JP2013083393A - Waste treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem wherein since a waste treatment apparatus including a rotary kiln used for incinerating or firing waste requires a large amount of surplus air, this lowers a temperature inside a furnace, causing decline in combustion efficiency and creates a shortage of combustion air, leading to discharge of unburned substances, and thus to provide a waste treatment apparatus capable of more completely incinerating or firing a larger variety of waste.SOLUTION: The waste treatment apparatus incinerates or fires waste by using heat of high-temperature gas flowing from one side to the other side within a rotary kiln. An auxiliary air nozzle having a tip inserted into the rotary kiln to blow combustion air in toward the waste within the kiln is installed on the outlet side of the high-temperature gas from the rotary kiln. In a preferable structure, a pre-combustion chamber is installed on the waste inflow side of the rotary kiln to continue to the kiln.

Description

  The present invention relates to a waste treatment apparatus used for incineration of waste or incineration of combustibles in waste and incombustion of incombustibles, and includes the above-described apparatus having a rotary kiln, particularly a rotary kiln and a precombustion chamber. The present invention relates to the above-mentioned apparatus particularly suitable for the apparatus.

  Patent Documents 1 and 2 show an incinerator for waste including a rotary kiln and a precombustion chamber. The pre-combustion chamber of Patent Document 1 does not include a grate and points out problems of the grate furnace, but the pre-combustion chamber of Patent Document 2 includes a single-stage grate. Further, Patent Documents 3 and 4 disclose waste treatment apparatuses including an air supply cylinder that supplies combustion air necessary for burning combustibles in a rotary kiln on the inflow side of a high-temperature gas. . FIG. 2 is a view showing a waste treatment apparatus proposed by the applicant of the present invention in Patent Document 3, in which the rotary kiln 14, the combustion gas blowing device 16 provided on the discharge outlet side of the rotary kiln 14, and the stirring are shown. An air blowing device 22, a precombustion chamber 7 connected to the processing material input side of the rotary kiln 14, a charging device 5 for continuously or intermittently supplying the processing material to the precombustion chamber 7, and a processing material This is a regeneration device for the construction residue, comprising a transfer device 13 for transferring the fuel from the front combustion chamber 7 into the rotary kiln 14. The precombustion chamber in the waste treatment apparatus described in Patent Document 3 is a stalker provided with multistage grates 8, 10, and 12.

  The hot gas is blown into the rotary kiln 14 by the combustion gas blowing device 16 by a method of directly releasing the burner flame into the kiln 14, a method of releasing the hot air generated in the hot air generating furnace, or the like. Further, the stirring air blowing device 22 that blows air into the rotary kiln has a processing object that is unevenly distributed downstream in the rotational direction of the kiln at the bottom of the cylinder of the rotary kiln 14 with the tip of the nozzle inserted into the rotary kiln slightly downward. It is provided so that air is directly injected toward

  The waste treatment apparatus proposed in Patent Document 3 will be further described with reference to FIG. 2. The high-temperature gas and the stirring air blown into the rotary kiln from the combustion gas blowing device 16 and the stirring air blowing device 22 are the rotational kiln 14. Along with countercurrent flow, that is, in the direction opposite to the moving direction of the processed material moving in the rotary kiln, with the combustion gas of the processed material burned in the rotary kiln 14 and the ash (fly ash) floating in the gas Then, it is discharged through the pre-combustion chamber 7 and discharged from the chimney through a temperature reducer and a dust collector (not shown).

  In the pre-combustion chamber 7, grate 8 and 10 and a grate 12 are installed. In the pre-combustion chamber 7, the pyrolysis gas generated by heating the processed material put on these grate from the charging device 5 is burned, and the fire that takes time for incineration is the water-cooled structure fire. On the lattice 12, the combustion is performed by the air of the pushing fan 19 b that feeds the combustion air dedicated to Oki provided in the front combustion chamber 7 and the combustion air contained in the high-temperature gas flowing in from the rotary kiln 14.

