JP2006297195A - Regeneration treatment method of waste and its apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regeneration treatment method of the dismantled residues and minced residues of buildings or a mixture thereof, shredder dust, waste reclaimed in the past, waste which is illegally abandoned and the like, which intends to unify the components and then enables them to be recyclable by removing flammable matters included in the residues or waste products to detoxify them by calcination. <P>SOLUTION: The regeneration treatment method of waste comprises throwing the residue or waste into a front combustion chamber, evaporating the moisture by utilizing heat generated by the combustion of the flammable matters, throwing the incineration ash into a rotary kiln and blowing the high temperature combustion gas and agitated air in counter-current into the kiln while rotating the kiln. Thus, the flammable matters included in the incineration ash are burned and the noncombustible matter such as sand, rubble and ash are exposed to hot gas and calcined by circulation with agitation. The calcined sand, rubble and ash in the rotary kiln are sanitized to form the calcined material with high purity without containing flammable matters, and are discharged from the rotary kiln. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, no construction residue or minced dismantling residue generated after dismantling the building, a mixture thereof (hereinafter collectively referred to as “wastes such as construction residue”), and organic Shredder dust containing volatile or volatile matter, waste landfilled in the past at the final disposal site, waste left for a long time due to illegal dumping, etc. (hereinafter collectively referred to as “shredder dust” in the claims and claims) Recycled processing methods and equipment, especially waste materials such as waste, etc., especially by removing combustibles contained in the processed material and making the components of the discharged material uniform. The present invention relates to a processing method and apparatus.

  Conventionally, the construction residue generated after dismantling the construction has been landfilled in a managed disposal site. However, with the full enforcement of the Construction Recycling Law in 2002, mince dismantling was prohibited and segregation was obligatory. Here, the minced dismantling is the dismantling of the construction by heavy machinery and has the advantage that the cost of dismantling is low, but the dismantling is in the form of a mixture, so there is no choice but to landfill at the final disposal site.

  According to the survey in 2000, 77% of the construction demolition residue is concrete lumps and asphalt lumps, with 9% sludge and 6% timber. The remaining 8% is non-recyclable waste called construction mixed waste (usually called mince). Its properties include moisture, organic matter and metal content, which is similar to waste that has already been landfilled with soil, and may adversely affect the environment around the landfill, separating organic matter and metals from them, It is desired that the remaining earth and sand and debris be made harmless and recycled.

  For this sorting process, sieve sorting, wind sorting, magnetic sorting, etc. are used, but in order to sort construction residue and waste landfilled in the past by such means, large-scale equipment is required, There is a problem that the processing cost is high, and the construction residue and the earth and sand and rubble which occupy most of the waste landfilled in the past cannot be reused. In other words, in a situation where chronic landfill shortage has become a social problem, it is necessary to detoxify harmful waste, to reduce the amount of waste as much as possible, and to be able to reuse waste, Even if organic matter and metal are separated, the current treatment system in which earth and sand and rubble, which occupy most of the residue, is landfilled is not preferable.

  In addition, when processing illegally dumped waste that has become a social problem, they are left for a long period of time, so a great investment is required to separate and reuse them. Recycling is almost difficult. If such mixed waste can also be reused, it will not go beyond that, and it is desired to make it harmless and recycle it.

  In view of such a problem, the applicant of the present application, in Patent Document 1 below, puts construction residual soil into a rotary kiln, blows high temperature combustion gas counter-currently while rotating the kiln, and the high temperature combustion gas includes the residual soil in the residual soil. Construction waste soil that burns incombustible combustibles and conveys and removes fly ash with combustion gas flowing in the kiln, and burns incombustibles such as sand and rubble to obtain reusable waste with uniform components A reproduction processing method and a processing apparatus are proposed.

On the other hand, in Patent Document 2 below, in a cocurrent flow type rotary kiln, that is, a rotary kiln in which combustion gas flows in the same direction as the movement direction of the waste in the kiln, combustion air is supplied to the waste introduced into the kiln from the input chute. There has been proposed a technique for efficiently incinerating waste by providing an air nozzle cylinder to be blown and blowing combustion air on the waste immediately after being charged.
JP 2002-79234 A JP 2001-227720 A

  When there is relatively little moisture or organic content in the construction residual soil to be treated, waste can be treated efficiently by the method and apparatus proposed in Patent Document 1. However, as a result of treatment tests on various types of waste, waste such as construction residue has a high moisture content, and waste such as shredder dust that contains more organic and combustible matter than construction residual soil It is difficult to burn completely combustible materials at the site, resulting in problems such as poor processing efficiency, or organic matter such as oysters (burning wood, etc.) remains in the emissions and hinders reuse. There was found.

