JP2000179815A - Method for supplying auxiliary fuel in incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for supplying auxiliary fuel in an incinerator capable of decreasing a cost of a maintenance of an oil gun and reducing a supply amount of the fuel. SOLUTION: In the incinerator for incinerating a material to be incinerated of a low calorific value necessary for an auxiliary fuel, entirety or part of the fuel necessary for incinerating is mixed within a material-to-be-incinerated supply line 14, and supplied into the furnace. Thus, an oil gun 16 for supplying the oil can be reduced or discarded. Since a blowing amount of a high pressure air from the gun 16 is reduced, a temperature drop in the furnace is eliminated, and a supply amount of the fuel can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying auxiliary fuel in an incinerator for incinerating incinerators of low calorific value requiring auxiliary fuel.

[0002]

2. Description of the Related Art When incinerating high-moisture content incinerators such as sewage sludge in a fluidized bed incinerator or the like, it is necessary to supply auxiliary fuel such as heavy oil into the incinerator. Therefore, conventionally, as shown in FIG. 3, a number of oil guns 2 are radially arranged inside the fluidized bed 1 and auxiliary fuel such as heavy oil is injected by high-pressure air.

However, these oil guns 2 have a temperature of about 700.degree.
And is easily consumed by the fluidized medium in the fluidized bed incinerator, and the nozzle for supplying the auxiliary fuel may be clogged and blocked by the fluidized medium. For this reason, it is necessary to stop the operation of the equipment and clean or replace the equipment each time, and maintenance of many oil guns 2 requires a lot of expense. Further, since the high-pressure air supplied to the oil gun 2 is at room temperature, there is a problem that the inside of the furnace is cooled, and the supply amount of the auxiliary fuel needs to be increased accordingly.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and provides an auxiliary fuel supply method for an incinerator which can reduce the maintenance cost of the oil gun and reduce the supply amount of the auxiliary fuel. It was made to provide.

[0005]

According to a first aspect of the present invention, there is provided an incinerator in which a part of auxiliary fuel required for incineration is mixed into an incineration material supply line and supplied to the furnace. The remainder is supplied from the oil gun into the furnace. In order to solve the same problem, the invention of claim 2 is characterized in that all of the auxiliary fuel necessary for incineration is mixed into an incinerated material supply line and supplied to the furnace.

According to the present invention, a part or all of the auxiliary fuel required for incineration is mixed into the incineration material supply line and supplied to the furnace. Can be reduced. Therefore, the cost of maintenance of the oil gun can be reduced. In addition, since the amount of high-pressure air required for injecting auxiliary fuel from the oil gun can be reduced, a temperature drop in the furnace due to high-temperature air at normal temperature can be prevented, and the supply amount of auxiliary fuel can be reduced. Hereinafter, preferred embodiments of the present invention will be described.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In FIG. 1, reference numeral 10 denotes a furnace body of a fluidized bed incinerator, which is fluidized by flowing air blown from a flowing air supply nozzle 11 installed at a lower portion thereof. The medium is caused to flow to form a fluidized bed 12. The incinerated material has a high water content and a low calorific value, such as sewage sludge. The incinerated material is put into the free board 15 of the furnace body 10 from the incinerated material supply line 14 by the high-pressure pump 13 and incinerated.

In this embodiment, the oil gun 16 is installed in the fluidized bed 12, but the number thereof is one to three, which is far smaller than in the past. Fuel oil, which is an auxiliary fuel, is supplied to these oil guns 16 and is injected into the fluidized bed 12 by high-pressure air as in the related art. However, as shown in the figure, some of the auxiliary fuel required for incineration is
4 and supplied into the furnace, the oil gun 16
Reducing the number of fuels does not change the total amount of auxiliary fuel.

As a method of supplying the auxiliary fuel to the incineration material supply line 14, there are a method of supplying the fuel in a pipe and a method of supplying the fuel to a stage preceding the high pressure pump 13. When the fuel is supplied into the pipe, if the fuel is supplied to the inner wall surface of the pipe, the auxiliary fuel acts as a lubricant, and the friction in the pipe of the incineration material supply line 14 is reduced, so that the power of the high-pressure pump 13 can be reduced. However, since the incinerated material is thrown into the furnace with a large amount of auxiliary fuel attached to the surface, the auxiliary fuel burns instantaneously in the furnace, and the temperature difference between the fluidized bed 12 and the free board 15 increases. Combustion may become unstable. Therefore, when the mixing ratio of the auxiliary fuel to the incinerated material is high, it is preferable to supply the auxiliary fuel to the center of the pipe.

On the other hand, the method of supplying the fuel to the stage before the high-pressure pump 13 has an advantage that it can be employed regardless of the mixing ratio of the auxiliary fuel. However, when the water content and the calorific value of the incinerated material fluctuate greatly, the temperature lag in the furnace becomes unstable due to the time lag while traveling in the incinerated material supply line 14. It is preferable to adopt a method of supplying the water to the container.

The supply rate of the auxiliary fuel to the incinerated material is about 2 to 3% when the water content of the incinerated material is about 80%.
With this degree, there is no problem even if any of the above methods is adopted. However, when the supplementary fuel supply rate exceeds 5%,
In the method of supplying to the inner wall surface of the pipe, burning occurs and combustion becomes unstable. In such a case, if the incinerated material is charged into the fluidized bed 12, the burning can be suppressed.

