JP6171543B2 - Burner - Google Patents

Description

  The present invention relates to a burner that burns fuel with a low volatile content.

  In recent years, fuels used in boilers have been provided with low volatile fuels, such as anthracite, semi-anthracite or oil coke, and burners are also required to have the ability to burn low volatile fuels.

  Among these, in particular, when anthracite with a small amount of volatiles is used as fuel, it is difficult to exclusively burn anthracite. And mixed with primary air that also serves as a carrier medium and combustion air.

  However, when anthracite and sub-bituminous coal are mixed and used, oxygen is consumed by burning first sub-bituminous coal with good combustibility, and the oxygen concentration of the primary air decreases. For this reason, oxygen for burning the anthracite coal is not sufficiently supplied, and the combustibility of the anthracite coal may be deteriorated, and the effect of improving the combustibility by using the anthracite coal and the subbituminous coal may not be obtained. There was this.

  In Patent Document 1, a chamber is provided in the burner, and a mixed flow of pulverized coal and primary combustion air is ejected into the chamber, and an internal circulation flow that induces hot gas in the furnace into the chamber is generated. A low-volatile fuel burner device is disclosed in which pulverized coal is heated early by an internal circulation flow so that volatile components are released, and self-sustainable combustion is possible even with low-volatile pulverized coal.

JP 2008-138901 A

  In view of such circumstances, the present invention provides a burner that can increase the oxygen concentration in a pulverized coal stream and burn low-volatile fuel.

  The present invention relates to a concave hole formed in a furnace wall surface, a bottomed cylindrical burner chamber disposed concentrically with the concave hole and provided with an air supply hole for auxiliary combustion provided at the core side end, and the burner A pulverized coal mixed flow jet pipe opening at a position eccentric to the bottom of the chamber and ejecting a pulverized coal mixed flow, and an eccentric side opposite to the axis of the pulverized coal mixed flow jet pipe and the burner chamber at the bottom of the burner chamber A tertiary air ejection pipe that opens to the position and ejects temperature-adjusting air; and a secondary air ejection section in a ring-shaped space that is formed between the burner chamber and the concave hole to eject combustion air. Further, the present invention relates to a burner that can supply a part of the combustion air into the burner chamber from the auxiliary combustion air supply hole.

  Further, the present invention is such that the pulverized coal mixed flow is ejected from the pulverized coal mixed flow ejection pipe, so that a positive pressure region is formed in the burner chamber along the pulverized coal mixed flow. A burner configured so that a negative pressure region is formed on the opposite side, the auxiliary combustion air supply hole is provided on the positive pressure region side, and the auxiliary combustion air is supplied to the positive pressure region It is.

  The present invention also relates to a burner in which a small number of auxiliary combustion air supply holes are provided in the burner chamber.

  Further, the present invention relates to a burner in which the auxiliary combustion air supply hole is provided in the bottom portion, and the auxiliary combustion air is supplied into the burner chamber in the axial direction.

  The present invention further relates to a burner further comprising a flow rate adjusting plate slidably provided on the outer surface of the base end of the bottom portion, wherein the auxiliary combustion air supply hole can be opened and closed by sliding the flow rate adjusting plate. Is.

  According to the present invention, there is provided a burner configured such that the auxiliary combustion air supply hole is provided horizontally through the peripheral surface of the burner chamber so that the auxiliary combustion air is supplied horizontally into the burner chamber. It is related.

  The present invention further relates to a burner further comprising a guide channel for deflecting the combustion air in the horizontal direction, the guide channel communicating with the auxiliary combustion air supply hole.

  The present invention further includes an auxiliary combustion air guide block in which the guide flow path is formed, and an open / close shutter slidably provided on the auxiliary combustion air guide block. The present invention relates to a burner that can open and close the guide channel.

  Furthermore, the present invention further includes a cylindrical opening / closing member provided so that the peripheral surface of the burner chamber is slidable in the axial direction, and the auxiliary combustion air supply hole is opened / closed by sliding of the opening / closing member. It relates to the burner that was made possible.

