JP4197289B2 - Ash processing equipment - Google Patents

Description

  The present invention relates to a treatment apparatus for ash melting furnace exhaust gas.

  Conventionally, dust and incineration ash such as sewage sludge, municipal waste, and industrial waste are melted in an ash melting furnace by gas, oil, electric energy, etc. in order to recycle, reduce and detoxify them as slag and metal It has been taken out. When the slag is cooled and solidified, the volume is greatly reduced and the glass is vitrified, so that the heavy metals are enclosed and stabilized. For this reason, harmful substances do not elute into rainwater and groundwater, so there is no concern about secondary pollution caused by landfill. It can also be recycled into concrete aggregates and blocks for road tiles.

  On the other hand, since the exhaust gas generated during the melting process in the ash melting furnace contains fly ash (mainly NaCl, KCl), dioxin, heavy metals, etc., it must be rendered harmless by the exhaust gas processing apparatus. This will be described with reference to FIG. The gas generated in the melting furnace 3 is guided to an exhaust gas treatment device, and combustion of unburned carbon monoxide gas and hydrogen gas in the exhaust gas and decomposition of dioxin are performed in the secondary combustion chamber 29. The exhaust gas that has passed through the secondary combustion chamber 29 is guided to the temperature reducing tower 30, and water or air is introduced into the temperature reducing tower 30 to prevent dioxin resynthesis, and the exhaust gas temperature is cooled to about 200 ° C. The cooled exhaust gas is sent to a dust removing device 15 to remove dust, and then sent to a denitration device and a desulfurization device.

  However, in the above-described conventional exhaust gas treatment device, fly ash contained in the exhaust gas adheres and accumulates in the exhaust gas treatment device, causing internal clogging. In particular, it tends to adhere and accumulate in the vicinity of the tap and the bent part such as the second duct 31. In order to remove this deposit, a cleaning device 32 is installed in the exhaust gas treatment device. The cleaning device 32 is a device that blows air from the outside of the duct to remove deposits, and strikes a mass object against the duct surface with an electromagnetic coil or air force to remove the deposits by impacting them. There is a device installed on the surface of the duct outside, and a device installed on the surface of the duct that removes internal deposits by turning a motor with an eccentric weight to give vibration. These devices exfoliate and remove the fly ash accumulated inside, and the removed deposit falls in the tower. A hopper 28 and a deposit discharge device 14 are installed at the lower part of the temperature reducing tower 30 to collect the deposit and discharge it outside the exhaust gas treatment device. On the other hand, on the secondary combustion chamber 29 side, deposits fall directly into the cooling water tank 7 and contaminate the cooling water. Contamination of the cooling water in the cooling water tank causes slag and metal contamination. FIG. 5 shows a conventional technique for preventing contamination of the cooling water in the cooling water tank. A hopper 28 and a deposit discharge device 14 are also arranged below the secondary combustion chamber 29 so that the removed deposit does not fall directly into the cooling water tank 7.

  Patent Document 1 discloses a recombustion / cooling tower that integrally has a reburning function and a cooling function. As shown in FIG. 1 of this document, the recombustion / cooling tower has a second cooling zone in the upper part, and a recombustion / first cooling zone is arranged below it. Such an exhaust gas treatment device sprays water above the recombustion zone, so that water falls into the recombustion zone, cooled exhaust gas falls into the recombustion zone again, or the exhaust gas temperature during recombustion decreases. Cause. That is, when fly ash adheres to the water spray nozzle, normal water spray cannot be performed, and water particles fall into the recombustion zone. In addition, the exhaust gas that is warmed up in the recombustion zone and that is going to rise and the exhaust gas that is cooled in the cooling zone and that is going down are flowing in the direction of colliding with each other, causing the exhaust gas to stay. Such interference between the exhaust gas in the recombustion zone and the cooling zone and a drop in the cooling water cause a problem that a temperature range suitable for resynthesis of dioxin spreads inside the recombustion / cooling tower.

