JP4377292B2 - Waste treatment apparatus and exhaust gas treatment method - Google Patents

Description

The present invention recovers heat from combustion gas, gasification gas, or pyrolysis gas that is exhaust gas discharged from an incinerator, gasification furnace, or pyrolysis furnace, and collects dust from the exhaust gas to remove harmful gas components. The present invention relates to a waste treatment apparatus and an exhaust gas treatment method.

  Plants that perform combustion treatment, gasification treatment, and pyrolysis treatment of waste such as municipal waste and industrial waste include incinerators, gasification furnaces, pyrolysis furnaces, exhaust heat recovery equipment such as boilers, and exhaust gas treatment equipment It consists of Normally, exhaust gas discharged from an incinerator is recovered by heat in a heat exhaust boiler, cooled, then dust removed and detoxified through a dust collector, exhaust gas cleaning device, etc., and discharged into the atmosphere by a chimney. Conventionally, in such an incineration processing plant, an incinerator and a boiler have an integral structure, but an exhaust gas processing device such as a dust collector is configured as an independent device. Further, the fly ash removed by the dust collector is carried out of the system as special waste through processing steps such as melting, dechlorination and solidification alone.

FIG. 1 is a diagram showing a flow of this type of conventional incineration processing plant. As shown in the figure, the exhaust gas discharged from the incinerator 101 is heat recovered and cooled through a boiler 102 and a superheater 103. Thereafter, a desalting agent 104 is added, dust in the exhaust gas is collected and removed through the bag filter 105, further harmful gas is removed through the catalytic reaction tower (SCR) 106, and discharged from the chimney 107 to the atmosphere. .
JP 2001-116233 A

(1) In a treatment plant that burns, gasifies, and thermally decomposes waste, the exhaust gas generated and discharged in the furnace contains acid gases such as dioxins, hydrogen chloride, and sulfur oxides. . Normally, dioxins generated in a combustion furnace due to high-temperature combustion are oxidatively decomposed and discharged in as little as possible conditions, but the recombination temperature range of dioxins in the exhaust heat recovery device such as a boiler installed in the subsequent stage When exhaust gas passes through the vicinity of 300 ° C. to 600 ° C., a phenomenon that increases due to resynthesis of dioxins is observed. Factors for resynthesis include the temperature range, heavy metals in dust, the presence of hydrogen chloride, and the like. The present invention, 600 ° C. to 1200 to remove the dust in the range of ° C., re-synthesis temperature region to eliminate dust in the dioxins waste processing apparatus that can be suppressed recombining, and exhaust gas treatment method The purpose is to provide.

(2) In normal processing steps, a large amount of dioxins is contained in the fly ash. Fly ash is treated as a special management waste such as melting, dechlorination, solidification, and the concentration regulation is set to 3 ng / g-TEQ or less. Another object of the present invention is to reduce the amount of fly ash that requires special treatment by removing dust in a high-temperature region inside a heat recovery device such as a boiler, thereby reducing the total amount of dioxins and reducing the amount of fly ash treatment equipment. waste processing apparatus that can be made compact device, and to provide an exhaust gas treatment method.

(3) Another object of the present invention can be performed to reduce the removal and fly ash generation of dioxins in fly ash, reduction can Ru waste processing apparatus occurrence of dioxins from property, And providing an exhaust gas treatment method.

(4) Exhaust heat recovery devices such as boilers are being increased in temperature and pressure from the viewpoint of higher efficiency. However, there are problems such as corrosion of the material due to the exhaust gas temperature, the properties of the exhaust gas, and the state of dust in the exhaust gas. Another object of the present invention is to reduce the thickness of the pipe by eliminating the soot blower in the subsequent heat recovery section (superheater, etc.) by removing the dust on the high temperature side, reducing the dust in the exhaust gas, etc. Corrosion suppression. With the advantage in selecting the material of the superheater unit by thinning inhibition and corrosion inhibition, waste that can be effectively used further heat for may heat recovery apparatus such as a boiler is high temperature and high pressure of wastes processing apparatus and exhaust gas treatment It is to provide a method.

