PLASMA IGNITION BURNER
A plasma ignition burner. The plasma ignition burner has at least two stages of burner barrels and a plasma generator for igniting the pulverized coal in a first stage burner barrel of the at least two stages of burner barrels. The burning flame of the former stage burner barrel ignites the pulverized coal in the next stage burner barrel, or further burns with the supplemented air in the next stage burner barrel. The axial direction of said plasma generator is parallel to the direction along which the pulverized-coal-contained air flow enters into the first stage burner barrel and at the same time, parallel to the axis of the burner barrels.
The present invention relates to pulverized coal burning technical field, and particular to a plasma ignition burner.
BACKGROUND ARTCoal fired power generation is a main electricity generation manner adopted by different countries at present. Ignition is a main aspect of the burning process of the boiler. With the enlargement of the capacity of the boiler, how to accomplish the starting process of the boiler rapidly and economically becomes an important problem to be imminently solved.
Plasma ignition technology has been developed recently to replace the oil ignition manner which consumes a lot of burning oil.
In order to be able to ignite inferior coal, the conventional plasma igniting system adopts the so-called “precombustion chamber” technology. The precombustion chamber is constructed to keep the temperature of the burner barrel, normally by attaching a layer of fire-resistant material to the internal of the firebox. The chamber wall of the precombustion chamber has very high temperature through initial heating, which aids in (even independently) igniting the fuel. The precombustion chamber is long (about 2 meters) and through the action of the plasma, gasifies the pulverized coal in the pulverized-coal-contained air flow entering into the precombustion chamber, thereby generating a lot of burnable gas, mainly CO et al. And then, the thermal energy released when the burnable gas burns is used to ignite the succeeding pulverized coal. This is also a hierarchical ignition manner, but since the temperature in the precombustion chamber is too high, the pulverized coal easily clinkers inside and therefore can not be used further.
In order to overcome the above problem, a new structure of hierarchical burner barrel has been proposed. As shown in
In the above technology, the plasma generator is inserted along the axial direction of the burner barrels and the pulverized-coal-contained air flow inlet and the air flow are both arranged to be perpendicular to the axis of the burner barrels. That is, the direction of the plasma flame is perpendicular to the direction of the air flow entering into the first stage burner barrel. Therefore, it is necessary to add guide plate (not shown) to deflect the air flow to be parallel. Similarly, the direction along which the second stage pulverized coal enters into the second stage burner barrel is also perpendicular to the direction of the flame injected from the first stage burner barrel, so it is also necessary to add guide plate to make the directions to be parallel. However, the guide plate can not deflect the air flow completely due to the limitation of the space. Since the two air flows can not be absolutely parallel, the entering air flow will blow the plasma flame (or the former stage flame) deflected, which causes the temperature of the barrel wall increasing and the pulverized coal clinkering.
In addition, in this technology, because the pulverized-coal-contained air flow and the air flow both enters in the direction perpendicular to the burner barrels, on the section plane perpendicular to the burner barrels, the concentration of the pulverized coal and the velocity of the air flow, et al. are not uniform, thereby affecting the burning quality.
Afterward, in order to make it easy to arrange on the spot, a plasma ignition burner constructed as shown in
Therefore, a new technology is needed to further prevent the pulverized coal from clinkering on the wall of the burner barrels.
SUMMARY OF THE INVENTIONTherefore, an object of the present invention is to provide a plasma generator which can relieve the problem of clinkering. It can be seen from the above description of the prior art, the fact that there exists an angle between the inserting direction of the plasma generator (that is, the direction of the plasma flame) and the direction of the pulverized-coal-contained air flow is a reason of the clinkering problem. Therefore, with respect to the above object, the gist of the present invention is to rearrange the pulverized-coal-contained air flow inlet and the plasma generator, so as to make the direction along which the pulverized-coal-contained air flow enters into the first stage burner barrel consistent with the direction of the plasma flame.
In addition, in order to further solve the problem of clinkering, it is necessary to make the pulverized-coal-contained air flow or air flow of the next stage as consistent with the pulverized coal flame of the former stage as possible.
