JP4966940B2 - Fly ash treatment apparatus, fly ash treatment method, waste treatment system, and operation method of waste treatment system - Google Patents

Description

  The present invention includes a fly ash treatment apparatus, a fly ash treatment method, and the fly ash treatment apparatus that suppress elution of heavy metals, particularly hexavalent chromium (Cr (VI)), from fly ash generated in a waste treatment system. The present invention relates to a waste disposal system and a method for operating the waste disposal system.

  The exhaust gas generated when the waste is gasified and melted in the waste treatment system contains fly ash. This fly ash is generally rich in heavy metals. For this reason, when landfill disposal of fly ash is concerned, there is concern that the environment will be polluted by heavy metals eluted from fly ash, and in particular, lead (Pb), hexavalent chromium (Cr (VI)), cadmium (Cd ), Mercury (Hg), arsenic (As), and selenium (Se) are provided with elution standard values (announcement No. 13) for landfill disposal. It is required to perform a detoxification treatment such as preventing elution of heavy metals.

  Therefore, as a detoxification method of fly ash for preventing heavy metals in fly ash from eluting, for example, heavy metals for preventing elution of heavy metals by immobilizing heavy metals or the like For example, an elution preventing agent may be added to fly ash and kneaded. Specifically, first, fly ash in the exhaust gas is collected by a dust collector such as a bag filter. The collected fly ash is transported to a fly ash storage tank by a fly ash transport conveyor or the like. Then, a certain amount of fly ash is cut out from the fly ash storage tank, and this and a certain amount of heavy metal elution preventing agent are kneaded by a kneader. By doing so, elution of heavy metals from fly ash was suppressed.

  However, the amount of heavy metal elution prevention chemicals required to suppress elution of heavy metals varies depending on the properties of the waste that is put into the gasification melting furnace, so from the viewpoint of preventing elution of heavy metals, There was a problem that a large amount of preventive drug had to be supplied. According to such a method, it is difficult to reduce costs.

Therefore, as a method for solving this, for example, a method described in Patent Document 1 can be cited. In the following Patent Document 1, in a method of adding a liquid chelating agent having a dithiocarbamic acid group (heavy metal dissolution preventing agent) to fly ash and treating it, the concentrations of Pb and Cu in the fly ash are measured, and these measurements are made. A method for determining the required amount of liquid chelating agent for fly ash treatment, which determines the amount of liquid chelating agent to be added to the fly ash from the value and the dithiocarbamate group concentration in the liquid chelating agent is described Yes.
Japanese Patent Application Laid-Open No. 11-70374

  As a method to suppress elution of heavy metals from fly ash by adding a heavy metal elution prevention agent to fly ash and kneading, as described above, prevention of heavy metal elution is necessary. The question is how to determine the appropriate supply of drug.

  Patent Document 1 discloses that by analyzing the Pb and Cu content concentrations in fly ash, it is possible to determine the supply amount of the heavy metal elution preventing agent necessary for immobilization of Pb and Cu. However, Cr (VI) exists as an important heavy metal that must be prevented from elution, but no quantification of a heavy metal elution preventing drug for that purpose has been proposed.

  The present invention can appropriately and quickly estimate the supply amount of a heavy metal elution preventing agent capable of suppressing elution of heavy metals, particularly Cr (VI) from fly ash in a waste treatment system, and a large amount of heavy metal elution preventing agent can be estimated. Provided is a fly ash treatment device, a fly ash treatment method, a waste treatment system equipped with the fly ash treatment device, and a method for operating the waste treatment system, which can easily detoxify fly ash without supplying it. The purpose is to do.

The Cr content of Cr (VI) and other valence Cr can be measured by using a fluorescent X-ray analyzer, but the content of Cr (VI) alone is the fluorescence X It was difficult to measure using a line analyzer. However, the present inventors paid attention to the fact that the ratio of the Cr (VI) elution amount to the Cr content is correlated with the pH of the eluate, and the heavy metal elution preventing agent for preventing the elution of Cr (VI) To achieve quantification. That is, the fly ash treatment apparatus according to one aspect of the present invention includes a gasification melting furnace that thermally decomposes the input waste and melts ash in the pyrolysis gas generated by the thermal decomposition to slag. A fly ash treatment device for suppressing elution of heavy metals from fly ash contained in a molten exhaust gas discharged from the gasification melting furnace and collected by dust collecting means, provided in a material treatment system A kneading means for supplying and kneading a heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash to the fly ash, Cr content measuring means for measuring the total chromium (Cr) content, pH measuring means for measuring the pH of the eluate from the fly ash, and Cr (VI) for the pH and Cr content of the eluate prepared in advance. Measure based on the correlation with the elution volume ratio. Calculate the expected amount of Cr (VI) elution from the fly ash by calculating the ratio of Cr (VI) elution to the Cr content at pH and multiplying the calculated ratio by the measured Cr content. And calculating means for calculating the supply amount of the Cr (VI) heavy metal elution preventing agent capable of preventing the elution of Cr (VI) based on the predicted value as a target value, and the heavy metal for Cr (VI) A supply amount adjusting means for adjusting the supply amount of the elution preventing chemical so as to be the target value, wherein the Cr content measuring means is an X-ray fluorescence analyzer.

  According to the said structure, the heavy metal elution prevention chemical | medical agent for Cr (VI) which can prevent the elution of harmful Cr (VI) by measuring Cr content in fly ash and pH of the eluate from fly ash Can be appropriately estimated as the target value. Moreover, since Cr content in fly ash is measured using a fluorescent X ray analyzer, it can carry out rapidly. Then, by adjusting the supply amount of the heavy metal elution preventing agent for Cr (VI) so as to be the target value, harmful Cr (VI) is not supplied without supplying a large amount of the heavy metal elution preventing agent for Cr (VI). Elution can be suppressed.

  From the above, in the waste treatment system, the supply amount of the heavy metal elution preventing agent for Cr (VI) capable of suppressing elution from the fly ash of Cr (VI), which is a heavy metal, can be estimated appropriately and quickly. Fly ash can be easily detoxified without supplying a large amount of the heavy metal elution preventing agent for Cr (VI).

