JP2017096554A - Wooden chip drying device and drying method for biomass power generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wooden chip drying device and drying method for biomass power generation capable of heating and drying wooden chips for a biomass power generation by hot air got through combustion of solid fuel such as wooden biomass and the like of low environmental burden in place of fossil fuel and capable of reducing volume of waste of pyroligneous acid generated by the biomass power generation.SOLUTION: This invention comprises a hot air generating furnace 2 provided with a secondary combustion chamber 17 having, at one end part of a kiln main body 12, a feeding shoot 14, a combustion assisting burner 15 and a combustion air supply fan 16, and at the other end part, an atomization nozzle 24 for atomizing pyroligneous acid generated as biomass power generation occurs, and a heating drying furnace 3 having at one end part of a kiln main body 43, a biomass power generating wooden chip feeding screw feeder 46 and scraping blades 42 arranged at its inner peripheral wall are installed side by side and these hot air generating furnace 2 and the heating and drying furnace 3 are connected by a hot air supply duct 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a drying apparatus and a drying method for heating and drying an object to be dried by hot air generated by burning solid fuel, and more particularly to a drying apparatus and a drying method for heating and drying wood chips for biomass power generation.

  In recent years, in order to prevent global warming and effectively use resources, raw wood such as waste timber and thinned wood that has been cut out and discarded from forests and disposed of as chips is used as biomass fuel. 2. Description of the Related Art A biomass power generation system that generates power by rotating a steam turbine with high-pressure steam generated by combustion in a boiler is drawing attention.

  By the way, raw wood such as waste timber and thinned wood is difficult to burn due to its high moisture content, and the combustion efficiency in the boiler is not so good, so the upper limit of moisture content is specified depending on the boiler model etc. In many cases, a drying step such as sun drying is required in advance. For example, the moisture content of raw wood such as thinned wood immediately after logging is relatively high at about 55-60% and the calorific value is only about 1,300-1,600 kcal / kg. Although it is bad, if the moisture content can be reduced to about 40% through the drying step, the calorific value can be increased to about 2,400 kcal / kg. It becomes possible to make it.

  However, although the drying process in the sun drying depends on the weather, it takes a long time of about several weeks to several months, so it is necessary to secure a storage place for the wooden chips during that time. For example, it may be preferable to install an appropriate drying apparatus so that the drying process can be performed in a shorter period of time without being influenced as much as possible. As such a drying apparatus, Patent Document 1 (Japanese Patent Laid-Open No. 2012-251699) includes a kiln main body that is rotatably and tiltably supported, and a hot air duct is disposed at a lower end side discharge port of the kiln main body, A rotary dryer is described in which hot air obtained by burning heavy oil or the like with a burner for generating wind is led into the kiln main body by the hot air duct, and the wood chips charged in the kiln main body are heated and dried. ing.

JP 2012-251699 A

  However, in the above-mentioned conventional device, hot air generated by burning fossil fuel such as heavy oil in a burner is used as a heat source for heating and drying the wood chips, which is the original purpose of preventing global warming. From this point of view, it is considered that it is more preferable to use the same woody biomass as the wood chip instead of the fossil fuel for the fuel for drying the wood chip by heating and drying. It is done.

  Biomass power generation systems also have a method in which wood chips are pyrolyzed in a reducing atmosphere to generate flammable gas, and a gas engine is driven by the generated flammable gas to generate power. In some cases, a large amount of pyroligneous acid is generated as a by-product when the wood chips are pyrolyzed. Although most of this wood vinegar is water, it may be partly used for agriculture etc. due to its strong acidity, but most of it is disposed of as industrial waste for a fee. Actually, it would be preferable to reduce the amount of this wood vinegar liquid to be disposed of in some way because it can reduce power generation costs.

  In view of the above points, the present invention can heat and dry wood chips for biomass power generation with hot air obtained by burning woody biomass having a low environmental load as solid fuel instead of fossil fuel, and biomass power generation It is an object of the present invention to provide a wood chip drying device for biomass power generation and a drying method capable of reducing the amount of wood vinegar liquid disposed of in the waste.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, pruned branches and rooting materials generated with the maintenance of forests and parks, edge materials generated at construction sites, etc. We paid attention to the fact that many waste materials such as building waste generated at demolition sites were disposed of as waste. The waste materials are not uniform in size and properties, vary in calorific value, are easily mixed with impurities, and are not very suitable for use as a fuel for biomass power generation. It is thought that it can be used enough if it is only burned as a heat source for heat drying treatment of wood chip fuel. If so, low-quality woody biomass such as the above-mentioned waste materials that have been disposed of as waste will be used effectively. I think that it can be done, and also about the wood vinegar liquid that is generated in large quantities as a by-product with biomass power generation, since most of it is moisture, for example, it will be vaporized by spraying into the hot air generated by the combustion of the waste materials etc. In this way, the present inventors have considered that it is possible to reduce the amount of disposal without much cost, and have reached the present invention.

