JP4504337B2 - Gasifier and gasifier system - Google Patents

Description

  The present invention relates to a gasification furnace that efficiently gasifies woody biomass, and more particularly to a fixed bed type gasification furnace.

  In recent years, an increase in waste generated by mass production and mass consumption has become a major social problem in Japan, and effective use of resources is desired. In addition, as a measure against global warming, it is necessary to switch from power generation using fossil fuels to natural energy such as solar, wind power and hydropower. On the other hand, effective use of wood resources such as thinned wood and offcuts generated from forest and wood processing, so-called wood biomass, is being studied. Wood biomass utilization technologies include (1) direct combustion, (2) gasification technology, (3) ethanolation, and (4) solidification. In direct combustion, wood is burned in a boiler, steam is extracted from the waste heat boiler using the combustion heat, and power is generated by a boiler turbine or the heat of the steam is used. In addition, gasification technology is a method in which wood is pyrolyzed under low oxygen, and the generated combustible gas (carbon monoxide, hydrogen, methane, etc.) is used to generate power with a gas engine, or steam is blown into the generated gas to generate gas. To produce hydrogen, methanol and the like. Ethanolation is a method in which cellulose or the like in wood is hydrolyzed and saccharified and fermented with yeast or the like to produce ethanol. Solidification is the compression of wood into solid fuel, or carbonization and use as charcoal. Among them, gasification technology is attracting attention as a cogeneration system capable of supplying thermoelectric power because it can be expected to have high power generation efficiency and heat recovery rate even on a small scale.

Gasification furnaces used in gasification technology include direct gasification methods (fixed-bed and fluidized-bed furnaces) in which a small amount of air is placed in the furnace and indirect gas that heats the furnace from the outside without introducing air into the furnace. For example, a conversion method (rotary kiln type) has been proposed. Among them, the fixed-bed furnace has the characteristics that a contact time between a carbonaceous solid material such as a wood chip and a gas material can be increased, the furnace structure is simple, and the operation is relatively easy. . For example, as a fixed-bed furnace, a carbonaceous solid material introduction part is provided in the upper part of the furnace, an air intake is provided in the center part, a grate is provided in the lower part, and a generated gas outlet part is provided below the grate. A provided downdraft type gasification furnace has been proposed (for example, Patent Documents 1 and 2).
Special Table 2000-505123 JP 2002-285172 A

  However, there is a need for a gasification furnace having high thermal efficiency and a more compact structure for practical use.

  Therefore, an object of the present invention is to provide a gasification furnace having high thermal efficiency and a more compact structure.

In order to solve the above problems, the gasification furnace of the present invention is supplied with a carbonaceous solid material, and an upper chamber that performs low-temperature processing on the carbonaceous solid material;
The upper chamber communicates with the upper chamber, and the upper end is disposed so as to form a gap with respect to the lower end of the upper chamber. The carbonaceous solid material supplied from the upper chamber is subjected to a high temperature treatment to generate a combustible gas. The lower chamber,
A grate portion disposed at the lower end of the lower chamber;
An outer peripheral passage formed so as to surround the lower chamber and connected to a gap between the upper chamber and the lower chamber, while being disconnected from a lower end of the lower chamber;
A first doorway connected to the outer peripheral passage,
And a second doorway connected to the lower end of the lower chamber, and an ignition part is disposed in a gap between the upper chamber and the lower chamber .

  As an example of carbonaceous solid material, gasification of woody biomass is made by reacting the moisture of carbon dioxide produced by combustion (oxidation) of woody material with combustion charcoal (reduction), carbon monoxide, hydrogen, methane, etc. It is a reaction that converts to flammable gas. The gasification furnace of the present invention is a fixed bed type gasification furnace, and a so-called downdraft system in which a gaseous material is sent downward from the upper end of the lower chamber as a ventilation system of a lower chamber that performs high-temperature processing, Any of the so-called updraft methods for sending upward from the lower end of the chamber can be applied.

  When the gasification furnace of the present invention is a downdraft system, the lower chamber is subjected to processing at a lower temperature than the processing performed in the lower chamber by radiant heat from the lower chamber. Specifically, moisture in the carbonaceous solid material is evaporated and dried. The carbonaceous solid material subjected to the low temperature treatment in the upper chamber is supplied to the lower chamber. Further, the gas material is supplied from the outer peripheral passage into the lower chamber through a gap between the lower end of the upper chamber and the upper end of the lower chamber. In the lower chamber, processing is performed at a higher temperature than in the upper chamber. Specifically, a pyrolysis zone, an oxidation zone, and a reduction zone are formed in the lower chamber in order from the top. In the pyrolysis zone and the oxidation zone, solid materials are burned to produce combustion charcoal, and carbon dioxide and moisture. Is generated. In the reduction zone, carbon dioxide and moisture react with the burning charcoal to produce combustible gases such as carbon monoxide and hydrogen. In addition, a dry area may be formed on the pyrolysis area.

