JPWO2013088478A1 - Continuous combustion equipment for solid fuel containing incombustibles - Google Patents

Abstract

An economical combustion apparatus capable of continuous operation without generating clinker even with a solid fuel containing incombustibles. In this combustion apparatus, a screw conveyor 10 is installed in the center of the furnace body having a vertical cylindrical outer wall 1 for transferring solid fuel directly above. At the upper end of the casing cylinder 11 of the screw conveyor 10, a ring-shaped grate 15 that gradually descends and inclines toward the outside is fixed. The wing 14 is fixed. An outer wall 1 and a concentric inner wall 4 are provided above the screw conveyor 10 to supply combustion air swirled between the outer wall 1 and the inner wall 4 from above, and the combustion air is supplied to the solid fuel of the combustion section. In order to supply also from the inside, a large number of ejection holes 13 a, 14 a were provided in the upper end portion of the rotating shaft 13 and the stirring blade 14.

Description

  The present invention relates to a combustion apparatus capable of continuously incinerating solid fuel such as organic sludge and wood chips, for example.

  Conventionally, as a combustion device for solid fuel such as wood chips, an inner cylinder is provided in a cylindrical furnace body, solid fuel is continuously supplied from below the furnace body by a screw conveyor, and combustion air is moved down the outer periphery of the inner cylinder. There is a combustion device that is supplied as a swirling flow toward the vehicle and continuously burns at a high temperature (see, for example, Patent Document 1).

  In this combustion apparatus, solid fuel is continuously transferred by a continuous feeder (screw conveyor) onto a holding portion (grate) provided in a primary combustion chamber, and swirling combustion air from above and the continuous feeder Combustion air blown upward from the surroundings is supplied and burned, and the combustion gas rises in the center of the inner cylinder and leads to the secondary combustion chamber, where further swirling combustion air is supplied and burned at a high temperature. I am doing so.

JP2009-162414

The combustion furnace of Patent Literature 1 supplies swirling combustion air and burns the combustion gas burned in the primary combustion chamber at a higher temperature in the secondary combustion chamber, so that it can be completely burned and is solid. It is an incinerator that can incinerate fuel continuously.
However, solid fuel such as dried organic sludge generally contains a considerable amount of non-combustible material, and there is a considerable amount of non-flammable material that accumulates on the grate and on the combustion chamber wall along with the combustion gas. . And this often forms a clinker and combustion is inhibited.

In the combustion furnace of Patent Document 1, a maintenance opening is provided at the lower portion of the primary combustion chamber for manually taking out non-combustible materials and ash accumulated therein, but ash cannot be taken out during combustion. . For this reason, when combustion is inhibited by the generation of clinker, the supply of fuel and the supply of combustion air must be stopped to stop the combustion and wait for the furnace body to cool down.
Therefore, in this incinerator, it is necessary to select a solid fuel that does not contain incombustible materials, or incineration ash is light or fine particles and is discharged to the outside of the furnace with combustion. In addition, it is necessary to control the combustion so that the solid fuel is completely incinerated, and in some cases, stop the furnace to remove ash and clinker accumulated in the furnace body.

  Accordingly, an object of the present invention is to provide an economical combustion apparatus that does not generate a clinker even with a solid fuel containing an incombustible material and is capable of continuous operation.

  In order to achieve the above object, the solid fuel continuous combustion apparatus of the present invention employs the following means. In other words, a screw conveyor is installed in which a rotating shaft, on which spiral screw blades are fixed, is inserted into a casing cylinder in order to sequentially transfer solid fuel to the center of the furnace body having a vertical cylindrical outer wall. In the solid fuel continuous combustion apparatus provided with a cylindrical inner wall concentric with the outer wall above the screw conveyor, in order to supply the combustion air swirling spirally to the upper surface of the solid fuel, A screw-type grate that gradually descends and inclines outward toward the upper end of the casing cylinder of the screw conveyor is fixed apart from the outer wall, and the combustion air is also supplied from the inside of the solid fuel in the combustion section. It is characterized in that the rotating shaft of the conveyor is hollow and a hollow stirring blade is fixed to the upper end portion of the conveyor, and a plurality of ejection holes are provided in the upper end portion of the rotating shaft and the stirring blade.

The continuous combustion apparatus of the present invention transports solid fuel directly on an upright screw conveyor, supplies the combustion air to the upper end of the fuel by swirling it from above, and makes the rotating shaft of the screw conveyor hollow to have its upper end Are also ejected from a stirring blade and burned.
The solid fuel is burned at a time by the swirling combustion air from above and the combustion air ejected from the inside at the upper end of the screw conveyor, and is stirred by the stirring blades to promote combustion. Then, the solid fuel that is sequentially sent from the bottom slides down the burning thing along the slope, moves onto the grate at the upper end of the casing cylinder, and further burns completely while moving along the slope of the grate. ing. On the other hand, the combustion gas rises inside the inner wall, and the incinerated ash that does not float with the combustion gas falls from the peripheral edge of the grate to the lower ash reservoir.

In order for solid fuel containing incombustibles to be burned continuously without generating clinker, the solid fuel is always moved so as not to stagnate, and the combustible part of the solid fuel is completely burned and incinerated. It is necessary to remove ash from the burning part promptly.
In the present invention, the solid fuel is made to rise directly on the screw conveyor, its upper end portion is formed in a conical shape, a grate that gradually descends toward the outside is provided at the periphery thereof, and the inclination is inclined by the solid fuel that is sequentially transferred directly above. It is formed so that it always moves during combustion. Then, in order to completely burn the solid fuel, the combustion air is swirled from above and supplied to the combustion part, and is also supplied sufficiently from the inside of the solid fuel. Further, the solid fuel in the vicinity of the combustion part is agitated by a stirring blade. While supplying combustion air.

  Solid fuels are organic sludge such as sewage sludge, chicken dung and livestock dung, food processing sludge, etc., dried to a self-combustible water content, sludge in paper mills, mushroom medium, bamboo, wood, tires, synthetic resin It is a combustible material that excludes liquids such as oil and gaseous fuels such as natural gas, such as those made from chips. In addition, it may contain incombustible material. The shape is preferably granular, pellet, or chip.