  That is, in the wood chip drying apparatus for biomass power generation according to claim 1 according to the present invention, solid fuel charging means, an auxiliary burner, and solid fuel in the kiln body are combusted by self-combustion at one end of the kiln body that is rotatably and tiltably supported. A combustion air supply fan for supplying the combustion air necessary to make a hot air generating furnace with a secondary combustion chamber at the other end, and a wood for biomass power generation at one end of a kiln body that is rotatably supported The chip insertion means is provided with a heating and drying furnace having a plurality of scraping blades on the inner peripheral wall, the hot air generating furnace and the heating and drying furnace are connected by a hot air supply duct, and the exhaust downstream of the heating and drying furnace The duct is provided with a dust collector, an exhaust fan, and a main damper for air volume adjustment. The hot air generating furnace has a static pressure sensor for detecting a static pressure in the kiln body, and a static pressure value detected by the static pressure sensor. Predetermined negative pressure value A static pressure / exhaust air volume controller that adjusts and controls the rotational speed of the exhaust fan or the opening of the main damper so as to maintain, and sprays the vinegar liquor produced by biomass power generation into the secondary combustion chamber It is characterized by comprising a pyroligneous acid spraying means for vaporizing.

  Moreover, in the wood chip drying apparatus for biomass power generation according to claim 2, the pyroligneous spraying means enters the secondary combustion chamber so that the hot air temperature derived from the secondary combustion chamber is maintained at a predetermined temperature value. It is characterized by having a pyroligneous acid spray amount controller for adjusting and controlling the quantity of pyroligneous acid sprayed.

  Further, in the wood chip drying method for biomass power generation according to claim 3, biomass power generation using a hot air generating furnace that generates hot air by burning and decomposing solid fuel as a main fuel, and hot air generated in the hot air generating furnace as a heat source. And a heating and drying furnace for heating and drying wood chips for heating, and in the hot-air generator, low-quality woody biomass that is unsuitable for biomass power generation is input as solid fuel, and the low-quality woody biomass is burned and decomposed The combustion air is supplied in an amount commensurate with the amount of combustion and decomposed, and the hot air generated by the combustion is sprayed with the pyroligneous acid produced by the biomass power generation to vaporize the hot air to the heating and drying furnace. On the other hand, in the heating and drying furnace, wood chips that can be used for biomass power generation are heated and dried with hot air introduced from the hot air generator. It is characterized in that.

  According to the wood chip drying apparatus for biomass power generation according to claim 1 of the present invention, the solid fuel charging means, the auxiliary burner, and the solid fuel in the kiln main body are combusted by self-combustion at one end of the kiln main body that is rotatably and tiltably supported. A combustion air supply fan for supplying the combustion air necessary to make a hot air generating furnace with a secondary combustion chamber at the other end, and a wood for biomass power generation at one end of a kiln body that is rotatably supported The chip insertion means is provided with a heating and drying furnace having a plurality of scraping blades on the inner peripheral wall, the hot air generating furnace and the heating and drying furnace are connected by a hot air supply duct, and the exhaust downstream of the heating and drying furnace The duct is provided with a dust collector, an exhaust fan, and a main damper for air volume adjustment. The hot air generating furnace has a static pressure sensor for detecting a static pressure in the kiln body, and a static pressure value detected by the static pressure sensor. Predetermined negative pressure value A static pressure / exhaust air volume controller that adjusts and controls the rotational speed of the exhaust fan or the opening of the main damper so as to hold, and sprays the vinegar liquor generated by biomass power generation into the secondary combustion chamber Because it is equipped with a means of spraying wood vinegar to vaporize it, in the hot air generator, it is for biomass power generation with hot air generated by burning solid fuel such as woody biomass by self-combustion while minimizing the amount of fossil fuel used The wood chip can be heat-dried, and the burden on the environment when the wood chip is heat-dried can be reduced. In addition, by adjusting and controlling the amount of exhaust air based on the static pressure value of the kiln body, it supplies the combustion air necessary for self-combustion of solid fuel while suppressing excessive intrusion of outside air into the kiln body. It is possible to supply to the downstream heating and drying furnace without reducing the temperature of the hot air obtained by combustion as much as possible while stably burning the solid fuel, and the calorific value of solid fuel such as woody biomass is wasted as much as possible It can be effectively used for the heat drying treatment of the wood chip for biomass power generation without making it. In addition, by spraying and vaporizing the pyroligneous acid produced as a by-product of biomass power generation on hot air generated by burning solid fuel such as woody biomass, the amount of pyroligneous acid waste disposal is reduced without much cost. This can be expected to reduce power generation costs.

  According to the wood chip drying apparatus for biomass power generation according to claim 2, secondary combustion is performed so that the hot air temperature derived from the secondary combustion chamber is maintained at a predetermined temperature value in the pyroligneous acid spraying means. A wood vinegar liquid spray amount controller that adjusts and controls the amount of wood vinegar sprayed indoors, so even if the calorific value fluctuates due to variations in the properties of solid fuel such as woody biomass, wood chips for biomass power generation Hot air having a desired temperature suitable for the heat drying process can be stably supplied. In addition, by generating hot air that is hotter than the temperature suitable for heat drying treatment of wood chips for biomass power generation in the hot air generator, more pyroligneous acid can be sprayed and vaporized. It becomes possible to reduce the amount of disposal more effectively.

