JP5818550B2 - Gasification burner - Google Patents

Description

  The present invention relates to a gasification burner, and more particularly to a structure of a gasification burner that supplies a pulverized coal raw material such as coal and a gasifying agent such as oxygen or air into a gasification furnace.

  As a method for gasifying coal, a fine solid fuel such as coal and a gasifying agent such as oxygen or air are supplied from a burner into a gasification furnace maintained at a high temperature, and combustible components in the fuel are burned. An air-bed coal gasification method is known in which combustible gases such as carbon monoxide and hydrogen are generated, and ash is converted to 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, hydrogen production systems used for coal liquefaction, chemical raw materials, and the like.

  A gasification furnace used in this type of gasification plant is provided with a gasification burner (hereinafter abbreviated as “burner”) for injecting fine solid fuel. This burner is generally inserted from the outside of the furnace through a through hole in the furnace wall, and is attached to the furnace wall with its tip protruding into the furnace. The tip of the burner inserted 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. When the tip of the burner is subjected to a large heat load in this way, melting of the tip, cracking, thinning due to high temperature corrosion, etc. occur, and the life of the burner is significantly reduced.

  Therefore, this kind of burner is provided with some cooling means. For example, a burner having a multi-tube structure in which the outer periphery of a 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 is disclosed. (For example, refer to Patent Document 1).

  By the way, the gasification furnace is filled with high temperature combustible gas produced | generated by reaction of a fine solid fuel and a gasifying agent. For this reason, the gasifying agent injected from the burner into the furnace mixes and reacts with the combustible gas, thereby causing a combustion reaction and generating a high temperature region. When such a high temperature region occurs in the vicinity of the burner tip, the burner tip may be subjected to a large heat load.

  As a structure for suppressing the generation of a high temperature region in the furnace, for example, a burner structure is disclosed in which a gasifying agent supply pipe is provided at the center and the outer peripheral side thereof is surrounded by a cylindrical fuel supply pipe. (For example, refer to Patent Document 2). According to this, since the pulverized solid fuel entrained in the carrier gas so as to surround the gasifying agent is ejected, combustion due to contact between the gasifying agent and the combustible gas in the furnace is suppressed, and the burner tip Generation of a high temperature region in the vicinity of the portion can be suppressed.

  In the burner of Patent Document 2, the gasifying agent jetted from the oxidant supply pipe goes straight through the jet of finely divided solid fuel supplied from the outer peripheral side, and the gasifying agent and the finely divided solid raw material Since the mixing is slow, the flame formation region by the burner is formed farther than the tip of the burner, and the influence of the heat load at the tip of the burner is reduced.

JP-A-10-288111

JP 2010-106132 A

  However, the burner disclosed in Patent Document 2 is, for example, a transfer device that is ejected from the tip of the burner due to the relationship between the area of the injection port of the finely divided solid fuel formed in an annular shape and the supply amount of the transfer gas that conveys the finely divided solid fuel. The gas and finely divided solid fuel may not be able to obtain an ejection speed sufficient to blow off slag adhering to the tip of the burner. For this reason, the slag adhering to the tip of the burner gradually grows, and as a result, the flame of the burner is deflected and the furnace wall is burned out, or the jet outlet of the pulverized solid fuel is closed and the gasifier is operated safely. May be disturbed.

  It is an object of the present invention to provide a gasification burner that reduces the influence of the thermal load received from the inside of the furnace, and suppresses the adhesion and growth of the slag at the tip of the burner and enables a stable operation of the gasification furnace. Let it be an issue.