  According to the present invention, a concave hole formed in the furnace wall surface, a bottomed cylindrical burner chamber disposed concentrically with the concave hole and provided with a core-side tip and an auxiliary combustion air supply hole; A pulverized coal mixed flow jet pipe which opens at a position eccentric to the bottom of the burner chamber and ejects a pulverized coal mixed flow, and the pulverized coal mixed flow jet pipe at the bottom of the burner chamber is opposite to the axial center of the burner chamber. A tertiary air ejection pipe that opens at a position eccentric to the center and ejects temperature adjusting air, and a secondary air ejection portion in a ring-shaped space that is formed between the burner chamber and the concave hole and that ejects combustion air; And a part of the combustion air can be supplied into the burner chamber from the auxiliary combustion air supply hole, so that when pulverized coal having different combustibility is mixed and burned, it is burned with a delay. Against low volatile pulverized coal Can be supplied with sufficient oxygen, there is exhibited an excellent effect that it is possible to improve the combustibility of the low volatile content of the pulverized coal.

It is a schematic sectional drawing of the burner which concerns on 1st Example of this invention. (A) is an AA arrow view of FIG. 1, (B) is a BB arrow view of FIG. It is a schematic sectional drawing of the burner which concerns on the 2nd Example of this invention. It is CC arrow line view of FIG. It is a schematic sectional drawing of the burner which concerns on the 3rd Example of this invention. FIG. 6 is a DD arrow view of FIG. 5. It is a schematic sectional drawing of the burner which concerns on the 4th Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the burner 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1, 2A and 2B.

  In FIG. 1, reference numeral 2 denotes a furnace wall of a pulverized coal-fired boiler, which is made of a heat-resistant material such as a refractory brick or a water-cooled wall pipe. The burner 1 which is a required number of low volatile fuel burners is provided at a required portion of the furnace wall 2.

  The furnace wall 2 is provided with a concave hole 3 penetrating the furnace wall 2, and a furnace inner peripheral edge portion of the concave hole 3 is formed with a tapered portion 4 whose diameter increases toward the core.

  A burner cover 5 is provided on the outer peripheral side of the furnace wall 2 at a required distance from the outer peripheral surface of the furnace wall 2, and a burner chamber 6 provided concentrically with the concave hole 3 is provided in the burner cover 5. It is supported.

  The burner chamber 6 has a substantially cylindrical shape having a horizontal axis, and is fixed to the burner cover 5 on the base end side (side away from the core), and a part of the base end portion is more than the burner cover 5. It protrudes to the base end side. A tip end portion of the burner chamber 6 is a tapered skirt portion 7 whose diameter increases toward the core, and a base end portion is closed by a bottom portion 8.

  A pulverized coal mixed flow jet pipe 9 that is parallel to the axis of the burner chamber 6 is opened to the bottom portion 8. From the pulverized coal mixed flow jet pipe 9, for example, anthracite and flammable low-volatile fuel with low flammability are provided. A pulverized coal mixed stream 11 of mixed pulverized coal mixed with good subbituminous coal and primary air heated to a required temperature and serving as a carrier medium and combustion air is ejected. Further, a tertiary air ejection pipe 12 parallel to the axis of the burner chamber 6 is opened at the bottom 8, and temperature adjusting air 13 as tertiary air is ejected from the tertiary air ejection pipe 12. .

  The opening position of the pulverized coal mixed flow jet pipe 9 and the opening position of the tertiary air jet pipe 12 are eccentric with respect to the axis of the burner chamber 6, and the opening of the pulverized coal mixed flow jet pipe 9 is open. The position (lower side with respect to the paper surface in FIG. 1) and the opening position of the tertiary air ejection pipe 12 (upper side with respect to the paper surface in FIG. 1) are eccentric to the opposite side with respect to the axis of the burner chamber 6. .

  Between the skirt portion 7 and the tapered portion 4, a tapered ring-shaped secondary air ejection portion 14 is formed. Further, a secondary air conduction path 17 is constituted by a space 15 formed between the furnace wall 2 and the burner cover 5 and a space 16 formed between the burner chamber 6 and the recessed hole 3, The secondary air conduction path 17 communicates with the secondary air ejection part 14, and combustion air 10 as secondary air is ejected from the secondary air ejection part 14.

  In the space 15, variable swirl vanes 18 are disposed around the concave hole 3 at a required interval, and the variable swirl vane 18 has a rotation axis parallel to the center line of the concave hole 3, As a center, all the variable swirl vanes 18 rotate synchronously. A swirl blade drive device 19 is connected to the variable swirl blade 18, and the angle of the variable swirl blade 18 is adjusted by the swirl blade drive device 19. The swirl blade drive device 19 has a control unit 21. The drive is controlled by.

