JP2008275176A - Fluid bed-type combustion device using organic substance including chrome as fuel and detoxifying method of fly ash from fluid bed-type combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively efficiently detoxify fly ash by converting harmful hexavalent chromium in the fly ash discharged from the fluid bed-type combustion device using an organic substance including chrome as a fuel, into harmless trivalent chromium by performing reduction treatment of hexavalent chromium in a reactor vessel using a reduction gas extracted from a reduction combustion zone of a fluid bed furnace main body as a reactant without using an agent for treatment and large structural modification to the combustion device. <P>SOLUTION: In this fluid bed-type combustion device comprising the fluid bed furnace main body, a waste heat boiler recovering heat of the combustion exhaust gas from the fluid bed furnace main body, and a purifying device for purifying the combustion exhaust gas from the waste heat boiler, and using the organic substance including chromium as its fuel, the fly ash collected by the combustion exhaust gas purifying device is heated in the reactor vessel under reduction atmosphere, thus hexavalent chromium in the fly ash is reduced into trivalent chromium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluidized bed combustion apparatus using an organic substance containing chromium as a fuel, and a method for detoxifying fly ash discharged from the fluidized bed combustion apparatus, and adding chemicals or the like during combustion. Without damaging it, the fly ash collected by the exhaust gas purification device etc. is heated at a predetermined temperature or lower in the reactor in a reducing atmosphere, and harmful hexavalent chromium present in the fly ash is harmless to trivalent chromium. The present invention relates to a fluidized bed combustion apparatus using a chromium-containing organic substance as a fuel and a method for detoxifying fly ash discharged from the fluidized bed combustion apparatus.

Organic substances containing chromium such as bagasse and waste wood are attracting attention as energy sources from the viewpoint of effective utilization of so-called biomass energy.
However, woody biomass contains chromium, and it is a hazardous substance in the combustion residue discharged from combustion equipment such as boilers and waste incinerators that use organic matter containing these chromium as fuel. Hexavalent chromium is often included, and various problems arise when trying to preserve the environment.

  FIG. 2 shows an example of a known fluidized bed combustion apparatus K using an organic substance containing chromium as a fuel. In FIG. 2, 1 is a fluidized bed furnace body, 2 is a fluidized bed section (primary combustion zone). ) 3 is a free board section, 4 is a boiler section, 5 is a fuel supply device, 6 is a economizer, 7 is a multi-cyclone, 8 is a bag filter, 9 is a combustion air supply fan, 10 is an induction fan, 11 Is a chimney.

The organic substance containing chromium (hereinafter referred to as fuel) supplied to the fluidized bed portion 2 of the fluidized bed furnace body 1 is so-called fluidized in the fluidized bed portion 2 in which the fluidized bed is formed by the supply of the primary air A _1. After layer combustion (primary combustion), secondary combustion is performed by supplying secondary air A ₂ from the freeboard unit 3.
The combustion exhaust gas G from the freeboard section 3 is recovered by heat in the boiler section 4 and the economizer 6, and after removing fly ash and purifying the multicyclone 7 and the back filter 8, Goes away to.

  Depending on the fuel used, the boiler fly ash collected by the boiler unit 4, the multicyclone 7, the bag filter 8 and the like may contain a large amount of harmful heavy metals as described above. In particular, it has been found that chromium contained in a relatively safe form of trivalent chromium in an organic fuel containing chromium is oxidized by combustion and converted to harmful hexavalent chromium. The converted hexavalent chromium is contained in a relatively large amount in the fly ash collected by the bag filter 8. For example, if the total chromium weight in 1 kg of boiler fly ash collected by the bag filter 8 is 20 to 200 mg, 15 to 60% of the chromium is found to be hexavalent chromium.

