JP4206440B2 - Solid biomass fuel combustion system - Google Patents

Description

The present invention relates to a combustion apparatus for efficiently burning molded granular or pellet-shaped solid biomass fuel made from wood, straw, and other agricultural by-products, and using it as a stove, boiler, dryer, gasification furnace, etc. Is.

Background technology

Even if pellets are burned with a wood-burning stove or sawdust stove that is currently on the market, the amount of ash after combustion is large because the pellets are stacked and compressed at a density about 3 times that of ordinary wood, and the surface pellets As a result, the ash of ash does not burn to the inside to limit the combustion air to the pellets below it, and it becomes a state that smoldering and smoldering continues, and it is a fact that it is difficult to obtain the amount of heat due to combustion, actually Moreover, pellets are not used in wood-burning stoves and sawdust stoves that are currently on the market. Therefore, it is considered that a combustion apparatus specific to pellets has been developed.

Currently, there are two types of combustion devices for burning pellets: pellet stoves and pellet burners.
Pellet stoves are imported from many foreign products in North America and Scandinavia, but the products made in Japan are the two pellets from Sunpot Co., Ltd., Kawagoe City, Saitama Prefecture, and Yamamoto Manufacturing Co., Ltd., Tendo City, Yamagata Prefecture. There is a stove.
Pellet burners are imported from Italy but are sold in Japan. There are pellet burners from Tachikawa City Olympia Industry Co., Ltd. and Toyota City Nikko Engineering Co., Ltd., Shizuoka Prefecture. in use.

The combustion device of the pellet stove has a small combustion cup at the lower center of the large combustion chamber, and fuel is supplied into the cup little by little from the upper side by a screw feeder, and there are holes on the side and lower surface of the combustion cup. It is a device in which combustion air from the blower is blown into the cup through the hole and burns, and the ash of the pellets burning red heat is scattered by the combustion air from the blower above the combustion chamber. The fallen ash is accumulated in the ash tray located below by the combustion cup.

A typical example of a combustion apparatus for a pellet burner is that a combustion chamber is set sideways and a combustion cylinder is slightly smaller in the combustion chamber, and fuel is gradually fed into the combustion cylinder little by little from above with a screw feeder. The supplied combustion air from the blower is blown into the combustion chamber and enters the combustion cylinder through the holes on the side, bottom, and diagonally upper sides of the combustion cylinder, burns the pellets sideways, and burns while scattering ash. The structure is such that ash is accumulated in the boiler ash tray.

As described above, all the current pellet stoves and pellet burners have the same minimum requirements for burning the pellets.
First, it is necessary to supply the fuel little by little so that the fuel does not accumulate thickly. The second point is that the combustion air needs to be heated and supplied with a sufficient amount of oxygen and air with a wind pressure that scatters ash.
These two minimum requirements are that the drive of the motor using electricity functions as a screw feeder and a blower.

In addition, pellet stoves and pellet burners that do not use electricity at present, that is, that do not use a motor, have not been seen in the market or literature, so they cannot be described.

The conventional combustion apparatus has the disadvantage that pellet combustion is not possible when there is no electricity or when the motor fails.
That is, the recycling of solar energy is governed by the presence or absence of electrical energy or the quality of electrical equipment.

Also, if you want to obtain clean combustion exhaust gas and high-efficiency thermal energy, the combustion gas generated from the primary combustion should stay in the secondary combustion chamber for about 2 seconds to achieve sufficient secondary combustion. Because of forced combustion by the blower, there is no distinction between primary combustion and secondary combustion, and sufficient secondary combustion is not secured

In addition, in pellet burners that require strong thermal power, naturally the pressure and amount of air from the blower increases, so when using a cyclone dust collector in combination with or without using a cyclone dust collector to prevent generated sparks and scattered ash, A great labor is required for cleaning the scattered ash adhering to the heat exchange pipe in the boiler, and there is an inconvenience that extra equipment and a great labor are required as compared with kerosene and heavy oil boilers.

The present invention aims to solve these inconveniences, in order to ensure that secondary combustion is ensured, ash scattering is ensured, and pellet combustion is continued efficiently without using electrical energy. , It is possible to smoothly supply hot heated fuel into a combustion chamber that can be kept hot at 800 ° C. or higher, supply a sufficient amount of hot air heated, and continue to fly ash on the surface of pellets during combustion. As a result of repeated experiments to clear these requirements, the present invention could be completed.

In addition, if electric devices such as a screw feeder and a blower are used in the present invention, the apparatus can be downsized and the amount of generated heat can be greatly increased.