(5) Another object of the present invention, imparted dust collector ability to heat recovery apparatus such as a boiler, a conventional dust-catcher of the body heat radiation amount of reduction and waste processing apparatus that can be space saving And providing an exhaust gas treatment method.

In order to solve the above problems, the present invention provides an incinerator, a gasification furnace, or a pyrolysis furnace for treating waste, and an exhaust gas treatment apparatus for treating exhaust gas discharged from the incinerator, the gasification furnace, or the pyrolysis furnace, The waste gas treatment device comprises a waste heat recovery device in which a casing is formed with a radiant heat transfer surface, and a dust collecting part disposed inside the waste heat recovery device, The exhaust gas discharged from the incinerator, gasification furnace, or pyrolysis furnace is guided to the waste heat recovery device, and dust in the exhaust gas is collected and removed at the dust collector, and the heat of the exhaust gas is recovered from the radiation heat transfer surface of the casing. characterized in that it.

Further, the present invention provides the above waste treatment apparatus, wherein a reaction product is produced by reacting with hydrogen chloride or sulfur oxide in the exhaust gas between the incinerator, the gasification furnace or the thermal decomposition furnace and the waste heat recovery apparatus. And a desalting agent injection device for injecting a desalting agent to be injected .

Further, in the above waste treatment apparatus, dust collection section, and characterized in that it is constituted by a ceramic filter having arranged heat resistance high temperature region of 600 ° C. to 1200 ° C. in the waste heat recovery device To do.

Further, in the above waste treatment apparatus, the Se la Mick filter, characterized in that by supporting a catalyst component having the oxidative decomposition function of dioxins.

Further, in the above waste treatment apparatus, characterized in that the dust obtained by dust in the dust collecting portion of the exhaust gas treatment apparatus, comprising a supply means for supplying to the incinerator or gasifier or thermal decomposition furnace And

The present invention also relates to an exhaust gas treatment method for treating exhaust gas discharged from an incinerator, gasification furnace or pyrolysis furnace for treating waste, and exhaust gas discharged from the incinerator, gasification furnace or pyrolysis furnace. casing is formed by radiation heat transfer surface and guided to the waste heat recovery device provided with a dust collection unit therein, while the dust collecting removed dust contained in the exhaust gas in the dust collecting unit, the casing of the radiation heat transfer The heat of the exhaust gas is recovered from the surface .

Further, the present invention is the above exhaust gas treatment method, wherein the dust collecting part is a ceramic filter having heat resistance disposed in a high temperature region of 600 to 1200 ° C. of the waste heat recovery device , and dust is collected by the ceramic filter. It is characterized by removing dust.

Further, in the above exhaust gas treatment method, the catalyst component is supported on cell La Mick filter, and performs oxidative decomposition of dioxins.

Further, in the above exhaust gas processing method, in the exhaust gas discharged from the incinerator or gasifier or thermal decomposition furnace is mixed desalting agent hydrogen chloride in the exhaust gas is reacted with sulfur oxides to obtain a reaction product Te, and removing with dust in the dust collecting unit in the waste heat winding device the reaction product.

According to the present invention , the dust collection unit for collecting and removing dust in the exhaust gas is provided in the waste heat recovery device, and the casing of the dust collection unit is the waste heat recovery unit. without providing the dust collector was required separately, it is possible to compact of the apparatus. In addition, a dust collection part is provided in a region higher than the resynthesis temperature of dioxins in the waste heat recovery system, and by removing fly ash in the gas, dioxins are reduced in the gas cooling process after that. Resynthesizing can be suppressed.

Further, according to the present invention, provided the harmful gas removal unit in the waste heat recovery apparatus, since the integrated harmful gas removing unit and the dust collecting section, it is possible to further compact of the apparatus. Also, dust and products can be easily processed. In addition, the dust and products removed in the dust collection unit are returned to the combustion furnace, gasification furnace, or pyrolysis furnace, so the unburned fly ash and dioxins in the dust are completely burned and discharged as combustion ash. Therefore, the generation of fly ash in the device is eliminated, and a single fly ash treatment device is not required.