  In order to solve the above problems, a gasification burner according to the present invention coaxially surrounds a first gasifying agent supply pipe through which a gasifying agent flows and an outer periphery of the first gasifying agent supply pipe. A fuel supply line through which finely divided solid fuel conveyed by a carrier gas flows and a second gasifying agent supply pipe through which a gasifying agent provided coaxially surrounding the outer periphery of the fuel supply line flows A gas flowing in the first gasifying agent supply line, and a cooling medium flow line through which the cooling medium provided surrounding the outer periphery of the second gasifying agent supply line flows The gasifying agent is ejected from the first ejection hole, and the gasifying agent flowing through the second gasifying agent supply conduit is ejected from a plurality of second ejection holes provided concentrically outside the fuel supply conduit. The ejection speed of the gasifying agent ejected from the second ejection hole is determined by the fine solid fuel ejected from the fuel supply line Characterized by comprising formed to be larger than the ejection speed.

  Thus, by dividing the gasifying agent outlet into the first outlet hole and the second outlet hole, the jetting speed of the gasifying agent jetted from the inner peripheral side and the outer peripheral side of the fine solid fuel outlet, respectively. And the amount of ejection can be adjusted. Here, by adjusting the gasifying agent ejected from the second ejection hole at a predetermined speed larger than the ejection speed of the finely divided solid fuel, the molten slag adhering to the burner tip is first adjusted. It becomes possible to blow away by the gasifying agent ejected from the two ejection holes. For this reason, adhesion and growth of the molten slag to the burner tip can be suppressed.

  In addition, the gasifying agent ejected from the first ejection hole goes straight through the jet of finely divided solid fuel accompanying the carrier gas to form a flame. Contact between the agent and the combustible gas in the furnace is suppressed, and a flame is formed at a position far from the burner tip. For this reason, the thermal load which a burner front-end | tip part receives from the inside of a furnace can be made small. Moreover, since the gasifying agent ejected from the second ejection hole only needs to be able to blow off the molten slag, the ejection amount (ejection amount per unit time) of the gasifying agent ejected from the second ejection hole is By adjusting the amount so that the molten slag can be blown away, the generation of a high temperature region in the vicinity of the burner tip can be suppressed.

  On the other hand, if the ejection amount of the gasifying agent ejected from the second ejection hole is increased more than necessary, the combustion reaction due to the contact between the combustible gas filling the furnace and the gasifying agent proceeds, and the burner tip portion is The heat load received from the inside of the furnace will increase.

  Here, the present inventors examined the relationship between the amount of gasification agent jetted from the outer peripheral side of the fine powder solid fuel jet outlet and the thermal load received from the furnace by the burner tip from the furnace. The results are shown in FIG. FIG. 5 shows the ratio (%) of the amount of gasification agent ejected from the outer peripheral side to the total amount of gasification agent ejected from the burner as a horizontal axis, and the ratio of heat flux (%) that the burner tip receives from the furnace. ) Is the vertical axis. In the figure, a numerical value on the horizontal axis of 0% corresponds to a gasification burner having a structure disclosed in Patent Document 2 when no gasifying agent is supplied from the outer peripheral side. On the contrary, when the numerical value on the horizontal axis is 100%, the entire amount of the gasifying agent is supplied from the outer peripheral side, which corresponds to the gasification burner having the structure disclosed in Patent Document 1.

  According to this result, even when 50% of the ejection amount of the total gasifying agent is ejected from the outer peripheral side of the pulverized solid fuel ejection port, that is, when half the amount is ejected, the increase in the thermal load applied to the burner tip is 10% or less. However, it has been found that the thermal load increases rapidly when more gasifying agent is supplied from the outer peripheral side.

  Therefore, the amount of gasification agent ejected from the second ejection hole is the sum of the gasification agent ejected from the first ejection hole and the gasification agent ejected from the second ejection hole. It shall be formed so that it may become less than half of the gasifying agent ejection amount. By doing in this way, the influence of the thermal load to a burner front-end | tip part can be decreased.

  Further, the second ejection hole may be formed so that the gasifying agent injected from the second ejection hole is injected in a direction parallel to the axial center of the first gasifying agent supply conduit. Good. By allowing the gasifying agent to be injected in such a direction, the effect of the gasifying agent blowing off the molten slag adhering to the burner tip surface can be enhanced most.

