JP4235654B2 - Carbide manufacturing method and carbide manufacturing apparatus - Google Patents

Description

  The present invention relates to a carbide manufacturing method and a carbide manufacturing apparatus for processing a waste material to manufacture a highly safe carbide that does not cause ignition or fire.

Conventionally, when processing waste such as waste, in order to extend the life of the final disposal site (landfill), the amount of waste has been reduced by incineration, gasification and melting methods, and the like. On the other hand, recently, in response to a request for reduction of global warming gas (CO ₂ ), waste such as waste is not incinerated, but carbonized in a carbonization furnace and recovered as carbide to enable effective use. Has been proposed. This carbide can be used, for example, as an alternative material such as coal or coke as a fuel, or as a heat insulating material on the surface of a molten metal in a metal electric furnace, and thus is further effective for resource saving. In general, the carbide generated in the carbonization furnace is collected by a recovery device, and is subjected to a water washing treatment in a water washing tank in order to remove harmful substances such as chlorine contained in the carbide, and then subdivided into flexible containers and the like. Stored and transported.

On the other hand, this carbide contains many reactive groups such as free radicals and functional groups, and has a property of generating heat due to a low-temperature oxidation reaction or the like. Therefore, if the calorific value is larger than the amount of heat released from the carbide during storage and transportation in a flexible container, etc., the carbide accumulates heat, and this heat further promotes an exothermic reaction such as low-temperature oxidation of the carbide to a certain temperature. Exceeding may cause a thermal runaway and, in the worst case, could ignite and cause a fire.

The carbide recovered by the recovery device is at a high temperature (for example, 400 to 700 ° C.), contains many reactive groups as described above, and has exothermic properties such as a low-temperature oxidation reaction. Since the reaction such as low-temperature oxidation is suppressed by rapid cooling by the water washing treatment, the carbide is not yet stable when stored in a silo or stored in a flexible container or the like.

For this reason, in order to prevent the carbides being stored and transported in flexible containers, etc. from igniting or fire, the exothermic reaction such as low-temperature oxidation, which is the most reactive in the early stage, proceeds and becomes stable. It was necessary to store the carbide in a flexible container or the like for a certain period of time (for example, 150 hours), and to monitor the storage so as not to cause thermal runaway during storage. Accordingly, there has been a demand for the development of a new carbide production method for carbide that can be produced as a highly safe carbide by promoting exothermic reaction such as low-temperature oxidation during the production of carbide.

Moreover, in order to solve the said problem, the carbide | carbonized_material production | generation facility as shown to patent document 1 is proposed. This carbide generation facility is a facility that supplies at least one of an oxygen scavenger and a deoxygenated aqueous solution to the carbide and performs bagging in a state where the oxygen concentration in the bag is reduced by deaeration. However, in order to prevent heat generation of carbides by this method, there is a problem that large-scale equipment is required, and a running cost is increased because a deoxygenating agent and a deoxygenated aqueous solution are necessary.

Japanese Patent Laid-Open No. 2004-256122

  The present invention has been completed with the object of providing a carbide manufacturing method and a carbide manufacturing apparatus for manufacturing a highly safe carbide that does not cause ignition and fire by solving the above problems. Is.

In order to solve the above problems, the present invention is a sand layer maintained at 450 ° C. to 600 ° C. in a carbonization furnace whose interior is maintained at an air ratio of 1 or less, and pyrolyzes waste into carbide and pyrolysis gas. After that, the exothermic carbide separated and recovered by the recovery unit is supplied with a gas that can serve as an oxygen supply source provided between the recovery unit and the washing tank in the subsequent stage while maintaining a relatively high temperature. This is characterized in that it is guided into a stagnation device, and in this stagnation device, the carbide is brought into contact with a gas that can serve as an oxygen supply source to promote an exothermic reaction of the carbide, and then washed with water.

  In addition, it is preferable to accelerate the exothermic reaction of the carbide by heating the carbide.

  Also, shut off the supply of gas that can be an oxygen supply source such as air into the retention device, supply an inert gas into the retention device, supply at least one of water and water vapor to the carbide, It is preferable to promote an exothermic reaction such as a low-temperature oxidation reaction while preventing thermal runaway of the carbide by cooling any one or more.

