JPH11267603A - Treatment of waste and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a continuous operation of an incinerator and to suppress a discharge of a harmful material by providing the first stage in which the waste such as city waste is crushed and screened, slaked lime is added, and the mixture is dried to form a powdery particle and the second stage in which the powdery particle is burned to generate steam and utilizing a part of the generated steam as a heat source for drying. SOLUTION: The city waste 1 is crushed by a crushing/screening machine 2 to screen and remove metals 3 such as iron, aluminum, etc., then the slaked lime supplied from an addition device 31 is added and dried with a drying device 5 to form the dried powdery particle 6 hardly causing putrefaction and malodor, and the particle 6 is stored in a storage tank 7. Then the particle 6 is burned in a combustion furnace 8 and the steam is generated in a boiler 10 by this combustion gas. A waste gas 15 is discharged to atmosphere after being treated at a waste gas treating stage 11. The generated steam 12 is used for an electricity generation and other heat utilization at a steam utilizing device 13 and also a part of the steam 21 is used as a drying heat source of the drying device 5, and the waste gas 22 of the drying device 5 is burned in the boiler 10 to deodorize and detoxicate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating waste such as municipal waste.

[0002]

2. Description of the Related Art Among wastes such as municipal waste, those that can be incinerated are reduced in weight by incineration. Municipal solid waste incinerators are operated on a municipal basis and have a processing volume of 50%.
Less than tons / day of incinerators account for 50% of facilities. The municipal solid waste incinerator having such a throughput employs a mechanized batch furnace operating for 8 hours a day or a small-scale intermittent operation furnace for a semi-continuous processing furnace operating for 16 hours a day. In such conventional municipal waste incineration technology, intermittent operation is performed every day with shutdown of refuse incineration. It is very difficult to achieve emission control only with combustion optimization technology. For this reason, it is necessary to install a pollution control device, and the cost required for this is increased. In small and medium-sized processing furnaces, installing a pollution control device is not cost-effective.

[0003] Therefore, instead of incinerating waste such as municipal waste, the flammable components are recovered as pellet-shaped waste molding fuel (RDF) through a crushing and molding process and used as fuel for large-scale combustion equipment and the like. By doing so, techniques have been developed to avoid the problems of small-scale intermittent incineration operations. In this case, a step of forming the pellets after the refuse is dried and pulverized is required.

In the process of drying waste such as municipal solid waste, kerosene is conventionally used in a drying heat source generator.
In addition, a deodorizing furnace is provided for deodorizing and detoxifying generated gas generated from the drying process, and kerosene is used as a heat source. Under such circumstances, a municipal solid waste treatment apparatus as shown in FIG. 3 has been proposed as a technique for controlling the emission of dioxins to achieve environmental conservation and recycling energy resources. In the municipal solid waste treatment apparatus shown in FIG. 3, municipal solid waste 1 is crushed 2, and iron, aluminum and the like 3 are selectively removed, dried 5, dried garbage 6 is burned in a combustion furnace 8, and combustion gas 9 is boiled. The steam 12 is introduced into the steam generator 10, and the steam 12 is used in the steam utilization device 13. The drain 14 is returned to the boiler 10, and the flue gas 15 is discharged to the atmosphere after the exhaust gas treatment 11. In this process, kerosene 41 is used as a heat source in drying step 5 of municipal solid waste,
The heat 43 is supplied to the drying step 5, and the exhaust gas 44 discharged from the drying step 5 is treated in a deodorizing furnace 45 using kerosene 46 to be radiated into the atmosphere.

Japanese Patent Application Laid-Open No. 8-332496 discloses a manufacturing apparatus for manufacturing solid fuel from waste such as municipal solid waste, a solid fuel storage, a combustion apparatus for burning solid fuel, steam, Disclosed is an integrated combined system that includes a boiler that generates hot water and generates energy such as steam, hot water, and electric power, and uses steam or hot water as a heat source for heating a mixed heating reactor of a solid fuel production device. Are also disclosed.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the technology for treating the above-mentioned waste such as municipal solid waste. The objects of the present invention are as follows. (A) Waste such as municipal solid waste is converted to pelletized fuel (R
Without the treatment up to DF), the molding step is omitted, and preservative and deodorant treatments are applied to obtain a dry powder that can be stored.

(B) The dry powder is continuously burned for 24 hours to overcome the difficulty of controlling harmful emissions from an incinerator by intermittent operation of conventional municipal waste incineration. (C) Steam is generated from the combustion process, a part of which is used in the drying process, and the use of kerosene as a drying heat source is unnecessary. (D) The gas generated from the drying step is sent into the atmosphere of the combustion step, and the use of kerosene for deodorization and detoxification is stopped.

