JP2019002670A - Wood chip burning boiler, and trimmed branch burning plant using the same - Google Patents

Abstract

To provide a wood chip burning boiler capable of burning a wood chip generated by crushing trimmed branches, and a trimmed branch burning plant using the same.SOLUTION: A wood chip burning boiler according to the present invention includes: a furnace having a burning part, covered with a top panel with a fuel inlet opening, and for burning a wood chip introduced from the fuel inlet opening, and a retention part for temporally retaining exhaust gas generated in the burning part; a water reservoir, installed on the outer periphery of the furnace, and for storing water heated by heat radiated by the furnace; an air chamber, installed below the furnace, and for supplying the furnace with air for burning; a plurality of air supply pipes, extending from the air chamber to the inside of the furnace, and each bored with an air jet hole for jetting air supplied from the air chamber around.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wood chip combustion boiler and a pruning branch combustion plant using the same, and more particularly, a wood chip combustion boiler capable of incinerating wood chips generated by crushing a pruning branch and pruning branch combustion using the same. Regarding the plant.

In recent years, it has become difficult to process pruned branches resulting from pruning street trees planted in parks, roads, and the like.
If you ask the local government to dispose of it as general waste, you will need a disposal fee, so it is common to incinerate it with a dedicated incinerator.
However, when the pruned branches are burned as they are, it is necessary not only to prevent the generation of dioxins but also to consider noise, smoke emission, and ash treatment.
Therefore, a “waste treatment method” has been proposed in which pruned branches are crushed into wood chips to remove leaves and camellia and then subjected to floating combustion. (For example, Patent Document 1)

  The above-described treatment method can improve combustion efficiency by floatingly burning wood chips.

JP 2013-111568 A

  However, the waste disposal method according to the above proposal needs not only to remove leaves and grass from the crushed wood chips, but also to supply auxiliary fuel continuously when burning the wood chips. This is necessary and causes an increase in operating costs.

  The present invention has been made in view of the above problems, and an object thereof is to provide a wood chip combustion boiler capable of incinerating wood chips produced by crushing pruned branches and a pruned branch combustion plant using the same. And

  A wood chip combustion boiler according to the present invention includes a combustion section that is covered with a top plate that has a fuel input opening and burns wood chips that are input from the fuel input opening, and a retention section that temporarily retains exhaust gas generated in the combustion section. , A water tank that is installed on the outer periphery of the furnace and stores water heated by heat radiated from the furnace, an air chamber that is installed in the lower part of the furnace and supplies combustion air to the furnace, and the furnace from the air chamber And a plurality of air supply pipes each having a plurality of air ejection holes extending inward and ejecting air supplied from an air chamber.

  With this configuration, the wood chip can be burned at a low ashing rate.

  The wood chip combustion boiler according to the present invention includes a straight pipe type air supply pipe in which an air supply pipe extends straight upward from the air chamber, a straight pipe portion extending upward from the air chamber into the furnace, and a midway between the straight pipe portions. And a cruciform air supply pipe having a branch pipe extending horizontally in both directions and having a straight pipe part and an air ejection hole for ejecting air supplied from the air chamber around the branch pipe part.

  With this configuration, it is possible to reduce the ashing rate by burning the wood chips while floating in the furnace.

  The wood chip combustion boiler according to the present invention has a plurality of cruciform air supply pipes that are fewer than straight pipe air supply pipes.

  With this configuration, it is possible not only to float the wood chips on the entire furnace, but also to prevent the wood chips from being deposited on the bottom plate.

  The pruned branch combustion plant according to the present invention includes a crusher for crushing a pruned pruned branch into wood chips, a chip silo for temporarily storing wood chips crushed by the crusher, and wood stored in the chip silo. Wood chip combustion boiler for burning chips, exhaust gas cooler for water-cooling the exhaust gas discharged from the staying part of the wood chip combustion boiler, exhaust gas treatment facility for discharging the exhaust gas discharged from the exhaust gas cooler to the outside, and wood chip And hot water supply equipment that supplies hot water generated in a storage tank of a combustion boiler and hot water generated by exhaust gas in a gas cooler to the outside.

  With this configuration, it becomes possible not only to incinerate the pruned branches at a low ashing rate, but also to supply hot water to the outside.

  The pruned branch combustion plant according to the present invention includes a reflux path in which the exhaust gas treatment facility recirculates the exhaust gas cooled by the exhaust gas cooler to the chip silo in order to dry the wood chips.

  With this configuration, it is possible to further improve the thermal efficiency of the entire plant.

  The wood chip combustion boiler according to the present invention can incinerate wood chips to an ashing rate of about 0.3% without auxiliary combustion.

  Further, the pruned branch combustion plant according to the present invention can be incinerated to a ashing rate of about 0.3% by crushing pruned branches generated by pruning roadside trees into wood chips and burning them.

