JP4014524B2 - Method for continuous carbonization of waste and its continuous carbonization processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and equipment for continuously carbonizing general waste such as garbage and industrial waste such as waste plastic.
[0002]
[Prior art]
Regarding the disposal of general waste such as garbage and industrial waste such as waste plastic, in recent years, environmental pollution countermeasures such as dioxins have been emphasized, and waste is gasified by heating without incineration and pyrolysis and pyrolysis. There is a method of separating into residues.
When waste is gasified, an externally heated rotary kiln or a fluidized or shaft type processing furnace is used.
When waste is processed by an externally heated rotary kiln, the dry distillation gas generated by heating can be used as a fuel for a secondary combustion chamber of a melting furnace or melting furnace exhaust gas, which is a subsequent process, and is efficient.
Carbide, which is a pyrolysis residue, is selectively removed from recyclable carbides such as metal, and then subjected to high-temperature combustion treatment in a melting furnace, whereby the carbide is further reduced in volume to form molten slag, and dioxin The occurrence of odors can also be reduced.
However, the melting furnace of the above equipment is very exhausted because the inside of the melting furnace is high temperature. Therefore, periodic repairs are necessary, and it is forced to shut down for several weeks per year. Since the waste generated every day is accumulated with the suspension during this period, it is desired to continuously treat the waste during this period. Therefore, there is a method of providing a plurality of melting furnaces, but this leads to an increase in equipment costs.
[0003]
In order to meet the above demand, a fluidized bed gasification furnace for pyrolyzing and gasifying combustible waste contained in various types of waste such as municipal waste and / or industrial waste using a fluid medium such as sand and the combustible A melting furnace that melts the solid content obtained by pyrolysis gasification, a heat recovery device that recovers heat using the hot gas obtained in the melting furnace, and an exhaust gas purification device that purifies the exhaust gas discharged from the device In the fluidized bed gasification and melting apparatus, the pyrolysis gas generated by pyrolyzing and gasifying the combustible waste containing the solid matter in the fluidized bed gasification furnace using a fluid medium in the pyrolysis gas combustion furnace. By using the combustion gas obtained from the combustion and exchanging heat with an independent superheater (or an independent air preheater), the combustion gas after the heat exchange is used as a fluidizing fluid for a fluidized medium in a fluidized bed gasifier. , Fluidized bed gasifier It operated in a state disconnected from the melting furnace and a heat recovery device. That is, it has been proposed to continue operation of the fluidized bed gasification furnace independently even when the operation of the subsequent melting furnace to the fluidized bed gasification furnace is stopped for maintenance or due to malfunction (for example, Patent Documents). 1).
[0004]
[Patent Document 1]
JP 11-118124 A (page 9, FIG. 2)
[0005]
[Problems to be solved by the invention]
However, in the prior art described in Patent Document 1, in addition to the system including the melting furnace and the heat recovery device, the pyrolysis gas combustion furnace of the pyrolysis gas, and the heat exchange medium is heat exchanged using the obtained combustion gas. This system employs a system that uses an independent superheater (or an independent air heater) and uses the combustion gas after heat exchange as the fluidizing fluid of the fluidized medium of the fluidized bed gasification furnace. The structure is complicated because it cannot be said. In addition, since the combustion gas after heat exchange is directly supplied to the fluidized bed gasification furnace as a fluidized fluid, the combustion gas has a low oxygen concentration, reducing the partial combustion of combustible waste, and the temperature of the fluidized medium. There is a problem that it is difficult to maintain and therefore lacks the stability of pyrolysis gasification of a fluidized bed gasifier.
