JP2004132689A - Heat recovery and recycling method and system for waste activated carbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat recovery and recycling method and system for waste activated carbon disposed from a gas treatment and/or water treatment facility. <P>SOLUTION: The system is composed so that the waste activated carbon and coal disposed from the gas treatment and/or water treatment facility is stored in an existing coal yard 2 adjacent to a combustion facility 6. In the system, water is sprinkled on the waste activated carbon and coal via a sprinkling means 8 during storage in the coal yard 2 to remove chemicals and adsorbed components adsorbed by the waste activated carbon. The waste activated carbon and coal are pulverized by a pulverizing means 4, and a pulverized coal mixture of the waste activated carbon and the coal is burned by the combustion facility 6. In this case, low grade coal can be used as the coal. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method and an apparatus for treating waste activated carbon and a method and a system for heat recovery and reuse, and more particularly to a method and a system for heat recovery and reuse of waste activated carbon discarded from a gas treatment facility or a water treatment facility.

Activated carbon, which exhibits an excellent adsorption effect, is widely used in various facilities such as exhaust gas treatment, wastewater treatment, sewage treatment, and water purification treatment.
For example, in an exhaust gas treatment facility such as a dioxin removal facility for a combustion exhaust gas, an activated carbon adsorption tower filled with activated carbon is used, and the combustion exhaust gas is passed through the activated carbon adsorption tower, and the dioxin and the like contained in the combustion exhaust gas are used. Harmful substances are adsorbed on activated carbon. Further, in the organic solvent removal equipment, an exhaust gas from a process using an organic solvent, such as a printing plant, is passed through an activated carbon adsorption tower filled with activated carbon to adsorb an organic solvent such as toluene onto the activated carbon.

Further, in the water purification treatment equipment, after the raw tap water is subjected to coagulation and sedimentation treatment and / or sand filtration treatment, various mold odors, trihalomethane which is a carcinogenic substance, and humic substances which are precursors of trihalomethane are used. In the step of removing organic substances by adsorption, advanced treatment is performed using granular activated carbon.

Activated carbon used in these gas treatment facilities and water treatment facilities is often impregnated with chemicals for adsorbing substances to be removed, and waste activated carbon contains not only substances to be removed but also impregnated chemicals. ing. For example, phosphoric acid for removing ammonia, an acid such as sulfuric acid, an alkaline agent such as caustic soda for removing hydrogen sulfide, an agent impregnated with halogen such as bromine for removing methyl sulfide, ammonia, hydrogen sulfide, methyl mercaptan, Various chemical substances are included, such as a substance to be removed such as methyl sulfide and methyl disulfide, and a substance obtained by modifying a substance to be removed adsorbed on activated carbon by oxidation or the like.

In addition, activated carbon used as an adsorbent in gas treatment equipment and water treatment equipment cannot be used permanently, and it is necessary to replace it with new activated carbon at least before breakthrough, and preferably before adsorption capacity decreases. is there. For example, in the advanced treatment in a water treatment facility, the concentration of the substance to be removed is very low at 1 mg / L or less. Therefore, the exchange frequency of the activated carbon is as small as about once every 5 to 7 years. Since activated carbon is used, the amount of waste activated carbon discarded at the time of replacement amounts to several thousand tons. In addition, advanced treatment facilities are often installed in water treatment plants that use surface water or underground water of highly polluted rivers in urban areas and suburbs near large cities as raw water, and the treatment capacity of such urban water treatment plants is one. Hundreds of thousands to millions of tons per day, and the amount of waste activated carbon discarded during replacement is very large. In the days when activated carbon was once expensive, the recycling of old activated carbon was the mainstream for the reuse of these large amounts of waste activated carbon, but under the current situation where activated carbon has become inexpensive, activated carbon recycling is economical. It is no longer a reuse method.

For this reason, various methods for reusing waste activated carbon other than recycling have been proposed.
For example, in the gas treatment of combustion exhaust gas, dioxin in the exhaust gas is passed through an activated carbon adsorption tower, and in a method of removing dioxin, granular activated carbon containing dioxin is turned into powdered activated carbon with a pulverizer and sprayed in front of a dust collector, A method of utilizing waste activated carbon for adsorbing and removing dioxin from exhaust gas has been proposed (JP-A-2000-45647).

