JP2018087310A - Carbonizing apparatus and method for carbonization of woody biomass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbonizing apparatus and a carbonizing method for woody biomass capable of efficiently carbonizing woody biomass. SOLUTION: An indirect heating type carbonization furnace 2, a hot air generation furnace 3 for burning and decomposing wood gas, and a hot air supply duct 5 for supplying hot air generated in the hot air generation furnace to an outer cylinder 22 of the carbonization furnace 2. With. Further, the hot air supply duct 5 is branched halfway, one branch duct 5a is connected to the biomass supply side end of the carbonization furnace outer cylinder 22, and the other branch duct 5b is connected to the discharge side end. Each of the branch ducts 5a and 5b is provided with dampers 33 and 34 for opening and closing the flow path. Then, the dampers 33 and 34 are controlled to open and close based on the temperature of the inner cylinder on the biomass supply side of the carbonization furnace 2 so that the flow of hot air is switched between the cocurrent flow direction and the counterflow direction with respect to the biomass flow direction. [Selection] Figure 1

Description

  The present invention relates to a carbonization treatment apparatus and a carbonization treatment method for woody biomass in which woody biomass is carbonized by an indirect heating type rotary kiln.

  In recent years, for the purpose of global warming prevention, effective use of resources, etc., woody biomass such as waste timber and thinned wood that has been conventionally cut out from forests and disposed of as waste is chipped, A biomass power generation system in which this is burned in a boiler as a biomass fuel and a steam turbine is rotated with high-pressure steam generated thereby has attracted attention. On the other hand, even if it is the same woody biomass, it occurs with the maintenance of forests and parks, for example, pruned branches and rooting materials, which are also called difficult-to-use materials, bark, and edge materials generated at construction sites, Or, building waste materials generated at the site of building demolition, etc. are not uniform in size and properties, vary in calorific value, and impurities are likely to be mixed in, so it is not easy to use as biomass fuel. The situation is that many of them are still not suitable and are disposed of as industrial waste for a fee.

  In addition, instead of burning such woody biomass such as difficult-to-use materials as it is, if carbonization treatment is performed using, for example, a carbonization furnace, it can be adjusted to a constant calorific value and can be burned stably. In addition, it is considered that it can be recovered as charcoal fuel that can be used as fuel for burners and the like by further pulverizing it.

  As shown in Patent Document 1 (Japanese Patent Application No. 2006-47208), the applicant of the present invention is a rotary kiln of an indirect heating system having a double cylinder structure including an inner cylinder that is rotatably supported to be inclined and an outer cylinder that covers the inner cylinder. The carbonaceous biomass is carbonized in a carbonization furnace that employs, and the wood gas generated by the carbonization process is introduced into the hot air generating furnace for combustion decomposition, and the hot air generated at that time is generated in the outer cylinder of the carbonizing furnace. An application has been filed for a self-supporting combustion type woody biomass carbonization apparatus which is supplied to the inside of the space between the outer cylinder and the inner cylinder for effective use.

  The carbonization apparatus employs a cocurrent heating system in which hot air is flowed in parallel with the downflow direction of the woody biomass supplied into the kiln and heated. In this co-current heating method, since the high temperature hot air generated in the hot air generating furnace is first introduced into the kiln supply side, the atmospheric temperature in the inner cylinder on the kiln supply side can be maintained at a high temperature. Therefore, even if woody biomass with a high water content is supplied, the inner cylinder temperature on the kiln supply side, such as bark, can be maintained even at about 300 ° C. or higher, which is the tree gas generation temperature. It can be evaporated sufficiently. As a result, it is possible to prevent the problem of biomass growth on the inner wall surface of the inner cylinder on the kiln supply side caused by insufficient deficiency of moisture.

Japanese Patent Application No.16-47208

  However, the carbonization furnace employs an indirect heating and cocurrent heating type rotary kiln, which is difficult in terms of heating efficiency. In general, the co-current heating method has a higher exhaust gas temperature than the heating material discharged from the kiln, while the countercurrent heating method in which hot air flows in the opposite direction to the material flow direction is more than the discharged heating material. The exhaust gas temperature can be lowered, and the countercurrent heating method is better for heating efficiency. In addition, the carbonization furnace has to adopt an indirect heating method in which heating efficiency is inferior to that of the direct heating method, but self-sustained combustion using hot air generated by burning and decomposing wood gas generated by carbonization treatment. Since it is a type | mold, what can save fossil fuels, such as heavy oil, as much as possible by improving heating efficiency is desired.

  This invention makes it a subject to provide the carbonization processing apparatus and carbonization processing method of the wood type biomass which can carbonize wood type biomass efficiently in view of said point.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, have successfully developed a cocurrent heating method that can quickly increase the inner cylinder temperature on the woody biomass supply side and a countercurrent method that is excellent in heating efficiency. It is considered that the advantages of both heating systems can be utilized in combination, and the present invention has been achieved.

  That is, in the carbonization apparatus for woody biomass according to claim 1 according to the present invention, a carbonization furnace for carbonizing woody biomass with an indirect heating type rotary kiln, and wood gas generated in association with the carbonization treatment of the carbonization furnace And a hot air supply duct for supplying hot air generated in the hot air generator to the outer cylinder of the carbonization furnace, and the hot air supply duct is branched in the middle, and one of the branches The duct is connected to the biomass supply side end of the carbonization furnace outer cylinder, while the other branch duct is connected to the discharge side end, and each branch duct is provided with a damper for opening and closing the flow path so as to be opened and closed. Based on the temperature of the inner cylinder on the biomass supply side of the furnace, the dampers are manually or automatically controlled to switch the flow of hot air to the flow direction of the biomass in the carbonization furnace in the cocurrent or countercurrent direction. It is characterized by comprising a driving controller that.

