JP2013177474A - Device and method for carbonizing biomass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for carbonizing biomass to obtain a carbonized product in a high yield, by thermally decomposing the biomass.SOLUTION: In a device 10 for carbonizing biomass provided with a carbonization furnace for producing a carbonized product, by supplying the biomass from an upper part of a vertical type carbonization furnace 11, to form a biomass-packed moving bed in the carbonization furnace, by supplying high-temperature gas from a lower side of the carbonization furnace, and by bringing the biomass into contact with the high-temperature gas, to be decomposed thermally, the device 10 for carbonizing the biomass includes a temperature control device 16 for controlling the temperature of an inside of the carbonization furnace 11, and the temperature control device 16 is set to control the temperature of the packed moving bed upper part at a drying temperature for evaporating contained moisture of the biomass to be dried, or higher, and at a tar condensation temperature for condensing tar, or lower, and to control the temperature of the packed moving bed lower part at a tar volatilization temperature for decomposing thermally the biomass to vaporize the tar, or higher, and at a gas generation temperature for decomposing thermally the biomass to generate gas, or lower, in order to establish prescribed temperature ranges.

Description

  The present invention relates to a biomass carbonization apparatus and a biomass carbonization method that carbonize biomass to obtain a carbide.

  Attention has been focused on the effective use of biomass energy as a measure to prevent global warming. Biomass is a renewable, organic resource that is not a fossil resource. Biomass is a continuously renewable resource because it uses solar energy and is produced from water and carbon dioxide. Since biomass is an organic substance, carbon dioxide is emitted when it is burned. However, the carbon contained in this is derived from carbon dioxide absorbed from the atmosphere by photosynthesis during the growth process. Therefore, even if biomass is used, It may be considered that the amount of carbon dioxide is not increased. This property is called carbon neutral.

  In particular, among biomass, plant-derived biomass can effectively use carbon resources converted from carbon dioxide by photosynthesis during the plant growth process, and therefore does not lead to an increase in atmospheric carbon dioxide from the viewpoint of the life cycle of the resources. Biomass derived from plants is forestry (wood scrap, sawn wood waste, thinned wood, paper waste, etc.), agriculture (rice straw, straw, sugarcane straw, rice straw, grass, oil palm oil residue, etc.), waste (food waste) , Garden trees, building waste, sewage sludge, etc.).

  In recent years, development of gas fuel and carbide by pyrolyzing biomass has been studied. The use of carbides produced from biomass as an alternative to fuel and steelmaking coke is expected to reduce carbon dioxide emissions.

  In Patent Document 1, wastes such as municipal waste are pyrolyzed in an inert gas atmosphere using a vertical furnace to obtain carbide and pyrolysis gas, and the obtained carbide is used as an alternative fuel for coal and coke. And a technology for replacing carbon and activated carbon. The biomass can be pyrolyzed using the vertical furnace for thermal decomposition described in Patent Document 1 to obtain a carbide.

  In the thermal decomposition processing apparatus described in Patent Document 1, waste is put into a vertical furnace, a waste moving moving bed descending in the furnace is formed, and hot gas is added from the lower part of the furnace to the priority moving bed. The heated gas that rises against the waste that descends due to its own weight in the furnace is heated by countercurrent contact, and the waste is pyrolyzed to generate carbide and pyrolysis gas.

JP 2001-131557 A

  However, despite the current situation where it is desired to improve the carbide yield, which is the ratio of the generated carbide weight to the biomass raw material weight, the carbide yield is improved using the thermal decomposition treatment apparatus described in Patent Document 1. It has not yet been proposed to make it happen.

  This invention is made | formed in view of the above situations, Comprising: It aims at providing the biomass carbonization apparatus and biomass carbonization method which can thermally decompose biomass and can obtain a carbide | carbonized_material with a high yield. .

  As a result of diligent investigations to develop a process that enables pyrolysis of biomass to obtain a carbide in a high yield, the present inventors have obtained the following knowledge. That is, tar is produced when pyrolyzing biomass to produce carbide, and this tar is discharged from the carbonization furnace together with the generated gas, but it is further converted into carbide in the carbonization furnace without discharging the tar. In order to solve the above problems, the inventors have found a biomass carbonization apparatus and a biomass carbonization method capable of obtaining carbide in high yield, and completed the present invention. did.

  The biomass carbonization apparatus and the biomass carbonization method according to the present invention are configured as follows.