  Moreover, according to the wood chip drying method for biomass power generation according to claim 3, a hot air generating furnace for generating hot air by burning and decomposing solid fuel as a main fuel, and hot air generated in the hot air generating furnace as a heat source. A heating and drying furnace that heats and drys wood chips for biomass power generation is also provided. In the hot air generator, low-quality woody biomass that is unsuitable for biomass power generation is input as solid fuel, and the low-quality woody biomass is burned. Supplying combustion air in an amount suitable for decomposition, combustion decomposition is performed, and hot air generated during combustion is sprayed with pyroligneous acid generated from biomass power generation to vaporize the hot air to the heating and drying furnace. On the other hand, in the heating and drying furnace, the wood chips that can be used for biomass power generation are heated and dried with hot air introduced from the hot air generating furnace. Therefore, in the heat drying process of wood chips, which are fuels for biomass power generation, the same wood biomass as wood chips can be used effectively as the main fuel for generating hot air while reducing the amount of fossil fuel used. It becomes possible to reduce the environmental load at the time of heat drying treatment. Moreover, as the woody biomass to be introduced into the hot air generating furnace, for example, low-quality woody biomass that is not suitable as a fuel for power generation of biomass such as unnecessary waste materials that have been disposed of in the past can be used effectively. By spraying and vaporizing pyroligneous acid produced as a by-product of biomass power generation against hot air generated by combustion of biomass, the amount of pyroligneous acid waste disposal can be reduced without much cost, reducing power generation costs Can be expected.

It is a schematic explanatory drawing which shows one Example of the wood chip drying apparatus for biomass power generation and drying method which concern on this invention. It is sectional drawing of the secondary combustion chamber of the hot-air generation furnace of FIG. It is a principal part expanded sectional view of the static pressure seal part of the heating-drying furnace of FIG.

  In the wood chip drying apparatus and drying method for biomass power generation according to the present invention, a hot air generating furnace for generating hot air by burning and decomposing solid fuel such as woody biomass as a main fuel, and generated in the hot air generating furnace A heating and drying furnace that heats and drys wood chips that are fuel for biomass power generation using the heated hot air as a heat source, and these hot air generation furnaces and the heating and drying furnace are connected by a hot air supply duct and are heated and dried. The exhaust duct downstream of the furnace is provided with a dust collector, an exhaust fan, a main damper for adjusting the air volume, and the like.

  The hot-air generating furnace rotatably supports a kiln main body having a heat-resistant caster around an inner wall surface, and a solid fuel charging means such as a charging chute and a screw feeder at one end of the kiln main body, and a solid fuel A small auxiliary burner that uses fossil fuels such as oil and natural gas, and combustion air necessary to burn the solid fuel injected into the kiln itself by self-combustion. A combustion air supply fan that has a secondary combustion chamber that burns and decomposes the scattered unburned fuel that flows down with the combustion exhaust gas of the solid fuel at the other end. One end of a hot air supply duct is connected to the upper part of the chamber.

  Further, a pyroligneous acid spraying means is provided for spraying the pyroligneous acid produced as a by-product along with the biomass power generation into the secondary combustion chamber for vaporization. The wood vinegar spray means includes a spray nozzle for spraying wood vinegar, a supply pump, a flow rate adjusting valve, and a wood vinegar spray amount controller for adjusting and controlling the amount of wood vinegar spray. In the pyroligneous acid spray amount controller, the hot air temperature derived from the downstream side of the secondary combustion chamber is controlled to be maintained at a predetermined temperature (for example, about 800 ° C.) based on the detected hot air temperature value. It is preferable that the amount of pyroligneous acid sprayed from the spray nozzle into the secondary combustion chamber can be adjusted and controlled. Even if the calorific value fluctuates greatly due to variations in the properties of solid fuel such as woody biomass (for example, moisture content, etc.), the woody vinegar spray can be controlled with respect to the downstream heating and drying furnace. This makes it possible to stably supply hot air at a temperature suitable for heat drying treatment of chips.

  The hot air generating furnace includes a static pressure sensor for detecting a static pressure at a corner of the kiln body on the auxiliary burner side, and a static pressure value detected by the static pressure sensor is a predetermined negative pressure value. For example, static pressure / exhaust for adjusting and controlling the rotational speed of the exhaust fan provided in the exhaust duct or the opening of the main damper so as to be maintained at the same level as the atmospheric pressure or slightly lower than the atmospheric pressure. It is equipped with an air volume controller, such as hot air generated in the kiln main body or steam generated in a large amount due to vaporization of the vinegar liquid sprayed in the secondary combustion chamber, etc. While preventing troubles, the outside air is prevented from entering the kiln body as much as possible so that the combustion air necessary for self-combustion of the solid fuel is supplied from the combustion air supply fan without excess or deficiency. .

  On the other hand, the heating and drying furnace rotatably supports a kiln main body having a plurality of scraping blades on the inner wall surface, and a wood chip for biomass power generation such as a charging chute or a screw feeder at one end of the kiln main body. The hot air supply duct is connected to the charging means, and the other end of the kiln main body is provided with a discharge gate for discharging the wood chips that have been subjected to the heat drying process, and is connected to the exhaust duct.

  In order to heat and dry the wood chip for biomass power generation using the apparatus configured as described above, first, the auxiliary burner of the hot air generating furnace is burned to preheat the inside of the kiln and then into the kiln body, for example, biomass power generation Low quality woody biomass such as waste materials that are not suitable for use is charged as solid fuel and ignited and combusted, and hot air generated at that time is introduced into the downstream secondary combustion chamber. In the secondary combustion chamber, the hot air introduced from the kiln main body is temporarily closed to prevent the hot air from flowing into the downstream heating and drying furnace, and then the solid fuel is combusted until the temperature setting value is reached. When the temperature in the secondary combustion chamber reaches a predetermined temperature while burning with the burner, the auxiliary burner is extinguished and preparation for supplying hot air is completed.