  Moreover, the carbonization apparatus for woody biomass according to claim 2 is characterized by comprising hot air temperature adjusting means for maintaining the hot air temperature downstream of the hot air generator at a predetermined temperature.

Further, in the woody biomass carbonization apparatus according to claim 3, the hot air temperature adjusting means includes the wood gas derived from the carbonization furnace and the outside air supplied from the outside air supply fan, and is included in the wood gas. Air-cooling heat exchanger that condenses and collects a part of the high-boiling tar components that are generated, and tar combustion that adjusts and controls the amount of tar combustion in the hot-air generator by adjusting the amount of outside air supplied by the outside air supply fan It is characterized by comprising a quantity controller.

  Further, in the method for carbonizing woody biomass according to claim 4, the carbonization furnace is heated by setting the flow of hot air generated in the hot air generator at the start of operation as a parallel flow direction to the flow direction of biomass in the carbonization furnace. When the inner cylinder temperature on the biomass supply side of the carbonization furnace is equal to or higher than a predetermined temperature, the flow of hot air generated in the hot air generator is switched to a counter-current direction with respect to the biomass flow direction, and then the biomass Is supplied into a carbonization furnace and carbonized.

  According to the carbonization treatment apparatus for woody biomass according to claim 1 of the present invention, an indirect heating type carbonization furnace for carbonizing woody biomass and combustion of wood gas generated in association with the carbonization treatment of the carbonization furnace A hot air generating furnace to be decomposed, and a hot air supply duct for supplying hot air generated in the hot air generating furnace to the outer cylinder of the carbonization furnace, branching the hot air supply duct in the middle, One end of the carbonization furnace is connected to the biomass supply side end, and the other branch duct is connected to the discharge end, and each branch duct is provided with a damper for opening and closing a flow path, Since the operation controller for switching the flow of the hot air to the flow direction of the biomass in the carbonization furnace in the parallel flow direction or the counter flow direction is provided based on the opening and closing of each damper based on the inner cylinder temperature on the biomass supply side, For example, At the start of rolling, etc., the inner cylinder temperature on the biomass supply side can be quickly increased to a temperature at which adhesion does not easily occur by flowing hot air in the cocurrent direction, and if the inner cylinder temperature becomes sufficiently high, the counterflow direction is switched. The biomass can be carbonized efficiently by using the co-current heating method and the counter-current heating method appropriately and flexibly.

  In addition, according to the woody biomass carbonization apparatus according to claim 2, since the hot air temperature adjusting means for maintaining the hot air temperature downstream of the hot air generating furnace at a predetermined temperature is provided, for example, the amount of wood gas generated in the carbonizing furnace Even if variations occur, the biomass in the furnace can be carbonized at a substantially constant temperature, and the carbide having the desired properties can be stably recovered.

  Moreover, according to the carbonization apparatus for woody biomass according to claim 3, the hot air temperature adjusting means exchanges heat between the wood gas led out from the carbonization furnace and the outside air supplied from the outside air supply fan. An air-cooled heat exchanger that condenses and separates part of the tar components contained in the air, and a tar combustion amount that adjusts and controls the amount of tar combustion in the hot-air generator by adjusting the outside air supply amount of the outside air supply fan Because it consists of a controller, it can separate and recover the excess tar component from the wood gas generated by the carbonization of woody biomass, and the hot air obtained by combustion decomposition of the wood gas containing the remaining tar component Is supplied to the carbonization furnace, so that the biomass in the furnace can be carbonized at a substantially constant temperature, and the carbide having the desired properties can be stably recovered.

  Further, according to the method for carbonizing woody biomass according to claim 4, when the operation is started, the flow of hot air generated in the hot air generator is set to be parallel to the flow direction of the biomass in the carbonization furnace. After heating, if the inner cylinder temperature on the biomass supply side of the carbonization furnace is equal to or higher than a predetermined temperature, the flow of hot air generated in the hot air generation furnace is switched so as to be in the countercurrent direction with respect to the biomass flow direction. Since the biomass is supplied into the carbonization furnace and carbonized, the inner cylinder temperature on the biomass supply side can be quickly raised to a temperature at which the biomass supply side hardly adheres by hot air flowing in the parallel flow direction at the start of operation, and the inner cylinder temperature is sufficiently high. If it increases and becomes a steady operation, biomass can be carbonized efficiently by hot air switched in the countercurrent direction.

It is a schematic explanatory drawing which shows one Example of the carbonization processing apparatus and carbonization processing method of the woody biomass which concerns on this invention.

  In the carbonization processing apparatus and the carbonization processing method for woody biomass according to the present invention, the woody system having an indirect heating type rotary kiln structure comprising an inner cylinder that is rotatably supported to be inclined and an outer cylinder that covers the inner cylinder. A carbonization furnace for biomass carbonization, a hot air generating furnace for generating hot air by burning and decomposing combustible wood gas generated by carbonization of the carbonization furnace by self-combustion, and hot air generated in the hot air generating furnace Is provided with a hot air supply duct for supplying the air to the outer cylinder of the carbonization furnace.