<Biomass carbonization equipment>
The biomass carbonization apparatus of the present invention supplies biomass from the upper part of a vertical carbonization furnace to form a packed moving bed of biomass in the carbonization furnace, supplies high temperature gas from the lower part of the carbonization furnace, and converts biomass into high temperature gas. In a biomass carbonization apparatus including a carbonization furnace that is brought into contact and thermally decomposed to generate carbide, the biomass carbonization apparatus has a temperature control device that controls the temperature in the carbonization furnace, and the temperature control device is a temperature above the packed moving bed. The temperature of the lower part of the packed moving bed is thermally decomposed by controlling the temperature below the drying temperature for evaporating the moisture contained in the biomass and drying it to a predetermined temperature range. It is characterized by being controlled within a predetermined temperature range by controlling the temperature to be equal to or higher than the tar volatilization temperature for volatilizing tar and lower than the gas generation temperature for generating gas by pyrolyzing biomass. There.

  In the present invention, it is preferable that the temperature control device controls the temperature of the upper part of the packed moving bed to 80 ° C. or higher and 100 ° C. or lower and the temperature of the lower part of the packed moving bed to 400 ° C. or higher and 700 ° C. or lower.

  Moreover, in this invention, it is preferable that a temperature control apparatus controls the temperature of the center height part of a filling moving bed to 200 to 400 degreeC.

  In the present invention, in order to perform the above-described control, the temperature control apparatus includes an upper temperature measuring unit that measures the temperature of the upper part of the packed moving bed, and a lower temperature measuring unit that measures the temperature of the lower part of the packed moving bed. Based on the temperature of the upper part of the packed moving bed and the temperature of the lower part of the packed moving bed, the biomass supply amount supplied to the carbonization furnace and the high-temperature gas supply amount supplied to the carbonization furnace are set so that these temperatures are within a predetermined temperature range. At least one of them can be controlled.

  Further, in the present invention, the biomass carbonization apparatus includes a partial combustion furnace that receives supply of combustible gas from a carbonization furnace and partially burns it to generate combustion gas, and the carbonization furnace using at least a part of the combustion gas as a high-temperature gas. It is possible to further include a hot gas supply means for supplying to the battery.

<Biomass carbonization method>
In the biomass carbonization method of the present invention, biomass is supplied from the upper part of the vertical carbonization furnace to form a packed moving bed of biomass in the carbonization furnace, high temperature gas is supplied from the lower part of the carbonization furnace, In the biomass carbonization method of contacting and pyrolyzing to produce carbide, the biomass is pyrolyzed at the bottom of the packed moving bed to volatilize tar, and the tar attached to the biomass descending from the top of the packed moving bed is volatilized, Maintain the temperature of the upper part of the packed moving bed and the lower part of the packed moving bed in the carbonization furnace within the specified temperature range so that the gaseous tar rising from the lower part of the packed moving bed is condensed and attached to the surface of the biomass. It is characterized by.

  In the present invention, it is preferable to control the temperature of the upper portion of the filling and moving bed to 80 ° C. or more and 100 ° C. or less and to control the temperature of the lower portion of the filling and moving bed to 400 ° C. or more and 700 ° C. or less to a predetermined temperature range.

  In the present invention, the temperature control of the filling moving bed is performed by measuring the temperature of the upper portion of the filling moving bed and the temperature of the lower portion of the filling moving bed, and based on the measured temperature of the upper portion of the filling moving bed and the temperature of the lower portion of the filling moving bed. This can be performed by controlling at least one of the biomass supply amount supplied to the carbonization furnace and the high-temperature gas supply amount supplied to the carbonization furnace so that the temperature falls within a predetermined temperature range.

  In the present invention, it is possible to receive a combustible gas from a carbonization furnace in a partial combustion furnace, partially burn it to generate combustion gas, and supply at least a part of the combustion gas to the carbonization furnace as a high-temperature gas. .

  According to such an apparatus and method of the present invention, the biomass supplied from the upper part of the carbonization furnace forms a packed moving bed in the carbonization furnace and comes into contact with the hot gas that is blown up from the lower part while descending by its own weight. Heated. Biomass is dried and preheated at the upper part of the packed moving bed, descends and is pyrolyzed at the lower part to produce carbides, which are discharged from the lower part of the carbonization furnace together with ash.

  In the lower part of the packed moving bed, the biomass is heated by the high-temperature gas and is pyrolyzed to generate carbide, tar and gas. The generated tar is conventionally discharged from the carbonization furnace together with the generated gas. However, according to the apparatus and method of the present invention, the tar is converted to carbide and the yield of carbide from biomass is improved. The principle of the process of converting this tar into carbide is described in detail as follows.

  (1) When biomass is heated by high-temperature gas in the lower part of the packed moving bed, it is pyrolyzed and gaseous tar volatilizes and rises. This gaseous tar rises to the top.

  (2) When reaching the upper part of the packed moving bed, the gaseous tar is cooled and condensed to become liquid tar and adhere to the surface of the biomass.

  (3) Biomass to which liquid tar has adhered falls.