Japanese Patent Laid-Open No. 10-253041

  The present invention has been made in view of such circumstances, and its purpose is to prevent the accumulation of fly ash in the exhaust gas treatment apparatus as much as possible, facilitate the removal of the accumulated fly ash, slag, metal and cooling water thereof. It is to provide an ash treatment facility having an exhaust gas treatment device that realizes prevention of contamination, suppression of dioxin decomposition and resynthesis, and simplification of the exhaust gas treatment device.

In order to achieve the above object, an invention according to claim 1 is an ash treatment comprising an ash melting furnace, and an exhaust gas treatment device comprising a secondary combustion part for treating the exhaust gas from the ash melting furnace and a temperature reducing part. in equipment, the reduced temperature portion is arranged below the secondary combustion unit Rutotomoni, communicated via the tapping opening duct tapping port provided in the ash melting furnace, the slag by the cooling water water砕水granulated nozzle cover in which the nozzles are installed is provided for crushing cooling, Rukoto such communicating by the duct having no horizontal plane and the upper portion of the upper of Domizu砕nozzle cover secondary combustion unit It is characterized by.

  According to a second aspect of the present invention, in the ash treatment facility according to the first aspect, the secondary combustion section is provided below the tap outlet.

  According to a third aspect of the present invention, in the ash treatment facility according to the first or second aspect, the secondary combustion section and the temperature reducing section are integrally provided.

  According to a fourth aspect of the present invention, in the ash treatment facility according to the first or second aspect, the exhaust gas treatment device is provided with a deposit discharge device only below the temperature reducing portion. To do.

  According to a fifth aspect of the present invention, in the ash treatment facility according to the third aspect, the secondary combustion section and the temperature reducing section are formed of a cylinder built substantially vertically.

  A sixth aspect of the present invention is the ash treatment facility according to the fourth aspect, wherein the deposit discharging device includes a crushing unit and a transfer unit.

  From the configuration of the above invention, the following effects can be obtained in the present invention.

According to the first aspect of the invention, deposits such as fly ash generated in the secondary combustion section and fly ash in the exhaust gas, fly ash generated in the temperature reducing section, and fly ash in the exhaust gas can be collected in one place. In addition, it is possible to realize a temperature distribution that prevents interference between exhaust gases in the secondary combustion section and the temperature reduction section and prevents re-synthesis of dioxins and adhesion of fly ash.
In addition, the duct that connects the ash melting furnace and the secondary combustion section can be installed without raising the ash melting furnace upward, not only when the secondary combustion section is below the taphole, but also at the top. The exhaust gas can be extracted without providing the furnace with an exhaust gas extraction port. Therefore, it is not necessary to provide a hole for the exhaust gas outlet in the in-furnace refractory material of the ash melting furnace, which increases the durability of the refractory material. Further, since the duct does not have a horizontal plane, it is possible to prevent fly ash from accumulating and closing the duct.

  According to the second aspect of the present invention, it is not necessary to raise the first duct for guiding the exhaust gas from the ash melting furnace toward the secondary combustion section, the duct is bent less than before, and the fly ash adheres to the bent portion. , Can reduce deposition.

  According to the third aspect of the present invention, a duct connecting the secondary combustion section and the temperature reducing section is not required, and there is no possibility that fly ash adheres and accumulates in the duct and becomes blocked. Further, a cleaning device that removes fly ash adhering to and accumulating on the duct becomes unnecessary.

  According to the fourth aspect of the present invention, it is not necessary to provide a deposit carry-out device below the secondary combustion section, and deposits generated in the secondary combustion section and the temperature reduction section by the deposit carry-out apparatus provided in the temperature reduction section. Can be discharged.

  According to the fifth aspect of the present invention, the accumulated fly ash deposits generated in the secondary combustion section, the exhaust ash as well as the deposited fly ash generated in the temperature reducing section fall within the same cylinder and are collected in one place. Can do. Further, it is not necessary to separately install the secondary combustion chamber and the temperature reducing tower as in the prior art, and the equipment installation area can be saved.