  Further, the hot air supply duct is branched in the middle, and one of the branch ducts is connected to the biomass supply side end of the carbonization furnace outer cylinder, while the other branch duct is connected to the discharge side end. In the middle of each, a damper for opening and closing the flow path is provided to be freely opened and closed. Further, each damper is manually or automatically controlled to open and close based on the temperature of the inner cylinder on the biomass supply side of the carbonization furnace, and the flow of hot air in the outer cylinder of the carbonization furnace is made to flow downward in the biomass in the inner cylinder of the carbonization furnace. On the other hand, an operation controller that switches to a cocurrent flow direction or a counterflow direction is provided.

  In the operation controller, for example, a predetermined temperature at which woody biomass having a high water content such as bark hardly adheres to the inner wall surface of the inner cylinder, for example, about 300 ° C., which is a tree gas generation temperature such as bark, is previously set. If the inner cylinder temperature on the biomass supply side of the carbonization furnace is lower than the set temperature, the biomass supply side is preheat-treated while the flow of hot air in the outer cylinder is set as a parallel flow direction, while the biomass supply If the inner cylinder temperature on the side becomes equal to or higher than the set temperature, the flow of hot air in the outer cylinder is switched manually or automatically in the counterflow direction to control the operation with priority on heating efficiency.

  Preferably, the apparatus further comprises hot air temperature adjusting means for maintaining the hot air temperature downstream of the hot air generating furnace at a predetermined temperature (for example, a predetermined temperature range suitable for carbonizing a desired quality carbide in the carbonization furnace). Even if there is some variation in the amount of wood gas generated in the carbonization furnace, the temperature of the hot air generated in the hot air generation furnace can be kept constant, and the desired properties of carbide can be recovered stably. As the hot air temperature adjusting means, for example, when the hot air temperature is lower than the predetermined temperature, the auxiliary burner provided in the hot air generating furnace is temporarily burned, or when the hot air temperature is equal to or higher than the predetermined temperature. Various means such as introducing an appropriate amount of outside air can be adopted.

  Preferably, as the hot air temperature adjusting means, the wood gas derived from the carbonization furnace and the outside air supplied from the outside air supply fan are heat-exchanged between the carbonization furnace and the hot air generation furnace, and included in the wood gas. An air-cooled heat exchanger that condenses and collects a portion of the high-boiling tar component that is separated, and adjusts the outside air supply amount of the outside air supply fan according to the hot air temperature downstream of the hot air generating furnace. You may provide the tar combustion amount controller which adjusts and controls the tar combustion amount in a generating furnace. In that case, the heat energy obtained by burning and decomposing the tar component in the wood gas generated by the carbonization treatment can be kept constant without wasting the heat energy as much as possible. If the warm air supplied to the cold heat exchanger is supplied as combustion air to the hot air generating furnace, the heating efficiency in the hot air generating furnace can be expected to be increased.

  In the carbonization apparatus for woody biomass having the above-described structure, for example, when carbonization suitable for charcoal fuel for burners is performed from woody biomass such as bark having a high water content, first, the biomass is subjected to a certain amount of tar. A heating temperature suitable for carbonization with the components remaining (for example, about 400 to 500 ° C.), and a hot air temperature in the outer cylinder suitable for indirectly heating the biomass in the inner cylinder to the heating temperature ( For example, about 900 to 1000 ° C.) is obtained in advance by experiments or the like, and the hot air temperature or the like is set and registered in the tar combustion amount controller. Further, as a temperature capable of suppressing the adhesion of the biomass, for example, about 300 ° C., which is a temperature at which wood gas is generated from the bark, is set and registered in the operation controller.

  Next, the damper of each branch duct is controlled to open and close by the operation controller, and the flow direction of the hot air in the outer cylinder is made parallel to the flow direction of the woody biomass in the inner cylinder of the carbonization furnace, The auxiliary burner of the generator is burned and hot air is supplied to the carbonization furnace for pre-heat treatment. At this time, by flowing the hot air from the hot air generating furnace in the parallel flow direction, the temperature of the carbonization furnace inner cylinder on the biomass supply side where adhesion easily occurs can be quickly increased.

  When the inner cylinder temperature is higher than the preset temperature registered in advance in the operation controller, the damper of each branch duct is controlled to be opened or closed manually or automatically by the operation controller. After switching the flow direction of the hot air to the countercurrent direction, biomass is supplied into the carbonization furnace in a predetermined amount and heated indirectly in a reducing atmosphere for carbonization. At this time, carbonization can be efficiently performed by flowing hot air from the hot air generating furnace in a countercurrent direction with respect to the biomass flowing down in the furnace.

  When the operation becomes stable, the auxiliary burner is extinguished and the operation shifts to the self-sustained combustion operation. At this time, if the hot air temperature downstream of the hot air generating furnace falls below the preset temperature range set and registered in advance, the hot air temperature is adjusted, for example, the auxiliary burner is temporarily burned, while the hot air temperature is set to the preset temperature. If the temperature exceeds the range, the hot air temperature is maintained within the set temperature range by introducing an appropriate amount of outside air, for example.