In addition, a method of using waste activated carbon, in which waste activated carbon having a volatile content of 10 to 20% by weight and a water content of 0.1 or more, which is discarded from the water purification process, is charged into a coke oven together with coke raw material coal, has been proposed. (JP-A-2002-38161).

Furthermore, waste activated carbon is used as a raw material for sintering in steel mills, silica, calcium oxide, and alumina oxide in waste activated carbon are used for blast furnace slag, and carbon in waste activated carbon and hydrocarbons in adsorbent are used as fuel and reducing agent, A method of using waste activated carbon used as a substitute for coke has been proposed (JP-A-2002-88416).

However, there is a problem that the amount of waste activated carbon discharged from the water treatment equipment reaches several thousand tons / time, and it is difficult to secure a space for temporarily storing the waste activated carbon for reuse.
In addition, the water content of waste activated carbon discharged from water treatment equipment such as water purification treatment is as high as about 50%, and it is necessary to dry it in advance in order to burn it in a coke oven and reuse it as a raw material for sintering. There is a problem that the process and the equipment become complicated, and the capital investment becomes excessive.

Furthermore, there is also a problem that it becomes difficult to transport waste activated carbon to a place where it is reused if it is pulverized.
Waste activated carbon discharged from gas treatment equipment and water treatment equipment contains a large amount of harmful chemical substances. There is a problem that secondary pollution occurs such as corrosion and air pollution caused by sulfur oxides contained in exhaust gas after reuse.

On the other hand, low-grade coal, which is used as coal, has a high sulfur content and, if burned untreated, has an adverse effect on living organisms and produces large amounts of dust and SOx, which cause acid rain and global warming. appear. In addition, since the ash content is large and a large amount of fly ash is produced after combustion, the cost of treating industrial waste increases. Furthermore, since low-grade coal alone has a small heat of combustion, a large amount of low-grade coal must be burned in order to obtain the required amount of heat, leading to the generation of a large amount of dust, SOx, fly ash, etc., and air pollution. Problems and industrial waste disposal problems are increasing.

JP 2002-45647 A JP 2002-38161 A JP 2002-88416 A

Accordingly, an object of the present invention is to provide a method and a system for reusing a large amount of waste activated carbon inexpensively, easily and without causing secondary pollution.
Specifically, it is an object of the present invention to provide a method and a system for reusing waste activated carbon, which can reduce a processing cost and simplify a processing step by eliminating a drying step.

It is another object of the present invention to provide a method and system for removing harmful substances adsorbed on waste activated carbon in advance and reusing the waste activated carbon without causing secondary pollution.
It is another object of the present invention to provide a method and system for securing a space for storing a large amount of waste activated carbon and easily reusing the waste activated carbon.

Still another object of the present invention is to provide a method and a system that can solve the difficulty of transporting the pulverized waste activated carbon and easily reuse the waste activated carbon.
It is a further object of the present invention to provide a method and a system for reusing waste activated carbon that solve the problem of generation of a large amount of dust and SOx associated with low-grade coal combustion.

Further, it is an object of the present invention to provide a method and a system for heat recovery and reuse of waste activated carbon, which can assist the amount of heat that tends to be insufficient in low-grade coal combustion.

According to the present invention, there is provided a method for heat recovery and reuse of waste activated carbon, characterized in that waste activated carbon is pulverized into coal, and a mixture of the pulverized waste activated carbon and coal is supplied to coal combustion means and burned. Is done.