The screw conveyor has a hollow rotating shaft with helical screw blades fixedly fitted in a casing cylinder. A hollow stirring blade is fixedly installed at the upper end of the rotating shaft, and the upper end of the casing cylinder is fixed. A ring-shaped grate that is gradually inclined downward toward the outside is fixed.
One screw blade may be used, but if the diameter of the screw blade is large, it may be multiple.
Further, when the diameter of the screw blade is large (500 mm or more), it is difficult to form the upper end portion of the solid fuel directly above in a conical shape. In such a case, the screw blade on the upper end side has a small diameter, and a guide member having a C-shaped cross section is provided on the outer peripheral portion thereof (Claim 4), so that the solid fuel in the central portion is sent faster than the peripheral portion. It is good to do so.

  It is desirable that the stirring blades have a hollow shape having a large number of ejection holes, have 2 to 6 blades, and are gradually lowered toward the outside (Claim 5), and have a shape with low rotational resistance.

The grate is provided on the outside of the casing cylinder so as to be gradually inclined downward. Although there are no particular limitations on the combustion air ejection holes of the grate, it is desirable that a large number of small holes of 1 to 3 mm be provided as described in claim 3.
In addition, the outer edge part of the grate is separated from the outer wall, and the incineration ash is dropped to the lower ash storage part. The area of the grate is determined in consideration of the size of the screw conveyor, the quality of the solid fuel, and the feed amount so that the solid fuel burns completely before falling into the ash reservoir.

Combustion air is swirled from above and fed from the inside of the solid fuel.
The combustion device is a negative pressure combustion system. In this means, it is convenient to provide a suction fan capable of adjusting the pressure on the exhaust side of the combustion gas.

  In order to properly feed the swirled combustion air supplied to the upper surface of the solid fuel into the solid fuel at the upper end of the screw conveyor, it is desirable to fix a ring-shaped guide that gradually descends from the outer wall below the inner wall. . In addition, as a means for supplying combustion air from the inside of the solid fuel, a cavity is provided in the circumference of the upper edge of the casing cylinder to supply combustion air to the grate, and an injection hole is provided in the upper end of the rotating shaft and the stirring blade. Although many are provided, it is desirable to provide a large number of ejection holes in the cylindrical portion of the rotating shaft and the cylindrical surface of the casing cylinder.

The use of this continuous combustion apparatus is not particularly limited, but when used as a boiler, a heat exchanger in which a water pipe is disposed along the inner wall of a cylindrical body concentric with the outer wall is provided directly above (Claim 6). Good.
Further, in order to completely burn the solid fuel, it is necessary to accurately grasp the property of the solid fuel and supply the combustion air amount corresponding to the supply amount. It is easy to obtain the amount of solid fuel from the number of revolutions per hour of the screw conveyor, but because it is a screw conveyor, the volume of the solid fuel changes due to being crushed or deformed during transfer. A thing with good accuracy cannot be obtained.
Therefore, as described in claim 7, a supply hopper for continuously supplying the solid fuel from the outside of the furnace is provided on the lower side surface of the screw conveyor so as to be inclined upward, and the solid hopper is spaced apart from the hopper. A first sensor and a second sensor for detecting the presence or absence may be provided to measure the supply amount of solid fuel per hour.

  In the solid fuel continuous combustion apparatus according to the present invention, a ring-shaped grate that gradually descends and inclines toward the outside is fixed to the upper end of the casing cylinder of the screw conveyor, apart from the outer wall, and combustion air is supplied to the solid fuel of the combustion section. Since the rotating shaft of the screw conveyor is hollow and a hollow stirring blade is fixed to the upper end portion of the screw conveyor, and a plurality of jet holes are provided in the upper end portion of the rotating shaft and the stirring blade. The solid fuel burns vigorously at the upper end portion of the screw conveyor, and the solid fuel sequentially sent from below moves to the sliding grate by the solid fuel. Since the solid fuel burns while moving, it can be quickly removed from the combustion section without generating clinker, so that continuous combustion is possible. Further, since no mechanical means for removing incinerated ash and incombustibles in the combustion section is required, the apparatus is simple and there is no fear of failure.

It is a front view which shows embodiment of the continuous combustion apparatus of the solid fuel of this invention. It is a cross-sectional perspective view which shows the detail of a screw conveyor part same as the above. It is a front sectional view showing another embodiment of the screw conveyor. It is a front view which shows embodiment of the top view of a stirring blade same as the above. It is a front view which shows embodiment at the time of setting it as a boiler. It is a perspective view which shows embodiment of the measurement means of solid fuel same as the above.

Hereinafter, an embodiment in which the continuous combustion apparatus of the present invention is used as a boiler will be described with reference to FIGS.
FIG. 1 is a front sectional view showing a combustion apparatus as an embodiment of the present invention.
In this combustion apparatus, a vertical cylindrical outer wall 1 forming a furnace body is fixed on a gantry 2, and a screw conveyor 10 is provided on a support base 2 a fixed to the gantry 2 at the lower center. .
A cylindrical inner wall 4 concentric with the outer wall 1 is provided above the screw conveyor 10, and a guide 5 fixed to the outer wall 1 is provided near the lower portion thereof. Here, the outer diameter of the middle wall 4 is approximately the same as the outer diameter of the screw conveyor 10.

The screw conveyor 10 includes a casing cylinder 11 and a rotating shaft 13 in which screw blades 12 are fixed in a spiral shape. The rotating shaft 13 is connected to driving means 3 that is transmitted from the outside through the central portion of the support base 2a. Yes.
This drive means 3 is connected to a drive shaft 3e from a motor 3a installed outside the gantry 2 via a sprocket 3b, a chain 3c, and a sprocket 3d, and the drive shaft 3e is connected to a rotating shaft 13 of the screw conveyor 10. Yes. The drive shaft 3e is hollow and has an air supply port 8b at the lower end. In the figure, 3f is a bearing.

A ring-shaped grate 15 is fixed on the upper end circumference of the casing cylinder 11 of the screw conveyor 10. The grate 15 is provided with a number of ejection holes 15b having a diameter of 1.5 mm, with the upper surface of the hollow outer ring material 15a inclined downward. The casing cylinder 11 to which the outer ring material 15a is fixed is also provided with a number of ejection holes 15c.
A hollow outer ring material 11a is also provided at a middle height of the casing cylinder 11, and a large number of ejection holes 11b are also provided in the casing cylinder 11 in that portion.