For this purpose, the present invention provides a plasma ignition burner, comprises at least two stages of burner barrels and a plasma generator for igniting the pulverized coal in a first stage burner barrel of said at least two stages of burner barrels, wherein the burning flame of the former stage burner barrel ignites the pulverized coal in the next stage burner barrel, or further burns with the supplemented air in the next stage burner barrel, characterized in that the axial direction of said plasma generator is parallel to the direction along which the pulverized-coal-contained air flow enters into the first stage burner barrel and at the same time, parallel to the axis of the burner barrels.
The present invention will be described in details with reference to the accompanying drawings. In the drawings, the same reference sighs are used for the same or corresponding technical features.
The key of the present invention is to make the insertion direction of the plasma generator 302 parallel to the direction along which the pulverized-coal-contained air flow enters into the first stage burner barrel 104 and at the same time, parallel to the axis of the burner barrels. Thus, the pulverized-coal-contained air flow enters into the burner barrels parallel to the axis of the burner barrels, without distribution asymmetry of the pulverized coal on the section plane of the burner barrels due to the inertia of the pulverized-coal-contained air flow. Moreover, since the injection direction of the plasma flame of the plasma generator is consistent with the direction along which the pulverized-coal-contained air flow enters into the burner barrels, the plasma flame will not be blown defected to the wall of the burner barrels. The above two points effectively alleviate the problem of clinkering on the wall of the burner barrels.
In the first embodiment shown in
As shown in
Compared with the burner inserted along the radial direction in
In the first embodiment as described above, the concentrating of the pulverized coal in the central barrel of the burner depends on the concentrating action of the guide plate 306 in the bending tube 308. However, due to the limitation of the space, the concentration in the central barrel can not be increased without limitation, which affects the effect of ignition. For this purpose, the second embodiment according to the present invention as shown in
To be concise,
In this embodiment, the pipe for supplying the pulverized-coal-contained air flow branches into two pipes, that is, primary pipe 508 and branch pipe 502. The primary pipe 508 may be connected to the burner internal barrel 202 in a conventional way or by adopting the bending tube 308 in the first embodiment. At the same time, the central barrel 510 is guided from the first stage burner barrel 104 to be connected to the branch pipe 502. Similarly, the connection between the branch pipe 502 and the central barrel 510 may adopt the conventional way or a second bending tube 512 similar to the bending tube 308 in the first embodiment and wherein, the guide plate 306 (not shown in
In this way, the concentration of the pulverized coal entering into the central barrel and further entering into the first stage burner barrel may be made relatively high by directly guiding the pulverized-coal-contained air flow into the central barrel using the branch tube, so as to aid in the ignition. As a preferred embodiment, it is necessary to adjust the amount of the entering pulverized-coal-contained air flow, and/or increase the concentration of the pulverized coal in the pulverized-coal-contained air flow entering into the plasma ignition burner as high as possible. For this purpose, an adjuster may be arranged on the branching point of the primary pipe and the branch pipe for flexibly adjusting the amount of the pulverized coal entering into the branch tube.
As a variation of the above-described solution, if there are three or more stages of burner barrels guiding the pulverized-coal-contained air flow in the burner, the respective stages of burner barrels may be distributed between the central barrel and the burner internal barrel. For example, if there are three stages of burner barrels, the pulverized coal in the first stage burner barrel and the second stage burner barrel of the plasma ignition burner may be guided in simultaneously through the central barrel and the branch pipe (in this case, the central barrel and the internal structure thereof is similar to that shown in
In a preferred embodiment, a valve 504 may be provided in the branch pipe, which is turned on in the starting ignition stage and the low-load stable combustion stage of the burner and turned off after the ignition is completed and the combustion of the burner becomes stable. This valve 504 may also be designed to be incorporated with the adjuster 506, so that the adjuster serves as an adjuster and a branch tube valve simultaneously.