Among the present inventions, the invention according to claim 1 is such that the fuel flows from the top to the bottom due to the natural descent, and the combustion air is joined downward from the secondary combustion chamber, and the draft of the chimney or heat exchange device. In a combustion apparatus that performs downward combustion, an opening is provided in the center of the bottom of the primary combustion chamber that continues below the fuel tube, and the soot is turned upside down to cover the opening and provide a space above the opening. A bowl-shaped three-dimensional rooster is placed, and a mortar-shaped slope hearth is formed around the opening so that the pellet fuel burns three-dimensionally. Combustion air holes are formed in the slope hearth and the primary combustion chamber wall. The flame, combustion gas, and ash burned by providing the necessary and sufficient number pass through the vertical solid rooster, enter the secondary combustion chamber through the opening, and the combustion gas undergoes secondary combustion, ash Is in the combustion device characterized by descending to the ash reservoir.

According to a second aspect of the present invention, an eave is provided on the hole so that pellet fuel does not enter into the combustion air hole provided in the slope hearth and the wall of the primary combustion chamber. Thus, the sloped hearth forms an inclined stepped hearth, and the direction of the combustion air holes is also aligned with the direction of the inclined stepped shape so that the combustion air is efficiently supplied to the fuel. To do.

According to a third aspect of the present invention, the combustion air holes provided in the slope hearth and the primary combustion chamber wall are configured to promote ash scattering by arranging the number of holes and the size of the holes. The amount and ratio of primary combustion air and secondary combustion air are set, and sufficient secondary combustion is achieved in the secondary combustion chamber.

The invention described in claim 4 is characterized in that a fireproof heat insulating material is used for the slope hearth and the wall of the primary combustion chamber to prevent metal oxidation and high-temperature combustion of the fuel.

According to a fifth aspect of the present invention, there is provided combustion air that surrounds and joins the fuel cylinder and the primary combustion chamber, communicates with the combustion air holes, and supplies combustion air to any of the combustion air holes at a constant pressure. A supply chamber is provided.

Further, the invention according to claim 6 is the boundary between the fuel portion and the combustion portion in the primary combustion chamber portion by joining a cap having a different cone size or thickness to the head of the saddle type solid rooster. It is possible to adjust the strength of combustion according to the height position of the fuel and the type and condition of the fuel,

According to a seventh aspect of the present invention, the secondary combustion chamber portion and the ash reservoir portion are formed large, and the fuel cylinder, the primary combustion chamber portion, and the combustion air supply chamber are provided therein. By the above, it is possible to obtain a combustion chamber that is kept warm with hot fuel and combustion air, and that efficient combustion is obtained with a small amount of fuel, and also the natural fall of scattered ash to the ash reservoir It works effectively and can send out clean hot air.

According to the eighth aspect of the present invention, an edge cutting plate for preventing a fuel shelving phenomenon is provided on the inside of the fuel cylinder and the additional frame fuel cylinder attached on the fuel cylinder, thereby achieving a stable and continuous supply of fuel. It is a feature.

As described above, according to the present invention, in the first aspect of the invention, in the primary combustion chamber portion, the primary combustion air is supplied from the combustion air holes of the inclined hearth and the primary combustion chamber portion wall, the pellets are burned downward, and the opening portion In addition to supplying secondary combustion air to the flame in the vertical solid rooster from the combustion air hole in the slope hearth near the center, it also serves to scatter ash into the vertical solid rooster. By burning the pellets, a red hot combustion layer of 850 ° C. or more is formed around the vertical solid roast, and the wood pyrolysis product gas and tar pass through it, resulting in higher temperature combustion and clean combustion exhaust gas, A highly efficient thermal energy combustion device is created.

In other words, to form a combustion layer with good breathability at the two points of the minimum necessary conditions for pellet combustion with a vertical solid roast and a sloped hearth. Combustion can be continued by three-dimensionally supplying combustion air from the slope hearth and the primary combustion chamber wall and scattering ash, enabling pellet combustion with natural ventilation.

All kinds of shaped granular and pelleted solid biomass fuel can be burned with a simple structure without electricity, and obtaining sufficient thermal energy can greatly expand the method of solar energy recycling.

Further, in the invention according to claim 2, the load on the red-hot combustion layer is prevented by providing an eaves on the combustion air hole to prevent the plugging of the hole with the pellet fuel and forming an inclined stepped hearth. By increasing the supply of combustion air and adjusting the direction of the combustion air hole to the direction of the slanted staircase, it is possible to secure the necessary and sufficient amount of air by ensuring the scattering of ash to the vertical solid rooster .