  The combustible component is gasified and combusted in the pre-combustion chamber 7, the volatile component is volatilized to generate pyrolysis gas, and the pre-combusted processed material is sent to the rotary kiln 14 by the transfer device 13. In the rotary kiln 14, the non-combustible material in the processed material that is agitated by the rotation of the rotary kiln 14 and moves to the discharge port side is baked by the high-temperature gas flowing countercurrently in the rotary kiln, and the combustible material is air in the high-temperature gas. The ash is transferred to the precombustion chamber 7 together with the combustion gas as fly ash. The fired product fired in the rotary kiln 14 is discharged from the discharge port of the rotary kiln 14, and is separated by a magnetic beneficiator or a sieve not shown.

  In FIG. 2, reference numerals 9 and 11 denote pushers for transferring the processed material on the grate 8 and 10 to the lower grate 10 and 12, 19 (19 a and 19 b) are pushing fans for stirring air, and 20 is a stirring An air pushing fan, 22 is a stirring air blowing nozzle, and 21 is a combustion auxiliary burner provided in the front combustion chamber 7.

  On the other hand, in Patent Document 4, in a co-current type rotary kiln, that is, a waste incinerator in which high-temperature gas flows in the same direction as the movement direction of the waste in the rotary kiln, the waste kiln was put into the rotary kiln. There has been proposed a technique for efficiently incinerating waste by providing an air nozzle cylinder for blowing combustion air to the waste and blowing the combustion air to the waste immediately after being charged. This waste incinerator is not provided with a pre-combustion chamber, and waste is put directly into the rotary kiln.

Japanese Utility Model Publication No. 5-61623 JP 2002-81631 A JP 2006-297195 A JP 2001-227720 A

  The apparatus proposed in Patent Document 3 is used not only for burning construction residues but also for incineration of waste with a small proportion of incombustibles. In such a situation, when processing waste with a high moisture content or waste containing a large amount of organic or combustible material, it is necessary to increase the amount of air blown from the stirring air blowing device when trying to perform complete combustion. A problem has been found in which the amount of air becomes larger than the amount of air necessary for the combustion of waste, and the gas temperature in the rotary kiln and the precombustion chamber is lowered to lower the incineration efficiency. In this case, if the amount of air from the stirring air blowing device is reduced, it becomes difficult to completely burn the waste, and there arises a problem that unburned matter is discharged from the rotary kiln. This problem is particularly noticeable when burning incinerated ash of industrial waste that contains a large amount of unburned waste as waste, or in the treatment of waste containing FRP.

  This problem is solved by means of supplying combustion air toward waste immediately after being put into the kiln by a chute, as described in Patent Document 4, as well as in the devices described in Patent Documents 1 and 2. I can't.

  The present invention has been made to solve the above-mentioned problems. The apparatus described in Patent Document 3 is improved, and a large amount of surplus air is required. Therefore, the temperature in the furnace is lowered and the combustion efficiency is reduced. To solve the problem of reducing the combustion temperature and the problem of exhausting unburned material due to insufficient combustion air for burning incombustible materials while maintaining the high temperature in the rotary kiln. An object of the present invention is to obtain a waste treatment apparatus capable of more completely incinerating or firing various types of waste.

  The waste treatment apparatus of the present invention is a waste treatment apparatus that incinerates or burns the waste in the rotary kiln 14 by the heat of the high-temperature gas flowing from one to the other in the rotary kiln 14. In the waste treatment apparatus of the present invention, an auxiliary air nozzle that inserts a tip 26 into the rotary kiln 14 on the outlet side of the hot gas from the rotary kiln 14 and blows combustion air toward the waste in the kiln. 25. That is, the auxiliary air nozzle 25 is provided on the opposite side of the combustion gas blowing device 16 provided on the high temperature gas inflow side to the rotary kiln 14.

