JP5281806B2 - Wood pellet combustion equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain combustion ash from depositing on a combustion floor, without stopping a combustor. <P>SOLUTION: An ash flying pipe 38 connected to an air compressor 48 and a nozzle 40 turning in the combustion floor 16 direction, are arranged in a refractory wall 19. The combustion ash depositing on the combustion floor 16 is intermittently blown off by high pressure air coming out of the air compressor 48, and is discharged outside a combustion chamber 2 by being accompanied by combustion exhaust gas. As a result of it, a quantity of combustion ash depositing on the combustion floor 16 can be reduced, and combustion failure of a woody pellet can be prevented. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a wood pellet combustion apparatus used as a heating source such as hot water or a steam boiler, a high-temperature regenerator of an absorption chiller / heater.

  Conventionally, high-quality fuels such as gas and oil have been used for heating sources such as hot water or steam boilers and high-temperature regenerators of absorption chiller / heaters. However, in recent years, biomass fuel has come to be used from the viewpoint of effective use of resources and protection of the global environment, and in particular, wood pellets made from pellets of sawdust and wood waste have been used as woody biomass fuel. Yes. As an apparatus for burning wood pellets, for example, one described in Patent Document 1 is known.

  By the way, when wood pellets are burned, a lot of combustion ash is generated. However, in Patent Document 1, a ceramic layer formed by laminating a large number of ceramic particles is provided in a furnace forming a combustion chamber to form a combustion bed. The pellets are dispersed and burned while flowing with the primary air supplied from below the ceramic layer so that the combustion ash is scattered outside the combustion furnace.

JP 2006-275301 A

  However, Patent Document 1 has a problem that the primary air alone does not have enough wind power, and a large amount of combustion ash remains on the combustion bed and accumulates. If combustion ash accumulates, it will make the passage of primary air worse and it will cause the combustion failure and ignition failure of a wood pellet. Further, when the accumulated combustion ash is heated and melted, a clinker which is a solid solid is generated, and therefore, combustion failure is more likely to occur. For this reason, for example, it becomes necessary to scrape the combustion ash manually or to remove the clinker. Moreover, when performing a removal operation | work, it is necessary to stop a combustion apparatus, and the problem that driving | operation efficiency worsens also arises.

  The problem to be solved by the present invention is to suppress the accumulation of combustion ash on the combustion bed without stopping the combustion apparatus.

  In order to solve the above problems, the wood pellet combustion apparatus of the present invention supplies a cylindrical combustion chamber, a combustion bed provided in the combustion chamber and formed with a large number of vent holes, and air to the lower surface side of the combustion bed. A plurality of nozzles for intermittently injecting air onto the upper surface of the combustion bed in a wood pellet combustion apparatus comprising an air flow path to supply, a supply port for supplying wood pellets to the combustion bed, and an induction blower for attracting combustion exhaust gas Is provided.

  According to the present invention, the combustion ash deposited on the combustion bed is intermittently blown off by the air ejected from the plurality of nozzles, and is discharged outside the combustion chamber along with the combustion exhaust gas. As a result, the amount of combustion ash that accumulates on the combustion bed can be reduced, and poor combustion of the wood pellets can be prevented. Moreover, the frequency which stops a combustion apparatus for combustion ash removal work can be reduced.

  The combustion chamber includes a double cylindrical primary combustion chamber and a cylindrical secondary combustion chamber connected to the primary combustion chamber, and secondary combustion is performed between the double cylinders of the primary combustion chamber. An air flow path for supplying air to the chamber may be used. Thereby, the secondary air supplied to the secondary combustion chamber can be warmed by the residual heat of the primary combustion chamber, and combustion in the secondary combustion chamber can be promoted.

  Further, in this case, the combustion chambers are arranged horizontally, pipes are provided on both sides of the combustion bed in parallel with the axial direction of the combustion chambers, the pipes communicate with the air compressor, and a plurality of nozzles are connected to the pipes. In addition, it may be configured to be provided toward the combustion bed at regular intervals in the axial direction. According to this, the high pressure air which came out of the air compressor blows off the combustion ash deposited on the combustion bed by ejecting from the nozzle through the pipe line. The interval at which high-pressure air is emitted is preferably set according to the amount of combustion ash generated. For example, it is set as 1 second once every 5 minutes. The number of nozzles is preferably increased or decreased according to the amount of combustion ash and the pressure of high-pressure air. In addition to the pipe line, a central nozzle communicated with the air compressor can be provided at the upstream end of the combustion bed toward the combustion bed. Thereby, it becomes easy to blow off the combustion ash from the upstream side to the downstream side.