It can be seen from the above description of the second embodiment, the gist of this embodiment is to increase the concentration of the pulverized coal in the first stage burner barrel by using the branch tube. It is neither limited to ignite using the plasma generator, nor limited to provide the plasma generator along the axial direction of the burner barrels. Therefore, the detail of various aspects of the second embodiment can be either combined or not combined with those of the first embodiment. Specifically, the ignition device may be oil gun besides the plasma generator and the arrangement manner thereof can be insertion along any direction besides axial insertion, including radial insertion and slanting insertion.
In the above-described solutions, since the branch tube is arranged and the adjustor is attached, the flowing velocity of the pulverized-coal-contained air flow and the concentration of the pulverized coal in the central barrel of the burner can be independently adjusted, so that the optimum ignition working condition can be achieved.
In addition, for those old type burners which have been amounted on the spot, a convenient and low-cost reconstructing means can be provided by using the above-described second embodiment, so that the present invention can be applied.
For example, the whirling type pulverized coal burner adopted by many burning coal firepower electricity generator has a central barrel and the mixture of the pulverized coal and the air is sent into the hearth from the external of the central barrel. For example, LNASB axial swirl pulverized coal burner (refer to
The above-described reconstruction manner forms a third-stage burner (that is, the first stage burner barrel, the central barrel and the external barrel). In fact, if possible, a two-stage burner may be formed only by the central barrel and the external barrel, without the first stage burner barrel added. In addition, more stages of burner barrel may be added in the central barrel, or more stages of burner barrel may be added in the external barrel.
In addition, the ignition device may be any kind of ignition device either in the original burner, or in the reconstructed burner, including oil gun and plasma ignition device, et al.
The preferred embodiments of the present invention are described with reference to the accompanying drawings in the above. Apparently, the present invention is not limited to the specific details as described above and various changes or substitutions can be made, which also falls within the protection scope of the present invention.
Claims
1. A plasma ignition burner, comprising at least two stages of burner barrels and a plasma generator for igniting the pulverized coal in a first stage burner barrel of said at least two stages of burner barrels, wherein the burning flame of the former stage burner barrel ignites the pulverized coal in the next stage burner barrel, or further burns with the supplemented air in the next stage burner barrel, wherein the axial direction of said plasma generator is parallel to the direction along which the pulverized-coal-contained air flow enters into the first stage burner barrel and at the same time, parallel to the axis of the burner barrels.
2. The plasma ignition burner according to claim 1, further comprising a bending tube for guiding the pulverized-coal-contained air flow into said at least two stages of burner barrels, wherein one end of the bending tube on the side of the burner barrels is parallel to the axis of the burner barrels, and said plasma generator is inserted into the first stage burner barrel through the wall of said bending tube along the axial direction of the burner barrels.
3. The plasma ignition burner according to claim 2, further comprising a guide plate arranged along the axis of the bending tube, wherein one end of the guide plate on the side of the burner barrels is parallel to the axis of the plasma generator.
4. The plasma ignition burner according to claim 3, wherein said guide plate extends to the vicinity of the inlet of the first stage burner barrel.
5. The plasma ignition burner according to claim 4, wherein the ends of said plasma generator and said guide plate are arranged on the axis of the burner barrels, or deflected form the axis of the burner barrels for a predetermined distance.
6. The plasma ignition burner according to claim 3, wherein the shape of the section plane of said guide plate is planar.
7. The plasma ignition burner according to claim 3, wherein the shape of the section plane of said guide is bending surface.
8. The plasma ignition burner according to claim 2, wherein an anti-abrasion protecting sleeve is provided to protect said plasma generator.
9. The plasma ignition burner according to claim 8, wherein the windward surface of said anti-abrasion protecting sleeve is V-shaped.
Type: Application
Filed: Jul 18, 2008
Publication Date: Feb 12, 2009
Inventors: Peng LIU (Shandong), Xiaoyong ZHANG (Shandong), Yingjie QIAN (Shandong), Xinguang WANG (Shandong), Wenbo YU (Shandong), Fei CAI (Shandong), Yuwang MIAO (Shandong), Tao NIU (Shandong), Yupeng WANG (Shandong)
Application Number: 12/175,963
International Classification: F23D 1/00 (20060101);