  On the other hand, when the gasification furnace of the present invention is an updraft system, the carbonaceous solid material is dried in the upper chamber by low-temperature treatment, as in the downdraft system. In the lower chamber, an oxidizing area is formed on the grate portion by supplying the gaseous material from the lower end. That is, a high temperature treatment is performed in the lower chamber, and a pyrolysis zone, a reduction zone, and an oxidation zone are formed in order from the top. Carbon dioxide and moisture generated in the oxidation zone react with the combustion charcoal in the reduction zone to become a combustible gas such as carbon monoxide and hydrogen, and are discharged to the outer peripheral passage through the thermal decomposition zone. In addition, a dry area may be formed on the pyrolysis area.

  According to the gasification furnace of the present invention, in either the downdraft system or the updraft system, the heat insulation effect of the lower chamber can be obtained by the outer peripheral passage surrounding the lower chamber. Thereby, heat insulation of a lower chamber can be performed using fewer heat insulating materials than the case where an outer periphery channel | path is not provided. Therefore, since the arrangement space of the heat insulating material in the gasification furnace can be reduced, the gasification furnace can be downsized.

Moreover, according to the said structure , the carbon solid material in an upper chamber and a lower chamber can be ignited by the said ignition part. Since gas is easy to flow through the gap, for example, oxygen or the like can be easily supplied to easily ignite the carbon solid material.

  The gasification furnace of one embodiment is formed so that the inside of the upper chamber or the lower chamber can be visually recognized from the outside through the gap between the upper chamber and the lower chamber.

  According to the above embodiment, for example, by providing a visual window on the wall surrounding the upper chamber and the lower chamber, the upper chamber is formed from the outside of the gasification furnace using the gap that is a passage for the gas material and the combustible gas. And the situation in the lower room can be monitored.

  In the gasification furnace of one embodiment, the lower chamber has a cylindrical shape, and an annular protrusion that extends in the circumferential direction and protrudes inward in the radial direction is provided on the inner surface of the lower chamber.

  According to the embodiment, at the position where the annular protrusion is provided, the flow rate of the gas flowing through the lower chamber increases and the temperature of the gas increases. Thereby, in any of the downdraft type and the updraft type, a combustible gas having a high calorific value and a high combustion rate can be obtained.

  In the downdraft method, by arranging the annular protrusion at a position corresponding to the oxidation zone, the gas whose temperature has been raised can be pushed from the oxidation zone to the reduction zone at a high speed, thereby decomposing the tar contained in the gas. Can be promoted. When tar is decomposed, it becomes a combustible gas such as carbon monoxide, hydrogen, and methane, so that the gasification efficiency of the carbon solid material can be improved as compared with the case where tar remains. In particular, since the amount of hydrogen component in the generated gas can be increased, a combustible gas having a high calorific value and high combustion rate can be obtained.

  On the other hand, in the updraft type, by arranging the annular protrusion at a position corresponding to the thermal decomposition zone, the gas whose temperature has increased can be discharged from the upper end of the lower chamber to the outer peripheral passage through the gap. Thereby, the temperature of the upper chamber which opposes across the said clearance gap can be raised, and the carbonaceous solid material in this upper chamber can fully be dried. As a result, the temperature in the lower chamber where the high-temperature treatment of the carbonaceous solid material can be sufficiently increased, and the amount of hydrogen component of the generated gas can be increased, so that a combustible gas having a high calorific value and combustion rate can be obtained. .

  The gasification furnace of one embodiment is configured such that the grate has a conical shape and is rotationally driven around an axis in a state where the upper end portion is inserted into the lower chamber.

  According to the embodiment, the ash generated by the high temperature treatment in the lower chamber can be efficiently discharged from the lower chamber by rotationally driving the grate.

  In the gasification furnace according to an embodiment, the grate has a plurality of annular portions arranged so that the diameters are sequentially increased from the upper end toward the lower end side.

  According to the above embodiment, the ash on the grate is distributed to the inside and the outside in each annular part, and the ash that has moved to the inside of the annular part falls downward as it is, and moves to the outside of the annular part. The ash is distributed to either the inner side or the outer side at the annular part adjacent to the lower side. As described above, the ash on the grate is sequentially distributed to the inner side and the outer side of each annular portion as it moves downward along the grate, so that it is discharged substantially uniformly below the grate. In addition, it is preferable that the said annular part forms a surrounding surface in an inclined surface, and makes the inclination angle of this inclined surface substantially the same as the repose angle of the ash obtained by processing a carbon solid material at high temperature. Moreover, it is preferable that each annular part is arrange | positioned without a space | gap mutually in planar view of a grate.

