JP5189021B2 - Operation method of gasification melting furnace - Google Patents

Description

  The present invention relates to a method for operating a gasification melting furnace, and more particularly, to a method for operating a gasification melting furnace when gasifying a shredder dust of industrial waste such as a scrap car and an electric appliance.

  As equipment for melting industrial waste mixed with metals such as lead, zinc, copper, and vinyl chloride as a chlorine source, such as automobile shredder dust (Automobile Shredder Residue = ASR) An industrial waste melting treatment facility equipped with a stratified gasification furnace is known. For example, there is a melting treatment facility as disclosed in Patent Document 1.

  The fluidized bed type gasification furnace disclosed in Patent Document 1 is for the purpose of recovering valuable metals contained in the above-mentioned industrial waste, and is industrially discarded in a melting treatment facility as shown in FIG. Processing of things. The main equipment of this melting processing facility will be described together with the outline processing steps.

First, as shown in the schematic configuration diagram of the melting treatment facility in FIG. 1, sludge A1 is stored in the first storage 1, and industrial waste A2 containing valuable metals is stored in another second storage. Store in 2.
Sludge A1 and the like from the first storage 1 are put into a supply feeder 4 by a supply conveyor 3 together with industrial waste A2 and the like finely crushed by a crusher (not shown), and a certain amount flows from the supply feeder 4 The stratified gasifier 11 is charged.
Here, the industrial waste A2 includes shredder dust containing valuable metals and plastics obtained by treating automobiles, home appliances, and the like with a shredder, industrial waste plastics, and the like.

  In the fluidized bed gasification furnace 11, as shown in FIG. 1, the industrial waste A 2 and the sludge etc. A 1 that have been input are converted into a fluidized bed in the fluidized bed gasification furnace 11 by the air C blown from the fluidized bed 12. Form and circulate. In the fluidized bed gasification furnace 11, the waste plastic is pyrolyzed and gasified while suppressing the combustion of the waste plastic in the industrial waste A2. Thereafter, the pyrolysis gas E and the like generated in the gasification furnace 11 are transferred to the melting furnace 21.

  In the melting furnace 21, the pyrolysis gas E and the like are transferred and simultaneously burned while supplying air. As a result, the pyrolysis gas E burns and becomes exhaust gas F and is discharged. Here, considering that the temperature of the exhaust gas F is in the range of 200 to 600 ° C., harmful substances such as dioxin are re-synthesized, and the time in this temperature range is reduced to prevent the generation of harmful substances again. Therefore, the exhaust gas F from the melting furnace 21 is indirectly cooled by the heat exchanger 26, the waste liquid L1 is sprayed on the waste liquid decomposition part 42 of the quenching tower 41, and industrial water (technical water as cooling water) is further cooled by the quenching part 43. ) L2 is sprayed to cool the exhaust gas F.

  Here, the waste liquid produced by smelting contains metal ions and acids, and the waste liquid produced at chemical factories, etc. contains inorganic substances, organic substances, etc., but these are preferably incinerated, so the waste liquid decomposition unit 42 includes a step of thermally decomposing the waste liquid L1. By exposing the waste liquid L1 to a high temperature, organic substances and acids contained in the waste liquid L1 are decomposed, and inorganic substances and metal ions are converted into oxides and collected by the bag filter 51 via the slaked lime blowing device 52. And the slag G collect | recovered from the melting furnace 21 is granulated. Further, the exhaust gas is discharged from the exhaust bump 81 to the atmosphere via the neutralization tower 61 and the mist cot rel 71.

  An outline of the structure of the fluidized bed gasification furnace 11 will be described. A granular material, for example, “sand” serving as a heat medium is introduced from a heat medium inlet located above the furnace bottom, and an air outlet hole provided in the furnace bottom is provided. A fluidized bed is formed in which convection is caused by blowing air upward. And the sand as a heat medium is discharged | emitted from the inside of the furnace through the discharge chute 15 extended below from a furnace bottom part with the incombustible material in the waste thrown in from the upper part of a furnace bottom part. The sand once discharged is put into the furnace again from above the bottom of the furnace through a circulation passage (not shown).