廃 Waste activated carbon that can be reused in the present invention may be any used waste activated carbon, and is not particularly limited. However, in the case of waste activated carbon from a gas treatment facility and / or a water treatment facility which adsorbs the impregnated drug or harmful substance and is not desired to be reused for other uses, the heat recovery and reuse of the present invention The method is particularly effective. For example, waste of activated carbon used in an activated carbon adsorption tower in an exhaust gas treatment facility such as a dioxin removal facility for combustion exhaust gas, disposal of activated carbon used in an activated carbon adsorption device that adsorbs organic solvent from exhaust gas from an organic solvent use process And various organic substances, such as residual mold odor, carcinogenic trihalomethane, and humic substances that are precursors of trihalomethane after coagulation and sedimentation and / or sand filtration of raw water in wastewater treatment facilities Waste activated carbon such as activated carbon waste used in the step of adsorbing and removing CO2 and wastewater, activated carbon waste for removing COD and chromaticity, and activated carbon waste for deodorizing malodorous gas such as hydrogen sulfide can be preferably exemplified. These waste activated carbons contain chemicals impregnated with acids such as phosphoric acid and sulfuric acid for removing ammonia, alkaline agents such as caustic soda for removing hydrogen sulfide, halogens such as bromine for removing methyl sulfide, ammonia, sulfuric acid, and the like. Various chemical substances are often contained, such as hydrogen, methyl mercaptan, methyl sulfide, methyl disulfide, and other substances to be removed, and sulfur to which the substances to be removed adsorbed on activated carbon have been modified by oxidation or the like.

The shape of the waste activated carbon is not particularly limited, and may be various shapes such as a granular shape, a crushed shape, and a columnar shape.
In the present invention, as the coal mixed with the waste activated carbon, ordinary coal can be used without limitation. For example, high-grade coal such as bituminous coal and anthracite, lignite, sub-bituminous coal, and low-grade coal such as peat and lignite can be preferably exemplified. In particular, when using low-grade coal with a fixed carbon of 55% or less, such as lignite, mixing with waste activated carbon can compensate for the shortage of calories of low-grade coal and achieve combustion purposes such as power generation and steam generation. This is preferable because it is possible to reduce the amount of low-grade coal used to obtain the required calorific value and consequently to suppress the generation of dust and SOx.

燃 焼 The combustion means that can be used in the present invention is not particularly limited as long as it is a normal coal combustion facility. For example, commercial or private coal-fired power plants that generate electricity using coal as fuel, boilers such as private power plants in factories and industrial complexes, steam boilers that generate steam, furnaces such as cement manufacturing kilns, and industrial waste incinerators And general combustion equipment such as a pyrolysis furnace. In particular, coal-fired power generation equipment is preferable in view of the uniformity of fuel by co-firing with waste activated carbon, the use of existing combustion burners, and the amount of fuel used.

混合 The mixing ratio of the pulverized coal of the waste activated carbon and the coal to be burned in the present invention is not particularly limited, but it is preferable that the mixing ratio does not affect the desired fuel efficiency of the fuel equipment. For example, when mixing and burning in a fuel facility such as a commercial thermal power plant, it is preferable to mix in a range of waste activated carbon: coal = 1: 9 to 7: 3, and in a fuel facility such as a private power generation facility. In the case of mixing and burning, it is preferable to mix in a range of waste activated carbon: coal = 1: 9 to 9: 1. When high-grade coal is used as the coal, the sulfur content and ash content are lower than those of low-grade coal, so that the mixing ratio of waste activated carbon can be reduced as compared with the case of low-grade coal.

In the present invention, the mixing of the waste activated carbon and the coal may be performed before or after the pulverization of the waste activated carbon and the coal, and the order of the mixing and the pulverization is not particularly limited. Mixing can be performed in a usual manner. For example, after each of the waste activated carbon and coal is pulverized, both may be mixed and supplied to the combustion means. Alternatively, the waste activated carbon and the coal may be mixed, pulverized, and supplied to the combustion means.

に お い て In the present invention, in order to pulverize the waste activated carbon and the coal, an ordinary pulverizer can be used. For example, by driving a container containing a rod ball as a pulverizing medium, applying a centrifugal force to the pulverizing medium, between the media and between the medium and the container wall, applying an impact force, a shearing force, and a frictional force to the waste activated carbon. A ball mill for grinding, a tube mill, a roll mill for rotating a disc-shaped table or a cylindrical wall while pressing a roller against hydraulic pressure and centrifugal force can be preferably used. By utilizing frictional heat using a ball mill, roller mill, etc., the water contained in the waste activated carbon is removed by evaporation, so when reusing waste activated carbon with a high water content from water treatment equipment, etc. There is no need to provide a separate drying step.