  (4) The liquid tar adhering to the biomass is heated and vaporized by the high temperature gas at the lower part and rises again to the upper part.

  (5) By repeating the above (1) to (4), the tar adhering to the surface of the biomass is heated by the high-temperature gas in the process of tar rising and falling in the packed moving bed, and volatilization and condensation. Gradually, the thermal decomposition reaction and polymerization reaction of tar progress, and a part of tar is converted to carbide. The produced carbide is discharged further down the packed moving bed together with the carbide directly carbonized from the biomass. Conventionally, tar has been discharged to the outside of the carbonization furnace together with the gas generated in the carbonization furnace. However, in the present invention, since tar can be converted into carbide, the yield of carbide from biomass can be improved. Further, in the present invention, when tar is converted to carbide, a special catalyst is not used, a special reaction apparatus is not added, and at a relatively low temperature as compared with a tar carbide conversion reaction using a conventional catalyst. It can be carried out at a certain temperature of 700 ° C. or lower. Therefore, it is a process for converting tar that is economically excellent into carbide.

  Based on the biomass carbonization apparatus and the biomass carbonization method of the present invention, the biomass is controlled to have a temperature within a predetermined temperature range, the gaseous tar is volatilized from the biomass in the lower part of the packed moving bed, and this is condensed in the upper part. From a tar that is generated and produced by thermally decomposing biomass by converting the tar into a liquid tar, in the process of repeated volatilization and condensation, by promoting a thermal decomposition reaction and polymerization reaction of the tar and converting a part of the tar into a carbide. Since it was decided to obtain the carbide, the carbide can be obtained from the biomass with high yield.

It is the schematic which shows the structure of the whole biomass carbonization apparatus of this invention. It is a figure explaining reaction in the biomass carbonization apparatus of this invention. It is a figure explaining the temperature distribution in the filling moving bed carbonization furnace which concerns on this invention. It is a figure which shows the filling moving bed carbonization furnace of the biomass carbonization apparatus of this invention. It is a figure which shows the filling moving bed carbonization furnace of the biomass carbonization apparatus of this invention.

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

  In FIG. 1, the code | symbol 10 is a carbonization apparatus, and this carbonization apparatus 10 is the vertical combustion furnace 11, the biomass supply apparatus 12 which supplies biomass to this, and the partial combustion which carries out the partial combustion of the gas generated in a furnace A furnace 13 and a temperature control device 16 that adjusts these to control the temperature in the carbonization furnace 11 are provided.

  The carbonization furnace 11 is a vertical furnace, and is provided with a biomass supply port 11A and a generated gas discharge port 11B at the upper side, and a carbide discharge port 11C at the lower end, and is slightly above the carbide discharge port 11C. A hot gas inlet 11D is provided on the side.

  The biomass supply device 12 supplies biomass from the upper part or the upper side part of the carbonization furnace. A rotary valve or a screw feeder that cuts out biomass at a predetermined supply amount can be used.

  The biomass supply device 12 is connected to the biomass supply port 11 </ b> A of the carbonization furnace 11 and supplies biomass to the carbonization furnace 11 by a predetermined amount in accordance with a command from the temperature control device 16. In the carbonization furnace 11, a packed moving bed P of biomass is formed. This packed moving bed P forms a tar condensing region A at a low temperature upper portion and a tar volatilizing region B at a high temperature lower portion.

  The generated gas discharge port 11B in the upper part of the carbonization furnace 11 is connected to the partial combustion furnace 13 through an air supply device 14 such as a fan. The combustion gas generated in the partial combustion furnace 13 is discharged for processing in the next process, but a part of the combustion gas is sent to the hot gas inlet 11D at the lower part of the carbonization furnace 11 via the damper 15. ing.

  The carbonization furnace 11 is provided with an upper temperature measurement means 17A and a lower temperature measurement means 17B for measuring the temperature at the upper part and the lower part of the biomass filling moving bed P formed in the furnace. The temperature control device 16 receives signals from the upper temperature measurement means 17A and the lower temperature measurement means 17B, controls the biomass supply amount of the biomass supply device 12 based on the signals, and controls the hot gas supply amount. Therefore, the opening degree of the damper 15 is controlled.

  In the apparatus of the present embodiment configured as described above, in the carbonization furnace 11, the biomass is supplied from the upper biomass supply port 11 </ b> A by the biomass supply apparatus 12, the packed moving bed P is formed, and the partial combustion furnace 13. The high-temperature gas that is at least a part of the combustion gas generated in step 1 is supplied to the lower high-temperature gas inlet 11D. By contact with the high temperature gas that rises while biomass moves downward from the upper part to the lower part of the packed moving bed P, it is first dried and preheated at the upper part, further heated and pyrolyzed at the lower part, and carbide is generated along with ash from the bottom part. Discharged.