  When the preparation of hot air supply is completed, while supplying an appropriate amount of combustion air necessary for self-combustion of solid fuel from the combustion air supply fan, the vinegar solution is sprayed into the secondary combustion chamber to vaporize the hot air. After adjusting the temperature to the predetermined temperature, the hot air supply duct is opened to lead hot air from the secondary combustion chamber to the downstream heating and drying furnace, while the heating and drying furnace supplies wood chips for biomass power generation into the kiln body. To start. The wood chips supplied into the kiln main body are repeatedly scraped up by a plurality of scraping blades and flowed down while being dropped, while being exposed to high-temperature hot air supplied from a hot-air generating furnace and heated efficiently. It is dried and discharged and collected as biomass fuel that can be combusted efficiently in a power generation boiler.

  Thus, according to the wood chip drying apparatus for biomass power generation, solid fuel such as woody biomass can be used without using a burner that uses fossil fuel as much as possible except when solid fuel is ignited or preheated in the kiln. The wood chip for biomass power generation can be heat-dried by hot air generated by the self-combustion, and the environmental load associated with the heat-drying process of the wood chip can be reduced. In addition, because it is configured to minimize the entry of extraneous outside air into the hot air generation furnace and heating / drying furnace, the calorific value of solid fuel such as woody biomass, which has a lower calorific value than fossil fuels, is wasted as much as possible. It can be effectively used for the heat-drying treatment of the wood chip without doing so. In addition, even the same woody biomass is not suitable as a fuel for biomass power generation due to its properties and contamination, etc., and pruned branches and rooting materials, bark, scraps, and building waste materials that have been disposed of in the past. By using a relatively low-quality woody biomass such as a heat source for heat-drying wood chips for power generation, it can be effectively used without any trouble. In addition, a large amount of pyroligneous acid produced as a by-product with biomass power generation is sprayed and vaporized on hot air generated by the combustion of solid fuel such as woody biomass. It is possible to effectively reduce the amount of vinegar vinegar without increasing the cost, so that reduction in power generation cost can be expected.

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

  In the figure, reference numeral 1 denotes a wood chip drying apparatus for biomass power generation. A rotary kiln type hot air generator 2 that generates hot air by burning and decomposing solid fuel such as woody biomass as a main fuel, and a hot air generator 2 And a rotary kiln heating / drying furnace 3 for heating and drying wood chips, which are fuels for biomass power generation, using the generated hot air as a heat source. The hot air generating furnace 2 and the heating / drying furnace 3 are connected to a hot air supply duct 4. The hot air generated by the hot air generating furnace 2 is supplied to the heating and drying furnace 3. Further, an exhaust duct 5 for exhausting hot air after the heat drying treatment is connected to the heating and drying furnace 3, and a dry cyclone 6 that is a dust collector for capturing dust in the exhaust gas and a bug are disposed downstream of the exhaust duct 5. A filter 7 is provided, and a main damper 8 for adjusting the amount of exhaust air, an exhaust fan 9 and a chimney 10 are provided on the downstream side of the filter 7.

  The hot air generating furnace 2 includes a kiln main body 12 formed by surrounding a heat-resistant caster 11 such as a refractory brick or ceramic having no scraping function on an inner wall surface of a cylindrical steel plate. It is tilted and supported so that it can rotate freely. At one end thereof, it is used for charging chute 14 which is a solid fuel charging means, preheating and seed fire in the kiln main body 12, and fossil fuel such as oil and natural gas is used. A small auxiliary combustion burner 15 and a combustion air supply fan 16 for supplying combustion air necessary for burning solid fuel introduced into the kiln main body 12 by self-combustion are provided, while the other end portion is provided with solid fuel. Is provided with a secondary combustion chamber 17 that combusts and decomposes the flammable unburned matter that is generated when the is burned.

  In addition, a static pressure sensor 18 for detecting the static pressure in the kiln main body 12 is provided at the corner of the kiln main body 12 of the hot air generating furnace 2 on the auxiliary burner 15 side, and is detected by the static pressure sensor 18. A static pressure / exhaust air volume controller 19 for adjusting and controlling the opening degree of the main damper 8 provided in the exhaust duct 5 or the rotational speed of the exhaust fan 9 so that the static pressure value to be maintained is a predetermined static pressure value. The amount of exhaust air is controlled so that the static pressure in the kiln main body 12 is substantially the same as the atmospheric pressure or slightly negative, for example, about −10 to −30 Pa in terms of atmospheric pressure ratio. The hot air generated in the interior of the kiln main body 12 is prevented while spouting from both ends of the kiln main body 12 such as hot air generated in the interior of the kiln vinegar and a large amount of water vapor generated in the secondary combustion chamber 17 to be described later is prevented. To prevent intrusion of fresh outside air as much as possible In this way, only the combustion air necessary for self-combustion of the solid fuel is supplied without excess and deficiency, and the amount of heat generated by the solid fuel is wasted as much as possible while suppressing the decrease in hot air temperature due to the entry of outside air as much as possible. Without being able to supply to the downstream heating and drying furnace 3.

  Like the kiln main body 12, the secondary combustion chamber 17 has a heat-resistant caster 20 attached to its inner wall surface, and hot air introduced from the kiln main body 12 takes about 2 seconds or more downstream. The hot air supply duct 4 has a vertically long structure, and the spillable unburned matter such as fine carbides contained in the hot air generated by burning solid fuel such as woody biomass is heated to a high temperature. While passing through the maintained secondary combustion chamber 17, it is completely burned and decomposed. Reference numeral 21 in the figure denotes a small auxiliary burner that supplies hot air into the secondary combustion chamber 17 using fossil fuel, like the auxiliary combustion burner 15. The secondary combustion chamber 17 is preheated by burning at some time and the like is extinguished after completion of preheating.