[0006]
Therefore, the present invention comprises a combination of an externally heated rotary carbonization furnace and a subsequent melting furnace, and the carbonization furnace can be continuously operated even if the melting furnace is shut down despite a relatively simple structure. In addition, an object is to achieve stable operation.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention heats and carbonizes general waste such as garbage and industrial waste such as waste plastic in an externally heated rotary carbonization furnace in a low oxygen atmosphere, It is stored in the stock tank, the carbide of the stock tank and the combustible gas generated by the carbonization are supplied to the melting furnace, burned and melted, and the combustion gas is processed in the secondary combustion chamber, the heat exchanger and the exhaust gas treatment device, In the continuous carbonization treatment method for waste, in which the heating air of the heat exchanger is supplied to the external heating rotary carbonization furnace, when the repair of the melting furnace is stopped, the combustibility of the external heating rotary carbonization furnace The property gas is sent to the secondary combustion chamber for combustion treatment, heat is exchanged by the combustion gas in the heat exchanger, and the heat source of the external heating rotary carbonization furnace is secured by the heat exchanged heat. Closed circuit It is formed. This circuit has a relatively simple structure and can be operated stably.
[0008]
Furthermore, the stock tank is a carbide whose volume has been greatly reduced by adopting a configuration in which the carbide from the external heating type rotary carbonization furnace accompanying the repair stop of the melting furnace is stored in the stock tank. In combination with this, the space for the waste pit is greatly reduced and the space is saved.
Further, by adopting a configuration in which the carbide from the external heating rotary carbonization furnace accompanying the repair stop of the melting furnace is cleaned and dehydrated, the carbide becomes a harmless carbonized fuel.
[0009]
General-purpose waste such as garbage and industrial waste such as waste plastic are heated in a low-oxygen atmosphere and carbonized by heating, a melting furnace that burns and melts the above-mentioned combustible gas, and the above A secondary combustion chamber for treating the combustion gas of the melting furnace, a heat exchanger and an exhaust gas treatment device, a stock tank for storing the carbide by the carbonization, a conveying means for supplying the carbide in the stock tank to the melting furnace, and the above A conduit for supplying the heating air of the heat exchanger to the carbonization furnace, and the combustible gas of the external heating rotary carbonization furnace when the melting furnace is stopped while operating the external heating rotary carbonization furnace And a conduit for supplying the secondary combustion chamber. As a result, even when the melting furnace is stopped for repairs, etc., the external heating type rotation can be performed by operating the secondary combustion chamber and the heat exchanger without providing another series of independent superheaters (or independent air preheaters). Because the type carbonization furnace can be operated, it becomes compact.
Moreover, the structure of the said stock tank of the magnitude | size which stores the carbide | carbonized_material from the said external heating type rotary carbonization furnace accompanying the repair stop of the said melting furnace is employable.
Moreover, the structure of the washing | cleaning and dehydration machine which wash | cleans and spin-dry | dehydrates the carbide | carbonized_material from the said external heating type rotary carbonization furnace accompanying the repair stop of the said melting furnace can be employ | adopted.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic flow of a continuous carbonization treatment facility for waste according to an embodiment of the present invention. In this flow, industrial waste such as general waste and waste plastic is crushed from a pit (not shown) by a crane or the like. It is put into the machine 1 and crushed to about 10 to 15 cm, and then put into a dryer which is a pretreatment device 2 and dried, and then put into an external heating rotary carbonization furnace 3 through a quantitative feeder 3a. The combustibles in the waste put into the external heating type rotary carbonization furnace 3 are in a low oxygen state, that is, about 400 to 500 ° C. in a substantially oxygen-free atmosphere having an air-fuel ratio of about 0.3 with the outside air shut off. Due to the external heating, it is pyrolyzed and carbonized with partial combustion. By this pyrolysis, combustible gas and carbide are generated, and the combustible gas is sent to the melting furnace 4 through the conduit a together with dust.
On the other hand, solids such as carbides, metals, and non-combustible materials in the external heating type rotary carbonization furnace 3 are discharged by the discharge device 3b, and then cooled to about 250 ° C. by, for example, water cooling means, and then separated by the separation device 10 It is separated into resources, incombustibles and carbides. The separated carbides are temporarily stored in the stock tank 11 and then quantitatively cut out by a quantitative cutout device (not shown) below the stock tank 11 and supplied to the melting furnace 4 by a conveying means 12 such as a belt conveyor.