  However, although the fluidized bed gasification furnace 11 of Patent Document 1 discharges sand and non-combustible material as a heat medium through the discharge chute 15, there is a problem that clinker adheres to the discharge chute 15. If the clinker adheres in the discharge chute 15 and the discharge chute 15 is closed, sand and incombustibles cannot be discharged and circulated. When the sand introduced from the upper part of the bed is discharged from the discharge chute 15 located at the lower part of the fluidized bed, the discharge speed of the sand flowing through the discharge chute is set within a range that does not fall below the furnace combustion maintenance temperature. We have proposed a method for operating a fluidized bed gasifier that controls the discharge rate per unit area and, if necessary, injects steam into the discharge chute to prevent clinker formation.

  However, in the operation method of the fluidized bed type gasification furnace disclosed in Patent Document 2, sand and incombustibles are prevented from dropping due to a shelf hanging phenomenon in the discharge chute due to the shape of an inevitable path from the discharge chute to the discharge conveyor. There was a problem that. When the shelves occur, sand and incombustibles cannot be extracted, so the operation of the gasifier must be stopped and the countermeasures must be dealt with. Therefore, the applicant of the present application has proposed a fluidized bed type gasification furnace that prevents the occurrence of a shelf hanging phenomenon in the discharge chute and enables continuous extraction of sand and incombustibles (Patent Document 3). ).

JP-A-11-302748 JP 2005-282960 A JP 2008-232523 A

  In the melting treatment of industrial waste by the gasification melting furnace as described above, conventionally, the neutralization was performed by draining the dust collected from the quenching tower, the dust collected by the bag filter, or the washing liquid in the neutralization tower or mist cotrel. Dust collected from the dredger was processed by a melting furnace in another facility. However, processing at another facility incurs a transportation cost of the dusts, and further entrusts a processing cost when processing the waste as waste. For this reason, it was considered that the collected and collected dusts were again put into a fluidized bed gasification furnace to be treated in the gasification melting furnace. % Of calcium is contained, when the collected dust is repeatedly processed in a fluidized bed gasification furnace, the calcium content adheres to the diffuser nozzle of the moving bed of the furnace, and the diffuser nozzle closes. There has occurred.

  In recent years, the life cycle of automobiles and home appliances has been shortened, so that a large amount of industrial waste such as ASR and home appliance shredder dust is generated, and its treatment is increasing year by year. For this reason, increasing the throughput per hour in conventional gasification melting furnaces increases the temperature of the melting furnace to over 1,400 ° C., increasing the burden on the heat-resistant bricks on the inner wall of the furnace, There was a problem that the lifetime was shortened.

  Therefore, the present invention is an operation of a gasification melting furnace capable of suppressing the rise in the temperature of the melting furnace and maintaining the life of the melting furnace even when processing an increasing amount of industrial waste more than before. It aims to provide a method.

  In addition, the present invention provides a quenching tower, a bag filter, a neutralization tower, or a mist cot rel when industrial waste containing valuable metals or chlorine such as ASR and home appliance shredder dust is treated in a gasification melting furnace. Gasification melting furnace that does not cause clogging of the aeration nozzle of the fluidized bed gasification furnace moving bed when the dust recovered from the neutralized soot after draining the cleaning liquid is treated again in the gasification melting furnace The purpose is to provide a method of operation.

  In order to achieve the above object, according to the first aspect of the present invention, a part of the industrial waste is formed by forming a fluidized bed by air blown from the lower side of the industrial waste introduced into the fluidized bed type gasification furnace. Gasification by pyrolysis collects incombustibles containing valuable metals, and pyrolysis gas generated in the gasification furnace and part of the incombustibles transferred by the pyrolysis gas are processed in the melting furnace to produce slag. In the operation method of the gasification melting furnace, the dust containing calcium is slurried and blown into the melting furnace.

  In order to achieve the above object, the invention according to claim 2 is the operation method of the gasification melting furnace according to claim 1, wherein the slurry of dust is leached with water to remove chlorine, and after dechlorination After removing the supernatant by dehydration or decantation, water is further added to form a slurry liquid.

  In order to achieve the above object, the invention described in claim 3 is the operation method of the gasification melting furnace according to claim 1 or 2, wherein the dust is dust collected from a quenching tower, dust collected by a bag filter, Any one of the dust collect | recovered from the neutralization tank which drained the washing | cleaning liquid in a neutralization tower or a mist cot rel was included, It is characterized by the above-mentioned.

  In order to achieve the above object, the invention described in claim 4 is characterized in that, in the operation method of the gasification melting furnace according to claim 2 or 3, the slurry liquid is sprayed from the vicinity of the top of the melting furnace into the furnace. .