  In order to fire non-combustible materials such as earth and sand and concrete debris, high-temperature gas should flow in the direction opposite to the direction of transport of the waste in the rotary kiln 14, and the combustible materials in the waste For complete combustion, the pre-combustion chamber 7 for drying, pyrolyzing or burning the waste sent to the rotary kiln 14, particularly preferably the pre-combustion chamber (stalker) having a multistage grate is used for the rotary kiln. 14 is preferably connected to the waste input side. The pre-combustion chamber 7 is provided with an input device 5 that inputs the waste into the pre-combustion chamber 7 and a transfer device 13 that sends the waste from the pre-combustion chamber 7 to the rotary kiln 14.

  The auxiliary air nozzle 25 inserts a tip 26 into the rotary kiln 14 from the side connected to the front combustion chamber 7 of the rotary kiln 14, and supplies air to the waste that has been transferred from the front combustion chamber 7 into the rotary kiln 14. The auxiliary air blown from the auxiliary air nozzle 25 is discharged through the precombustion chamber 7 together with the high-temperature gas flowing countercurrently in the rotary kiln 14. More preferably, a recombustion chamber 3 for reburning the exhaust gas is provided.

  In order to perform complete burning or incineration of waste, it is preferable to provide a stirring air blowing device 22 for stirring waste on the side together with the combustion gas blowing device 16 on the inflow side of the high temperature gas to the rotary kiln 14. In this case, the amount of air supplied from the auxiliary air nozzle 25 into the rotary kiln 14 is adjusted to ½ or less of the amount of air supplied from the stirring air blowing device 22, particularly preferably in the range of 1/8 to 1/3. Air amount adjusting means 28 is provided.

  By this invention, the problem which an unburned thing remains when incineration waste with much moisture content and combustible content, waste containing FRP, etc. with the apparatus proposed in patent documents 3 is solved, and the device of patent documents 3 is Since the present invention is particularly suitable for the firing treatment of waste containing a large amount of unburned matter, the present invention provides a waste treatment apparatus capable of more completely incinerating and firing a wide variety of types of waste. effective.

Block diagram showing an embodiment The same figure as FIG. 1 showing a conventional device

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a view showing an embodiment of the waste treatment apparatus of the present invention. Only parts different from the conventional apparatus shown in FIG. 2 will be described below.

  An auxiliary air nozzle 25 is provided at the connecting portion between the rotary kiln 14 and the front combustion chamber 7, that is, on the outlet side of the hot gas from the rotary kiln 14 with its tip 26 inserted into the rotary kiln 14. A pushing fan 27 for sending air to the air nozzle 25 and a damper 28 for adjusting the air amount are installed. The pushing fan 19a (see FIG. 2) for sending the combustion air onto the fire grate 12 from the opening provided on the wall surface of the front combustion chamber 7 in the conventional apparatus of FIG. 2 is not provided. The pre-combustion chamber 7 is only provided with an air inlet for forming a thin air film along the wall surface in order to prevent clinker from being generated on the wall surface.

  The auxiliary air nozzle 25 has a tip 26 which is transferred from the precombustion chamber 7 into the rotary kiln 14 by the transfer device 13 at a position immediately after the transfer of the processed product. Install in a position to blow air. The amount of air supplied from the auxiliary air nozzle 25 at the time of incineration or baking of waste is supplied into the rotary kiln 14 from the stirring air nozzle 22 provided on the opposite side of the rotary kiln 14 (processed product outlet side). It is less than 1/2 of the amount of air to be processed and varies depending on the type of waste to be treated (moisture content, combustible content, etc.). A good combustion state in the combustion chamber 7, that is, the temperature inside the furnace does not decrease due to excessive air, and a region where the combustion air is partially deficient occurs, and the unburned portion that has not been completely burned rotates. The inside of the furnace can be maintained in a state where it is not discharged from the kiln outlet 15.