  The cooling medium flow conduit has an annular space through which the cooling medium flows and is defined by an outer peripheral side and an inner peripheral side with a partition wall therebetween. The tip of the cooling medium flow conduit has a hemispherical shape. The protrusion may be formed in an annular shape, and the inside of the tip portion may have a structure in which the cooling medium is folded back.

  Further, the cooling medium flow pipe is configured by spirally winding a cooling pipe through which the cooling medium flows along the outer peripheral surface of the second oxidant supply pipe. The winding may be started from the distal end side of the agent supply conduit.

  According to the gasification burner of the present invention, it is possible to reduce the influence of the thermal load received from the inside of the furnace. In addition, it is possible to suppress the adhesion and growth of the slag at the tip of the burner and realize a stable operation of the gasifier.

It is a front view of 1st Embodiment of the burner for gasification to which this invention is applied. It is a sectional side view of the gasification burner of FIG. It is a front view of 2nd Embodiment of the burner for gasification to which this invention is applied. It is a sectional side view of the gasification burner of FIG. It is a diagram which shows the relationship between the ejection amount of the gasifying agent ejected from the outer peripheral side of the fine powder solid fuel jet nozzle, and the thermal load which a burner front-end | tip part receives from the inside of a furnace.

(First embodiment)
Hereinafter, a first embodiment of a gasification burner to which the present invention is applied will be described with reference to FIGS. 1 and 2.

  The burner of this embodiment will be described as being provided on the furnace wall of a gasification furnace that gasifies pulverized coal, which is a pulverized solid fuel. However, the burner is not limited to this example as long as it burns fuel and a gasifying agent. It is not something that can be done. In the present embodiment, an oxidant gas such as oxygen or air is used as the gasifying agent, but is not limited thereto.

  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. The burner 1 includes a cylindrical gasifying agent supply pipe 3 located at the center, a cylindrical fuel supply pipe 5 provided coaxially surrounding the outer periphery of the gasifying agent supply pipe 3, and a fuel supply pipe 5. An annular cooling water supply pipe 7 provided so as to surround the outer periphery coaxially is provided.

  Inside the gasifying agent supply pipe 3 is a first gasifying agent supply pipe 9 through which the gasifying agent flows. An annular space formed between the outer peripheral surface of the gasifying agent supply pipe 3 and the inner peripheral surface of the fuel supply pipe 5 is a fuel supply pipe 11 through which the pulverized coal transported in the transport gas flows. . An annular space formed between the outer peripheral surface of the fuel supply pipe 5 and the inner peripheral surface of the cooling water supply pipe 7 serves as a second gasifying agent supply pipe 13 through which the gasifying agent flows. As the carrier gas flowing through the fuel supply line 11, an inert gas such as nitrogen that is inert to the combustion reaction is used.

  The gasifying agent flowing through the first gasifying agent supply line 9 is injected into the furnace from the injection hole 15, and the pulverized coal and the carrier gas flowing through the fuel supply line 11 are transferred from the annular injection port 17 into the furnace. It is supposed to be ejected. The gasifying agent flowing through the second gasifying agent supply pipe 13 is jetted into the furnace from a plurality of jet holes 19 provided concentrically outside the fuel supply pipe 11.

  The ejection hole 19 is formed through a diameter-enlarged portion 21 in which the outer peripheral surface of the distal end portion of the fuel supply pipe 5 is enlarged, and the gasifying agent injected from the ejection hole 19 is the axis of the gasifying agent supply pipe 3. It is formed obliquely so as to go in the direction. The ejection holes 19 are formed at equal intervals in the circumferential direction when viewed from the front (FIG. 1). The outer peripheral surface of the enlarged diameter portion 21 is in contact with the inner peripheral surface of the cooling water supply pipe 7.

