JP2000008057A - Solid fuel and is production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a solid fuel having a high calorific value with a low content of chlorine by pulverizing wastes of plastics, carrying out a dechlorinating treatment, on the other hand, pulverizing combustible wastes freed of plastics, conducting a dechlorinating treatment and mixing both the resultant wastes. SOLUTION: This solid fuel is obtained by pulverizing wastes of plastics, heating the pulverized wastes at 200-400 deg.C preferably in a deoxygenated atmosphere, thereby carrying out a dechlorinating treatment, on the other hand, pulverizing combustible wastes freed of plastics, then preferably conducting a treatment with warm water, thereby performing a dechlorinating treatment and mixing both the dechlorinated wastes of the plastics with the dechlorinated combustible wastes. The resultant solid fuel preferably has >=3,500 kcal/kg calorific value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for efficiently removing chlorine contained in a plastic waste and a combustible waste from which plastics have been removed by separately desalting the same, and using these as raw materials to contain chlorine. The present invention relates to a method for producing a solid fuel having a small amount and a high calorific value, and to the solid fuel.

[0002]

2. Description of the Related Art Conventionally, combustible waste has been incinerated for the purpose of volume reduction, and incinerated ash generated by incineration has been disposed of by landfill. However, in recent years, it has been clarified that highly toxic dioxins are generated during waste incineration, which limits the operation of incineration facilities that emit large amounts of dioxins.
It has become mandatory to suppress the generation of dioxins by performing continuous operation while maintaining the incineration temperature at a high temperature of 850 ° C. or higher, and rapidly cooling the exhaust gas temperature to 300 ° C. or lower.

[0003] In order to stably operate the incinerator at such high temperatures as described above, it is necessary to continuously keep dust as homogeneous as possible. They vary widely and vary greatly depending on their transport and intermediate processing methods. Therefore, it is necessary to consider a wider area of garbage disposal including garbage transportation and disposal methods, which involves a very difficult problem.

As a method for obtaining relatively homogeneous refuse fuel without depending on such a wide range of refuse treatment, refuse solid fuel conversion technology has attracted attention. Garbage solid fuel is obtained by using a combustible waste as a raw material, pulverizing the combustible waste to remove incombustible substances such as metal, and drying and molding. By such a treatment, the combustible waste is homogenized to become a solid fuel capable of stable combustion, and since a metal serving as a catalyst at the time of dioxin generation is removed, generation of dioxin is suppressed. Furthermore, since the lime-based additive added as required fixes the chlorine content during combustion, dioxin production can be further suppressed.

[0005] However, the conventional refuse solid fuel is effective in suppressing the generation of dioxins, but has a problem in that a sufficient effect of suppressing generation of corrosive gas such as hydrogen chloride cannot be obtained. Since corrosive gas such as hydrogen chloride corrodes not only incineration equipment but also exhaust gas dust collection equipment, it is necessary to suppress generation of dioxins and eliminate as much as possible. Therefore, various methods have been proposed for adding a desalting step to the refuse solid fuel production process to produce refuse solid fuel having a low chlorine content. However, both methods have problems such as high cost and difficulty in optimizing processing conditions. Therefore, there is a demand for a method of efficiently removing a chlorine source to produce a refuse solid fuel having a small amount of chlorine.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problem in the conventional refuse-to-fuel processing, and desalination of plastics in the conversion of combustible waste including plastics waste to solid fuel. Separation of treatment and desalination of other combustible wastes, and by performing desalination separately, efficiently remove chlorides contained in these and produce garbage solid fuel with low chlorine content The present invention provides a method and its solid waste fuel.

[0007]

That is, the present invention provides:
(1) While plastic waste is pulverized and desalted, flammable waste from which plastics are removed is crushed and desalinated, and the desalted plastic waste and flammable waste are removed. The present invention relates to a method for producing a solid fuel, characterized in that a solid fuel is mixed with a solid fuel.
As an example, the production method of the present invention is as follows.
In the production method, the combustible waste from which the plastics have been removed is pulverized, and the combustible waste from which the plastics have been removed is pulverized, and then desalted by treating with hot water. is there. Further, the present invention relates to (3)
It relates to a solid fuel obtained by the method (1) and having a chlorine content of 2000 ppm or less and a calorific value of 3500 kcal / kg or more.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The production method of the present invention is a method for pulverizing plastic waste and desalinating it, while pulverizing combustible waste from which plastics have been removed and desalinating the plastic waste, and desalting these plastic wastes. And a combustible waste to obtain a solid fuel.