  Further, based on at least one of temperature information and oxygen concentration information in the retention device, a supply amount of gas that can be an oxygen supply source such as air into the retention device, an inert gas supply amount in the retention device, and a heating amount of carbide It is preferable to control the exothermic reaction of the carbide by controlling one or two or more of the amount of water or steam supplied to the carbide and the cooling amount of the carbide.

On the other hand, the apparatus of the present invention, the waste, the following air ratio 1, and decomposing carbonization furnace carbide and pyrolysis gas sand kept at 450 ° C. to 600 ° C., the decomposed carbide in this carbonization furnace In a charcoal manufacturing apparatus equipped with a recovery device for separation / recovery and a washing tank for washing the carbide obtained by the recovery device, a gas that can serve as an oxygen supply source is supplied, and the carbide recovered by the recovery device is collected. A retention device that promotes an exothermic reaction by being brought into contact with the gas is provided between the recovery unit and the washing tank.

  The retention device includes any one of an inert gas supply device into the retention device, a heating device that heats the carbide, a supply device such as water vapor that supplies at least one of water and water vapor to the carbide, and a cooling device that cools the carbide. Or it is preferable that two or more are provided.

  Further, at least one of a temperature sensor and an oxygen concentration sensor is provided in the residence device, and the gas of the gas supply device is based on at least one of the temperature information obtained by the temperature sensor and the oxygen concentration information obtained by the oxygen concentration sensor. Control for controlling one or more of the supply amount, the inert gas supply amount in the staying device, the heating amount of the heating device, the supply amount of water and steam of the supply device such as water vapor, and the cooling amount of the cooling device An apparatus is preferably provided.

According to the carbide manufacturing method and carbide manufacturing apparatus of the present invention, waste is pyrolyzed into carbide and pyrolysis gas in a sand layer maintained at 450 ° C. to 600 ° C. in a carbonization furnace in which the inside is kept at an air ratio of 1 or less. After that, the exothermic carbide separated and recovered by the recovery device can be an oxygen supply source between the carbonization furnace and the subsequent washing tank while maintaining a relatively high temperature (for example, 400 to 700 ° C.). Because it was decided to carry out the water washing treatment after promoting the exothermic reaction such as low-temperature oxidation of carbides without causing thermal runaway in the staying device to which gas is supplied, in silos or flexible containers, etc. This saves the trouble of monitoring the carbides so that they do not run out of heat during storage, and makes it possible to produce carbides with low running costs and high safety without using large-scale equipment.

  In addition, based on at least one of temperature information and oxygen concentration information in the staying device, an air supply amount into the staying device, an inert gas supply amount such as nitrogen into the staying device, a heating amount of carbide, steam to the carbide, etc. Controlling exothermic reactions such as low-temperature oxidation of carbide by controlling either the supply amount or the cooling amount of carbide, or two or more, while preventing thermal runaway of carbide and efficiently and safely reducing the temperature of carbide An exothermic reaction such as oxidation can be promoted to produce a highly safe carbide.

  When the carbide production method of the present invention promotes the reaction from a state of high exothermic reactivity, such as relatively low-temperature oxidation, to a highly safe state, the combustible part of the carbide and the solid calorific value According to actual results, the rate of decline will be within 3%, and the product value as a fuel replacement product will not decline.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view of a carbide manufacturing apparatus showing an embodiment of the present invention. Reference numeral 1 denotes a carbonization furnace, which is a sand layer in which the air ratio in the carbonization furnace 1 is 1 or less and waste is kept at 450 ° C. to 600 ° C., and is pyrolyzed into carbide and pyrolysis gas. These carbides and pyrolysis gas are sent from the upper part of the carbonization furnace 1 to the collector 2 provided on the side of the carbonization furnace 1 and separated by the action of centrifugal force. This pyrolysis gas is released into the atmosphere after being burned in an incinerator. On the other hand, the carbides recovered by the recovery device 2 are transported to a water rinsing tank 3 for cleaning and removing harmful substances such as chlorine and are subjected to a water washing process. The carbide recovered by the recovery device 2 is, for example, 400 to 700 ° C., but when it is put into the washing tank 3, the carbide is rapidly cooled and a reaction such as low-temperature oxidation is suppressed. In view of this, the inventor of the present invention provides a staying device 4 that promotes an exothermic reaction such as low-temperature oxidation of the carbide recovered by the recovery device 2 in the preceding stage of the washing tank 3, and the low-temperature oxidation of the carbide in the staying device 4. After accelerating the exothermic reaction, etc., the water was washed in the water washing tank 3.

