Coal nozzle assembly for a steam generation apparatus

Patent metadata

Field	Value
Publication number	US-11326774-B2
Application number	US-201816635005-A
Country	US
Kind code	B2
Filing date	Jul 26, 2018
Priority date	Jul 31, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A steam generating system includes a nozzle assembly for pulverized coal and air, the coal nozzle assembly comprises an inner housing (3) for conveying primary air and coal and an outer housing (5) for conveying secondary air to an exit face (13) of a nozzle tip (1), wherein the outer housing (3) and the inner housing (5) are arranged coaxially and limit a channel (15) for the secondary air, wherein the cross-sectional area (AIH) of the inner housing (3) increases towards the exit face (13) of the nozzle tip (1), wherein the cross-sectional area (AOH) of the outer housing (5) decreases towards the exit face (13), and wherein bars (11) are located in the inner housing (3) near the exit face (13) that accelerate the velocity of the primary air and coal particles.

First claim

The invention claimed is:

1. A coal nozzle assembly for a steam generation apparatus, comprising:
an inner housing for conveying primary air and coal through a nozzle tip toward an exit face;
an outer housing for conveying secondary air through the nozzle tip;
at least one bar located in the inner housing near the exit face; and
a cover plate downstream of the at least one bar to prevent abrasion of the trailing edges of the at least one bar,
wherein the outer housing and the inner housing are arranged coaxially and limit a channel for the secondary air,
wherein the cross-sectional area (A IH ) of the inner housing increases towards the exit face of the nozzle tip,
wherein the cross-sectional area (A OH ) of the outer housing decreases towards the exit face.

2. The coal nozzle assembly according to claim 1 , wherein the inner housing has a square or rectangular cross-section.

3. The coal nozzle assembly according to claim 1 , wherein the outer housing has a square or rectangular cross-section.

4. The coal nozzle assembly according to claim 1 , wherein the at least one bar extends between two opposite walls of the inner housing.

5. The coal nozzle assembly according to claim 1 , wherein the at least one bar comprises two or more bars extending between two opposite walls of the inner housing and being arranged parallel to each other.

6. The coal nozzle assembly according to claim 5 , wherein the bars are arranged as a grid.

7. The coal nozzle assembly according to claim 1 , wherein the relation between the cross section Area (A IH ) of the inner housing at the entrance of the primary air and the exit face is within a range of 1.2 to 1.5.

8. The coal nozzle assembly according to claim 7 , wherein the relation between the cross section Area (A IH ) of the inner housing at the entrance of the primary air and the exit face is 1.3.

9. The coal nozzle assembly according to claim 1 , wherein the at least one bar reduces the cross section Area (A IH ) of the inner housing at the exit face by a factor within the range of 0.2 to 0.5.

10. The coal nozzle assembly according to claim 9 , wherein the factor is 0.25.

11. The coal nozzle assembly according to claim 1 , wherein the relation between the cross section Area (A OH ) of the outer housing at the entrance of the primary air and the exit face is 0.4.

12. The coal nozzle assembly according to claim 1 , wherein the relation between the cross section Area (A OH ) of the outer housing at the entrance of the primary air and the exit face is within a range of 0.3 to 0.5.

13. The coal nozzle assembly according to claim 1 , wherein a catalyst is applied to the internal walls of the nozzle tip, wherein the catalyst is applied to the inner surface of the inner housing and/or the at least one bar.

14. The coal nozzle assembly according to claim 13 , wherein the catalyst comprises Lanthanum Strontium Titanate.

15. The coal nozzle assembly according to claim 1 , wherein a catalyst is applied to a cover plate of the nozzle tip.

16. A method comprising:
implementing a coal nozzle assembly in a steam generation apparatus, the coal nozzle assembly including:
an inner housing for conveying primary air and coal particles through a nozzle tip toward an exit face;
an outer housing for conveying secondary air through the nozzle tip,
at least one bar located in the inner housing near the exit face; and
a cover plate downstream of the at least one bar to prevent abrasion of the trailing edges of the at least one bar,
wherein the outer housing and the inner housing are arranged coaxially and limit a channel for the secondary air,
wherein the cross-sectional area (A IH ) of the inner housing increases towards an exit face of the nozzle tip,
wherein the cross-sectional area (A OH ) of the outer housing decreases towards the exit face; and

operating the coal nozzle assembly to convey the primary air and the coal particles through the inner housing toward the exit face and to convey the secondary air through the outer housing, wherein the operating includes:
decelerating the flow of the primary air and the coal particles;
subsequently accelerating the flow of primary air and the coal particles;
mixing the flow of primary air and the coal particles by inducing a stall when exiting the inner housing; and
enclosing the primary air and the coal particles by a perimeter flow of the secondary air.

17. A steam generating system, comprising:
a furnace; and
a coal nozzle assembly for directing a flow of solid particles entrained in a fluid into the furnace, wherein the coal nozzle assembly includes:
a nozzle tip;
an inner housing for conveying primary air and coal through the nozzle tip toward an exit face;
an outer housing for conveying secondary air through the nozzle tip,
at least one bar located in the inner housing near the exit face; and
a cover plate downstream of the at least one bar to prevent abrasion of the trailing edges of the at least one bar,
wherein the outer housing and the inner housing are arranged coaxially and limit a channel for the secondary air,
wherein the cross-sectional area (A IH ) of the inner housing increases towards an exit face of the nozzle tip, and
wherein the cross-sectional area (A OH ) of the outer housing decreases towards the exit face.

Assignees

• General Electric Technology Gmbh

Inventors

• Sapanaro Michael
• Vitse Frederic
• Ladue Rachel
• Krawiec Joseph

Classifications

• F23D2201/30

  Wear protection · CPC title

• F23D2201/10

  Nozzle tips · CPC title

• F23D2201/20

  Fuel flow guiding devices · CPC title

• F23D2900/00001

  local catalytic coatings applied to burner surfaces · CPC title

• F23D1/00 Primary

  Burners for combustion of pulverulent fuel · CPC title