It is a three-sided view of a wood chep combustion boiler. It is a perspective view of a wood chep combustion boiler. It is a perspective view of a bottom plate and a combustion part. It is a three-sided view of a pruned branch combustion plant to which a wood chep combustion boiler is applied.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a three-sided view of a wood chep combustion boiler according to the present invention, and FIG. 2 is a perspective view of a wood chep combustion boiler.

That is, the wood chep combustion boiler 10 according to the present invention has a structure in which the boiler 11 and the cyclone 12 are integrally covered with the outer wall 13.
The boiler 11 is divided into an upper combustion chamber 15 and a lower air chamber 16 by a bottom plate 14.
The combustion chamber 15 is composed of a combustion part 151 in which the lower wood chip burns and a staying part 152 in which the upper exhaust gas stays.

  A plurality of (for example, 14) holes are perforated in the bottom plate 14 so that air is supplied from the air chamber 16 to the combustion chamber 15.

FIG. 3 is a perspective view of the bottom plate and the combustion part, and a plurality of (for example, 11) straight pipe air supply pipes 17a to 17k extending into the combustion part are inserted into the holes drilled in the bottom plate 14. Yes.
In addition, the upper end part of the straight pipe type air supply pipes 17a-17k shall be obstruct | occluded.
About 100 small holes are drilled in the peripheral walls of each of the straight pipe type air supply pipes 17a to 17k so that air is ejected into the combustion section.

Furthermore, the number of cross-shaped air supply pipes 18a to 18c (for example, three) fewer than the straight pipe type air supply pipes 17a to 17k is inserted into the holes drilled in the bottom plate 14.
It is assumed that the upper ends of the cruciform air supply pipes 18a to 18c and both ends of the horizontal pipe are also closed.
About 100 small holes are also perforated on the peripheral walls of the cruciform air supply pipes 18a to 18c, and air is ejected into the combustion section.

  The straight pipe-type air supply pipes 17a to 17k have a length that reaches substantially the upper end of the combustion section 151, and the cross-type air supply pipes 18a to 18c are approximately three minutes of the straight pipe-type air supply pipes 17a to 17k. It is desirable to have a length of one.

The staying part 152 and the cyclone 12 are connected by a duct 19 that guides the exhaust gas staying in the staying part 152 to the cyclone.
Moreover, the space between the outer side of the combustion chamber 11, the cyclone 12, and the duct 19 and the outer wall 13 functions as a water storage tank.

The upper part of the outer wall 13 is provided with a wood chip inlet 201 for supplying wood chips to the combustion part, an exhaust gas outlet 202 for discharging exhaust gas discharged from the cyclone, and a discharge port 203 for releasing steam to the atmosphere. 20.
Further, a water supply port 21 for supplying water to the water storage tank and a hot water outlet 22 for taking out hot water generated in the water storage tank are installed on the outer wall.

FIG. 4 is a three-side view of a pruned branch combustion plant to which the wood chep combustion boiler according to the present invention is applied.
That is, the pruned branch combustion plant 1 includes a belt conveyor 51, a crusher 52, a first slat conveyor 53, a wood chip silo 54, a second slat conveyor 55, a wood chip combustion boiler 10, an exhaust gas cooler 56, and a bug filter 57. And an exhaust gas treatment facility 58.

The pruned branches carried in by a truck or the like are conveyed to the upper hopper of the crusher 52 by the belt conveyor 51.
The pruned branch thrown into the upper hopper is crushed by the crusher 52 into wood chips of about 50 mm square and about 10 mm thick.

The wood chips generated by the crusher 52 are conveyed to the wood chip silo 54 by the first slat conveyor 53.
Wood chips are temporarily stored in the wood chip silo 54 for drying. The bottom surface of the wood chip silo 54 is a belt conveyor, and the wood chips introduced from the first slat conveyor 53 are directed toward the second slat conveyor 55 installed at the exit of the wood chip silo 54. Be transported.

  The wood chips that have reached the outlet of the wood chip silo 54 are transported by the second slat conveyor 55 to the wood chip inlet 201 at the top of the wood chep combustion boiler 10 and are fed into the combustion section at regular intervals.

The wood chips put into the combustion chamber are agitated and burned by the air ejected from the straight pipe type air supply pipes 17a to 17k and the cross type air supply pipes 18a to 18c.
That is, the air jetted in the horizontal direction from the straight pipe-type air supply pipes 17a to 17k disperses the wood chips that are input at regular intervals in the combustion section, and promotes the combustion of the wood chips.
Further, the air ejected from the horizontal branch pipes of the cruciform air supply pipes 18a to 18c suppresses the accumulation of wood chips on the bottom plate 14 and promotes the combustion of the wood chips.