  According to the invention described in claim 6, a large lump deposit can be crushed and carried out.

  Hereinafter, the present invention will be described in detail with reference to the best mode for carrying out the invention shown in the drawings.

  A first embodiment of the present invention is shown in FIG. The ash treatment facility of the present embodiment includes at least an ash melting furnace 3, a secondary combustion unit 10 and a temperature reduction unit 11 for treating exhaust gas, a dust removing device 15, and the like. The exhaust gas treatment device includes at least the secondary combustion unit 10 and the temperature reduction unit 11, and can include a series of devices from the tap port duct 22 to the exhaust gas fan 17.

The input ash storage tank 1 is connected to an ash melting furnace 3 via an ash quantitative supply device 2. The ash melting furnace 3 is connected to the secondary combustion unit 10 by the first duct 23. The first duct is provided with a tap outlet burner 4 in the vicinity of the tap outlet and a secondary combustion burner 5 in the vicinity of the secondary combustion section inlet. A secondary combustion section inlet temperature measuring device 24 is also installed. A temperature reducing unit 11 is installed below the secondary combustion unit 10. The cooling unit 11 is provided with a cooling water nozzle 12 above the temperature reducing unit and a cooling air nozzle 13 below the temperature reducing unit. A hopper 28 is provided below the temperature reducing unit 11. The sediment discharge device 14 is installed at the lower part of the hopper 28. The lower part of the temperature reducing unit and the dust removing device 15 are connected by a third duct 33. An ash discharging device 16 is installed at the lower part of the dust removing device 15. A fourth duct 34 is connected from behind the dust removing device 15 and communicates with the exhaust gas fan 17. In the figure, the dashed line indicates the slag discharge path, and the broken line indicates the flow path of the exhaust gas.

  The granulated water nozzle 6 is installed in the granulated nozzle cover 35 branched downward from the first duct 23, and the cooling water tank 7 is placed further below. The slag discharge conveyor 8 is installed so that a part of the slag discharge conveyor 8 is immersed in the cooling water so that slag and metal can be carried out from the cooling water tank 7. One end is led to a slag pit or a metal pit 9.

  Here, the first duct 23 is a duct that communicates the ash melting furnace 3 and the secondary combustion unit 10, the second duct 31 is a duct that communicates the secondary combustion chamber 29 and the temperature reducing tower 30, and the third duct 33 is A duct that communicates the temperature reducing section 11 and the dust removing device 15, and a fourth duct 34 refers to a duct that communicates the dust removing device 15 and the exhaust gas fan 17.

  The input ash storage tank 1 stores incineration ash and fly ash generated from the incinerator. The ash quantitative supply device 2 has a role of supplying a certain amount of ash to the ash melting furnace 3 by driving a screw conveyor. The ash charged into the ash melting furnace 3 is melted. The melting process varies depending on the type of the ash melting furnace 3. In the plasma ash melting furnace, a plasma generating gas (inert gas such as nitrogen gas or argon gas) is supplied to the plasma torch, and a voltage is applied to create a high-temperature, high-speed plasma state of 2000 to 10000 ° C or higher. Melt the ash. The inside of the ash melting furnace is covered with a refractory material and can withstand high temperatures. The embodiment of the present invention is not limited to the plasma ash melting furnace, but can be applied to an arc ash melting furnace, a resistance ash melting furnace, and the like.

In the ash melting furnace 3, ash is melted and separated as slag in the upper layer and metal in the lower layer.
The slag is continuously discharged from the outlet 20 at a temperature of 1400 ° C. or higher. Here, FIG. 2 shows an enlarged view of the vicinity of the tapper 20 and the tapper 21 of FIG. The tap outlet 20 is an opening provided in the lower portion of the side wall of the ash melting furnace 3 for discharging slag and metal. From the taphole 20, the taphole 21 extends downward, and slag and metal in the ash melting furnace pass through the taphole 20 and the taphole 21 and fall into the cooling water tank 7. In the present embodiment, the ash melting furnace 3 feeds the metal accumulated at the bottom of the furnace by tilting from the spout 20. The tilting means that the tilting device 18 tilts the ash melting furnace 3 with the tilting shaft 19 as the center of rotation.

