JP2007262283A - Waste-containing fuel, and its preparing method and using method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide waste-containing fuel which is prepared by converting spent white clays into a material easy in handling, and is usable as a good alternative fuel for cement firing; and to provide its preparing method and using method. <P>SOLUTION: The waste-containing fuel is prepared by kneading one or two selected from among spent white clays, an inorganic powder, pulverized wood waste and a waste plastic granule. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention makes it easy to handle waste clays produced by deodorization treatment and decoloration treatment of mineral oil and vegetable oil, and is a waste-containing fuel that is a good alternative fuel for cement firing, a method for producing the same, and a waste-containing fuel. Regarding usage.

Waste clay is generally used activated clay containing oil and fat (mineral oil and vegetable oil) generated by deodorizing and decolorizing mineral oil and vegetable oil with activated clay.
Normally, waste clay contains about 40% by weight of oil and fat and a small amount of water. Since the waste clay contains oil and fat, it has a calorific value of 12,500 MJ / kg (≈3000 kcal / kg) or more and can burn itself.
Further, any of the following (a), (b), and (c), in which the calorific value is adjusted to the same level as that of waste white clay, is naturally possible.
(A) A mixture of inorganic powders such as coal ash and incinerated ash, and about 20 to 50% by weight of waste oil and waste oil (including waste oil; hereinafter, waste oil includes waste oil) b) Incinerated ash containing unburned ash discharged from a dust collector, etc., and water and / or waste oil and fat mixed (c) Combustible sludge, or flammable sludge and waste oil and fat mixed Hereinafter, the above-mentioned waste clay, (a), (b) and (c) are collectively referred to as waste clay.

These waste clays are obtained by secondary impregnation of fats and oils into inorganic waste powder or organic waste powder having a particle size of 100 μm or less. These waste clays are very poor in fluidity compared to coal-based powdered fuels, and can be easily hardened simply by pressing them with your hands.
Such waste clay is mainly disposed of by incineration.
As a method for incinerating waste clay, a method using a rotary kiln or a vertical multi-stage incinerator is generally used. These methods of incinerating waste clays require a long time for incineration of waste clays.
Moreover, as a method for incinerating waste clay, a spray combustion method is also used in which waste clay and waste oil are mixed and made into a slurry to be sprayed at high pressure in an incinerator and atomized for incineration. In this spray combustion method, the waste clay is a fine particle, so when the waste clay burns, it is very easy to scatter with the combustion gas, and therefore sufficient measures are taken to remove dust (incineration ash) contained in the exhaust gas. There is a need. Since ash contained in the exhaust gas is mainly composed is SiO _2, the ash is effectively used as part replacement of the clay component in the cement kilns.

In cement firing furnaces, waste clay is introduced into the calcining furnace in the preheater using mechanical means and used as an alternative fuel. Considering that incinerated ash from waste clay can be effectively used as a raw material substitute, it can be said that waste clay is an excellent raw material for sentiment.
However, as described above, waste clay contains poor fat and fluidity because it contains fats and oils, and contains relatively large lumps. It is. For these reasons, a countermeasure for increasing the amount of waste clay used has been desired.

In addition, as a method for treating combustible materials, a method has been proposed in which waste oil or the like is kneaded with incinerated ash or large sawdust into a powder form, and the combustible material in the form of a powder is incinerated or used as an alternative fuel for fossil fuel. (For example, refer to Patent Document 1).
In this method, waste oil or waste liquid is used as a treatment agent using large sawdust, incinerated ash, and limestone powder, or one selected from powders of silicon oxide, aluminum oxide, calcium oxide, magnesium oxide, carbon, and the like. The waste oil and waste liquid are treated easily and safely by drying using a processing agent consisting of large sawdust. Then, as a final stage of the waste oil or waste liquid spill process, the processed product is dried and then incinerated.
Large sawdust has deodorizing and dehydrating effects, and limestone powder is alkaline. Therefore, large sawdust and limestone can neutralize waste oil that is often oxidized after use. Furthermore, the limestone powder absorbs harmful gases such as nitrogen dioxide generated when the treated product is incinerated, so that odor and smoke are considerably reduced.
Japanese Patent Laid-Open No. 08-103764