In the present invention, the plastic waste is
Discarded plastics such as polyvinyl chloride, polyethylene, polypropylene and styrene. In addition, combustible waste other than plastics includes kitchen waste,
It is waste mainly composed of wood, paper, or fiber.
It is waste generally called combustible waste. The plastic waste and the combustible waste other than the plastic waste may be separated and collected in advance, or may be separated and collected after collection.

According to the production method of the present invention, plastic waste and combustible waste other than the plastic waste are individually desalted. Combustible waste excluding plastics can easily elute and remove chlorine content by hot water treatment,
Since plastics are insoluble in water, such desalting treatment cannot be performed. In addition, if plastics and paper or fibers are mixed and combustible waste is mixed and treated at a high temperature at which the plastics are melted, the papers and fibers are burned and cannot be converted to fuel. The present invention efficiently removes chlorine by subjecting these to individual desalting.

(I) Desalting of Plastic Waste The method of desalting plastic waste is not limited. Any method may be used as long as it can be desalted efficiently. As an example, first, plastics waste is pulverized to about 20 mm or less, and then chlorine is removed by heating to 200 ° C. or more and 400 ° C. or less in a deoxygenated atmosphere such as a vacuum or an inert gas. There is a way. The desalted plastic waste thus obtained has a low chlorine content,
It is suitable as a raw material for the high calorific value solid fuel of the present invention.

(II) Flammable waste excluding desalinated plastics is mainly composed of kitchen garbage and paper, as described above. High in water-soluble chloride. Therefore, the chlorine content can be relatively easily removed by the water washing process. Specifically, first, pulverization is performed to increase the efficiency of removing chlorine. As the particle size of the pulverized product is smaller, the contact area between the pulverized product and water increases, so that the effect of removing chlorine is increased, but the pulverization cost is increased. Therefore, the particle size of the pulverized product is suitably about 1 to 30 mm, and preferably about 1 to 20 mm. The temperature of the treated water is suitably 25 ° C. or higher, preferably 30 ° C. or higher. Further, the processing time is suitably 2 minutes or more, and preferably 3 minutes or more. The method of water treatment may be washing with water like a shower or dispersion in water.

After the above-mentioned water treatment, the pulverized material is recovered and dehydrated. The recovery and dehydration operations are not particularly limited. It is preferable to use a centrifuge, a filter press or the like. The cake obtained by dehydration preferably has a water content of about 70% by weight or less in consideration of the next drying step.

Next, the dehydrated cake is dried. As a drying means, mixing additives with exothermic reaction such as quicklime,
It is good to utilize the exothermic reaction. Further, drying may be performed using external heat of a boiler or the like. In the case of drying by external heat, before or after drying, lime powder such as quicklime or slaked lime, coal ash, cement, or gypsum are mixed, and drying efficiency is improved by using their water absorption. In both cases, the effect as a molding aid can be utilized.

(III) Mixing / Solidification Plastic waste and combustible waste , each of which has been desalted, are mixed to obtain a solid fuel. As a mixing method,
The previously desalted plastics waste is pulverized if necessary and mixed with the combustible waste dewatered cake. This mixing ratio can be appropriately determined according to the desired amount of heat. Generally, about 10,000 kcal / k for desalted plastics
g of calorific value and about 400 for desalted combustible waste.
A calorie of about 0 kcal / kg is obtained.

The shape of the solid fuel comprising the above mixture may be a powder or a compact. The compacting is carried out in order to obtain a shape suitable for transportation and combustion equipment, but it is not necessary to carry out the compacting when the shape of the powder or granules is preferable during combustion. Rather, pulverize to the required particle size. In the case of molding, the amount of additives such as lime powder is adjusted according to the molding machine to be used, and molding is performed so as to obtain a desired shape, size, hardness and the like.
As the molding machine, a known molding machine such as an extrusion molding machine or a roll press molding machine can be used.