The rotating shaft 13 of the screw conveyor 10 is hollow, and a large number of ejection holes 13a are provided at the upper end thereof. In addition, a large number of ejection holes 13b are provided in a portion of the rotating shaft 13 where the screw blades 12 are not fixed.
Near the upper end of the rotating shaft 13, three stirring blades 14 are fixed horizontally. The stirring blade 14 is hollow and has a large number of ejection holes 14a on its upper surface.

In order to supply solid fuel, a fuel supply hopper 17 penetrating the outer wall 1 is fixed to the lower part of the side surface of the casing cylinder 11 of the screw conveyor 10. It is connected to.
Further, an ignition means 7 is provided on the outer wall 1 to ignite the propane gas (or liquid fuel) by blowing it onto the upper end of the solid fuel.
A gas inlet 21 through which combustion gas flows into the heat exchanger 20 immediately above is provided at the inner upper end of the middle wall 14.

  An air supply port 8 a directed in the tangential direction is provided at the upper end portion of the outer wall 1 so that the combustion air turns around the outer periphery of the inner wall 4. Further, an air supply port 8c communicating with the outer ring members 15a and 11a is also provided at a middle height position of the outer wall 1. The air supply ports 8a, 8b, and 8c are connected to a blower (not shown) by piping.

  The outer edge of the grate 15 at the upper end of the casing cylinder 11 is considerably spaced from the outer wall 1, and an ash storage section 6 whose periphery is closed is formed below the screw conveyor 10. Although not shown, the ash reservoir 6 is provided with an outlet for taking out the ash.

As shown in FIG. 5, a heat exchanger 20 is provided immediately above the continuous combustion apparatus.
In the heat exchanger 20, water pipes 22 are vertically and continuously arranged on the inner wall of the cylindrical body 20 a concentric with the outer wall 1 of the continuous combustion apparatus. The central portion of the lower end communicates with the continuous combustion apparatus, a gas inlet 21 through which combustion gas flows is provided, and a combustion gas pipe 23 connected to the ash recovery tower 25 is attached to the lower side of the furnace body 20a. ing.
The ash recovery tower 25 is an inverted conical cyclone 26 provided with an ash receiver 27 at the lower part, and an exhaust cylinder 28 is provided at the upper part.

Next, the operation of the continuous combustion apparatus configured as described above will be described.
First, while driving the belt conveyor which conveys solid fuel to the fuel supply hopper 17, the motor 3a of the drive means 3 is driven. Then, a blower (not shown) is driven to supply combustion air to the air supply ports 8a, 8b, 8c.
By driving the motor 3a, the rotary shaft 13 of the screw conveyor 10 rotates via the chain 3c and the drive shaft 3e.
As a result, the solid fuel stored in the fuel supply hopper 17 is transferred from the lower part of the screw conveyor 10 to the position immediately above by the screw blades 12.

  The solid fuel transferred by the screw conveyor 10 is sequentially transferred, so that the upper end portion thereof is formed in a substantially conical shape. When this state is reached, the ignition means 7 is activated to ignite the solid fuel. Note that this operation is only activated at the beginning of burning the solid fuel.

On the other hand, by the supply of combustion air, the outer periphery of the inner wall 4 is swung down from the air supply port 8a, guided by the inclined guide 5 and blown to the solid fuel at the upper end of the screw conveyor 10, and the air Combustion air is blown from the supply port 8b through the drive shaft 3e and the rotary shaft 13 through the jet hole 13a and the jet hole 14a of the stirring blade 14 from the lower side to the upper side of the solid fuel combustion section. Further, combustion air is ejected from the air supply port 8c through the ejection hole 15b of the grate 15 through the outer ring material 15a.
Further, combustion air is blown into the solid fuel in the screw conveyor 10. That is, the combustion air from the air supply port 8b is blown into the solid fuel from the jet hole 13b of the cylindrical portion of the rotating shaft 13, and the combustion air from the air supply port 8c is blown into the solid fuel through the outer ring member 11a. It is.
The air supply amounts to the air supply ports 8a, 8b, and 8c can be individually adjusted, and are adjusted according to the combustion state. In addition, the hollow of the rotary shaft 13 is separate from the passage to the ejection hole 13a of the upper end portion and the ejection hole 14a of the stirring blade 14 and the passage to the ejection hole 13b of the cylindrical portion, and the air supply amount can be adjusted individually. It is said.

The solid fuel at the upper end of the screw conveyor 10 burns vigorously at a high temperature of 800 degrees or more. Then, it rises by the solid fuel sequentially transferred from below, is stirred by the stirring blade 14, slides down along the inclination, and sequentially moves onto the grate 15. And it burns completely, moving along the inclination of the grate 15 while burning. It further moves and falls from the outer edge of the grate 15 to the ash reservoir 6.
Note that when the solid fuel falls into the ash reservoir 6, the combustible material is completely burned, and there is no unburned or burning fuel.

The combustion gas generated by the combustion blows up to the inside of the middle wall 4 and flows into the heat exchanger 20 from the upper gas inlet 21. Then, the water pipe 22 is heated to generate steam.
Most of the combustion gas containing incinerated ash is sent from the combustion gas pipe 23 to the ash recovery tower 25 outside the furnace. Combustion gas from the combustion gas pipe 23 is fed from the upper part of the cyclone 26 and moves downward while swirling along the wall. The ash is separated from the gas and collected in the ash receiver 27. The combustion gas from which the ash has been removed is discharged from the exhaust tube 28.
Although not shown, a suction fan capable of adjusting the pressure is provided behind the exhaust cylinder 28 so that the inside of the combustion apparatus has a negative pressure (minus 150 to 200 Pascals).

When the diameter of the screw blades 12 of the screw conveyor 10 is increased (500 mm or more), the upper end portion is not formed in a conical shape only with the sequentially fed solid fuel, and the inclination to the grate 15 may not be formed.
A means for forming the upper end portion of the solid fuel in a heap (conical shape) will now be described with reference to FIG. The same members as those in the above embodiment are denoted by the same reference numerals.

As shown in FIG. 3, the screw conveyor 10A is composed of a casing cylinder 11A and a rotating shaft 13A in which screw blades 12A and small-diameter blades 12B are fixed in a spiral shape. The stirring blades 14 are fixed horizontally.
Here, the small-diameter blade 12B has a diameter that is about half of the diameter of the screw blade 12A, and the length is about 1/4 of the upper side of the rotating shaft 13A.
A guide member 16 having a C-shaped cross section is provided so as to cover the outer periphery of the small-diameter blade 12B.