粒径 In the present invention, the particle size of pulverized coal, which is a mixture of waste activated carbon and coal obtained by pulverization, is preferably in the range of several μm to 1 mm. If the particle size is smaller than several μm, the cost of pulverized coal production increases, and if the particle size exceeds 1 mm, wear and blockage of the combustion burner and the like are caused, which is not preferable.

In addition, in the present invention, before pulverizing the waste activated carbon, it is preferable to sprinkle water on the waste activated carbon to remove the components to be adsorbed and / or the impregnated chemicals adsorbed on the waste activated carbon. By spraying water, the components to be adsorbed and / or the impregnated chemicals are oxidized and decomposed into water-soluble and stable sulfates and nitrates by the action of microorganisms inside the pores of the waste activated carbon, and together with the water, Spilled out of the tank. In particular, in the case of waste activated carbon from a water treatment facility and / or a gas treatment facility used for the purpose of deodorization, ammonia is contained as a component to be adsorbed, and phosphorus is contained as an impregnated agent for removing ammonia. Since ammonia and phosphorus also serve as nutrients and enhance microbial activity, oxidative degradation of the adsorbed component and / or the impregnated drug by the microbe is promoted. In this way, harmful substances are biologically removed from the sprinkled waste activated carbon, so that secondary pollution due to an increase in sulfur oxides can be prevented. Sprinkling can also prevent spontaneous ignition and dust generation of waste activated carbon and coal during storage.

In the present invention, before pulverizing the waste activated carbon discarded from the gas treatment facility and / or the water treatment facility, it is preferable to store the waste activated carbon in a storage space close to the combustion facility. As this storage space, a coal storage yard, a coal yard, or the like, which is generally provided in a coal-fired power generation facility or the like and stores coal, can be used. Specifically, waste activated carbon can be easily stored by accumulating it on coal stored in a coal storage yard or a coal yard, and the waste activated carbon and coal may be mixed during storage. By storing waste activated carbon and coal together, it is possible to prevent spontaneous ignition of coal, and to reduce the amount of water spray and the frequency of water spray. This is because coal does not have pores that can hold moisture, but waste activated carbon has pores, so that sprinkled water can be retained in the pores of waste activated carbon. . The water retention of the pores is about 50% w / w per dry basis.

Further, according to the present invention, storage means for storing waste activated carbon and coal together, pulverizing means for pulverizing waste activated carbon and coal, and burning pulverized coal comprising pulverized waste activated carbon and coal And a combustion means for causing the waste activated carbon to recover and reuse heat.

Preferably, the storage means further comprises a watering means.
Preferably, the storage means is an existing coal storage space provided close to the combustion means.

Further, the present invention includes the following aspects.
1. Waste activated carbon discarded from a gas treatment facility and / or a water treatment facility is accumulated in a coal storage plant of a coal-fired power plant, and the accumulated waste activated carbon is pulverized together with fuel charcoal, and then supplied to a boiler. A method for treating waste activated carbon, comprising treating wastewater with heat recovery.
2. The waste activated carbon accumulated in the coal storage plant of the coal-fired power plant is pulverized after biologically decomposing and removing an adsorbed component and / or an impregnated drug that have been adsorbed by spraying water. A method for treating waste activated carbon as described in the above item.
3. A coal storage plant of a coal-fired power plant having a sprinkling means for accumulating waste activated carbon discarded from a gas treatment facility and / or a water treatment facility; a pulverizing device for pulverizing waste activated carbon and fuel coal in the coal storage facility; A waste activated carbon processing apparatus, comprising: a boiler for burning pulverized fuel.

ADVANTAGE OF THE INVENTION According to the recycling method and system of the waste activated carbon of this invention, the waste activated carbon discharged | emitted in large quantities can be reused cheaply and easily by heat recovery, without causing secondary pollution.
According to the method and system of the present invention, the water content can be simultaneously removed by pulverizing the waste activated carbon, thereby eliminating the need for a drying step conventionally required for reusing waste activated carbon discarded from a water treatment facility. can do.