Thus, in conventional combustion furnaces and combustion treatment furnaces that use organic materials containing chromium as the fuel, chemicals are added mainly to the discharged combustion residue and fly ash to remove hexavalent chromium and other harmful heavy metals. Removal processing is performed (Japanese Patent No. 3676768, Japanese Patent Laid-Open No. 2005-267331, Japanese Patent Laid-Open No. 2005-336128, etc.).
For example, in Japanese Patent No. 3676768, incineration ash containing a harmful heavy metal such as hexavalent chromium in the presence of an alkaline substance such as calcium oxide or magnesium oxide, an oxygen content of 1.5% or more and a temperature of 600 to 1000 ° C. The ash is rendered harmless by reacting twice in both high temperature ranges of one reaction zone and a second reaction zone having an oxygen content of 1.5% or less and a temperature of 500 to 1000 ° C. However, in the present invention, the incineration ash is detoxified by reacting twice in both high temperature ranges of 600 to 1000 ° C. and 500 to 1000 ° C., so that energy consumption is large and the border between the reaction zones is reduced. The equipment becomes complicated because it is necessary. In addition, since nitrogen gas is blown in the second reaction zone, there is a problem that energy consumption increases.

  Similarly, in Japanese Patent Laid-Open No. 2005-967331, incineration ash (fly ash) containing hexavalent chromium is treated with ferrous sulfate (reducing agent), and in Japanese Patent Laid-Open No. 2005-336128, 6 Incineration ash (fly ash) is made harmless by kneading and solidifying a chelating agent to fly ash containing harmful heavy metals such as valent chromium. However, the former requires a chemical (reducing agent), and the incinerated ash after treatment requires landfill disposal, and there is a problem that the ash cannot be effectively used. Moreover, the latter has a problem in the long-term stability of the containment to the chelate, and as a result, there is a difficulty that the effective use of ash is hindered.

  On the other hand, in order to solve the above-described problems in processing using chemicals, a technique for converting wood containing hexavalent chromium itself into a safe fuel resource (JP-A-2005-199112, etc.) and generation of hexavalent chromium Development of a combustion control method for waste (Japanese Patent Application Laid-Open No. 2005-321182, etc.) that suppresses the above is underway.

That is, in the former Japanese Patent Application Laid-Open No. 2005-199112, slaked lime is added to waste wood containing heavy metals such as copper, chromium and arsenic (CCA treatment agent) and heated in a reducing atmosphere to generate harmless carbides. As a result, it is recycled as charcoal.
However, converting waste wood into harmless charcoal requires considerable processing costs, so it is not economically comparable to using waste wood directly as fuel, and the charcoal generated from waste wood is not comparable. On the other hand, there is a problem that the demand itself is extremely small.

  Moreover, in the said Unexamined-Japanese-Patent No. 2005-321182, by improving the combustion method of the general waste (fuel) in a stoker type garbage combustion furnace, it is harmful from the harmless trivalent chromium compound contained in the fuel. The generation of the valent chromium compound during combustion is suppressed.

That is, it has been found that trivalent chromium contained in a large amount of waste (fuel) is oxidized into harmful hexavalent chromium by being exposed to a high temperature atmosphere for a long time.
Therefore, a characteristic graph as shown in FIG. 3 is created by investigating the relationship between the elution value of hexavalent chromium and the temperature and time in the dust layer on the stoker during combustion in advance by experiments. During operation of the stoker-type combustion furnace, the amount of waste input and the waste transfer speed are set so that the time integral value of the temperature in the dust layer is not more than the value corresponding to the allowable reference value of the hexavalent chromium elution value in FIG. And any one or more of the primary air supply amounts are adjusted.
The reference value for the elution value of hexavalent chromium in the incinerated ash is a value based on the so-called Environment Agency Notification No.13.

Since the technique disclosed in Japanese Patent Application Laid-Open No. 2005-321182 uses the detected value of the waste layer temperature on the stoker as a reference for control, accurate and stable detection of the waste layer temperature is indispensable.
However, waste on the stoker actually moves downstream on the stoker while performing complex movements, and the thickness of the waste layer varies greatly depending on the quality of the waste. It is extremely difficult to accurately detect the temperature. As a result, it is extremely difficult to stably operate a stoker-type incinerator in a state where the production of hexavalent chromium is controlled almost completely below the reference value, and there is a problem that it is practically impossible.

  In addition, in the stoker type incinerator, there is a considerable amount of combustion residue falling into the hopper below the stoker from the gap between the stokers during incineration, and the ash containing heavy metals such as hexavalent chromium extracted from the hopper below these stokers, It needs to be handled separately. Therefore, there is a problem that the hexavalent chromium cannot be effectively reduced with respect to all the incineration residues discharged only by the technique described in JP-A-2005-321182.