  A large number of auxiliary combustion air supply holes 22 having a small diameter are provided in the lower half of the burner chamber 6 (a positive pressure region to be described later) around the pulverized coal mixed flow jet pipe 9 at the bottom 8. A part of the combustion air 10 is supplied into the burner chamber 6 as auxiliary combustion air 23 from the periphery of the pulverized coal mixed flow jet pipe 9 through the auxiliary combustion air supply hole 22.

  The bottom portion 8 is provided with two flow rate adjusting plates 25, 25 via a rotating shaft 24. The flow rate adjusting plates 25, 25 rotate slidably on the outer surface of the base end of the bottom portion 8. The flow rate adjusting plates 25, 25 rotate synchronously so as to approach and separate from each other, and the auxiliary combustion air supply hole 22 can be opened and closed. The flow rate adjusting plates 25 and 25 are formed with semicircular relief portions 26 and 26, respectively, and in the fully closed state (see FIG. 2B), all the auxiliary combustion air supply holes 22 are formed. In addition to being blocked, the flow rate adjusting plates 25, 25 are prevented from interfering with the pulverized coal mixed flow jet pipe 9 by the escape portions 26, 26.

  When the flow rate adjusting plates 25, 25 are fully opened (see FIG. 2A), the flow rate adjusting plates 25, 25 are in contact with the tertiary air ejection pipe 12, and the auxiliary combustion air is used. All the supply holes 22 are opened. In the fully open state, a relief portion may be formed so that the flow rate adjusting plates 25, 25 and the tertiary air ejection pipe 12 do not interfere with each other.

  A flow rate adjusting plate driving device 27 is connected to the flow rate adjusting plates 25, 25, and a rotation angle of the flow rate adjusting plates 25, 25 is adjusted by the flow rate adjusting plate driving device 27. The driving of the plate driving device 27 is controlled by the control unit 21. By controlling the rotation of the flow rate adjusting plates 25, 25, the number of the auxiliary combustion air supply holes 22 closed by the flow rate adjusting plates 25, 25 is adjusted and supplied into the burner chamber 6. The flow rate of the auxiliary combustion air 23 is adjusted.

  The pulverized coal mixed flow ejection pipe 9 is connected to a pulverized coal mill 28, and the pulverized coal mill 28 supplies the pulverized mixed pulverized coal together with primary air to the pulverized coal mixed flow ejection pipe 9, and is controlled by the control unit 21. By controlling the operating state of the pulverized coal mill 28, the supply stop of the pulverized coal mixed flow 11 is controlled.

  The mixed pulverized coal may be temporarily stored in a pulverized coal bottle, and a fixed amount may be cut out by a feeder or the like and conveyed. In this case, a pulverized coal transport pipe (not shown) from the feeder is connected to the pulverized coal mixed flow jet pipe 9.

  The tertiary air ejection pipe 12 is connected to a combustion air supply source (not shown) via an air flow rate adjusting unit 29, and the control unit 21 controls the air flow rate adjusting unit 29 to control the tertiary air ejection. The flow rate of the temperature adjusting air 13 ejected from the pipe 12 is controlled.

  Hereinafter, the operation of the burner 1 will be described.

  First, the angle of the variable swirl vane 18 is adjusted by the swirl vane drive device 19, and the combustion air 10 given a predetermined swirl flow is ejected from the secondary air ejection part 14, and anthracite and The pulverized coal mixed stream 11 in which mixed pulverized coal composed of bituminous coal and primary air are mixed is ejected from the pulverized coal mixed stream ejection pipe 9.

  At this time, since the pulverized coal mixed flow jet pipe 9 is ejected from an eccentric portion inside the burner chamber 6, the burner chamber 6 provided with the pulverized coal mixed flow jet pipe 9 is provided in the burner chamber 6. 1 is a positive pressure, and the upper half of the burner chamber 6 provided with the tertiary air ejection pipe 12 (the upper side with respect to the paper surface in FIG. 1) is negative. Pressure. Accordingly, a positive pressure region is formed in the burner chamber 6 along the pulverized coal mixed flow 11, and a negative pressure region is formed on the opposite side of the pulverized coal mixed flow 11. By forming a negative pressure region in the burner chamber 6, high-temperature exhaust gas in the furnace is attracted to the burner chamber 6, and an internal circulation flow 31 is generated.