[0011]
The carbide supplied to the melting furnace 4, the separately supplied combustible gas, and the auxiliary fuel supplied as necessary burn, and become high temperature (about 1250 to 1450 ° C.) due to the combustion of the high calorie carbide. Thus, the ash generated with combustion is melted to form slag, and the molten slag is cooled with water in a water-cooled tank (not shown) and recovered as granulated slag.
The combustion gas of the melting furnace 4 enters the secondary combustion chamber 5 from the conduit b, is guided to the temperature reducing tower 6 via the conduit c, and is lowered to a predetermined temperature, and then is guided to the heat exchanger 7 via the conduit d. After being used for heat exchange of air, the exhaust gas is introduced into the exhaust gas treatment device (bag filter) 8 through the conduit e and purified, and the purified exhaust gas is discharged from the exhaust tube 9 into the atmosphere through the conduit f. The
The heated air (hot air) heat-exchanged by the heat exchanger 7 is supplied to the externally heated rotary carbonization furnace 3 through the conduit g and used as a heat source for carbonization.
Further, when the melting furnace 4 is repaired and stopped, the combustible gas from the carbonization furnace 3 is branched from the conduit a and supplied to the secondary combustion chamber 5 through the conduit b for combustion treatment, and the heat exchanger uses the combustion gas. By supplying the heated air heat-exchanged in 7 to the external heating rotary carbonization furnace 3 through the conduit g, the continuous operation of the external heating rotary carbonization furnace 3 is possible even when the repair of the melting furnace 4 is stopped. Become.
A part of the heated air may be branched from the conduit g and supplied to the melting furnace 4 to be used as a heat source for increasing the combustion gas temperature. In addition, heated air (hot air) can also be used as a heat source for hot water supply and air conditioning.
[0012]
Further, a part of the combustion gas is supplied to the dryer 2 through a conduit h branched from the conduit b, and the waste is used as a heat source for drying to a predetermined moisture content. Then, it is charged into the melting furnace 4. By using the combustion gas as the heat source of the dryer 2, the thermal energy can be effectively used and the running cost can be reduced.
[0013]
In addition, when burning the combustible gas in the melting furnace 4, even if the quantity and properties of the combustible gas generated in the external heating type rotary carbonization furnace 3 are not constant, high calorific value carbide is supplied to the melting furnace 4. Therefore, stable high-temperature combustion is possible. As a result, the temperature of the combustion gas, and hence the temperature of the heated air by the heat exchanger 7, is also constant, and the control of the heating temperature of the external heating type rotary carbonization furnace 3 is extremely stable.
[0014]
By using an externally heated rotary kiln as the externally heated rotary carbonization furnace 3, combustibles are carbonized by indirect heating from the outside of the rotary kiln and partial combustion in the kiln, but a wide range of garbage, that is, general waste In addition to dealing with large fluctuations in waste quality when processing industrial waste together, it is easier to control the heating temperature to make the properties of the carbide constant compared to conventional fluidized bed gasification and melting furnaces. It is. By taking the residence time of garbage in the rotary kiln to about 1 hour, fluctuations in the generation of combustible gas can be suppressed. In addition, by supplying heated air from the heat exchanger 7 to a jacket (not shown) provided outside the rotary kiln and indirectly heating the kiln, temperature control in the kiln is facilitated and stable carbonization is performed.
[0015]
Combustible gas is combusted at high temperature in the melting furnace 4 (or the secondary combustion chamber 5) together with carbide of high calorific value, and the combustion gas is treated together with the introduction of chemicals in the exhaust gas treatment device 8, thereby controlling the generation of dioxins. It can be reduced to 1 ng-TEO / m ³ N or less.
