System and method for increasing the concentration of pulverized fuel in a power plant
A pre-ignition conduit for a pulverized fuel nozzle includes a duct having first and second opposing end portions, the first end portion configured to face an outlet of an igniter. The conduit further includes a cone-shaped concentrator for collecting and forwarding pulverized fuel into the duct for ignition, the cone-shaped concentrator being secured to the first end portion and located between the outlet of the igniter and the duct. The pre-ignition conduit functions as an ignition chamber within a pulverized fuel nozzle.
1. A pre-ignition conduit for a pulverized fuel nozzle comprising:
a duct having first and second opposing end portions, the first end portion facing an outlet of an igniter;
a cone-shaped concentrator for collecting and forwarding pulverized fuel into the duct for ignition, the cone-shaped concentrator being secured to the first end portion and located between the outlet of the igniter and the duct, wherein the cone-shaped concentrator includes an eccentric cone; and
wherein the pre-ignition conduit functions as an ignition chamber within a pulverized fuel nozzle.
2. The pre-ignition conduit of claim 1 wherein the cone-shaped concentrator has a circumferential edge portion that includes a discontinuity.
3. The pre-ignition conduit of claim 1 wherein the cone-shaped concentrator is located at a distance of about 50 mm to about 150 mm from the igniter outlet.
4. The pre-ignition conduit of claim 1 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d; and
wherein if D>500 mm then d≥D/2.
5. The pre-ignition conduit of claim 1 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d; and
wherein if 500 mm≤D≤600 mm then 250 mm≤d≤300 mm.
6. The pre-ignition conduit of claim 1 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d; and
wherein if D>600 mm then d≤D/2.
7. The pre-ignition conduit of claim 1 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d and d≤2D/3.
8. The pre-ignition conduit of claim 1 wherein the duct of the pre-ignition conduit has an inner diameter d and the outlet of the igniter has an outer diameter P and d≥P.
9. The pre-ignition conduit of claim 1 wherein the pulverized fuel nozzle has an inner diameter D and pre-ignition conduit has an overall length L and L>D.
10. The pre-ignition conduit of claim 1 wherein the cone-shaped concentrator has a cone angle β that is between 5 and 45 degrees.
11. The pre-ignition conduit of claim 10 wherein the cone angle β is between 15 and 30 degrees.
12. The pre-ignition conduit of claim 1 wherein the cone-shaped concentrator has an inner diameter M and the duct of the pre-ignition conduit has an inner diameter d and d×1.1≤M≤d×1.3.
13. A pulverized fuel nozzle for a burner having an internal diameter D, the nozzle comprising:
an igniter having an outlet;
a pre-ignition conduit that includes a duct have first and second opposing end portions, the first end portion configured to face the outlet of the igniter and a cone-shaped concentrator for collecting and forwarding pulverized fuel into the duct for ignition wherein the cone-shaped concentrator includes an eccentric cone, the cone-shaped concentrator being secured to the first end portion and located between the outlet of the igniter and the duct; and
wherein the pre-ignition conduit functions as an ignition chamber within the pulverized fuel nozzle.
14. The pulverized fuel nozzle of claim 13 wherein the cone-shaped concentrator has a circumferential edge portion that is discontinuous.
15. The pulverized fuel nozzle of claim 13 wherein the cone-shaped concentrator is located at a distance of about 50 mm to about 150 mm from the igniter outlet.
16. The pulverized fuel nozzle of claim 13 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d; and
wherein if D>500 mm then d≥D/2.
17. The pulverized fuel nozzle of claim 13 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d; and
wherein if 500 mm ≤D≤600 mm then 250 mm≤d≤300 mm.
18. The pulverized fuel nozzle of claim 13 Therein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d; and
wherein if D>600 mm then d≤D/2.
19. The pulverized fuel nozzle of claim 13 wherein the pulverized fuel nozzle has an inner diameter D and the duct of the pre-ignition conduit has an inner diameter d and d≤2D/3.
20. The pulverized fuel nozzle of claim 13 wherein the duct of the pre-ignition conduit has an inner diameter d and the outlet of the igniter has an outer diameter P and d≥P.
21. The pulverized fuel nozzle of claim 13 wherein the pulverized fuel nozzle has an inner diameter D and pre-ignition conduit has an overall length L and L≥D.
22. The pulverized fuel nozzle of claim 13 wherein the cone-shaped concentrator has a cone angle β that is between 5 and 45 degrees.
23. The pulverized fuel nozzle of claim 22 wherein the cone angle β is between 15 and 30 degrees.
24. The pulverized fuel nozzle of claim 13 wherein the cone-shaped concentrator has an inner diameter M and the duct of the pre-ignition conduit has an inner diameter d and d×1.1≤M≤d×1.3.