  In addition, for example, when an air-cooled heat exchanger and a tar combustion amount controller are used as the hot air temperature adjusting means, if the hot air temperature falls below the set temperature range, the amount of outside air supplied from the outside air supply fan is reduced and the hot air generating furnace On the other hand, if the hot air temperature is equal to or higher than the set temperature range, the hot air temperature is kept within the set temperature range by increasing the supply amount of outside air and reducing the amount of tar combustion in the hot air generating furnace.

  Thus, according to the carbonization treatment apparatus for woody biomass, the inner cylinder temperature on the biomass supply side can be quickly increased by a cocurrent heating method at the start of operation where the inner cylinder temperature is low. Even woody biomass with a high water content can be effectively suppressed from adhering to the inner wall surface of the inner cylinder, and if the inner cylinder temperature becomes sufficiently high, it can be switched to the countercurrent heating method manually or automatically. Biomass can be efficiently carbonized by using properly.

  Also, if the hot air temperature adjusting means maintains the hot air temperature downstream of the hot air generating furnace within a predetermined temperature range, even if there is some variation in the amount of wood gas generated in the carbonizing furnace, the hot air at a constant temperature is supplied to the carbonizing furnace. For example, it is possible to recover a carbide having desired properties suitable for, for example, a charcoal fuel for a burner.

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

  In the figure, 1 is a carbonizing apparatus for woody biomass, for example, a carbonizing furnace 2 that indirectly heats woody biomass such as pruned branches, rooting materials, and bark, which are also referred to as difficult-to-use materials, under a reducing atmosphere, and carbonizes them. And a hot air generating furnace 3 for generating hot air by burning and decomposing wood gas containing combustible tar components generated by the carbonization treatment in the carbonizing furnace 2 by self-combustion, and these carbonizing furnace 2 and hot air The generator gas 3 is connected to a wood gas outlet duct 4 and a hot air supply duct 5 to supply the wood gas generated in the carbonization furnace 2 to the hot air generator 3 via the wood gas outlet duct 4, while generating the hot air. The hot air generated in the furnace 3 is configured to be supplied to the carbonization furnace 2 through the hot air supply duct 5. Further, the carbonization furnace 2 is provided with an exhaust duct 6 for exhausting hot air, and a main damper 7 is opened and closed in the middle of the exhaust duct 6 and a main fan 8 is provided downstream thereof.

  The carbonization furnace 2 rotatably supports an inner cylinder 10 in which a plurality of scraping blades 9 are provided around an inner wall surface of a cylindrical steel plate, and has a woody biomass via a partition wall 11 at one end thereof. A supply hopper 12 for supply and a screw conveyor 13 are provided, and a discharge hopper 14 for discharging carbide generated by carbonizing woody biomass is provided at the other end.

  In the middle of the discharge chute 15 at the bottom of the discharge hopper 14, an open / close damper 16 is provided in two stages, and a screw conveyor 17 for discharging carbide is connected to the lower end of the discharge chute 15. When discharging the carbides delivered to the inside of the screw conveyor 14, the opening / closing dampers 16 are sequentially opened and closed, and the opening / closing dampers 16 are always discharged while being kept closed, and the inside of the screw conveyor 17 is being discharged. By constantly filling with carbide, the entry of outside air (oxygen) into the inner cylinder 10 from the outlet 18 at the end of the conveyor is blocked as much as possible, and the inside of the inner cylinder 10 is maintained in a reducing atmosphere suitable for carbonization. I try to be as possible.

  Further, a water jet nozzle 19 is provided in the middle of the screw conveyor 17, and cooling water in a water storage tank 20 installed in the vicinity is supplied to the water jet nozzle 19 through a water supply pipe 21, A predetermined amount of cooling water is sprayed onto the high-temperature carbides flowing down in order to wet and cool appropriately, thereby preventing problems such as scattering of the discharged carbides and spontaneous ignition.

  In the figure, reference numeral 22 denotes an outer cylinder through which hot air for indirectly heating the woody biomass supplied into the inner cylinder 10 is passed, and the outer periphery of the intermediate portion in the longitudinal direction of the inner cylinder 10 is maintained at an appropriate gap interval A. The end portion on the biomass supply side of the outer cylinder 22 is provided with an opening 23 for both introduction and discharge of hot air, while the introduction of hot air is similarly applied to the end portion on the biomass discharge side. An opening 24 for discharging is provided.

  A heat retaining caster 25 is provided around the inner peripheral wall of the outer cylinder 22 and a baffle plate 26 that prevents the flow of hot air introduced into the gap space A is attached in a staggered manner to increase the passage time of the hot air. The amount of retained heat is used as effectively as possible for heating the woody biomass in the inner cylinder 10.

  The inner cylinder 10 of the carbonization furnace 2 is provided with an inner cylinder temperature sensor 27 such as a thermocouple for detecting the inner cylinder temperature on the woody biomass supply side. As an installation position of the inner cylinder temperature sensor 27, for example, it may be provided near the end of the outer cylinder 22 on the woody biomass supply side. A transmitter 28 that takes in and transmits the signal data of the inner cylinder temperature detected by the inner cylinder temperature sensor 27 is fixed to the outer peripheral surface of the inner cylinder 10 that is a rotating body. A receiver 29 for receiving the signal data transmitted from the transmitter 28 in a non-contact manner is installed on the ground surface or the like which is separated from the ground surface, and the inner cylinder temperature signal data received by the receiver 29 is received. A radio telemeter device 30 configured to sequentially output to an operation controller to be described later is provided.