By the way, the waste clay used for the treatment of mineral oil and vegetable oil has poor fluidity depending on the properties of the treated oil and fat and the content of the oil and fat, and sometimes exhibits properties like clay. In addition, the waste clay can be easily hardened just by lightly pressing it by hand, and in some cases, many dumplings may be formed.
Also, waste oils, inorganic powders such as incineration ash and coal ash, and combustible powders such as large saw dust (kneaded material) were removed using a vibrating sieve etc. After that, it is difficult to handle as powder unless it is crushed. Furthermore, in order to treat the waste clay and the kneaded product as a powder, increasing the ratio of the inorganic powder to the oil and fat content, the calorific value of the waste clay and the kneaded product is reduced, Usefulness as an alternative fuel is impaired. A kneaded mixture of waste clay and flammable powder such as large sawdust has a lower calorific value and an increased amount of ash (inorganic powder) compared to a kneaded mixture of waste white clay and inorganic powder. However, depending on the properties of the combustible powder, the kneaded product may be difficult to handle.

  The present invention has been made in order to solve the above-mentioned problems, and makes it easy to handle waste clays, and also includes a waste-containing fuel as a good alternative fuel for cement firing, a method for producing the same, and waste It aims at providing the utilization method of contained fuel.

  As a result of intensive studies to solve the above problems, the present inventors do not cause major problems in cement production, and by selecting raw fuel with good fluidity, kneading including waste clay It has been found that the product can be easily handled and can be used as a good alternative fuel for cement firing, and the present invention has been completed.

  That is, the waste-containing fuel of the present invention is obtained by kneading one or two types of waste clay, inorganic powder, pulverized wood waste, and waste plastic powder. And

  In the waste-containing fuel of the present invention, the waste clay is waste clay, combustible sludge, a mixture of inorganic powder and 20% by weight or more and 50% by weight or less of waste oil and fat, incinerated ash containing unburned matter, It is preferable that it is 1 type, or 2 or more types selected from the group of the mixture of water and / or waste oil and fat, the mixture of combustible sludge and waste oil and fat.

  In the waste-containing fuel of the present invention, the inorganic powder is one or more selected from the group of incinerated ash, coal ash, limestone powder, cement raw material powder, cement, and crushed powder of concrete waste material Is preferred.

  The method for producing a waste-containing fuel of the present invention is a kneaded product obtained by kneading one or two types of waste clay, inorganic powder, wood chip pulverized material and waste plastic powder, The kneaded product is crushed and classified into coarse and fine particles, and the fine particles are used as a waste-containing fuel.

  The method for using the waste-containing fuel of the present invention is characterized in that the waste-containing fuel of the present invention is burned in a cement firing furnace.

  According to the waste-containing fuel of the present invention, it is formed by kneading any one or two kinds of waste clay, inorganic powder, pulverized wood waste, and waste plastic powder. It is uniform, easy to handle, and good as an alternative fuel for cement firing. Therefore, the waste-containing fuel of the present invention does not cause troubles in transportation, improves the combustibility, and can further increase the amount used in the cement firing furnace. As a result, the use of fossil fuels can be reduced. Moreover, it can contribute to reduction of environmental load.

The best mode of the waste-containing fuel of the present invention, the production method thereof, and the utilization method of the waste-containing fuel will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

  The waste-containing fuel of the present invention comprises waste clay, kneaded with one or two types of waste powder, inorganic powder, pulverized wood chips and waste plastic powder. It is a kneaded material (waste clay mixture).

  Most of the waste clay mixture that constitutes the waste-containing fuel of the present invention preferably has a major axis length of 5 mm or less, and a major axis length of 2 mm or less. Is more preferable. If the length of the major axis direction of most of the waste clay mixture in the present invention is 5 mm or less, the waste clay containing dumpling-shaped lump gradually reacts with oxygen from the surface and burns. In addition, since this waste clay mixture has a larger reaction area (area in contact with oxygen) than waste clay containing dumpling-like lumps, the fat and oil contained in the waste clay mixture is volatilized quickly. In addition, since the frequency of contact between the oil and fat and oxygen increases, the oil and fat can be burned in a short time. In addition, when the oils and fats are burned, the surrounding area where they burn is heated, so the wood scraps and waste plastic particles contained in the waste clay mixture are also burned efficiently in a short time. Can be made.

  Waste clay is (i) waste clay, (b) flammable sludge, (c) a mixture of inorganic powder and 20% to 50% waste oil and fat, and (d) incineration containing unburned matter. It is 1 type, or 2 or more types selected from the group of the mixture of ash, water, and / or waste oil and fat, and (e) the mixture of combustible sludge and waste oil and fat.