  The secondary combustion chamber 17 is vaporized by spraying an appropriate amount of pyroligneous acid produced as a by-product accompanying biomass power generation with respect to the hot air in the combustion chamber. A wood vinegar solution spraying means 22 for adjusting the hot air temperature suitable for the heat drying treatment of the wood chip for biomass power generation in the furnace 3 is provided. A large amount of the wood vinegar is generated as a by-product with biomass power generation, and many of them are conventionally disposed of for a fee, but as described above, sprayed into the secondary combustion chamber 17 for adjusting the hot air temperature. By evaporating, the amount of pyroligneous acid waste disposal can be effectively reduced without much cost, thereby contributing to lower power generation costs.

  The pyroligneous acid spraying means 22 includes a pyroligneous acid storage tank 23 for storing pyroligneous acid liquid generated by biomass power generation, a spray nozzle 24 facing the inside of the secondary combustion chamber 17, and the spray nozzle 24 and the pyroligneous liquid. A supply pipe 25 connecting the storage tank 23, a supply pump 26 and a flow rate adjusting valve 27 provided in the middle of the supply pipe 25, a temperature sensor 28 provided in the middle of the hot air supply duct 4, and the spray nozzle 24 A wood vinegar liquid amount adjustment controller 29 that adjusts and controls the amount of wood vinegar liquid sprayed from, and a predetermined temperature set value is set and registered in advance in the wood vinegar liquid spray amount controller 29. The amount of pyroligneous acid sprayed into the secondary combustion chamber 17 is adjusted and controlled by adjusting the opening of the flow rate adjusting valve 27 according to the amount of difference between the detected temperature value of the hot air and the temperature setting value. Do it .

  For example, when the hot air temperature detected by the temperature sensor 28 is lower than a preset temperature setting value, the flow rate adjusting valve 27 is closed to reduce the hot air temperature to be sprayed. On the other hand, when the hot air temperature is higher than the temperature set value, the flow rate adjusting valve 27 is opened to increase the spray amount of the wood vinegar, and the properties of the solid fuel such as woody biomass (water content, etc.) Even when the calorific value fluctuates greatly due to variations, the hot air temperature led out from the secondary combustion chamber 17 is kept substantially constant. If the temperature set value is set to about 800 ° C., for example, the flammable unburned part generated during the combustion of the solid fuel can be reliably burned and decomposed in the secondary combustion chamber 17, and the wood chip Hot air suitable for heat drying treatment (for example, a higher hot air temperature can improve heat drying efficiency, but if it is too high, wood chips that are biomass fuel may be burned in the heat drying furnace 3). Can be supplied to the downstream heating and drying furnace 3.

  Further, the hot air temperature generated in the hot air generating furnace 2 is considerably higher than the set temperature value (for example, about 800 ° C.) suitable for the heat drying treatment of the wood chip for biomass power generation, for example, about 1,000. When the temperature is set to about ˜1,200 ° C., the amount of the pyroligneous spray sprayed for adjusting the hot air temperature can be increased by that amount, thereby further reducing the waste disposal amount of the pyroligneous acid.

  When solid fuel such as woody biomass is to be self-combusted stably, it is necessary to sufficiently supply combustion air (about 1.5 to 1.8 in air ratio) and maintain it in an oxidative combustion state. (If the combustion air is insufficient, a reduced combustion state occurs and a large amount of unburned residue is generated without burning the solid fuel.) The secondary combustion chamber 17 is provided with an oxygen concentration sensor 30, and the oxygen If the detected value of the concentration sensor 30 shows, for example, about 10% or less (in a reduction combustion state), the air amount adjustment damper 31 built in the combustion air supply fan 16 is forcibly opened automatically or manually. The combustion air amount supplied to the kiln main body 12 is increased to restore the oxidation combustion state.

  Further, as shown in FIG. 2, solid unburned components such as combustion ash and carbides of solid fuel such as woody biomass discharged from the kiln main body 12 are temporarily stored in the lower part of the secondary combustion chamber 17. The storage hopper 32 is provided with a discharge gate 33 for discharging combustion ash at the lower end of the storage hopper 32 so that the storage hopper 32 is filled with combustion ash to some extent. If this is the case, the discharge gate 33 is opened, and the discharge gate 33 is discharged to an appropriate transport vehicle or the like disposed under the discharge gate 33.

  In addition, a recombustion air supply means 34 for supplying recombustion air to the solid unburned portion is provided above the discharge gate 33 at the lower end of the storage hopper 32, and the recombustion air supply means is provided. 34 has an air supply pipe 35 having a predetermined diameter along the outer periphery of the storage hopper 32, for example, an approximately 100 mm inner diameter, which is provided substantially horizontally, and from the air supply pipe 35 toward the inside of the storage hopper 32. A large number of air injection holes 36 having a diameter of, for example, about 10 mm, which are penetrated by a large number, are formed at predetermined intervals around the entire circumference of the storage hopper 32, and air is blown from a blower 37 provided in the vicinity of the storage hopper 32. When the recombustion air is supplied into the air supply pipe 35, the recombustion air circulates along the outer periphery of the storage hopper 32, and is injected and supplied from the air injection holes 36 toward the inside of the hopper. West In addition, the solid unburned portion discharged into the storage hopper 32 without being combusted in the kiln main body 12 is sufficiently burnt and decomposed to generate hot air, and the calorific value of solid fuel such as woody biomass can be effectively utilized. I am doing so.