  This problem cannot be solved by means of supplying combustion air toward the waste immediately after being put into the kiln by a chute as described in Patent Document 2.

  Based on the above findings, the present invention completely burns and removes harmful or harmful organic or flammable materials from waste such as construction residues and shredder dust. It is an object to obtain a recycling treatment method and equipment for construction residue, etc. that discharges certain earth and sand, rubble, ash, metal, etc. as inorganic materials that can be easily separated and reused, with high processing efficiency and low processing costs. .

  In the invention of this application, waste such as construction residue and waste such as shredder dust are gradually transferred to a discharge port 15 provided on the opposite side of the input port by rotating the kiln 14, In a method for recycling waste such as construction residues, the combustion gas is blown countercurrently into the rotary kiln 14 to combust combustible organic components contained in the waste and to burn and discharge incombustible components. A pre-combustion chamber 7 that communicates with the kiln is provided on the waste input side and the combustion gas discharge side of the rotary kiln 14, and after the waste is temporarily retained in the pre-combustion chamber and pre-combusted, the rotary kiln 14 to solve the above problem.

  When the treated product is waste such as construction residue, the combustion gas of the air volume necessary for transporting and discharging fly ash generated during the combustion of organic components in the rotary kiln 14 by the gas flow in the kiln is used. Infuse. When the stirring air is blown into the kiln together with the combustion gas, the fly ash is conveyed and discharged by the air volume of both.

  For example, waste such as construction residues and shredder dust are continuously charged into the pre-combustion chamber 7 by the quantitative charging device 5, and the above-mentioned waste is disposed on the grate 8 and 10 installed in the pre-combustion chamber 7. For the wall of the precombustion chamber 7 and the stirring air, the water-cooled structure grate 12 is provided for burning the pyrolysis gas generated from combustible matter in the material and burning the firewood that takes time to burn. Oki on the Oki grate 12 is burned with air stirring by the combustion air introduced from the pipe. As for the burned oki, ash and inorganic matter discharged from the lower part of the oki combustion grate 12 are introduced into the kiln 14, and the waste is provided on the opposite side of the quantitative charging devices 5 and 6 by the rotation of the kiln 14. Gradually transfer to the outlet 15.

  Note that the combustion of the combustible portion in the pre-combustion chamber 7 does not need to be completely terminated, and may be introduced into the kiln 14 before the combustion is completed. Further, the combustion grate 8, 10 may be one stage or multistage.

  During the transfer of waste such as construction residues and waste such as shredder dust in the kiln 14, the high-temperature combustion gas flows countercurrently into the rotary kiln 14, that is, in the direction facing the transfer direction of the waste in the kiln. Infuse. This high-temperature combustion gas burns unburned carbon and other combustible components contained in the waste, and burns by exposing non-combustible materials such as sand, rubble, and ash to the high-temperature combustion gas.

  As a method for generating the high-temperature combustion gas, any method such as a method of directly releasing the burner flame into the kiln 14 or a method of releasing the hot air generated by installing a hot air generating furnace into the kiln may be used. When processing waste such as construction residues, the flow rate of high-temperature combustion gas and agitation air flowing in the rotary kiln 14 is transported by fly ash generated by combustion of organic components in the waste such as construction residues to be reclaimed. The air volume is as high as necessary.

  It is preferable to provide a stirring air blowing nozzle 22 on the exit side of the processed material of the kiln 14. The air jetted from the agitating air blowing nozzle 22 toward the treated product 38 is supplied with unburned material, in particular, unburned carbon combustion air, and the fine fired product is again moved to the intermediate part of the kiln. Contrary to the above, by carrying air and repeating firing, the fine fired product gradually increases in particle size, and approaches the appropriate size for recycling, generally the size of sand for construction.

  In this way, fine ash is not left in the fired product 38 discharged from the kiln 14, and a fired product with high purity and wide reuse can be obtained.

  The high-temperature combustion gas at 800 to 1000 ° C. discharged from the rotary kiln 14 is introduced into the precombustion chamber as it is and generally maintains its temperature. In order to prevent re-synthesis of dioxins (synthesized in the range of 250 to 450 ° C.), it is practically quenched with a temperature reducer (also called a gas cooling tower) 23 that cools the combustion gas with the latent heat of vaporization of the jet water. To do. The relatively large fly ash in the combustion gas is separated by gravity sedimentation in the temperature reducer 23, and the relatively fine one is separated by an advanced dust collector 24 such as a bag filter installed downstream of the temperature reducer or a multi-cyclone. Separate and collect.

