JP2013024425A - Burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burner which prevents the burner from being thermally damaged and achieves stable gasification operation by suppressing thermal elongation and deformation of a cooling water pipe.SOLUTION: In the burner, which includes: a cylindrical fuel nozzle 5 for jetting pulverized coal 3 conveyed by carrier gas and a cylindrical oxidant supply pipe 7 disposed coaxially with the cylindrical fuel nozzle 5, a groove 13 for mounting a cooling water pipe 9 rolling along an outer peripheral wall is formed on the other outer peripheral wall enclosing either of the cylindrical fuel nozzle 5 or cylindrical oxidant supply pipe 7.

Description

  The present invention relates to a burner, and more particularly to a structure of a burner that supplies a solid material such as coal and an oxidizing gas into a gasifier.

  As a method of gasifying coal, solid fuel pulverized coal and oxidant gas are supplied from a burner into a gasification furnace maintained at a high temperature, and carbon monoxide and hydrogen are produced by burning combustible components in the fuel. There is known an air-bed coal gasification method in which ash is generated and converted into slag containing no harmful components and recovered. According to this method, fuel gas can be obtained with high efficiency, environmental conservation is excellent, and there are many applicable raw material types. Therefore, there are many types of coal gasification combined power generation systems, coal gasification combined fuel cell combined power generation systems, etc. It is expected to be used in a hydrogen production system used for generation thermal power generation systems, coal liquefaction, chemical raw materials and the like.

  A gasification furnace used in this type of gasification plant is provided with a burner for injecting pulverized coal. This burner is generally inserted from the outside of the furnace through a through hole in the furnace wall, and is attached with its tip protruding into the furnace.

  By the way, the tip of the burner inserted into the furnace is not only exposed to a high temperature equal to or higher than the melting temperature of ash, but may be subjected to a large heat load due to adhesion, separation, etc. of molten slag. Thus, when the tip of the burner is subjected to a large heat load, cracks due to thermal fatigue, thinning due to sulfide corrosion, etc. occur, and the life of the burner is significantly reduced. For this reason, this type of burner has a multi-tube structure in which the outer periphery of the fuel nozzle is surrounded by a cylindrical oxidant supply pipe and the outer periphery of the oxidant supply pipe is further surrounded by a cooling water pipe through which cooling water flows. Generally adopted.

  Separately, a burner structure is disclosed in which at least an outer peripheral portion of a cylindrical oxidant supply pipe exposed in the furnace is spirally wound with a small-diameter cooling water pipe (see Patent Document 1). That is, since the cooling water flowing through the cooling water pipe can ensure a uniform and sufficient flow velocity with respect to the inner surface of the cooling water pipe with a relatively small amount of water, the tip portion of the burner can be efficiently cooled. Further, the burner is stretched and deformed to some extent in the longitudinal direction under the influence of heat in the furnace. However, according to the structure of Patent Document 1, not only the heat elongation deformation is suppressed by the cooling effect of the cooling water pipe, but also the furnace The thermal expansion deformation is absorbed by the seal expansion structure provided outside.

Japanese Patent Laid-Open No. 10-281414

  However, in patent document 1, since consideration is not given to the thermal expansion deformation of the cooling water pipe wound around the outer periphery of the oxidant supply pipe, when the cooling water pipe is exposed to a high temperature and subjected to fluctuations in heat load, the oxidant There is a risk of causing thermal elongation deformation in the longitudinal direction with respect to the supply pipe.

  The cooling water pipe extends from the outside of the furnace through the furnace wall toward the front end side of the oxidant supply pipe, extends the cooling water supply pipe, and then the cooling water pipe communicated with the cooling water supply pipe It is wound around the outer peripheral surface spirally from the tip end side of the supply pipe. For this reason, the thermal expansion deformation of the oxidant supply pipe is suppressed by the cooling effect of the cooling water flowing spirally through the cooling water pipe, but the cooling water pipe wound around the oxidant supply pipe is in the longitudinal direction of the oxidant supply pipe. Therefore, it is easy to cause thermal elongation deformation. For example, when the heat load applied to the tip of the burner fluctuates due to fluctuations in furnace temperature, adhesion of molten slag, repeated peeling, etc., the cooling water pipe undergoes thermal elongation deformation in the longitudinal direction of the burner, resulting in a high temperature The tip of the burner that protrudes into the furnace and becomes insufficiently cooled may be thermally damaged.