  Tar generated when the biomass is pyrolyzed becomes carbide in a process in the carbonization furnace 11 described later, and is discharged from the bottom carbide discharge port 11C. Further, the generated gas containing the combustible gas generated by the thermal decomposition is guided to the partial combustion furnace 13 by the air supply device 14 from the top generated gas discharge port 11B.

  In the pyrolysis and carbonization reaction of biomass in the carbonization furnace 11, gas is generated even under conditions that maximize the carbide yield. The main component of this generated gas is a combustible gas such as hydrogen, carbon monoxide, methane, etc., and has a calorific value as fuel, so this generated gas is sent to the partial combustion furnace 13 and air is supplied in this partial combustion furnace 13. It is desirable to use at least a part of the high-temperature combustion gas generated by partial combustion as a high-temperature gas supplied to the carbonization furnace 11.

  Hereinafter, the carbonization furnace used in FIG. 1, main apparatuses connected thereto, and the behavior of biomass in these will be described in detail.

<Carbonization furnace>
The furnace type of the carbonization furnace in the present invention is a vertical type furnace or a shaft type furnace, supplying biomass from the upper part or the lateral upper part of the carbonization furnace, forming a packed moving bed in the carbonization furnace, and the biomass from the upper part to the lower part Pyrolysis occurs during the downward movement, producing carbide.

  High temperature gas is supplied from the partial combustion furnace from the lower side or the lower side of the carbonization furnace, and the high temperature gas rises in the filling moving bed of the carbonization furnace. By circulating the hot gas through the packed moving bed, the hot gas is brought into contact with the descending biomass and heated. The supplied biomass is dried at the upper part of the packed moving bed to remove moisture, and in the process where the biomass descends from the upper part to the lower part of the packed moving bed, it is contacted with high-temperature gas and further heated and pyrolyzed to convert carbides, tar and gas. Generated.

  The carbide is discharged from a carbide discharge port provided at a lower portion or a lower side portion of the carbonization furnace. As the carbide discharging means, it is preferable to cut out the carbide using a screw feeder. The generated gas containing the combustible gas is discharged from the generated gas discharge port provided at the upper part or the upper side part of the carbonization furnace.

(Tar reaction in packed moving bed)
As shown in FIG. 2, biomass is heated by a high-temperature gas in a region below the packed moving bed in the carbonization furnace, and pyrolyzed to generate carbide, tar, and gas (referred to as “tar volatilization region”). Region indicated by B). Gaseous tar is volatilized in this tar volatilization region, the gas tar rises along with the high temperature gas and the generated gas, rises in the packed moving bed, is cooled in a relatively low temperature region above the packed moving layer, Tar condenses into liquid tar (referred to as “tar condensation region”, indicated by symbol A), and the liquid (mist) tar adheres to the surface of biomass in this tar condensation region. The biomass with tar attached descends in the packed moving bed. The lowered biomass is heated again in the tar volatilization region at the lower part of the packed moving bed, the tar is volatilized, the gaseous tar is accompanied by the high temperature gas and the generated gas, rises in the packed moving bed, and is carried to the tar condensing region. In this way, in the process where tar rises and falls in the packed moving bed and repeats volatilization and condensation, the tar adhering to the surface of the biomass is heated by the high-temperature gas, and the thermal decomposition reaction and polymerization reaction of tar progress gradually. Part of the tar is converted to carbide.

  The lower region of the packed moving bed as the tar volatilization region is preferably a region from a position about 10% above the height of the entire packed moving bed to a position about 40% above the bottom of the packed moving layer. Further, the upper region of the packed moving bed as the tar condensing region is preferably a region from the top of the packed moving layer to a position about 30% to 50% below the entire height of the packed moving layer.

(High temperature gas supply means)
The generated gas generated in the carbonization furnace is guided to the partial combustion furnace by an air supply device. The generated gas supplied to the partial combustion furnace is supplied with air and partially burned to generate combustion gas, and at least a part of the combustion gas is sent to the carbonization furnace as a high-temperature gas.

  A nozzle serving as a high temperature gas inlet 11D for blowing high temperature gas introduced from the partial combustion furnace is provided at the lower part or the lower side part of the carbonization furnace. It is preferable that a plurality of nozzles are provided and distributed in the circumferential direction.

  A duct for supplying at least part of the combustion gas discharged from the partial combustion furnace to the carbonization furnace as a high-temperature gas and a damper 15 for adjusting the supply amount are provided.