  The hot gas and the stirring air from the combustion gas blowing device 16 and the stirring air blowing device 22 flow in the rotary kiln 14 in the direction opposite to the moving direction of the waste, and the auxiliary air blown from the auxiliary air nozzle 25 and the air. It flows into the precombustion chamber 7 from the rotary kiln 14 together with the combustion gas of the waste combusted by the above, and the combustion of the waste and the pyrolysis gas generated therefrom is caused by the air contained in these gases. And is discharged from the pre-combustion chamber 7. The high-temperature gas of 800 to 1000 ° C. discharged from the rotary kiln 14 is introduced into the pre-combustion chamber 7 as it is and generally maintains its temperature in the pre-combustion chamber 7.

  In the apparatus of the illustrated embodiment, the gas discharged from the pre-combustion chamber 7 is guided to the re-combustion chamber 3, and the gas passing through the re-combustion chamber 3 passes through a dust collector such as a temperature reducer and a bag filter from the chimney. Discharged. The temperature and components of the gas discharged from the precombustion chamber 7 are not uniform, and the gas temperature, the ratio of excess air, the ratio of unburned pyrolysis gas and fine combustibles, and the like change. Since the exhaust gas from the pre-combustion chamber 7 has a temperature sufficient to burn these pyrolysis gas and unburned fine combustibles, the exhaust gas is guided to the re-combustion chamber 3 and the re-combustion chamber 3 By stirring and mixing the inside, unburned matter and surplus air are brought into contact with each other so that no unburned matter remains in the exhaust gas guided to the temperature reducer.

  The waste treatment apparatus according to the present invention can be used for either incineration of waste containing almost no incombustible material, incineration of combustible matter in waste containing a large amount of earth or sand, concrete waste, etc., and firing of incombustible material. Can also be used. Complete combustion of combustible matter with less surplus air by appropriately adjusting the ratio of the amount of air supplied from the auxiliary air nozzle 25 and the amount of air supplied from the stirring air nozzle according to the moisture content and composition of the waste And firing of incombustible material. It is preferable to use a rotary kiln 14 having a length capable of firing non-combustible materials. However, if the rotary kiln 14 is an apparatus that only incinerates waste containing almost no non-combustible material, the rotary kiln 14 is used. The length of can also be shortened.

  The waste carried into the receiving pit of the processing plant is transferred to the quantitative charging device 5 by a crane or the like, and the waste discharged from the quantitative charging device 5 by a fixed amount is matched to the operation status of the pre-combustion chamber 7 in timing. The pre-combustion chamber 7 is charged by the charging pusher 6. 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 waste on the lower grate 10 which has been further burned falls onto the Oki combustion grate 12 having a water cooling structure similar to that of 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. The water-cooled grate is effective in preventing the generation of clinker.

  The waste that has almost been burned on the Oki combustion grate 12 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 counter-transfer device side is slightly lowered, and a discharge port 15 for a fired product is provided at the lower end of the counter-transfer device side.

  Combustion gas of the combustion 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 direction in which the workpiece is transferred, that is, from the discharge port 15 side. It flows to the input side. The heavy oil in the heavy oil tank is fed into the combustion burner 16 by a heavy oil pump, the heavy oil is burned by the air of the pushing fan 19 that sends the combustion air, and the high-temperature combustion gas is blown into the rotary kiln 14.

  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 product is exposed to high-temperature combustion gas flowing in the kiln, and the earth and sand and debris in the waste are fired. In addition, organic matter such as plastic and wood in the waste that has not been burned in the pre-combustion chamber is burned to become ash. Among them, particularly fine fly ash is transported 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.