  An output port 21 is provided on the output 21 so as to cover the output. The tap outlet duct 22 is inserted into the first duct 23 without a gap, and has a shape of drawing an arc. Due to the shape of the tap outlet duct 22, even when tilted, no gap is formed between the tap outlet duct 22 and the first duct 23, and the tilt can be tilted, leading to the exhaust gas treatment device without getting exhaust gas. . By removing the exhaust gas from the tap outlet 20, it is not necessary to provide a separate exhaust gas outlet in the ash melting furnace. Therefore, it is not necessary to make a hole in the refractory material of the ash melting furnace, which is convenient for maintaining the refractory material. The embodiment of the present invention is not limited to taking out the exhaust gas from the outlet, but can also be applied to an ash treatment facility in which an exhaust gas outlet is provided in a furnace lid or the like to treat the exhaust gas.

  In the present embodiment, the secondary combustion unit 10 of the exhaust gas treatment device is provided below the tap outlet 20, and the exhaust gas generated in the ash melting furnace 3 is guided to the exhaust gas treatment device at the tip of the tap 21. The exhaust gas contains carbon monoxide gas, chlorides such as sodium and potassium, and heavy metals such as zinc, cadmium, lead and arsenic. The exhaust gas treatment apparatus is provided with a secondary combustion unit 10 and a temperature reduction unit 11 disposed below the secondary combustion unit. After the exhaust gas exits from the outlet 20, the exhaust gas is guided to the secondary combustion unit 10 at the upper part of the exhaust gas treatment device, and flows downward toward the temperature reducing unit 11 below the secondary combustion unit. An outlet outlet burner 4 is installed in the first duct 23 and in the vicinity of the outlet, and a secondary combustion burner 5 is installed in the vicinity of the inlet of the secondary combustion section so that the temperature of the exhaust gas does not fall below a certain temperature (800 ° C.). It is ignited as necessary.

  From the tap outlet burner 4 and the secondary combustion burner 5, a mixed gas of fuel (oil, city gas, LPG gas, etc.) and air is ejected. By maintaining the secondary combustion unit 10 at a certain temperature or higher, dioxins and precursors thereof can be suppressed, and adhesion of fly ash can be prevented. Therefore, the secondary combustion burner 5 is not necessarily an essential component as long as the exhaust gas temperature is maintained at a temperature necessary for suppressing dioxins.

  In order to suppress dioxins and their precursors in the secondary combustion section 10, it is necessary to maintain (i) combustion at 800 ° C. or higher, (ii) residence time of 2 seconds or more, and (iii) mixing with combustion gas. Is done. On the other hand, the melting point of fly ash is 300 ° C to 800 ° C. In order to prevent adhesion of fly ash, it is required to avoid this melting point temperature.

  A cooling water nozzle 12 and a cooling air nozzle 13 are installed in the temperature reducing unit 11 and blow water and air in order to lower the temperature of the exhaust gas. The exhaust gas can be cooled to about 200 ° C. in a short time, and the temperature at which dioxins are easily re-synthesized can be avoided. The exhaust gas sent from the secondary combustion unit 10 to the temperature reducing unit 11 at 800 ° C. or higher is first cooled to about 500 ° C. by water ejected from the cooling water nozzle 12 and then ejected from the cooling air nozzle 13. Cooled to about 200 ° C. by air.