Further , according to the present invention , the dust collecting part is composed of a heat-resistant ceramic filter disposed in a high temperature region of 600 ° C. to 1200 ° C. in the waste heat recovery device, so that the recombination temperature region of dioxins Dioxins are reduced and the subsequent gas cooling process is performed by disposing a ceramic filter in a temperature range of 600 ° C. to 1200 ° C., which is higher than 300 ° C. to 600 ° C., and collecting dust such as fly ash. Recombination of dioxins at the plant can be suppressed.

Further , according to the present invention , since the ceramic filter carries the catalyst component having the function of oxidative decomposition of dioxins, the harmful components of the dioxins can be oxidatively decomposed and rendered harmless by the ceramic filter. Further, by desalting with a ceramic filter, hydrogen chloride (HCl) and sulfur oxide (SOx) are reduced, so that the problem of poisoning and clogging when a catalytic reaction tower is installed in the subsequent stage can be solved.

In addition, according to the present invention , the dust collection unit of the waste heat recovery device has a function of collecting heat after collecting and removing dust in the exhaust gas, and thus further reducing the resynthesis of dioxins. Since it is possible to suppress pipe thinning and corrosion by eliminating the stop heater in the heat recovery section (superheater), it is not necessary to select a material with excellent wear resistance and corrosion resistance, and it is easy to select the superheater material. It becomes.

Moreover, according to the present invention , the exhaust gas treatment device includes a waste heat recovery device having a dust collection unit that collects and removes dust in the exhaust gas and a casing of the dust collection unit that recovers heat from the exhaust gas. Therefore, it is possible to provide a waste treatment apparatus having the above effects.

In addition, according to the present invention , since the desalting agent injection device for mixing the desalting agent into the exhaust gas discharged from the incinerator, gasification furnace or pyrolysis furnace is provided, the exhaust gas discharged from the furnace It is possible to provide a waste treatment apparatus in which a desalting agent is mixed, reacted with hydrogen chloride and sulfur oxide, and the reaction product is collected and removed by the dust collection unit.

In addition, according to the present invention , since the dust obtained by the dust removal in the dust collecting unit of the exhaust gas treatment apparatus is provided with the supply means for supplying the dust to the incinerator, the gasification furnace, or the pyrolysis furnace, Ashes and dioxins are combusted and pyrolyzed, and can be carried out of the system as incinerated ash.

In addition, according to the present invention , heat is recovered from the exhaust gas in the waste heat recovery device, dust contained in the exhaust gas is collected and harmful gas components in the exhaust gas are further removed, so that the exhaust heat recovery device By removing fly ash in the exhaust gas in the region higher than the re-synthesis temperature of dioxins, the fly ash can be removed without dioxins being re-synthesized. The resynthesis of dioxins in the gas cooling process can be suppressed.

In addition, according to the present invention , dust is collected and removed by the heat-resistant ceramic filter provided in the waste heat recovery apparatus and disposed in a high temperature region of 600 ° C. to 1200 ° C., so that dioxins are re-synthesized. By removing the dust under the conditions that do not, the reduction in the amount of dioxins derived from dust and the resynthesis of dioxins in the subsequent gas cooling process can be suppressed.

Further , according to the present invention , since the dioxins are oxidatively decomposed by the catalyst component carried on the ceramic filter, the harmful components of the dioxins can be oxidatively decomposed and rendered harmless by the ceramic filter. Further, by desalting with a ceramic filter, hydrogen chloride (HCl) and sulfur oxide (SOx) are reduced, so that the problem of poisoning and clogging when a catalytic reaction tower is installed in the subsequent stage can be solved.

In addition, according to the present invention , a desalting agent is mixed in exhaust gas discharged from an incinerator, a gasification furnace, or a pyrolysis furnace to obtain a reaction product of an acidic component in the gas and the desalting agent. since the reaction product is removed together with the waste heat recovery device Deda strike relatively easily hydrogen chloride, it is possible to remove sulfur oxides.