The inorganic powder is one or more selected from the group of incinerated ash, coal ash, limestone powder, cement raw material powder, cement, and crushed powder of concrete waste.
Among these inorganic powders, most of incineration ash and coal ash are made of powder, and coarse particles having a maximum length of about several millimeters in the major axis direction are slightly mixed.
Incineration ash and coal ash are made of an inorganic material that has a slight calorific value depending on the amount of unburned carbon and the like contained in the ash and coal ash, but has little calorific value.
Although the moisture content of incineration ash and coal ash is approximately 0% by weight at the generation stage, in some cases it is around 25% by weight for the purpose of suppressing dust generation during transportation to a cement factory. It has been adjusted.

  In the waste-containing fuel of the present invention, any one of waste white earth, inorganic powder, crushed wood waste, and waste plastic powder is used in order to ensure the calorific value and improve the ease of handling. The mixing ratio of the seeds or the two kinds is 55% to 80% by weight of the waste clay, 10% to 20% by weight of the inorganic powder, one of the pulverized wood chips and the waste plastic powder. It is preferable that the seeds or two kinds are 10% by weight to 25% by weight. The mixing ratio of the crushed wood waste and the waste plastic powder is 20% to 80% by weight of the crushed wood waste and 20% to 80% by weight of the waste plastic powder. Although it is preferable, one of the cases may be 0% by weight as in the embodiment in relation to the actual arrival amount ratio.

Moreover, since incinerated ash and coal ash have almost no calorific value, the calorific value of the waste clay mixture is reduced. Therefore, if the ratio of incinerated ash and coal ash is increased in the waste clay mixture, the amount of heat generated from the waste clay mixture decreases to a level where it cannot self-combust, and the waste clay mixture cannot be burned well. Therefore, the lower limit value of the calorific value of the waste clay mixture is determined, and the ratio of the incinerated ash and coal ash is determined so that the calorific value of the waste clay mixture becomes equal to or greater than the lower limit value. In the present invention, the lower limit value of the calorific value of the waste clay mixture is about 10,000 MJ / kg (≈2400 kcal / kg), preferably about 12,500 MJ / kg (≈3000 kcal / kg). This lower limit is determined on the assumption that the waste clay mixture is burned at a temperature of about 850 to 900 ° C. in a cement firing furnace.
In addition, the calorific value of the formulation example of the waste-containing fuel of the present invention shown in Table 1 is not less than the lower limit value of the calorific value.

The crushed wood waste is a needle-like powder having a maximum length in the major axis direction of 10 mm or less, which is separated by a sieve having an opening of about 7 mm after pulverizing the building waste material, and has a length in the major axis direction. Of about 2% or less, and about 10% by weight of those having a length in the major axis direction of 5.6 mm or more. In addition, the minor axis diameter is often 1/10 or less of the major axis length, and most is 1 mm or less.
Generally, when the pulverized product of wood chips contains about 80% by weight or more of a material having a length in the major axis direction of 2 mm or less, the residue is about 10 when separated by a sieve having a mesh size of 90 μm. It is said that it has a combustibility equivalent to that of the weight percent). Therefore, in the present invention, it is preferable that the pulverized material of wood waste contains about 80% by weight or more of a material having a length in the major axis direction of 2 mm or less. If such a pulverized product of wood waste is used, the waste clay mixture that forms the waste-containing fuel of the present invention exhibits good combustibility.

Further, the water content of the crushed wood chips is adjusted to a range of about 20 to 30% by weight by watering or the like in order to suppress dust generation when the building is demolished.
Further, when the crushed wood waste is kneaded with waste clay, the oil and fat contained in the waste clay slightly permeates itself, and the apparent amount of oil on the surface of the kneaded material decreases. Therefore, the kneaded material obtained by kneading the waste white clay and the pulverized wood waste becomes easy to handle.

For example, if the pulverized material of wood chips is large sawdust generated during sawing, the large sawdust itself is in the form of a granular material having a length in the major axis direction of about several millimeters. In addition, large sawdust disperses and absorbs the oil and fat contained in the waste clay, so it can be discarded simply by kneading the sawdust into the waste clay without kneading inorganic powder such as incinerated ash and coal ash. The clay mixture is easy to handle.
In this way, if the large sawdust generated at the time of sawing is used as a pulverized product of wood chips, there is no need to knead inorganic powder into waste clay, so there is no significant decrease in the amount of heat generation, and the amount of heat generation is relatively high. A waste clay mixture with good combustibility is obtained.

As waste plastic powder, waste plastic is crushed into thin pieces with a length of about 10 mm or less, waste mold resin, waste FRP (Fiber Reinforced Plastics), etc. Those having a length of several mm or less are used.
Waste plastic granules are significantly accelerated in decomposition at higher temperatures than coal, so they burn rapidly and the residue is about 10% when coal is separated by pulverized coal (with a sieve having an opening of 90 μm). It shows good combustibility equivalent to that of 1%).