[0016]
In the above embodiment, general waste such as garbage and industrial waste such as waste plastic are heated and carbonized in the external heating rotary carbonization furnace 3 in a low oxygen atmosphere, and the carbonized carbon is stored in the stock tank 11. Then, the carbide in the stock tank 11 and the combustible gas generated by carbonization are supplied to the melting furnace 4 to be burned and melted, and the combustion gas is processed in the secondary combustion chamber 5, the heat exchanger 7 and the exhaust gas treatment device 8 to exchange heat When the heating air of the vessel 7 is supplied to the external heating rotary carbonization furnace 3 and the repair of the melting furnace 4 is stopped while operating the external heating rotary carbonization furnace 3, the combustibility of the external heating rotary carbonization furnace 3 is reached. Although the property gas is burned in the secondary combustion chamber 5 and the heated air heat-exchanged by the heat exchanger 7 by the combustion gas is supplied to the externally heated rotary carbonization furnace 3, the melting furnace 4 is repaired. The carbide of the externally heated rotary carbonization furnace 3 accompanying the stoppage is increased. It can be made to the reservoir to the stock tank 11. Even if the repair stop period of the melting furnace 4 is several weeks per year, the capacity of the stock tank 11 is made large enough to store the carbide during the repair stop of the melting furnace 4. Since the carbide reduced to about / 4 is stored, it is much smaller and smaller than a large space pit for storing garbage.
In addition, the carbide in the external heating type rotary carbonization furnace 3 accompanying the repair stop of the melting furnace 4 can be cleaned and dehydrated by the cleaning / dehydrating machine 13. As a result, even when a series of melting furnaces are stopped for maintenance, carbide can be produced by operating the secondary combustion chamber 5, and the produced carbide is washed and dehydrated to produce harmless carbonized fuel. Become. In other words, the chlorine concentration is 0.5% or less and the heavy metal is clean below the soil environmental standard, and the calorific value is 30% higher than that of RDF (garbage solidified fuel) and has a high calorific value and high added value. Therefore, it is possible to effectively use the equipment and the equipment other than the equipment. In this case, the capacity of the stock tank 11 may be very small because the entire amount of carbide produced during the repair of the melting furnace is stopped and supplied to the washing / dehydrating machine 13.
[0017]
In addition, it reduces dioxins and other environmental pollution at a lower cost, leading to highly efficient energy recovery and energy use reduction. In addition, the on-time can be separately used when the carbide is required.
In the above embodiment, the dryer 14 may be added after the washing / dehydrating machine 13.
Further, by using the waste water of the waste water treatment device 15 that treats various waste water generated from this facility as the cooling water of the temperature reducing tower 6, the waste water is not discharged to the outside.
[0018]
Furthermore, in another embodiment, a part of the carbide in the stock tank 11 is supplied to the melting furnace 4 and the remaining part is supplied to the cleaning / dehydrating machine 13. A part of the carbide produced in the rotary rotary carbonization furnace 3 can be stored in the stock tank 11. Thus, even when a series of melting furnaces are stopped for maintenance, the remaining carbide can be produced by operating the secondary combustion chamber 5, and the produced carbide is washed by the washing / dehydrating machine 13.・ Dehydrated to become harmless carbonized fuel. Further, the capacity of the stock tank 11 in this case may be large enough to store a part of the carbide produced during the melting furnace repair stop.
[0019]
In another embodiment, a part of the carbide in the stock tank 11 is supplied to the melting furnace 4 and the remaining part is supplied to the cleaning / dehydrating machine 13. The entire amount of carbide produced in the rotary rotary carbonization furnace 3 can be supplied to the washing / dehydrating machine 13 via the stock tank 11 to be washed and dehydrated. Thereby, even when a series of melting furnaces are stopped for maintenance, carbide can be produced by operating the secondary combustion chamber 5, and the produced carbide is washed and dehydrated by a washing and dehydrating machine. It becomes harmless carbonized fuel. Further, the capacity of the stock tank 11 in this case may be extremely small since the entire amount of carbide produced during the melting furnace repair stop is supplied to the washing / dehydrating machine 13.