  In addition, when the jet flow from the burner is deflected by the cooling water pipe deformed in this way, the molten slag is likely to adhere to the tip of the burner, and the adhered molten slag grows to stabilize the gasifier. There is a risk of hindering operations. Further, the cooling water pipe is in spiral contact with the outer peripheral surface of the oxidant supply pipe, and a sufficient contact area between the cooling water pipe and the burner cannot be secured, so there is room for improvement in terms of cooling efficiency.

  An object of the present invention is to provide a burner capable of preventing thermal damage at the tip of the burner by suppressing the thermal elongation deformation of the cooling water pipe and performing a stable gasification operation.

  In order to solve the above problems, a burner according to the present invention comprises a cylindrical fuel nozzle that ejects a pulverized fuel conveyed by a carrier gas, and a cylindrical oxidant supply pipe that is provided coaxially with the fuel nozzle. And a groove for mounting a cooling water pipe wound around the outer peripheral wall is formed in the other outer peripheral wall surrounding one of the fuel nozzle and the oxidant supply pipe.

  According to this, since the cooling water pipe is wound in a state of being mounted in the groove, the thermal expansion deformation in the longitudinal direction of the burner is restrained by the groove. Therefore, even when the thermal load received by the tip of the burner fluctuates due to fluctuations in the furnace temperature, etc., the cooling water pipe does not protrude into the furnace against the outer peripheral wall, and the tip of the burner is removed from the high heat load in the furnace. Can be protected. In addition, since the deflection of the jet flow from the burner is restrained by restraining the thermal expansion deformation of the cooling water pipe, it is possible to prevent the molten slag from adhering to and growing on the tip of the burner. Stable operation is possible. Furthermore, by forming the groove, the contact area between the cooling water pipe and the outer peripheral wall can be increased, and heat transfer is promoted by the fin effect of the groove, so that the cooling efficiency of the burner can be increased.

  In this case, the groove is formed in a spiral shape along the outer peripheral wall. Moreover, a groove shall be formed from the front end side of the outer peripheral wall where winding of a cooling water pipe is started. If it does in this way, since the tip part of a burner can be efficiently cooled with a cooling water pipe, thermal damage of the tip part can be prevented.

  Moreover, it is preferable that the groove | channel has the groove depth more than the radius of a cooling water pipe. In this way, the maximum contact area between the cooling water pipe and the outer peripheral wall can be ensured, and the fin effect of the groove can be increased, so that the cooling efficiency of the burner can be further increased.

  In addition, in the tip of the fuel nozzle and the tip of the oxidant supply pipe, the annular channel formed between one outer peripheral surface and the other inner peripheral surface is a gas ejected from this channel, Suppose that it forms so that it may go to the axial center direction of one outer peripheral surface. In this way, the contact efficiency between the pulverized coal ejected into the furnace by the carrier gas and the oxidant gas is increased, and the pulverized coal and the oxidant gas react efficiently, thereby improving the gasification efficiency. it can.

  In addition, when there is a gap between the burner and the through hole in the furnace wall, the cooling water pipe wound from the front end side of the outer peripheral wall is wound with at least the first round being overlapped in the circumferential direction. It is preferable to be made. Thus, by winding the cooling water pipe twice, the gap between the burner and the through hole in the furnace wall can be reduced, thereby preventing the slag from adhering and growing from this gap. it can. Therefore, the cooling efficiency on the tip side of the burner can be increased, and thermal damage to the tip portion of the burner can be reliably prevented. Here, the inner winding tube and the outer winding tube of the cooling water pipe wound twice and the inner winding tube and the outer peripheral wall are welded and fixed, respectively. In this way, since the free movement of the inner and outer tubes in the longitudinal direction of the burner can be restricted, the burner can be prevented from being damaged by heat.