  This staying device 4 conveys the carbide recovered by the recovery device 2 to the washing tank 3 by a conveyor 5 as shown in FIG. Specific examples of the conveyor 5 include a belt conveyor, an apron conveyor, a bucket conveyor, a bread conveyor, a flight conveyor, a screw conveyor, a spiral conveyor, and a vibrating conveyor. In addition, the conveyor 5 may have a function of actively agitating the carbide being conveyed and bringing it into contact with a gas that can serve as an oxygen supply source such as air by using a connection.

  The carbide recovered by the recovery device 2 is guided into the retention device 4 while maintaining a relatively high temperature (for example, 400 to 700 ° C.). While being conveyed by the conveyor 5 provided inside the staying device 4, the carbide is brought into contact with a gas that can be an oxygen supply source such as air in the staying device 4 in a certain high temperature state (for example, 100 to 200 ° C.). An exothermic reaction such as oxidation is promoted. In order to sufficiently promote an exothermic reaction such as low-temperature oxidation of carbide, the residence time is preferably long (for example, 10 to 120 minutes). When the conveyor 5 is a screw conveyor or a spiral conveyor, or when the conveyor 5 has a function of applying vibration, the carbide is agitated during the conveyance, and further effective in promoting an exothermic reaction such as low-temperature oxidation. . Further, a space (not shown) in which carbides are temporarily retained may be provided in the middle of conveyance in the retention device 4, and an exothermic reaction such as low-temperature oxidation of the carbides may be promoted in this space.

When the carbide undergoes an exothermic reaction such as low-temperature oxidation in the staying device 4, oxygen in the staying device 4 is consumed, and an exothermic reaction such as low-temperature oxidation of the carbide is inhibited. Therefore, a gas supply device 6 such as a blower and a fan for supplying a gas which can be an oxygen supply source such as fresh air from the outside to the inside of the staying device 4 and promoting a low-temperature oxidation reaction of carbide is provided. Tei Ru. The gas supply device 6 supplies, for example, a gas that can serve as an oxygen supply source such as air into the staying device 4 from an air inlet 7 provided in a part of the staying device 4 in FIG. A gas that can serve as an oxygen supply source such as air supplied into the inside flows through the staying device 4 and is exhausted from an exhaust port 8 provided in a part of the staying device 4. Carbide entrained in the exhausted air or the like is collected by a dust collector (not shown) such as a bag filter and returned to the staying device 4.

  When the temperature inside the staying device 4 is lowered to, for example, 70 ° C. or less, an exothermic reaction such as low-temperature oxidation of carbides is hardly promoted. In the initial state where the carbonization furnace 1 and the staying device 4 are started, the temperature inside the staying device 4 may be low. Therefore, in order to heat the carbide and promote an exothermic reaction such as low-temperature oxidation of the carbide, the staying device 4 is preferably provided with a heating device 9. For example, the heating device 9 may generate heat by heating wire or the like provided in the staying device 4 to heat the carbide. However, the heating device 9 has a function of generating heat in the conveyor 5 itself, for example, heating the jacket portion of a jacket type conveyor. The carbide may be heated while the carbide is transported by the conveyor 5 with a function of circulating the medium, or the gas supply device 6 is provided with a heating device 9 to supply hot air into the staying device 4. The carbide may be heated.

  When the carbide generated in the carbonization furnace 1 reaches a certain temperature (for example, 250 ° C.), the thermal runaway occurs, the combustible component burns, the solid calorific value of the carbide decreases, and the energy value decreases significantly. . Therefore, in order to adjust the temperature inside the staying device 4 so that the carbide does not reach a certain temperature or to cool the carbide in an emergency where the carbide is likely to ignite, the staying device 4 has a cooling function. A device 10 is preferably provided.