The guide member 16 is supported by the support member 16a from the casing cylinder 11A, is hollow, and has a large number of ejection holes 16b on the outer peripheral surface and the inner peripheral surface.
The guide member 16 communicates with the outer ring material 11c provided on the casing cylinder 11A, and the support member 16a is also hollow. The support member 16a is fixed at several places around the lower end of the guide member 16.
Since it is configured in this way, the solid fuel transferred to the upper end of the screw conveyor 10A is forcibly sent fast by the small-diameter blades 12B at the center and is guided by the shape of the guide member 16 and rises. , Formed in a conical shape.

  In the above-described embodiment, the stirring blades 14 fixed to the upper end portion of the rotating shaft 13 have three horizontal blades. However, when the diameter of the screw blades 12 increases, the amount of solid fuel to be stirred decreases. Therefore, it is necessary to eject more combustion air and to reduce the rotational resistance.

Another embodiment of the stirring blade 14 based on such a request will be described with reference to FIG.
The agitating blade 14A shown in FIG. 4A has a substantially branched antenna shape, and has a large number of ejection holes 14c on the upper surface. According to the stirring blade 14A, the solid fuel is stirred in a wide range and the combustion air is supplied from a wide range of the combustion portion.
Note that the branching shape may be appropriately determined depending on the diameter and rotation speed of the screw blades and the property of the solid fuel.

  A stirring blade 14B shown in FIG. 4 (b) is fixed to the rotary shaft 13 in the tangential direction as five substantially F-shapes, and has a number of ejection holes 14c on the upper surface. Therefore, the rotation resistance of the stirring blade 14B is small and it is effective even when the rotation speed of the rotating shaft 13 is high.

Although the screw blades 12 and 12A of the screw conveyors 10 and 10A in the above-described embodiment are described as one for the rotating shaft 13, it is natural to use one that has multiple threads or one that has a larger number of turns. May be. Moreover, it is good also considering only the lower end vicinity of the screw blades 12 and 12A as a multi-thread screw blade.
For example, when the screw blade 12 is spirally wound around the rotary shaft 13 using two blade materials, the supply port of the fuel supply hopper 17 to the screw conveyor 10 is engaged every 180 degrees of rotation. Therefore, the solid fuel is smoothly supplied, and the inclination according to the position of the screw blade 12 at the upper end of the screw conveyor 10 is smoothed. Therefore, the upper end is formed in a more conical shape.

The combustion air needs to be supplied in an appropriate amount according to the supply amount of the solid fuel.
By the way, the supply amount of the solid fuel can be increased or decreased by controlling the rotation speed of the screw conveyor. However, since the state of the solid fuel is considerably changed by the transfer of the screw conveyor, the actual supply amount is the same as that of the motor 3a of the drive means 3. It cannot be determined from the rotational speed.
A fuel supply device 30 that simply and accurately measures the amount of solid fuel supplied in the continuous combustion device will be described with reference to FIG.

This fuel supply device 30 is provided with a meter 31 having an opening / closing member 34 at the bottom above the fuel supply hopper 17, and a first sensor 32 that detects the presence of solid fuel and a first sensor on the upper side of the fuel supply hopper 17. Two sensors 33 are provided at intervals.
The first sensor 32 is turned on when it detects that there is no solid fuel, and the second sensor 33 is a space that is turned on when there is solid fuel and is partitioned by the first sensor 32 and the second sensor 33. Is set smaller than the capacity of the weighing instrument 31.

When measuring, the supply conveyor (not shown) which supplies solid fuel to the fuel supply hopper 17 is stopped in the state where the screw conveyor 10 is operating, and the measuring device 31 into which the solid fuel has been previously charged is stopped. Set at the upper end of the fuel supply hopper 17.
When the solid fuel in the fuel supply hopper 17 sequentially moves to the screw conveyor 10 and passes the second sensor 33 at the end, the solid fuel is turned OFF, and further, when the rear end passes through the first sensor 32, the first sensor 32 is passed. Sends an ON signal.
At the same time as the first sensor 32 is turned on, the opening / closing material 34 is operated to put the solid fuel in the meter 31 into the fuel supply hopper 17. At this time, since the end of the injected solid fuel is above the position of the second sensor 33, an ON signal is sent from the second sensor.

When the solid fuel is sequentially transferred to the screw conveyor 10 and the last of the solid fuel input from the meter 31 passes through the second sensor 33, the second sensor sends an OFF signal, and is further transferred to the first sensor 32. When the signal passes, the first sensor 32 sends an ON signal.
By measuring the time from when the solid fuel of the meter 31 is put into the fuel supply hopper 17 until the first sensor 32 sends an ON signal, the supply amount of solid fuel per hour to the screw conveyor 10 is measured. I can know.

DESCRIPTION OF SYMBOLS 1 Outer wall 2 Base 2a Support stand 3 Drive means 3a Motor 3b Sprocket 3c Chain 3d Sprocket 3e Drive shaft 3f Bearing 4 Middle wall 5 Guide 6 Ash storage part 7 Ignition means 8a Air supply port 8b Air supply port 8c Air supply port 10 Screw conveyor 10A Screw conveyor 11 Casing cylinder 11A Casing cylinder 11a Outer ring material 11b Outlet hole 11c Outer ring material 12 Screw blade 12A Screw blade 12B Screw blade 12a Small diameter blade 13 Rotating shaft 13A Rotating shaft 13a Ejection hole 13b Ejection hole 14 Stirring blade 14A Stirring blade 14B Stirring blade 14a Ejection hole 14c Ejection hole 15 Grate 15a Outer ring material 15b Ejection hole 15c Ejection hole 16 Guide member 16a Support member 16b Ejection hole 17 Fuel supply hopper 20 Heat exchanger 20a Tubular body 21 Gas inlet 22 Water pipe 23 Combustion Gas pipe 5 ash recovery column 26 cyclone 27 ash receiver 28 exhaust tower 30 metering device 31 measuring cup 32 first sensor 33 second sensor 34 chute

The present invention relates to a combustion apparatus capable of continuously incinerating solid fuel containing incombustible materials such as dried sewage sludge .

  Conventionally, as a combustion device for solid fuel such as wood chips, an inner cylinder is provided in a cylindrical furnace body, solid fuel is continuously supplied from below the furnace body by a screw conveyor, and combustion air is moved down the outer periphery of the inner cylinder. There is a combustion device that is supplied as a swirling flow toward the vehicle and continuously burns at a high temperature (see, for example, Patent Document 1).

