could occur;

b. a primary air shroud mounted in supported relation within said secondary air shroud, said primary air shroud including a leading edge and a trailing edge, said trailing edge of said primary air shroud being recessed from said outlet end by an amount sufficient to remove said trailing edge of said primary air shroud as a potential surface for solid fuel particles, said primary air shroud also including rounded corners, said rounded corners of said primary air shroud being operative to increase velocities in said rounded corners of said primary air shroud thereby assisting in helping to avoid deposition of solid fuel particles at the rounded corners of the primary air shroud and if such deposition does occur assisting in effecting removal of such solid fuel particles;

c. a secondary air shroud support interposed between said secondary air shroud and said primary air shroud so as to be operative for effectuating support of said secondary air shroud relative to said primary air shroud, said secondary air shroud support being recessed from said trailing edge of said primary air shroud by an amount sufficient to keep a recirculation region and vertical deposition surface created by said secondary air shroud support away from said outlet end of said secondary air shroud so as to thereby reduce influence of said secondary air shroud support on the deposition and also sufficient to allow said outlet end of said secondary air shroud and said trailing edge of said primary air shroud to independently expand relative to one another thereby reducing thermally induces stress in the secondary air shroud and the primary air shroud; and

d. a splitter plate supported in mounted relation to and within said primary air shroud, said splitter plate being recessed from said outlet end of said secondary air shroud by an amount sufficient to remove said splitter plate as a site susceptible to potential deposition of solid fuel particles and sufficient to provide some cooling of said splitter plate by virtue of shielding provided to the splitter plate by said secondary air shroud.

2. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 1 wherein said trailing edge of said primary air shroud is tapered in order to reduce the recirculation region at said trailing edge of said primary air shroud that might otherwise be operable to draw hot particulate matter back to said trailing edge of said primary air shroud and thereby exacerbate solid fuel particle deposition at the trailing edge of the primary air shroud.

3. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 1 wherein said splitter plate includes a trailing edge and a leading edge, said trailing edge of said splitter plate being tapered at a small enough angle to avoid separation of air flowing over said splitter plate while yet remaining operative to reduce the recirculation region at said trailing edge of said splitter plate in order to thereby minimize the possibility of solid fuel deposition occurring at the trailing edge of the splitter plate.

4. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 3 wherein said leading edge of said splitter plate is tapered at an angle so as to avoid separation of air flowing over said splitter plate while yet remaining operative to reduce the recirculation region at said leading edge of said splitter plate in order to thereby minimize the possibility of solid fuel deposition occurring at the leading edge of the splitter plate.

5. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 1 wherein said secondary air shroud is uniformly spaced from said primary air shroud so as to thereby provide a uniform opening at said outlet end of said secondary air shroud and uniform secondary air distribution within the minimum recirculation flame control solid fuel nozzle tip.

6. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 1 further comprising shielding configuration interposed between said outlet end of said secondary air shroud means and said trailing edge of said primary air shroud so as to effectuate a cooling of said primary air shroud.

7. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 6 wherein said shielding configuration comprises an off-set deflector member operative to shield said trailing edge of said primary air shroud from heat that would otherwise be radiated to the primary air shroud from said secondary air shroud, said off-set deflector member further being operative to direct a portion of the secondary air flowing through said secondary air shroud in a converging manner towards said trailing edge of said primary air shroud.

8. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 6 wherein said shielding configuration comprises a converging/diverging deflector member operative to shield said trailing edge of said primary air shroud from heat that would otherwise be radiated to the primary air shroud from said secondary air shroud, said converging/diverging deflector member further being operative to direct a first portion of the secondary air flowing through said secondary air shroud in a converging manner towards said trailing edge of said primary air shroud and a second portion of the secondary air flowing through said secondary air shroud in a diverging manner away from said trailing edge of said primary air shroud.

9. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 1 wherein said splitter plate comprises a cone forming configuration operative for effecting control over flame front positioning without the creation of recirculation regions at said outlet end of said secondary air shroud and without the creation of surface features that would be susceptible to deposition of solid fuel particles on the secondary air shroud.

10. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 9 wherein said cone forming configuration includes a pair of splitter plates mounted in spaced relation one to another in supported relation within said primary air shroud, said pair of splitter plates being operative to divide the primary air/solid fuel stream flowing through said primary air shroud into two streams each capable of having a different velocity and momentum for the purpose of controlling the aerodynamics that exist at said outlet end of said secondary air shroud.

11. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 1 wherein said splitter plate comprises NO_X reduction configuration operative for minimizing NO_X emissions and for minimizing carbon in flyash.

12. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 11 wherein said NO_X reduction configuration includes a plurality of splitter plates mounted in spaced relation one to another in supported relation within said primary air shroud, and a first set of bluff bodies cooperatively associated with said plurality of splitter plates.

13. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 12 wherein said first set of bluff bodies is located at the trailing end of said plurality of splitter plates and so that each of the bluff bodies of said first set of bluff bodies projects upwardly relative to the centerline of said plurality of splitter plates.

14. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 13 wherein each of the bluff bodies of said first set of bluff bodies embodies an offset appendage.

15. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 12 wherein said NO_X reduction configuration further includes a second set of bluff bodies cooperatively associated with said plurality of splitter plates.

16. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 15 wherein said second set of bluff bodies is located at the trailing end of said plurality of splitter plates and so that each of the bluff bodies of said second set of bluff bodies projects downwardly relative to the centerline of said plurality of splitter plates.

17. The minimum recirculation flame control solid fuel nozzle tip as set forth in claim 15 wherein each of the bluff bodies of said second set of bluff bodies embodies an offset appendage.