A fly ash treatment apparatus according to another aspect of the present invention is a waste provided with a gasification melting furnace that pyrolyzes waste to be charged and melts ash in pyrolysis gas generated by the thermal decomposition to slag. A fly ash treatment device for suppressing elution of heavy metals from fly ash contained in a molten exhaust gas discharged from the gasification melting furnace and collected by dust collecting means, provided in a material treatment system , A heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash, for Pb for preventing elution of lead (Pb) in the fly ash A kneading means for supplying and kneading the heavy metal elution preventing agent to the fly ash, a heavy metal content measuring means for measuring each content of total chromium (Cr), copper (Cu) and Pb in the fly ash, and Prepared in advance with pH measuring means for measuring pH of eluate from fly ash Based on the correlation between the pH of the eluate and the ratio of the Cr (VI) elution amount to the Cr content, the ratio of the Cr (VI) elution amount to the Cr content at the measured pH was calculated, and the calculated ratio Is multiplied by the measured value of Cr content to calculate the expected value of Cr (VI) elution from the fly ash, and based on the expected value of Cr (VI) elution, Cr (VI) First calculating means for calculating the supply amount of the heavy metal dissolution preventing agent for Cr (VI) capable of preventing elution as a first target value; and the supply amount of the heavy metal dissolution preventing agent for Cr (VI) as the first target. Based on the correlation between the first supply amount adjusting means that adjusts to a value and the Pb and Cu contents prepared in advance and the elution amounts of Pb and Cu, the measured values of the Pb and Cu contents Dissolution of Pb and Cu from fly ash The amount of the Pb heavy metal elution preventing agent capable of preventing the elution of Pb regardless of the content of Cu is calculated based on the expected value of the elution amount of Pb and Cu. 2nd calculating means for calculating as 2 target values, and 2nd supply amount adjusting means for adjusting the supply amount of the Pb heavy metal elution preventing medicine to be the second target value, the heavy metal content measuring means Is a fluorescent X-ray analyzer.

  According to the above configuration, first of all, elution of heavy metals for Cr (VI) can prevent harmful Cr (VI) elution by measuring the Cr content in the fly ash and the pH of the eluate from the fly ash. The supply amount of the preventive drug can be appropriately estimated as the first target value. Moreover, since Cr content in fly ash is measured using a fluorescent X ray analyzer, it can carry out rapidly. Then, by adjusting the supply amount of the heavy metal elution preventing agent for Cr (VI) so as to be the first target value, a harmful Cr (VI) is supplied without supplying a large amount of the heavy metal elution preventing agent for Cr (VI). The elution of VI) can be suppressed.

  Then, by measuring the contents of Pb and Cu in the fly ash, the supply amount of the heavy metal elution preventing agent for Pb for suppressing harmful Pb from the fly ash regardless of the Cu content. Can be appropriately estimated as the second target value. Moreover, since the content of Pb and Cu in the fly ash is measured using a fluorescent X-ray analyzer in the same manner as described above, it can be performed quickly. By adjusting the supply amount of the heavy metal elution preventing agent for Pb so as to be the second target value, harmful elution of Pb can be suppressed without supplying a large amount of the heavy metal elution preventing agent for Pb. it can.

  From the above, in the waste treatment system, each of the heavy metal elution preventing agent for Cr (VI) and the heavy metal elution preventing agent for Pb capable of suppressing elution of heavy metals Pb, Cu, and Cr from fly ash The supply amount can be estimated appropriately and quickly, and fly ash can be easily detoxified without supplying a large amount of both the heavy metal dissolution preventing agent for Cr (VI) and the heavy metal dissolution preventing agent for Pb.

A waste treatment system according to another aspect of the present invention includes a gasification melting furnace that thermally decomposes waste to be charged and melts ash in the pyrolysis gas generated by the thermal decomposition to slag. A waste disposal system for adjusting the basicity (CaO / SiO ₂ ) of slag discharged from the slag discharge port to a position upstream of the slag discharge port for discharging the slag out of the furnace Basicity adjusting agent supplying means for supplying a basicity adjusting agent, basicity measuring means for measuring the basicity of the slag, and the measured basicity so as to be a target value of preset basicity A basicity adjusting agent supply amount adjusting means for adjusting a supply amount of the basicity adjusting agent; and the fly ash treatment apparatus, wherein the basicity measurement means includes the fluorescent X-ray analyzer in the fly ash treatment apparatus. , X-ray fluorescence analyzer Thus, the content of calcium in said slag (Ca) each content of silicon (Si) were measured, calcium oxide from the content of the Ca and Si and (CaO) and silicon dioxide (SiO ₂₎ It has a means to calculate each quantity and to calculate the basicity from the calculation result.

As described above, when waste is gasified and melted and slag is discharged from the melting furnace, in order to facilitate the discharge of slag from the melting furnace, the melting point and melting point of the slag formed in the melting furnace. It is desirable that the pour point is low. And it is known that the melting point or melting point of this slag depends on the mass ratio (basicity) of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) of the slag. As a method of adjusting the basicity of the slag is generally basicity adjusting agent such as silica sand composed mainly of SiO ₂ is supplied. However, the supply amount was often a part depending on experience or a large amount.

So, according to the said structure, each content of the calcium (Ca) and silicon (Si) in the said slag is measured with the fluorescent X-ray-analysis apparatus in the said fly ash processing apparatus, respectively, The said Ca and Si From each content, the content of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) can be calculated, and the basicity can be calculated from the calculation result. And the appropriate supply amount of a basicity adjusting agent is estimated based on the measured value of the basicity of this slag.

  From the above, by using the fluorescent X-ray analyzer in the fly ash treatment apparatus, it is possible not only to quickly estimate the appropriate supply amount of the heavy metal elution preventing chemical supplied to the fly ash, but also to supply the slag. An appropriate supply amount of the basicity adjusting agent can also be quickly estimated.

A fly ash treatment method according to another aspect of the present invention includes a gasification melting furnace for pyrolyzing waste to be charged and melting ash in pyrolysis gas generated by the thermal decomposition to slag. Upon operating the goods processing system, there by fly ash treatment method for inhibiting the elution of heavy metals from fly ash, which is collected by the included precipitator unit during the melting exhaust gas discharged from the gasification melting furnace A kneading step of supplying and kneading a heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash to the fly ash; A Cr content measurement step for measuring the total chromium (Cr) content of the sample, a pH measurement step for measuring the pH of the eluate from the fly ash, and a Cr (VI for the pH and Cr content of the eluate prepared in advance. ) Measured based on correlation with elution volume ratio By calculating the ratio of Cr (VI) elution amount to Cr content at different pH and multiplying the calculated ratio by the measured value of Cr content, the expected value of Cr (VI) elution amount from the fly ash is calculated. A calculation step of calculating, as a target value, a supply amount of the heavy metal elution preventing agent for Cr (VI) capable of preventing elution of Cr (VI) based on the predicted value; and for the Cr (VI) A supply amount adjusting step of adjusting the supply amount of the heavy metal elution preventing chemical so as to be the target value, and the Cr content measuring step uses a fluorescent X-ray analyzer.

  According to the said structure, the heavy metal elution prevention chemical | medical agent for Cr (VI) which can prevent the elution of harmful Cr (VI) by measuring Cr content in fly ash and pH of the eluate from fly ash Can be appropriately estimated as the target value. Moreover, since Cr content in fly ash is measured using a fluorescent X ray analyzer, it can carry out rapidly. Then, by adjusting the supply amount of the heavy metal elution preventing agent for Cr (VI) so as to be the target value, harmful Cr (VI) is not supplied without supplying a large amount of the heavy metal elution preventing agent for Cr (VI). Elution can be suppressed.

  From the above, in the waste treatment system, the supply amount of the heavy metal elution preventing agent for Cr (VI) capable of suppressing elution from the fly ash of Cr (VI), which is a heavy metal, can be estimated appropriately and quickly. Fly ash can be easily detoxified without supplying a large amount of the heavy metal elution preventing agent for Cr (VI).