  FIG. 2 is a diagram showing a schematic configuration example of a stoker-type waste incinerator to which the gas treatment apparatus and the exhaust gas treatment method according to the present invention are applied. In FIG. 2, 1 is a stoker-type incinerator, 2 is a waste heat boiler, 3 is a waste pit, 4 is a hopper, 5 is a waste crane, and 6 is a dust supply device that supplies waste from the lower part of the hopper 4 to the incinerator 1. It is. Here, the garbage collected in the garbage pit 3 is transferred from the garbage pit 3 to the hopper 4 by the garbage crane 5. The combustion furnace 1 has a divided structure of a drying zone 1a for drying waste, a combustion zone 1b for burning waste, a combustion zone 1c, and a post-combustion zone 1d from the left side of FIG. 2, and stokers 7a and 7b provided respectively. , 7c, 7d to transfer waste in the incinerator 1, and through air adjustment dampers 8a, 8b, 8c, 8d provided in the air introduction passages 9a, 9b, 9c, 9d connected to the respective lower portions Air is supplied.

  In addition, secondary air is supplied from the secondary air blower 20 through the air introduction path 19 to the outlet 1e of the incinerator 1 to completely burn combustible components in the exhaust gas. Ashes 10a to 10f remaining after incineration of garbage are collected in an ash extrusion device (not shown), discharged outside the system, and supplied to the next processing step. Although not shown, the waste incineration plant equipment also includes a dust collector that removes soot in the exhaust gas generated by incineration, a catalytic reaction tower that decomposes harmful gases, and the like. (Not shown) Moreover, the waste heat boiler 2 is installed in the upper part of the incinerator 1, and the vapor | steam 100 is generated using the heat | fever which carried out the waste incineration process. Although not shown, this steam 100 is used for power generation use in the steam turbine and in-site heat use.

  The waste incineration plant equipment further includes a temperature sensor 11 for measuring the exhaust gas temperature at the outlet 1e of the incinerator 1, a steam amount sensor 12 for measuring the steam amount at the boiler outlet, and an oxygen for measuring the oxygen concentration in the exhaust gas at the furnace outlet 1e. A concentration sensor 13, an industrial television camera 14 that monitors the combustion state of the dust in the incinerator 1 and monitors a combustion completion point, and an image processing device are provided. Although not shown, a temperature sensor, a pressure sensor, a flow sensor, and the like are provided at necessary positions.

  Based on the signals from these sensors, the amount of dust supplied from the dust supply device 6 into the incinerator 1, the air to the drying zone 1 a, the combustion zone 1 b, the combustion zone 1 c, and the post-combustion zone 1 d in the incinerator 1. The supply amount, the movement speed of the garbage by the stokers 7a, 7b, 7c, 7d, etc. are PID or arithmetically controlled. Further, the crane 5 is provided with a weight sensor 15 for measuring the weight of a handful of garbage. The weight of the handful of garbage and a level change when it is put into the hopper 4 are measured by a sensor (not shown), The input dust density ρ is calculated from the volume increase amount, and the dust supply amount is adjusted by the dust supply device 6 according to the density. In FIG. 1, 16 is a burner, and 17 is a forced air blower that pushes air through the air introduction path 9. Further, reference numeral 21 denotes a platform, and the garbage collected from the platform 21 by the garbage truck 22 is put into the garbage pit 3.

  FIG. 3 is a view showing a configuration of a waste incineration processing apparatus in which the gas processing apparatus according to the present invention is used in the above stoker type incinerator. As shown in the figure, the waste incineration processing apparatus has a gas processing apparatus 30 according to the present invention connected to an outlet 1e of a stoker type incinerator 1. The gas treatment device 30 includes a first boiler 31, a second boiler 32, and a superheater (convection heat transfer unit) 33, and the exhaust gas G discharged from the outlet 1 e of the incinerator 1 is the first boiler 31, the second boiler 32, and the like. It passes through the boiler 32 and the superheater and is discharged from the boiler outlet 34, and the catalytic reaction tower (SCR) 40, the economizer 41, and the induction blower 42 are discharged from the chimney 43 to the atmosphere. The water supply 105 is heated by the economizer 41 (heat recovered) and supplied to the boiler.