In the above description, the amount of carbide supplied to the melting furnace 4 is a part of the minimum amount necessary for obtaining heated air while maintaining high temperature for combustion of combustible gas and melting slag. However, the amount can be increased and used as a heat source for hot water or heating.
[0020]
【The invention's effect】
As described above, when the melting furnace is stopped for repair or the like as described above, the combustible gas of the externally heated rotary carbonization furnace is combusted in the secondary combustion chamber, and the combustion gas is used in the heat exchanger. Heat-exchanged heated air is supplied to the external heating rotary carbonization furnace so that the external heating rotary carbonization furnace can be operated continuously even when the melting furnace is stopped, and the structure is simple. In addition, more stable operation is possible.
[Brief description of the drawings]
FIG. 1 is a flow diagram of a continuous carbonization treatment facility for waste according to an embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Crusher 2 Pretreatment device 3 Carbonization furnace 4 Melting furnace 5 Secondary combustion chamber 6 Temperature reducing tower 7 Heat exchanger 8 Exhaust gas treatment device 9 Exhaust tube 10 Sorting machine (sorter)
11 Stock tank 12 Conveying means 13 Washing / dehydrating machine 14 Drying machine 15 Waste water treatment device

Claims (6)

General waste such as garbage and industrial waste such as waste plastic are heated and carbonized in an externally heated rotary carbonization furnace 3 in a low oxygen atmosphere, and the carbonized carbon is stored in the stock tank 11 and stored in the stock tank 11. Carbide and combustible gas from the carbonization are supplied to the melting furnace 4 to be burned and melted, and the combustion gas is treated in the secondary combustion chamber 5, the heat exchanger 7 and the exhaust gas treatment device 8, and the heat exchanger 7 In the continuous carbonization treatment method for waste, in which heated air is supplied to the external heating rotary carbonization furnace 3, when the melting furnace 4 is repaired and stopped, the combustible gas of the external heating rotary carbonization furnace 3 is used. Is sent to the secondary combustion chamber 5 for combustion treatment, and the heated air heat-exchanged by the heat exchanger 7 by the combustion gas is supplied to the external heating rotary carbonization furnace 3 to supply the external heating rotary carbonization. The furnace 3 was operated Continuous carbonization treatment method of waste characterized. The waste carbonization method according to claim 1, wherein the carbide from the external heating type rotary carbonization furnace 3 accompanying the repair stop of the melting furnace 4 is stored in the stock tank. The method for continuous carbonization of waste according to claim 1 or 2, wherein the carbide in the externally heated rotary carbonization furnace 3 accompanying the repair stop of the melting furnace 4 is cleaned and dehydrated. An external heating rotary carbonization furnace 3 for heating and carbonizing general waste such as garbage and industrial waste such as waste plastic in a low oxygen atmosphere, and a melting furnace 4 for combusting and melting combustible gas by the carbonization The secondary combustion chamber 5 for processing the combustion gas of the melting furnace 4, the heat exchanger 7 and the exhaust gas processing device 8, the stock tank 11 for storing the carbonized carbide, and the carbide in the stock tank 11 for the melting furnace 4, a conveying means 12 for supplying the heated air from the heat exchanger 7 to the carbonization furnace 3, and the combustibility of the external heating rotary carbonization furnace 3 when the melting furnace 4 is stopped. A conduit a for supplying gas to the secondary combustion chamber 5 and a continuous carbonization treatment facility for waste. The waste continuous carbonization facility according to claim 4, comprising the stock tank 11 having a size for storing the carbide from the external heating rotary carbonization furnace 3 when the repair of the melting furnace 4 is stopped. The waste carbonization treatment facility according to claim 4 or 5, comprising a cleaning / dehydrating machine 13 for cleaning / dehydrating the carbide from the external heating rotary carbonization furnace 3 when the repair of the melting furnace 4 is stopped. .

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