A fly ash treatment method according to another aspect of the present invention includes a gasification melting furnace for pyrolyzing waste to be charged and melting ash in pyrolysis gas generated by the thermal decomposition to slag. Upon operating the goods processing system, there by fly ash treatment method for inhibiting the elution of heavy metals from fly ash, which is collected by the included precipitator unit during the melting exhaust gas discharged from the gasification melting furnace In addition, a heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash, and Pb for preventing elution of lead (Pb) in the fly ash A kneading step for supplying and kneading the heavy metal elution preventing agent for the fly ash, a heavy metal content measuring step for measuring each content of total chromium (Cr), copper (Cu) and Pb in the fly ash, A pH measurement step for measuring the pH of the eluate from the fly ash; Based on the correlation between the pH of the prepared eluate and the ratio of the Cr (VI) elution amount to the Cr content, the ratio of the Cr (VI) elution amount to the Cr content at the measured pH is calculated and calculated. By multiplying the measured ratio of Cr content by the measured value of Cr content, the expected value of Cr (VI) elution amount from the fly ash is calculated, and Cr (VI) is calculated based on the expected value of Cr (VI) elution amount. ) To calculate the supply amount of the Cr (VI) heavy metal elution prevention agent as a first target value, and the supply amount of the Cr (VI) heavy metal elution prevention agent to the first target value. Based on the correlation between the first supply amount adjusting step for adjusting to one target value and the Pb and Cu content prepared in advance and the elution amount of Pb and Cu, the measured value of the Pb and Cu content To Pb from the fly ash and The supply amount of the heavy metal elution preventing agent for Pb that can calculate the expected value of the elution amount of u and can prevent the elution of Pb regardless of the Cu content based on the expected value of the elution amount of Pb and Cu The second target value, and a second supply amount adjusting step for adjusting the supply amount of the Pb heavy metal elution preventing chemical so as to be the second target value, the heavy metal containing The quantity measuring step uses an X-ray fluorescence analyzer.

  According to the above configuration, first of all, elution of heavy metals for Cr (VI) can prevent harmful Cr (VI) elution by measuring the Cr content in the fly ash and the pH of the eluate from the fly ash. The supply amount of the preventive drug can be appropriately estimated as the first target value. Moreover, since Cr content in fly ash is measured using a fluorescent X ray analyzer, it can carry out rapidly. Then, by adjusting the supply amount of the heavy metal elution preventing agent for Cr (VI) so as to be the first target value, a harmful Cr (VI) is supplied without supplying a large amount of the heavy metal elution preventing agent for Cr (VI). The elution of VI) can be suppressed.

  Then, by measuring the contents of Pb and Cu in the fly ash, the supply amount of the heavy metal elution preventing agent for Pb for suppressing harmful Pb from the fly ash regardless of the Cu content. Can be appropriately estimated as the second target value. Moreover, since the content of Pb and Cu in the fly ash is measured using a fluorescent X-ray analyzer in the same manner as described above, it can be performed quickly. By adjusting the supply amount of the heavy metal elution preventing agent for Pb so as to be the second target value, harmful elution of Pb can be suppressed without supplying a large amount of the heavy metal elution preventing agent for Pb. it can.

  From the above, in the waste treatment system, each of the heavy metal elution preventing agent for Cr (VI) and the heavy metal elution preventing agent for Pb capable of suppressing elution of heavy metals Pb, Cu, and Cr from fly ash The supply amount can be estimated appropriately and quickly, and fly ash can be easily detoxified without supplying a large amount of both the heavy metal dissolution preventing agent for Cr (VI) and the heavy metal dissolution preventing agent for Pb.

A method for operating a waste treatment system according to another aspect of the present invention includes a gasification melting furnace that thermally decomposes waste to be charged and melts ash in pyrolysis gas generated by the thermal decomposition to slag. A waste treatment system comprising: a basicity of slag discharged from the slag discharge port at a position upstream of a slag discharge port for discharging the slag out of the furnace (CaO / SiO _2). ), A basicity adjusting agent supplying step for supplying a basicity adjusting agent to adjust the basicity of the slag, a basicity measuring step for measuring the basicity of the slag, and the measured basicity as a target of preset basicity A basicity adjusting agent supply amount adjusting step for adjusting the supply amount of the basicity adjusting agent to be a value, and a fly ash treatment step for suppressing elution of heavy metals from fly ash by the fly ash treatment method, The basicity measurement step Using the X-ray fluorescence analyzer in the fly ash treatment step, each content of calcium (Ca) and silicon (Si) in the slag is measured, and calcium oxide is calculated from each content of Ca and Si. (CaO) and a content of silicon dioxide (SiO ₂₎ was calculated, and is characterized in further comprising the step of calculating the basicity of the calculation result.

According to the said structure, each content of the calcium (Ca) and silicon (Si) in the said slag is measured with the fluorescent X-ray-analysis apparatus in the said fly ash treatment process, respectively, Each content of the said Ca and Si The contents of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) can be calculated from the amounts, and the basicity can be calculated from the calculation results. And the appropriate supply amount of a basicity adjusting agent is estimated based on the measured value of the basicity of this slag.

  From the above, by using the fluorescent X-ray analyzer in the fly ash treatment step, it is possible not only to quickly estimate an appropriate supply amount of the heavy metal elution preventing agent supplied to the fly ash, but also to the slag. An appropriate supply amount of the basicity adjusting agent can also be quickly estimated.

  According to the present invention, in a waste treatment system, it is possible to appropriately and quickly estimate the supply amount of a heavy metal elution preventing agent capable of suppressing elution of heavy metals, particularly Cr (VI), from fly ash. Fly ash treatment apparatus, fly ash treatment method, waste treatment system equipped with the fly ash treatment apparatus, and operation method of the waste treatment system, capable of easily detoxifying fly ash without supplying a large amount Can be provided.

  FIG. 1 is a schematic diagram showing the overall configuration of a waste treatment system according to an embodiment of the present invention. The waste treatment system includes a gasification melting furnace 20, a waste supply unit 10 that supplies waste as waste to the gasification melting furnace 20, and molten exhaust gas discharged from the gasification melting furnace 20. Exhaust gas treatment unit 30 for treatment, fly ash treatment device 40 for detoxifying fly ash separated from the molten exhaust gas, and basicity for adjusting the basicity of slag formed in the gasification melting furnace 20 And an adjustment device 60. Note that the type of waste to be processed in the waste processing system is not particularly limited. Examples of the waste include various wastes such as municipal waste, sewage sludge, and PCB contaminants.

  The waste supply unit 10 includes a waste pit 11, a waste transport device 12, and a dust supply device 13. The garbage pit 11 receives the garbage to be treated from outside the waste treatment system and temporarily stores it. The waste transport device 12 includes a waste crane 14, which picks up the waste in the waste pit 11 and transports it to the dust supply device 13. The dust supply device 13 includes a dust input hopper 15, and the dust input hopper 15 receives the dust input from the dust transport device 12. The dust supply device 13 has a built-in screw conveyor 16 for conveying dust, and supplies the dust charged in the dust charging hopper 15 to the gasification melting furnace 20.