Japanese Patent No. 3676768 JP-A-2005-976731 JP-A-2005-336128 JP 2005-199112 A JP-A-2005-321182

  The present invention is a detoxification treatment of combustion residues discharged from a combustion furnace or combustion apparatus using an organic substance containing this kind of chromium as a fuel, particularly a removal treatment of harmful hexavalent chromium contained in fly ash. In the method for treating combustion residues using chemicals, not only the treatment cost and energy consumption increase, but also the effective utilization of ash is difficult. ) The method of detoxification by carbonizing waste wood, etc. is not economical and impractical. C) Heavy metals containing hexavalent chromium by improving the combustion method of organic fuel containing chromium. The method of suppressing the generation of ash is intended only for stoker-type combustion furnaces, and because it is difficult to accurately detect the combustion temperature in the waste layer, hexavalent chromium is stably reduced. While operating the combustion device In a fluidized bed combustion system using chromium-containing organic matter as fuel, the fly ash collected by the combustion exhaust gas purification treatment system is used to reduce the reaction in a reducing atmosphere. An organic substance containing chromium, which reduces harmful hexavalent chromium in fly ash to trivalent chromium at low cost and high efficiency by heating for a certain time at a predetermined temperature in a vessel. The present invention provides a fluidized bed combustion apparatus as a fuel and a detoxification method for fly ash discharged therefrom.

  Through the development of fluidized bed combustion furnaces over many years and the combustion tests using actual operating machines, the inventors of the present application have found that the chromium contained in the organic fuel containing chromium is contained in the form of trivalent chromium. It is converted into harmful hexavalent chromium by being oxidized during combustion, and in a general combustion temperature range of 700 ° C. to 1000 ° C., the higher the temperature, the more the production of hexavalent chromium is promoted. In addition, the production of hexavalent chromium is suppressed and the produced hexavalent chromium may be reduced to trivalent chromium, and once reduced, the reduced trivalent chromium is oxidized again. Therefore, it is desirable to maintain the reducing atmosphere temperature at 300 ° C. to 800 ° C. and to decompose organic chlorinated compounds such as dioxins, it is 800 Knowing that the combustion temperature above (desirably 850 ° C or higher for 2 seconds) is necessary, etc., and from that, fly ash in the combustion exhaust gas after complete combustion is captured by an exhaust gas purification device such as a bag filter. And by collecting the fly ash collected in a reactor maintained at a predetermined temperature and a reducing atmosphere using a reducing gas drawn out from the reducing combustion zone in the fluidized bed combustion furnace body. The idea was to convert hexavalent chromium in fly ash into harmless trivalent chromium efficiently and inexpensively.

  The present invention was created based on the above idea and the results of various tests using an actual operating furnace based on the above idea, and the invention of claim 1 is a fluidized bed furnace body and combustion from a fluidized bed furnace body. In a fluidized bed combustion apparatus using a chromium-containing organic material as a fuel, comprising a waste heat boiler that recovers the heat of exhaust gas, and a purification treatment device that purifies the combustion exhaust gas from the waste heat boiler, the purification of the combustion exhaust gas The basic configuration of the present invention is to reduce the hexavalent chromium in the fly ash to trivalent chromium by heating the fly ash collected by the treatment apparatus in a reactor in a reducing atmosphere.

  The invention of claim 2 is the invention of claim 1, wherein the temperature in the reactor is 300 to 800 ° C. and the oxygen concentration is 1.0% or less.

  The invention of claim 3 is the invention of claim 2, wherein the temperature of the reactor is set to 300 to 600 ° C. and the oxygen concentration is set to 1.0% or less.

  The invention of claim 4 is the reducing gas after reducing the air ratio in the reducing combustion zone of the fluidized bed furnace main body to 1.0 or less and reducing and burning in the reducing combustion zone in the invention of claim 1 or claim 2. Is drawn out and blown into the reactor at an oxygen concentration of 1.0% or less.