  On the other hand, the hot-air generating furnace 3 is provided with a substantially L-shaped furnace body 31 that burns and decomposes wood gas containing a combustible tar component derived from the carbonization furnace 2 through the wood gas outlet duct 4. The furnace main body 31 has a furnace length that takes about 2 seconds or more for the introduced wood gas to pass through, and includes a combustible tar component contained in the wood gas generated by the carbonization treatment of the woody biomass, While passing through the inside of the furnace body 31 maintaining a high-temperature atmosphere such as fine unburned combustibles such as fine carbides, it is completely burned and decomposed by self-combustion, and the hot air generated at that time is supplied to the hot-air supply duct 5. It supplies to the carbonization furnace 2 via.

  32 in the figure is an auxiliary burner for supplying hot air into the furnace main body 31 using fossil fuel such as A heavy oil and propane gas, and is burned in a limited manner such as at the start of operation, in the furnace main body 31. In addition, the inner cylinder 10 of the downstream carbonization furnace 2 is preheated to a desired temperature and extinguished after completion of the preheating.

  Moreover, the hot air supply duct 5 downstream of the hot air generator 3 is branched halfway, and one branch duct 5a is connected to the opening 23 provided at the biomass supply side end of the carbonization furnace outer cylinder 22, while the other The branch duct 5b is connected to the opening 24 provided at the discharge side end portion, and dampers 33 and 34 for opening and closing the flow paths are provided in the middle of the branch ducts 5a and 5b, respectively, so as to be freely opened and closed.

  Further, the branch duct 5a is re-branched downstream of the position of the damper 33 to provide an exhaust branch duct 6a, while the other branch duct 5b is also re-branched downstream of the damper 34 position. A branch duct 6b for exhaust is provided, and the other ends of the branch ducts 6a and 6b are connected to the downstream exhaust duct 6 and merged. Further, dampers 35 and 36 for opening and closing the flow paths are provided in the middle of the branch ducts 6a and 6b, respectively, so as to be opened and closed.

  37 in the figure controls the opening and closing of the dampers 33, 34, 35, 36 provided in the branch ducts 5a, 5b, 6a, 6b based on the temperature of the inner cylinder on the biomass supply side of the carbonization furnace 2, An operation controller that switches the hot air supply direction to the furnace 2 to a co-current direction or a counter-current direction with respect to the biomass flow direction, an input / output unit 38 that inputs and outputs various data and control signals, and various setting values And the like, and a control unit 40 that executes various controls based on the various data and setting values.

  In the setting storage unit 39, for example, a reference inner cylinder temperature, which is a guideline inner cylinder temperature at which high-content woody biomass hardly adheres to the inner cylinder inner wall surface, and hot air supplied to the carbonization furnace 2 are arranged. A heating mode in which the opening / closing operation of each of the dampers 33, 34, 35, 36 in the case of flowing in the flow direction or the counterflow direction is registered is stored. In addition, as the reference inner cylinder temperature, for example, a wood gas generation temperature considered that almost no moisture causing the adhesion remains in the biomass can be suitably used. It is advisable to set and register a temperature of about 300 ° C.

  Further, in the heating mode, for example, when the co-current heating mode is selected, the dampers 33 and 36 of the branch ducts 5a and 6b are opened, the dampers 34 and 35 of the branch ducts 5b and 6a are closed, and the hot air While the hot air supplied from the generator 3 is made to flow in the direction indicated by the solid line arrow in the drawing, that is, in the parallel flow direction, when the countercurrent heating mode is selected, the dampers 34 of the branch ducts 5b and 6a are selected. , 35 are closed, and the dampers 33, 36 of the branch ducts 5a, 6b are closed so that the hot air supplied from the hot air generating furnace 3 flows in the direction indicated by the two-dot chain line arrow in FIG. ing.

  Further, the control unit 40 compares the inner cylinder temperature detected by the inner cylinder temperature sensor 27 of the carbonization furnace 2 with the reference inner cylinder temperature registered in the setting storage unit 39, and detects the detected value of the inner cylinder temperature. If the temperature is less than the reference inner cylinder temperature, the cocurrent flow mode is selected manually or automatically, and the dampers 33, 34, 35, 36 are controlled to open and close as described above according to the cocurrent flow mode. When the detected value of the inner cylinder temperature is equal to or higher than the reference inner cylinder temperature, the countercurrent heating mode is selected manually or automatically, and the dampers 33, 34 are selected according to the countercurrent heating mode. , 35 and 36 are controlled to open and close, and the hot air flows in the countercurrent direction.

  Further, in the middle of the wood gas outlet duct 4 connecting the inner cylinder 10 of the carbonization furnace 2 and the hot air generating furnace 3, the wood gas led out from the inner cylinder 10 of the carbonization furnace 2 and the outside air are heat-exchanged, An air-cooled heat exchanger 41 that condenses a part of the high-boiling tar component contained in the gas so as to be separated and recovered is interposed.

  The air-cooled heat exchanger 41 has a plurality of steel pipes 43 of a predetermined diameter vertically piped in a vertically long casing 42 whose interior is divided into three chambers, an upper chamber, a middle chamber, and a lower chamber. While the lower end opening of the steel pipe 43 is opened in the lower layer chamber 44c, the wood gas introduced into the upper layer chamber 44a from the wood gas outlet duct 4 passes through the steel pipe 43 into the lower layer chamber 44c. The configuration is derived.