  The gasification furnace of one embodiment is equipped with a scraper that is driven as the grate rotates and removes ash that accumulates between the lower end of the lower chamber and the second doorway.

  According to the embodiment, by removing the ash with the scraper, it is possible to secure a gas material or a combustible gas passage between the lower end of the lower chamber and the second doorway.

  In the gasification furnace of one embodiment, a gaseous material is supplied from the first inlet / outlet, and the gaseous material flows into the gap between the lower end of the upper chamber and the upper end of the lower chamber via the outer peripheral passage. A downward flow is formed in the lower chamber, and the combustible gas generated in the lower chamber is discharged from the second inlet / outlet.

  According to the above embodiment, a downdraft type gasification furnace in which a downward flow is formed in the lower chamber is obtained.

  In the gasification furnace of one embodiment, a gaseous material is supplied from the second inlet / outlet, and the gaseous material flows into the lower end of the lower chamber to form an upward flow in the lower chamber, which is generated in the lower chamber. The combustible gas is discharged from the first inlet / outlet through the outer peripheral passage.

  According to the embodiment, an updraft type gasification furnace in which an upward flow is formed in the lower chamber is obtained.

The gasifier system of the present invention includes the above gasifier,
A positive displacement blower connected to one of the first inlet and the second inlet and outlet of the gasifier and supplying a gas material to the gasifier;
Control which controls the quantity of combustible gas discharged from the other of the 1st entrance and the 2nd entrance / exit of the gasification furnace by controlling the flow of the gaseous material which the capacity type blower supplies to the gasification furnace It is characterized by providing a part.

  According to the above configuration, by using the positive displacement blower, the flow rate of the gas material supplied to the gasification furnace can be accurately controlled without being affected by the pressure fluctuation of the gasification furnace. Therefore, by controlling the flow rate of the gas material supplied to the gasifier by the positive displacement blower by the controller, the amount of combustible gas generated and discharged in the gasifier is controlled with high accuracy. Can do. Since this gasification furnace system can control the amount of combustible gas with high accuracy, for example, boiler temperature control, gas engine speed control, and the like can be performed.

  According to the present invention, since the heat insulation effect of the lower chamber can be obtained by the outer peripheral passage that surrounds the lower chamber, it is possible to insulate the lower chamber using less heat insulating material than when no outer peripheral passage is provided, and the downdraft method A gasification furnace that can be reduced in size can be obtained by applying either of the above and the updraft method.

Hereinafter, the drying apparatus of the present invention will be described in detail with reference to the illustrated embodiments.
(First embodiment)
FIG. 1 is a schematic cross-sectional view showing the structure of the gasification furnace according to the first embodiment, and shows an example of a so-called downdraft type gasification furnace in which a gas material is vented downward through the reaction furnace. The gasification furnace A includes a reaction furnace 1 as a lower chamber having a cylindrical shape, a supply drying furnace 2 as an upper chamber disposed above the reaction furnace 1 and having a cylindrical shape, and a lower end portion of the reaction furnace 1. The grate 12 is provided. A cylindrical inner wall 8 is arranged outside the radial direction of the reaction furnace 1 at a predetermined interval. A substantially cylindrical shape is formed between the inner peripheral surface of the inner wall 8 and the outer peripheral surface of the reaction furnace 1. An outer peripheral passage 9 is formed. Below the reaction furnace 1, a lower end chamber 3 that communicates with the lower end of the reaction furnace 1 and stores the ash generated in the reaction furnace 1 is disposed. The lower half of the supply drying furnace 2, the reaction furnace 1 and the outer peripheral passage 9, and the upper half of the lower end chamber 3 are accommodated in the casing 6. The casing 6 is provided with an air supply part 4 as a first entrance and a gas discharge part 5 as a second entrance. The air supply unit 4 is connected to an opening provided in the inner wall 8 and communicates with the outer peripheral passage 9. Further, the gas discharge part 5 is connected to an opening provided in the wall surface of the lower end chamber 3 and communicates with the lower end chamber 3.

  A gap of a predetermined distance is provided between the upper end of the reaction furnace 1 and the lower end of the supply drying furnace 2 to form a gap passage 10. The outer peripheral passage 9, the inside of the reaction furnace 1, and the inside of the supply drying furnace 2 communicate with each other through the gap passage 10. The inner diameter of the reaction furnace 1 is formed larger than the inner diameter of the supply drying furnace 2, and a radial step is formed between the reaction furnace 1 and the supply drying furnace 2. The distance of the step and the separation distance of the gap passage 10 have the following relationship. That is, for a right triangle that has a radial step as a base and a right angle with the base and the height of the separation of the gap passage 10, the tangent of the right triangle is made smaller than the tangent of the repose angle of the solid material. . Thereby, the solid material supplied to the reaction furnace 1 from the supply drying furnace 2 is prevented from leaking out from the gap passage 10.