  When unburned combustible matter is contained in the discharge from the discharge port 15 of the rotary kiln 14, combustion auxiliary air is blown into the rotary kiln 14 from the auxiliary air nozzle 25. The combustion auxiliary air is blown to the processed material that still has a large amount of combustible immediately after being transferred to the rotary kiln 14, and combustion is promoted in a high temperature environment by a high temperature gas flowing in the counterflow from the opposite side. The That is, a large amount of combustible component can be burned with a small amount of auxiliary air supplied on the outlet side of the high-temperature gas flowing through the rotary kiln 14, and the combustible component in the waste can be completely burned with a small amount of air as a whole. Is possible.

  The exhaust gas that has passed through the precombustion chamber 7 is guided to the recombustion chamber 3. In the recombustion chamber 3, the exhaust gas is agitated and mixed, and unburned substances floating in the low temperature region of the exhaust gas are mixed with the gas in the high temperature region and burned, so that the amount of dust in the exhaust gas is greatly reduced. The exhaust gas that has passed through the recombustion chamber 3 passes through a temperature reducer (not shown), further passes through a dust collector, and is discharged from the chimney by an attracting fan. In the temperature reducer, water is injected from a water injection nozzle into exhaust gas that passes through a gas passage having a relatively large cross-sectional area, and high-temperature exhaust gas is re-synthesized from dioxins at 250 to 450 ° C. by the latent heat of vaporization of water. Quench quickly to pass through. Large ones in the fly ash in the exhaust gas are separated by gravity settling in the temperature reducer. The fly ash that has passed through the temperature reducer is collected by a dust collector such as a bag filter or a multi-cyclone. The exhaust gas from which the solid matter has been removed by the dust collector and from which the acid gas has been removed by the neutralizing agent is released into the atmosphere through the chimney.

  At the time of incineration or calcination, an air volume of high-temperature gas composed of a mixed gas of air from the combustion burner 16 and the stirring air nozzle 22 is set according to the content of combustible matter in the waste, and blown from the auxiliary air nozzle 25 Adjust the amount of air generated. As a result, combustible components and harmful substances in the waste are burned and removed at a high temperature. When the waste contains incombustible materials such as earth and sand, concrete, metal, etc., these incombustible materials are discharged in the form of reduced granular particles with high purity.

3 Recombustion Chamber 5 Fixed Charger 6 Input Pusher 7 Precombustion 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
25 Auxiliary air nozzle
26 Tip of auxiliary air nozzle
27 Pushing fan
28 Air volume adjustment damper

Claims (5)

  In a waste treatment apparatus for supplying a high-temperature gas into a rotary kiln and incinerating or burning the waste in the kiln by the heat of the gas, the high-temperature gas from the rotary kiln that flows from one to the other in the kiln A waste treatment apparatus comprising an air nozzle on the outlet side, the tip of which is inserted into the kiln and blows combustion air into the waste in the kiln. A pre-combustion chamber provided in connection with the waste input side to the rotary kiln, an input device for introducing waste into the pre-combustion chamber, and a high temperature provided on the inflow side of the high-temperature gas to the rotary kiln In a waste treatment apparatus provided with a gas blowing device and a stirring air blowing device,
An auxiliary air nozzle having a tip inserted into the rotary kiln from the side connected to the front combustion chamber of the rotary kiln;
The air from the auxiliary air nozzle is directly blown to the waste that has been transferred from the precombustion chamber into the rotary kiln, and the precombustion chamber is mixed with the high-temperature gas and the stirring air that has flowed countercurrently through the rotary kiln. The waste disposal apparatus according to claim 1, which is discharged via   The waste treatment apparatus according to claim 2, further comprising a reburning chamber for reburning exhaust gas discharged through the precombustion chamber.   The air amount adjusting means for adjusting an air amount supplied from the auxiliary air nozzle into the rotary kiln to ½ or less of an air amount supplied from the stirring air blowing device is provided. Waste treatment equipment.   The amount of air supplied into the rotary kiln from the auxiliary air nozzle is adjusted by the air amount adjusting means in a range of 1/8 to 1/3 of the amount of air supplied from the stirring air blowing device. 4. The waste treatment apparatus according to 4.

Images