(Gas flow rate in the carbonization furnace)
The high-temperature gas supplied to the carbonization furnace rises in the packed moving bed together with the generated gas, but the gas flow rate at that time needs to be in an appropriate range. The gas flow rate is adjusted by adjusting the amount of hot gas supplied. If the gas flow rate is too large, the pressure loss of the gas passing through the packed bed is too large, so the load on the air supply device becomes too large, or the biomass particles are accompanied by the generated gas and discharged from the carbonization furnace, There arises a problem that the yield of carbide is lowered. Therefore, the high-temperature gas supply amount is adjusted so that the gas flow rate (linear velocity) is less than 0.5 Nm / sec. On the other hand, if the gas flow rate is too small, it becomes difficult to make the gas flow in the furnace uniform, so the high-temperature gas supply amount is adjusted so that the gas flow rate (linear velocity) is 0.02 Nm / sec or more.

(Carbonization furnace temperature)
The temperature of the packed moving bed in the carbonization furnace is adjusted to a preferable range by adjusting the conditions (temperature, supply amount) of the high-temperature gas to be supplied and the conditions (kind, supply amount) of the biomass to be supplied. In the present invention, the temperature of the packed moving bed refers to the total temperature of solid (biomass, carbide), gas (high temperature gas), and liquid (tar), which are constituent materials of the packed moving bed, A measured value measured by a temperature measuring instrument such as a thermocouple installed in the container may be used as the temperature of the packed moving bed.

  The temperature at the bottom of the packed moving bed is adjusted to 400 ° C. or higher and 700 ° C. or lower. When the temperature is lower than the lower limit (400 ° C.), tar volatilization does not proceed sufficiently, and carbonization of biomass does not proceed, resulting in a low carbide yield. Moreover, if the temperature is higher than the above upper limit (700 ° C.), the pyrolysis reaction of biomass becomes a reaction in which gas is generated frequently, and the yield of carbides is reduced. Is bulky. Most preferably, the temperature at the bottom of the packed moving bed is about 500 ° C.

  The temperature at the top of the packed moving bed is adjusted to 80 ° C. or higher and 100 ° C. or lower. When the temperature is lower than the lower limit (80 ° C.), the drying of the biomass does not proceed sufficiently and the moisture is not sufficiently discharged from the packed moving bed. Further, if the temperature is higher than the upper limit (100 ° C.), the condensation of tar is not sufficiently performed at the upper part of the packed moving bed, and the gaseous tar is discharged from the moving bed carbonization furnace together with the generated gas. Since it becomes low, it is not preferable.

(Preferred temperature distribution in packed moving bed)
In order to promote the reaction by increasing the respective range (height direction range) of the “tar condensation region” A and the “tar volatilization region” B, the temperature distribution in the packed moving bed is as described above. It is desirable to reduce the change in temperature within the range of the region of FIG. 3, and therefore, it is preferable that the temperature distribution in the packed moving bed carbonization furnace be as shown in FIG. The temperature distribution as shown in FIG. 3B does not meet the above conditions and is inappropriate. In order to make the temperature distribution in the filling moving bed carbonization furnace as shown in FIG. 3A, the temperature of the lower portion of the filling moving bed and the temperature of the upper portion of the filling moving bed are set within the above-described temperature range, and the filling moving bed It is preferable that the temperature of the central height portion of the glass be 200 ° C. or more and 400 ° C. or less.

  Temperature sensors are provided at appropriate positions above and below the filling moving bed so that the temperature of the filling moving bed in the carbonization furnace has a preferable temperature distribution as shown in FIG. It is more preferable to provide a plurality of temperature sensors in each of the upper part and the lower part because a preferable temperature distribution can be obtained more reliably.

<Temperature control device>
The temperature control device includes an upper temperature measuring means (temperature sensor) for measuring the temperature of the upper part of the filling moving bed, and a lower temperature measuring means (temperature sensor) for measuring the temperature of the lower part of the filling moving bed. Based on the temperature of the upper part and the temperature of the lower part of the packed moving bed, at least one of the biomass supply amount supplied to the carbonization furnace and the hot gas supply amount supplied to the carbonization furnace so that the upper temperature and the lower temperature are within a predetermined range To control.

  Control of the biomass supply amount is performed by adjusting the biomass cut-out amount by the biomass supply device, or by adjusting the number of rotations of a rotary valve used for biomass supply and the opening of a damper provided in the supply path.

  The control of the hot gas supply amount is performed by adjusting the opening of a damper provided in the hot gas supply line.

A detailed temperature control procedure will be described below.
-When the temperature of the upper part of the packed moving bed is lower than the predetermined range, at least one operation of decreasing the biomass supply amount and increasing the hot gas supply amount is performed.
-When the temperature of the upper part of the packed moving bed is higher than the predetermined range, at least one operation is performed among increasing the biomass supply amount and decreasing the high temperature gas supply amount.
When the temperature of the lower part of the packed moving bed is lower than the predetermined range, at least one operation is performed among decreasing the biomass supply amount and increasing the high temperature gas supply amount.
-When the temperature in the lower part of the packed moving bed is higher than the predetermined range, at least one operation is performed among increasing the biomass supply amount and decreasing the high temperature gas supply amount.