  Further, reference numeral 45 in the figure denotes an outside air supply fan, which is preferably provided with an inverter, for example, so that the air flow rate can be varied. The outside air supplied from the outside air supply fan 45 is introduced into the middle layer chamber 44b of the air-cooling heat exchanger 41, and the high-temperature wood gas flowing in the steel pipe 43 is cooled while passing through the middle of the steel pipe 43, A part of the boiling point tar component is condensed and separated from the wood gas, dropped into a recovery tank 46 provided at the bottom of the lower layer chamber 44c, and a drum can 49 provided at a lower position through a discharge pipe 48 having an opening / closing valve 47. The wood gas from which a part of the tar component is separated and removed is sent out from the downstream wood gas outlet duct 4 to the hot air generating furnace 3.

  Further, the outside air supplied from the outside air supply fan 45 into the middle layer chamber 44b and heated by heat exchange with the wood gas generates the hot air through the combustion air supply duct 50 having a base end connected to the middle layer chamber 44b. The furnace 3 is supplied with combustion air for self-combustion. In the middle of the combustion air supply duct 50, an outside air introduction port 51 is provided. The outside air introduction port 51 can be freely adjusted by an opening / closing damper 52. When the opening / closing damper 52 is opened, An appropriate amount of outside air is introduced into the hot air generating furnace 3 through the combustion air supply duct 50 from the outside air introduction port 51.

  Further, in the middle of the hot air supply duct 5 on the downstream side of the hot air generating furnace 3, a hot air temperature sensor 53 for detecting the temperature of the hot air derived from the hot air generating furnace 3 and an oxygen concentration sensor 54 for detecting the residual oxygen concentration in the hot air. And.

  55 in the figure is a hot air temperature that separates and recovers a tar component corresponding to the excess heat amount from the wood gas derived from the carbonization furnace 2 to adjust and control the amount of tar combustion in the hot air generating furnace 3 to maintain the hot air temperature at a predetermined temperature. It is a tar combustion amount controller that is an adjusting means, and controls the outside air supply fan 45 of the air-cooled heat exchanger 41 based on the hot air temperature detected by the hot air temperature sensor 53 and generates it in the hot air generator 3. The hot air temperature is adjusted.

  For example, the hot air temperature sensor 53 detects and sets a temperature range of hot air suitable for carbonizing a carbide having desired properties in the carbonization furnace 2 in the tar combustion amount controller 55. If it is determined that the temperature of the hot air to be performed is higher than the preset temperature range, the outside air supply fan 45 is operated to supply outside air into the middle layer chamber 44b of the casing 42, and surplus heat is generated from the wood gas flowing in the steel pipe 43. The tar component is separated and recovered, the amount of tar combustion in the hot air generating furnace 3 is reduced, and the hot air temperature led out from the hot air generating furnace 3 to the carbonizing furnace 2 can be maintained within the temperature range. When the hot air temperature falls below the set temperature, for example, the amount of outside air supplied from the outside air supply fan 45 is reduced, or the auxiliary burner 32 provided in the hot air generating furnace 3 is temporarily burned. May be.

  Further, a combustion air supply fan for supplying combustion air for self-combustion to the hot air generating furnace 3 is separately provided, and the outside air supplied from the outside air supply fan 45 to the air-cooled heat exchanger 41 is released into the atmosphere. However, as in this embodiment, the outside air whose temperature has been raised by heat exchange with the wood gas is supplied to the hot-air generating furnace 3 through the combustion air supply duct 50 and used as combustion air for self-combustion. This effectively increases the combustion efficiency.

  However, in this case, for example, if the hot air temperature detected by the hot air temperature sensor 53 falls below a preset temperature range, the tar combustion amount controller 55 determines that there is no excess heat amount, and the outside air supply fan 45 is turned on. Since the outside air is not supplied and the supply of outside air is not performed, the combustion air is not supplied to the hot air generating furnace 3, resulting in insufficient oxygen concentration, and even when the outside air supply fan 45 has all the operating conditions and the outside air is supplied. , This outside air is thermally expanded by heat exchange with high temperature wood gas, and the oxygen amount per unit air amount (oxygen concentration) is lowered, resulting in insufficient oxygen concentration. There is a risk of burning or misfire.

  Therefore, the tar combustion amount controller 55 sets a lower limit residual oxygen concentration that is a residual oxygen concentration in the exhaust gas when the wood gas derived from the carbonization furnace 2 is completely burned by self-combustion at the minimum necessary oxygen concentration. In addition to registering, the residual oxygen concentration in the hot air detected by the oxygen concentration sensor 54 is sequentially taken, and when it is lower than the lower limit residual oxygen concentration, it is determined that the oxygen concentration is insufficient, regardless of the hot air temperature. The open / close damper 52 of the outside air introduction port 51 is opened so that room temperature outside air is introduced into the hot air generating furnace 3.

  Further, the middle of the wood gas outlet duct 4 is branched, and one side is connected to the air-cooled heat exchanger 41, while the other side is not passed through the air-cooled heat exchanger 41, and the downstream side wood gas outlet duct 4 serves as a bypass duct 56. In the middle of each duct, dampers 57 and 58 may be provided so as to be openable and closable. For example, when the hot air temperature is less than the above temperature range, it adheres to the inside of the steel pipe 43 of the air-cooled heat exchanger 41. When performing maintenance such as removing tar components, the dampers 57 and 58 are controlled to open and close so that the wood gas flows to the bypass duct 56 side.