  The internal circulated flow 31 heats the mixed pulverized coal in the pulverized coal mixed flow 11, promotes the generation of volatile matter, forms a flame, and the mixed pulverized coal self-combusts (steady combustion).

  Here, since anthracite coal and subbituminous coal have different combustibility, oxygen in the burner chamber 6 may be consumed by the previously burnt subbituminous coal, and oxygen for burning the anthracite coal may be insufficient.

  In this embodiment, the auxiliary combustion air 23 is jetted into the burner chamber 6 from the periphery of the pulverized coal mixed flow jet pipe 9 in the axial direction through the auxiliary combustion air supply hole 22. By doing so, oxygen sufficient for the combustion of anthracite coal can be supplied into the burner chamber 6, and the mixed pulverized coal with a low volatile content can be reliably burned.

  The flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 is appropriately adjusted according to the type and combustion state of the mixed pulverized coal, and is determined by the oxygen in the pulverized coal mixed stream 11. If the mixed pulverized coal can be burned, the flow rate adjusting plates 25 and 25 may be fully closed, and the auxiliary combustion air 23 need not be supplied.

  Further, when the temperature in the burner chamber 6 becomes too high during the combustion of the burner 1, the temperature adjusting air 13 is supplied from the tertiary air ejection pipe 12 into the burner chamber 6. By supplying the temperature adjusting air 13 into the burner chamber 6, the inside of the burner chamber 6 is cooled, and the action of pushing the internal circulation flow 31 to the inside of the furnace occurs. The amount of exhaust gas attracted can be reduced, and the temperature in the burner chamber 6 can be lowered.

  As described above, in the first embodiment, the auxiliary combustion air 23 is supplied into the burner chamber 6 through the auxiliary combustion air supply hole 22, and the oxygen concentration in the burner chamber 6 is increased. Therefore, sufficient oxygen can be supplied even to anthracite burned later than sub-bituminous coal, and the combustibility of mixed pulverized coal mixed with low volatile fuel such as anthracite coal can be improved. Can do.

  Further, the auxiliary combustion air supply hole 22 is provided on the positive pressure region side of the bottom 8, and the axial direction from the periphery of the pulverized coal mixed flow jet pipe 9, that is, the positive pressure region in the burner chamber 6. The auxiliary combustion air 23 is supplied. Accordingly, the auxiliary combustion air 23 is not supplied to the negative pressure region in the burner chamber 6 and the circulation of the internal circulation flow 31 is not hindered. Flame stability can be improved.

  In addition, since the auxiliary combustion air supply holes 22 having a small diameter are provided, the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 through one auxiliary combustion air supply hole 22 is set. It can suppress, the influence on the said internal circulation flow 31 can be suppressed, and the ignition stability of mixed pulverized coal and the stability of the flame formed can be improved.

  Further, the flow rate adjusting plates 25, 25 are slidably provided on the base end side surface of the bottom portion 8, and the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 by the flow rate adjusting plates 25, 25 is adjusted. Since it can be adjusted, the oxygen concentration in the burner chamber 6 can be set to a concentration suitable for the combustion of the mixed pulverized coal, and the ignition stability of the mixed pulverized coal and the stability of the flame formed can be improved. it can.

  In the first embodiment, the auxiliary combustion air supply hole 22 is opened and closed by rotating the flow rate adjusting plates 25, 25 via the rotary shaft 24, but the flow rate adjusting plates 25, 25 For example, the auxiliary combustion air supply hole 22 may be opened and closed by sliding the flow rate adjusting plates 25, 25.

  Next, a burner 1 according to a second embodiment of the present invention will be described with reference to FIGS. 3 and 4, the same components as those in FIGS. 1, 2 </ b> A and 2 </ b> B are denoted by the same reference numerals, and the description thereof is omitted.

  In the second embodiment, the peripheral surface of the burner chamber 6 on the positive pressure region side (downward with respect to the paper surface in FIG. 3) provided with the pulverized coal mixed flow jet pipe 9 is horizontally penetrated. A large number of auxiliary combustion air supply holes 32 are provided. It is desirable that the position of the auxiliary combustion air supply hole 32 in the axial direction is on the base end side of the burner chamber 6 such as a protruding portion protruding from the burner cover 5 to the base end side.