(Temperature control at the central height of the packed moving bed)
In order to promote the reaction by increasing the respective region ranges (height direction ranges) of the “tar condensation region” A and the “tar volatilization region” B in the packed moving bed, the temperature in the packed moving bed carbonization furnace The distribution is preferably as shown in FIG. For this purpose, the temperature of the lower part of the packed moving bed is set to 400 ° C. or higher and 700 ° C. or lower, the temperature of the upper part of the packed moving bed is set to 80 ° C. or higher and 100 ° C. or lower. It is preferable to set it to 400 ° C. or lower. The control of the central height portion of the packed moving bed and the temperature above the central height portion will be described in detail.

  A specific example of this temperature control will be described with reference to FIG. A temperature adjustment gas inlet 11E is provided at the central height portion of the filling moving bed of the carbonization furnace, the temperature adjusting gas is supplied to the center height portion of the filling moving bed, and the center height portion and the center height portion of the filling moving bed are supplied. Control the upper temperature. A temperature meter for measuring the temperature is provided in the middle of the packed moving bed, and the temperature is controlled by adjusting at least one of the component (oxygen concentration) and the supply amount of the temperature adjusting gas based on the measured value.

  When lowering the temperature above the center of the packed moving bed and the center height, supply oxygen-free or low-oxygen (1 vol% or less) low-temperature (eg, 200 ° C. or less) gas as the temperature adjustment gas. To do. As an oxygen-free or low-oxygen low-temperature gas, for example, a gas obtained by directing a generated gas generated in a carbonization furnace to a cooling tower and directly cooling it with water spray can be used.

  The following control method may be used as a control method different from the above when lowering the temperature of the filling moving bed central height part and the upper part of the central height part. As the temperature adjustment gas, a gas obtained by mixing tar with a low temperature gas having no oxygen or low oxygen concentration as described above may be supplied. By mixing the tar in the gas and supplying it into the packed moving bed, the tar can be converted into a carbide together with the temperature control, and the carbide yield can be improved. As an oxygen-free or low-oxygen low-temperature gas mixed with tar, for example, the generated gas generated in the carbonization furnace is led to the cooling tower and directly cooled by water spray, and separated and recovered from the generated gas discharged from the carbonization furnace. Mixed tars can be used.

  When raising the temperature above the packed moving bed central height part and the central height part, oxygen-free or low-oxygen concentration (1 vol% or less) high-temperature (for example, 500 to 1000 ° C.) gas is used as the temperature adjustment gas. Supply. As an oxygen-free or low-oxygen concentration high-temperature gas, for example, a generated gas containing a combustible gas generated in a carbonization furnace is guided to a partial combustion furnace, and air is supplied so that the air ratio becomes 1 or less with respect to the combustible gas. A part of high-temperature combustion gas of 500 to 1000 ° C. generated by partial combustion can be used.

  The following control method may be used as a control method different from the above when the temperature of the filling moving bed central height portion and the temperature above the central height portion is increased. A gas containing oxygen, such as air, is supplied as the temperature adjusting gas. A gas containing oxygen is supplied to the central height portion of the packed moving bed, the combustible gas in the furnace is burned, and the temperature of the central portion of the packed moving bed and the central height portion is raised by the combustion heat. When supplying a gas containing oxygen, the supply amount and the like are controlled so that the temperature above the central height of the packed moving bed does not exceed 300 ° C. When the temperature exceeds 300 ° C., the reaction in which the biomass and carbides in the packed moving bed burn and burn out becomes significant, and the carbide yield decreases, so this must be avoided.

  Furthermore, the temperature control of the central height portion of the filling moving bed can be performed under the form shown in FIG. This control will be described with reference to FIG.

  In FIG. 5, the carbide cooling area | region which cools the carbide | carbonized_material produced | generated to the lower part from the hot gas inlet is formed in the carbonization furnace of FIG. The gas in the furnace is extracted from the in-furnace gas discharge port 11F provided in the carbide cooling region, and the gas that has been led to the cooling tower and directly cooled by water spray is supplied to the carbide cooling region from the cooling gas inlet 11G provided in the carbide cooling region via the blower. Supply and cool carbide. The temperature of the cooling gas is preferably 200 ° C. or less, and more preferably 100 ° C. or less. A temperature adjustment gas inlet 11E is provided at the center height portion of the filling moving bed of the carbonization furnace, and a part of the cooling gas led from the cooling tower is supplied to the center height portion of the filling moving bed as the temperature adjustment gas. Control is made so that the temperature at the center height portion and the temperature above the center height portion are lowered.

