JPWO2019171466A1 - Rice husk burning device, grain drying system - Google Patents

Abstract

A combustion chamber that burns rice husks, a combustion plate that is provided in the combustion chamber and that can place rice husks to burn on the surface, and has a plurality of holes that penetrate between the front surface and the back surface; At least one of an air supply unit that supplies air into the combustion chamber through the holes, a rice husk introduction unit that introduces rice husks onto the combustion plate, a rake provided on the combustion plate, and a combustion plate or a rake. The rake is provided with a drive unit that rotationally drives one or the other and a discharge unit that is provided outside the combustion plate and discharges the rice husks.The rake is supported by the shaft unit that extends vertically from the surface of the combustion plate and the shaft unit. The support portions extending along the surface of the combustion plate, and the first rake portion and the first rake portion, which are supported by the support portions and move the ash of the rice husks burned on the combustion plate to the outside of the combustion plate, are ash. By the second rake part that moves the rice husks introduced from the rice husk introduction part to the location where the A fourth rake unit that moves the ash discharged outside the combustion plate to the discharge unit is provided.

Description

The present invention relates to a rice husk burning device and a grain drying system.

2. Description of the Related Art In a grain drying system for drying grains, a technique of burning rice husks, which is an example of biomass fuel, is known as a fuel for a combustion device that supplies a heat source for drying. As a technique related to such a rice husk burning device, a grain drying facility is known that can effectively utilize the thermal energy of the biomass burning hot air generated in the biomass burning furnace (see, for example, Patent Document 1).

In the grain drying equipment of Patent Document 1, a biomass combustion furnace that generates hot air based on the combustion heat of biomass fuel and the outside air taken in from the outside, and the hot air generated in the biomass combustion furnace are supplied via a hot air supply pipe. And a circulation type grain dryer having a grain drying unit.

International Publication No. 2013/057838

By the way, in a rice husk burning device, when the burning temperature is high or the burning time is long, the crystalline silica contained in the ash after burning the rice husks or the exhaust may contain soot. Therefore, in the rice husk combustor, in order to suppress the crystalline silica in the ash and the soot in the exhaust to reduce the health effects and the environmental load, it is necessary to appropriately manage the combustion temperature and the combustion time. Crystalline silica is classified by IARC (International Cancer Society) into a group 1 of carcinogens (chemical substances, mixtures, and environment which are carcinogenic to humans). Therefore, it is desirable in the work environment to suppress the production of crystalline silica.

Here, the crystallization initiation temperature of pure silica is 1400° C., but in the case of rice husks, the formation of crystalline silica such as cristobalite, tridymite, and quartz begins at 800° C. due to the relationship with the impurities contained therein. .. Therefore, in the conventional coal charcoal manufacturing apparatus, the charcoal is manufactured by keeping the combustion temperature as low as around 400° C. like smoldering combustion. In this method, the crystallization of silica does not occur because the combustion temperature does not reach the crystallization of silica. However, in this method, since the rice husks continue to burn in an incomplete state for a long time, unburned gases such as black smoke and carbon monoxide are generated, and the environmental load is large. Moreover, since the combustion temperature is low, it is difficult to use the energy of combustion heat.

On the other hand, there is also a research result that if the burning time of rice husks is appropriately controlled and the burning time is shortened, crystalline silica is not generated even at a high temperature of 900° C., for example. This method utilizes the fact that the volatilization of hydrocarbons contained in rice husk occurs at a lower temperature than the crystallization of silica, and the mechanism of action thereof is that the volatilization of hydrocarbons always occurs first. In this method, the combustion gas is cleaner than the former, and the combustion heat is high in temperature, so that there is an advantage that energy can be easily utilized. On the other hand, it is necessary to control the combustion progress process of the rice husk within a certain range so that the hydrocarbon content in the rice husk is gasified and the combustion reaction is interrupted before the crystallization of silica occurs.

Further, when the rice husk combustion device is regarded as a combustion device, it is desirable that the obtained amount of heat be wider, and that the time variation of the amount of heat generated is smaller. Therefore, it is desirable to stably realize optimal combustion in accordance with the supply amount of rice husk as fuel.

The present invention, in the rice husk combustion apparatus, while gasifying the carbon content in the rice husk, by performing the combustion control of the rice husk so as to complete the combustion reaction before crystallization of silica occurs, the effective use of the rice husk combustion heat, and It is an object of the present invention to provide a technology capable of achieving both a health effect and a reduction in environmental load, and a grain drying system using the technology.