  The gasification melting furnace 20 includes a gasification furnace 21 and a melting furnace 22. The gasification furnace 21 pyrolyzes the dust supplied from the dust supply device 13, thereby generating pyrolysis gas. As the gasification furnace 21, a known gasification furnace can be used, and examples thereof include a fluidized bed furnace and a kiln furnace. The melting furnace 22 burns combustible components in the pyrolysis gas at a high temperature and melts ash in the gas to generate slag. The slag adheres to the inside of the melting furnace 22, for example, the furnace wall of the melting furnace 22. A slag discharge port 23 is provided at the bottom of the melting furnace 22. The slag discharge port 23 is for discharging slag that adheres to the furnace wall and flows down to the outside of the furnace. Further, in this melting furnace 22, auxiliary fuel may be burned by a burner (not shown) as necessary for adjusting the temperature in the furnace.

  As shown in FIG. 2, the exhaust gas treatment unit 30 includes a waste heat boiler 31, a gas temperature reducing tower 32, a dust collector 34, an induction blower 35, and a chimney 36. FIG. 2 is a schematic diagram showing the configuration of the exhaust gas treatment unit 30. As shown in FIG. The waste heat boiler 31 is for recovering heat from the high-temperature molten exhaust gas discharged from the melting furnace 23. Specifically, for example, steam is generated and discharged using the heat of the molten exhaust gas. The gas temperature reducing tower 32 includes a tower main body into which molten exhaust gas discharged from the waste heat boiler 31 is introduced, a spraying device for spraying cooling water into the tower main body, and a gas temperature at the outlet of the tower main body. And a controller for adjusting the cooling water supply flow rate by the spraying device so as to keep the outlet gas temperature detected by the temperature sensor constant. The waste heat boiler 31 and the gas temperature reducing tower 32 lower the temperature of the molten exhaust gas to a temperature suitable for use in the subsequent dust collector 34.

  The dust collector 34 includes a bag filter 37 that filters and separates fly ash in the molten exhaust gas discharged from the gas temperature reducing tower 32. Further, the dust collector 34 may include an exhaust gas treatment chemical supply unit 33. The exhaust gas treatment chemical supply unit 33 supplies an exhaust gas treatment chemical to the molten exhaust gas discharged from the gas temperature reducing tower 32, thereby causing acidic gas components such as hydrogen chloride (HCl) and sulfur oxide ( SOx) and the like are neutralized and removed. At that time, the pH of the fly ash may also change. The type of heavy metals eluted from the fly ash varies depending on the pH of the fly ash. For example, if the pH is relatively low at about 10.5, Cr is eluted, but Pb is hardly eluted. If the pH is as high as 12.5, Pb and Cr are also eluted. The exhaust gas from which fly ash has been removed by the dust collector 34 is discharged from the chimney 36 through the induction blower 35. In addition, as an exhaust gas treatment chemical | medical agent, if it is an exhaust gas treatment chemical | medical agent for neutralizing the acidic gas component in molten exhaust gas, it can use without limitation. Specifically, alkaline substances, such as slaked lime and baking soda, etc. are mentioned, for example.

  The fly ash treatment device 40 is a device for suppressing the elution of heavy metals from the fly ash separated and collected by the dust collector 34 and detoxifying the fly ash. A fly ash storage tank 42, a fly ash charging hopper 43, a kneading device 44, a heavy metal elution prevention chemical supply unit 45, and a heavy metal elution prevention chemical supply amount control unit 46.

  The fly ash transport device 41 transports the fly ash separated and collected by the dust collector 34 to the fly ash storage tank 42. The fly ash storage tank 42 receives the fly ash transported by the fly ash transport device 41, temporarily stores it, and then puts it into the fly ash charging hopper 43. The timing of charging may be every time a predetermined amount is stored, or may be after a predetermined time has elapsed. The fly ash charging hopper 43 receives the fly ash charged from the fly ash storage tank 42 and transports it to the kneading device 44. The kneading device 44 kneads the fly ash conveyed by the fly ash charging hopper 43 and the heavy metal elution prevention chemical supplied by the heavy metal elution prevention chemical supply unit 45.

The heavy metal elution preventing chemical supply unit 45 includes a heavy metal elution preventing chemical storage tank 47 and a pump 48. The heavy metal elution preventing chemical storage tank 47 stores a heavy metal elution preventing chemical for preventing elution of heavy metals from fly ash. As the heavy metal elution preventing agent, any known heavy metal elution preventing agent can be used as long as it can prevent elution of heavy metal from fly ash by kneading with fly ash. Can do. Specifically, examples of the heavy metal elution preventing agent for Cr (VI) used for preventing and detoxifying toxic Cr (VI) include sodium sulfite and ferrous sulfate. By using these heavy metal elution preventing agents for Cr (VI), Cr (VI) can be reduced to trivalent chromium (Cr (III)), and elution of Cr (VI) is prevented. Moreover, as a heavy metal elution prevention agent for Pb used when preventing the elution of Pb and detoxifying, for example, dithiocarbamates such as dipotassium = piperazine-1,4-dicarbodithioate (heavy metal treating agent TS-275) And phosphoric acid. By using these heavy metal elution preventing agents for Pb, the heavy metal elution preventing agent for Pb is chelated with Pb, insolubilized (immobilized), and elution of Pb is prevented. The heavy metal elution preventing agent for Pb immobilizes not only Pb but also Cu. The pump 48 supplies the heavy metal elution preventing chemical stored in the heavy metal elution preventing chemical storage tank 47 to the kneading device 44. The supply amount at that time depends on the control of the heavy metal elution preventing chemical supply amount control unit 46.

  The heavy metal elution prevention chemical supply amount control unit 46 includes a heavy metal content measurement unit 49, a pH measurement unit 50, a supply amount target value calculation unit 51, and a heavy metal elution prevention chemical supply amount adjustment unit 52, which will be described later. Thus, the supply amount of the heavy metal elution preventing chemical is controlled.

  The heavy metal content measuring unit 49 includes a fluorescent X-ray analyzer, takes out part of the fly ash stored in the fly ash storage tank 42, and uses the fluorescent X-ray analyzer to measure the heavy metal in the fly ash. Measure the content. At that time, the content of each heavy metal is measured. In addition, in the case of Cr, it is measured not as the content of Cr (VI) but as the content of Cr including other valences of Cr (hereinafter also referred to as “T-Cr”). Moreover, as a fluorescent X-ray analyzer, a well-known fluorescent X-ray analyzer can be used, and an energy dispersive fluorescent X-ray analyzer is preferably used. Specifically, for example, OURSTEX 160 manufactured by Hours Tech Co., Ltd. and the like can be mentioned. The pH measuring unit 50 takes out part of the fly ash stored in the fly ash storage tank 42 and measures the pH of the eluate obtained by performing an elution process. A known pH measuring device can be used as the pH measuring device used at that time. Hereinafter, description will be given focusing on the case of Cr as the heavy metal.