  A cylindrical partition wall is provided between one outer peripheral surface of the fuel nozzle and the oxidant supply pipe and the other inner peripheral surface, and an oxidant gas flows between the inner peripheral surface of the partition wall and the one outer peripheral surface. A space through which a gas that does not contain oxygen flows is formed between the outer peripheral surface of the partition wall and the other inner peripheral surface. By doing so, the tip portion of the burner can be effectively cooled by ejecting the gas, so that the temperature fluctuation of the tip portion can be kept low. Moreover, since the adhesion and growth of the molten slag to the tip portion of the burner can be suppressed by the blowing effect by the gas, thermal damage or the like of the tip portion of the burner can be prevented. Furthermore, since a cylindrical curtain made of gas is formed by ejecting a gas not containing oxygen to the outside of the oxidant gas ejected into the furnace, contact between the combustible gas and the oxidant gas in the furnace Can be suppressed. As a result, since the generation of a high temperature field due to the reaction of the combustible gas and the oxidant gas in the vicinity of the tip of the burner can be prevented, thermal damage to the tip of the burner can be prevented. Here, as the gas not containing oxygen, nitrogen, water vapor, a part of the generated gas generated in the gasification furnace, or the like can be used.

  According to the present invention, even when the heat load in the furnace fluctuates, the thermal expansion deformation of the cooling water pipe can be suppressed. Moreover, according to the present invention, since the cooling efficiency of the burner is increased, thermal damage to the burner tip can be prevented, and a stable gasification operation can be performed.

It is a figure which shows the structure of 1st Embodiment of the burner to which this invention is applied. It is a figure which shows the structure of 2nd Embodiment of the burner to which this invention is applied. It is a figure which shows the structure of 3rd Embodiment of the burner to which this invention is applied. It is a figure which shows the structure of 4th Embodiment of the burner to which this invention is applied.

(First embodiment)
Hereinafter, a first embodiment of a burner to which the present invention is applied will be described with reference to FIG. Although the burner of this embodiment is described as being provided on the furnace wall of a gasification furnace that gasifies pulverized coal, the burner is limited to this example as long as it is a gasification burner that ejects fuel and oxidant gas. is not.

  The burner 1 of the present embodiment is inserted into a through-hole of a furnace wall of a gasifier (not shown), and is attached to the furnace wall in a state in which the tip side protrudes from the furnace wall to the inside of the furnace. As shown in FIG. 1, this burner has a cylindrical fuel nozzle 5 that ejects pulverized coal 3 that is carried along with a carrier gas such as nitrogen gas from the center, and a coaxial outer periphery of the fuel nozzle 5. A cylindrical oxidant supply pipe 7 provided in an enclosed manner and a small-diameter cooling water pipe 9 attached to the outer peripheral surface of the oxidant supply pipe 7 are configured. An annular channel is formed between the outer peripheral surface of the fuel nozzle 5 and the inner peripheral surface of the oxidant supply pipe 7 through which an oxidant gas 11 such as oxygen or air flows.

  On the outer peripheral surface of the oxidant supply pipe 7, a groove 13 in which the cooling water pipe 9 is mounted is formed in a spiral shape in the longitudinal direction. The groove 13 has a semicircular cross section, and a cooling water pipe 9 having a circular cross section is fitted into the groove. The cooling water pipe 9 extends from the outside of the furnace through the furnace wall and extends the cooling water supply pipe 15 toward the tip side of the oxidant supply pipe 7 in the furnace, and then bends the cooling water supply pipe 15. The oxidant supply pipe 7 is attached to the groove 13 from the front end side, and is wound around the groove 13 so as to surround the oxidant supply pipe 7 in a spiral shape. Thereby, the cooling water 17 supplied from the outside of the furnace via the cooling water supply pipe 15 passes through the cooling water pipe 9 wound around the oxidant supply pipe 7 in a spiral shape, and is returned to the outside of the furnace.