Further, in the invention according to claim 3, the slope hearth near the opening to the place where the flame in the vertical solid roast is burning so as to blow out through the opening to the secondary combustion chamber. The secondary combustion air is supplied into the flame while the ash is scattered from the combustion air holes, and the combustion gas stays in the secondary combustion chamber for about 2 seconds to secondary combustion and become clean combustion exhaust gas. At this time, the amount and ratio of primary combustion air and secondary combustion air differ depending on the type of pellet and tree species, so the amount and ratio of the fuel can be set to achieve the complete secondary combustion in pellet combustion. .

In the invention of claim 4, since the primary combustion chamber and the sloped hearth are on average about 850 ° C. to 900 ° C., distortion and thinning can be caused by metal fatigue and oxidation, thereby shortening the life of the apparatus. . Therefore, by using the refractory heat insulating material, the metal can be protected and the combustion temperature of the fuel can be kept high. And the ability to burn various types of fuel at a temperature of 800 ° C. or higher also enables dioxin countermeasures.

In the invention according to claim 5, a combustion air supply chamber is provided that surrounds and joins the fuel cylinder and the primary combustion chamber and communicates with the combustion air hole. By providing a chamber, the amount of air can be adjusted by adjusting the inlet and outlet, the supply pressure can be made constant, and if a blower is attached to the combustion air supply chamber, the strength of the combustion can be adjusted by the strength of the blown air Therefore, the apparatus can be miniaturized and can generate a large amount of heat.

Moreover, in invention of Claim 6, it was what put out the rostral cap to the head of the saddle-shaped solid rooster, and it was put out as a flame just under the rooster inside from the head by joining the cap until then. All the parts are removed and the flame is emitted from the side of the rooster under the cap to the inside and blown out through the opening to the secondary combustion chamber. This promotes air out of the combustion air holes and improves combustion and ash scattering. In addition, the height of the hem of the cap can be adjusted to adjust the height of the boundary between the fuel part and the red-hot combustion part. You can adjust the strength.

Further, in the invention according to claim 7, the secondary combustion chamber portion and the ash reservoir portion are largely formed, and the fuel cylinder, the primary combustion chamber portion, and the combustion air supply chamber are provided therein. The fuel, combustion air, and combustion chamber are heated with the secondary combustion heat, and efficient combustion is achieved, and the secondary combustion chamber and ash reservoir are made large. It is easy to descend, can reliably process the combustion ash, and can send clean hot air to the heat exchange equipment.

At this time, if a screw feeder is connected to the fuel supply, a blower is connected to the combustion air supply chamber, and a roasting cap is provided with a rooster cap, it can be used as a burner furnace or a gasification furnace.

Further, in the invention according to claim 8, a thin metal plate is placed inside the fuel cylinder and the additional frame fuel cylinder formed on the fuel cylinder so as to fill the diagonal of the cylinder, and both sides and the center are arranged vertically. By partitioning with a thin metal plate, it is just a combination of Roman letters H and T, and by setting an edge cutting plate that combines O and I, the grains are roughly aligned, When the mass is heavy, the fuel can form a scrum to prevent the shelf hanging phenomenon or the bridge phenomenon that does not drop naturally, and smooth fuel supply can be performed. Combustion can be realized.

Pellet combustion is possible with natural ventilation without using electricity, and the desired thermal power can be obtained when the lifeline is cut or when the work shed in the remote area where electricity is not conducted or recycling circulation proceeds and inexpensive pellets Pellet stoves that can also be used as wood-burning stoves are conceivable as heating and cooking heating devices in areas where fuel is available, and will be described as Example 1 with reference to FIGS.

In addition, when electricity is used and a screw feeder and a blower are used, a boiler burner is conceivable. In this case, scattering and adhesion of ash into the boiler, which is the biggest problem of the pellet burner so far, is reduced. The apparatus can be miniaturized and will be described as a second embodiment with reference to FIG.

The present invention is not limited to the above embodiment, and can be applied and used as a hot stove for a dryer or a gasifier for solid biomass, and various applications can be made by appropriately changing the structure, material, and the like. Possible use.

