JPH10311677A - Method for drying garbage or industrial waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fully utilize the drying function of garbage or industrial waste and at the same time minimize a load for repairing and maintaining a drying device by adding a wall surface adhesion prevention material to the garbage or the industrial waste when indirectly heating and drying the garbage or the industrial waste. SOLUTION: Municipal garbage that is received by an upstream process and is crushed by a biaxial crushing machine is stored in a crushed object hopper 1 as crushed garbage 1, and then the crushed garbage 11 is fed into the drying container of an indirect-heating-type steam drying machine 3 via a fixed-amount supply equipment 2 that is attached to the crushed object hopper 1. In this case, a material 12 for preventing adhesion onto a wall surface is supplied to the crushed object hopper 1. For example, industrial slaked lime is used as the material 12 for preventing adhesion onto the wall surface, and the material for preventing adhesion onto the wall surface being stored in a silo is cut by a fixed amount using a rotary valve and is sent into the crushed object hopper 1 via a conduit with compression air being discharged from a blower for discharging the agent for preventing adhesion onto the wall surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drying refuse or industrial waste, and more particularly, to preventing refuse or industrial waste from adhering to a wall surface of a drying device in an indirect heating drying or moisture control step. About technology.

[0002]

2. Description of the Related Art In recent years, regarding the treatment of so-called municipal waste and industrial waste such as waste plastics discarded from ordinary households and various business establishments, trace toxic substances such as dioxins discharged from municipal waste incinerators. There is a demand for the creation of a waste recycling-based society because of the tightening of the emission standards, stricter requirements for environmental preservation, and tight landfill sites for waste and incinerated ash. Under these social conditions, local governments are increasingly motivated to introduce a solid fuel conversion plant for urban garbage.

Conventionally, many processes have been proposed for the process of converting municipal solid waste and industrial waste into a solid fuel, but the basic steps constituting such a process are a crushing step, drying or moisture control. There are four steps: a process, a sorting process, and a molding process. Of the four basic processes, the drying or moisture adjustment process has conventionally been performed by a method of directly heating combustion gas such as kerosene and refuse or industrial waste. A technology for indirect heating by steam generated from a boiler using solid fuel as a heat source has been introduced, and attempts have been made to rationalize energy consumption.

[0004]

However, when municipal solid waste is dried by the indirect heating process using steam as described above, the components contained in the municipal solid waste are transferred to a heat transfer surface such as a steam jacket to which the municipal solid waste contacts. A deposit as a main component is generated. These deposits are mainly derived from plastics, which become inclusions, and solids adhere to and solidify on the wall surfaces. This adhesion phenomenon is a problem peculiar to the indirect heating type steam drying method, and occurs under generally used steam conditions, for example, when the steam temperature is lower than 120 ° C to 200 ° C. It is a phenomenon that cannot be seen. In addition, the deposit itself has high hardness and exhibits strong adhesiveness to the heat transfer surface, which hinders heat transfer performance. Also,
Such deposits gradually grow as time elapses in the drying operation of dust and the like. When the continuous operation of the steam dryer is performed without removing such deposits, the heat transfer efficiency deteriorates with time, the drying capacity of the steam dryer decreases, and it is necessary to achieve the rated amount of drying treatment. It will be difficult.

[0005] For example, in a steam dryer having a vertical cylindrical casing provided with a vertical rotary stirring device inside and a steam jacket on the casing wall, the tip of the stirring blade of the rotary stirring device and the drying vessel are provided. If the gap with the inner wall is only about a few mm, strong and sticky deposits generated from garbage or industrial waste and grown gradually fill this narrow gap,
Eventually, there is a problem that it comes into contact with the rotary stirring device and causes damage to the stirring blades or the motor of the stirring device.

An object of the present invention is to solve such a problem, to make the drying function of the refuse or industrial waste sufficiently effective, and to minimize the repair and maintenance of the drying apparatus.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and includes an indirect heating / drying method for adding waste preventing material to garbage or industrial waste. A method for drying garbage or industrial waste. Said indirect heating is particularly effective in the case of steam jacket heating. Note that the indirect heating is not limited to a heat transfer type or a heat transfer medium as long as it is an indirect heating method, but since a solid fuel produced in-house is used as a characteristic of this plant, the fuel is burned to generate steam in a boiler, It is most preferable to use this as a heating medium for steam jacket heating.