  When the temperature in the staying device 4 exceeds 200 ° C., for example, the cooling device 10 is operated to cool the carbide and prevent the ignition of the carbide. For example, as shown in FIG. 1, the cooling device 10 is provided with a cooling pipe 11 in the staying device 4, and a cooling medium is circulated in the cooling pipe 11. The inside of the retention device 4 is cooled by the cooling medium flowing through the inside of the cooling pipe 11 to cool the carbide. The cooling medium flowing through the inside of the cooling pipe 11 is, for example, water, may be a liquid such as ethylene glycol or propylene glycol, or may be a gas such as air. Moreover, the cooling device 10 shall cool the conveyor 5, the carbide conveyed by the conveyor 5 may be cooled on the conveyor 5, or the carbide supplied by the air supply device 6 is cooled to cool the carbide. Alternatively, it may be cooled by spraying water from the supply device 12 such as water vapor into the staying device 4.

  Also, in the event of an emergency when the carbide ignites, a supply device 12 such as water vapor is supplied to cool the carbide by supplying at least one of water and wet steam to the carbide and taking away the heat of the carbide by the latent heat of vaporization of the water. It is preferable that the device 4 is provided.

  Similarly, an inert gas supply device 17 that supplies an inert gas such as nitrogen to reduce the oxygen concentration in the retention device 4 and stops the combustion of the carbide in an emergency when the carbide ignites is a retention device. 4 is preferably provided. The inert gas is not necessarily limited to liquid nitrogen, and may be an inert gas such as carbon dioxide, helium, neon, argon, krypton, or xenon.

  Exothermic reactions such as low-temperature oxidation must be efficiently performed without burning and igniting the carbide in the staying device 4. Therefore, the temperature sensor 13 and the oxygen concentration sensor 14 are provided in the staying device 4, and the conveyor is based on at least one of the temperature information measured from the temperature sensor 13 and the oxygen concentration information measured from the oxygen concentration sensor 14. 5, the air supply amount of the air supply device 6, the heat generation amount of the heating device 9, the cooling amount of the cooling device 10, the water or water vapor supply amount of the steam generator 12, the inert gas supply device 17. It is preferable that a control device 15 for controlling the gas supply amount is provided. A plurality of temperature sensors 13 may be provided in the retention device 4, and temperature information in the retention device 4 may be measured by the plurality of temperature sensors 13. Similarly, the oxygen concentration sensor 14 may be included in the retention device 4. A plurality of oxygen concentration sensors 14 may be provided to measure the oxygen concentration in the retention device 4.

  It is preferable to control the heating device 9 and the cooling device 10 by the control device 15 to control the temperature in the staying device 4 to, for example, 100 ° C. to 200 ° C. Further, it is preferable to control the gas supply device 6 by the control device 15 to control the oxygen concentration in the staying device 4 so that the carbide efficiently performs an exothermic reaction such as low-temperature oxidation and does not burn or ignite. . Further, the intake port 7 and the exhaust port 8 are provided with a shutoff valve 16 that shuts off the air into the staying device 4, and the control device 15 controls the shutoff valve 16 to control the oxygen concentration in the staying device 4. It is preferable.

  When the temperature measured by the temperature sensor 13 exceeds a specified threshold value (for example, 250 ° C.), the control device 15 determines that “the carbide is likely to burn and ignite”.

  Based on the above determination, the control device 15 controls the gas supply device 6 and the shutoff valve 16 to shut off the supply of gas that can be an oxygen supply source such as air into the staying device 4, thereby performing low-temperature oxidation of carbides, etc. Suppresses exothermic reaction and prevents combustion and ignition.

  Further, based on the above determination, the control device 15 controls the heating device 9 to stop the heating of the carbide to prevent an exothermic reaction such as low-temperature oxidation of the carbide from being promoted, and to prevent combustion and ignition.

  Further, based on the above determination, the control device 15 operates the cooling device 10, the water vapor supply device 12, and the inert gas supply device 17 to cool the carbide or reduce the oxygen concentration of the gas in contact with the carbide. Suppresses exothermic reactions such as low-temperature oxidation, preventing combustion and ignition.