  In this combustion apparatus, solid fuel is continuously transferred by a continuous feeder (screw conveyor) onto a holding portion (grate) provided in a primary combustion chamber, and swirling combustion air from above and the continuous feeder Combustion air blown upward from the surroundings is supplied and burned, and the combustion gas rises in the center of the inner cylinder and leads to the secondary combustion chamber, where further swirling combustion air is supplied and burned at a high temperature. I am doing so.

JP2009-162414

The combustion furnace of Patent Literature 1 supplies swirling combustion air and burns the combustion gas burned in the primary combustion chamber at a higher temperature in the secondary combustion chamber, so that it can be completely burned and is solid. It is an economical incinerator that can incinerate fuel continuously.
However, solid fuel such as dried organic sludge generally contains a considerable amount of non-combustible material, and there is a considerable amount of non-flammable material that accumulates on the grate and on the combustion chamber wall along with the combustion gas. . And this often forms a clinker and combustion is inhibited.

In the combustion furnace of Patent Document 1, a maintenance opening is provided at the lower portion of the primary combustion chamber for manually taking out non-combustible materials and ash accumulated therein, but ash cannot be taken out during combustion. . For this reason, when combustion is inhibited by the generation of clinker, the supply of fuel and the supply of combustion air must be stopped to stop the combustion and wait for the furnace body to cool down.
Therefore, in this incinerator, it is necessary to incinerate completely using solid fuel that does not contain incombustible materials, and to periodically stop the furnace to remove ash and clinker accumulated in the furnace body. The

  Accordingly, an object of the present invention is to provide an economical combustion apparatus that does not generate a clinker even with a solid fuel containing an incombustible material and is capable of continuous operation.

In order to achieve the above object, the solid fuel continuous combustion apparatus of the present invention employs the following means. In other words, a screw conveyor is installed in which a rotating shaft with helical screw blades fixedly inserted in a casing cylinder is placed in the center of the furnace body having a vertical cylindrical outer wall in order to sequentially transfer solid fuel. In order to supply the combustion air swirling spirally to the upper surface of the solid fuel, continuous combustion of the solid fuel including incombustible material provided with a cylindrical inner wall concentric with the outer wall above the screw conveyor In the apparatus, a hollow outer ring member is provided around the upper end circumference of the casing cylinder of the screw conveyor at a distance from the outer wall, and the upper surface of the outer ring member is inclined downward to inject the combustion air of 1 to 3 mm. A grate with a large number of holes is formed to supply combustion air to the outer ring material and also supply combustion air from the inside of the solid fuel. State disturbance Stirring blades are fixed, a large number of jet holes are provided in the upper end portion of the rotating shaft and the stirring blades, the solid fuel at the upper end portion transferred by the screw conveyor is burned, and the solid fuel sequentially transferred from below It moves on the grate along the slope while rising and burning, and falls from the outer edge of the grate to the ash reservoir .

In the continuous combustion apparatus of the present invention, the solid fuel is transferred directly above by a standing screw conveyor so that its upper end is formed in a conical shape, and the combustion air is swirled from above to be supplied to the upper surface of the solid fuel. It is also ejected from the inside of the fuel and burned. Then, the solid fuel in the lower part of the combustion part is stirred and moved by the stirring blade provided at the upper end of the rotating shaft of the screw conveyor, and the combustion is promoted. It is lowered along, moved onto the grate at the upper end of the casing cylinder, and further burned completely while moving along the inclination of the grate. On the other hand, the combustion gas rises to the inside of the inner wall, and the incinerated ash and incombustibles that do not float with the combustion gas fall from the peripheral edge of the grate to the lower ash reservoir.

In order for solid fuel containing incombustibles to be burned continuously without generating clinker, the solid fuel is always moved so as not to stagnate, and the combustible part of the solid fuel is completely burned and incinerated. It is necessary to remove ash from the burning part promptly.
In the present invention, the solid fuel is made to rise directly on the screw conveyor, its upper end portion is formed in a conical shape, a grate that gradually descends toward the outside is provided at the periphery thereof, and the inclination is inclined by the solid fuel that is sequentially transferred directly above. It is formed so that it always moves during combustion. Then, in order to completely burn the solid fuel, the combustion air is swirled from above and supplied to the combustion part, and is also supplied sufficiently from the inside of the solid fuel. Further, the solid fuel in the vicinity of the combustion part is agitated by a stirring blade. While supplying combustion air.

Solid fuel, which dried sewage sludge, manure and animal manure, the organic sludge, such as food processing sludge self combustible moisture content, good sludge, mushrooms medium such as in paper mills, shape, granular, pellets A chip shape is desirable.

The screw conveyor has a hollow rotating shaft with helical screw blades fixedly fitted in a casing cylinder. A hollow stirring blade is fixedly installed at the upper end of the rotating shaft, and the upper end of the casing cylinder is fixed. A ring-shaped grate that is gradually inclined downward toward the outside is fixed.
One screw blade may be used, but if the diameter of the screw blade is large, it may be multiple.
Further, when the diameter of the screw blade is large (500 mm or more), it is difficult to form the upper end portion of the solid fuel directly above in a conical shape. In such a case, the screw blade on the upper end side has a small diameter, and a guide member having a cross-sectional shape is provided on the outer periphery thereof (Claim 3 ), so that the solid fuel at the center is sent faster than the periphery. It is good to do so.

It is desirable that the stirring blades have a hollow shape having a large number of ejection holes, have 2 to 6 blades, and are gradually lowered toward the outside (claim 4 ), and have a shape with low rotational resistance.

The grate is provided on the outside of the casing cylinder so as to be gradually inclined downward. Ejection holes of the combustion air of the grate shall be provided a large number of small holes of 1 to 3 mm.
In addition, the outer edge part of the grate is separated from the outer wall, and the incineration ash is selected so as to fall into the lower ash storage part. The area of the grate is determined in consideration of the size of the screw conveyor, the quality of the solid fuel, and the feed amount so that the solid fuel burns completely before falling into the ash reservoir.

  Combustion air is swirled from above and fed from the inside of the solid fuel. The combustion device is a negative pressure combustion system. In this means, it is convenient to provide a suction fan capable of adjusting the pressure on the exhaust side of the combustion gas.