  The hot air supplied into the outer cylinder 22 of the carbonization furnace 2 still has a considerable amount of heat even when discharged from the outer cylinder 22 because the carbonization furnace 2 is an indirect heating method, If a drying furnace or the like for drying the woody biomass before carbonization is provided in the middle of the exhaust duct 6 and the exhaust gas is supplied to the drying furnace, the stored heat amount of the exhaust gas can be effectively used without waste. Become. Further, in place of the drying furnace, for example, a sand dryer for drying sand as a raw material of the asphalt mixture may be interposed, so that the retained heat amount of the exhaust gas can be effectively used as described above.

  And when carbonizing the carbide suitable for the charcoal fuel for burners, etc. from the woody biomass such as bark having a high water content, for example, using the woody biomass carbonization apparatus 1 having the above-described configuration, first, the biomass Suitable for heating the biomass in the inner cylinder 10 to the above-mentioned heating temperature range, which is suitable for carbonizing with a certain amount of tar component left (for example, about 400-500 ° C.) A hot air temperature range (for example, about 900 to 1000 ° C.) in the outer cylinder 22 is obtained in advance by experiments or the like, and the hot air temperature range is set and registered in the tar combustion amount controller 55 together with the lower limit residual oxygen concentration. A reference inner cylinder temperature (for example, about 300 ° C.) capable of suppressing the adhesion of biomass to the inner wall surface of the inner cylinder 10 is set and registered in the operation controller 37.

  Next, the operation controller 37 selects the co-current heating mode, and opens the dampers 33 and 36 of the branch ducts 5a and 6b according to the co-current heating mode, while the dampers 34 of the branch ducts 5b and 6a. , 35 is closed, and the flow direction of hot air supplied from the hot air generating furnace 3 is adjusted to a parallel flow direction with respect to the flow direction of biomass in the inner cylinder 10, and then the auxiliary burner 32 of the hot air generating furnace 3 is ignited and burned. Then, preheating is performed by supplying hot air to the carbonization furnace 2. At this time, in the carbonization furnace 2, since the hot air flows in a direction parallel to the biomass supply direction, the temperature of the carbonization furnace inner cylinder 10 on the biomass supply side where adhesion easily occurs is quickly raised.

  When the inner cylinder temperature detected by the inner cylinder temperature sensor 27 is equal to or higher than the preset reference inner cylinder temperature, the operation controller 37 selects the countercurrent heating mode manually or automatically, While the dampers 34 and 35 of the branch ducts 5b and 6a are opened according to the flow heating mode, the dampers 33 and 36 of the branch ducts 5a and 6b are closed, and the flow direction of the hot air is made to flow down the biomass in the inner cylinder 10. After switching to the countercurrent direction with respect to the direction, biomass is supplied into the carbonization furnace inner cylinder 10 by a predetermined amount.

  The biomass supplied into the carbonization furnace inner cylinder 10 flows down while being scraped up by a plurality of scraping blades 9 provided in the furnace without adhering to the inner wall surface of the inner cylinder 10, and hot air is generated during that time. The carbon dioxide is heated indirectly and in a reducing atmosphere by the hot air supplied from the furnace 2 into the outer cylinder 22 in the reducing atmosphere, and is carbonized to be recovered as a desired state of carbide with some tar components remaining. At this time, carbonization can be efficiently performed by flowing hot air in the counterflow direction with respect to the biomass flow-down direction.

  When a sufficient amount of wood gas starts to be generated from the carbonization furnace 2 and the carbonization treatment operation becomes stable, the auxiliary burner 32 is extinguished and the operation shifts to the self-sustained combustion operation. At this time, if the hot air temperature detected by the hot air temperature sensor 53 provided in the hot air supply duct 5 downstream of the hot air generating furnace 3 falls below the preset temperature range registered in advance, the tar combustion amount controller 55 performs air-cooling heat exchange. While reducing the amount of outside air supplied from the outside air supply fan 45 to the vessel 41 to increase the amount of tar combustion in the hot air generating furnace 3, if the hot air temperature is equal to or higher than the set temperature range, the amount of outside air supplied is increased to increase the hot air generating furnace 3. The hot air temperature derived from the hot air generating furnace 3 is maintained within the set temperature range.

  Further, the remaining oxygen concentration in the hot air detected by the oxygen concentration sensor 54 is sequentially taken, and if the lower limit remaining oxygen concentration set in advance is registered, the open / close damper 52 of the outside air inlet 51 is opened to open the hot air generating furnace. 3. Introduce outside air into the interior to prevent problems such as incomplete combustion and misfire.

  In addition, even if the hot air temperature derived | led-out from the hot air generation furnace 3 becomes too low by the variation in the property (moisture content etc.) of the woody biomass to carbonize, even if the external air supply from the external air supply fan 45 is stopped, the said set temperature range If it is less, the auxiliary burner 32 of the hot air generating furnace 3 may be reignited to temporarily increase the amount of hot air.

