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A burner includes a first oxidant conduit to transmit a first stream of an oxidant; a solid fuel conduit having an outtake and surrounding the first oxidant conduit, thereby forming a first annulus to transmit a mixture of a transport gas and particles of a solid fuel; a second oxidant conduit surro

A burner includes a first oxidant conduit to transmit a first stream of an oxidant; a solid fuel conduit having an outtake and surrounding the first oxidant conduit, thereby forming a first annulus to transmit a mixture of a transport gas and particles of a solid fuel; a second oxidant conduit surrounding the solid fuel conduit, thereby forming a second annulus to transmit a second stream of the oxidant or an other oxidant; and means for segregating the mixture proximate the outtake into a lean fraction stream and a dense fraction stream. The first stream of the oxidant exiting the first oxidant conduit combines during combustion with the lean fraction stream, thereby forming an inner combustion zone adjacent the outtake, and the second stream of the oxidant, or the other oxidant, exiting the second oxidant conduit combines during combustion with the dense fraction stream, thereby forming an outer combustion zone.

대표청구항 ▼

The invention claimed is: 1. A burner for combusting a solid fuel, comprising: a first oxidant conduit having a first longitudinal axis, a first oxidant inlet, and a first oxidant outlet, the first oxidant conduit adapted to transmit a first stream of an oxidant, the oxidant having an oxygen concen