  According to the operation method of the gasification melting furnace according to the present invention, since the dust containing calcium is slurried and blown into the melting furnace, the melting point of the slag is lowered from about 1,350 ° C. to about 1,250 ° C. And the fluidity | liquidity of slag can be ensured at temperature lower than before. Therefore, there is an effect that slag can be easily collected.

  In addition, according to the operation method of the gasification and melting furnace, the dust collected from the quenching tower, the dust collected by the bag filter, the dust collected from the neutralization soot treated with the washing liquid in the neutralization tower or mist cotrel Since calcium was included, if it was re-introduced into the fluidized bed gasification furnace in order to treat these dusts, there was a problem that the calcium content would block the diffuser nozzle. Thus, the problem of the obstruction of the diffuser nozzle is solved, and the fluidity of the slag in the melting furnace can be ensured as described above, which has the effect of two birds with one stone.

  Furthermore, according to the operation method of the gasification melting furnace according to the present invention, the dust recovered from the quenching tower, the dust collected by the bag filter, the cleaning liquid in the neutralization tower or the mist cotrel is recovered from the neutralization basin subjected to the drainage treatment. Since the slurry liquid, which was slurried after dechlorination, was sprayed from the vicinity of the top of the melting furnace into the furnace, it became an alternative to cooling water, and the temperature rise in the melting furnace due to mass processing was suppressed, and the furnace wall There is an effect that the deterioration of is prevented. Thereby, there is an effect that the life of the melting furnace is not shortened.

It is a schematic block diagram of the melting processing facility containing a gasification melting furnace. It is a flowchart of the operating method of the gasification melting furnace which concerns on this invention. It is sectional drawing of the melting furnace for showing spraying of a slurry liquid.

  Hereinafter, the operation method of the gasification melting furnace which concerns on this invention is demonstrated based on preferable one Embodiment. FIG. 2 is a flowchart of the operation method of the gasification melting furnace according to the present invention.

  First, industrial waste such as ASR and home appliance shredder dust is sieved with a trommel, and the sieved material is sieved into an undersize and an oversize based on a predetermined size, for example, about 40 mm × 40 mm (step) S1). As will be described later, the undersize is put into the fluidized bed gasification furnace 11 as it is (see FIG. 1). The oversize is sorted by a magnetic separator and divided into iron scrap and other parts (step S2). Further, the aluminum waste is removed by manual sorting (step S3), and the remaining sieved material is further pulverized to a predetermined size, for example, about 40 mm × 40 mm or less by a pulverizer (step S4). Then, this pulverized product and an undersized sieve product screened by a trommel, and waste plastics, wood waste, urethane, and the like are charged into the fluidized bed gasification furnace 11.

  In the fluidized bed gasifier 11, a fluidized bed is formed and circulated by the air C blown from the fluidized bed 12 (see FIG. 1), and the waste plastic contained in the pulverized industrial waste is heated. Decompose and gasify (step S5). Thereafter, the pyrolysis gas E generated in the fluidized bed gasification furnace 11 is transferred to the melting furnace 21.

  In the fluidized bed type gasification furnace 11, “sand” which is a particulate material serving as a heat medium introduced from a heat medium inlet located above is blown upward from an air blowing hole provided in the bottom of the furnace. A fluidized bed is formed by the air C. And the sand as a heat medium is discharged | emitted from the inside of the furnace through the discharge chute 15 extended below from a furnace bottom part with the incombustible material in the waste thrown in from the upper part of a furnace bottom part. The discharged incombustible material and sand are sieved by a sieving machine, and the sand is again put into the furnace from above the furnace bottom through a circulation passage (not shown). On the other hand, non-combustible materials are separated into large iron scraps and other things by a magnetic separator, and further sorted into mixed ball size and mixed metal containing aluminum. Further, the sand is pulverized by a pulverizer, and fine iron is recovered as iron sand by a magnetic separator not shown.

  When the pyrolysis gas E or the like is transferred to the melting furnace 21, the pyrolysis gas E is burned while supplying air into the melting furnace 21 (step S6). As a result, the pyrolysis gas E burns to become exhaust gas F and is transferred to the exhaust gas treatment facility. Here, considering that the temperature of the exhaust gas F is in the range of 200 to 600 ° C., harmful substances such as dioxin are re-synthesized, and the time in this temperature range is reduced to prevent the generation of harmful substances again. Therefore, the exhaust gas F sent from the melting furnace 21 is indirectly cooled by the heat exchanger 26, the waste liquid L1 is sprayed on the waste liquid decomposition part 42 of the quenching tower 41, and further, industrial water as cooling water in the quenching part 43. (Engineering water) L2 is sprayed to cool the exhaust gas F. As described above, the waste liquid L1 is sprayed because the waste liquid L1 contains metal ions and acids, and the waste liquid L1 generated in a chemical factory or the like contains inorganic substances, organic substances, etc., which can be incinerated. This is desirable. And the slag G collect | recovered from the melting furnace 21 is grind | pulverized with a water granulator, and the granulated slag is utilized as raw materials, such as a ground improvement agent, cement, an interlocking block.

