JPH1119532A - Crushing method for bulky refuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out the safety operation for a bulky refuse crushing facility at low cost. SOLUTION: When a bulky refuse is crushed by using a crusher 10, exhaust gas is introduced in as purge gas to carry out the crushing while the atmosphere oxygen concentration in the crusher 10 is set in at most the lower limit of explosion. Preferably crushing is carried out while exhaust gas from an incineration ash melting furnace 1 operated by oxygen burning a fuel is introduced into the crusher 10. The oxygen concentration of exhaust gas from the incineration ash melting furnace 1 for oxygen burning is 1-2% or less, and the exhaust gas is functioned particularly effectively as purge gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for crushing bulky refuse, and more particularly to a method for crushing bulky refuse at low cost and capable of easily suppressing the risk of explosion during crushing.

[0002]

2. Description of the Related Art With the advancement of sophistication and complexity of the industry, the amount of oversized garbage including industrial waste has become enormous, and from the viewpoint of protecting the natural environment and suppressing pollution, the collection and disposal The method is an urgent task. Landfill and incineration (melting) are performed depending on the type of disposal, but non-combustible waste such as household appliances such as refrigerators and televisions have large shapes and can be used as they are. Since landfilling, incineration, and melting are difficult, usually, first, a dismantling operation by a tower loader or a process of being charged into a crushing machine such as a bulky crusher to be finely crushed are performed.

[0003] Such oversized refuse may include high-pressure materials such as a pressure tank storing a refrigerant, a high-pressure material such as a cathode ray tube, and even those that explode or ignite during crushing, such as a spray can. In order to avoid the danger of explosion or fire, bulky crushing facilities usually introduce inert gas or steam as a purge gas into the crushing machine during the crushing process (see 59-130544
JP, JP-A-5-309290, JP-A-6-2
26137, etc.).

[0004] Inert gas is separately purchased and used for that purpose, and steam is also obtained therefrom by installing a separate boiler in the facility. FIG. 5 illustrates an example of a conventional oversized refuse crushing facility. The oversized refuse crushing facility 10 includes a dedicated boiler facility 20 for generating steam. At the same time as the collected oversized refuse is charged into a processor (not shown), the steam generated by the boiler 20 is introduced as a purge gas. In addition, when a bulky waste crushing treatment facility is provided in a waste cleaning plant, part of steam for power generation and air conditioning may be used as a purge gas, but even in this case,
It needs a reasonable cost.

[0005] On the other hand, general incineration technology has also been advanced, and large amounts of incineration ash are generated in ordinary incineration, which makes landfilling a problem. A so-called melting furnace system, which makes ash detoxified and recycled at the same time as slag, is also being introduced in the waste disposal field. Various types of refuse melting / melting furnaces have also been proposed (see JP-A-4-84012, JP-A-5-296425, etc.), and heat is obtained by combustion with fuel and air having a high oxygen concentration. Municipal solid waste incineration ash melting furnaces are also being put into practical use.

[0006]

The crushing of oversized refuse in a waste cleaning plant requires the operation of a boiler as an incidental facility, or a part of steam for power generation and air conditioning, as described above. Has led to soaring prices. On the other hand, due to the decrease in oxygen cost, combustion using fuel and oxygen (or air with high oxygen concentration), especially natural gas oxyfuel combustion, is used in the municipal solid waste incineration ash melting furnace, which is part of the waste treatment system. I am trying to be. This exhaust gas is 12
It has high energy of over 00 ° C, and if the energy can be recovered and used effectively, the cost of dissolving refuse incineration ash and the cost of refuse disposal can be reduced. Compared to normal fuel and air combustion, it is difficult to balance the cost of the exhaust heat recovery device invested with the amount of heat recovered from the exhaust gas, and the exhaust gas is discharged into the atmosphere after gas treatment.

According to the present invention, purging gas, which is indispensable for the explosion protection of the above-mentioned crusher for oversized garbage, is obtained at a low cost by effectively utilizing the exhaust gas from a municipal garbage incinerator or the like. The purpose is to reduce the cost of crushing waste.

[0008]

The method for crushing bulky waste according to the present invention for solving the above-mentioned problems is basically a method for crushing bulky refuse with a crushing machine as necessary. A method for crushing bulky garbage, in which a purging gas added with, is introduced into the crusher, and the crushing process is performed while the atmospheric oxygen concentration in the crusher is equal to or lower than the lower explosion limit (normally, 12% or lower). An exhaust gas is used as the purge gas. Preferably, the exhaust gas is exhaust gas from a refuse incinerator, a boiler, or the like, or exhaust gas having a low oxygen concentration by-produced during oxygen production by the PSA method, and combustion using fuel and air having a high oxygen concentration. Exhaust gas from an incineration ash melting furnace, etc. is used. Such exhaust gas has a sufficiently low oxygen concentration, easily keeps the atmosphere below the explosion lower limit, and can effectively function as a purge gas.