The invention claimed is: 1. A burner for combusting a solid fuel, comprising: a first oxidant conduit having a first longitudinal axis, a first oxidant inlet, and a first oxidant outlet, the first oxidant conduit adapted to transmit a first stream of an oxidant, the oxidant having an oxygen concentration greater than 21 vol. %; a solid fuel conduit having a second longitudinal axis substantially parallel to the first longitudinal axis, a solid fuel conduit intake, and a solid fuel conduit outtake, the solid fuel conduit surrounding the first oxidant conduit and thereby forming a first annulus between the first oxidant conduit and the solid fuel conduit, the first annulus adapted to transmit a mixture of a transport gas and a plurality of particles of the solid fuel; a second oxidant conduit having a third longitudinal axis substantially parallel the second longitudinal axis, a second oxidant inlet, and a second oxidant outlet, the second oxidant conduit positioned adjacent to and surrounding the solid fuel conduit and thereby forming a second annulus between the solid fuel conduit and the second oxidant conduit, the second annulus adapted to transmit a second stream of the oxidant or another oxidant having an oxygen concentration greater than 21 vol. %; a solid fuel stratifier positioned in the first annulus; wherein the solid fuel stratifier segregates the mixture proximate to the solid fuel conduit outtake into a lean fraction stream of the mixture adjacent the first oxidant conduit and a dense faction stream of the mixture adjacent to the solid fuel conduit, the dense fraction stream containing a first mass ratio of the transport gas to the solid fuel, and the lean fraction stream containing a second mass ratio of the transport gas to the solid fuel, the second mass ratio being greater than the first mass ratio; and a separator comprising an inner wall and an outer wall, the separator positioned in the first annulus and between the solid fuel stratifier and the solid fuel conduit outtake wherein the separator surrounds a portion of the first oxidant conduit and is surrounded by the solid fuel conduit thereby forming a first subsidiary annulus between the first oxidant conduit and the inner wall of the separator and a second subsidiary annulus between the outer wall of the separator and the solid fuel conduit, and wherein the separator maintains the lean fraction stream and the dense fraction stream as two distinct streams, wherein at least a portion of the first stream of the oxidant exiting the first oxidant outlet combines during combustion with at least a portion of the lean fraction stream, thereby forming an inner combustion zone adjacent the solid fuel conduit outtake, the inner combustion zone having a first radius and a first length extending outwardly from the solid fuel outtake, and wherein at least a portion of the second stream of the oxidant or the other oxidant exiting the second oxidant outlet combines during combustion with at least a portion of the dense fraction stream, thereby forming an outer combustion zone near the inner combustion zone, the outer combustion zone having a second radius and a second length extending outwardly from the solid fuel outtake, the second radius being greater than the first radius and the second length being greater than the first length. 2. The burner of claim 1, further comprising: an auxiliary gas conduit having a fourth longitudinal axis substantially parallel the third longitudinal axis, an auxiliary gas inlet, and an auxiliary gas outlet spaced apart from the auxiliary gas inlet, the auxiliary gas conduit surrounding the second oxidant conduit and thereby forming a third annulus between the second oxidant conduit and the auxiliary gas conduit, the third annulus adapted to transmit a stream of an auxiliary gas entering the auxiliary gas inlet and exiting the auxiliary gas outlet. 3. The burner of claim 1, further comprising a swirl generator disposed in the first oxidant conduit. 4. The burner of claim 1, wherein the solid fuel stratifier comprises a swirl generator and the separator comprises a vortex finder. 5. The burner of claim 4, wherein the vortex finder and the swirl generator are adjustable such that the segregation of the mixture is adjusted by either increasing or decreasing at least one of a hydraulic radius of the vortex finder and a distance from the swirl generator to the vortex finder. 6. The burner of claim 4, wherein the vortex finder has either swirl vanes or straightening vanes adapted to contact at least one of the lean fraction stream and the dense fraction stream. 7. The burner of claim 4, wherein the solid fuel conduit outtake and a portion of the vortex finder proximate the solid fuel conduit outtake form a nozzle tip profile, and the nozzle tip profile is modified by at least one of an outward divergence of the solid fuel conduit outtake and an inward convergence of the portion of the vortex finder proximate the solid fuel conduit outtake. 8. The burner of claim 1, wherein the first oxidant conduit and the solid fuel conduit are substantially co-axial. 9. The burner of claim 1, wherein at least two of the first oxidant conduit, the solid fuel conduit, and the second oxidant conduit are co-axial. 10. The burner of claim 1, wherein the first oxidant conduit and the solid fuel conduit extend such that the outlet of the first oxidant conduit and the outtake of the solid fuel conduit lie essentially in a single plane, wherein the plane is perpendicular to the longitudinal axes of both the first oxidant conduit and the solid fuel conduit. 11. A method for combusting a solid fuel, comprising the steps of: providing a first oxidant conduit having a first longitudinal axis, a first oxidant inlet, and a first oxidant outlet; transmitting through the first oxidant conduit a first stream of an oxidant having an oxygen concentration greater than 21% vol.; providing a solid fuel conduit having a second longitudinal axis substantially parallel to the first longitudinal axis, a solid fuel conduit intake, and a solid fuel conduit outtake, the solid fuel conduit surrounding the first oxidant conduit and thereby forming a first annulus between the first oxidant conduit and the solid fuel conduit; transmitting through the first annulus a mixture of a transport gas and a plurality of particles of the solid fuel; providing a second oxidant conduit having a third longitudinal axis substantially parallel to the second longitudinal axis, a second oxidant inlet, and a second oxidant outlet, the second oxidant conduit positioned adjacent to and surrounding the solid fuel conduit and thereby forming a second annulus between the solid fuel conduit and the second oxidant conduit; transmitting through the second annulus a second stream of the oxidant or another oxidant having an oxygen concentration greater than 21% vol.; segregating the mixture proximate the solid fuel conduit outtake into a lean fraction stream of the mixture adjacent the first oxidant conduit and a dense fraction stream of the mixture adjacent the solid fuel conduit, the dense fraction stream containing a first mass ratio of the transport gas to the solid fuel, and the lean fraction stream containing a second mass ratio of the transport gas to the solid fuel, the second mass ratio being greater than the first mass ratio; maintaining the lean fraction stream and the dense fraction stream as two distinct streams with a separator comprising an inner wall and an outer wall, the separator positioned in the first annulus proximate to the solid fuel conduit outtake, wherein the separator surrounds a portion of the first oxidant conduit and is surrounded by the solid fuel conduit thereby forming a first subsidiary annulus between the first oxidant conduit and the inner wall of the separator and a second subsidiary annulus between the outer wall of the separator and the solid fuel conduit; combusting at least a portion of the first stream of the oxidant with at least a portion of the lean fraction stream, thereby forming an inner combustion zone adjacent the solid fuel conduit outtake, the inner combustion zone having a first radius and a first length extending outwardly from the solid fuel outtake; and combusting at least a portion of the second stream of the oxidant or the other oxidant with at least a portion of the dense fraction stream, thereby forming an outer combustion zone near the inner combustion zone, the outer combustion zone having a second radius and a second length extending outwardly from the solid fuel outtake, the second radius being greater than the first radius and the second length being greater than the first length, wherein the combusting of the at least a portion of the lean fraction stream in the inner combustion zone contributes to the ignition and stabilization of the combustion of the dense fraction stream in the outer combustion zone. 12. The method of claim 11, comprising the further steps of: providing an auxiliary gas conduit having a fourth longitudinal axis substantially parallel the third longitudinal axis, an auxiliary gas inlet, and an auxiliary gas outlet spaced apart from the auxiliary gas inlet, the auxiliary gas conduit surrounding the second oxidant conduit and thereby forming a third annulus between the second oxidant conduit and the auxiliary gas oxidant conduit; transmitting through the third annulus a stream of an auxiliary gas entering the auxiliary gas inlet and exiting the auxiliary gas outlet. 13. The method of claim 11, further comprising providing a swirl generator in the first oxidant conduit. 14. The method of claim 11, further comprising providing a swirl generator in the first annulus proximate the solid fuel conduit outtake, and providing a vortex finder in the first annulus at a distance from the swirl generator at a location between the swirl generator and the solid fuel conduit outtake. 15. The method of claim 14, wherein segregation of the mixture is adjusted by either increasing or decreasing at least one of a hydraulic radius of the vortex finder and a distance from the swirl generator to the vortex finder. 16. The method of claim 14, wherein the vortex finder has either swirl vanes or straightening vanes adapted to contact at least one of the lean fraction stream and the dense fraction stream. 17. The method of claim 14, wherein the solid fuel conduit outtake and a portion of the vortex finder proximate the solid fuel conduit outtake form a nozzle tip profile, and the nozzle tip profile is modified by at least one of an outward divergence of the solid fuel conduit outtake and an inward convergence of the portion of the vortex finder proximate the solid fuel conduit outtake. 18. The method of claim 11, wherein the rate of transmission of at least one of the first stream of the oxidant and the second stream of the oxidant or another oxidant having an oxygen concentration greater than 21 vol. % is variable. 19. The method of claim 11, wherein the first oxidant conduit and the solid fuel conduit are substantially co-axial. 20. The method of claim 11, wherein at least two of the first oxidant conduit, the solid fuel conduit, and the second oxidant conduit are co-axial. 21. The method of claim 11, wherein the first oxidant conduit and the solid fuel conduit extend such that the outlet of the first oxidant conduit and the outtake of the solid fuel conduit lie essentially in a single plane, wherein the plane is perpendicular to the longitudinal axes of both the first oxidant conduit and the solid fuel conduit, and wherein a portion of the first stream of the oxidant initially contacts a portion of the lean fraction stream of the mixture at about the single plane.