  The outer peripheral passage 9 surrounds the outer peripheral surface of the reaction furnace 1 and communicates with the air supply unit 4 through an opening formed in the inner wall 8. The gas material supplied from the air supply unit 4 to the outer peripheral passage 9 flows along the outer peripheral surface of the reaction furnace 1 and flows into the reaction furnace 1 through the gap passage 10. As a result, the gas material passing through the outer peripheral passage 9 exchanges heat with the reaction furnace 1 and rises in temperature, and heat from the reaction furnace 1 is hardly released to the outside of the outer peripheral passage 9. That is, by the outer peripheral passage 9, the gas material flowing into the reaction furnace 1 can be preheated to improve the heating efficiency, and the heat insulation effect for the reaction furnace 1 can be obtained.

  Outer heat insulating materials 42, 43, and 44 are disposed between the casing 6 and the supply drying furnace 2, between the casing 6 and the inner wall 8, and between the casing 6 and the lower end chamber 3, respectively. The outer heat insulating material 43 between the casing 6 and the inner wall 8 can be constituted by fewer heat insulating materials than directly insulating the reaction furnace 1 because the heat insulating effect of the reaction furnace 1 is obtained by the outer peripheral passage 9. Thereby, the usage-amount of the heat insulating material in the casing 6 is reduced effectively, and the gasification furnace A can be reduced in size.

  On the inner wall surface of the reaction furnace 1, an annular protrusion 11 that extends in the circumferential direction and protrudes inside the reaction furnace 1 is provided. The annular protrusion 11 is provided slightly above the center of the reaction furnace 1 in the height direction. A gas material is supplied into the reaction furnace 1 from the upper end through the gap passage 10, whereby the gas flows downward through the annular protrusion 11 and reaches the grate portion 3.

  Here, the temperature of the gas flowing in the reaction furnace 1 is increased because the passage area is narrowed in the annular protrusion 11. The annular protrusion 11 can be provided in any region corresponding to the above-described drying zone, pyrolysis zone, oxidation zone, and reduction zone, but is preferably provided in a zone corresponding to the oxidation zone. This is because the high-temperature gas that has passed through the annular protrusion 11 is pushed into the reduction zone, so that tar decomposition can be promoted. The shape of the annular protrusion is not particularly limited as long as it protrudes into the furnace body and narrows the gas passage area, but it is preferably a step shape having a rectangular shape on the cut surface passing through the axis of the reaction furnace 1. . This is because, by using the step shape, the gas velocity can be increased at a stretch and the temperature of the gas can be greatly increased. Further, the step shape has an advantage that the manufacturing is easy and the manufacturing cost can be reduced. The height of the annular protrusion is not particularly limited, but preferably the height of the annular protrusion (dimension in the direction parallel to the radial direction of the reactor 1) is 1/7 to 1/2 of the reaction furnace radius. Preferably it is 1/5 to 1/3. This is because if it is less than 1/7, the effect of increasing the temperature is insufficient, and if it is more than 1/2, the supply amount of the gas material decreases, and the solid material cannot be sufficiently thermally decomposed. Further, the thickness of the annular protrusion (dimension in the direction parallel to the height direction of the reactor 1) is preferably 1/13 to 1/4 of the height of the reactor 1, more preferably 1/10 to 1 /. 5.

  Note that the areas corresponding to the drying zone, thermal decomposition zone, oxidation zone, and reduction zone in the reactor 1 can be estimated in consideration of the diameter and height of the reactor 1, respectively. An annular protrusion can be provided in the region.

  A burner 18 as an ignition part is disposed in the gap passage 10. High temperature air heated by an electric heater (not shown) is jetted from the tip of the burner 18 to ignite the solid material.

  The inner wall 8 is formed with a window in which heat-resistant glass is fitted at the same height as the gap passage 10 is formed, and one end of a hollow visual tube 19 is connected to the window. Yes. The other end of the visual recognition tube 19 projects outside the casing 6, and the inside of the reaction furnace 1 and the supply drying furnace 2 can be visually recognized from the other end of the visual recognition pipe 19 through the gap passage 10.