  On the other hand, the earth and sand and debris fired by being exposed to high-temperature combustion gas in the rotary kiln 14 become a sterilized and high-quality fired product containing no combustible matter and discharged from the rotary kiln outlet 15. Therefore, the metal is separated by magnetic separation, and if necessary, the particle size is made uniform by sieving.

  The waste treatment apparatus according to the invention of this application used for the above-described regeneration treatment includes a rotary kiln 14, charging devices 5 and 6 that continuously or intermittently supply the processed material in the rotary kiln 14, and a combustible material. A pre-combustion chamber 7 for combustion, a combustion gas blowing device 16 for sending high-temperature heated air by combustion of gas or heavy oil into the rotary kiln in a countercurrent, and agitating air on the discharge side of the processed material from the rotary kiln 14 An agitating air blowing device 22 that blows into the rotary kiln with a flow; a temperature reducer 23 that rapidly cools the combustion gas discharged from the rotary kiln 14; and a dust collector 24 that removes ash from the exhaust gas that has passed through the temperature reducer 23. And a magnetic beneficiation machine 33 provided in the passage of the fired product discharged from the rotary kiln 14.

  When the waste such as construction residues is fired by the method of the present invention, the fine fired product of the fired product fired in the rotary kiln 14 is placed on the combustion gas and stirring air, and refired. Ashes are discharged so that fine baked products do not remain in the baked product as much as possible, that is, flammable products and unburned carbon by combustion are removed, and fine baked products generated by calcination are removed by wind beneficiation. The operations are carried out at the same time, and the reduction of the purity of the baked product caused by the remaining organic matter and its combustion ash and the resynthesis of harmful substances during the cooling process are avoided. Therefore, it is possible to obtain a high-purity fired product that can be reused as a construction site backfill, asphalt pavement, or a lightweight aggregate of concrete.

  In addition, when waste such as shredder dust is fired in the invention of this application, it contains a large amount of heat generated during combustion in the pre-combustion chamber and complete removal of combustibles remaining in the treated product By removing the moisture, the combustion gas and the fly ash transported to the combustion gas can realize a process in which no harmful substances are discharged by the exhaust gas process using the combination of the temperature reducer 23 and the dust collector 24 that has already been established.

  The present invention will be further described below with reference to the drawings. Wastes such as construction residues are transported to a processing plant by a dump truck 1 or the like and are input to the receiving pit 2. At this time, it is also possible to install the regeneration processing apparatus of the present invention in the same site as the existing processing equipment and connect it with a belt conveyor or the like. In that case, the receiving pits 2 may be added and stored temporarily in order to increase the work efficiency.

  Waste such as construction residues temporarily stored in the receiving pit 2 is transferred to the fixed amount input device 5 by the input crane 4, and the above-mentioned waste discharged from the fixed amount input device 5 by a fixed amount is input by the belt conveyor 3. It is transferred to the pusher 6. The waste is put into the precombustion chamber 7 in accordance with the operation status of the precombustion chamber 7. The thrown-in waste falls on the upper grate 8 and starts to burn, a part of pyrolysis gas is generated, and the combustible is gradually carbonized and incinerated. The waste burning in the upper grate 8 falls onto the lower grate 10 by pushing out the upper pusher 9. During the fall, the waste is mixed and burns more effectively. Further, the above-mentioned waste on the lower grate 10 which has been further burned falls onto the Oki combustion grate 12 having the same water cooling structure as the upper grate 8 and the lower grate 10 by pushing out the lower pusher 11. During the fall, the stale waste is mixed and burns more effectively. A water-cooled grate is effective in preventing the generation of clinker. The Oki combustion grate 12 includes an air supply port. The waste, which has been almost burned on the fire burning grate 12 whose oxygen concentration is adjusted by the combustion air supplied from the air supply port, is put into the rotary kiln 14 by the transfer pusher 13. The rotary kiln 14 is a rotary kiln inclined in a direction in which the side opposite to the throwing-in device is slightly lowered, and a discharge port 15 for the fired product is provided at the lower end on the side opposite the throwing-in device.

  The combustion gas of the burning burner 16 is guided to the discharge port side of the rotary kiln 14, and this high-temperature combustion gas passes through the rotary kiln 14 in the direction opposite to the transfer direction of the processed material, that is, from the discharge port 15 side. It flows to the material input side. Heavy oil in the heavy oil tank 17 is fed into the burning burner 16 by a heavy oil pump 18, and the heavy oil is burned by the air of the pushing fan 19 that sends combustion air, and the high-temperature combustion gas is blown into the rotary kiln 14. It is.