The refuse solid fuel of the present invention thus obtained has a low chlorine content, so that the generation of hydrogen chloride is greatly suppressed, the field of use as a fuel is widened, and the amount of use thereof is also increased. Can be. Therefore, it also contributes to solving the problem of refuse disposal for which it is difficult to secure landfill sites.

[0018]

Next, the present invention will be specifically described by way of examples. Note that these do not limit the scope of the present invention.

Examples 1-3 Approximately 10 kg of waste plastics derived from general wastes were pulverized to less than 20 mm using a twin-screw crusher, and the pulverized materials were placed in a closed container, and the inside of the container was replaced with nitrogen gas. And 37
The mixture was heated to about 0 ° C. to dissociate the chlorine content in the plastic, and the generated hydrogen chloride gas was exhausted to recover about 9.2 kg of plastic waste. This desalted plastic waste was ground to 5 mm or less. Table 1 shows the chlorine content and the calorific value of the desalted plastic waste in comparison with those before the treatment. On the other hand, flammable waste 1 shown in Table 2
0 kg was pulverized to 20 mm or less using a twin-screw crusher, and the pulverized product was dispersed in water at 30 ° C. and stirred for 3 minutes. Thereafter, the cake was dehydrated by a centrifugal separator, and the obtained cake was laid out on a filter plate covered with a resin filter cloth, washed by spraying 100 kg of water, and then transferred to a compression press equipped with a filter cloth to obtain a water content. It was dehydrated to 70% by weight. Further, the dehydrated cake was dried with a sludge dryer until the water content became 5% by weight to obtain a powdery desalted waste. Table 2 shows the chlorine content and calorific value of this desalted combustible waste. The desalted plastic waste and the desalted combustible waste were mixed at the ratio shown in Table 3 to obtain a powdered solid fuel. Table 3 shows the chlorine content and the calorific value of each solid fuel.

Comparative Example Approximately 10 kg of the plastic waste shown in Table 1 was dry-primarily ground using a twin-screw crusher, and further dry-secondarily crushed to 5 mm or less using a rotary crusher that combines both impact and shearing. Table 1
Was crushed to 20 mm or less using a twin-screw crusher. These pulverized materials were mixed at a ratio shown in Table 3 without desalting to obtain a powdered solid fuel. This powdered solid fuel was molded using an extrusion molding machine to obtain a cylindrical refuse solid fuel (diameter 15 mm, length 30 mm). Table 3 shows the chlorine content and the calorific value of this refuse solid fuel.

As shown in Examples 1 to 3 in Table 3, the solid fuel of the present invention in which plastic waste and flammable waste were separately desalted was compared with a comparative example in which no desalination treatment was performed. The amount is very small and the calorific value is high. Further, it can be seen that the heat value can be adjusted by changing the mixing ratio.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

As described above, according to the method for producing a solid fuel of the present invention, a solid fuel having a very low chlorine content and a high calorific value can be produced. Further, the calorific value of the solid fuel can be adjusted.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazushi Izumi 2-4-2 Daisaku, Sakura-shi, Chiba F-term (reference) 4H015 AA01 AA17 AB01 BA08 BA12 BB03 BB10 BB01

Claims (3)

[Claims] Claims: 1. Plastics wastes are pulverized and desalted, while plastics-removed combustible wastes are pulverized and desalted. A method for producing a solid fuel, comprising mixing with a waste material a solid fuel. 2. A plastic waste is pulverized and desalinated by heating to 200 to 400 ° C. in a deoxygenated atmosphere, while a combustible waste from which plastics have been removed is pulverized and then treated with hot water. The production method according to claim 1, wherein the solid fuel is desalted, dehydrated, and mixed to obtain a solid fuel. 3. A chlorine content of 20 obtained by the method of claim 1.
Solid fuel with a calorific value of 3500 kcal / kg or more, with a value of 00 ppm or less.