In addition, by spraying water during storage of waste activated carbon, it is possible to remove harmful substances and the like adsorbed on the waste activated carbon, so that generation of harmful exhaust gas during combustion of the waste activated carbon can be suppressed, and secondary pollution will not occur. Waste activated carbon can be reused.

In addition, by sharing the existing coal storage space and coal yard storage space at coal-fired power plants, etc., the need to secure a separate space for storing a large amount of waste activated carbon is eliminated, and waste activated carbon can be easily reused. can do.

Furthermore, since the coal storage space adjacent to the combustion facility is used and pulverized at a place where the coal is reused, the difficulty of transporting the pulverized waste activated carbon can be solved, and the waste activated carbon can be easily reused.

Furthermore, by storing waste activated carbon and coal together in a coal storage or the like, the amount and frequency of watering for preventing spontaneous ignition of coal can be reduced.
Further, when low-grade coal is used as the coal, it is possible to assist the lack of heat of low-grade coal combustion.

Furthermore, when the mixture is burned together with the low-grade coal as the coal, the amount of the low-grade coal required to obtain the desired calorific value can be reduced. As a result, the amount of generated dust and SOx can be reduced.

Preferred embodiments of the present invention will be described with reference to the drawings.
According to the present invention, as shown in FIG. 1, storage means 2 for storing waste activated carbon and coal together, pulverizing means 4 for pulverizing waste activated carbon and coal, pulverized waste activated carbon and coal And a combustion means 6 for burning pulverized coal comprising: a heat recovery and reuse system 1 for waste activated carbon. It is preferable that the storage means 2 further includes a watering means 8 for watering the waste activated carbon and the coal. Further, it is preferable to include a wastewater treatment means 10 for treating water from the watering means 8 sprinkled on the waste activated carbon and coal, and it is more preferable to circulate water from the wastewater treatment means 10 to the watering means 8. .

に お い て In the present invention, it is preferable that the storage means 2 is provided close to the combustion means 6. As the storage means 2, a coal storage yard, a coal yard or the like installed in a coal-fired power generation facility or the like can be preferably mentioned.

Preferred examples of the pulverizing means 4 include a ball mill such as a rolling ball mill and a vibrating ball mill, and a general pulverizer such as a roller mill, a rod mill and a hammer mill. In particular, a rolling ball mill and a vibrating ball mill are suitable for pulverizing. is there.

Examples of the combustion means 6 include a general coal combustion furnace such as a commercial or private coal-fired power generation facility, a steam generating boiler, a cement manufacturing kiln, and a pyrolysis furnace.
The water spraying means 8 is not particularly limited as long as it can spray the treated water stored in the treated water tank of the wastewater treatment facility onto the surface of the coal or the waste activated carbon in the coal storage yard. For example, the treated water pumped by a pump may be discharged from a watering nozzle, a spray nozzle, or a perforated pipe having a plurality of holes formed in a pipe. The mode of watering may be intermittent or continuous.

As the wastewater treatment means 10, a coagulation / sedimentation treatment means or a combination of coagulation / sedimentation treatment and filtration can be preferably mentioned. As the coagulation sedimentation treatment, a preferred embodiment is one in which an inorganic coagulant such as PAC (polyaluminum chloride) is added to wastewater, and solid-liquid separation is performed in a gravity sedimentation tank to obtain treated water. As the filtration, an embodiment in which SS (floating matter) is removed by passing coagulated sedimentation treatment water through a filtration tank made of sand or the like can be preferably mentioned. In the case where a spray nozzle is used as the water spraying means 8, it is preferable that the wastewater treatment means 10 includes filtration in order to prevent clogging of the nozzle.