In the embodiment shown in FIGS. 1 to 6, the stove body 1 is composed of a chimney portion 5 made of a metal plate and provided with a tambar 6. On the front surface of the stove body 1, there are an ignition port 7 and a stove door 2. A heat resistant glass window 4 and a main body air intake adjustment port 3 are attached to the stove door 2 so that the inside can be seen.
There are combustion air intake control ports 8 for pellet combustion soot on both sides of the stove body 1.
The fuel cylinder 9 of the combustion apparatus of the present invention is joined to the upper surface of the stove body.
A primary combustion chamber portion 10 is formed integrally with the fuel cylinder 9, and a downward combustion opening 11 leading to the secondary combustion chamber portion 12 and the ash reservoir portion 13 is provided at the center of the bottom of the hearth bottom of the primary combustion chamber portion 10. It is provided, and the saddle-shaped solid rooster 14 is provided to cover the opening 11 and to provide a space on the opening 11, and the opening 11 extends between the opening 11 and the inner wall of the primary combustion chamber 10. The slope hearth 15 is formed so as to have a mortar shape centering on the slope hearth 15, and the slope hearth 15 is provided with the slope hearth 15 from the combustion air supply chamber 17 provided so as to cover the primary combustion chamber portion 10. , There are combustion air holes 16, and the combustion air holes 16 circulate in one horizontal row so as to surround the saddle-shaped solid rooster 14, and several stages are provided. In addition, combustion air holes 16 are provided on the wall of the primary combustion chamber 10 so as to make one round in a horizontal line up to the height of the saddle-shaped solid rooster 14.
The combustion air supply chamber 17 communicates with the combustion air intake adjusting port 8 and the air heating chamber 18 and supplies the combustion air to the primary combustion chamber portion 10 through the combustion air hole 16. The configuration is as described above.

The stove is used in a natural ventilation system in which the fuel cylinder lid 9a is opened and the pellets are inserted up to the height of the vertical solid rooster 14 and a chimney draft is used. Therefore, the stove door 2 is opened and the stove main body 1 is opened. Like a wood-burning stove, the fire is heated with a thin branch or the like, and the stove body 1 and the chimney 5 are heated by burning a thin branch or firewood so that the chimney works with a draft. When the stove main body 1 can be ignited and the draft is sufficiently activated, the pellet is ignited through the combustion air hole 16 by the cassette burner from the ignition port 7, and the combustion air intake adjustment port 8 is opened. Encourage the burning of the pellet E, and when the downward flame comes out, close the main body air intake control port 3 attached to the stove door 2 of the stove body 1 and switch to pellet combustion. .
Thereafter, the pellet E is filled into the fuel cylinder 9 and the combustion is continued.
In the downward combustion, as long as the fuel does not run out, it burns alone.

Flame F and ash G are blown out through the opening 11 into the secondary combustion chamber 12 through the bowl-shaped three-dimensional rooster 14, and the ash G descends to the ash reservoir 13 and accumulates in the ashtray 13a. The flame F collides with the baffle plate 19 while performing secondary combustion, becomes combustion gas Ha, and is discharged outside through the chimney 5.
Thereby, the stove main body 1 is heated and radiated as radiant heat.

FIG. 5 and FIG. 6 are edge cutting plates that are inserted into the fuel cylinder 9 or attached to the fuel cylinder 9 on the inside of the additional frame fuel cylinder 9b diagonally and fixed with clasps. From the shape, they are the H · T type edge cutting plate 20 and the O · I type edge cutting plate 21.
It is useful for preventing the shelf hanging phenomenon when you want to burn continuously for a long time or when the mass of raw materials is heavy.

In the pellet burner of FIG. 7, the burner furnace main body 22 has a large size of the secondary combustion chamber 12 and the ash reservoir 13, and the inner wall is protected by a refractory heat insulating material 15a to suppress heat radiation to the outside of the furnace. It plays the role of keeping the inside high. The fuel cylinder 9, the primary combustion chamber portion 10, and the combustion air supply chamber 17 are provided therein, and the fuel supply to the fuel cylinder 9 is pushed by a screw feeder and supplied to the combustion air supply chamber 17. The air is supplied with pressure air by the blower 27, and is supplied so that the combustion air with pressure is blown out from the inclined floor furnace 15 and the combustion air holes 16 in the wall of the primary combustion chamber 10, from the opening 11. In the same way, a flame is blown out, a strong heating power is obtained, and the function of the burner is performed.
If the pressure adjusting combustion air hole 16a is provided in the wall of the fuel cylinder 9, the same air pressure as that of the primary combustion chamber portion 10 is applied from above the fuel pellet E, so that the pyrolysis gas is pushed downward and flashes back. Can be prevented.
Moreover, if the rooster cap 14a is made thick and the height is increased, a roasted ball effect comes out, and thermal decomposition is accelerated and a high heating power is obtained.
A baffle guide 23 is attached under the opening 11, the flame F is converged, the secondary combustion chamber 12 is sufficiently secondary burned, the ash G is lowered to the ash reservoir 13, and the inner wall of the burner furnace body 22 is raised. The heated flame F is retained in the baffle rolling plate 24 to clean the combustion gas Ha, and sent from the combustion gas outlet 25 to the heat exchanger.