  The air flowing through the straight pipe type air supply pipes 17a to 17k and the cruciform type air supply pipes 18a to 18c is increased in jetting speed by heat expansion due to the combustion heat of the wood chips, and the diffusion of the wood chips is further promoted. It becomes.

In addition, at the time of starting of the wood chip combustion boiler 10, it is necessary to ignite with a burner, but during normal operation, no auxiliary combustion with a burner or the like is necessary.
Furthermore, since the wood chip burns in the entire combustion part, it can be incinerated almost completely, and the ashing rate, which is usually about 8%, can be reduced to about 0.3%, which is 1/10 or less.

Since the exhaust gas generated in the combustion section 151 stays in the stay section 152 and is heated from below, the temperature reaches about 800 ° C., thereby preventing the generation of dioxins in the exhaust gas.
The exhaust gas staying in the staying part 152 enters the cyclone through the duct 19, and swirls to separate and remove dust, and is discharged from the exhaust gas discharge port 202.

  The exhaust gas discharged from the exhaust gas discharge port 202 is water-cooled in the exhaust gas cooler 56, passes through the bag filter 57, and is discharged by the exhaust gas treatment facility 58.

  The exhaust gas treatment facility 58 includes an exhaust fan, and sucks the exhaust gas in the wood chip combustion boiler 10 to make the pressure in the wood chip combustion boiler 10 negative and prevent the exhaust gas from leaking from the wood chip combustion boiler 10. doing.

  The exhaust gas discharged from the exhaust gas treatment facility 58 may be supplied to the wood chip silo 54 through the reflux path 59 and used as a heat source for drying the wood chips.

  Moreover, the hot water produced | generated by the water storage tank of the wood chip combustion boiler 10 can be used for hot water supply etc.

As described above, the wood chip combustion boiler according to the present invention can be incinerated to an ashing rate of about 0.3% without auxiliary combustion, and is industrially useful.
Moreover, the pruned branch combustion plant according to the present invention can be incinerated to an ashing rate of about 0.3% by crushing the pruned branches generated by pruning roadside trees into wood chips and burning them. Industrially useful.

DESCRIPTION OF SYMBOLS 10 ... Wood chep combustion boiler 11 ... Boiler 12 ... Cyclone 13 ... Outer wall 14 ... Bottom plate 15 ... Combustion chamber 16 ... Air chamber 17a-17k ... Straight pipe type air Supply pipes 18a to 18c: Cross air supply pipe 19 ... Duct 20 ... Top plate 51 ... Belt conveyor 52 ... Crusher 53 ... First slat conveyor 54 ... Silo 55 ... Second slat conveyor 56 ... Exhaust gas cooler 57 ... Bug filter 58 ... Exhaust gas treatment facility 59 ... Reflux passage for exhaust gas

Claims (5)

A furnace having a fuel inlet that is covered with a top plate that opens, a combustion part that burns wood chips introduced from the fuel inlet, and a retention part that temporarily retains exhaust gas generated in the combustion part;
A water tank that is installed on the outer periphery of the furnace and stores water heated by heat radiated from the furnace,
An air chamber installed at a lower portion of the furnace and supplying combustion air to the furnace;
A wood chip combustion boiler, comprising: a plurality of air supply pipes extending from the air chamber into the furnace and having surrounding air discharge holes for discharging air supplied from the air chamber. The air supply pipe is
A straight pipe-type air supply pipe extending straight upward from the air chamber;
A straight pipe portion extending upward into the furnace from the air chamber; and a branch pipe extending in both horizontal directions from the middle of the straight pipe portion; and the air chamber around the straight pipe portion and the branch pipe portion The wood chip combustion boiler according to claim 1, further comprising: a cruciform air supply pipe in which an air ejection hole for ejecting the air supplied from is formed.   The wood chip combustion boiler according to claim 2, wherein the number of the cruciform air supply pipes is smaller than that of the straight pipe air supply pipes. A crusher that crushes the pruned pruned branches into wood chips;
A chip silo for temporarily storing wood chips crushed by the crusher;
The wood chip combustion boiler according to any one of claims 1 to 3, wherein the wood chips stored in the chip silo are burned.
An exhaust gas cooler that water-cools the exhaust gas discharged from the staying part of the wood chip combustion boiler;
An exhaust gas treatment facility for exhausting the exhaust gas discharged from the exhaust gas cooler to the outside;
A pruned branch combustion plant having hot water generated in the water storage tank of the wood chip combustion boiler and hot water supply equipment for supplying hot water generated by exhaust gas in the gas cooler to the outside.   The pruned branch combustion plant according to claim 4, wherein the exhaust gas treatment facility includes a reflux path for returning the exhaust gas cooled by the exhaust gas cooler to the chip silo to dry the wood chips.

Images