  It is also possible to provide fire walls on both sides of the combustion bed in parallel with the axial direction of the combustion chamber, and to provide pipes and nozzles penetrating into the fire wall. Thereby, a pipe line and a nozzle can be protected from combustion heat. It is also possible to provide a space around the pipe line in the refractory wall and communicate with the air flow path so that the air flows through the gap between the nozzle and the refractory wall to cool the nozzle. It is also possible to provide a pipe line outside the refractory wall and to cool the pipe by constantly flowing a small amount of air separately from the high-pressure air.

  It is also possible to install the nozzles on both sides of the combustion bed toward the downstream side of the combustion chamber. Thereby, the blown-off combustion ash can be easily flowed to the downstream side of the combustion chamber. Furthermore, by disposing the nozzles in a zigzag manner while shifting the positions in the axial direction, the combustion ash deposited on the combustion bed can be blown off more effectively.

  Further, the combustion bed can be configured by any one of a metal plate, a ceramic plate, and a combination of a metal plate and a ceramic plate in which a large number of air holes are formed. Thereby, the heat resistance of a combustion bed improves.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that combustion ash accumulates on a combustion bed, without stopping a combustion apparatus.

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

  With reference to FIG. 1 thru | or 3, the structure of the wood pellet combustion apparatus 1 of a present Example is demonstrated. 1 is a side sectional view of the wood pellet combustion apparatus 1, FIG. 2 (a) is a plan sectional view of the wood pellet combustion apparatus 1, and FIG. 2 (b) is a line (AA) in FIG. 1 is a cross-sectional view of a wood pellet combustion apparatus 1. In addition, the circumference | surroundings of the combustion bed 16 and the nozzle 40 of Fig.2 (a) are the cross sections in the line (BB) of FIG.2 (b).

  As shown in the figure, the cylindrical combustion chamber 2 is composed of a primary combustion chamber 4 and a secondary combustion chamber 6. The primary combustion chamber 4 includes a coaxial outer cylinder 8 and an inner cylinder 10 arranged in a horizontal shape, and a downstream end is connected to the secondary combustion chamber 6. The secondary combustion chamber 6 is composed of a small-diameter cylinder 12 coaxial with the primary combustion chamber 4. Although the downstream end of the secondary combustion chamber 6 is not shown, for example, combustion exhaust gas is passed through a cyclone or the like. Communicating with an attracting blower.

  At the center bottom of the inner cylinder 10 of the primary combustion chamber 4, a metal flat combustion bed 16 having a large number of vent holes is provided up to the vicinity of the downstream end of the primary combustion chamber 4. . A rectangular weir 18 formed of a refractory is provided at the downstream end of the combustion bed 16 to prevent the wood pellets from rolling down. Fire walls 19 are provided on both sides of the combustion bed 16 along the axial direction of the primary combustion chamber 4, and the fire walls 19 are formed of casters made of heat-resistant concrete. The refractory wall 19 includes a slope toward the combustion bed 16 so that the wood pellets can easily roll down to the combustion bed 16.

  An air flow path 20 that supplies primary air to the lower surface side of the combustion bed 16 is provided below the combustion bed 16. The upstream end of the air flow path 20 is connected to a wind box 28, and a blower 30 is connected to the wind box 28.

  A space between the outer cylinder 8 and the inner cylinder 10 above the combustion bed 16 serves as a secondary air flow path 26 for supplying secondary air to the secondary combustion chamber 6, and an air flow path below the combustion bed 16. Reference numeral 20 also serves as a flow path for primary air and secondary air. The upstream end of the secondary air flow path 26 is connected to the wind box 28, and the secondary air flow path 26 is communicated with the air flow path 20 via the wind box 28. That is, the blower 30 supplies primary air and secondary air to the air flow path 20 and the secondary air flow path 26.

  In the upper part of the upstream end of the primary combustion chamber 4, a pellet supply port 32 that supplies wood pellets to the combustion bed 16 is provided. A starting burner storage cylinder 34 is provided below the pellet supply port 32, and a starting burner 36 is stored therein. The starter burner storage cylinder 34 is provided with an ignition blower 24. The ignition blower 24 sends air to the starter burner storage cylinder 34 at the time of ignition.

  Here, the ash blower according to the feature of the present embodiment will be described. The ash blow-off device includes two stainless steel ash blow-off pipes 38, a plurality of nozzles 40 provided on the ash blow-off pipe 38, a central nozzle 42, a solenoid valve 46, and an air compressor 48. Is done.

  The ash blowing pipe 38 is disposed in a space 50 that penetrates to the downstream end along the axial direction of the primary combustion chamber 4 provided in the fire walls 19 on both the left and right sides of the combustion bed 16. The nozzles 40 are provided on the ash blow-off pipe 38 at regular intervals in the axial direction and are directed toward the combustion bed 16. The nozzle 40 is disposed in the through hole 52 in the direction of the combustion bed 16 orthogonal to the space 50 provided in the fireproof wall 18.