(Atmosphere of carbonization furnace)
The oxygen concentration in the atmosphere in the carbonization furnace is preferably 1 vol% or less. If the oxygen concentration in the atmosphere is higher than 1 vol%, the biomass burns and is not pyrolyzed, resulting in a low carbide yield.

  It is preferable to set the height (layer height) of the filling moving bed of the carbonization furnace within a predetermined range. If the bed height is small, there is not enough area for the gaseous tar to condense in the upper part of the packed moving bed, so it blows out from the packed moving bed and is discharged from the carbonization furnace accompanied by the generated gas. It is appropriate to do. If the bed height is too large, the pressure loss of the gas passing through the packed moving bed will be too high, so it is appropriate to set the bed height to less than 8 m.

<Partial combustion furnace>
The generated gas containing the combustible gas generated in the carbonization furnace is guided to the partial combustion furnace, air is supplied so that the air ratio becomes 1 or less with respect to the combustible gas, and partial combustion is performed, resulting in a high temperature of 500 to 1000 ° C. At least part of the combustion gas is used as a high temperature gas supplied to the carbonization furnace. Here, the air ratio refers to the ratio of the actually supplied air amount to the theoretical air amount necessary for combustion of the combustible gas.

<Biomass>
As a biomass studied as a raw material for pyrolyzing to generate carbides, there are by-products generated when palm oil is collected from wood chips, rice husks and oil palm (palm palm). There are hundreds of small fruits with a diameter of several centimeters in the oil palm bunches. Empty fruit bunches (Empty Fruit Bunch, EFB), old oil palm trees (Trunk), and squeezed oil from the fruits (Palm) Kernel Shell (PKS) is produced as a by-product in large quantities, and the use of these oil palm biomass as carbide raw materials is being studied. As biomass, it is preferable to use wood chips, rice husks, oil palm empty fruit bunches (EFB), old oil palm trees (Trunk), and oil palm fruit squeezed (PKS).

<Preferred particle size of biomass>
It is preferable that the specific surface area, which is the ratio of the surface area per volume, is larger than a certain value as a characteristic of the biomass to which the condensed tar easily adheres. Here, the surface area is a geometric surface area, not a surface area including even micro-level irregularities measured by the BET method or the like, but a surface area calculated from numerical values obtained by measuring the shape of an object.

It is preferable that the specific surface area of the biomass is larger than a certain value because tar easily adheres to the surface of the biomass. Specifically, a biomass having a specific surface area (geometric surface area / geometric volume) larger than 0.5 mm ⁻¹ is preferable. For example, a large wooden block of about 50 × 100 mm is not suitable because the specific surface area is smaller than 0.15 mm ⁻¹ . PKS has a particle size of about 4 mm. The specific surface area is 2 mm ⁻¹ , and the EFB is fibrous, so the specific surface area is about 3 mm ⁻¹ , and each is a preferable specific surface area, which is suitable as the biomass used in the present invention.

<Relationship between carbonization furnace temperature and biomass moisture content>
In order to allow a tar condensation region having a temperature of about 80 to 100 ° C. to cause tar condensation to be performed on the upper part of the packed moving bed, it is preferable that the moisture content of the biomass is not less than a certain level. When the moisture content of the biomass is 10% by weight or more, the thermal energy of the high-temperature gas is appropriately used for removing moisture from the biomass in the upper part of the packed moving bed, and the upper part temperature is set to a temperature of about 80 to 100 ° C. This is preferable because it is possible. On the other hand, if the moisture content is too high, the thermal energy of the high-temperature gas is excessively used for drying the biomass, and the thermal energy for biomass pyrolysis and carbonization is insufficient, so the moisture content should be less than 50% by weight. It is preferable.

[Example]
The test was implemented using the biomass carbonization apparatus shown in FIG. The carbonization furnace has a vertical cylindrical shape with an inner diameter of 1 m, and the height of the packed moving bed is 5 m. Sugi fine granules (particle size of about 4 to 5 mm, geometric surface area / geometric volume of about 1.5 mm ⁻¹ , moisture content of 15% by weight) as biomass are supplied to the carbonization furnace at a supply rate of 10 kg / hour. The high temperature gas is supplied to the packed moving bed carbonization furnace at a supply rate of 0.2 Nm ³ / sec, the temperature of the upper part of the packed moving bed is adjusted to 80 ° C., the temperature of the lower part of the packed moving bed is adjusted to 500 ° C., and carbide is generated. did.

  The tar is volatilized at the lower part of the packed moving bed, the tar is condensed at the upper part of the packed moving bed, and the tar generated from the biomass can also be made into carbide, and the carbide yield is 37% by weight. Compared with this, the carbide yield was improved. The fixed carbon in the carbide was 78% by weight, and it was possible to obtain an excellent carbide in terms of quality.