[0008] By the above (a) and (b), equipment costs are reduced, emission of harmful substances is suppressed, and rationalization is achieved. According to the above (c) and (d), use of kerosene is eliminated, waste is effectively used, and energy consumption is reduced.

[0009]

The present invention is characterized by taking the following technical means in order to achieve the above object. The first aspect of the present invention is the first method of crushing, sorting, adding slaked lime, drying and storing powdered municipal solid waste.
And a second step of burning the powder and granules to generate steam and utilizing heat, wherein a part of the generated steam is used as a heat source for drying. Is the way.

In this case, in the second step, if a steam turbine is used and a part of the steam is extracted from an intermediate stage of the steam turbine, steam at an appropriate pressure can be used. Low-pressure stage is rational and energy-economically favorable. In addition, it is preferable that the generated gas generated during the drying be sent into a combustion atmosphere in which the powder and granules are burned to be deodorized and made harmless, because the use of kerosene for this purpose can be eliminated.

Further, the first step may be an intermittent operation, for example, an operation for 8 hours a day.
By performing the continuous operation for four hours, it is possible to eliminate the transient unsteady operation at the start and end of the operation of the combustion process, and to prevent the emission of harmful substances. In addition, rationalized operation such as automation and unmanned operation becomes possible. In addition, it is possible to reduce the size of the device in the second step, and it is possible to reduce equipment costs.

[0012] The apparatus of the present invention capable of suitably carrying out the above method is a first processing apparatus comprising a crushing apparatus for waste such as municipal waste, a sorting apparatus, a slaked lime adding apparatus, a drying apparatus and a storage apparatus. And a second processing device including a combustion device for the powder and granules, a steam generation device, and a heat utilization device,
An apparatus for treating waste, comprising a system for supplying a part of steam generated from a steam generator to the drying device.

In this case, the processing capacity per unit time of the second processing unit is 1 / (1.5 to 3) with respect to the processing capacity per unit time of the first processing unit. By operating continuously with a small device, the device can be made inexpensive. In addition, by setting the storage capacity of the storage device to a capacity corresponding to the period of the periodic repair of the second processing device, it is possible to use only one system without using a plurality of second processing devices, Capital investment can be reduced.

[0014] The amount of slaked lime added is such that preservative and deodorant effects are obtained, and waste can be stored for a long period of time. In this storage, the upstream side of the storage stage, that is, the capacity of the apparatus for producing dry granules is set to a scale suitable for operation for 8 hours a day, and the downstream side, that is, the combustion capacity of the dry granules is set to a scale suitable for 24 hours operation. The capacity as a buffer for In this case, the downstream processing capacity corresponds to continuous operation,
Eliminates unsteady operation that accompanies starting and stopping due to intermittent operation,
Reduce emissions of dioxins and other harmful substances, and automate, increase efficiency, and reduce the size of plants through continuous operation.

[0015] The storage capacity is set to a magnitude corresponding to the storage amount during the suspension period in the periodic repair or the like in the downstream process. For this purpose, preservation, deodorization, and prevention of qualitative change of the granular material during the storage period necessary for the purpose are aimed at. In order to enable such a long-term storage of the powder and granules, it is important to appropriately add slaked lime to reduce the water content of the powder and granules. In addition, by securing the storage capacity corresponding to this regular repair period, it is possible to eliminate the equipment of multiple lines in the downstream process, and it is sufficient to provide a single line of equipment with the appropriate combustion processing capacity, thus reducing equipment costs and operating operations. Simplification and automation can be achieved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a process chart showing a waste disposal method according to an embodiment of the present invention. The municipal solid waste 1 is crushed by a crushing / sorting device 2 to sort and remove iron, aluminum, or an alloy thereof 3 and the like, and slaked lime supplied from a slaked lime adding device 31 is added thereto. Granule 6
Becomes The dry powder 6 has a water content of 10% by weight or less and contains about 1% by weight of slaked lime, thereby preventing decay and odor, can be stored for a long time, and is stored in the storage tank 7. The dry powder 6 is burned in a combustion furnace 8, and a combustion gas 9 is guided to a boiler 10, where steam is generated. The exhaust gas 15 is treated in the exhaust gas treatment step 11, rendered harmless, and released into the atmosphere. The steam 12 is used for power generation and other heat utilization by a steam utilization device 13. Some of the steam 21 is used as a drying heat source in the drying step 5.
The exhaust gas 22 generated from the drying step 5 is introduced into the combustion chamber of the boiler 10, where it is deodorized and detoxified by burning and thermal decomposition. Since it is not necessary to use kerosene for the deodorization of the heat source in the drying step 5 and the exhaust gas 22 in the drying step 5, it is possible to save external energy and achieve efficient and efficient use of waste.