  Since dioxins decomposed in the secondary combustion section 10 are re-synthesized in a temperature environment of about 300 ° C. to 400 ° C., it is necessary to cool the exhaust gas in a short time. That is, the temperature distribution in the exhaust gas treatment apparatus is clearly divided into a high temperature part of 800 ° C. or higher in the secondary combustion part 10 and a low temperature part of approximately 200 ° C. or less in the temperature reducing part 11, and a temperature space in the middle is widened. Desirably not. When the exhaust gas can be cooled only with cooling air, the cooling water may not be sprayed.

  In the exhaust gas treatment apparatus in which the secondary combustion unit 10 and the temperature reduction unit 11 are integrated, the external material is a cylindrical shape made of a heat-resistant metal material. A fireproof castable is installed in the internal secondary combustion section 10, and a heat-resistant coating is applied to the temperature reducing section 11 having a lower temperature than the secondary combustion section 10 to protect the structure of the exhaust gas treatment apparatus from heat.

  The exhaust gas is then sent to the dust removing device 15. At this time, the exhaust gas temperature is cooled to 150 ° C. in the vicinity of the entrance of the dust removing device. Examples of the dust removing device 15 include an electric dust collector, a bag filter, and a multi-cyclone. In this embodiment, dust is collected by a bug filter. As the filter cloth used in the bag filter, a fine cloth such as polyester, polyamide, or polypropylene, or felt, heat-resistant nylon, glass fiber, or Teflon (trademark) is used. Therefore, the exhaust gas needs to be cooled to a temperature at which these filter cloths can be passed. The collected dust is discharged out of the dust removing device by the ash discharging device 16 provided at the lower part of the dust removing device. An exhaust gas fan 17 is disposed behind the dust removal device, and the exhaust gas fan 17 draws the exhaust gas so that the exhaust gas sequentially flows from the ash melting furnace 3 to the secondary combustion unit 10, the temperature reduction unit 11, and the dust removal device 15. Exhaust gas excluding dust is rendered harmless through a denitration device, a desulfurization device, or the like.

  In order to monitor the temperature of the exhaust gas, temperature measuring devices 24, 25, 26, and 27 are installed at the secondary combustion unit inlet, the temperature reducing unit inlet, the temperature reducing unit outlet, the dust removing device inlet, and the dust removing device outlet. Depending on the measurement result of the exhaust gas temperature of the temperature measuring device, the combustion gas spray from the secondary combustion section burner 5 and the water spray from the cooling water nozzle 12 of the temperature reducing section are performed as necessary.

  On the other hand, metal and slag are generated from the ash melted in the ash melting furnace 3. The slag discharged from the tap outlet 20 flows through the tap 21 and is discharged through the granulated nozzle cover 35 branched below the first duct. The slag is crushed and cooled by the cooling water discharged from the granulated water nozzle 6 in the branched duct. Thereafter, the slag accumulates in the cooling water tank 7 and is transported to the slag pit / metal pit 9 by the slag discharge conveyor 8. The slag may be cooled by air, or may be rapidly cooled or gradually cooled. The metal is also tilted out from the spout, cooled in the same way as the slag, and transported to the slag pit / metal pit 9.

  Since the secondary combustion unit 10 and the temperature reducing unit 11 are integrated and exist in the same cylinder, it is only necessary to install one deposit carry-out device 14 in the exhaust gas treatment device. Deposits and fly ash falling from the secondary combustion unit 10 and the temperature reducing unit 11 gather in the hopper 28 below the temperature reducing unit. The hopper 28 is narrowed down toward the deposit carry-out device in order to connect the tower of the secondary combustion section / temperature reduction section and the deposit discharge device 14. The deposits collected in the hopper 28 are removed by the deposit carry-out device 14. It is no longer necessary to separately place the deposit carry-out device 14 at the lower part of the secondary combustion chamber and the lower part of the temperature reduction tower as in the prior art. The deposit carry-out device 14 includes a crushing unit and a conveying unit. The crushing part plays a role of crushing the sediment accumulated in the hopper 28. The crushed deposit is placed on a transport unit and collected in a molten fly ash storage tank. The sediment is then hardened with chelate and concrete and disposed of. A rotary valve or the like can be used for the crushing unit, and a conveyor (a belt conveyor, an apron conveyor, a bread conveyor, a screw conveyor, or the like) can be used for the transfer unit.