  In order to properly feed the swirled combustion air supplied to the upper surface of the solid fuel into the solid fuel at the upper end of the screw conveyor, it is desirable to fix a ring-shaped guide that gradually descends from the outer wall below the inner wall. . In addition, as a means for supplying combustion air from the inside of the solid fuel, a cavity is provided in the circumference of the upper edge of the casing cylinder to supply combustion air to the grate, and an injection hole is provided in the upper end of the rotating shaft and the stirring blade. Although many are provided, it is desirable to provide a large number of ejection holes in the cylindrical portion of the rotating shaft and the cylindrical surface of the casing cylinder.

The use of this continuous combustion apparatus is not particularly limited, but when used as a boiler, a heat exchanger in which a water pipe is disposed along the inner wall of a cylindrical body concentric with the outer wall is provided directly above (Claim 5 ). Good. Further, in order to completely burn the solid fuel, it is necessary to accurately grasp the property of the solid fuel and supply the combustion air amount corresponding to the supply amount. It is easy to obtain the solid fuel feed rate from the number of revolutions per hour of the screw conveyor, but because it is a screw conveyor, it is crushed or deformed during transfer, and its volume changes, so it has high accuracy. Cannot be obtained.
Therefore, as described in claim 6 , a supply hopper for continuously supplying the solid fuel from the outside of the furnace is provided on the lower side surface of the screw conveyor so as to be inclined upward, and the solid hopper is spaced apart from the hopper. A first sensor and a second sensor for detecting the presence or absence may be provided to measure the supply amount of solid fuel per hour.

In the continuous combustion apparatus for solid fuel containing incombustible material according to the present invention , a hollow outer ring material is provided on the circumference of the upper end of the casing cylinder of the screw conveyor at a distance from the outer wall, and the upper surface of the outer ring material is outside. In order to supply the combustion air to the outer ring material and also supply the combustion air from the inside of the solid fuel, the screw is formed. Since the rotating shaft of the conveyor is hollow and a hollow stirring blade is fixed at the upper end of the rotating shaft, and a large number of jet holes are provided in the upper end of the rotating shaft and the stirring blade, the solid fuel transferred by the screw conveyor is It is formed in a conical shape and burns from its upper surface, and the solid fuel sequentially sent from below moves the slope to the sliding grate, completely burns while moving and falls from the periphery. Since the solid fuel burns while moving, it can be quickly removed from the combustion section without generating clinker, so that continuous combustion is possible. Further, since no mechanical means for removing incinerated ash and incombustibles in the combustion section is required, the apparatus is simple and there is no fear of failure.

It is a front view which shows embodiment of the continuous combustion apparatus of the solid fuel of this invention. It is a cross-sectional perspective view which shows the detail of a screw conveyor part same as the above. It is a front sectional view showing another embodiment of the screw conveyor. It is a front view which shows embodiment of the top view of a stirring blade same as the above. It is a front view which shows embodiment at the time of setting it as a boiler. It is a perspective view which shows embodiment of the measurement means of solid fuel same as the above.

Hereinafter, an embodiment in which the continuous combustion apparatus of the present invention is used as a boiler will be described with reference to FIGS.
FIG. 1 is a front sectional view showing a combustion apparatus as an embodiment of the present invention.
In this combustion apparatus, a vertical cylindrical outer wall 1 forming a furnace body is fixed on a gantry 2, and a screw conveyor 10 is provided on a support base 2 a fixed to the gantry 2 at the lower center. .
A cylindrical inner wall 4 concentric with the outer wall 1 is provided above the screw conveyor 10, and a guide 5 fixed to the outer wall 1 is provided near the lower portion thereof. Here, the outer diameter of the middle wall 4 is approximately the same as the outer diameter of the screw conveyor 10.

The screw conveyor 10 includes a casing cylinder 11 and a rotating shaft 13 in which screw blades 12 are fixed in a spiral shape. The rotating shaft 13 is connected to driving means 3 that is transmitted from the outside through the central portion of the support base 2a. Yes.
This drive means 3 is connected to a drive shaft 3e from a motor 3a installed outside the gantry 2 via a sprocket 3b, a chain 3c, and a sprocket 3d, and the drive shaft 3e is connected to a rotating shaft 13 of the screw conveyor 10. Yes. The drive shaft 3e is hollow and has an air supply port 8b at the lower end. In the figure, 3f is a bearing.

A ring-shaped grate 15 is fixed on the upper end circumference of the casing cylinder 11 of the screw conveyor 10. The grate 15 is provided with a number of ejection holes 15b having a diameter of 1.5 mm, with the upper surface of the hollow outer ring material 15a inclined downward. The casing cylinder 11 to which the outer ring material 15a is fixed is also provided with a number of ejection holes 15c.
A hollow outer ring material 11a is also provided at a middle height of the casing cylinder 11, and a large number of ejection holes 11b are also provided in the casing cylinder 11 in that portion.

The rotating shaft 13 of the screw conveyor 10 is hollow, and a large number of ejection holes 13a are provided at the upper end thereof. In addition, a large number of ejection holes 13b are provided in a portion of the rotating shaft 13 where the screw blades 12 are not fixed.
Near the upper end of the rotating shaft 13, three stirring blades 14 are fixed horizontally. The stirring blade 14 is hollow and has a large number of ejection holes 14a on its upper surface.

In order to supply solid fuel, a fuel supply hopper 17 penetrating the outer wall 1 is fixed to the lower part of the side surface of the casing cylinder 11 of the screw conveyor 10. It is connected to.
Further, an ignition means 7 is provided on the outer wall 1 to ignite the propane gas (or liquid fuel) by blowing it onto the upper end of the solid fuel.
A gas inlet 21 through which combustion gas flows into the heat exchanger 20 immediately above is provided at the inner upper end of the middle wall 14.

  An air supply port 8 a directed in the tangential direction is provided at the upper end portion of the outer wall 1 so that the combustion air turns around the outer periphery of the inner wall 4. Further, an air supply port 8c communicating with the outer ring members 15a and 11a is also provided at a middle height position of the outer wall 1. The air supply ports 8a, 8b, and 8c are connected to a blower (not shown) by piping.

  The outer edge of the grate 15 at the upper end of the casing cylinder 11 is considerably spaced from the outer wall 1, and an ash storage section 6 whose periphery is closed is formed below the screw conveyor 10. Although not shown, the ash reservoir 6 is provided with an outlet for taking out the ash.