[0008] The above-mentioned wall-adhesion preventive material prevents dust from softening at a high temperature and increasing the tackiness, thereby reducing the tackiness,
It is a substance that prevents refuse or industrial waste from the drying process from adhering to the walls of the drying device. Such a wall surface adhesion preventive agent has a softening temperature of 300 ° C. or more and a maximum particle size of 1 mm.
It is effective to use the following powder. Specifically, the wall surface adhesion preventing material is selected from the group consisting of hydroxides or carbonates of alkaline earth metals, carbon powder, fly ash, silica fine powder, alumina fine powder, blast furnace slag and converter slag. Good results are obtained with one or more.

As alkaline earth metals, Ca, Ba,
Sr can be mentioned, but among them, Ca hydroxide or carbonate which is easily available and can be easily made into a fine powder is preferable. Carbon is preferable because it can easily obtain a powder, has a large adhesion preventing and lubricating effect, and finally becomes a fuel source. In addition, carbon has an effect of suppressing generation of dioxin from a substance containing sulfur, and porous carbon also has a performance of adsorbing odor components.
Pulverized coal is the most readily available carbon source. Fly ash is pulverized coal-burning coal ash from a thermal power plant or the like, and has a fine spherical shape and acts as a solid lubricant, so it is dispersed in garbage or industrial waste, facilitating stirring,
The effect of preventing wall adhesion is large with a small amount. Silica powder and alumina powder can also easily obtain micron-order ultrafine powder, have a good dispersibility, have a lubricating action in a viscous substance, and have an excellent wall adhesion preventing effect when used in a small amount. In addition, blast furnace slag and converter slag can be easily obtained, and at the same time, meet the demands for expanding their applications.

Next, the addition of the wall adhesion preventing material may be performed by mixing the waste or industrial waste into the waste or industrial waste before putting the waste or industrial waste into the heating device. It may be sprayed or blown with a carrier gas. Spraying in the vicinity of the wall surface of the drying device is efficient because it can be directly mixed with garbage or industrial waste that may adhere to the wall surface. In this case, it is preferable to use, for example, a structure provided with a swirling chute or the like utilizing the rotating motion of the swirling stirring blade. Further, if the material is mechanically discharged from the tip of the stirring blade of the drying device and sprayed or ejected together with the carrier gas, the material can be efficiently supplied to the most preferable position.

[0011] Further, the wall surface adhesion inhibitor can be sprayed as a slurry or a solution depending on the properties, and a desired amount can be easily and uniformly supplied to a desired position at a desired position. The addition amount of the wall surface adhesion preventing material may be increased or decreased according to the composition of the refuse or the industrial waste, or may be adjusted in conjunction with the power consumption of the stirring device.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of a drying process for municipal solid waste according to an embodiment of the present invention. The municipal solid waste that has been received in the upstream process not shown and crushed by the twin-screw crusher is stored in the crushed product hopper 1 as crushed solid waste 11. Thereafter, the crushed refuse 11 is fed into the drying container of the indirect heating type steam drying device 3 via the quantitative supply device 2 attached to the crushed product hopper 1. The drying device 3 is a batch type drying device having a built-in stirring device 4 having vertical stirring blades. The drying device 3 dries the supplied crushed refuse 11 and discharges it from the discharge port 6 to the next step. The drying device 3 has a steam jacket 5 for indirect heating, and supplies steam 21 to the steam jacket 5. The drain 22 after the heat exchange is discharged outside.

The crushed product hopper 1 has a wall-adhesion preventing material 12
Is supplied. In this example, industrial slaked lime was used as the wall surface adhesion preventing material 12. This slaked lime has a particle size of 100μ
m or less, having no softening property. The supply of the wall adhesion inhibitor is performed by cutting out a fixed amount of the wall adhesion inhibitor stored in a silo (not shown) using a rotary valve, and using a compressed air injected from a wall adhesion inhibitor spray blower via a conduit to form a crushed product hopper 1. Sent inside.