  The supply amount target value calculation unit 51 can prevent elution of Cr (VI) from the T-Cr content output from the heavy metal content measurement unit 49 and the pH output from the pH measurement unit 50. The supply amount of the heavy metal elution preventing chemical for Cr (VI) is calculated as a target value. The calculation of the target value includes a step of calculating a ratio of the Cr (VI) elution amount to the T-Cr content at the measured pH, and a step of calculating an expected value of the Cr (VI) elution amount from the fly ash. And the step of calculating a target value. The supply amount of the heavy metal elution preventing agent capable of preventing elution of heavy metals such as Cr (VI) is preferably a minimum amount at which elution of heavy metals is a predetermined value, for example, a regulation value or less.

  The step of calculating the ratio of the Cr (VI) elution amount to the T-Cr content at the measured pH can be calculated from the pH output from the pH measuring unit 50. This indicates that there is a correlation between the pH of the eluate and the Cr (VI) elution amount with respect to the T-Cr content, and this correlation can be obtained in advance by actual measurement. Specifically, it is possible to estimate by measuring the pH of the eluate, the T-Cr content, and the Cr (VI) elution amount with various analyzers, respectively. It is possible to approximate to a linear expression (linear expression). That is, based on the correlation between the pH of the eluate prepared in advance and the Cr (VI) elution amount with respect to the T-Cr content, the Cr (VI with respect to the T-Cr content at the pH measured by the pH measurement unit 50). ) The ratio of elution amount can be calculated.

  Next, the step of calculating an expected value of the Cr (VI) elution amount from the fly ash includes the T-Cr content in the ratio of the Cr (VI) elution amount to the T-Cr content calculated in the step. It can be calculated by multiplying.

  Finally, the step of calculating the target value can be calculated from the predicted value. Specifically, there is a correlation between the amount of Cr (VI) elution and the amount of Cr (VI) heavy metal elution preventing agent that can prevent the dissolution of Cr (VI), and this correlation is measured in advance. It is possible to obtain by More specifically, the elution amount of Cr (VI) is measured with an analyzer, and in each elution amount, the elution amount of Cr (VI) becomes a predetermined value, for example, a regulation value or less, preventing elution of heavy metals for Cr (VI) It can be estimated by measuring the supply of the drug. Since the correlation follows a chemical equivalent, it can be approximated to a linear expression (linear expression), for example.

  As described above, the supply amount target value calculation unit 51 stores the correlation, and outputs the relationship, the T-Cr content output from the heavy metal content measurement unit 49, and the pH measurement unit 50. The supply amount of the heavy metal elution preventing agent for Cr (VI) capable of preventing the elution of Cr (VI) is calculated as a target value on the basis of the pH value.

  The heavy metal elution prevention chemical supply amount adjustment unit 52 outputs a control signal to the pump 48 so that the supply amount of the heavy metal elution prevention chemical for Cr (VI) becomes the target value, and drives the pump 48. Adjust time and drive speed.

  The supply amount target value calculation unit 51 and the heavy metal elution prevention chemical supply amount adjustment unit 52 are configured by a microcomputer or the like.

  The basicity adjusting device 60 is a device for adjusting the basicity of the slag discharged from the slag discharge port 23 of the melting furnace 22. The basicity adjusting device 60 includes a basicity adjusting agent supply device 61, a slag basicity measuring unit 62, and a basicity adjusting agent adjusting unit 63.

The basicity adjusting agent supply device 60 is a device for supplying a basicity adjusting agent into the garbage put into the gasification furnace 21, and is a screw conveyor 64 that is a conveying means for supplying the basicity adjusting agent, And a motor 65 for rotating the screw conveyor 64. As the basicity adjusting agent, a known basicity adjusting agent can be used. When the basicity of the discharged slag is high, specifically, for example, silica sand containing SiO ₂ as a main component in order to lower the basicity of the slag.

The slag basicity measuring unit 62 includes a fluorescent X-ray analyzer in the fly ash treatment apparatus 40. And each content of calcium (Ca) and silicon (Si) in the slag is measured by the fluorescent X-ray analyzer. The contents of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) are calculated from the respective contents of Ca and Si. Specifically, for example, in the case of CaO, a value obtained by multiplying the measured value of the Ca content by (40 + 16) /40=1.4 is the CaO content. For example, in the case of SiO ₂ , the value obtained by multiplying the measured value of the Si content by (28 + 16 × 2) / 28 = 15/7 is the SiO ₂ content. Then, the basicity (CaO / SiO ₂ ) is calculated from the ratio of the calculation results. By doing so, since the fluorescent X-ray analyzer here and the fluorescent X-ray analyzer in the fly ash processing apparatus 40 are the same, an initial investment amount can be reduced and it is preferable.

  The basicity adjusting agent adjusting unit 63 adjusts the supply amount of the basicity adjusting agent for the basicity calculated by the slag basicity measuring unit 62 to approach a preset target value, for example, 0.8. decide. Then, a control signal is output to the motor 65 of the basicity adjusting agent supply device 60 to control the driving speed so that the determined supply amount is obtained. The relationship between the measurement value of the basicity and the actual supply amount of the basicity adjusting agent can be prepared in advance theoretically or in simulation. The basicity adjusting agent adjusting unit 63 may be configured by a microcomputer or the like, and may be configured by the same microcomputer as the supply amount target value calculating unit 51 and the heavy metal elution preventing chemical supply amount adjusting unit 52. Good.

  As described above, the waste treatment system according to the present embodiment can appropriately and quickly estimate the supply amount of the heavy metal elution preventing agent that reliably prevents the elution of Cr, which is heavy metal from the fly ash, The fly ash can be easily detoxified without being supplied to the battery.

  In addition, the waste treatment system may not include the basicity adjusting device 60, but by using the fluorescent X-ray analyzer in the fly ash treatment device 40 by providing the basicity adjusting device 60. In addition, it is possible not only to quickly estimate an appropriate supply amount of the heavy metal elution preventing agent supplied to the fly ash, but also to quickly estimate an appropriate supply amount of the basicity adjusting agent to be supplied to the slag.

Further, the waste treatment system is not limited to the configuration of the exhaust gas treatment unit 30, and may be configured as shown in FIG. 3, for example. FIG. 3 is a schematic view showing another configuration of the exhaust gas treatment unit 30. The dust collector 34 includes an activated carbon supply unit 81, a first bag filter 38, an exhaust gas treatment chemical supply unit 33, and a second bag filter 39. The first bag filter 38 has the same configuration as the bag filter 37, and collects the first fly ash in the molten exhaust gas discharged from the gas temperature reducing tower 32 by filtration separation. The second bag filter 39 is provided in the subsequent stage of the first bag filter 38, and filters and separates the second fly ash remaining in the gas that has passed through the first bag filter 38. The activated carbon supply unit 81 supplies activated carbon to the molten exhaust gas discharged from the gas temperature reducing tower 32. And, by supplying the exhaust gas treatment chemical to the gas that has passed through the first bag filter 38 by the exhaust gas treatment chemical supply section 33 provided between the first bag filter 38 and the second bag filter 39. The acidic gas components in the molten exhaust gas, for example, hydrogen chloride (HCl), sulfur oxide (SOx), etc. are neutralized and removed. At that time, the pH of the fly ash also changes. The type of heavy metals eluted from the fly ash varies depending on the pH of the fly ash. By doing so, the second fly ash collected by the second bag filter 39 is more likely to elute Pb than the first fly ash collected by the first bag filter 38.

  The first fly ash from which Pb is less likely to be eluted from the second fly ash is subjected to a detoxification process by the first fly ash treatment device 71. At this time, Pb is not easily eluted from the first fly ash, but the first fly ash treatment device 71 may be subjected to a detoxification treatment that suppresses not only Cr (VI) but also Pb elution. The second fly ash is detoxified by the second fly ash treatment device 72. As the first fly ash treatment device 71 and the second fly ash treatment device 72, the fly ash treatment device 40 is different except that the heavy metal elution prevention chemical supply amount control unit is different from the heavy metal elution prevention chemical supply amount control unit 46. The same can be used. The heavy metal elution prevention drug supply amount control unit here includes a heavy metal content measurement unit, a supply amount target value calculation unit, and a heavy metal elution prevention drug supply amount adjustment unit. Control the supply amount.

  The heavy metal content measurement unit is the same as the heavy metal content measurement unit 49 of the heavy metal content measurement unit 46, and is in the first fly ash and the second fly ash (hereinafter also referred to as each fly ash). Measure heavy metal content. In addition, since the process of Cr (VI) from each fly ash is the same as that of said case here, Pb in each fly ash is demonstrated. The supply amount target value calculation unit is a Pb heavy metal elution preventing agent capable of preventing harmful Pb elution regardless of the Cu content from the Pb and Cu contents output from the heavy metal content measurement unit. The supply amount is calculated as a target value. The calculation of the target value is achieved by calculating an expected value of the elution amount of Pb and Cu from each fly ash and calculating a target value.

  The step of calculating the predicted value of the elution amount of Pb and Cu from each fly ash can be calculated from the content of Pb and Cu output from the heavy metal content measurement unit. This indicates that there is a correlation between the content of Pb and Cu and the elution amount of Pb and Cu, and this correlation can be obtained in advance by actual measurement. Specifically, it can be estimated by measuring the contents of Pb and Cu and the amounts of elution of Pb and Cu with various analyzers, respectively. It is possible to approximate That is, the predicted value of the elution amount of Pb and Cu from each fly ash can be calculated based on the correlation between the Pb and Cu content prepared in advance and the elution amount of Pb and Cu.

  Next, the step of calculating the target value can be calculated from the predicted value. This indicates that there is a correlation between the elution amount of Pb and Cu and the supply amount of the heavy metal elution preventing agent for Pb capable of preventing the elution of Pb, and this correlation can be obtained in advance by actual measurement. . Specifically, the elution amounts of Pb and Cu are measured by an analyzer, and the supply amount of the heavy metal elution preventing agent for Pb for which the Pb elution amount becomes a predetermined value, for example, a regulation value or less, is measured in each elution amount. Therefore, it is possible to estimate. Since the correlation follows a chemical equivalent, it can be approximated to a linear expression (linear expression), for example.

  As described above, the supply amount target value calculation unit stores the correlation, and relates to the Cu content based on the relationship and the Pb and Cu contents output from the heavy metal content measurement unit. First, the supply amount of the Pb heavy metal elution preventing chemical capable of preventing harmful Pb elution is calculated as a target value.

  The heavy metal elution prevention chemical supply amount adjusting unit outputs a control signal to the pump 48 so that the supply amount of the heavy metal elution prevention chemical for Pb becomes the target value, and the driving time and driving speed of the pump 48 Adjust etc.

  Here, the supply amount target value calculation unit and the heavy metal elution prevention chemical supply amount adjustment unit are configured by a microcomputer or the like, and the supply amount target value calculation unit 51 and the heavy metal elution prevention chemical supply amount adjustment unit 52 The basicity adjusting agent adjusting unit 63 may be composed of the same microcomputer or the like.

  Hereinafter, actual measurement values and the like in the case where the waste treatment system is used will be described.

  First, Cr, which is a heavy metal, will be described.

  FIG. 4 shows the relationship between the T-Cr content in fly ash and the elution amount of Cr (VI) from untreated fly ash in three waste treatment systems (facility A, facility B, and facility C). It is a graph. As shown in FIG. 4, it can be seen that there is no correlation between the T-Cr content in the fly ash and the Cr (VI) elution amount from the fly ash. From this, it is not possible to estimate the amount of Cr (VI) elution only by measuring the T-Cr content in the fly ash. Indicates that the operation cannot be performed.

However, it can be seen that there is a proportional relationship (linear function) between the content of Cr (VI) and the amount of elution of Cr (VI). The elution amount of VI) will also be known. Further, even when the Cr (VI) content cannot be measured, the Cr (VI) content and the Cr (VI) elution amount can be estimated by multiplying the measurable T-Cr content by a predetermined coefficient. It can be said. Here, the correlation between the pH of the eluate and the ratio of the Cr (VI) elution amount to the T-Cr content for calculating an appropriate supply amount of the heavy metal elution preventing agent for Cr (VI) will be described.

  FIG. 5 is a graph showing the relationship between the pH of the eluate and the ratio of the Cr (VI) elution amount to the T-Cr content in the three waste treatment systems (facility A, facility B, and facility C). As shown in FIG. 5, it can be seen that there is a correlation between the pH of the eluate and the ratio of the Cr (VI) elution amount to the T-Cr content for each facility.

  FIG. 6 is a graph showing the relationship between the Cr (VI) elution amount estimated from the T-Cr content and the pH of the eluate and the Cr (VI) elution amount from untreated fly ash. The Cr (VI) elution amount estimated from the T-Cr content here and the pH of the eluate is a correlation between the pH of the eluate in each facility and the ratio of the Cr (VI) elution amount to the T-Cr content. Based on the relationship, it is a value obtained by multiplying the measured value of the T-Cr content by the ratio of the Cr (VI) elution amount to the T-Cr content at the measured pH. As shown in FIG. 6, the ratio of Cr (VI) elution amount to T-Cr content at the measured pH was multiplied by the measured value of T-Cr content and the actual Cr (VI from untreated fly ash ) It can be seen that there is a correlation with the elution amount. From this, the amount of Cr (VI) elution can be estimated by measuring the pH of the eluate and the Cr content in the fly ash. Indicates that the supply amount can be calculated.

  Next, Pb, which is a heavy metal, which is provided with an elution reference value at the time of landfill disposal will be described.

  FIG. 7 is a graph showing the annual transition of the Pb content in the fly ash and the Pb elution amount from the fly ash in a certain waste treatment system. FIG. 7 clearly shows that the Pb content in the fly ash and the Pb elution from the fly ash change close to each other.