As shown in FIG. 5, a heat exchanger 20 is provided immediately above the continuous combustion apparatus.
In the heat exchanger 20, a water tube 22 is spirally arranged on the inner wall of the cylindrical body 20 a concentric with the outer wall 1 of the continuous combustion apparatus. The central portion of the lower end communicates with the continuous combustion apparatus, a gas inlet 21 through which combustion gas flows is provided, and a combustion gas pipe 23 connected to the ash recovery tower 25 is attached to the lower side of the furnace body 20a. ing.
The ash recovery tower 25 is an inverted conical cyclone 26 provided with an ash receiver 27 at the lower part, and an exhaust cylinder 28 is provided at the upper part.

Next, the operation of the continuous combustion apparatus configured as described above will be described.
First, while driving the belt conveyor which conveys solid fuel to the fuel supply hopper 17, the motor 3a of the drive means 3 is driven. Then, a blower (not shown) is driven to supply combustion air to the air supply ports 8a, 8b, 8c.
By driving the motor 3a, the rotary shaft 13 of the screw conveyor 10 rotates via the chain 3c and the drive shaft 3e.
As a result, the solid fuel stored in the fuel supply hopper 17 is transferred from the lower part of the screw conveyor 10 to the position immediately above by the screw blades 12.

  The solid fuel transferred by the screw conveyor 10 is sequentially transferred, so that the upper end portion thereof is formed in a substantially conical shape. When this state is reached, the ignition means 7 is activated to ignite the solid fuel. Note that this operation is only activated at the beginning of burning the solid fuel.

On the other hand, by the supply of combustion air, the outer periphery of the inner wall 4 is swung down from the air supply port 8a, guided by the inclined guide 5 and blown to the solid fuel at the upper end of the screw conveyor 10, and the air Combustion air is blown from the supply port 8b through the drive shaft 3e and the rotary shaft 13 through the jet hole 13a and the jet hole 14a of the stirring blade 14 from the lower side to the upper side of the solid fuel combustion section. Further, combustion air is ejected from the air supply port 8c through the ejection hole 15b of the grate 15 through the outer ring material 15a.
Further, combustion air is blown into the solid fuel in the screw conveyor 10. That is, the combustion air from the air supply port 8b is blown into the solid fuel from the jet hole 13b of the cylindrical portion of the rotating shaft 13, and the combustion air from the air supply port 8c is blown into the solid fuel through the outer ring member 11a. It is.

The solid fuel at the upper end of the screw conveyor 10 is burned at a high temperature of 800 ° C. or more, and is slid down along the slope and moved onto the grate 15 by the solid fuel and the stirring blade 14 sequentially transferred from below. Furthermore, it moves to the outer edge along the inclination of the grate 15 and falls to the ash storage section 6.
Note that when the solid fuel falls into the ash reservoir 6, the combustible material is completely burned, and there is no unburned or burning fuel.

The combustion gas generated by the combustion blows up to the inside of the middle wall 4 and flows into the heat exchanger 20 from the upper gas inlet 21. Then, the water pipe 22 is heated to generate steam.
Most of the combustion gas containing incinerated ash is sent from the combustion gas pipe 23 to the ash recovery tower 25 outside the furnace. Combustion gas from the combustion gas pipe 23 is fed from the upper part of the cyclone 26 and moves downward while swirling along the wall. The ash is separated from the gas and collected in the ash receiver 27. The combustion gas from which the ash has been removed is discharged from the exhaust tube 28.
Although not shown, a suction fan capable of adjusting the pressure is provided behind the exhaust cylinder 28 so that the inside of the combustion apparatus has a negative pressure (minus 150 to 200 Pascals).

When the diameter of the screw blades 12 of the screw conveyor 10 is increased (500 mm or more), the upper end portion is not formed in a conical shape only with the solid fuel that is sequentially fed.
A means for forming the upper end portion of the solid fuel in a conical shape will now be described with reference to FIG. The same members as those in the above embodiment are denoted by the same reference numerals.

As shown in FIG. 3, the screw conveyor 10A is composed of a casing cylinder 11A and a rotating shaft 13A in which screw blades 12A and small-diameter blades 12B are fixed in a spiral shape. The stirring blades 14 are fixed horizontally.
Here, the small-diameter blade 12B has a diameter that is about half of the diameter of the screw blade 12A, and the length is about 1/4 of the upper side of the rotating shaft 13A.
A guide member 16 having a C-shaped cross section is provided so as to cover the outer periphery of the small-diameter blade 12B.

The guide member 16 is supported by the support member 16a from the casing cylinder 11A, is hollow, and has a large number of ejection holes 16b on the outer peripheral surface and the inner peripheral surface.
The guide member 16 communicates with the outer ring material 11c provided on the casing cylinder 11A, and the support member 16a is also hollow. The support member 16a is fixed at several places around the lower end of the guide member 16.
Since it is configured in this way, the solid fuel transferred to the upper end of the screw conveyor 10A is forcibly sent fast by the small-diameter blades 12B at the center and is guided by the shape of the guide member 16 and rises. , Formed in a conical shape.

  In the above-described embodiment, the stirring blades 14 fixed to the upper end portion of the rotating shaft 13 have three horizontal blades. However, when the diameter of the screw blades 12 increases, the amount of solid fuel to be stirred decreases. Therefore, it is necessary to eject more combustion air and to reduce the rotational resistance.

Another embodiment of the stirring blade 14 based on such a request will be described with reference to FIG. The agitating blade 14A shown in FIG. 4A has a substantially branched antenna shape, and has a large number of ejection holes 14c on the upper surface. According to the stirring blade 14A, the solid fuel is stirred in a wide range and the combustion air is supplied from a wide range of the combustion portion.
Note that the branching shape may be appropriately determined depending on the diameter and rotation speed of the screw blades and the property of the solid fuel.

  A stirring blade 14B shown in FIG. 4 (b) is fixed to the rotary shaft 13 in the tangential direction as five substantially F-shapes, and has a number of ejection holes 14c on the upper surface. Therefore, the rotation resistance of the stirring blade 14B is small and it is effective even when the rotation speed of the rotating shaft 13 is high.

Although the screw blades 12 and 12A of the screw conveyors 10 and 10A in the above-described embodiment are described as one for the rotating shaft 13, it is natural to use one that has multiple threads or one that has a larger number of turns. May be. Moreover, it is good also considering only the lower end vicinity of the screw blades 12 and 12A as a multi-thread screw blade.
For example, when the screw blade 12 is spirally wound around the rotary shaft 13 using two blade materials, the supply port of the fuel supply hopper 17 to the screw conveyor 10 is engaged every 180 degrees of rotation. Therefore, the solid fuel is smoothly supplied, and the inclination according to the position of the screw blade 12 at the upper end of the screw conveyor 10 is smoothed. Therefore, the upper end is formed in a more conical shape.