When the amount of oxygen does not reach the lower limit, water is added to the exhaust gas to increase the amount of water vapor and is introduced into the crusher. Exhaust gases such as those mentioned above, especially those from incineration ash melting furnaces that use combustion with fuel and oxygen-rich air, typically have high thermal energy, above 1200 ° C., and only add water to the exhaust gas. Can easily produce steam. Although there is no particular limitation on the water addition method for this purpose, for example, a water injection nozzle is installed in a flue of an incineration ash melting furnace or the like, and a mode of spraying water in a spray form or a pool filled with water is installed in the flue. The exhaust gas may flow along the surface, and the amount of water vapor in the exhaust gas may be increased by evaporating water from the water surface. Such a method can be easily implemented using a conventional flue, and is a preferred embodiment in view of ease of operation.

[0010] When the inside of the crushing machine has an atmospheric oxygen concentration equal to or lower than the lower limit of explosion, it is conceivable that an oxygen deficiency state occurs when an operator enters the crushing treatment facility room. In order to prevent this, an oxygen concentration sensor is installed in the crushing facility, and the signal from the sensor is linked with the door lock at the entrance to the crushing facility, and the above-mentioned bulky waste is removed. Perform crushing treatment. As a result, it is possible to prevent the worker from accidentally falling into an oxygen-deficient state.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail using preferred embodiments. FIG. 1 is a view for explaining an embodiment of a method for crushing bulky waste according to the present invention,
An example is shown in which the exhaust gas from the incineration ash melting furnace 1 using natural gas oxygen combustion is used as a purge gas. 2 and 3 are explanatory diagrams showing an example of the incineration ash melting furnace, and FIG. 4 is an explanatory diagram showing an example of a bulky crushing facility. In this embodiment, the incineration ash melting furnace 1 is a conventionally known combustion type incineration ash melting furnace, and the incineration ash of municipal solid waste and the like sent into the melting furnace 2 by the extruder 3 is a natural gas G as a fuel. It is melted and melted by exposing it to a high-temperature flame from a burner 4 to which oxygen O ₂ is supplied as an oxidizing agent, and is taken out as molten slag. A flue 5 is provided near the slag outlet, and the exhaust gas passes through the flue 5 and is introduced into the oversized refuse treatment facility 10.
The oxygen to be supplied to the burner 4 can be obtained by any method, but the one made by PSA (Pressure Swing Adsorption) is low cost and efficient.

The composition of the exhaust gas from this type of melting furnace is such that 1/3 is carbon dioxide and 2/3 is steam. That is, the composition of city gas is methane CH ₄ : 8
8.5%, ethane C ₂ H ₆ : 4.6%, propane C ₃ H
₈ : 5.4%, butane C ₄ H ₁₀ : 1.5%, which can be considered substantially as methane CH ₄ 100%. Natural gas (methane gas) and air (O ₂ : 21%, N ₂ : 7)
9%), CH ₄ + 2O ₂ + 7.52N ₂ → CO ₂ + 2H ₂ O +
A 7.52N _2, contains a large amount of nitrogen N ₂ component in the exhaust gas,
Although amount of exhaust gas is also large, the combustion of natural gas (methane) and oxygen _{(O 2), CH 4 +} 2O 2 → CO 2 + 2H 2 O , and the with the amount of exhaust gas is greatly reduced, the exhaust gas is substantially CO ₂ And only H ₂ O. That is, the oxygen concentration in the exhaust gas is about 1 to 2%, and the temperature is 120%.
0 ° C. or higher.

In the present invention, the exhaust gas is introduced into the crushing machine 30 of the bulky crushing facility 10. The bulky waste crushing facility 10 is partitioned by concrete walls 11, and a part of the side wall has a bulky waste inlet 10a at the ceiling.
Is provided. A crushing machine 30 of a conventionally known form is installed in the compartment, and the crushing machine 30 is connected to an entrance 31 connected to the oversized garbage inlet 10a, a rotating crushing hammer 32, an outlet 33, and the like. Be composed. An oxygen sensor 1 is provided in the crushing chamber 34 of the crushing machine 30.
5 are arranged.

Further, a discharge tip of the bulky dust carrying means 12 such as an apron feeder or a belt conveyor is located above the bulky waste inlet 10a, and a discharge end 33 of the crusher 30. Is provided with a belt conveyor 13 for discharging the crushed material. Further, a pipe 14 that penetrates through the concrete wall 11 and reaches the inside of the crushing chamber 34 of the crushing machine 30 is provided, and the exhaust gas from the incineration ash melting furnace 1 passes through the pipe 14 and the crushing chamber of the crushing machine 30 is provided. 34. The concrete wall 11 is provided with an entrance 17 for a worker.

