JP2014126354A - Burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burner which suppresses thermal damage of a top end part of the burner formed by winding a cooling water pipe around an outer circumferential surface of an oxidant supply pipe.SOLUTION: A burner 1 includes a cylindrical fuel nozzle 5 which jets powder fuel carried by carrying gas, a cylindrical oxidant supply pipe 7 which coaxially surrounds the outer circumferential surface of the fuel nozzle 5 and cooling water pipes 9 wound around the outer circumferential surface of the oxidant supply pipe 7. Therein, spiral grooves 17 to which the cooling water pipes 9 are closely attached are formed on the outer circumferential surface of the oxidant supply pipe 7, the cooling water pipes 9 are formed in piles such that at least first one cycle wound around the top end part of the outer circumferential surface of the oxidant supply pipe 7 expands the diameter, a cooling water inlet pipe 21 communicated with the first one cycle of the cooling water pipe 9 is disposed apart from the outer circumferential surface of the oxidant supply pipe 7 and a part of the other cooling water pipes 9 besides the first one cycle of the cooling water pipe is welded and fastened to at least one of the cooling water inlet pipe 21 and the 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 for generation thermal power generation systems and hydrogen production systems used for coal liquefaction and chemical raw materials.

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

  By the way, the tip of the burner protruding into the furnace is not only exposed to a high temperature higher than the melting temperature of ash, but may be subjected to a large heat load due to adhesion or peeling 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. Therefore, this type of burner surrounds the outer peripheral surface of the fuel nozzle with a coaxial cylindrical oxidant supply pipe, and further surrounds the outer peripheral surface of the oxidant supply pipe with a cooling water pipe through which cooling water flows. Is widely adopted.

  Patent Document 1 discloses a burner structure 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. Thus, 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 affected by the heat in the furnace and is deformed to some extent in the longitudinal direction, but 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, The thermal expansion deformation is absorbed by the seal expansion structure provided outside the furnace.

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, there is a risk of thermal expansion deformation when the cooling water pipe receives a large heat load in the furnace. . That is, the cooling water pipe is spirally formed from the outer peripheral surface on the front end side of the oxidant supply pipe after bending the front end side of the cooling water inlet pipe extending from the outside of the furnace through the through hole of the furnace wall and extending to the front end side of the burner. It is formed by wrapping around. For this reason, although the cooling water inlet pipe is restrained to some extent, the spiral cooling water pipe is almost restrained in the longitudinal direction of the burner. Therefore, when the tip of the burner is subjected to a large heat load, the cooling water pipe undergoes thermal elongation deformation in the longitudinal direction of the burner and protrudes inside the high-temperature furnace, and the tip of the burner is insufficiently cooled and thermally damaged. There is a fear.

  In addition, as a result of the cooling water pipe being deformed by thermal expansion in this way, when the jet flow from the burner is deflected, the molten slag is likely to adhere to the tip of the burner, and the adhered molten slag grows, thereby causing a gasification furnace. There is a risk of disturbing the stable operation of the plant.

  On the other hand, it is conceivable to suppress thermal expansion deformation of the cooling water pipe by fixing the cooling water pipe to the outer peripheral surface of the oxidant supply pipe. However, since the temperature of the fixed part by welding is likely to be higher than the surface of the cooling water pipe, when the tip of the burner is subjected to a large heat load, not only excessive thermal stress is generated in the fixed part, but also the high temperature There is a risk of thinning due to oxidation or sulfidation corrosion, causing thermal damage to the cooling water pipe.

  This invention makes it a subject to suppress the thermal damage of the front-end | tip part of the burner formed by winding a cooling water pipe around the outer peripheral surface of an oxidizing agent supply pipe.

  In order to solve the above problems, a burner according to the present invention includes a cylindrical fuel nozzle that ejects a pulverized fuel conveyed by a carrier gas, and a cylindrical oxidant supply pipe that coaxially surrounds the outer peripheral surface of the fuel nozzle. And a cooling water pipe wound around the outer peripheral surface of the oxidant supply pipe, and in a burner in which a spiral groove to which the cooling water pipe is closely attached is formed on the outer peripheral surface of the oxidant supply pipe, The water pipe is formed so that at least the first round wound around the tip of the outer peripheral surface of the oxidant supply pipe is expanded, and a cooling water inlet pipe communicating with the first round cooling water pipe is provided. A part of the other cooling water pipe except the first one round cooling water pipe is welded and fixed to at least one of the cooling water inlet pipe and the oxidant supply pipe. It is characterized by.

  Thus, the cooling efficiency of the front-end | tip part of a burner can be improved by forming so that the diameter of at least the 1st round of the cooling water pipe wound around an oxidizing agent supply pipe may be expanded. Here, the fixed part by welding of the cooling water pipe is strongly influenced by the heat load in the furnace toward the tip of the burner, and is easily damaged by heat. Therefore, without welding the first cooling water pipe, By fixing the cooling water pipe of the portion by welding, it is possible to prevent thermal damage of the cooling water pipe with the welded portion as a base point, and to increase the binding force of the cooling water pipe of the first round and suppress the thermal elongation deformation. In addition, since the first one-round cooling water pipe is not provided with a fixing portion by welding, the first one-round cooling water pipe can uniformly cool the oxidant supply pipe over the entire circumference, and the tip of the burner The cooling efficiency can be increased. Therefore, according to the present invention, since thermal deterioration and thermal elongation deformation of the cooling water pipe can be suppressed, thermal damage due to insufficient cooling of the tip of the burner can be prevented, and the gasification furnace can be operated stably.

  In this case, a cylindrical partition that coaxially surrounds the outer peripheral surface of the fuel nozzle is provided between the outer peripheral surface of the fuel nozzle and the inner peripheral surface of the oxidant supply pipe. A space through which oxidant gas flows is formed between the outer peripheral surface, and a space through which gas without oxygen flows is formed between the outer peripheral surface of the partition wall and the inner peripheral surface of the oxidant supply pipe. Shall.

  According to this, since it is possible to obtain a cooling effect on the tip of the burner accompanying the flow and ejection of a gas that does not contain oxygen, it is possible to suppress temperature fluctuations at the tip of the burner due to fluctuations in the thermal load in the furnace. It is possible to more reliably prevent thermal deterioration of the tip of the burner.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal damage of the front-end | tip part of the burner formed by winding a cooling water pipe around the outer peripheral surface of an oxidizing agent supply pipe can be suppressed, and the stable operation | movement of a gasifier can be implement | achieved.

It is a figure which shows the structure of 1st Embodiment of the burner to which this invention is applied, (a) is a front view, (b) is sectional drawing. It is a figure which shows the structure of 2nd Embodiment of the burner to which this invention is applied, (a) is a front view, (b) is sectional drawing.

(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 this embodiment is inserted into a through-hole in a furnace wall of a gasification furnace (not shown), and is attached to the furnace wall in a state where the tip side protrudes from the furnace wall to the inside of the furnace. The burner 1 includes a cylindrical fuel nozzle 5 in which a space for transporting pulverized coal 3 accompanied by a transport gas such as nitrogen gas is formed, and a cylinder provided so as to coaxially surround the outer periphery of the fuel nozzle 5. And a small-diameter cooling water pipe 9 wound around the outer peripheral surface of the oxidant supply pipe 7. 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.

  The pulverized coal 3 flowing along with the carrier gas through the space inside the fuel nozzle 5 is ejected into the furnace from the ejection port 12, and between the outer peripheral surface of the fuel nozzle 5 and the inner peripheral surface of the oxidant supply pipe 7. The oxidant gas 11 flowing through the annular space is ejected into the furnace from a plurality of (eight in this embodiment) ejection holes 14 provided concentrically outside the tip of the fuel nozzle 5. It is like that.

  An annular space formed in the 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 forms a predetermined angle toward the axial direction of the fuel nozzle 5. It is formed. That is, the outer peripheral surface of the tip portion of the fuel nozzle 5 is formed as a conical inclined surface 13 whose diameter is reduced toward the tip side, and the tip portion of the oxidant supply pipe 7 facing the inclined surface 13 is formed. The inner peripheral surface is formed as a tapered inclined surface 15 spaced apart from the inclined surface 13 by a certain distance. By comprising in this way, since the contact efficiency of the pulverized coal 3 ejected in the furnace from the jet nozzle 12 and the oxidant gas 11 ejected in the furnace from the ejection hole 14 is improved, pulverized coal 3 and oxidation The agent gas 11 can react efficiently to increase the gasification efficiency.

  On the outer peripheral surface of the oxidant supply pipe 7, a groove 17 in which the cooling water pipe 9 is mounted is formed in a spiral shape. The groove 17 has a semicircular cross section, and the cooling water pipe 9 having a circular cross section is attached in close contact with the groove 17.

  On the other hand, since the inner peripheral surface of the tip of the oxidant supply pipe 7 forms an inclined surface 15, the outer peripheral surface on the back side thereof forms a conical inclined surface 19 whose diameter decreases toward the tip side. Here, when the groove 17 is to be formed at the tip portion of the burner, it is extremely difficult to form the semicircular groove 17 at the tip portion having a complicated shape as in the present embodiment. . Therefore, as shown in FIG. 1, the groove 17 a formed at the foremost end has a cross-sectional shape in which about half of the front end side is continuous with the inclined surface 19 and opened to the front end side.

  The cooling water pipe 9 is bent at the front end side of the cooling water inlet pipe 21 that penetrates the furnace wall from the outside of the furnace and extends to the front end side of the oxidant supply pipe 7 in the furnace, and the front end of the outer peripheral surface of the oxidant supply pipe 7. It is formed by spirally winding from the side to the outer peripheral surface. The cooling water pipe 9 is wound twice so that the first round wound around the oxidant supply pipe 7 is expanded in the circumferential direction. The inner winding tube 23 and the outer winding tube 25 wound twice are provided so as to overlap each other in the circumferential direction, and the inner winding tube 23 is in close contact with the groove 17a. In this embodiment, the cooling water 27 supplied from the outside of the furnace via the cooling water inlet pipe 21 flows through the first round of the cooling water pipe 9 in the order of the outer winding pipe 25 and the inner winding pipe 23, and then 2 It flows spirally through the cooling water pipe 9 after the circumference and returns to the outside of the furnace.

  In the present embodiment, the first round of the cooling water pipe 9 is wound twice. However, the cooling water pipe 9 is not limited to double, and can be wound, for example, three or more times. In addition to the first round, the cooling water pipe 9 can also be wound in the same manner after the second round.

  Since the cooling water pipe 9 is attached in close contact with the groove 17, the cooling water pipe 9 is restricted to some extent in the longitudinal direction of the burner 1. Therefore, even when the thermal load that the tip of the burner 1 receives from the inside of the furnace becomes large due to fluctuations in the furnace temperature, adhesion of molten slag, repeated peeling, etc., the cooling water pipe 9 is applied to the oxidant supply pipe 7. It is suppressed that the oxidant supply pipe 7 is thermally stretched and deformed in the longitudinal direction and protrudes into a high-temperature furnace. Therefore, the front-end | tip part of the burner 1 can be protected from the heat load in a furnace. Further, since the deflection of the jet flow from the burner 1 can be suppressed by suppressing the thermal expansion deformation of the cooling water pipe 9 in this way, it is possible to prevent the molten slag from adhering to the tip of the burner 1 and growing. Can do. Further, since the groove 17 is formed according to 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 17. Therefore, the cooling efficiency of the burner 1 can be increased.

  Further, in the present embodiment, the cooling water pipe 9 can be increased in the cooling efficiency of the tip end portion of the burner 1 because the first round is overlapped in the diameter increasing direction and is wound twice. In particular, if there is a gap between the burner 1 and the through-hole in the furnace wall, slag is likely to adhere and grow with this gap as the starting point. By turning, the gap between the burner 1 and the through-hole can be reduced, so that it is possible to prevent the slag from adhering to and growing from the gap.

  By the way, since the cooling water pipe 9 is attached in close contact with the groove, the cooling water pipe 9 is restrained to some extent in the longitudinal direction of the burner 1, but between the inner winding pipe 23 and the outer winding pipe 25 and between the inner winding pipe 23. And the groove 17a are not restrained at all (the inner tube 23 is only in close contact with the groove 17a opened toward the distal end side, and is not restrained in the longitudinal direction of the burner 1). Therefore, when the first round of the cooling water pipe 9 is deformed by thermal expansion, the cooling effect of the tip portion of the burner 1 is lost, and there is a risk of causing thermal damage to the tip portion of the burner 1.

  In this respect, the cooling water pipe 9 of the present embodiment has a cooling water inlet pipe 21 in which the second cooling water pipe 9 wound around the oxidant supply pipe 7 is arranged away from the outer peripheral surface of the oxidant supply pipe 7. Are fixed by welding with a welding fixing portion 29. Here, it is important that the cooling water pipe 9 is not provided with a weld fixing portion in the cooling water pipe 9 of the first round. That is, the temperature of the weld fixing portion 29 of the cooling water pipe 9 is more likely to rise than the surface of the cooling water pipe 9, and the temperature tends to rise due to the influence of the heat load in the furnace toward the tip of the burner 1. The cooling water pipe 9 is welded and fixed for the second and subsequent rounds without welding. Thereby, the cooling water pipe 9 of the first round can be restrained with a certain restraining force while preventing the heat damage of the cooling water pipe 9 with the weld fixing portion 29 as a base point. As a result, the first round of the cooling water pipe 9 is not excessively thermally deformed to cause poor cooling at the tip of the burner 1 or the jet of the burner 1 is not obstructed by the cooling water pipe 9 that has been deformed by heat. Moreover, since the cooling water pipe 9 of the first round does not have a welding fixing part, the oxidant supply pipe 7 can be cooled uniformly and efficiently in the circumferential direction. Therefore, according to the present embodiment, the cooling efficiency of the tip end portion of the burner 1 by the cooling water pipe 9 can be increased, and the thermal deterioration and thermal elongation deformation of the cooling water pipe 9 can be suppressed. Thermal damage due to insufficient cooling can be prevented, and stable operation can be realized.

  In this embodiment, the welding fixing portion 29 is provided immediately before the tip of the burner 1, that is, on the second turn of the cooling water pipe 9, but the position where the welding fixing portion 29 is provided except for the first round, For example, the cooling water pipe 9 and the cooling water inlet pipe 21 in the third and subsequent rounds may be fixed by welding. Further, the mating member to be welded and fixed to the cooling water pipe 9 is not limited to the cooling water inlet pipe 21. For example, the cooling water pipe 9 may be welded to the outer peripheral surface of the oxidant supply pipe 7. Furthermore, the welding fixing part 29 of the cooling water pipe 9 is not limited to one place, and may be provided at a plurality of places.

(Second Embodiment)
Next, a second 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 first embodiment will be described, and the same components as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  In the burner 31 of this embodiment, a cylindrical partition wall 37 that coaxially surrounds the outer peripheral surface of the fuel nozzle 33 is disposed between the outer peripheral surface of the fuel nozzle 33 and the inner peripheral surface of the oxidant supply pipe 35. An annular space through which the oxidant gas 11 flows is formed between the outer peripheral surface of 33 and the inner peripheral surface of the partition wall 37, and between the outer peripheral surface of the partition wall 37 and the inner peripheral surface of the oxidant supply pipe 35. This is different from the first embodiment in that an annular space through which a gas 39 not containing oxygen flows is formed. Here, the gas 39 means a gas that does not contain oxygen, and for example, an inert gas such as nitrogen or carbon dioxide gas, water vapor, or a part of a generated gas generated in a gasification furnace can be used.

  The pulverized coal 3 flowing through the space inside the fuel nozzle 33 together with the carrier gas is jetted into the furnace from the jet port 40 and passes through the space between the outer peripheral surface of the fuel nozzle 33 and the inner peripheral surface of the partition wall 37. The flowing oxidant gas 11 is ejected into the furnace through a plurality of (eight in this embodiment) ejection holes 42 provided concentrically outside the fuel nozzle 33, and the outer peripheral surface of the partition wall 37 and the oxidant supply pipe. The gas 39 flowing through the space between the inner peripheral surface 35 is ejected from the annular ejection port 44 into the furnace.

  In addition, in the present embodiment, the inclined surfaces 13 and 15 formed at the tip of the fuel nozzle 5 and the tip of the oxidant supply pipe 7 described in the first embodiment are respectively the tip of the fuel nozzle 33. The oxidant gas 11 flows through the flow path between the inclined surface 41 and the inclined surface 43 and flows from the ejection hole 42 to the axial center of the fuel nozzle 33. It is designed to erupt in the direction.

  According to the present embodiment, the same operation and effect as the first embodiment can be obtained. Moreover, by having the structure which ejects the gas 39 in this way, the cooling effect of the front-end | tip part of the burner 31 accompanying the flow and ejection of the gas 39 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 39, adhesion and growth of the molten slag to the tip portion of the burner 31 can be suppressed.

  In addition, in this embodiment, since the flow path through which the gas 39 flows is formed so as to surround the flow path through which the oxidant gas 11 flows, outside the oxidant gas 11 injected into the furnace. Forms a cylindrical curtain of gas 39 which does not contain oxygen. By forming the curtain of the gas 39 in this way, contact between the combustible gas generated in the furnace and the oxidant gas 11 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 the oxidizing gas 11 reacting in the vicinity of the front-end | tip part of the burner 31 can be prevented, the thermal damage of the front-end | tip part of the burner 31 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, an example in which the flow path through which the oxidant gas 11 flows is formed at the tip of the burners 1 and 31 has been described, but the fuel nozzles 5 and 33 are not provided with such an inclined structure. On the other hand, you may form the oxidizing agent supply pipe | tube 7 and the partition 37 as a straight structure.

DESCRIPTION OF SYMBOLS 1,31 Burner 3 Pulverized coal 5,33 Fuel nozzle 7,35 Oxidant supply pipe 9 Cooling water pipe 11 Oxidant gas 17 Groove 21 Cooling water inlet pipe 23 Inner winding pipe 25 Outer winding pipe 27 Cooling water 29 Welding fixing part 37 Partition 39 Gas

Claims (2)

A cylindrical fuel nozzle that ejects pulverized fuel conveyed by the carrier gas, a cylindrical oxidant supply pipe that coaxially surrounds the outer peripheral surface of the fuel nozzle, and a wrap around the outer peripheral surface of the oxidant supply pipe A burner in which a spiral groove to which the cooling water pipe is closely attached is formed on the outer peripheral surface of the oxidant supply pipe.
The cooling water pipe is formed so that at least the first round wound around the tip of the outer peripheral surface of the oxidant supply pipe is expanded, and the cooling water communicated with the cooling water pipe of the first round. An inlet pipe is provided apart from the outer peripheral surface of the oxidant supply pipe;
A part of the cooling water pipe other than the first round cooling water pipe is welded and fixed to at least one of the cooling water inlet pipe or the oxidant supply pipe. Between the outer peripheral surface of the fuel nozzle and the inner peripheral surface of the oxidant supply pipe, a cylindrical partition wall that coaxially surrounds the outer peripheral surface of the fuel nozzle is provided,
A space through which oxidant gas flows is formed between the inner peripheral surface of the partition wall and the outer peripheral surface of the fuel nozzle, and oxygen is provided between the outer peripheral surface of the partition wall and the inner peripheral surface of the oxidant supply pipe. The burner according to claim 1, wherein a space through which a gas that does not exist flows is formed.

Images