  According to this embodiment, since the cooling water pipe 9 is wound along the groove 13, the thermal elongation deformation in the longitudinal direction of the burner 1 is restrained to some extent by the groove 13. Therefore, even when the thermal load received from the inside of the furnace by the tip of the burner 1 fluctuates due to fluctuations in furnace temperature, adhesion of molten slag, repeated peeling, etc., the cooling water pipe 9 is independent of the oxidant supply pipe 7. Will not be deformed and protrude into the high-temperature furnace. Therefore, the front-end | tip part of the burner 1 can be reliably protected from the high heat load in a furnace. Further, since the thermal expansion deformation of the cooling water pipe 9 is restricted in the longitudinal direction, the jet flow from the burner 1 is not deflected. For this reason, it can prevent that molten slag adheres to the front-end | tip part of the burner 1, and grows, and the stable operation of a gasification furnace is attained. Furthermore, since the groove 13 is formed in accordance with the shape of the cooling water pipe 9, the maximum contact area between the cooling water pipe 9 and the outer peripheral wall of the oxidant supply pipe 7 is ensured, and heat transfer is performed by the fin effect of the groove 13. Therefore, the cooling efficiency of the burner 1 can be increased.

  The groove 13 of the present embodiment is formed so that the interval between adjacent grooves 13 is constant when viewed from the cross-sectional direction, but is not limited to this, for example, the longitudinal direction inside the furnace It is also possible to set the groove interval of the predetermined region to be relatively short and to set the groove interval on the outside of the furnace to be relatively long, or to sequentially increase the groove interval from the inside of the furnace to the outside of the furnace. is there.

  Moreover, although the groove | channel 13 of this embodiment is set to the groove depth about the radius of the cooling water pipe 9, it is preferable to be set to the groove depth more than the radius of the cooling water pipe 9 at least. By setting in this way, the maximum contact area between the cooling water pipe 9 and the outer peripheral wall of the oxidant supply pipe 7 can be ensured, and the fin effect of the groove 13 can be enhanced. It can be increased and thermal damage can be prevented more reliably.

(Second Embodiment)
Next, a second embodiment of the burner to which the present invention is applied will be described with reference to FIG. In the present embodiment, a configuration different from that of the first embodiment will be described, and the same configuration as that of the first embodiment will be denoted by the same reference numeral and description thereof will be omitted.

  In the burner 21 of the present embodiment, an annular space formed in a gap between the outer peripheral surface of the front end portion of the fuel nozzle 5 and the inner peripheral surface of the front end portion of the oxidant supply pipe 7 is in the axial direction of the fuel nozzle 5. This is different from the first embodiment in that it is formed at a predetermined angle. That is, the outer peripheral surface of the tip portion of the fuel nozzle 5 is formed as a conical inclined surface 23 whose diameter decreases toward the tip side, and the inner peripheral surface of the tip portion of the oxidant supply pipe 7 is this conical shape. It is formed by forming a tapered inclined surface 25 facing the inclined surface with a certain distance. Therefore, the oxidant gas 11 is ejected in a cylindrical shape toward the axial direction of the fuel nozzle 5. With such a structure, the contact efficiency between the pulverized coal 3 ejected into the furnace and the oxidant gas 11 is increased, so that the pulverized coal 3 and the oxidant gas 11 efficiently react to increase gasification efficiency. be able to.

  Further, in this embodiment, since the inner peripheral surface of the tip portion of the oxidant supply pipe 7 is the inclined surface 25, the outer peripheral surface on the back side thereof is a conical inclined surface whose diameter is reduced toward the tip side. 27. Here, when the groove 13 is to be formed at the tip portion of the burner 21, it is extremely difficult to form a complete groove 13 at the tip portion having a complicated shape as in this embodiment. Therefore, as shown in FIG. 2, the groove 13 formed at the foremost end has a shape in which about half of the tip end side is opened with an inclined surface 27. The cooling water pipe 9 a mounted in such a groove 13 has a weak restraining force with respect to the longitudinal end side of the burner 21.

  On the other hand, in this embodiment, the cooling water pipe 9a and the inclined surface 27 at the most distal end portion of the burner 21 are fixed to each other by the welding fixing portion 29. In this way, as with the burner 1 of the first embodiment, the thermal expansion deformation of the cooling water pipe 9 in the longitudinal direction can be restricted to some extent, so that the cooling water pipe 9a is deformed independently with respect to the oxidant supply pipe 7. Can be suppressed. Thereby, since the heat | fever elongation deformation of the cooling water pipe 9 can be suppressed, the front-end | tip part of the burner 21 can be protected from the high heat load in a furnace, and stable operation can be implement | achieved while suppressing heat damage.