  FIG. 8 is a graph showing the relationship between the Pb content in the fly ash and the Pb elution amount from the untreated fly ash in the two waste treatment systems (facility D and facility E). FIG. 9 is a graph showing the relationship between the Cu content in the fly ash and the Cu elution amount from the untreated fly ash in the two waste treatment systems (facility D and facility E). As shown in FIGS. 8 and 9, it can be seen that there is a correlation between the contents of Pb and Cu in the fly ash and the elution amounts of Pb and Cu from the untreated fly ash. From this, the elution amounts of Pb and Cu can be estimated by measuring the contents of Pb and Cu in the fly ash. Therefore, it is shown that an appropriate supply amount of the heavy metal elution preventing agent for Pb can be calculated. This can also be seen from FIG.

  FIG. 10 shows the estimated required amount of the heavy metal elution preventing agent calculated from the estimated elution amounts of Pb and Cu and the actual required amount of the heavy metal elution preventing agent in the two waste treatment systems (facility D and facility E). It is the graph which showed the relationship. The estimated necessary amount of the heavy metal elution preventing agent is an estimated necessary amount of the heavy metal elution preventing agent calculated from the estimated elution amount of Pb and Cu estimated from the contents of Pb and Cu. In addition, the actual required amount of the heavy metal elution preventing agent is the amount of the heavy metal elution preventing agent that is actually required for the elution amount of Pb from the fly ash to be a predetermined amount, for example, a regulated value or less. FIG. 10 shows that an appropriate supply amount of the heavy metal elution preventing agent for Pb can be calculated from the estimated elution amounts of Pb and Cu.

  Finally, the basicity of slag will be described.

  FIG. 11 is a graph showing the relationship between slag basicity and slag melting point. FIG. 12 is a graph showing the relationship between the basicity of slag and the slag melting point. The slag melting point is the temperature at which slag begins to flow in a melting furnace or the like. As can be seen from FIGS. 11 and 12, it is preferable that the basicity of the slag is around 0.8, for example, about 0.5 to 1.1, because the slag flows at 1250 ° C. or less.

  FIG. 13 is a graph showing the results of measuring the basicity of slag with an atomic absorption device and a fluorescent X-ray analyzer. As can be seen from FIG. 13, even if the basicity of slag is measured using a fluorescent X-ray analyzer, the same result as that obtained by measuring with an atomic absorption device can be obtained. From this, even if the fluorescent X-ray analyzer used for quantification of the heavy metal elution preventing agent is used as it is, the content of heavy metal in the fly ash can be measured as in the case of the atomic absorption device. Therefore, the basicity of the slag obtained by measurement with the fluorescent X-ray analyzer is a reference for adjusting the supply amount of the basicity adjusting agent so that the basicity becomes a predetermined basicity, for example, around 0.8. .

It is the schematic which shows the whole structure of the waste disposal system which concerns on embodiment of this invention. FIG. 2 is a schematic view showing a configuration of the exhaust gas treatment unit 30. FIG. 4 is a schematic diagram illustrating another configuration of the exhaust gas treatment unit 30. It is a graph which shows the relationship between T-Cr content in fly ash and the elution amount of Cr (VI) from untreated fly ash in three waste disposal systems (facility A, facility B, and facility C). It is a graph which shows the relationship between the pH of an eluate, and the ratio of Cr (VI) elution amount with respect to T-Cr content in three waste disposal systems (facility A, facility B, and facility C). It is a graph which shows the relationship between Cr (VI) elution amount estimated from T-Cr content and pH of an eluate, and Cr (VI) elution amount from untreated fly ash. It is the graph which showed each annual transition of Pb content in the fly ash in a certain waste disposal system, and the Pb elution amount from fly ash. It is a graph which shows the relationship between Pb content in fly ash and the amount of Pb elution from untreated fly ash in two waste disposal systems (facility D and facility E). It is a graph which shows the relationship between Cu content in fly ash and the amount of Cu elution from untreated fly ash in two waste disposal systems (facility D and facility E). In the two waste treatment systems (facility D and facility E), the relationship between the estimated required amount of heavy metal elution prevention chemical calculated from the estimated elution amount of Pb and Cu and the actual required amount of heavy metal elution prevention chemical was shown. It is a graph. It is a graph which shows the relationship between the basicity of slag, and a slag melting point. It is a graph which shows the relationship between the basicity of slag and a slag melting point. It is a graph which shows the result of having measured the basicity of slag with the atomic absorption device and the fluorescent X ray analyzer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Garbage supply part 11 Garbage pit 12 Garbage transport apparatus 13 Dust supply apparatus 14 Garbage crane 15 Garbage throw-in hopper 16,64 Screw conveyor 20 Gasification melting furnace 21 Gasification furnace 22 Melting furnace 23 Slag discharge port 30 Exhaust gas treatment part 31 Waste heat Boiler 32 Gas decooling tower 33 Conditioning agent supply unit 34 Dust collector 35 Induction fan 36 Chimney 37 Bag filter 38 First bug filter 39 Second bag filter 40 Fly ash treatment device 41 Fly ash carry-out device 42 Fly ash storage tank 43 Fly Ash injection hopper 44 Kneading device 45 Heavy metal elution prevention chemical supply unit 46 Heavy metal elution prevention chemical supply amount control unit 47 Heavy metal elution prevention chemical reservoir 48 Pump 49 Heavy metal content measurement unit 50 pH measurement unit 51 Supply amount target value calculation unit 52 Heavy metal Elution prevention chemical supply amount adjustment unit 60 Basicity adjustment device 61 Basicity Seizai feeder 62 slag basicity measuring unit 63 basicity adjusting agents adjusting unit 65 motor 71 first fly ash treatment apparatus 72 the second fly ash treatment apparatus

Claims (6)