  In addition, as solid fuel thrown into the hot-air generating furnace 2, such as building waste materials in which impurities are expected to be mixed, pruned branches and rooting materials that are not uniform in size and properties, and vary in calorific value, etc. When relatively low-quality woody biomass is used, unburned residue such as solid unburnt or splattered unburned is likely to be generated, and some of the impurities may remain in it. Of these, the solid unburned portion can be burned and decomposed by the recombustion air supplied from the air supply pipe 35, while the scattered unburned portion is also a secondary combustion chamber in a high temperature atmosphere. 17 can be completely burned and decomposed while passing through the inside, there is no problem in terms of maintenance, and there is no risk of adversely affecting the quality of the wood chips used as fuel for the boiler for power generation. Can be adopted To become.

  Further, a hot air supply duct 4 that supplies high-temperature hot air generated by burning solid fuel to the downstream heating and drying furnace 3 as a heat source is connected near the upper portion of the secondary combustion chamber 17. In the vicinity of the base end portion of the supply duct 4, a hot air amount adjusting damper 38 is provided so that the amount of hot air supplied to the heating and drying furnace 3 can be adjusted, while the connecting portion of the hot air supply duct 4 to the heating and drying furnace 3 is provided. A temperature sensor 39 for detecting the temperature of hot air in the duct is provided in the vicinity, and an outside air introduction port 40 is provided on the upstream side of the temperature sensor 39, and the vicinity of the downstream of the duct detected by the temperature sensor 39 is provided. An appropriate amount of outside air is introduced from the outside air introduction port 40 in accordance with the hot air temperature so that the hot air temperature supplied to the heating and drying furnace 3 can be finely adjusted so as to be maintained at an appropriate temperature. An exhaust damper 41 is provided at the upper end of the secondary combustion chamber 17 so as to be freely opened and closed, and is released when the hot air amount adjusting damper 38 is closed or in an emergency, etc., to release the hot air in the secondary combustion chamber 17. It is possible.

  On the other hand, the heating and drying furnace 3 supports a kiln main body 43 formed by arranging a plurality of scraping blades 42 on the inner wall surface of a cylindrical steel plate so as to be rotatable on a base 44, and at one end thereof. Is connected to the hot air supply duct 4 via an inlet hood 45 and is provided with a screw feeder 46 which is a wood chip charging means for biomass power generation, while hot air is supplied to the other end via an outlet hood 47. The exhaust duct 5 for derivation is connected, and a lower end portion of the outlet hood portion 47 is provided with a discharge gate 48 for discharging the wood chips after the drying process, and a belt conveyor 49 is provided below the discharge gate 48. The arranged and dried wood chips for biomass power generation are transported to a chip storage silo or the like.

  In addition, the fitting portion between the inlet hood portion 45 and the outlet hood portion 47 and the kiln main body 43 employs a seal structure so as to suppress the intrusion of outside air, for example, on the inlet hood portion 45 side. The structure will be described as an example. As shown in FIG. 3, an annular sealing material fixing piece 50 is projected along the outer peripheral surface of the kiln main body 43 on the distal end side of the inlet hood portion 45, and the sealing material For example, a base end portion of a metal seal plate 51 is fixed to the distal end portion of the fixed piece 50 as a sealing material for preventing the entry of outside air, and the free end portion of the seal plate 51 is used as the outer peripheral surface of the kiln main body 43. The gap between the outer peripheral surface of the kiln main body 43 and the inlet hood portion 45 is sealed to prevent the outside air from entering the kiln without disturbing the rotation of the kiln main body 43. Have .

  Further, the flow velocity of the outside air A that is about to enter the substantially closed gap space 52 formed by the outer peripheral surface of the kiln main body 43, the sealing material fixing piece 50 protruding from the inlet hood portion 45, and the seal plate 51. Are arranged in a zigzag manner to form a labyrinth structure, and air A ′ that has entered the gap space 52 is sucked and exhausted with a predetermined suction force. Exhaust means 57 including an exhaust duct 54, a suction fan 55, and an air volume adjustment damper 56 for adjusting the suction amount is provided.

  The inlet hood portion 45 is provided with a static pressure sensor 59 for detecting the static pressure in the kiln main body 43, while the static pressure sensor 58 for detecting the static pressure in the gap space 52 is provided. The static pressure values detected by the static pressure sensors 58 and 59 are taken into the static pressure seal controller 60, and the static pressure seal controller 60 opens the air volume adjusting damper 56 according to the difference value between the static pressure values. The suction force is adjusted by appropriately adjusting the degree. At this time, the suction force is controlled so that the static pressure value in the gap space 52 and the static pressure value in the kiln main body 43 are maintained at approximately the same level, and the air A ′ that has entered the gap space 52 is removed. While forcibly exhausting, the hot air in the kiln main body 43 is not exhausted as much as possible, so that the hot air in the kiln can be effectively used for drying wood chips for biomass power generation without waste. The sealing structure and exhaust means between the outlet hood portion 47 and the kiln main body 43 are also substantially the same as the inlet hood portion 45, and the description thereof will be omitted.

  Reference numeral 61 in the figure denotes slaked lime supply means 61 for neutralizing acetic acid in the exhaust gas generated by spraying the pyroligneous acid liquid onto the hot air in the pyroligneous acid spraying means 22, and the slaked lime supply means 61 is slaked lime. The storage bottle 62, a screw feeder 63 for cutting out slaked lime, and a blower (not shown) for blowing slaked lime cut out from the screw feeder 63 into the exhaust duct 5 are arranged in accordance with the acetic acid concentration in the exhaust gas. An appropriate amount of slaked lime that can be summed is blown into the exhaust duct 5, neutralized in the bag filter 7 downstream, and collected.