  In the operation method of the gasification melting furnace according to the present invention, as shown in FIG. 3, the dust recovered from the quenching tower 41 is water leached and dechlorinated, and then the supernatant is removed by dehydration or decantation ( Step S8), repulped with water to make a slurry liquid (Step S9), sprayed from the top of the melting furnace 21 and used for cooling the furnace temperature. The cooled exhaust gas F is sent to the catalytic decomposition tower (step S12) via the bag filter 51. The dust collected by the bag filter 51 (step S10) is added with water and dechlorinated. The leached soot dehydrated by the filter press is repulped with water to form a slurry liquid (step S9), sprayed from the top of the melting furnace 21 and used for cooling the furnace temperature. Further, the exhaust gas F is released to the atmosphere through the neutralization tower 61 (step S13) and the mist cot rel 71 (step S14) (step S15). After dechlorination is performed by the equipment, neutralization and recovery are performed (step S16), and the neutralized soot recovered by filter pressing is further repulped with water to form a slurry liquid (step S9), from the top of the melting furnace 21. Spray to cool the furnace temperature.

  In this way, any of the dust recovered from the quenching tower 41, the dust recovered from the bag filter 51, and the dust recovered from the neutralization tower 61 and the neutralization soot recovered from the mist cot rel 71 contain calcium. Therefore, calcium is transferred to the slag G by adding water to this and repulping and spraying it again as cooling water into the melting furnace 21 as a slurry liquid. Therefore, the melting point of the slag G, which was about 1,350 ° C. until now, is lowered to about 1,250 ° C., and the fluidity of the slag G is ensured even when the temperature in the melting furnace 21 is lower than the conventional one. The collection work can be made more efficient. In addition, since the temperature in the melting furnace 21 can be made lower than before, the influence of the temperature on the heat-resistant brick and the like is improved, leading to extending the life of the melting furnace 21. Furthermore, there is a problem that when the recovered dust is re-introduced into the fluidized bed gasification furnace 11 and processed, the calcium content closes the aeration nozzle. The problem of the clogging of the diffuser nozzle of the converter 11 does not occur.

  As described above, the preferred embodiment of the present invention has been described in detail. However, the present invention is not limited to the specific embodiment, and within the scope of the gist of the present invention described in the claims, Needless to say, various modifications and changes are possible.

DESCRIPTION OF SYMBOLS 10 Gasification furnace 12 Fluidized bed 15 Discharge chute 21 Melting furnace 26 Heat exchanger 41 Quenching tower 42 Waste liquid decomposition part 43 Quenching part 51 Bag filter 61 Neutralization tower 71 Mist cot rel 81 Extrusion

Claims (4)

By forming the fluidized bed with the air blown from the bottom side of the industrial waste thrown into the fluidized bed type gasification furnace, a part of the industrial waste is gasified by pyrolysis to recover incombustibles containing valuable metals In addition, in the operation method of the gasification melting furnace in which the pyrolysis gas generated in the gasification furnace and a part of the incombustible material transferred by the pyrolysis gas are processed in the melting furnace to generate slag,
A method for operating a gasification melting furnace, wherein dust containing calcium is slurried and blown into the melting furnace. In the operation method of the gasification melting furnace of Claim 1,
Slurry of the dust is a gasification characterized by removing chlorine by leaching water, removing the supernatant from the dechlorinated slurry by dehydration or decantation, and adding water to make a slurry liquid. How to operate the melting furnace. In the operation method of the gasification melting furnace of Claim 1 or 2,
The dust includes any one of dust collected from a quenching tower, dust collected by a bag filter, and dust collected from a neutralization tub that has been subjected to a wastewater treatment of a cleaning liquid in a neutralization tower or a mistcottrel. The operation method of the gasification melting furnace. In the operation method of the gasification melting furnace of Claim 2 or 3,
An operation method of a gasification melting furnace, wherein the slurry liquid is sprayed from the vicinity of the top of the melting furnace into the furnace.

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