  The cooling water supply pipe 7 has a double structure in which an internal cooling water pipe is partitioned into an inner channel 25 and an outer channel 27 by a partition wall 23. A tip end portion 29 of the cooling water supply pipe 7 protruding to the inside of the furnace is formed so as to project in a hemispherical shape inside the furnace, and the cooling water is folded back inside. Cooling water supplied from a cooling water supply port (not shown) flows through the inner flow path 25 and is turned back at the front end portion 29 in the furnace, and is discharged from a cooling water discharge port (not shown) after flowing through the outer flow path 27. It has become.

  The gasifying agent supplied to the first gasifying agent supply line 9 and the second gasifying agent supply line 13 is such that the gasifying agent supplied from a gasifying agent supply port (not shown) is branched in the middle. The first gasifying agent supply pipe 9 and the second gasifying agent supply pipe 13 are supplied. Further, the pulverized coal supplied to the fuel supply pipe 11 is supplied along with the transfer gas from a fuel supply port (not shown).

  In the burner 1 of the present embodiment, the pulverized coal ejected from the ejection port 17 is ejected at a speed of, for example, 10 to 20 m per second accompanying the carrier gas, whereas from the ejection hole 15 and the ejection hole 19 respectively. The gasifying agent to be ejected is formed so as to be ejected at a speed higher than the ejection speed of the pulverized coal ejected from the ejection port 17. For example, the gasifying agent ejected from the ejection hole 19 is ejected at a speed of 40 to 100 m per second, for example.

  On the other hand, the ejection amount of the gasifying agent ejected from the ejection hole 19 is half of the total gasifying agent ejection amount in which the gasifying agent ejected from the ejection hole 15 and the gasifying agent ejected from the ejection hole 19 are combined. That is, the opening area of the ejection hole 19, that is, the diameter of the ejection hole 19, the number of the ejection holes 19, and the like are set so as to be 50% or less. Here, the amount of ejection means the amount of ejection of the gasifying agent per unit time.

  In the burner 1 configured as described above, the gasifying agent is ejected into the furnace through the ejection holes 15 and 19, and the pulverized coal accompanying the carrier gas is ejected into the furnace through the ejection port 17. The pulverized coal sprayed into the furnace and the gasifying agent come into contact with each other to start a combustion reaction. This heat generation causes a gasification reaction to generate combustible gases such as carbon monoxide and hydrogen.

  The burner 1 of the present embodiment is provided with a plurality of ejection holes 19 on the outer side of the pulverized coal ejection port 17, and the gasifying agent ejected from the ejection holes 19 is ejected from the ejection port 17. Therefore, the molten slag adhering to the peripheral portion of the tip end surface of the burner 1 is easily blown away by the gasifying agent ejected from the ejection hole 19 at a high speed. Can do. For this reason, adhesion and growth of the molten slag to the tip surface of the burner 1 can be suppressed.

  Further, since the gasifying agent ejected from the ejection hole 15 goes straight through the jet of pulverized coal accompanying the carrier gas in the furnace, the flame of the burner 1 is far from the tip of the burner 1. On the other hand, in the vicinity of the tip portion of the burner 1, the gasifying agent ejected from the ejection hole 15 is surrounded by the pulverized coal transport gas, so that the gasifying agent and the combustible gas in the furnace Contact is suppressed. For this reason, the thermal load which the front-end | tip part of the burner 1 receives from the inside of a furnace can be decreased.

  Further, the gasifying agent ejected from the ejection hole 19 is an ejection amount that can blow off the molten slag adhering to the tip of the burner 1, that is, 50 of the total gasifying agent ejection amount ejected from the burner 1. % Is adjusted so that it is not mixed with the combustible gas in the furnace more than necessary. For this reason, generation | occurrence | production of the high temperature area | region in the vicinity of the front-end | tip part of the burner 1 can be suppressed.

(Second Embodiment)
Hereinafter, a second embodiment of a gasification burner to which the present invention is applied will be described with reference to FIGS. 3 and 4. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and configurations and features that are different from those in the first embodiment will be described.