The present invention relates to a combustion chamber that burns rice husks, a combustion plate that is provided in the combustion chamber and that can place rice husks to be burned on the surface, and that has a plurality of holes that penetrate between the front surface and the back surface, An air supply unit for supplying air to the inside of the combustion chamber through the holes of the combustion plate, a rice husk introduction unit for introducing the rice husk onto the combustion plate, a rake provided on the combustion plate, and the combustion plate or The rake includes a drive unit that rotationally drives at least one of the rakes and a discharge unit that is provided outside the combustion plate and discharges the rice husks.The rake includes a shaft portion that extends vertically from the surface of the combustion plate, and a shaft. And a first rake part supported by the supporting part and extending along the surface of the combustion plate, a first rake part supported by the supporting part, and moving the ash of the rice husks burned on the combustion plate to the outside of the combustion plate. Supported by the first rake part, the second rake part that moves the husks introduced from the husk introduction part to the position where the ash has moved, and the second rake part that is supported by the support part A third rake portion that contacts the combustion plate and a fourth rake portion that is supported by the support portion and that moves the ash discharged outside the combustion plate by the first rake portion to the discharge portion.

Further, the present invention is a rice husk burning device that burns rice husks to generate heat by exchanging heat, a grain dryer that dries grains with the hot air generated by the rice husk burning device, and a rice husk burning device. And a duct for sending hot air to the grain dryer, and the rice husk burning device is the above-mentioned rice husk burning device.

According to the present invention, in the rice husk combustion device, while effectively carbonizing the carbon content in the rice husk, by performing combustion control of the rice husk so as to complete the combustion reaction before crystallization of silica occurs, effective use of the rice husk combustion heat Also, it is possible to achieve both health effects and reduction of environmental load.

1 is a schematic configuration diagram showing a grain drying system in which a rice husk burning device according to an embodiment of the present invention is installed. It is a front view of a rice husk combustion device. It is a schematic diagram which shows the internal structure of a rice husk combustion apparatus. It is a top view showing the internal structure of a rice husk combustion device. It is a front view of a rake. It is a top view of a rake. It is a schematic diagram which shows the circumference|surroundings of the combustion plate after the rice husk is introduced. It is a top view which shows the circumference|surroundings of the combustion plate after the rice husk is introduced. It is a top view showing the circumference of a combustion plate when the 1st rake part moves ash of rice husks. It is a top view which shows the periphery of a combustion plate when a 2nd rake part moves a rice husk. It is a top view which shows the periphery of a combustion plate when a 3rd rake part stirs a chaff. It is a top view which shows the circumference|surroundings of a combustion plate when a 4th rake part discharges ash of a rice husk. It is a schematic diagram which shows the circumference|surroundings of a combustion plate when the 4th rake part discharges the ash of a rice husk. 4 is a table showing the composition of combustion ash in the examples. It is a table which shows the component of combustion ash in a reference example (conventional machine) and an example. Is a table showing the ratio of the reference example (prior art) and soluble silicic acid in a sample of ash in Example (S-SiO _2).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Structure of grain drying system]
FIG. 1 is a schematic configuration diagram showing a grain drying system 1 in which a rice husk burning device according to an embodiment of the present invention is installed. As shown in FIG. 1, the grain drying system 1 includes a rice husk combustion device 10, a rice husk supply device 20, a grain dryer 30, a warm air supply duct 40, a blower 50, a combustion air fan 60, and an exhaust fan. 70 and an exhaust chimney 80. In the present embodiment, an example in which the heat generated by the rice husk burning device of the present invention is used for grain drying will be described. The heat generated by the rice husk burning device of the present invention can be used for purposes other than grain drying, such as for heating.

The rice husk burning device 10 is a device that heats the rice husks by burning the rice husks that are the hulls of rice, which is an example of grain. The rice husk burning device 10 supplies the heat generated by burning the rice husks to a heat supply target such as the grain dryer 30. Details of the rice husk burning device 10 will be described later.

The rice husk supply device 20 is a device that supplies rice husk during the operation of the rice husk combustion device 10. The rice husk supply device 20 includes a hopper that stores rice husks, a supply path such as a screw that conveys the rice husks from the hopper to the rice husk combustion device 10, and power supplied from the hopper.

The grain dryer 30 is a device for drying grains such as rice by the heat generated by the rice husk burning device 10. Although two grain dryers 30 are provided in FIG. 1, the number of grain dryers 30 is not limited in the present invention.

The hot air supply duct 40 is a duct for sending the hot air heated by the heat generated by the rice husk combustion device 10 to the grain dryer 30. The warm air supply duct 40 is formed of a material corresponding to the temperature of the warm air sent to the grain dryer 30 and a size corresponding to the supply amount.

The blower 50 is attached to the side surface of the rice husk combustion device 10. The air blown by the blower 50 passes between the exterior body 11 and the combustion chamber 14 and is discharged from the warm air supply port 13. The blower 50 sends air into the heat exchanger provided in the upper part of the rice husk combustion device 10. The air sent to the heat exchanger is heat-exchanged with the heat generated in the rice husk combustion device 10 to become warm air, which is sent to the grain dryer 30. The combustion air fan 60 sends in the air necessary for the combustion of the rice husks by the rice husk combustion device 10 from the outside. The combustion air fan 60 controls the combustion state of the rice husk combustion device 10 by controlling the amount of air sent to the rice husk combustion device 10.