  Although a gun-type burner can be used as the firing burner, generally, a high-pressure spray burner is suitable. In this case, high-pressure air generated by a compressor is sprayed together with fuel.

  In the rotary kiln 14, the processed material sent from the fire burning grate 12 is scraped up and dropped along the furnace wall as the kiln rotates. At this time, the treated material is exposed to high-temperature combustion gas flowing in the kiln, earth and sand and rubble are fired, and organic matter such as plastic and wood contained in the construction residue that was not completely burned in the previous combustion chamber Burns into ash, of which particularly fine fly ash is carried by the combustion gas and flows to the pre-combustion chamber 7. A combustion auxiliary burner 21 is provided in the pre-combustion chamber so that combustible materials can be completely burned.

  On the discharge port 15 side of the rotary kiln 14, a stirring air blowing nozzle 22 is dragged by the rotation of the kiln indicated by an arrow in FIG. 4 with its tip slightly downward as shown in FIGS. It is provided so as to be biased so that air is directly injected toward the processing object 38 that is unevenly distributed downstream in the rotational direction of the kiln cylinder lower part. It is preferable that the stirring air blowing nozzle 22 has a heat-resistant structure such as water cooling. The stirring air generated by the stirring air blowing fan 20 is jetted by the stirring air blowing nozzle 22 toward the processing object at the lower part of the kiln cylinder, thereby stirring the processing object 38 and increasing the efficiency of firing. The fired product having a particle size that cannot be transferred to the front combustion chamber by the high-temperature combustion gas is returned to the upstream direction of the rotary kiln 14, that is, the front combustion chamber 7 side. By repeating this operation, the fine fired product becomes a fired product having a larger particle size, increasing the use of construction civil engineering materials.

  The combustion gas that has passed through the pre-combustion chamber 7 passes through the temperature reducer 23, further passes through the dust collector 24, and is discharged from the chimney 26 by the induction fan 25. In the temperature reducer 23, a water injection nozzle 28 is provided in a gas passage 27 having a relatively large cross-sectional area, and high-temperature combustion gas is converted into a dioxin recombination region by the latent heat of evaporation of water injected from the water injection nozzle. It cools rapidly so that a certain 250-450 degreeC may be passed. Among the fly ash in the combustion gas, a large one is separated by gravity settling in the temperature reducer 23 and transferred to the dust storage facility 29. The fly ash that has passed through the temperature reducer 23 is collected by the bag filter 24 and transferred to the dust storage facility 30. The bag filter 24 may be a multi-cyclone. In general, a slaked lime spraying device 31 that sprays a neutralizing agent such as slaked lime is mixed with exhaust gas before being put into the bag filter 24. The exhaust gas from which the solid matter has been removed by the bag filter 24 and from which the acid gas has been removed by the neutralizing agent is discharged from the induction fan 25 through the chimney to the atmosphere.

  The unburned residue in the processed material put into the rotary kiln 14 is baked in the rotary kiln 14, moves to the discharge side, and is discharged from the discharge port 15. In that case, a rotary cooler for cooling the fired product may be provided, and the product temperature may be lowered and discharged. A discharge conveyor 32 is disposed below the discharge port 15, and a magnetic beneficiation machine 33 is provided at an outlet portion of the discharge conveyor, and the metal in the discharged solid matter is separated and transferred to the metal scrap storage facility 34. The The fired product that has passed through the magnetic separator 33 is applied to a vibration sieve 37, and fine particles having a small particle size are separated and discharged. . The particle size of the discharged fired product 36 is preferably about 30 mm or less from the viewpoint of transportation and reuse. Since the fired product is fired at a high temperature close to 1000 ° C., there is no residual organic or inorganic combustible material, and the composition is relatively stable. A fired product is obtained. Moreover, the metal scraps selected by magnetic separation are further finely separated and reused as necessary.

  That is, in the apparatus of the illustrated embodiment, combustible components are combusted in the precombustion chamber 7 and wastes such as construction residues continuously put into the rotary kiln 14 are separated into relatively high-purity metal scraps and fired products. The organic matter and inorganic combustible matter in the waste are incinerated, and the fly ash generated by the combustion is separated and removed, and then released into the atmosphere. Therefore, according to the invention of this application, environmental destruction caused by organic waste such as construction residue can be prevented, and earth and sand and rubble occupying most of the residual soil can be reused as aggregate of asphalt or concrete. In addition, the metal content in the waste can be separated relatively easily, the amount of impurities mixed into the separated metal is small, and the synthesis and mixing of harmful substances in the exhaust gas is also possible. It can be effectively prevented.