  According to a fifth aspect of the present invention, in the invention of the fourth aspect, the air ratio of the reducing combustion zone of the fluidized bed furnace main body is set to 0.8 to 0.95, and the reducing gas after being reduced and burned in the reducing combustion zone is drawn out. The oxygen concentration is not more than 1.0% and is blown into the reactor.

  The invention according to claim 6 is the invention according to claim 1, claim 2, claim 3, claim 4 or claim 5, wherein the treated ash reacted with the reducing gas in the reactor for 30 minutes or more and the reactor. This is a cooler that rapidly cools ash collected by a filter device that purifies the exhaust gas to 180 ° C. or lower.

  The invention according to claim 7 is a fluidized bed furnace body using an organic substance containing chromium as a fuel, a waste heat boiler for recovering heat of combustion exhaust gas from the fluidized bed furnace body, and purifying the exhaust gas from the waste heat boiler. An exhaust gas purifier, and a reactor that converts the fly ash collected by the exhaust gas purifier and the reducing gas extracted from the reduction combustion zone of the fluidized bed furnace body to convert hexavalent chromium in the fly ash into trivalent chromium; A filter device for purifying the exhaust gas from the reactor, a cooler for cooling the treated ash from the reactor and the separated ash from the filter device, and a fluidized bed by mixing air with the exhaust gas from the filter device The basic structure of the present invention is to make harmless by reducing hexavalent chromium in fly ash to trivalent chromium, comprising a mixer for forming a mixed gas to be supplied to the oxidation combustion zone above the reduction combustion zone of the furnace body With what That.

  The invention according to claim 8 is the invention according to claim 7, wherein the fluidized bed furnace body is provided with a secondary reduction combustion zone and an oxidation combustion zone, and the air ratio of the reduction combustion zone is 0.8 to 0.95. This is a fluidized bed furnace body having an air ratio of 1.4 or less.

  The invention of claim 9 is the invention according to claim 7, wherein the reactor is a reactor having an oxygen concentration of 1% or less, a heating temperature of 300 to 800 ° C., and a fly ash residence time of 30 minutes or more. It is a thing.

  The invention of claim 10 is the cooler according to claim 7, wherein the reactor has an oxygen concentration of 1% or less, a heating temperature of 300 ° C. to 600 ° C., and a fly ash residence time of 30 minutes or more. It is what.

  The invention of claim 11 is the cooling of the structure according to claim 7 or claim 8, wherein the cooler rapidly cools the treated ash and the ash collected by the filter device to a temperature of 180 ° C. or less in a reducing atmosphere. It is a container.

  The invention of claim 12 is the invention of claim 7, 8 or 11, wherein the mixer is a mixer configured to form a mixed gas of 300 ° C. or lower.

  In the invention of claim 1 of the present application, in a fluidized bed combustion apparatus using an organic substance containing chromium as a fuel, the reduction of fly ash collected by an exhaust gas purification treatment apparatus or the like from the reduction combustion zone of the fluidized bed furnace body By reducing the gas in the reactor that supplies gas, harmful hexavalent chromium in the fly ash can be reliably converted into harmless trivalent chromium, and the elution amount of hexavalent chromium is regulated. The following can be maintained.

  In the inventions of claims 2 to 5, the reduction of hexavalent chromium in the reactor to trivalent chromium is more efficiently performed, and the processing time can be shortened and the processing level can be greatly improved. It becomes.

  In the invention of claim 6 of the present application, trivalent chromium once reduced from hexavalent chromium is almost never converted again to hexavalent chromium, and safer processed fly ash is stored in the fly ash silo. be able to.

  In the invention described in claim 7, the hexavalent chromium contained in the fly ash in the combustion exhaust gas is reduced to trivalent chromium without any significant structural modification to the fluidized bed combustion apparatus. Therefore, more efficient fly ash detoxification is possible.