  Clearances are formed between the ash blowing pipe 38 and the space 50 and between the nozzle 40 and the through hole 52. Air from the air flow path 20 flows through the gap between the nozzle 40 and the through hole 52 so that the nozzle 40 can be cooled. The air that has flowed through the gap flows into the primary combustion chamber 4.

  The central nozzle 42 is inserted from the opening at the bottom of the starter burner storage cylinder 34 and is disposed at the bottom of the starter burner storage cylinder 34. The two ash blow-off pipes 38 and the central nozzle 42 are connected to one pipe at the base end, and are connected to an air compressor 48 via an electromagnetic valve 46.

  Here, the operation of the present embodiment will be described with reference to FIG. 3 (a) is a plan sectional view of the wood pellet combustion apparatus 1, and FIG. 3 (b) is a sectional view of the wood pellet combustion apparatus 1 along the line (CC) in FIG. Indicates the flow of high-pressure air. The wood pellets supplied from the pellet supply port 32 fall on the combustion bed 16. Here, the starting burner 36 is ignited to burn the wood pellets. When the wooden pellets start to self-combust, the starting burner 36 is stopped.

  The wood pellets are combusted while volatilizing moisture and volatile components by the primary air supplied from the blower 30 to the lower surface side of the combustion bed 16 through the wind box 28 and the air flow path 20. A part of the combustion ash generated at this time rises by the primary air and is discharged from the secondary combustion chamber 6 to the outside of the combustion chamber 2 along with the combustion exhaust gas, but the rest is deposited on the combustion bed 16. Further, the unburned portion of the combustion gas generated at this time flows into the secondary combustion chamber 6 and is supplied from the blower 30 to the secondary combustion chamber 6 through the wind box 28, the air flow path 20 and the secondary air flow path 26. Combusted by the secondary air generated. The combustion exhaust gas generated at this time is attracted by an attracting blower (not shown).

  Here, operation | movement of the ash blowing apparatus of a present Example is demonstrated. First, the time interval at which the electromagnetic valve 46 is opened and closed is set, and the time interval at which the ash blowing device emits high-pressure air is set. The time interval is set according to the amount of generated combustion ash, but here, it is set to 1 second once every 5 minutes.

  The high-pressure air exiting from the air compressor 48 flows through the ash blow-off pipe 38 and is ejected from the nozzle 40 toward the combustion bed 16 in the direction of the arrow in FIG. High pressure air is also ejected from the central nozzle 42 in the direction of the arrow. The accumulated combustion ash is blown off by the high-pressure air and rises into the primary combustion chamber 4. The soared combustion ash flows with the combustion exhaust gas into the secondary combustion chamber 6 and is further attracted and discharged out of the combustion chamber 2 by an attraction blower (not shown).

  As described above, according to the present embodiment, the high pressure air of the ash blowing apparatus comprising the ash blowing pipe 38, the plurality of nozzles 40, the central nozzle 42, the electromagnetic valve 46, and the air compressor 48 is used. Combustion ash deposited on the combustion bed 16 is intermittently blown off and discharged to the outside of the combustion chamber 2 along with the combustion exhaust gas. As a result, the amount of combustion ash deposited on the combustion bed 16 can be reduced, and poor combustion of the wood pellets can be prevented. Moreover, the frequency which stops the wood pellet combustion apparatus 1 for a combustion ash removal operation | work can be reduced.

  Further, since the air flow path 20 and the secondary air flow path 26 for supplying the secondary air to the secondary combustion chamber 6 are formed between the outer cylinder 8 and the inner cylinder 10 of the primary combustion chamber 4, the secondary air is It can be warmed by the residual heat of the primary combustion chamber 4, and the combustion in the secondary combustion chamber 6 can be promoted.

  Further, since the ash blower pipe 38 and the nozzle 40 are arranged in the fireproof wall 19, the ash blower pipe 38 and the nozzle 40 can be protected from the combustion heat. Further, since a gap is provided around the ash blowing pipe 38 and the nozzle 40 in the fire wall 19 and communicated with the air flow path 20, air flows through the gap between the nozzle 40 and the fire wall 19. Can be cooled.

  Example 2 will be described with reference to FIG. In the present embodiment, the ash blow-off pipe 38 is disposed on the fire wall 19. Further, the ash blow-off pipe 38 is provided with a hole through which high-pressure air is ejected instead of the nozzle 40. In addition to the high-pressure air, a small amount of air always flows through the ash blow-off pipe 38 for cooling. Other configurations are the same as those in the first embodiment.

  According to this embodiment, it is not necessary to provide the spaces 50 and 52 in the fire wall 19.

  Example 3 will be described with reference to FIG. In the present embodiment, the nozzle 40 is provided toward the downstream side of the primary combustion chamber 4. Other configurations are the same as those in the first embodiment. Here, the fireproof wall 19 is not provided, but may be provided.