Next, a method for reusing waste activated carbon when the system for recovering and recycling waste activated carbon of the present invention shown in FIG. 1 is used will be described.
The waste activated carbon discarded from the gas treatment facility and / or the water treatment facility is transported to a storage means 2 such as a coal storage, and stored together with coal such as low-grade coal stored in the storage means 2. During storage, water is intermittently sprinkled from the sprinkling means 8 onto the waste activated carbon and coal. Next, the waste activated carbon and the coal are supplied together to the pulverizing means 4 such as a pulverizer, and pulverized while removing water content using frictional heat to obtain pulverized coal. When the obtained pulverized coal is supplied to a fuel facility 6 such as a boiler and burned, it becomes steam. The steam is reused for heat recovery by directly using it in the production process or by converting the energy into electric power using a heat exchanger. The water sprinkled on the waste activated carbon and the coal stored in the storage means 2 by the watering means 8 is recovered through the wastewater treatment means 10, recirculated to the watering means 8, and again stored waste activated carbon and the coal Sprinkled on

FIG. 2 shows an outline of decomposition / removal of a component to be adsorbed and / or a drug impregnated from waste activated carbon during storage.
When water is sprinkled from the watering means 8 onto the waste activated carbon accumulated on the coal in the storage means 2, the water-soluble components of the adsorbed components and the impregnated chemicals adsorbed in the waste activated carbon are washed away with water. And removed from the waste activated carbon pores. In the pores of the waste activated carbon, the components to be adsorbed and the impregnated chemicals are oxidatively decomposed by the action of microorganisms to form stable water-soluble sulfates and nitrates. Removed from the hole. By thus removing the components to be adsorbed and the impregnated chemical in advance, it is possible to prevent the generation of harmful substances such as sulfur oxides when burning the waste activated carbon.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

廃 Waste activated carbon was collected from the advanced treatment equipment at the water treatment plant. Table 1 shows the properties of this waste activated carbon and the properties of bituminous coal produced in Australia.

100 100 g of wet activated carbon in a wet state was pulverized for 15 minutes by a ball mill (TI-100 manufactured by CMT). The water content of the crushed waste activated carbon was about 8%. A 20 g sample of a mixture of pulverized waste activated carbon and similarly pulverized Australian coal (bituminous coal) was placed in a magnetic dish and burned for 1 hour in a 900 ° C. electric furnace in an air atmosphere. After the combustion, the ash content was weighed, and the sulfur oxide concentration (in 300 liters of electric furnace exhaust gas) was measured with a Kitagawa type detector tube (No. 5M, No. 5La, No. 5Lb) manufactured by Gastech. Table 2 shows the results.

When the waste activated carbon and bituminous coal were mixed and burned, the ash content of the combustion residue was less than half that of bituminous coal alone, and the sulfur oxide concentration was reduced to 3/4 that of bituminous coal alone. That is, it can be seen that by mixing and burning waste activated carbon and coal, both ash and sulfur oxides can be preferably reduced.

An experiment was conducted to decompose and remove adsorbed odor components (methyl sulfide and methyl disulfide) from waste activated carbon collected from the deodorizer of the sludge treatment facility at the sewage treatment plant.
10 mg / L of ferrous sulfate, 20 mg / L of sodium dihydrogen phosphate, and 10 mg / L of urea were dissolved in tap water to prepare a solution for watering.

(4) 1000 g of waste activated carbon was put into a sieve having an opening of 1 mm, and 50 mL of a watering solution was sprayed on the surface of the waste activated carbon several times a day. The temperature of the waste activated carbon layer was 16 to 25 ° C. Three weeks later, the pH of the residual solution for watering that had passed through the waste activated carbon was lowered to 4. The same operation was performed for another week.

Table 3 shows the results of measuring the properties of the waste activated carbon before and after the experiment.

From Table 3, it can be seen that the odor components (methyl sulfide and methyl disulfide) adsorbed on the waste activated carbon were removed well by sprinkling water before pulverizing the waste activated carbon.
Next, the waste activated carbon from which the odor component was removed by water sprinkling was pulverized, mixed with bituminous coal pulverized in the same manner as in Example 1, a mixed sample was prepared, and a combustion experiment was performed in an electric furnace. Table 4 shows the results.

わ か る It can be seen that when waste activated carbon and bituminous coal are mixed and burned, the ash as a combustion residue is lower than that of bituminous coal alone, and the sulfur oxide concentration is lower than that of bituminous coal alone. Further, as compared with Example 1, the sprinkling of water makes the sulfur oxide concentration after combustion extremely low (1/7) even in the case of waste activated carbon alone, and the effect of removing sulfur components by watering can be confirmed.