  The burner 31 of the present embodiment is formed by connecting the outer peripheral surface of the enlarged diameter portion 21 formed at the distal end portion of the fuel supply pipe 5 so as to contact the inner peripheral surface of the cylindrical sealing pipe 33, An annular space formed by being sandwiched between the outer peripheral surface of the supply pipe 5 and the inner peripheral surface of the sealing pipe 33 is a second gasifying agent supply conduit 13 through which the gasifying agent flows. The enlarged diameter portion 21 is formed with an ejection hole 35 through which the gasifying agent is ejected. The ejection hole 35 is configured such that the gasifying agent injected from the ejection hole 35 is the axis of the gasifying agent supply pipe 3. It is formed so as to go in a direction parallel to the core.

  A cooling coil 37 is wound around the outer peripheral surface of the sealing tube 33. The cooling coil 37 is introduced into the furnace through the furnace wall from the outside of the furnace, and is communicated with one end of a cooling water introduction pipe 39 that extends toward the distal end side of the sealing pipe 33 and then bends. The sealing tube 33 is spirally wound from the distal end side to the proximal end side. As a result, the cooling water supplied from the outside of the furnace passes through the cooling water introduction pipe 39, and then the cooling coil 37 wound around the sealing pipe 33 is substantially aligned with the axial center of the gasifying agent supply pipe 3. It flows in the tangential direction and is returned to the outside of the furnace.

  The burner 31 of this embodiment is suitable when gasifying a coal type having relatively high combustibility or gasification reactivity such as subbituminous coal or lignite. When gasifying such a coal type, as in the first embodiment, the gasifying agent ejected from the ejection hole 19 is ejected toward the axial center of the gasifying agent supply pipe 3, and It is not necessary to promote mixing, and the gasifying agent ejected from the ejection holes 19 is ejected in parallel to the direction of the pulverized coal jet, thereby further enhancing the penetration force of the jet and adhering to the tip of the burner 1 The effect of blowing off can be enhanced. Thereby, adhesion and growth of the molten slag to the tip surface of the burner 1 can be effectively suppressed.

  Also in the burner 31 of the present embodiment, the gasifying agent ejected from the ejection hole 15 goes straight so as to pass through the jet of pulverized coal accompanying the carrier gas, so that the flame formation region is the burner 1. On the other hand, in the vicinity of the tip of the burner 1, the gasifying agent ejected from the ejection hole 15 is surrounded by the pulverized coal transfer gas, so that the gasifying agent and combustion in the furnace are performed. Contact with the sex gas is suppressed. For this reason, the thermal load which the front-end | tip part of the burner 1 receives from the inside of a furnace can be decreased.

  Further, the gasifying agent ejected from the ejection hole 35 is an ejection amount that can blow off the molten slag adhering to the tip of the burner 1, that is, 50 of the total gasifying agent ejection amount ejected from the burner 1. By adjusting to% or less, generation of a high temperature region in the vicinity of the tip of the burner 1 can be suppressed.

  As described above, according to the above-described embodiment, the burner tip can be protected from an excessive heat load from the inside of the furnace, so cracks and high temperature oxidation / sulfurization corrosion caused by thermal fatigue of the burner tip It is possible to suppress the occurrence of thinning due to, and to improve the life of the burner. Further, since adhesion and growth of the molten slag to the tip of the burner can be suppressed, there is no occurrence of deflection of the flame of the burner due to the adhesion or growth of the slag or clogging of the pulverized coal jet 17 and the like. Operation of the gasifier can be realized.