An oxygen sensor 15a for detecting the indoor air concentration of the crushing facility 10 is also provided, and a signal from the oxygen sensor 15a is supplied to the crushing machine 30 described above.
Is transmitted to the control device 16 together with a signal from the oxygen sensor 15 disposed in the crushing chamber 34 of the above. The oxygen sensor 15
Is constantly detecting the amount of oxygen in the crushing chamber 34 during operation of the crushing machine 30, and when the oxygen concentration exceeds a specified value,
The amount of exhaust gas supplied from the pipe 14 is increased to ensure safety. On the other hand, the oxygen sensor 15a constantly detects the amount of oxygen in the room. When the oxygen amount is equal to or less than the specified value, the opening and closing of the entrance 17 to the crushing treatment facility 10 is locked to prevent entry into the room. Ensure worker safety at times.

In this facility 10, the oversized garbage is introduced into the crushing machine 30 by the carrying-in means 12, crushed by the crushing hammer 32 to a size of several cm to several tens cm, and then discharged by the belt conveyor 13. Is done. At the time of crushing, the exhaust gas from the incineration ash melting furnace 1 is introduced into the crusher 30. As described above, the exhaust gas from the incineration ash melting furnace 1 using natural gas oxyfuel combustion has an oxygen concentration of about 1 to 2% and can sufficiently function as a purge gas.

If the oxygen concentration of the exhaust gas to be introduced is not sufficiently low due to circumstances in the incineration ash melting furnace 1 or the crushing apparatus, water is added to the exhaust gas from the incineration ash melting furnace 1. For this purpose, as shown in FIG. 2, a water spray nozzle 6 may be provided in the flue 5 to spray water in a spray form, and as shown in FIG. w
May be provided, exhaust gas may flow along the surface of the pool 7, and the amount of water vapor in the exhaust gas may be increased by evaporation of water from the water surface. The exhaust gas is in a high temperature state of 1200 ° C., and the added water immediately becomes steam and functions as a purge gas. Also,
This addition of water also lowers the temperature of the exhaust gas and ensures safety.

In the above description, an example in which natural gas is used as the fuel has been described. However, even when oil such as kerosene or pulverized coal is used as the fuel for the incineration ash melting furnace 1, the oxygen is When combustion or high oxygen concentration air combustion is performed, exhaust gas having a low oxygen concentration is generated. Therefore, even when oil or pulverized coal is used as fuel and the exhaust gas obtained by burning it with oxygen or high-oxygen-concentration air is introduced into the crusher, the initial purpose is similarly achieved.

The purging gas is not limited to the exhaust gas containing a large amount of water vapor as long as the oxygen concentration in the atmosphere can be lower than the explosion limit, and is not limited to the exhaust gas from a refuse incinerator or a boiler. Alternatively, exhaust gas having a low oxygen concentration by-produced during oxygen production by the PSA method may be used. In this case as well, if the oxygen concentration in the exhaust gas is equal to or less than the lower limit of the explosion of the atmosphere, the intended purpose is achieved.

[0020]

As described above, according to the method for crushing bulky refuse of the present invention, the steam generated by a specially provided boiler is conventionally exhausted without being used as a purge gas. By using the exhaust gas as the purge gas, safe operation of the oversized waste crushing facility can be performed, and the waste disposal cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for crushing bulky waste according to the present invention.

FIG. 2 is an explanatory view showing an example of an incineration ash melting furnace.

FIG. 3 is an explanatory view showing another example of an incineration ash melting furnace.

FIG. 4 is an explanatory view showing an example of a bulky crushing facility.

FIG. 5 is a diagram illustrating a conventional method for crushing bulky waste.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Incineration ash melting furnace using natural gas oxygen combustion, 2 ... Melting furnace, 3 ... Extruder, 4 ... Burner, 5 ... Flue, 6 ... Water injection nozzle, 7 ... Water tank, 10 ... Large garbage crushing facility , 30: crushing machine, 20: boiler, G: gas, O
₂ ... oxygen, w ... water

Claims (7)

[Claims] When crushing the collected oversized refuse with a crusher, a purge gas and, if necessary, steam are introduced into the crusher to reduce the atmospheric oxygen concentration in the crusher below the lower explosion limit. A method for crushing bulky waste, wherein exhaust gas is used as a purge gas, wherein the crushing process is performed while performing the crushing process. 2. The method for crushing bulky waste according to claim 1, wherein said exhaust gas is exhaust gas from a waste incinerator. 3. The method according to claim 1, wherein the exhaust gas is a boiler exhaust gas. 4. The method according to claim 1, wherein the exhaust gas is exhaust gas from an incineration ash melting furnace using combustion with fuel and air having a high oxygen concentration. 5. The method for crushing bulky waste according to claim 1, wherein the exhaust gas is an exhaust gas having a low oxygen concentration by-produced during oxygen production by the PSA method. 6. The method for crushing bulky waste according to claim 5, wherein air having an oxygen concentration of 90% or more by a PSA method is used as an oxidizing agent for combustion in the incineration ash melting furnace. 7. A method for crushing oversized garbage in a state where an oxygen concentration sensor is installed in the crushing facility and a signal from the sensor is linked to a door lock at an entrance to the crushing facility. The method for crushing bulky waste according to any one of claims 1 to 6, wherein: