JPH11257632A - Waste incineration method with reduced generation of harmful substances - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely restrain the occurrence of harmful substances during burning wastes by a method wherein a magnetic field is exerted to combustion air upon incinerating the wastes through combustion by supplying combustion air to the wastes in an incinerating furnace. SOLUTION: Wastes 2, brought by a waste collecting vehicle 1, is received in a waste pit 3, and is transported to a charging hopper 5 at the entering side of a combustion chamber by a crane 4 to move the waste 2 from the charging hopper 5 through a drying stoker 7, a combustion stoker 8 and a post- combustion stoker 9 sequentially by a feeder 6 whereby incineration is finished. In this case, a magnetic field treating device 11 is installed in the main pipe 10 of individual pipelines 7a, 8a, 9a, which guide air into the drying stoker 7, the combustion stoker 8 and the post-combustion stoker 9 respectively, to exert a magnetic field to the air, sent into respective pipelines 7a, 8a, 9a through the main pipe 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incineration method that suppresses the generation of harmful emissions such as hydrocarbons and dioxins, which are involved in the combustion of waste.

[0002]

2. Description of the Related Art The treatment of waste, which accounts for the majority of general waste, is mainly incineration. Specifically, waste is burned in an incinerator, and during this combustion, harmful substances such as hydrocarbons and dioxins are generated, and these harmful substances may be contained in ash and exhaust gas after combustion. It is a problem.

[0003] As a means for suppressing harmful substances generated by the combustion, a document titled "Technique for generating and suppressing combustion products" (supervised by Norio Arai, Techno System, 1997) discloses a method of stable complete combustion. Therefore, it was shown that securing oxygen, temperature and residence time during combustion, and that strengthening of mixing is effective, especially that dioxins are advantageous for high-temperature combustion, and as specific means, the shape of the combustion chamber Changes and introduction of various controls have been proposed.

[0004]

However, to increase the temperature, it is necessary to lower the air ratio. However, a decrease in the air ratio leads to incomplete combustion, and it is extremely difficult to achieve both high temperature combustion and complete combustion. Due to the difficulty, there is a limit in controlling harmful substances by these methods.

[0005] In addition, in the existing incinerator, changing the shape of the combustion chamber and introducing various controls requires a great deal of remodeling of the equipment and requires a great deal of cost. The limit is to deal with changing the conditions. However, since the generation of harmful substances cannot be sufficiently suppressed by changing the operating conditions, harmful substance control technologies that can be easily and inexpensively adopted in existing facilities are being sought.

Accordingly, the present invention proposes a novel waste incineration method that reliably suppresses the generation of harmful substances during waste combustion and is easily applicable to existing facilities. With the goal.

[0007]

Means for Solving the Problems The present inventors have intensively studied means for achieving complete combustion without increasing the air ratio in order to suppress the generation of harmful substances. It has been found that the combustion is promoted by installing a magnet in the pipe of the present invention, and the present invention has been completed.

That is, the present invention provides a method of supplying combustion air to waste in an incinerator, burning the waste, and incinerating the waste, in the process of guiding the combustion air to the waste in the incinerator. This is a method for incineration of waste, wherein generation of harmful substances is suppressed, characterized by applying a magnetic field to combustion air.

[0009]

Next, the method of the present invention will be described with reference to a stoker type incinerator which is a typical example of the incinerator shown in FIG.
This will be described in detail. Now, in the incinerator, the waste 2 brought in by the waste collection vehicle 1 is stored in the waste pit 3, and the waste 2 is transported by the crane 4 to the input hopper 5 on the entrance side of the combustion chamber, and Incineration is completed in the process of sequentially moving 2 from the charging hopper 5 via the feeder 6 on the drying stoker 7, the burning stoker 8, and the post-burning stoker 9. First, in the drying stoker 7, the waste 2 is dried by air supplied from below the grate, and the dried waste 2 moves on the movable part of the grate to form the grate of the next combustion stoker 8. Transported up. Then, the combustion stoker 8 burns the waste 2 with the combustion air supplied from below the grate. Further, the unburned matter remaining in the combustion stoker 8 is provided downstream of the combustion stoker 8 and then transferred to the combustion stoker 9, where it is placed on the grate to complete the combustion.

Here, the drying stoker 7 and the burning stoker 8
In the post-combustion stoker 9, it is important to apply a magnetic field to a pipe that guides air supplied from below the grate, particularly, combustion air supplied to the combustion stoker 8. That is, in the illustrated example, the drying stoker 7 and the burning stoker 8
In addition, a magnetic field treatment device 11 is installed in the main pipe 10 of each of the individual pipes 7a, 8a and 9a for guiding air to the post-combustion stoker 9, and air flowing through the main pipe 10 and sent to the respective pipes 7a, 8a and 9a A magnetic field. Reference numeral 12 denotes an air preheating device.