[Comparative example]
Using the same biomass carbonization apparatus and biomass as in the example, the biomass supply amount is the same, the high temperature gas supply amount is adjusted, the temperature of the upper part of the packed moving bed is set to 250 ° C., and the temperature of the lower part of the packed moving bed is set to 500 ° C. Adjusted to produce carbides.

  Tar did not condense at the upper part of the packed moving bed and was discharged from the carbonization furnace as gaseous tar. The carbide yield was 29% by weight, which was a low yield.

10 Biomass carbonization equipment 11 Carbonization furnace 11D Hot gas supply means (hot gas inlet)
13 Partial combustion furnace 16 Temperature control device 17A Upper temperature measurement means 17B Lower temperature measurement means

Claims (9)

The biomass is supplied from the upper part of the vertical carbonization furnace to form a packed moving bed of biomass in the carbonization furnace, the high temperature gas is supplied from the lower part of the carbonization furnace, the biomass is brought into contact with the high temperature gas and pyrolyzed to produce the carbide. In a biomass carbonization apparatus including a carbonizing furnace to be generated,
The biomass carbonization device has a temperature control device that controls the temperature in the carbonization furnace,
The temperature control device controls the temperature of the upper portion of the packed moving bed to a predetermined temperature range by controlling the temperature above the drying temperature for evaporating the moisture contained in the biomass and drying it to below the tar condensation temperature for condensing tar. The biomass carbonization characterized in that the temperature of the lower part is controlled to be equal to or higher than a tar volatilization temperature at which biomass is pyrolyzed to volatilize tar and below a gas generation temperature at which biomass is pyrolyzed to generate gas to be within a predetermined temperature range. apparatus.   The biomass carbonization apparatus according to claim 1, wherein the temperature control device controls the temperature of the upper portion of the packed moving bed to 80 ° C or higher and 100 ° C or lower and controls the temperature of the lower portion of the packed moving bed to 400 ° C or higher and 700 ° C or lower. .   The biomass carbonization apparatus according to claim 2, wherein the temperature control device controls the temperature of the central height portion of the packed moving bed to 200 ° C or more and 400 ° C or less. The temperature control device
Upper temperature measuring means for measuring the temperature of the upper part of the packed moving bed,
A lower temperature measuring means for measuring the temperature of the lower part of the packed moving bed,
Based on the measured temperature of the upper part of the packed moving bed and the temperature of the lower part of the packed moving bed, the biomass supply amount to be supplied to the carbonization furnace and the high temperature gas supply amount to be supplied to the carbonization furnace so that these temperatures are within a predetermined temperature range. The biomass carbonization apparatus according to any one of claims 1 to 3, wherein at least one of them is controlled.   The biomass carbonization apparatus receives a combustible gas from a carbonization furnace, partially burns it to generate combustion gas, and a high-temperature gas supply that supplies at least a part of the combustion gas to the carbonization furnace as a high-temperature gas The biomass carbonization apparatus according to any one of claims 1 to 4, further comprising means. The biomass is supplied from the upper part of the vertical carbonization furnace to form a packed moving bed of biomass in the carbonization furnace, the high temperature gas is supplied from the lower part of the carbonization furnace, the biomass is brought into contact with the high temperature gas and pyrolyzed to produce the carbide. In the biomass carbonization method to be produced,
At the bottom of the packed moving bed, the biomass is pyrolyzed to volatilize tar, and the tar adhering to the biomass that has descended from the top of the packed moving bed is volatilized, and the gaseous tar that has risen from the bottom of the packed moving bed at the top of the packed moving bed The biomass carbonization method characterized by maintaining the temperature of the upper part of the filling moving bed and the lower part of the filling moving bed in the carbonization furnace within a predetermined temperature range so as to condense and adhere to the surface of the biomass.   The biomass carbonization according to claim 6, wherein the temperature of the upper part of the packed moving bed is controlled to 80 ° C. or higher and 100 ° C. or lower, and the temperature of the lower part of the packed moving bed is controlled to 400 ° C. or higher and 700 ° C. or lower. Method.   Measure the temperature of the upper part of the packed moving bed and the temperature of the lower part of the packed moving bed, and based on the measured temperature of the upper part of the packed moving bed and the temperature of the lower part of the packed moving bed, so that these temperatures are within a certain temperature range, The biomass carbonization method according to claim 6 or 7, wherein at least one of a biomass supply amount supplied to the carbonization furnace and a high-temperature gas supply amount supplied to the carbonization furnace is controlled.   6. A combustible gas supplied from a carbonization furnace in a partial combustion furnace is partially combusted to generate combustion gas, and at least a part of the combustion gas is supplied to the carbonization furnace as a high temperature gas. The biomass carbonization method according to any one of 8.

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