  As another example, a rotary kiln (not shown) is provided in the staying device 4 instead of the conveyor 5, or a rotary kiln is provided in the staying device 4 together with the conveyor 5 to promote an exothermic reaction such as low-temperature oxidation of carbides. It is good. Here, the rotary kiln used in the present invention has a structure in which a cylinder (for example, a diameter of about 1 m) is placed on a roll having an inclination, and the cylinder rotates on the roll. When carbide is thrown into the cylinder, the cylinder rotates, and the carbide is continuously stirred while moving on the inclined surface in the cylinder. Therefore, it efficiently contacts with gas that can be an oxygen supply source such as air. Thus, an exothermic reaction such as low-temperature oxidation of the carbide is promoted.

  As described above, according to the present invention, without using a large-scale apparatus, it is possible to stabilize and quickly stabilize carbide having exothermic properties due to a low-temperature oxidation reaction or the like without deteriorating its value as a fuel substitute. In addition, it is possible to produce a highly safe carbide that does not cause ignition or fire due to thermal runaway of the carbide.

  Although the present invention has been described above in connection with the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. The carbide manufacturing method and the carbide manufacturing apparatus with such changes are also included in the technical scope without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Must be understood as.

It is explanatory drawing which shows embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carbonization furnace 2 Recovery device 3 Flushing tank 4 Retention device 5 Conveyor 6 Gas supply device 7 Suction port 8 Exhaust port 9 Heating device 10 Cooling device 11 Cooling pipe 12 Steam supply device 13 Temperature sensor 14 Oxygen concentration sensor 15 Control device 16 Shut off Valve 17 Inert gas supply device

Claims (9)

The waste is pyrolyzed into carbide and pyrolysis gas in a sand layer maintained at 450 ° C to 600 ° C in a carbonization furnace whose interior is maintained at an air ratio of 1 or less. While maintaining a relatively high temperature, the carbide having the lead is introduced into a retention device provided between the recovery unit and the washing tank in the subsequent stage, to which a gas that can serve as an oxygen supply source is supplied, and in this retention device, A method for producing carbide, comprising: bringing a carbide into contact with a gas that can serve as an oxygen supply source to promote an exothermic reaction of the carbide, followed by washing with water.   The method for producing carbide according to claim 1, wherein the carbide exothermic reaction is promoted by heating the carbide.   Either shut off the supply of gas that can be an oxygen supply source into the retention device, supply an inert gas into the retention device, supply at least one of water and water vapor to the carbide, or cool the carbide. Or by 2 or more, the exothermic reaction is promoted while preventing thermal runaway of the carbide, and the carbide production method according to claim 1 or 2.   Based on at least one of temperature information and oxygen concentration information in the retention device, supply amount of gas that can be an oxygen supply source in the retention device, supply amount of inert gas in retention device, heating amount of carbide, water to carbide The method for producing carbide according to any one of claims 1 to 3, wherein an exothermic reaction of the carbide is controlled by controlling any one or more of a steam supply amount and a cooling amount of the carbide.   The method for producing carbide according to any one of claims 1 to 4, wherein the exothermic reaction is a low-temperature oxidation reaction.   The carbide production method according to claim 1, wherein the gas that can serve as an oxygen supply source is air. Waste, with less air ratio 1, and decomposing carbonization furnace carbide and pyrolysis gas sand kept at 450 ° C. to 600 ° C., a collector for separating and recovering the degraded carbides in this carbonization furnace, In a charcoal manufacturing apparatus equipped with a water washing tank for washing the carbide obtained in this collector, a gas that can serve as an oxygen supply source is supplied, and the carbide recovered in the collector is brought into contact with the gas to generate an exothermic reaction. The carbide manufacturing apparatus characterized in that a retention device for promoting water is provided between the recovery unit and the washing tank.   The retention device includes any one of an inert gas supply device into the retention device, a heating device that heats the carbide, a supply device such as water vapor that supplies at least one of water and water vapor to the carbide, and a cooling device that cools the carbide. The carbide manufacturing apparatus according to claim 7, wherein the above is provided.   At least one of a temperature sensor and an oxygen concentration sensor is provided in the residence device, and the gas supply amount of the gas supply device is based on at least one of the temperature information obtained by the temperature sensor and the oxygen concentration information obtained by the oxygen concentration sensor. A control device for controlling one or more of the inert gas supply amount into the staying device, the heating amount of the heating device, the supply amount of water and steam of the supply device such as water vapor, and the cooling amount of the cooling device The carbide manufacturing apparatus according to claim 8, wherein the carbide manufacturing apparatus is provided.

Images