  A drive shaft 14 that rotationally drives the grate 12 is disposed in the lower end chamber 3. The upper end of the lower chamber 3 is connected to the lower end of the reaction furnace 1, receives ash falling from the reaction furnace 1 as the grate 12 is rotationally driven, and the combustible gas generated in the reaction furnace 1 It is formed to flow in. The drive shaft 14 is connected to a drive unit 16 attached to the bottom surface of the lower end chamber 3 and is driven to rotate by a motor in the drive unit 16. During the operation of the gasification furnace A, the solid material charged from the supply drying furnace 2 is deposited on the grate 12 in the reaction furnace 1, and the solid material changes to ash as the gasification proceeds. The generated ash is dropped by the grate 12, accumulated in the lower end chamber 3, and discharged from a discharge port (not shown). A screw conveyor is connected to the discharge port of the lower end chamber 3, and a rotary valve is provided at the discharge port of the screw conveyor to prevent pressure reduction in the furnace when ash is discharged.

  The grate 12 is preferably a laminated body in which a plurality of circular rings with different diameters are laminated and fixed in a conical shape. FIG. 2 is a schematic cross-sectional view showing an example of the grate 12. As shown in FIG. 2, the grate 12 is formed by a conical portion 121 at the upper end and a plurality of annular portions 122 and 123 arranged below the conical portion 121. In FIG. 2, for ease of understanding, only two annular portions 122 and 123 are shown, and the intervals and dimensional ratios of the annular portions 122 and 123 are highlighted. The annular parts 122 and 123 have inclined side surfaces 122a and 123a, and the inclination angle of these side surfaces is formed substantially the same as the repose angle of ash. As a result, as shown by arrows in FIG. 2, the ash that has flowed into the through holes 122 b and 123 b inside the annular portion is dropped into the lower lower end chamber 3, while along the side surfaces 122 a and 123 a of the annular portion. The ash that has flowed to the outside can be guided onto an annular ring adjacent to the lower side. Thereby, ash can be dropped almost uniformly below the grate 12. The grate is not limited to a conical shape, and may have another shape such as a lattice shape. Further, the grate need not necessarily be driven.

  A scraper 15 is provided at the upper part of the drive shaft 14 at a height substantially equal to the height at which the gas discharge part 5 is connected to the lower end chamber 3. The scraper 15 is formed by fixing a rectangular piece extending in the radial direction of the grate 12 to the drive shaft 14. When the drive shaft 14 is rotated, the scraper 15 is rotated to prevent ash from adhering to the inner wall of the lower end chamber 3. Thereby, in the lower end chamber 3, it is possible to secure a passage for guiding the combustible gas to the gas discharge unit 5. Further, fine ash floating in the generated gas can be guided to the gas discharge unit 5.

  The supply drying furnace 2 is supplied with a solid material such as a wood pellet from the upper end, and stores and dries the solid material. A heat insulating material 41 is disposed at the lower end portion of the supply drying furnace 2 so as to surround the outer periphery, and the low temperature treatment of the solid material is performed at the lower end portion of the supply drying furnace 2. That is, the solid material is dried at a temperature lower than the temperature in the reaction furnace 1 by the heat transferred from the reaction furnace 1. The supply of the solid material to the supply drying furnace 2 is performed from a storage tank (not shown) by a quantitative supply device (not shown). A supply tube 17 in which a photoelectric sensor is installed extends substantially in the upper half of the supply drying furnace 2, and the distance to the surface of the solid material is measured by the sensor to determine the amount of the solid material. measure. Based on this, the operation of the quantitative supply device is controlled so as to keep the amount of the solid material present in the gasification furnace A at a constant amount. The supply tube 17 may not be provided, and in this case, the photoelectric sensor may be provided in the supply drying furnace 2.

  Woody biomass as a carbonaceous solid material includes biomass from forests such as branches, leaves, treetops, root stocks, and thinned wood, biomass from wood processing industries such as sawdust, bark, edgewood, backboard, and construction waste Biomass from waste from. These biomasses are coarsely pulverized or finely pulverized and processed into wood chips and wood pellets, which are used as solid materials. In addition to woody biomass, for example, agricultural waste such as sugar cane, hops, or kenaf, or vegetable waste in the food industry may be used. Thus, the carbonaceous solid material widely corresponds to a solid material derived from a plant. Moreover, components derived from organisms other than plants may be included. The form of the carbonaceous solid material is not limited to pellets, and may be chips. In short, it is only necessary to have a shape and dimensions that allow gasification.

  As the gas material, a gas containing an oxidizing gas such as oxygen can be used, and preferably air is used. Moreover, air heated to normal temperature or a predetermined temperature as necessary can be used.