５ Table 5 shows the properties of waste activated carbon collected from the advanced treatment facility at the water treatment plant and brown coal (low-grade coal) produced in China.

(4) 100 g of the waste activated carbon in a wet state was pulverized by a ball mill (CMT Corporation TI-100) for 15 minutes. The water content of the crushed waste activated carbon was about 8%. Similarly, the brown coal was pulverized, and the pulverized waste activated carbon and the brown coal were mixed at a ratio shown in Table 6 to obtain a pulverized coal sample of 200 g. A 200 g pulverized coal sample was placed in a magnetic dish and heated at 750 ° C. for 2 hours in an electric furnace in an air atmosphere. The ash content (combustion residue) of the sample after the combustion treatment was weighed, and the sulfur oxide concentration in 300 L of the electric furnace exhaust gas was measured using a Kitagawa detector tube (No. 5M, No. 5La, No. 5Lb) manufactured by Gastech. Table 6 shows the results.

よ り From Table 6, it can be seen that when pulverized coal samples of waste activated carbon and low-grade coal (brown coal) are burned, the generation of unburned matter is smaller than in the case of low-grade coal alone.

A mixture of waste activated carbon in a dry state and bituminous coal (high-grade coal) or lignite (low-grade coal) is pulverized in the same manner as in Example 3, and is crushed with a thermostat type B calorimeter (based on JIS M8814-1985). The higher heating value was measured. Table 7 shows the results.

From Table 7, the mixture of waste activated carbon and bituminous coal (high-grade coal) showed a substantially constant high calorific value of 7300 to 8000 kacl / kg, regardless of the mixing ratio of waste activated carbon and bituminous coal. In the mixture of coal and brown coal (low-grade coal), the higher the mixing ratio of waste activated carbon, the higher the heating value.

Accordingly, in the present invention, when low-grade coal was used as the coal, it was confirmed that the higher calorific value can be increased by using the waste activated carbon, and the waste activated carbon can be reused for heat recovery.

FIG. 1 is a schematic explanatory view showing a schematic flow of a method for heat recovery and reuse of waste activated carbon of the present invention. FIG. 2 is a schematic explanatory view of a step of decomposing and removing a component to be adsorbed by water spray according to the present invention.

Explanation of reference numerals

1: Heat recovery and reuse system for waste activated carbon 2: Coal storage (storage means)
4: Pulverizer (pulverization means)
6: Boiler (combustion means)
8: Watering means 10: Wastewater treatment means

Claims (8)

(4) A method for heat recovery and reuse of waste activated carbon, comprising pulverizing waste activated carbon and coal, and supplying a mixture of the pulverized waste activated carbon and coal to a coal burning means for combustion. The heat recovery and reuse method for waste activated carbon according to claim 1, wherein the waste activated carbon is waste from a gas treatment facility and / or a water treatment facility. The heat recovery and reuse method for waste activated carbon according to claim 1 or 2, wherein the waste activated carbon is accumulated in a coal storage of the coal burning means, and then the waste activated carbon and the coal are pulverized. . Before pulverizing the waste activated carbon, water is sprayed on the waste activated carbon to remove adsorbed components and / or impregnated chemicals adsorbed on the waste activated carbon. The method for heat recovery and reuse of waste activated carbon according to any one of the preceding claims. The heat recovery and reuse method for waste activated carbon according to any one of claims 1 to 4, wherein the coal is a low-grade coal. Storage means for storing waste activated carbon and coal together, pulverizing means for pulverizing waste activated carbon and coal, and combustion means for burning pulverized coal comprising pulverized waste activated carbon and coal Heat recovery and reuse system for waste activated carbon. 7. The heat recovery and reuse system for waste activated carbon according to claim 6, wherein the storage means further includes a water sprinkling means. The heat recovery / reuse / recovery system for waste activated carbon according to claim 6 or 7, wherein the storage means is an existing coal storage space provided close to the combustion means.

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