Further, by forming the municipal solid waste 1 into a dry granular material 6 that can be stored and burning it, it is possible to omit a molding process for obtaining a solid refuse molding fuel, thereby reducing capital investment, reducing electric power, It is possible to save human power. Further, the apparatus after the combustion furnace 8 can be operated continuously, and the emission of harmful components accompanying the intermittent operation can be easily suppressed. Further, since the dry powder can be stored in the storage tank 7, the upstream process up to the dry powder production can be performed for a short period of time intermittently, for example, 8 hours a day, regardless of the operation of the downstream process. It is possible. Further, the downstream process after the combustion furnace is a device requiring periodic repair of a boiler or the like. However, by providing the storage tank 7 with a storage capacity of an amount during the suspension period of the periodic repair, the downstream process can be performed. The devices can be in a series.

In the embodiment shown in FIG. 2, the apparatus for burning the dry powder 6 is provided with a gasification ash melting furnace 32 for waste, which gasifies the powder to gas fuel, and converts the ash to slag 33. The gas is discharged and supplied to the combustion boiler 10 for combustion. The steam 12 generated from the boiler 10 generates electric power by a steam turbine 34 and a generator 35. Part of the steam 21 extracted from the intermediate stage of the steam turbine is
Sent as a heat source for drying. The waste gas 22 generated from the drying device 5 is sent to the combustion chamber of the combustion boiler,
Deodorize and detoxify. As described above, this system becomes highly efficient. In addition, the combustion device of the dry powder is not limited to the combustion furnace shown in FIG. 1 and the gasification ash melting furnace for waste shown in FIG. 2, but a combustion boiler of a type for burning the dry powder, For example, a fluidized bed boiler may be used.

[0019]

According to the present invention, waste such as municipal solid waste is subjected to antiseptic and deodorizing treatments, stored as dry powder that can be stored, and the dry powder is continuously burned for 24 hours to generate steam. Since the heat is generated and the heat is used by performing power generation, etc., it is possible to omit the molding process for producing a pellet-shaped molded fuel (RDF), to reduce the size of the apparatus after the combustion process, and thus to reduce the capital investment. Harmful substances can be effectively suppressed. Also, the use of kerosene as a drying heat source is unnecessary, and the gas generated from the drying process is sent into the combustion process atmosphere, and deodorization is performed without using kerosene
Harmless.

As described above, by reducing equipment costs, suppressing emission of harmful substances, and not using kerosene, it is possible to effectively utilize waste such as municipal waste and reduce energy consumption.

[Brief description of the drawings]

FIG. 1 is a process chart showing a waste disposal method according to an embodiment.

FIG. 2 is a process chart showing a waste disposal method according to an embodiment.

FIG. 3 is a process chart showing a conventional waste treatment method.

[Explanation of symbols]

 Reference Signs List 1 municipal waste 2 crushing (crushing / sorting device) 3 iron, aluminum, etc. 5 drying (process) (drying device) 6 dried refuse 7 storage tank 8 combustion furnace 9 combustion gas 10 boiler 11 exhaust gas treatment (process) 12 steam 13 steam Utilization device 14 Drain 15 Combustion exhaust gas 21 Partial steam (extraction) 22 Drying furnace exhaust gas 31 Slaked lime addition device 32 Gasification ash melting furnace 33 Slag 34 Steam turbine 35 Generator 41 Kerosene 42 Heat source generating furnace 43 Heat 44 Exhaust gas 45 Deodorizing furnace 46 Kerosene

Claims (7)

[Claims] 1. A first step in which waste is crushed, sorted, slaked lime added, and dried to obtain a powder that can be stored, and a second step in which the powder is burned to generate steam and utilize heat. Consisting of
A method for treating waste, wherein a part of the steam is used as the heat source for drying. 2. A steam turbine is used for the heat utilization.
The method according to claim 1, wherein a part of the steam is extracted from an intermediate stage of a steam turbine. 3. The method for treating waste according to claim 1, wherein the generated gas generated during the drying is sent into a combustion atmosphere in which the powder and granules are burned, and deodorized and made harmless. . 4. The method according to claim 1, wherein the first step is an intermittent operation,
The method for treating waste according to any one of claims 1 to 3, wherein the process is a continuous operation. 5. A first treatment device comprising a waste crushing device, a sorting device, a slaked lime adding device, a drying device and a storage device, and a first treatment device comprising a combustion device, a steam generation device and a heat utilization device for the granular material. A wastewater treatment apparatus, comprising: a system for supplying a part of the steam generated from the steam generation apparatus to the drying apparatus. 6. The processing capacity per unit time of the second processing device is set to 1 / (1.5 to 3) with respect to the processing capacity per unit time of the first processing device. The waste disposal apparatus according to claim 5, wherein 7. The storage device according to claim 5, wherein the storage capacity of the storage device is set to a capacity corresponding to a periodic repair period of the second processing device, and the second processing device is provided in one line. Waste treatment equipment.