(Third embodiment)
Next, a third embodiment of the burner to which the present invention is applied will be described with reference to FIG. In this embodiment, a configuration different from that of the second embodiment will be described, and the same components as those of the second embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  The burner 31 of this embodiment is wound in a double manner so that the cooling water pipe 9 wound from the front end side of the oxidant supply pipe 7 is expanded in the circumferential direction in the first round. The inner winding pipe 33 and the outer winding pipe 35 constituting the cooling water pipe 9 are different from those of the second embodiment in that they are fixed to each other by a welding fixing portion 37.

  In the present embodiment, when there is a gap between the burner 31 and the through hole of the furnace wall, this embodiment is effective for preventing the adhesion and growth of slag starting from this gap. That is, if there is a gap in the outer peripheral portion of the burner 31, the flow stagnates in this gap, so that it is easy for slag to adhere and grow. In this regard, as in this embodiment, the gap between the burner 31 and the through hole can be reduced by winding the cooling water pipe 9 twice from the most distal portion of the burner 31. Thereby, adhesion and growth of the slag starting from the gap can be prevented, and the cooling efficiency on the tip side of the burner 31 can be increased, so that thermal damage to the tip portion of the burner 31 can be reliably prevented. Further, since the inner winding tube 33 is fixed to each other by the inclined surface 27 and the welding fixing portion 29, and the outer winding tube 35 is fixed to each other by the inner winding tube 33 and the welding fixing portion 37, the inner winding in the longitudinal direction of the burner 31 is obtained. The thermal elongation deformation of the tube 33 and the outer winding tube 35 can be restricted to some extent. Thereby, since the inner winding tube 33 and the outer winding tube 35 do not protrude into the high-temperature furnace, the tip portion of the burner 31 can be protected from a high heat load in the furnace, and the thermal damage is suppressed and stabilized. Operation can be realized.

  It is to be noted that the winding of the cooling water pipe 9 in a doubled manner is not limited to the first round as in the present embodiment, but the burner 31 is wound in a spiral manner over a plurality of rounds. In this case, it is necessary to fix the inner winding tube 33 and the outer winding tube 35 with the welding fixing portion 37.

(Fourth embodiment)
Next, a fourth embodiment of the burner to which the present invention is applied will be described with reference to FIG. In this embodiment, a configuration different from that of the third embodiment will be described, and the same components as those of the third embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  In the burner 41 of this embodiment, a cylindrical partition wall 43 is disposed between the outer peripheral surface of the combustion nozzle 5 and the inner peripheral surface of the oxidant supply pipe 7, and the inner peripheral surface of the partition wall 43 and the outer peripheral surface of the fuel nozzle 5. An annular flow path 45 through which the oxidant gas 11 flows is formed in the space between and the space between the outer peripheral surface of the partition wall 43 and the inner peripheral surface of the oxidant supply pipe 7 and does not contain oxygen. The third embodiment is different from the third embodiment in that an annular channel 49 through which 47 flows is formed. Here, the gas 47 is a gas that does not contain oxygen. For example, nitrogen, water vapor, or a part of the generated gas generated in the gasification furnace is used.

  In addition, the inclined surfaces 23 and 25 formed at the tip of the fuel nozzle 5 and the tip of the oxidant supply pipe 7 described in the second embodiment are respectively the tip of the fuel nozzle 5 in this embodiment. The oxidant gas 11 flows through the flow path 45 and is ejected in a cylindrical shape toward the axial center direction of the fuel nozzle 5. Yes.

  Thus, by having the structure which ejects the gas 47, the cooling effect of the front-end | tip part of the burner 41 accompanying the flow and ejection of the gas 47 can be acquired, and the temperature fluctuation of a front-end | tip part can be suppressed. In addition, due to the blowing effect caused by the ejection of the gas 47, adhesion and growth of the molten slag to the tip of the burner 41 can be suppressed.

  In addition, in this embodiment, since the flow path 49 through which the gas 47 flows is formed so as to surround the flow path 45 through which the oxidant gas 11 flows, the oxidant gas 11 ejected into the furnace A cylindrical curtain of gas 47 that does not contain oxygen is formed on the outside. By forming the curtain of the gas 47 in this way, contact between the combustible gas generated in the furnace and the oxidant gas can be suppressed, so that the recovery rate of the combustible gas can be improved. Moreover, since generation | occurrence | production of the high temperature field by the combustible gas and oxidizing agent gas reacting in the vicinity of the front-end | tip part of the burner 41 can be prevented, the thermal damage of the front-end | tip part of the burner 41 can be prevented.