The exhaust fan 70 is provided at the tip of the exhaust chimney 80 extending from the upper portion of the rice husk combustion device 10. The exhaust fan 70 guides the combustion gas in the combustion chamber of the rice husk combustion device 10 to the heat exchanger and exhausts it. The exhaust fan 70 sets a negative pressure in the combustion chamber to prevent the exhaust gas from leaking to the air flow path other than the exhaust chimney 80. The exhaust fan 70 controls the amount of air to be exhausted, that is, the number of revolutions, so that hot air having an arbitrarily set temperature can be output from the hot air supply port 13.

In addition, in the grain drying system 1, the configurations of the rice husk supply device 20 and the blower 50 are not limited to the examples described above, and various forms can be used.

[Configuration of rice husk burning device]
Next, an example of the configuration of the rice husk combustion device 10 will be described.

FIG. 2 is a front view of the rice husk combustion device 10. FIG. 2 is a view of the rice husk combustion device 10 viewed from a direction opposite to the extending direction of the hot air supply duct 40 in FIG. 1. Hereinafter, the rice husk burning device 10 will be described with the surface facing the extending direction of the hot air supply duct 40 as the front surface. As shown in FIG. 2, the rice husk combustion device 10 includes an outer casing 11, a rice husk introduction portion 12, and a hot air supply port 13. The rice husk combustion apparatus 10 heats air by burning rice husks, which is an example of biomass combustion.

The outer casing 11 forms the outer shape of the rice husk combustion device 10. The outer casing 11 is composed of a panel 111 for partitioning the inside and outside of the rice husk combustion device 10 in order to accommodate the components of the rice husk combustion device 10 such as a combustion chamber described later, and a frame 112 for holding the components and determining the outer shape of the device. It

The rice husk introduction part 12 is a member for supplying the rice husks supplied from the rice husk supply device 20 to the inside of the combustion chamber.

The warm air supply port 13 is an opening for sending the heat-exchanged warm air to the warm air supply duct 40. The warm air supply port 13 communicates with the warm air supply duct 40.

FIG. 3 is a schematic diagram showing the internal structure of the rice husk combustion device 10. As shown in FIG. 3, the rice husk combustion device 10 includes a combustion chamber 14, a drive unit 17, a discharge unit 18, and an air supply unit 19 inside the exterior body 11.

The combustion chamber 14 constitutes a space for burning the rice husks. The combustion chamber 14 is made of a material that can withstand the burning of rice husks. The combustion chamber 14 is provided with a combustion plate 15 and a rake 16 in the space for burning the rice husks.

The combustion plate 15 is provided inside the combustion chamber 14. The surface of the combustion plate 15 is, for example, a flat surface so that the chaff to be burned can be placed.

FIG. 4 is a plan view showing the vicinity of the combustion plate 15 of the rice husk combustion device 10. As shown in FIG. 4, the combustion plate 15 is formed, for example, in a circular shape in a plan view in accordance with the shape and the operating range of the rake 16. The combustion plate 15 includes a combustion table 151 and a combustion plate body 152. The combustion table 151 is supported by the panel 111. The combustion table 151 is formed in a cylindrical shape. The combustion table 151 has a combustion plate body 152 mounted thereon. The combustion table 151 makes the height of the combustion plate body 152 higher than the bottom surface of the combustion chamber 14.

The combustion plate body 152 is made of a heat-resistant material such as a heat-resistant ceramic plate for placing rice husks that are burned at a high temperature on the surface thereof. As for the ceramic plate forming the combustion plate body 152, the entire combustion plate body 152 may be formed of a single plate, or a plurality of plates may be arranged side by side. The combustion plate body 152 is a ceramic punching metal plate member having a plurality of holes penetrating between the front surface and the back surface. The holes in the combustion plate body 152 allow air to pass between the front surface and the back surface.

The combustion plate body 152 is not limited to the ceramic punching metal shape as described above, and may be, for example, an air-permeable ceramic porous plate material, or a material other than ceramic that can withstand high temperatures. But it's okay. Further, the planar shape of the combustion plate body 152 is not limited to the circular shape described above.

An air chamber 153 is formed inside the combustion plate 15 by the combustion table 151 and the combustion plate body 152 provided on the panel 111. The air chamber 153 is filled with air supplied from the combustion air fan 60 via the air supply unit 19. The air in the air chamber 153 is discharged upward (to the surface of the combustion plate body 152) through the holes of the combustion plate body 152.

The tip part of the rice husk introduction part 12 is arranged above the vicinity of the center of the combustion plate 15. For this reason, the rice husk introduction part 12 can introduce the rice husk onto the vicinity of the center of the combustion plate 15. The rice husk introduction part 12 can supply a necessary amount (for example, 7 to 60 kg/h) of rice husk with respect to a set temperature. The amount of rice husks input is arbitrarily determined, for example, when the rice husk combustion device 10 is started or operated.