As described above, if a part of the auxiliary fuel required for incineration is mixed into the incinerated material supply line 14 and supplied into the furnace, and the remainder is supplied from the oil gun 16 into the furnace,
Since the number of oil guns 16 can be reduced as compared with the conventional art, the cost of maintenance can be reduced, and the operation stop time for maintenance and replacement can be reduced. Further, by mixing a part of the auxiliary fuel into the incineration material supply line 14, the power of the high-pressure pump 13 can be reduced. Further, since the amount of high-pressure air used for the oil gun 16 is also reduced, the compressor can be downsized, and a decrease in the furnace temperature due to the blowing of high-pressure air is suppressed, so that the amount of auxiliary fuel used is reduced.

(Second Embodiment) Although a small number of oil guns are used in the above-described first embodiment, in the second embodiment shown in FIG. 2, all of the auxiliary fuel required for incineration is supplied to the incineration material supply line. 14 and fed into the furnace, eliminating the oil gun. According to this embodiment, the cost for maintenance of the oil gun and the operation stoppage time for replacement can be reduced to zero. Also, high-pressure air for the oil gun is not required, and a compressor for the oil gun can be eliminated, and there is no decrease in furnace temperature due to blowing of high-pressure air.

In the second embodiment, the control of the supply amount of the auxiliary fuel is relatively simple, and the furnace temperature (basically, the temperature of the fluidized bed 12 and, in some cases, the temperature of the free board 15) is kept constant. What is necessary is just to control the supply amount of the auxiliary fuel to the incineration material supply line 14 so as to be as follows. On the other hand, when the oil gun 16 is used together as in the first embodiment, the supply amount of the auxiliary fuel to the incinerated material supply line 14 and the oil gun 16 is simultaneously controlled by a single controller,
A method is required in which the supply amount to the incineration supply line 14 is fixed and the supply amount of the auxiliary fuel is controlled only by the oil gun 16. The method of controlling only with the oil gun 16 has an advantage that it can immediately respond to a change in temperature of the fluidized bed 12. Next, examples of the present invention will be described.

[0015]

EXAMPLE As shown in FIG. 3, one oil gun 16 was installed in the fluidized bed 12, and heavy oil as auxiliary fuel was supplied to both the incinerated material supply line 14 and the oil gun 16. However, the amount of auxiliary fuel supplied to the incineration material supply line 14 was 2% or less of the incineration material supply weight, and was a constant value that was half of the required amount at the time of average properties. Therefore, the remaining 50% was supplied from the oil gun 16 into the furnace while controlling the flow rate according to the property fluctuation of the incinerated material.

However, the upper limit of the amount of auxiliary fuel supplied to the oil gun 16 is also 30 L / hr. If the flow rate is exceeded, the auxiliary fuel will not be uniformly dispersed in the furnace, resulting in incomplete combustion. For this reason, it may be better to add the oil gun 16 depending on the properties of the incinerated material. Auxiliary fuel was supplied to the incineration material supply line 14 from four locations on the inner wall of the pipe. In this way, the auxiliary fuel is uniformly dispersed over the entire surface of the incinerated material, and an excellent lubricating effect can be obtained.

The dewatered sewage sludge (water content: 80%) was incinerated at a rate of 2 tons per hour by the fluidized bed incinerator shown in FIG.
The required amount of the auxiliary fuel is 58 L / hr, half of which is supplied to the incineration material supply line 14, and the remainder is controlled by the oil gun while controlling the flow rate so that the temperature of the fluidized bed 12 is kept constant at 680 to 900 ° C. 16 and sprayed into the fluidized bed 12. FIG.
As compared with the conventional method shown in FIG. 1, the power of the high-pressure pump 13 in the incineration material supply line 14 is reduced by about 10%, and the amount of high-pressure air blown from the oil gun 16 is reduced by half. It decreased by 10%.

[0018]

As described above, according to the present invention, the cost for the maintenance of the oil gun can be reduced by reducing or eliminating the oil gun. Also, the amount of high-pressure air required to inject auxiliary fuel from the oil gun can be reduced,
A temperature drop in the furnace due to high temperature air at normal temperature is prevented, and the supply amount of auxiliary fuel can be reduced. Further, there are many advantages such as the auxiliary fuel supplied to the incineration material supply line acting as a lubricant, and the power of the high pressure pump in the incineration material supply line can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing an embodiment.

FIG. 4 is a sectional view showing a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 fluidized bed, 2 oil gun, 10 body of fluidized bed incinerator, 11 nozzle for fluidized air supply, 12 fluidized bed, 1
3 High pressure pump, 14 Incineration material supply line, 15 Free board, 16 Oil gun

Claims (2)

[Claims] An auxiliary fuel in an incinerator characterized in that a part of auxiliary fuel required for incineration is mixed into an incineration material supply line and supplied into the furnace, and the remainder is supplied from an oil gun into the furnace. Supply method. 2. A method for supplying auxiliary fuel in an incinerator, wherein all of the auxiliary fuel required for incineration is mixed into an incinerated material supply line and supplied into the furnace.