  When supplying the gaseous material from the air supply unit 4 into the gasification furnace A, it is preferable to keep the internal pressure of the gasification furnace A at atmospheric pressure or higher by forced air flow. This is because if the draft air is used, heat resistance is required for the blower, and maintenance of the blower becomes difficult due to tar adhesion, resulting in high costs. Moreover, it is preferable to use a positive displacement blower such as a Roots type blower or a vane type blower as the blower that performs the forced ventilation from the air supply unit 4. By using the positive displacement blower, it is possible to substantially prevent fluctuations in the amount of blown air due to pressure fluctuations in the gasification furnace A, and it is possible to supply the gas material stably.

Next, the operation of the gasifier A according to this embodiment will be described.
First, a predetermined amount of solid material is charged into the supply drying furnace 2 from the storage tank by a quantitative supply device, and the solid material is charged into the reaction furnace 1 below the supply drying furnace 2 to be solidified on the grate 12. Deposit material. Next, high temperature air is jetted from the tip of the burner 19 to ignite the solid material. Next, normal temperature air is introduced from the air supply unit 4 into the outer peripheral passage 9. The air introduced into the outer peripheral passage 9 is blown into the reaction furnace 1 from the upper end through the gap passage 10. In the reaction furnace 1, a part of the solid material is combusted and gasified to generate a combustible gas. The combustible gas passes from the lower end of the reaction furnace 1 through the gap between the reaction furnace 1 and the grate 12 and the gap of the grate 12, and is discharged from the gas discharge unit 5 through the lower end chamber 3. The flow until air is supplied from the air supply unit 4 and flammable gas is discharged from the gas discharge unit 5 is indicated by a solid arrow D in FIG.

  The supply amount of air is adjusted so that the temperature in the reaction furnace 1 is about 800 ° C. in the thermal decomposition region and about 1200 ° C. in the annular protrusion. The supply amount of air can be adjusted with high accuracy by using a positive displacement blower.

  In the gasification furnace A of the present embodiment, when the gas flowing in the reaction furnace 1 passes through the annular protrusion 11, the passage area is narrowed, so that the temperature rises. Thereby, the temperature in the reaction furnace 1 can be raised locally and the gasification efficiency of a solid material can be improved. Further, the tar generated in the pyrolysis zone is gasified when passing through the hot reduction zone. This also has the effect that tar can be removed. Therefore, since tar does not adhere to the wall surface of the gas line and block the gas line, for example, a boiler or a gas engine to which a combustible gas is supplied from the gasification furnace A can be easily maintained.

(Second Embodiment)
The gasification furnace according to the present embodiment is a so-called updraft type gasification furnace in which a gaseous material is supplied to the reaction furnace from the lower end and an upward gas flow is generated in the reaction furnace. The air supply unit 4 according to the first embodiment has the same structure as that of the first embodiment except that the gas supply unit 4 functions as a gas discharge unit and the gas discharge unit 5 functions as an air supply unit. This embodiment will be described in detail with reference to FIG.

  The operation of the gasifier according to the present embodiment will be described focusing on the differences from the first embodiment. After starting the gasification furnace, normal temperature air is introduced into the lower end chamber 3 from the air supply unit 5. The air introduced into the lower end chamber 3 passes through the gap of the grate 12 or the gap between the grate 12 and the reaction furnace 1 and is blown into the reaction furnace 1 so as to face up in the reaction furnace 1. Moving. In the reaction furnace 1, a part of the solid material is combusted and gasified to generate a combustible gas. The combustible gas flows from the upper end of the reaction furnace 1 through the clearance passage 10 into the outer peripheral passage 9, flows downward along the outer peripheral surface of the reaction furnace 1, and is discharged from the gas discharge unit 4. Is done. Thus, the flow until air is supplied from the air supply part 5 and combustible gas is discharged from the gas discharge part 4 is shown by the broken-line arrow U in FIG.

  According to the present embodiment, the temperature of the gas flowing upward in the reaction furnace 1 increases as a result of the passage area being narrowed at the position where the annular protrusion 11 is formed. Thereby, the gasification efficiency of a solid material can be improved. The annular protrusion 11 can be provided in any of the above-described drying area, pyrolysis area, reduction area, area corresponding to the oxidation area, and a boundary area extending over two adjacent areas. It is preferable to provide in a boundary region that extends over the reduction zone. This is because, as a result of the gas heated through the annular protrusion 11 being pushed into the drying zone, the solid material can be sufficiently dried, and a combustible gas having a high calorific value can be obtained. Further, according to the present embodiment, the direction in which the combustible gas flows out from the reactor 1 is the direction opposite to the direction in which the ash is directed to the lower end chamber 3, so that it is combustible compared to the downdraft type of the first embodiment. The ash content in sex gas can be greatly reduced. Therefore, the ash separation treatment of the combustible gas is easy, and higher thermal efficiency can be obtained.