  As mentioned above, although embodiment of this invention has been explained in full detail with drawing, the said embodiment is only an illustration of this invention and this invention is not limited only to the structure of the said embodiment. Needless to say, changes in design and the like within the scope of the present invention are included in the present invention.

  For example, in the above embodiment, the example in which the outer periphery of the fuel nozzle 5 is surrounded by the coaxial oxidant supply pipe 7 has been described. However, the outer periphery of the oxidant supply pipe 7 may be surrounded by the coaxial fuel nozzle 5. Good. In this case, an annular flow path through which the oxidant gas 11 flows is formed in the space between the outer peripheral surface of the oxidant supply pipe 7 and the inner peripheral surface of the fuel nozzle 5. A groove 13 is formed on the outer peripheral surface of the fuel nozzle 5.

  In this case, a cylindrical partition wall 43 may be disposed between the outer peripheral surface of the oxidant supply pipe 7 and the inner peripheral surface of the fuel nozzle 5. In this case, an annular channel through which the oxidant gas flows is formed in the space between the inner peripheral surface of the partition wall 43 and the outer peripheral surface of the oxidant supply pipe 7, and the outer peripheral surface of the partition wall 43 and the fuel nozzle 5. An annular flow path through which a gas not containing oxygen flows is formed in the space between the inner peripheral surface of the first and second inner surfaces.

DESCRIPTION OF SYMBOLS 1 Burner 3 Pulverized coal 5 Fuel nozzle 7 Oxidant supply pipe 9 Cooling water pipe 11 Oxidant gas 13 Groove 15 Cooling water supply pipe 17 Cooling water 21, 31, 41 Burner 23, 25, 27 Inclined surface 29, 37 Weld fixing part 33 Inner winding pipe 35 Outer winding pipe 43 Bulkhead 45, 49 Flow path 47 Gas

Claims (8)

A cylindrical fuel nozzle that ejects the pulverized fuel transported by the transport gas, and a cylindrical oxidant supply pipe provided coaxially with the fuel nozzle,
A burner in which a groove for mounting a cooling water pipe wound around the outer peripheral wall is formed in the other outer peripheral wall surrounding one of the fuel nozzle or the oxidant supply pipe.   The burner according to claim 1, wherein the groove is formed in a spiral shape along the outer peripheral wall.   The burner according to claim 1, wherein the groove is formed from a front end side of the outer peripheral wall where the winding of the cooling water pipe is started.   The burner according to any one of claims 1 to 3, wherein the groove has a groove depth equal to or larger than a radius of the cooling water pipe.   The annular flow path formed between one outer peripheral surface and the other inner peripheral surface of the front end portion of the fuel nozzle and the front end portion of the oxidant supply pipe has a gas ejected from the flow path, The burner in any one of Claims 1 thru | or 4 formed so that it may go to the axial center direction of one outer peripheral surface. A cylindrical fuel nozzle that ejects pulverized fuel conveyed by a carrier gas, a cylindrical oxidant supply pipe that is provided coaxially with the fuel nozzle, and one of the fuel nozzle or the oxidant supply pipe is enclosed. A cooling water pipe wound around the other outer peripheral wall,
In the outer peripheral wall, a groove in which the cooling water pipe is mounted is formed in a spiral shape,
The cooling water pipe wound from the front end side of the outer peripheral wall is a burner in which at least the first round is wound so as to overlap twice in the circumferential direction.   The space between the inner and outer winding pipes of the cooling water pipe wound twice on the outer peripheral wall and between the inner winding pipe and the outer peripheral wall are fixed by welding. Burner as described in. A cylindrical partition is provided between one outer peripheral surface and the other inner peripheral surface of the fuel nozzle and the oxidant supply pipe,
A space through which an oxidant gas flows is formed between the inner peripheral surface of the partition wall and the one outer peripheral surface, and a gas having no oxygen is formed between the outer peripheral surface of the partition wall and the other inner peripheral surface. The burner according to any one of claims 1 to 7, wherein a space through which the air flows is formed.

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