  Complete combustion is performed on the stokers 7a, 7b, 7c, and 7d of the stoker-type incinerator 1, and the incinerated ash 10f after combustion is discharged to the bottom of the furnace. In the gas processing apparatus 30, a ceramic filter 35 is incorporated in the second boiler 32. The first boiler 31 and the second boiler 32 are formed by radiation heat transfer surfaces, and the exhaust gas G is absorbed by passing through it. The ceramic filter 35 is incorporated in the second boiler 32, but depending on the scale of the boiler structure, the ceramic filter 35 is installed in a state of being suspended from a frame outside the boiler. The temperature range is designed to drop to about 1200 ° C. to 750 ° C. at the first boiler 31 and to about 750 ° C. to 600 ° C. for the second boiler 32. Moreover, the casing of the dust collection part by the ceramic filter 35 is comprised with a boiler heat exchanger tube, and waste heat is absorbed also here.

  The exhaust gas that has passed through the ceramic filter 35 is recovered by a superheater (convection heat transfer unit) 33 in the same boiler and sent to a heat utilization device such as a steam turbine as the amount of steam generated in the boiler. Here, since the fly ash in the exhaust gas is removed, the soot blow that has been indispensable in the past is not installed. Further, it is possible to omit a thickness reduction prevention device such as a protector installed in the heat transfer tube of the superheater 33. Fly ash adhering to the surface of the ceramic filter 35 incorporated in the second boiler 32 is detected by the differential pressure between the inlet and outlet of the second boiler 32, and when the differential pressure rises above a predetermined level, The high-temperature air 101 is pulse-injected into the interior through the air injection nozzle 36, so that the adhering fly ash 102 is removed and returned to the incinerator 1 from the lower chute 37 of the second boiler 32.

  The temperature of the high temperature air 101 for pulses is set so that the surface temperature of the ceramic filter 35 can always be maintained at 550 ° C. or higher. The fly ash 102 returned to the incinerator 1 is retained in the post-combustion zone 1d of the incinerator 1 so that the unburned portion is completely burned and the dioxins are decomposed and discharged together with the combustion ash 10f. The Depending on the dust component and dust particle size, in-furnace spraying is also possible in consideration of the use of diatomaceous earth as a dusting aid.

  Further, the ceramic filter 35 may be loaded with a component having a catalytic function to have a function of oxidizing and decomposing dioxins to serve as a harmful gas removing unit. Further, a desalting agent may be mixed in the exhaust gas G from the incinerator 1 and reacted with hydrogen chloride and sulfur oxide, and the reaction product may be collected and removed with a ceramic filter. Since the removed dust is returned to the incinerator 1 from the lower chute 37 of the second boiler 32, the fly ash, dioxins, and reaction products contained in the dust are combusted, pyrolyzed, and incinerated ash. To be taken out of the system.

  FIG. 4 is a diagram showing a flow example of a waste treatment apparatus using the gas treatment apparatus according to the present invention. As shown in the figure, the exhaust gas G discharged from the incinerator 1 is heat-recovered by the first boiler 31, dust is removed by the ceramic filter (CF) 35 by the second boiler 32, and heat is recovered by the superheater 33. The NOx and the like are removed by the catalytic reaction tower (SCR) 38, detoxified, and discharged from the chimney 39 to the atmosphere. The desalting agent 104 is mixed in the exhaust gas of the first boiler 31 and reacted with hydrogen chloride and sulfur oxide, and the reaction product is collected and removed together with dust such as fly ash by a ceramic filter.

  In addition, although the example which uses the gas processing apparatus which concerns on this invention for the stoker type incinerator 1 was shown in the said example, an incinerator is not limited to a stoker type, For example, a fluid bed incinerator may be sufficient. In the case of a fluidized bed incinerator, since the amount of dust in the exhaust gas is increased as compared with a stoker type furnace, the gas treatment apparatus of the present invention can be suitably used. Moreover, it is not limited to an incinerator and may be a gasification furnace or a pyrolysis furnace. The present invention is effective for treating dust contained in exhaust gas (combustible gas) discharged from a gasification furnace or a pyrolysis furnace. Further, the exhaust gas treatment flow at the latter stage is not limited to that shown in the embodiments, and the exhaust gas treatment method can be changed depending on the requirements.

  In addition, the waste heat recovery device with a high-temperature dust collecting function according to the present invention can be an independent device separate from the incinerator, gasification furnace, etc., and the exhaust gas at that time is transferred in a duct connecting both devices. The In this way, when a separate stand-alone device is used, repair or the like becomes easier when trouble occurs.