(Third embodiment)
FIG. 3 is a schematic diagram showing a cogeneration system using the gasification furnace and the gasification furnace system of the present invention. This system uses wood pellets as a solid material, and supplies wood pellets from a pellet storage tank 20 to a downdraft type gasification furnace B using a quantitative feeder 21. The gasification furnace B is supplied with air as a gaseous material by a positive displacement roots blower 22. The air volume of the roots type blower 22 is controlled by the control unit C. The combustible gas generated in the gasification furnace B is supplied to the cyclone 23. Ash generated from the gasifier B and the cyclone 23 is collected by an ash conveyor 24. A part of the combustible gas treated by the cyclone 23 is sent to the boiler 25 and burned to obtain steam or hot water. On the other hand, the remainder of the combustible gas is supplied to the gas engine 29 through the cooling tower 26, the electrostatic precipitator 27, and the condenser 28, and the generator is driven by the gas engine 29 to obtain electric power. At the same time, exhaust heat is recovered from the cooling water of the gas engine 29 to obtain hot water. In the cooling tower 26, the combustible gas is cooled using water supplied from the pump 30 and air from the compressor 31.

  The cogeneration system of the present embodiment can control the steam or hot water temperature from the boiler 25 and the power output of the generator by controlling the air volume of the roots blower 22 by the control unit C. That is, by controlling the rotational speed of the rotor of the Roots-type blower 22 by the control unit C, the air flow rate from the Roots-type blower 22 to the gasifier B is controlled with high accuracy. Thereby, the amount of combustible gas produced | generated in the gasification furnace B is controlled with high precision, Therefore, the supply amount of the combustible gas to the boiler 25 and the gas engine 29 is controlled with high precision. As a result, the combustion temperature of the boiler 25 and the rotation speed of the gas engine 29 can be controlled, and the steam or hot water temperature from the boiler 25 and the output power of the generator can be controlled.

  According to the present embodiment, the use of the gasification furnace of the present invention makes it possible to use a product gas with a small amount of tar and a high calorific value, so that it is possible to improve power generation efficiency and thermal efficiency. In addition, since tar is small, tar does not adhere to the gas line and clog the gas line, and system maintenance is easy.

  In this embodiment, the example in which the generated gas from the gasification furnace B is supplied to the boiler 25 and the gas engine 29 has been described. However, the system is configured to supply the generated gas only to the boiler 25 or only to the gas engine 29. You can also. In this case, by controlling the roots type blower 22 by the control unit C, only the temperature of the steam or hot water from the boiler 25 can be controlled, or only the output power of the generator can be controlled.

  Further, the supply of air to the gasification furnace B is not limited to the roots blower 22 and may be performed using another positive displacement blower such as a vane blower or a screw blower.

  Moreover, the solid material supplied to the gasifier B is not limited to wood pellets, and plant-derived carbonaceous solid materials such as agricultural waste and food waste can be widely used. Moreover, components derived from organisms other than plants may be included. The form of the carbonaceous solid material is not limited to pellets, and may be chips.

(Fourth embodiment)
FIG. 4 is a schematic diagram showing a hot air and carbon dioxide supply system configured using the gasification furnace and the gasification furnace system of the present invention. In the present embodiment, the same components as those in the third embodiment are denoted by the same reference numerals as those in the third embodiment, and detailed description thereof is omitted.

  In the hot air and carbon dioxide supply system of the present embodiment, the combustible gas from the gasification furnace B is supplied to the combustor 32 via the cyclone 23. The combustible gas is heated and burned by a gas burner in the combustor 32, and the combustion gas is supplied to a greenhouse for crop cultivation.

  Conventionally, greenhouses for crop cultivation are heated using a heating device that burns liquid fuel such as heavy oil. Since the combustion gas contains sulfur oxides, it cannot be supplied into the greenhouse, and most of the heat of the combustion gas is wasted outside. In addition, although crops consume carbon dioxide by photosynthesis, there is a problem that the growth of crops is hindered because carbon dioxide in the greenhouse tends to be insufficient because the greenhouse is a sealed space. Therefore, carbon dioxide is supplied into the greenhouse using a cylinder or the like. In addition, although carbon dioxide exists in combustion gas, such as heavy oil, since it contains a sulfur compound as mentioned above, it cannot utilize as a carbon dioxide source.

  On the other hand, the hot air and carbon dioxide supply system using the gasification furnace and the gasification furnace system of the present invention is substantially realized by combusting the combustible gas from the gasification furnace B in the combustor 32. A clean combustion gas consisting only of carbon dioxide is obtained. It is therefore possible to supply this combustion gas directly into the greenhouse. By supplying the combustion gas directly into the greenhouse, the greenhouse can be efficiently heated by the heat of the combustion gas, and carbon dioxide can be supplied to the crop. Further, by controlling the amount of air supplied from the blower 22 to the gasifier B by the control unit C, the amount of combustion heat in the combustor 32 can be controlled, and the supply amount of room temperature and carbon dioxide can be controlled with high accuracy.