The amount of the wall-adhesion preventive agent to be fed into the crushed product hopper is adjusted by adjusting the number of rotations of the wall-adhesion preventive agent supply rotary valve based on the signal of the amount of the crushed garbage sent from the quantitative feeder 2 to the drying device 3. As a result, the wall surface adhesion inhibitor was fed to the crushed product hopper at a constant weight ratio with respect to the actual value of the amount of crushed refuse 11 sent to the drying device 3. The addition amount of the wall surface adhesion inhibitor has an appropriate value depending on the type of garbage and the like, but in an example of municipal garbage, a sufficient adhesion preventing effect can be obtained by adding 5% by weight or less on a refuse moisture supply basis.

It is preferable that the crushed refuse 11 and the wall surface adhesion preventive agent charged into the crushed product hopper 1 are formed into a homogeneous mixture before being sent to the drying device 3. For this reason, it is preferable to use a screw feeder as the discharge fixed quantity supply device 2 of the crushed product hopper 1. Further, it is also possible to directly prevent the wall adhesion by spraying the wall adhesion inhibitor near the inner wall surface in the container of the drying device 3, and in this case, the spraying is performed by using the turning of the stirring device 4. It may be that.

[0016]

As described above, according to the method for drying garbage or industrial waste of the present invention, when drying garbage or industrial waste or adjusting the water content, the refuse or industrial waste is charged into a drying device or a moisture adjusting device. By adding the anti-fouling material to the refuse or industrial waste, it is possible to prevent the generation of the filth or industrial waste-containing fouling in the drying device or the moisture control device. it can. As described above, the self-produced fuel of the solid fuel conversion plant from garbage or industrial waste can be effectively used for the operation process of the plant, contributing to the reduction of plant construction and maintenance costs, and rational design. And achieve an excellent effect that the operation can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic flow chart of a drying apparatus of an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crushed product hopper 2 Quantitative discharge device 3 Drying device 4 Stirrer 5 Steam jacket 6 Discharge port 11 Crushed refuse 12 Wall adhesion prevention material 21 Steam 22 Drain

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuneo Aihara 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Kawasaki Steel Corporation (72) Inventor Fumihiro Miyoshi 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Saki Steel Corporation

Claims (8)

[Claims] 1. A method for drying garbage or industrial waste, comprising adding an anti-fouling material to the garbage or industrial waste when indirectly heating and drying the garbage or industrial waste. 2. The method for drying refuse or industrial waste according to claim 1, wherein the indirect heating is steam jacket heating. 3. The material for preventing adhesion to a wall has a softening temperature of 300.
The method for drying garbage or industrial waste according to claim 1 or 2, wherein the powder is a powder having a maximum particle size of 1 mm or less at a temperature of not lower than 1 ° C. 4. The one or more selected from the group consisting of hydroxides or carbonates of alkaline earth metals, carbon powder, fly ash, silica fine powder, alumina fine powder, blast furnace slag and converter slag, wherein the wall surface adhesion preventing material is selected from the group consisting of: The method for drying garbage or industrial waste according to any one of claims 1 to 3, wherein the method is two or more types. 5. The method according to claim 1, wherein the wall-adhesion preventing material is mixed with the refuse or industrial waste before the refuse or industrial waste is put into the drying step. How to dry garbage or industrial waste. 6. The method according to claim 1, wherein said wall surface adhesion preventing material is mechanically sprayed near a wall surface in the drying device.
4. The method for drying garbage or industrial waste according to any one of 4. 7. The method for drying garbage or industrial waste according to claim 1, wherein the wall surface adhesion preventing material is blown together with a carrier gas into the vicinity of the wall surface in the drying device. 8. The method for drying garbage or industrial waste according to claim 1, wherein the wall surface adhesion preventing material is sprayed as a slurry or a solution near a wall surface in a drying device.