  Then, using the wood chip drying apparatus 1 for biomass power generation having the above-described configuration, for example, relatively low-quality wood biomass such as unnecessary waste is burned as a solid fuel, and the generated hot air is used as a heat source to heat the wood chip for biomass power generation. When performing the drying process, first, the temperature of the wood vinegar liquid spraying means 29 of the wood vinegar liquid spraying means 22 is completely set to the temperature setting value of the wood vinegar liquid spraying means 29. For example, 800 ° C. suitable for the drying process is set and registered, and the hot air amount adjusting damper 38 of the hot air supply duct 4 downstream of the hot air generating furnace 2 is closed, while the exhaust damper 41 at the upper end of the secondary combustion chamber 17 is opened. In this state, the auxiliary burner 15 provided in the kiln main body 12 and the auxiliary burner 21 provided in the secondary combustion chamber 17 are burned together, and the kiln main body 12 and the secondary burner After preheating the interior of the firing chamber 17, the solid fuel is supplied into the kiln main body 12 from the input chute 14, and an air amount corresponding to the input amount of the solid fuel is supplied from the combustion air supply fan 16 into the kiln. I will do it.

  The solid fuel charged into the kiln main body 12 is easily ignited by being exposed to hot air from the auxiliary burner 15 and downstream of the kiln while being stably combusted by the combustion air supplied from the combustion air supply fan 16. The hot air generated by the combustion of the solid fuel is introduced into the secondary combustion chamber 17 downstream of the kiln body 12 as it flows down to the side. When the hot air temperature in the secondary combustion chamber 17 reaches about the above temperature set value, the auxiliary combustion burner 15 and the auxiliary burner 21 are extinguished, while the solid fuel is self-combusted only by supplying combustion air, 3 completes preparation for supplying hot air to 3.

  When the preparation of hot air supply is completed, the exhaust damper 41 is closed, while the hot air amount adjusting damper 38 is opened, and hot air is led from the secondary combustion chamber 17 to the downstream heating and drying furnace 3 through the hot air supply duct 4. At this time, in the hot air generating furnace 2, the static pressure / exhaust air flow controller 19 maintains the static pressure in the furnace at the same level as the atmospheric pressure or slightly lower than the atmospheric pressure. Intrusion of extraneous outside air, which causes a decrease, is suppressed as much as possible, and can be supplied to the downstream heating / drying furnace 3 without reducing the temperature of the hot air obtained by burning the solid fuel as much as possible.

  Further, if the properties (water content, etc.) of the solid fuel vary, the hot air temperature also fluctuates. However, the wood vinegar spray amount control of the wood vinegar spray means 22 which is the hot air temperature adjusting means provided in the secondary combustion chamber 17 is controlled. In the vessel 29, the vinegar according to the amount of difference between the detected value of the hot air temperature detected by the temperature sensor 28 provided in the hot air supply duct 4 downstream of the secondary combustion chamber 17 and the temperature set value set and registered in advance. The degree of opening of the flow rate adjusting valve 27 of the liquid spraying means 22 is adjusted and controlled. For example, when the hot air temperature is lower than the temperature set value, the spray amount of the wood vinegar liquid from the spray nozzle 24 into the secondary combustion chamber 17 is reduced. In addition, when the hot air temperature is higher than the temperature set value, it is adjusted to increase the spray amount of the pyroligneous acid solution, and the hot air temperature is supplied while being adjusted to a predetermined temperature.

  At this time, water vapor is generated with the spraying of the wood vinegar as described above, and a large amount of water vapor that inhibits heat drying is mixed in the hot air, but in the static pressure / exhaust air volume controller 19 Since the amount of exhaust air is controlled so that the static pressure in the furnace is maintained at a negative pressure, the wood chips in the downstream heating and drying furnace 3 are quickly exhausted while preventing the blowout from the gaps at both ends of the kiln main body 12. The influence on the heat drying process can be suppressed.

  In addition, when burning relatively low-quality woody biomass such as waste material as solid fuel (self-combustion), for example, because the calorific value is low and the combustion rate is slow compared to solid fuel such as RPF, Although it is necessary to make the residence time of the fuel in the kiln relatively long (for example, about 45 minutes) by suppressing the rotation speed of the kiln body 12, it is still difficult to completely burn and decompose in the kiln. A large amount of unburned residues such as carbides are generated, and scatterable unburned parts flow down with hot air, and solid unburned parts are discharged together with combustion ash.

  Among these, the spillable unburned matter is recombusted and completely burned and decomposed while passing through the secondary combustion chamber 17 maintained at about 800 ° C., while being stored in the storage hopper 32 together with the combustion ash. The discharged solid unburned portion is re-injected and supplied at a predetermined pressure (for example, about 1.0 to 2.0 kPa) uniformly from the plurality of air injection holes 36 provided around the storage hopper 32. By the combustion air, it is blown up to swirl inside the storage hopper 32 and vigorously stirred and fluidized, and is suitably combusted and decomposed as hot air without causing a local high temperature region that causes clinker generation. Derived.

  On the other hand, in the heating and drying furnace 3 to which hot air is supplied, the wood chip for biomass power generation put into the kiln main body 43 by the screw feeder 46 is repeatedly scraped up by the scraping blades 42 provided around the inner wall surface and dropped into the kiln. The inside of the main body 43 is allowed to flow down, while being exposed to the hot air in the meantime, it is efficiently heated and dried, and the wood chips that have been dried are sequentially discharged from the discharge gate 48 below the outlet hood 47 and collected. .

