Gas: heating and illuminating – Processes – Fuel mixtures
Reexamination Certificate
2001-02-27
2004-06-08
Johnson, Jerry D. (Department: 1764)
Gas: heating and illuminating
Processes
Fuel mixtures
C048S077000, C048S089000, C048S101000, C048S111000, C048S119000, C048S123000, C048S209000, C048S210000, C201S001000, C201S015000, C201S025000, C201S027000, C201S029000, C201S037000, C422S165000, C422S184100, C422S186220, C422S186220, C422S232000, C422S234000, C422S235000, C422S105000, C422S107000, C422S108000, C422S109000, C422S110000, C422S111000, C422S116000
Reexamination Certificate
active
06746497
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a waste incineration disposal method.
BACKGROUND ART
In recent years, it has been pointed out that dioxins are generated during incineration disposal of a waste. In many cases, the waste contains chlorine. Therefore, when the waste is combusted at a temperature of 250 to 350° C., chlorine liberated from the waste, and hydrocarbon generated by incomplete combustion of resins react with each other using a catalyst of a heavy metal contained in the waste, and dioxins are generated.
In order to prevent dioxins emission by the incineration disposal of the waste, it is said to be effective to retain the waste at 800° C. or more for two seconds or more, and completely thermally decompose the generated dioxins. However, even when the wastes such as miscellaneous living wastes, paper, and soft vinyl chloride are incinerated, it is difficult to stably keep the wastes at 800° C. or a higher temperature. Therefore, in order to prevent the dioxins emission, in general, the wastes are combusted together with other fuels such as a heavy oil, and thereby stably incinerated at 800° C. or more. In this case, since the other fuels have to be combusted together with the wastes through the entire incineration disposal process, a large amount of other fuels are required, and a running cost increase cannot be avoided.
Additionally, the present applicant has proposed an apparatus disclosed in Japanese Patent Application Laid-Open No. 135280/1990 as an incineration disposal apparatus of wastes such as a waste tire.
The apparatus disclosed in the above publication is constituted of a fully closed gasification furnace, and a combustion furnace connected to the gasification furnace via a gas passage a part of the waste is combusted in the gasification furnace, and a combustible gas generated by dry distillation of the other part of the waste with the combustion heat is introduced into the combustion furnace to completely combusted the waste. Details of incineration disposal of the waste by the apparatus will next be described.
During the incineration disposal of the waste by the apparatus, first the waste contained beforehand in the fully closed gasification furnace is ignited, a part of the waste is combusted, and the other part thereof is dry-distilled by the combustion heat. Moreover, the combustible gas generated by the dry distillation is introduced into the combustion furnace disposed outside the gasification furnace via the gas passage.
Subsequently, a combustion flame is supplied to the introduced combustible gas to ignite the gas, thereby starting combustion of the combustible gas.
Next, when the dry distillation progresses and the combustible gas is stably generated, an amount of generated combustible gas gradually increases, and a combustion temperature of the combustible gas detected as a temperature T
2
in the combustion furnace gradually rises as shown in FIG.
3
. In this case, the temperature T
2
in the combustion furnace reaches a temperature T
2a
at which the combustible gas can spontaneously and stably continue the combustion by its own combustion heat, and the supply of the combustion flame is then stopped.
Subsequently, oxygen necessary for complete combustion of the combustible gas is supplied to the combustion furnace in accordance with the amount of the combustible gas introduced into the combustion furnace. Additionally, while the combustible gas is completely combusted, the temperature T
2
in the combustion furnace is detected as the combustion temperature of the combustible gas, an amount of oxygen supplied to the gasification furnace is controlled in accordance with a change of temperature T
2
, and the amount of the combustible gas generated by the dry distillation is adjusted. In the apparatus, the temperature T
2
in the combustion furnace can be maintained in this manner to be substantially constant at a temperature T
2b
higher than a temperature T
2a
at which the combustible gas spontaneously and stably continues the combustion.
In the apparatus, when the dry distillation further progresses, a portion of the waste able to be dry-distilled in the gasification furnace is reduced. Even when the amount of oxygen supplied to the gasification furnace is increased, a sufficient amount of combustible gas for maintaining the temperature T
2
in the combustion furnace to be substantially constant at the temperature T
2b
cannot be generated Then, the temperature T
2
in the combustion furnace gradually drops, the dry distillation and combustion of the waste in the gasification furnace are finished and the waste is ashed. Additionally, a temperature in the gasification furnace is shown as T
1
in FIG.
3
.
As a result, according to the apparatus, the dry distillation of the waste and the complete combustion of the combustible gas can stably be performed, and in a stage in which the combustible gas spontaneously and stably, continues the combustion, the temperature in the combustion furnace can be maintained to be substantially constant at a preset or higher temperature.
Here, when the apparatus disclosed in the above publication is used in the incineration disposal of the waste, the waste is regulated so as to generate the combustible gas having heat amount for setting a combustion temperature at which dioxins can thermally be decomposed, for example, at 800° C. or more. Then, in the stage in which the combustible gas spontaneously and stably continues the combustion, the temperature in the combustion furnace can be maintained to be substantially constant at 800° C. or more. Therefore, to keep the temperature in the combustion furnace at 800° C. or more, it is unnecessary to combusted other fuels such as a heavy oil, and the dioxins emission can be prevented at a low cost.
However, during the aforementioned waste incineration disposal, in the stage in which the combustible gas spontaneously and stably continues the combustion after the start of the waste dry distillation, and in the stage in which the portion of the waste able to be dry-distilled in the gasification furnace is reduced and the waste is ashed after the stage of the spontaneous and stable continuation of the combustion of the combustible gas, the temperature in the combustion furnace does not reach 800° C. and there is a disadvantage that dioxins are emitted.
DISCLOSURE OF THE INVENTION
To solve the aforementioned disadvantage, an object of the present invention is to provide a waste incineration disposal method which can prevent dioxins emission and reduce running costs.
To achieve the aforementioned object, the waste incineration disposal method of the present invention comprises steps of: combusting a part of a waste contained in a gasification furnace, and dry-distilling the other part of the waste by a combustion heat; and introducing a combustible gas generated by the dry distillation into a combustion furnace to combusted the combustible gas. When the combustible gas is combusted in the combustion furnace, oxygen required for the combustion is supplied to the combustion furnace in accordance with an amount of the combustible gas introduced into the combustion furnace to combusted the combustible gas, an amount of oxygen supplied to the gasification furnace is controlled in accordance with a temperature change in the combustion furnace by the combustion of the combustible gas in the combustion furnace, the amount of the combustible gas generated by the dry distillation is adjusted, and the temperature in the combustion furnace is maintained to be substantially constant at a first preset temperature or more. In the waste incineration method, the waste regulated to generate the combustible gas having a heat amount for setting the temperature in the combustion furnace at the first preset temperature or more during the combustion is contained in the gasification furnace. Fuels other than the combustible gas are combusted in the combustion furnace prior to ignition of the waste. When the temperature in the combustion furnace reaches the first preset temperature o
Guss Paul A.
Johnson Jerry D.
Kinsei Sangyo Co., Ltd.
Ridley Basia
LandOfFree
Waste incineration disposal method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Waste incineration disposal method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Waste incineration disposal method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3301705