The combustion air needs to be supplied in an appropriate amount according to the supply amount of the solid fuel.
By the way, the supply amount of the solid fuel can be increased or decreased by controlling the rotation speed of the screw conveyor. However, since the state of the solid fuel is considerably changed by the transfer of the screw conveyor, the actual supply amount is the same as that of the motor 3a of the drive means 3. It cannot be determined from the rotational speed.
A fuel supply device 30 that simply and accurately measures the amount of solid fuel supplied in the continuous combustion device will be described with reference to FIG.

This fuel supply device 30 is provided with a meter 31 having an opening / closing member 34 at the bottom above the fuel supply hopper 17, and a first sensor 32 that detects the presence of solid fuel and a first sensor on the upper side of the fuel supply hopper 17. Two sensors 33 are provided at intervals.
The first sensor 32 is turned on when it detects that there is no solid fuel, and the second sensor 33 is a space that is turned on when there is solid fuel and is partitioned by the first sensor 32 and the second sensor 33. Is set smaller than the capacity of the weighing instrument 31.

When measuring, the supply conveyor (not shown) which supplies solid fuel to the fuel supply hopper 17 is stopped in the state where the screw conveyor 10 is operating, and the measuring device 31 into which the solid fuel has been previously charged is stopped. Set at the upper end of the fuel supply hopper 17.
When the solid fuel in the fuel supply hopper 17 sequentially moves to the screw conveyor 10 and passes the second sensor 33 at the end, the solid fuel is turned OFF, and further, when the rear end passes through the first sensor 32, the first sensor 32 is passed. Sends an ON signal.
At the same time as the first sensor 32 is turned on, the opening / closing material 34 is operated to put the solid fuel in the meter 31 into the fuel supply hopper 17. At this time, since the end of the injected solid fuel is above the position of the second sensor 33, an ON signal is sent from the second sensor.

When the solid fuel is sequentially transferred to the screw conveyor 10 and the last of the solid fuel input from the meter 31 passes through the second sensor 33, the second sensor sends an OFF signal, and is further transferred to the first sensor 32. When the signal passes, the first sensor 32 sends an ON signal.
By measuring the time from when the solid fuel of the meter 31 is put into the fuel supply hopper 17 until the first sensor 32 sends an ON signal, the supply amount of solid fuel per hour to the screw conveyor 10 is measured. I can know.

DESCRIPTION OF SYMBOLS 1 Outer wall 2 Base 2a Support stand 3 Drive means 3a Motor 3b Sprocket 3c Chain 3d Sprocket 3e Drive shaft 3f Bearing 4 Middle wall 5 Guide 6 Ash storage part 7 Ignition means 8a Air supply port 8b Air supply port 8c Air supply port 10 Screw conveyor 10A Screw conveyor 11 Casing cylinder 11A Casing cylinder 11a Outer ring material 11b Outlet hole 11c Outer ring material 12 Screw blade 12A Screw blade 12B Screw blade 12a Small diameter blade 13 Rotating shaft 13A Rotating shaft 13a Ejection hole 13b Ejection hole 14 Stirring blade 14A Stirring blade 14B Stirring blade 14a Ejection hole 14c Ejection hole 15 Grate 15a Outer ring material 15b Ejection hole 15c Ejection hole 16 Guide member 16a Support member 16b Ejection hole 17 Fuel supply hopper 20 Heat exchanger 20a Tubular body 21 Gas inlet 22 Water pipe 23 Combustion Gas pipe 5 ash recovery column 26 cyclone 27 ash receiver 28 exhaust tower 30 metering device 31 measuring cup 32 first sensor 33 second sensor 34 chute

Claims (7)

  A screw conveyor is installed in the center of the furnace body with a vertical cylindrical outer wall. In the solid fuel continuous combustion apparatus in which a cylindrical inner wall concentric with the outer wall is provided above the screw conveyor in order to supply spirally swirling combustion air to the upper surface of the solid fuel, the screw conveyor A ring-shaped grate that gradually descends and inclines toward the outside at the upper end of the casing cylinder is fixed apart from the outer wall, and combustion air is also supplied from the inside of the solid fuel in the combustion section. A solid fuel continuous combustion apparatus characterized in that a rotating shaft is hollow and a hollow stirring blade is fixed at an upper end of the rotating shaft, and a plurality of injection holes are provided in the upper end of the rotating shaft and the stirring blade.   In order to guide the combustion air swirling spirally to the upper surface of the solid fuel, a ring-shaped guide gradually descending from the outer wall is fixed below the inner wall, and the cylindrical portion of the rotating shaft of the screw conveyor and the casing 2. The solid fuel continuous combustion apparatus according to claim 1, wherein a plurality of ejection holes are provided in a cylindrical surface of the cylinder, and combustion air is also supplied to the solid fuel in the screw conveyor that is transferred directly above. .   2. The solid fuel continuous combustion apparatus according to claim 1, wherein the grate is provided with many small holes of 1 to 3 mm as ejection holes for combustion air.   The screw conveyor is characterized in that the upper end portion of the solid fuel to be transported immediately above is formed in a conical shape, so that the screw blade on the upper end side has a small diameter, and a guide member having a cross-sectional shape in the outer periphery is provided. The continuous combustion apparatus for solid fuel according to any one of claims 1 to 3.   The continuous stirring of the solid fuel according to any one of claims 1 to 4, wherein the stirring blades fixed to the rotating shaft of the screw conveyor are gradually lowered toward the outside as 2 to 6 stirring blades. Combustion device.   6. The continuous combustion of solid fuel according to claim 1, wherein a heat exchanger having a water pipe disposed along an inner wall of a cylindrical body concentric with the outer wall is provided immediately above. apparatus.   In the lower side of the screw conveyor, a supply hopper for continuously supplying solid fuel from the outside of the furnace is inclined upward, and in order to measure the supply amount of solid fuel per hour to the hopper, the presence or absence of solid fuel The solid fuel continuous combustion apparatus according to claim 6, wherein a first sensor and a second sensor for detecting fuel are provided at intervals in the hopper.

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