The pellet burner is used by supplying pellet E into the primary combustion chamber 10 with a screw feeder 26, igniting the pellet E from the ignition port 7 through the combustion air hole 16 with a gas burner, and starting the blower 27 from low speed rotation. The temperature is increased to a high speed and the flame is stabilized and the temperature of the burner furnace body 22 is increased.
After that, when the temperature of the burner furnace body 22 rises and settles, the speed of the screw feeder 26 and the rotation of the blower 27 are matched in order to adjust to the necessary heating power, and stable combustion is continued.

  It is a pellet stove perspective view of Example 1 of the present invention.   It is sectional drawing of Example 1 of this invention.   It is sectional drawing of Example 1 of this invention.   It is a partial explanation sectional view of Example 1 of the present invention.   It is a partial explanation perspective view of Example 1 of the present invention.   It is a partial explanation perspective view of Example 1 of the present invention.   It is explanatory sectional drawing of Example 2 of this invention.

Explanation of symbols

E Pellet F Flame G Ash H Flow of combustion air Ha Combustion gas 1 Stove body 2 Stove door 3 Body air receiving adjustment port 4 Window 5 Chimney 6 Damper 7 Ignition port 8 Combustion air receiving adjustment port 9 Fuel cylinder 9a Fuel cylinder cover 9b Additional fuel cylinder 10 Primary combustion chamber portion 11 Opening portion 12 Secondary combustion chamber portion 13 Ash reservoir portion 13a Ashtray 14 Vertical solid rooster 14a Rooster cap 15 Slope hearth 15a Refractory insulation 16 Combustion air hole 16a Pressure-regulated combustion air hole 17 Combustion air supply chamber 18 Air heating chamber 19 Baffle plate 20 H / T type edge cutting plate 21 O / I type edge cutting plate 22 Burner furnace body 23 Baffle guide 24 Baffle rolling plate 25 Combustion gas outlet 26 Screw feeder 27 Blower

Claims (8)

In the downward combustion system in which fuel and combustion air with the structure of the fuel cylinder, primary combustion chamber, secondary combustion chamber, and ash reservoir from the top flow from top to bottom, the secondary combustion chamber is located at the center of the bottom of the primary combustion chamber. An opening that leads to the head and the ash reservoir is provided, and the opening is covered, and in order to provide a space above the opening, a bowl-shaped three-dimensional rooster with a hook turned upside down is placed, with the opening at the center. A mortar-shaped slope hearth is formed on the bottom of the primary combustion chamber, and a necessary and sufficient number of holes are provided in the slope hearth and the primary combustion chamber wall toward the vertical solid roast. Combustion device. An eaves is provided on the sloped hearth and the combustion air holes provided in the wall of the primary combustion chamber to form an inclined stepped hearth, and the direction of the combustion air holes is also inclined downward in accordance with the oblique stepped shape. The combustion apparatus according to claim 1, wherein The combustion air holes provided in the inclined hearth and the wall of the primary combustion chamber are set such that the amount and ratio of the primary combustion air and the secondary combustion air are set by the arrangement of the number of holes and the size of the holes. The combustion apparatus according to claim 1 or 2, wherein the combustion apparatus is characterized. The combustion apparatus according to any one of claims 1 to 3, wherein a fireproof heat insulating material is used for the slope hearth and the primary combustion chamber part wall. Surrounding and joining the fuel cylinder and the combustion chamber, and communicating with the combustion air hole, each combustion air hole is provided with a combustion air supply chamber for supplying combustion air at a constant pressure. The combustion apparatus according to any one of claims 1 to 4. The combustion apparatus according to any one of claims 1 to 5, wherein a conical or polygonal-shaped rooster cap and a roasted ball rooster cap are joined to a head of the saddle-shaped solid rooster. 7. The secondary combustion chamber portion and the ash reservoir portion are formed to be large, and the fuel cylinder, the primary combustion chamber portion, and the combustion air supply chamber are provided therein. The combustion apparatus of any one of these. 8. An edge cutting plate for preventing a fuel shelving phenomenon is provided inside the fuel cylinder and an additional frame fuel cylinder that can be attached to the fuel cylinder. Combustion equipment.

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