  At this time, the static pressure in the kiln main body 43 of the heating and drying furnace 3 is maintained at about -70 to -90 Pa at an atmospheric pressure ratio lower than that of the hot air generating furnace 2, and in the static pressure seal controller 60, The opening degree of the air volume adjusting damper 56 of the exhaust duct 54 connected to the clearance 52 between the outer peripheral surface of the kiln main body 43, the hood portions 45 and 47 of the inlet and outlet hoods 45 and 47, and the seal plate 51 is adjusted. Then, the static pressure value in the gap space 52 is controlled to be maintained at substantially the same level as the static pressure value in the kiln main body 43, and the outside air A that attempts to enter the kiln inside from the gap space 52 is controlled. The labyrinth structure forcibly exhausts air from the exhaust duct 54 while suppressing the flow rate, thereby preventing intrusion, and hot air supplied from the hot air supply duct 4 into the kiln main body 43 from the gap space 52. To have been prevented from being forcibly exhausted, it is available in the drying process of biomass for power generation wood chips without as much as possible waste hot air obtained by burning solid fuel.

  In this way, when wood chips that are fuel for biomass power generation are heat-dried, solid fuel such as woody biomass, which is the same as wood chips, is effectively used as the main fuel for generating hot air while reducing the amount of fossil fuel used. It can be used and the load on the environment can be reduced. In addition, as a fuel for generating hot air, for example, relatively low-quality woody biomass such as pruned branches and rooting materials, bark, scraps, and building waste materials that have been disposed of in the past can be used. Can be effectively used. In addition, a large amount of pyroligneous acid produced as a by-product of biomass power generation is sprayed and vaporized on hot air generated by the combustion of solid fuel such as woody biomass. The liquid can be reduced without much cost, which is preferable.

  As the solid fuel to be introduced into the hot-air generating furnace 2, it is preferable to employ woody biomass such as waste material as in the above-mentioned embodiment for the purpose of reducing the environmental load. However, the present invention is not limited to this, and solid fuels such as RPF and RDF can also be effectively employed.

DESCRIPTION OF SYMBOLS 1 ... Wood chip dryer for biomass power generation 2 ... Hot-air generator 3 ... Heating-drying furnace 4 ... Hot-air supply duct 5 ... Exhaust duct 6 ... Dry cyclone (dust collector) 7 ... Bag filter (dust collector)
8 ... Main damper 9 ... Ventilator 12, 43 ... kiln body
DESCRIPTION OF SYMBOLS 14 ... Input chute (solid fuel injection means) 15 ... Auxiliary burner 16 ... Combustion air supply fan 17 ... Secondary combustion chamber 18 ... Static pressure sensor 19 ... Static pressure / exhaust air volume controller 22 ... Wood vinegar liquid spray means 23 ... Wood vinegar Liquid storage tank 24 ... Spray nozzle 27 ... Flow rate adjusting valve 28 ... Temperature sensor 29 ... Pyrotechnic liquid spray amount controller 42 ... Scrape blade 46 ... Screw feeder (wood chip feeding means for biomass power generation)
61. Slaked lime supply means

Claims (3)

  A combustion air supply fan for supplying combustion air necessary for burning the solid fuel in the kiln main body by self-combustion at one end of the kiln main body, which is tiltably supported so as to be combusted, is connected to the other end. A hot-air generating furnace with a secondary combustion chamber in the part, a wood chip charging means for biomass power generation at one end of a kiln main body that is rotatably and tiltably supported, and a heating and drying furnace in which a plurality of scraping blades are provided around the inner peripheral wall The hot air generating furnace and the heating and drying furnace are connected by a hot air supply duct, and the exhaust duct downstream of the heating and drying furnace includes a dust collector, an exhaust fan, and a main damper for adjusting the air volume, and generating the hot air The furnace includes a static pressure sensor for detecting the static pressure in the kiln body, and the rotational speed of the exhaust fan or the main damper so that the static pressure value detected by the static pressure sensor maintains a predetermined negative pressure value. Adjust and control the opening A power generation unit for biomass power generation, comprising a static pressure / exhaust air flow rate controller, and further comprising a pyroligneous acid spraying means for spraying and vaporizing the pyroligneous acid produced with biomass power generation toward the secondary combustion chamber. Wood chip drying equipment.   2. The wood chip drying apparatus for biomass power generation according to claim 1, wherein the pyroligneous acid spraying means sprays the hot air temperature derived from the secondary combustion chamber into the secondary combustion chamber so as to maintain a predetermined temperature value. A wood chip drying device for biomass power generation, comprising a wood vinegar spray amount controller for adjusting and controlling the amount of wood vinegar.   A hot air generating furnace that generates hot air by burning and decomposing solid fuel as a main fuel, and a heating and drying furnace that heats and drys wood chips for biomass power generation using the hot air generated in the hot air generating furnace as a heat source, In the hot-air generator, low-quality woody biomass that is unsuitable for biomass power generation is introduced as a solid fuel, and combustion air is supplied in an amount commensurate with the low-quality woody biomass for combustion and decomposition. The hot air generated by the combustion is sprayed with the pyroligneous acid produced by the biomass power generation and vaporized, and the hot air is led to the heating and drying furnace, while in the heating and drying furnace, the hot air introduced from the hot air generating furnace A wood chip drying method for biomass power generation, wherein a wood chip that can be used for biomass power generation is heated and dried.

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