  According to the present embodiment, the blown-off combustion ash can easily flow to the downstream side of the combustion chamber 2.

  Example 4 will be described with reference to FIG. In the present embodiment, the nozzles 40 are arranged in a staggered manner while being displaced from each other in the axial direction of the combustion chamber 2. Other configurations are the same as those in the first embodiment. Here, the fireproof wall 19 is not provided, but may be provided.

  According to the present embodiment, the combustion ash deposited on the combustion bed 16 can be blown off more effectively.

  In the first to fourth embodiments, the case where the cylindrical combustion chamber 2 is arranged in a horizontal shape has been described, but it may be arranged in a vertical shape. In this case, the ash blowing pipe 38 is preferably provided in parallel to an axis perpendicular to the axial direction of the combustion chamber 2, but the installation direction is not limited as long as the combustion ash deposited on the combustion bed 16 can be blown off. .

  Further, the installation location of the ash blowing pipe 38 is not limited to both sides of the combustion bed 16 and may be appropriately installed in a location where the combustion ash in the combustion chamber 2 is likely to accumulate.

  Further, the primary combustion chamber 4 and the secondary combustion chamber 6 are not limited to a cylindrical shape, and may be configured to have a rectangular cross section. Further, although the combustion bed 16 is made of metal, it can be made of ceramic or a combination of metal and ceramic. The ash blow-off pipe 38 is not limited to stainless steel but may be made of a metal having heat resistance.

It is a sectional side view of a wood pellet combustion apparatus. (A) is a cross-sectional plan view of the wood pellet combustion apparatus, and (b) is a cross-sectional view of the wood pellet combustion apparatus taken along line (AA). (A) is a plane sectional view of a wood pellet combustion apparatus when high-pressure air is ejected, and (b) is a cross-sectional view of the wood pellet combustion apparatus taken along line (BB). (A) is sectional drawing of the wood pellet combustion apparatus of Example 2, (b) is a plane sectional view of the wood pellet combustion apparatus of Example 3. FIG. It is a plane sectional view of the wood pellet combustion apparatus of Example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wood pellet combustion apparatus 2 Combustion chamber 4 Primary combustion chamber 6 Secondary combustion chamber 16 Combustion bed 20 Air flow path 26 Secondary air flow path 28 Wind box 38 Ash blow-off pipe 40 Nozzle 42 Central nozzle 48 Air compressor

Claims (9)

A cylindrical combustion chamber, a combustion bed provided in the combustion chamber and formed with a large number of vent holes, an air flow path for supplying air to the lower surface side of the combustion bed, and supplying wood pellets to the combustion bed In a wood pellet combustion apparatus equipped with a supply port and an induction blower for attracting combustion exhaust gas,
A wood pellet combustion apparatus , wherein a plurality of nozzles for intermittently ejecting air to the upper surface of the combustion bed are provided on both sides of the upper surface of the combustion bed toward the combustion bed . In claim 1,
The combustion chamber includes a double cylindrical primary combustion chamber and a cylindrical secondary combustion chamber connected to the primary combustion chamber, and the secondary cylinder is disposed between the secondary cylinders of the primary combustion chamber. A wood pellet combustion apparatus characterized in that it is an air flow path for supplying air to a combustion chamber. In claim 1 or 2,
The combustion chambers are arranged horizontally, pipes are provided on both sides of the combustion bed in parallel to the axial direction of the combustion chambers, the pipes communicate with an air compressor, and the plurality of nozzles are A wood pellet combustion apparatus characterized by being provided in a pipe line toward the combustion bed at regular intervals in the axial direction. In claim 3,
In addition to the pipe line, a wood pellet combustion apparatus, wherein a central nozzle communicated with the air compressor is provided at an upstream end portion of the combustion bed toward the combustion bed. In claim 3 or 4,
A wood pellet combustion apparatus, wherein fire walls are provided on both sides of the combustion bed in parallel with the axial direction of the combustion chamber, and the pipes and the nozzles are provided through the fire wall. In claim 3 or 4,
A wood pellet combustion apparatus, wherein fire walls are provided on both sides of the combustion bed parallel to the axial direction of the combustion chamber, and the pipes are provided outside the fire walls. In any one of Claims 3 thru | or 6,
The wood pellet combustion apparatus, wherein the nozzle is directed toward the downstream side of the combustion chamber. In any one of Claims 3 thru | or 6,
The wood pellet combustion apparatus according to claim 1, wherein the nozzles on both sides of the combustion bed are arranged in a staggered manner while being shifted from each other in the axial direction. In any one of Claims 1 thru | or 8,
The wood pellet combustion apparatus, wherein the combustion bed is one of a metal plate, a ceramic plate, and a combination of a metal plate and a ceramic plate in which a large number of air holes are formed.

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