The rice husk introduction unit 12 continuously inputs the rice husks. If the amount of rice husks to be charged is 60 kg/h, for example, 1 kg of rice husks is charged for 60 minutes per minute. The rice husk introduction unit 12 is provided with a mechanism such as a screw conveyor (not shown) that realizes continuous introduction of the rice husk per time at the root of the rice husk introduction unit 12. The rice husk introduction part 12 controls the input amount of rice husks by controlling the rotation speed of the screw conveyor. The rice husk burning device 10 can control the burning temperature and the burning time of the rice husks by adjusting the number of revolutions of the rake 16 and the input amount of the rice husks.

The rake 16 is provided on the combustion plate 15. The rake 16 includes a shaft portion 161, a support portion 162, a first rake portion 163, second rake portions 164 and 164b, a third rake portion 165, and fourth rake portions 166 and 167.

FIG. 5 is a front view of the rake 16. Further, FIG. 6 is a plan view of the rake 16. As shown in FIGS. 5 and 6, in the rake 16, the shaft portion 161 is located substantially at the center of the combustion plate 15. The support portion 162 is attached so as to be oriented at a right angle or a substantially right angle with respect to the shaft portion 161. The shaft portion 161 is attached near the midpoint of the support portion 162. The length of the support portion 162 is longer than the diameter of the combustion plate body 152. The rake 16 is formed in a substantially T shape in which the length of the support 162 is longer than the length of the shaft 161.

With the above-described shape, the rake 16 extends vertically from the surface of the combustion plate body 152 of the combustion plate 15 in the state where the rake 16 is attached to the rice husk combustion device 10 as shown in FIGS. 3 and 4. The support 162 extends along the surface of the combustion plate body 152.

The first rake portion 163 is provided at an end portion of a substantially columnar first support member 163a whose one end in the longitudinal direction extends from the support portion 162 in the extending direction of the shaft portion 161. The first rake portion 163 is a substantially rectangular plate material. The first rake portion 163 is provided such that the long side thereof is substantially parallel to the combustion plate body 152 when the rake 16 is attached to the combustion plate 15. Therefore, the first rake portion 163 and the first support member 163a form a substantially L shape.

The second rake portion 164 is a substantially rectangular plate material. The second rake portion 164 is provided such that the long side thereof is substantially parallel to the combustion plate body 152 when the rake 16 is attached to the combustion plate 15. The second rake portion 164 is supported by the end portion of a substantially columnar second support member 164a extending from the support portion 162 in the extension direction of the shaft portion 161. The second rake portion 164b is a substantially rectangular plate material. The second rake portion 164b is provided such that the long side thereof is substantially parallel to the combustion plate body 152 when the rake 16 is attached to the combustion plate 15. One end of the second rake portion 164b extends vertically from the shaft portion 161, and the other end is supported by the second support member 164a. The second rake portion 164b may be formed of a round bar material.

The third rake portion 165 is, for example, a round bar material. The third rake portion 165 may be a square bar material. The third rake portion 165 is provided such that, when the rake 16 is attached to the combustion plate 15, the long side is substantially parallel to the combustion plate body 152. The third rake portion 165 is supported by the shaft portion 161 and an end portion of a substantially columnar third support member 165 a extending from the support portion 162 in the extending direction of the shaft portion 161.

The fourth rake portion 166 is a substantially rectangular plate material. The fourth rake portion 166 is provided such that the long side thereof is substantially parallel to the combustion table 151 when the rake 16 is attached to the combustion plate 15. The fourth rake portion 166 is provided on the fourth support member 166a extending from one end of the support portion 162 in the extending direction of the shaft portion 161.

The fourth rake part 167 is a substantially rectangular plate material. The fourth rake portion 167 is provided such that the long side thereof is substantially parallel to the combustion table 151 when the rake 16 is attached to the combustion plate 15. The fourth rake portion 167 is provided on the fifth support member 167a extending from the other end of the support portion 162 in the extending direction of the shaft portion 161.

The extending direction of the shaft portion 161 from the support portion 162 is also the direction in which the combustion plate body 152 is present when the rake 16 is attached to the combustion plate 15. The first rake portion 163, the second rake portions 164, 164b, the third rake portion 165, and the fourth rake portions 166, 167 are formed of a hard and heat-resistant member such as a metal plate material. The shapes of the first rake portion 163, the second rake portions 164, 164b, the third rake portion 165, and the fourth rake portions 166, 167 are not limited to the above-mentioned materials.