It is provided in a waste treatment system equipped with a gasification melting furnace that pyrolyzes the input waste and melts ash in the pyrolysis gas generated by the thermal decomposition to slag, and is discharged from the gasification melting furnace. A fly ash treatment device for suppressing elution of heavy metals from fly ash contained in molten exhaust gas collected by dust collecting means,
Kneading means for supplying and kneading a heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash;
Cr content measuring means for measuring the total chromium (Cr) content in the fly ash;
PH measuring means for measuring the pH of the eluate from the fly ash,
Based on the correlation between the pH of the eluate prepared in advance and the ratio of the Cr (VI) elution amount to the Cr content, the ratio of the Cr (VI) elution amount to the Cr content at the measured pH is calculated and calculated. By multiplying the measured ratio of Cr content by the measured value of Cr content, the expected value of Cr (VI) elution from the fly ash can be calculated, and elution of Cr (VI) can be prevented based on the expected value Calculation means for calculating the supply amount of the heavy metal elution preventing chemical for Cr (VI) as a target value;
A supply amount adjusting means for adjusting the supply amount of the heavy metal dissolution preventing agent for Cr (VI) so as to be the target value;
The fly ash treatment apparatus, wherein the Cr content measuring means is a fluorescent X-ray analyzer. It is provided in a waste treatment system equipped with a gasification melting furnace that pyrolyzes the input waste and melts ash in the pyrolysis gas generated by the thermal decomposition to slag, and is discharged from the gasification melting furnace. A fly ash treatment device for suppressing elution of heavy metals from fly ash contained in molten exhaust gas collected by dust collecting means,
Heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash, Heavy metal for Pb for preventing elution of lead (Pb) in the fly ash A kneading means for supplying and kneading the dissolution agent to the fly ash,
Heavy metal content measuring means for measuring the total chromium (Cr), copper (Cu) and Pb content in the fly ash;
PH measuring means for measuring the pH of the eluate from the fly ash,
Based on the correlation between the pH of the eluate prepared in advance and the ratio of the Cr (VI) elution amount to the Cr content, the ratio of the Cr (VI) elution amount to the Cr content at the measured pH is calculated and calculated. By multiplying the measured ratio of Cr content by the measured value of Cr content, the expected value of Cr (VI) elution amount from the fly ash is calculated, and Cr (VI) is calculated based on the expected value of Cr (VI) elution amount. First calculation means for calculating the supply amount of the heavy metal elution preventing agent for Cr (VI) capable of preventing elution)) as a first target value;
First supply amount adjusting means for adjusting the supply amount of the Cr (VI) heavy metal elution preventing chemical to be the first target value;
Based on the correlation between the Pb and Cu contents prepared in advance and the Pb and Cu elution quantities, the predicted values of the Pb and Cu elution quantities from the fly ash are calculated from the measured values of the Pb and Cu contents. And the supply amount of the heavy metal elution preventing agent for Pb capable of preventing the elution of Pb regardless of the Cu content is calculated as the second target value based on the predicted values of the elution amounts of Pb and Cu. A second computing means;
A second supply amount adjusting means for adjusting a supply amount of the heavy metal elution preventing agent for Pb so as to be the second target value;
The fly ash treatment apparatus, wherein the heavy metal content measuring means is a fluorescent X-ray analyzer. A waste treatment system comprising a gasification melting furnace for pyrolyzing waste to be input and melting ash in pyrolysis gas generated by the thermal decomposition to slag,
A basicity adjusting agent for adjusting the basicity (CaO / SiO ₂ ) of the slag discharged from the slag discharge port is supplied to a position upstream of the slag discharge port for discharging the slag out of the furnace. Basicity adjusting agent supply means;
Basicity measuring means for measuring the basicity of the slag;
Basicity adjusting agent supply amount adjusting means for adjusting the supply amount of the basicity adjusting agent so that the measured basicity becomes a target value of preset basicity;
The fly ash treatment apparatus according to claim 1 or 2,
The basicity measuring means includes the fluorescent X-ray analyzer in the fly ash treatment apparatus, and the fluorescent X-ray analyzer determines the contents of calcium (Ca) and silicon (Si) in the slag, respectively. It has means for measuring, calculating the contents of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) from the respective contents of Ca and Si, and calculating the basicity from the calculation results. And waste treatment system. When operating a waste treatment system equipped with a gasification melting furnace that pyrolyzes the input waste and melts ash in the pyrolysis gas generated by the thermal decomposition and slags it, it is discharged from the gasification melting furnace a fly ash treatment method for inhibiting the elution of heavy metals from the collected fly ash in which dust collecting unit included in the molten exhaust gas,
A kneading step of supplying and kneading a heavy metal elution preventing agent for Cr (VI) to prevent elution of hexavalent chromium (Cr (VI)) in the fly ash;
A Cr content measurement step for measuring the total chromium (Cr) content in the fly ash;
A pH measurement step for measuring the pH of the eluate from the fly ash;
Based on the correlation between the pH of the eluate prepared in advance and the ratio of the Cr (VI) elution amount to the Cr content, the ratio of the Cr (VI) elution amount to the Cr content at the measured pH is calculated and calculated. By multiplying the measured ratio of Cr content by the measured value of Cr content, the expected value of Cr (VI) elution from the fly ash can be calculated, and elution of Cr (VI) can be prevented based on the expected value A calculation step of calculating the supply amount of the heavy metal elution preventing agent for Cr (VI) as a target value;
A supply amount adjusting step of adjusting the supply amount of the heavy metal elution preventing chemical for Cr (VI) so as to be the target value;
The fly ash treatment method, wherein the Cr content measurement step uses a fluorescent X-ray analyzer. When operating a waste treatment system equipped with a gasification melting furnace that pyrolyzes the input waste and melts ash in the pyrolysis gas generated by the thermal decomposition and slags it, it is discharged from the gasification melting furnace a fly ash treatment method for inhibiting the elution of heavy metals from the collected fly ash in which dust collecting unit included in the molten exhaust gas,
Heavy metal elution preventing agent for Cr (VI) for preventing elution of hexavalent chromium (Cr (VI)) in the fly ash, Heavy metal for Pb for preventing elution of lead (Pb) in the fly ash A kneading step of supplying and kneading the dissolution agent to the fly ash;
A heavy metal content measuring step for measuring each content of total chromium (Cr), copper (Cu) and Pb in the fly ash;
A pH measurement step for measuring the pH of the eluate from the fly ash;
Based on the correlation between the pH of the eluate prepared in advance and the ratio of the Cr (VI) elution amount to the Cr content, the ratio of the Cr (VI) elution amount to the Cr content at the measured pH is calculated and calculated. By multiplying the measured ratio of Cr content by the measured value of Cr content, the expected value of Cr (VI) elution amount from the fly ash is calculated, and Cr (VI) is calculated based on the expected value of Cr (VI) elution amount. A first calculation step of calculating, as a first target value, the supply amount of the Cr (VI) heavy metal elution preventing agent capable of preventing elution);
A first supply amount adjusting step of adjusting the supply amount of the Cr (VI) heavy metal elution preventing chemical to be the first target value;
Based on the correlation between the Pb and Cu contents prepared in advance and the Pb and Cu elution quantities, the predicted values of the Pb and Cu elution quantities from the fly ash are calculated from the measured values of the Pb and Cu contents. And the supply amount of the heavy metal elution preventing agent for Pb capable of preventing the elution of Pb regardless of the Cu content is calculated as the second target value based on the predicted values of the elution amounts of Pb and Cu. A second calculation step;
A second supply amount adjustment step of adjusting the supply amount of the heavy metal elution preventing agent for Pb to be the second target value,
The fly ash treatment method, wherein the heavy metal content measurement step uses a fluorescent X-ray analyzer. It is a method for operating a waste treatment system comprising a gasification melting furnace for pyrolyzing waste to be charged and melting ash in pyrolysis gas generated by the pyrolysis to slag.
A basicity adjusting agent for adjusting the basicity (CaO / SiO ₂ ) of the slag discharged from the slag discharge port is supplied to a position upstream of the slag discharge port for discharging the slag out of the furnace. A basicity adjusting agent supplying step;
A basicity measuring step for measuring the basicity of the slag;
A basicity adjuster supply amount adjustment step of adjusting the supply amount of the basicity adjustor so that the measured basicity becomes a target value of a preset basicity;
A fly ash treatment process for suppressing elution of heavy metals from the fly ash by the fly ash treatment method according to claim 4 or claim 5,
The basicity measurement step measures the contents of calcium (Ca) and silicon (Si) in the slag using the fluorescent X-ray analyzer in the fly ash treatment step, and the Ca and Si. And calculating the content of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) from each content, and calculating the basicity from the calculation result. how to drive.

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