  Although the above example shows processing of wastes such as construction residues, wastes such as shredder dust can also be processed in the same way using a similar device. The difference is that in the treatment of waste such as construction residues, the air flow rate of the high-temperature combustion gas and the ash produced by the combustion of combustibles in the residue are set so that the wind speed is necessary for discharging the ash together with the combustion gas as fly ash. While the air volume of the stirring air is set, in the waste such as shredder dust, since the combustible content is greatly different, the air volume of the high-temperature combustion gas is set so that the operation cost is the lowest. Is a point. Also in this case, the fired product obtained is burned and removed at a high temperature and burned and removed, resulting in a reduced granular material. Therefore, the fired product is highly safe and can be used as a construction material.

  Tables 1 to 3 show examples of the analysis results of the fired products obtained by firing the dismantling residue by the method of the present invention. Table 1 shows the results of measuring the content of elution of heavy metals from the waste collected from the landfill, Table 2 shows the results of measuring the content of elution of heavy metals from the fired material treated with the equipment of the present invention, and Table 3 shows the equipment of the present invention. It is a dioxin measurement result of the baked product processed by the above. As shown in each table, even when compared with the environmental standards for soil defined in the Basic Environmental Law, the standards are sufficiently cleared and safety is high.

Block diagram showing an embodiment Detailed view of the front combustion chamber and rotary kiln of FIG. Longitudinal sectional view showing the structure of the stirring air blowing part of the rotary kiln Cross-sectional view of the stirring air blowing part of the rotary kiln

Explanation of symbols

5 Fixed injection device 6 Input pusher 7 Front combustion chamber 8 Upper grate 9 Upper pusher
10 Lower grate
11 Lower pusher
12 firewood grate
13 Transfer pusher
14 rotating kiln
15 outlet
16 Burner for firing
22 Stirring air blowing nozzle
23 Temperature reducer
24 Dust collector
32 Discharge conveyor
33 Magnetic separator
35 Crusher
37 Vibrating sieve machine

Claims (6)

  Waste such as construction residue is continuously charged into the pre-combustion chamber by a fixed-quantity charging device, and after partially generating pyrolysis gas and partially combusting in the pre-combustion chamber, it is input into the rotary kiln and inside the rotary kiln. Is gradually transferred to a discharge port provided on the opposite side of the front combustion chamber, and the high-temperature combustion gas of the air volume that conveys the fine ash generated by the combustion of organic matter in the waste as fly ash in the rotary kiln The ash is transported and discharged by the combustion gas and burned by exposing the non-combustible waste to the combustion gas. Recycling method for waste such as construction residue.   Waste such as shredder dust is continuously thrown into the pre-combustion chamber by the fixed-quantity charging device, and after partially generating pyrolysis gas and burning in the pre-combustion chamber, it is continuously put into the kiln and the kiln is rotated. While gradually injecting the incinerated waste introduced into the discharge port provided on the opposite side of the previous combustion chamber, hot combusted gas is blown countercurrently into the rotary kiln to remove the combustible content contained in the waste. A method for recycling waste such as shredder dust, which is incinerated and fired and discharged by exposing non-combustible materials in the waste to the combustion gas.   By supplying air for stirring into the rotary kiln from the exit side of the fired product, and repeatedly firing the ash or fired product with a small particle size contained in the treated product in the rotary kiln back to the kiln or the pre-combustion chamber. The regeneration processing method according to claim 1 or 2, wherein the particle size of the ash or the fired product is increased.   A rotary kiln, a pre-combustion chamber for gasifying and combusting combustibles in a processed product connected to the processing material input side of the rotary kiln, and supplying the processed material to the pre-combustion chamber continuously or intermittently Counter-current supply device, transfer device that volatilizes volatile components in the pre-combustion chamber, generates pyrolysis gas, and transports the pre-combusted processed material into the rotary kiln, and counterflows high-temperature combustion gas generated by combustion of gas and heavy oil And a combustion gas blowing device for feeding into the rotary kiln, and the combustion gas is discharged through the precombustion chamber, and is a waste regenerating device for waste such as construction residue or shredder dust.   The pre-combustion chamber is equipped with a combustion grate and a fired fire grate. The fired fire grate has a dedicated combustion air supply port for burning hard-to-burn fire and water cooling to prevent clinker generation. The reproduction processing apparatus according to claim 4, further comprising: a structure.   The regeneration processing apparatus according to claim 4 or 5, further comprising a stirring air blowing device for supplying stirring air into the rotary kiln on the fired product outlet side.

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