  In 1st Embodiment and 2nd Embodiment, in addition to the cooling structure, the example from which the structure of the 2nd gasifying agent supply pipe line 13 and the ejection holes 19 and 35 differs was demonstrated, However, It is limited to these structures For example, only the cooling structure of both embodiments may be replaced, or only the structure of the ejection holes 19 and 35 may be replaced. In short, the fuel supply line 11 is arranged on the outer peripheral side of the first gasifying agent supply line 9, the second gasifying agent supply line 13 is arranged on the outer peripheral side of the fuel supply line 11, and the first 2 is arranged on the outer peripheral side of the gasifying agent supply pipe 13, and the ejection speed of the gasifying agent ejected from the ejection holes 19 and 35 is larger than the ejection speed of the pulverized coal ejected from the ejection port 17. What is necessary is just to be formed so that it may become.

  Japanese Patent Laid-Open No. 9-243028 discloses a multiple structure burner in which a fuel gas channel is formed on the outer peripheral side of the primary oxygen channel and a secondary oxygen channel is further formed on the outer peripheral side thereof. However, this is to form a low-intensity flame having a long stable flame length by making the ejection speed of the secondary oxygen lower than the ejection speed of the fuel gas. On the other hand, the burner 1 to which the present invention is applied has no problem in the flame holding property of the pulverized coal, but rather the outer periphery of the pulverized coal ejection port 17 in order to blow off the molten slag adhering to or growing on the tip of the burner. From the side, it is essential that the gasifying agent be ejected at a speed faster than the ejection speed of the pulverized coal. For this reason, in the technique of the above publication, the molten slag adhering to the burner tip cannot be blown off.

1,31 Burner 3 Gasifying agent supply pipe 5 Fuel supply pipe 7 Cooling water supply pipe 9 First gasifying agent supply line 11 Fuel supply line 13 Second gasifying agent supply line 15, 19, 35 Hole 17 Spout 21 Expanded portion 23 Partition wall 25 Inner flow path 27 Outer flow path 29 Tip portion 33 Sealing pipe 37 Cooling coil 39 Cooling water introduction pipe

Claims (5)

A cylindrical first gasifying agent supply pipe through which the gasifying agent flows, and a finely divided solid fuel which is provided so as to coaxially surround the outer periphery of the first gasifying agent supply pipe and which is carried by the carrier gas Between the first gasifying agent supply line and a cylindrical fuel supply line, and an outer periphery of the fuel supply line coaxially surrounding the fuel supply line. A cylindrical second gasifying agent supply line through which the agent flows, and a cooling medium flow line through which the cooling medium provided surrounding the outer periphery of the second gasifying agent supply line flows With
The gasifying agent flowing through the first gasifying agent supply conduit is ejected from a first ejection hole formed by opening the entire tip of the conduit, and flows through the second gasifying agent supply conduit. The agent is ejected from a plurality of second ejection holes provided concentrically outside the fuel supply pipeline,
A gasification burner formed such that an ejection speed of the gasifying agent ejected from the second ejection hole is larger than an ejection speed of the finely divided solid fuel ejected from the fuel supply pipe.   The ejection amount of the gasifying agent ejected from the second ejection hole is the sum of the gasifying agent ejected from the first ejection hole and the gasifying agent ejected from the second ejection hole. The gasification burner according to claim 1, wherein the burner is formed so as to be less than or equal to half of the total gasifying agent ejection amount.   The second ejection hole is formed such that the gasifying agent ejected from the second ejection hole is ejected in a direction parallel to the axial center of the first gasifying agent supply conduit. The gasification burner according to claim 1 or 2.   In the cooling medium flow conduit, an annular space through which the cooling medium flows is defined by an outer peripheral side and an inner peripheral side with a partition wall therebetween, and a tip portion of the cooling medium flow conduit has a hemispherical shape. The gasification burner according to any one of claims 1 to 3, wherein the gasification burner is formed so as to project in an annular shape, and an inner side of a tip portion of the cooling medium is folded back. The cooling medium flow pipe is configured by spirally winding a cooling pipe through which the cooling medium flows along the outer peripheral surface of the second oxidant supply pipe. The gasification burner according to any one of claims 1 to 3, wherein winding is started from the front end side of the oxidant supply pipe.

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