In the inventions of claims 8 to 12, the fly ash is heated in a reactor under the conditions of 300 to 800 ° C. or 300 ° C. to 600 ° C. and an oxygen concentration of 1.0% or less. The produced hexavalent chromium is efficiently reduced to trivalent chromium, which makes it possible to satisfy the elution standard of hexavalent chromium.
In addition, by using the reducing gas extracted from the reducing zone of the fluidized bed furnace body as the reducing gas of the reactor, a reducing atmosphere can be formed without blowing nitrogen or the like into the reactor, and the running cost is reduced. Significant reduction is possible. Furthermore, it is possible to prevent trivalent chromium from being converted to hexavalent chromium by quenching the treated ash from the reactor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system configuration diagram of a fluidized bed combustion apparatus according to the present invention. The difference from the conventional fluidized bed combustion furnace shown in FIG. 2 is that the reducing gas from the reducing combustion zone 2 in the fluidized bed furnace body 1 is reduced. G ₁ is extracted and supplied into the reactor 15 where the fly ash C ₁ from the exhaust gas treatment device 8 is reduced at a constant temperature, and the exhaust gas G ₂ from the reactor 15 is filtered. 16, and a mixture gas A ₃ formed by mixing fresh air A ₂ with the mixer 17 is supplied to the combustion zone (oxidation combustion zone) 3 as combustion air, and the reactor 15. The processed fly ash C _{2 and the} like from the above are rapidly cooled by the cooler 18 and then recovered to the fly ash silo 19.
In FIG. 1, the same reference numerals are used for the same parts and members as in FIG.

With reference to FIG. 1, the organic fuel containing chip-like chromium supplied from the fuel supply device 5 is supplied to the fluidized bed portion 2 forming the fluidized bed by blowing the primary air A ₁ .
The supply amount of the primary air A ₁ to the fluidized bed portion 2 is controlled to be 1.0 or less (preferably 0.8 to 0.95) in terms of the air ratio. mixed total air ratio, including the fresh air a ₂ for combustion is controlled to 1.4 or less. Thus, the fluidized bed portion 2 forms a reduction zone, and the supplied organic fuel containing chromium is so-called reduction combustion.

Further, the combustion temperature of the fluidized bed portion 2 is controlled to 950 ° C. or less by controlling the fuel supply amount and the primary air A ₁ supply amount. (More desirably, 850 to 900 ° C.). The reason why the combustion temperature in the fluidized bed 2 is set to 300 ° C. to 800 ° C. is that the material converted from hexavalent chromium to trivalent chromium under reducing combustion is oxidized again and converted to hexavalent chromium. This is to prevent it.
By so-called reductive combustion of the combustion gas in the fluidized bed portion 2, combustion of combustible substances in the combustion exhaust gas is performed while suppressing generation of harmful substances such as dioxin and NOx and conversion to hexavalent chromium.

The combustion gas from the fluidized bed portion 2 is continuously guided to the free board portion 3, where the mixed gas A ₃ is blown from the combustion air supply fan 13, whereby 800 to 860 ° C. (preferably 850 ° C.). As described above, oxidation combustion is performed at a relatively low temperature for 2 seconds, and unburned matter in the combustion gas is completely burned.

  Specifically, it is desirable that the combustion in the free board part 3 is carried out at an oxygen concentration of 4.0 to 6.0% and a combustion temperature of 800 to 860 ° C., whereby organic chlorine compounds such as dioxin are also decomposed. Will be.

The combustion gas G that has exited the freeboard section 3 is recovered by the boiler section 4 and then discharged into the atmosphere through an exhaust gas purification treatment device (bag filter) 8 and an induction fan 10.
Moreover, the combustion temperature and oxygen concentration in the fluidized bed portion 2 and the freeboard portion 3 are continuously measured by temperature detectors T _{1 to} T _{2 such as} thermocouples and laser type oxygen concentration detectors O _{1 to} O ₂ . Is input to the combustion control F.
Furthermore, from the combustion control device F driver of the fuel supply device 5, a control signal to the drive unit of the drive unit and the control damper D ₁ to D ₄ of each fan 9, 10, 13 are output.

The reactor 15 includes a fly ash C ₁ from the exhaust gas purifying apparatus 8, the fluidized bed of the fluidized-bed furnace body 1 is brought into contact with a reducing gas G ₁ was withdrawn from (reducing combustion zone) 2, fly ash C ₁ Among these, hexavalent chromium is reduced to trivalent chromium. In this embodiment, a so-called fixed bed reactor 15 is used. Of course, the reactor 15 may be a kiln type or fluidized bed type reactor as long as the reducing gas G ₁ and the fly ash C ₁ can be sufficiently brought into contact with each other. .