  Moreover, the solid material supplied to the gasifier B is not limited to wood pellets, and plant-derived carbonaceous solid materials such as agricultural waste and food waste can be widely used. Moreover, components derived from organisms other than plants may be included. The form of the carbonaceous solid material is not limited to pellets, and may be chips.

  As described above, the gasification furnace of the present invention can efficiently gasify a carbonaceous solid material made of woody biomass, and can produce a high calorific combustible gas. In addition, the system using the gasification furnace of this invention is not limited to embodiment, The aspect of a various system is possible in the range of this invention. Further, the carbonaceous solid material is not limited to woody biomass, and any solid material derived from plants such as plant meal contained in food waste or the like can be used.

It is a schematic cross section which shows an example of the gasification furnace of this invention. It is a schematic cross section showing an example of a grate. It is a schematic diagram which shows an example of the system using the gasification furnace of this invention. It is a schematic diagram which shows the other system using the gasification furnace of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction furnace 2 Supply drying furnace 3 Lower end chamber 4 Air supply part 5 Gas discharge part 6 Casing 8 Inner wall 9 Outer peripheral passage 10 Clearance passage 11 Annular protrusion 12 Grate 14 Drive shaft 15 Scraper 16 Drive part 17 Supply tube 18 Burner 19 Visual recognition Pipe 20 Pellet storage tank 21 Constant supply machine 22 Roots type blower 23 Cyclone 24 Ash conveyor 25 Boiler 26 Cooling tower 27 Electric dust collector 28 Condenser 29 Gas engine 30 Pump 31 Compressor 32 Combustor A, B Gasifier C Controller

Claims (9)

A carbonaceous solid material is supplied, and an upper chamber that performs low-temperature processing on the carbonaceous solid material;
The upper chamber communicates with the upper chamber, and the upper end is disposed so as to form a gap with respect to the lower end of the upper chamber. The carbonaceous solid material supplied from the upper chamber is subjected to a high temperature treatment to generate a combustible gas. The lower chamber,
A grate disposed at the lower end of the lower chamber;
An outer peripheral passage formed so as to surround the lower chamber and connected to a gap between the upper chamber and the lower chamber, while being disconnected from a lower end of the lower chamber;
A first doorway connected to the outer peripheral passage,
A gasification furnace comprising: a second doorway connected to a lower end of the lower chamber; and an ignition portion disposed in a gap between the upper chamber and the lower chamber . In the gasifier according to claim 1,
A gasification furnace characterized in that the inside of the upper chamber or the lower chamber can be visually recognized from the outside through a gap between the upper chamber and the lower chamber. In the gasifier according to claim 1,
The gasification furnace according to claim 1, wherein the lower chamber has a cylindrical shape, and an annular protrusion that extends in the circumferential direction and protrudes inward in the radial direction is provided on an inner surface of the lower chamber. In the gasifier according to claim 1,
A gasification furnace characterized in that the grate has a conical shape and is rotationally driven around an axis in a state where an upper end portion is inserted into the lower chamber. In the gasifier according to claim 4 ,
The above-mentioned grate has a plurality of annular parts arranged so that the diameter is gradually increased from the upper end toward the lower end side. In the gasifier according to claim 4 ,
A gasification furnace comprising a scraper that is driven as the grate rotates and removes ash deposited between a lower end of the lower chamber and a second doorway. In the gasifier according to claim 1,
A gaseous material is supplied from the first inlet / outlet, and the gaseous material flows into the gap between the lower end of the upper chamber and the upper end of the lower chamber via the outer peripheral passage to form a downward flow in the lower chamber. A gasification furnace characterized in that the combustible gas generated in the lower chamber is discharged from the second inlet / outlet. In the gasifier according to claim 1,
A gaseous material is supplied from the second inlet / outlet, and the gaseous material flows into the lower end of the lower chamber to form an upward flow in the lower chamber. The combustible gas generated in the lower chamber is transferred to the outer peripheral passage. A gasification furnace characterized in that the gasification furnace is configured to discharge from the first entrance / exit via the above. A gasification furnace according to any one of claims 1 to 8 ,
A positive displacement blower connected to one of the first inlet and the second inlet and outlet of the gasifier and supplying a gas material to the gasifier;
Control which controls the quantity of combustible gas discharged from the other of the 1st entrance and the 2nd entrance / exit of the gasification furnace by controlling the flow of the gaseous material which the capacity type blower supplies to the gasification furnace A gasifier system comprising: a part.

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