  One end of a pipe 33 having a guide channel 30 formed therein is connected to each of the auxiliary combustion air supply holes 32, and the auxiliary combustion air supply hole 32 and the guide channel 30 communicate with each other. . An auxiliary combustion air supply block 34 is connected to the other end of the pipe 33 so that a part of the combustion air 10 is supplied to the auxiliary combustion air supply block 34. An auxiliary combustion air flow rate adjustment unit 35 is connected to the auxiliary combustion air supply block 34, and the control unit 21 controls the auxiliary combustion air flow rate adjustment unit 35 and supplies it to the auxiliary combustion air supply block 34. The flow rate of the combustion air 10 is controlled.

  The combustion air 10 supplied to the auxiliary combustion air supply block 34 is deflected in the horizontal direction by the guide flow path 30, and is then used as the auxiliary combustion air 23 from the auxiliary combustion air supply hole 32. It is supplied into the chamber 6.

  At this time, the auxiliary combustion air supply hole 32 is provided on the positive pressure region side of the burner chamber 6 and penetrates the peripheral surface of the burner chamber 6 in the horizontal direction. The auxiliary combustion air 23 deflected in the horizontal direction is ejected in the horizontal direction with respect to the positive pressure region in the burner chamber 6.

  Also in the second embodiment, the auxiliary combustion air 23 is supplied into the burner chamber 6 through the auxiliary combustion air supply hole 32, and the oxygen concentration in the burner chamber 6 is increased. Sufficient oxygen can be supplied to anthracite burned later than sub-bituminous coal for steady combustion, improving the combustibility of mixed pulverized coal in which low-volatile fuel such as anthracite and sub-bituminous coal are mixed. Can be made.

  Further, since the auxiliary combustion air supply hole 32 is provided on the positive pressure region side and is penetrated in the horizontal direction from the peripheral surface of the burner chamber 6, The deflected auxiliary combustion air 23 is supplied only to the positive pressure region in the burner chamber 6, and the auxiliary combustion air 23 is not supplied to the negative pressure region. Therefore, the circulation of the internal circulation flow 31 is not hindered by the auxiliary combustion air 23, and the ignition stability of the mixed pulverized coal and the stability of the formed flame can be improved.

  Further, since the auxiliary combustion air supply holes 32 having a small diameter are provided, the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 from one auxiliary combustion air supply hole 32 is set. It can suppress, the influence on the said internal circulation flow 31 can be suppressed, and the ignition stability of mixed pulverized coal and the stability of the flame formed can be improved.

  Next, a third embodiment of the present invention will be described with reference to FIGS. 5 and 6, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In the third embodiment, the circumferential surface of the burner chamber 6 on the positive pressure region side (lower side with respect to the paper surface in FIG. 5) provided with the pulverized coal mixed flow jet pipe 9 is horizontally penetrated. A number of auxiliary combustion air supply holes 36 are provided. The position of the auxiliary combustion air supply hole 36 in the axial direction is provided on the tip side of the burner cover 5, that is, in the secondary air conduction path 17.

  On the outer peripheral surface of the burner chamber 6, auxiliary combustion air guide blocks 38, 38 having guide passages 37 formed in the horizontal direction are attached at two positions facing each other on the positive pressure region side, and the auxiliary combustion is performed. The air supply hole 36 and the guide channel 37 communicate with each other. The secondary air conduction path 17 and the burner chamber 6 communicate with each other through the auxiliary combustion air supply hole 36 and the guide flow path 37, and the combustion air 10 flowing through the secondary air conduction path 17. Is partially deflected in the horizontal direction by the guide flow path 37 and then supplied as auxiliary combustion air 23 into the burner chamber 6.

  The auxiliary combustion air guide blocks 38, 38 are provided with open / close shutters 39, 39, respectively, and the open / close shutters 39, 39 slide vertically along the auxiliary combustion air guide blocks 38, 38. It is free. The opening / closing shutters 39, 39 slide in synchronization with each other, and the guide channel 37 can be opened / closed by the opening / closing shutters 39, 39.

  A driving device (not shown) is connected to the opening / closing shutters 39, 39, and the guides closed by the opening / closing shutters 39, 39 when the opening / closing shutters 39, 39 are slid vertically by the driving device. The number of the flow paths 37 is adjusted, and the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 is adjusted.

  Also in the third embodiment, the auxiliary combustion air 23 is supplied into the burner chamber 6 through the auxiliary combustion air supply hole 36 to increase the oxygen concentration in the burner chamber 6. Sufficient oxygen can be supplied to anthracite burned later than sub-bituminous coal for steady combustion, improving the combustibility of mixed pulverized coal in which low-volatile fuel such as anthracite and sub-bituminous coal are mixed. Can be made.