The oxygen concentration of the atmosphere in the reactor 15 is maintained at 1% or less, and the temperature is maintained at 300 to 800 ° C. (preferably 300 to 600 ° C.). Furthermore, the contact time (reaction time) between the fly ash and the reducing gas G ₁ is about 30 minutes or more.

The heating temperature in the reactor 15 is 300 to 800 ° C. As described above, reduction from hexavalent chromium to trivalent chromium is efficiently performed by the reducing gas G ₁ and conversion from trivalent chromium to hexavalent chromium is performed. It is a temperature determined from the point that it can be suppressed.
Further, when the oxygen concentration of the reducing gas G ₁ extracted from the fluidized bed portion (reducing combustion zone) 2 of the fluidized bed furnace body 1 exceeds 1%, the O ₂ concentration is adjusted by mixing N ₂ gas or the like. The
Furthermore, in the embodiment of FIG. 1, only the collected fly ash C ₁ from the exhaust gas treatment device 8 is supplied to the reactor 10, but it is captured in the boiler unit 4 and other exhaust gas treatment units (not shown). Of course, the collected fly ash may be supplied to the reactor 15 together.

The filter device 16 purifies the exhaust gas (reducing gas G ₂ ) from the reactor 15. The reducing gas G ₃ after removing the mixed fly ash C ₃ is sent to the mixer 17 where it is oxidized. By mixing the fresh air A ₂ for combustion, a mixed gas A ₃ of 300 ° C. or lower is formed. In this embodiment, a ceramic filter is used as the filter device 16.
The mixed gas A ₃ formed in the mixer 17 is supplied to the free board portion (oxidation combustion zone) 3 of the fluidized bed furnace body 1 through the air supply line 14, and the free board portion (oxidation combustion zone). 3), oxidation combustion is performed at a temperature of about 800 ° C. to 860 ° C.

The treated ash C ₂ reduced in the reactor 15 and the separated ash C ₃ separated by the filter device 16 are introduced into the cooler 18 while being maintained in a reducing atmosphere, where 180 ° C. Quenched to the following temperature. By the rapid cooling operation in the reduced state in the cooler 18, the trivalent chromium formed by the reduction of hexavalent chromium is recovered in the fly ash silo 19 without being converted again to hexavalent chromium. It will be.

The present invention can be applied not only to a fluidized bed combustion apparatus but also to various fluidized bed combustion furnaces and boilers.
The present invention can also be applied to a stoker-type combustion furnace or the like.

1 is a configuration system diagram showing an example of a fluidized bed combustion apparatus used in the practice of the present invention. 1 shows an example of a fluidized bed combustion apparatus using a conventional organic material containing chromium as a fuel. It is a diagram which shows the relationship between the elution amount of hexavalent chromium from the incineration residue of Unexamined-Japanese-Patent No. 2005-321182, and the time integral value of the maximum temperature in a waste layer.

Explanation of symbols

E ・ ・ Fluidized bed type combustor C _{1 to} C ₄・ ・ Fly ash A ₁・ ・ Primary combustion air A ₂・ ・ Fresh air (for tertiary combustion)
A ₃・ ・ Mixed gas (Air for tertiary combustion)
G ·· Combustion exhaust gas G ₁ ·· Reducing gas G ₂ ·· Reactor exit exhaust gas G ₃ ·· Filter device exit exhaust gas O _{1 to} O ₂ ·· Oxygen concentration detector F ·· Combustion control device D _{1 to} D ₅ ·・ Control dampers T _{1 to} T ₂・ ・ Temperature detector 1 ・ ・ Fluidized bed furnace body 2 ・ ・ Fluidized bed (reduction combustion zone)
3. Free board section (oxidation combustion zone)
4. Boiler section 5. Fuel supply device 8. Exhaust gas purification device 9. Combustion air supply fan 10. Induction fan 11. Chimney 12. Reducing gas extraction line 13. Combustion air supply fan 14. Air supply line

15. · Reactor 16 · · Filter device 17 · · Mixer 18 · · Cooler 19 · · Fly ash silo

Claims (12)