It is a figure which shows the flow of the conventional incineration processing plant. 1 is a schematic configuration example of a stoker-type incineration blunt according to the present invention. It is a figure which shows the structural example of the waste incineration processing apparatus which concerns on this invention. It is a figure which shows the flow of the waste disposal apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incinerator 2 Waste heat boiler 3 Garbage pit 4 Hopper 5 Garbage crane 6 Dust feeder 7a-d Stoker 8a-d Air adjustment damper 9a-d Air introduction path 10a-f Ash 11 Temperature sensor 12 Steam quantity sensor 13 Oxygen concentration sensor DESCRIPTION OF SYMBOLS 14 Industrial television camera 15 Weight sensor 16 Burner 17 Pushing fan 20 Secondary air pushing fan 21 Platform 22 Garbage truck 30 Gas treatment device 31 1st boiler 32 2nd boiler 33 Superheater 34 Boiler outlet 35 Ceramic filter 36 Air injection nozzle 37 Bottom Shoot

Claims (9)

In a waste treatment apparatus comprising an incinerator, a gasification furnace, or a pyrolysis furnace for treating waste , and an exhaust gas treatment apparatus for treating exhaust gas discharged from the incinerator, gasification furnace, or pyrolysis furnace,
The exhaust gas treatment apparatus includes a waste heat recovery device in which a casing is formed with a radiant heat transfer surface, and a dust collection unit disposed inside the waste heat recovery device,
The exhaust gas discharged from the incinerator, gasification furnace, or pyrolysis furnace is led to the waste heat recovery device, dust in the exhaust gas is collected and removed by the dust collection unit, and the radiant heat transfer surface of the casing A waste treatment apparatus for recovering heat of exhaust gas . The waste treatment apparatus according to claim 1 ,
Between the front Symbol incinerators or gasification furnace or thermal decomposition furnace the waste heat recovery apparatus, the hydrogen chloride in the exhaust gas, desalination of injecting desalting agent to produce a reaction product is reacted with sulfur oxides A waste treatment apparatus, further comprising an agent injection device. The waste disposal apparatus according to claim 1 or 2 ,
2. The waste treatment apparatus according to claim 1, wherein the dust collection unit is composed of a heat-resistant ceramic filter disposed in a high temperature region of 600 ° C. to 1200 ° C. in the waste heat recovery apparatus. The waste treatment apparatus according to claim 3, wherein
A waste treatment apparatus , wherein the ceramic filter carries a catalyst component having a function of oxidative decomposition of dioxins . The waste disposal apparatus according to any one of claims 1 to 4 ,
A waste treatment apparatus comprising supply means for supplying dust obtained by dust removal in a dust collection unit of the exhaust gas treatment apparatus to the incinerator, gasification furnace, or pyrolysis furnace. In the exhaust gas processing method for processing an exhaust gas discharged from an incinerator or gasifier or thermal decomposition furnace for processing waste,
The exhaust gas discharged from the incinerator, gasification furnace, or pyrolysis furnace is led to a waste heat recovery device in which a casing is formed with a radiant heat transfer surface and a dust collection part is provided inside, and the exhaust gas is emitted from the dust collection part. An exhaust gas treatment method characterized by collecting and removing dust contained therein and recovering heat of the exhaust gas from a radiant heat transfer surface of the casing . In the exhaust gas treatment method according to claim 6 ,
The dust collection unit is a heat-resistant ceramic filter disposed in a high temperature region of 600 ° C. to 1200 ° C. of the waste heat recovery apparatus, and the dust is collected and removed by the ceramic filter. Processing method. The exhaust gas treatment method according to claim 7 ,
An exhaust gas treatment method, wherein dioxins are oxidatively decomposed with a catalyst component supported on the ceramic filter. In the exhaust gas treatment method according to any one of claims 6 to 8 ,
A reaction product is obtained by mixing a desalting agent in the exhaust gas discharged from the incinerator, gasification furnace or pyrolysis furnace and reacting with hydrogen chloride and sulfur oxide in the exhaust gas, and the reaction product Is removed together with the dust by a dust collecting section in the waste heat recovery device.

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