  Further, in the third embodiment, the combustion air 10 flowing through the secondary air conduction path 17 is swirled by the variable swirl vane 18 but is provided on the positive pressure region side of the burner chamber 6. The auxiliary combustion air supply hole 36 penetrating the burner chamber 6 in the horizontal direction communicates with the guide flow path 37 formed in the horizontal direction. As a result, the combustion air 10 is deflected to the guide flow path 37, and the auxiliary combustion air 23 is supplied in a horizontal direction to the positive pressure region in the burner chamber 6 from the auxiliary combustion air supply hole 36. Is done.

  Therefore, since the auxiliary combustion air 23 is supplied only to the positive pressure region in the burner chamber 6 and not to the negative pressure region, the auxiliary combustion air 23 circulates the internal circulation flow 31. Without being hindered, the ignition stability of the mixed pulverized coal and the stability of the flame formed can be improved.

  Further, since the auxiliary combustion air supply holes 36 having a small diameter are provided, the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 from one auxiliary combustion air supply hole 36 is set. It can suppress, the influence on the said internal circulation flow 31 can be suppressed, and the ignition stability of mixed pulverized coal and the stability of the flame formed can be improved.

  The opening / closing shutters 39, 39 are slidably provided in the auxiliary combustion air guide blocks 38, 38, and the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 by the opening / closing shutters 39, 39. Since the oxygen concentration in the burner chamber 6 can be adjusted to a concentration suitable for the combustion of the mixed pulverized coal, the ignition stability of the mixed pulverized coal and the stability of the formed flame can be improved. Can do.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. 7 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  In the fourth embodiment, an auxiliary combustion air supply hole 41 is provided on the positive pressure region side (downward with respect to the paper surface in FIG. 7) where the pulverized coal mixed flow jet pipe 9 of the burner chamber 6 is provided. ing. The position of the auxiliary combustion air supply hole 41 in the axial direction is provided at the front end side of the burner cover 5, that is, in the secondary air conduction path 17, and the auxiliary combustion air supply hole 41 passes through the auxiliary combustion air supply hole 41. A part of the combustion air 10 flowing in the secondary air conduction path 17 is supplied into the burner chamber 6 as auxiliary combustion air 23.

  The burner chamber 6 is provided with a cylindrical opening / closing member 43 that freely slides in the axial direction on the outer peripheral surface of the burner chamber 6 via a drive cylinder 42. The auxiliary combustion air supply hole 41 can be opened and closed by the opening / closing member 43, and the opening degree of the auxiliary combustion air supply hole 41 is adjusted by the opening / closing member 43. The flow rate of the supplied auxiliary combustion air 23 is adjusted.

  Also in the fourth embodiment, the auxiliary combustion air 23 is supplied into the burner chamber 6 through the auxiliary combustion air supply hole 41, and the oxygen concentration in the burner chamber 6 is increased. Sufficient oxygen can be supplied to anthracite burned later than sub-bituminous coal for steady combustion, improving the combustibility of mixed pulverized coal in which low-volatile fuel such as anthracite and sub-bituminous coal are mixed. Can be made.

  Further, the opening / closing member 43 slidable in the axial direction on the outer peripheral surface of the burner chamber 6 is provided, and the flow rate of the auxiliary combustion air 23 supplied into the burner chamber 6 can be adjusted by the opening / closing member 43. Therefore, the oxygen concentration in the burner chamber 6 can be set to a concentration suitable for the combustion of the mixed pulverized coal, and the ignition stability of the mixed pulverized coal and the stability of the flame formed can be improved.

  In the first to fourth embodiments, a part of the combustion air 10 is extracted and supplied as the auxiliary combustion air 23 into the burner chamber 6. It goes without saying that a part of the air 13 may be extracted and supplied as the auxiliary combustion air 23 into the burner chamber 6.