  A fluidized bed furnace body, a waste heat boiler that recovers the heat of combustion exhaust gas from the fluidized bed furnace body, and a purification treatment device that purifies the combustion exhaust gas from the waste heat boiler, and containing chromium-containing organic matter as fuel In the fluidized bed combustion apparatus, the hexavalent chromium in the fly ash is reduced to trivalent chromium by heating the fly ash collected by the combustion exhaust gas purification treatment apparatus in a reactor in a reducing atmosphere. A method for detoxifying fly ash from a fluidized bed combustor using an organic substance containing chromium as a fuel.   The temperature of the reactor is set to 300 to 800 ° C., and the oxygen concentration is set to 1.0% or less. Detoxification treatment method.   The harmlessness of fly ash from a fluidized bed combustor using a chromium-containing organic material as a fuel according to claim 2, wherein the temperature in the reactor is 300 to 600 ° C and the oxygen concentration is 1.0% or less. Processing method.   The air ratio in the reduction combustion zone of the fluidized bed furnace main body is set to 1.0 or less, and the reducing gas after reduction combustion in the secondary reduction combustion zone is drawn out and blown into the reactor with an oxygen concentration of 1.0% or less. A method for detoxifying fly ash from a fluidized bed combustion apparatus using the chromium-containing organic matter according to claim 1, claim 2 or claim 3 as fuel.   The air ratio in the reducing combustion zone of the fluidized bed furnace body is set to 0.8 to 0.95 and the reducing gas after reducing combustion in the reducing combustion zone is drawn out and blown into the reactor with an oxygen concentration of 1.0% or less. The detoxification processing method of the fly ash from the fluidized-bed combustion apparatus which uses the organic substance containing chromium of Claim 4 as a fuel.   The cooler was a cooler that rapidly cooled the treated ash reacted with the reducing gas in the reactor for 30 minutes or more and the ash collected by the filter device for purifying the exhaust gas from the reactor to 180 ° C. or lower. A method for detoxifying fly ash from a fluidized-bed combustion apparatus using the organic material containing chromium according to claim 1, claim 2, claim 3, claim 4 or claim 5 as fuel.   Fluidized bed furnace main body using organic matter containing chromium as fuel, waste heat boiler that recovers heat of combustion exhaust gas from fluidized bed furnace main body, exhaust gas purification device that purifies exhaust gas from waste heat boiler, and exhaust gas purification A reactor for supplying fly ash collected by the apparatus and a reducing gas withdrawn from the reduction combustion zone of the fluidized bed furnace body to convert hexavalent chromium in the fly ash to trivalent chromium, and exhaust gas from the reactor A filter device for purification, a cooler for cooling the treated ash from the reactor and the ash collected by the filter device, and reducing combustion of the fluidized bed furnace body by mixing air with the exhaust gas from the filter device Containing chromium characterized in that it consists of a mixer that forms a mixed gas to be supplied to the oxidation combustion zone above the zone, and is made harmless by reducing hexavalent chromium in fly ash to trivalent chromium Organic matter Fluidized bed combustion device used as fuel.   A fluidized bed having a fluidized bed furnace body having a reduction combustion zone and an oxidation combustion zone, wherein the air ratio of the reduction combustion zone is 0.8 to 0.95, and the total air ratio is 1.4 or less. A fluidized bed combustor using a chromium-containing organic substance as claimed in claim 7 as a furnace body.   8. The organic material containing chromium according to claim 7, wherein the reactor is a reactor having an oxygen concentration of 1% or less, a heating temperature of 300 to 800 ° C., and a fly ash residence time of 30 minutes or more. Fluidized bed combustion device.   The chromium-containing organic substance according to claim 7, wherein the reactor is a reactor having an oxygen concentration of 1% or less, a heating temperature of 300 ° C. to 600 ° C., and a fly ash residence time of 30 minutes or more. Fluidized bed combustion device used as fuel.   The organic substance containing chromium according to claim 7 or 8, wherein the cooler is a cooler configured to rapidly cool treated ash and ash collected by a filter device to a temperature of 180 ° C or lower in a reducing atmosphere. Fluidized bed combustor using as fuel.   The fluidized-bed combustion apparatus using the organic substance containing chromium as a fuel according to claim 7, wherein the mixer is configured to form a mixed gas of 300 ° C. or less.

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