  Since the second duct 31 that has been necessary in the past is no longer necessary, the fly ash accumulation at this portion is eliminated. That is, it is no longer necessary to install a cleaning device.

  In the second mode for carrying out the present invention shown in FIG. 3, when the secondary combustion unit 10 cannot be installed below the tap outlet 20, the first duct 23 does not rise greatly upward. It connects to the next combustion part 10. The spout opening portion duct 22 is connected to the water granulation nozzle cover 35, and the upper portion of the water granulation nozzle cover 35 is connected to the first duct 23. The first duct 23 does not have a horizontal surface and prevents fly ash from accumulating and blocking. Others are the same as the first embodiment.

The figure of the ash treatment equipment which has the exhaust gas treatment equipment of the 1st form for carrying out the present invention. The figure which showed the relationship between the shape and tilting of the tap outlet duct in the ash processing equipment which has the waste gas processing apparatus of the 1st form for implementing this invention. The figure of the ash treatment equipment which has an exhaust gas treatment device of the 2nd form for carrying out the present invention. The figure of the ash processing equipment which has an exhaust gas processing apparatus of a prior art. The figure of the ash processing equipment which has an exhaust gas processing apparatus of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Input ash storage tank 2 ... Ash fixed quantity supply apparatus 3 ... Ash melting furnace 4 ... Outlet burner 5 ... Secondary combustion burner 6 ... Granulated water nozzle 7 ... Cooling water tank 8 ... Slag discharge conveyor 9 ... Slag pit / metal pit DESCRIPTION OF SYMBOLS 10 ... Secondary combustion part 11 ... Temperature reduction part 12 ... Cooling water nozzle 13 ... Cooling air nozzle 14 ... Sediment discharge device 15 ... Dust removal device 16 ... Ash discharge device 17 ... Exhaust gas fan 18 ... Tilt device 19 ... Tilt shaft 20 ... Outlet port 21 ... Outlet port 22 ... Outlet port duct 23 ... First duct 24 ... Secondary combustion section inlet temperature measuring device 25 ... Temperature reducing section inlet temperature measuring device 26 ... Temperature reducing section outlet temperature measuring device 27 ... Dust removal device inlet temperature measuring device 28 ... Hopper 29 ... Secondary combustion chamber 30 ... Temperature reducing tower 31 ... Second duct 32 ... Air blaster 33 ... Third duct 34 ... Fourth duct 35 ... Granulated nozzle cover

Claims (6)

In an ash treatment facility comprising an ash melting furnace, and an exhaust gas treatment device comprising a secondary combustion section for treating the exhaust gas from the ash fusion furnace and a temperature reduction section,
The reduced temperature portion Rutotomoni disposed below the secondary combustion unit,
A granulation nozzle cover provided with a granulated water nozzle that is connected to the tap port provided in the ash melting furnace via a tap port duct and crushes and cools the slag with cooling water is provided,
Ash treatment equipment, wherein Rukoto such communicates the upper portion of the upper and the secondary combustion unit of Domizu砕nozzle cover by the duct having no horizontal plane.   The ash treatment facility according to claim 1, wherein the secondary combustion section is provided below the outlet of the ash melting furnace.   The ash treatment facility according to claim 1 or 2, wherein the secondary combustion unit and the temperature reducing unit are integrally provided.   3. The ash treatment facility according to claim 1, wherein a deposit discharge device is disposed only below the temperature reducing unit in the exhaust gas treatment device. 4.   4. The ash treatment facility according to claim 3, wherein the secondary combustion section and the temperature reducing section are formed of a cylinder built substantially vertically. 5. The ash treatment facility according to claim 4, wherein the deposit discharge device includes a crushing unit and a transfer unit .

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