DESCRIPTION OF SYMBOLS 1 Burner 2 Furnace wall 3 Concave hole 6 Burner chamber 9 Pulverized coal mixed flow jet pipe 10 Combustion air 11 Pulverized coal mixed flow 12 Tertiary air jet pipe 13 Temperature control air 14 Secondary air jet part 21 Control part 22 Auxiliary combustion Air supply hole 23 Auxiliary combustion air 25 Flow rate adjustment plate 27 Flow rate adjustment plate drive device 29 Air flow rate adjustment unit 30 Guide flow path 31 Internal circulation flow 32 Auxiliary combustion air supply hole 34 Auxiliary combustion air supply block 35 Auxiliary combustion Air flow rate adjusting unit 36 Auxiliary combustion air supply hole 37 Guide flow path 38 Auxiliary combustion air guide block 39 Opening and closing shutter 41 Auxiliary combustion air supply hole 43 Opening and closing member

Claims (8)

A concave hole formed in the wall of the furnace, a bottomed cylindrical burner chamber disposed concentrically with the concave hole and provided with an auxiliary combustion air supply hole at the core-side tip, and at the bottom of the burner chamber A pulverized coal mixed flow jet pipe that opens to an eccentric position and ejects a pulverized coal mixed flow, and an opening that is eccentric to the opposite side with respect to the axis of the pulverized coal mixed flow jet pipe and the burner chamber at the bottom of the burner chamber and comprising the tertiary air jet pipe for jetting temperature adjusting air, a secondary air injection portion of the ring-shaped space is formed for ejecting combustion air to between said burner chamber recessed hole, the pulverized The pulverized coal mixed flow is ejected from the coal mixed flow ejection pipe, thereby forming a positive pressure region in the burner chamber along the pulverized coal mixed flow, and a negative pressure region on the opposite side of the pulverized coal mixed flow. The auxiliary combustion air supply is formed The positive pressure provided frequency side, the burner being characterized in that to enable the supply part of the combustion air into said positive pressure region than the auxiliary combustion air supply holes. The burner according to claim 1 , wherein a plurality of small-diameter auxiliary combustion air supply holes are provided in the burner chamber. It said auxiliary combustion air supply hole is provided in the bottom portion, burner of claim 1 or claim 2 complement are co combustion air supplied to the axial direction of the burner chamber. 4. The burner according to claim 3 , further comprising a flow rate adjusting plate slidably provided on a base end outer surface of the bottom portion, wherein the auxiliary combustion air supply hole can be opened and closed by sliding of the flow rate adjusting plate. A concave hole formed in the wall of the furnace, a bottomed cylindrical burner chamber disposed concentrically with the concave hole and provided with an auxiliary combustion air supply hole at the core-side tip, and at the bottom of the burner chamber A pulverized coal mixed flow jet pipe that opens to an eccentric position and ejects a pulverized coal mixed flow, and an opening that is eccentric to the opposite side with respect to the axis of the pulverized coal mixed flow jet pipe and the burner chamber at the bottom of the burner chamber and comprising the tertiary air jet pipe for jetting temperature adjusting air, a secondary air injection portion of the ring-shaped space is formed for ejecting combustion air to between said burner chamber recessed hole, said auxiliary Combustion air supply holes are provided horizontally through the peripheral surface of the burner chamber, and a part of the combustion air can be supplied horizontally into the burner chamber from the auxiliary combustion air supply holes. Burner featuring The burner according to claim 5 , further comprising a guide channel for deflecting the combustion air in a horizontal direction, the guide channel communicating with the auxiliary combustion air supply hole. The auxiliary combustion air guide block in which the guide flow path is formed, and an open / close shutter slidably provided on the auxiliary combustion air guide block, and the guide flow path is formed by sliding the open / close shutter. The burner according to claim 6 , which can be opened and closed. A concave hole formed in the wall of the furnace, a bottomed cylindrical burner chamber disposed concentrically with the concave hole and provided with an auxiliary combustion air supply hole at the core-side tip, and at the bottom of the burner chamber A pulverized coal mixed flow jet pipe that opens to an eccentric position and ejects a pulverized coal mixed flow, and an opening that is eccentric to the opposite side with respect to the axis of the pulverized coal mixed flow jet pipe and the burner chamber at the bottom of the burner chamber A tertiary air jet pipe for jetting temperature adjusting air, a secondary air jet part of a ring-shaped space that is formed between the burner chamber and the concave hole and jets combustion air, and a periphery of the burner chamber ; and a cylindrical closing member provided slidably in the axial direction of the plane, a portion of the combustion air to be supplied from the auxiliary combustion air supply holes into the burner chamber, the opening and closing Said auxiliary by sliding of member Burner, characterized in that the tempering air supply holes can be opened and closed.

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