Here, a permanent magnet is used as the magnetic field processing device 11, and a pair of permanent magnets 11a and 11b are arranged on both sides of the main pipe 10 as shown in FIG. The magnetic field can be applied to the fuel or combustion air by passing the lines of magnetic force in the radial direction of. The arrangement of the permanent magnets is based on the arrangement shown in FIG. 2A, and the arrangement of each permanent magnet shown in FIGS. 2B to 2D can be adopted.
That is, FIG. 2B shows an example in which a pair of permanent magnets 11a and 11b are added in a row in the longitudinal direction of the main pipe 10, and FIG. 2C shows a pair of permanent magnets 11c and 11d added in the radial direction of the main pipe 10. Fig. 2 (d) shows an example of adding one-fourths apart and Fig. 2 (c)
This is an example in which permanent magnets 11a and 11b and 11c and 11d shown in FIG.

Further, as shown in FIGS. 2 (b) and 2 (d),
When a plurality of permanent magnets are arranged in the longitudinal direction of the pipe, the arrangement order of the magnetic poles of the permanent magnets may be changed. That is, a pair of permanent magnets 11a and 11b are arranged in parallel.
As shown in FIG. 3B, the magnetic field processing device 11 shown in FIG.
Table 1 shows the arrangement of the magnetic poles of the permanent magnets when four main tubes 10 are connected in the longitudinal direction. Similarly, two pairs of permanent magnets
11a and 11b are equally spaced in the circumferential direction of the main pipe,
As shown in FIG. 3B, Table 2 shows the arrangement of the magnetic poles of the permanent magnets when four magnetic field processing apparatuses 11 shown in FIG. 3C are connected in the longitudinal direction of the main pipe 10, as shown in FIG.

[0013]

[Table 1]

[0014]

[Table 2]

As described above, when a magnetic field is applied to the combustion air guided to the incinerator, the reactivity of the combustion air changes. As a result, combustion is more advantageous than in the conventional example under the same operating conditions. Will be promoted. In other words, at the same residence time and temperature, the combustion is promoted by the application of the present invention, and the waste can be incinerated under complete combustion and stable combustion. As a result, harmful substances can be suppressed.

The strength of the magnetic field applied to the combustion air is preferably about 200 to 2000 Gauss in order to ensure that the magnetic field is applied to the combustion air to enhance the effect of suppressing the generation of harmful substances. Therefore, as a permanent magnet, pipe diameter 50
It is preferable to use a ferrite magnet when the diameter is about mm or less, and to use a rare-earth magnet for piping having a diameter exceeding that. Further, in order to allow the magnetic force lines to pass through the combustion air pipe, it is preferable to use a pipe made of a plastic material or stainless steel.

In the example shown in FIG. 1, the magnetic field processing device 11 does not need to specify the installation position if it is between the blower 13 and the tip of the pipe extending below the grate of each stoker. A magnetic field must be applied to the combustion air flowing through 8a. Of course, it is also possible to provide the magnetic field processing device 11 in each of the pipes 7a, 8a and 9a of each stalker.

The type of the incinerator need not be limited to the stoker type shown in FIG. 1, but can be applied to a fluidized bed type or a rotary furnace type incinerator. By applying a magnetic field to the air, the desired effect can be obtained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the incinerator shown in FIG.
Adjust the atmosphere to 1.5 to reduce plastic waste to 4 t / h
In the incineration process, a magnetic field (magnetic field strength: 800 Gauss) was applied to the main pipe of the pipe that led air to each stoker. For comparison, an incineration treatment without applying a magnetic field was performed under the same conditions.

In each treatment, the concentration of harmful substances in the exhaust gas stack was measured by a CO concentration meter by an infrared absorption method and a hydrocarbon concentration meter by an infrared absorption method. As a result, while the concentration of harmful substances in the operation without applying the magnetic field was HC concentration: 300 ppm and the concentration of CO: 350 ppm, the concentration of harmful substances in the operation in which the magnetic field was applied to the combustion air pipe was HC Concentration: 270 ppm and CO concentration: 31
It became 5 ppm, and the generation of harmful substances was suppressed. In addition,
The amount of dioxin generated was evaluated based on the CO concentration.
This is because under the condition that the generation of dioxin is small, the generation of dioxin is also small.

[0021]

According to the present invention, the generation of harmful substances due to combustion is suppressed by simple means which can be applied to existing facilities at low cost, and the generation of harmful substances is not restricted by the conventional restrictions. The amount can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an incinerator to which the present invention is applied.

FIG. 2 is a diagram showing installation of a magnetic field processing apparatus on a pipe.

FIG. 3 is a diagram showing an arrangement of permanent magnets in the magnetic field processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waste collection vehicle 2 Waste 3 Waste pit 4 Crane 5 Input hopper 6 Feeder 7 Dry stoker 8 Burning stoker 9 Post-burning stoker 7a, 8a, 9a Piping 10 Main pipe 11 Magnetic field treatment device 11a to 11d Permanent magnet

Claims (1)

[Claims] When supplying combustion air to waste in an incinerator and burning and burning the waste, the combustion air is introduced into the waste in the incinerator. A method for incinerating waste in which generation of harmful substances is suppressed by applying a magnetic field.