Positions of the first rake portion 163, the second rake portions 164, 164b, and the third rake portion 165, whose longitudinal faces face substantially parallel to the combustion plate body 152 when the rake 16 is attached to the rice husk combustion device 10. It is provided in. The first rake portion 163, the second rake portion 164, and the third rake portion 165 come into contact with the rice husks and ash on the combustion plate body 152 during operation of the rice husk combustion device 10. The first rake portion 163 and the third rake portion 165 are set such that their lowermost ends do not abut the upper surface of the combustion plate body 152, that is, the mounting positions are set so that ash having a predetermined thickness remains. .. Here, assuming that the amount of air sent to the inside of the combustion chamber 14 is determined by the air permeability of the combustion plate body 152 containing ash, the position where the first rake portion 163 and the third rake portion 165 are attached is determined as follows. It is desirable that the distance between the lowermost end of the rake 16 and the upper surface of the combustion plate body 152 be, for example, about 2 to 5 cm so that the height has an appropriate value (for example, 1 to 5 cm).

The second rake portion 164 is shorter than the first rake portion 163 and the third rake portion 165 in the vertical direction (shorter direction) from the support portion 162, for example, by about 10 mm. Therefore, the second rake portion 164 has a larger gap between the rake 16 and the combustion plate body 152 when the rake 16 is attached to the rice husk combustion device 10, as compared with the first rake portion 163 and the third rake portion 165. The second rake portion 164b is shorter than the second rake portion 164 in the vertical direction (shorter direction) from the support portion 162 by, for example, about 10 mm. Therefore, the second rake portion 164b has a larger gap between the rake 16 and the combustion plate main body 152 when the rake 16 is attached to the rice husk combustion device 10, as compared with the second rake portion 164.

The fourth rake portions 166 and 167 are provided at positions facing the combustion table 151 when the rake 16 is attached to the rice husk combustion device 10. Therefore, the fourth rake portions 166 and 167 come into contact with the ash dropped from the combustion plate body 152 onto the upper surface of the combustion table 151 during the operation of the rice husk combustion device 10.

The positions of the end portions of the rakes 16 closer to the respective shaft portions 161 viewed from the shaft portions 161 are the third rake portion 165, the second rake portion 164, the first rake portion 163, the fourth rake portions 166, 167 in that order. Will be placed.

The first rake portion 163 is attached at an angle θ1 with respect to the support portion 162 with the support portion 162 as a starting point when viewed from a direction (direction of FIG. 6) facing the extending direction of the shaft portion 161. Here, the angle θ1 is, for example, 45° forward tilt toward the rotation direction of the rake 16. Similar to the first rake portion 163, the second rake portion 164 is also attached to the support portion 162 at an angle θ2 with the support portion 162 as a starting point when viewed from the direction facing the extending direction of the shaft portion 161. Here, the angle θ2 is, for example, 45° backward tilt with respect to the rotation direction of the rake 16. The first rake portion 163 and the second rake portion 164 have angles in opposite directions with respect to the support portion 162.

The third rake portion 165 is attached parallel to the support portion 162 when viewed from a direction facing the extending direction of the shaft portion 161, that is, in a plan view. The orientation of the third rake portion 165 is not limited to this, and the third rake portion 165 may be attached at an angle to the support portion 162 in a plan view.

The fourth rake portions 166 and 167 are attached in parallel with the support portion 162 when viewed from a direction facing the extending direction of the shaft portion 161. The fourth rake portions 166 and 167 are provided at both ends of the support portion 162. The length of the fourth support member 166a that supports the fourth rake portion 166 and the length of the fifth support member 167a that supports the fourth rake portion 167 comes into contact with the ash that has dropped from the combustion plate body 152 onto the upper surface of the combustion table 151. Therefore, the length of the first rake portion 163, the second rake portion 164, and the third rake portion 165 from the support portion 162 is longer than that of the support member. The lengths of the fourth support member 166a and the fifth support member 167a are longer than the support members of the first rake portion 163, the second rake portion 164, and the third rake portion 165 by a length corresponding to the height of the combustion table 151. ..

As shown in FIG. 3, the drive unit 17 is arranged below the back surface of the combustion plate 15. The rotary shaft of the drive unit 17 is connected to the shaft unit 161 by being provided coaxially with the shaft unit 161 of the rake 16. The drive unit 17 is configured by an electric motor, a gear, or the like in order to drive the rake 16 about the shaft. The drive unit 17 is, for example, a rake so that the rake 16 introduced as described above from the rice husk introduction unit 12 onto the combustion plate 15 can be discharged while the rake 16 configured as described above makes several revolutions around the combustion plate 15. Rotate 16 at a speed of about 6 seconds per revolution.

The discharge part 18 is provided outside the combustion plate 15. The discharge part 18 forms a path for discharging the chaff to the outside of the chaff combustion device 10. The discharge part 18 is provided to discharge the ash on the combustion table 151 collected by the fourth rake parts 166 and 167 to the outside of the rice husk combustion device 10. The discharge unit 18 is arranged on the moving line of the fourth rake units 166 and 167. The discharge part 18 is provided between the combustion table 151 and the combustion chamber 14 in a front view. The opening width of the discharge portion 18 is preferably as wide as the width of the fourth rake portions 166 and 167. In addition, the number of the discharge units 18 and the position in plan view are not limited to those in the present embodiment.

The air supply unit 19 takes in the air taken in from the combustion air fan 60 shown in FIG. 1 into the rice husk combustion device 10. The air supply unit 19 supplies the air taken in from the combustion air fan 60 to the inside of the combustion chamber 14 from the back surface side of the combustion plate body 152 of the combustion plate 15 through the hole provided in the combustion plate body 152.

[Operation of rice husk burning device]
Next, an example of the operation of the rice husk combustion device 10 will be described. In the rice husk combustion device 10, ignition of the rice husk at the start of operation is performed by charging fuel such as kerosene and a pilot fire. The method of igniting the rice husks at the start of operation is not particularly limited.

FIG. 7 is a schematic view showing the periphery of the combustion plate 15 after the rice husk C is introduced. Further, FIG. 8 is a plan view showing the periphery of the combustion plate 15 after the rice husk C has been introduced. As shown in FIGS. 7 and 8, on the surface of the combustion plate body 152 of the combustion plate 15, the ash A of the rice husk that has been introduced into the inside of the combustion chamber 14 is accumulated. In the rice husk combustion device 10, the rice husk C is introduced from the rice husk introduction portion 12 to the surface near the center of the combustion plate 15. In this example, the rake 16 rotates in the direction of arrow R (counterclockwise) as shown in FIG.

FIG. 9 is a plan view showing the periphery of the combustion plate 15 when the first rake portion 163 moves the ash of the rice husk C. As described above, the first rake portion 163 is attached to the support portion 162 at an angle θ1 with the support portion 162 as the starting point when viewed from the direction facing the extending direction of the shaft portion 161. As shown in FIG. 9, the first rake portion 163 is provided with an angle θ1 that is inclined forward in the rotation direction, so that the ash A burned on the combustion plate 15 has a predetermined thickness. A portion of the ash A1 piled up above is pushed out and moved to the outside of the combustion plate 15, that is, in the direction of the combustion table 151. The first rake portion 163 is a plate member having a substantially rectangular shape, and thus is suitable for extruding and moving the ash A1. The first rake portion 163 has a smaller gap (lower attachment position) with the combustion plate body 152 when attached to the rice husk combustion device 10 than the second rake portion 164 for pushing out the ash A1. After the first rake portion 163 moves the ash A1, the recess H is formed. As the rake 16 continuously rotates, the first rake portion 163 scrapes out and discharges the ash A on the combustion plate body 152. The first rake portion 163 also has an action of stirring the ash A on the combustion plate main body 152 by rotating the rake 16 and continuously contacting the ash A.

FIG. 10 is a plan view showing the periphery of the combustion plate 15 when the second rake portion 164 moves the rice husk C. As described above, the second rake portion 164 is attached to the support portion 162 at an angle θ2 with respect to the support portion 162 as a starting point when viewed from the direction facing the extending direction of the shaft portion 161. As shown in FIG. 10, the second rake portion 164 is provided with an angle θ2 that is inclined rearward with respect to the rotation direction, so that the first rake portion 163 moves the ash A1 in the front in the rotation direction to form the concave portion. The rice husk C introduced from the rice husk introduction part 12 is moved to a place including a place where H is formed. The second rake portion 164 is a plate member having a substantially rectangular shape, and thus is suitable for pushing out the rice husk C to move it. The second rake portion 164 also has a function of stirring the ash A on the combustion plate body 152 by rotating the rake 16 and continuously contacting the ash A.

The 2nd rake part 164b pushes the chaff C thrown into the center vicinity of the combustion plate main body 152 to the front side of the 2nd rake part 164 located outside the 2nd rake part 164b. The second rake portion 164b flattens the rice husk C on the combustion plate body 152. The second rake portion 164b stirs the chaff C on the combustion plate body 152 when the supply amount of the chaff C is small. When the second rake portion 164b is attached to the rice husk combustion device 10 more than other rake portions in order to weaken the action of pushing the rice husk C near the center of the combustion plate body 152 when the supply amount of the rice husk C is large. Is large (the mounting position is high).

FIG. 11 is a plan view showing the periphery of the combustion plate 15 when the third rake portion 165 agitates the chaff C. As shown in FIG. 11, the third rake portion 165 contacts the rice husk C and the ash A that the second rake portion 164 has moved to the recess H and its vicinity. The third rake portion 165 evens the rice husk C so that it spreads over the combustion plate 15 as the rake 16 rotates. In addition, the third rake part 165 changes the positions of the rice husk C and the ash A on the combustion plate body 152 by contacting the rice husk C and the ash A which are in contact with each other, and the rice husk C and the combustion which are put into the combustion plate main body 152. Stir rice husk C and ash A therein. The third rake portion 165 has a smaller distance (lower attachment position) from the combustion plate body 152 when attached to the rice husk combustion device 10 than the other rake portions in order to agitate the rice husk C. Further, since the third rake portion 165 is formed of a round bar material, the action of pushing out the rice husk C is weakened. By the second rake unit 164 stirring the rice husk C and the ash A, the rice husk combustion device 10 can improve the combustion state of the rice husk C.

FIG. 12 is a plan view showing the periphery of the combustion plate 15 when the fourth rake parts 166, 167 discharge the ash A2 of rice husk. Further, FIG. 13 is a schematic diagram showing the periphery of the combustion plate 15 when the fourth rake parts 166 and 167 discharge the ash A2 of rice husks. As described above, the fourth rake portions 166 and 167 are attached to the outside of the combustion plate body 152 in the width direction and to the positions closer to the surface of the combustion table 151 than the combustion plate body 152 in the height direction. As shown in FIGS. 12 and 13, the fourth rake portions 166 and 167 move the ash A2 discharged to the outside of the combustion plate body 152 by the first rake portion 163 to the discharge portion 18. The ash A2 moved to the discharge unit 18 is discharged to the outside of the rice husk combustion device 10.

In addition to rotating the rake 16 configured as described above at an arbitrary rotation speed, as described above, the rotation speed of the rake 16 is tuned to the amount of rice husks introduced by the rice husk introduction section 12 (rotational speed of the screw conveyor). By performing such control, the rice husk combustion device 10 can control the period during which the rice husks stay on the combustion plate 15, that is, the burning time and the amount of the rice husks. The rice husk combustion device 10 rotates the rake 16 at an arbitrary rotation speed to supply the necessary amount (7 to 60 kg/h) to the set temperature, and the accumulated amount of the rice husks on the combustion plate 15 is supplied. And the deposition thickness (1-5 cm) can be kept constant. In addition, by providing the rake 16, the rice husk combustion device 10 stabilizes the thickness of the rice husks and ash on the combustion plate body 152, and the air supply amount required for combustion by the combustion air fan 60 is adjusted in accordance with the rice husk supply amount. By controlling the exhaust amount by the exhaust fan 70, the combustion temperature and the combustion time can be appropriately managed. The air supply amount of the combustion air fan 60 may be constant.

Here, the crystallization initiation temperature of pure silica is 1400° C., but in the case of rice husks, the formation of crystalline silica such as cristobalite, tridymite, and quartz begins at 800° C. due to the relationship with the impurities contained. .. On the other hand, there is also a research result that if the combustion time is appropriately controlled to be a short combustion time, the formation of crystalline silica does not occur even at a high temperature of 900° C.

Therefore, in order to maximize the heat of combustion without producing crystalline silica when the rice husk is burned, it is necessary to appropriately control the combustion temperature and the combustion time.
[Example]

The analysis result of the ash sample of the rice husk after burning by the rice husk burning device 10 will be described as an example. The reference example shows the analysis result of the ash sample of the rice husk after burning by the conventional rice husk burning device. Here, the following ash samples are obtained by burning rice husks cultivated in the fields of general farmers in Shizuoka Prefecture, Japan.

FIG. 14 is a table showing the composition of combustion ash in the examples. FIG. 15 is a table showing components of combustion ash in the reference example (conventional machine) and the example. In FIG. 15, samples of combustion ash (No. 1 to No. 5) in which the input amount of rice husks in the example is different, commercially available coal charcoal (NO. 6) as a reference example, and combustion ash during operation of a conventional machine The ratio of crystalline silica, quartz, cristobalite, and tridymite contained in each of (No. 7) and combustion ash after operation (No. 8) is shown. FIG. 16 is a table showing the ratio of soluble silicic acid (S—SiO ₂ ) in the samples of the combustion ash in the reference example (conventional machine) and the example. In FIG. 16, samples of combustion ash (No. 1 to No. 5) having different amounts of rice husks in the examples, commercially available coal charcoal (NO. 6) as a reference example, and combustion ash (NO. 7) of a conventional machine. The ratio of soluble silicic acid contained in each of the above) is shown.

14 and 15, it can be seen that the ash after burning the rice husks according to the example of the rice husk burning device 10 has a low concentration of crystalline silica near the measurement limit, unlike the ash of the reference example. .. Therefore, according to the rice husk burning device 10, the dust generation evaluation is as low as 1.1%, and the ash scattering property is considered to be small, so that it is understood that the influence on the human body is extremely small.

Moreover, according to FIG. 14 and FIG. 16, although the ash after the burning of the rice husks according to the example of the rice husk burning device 10 has a concentration of soluble silicic acid of 20% to 30% in the case of the reference example. By comparison, it can be seen that the value is as high as 50%. Therefore, according to the rice husk burning device 10, the ash after burning can be expected to be used as a soil improving material.

Further, according to FIG. 15, the ash after the burning of rice husks according to the example of the rice husk burning device 10 has a concentration of crystalline silica even if the amount of supplied rice husks changes (8.6 to 59.6 kg/h). It can be seen that the value is lower than the measurement limit.

Further, according to FIG. 16, the ash after the burning of the rice husks according to the example of the rice husk burning device 10 has a concentration of soluble silicic acid even if the amount of supplied rice husks is changed (8.6 to 56.6 kg/h). It can be seen that the high value is close to 50%.

As described above, according to the rice husk burning device 10 according to the present embodiment, by properly managing the burning temperature and the burning time of the rice husk, it is possible to reduce harmful substances, reduce health effects and environmental load. ..

[Other Embodiments]
In the present embodiment, the rake 16 is rotated by the drive unit 17 on the surface of the combustion plate 15. However, the present invention is not limited to this, and for example, the rake is fixed by the shaft to rotate the combustion plate. Therefore, the rice husks may be stirred and moved.

Further, the combustion plate 15 may have a surface other than a flat surface, for example, a gently curved surface or some unevenness, as long as it does not affect the burning of the rice husk and the stirring or movement of the rice husk and ash by the rake 16.

Further, although the second rake portion 164 and the third rake portion 165 are composed of separate members, the present invention is not limited to this, and the functions of the above-described second rake portion 164 and third rake portion 165 are not limited to this. It may be integrally configured so as to be obtained by one rake portion.

The first rake portion 163, the second rake portion 164, the third rake portion 165, and the fourth rake portions 166 and 167 provided in the rake 16 are supported by the shaft portion 161 which is a single power shaft as described above. The rotation axis of each rake portion may be different, for example. In addition, although the number of the rakes 16 on the combustion plate 15 is one in the present embodiment, two or three rakes 16 may be arranged.

The rice husk burning device described above can also apply the obtained heat to applications other than the drying of grains, such as heating. Further, the rice husk burning device described above can be applied to the case where the ash of rice husk is used as a coal improving agent, that is, as a soil improving material without using heat. Further, the rice husk burning device described above can also be applied to biomass materials such as wood pellets and rice straw cut to a length of 3 to 5 cm.

1: Grain drying system 10: Rice husk combustion device 11: Exterior body 12: Rice husk introduction part 13: Hot air supply port 14: Combustion chamber 15: Combustion plate 16: Rake 17: Drive part 18: Ejection part 19: Air supply part 20 : Rice husk supply device 30: Grain dryer 40: Warm air supply duct 50: Blower 60: Combustion air fan 70: Exhaust fan 80: Exhaust chimney 111: Panel 112: Frame 151: Combustion table 152: Combustion plate body 153: Air Chamber 161: Shaft 162: Support 163: First Rake 163a: First Support Member 164: Second Rake 164a: Second Support 164b: Second Rake 165: Third Rake 165a: Third Support Member 166: 4th rake part 166a: 4th support member 167: 4th rake part 167a: 5th support member

Claims (8)

A combustion chamber that burns rice husks,
A combustion plate that is provided in the combustion chamber, has a plurality of holes that can be placed on the surface of the rice husk to be burned, and that penetrates between the front surface and the back surface,
An air supply unit that supplies air to the inside of the combustion chamber by passing through the holes of the combustion plate from the back surface of the combustion plate;
A rice husk introduction part for introducing the rice husks onto the combustion plate,
A rake provided on the combustion plate,
A drive unit that rotationally drives at least one of the combustion plate and the rake,
A discharge portion provided outside the combustion plate for discharging the rice husks;
Equipped with
The rake is
A shaft extending vertically from the surface of the combustion plate,
A support portion supported by the shaft portion and extending along the surface of the combustion plate;
A first rake part supported by the support part, for moving ash of the rice husks burned on the combustion plate to the outside of the combustion plate;
A second rake part that is supported by the support part and moves the rice husks introduced from the rice husk introduction part to a location where the first rake part has moved the ash;
A third rake part supported by the support part and in contact with the rice husks moved by the second rake part on the combustion plate;
A fourth rake part that is supported by the support part and moves the ash discharged to the outside of the combustion plate by the first rake part to the discharge part;
With
Rice husk burning device. The rake is
From the shaft portion, the third rake portion, the second rake portion, the first rake portion, and the fourth rake portion are supported by the support portion in this order.
The rice husk combustion device according to claim 1. The second rake portion has a shorter vertical distance from the support portion than the first rake portion and the third rake portion,
The rice husk combustion device according to claim 1. The first rake part and the second rake part are
It is attached at an angle to the support portion when viewed from a direction parallel to the shaft portion,
The rice husk burning device according to claim 1. The combustion plate is a porous material,
The rice husk combustion device according to claim 1. The rice husk combustion device according to claim 1, wherein the air supply unit is provided below the combustion chamber. The rake is provided with the shaft coaxially with the center of the combustion plate in a plan view,
The rice husk combustion device according to claim 1. A rice husk burning device that burns rice husks to generate heat by exchanging heat.
A grain dryer for drying grains by the hot air generated by the rice husk burning device,
A duct that sends the hot air generated by the rice husk burning device to the grain dryer,
Is a grain drying system comprising
The rice husk burning device,
The rice husk combustion device according to claim 1,
Grain drying system.