  As described above, according to the woody biomass carbonization apparatus 1 of the present invention, at the start of operation at a low inner cylinder temperature of the carbonization furnace 2, the inner cylinder temperature on the biomass supply side is rapidly increased by the cocurrent flow method. Thus, it is possible to effectively suppress the growth of biomass on the inner wall surface of the inner cylinder 10. In addition, if the inner cylinder temperature is high enough to suppress the adhesion of biomass, switching to the countercurrent heating method enables operation with priority on heating efficiency, while maintaining both maintenance and heating efficiency. The woody biomass can be suitably carbonized.

  At this time, there is a concern that the temperature of the carbonization furnace inner cylinder 10 on the biomass supply side, which is the downstream side of the hot air, may be decreased again by switching the hot air direction to the countercurrent direction during the carbonization treatment operation. This is an indirect heating system in which heat exchange is not performed with biomass that is non-contact, that is, the hot air temperature is unlikely to decrease, and a heat retaining caster 25 is provided around the inner peripheral wall of the outer tube 22 through which the hot air passes. Therefore, in practice, the hot air outlet temperature does not decrease that much, and it is considered that there is little risk of biomass adhesion. However, if the temperature of the carbonization furnace inner cylinder 10 is nevertheless lower than the reference inner cylinder temperature, the hot air flow direction may be temporarily returned to the parallel flow direction even during operation, or the auxiliary The burner 32 may be re-ignited, and by doing so, adhesion of biomass to the inner wall surface of the inner cylinder 10 can be more effectively prevented.

  In this embodiment, the branch ducts 5a, 5b, 6a, and 6b are provided with the dampers 33, 34, 35, and 36 for opening and closing the flow path in order to switch the flow direction of the hot air between the parallel flow and the counter flow. However, the present invention is not necessarily limited thereto. For example, a flow switching valve (three-way valve) or the like may be provided at the branch portion of the hot air supply duct 5 or the branch portions of the branch ducts 5a and 5b. Various modifications can be made such as the ducts 5a and 5b and the branch ducts 6a and 6b may be separately connected to the outer cylinder 22 without being merged.

  Further, in this embodiment, an example is described in which a co-current heating method is used at the start of operation and the like, and the counter-current heating method is switched when the inner cylinder temperature on the biomass supply side rises. Of course, they can be used appropriately and flexibly within a range that does not deviate from the gist of the present invention, such as heating only by the cocurrent heating method or heating only by the countercurrent heating method.

  INDUSTRIAL APPLICABILITY The present invention can be widely used as a carbonization apparatus for various woody biomass including difficult-to-use materials such as pruned branches, root removal materials, and bark.

DESCRIPTION OF SYMBOLS 1 ... Woody biomass carbonization apparatus 2 ... Carbonization furnace 3 ... Hot air generation furnace 4 ... Wood gas extraction duct 5 ... Hot air supply duct 5a, 5b, 6a, 6b ... Branch duct 6 ... Exhaust duct 10 ... Inner cylinder (carbonization furnace 22 ... Outer cylinder (carbonization furnace)
27 ... Inner cylinder temperature sensor 30 ... Wireless telemeter device 32 ... Auxiliary burner 33, 34, 35, 36 ... Damper 37 ... Operation controller 41 ... Air-cooled heat exchanger (hot air temperature adjusting means)
45 ... Outside air supply fan (hot air temperature adjusting means)
53. Hot air temperature sensor (hot air temperature adjusting means)
55. Tar combustion amount controller (hot air temperature adjusting means)

Claims (4)

  A carbonization furnace for carbonizing wood biomass in an indirect heating type rotary kiln, a hot air generating furnace for burning and decomposing wood gas generated by carbonization of the carbonization furnace, and hot air generated in the hot air generating furnace A hot air supply duct for supplying to the outer cylinder of the carbonization furnace, branching the hot air supply duct in the middle, and connecting one branch duct to the biomass supply side end of the carbonization furnace outer cylinder, Branch ducts are connected to the discharge side end, and each branch duct is provided with a damper for opening and closing the flow path, and each damper is manually or automatically based on the inner cylinder temperature on the biomass supply side of the carbonization furnace. A wood-based biomass carbonization treatment apparatus comprising an operation controller for switching the flow of hot air to a parallel flow direction or a countercurrent direction with respect to the flow direction of biomass in the carbonization furnace   The apparatus for carbonizing woody biomass according to claim 1, further comprising hot air temperature adjusting means for maintaining a hot air temperature downstream of the hot air generating furnace at a predetermined temperature.   The hot air temperature adjusting means allows heat exchange between the wood gas derived from the carbonization furnace and the outside air supplied from the outside air supply fan to condense and separate and recover a part of the high boiling point tar component contained in the wood gas. The air-cooling heat exchanger according to claim 2 and a tar combustion amount controller for adjusting and controlling the amount of tar combustion in the hot air generator by adjusting the amount of outside air supplied from the outside air supply fan. Carbonizing equipment for woody biomass.   It is a driving | operation method of the carbonization processing apparatus of the woody biomass in any one of Claims 1 thru | or 3, Comprising: The flow of the hot air which generate | occur | produces in a hot-air generator at the time of an operation | movement is with respect to the flow direction of the biomass in a carbonization furnace. When the carbonization furnace is heated as a parallel flow direction, and the inner cylinder temperature on the biomass supply side of the carbonization furnace is equal to or higher than a predetermined temperature, the flow of hot air generated in the hot air generation furnace is countercurrently directed to the biomass flow direction. After switching so that it becomes, the carbonization processing method of the wood type biomass characterized by supplying biomass into a carbonization furnace and carbonizing.

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