Further, the water content of the waste plastic powder is almost 0% by weight because it hardly adds water or water.
Furthermore, even if the waste plastic powder is kneaded with the waste clay, the oil contained in the waste clay does not permeate itself, so the kneaded product of the waste clay and waste plastic powder is kneaded. Is inferior in handling to a kneaded product obtained by kneading waste white clay and a pulverized product of wood chips. However, since the calorific value of the waste plastic powder is higher than the calorific value of the crushed wood waste, it is excellent in increasing the calorific value of the waste clay mixture.

The pulverized wood waste and the waste plastic powder can also be produced by pulverization in a factory.
By the way, in order to make it easy to handle the waste clay mixture, the ratio of the incinerated ash and coal ash in the waste clay mixture is increased, so that the calorific value of the waste clay mixture is significantly less than 10,000 MJ / kg. In such a case, the combustibility of the waste clay mixture is greatly deteriorated. Therefore, the kneading ratio of incinerated ash and coal ash to waste white clay so as to achieve an improvement in the ease of handling of the intended waste white clay kneaded product and an increase in the calorific value of this waste white clay kneaded product Adjust. If it does in this way, the calorific value of a waste white clay kneaded material can also be improved, improving the ease of handling of a waste white clay kneaded material.

  The waste-containing fuel of the present invention is a waste white clay kneaded product obtained by kneading one or two types of waste white clay, inorganic powder, wood waste pulverized material, and waste plastic powder. Therefore, it is almost uniform, easy to handle, and good as an alternative fuel for cement firing. Therefore, the waste-containing fuel of the present invention does not cause any trouble in the transport aircraft, improves the combustibility, and can further increase the amount used in the cement firing furnace. As a result, since the use of fossil fuel can be reduced, it can contribute to reduction of environmental load.

Next, the manufacturing method of the waste containing fuel of this invention is demonstrated.
The method for producing a waste-containing fuel according to the present invention comprises kneading a waste clay, an inorganic powder, a pulverized product of wood chips, and a powdered product of waste plastics to form a kneaded product. The kneaded product is crushed and classified to obtain a waste-containing fuel.
That is, in the method for producing a waste-containing fuel of the present invention, first, (b) waste white clay, (b) combustible sludge, (c) inorganic powder and 20 to 50% by weight of waste oil and fat. It consists of one or more selected from the group consisting of a mixture, (d) a mixture of incinerated ash containing unburned matter and water and / or waste oil and fat, and (e) a mixture of combustible sludge and waste oil and fat. Prepare waste clay (preparation process of waste clay).

Next, waste clay, inorganic powder, pulverized wood chips, and one or two kinds of waste plastic powder are lightly mixed once, and this mixture is simply combined with a pug mill or paddle screw. A kneading apparatus is used to knead a relatively large amount continuously to obtain a waste white clay kneaded product (waste white clay kneading step).
According to a kneading apparatus such as a pug mill, the oil contained in the waste clay is dispersed in other inorganic powders, crushed wood scraps or waste plastic particles, thereby finely kneading the kneaded product. In addition to being able to form a fine granule, the dumpling-like lump mixed in the kneaded product can be crushed to a small extent.

  Next, after removing the coarse coarse particles from the waste clay mixture kneaded by a kneading device such as a pug mill with a simple sieve such as a grizzly bar, this is removed by a crushing device such as a rotary feather of a tiller. Crush (crushing process of waste clay mixture).

Next, the waste white clay kneaded material other than coarse particles classified by a sieve such as a grizzly bar is combined with the waste white clay kneaded material crushed by the crushing apparatus, and these are mixed using a vibrating sieve or the like. Classification is performed with a relatively fine particle size, and is classified into a coarse particle and a fine particle, and the fine particle is used as a waste-containing fuel (classification process of waste clay mixture).
The waste-containing fuel composed of the waste clay mixture is required to have a relatively small particle size in consideration of burning in a cement firing furnace. Accordingly, the length of the waste clay mixture is 5 mm or less, preferably 2 mm or less.

In addition, waste clay clay kneaded material consisting of coarse particles of a predetermined particle size or more classified with a vibrating sieve is returned to the kneading device or crushing device again, and gradually broken up to a predetermined particle size or less with these devices. To do.
By the way, since the maximum length in the major axis direction of the pulverized wood chips and waste plastic particles kneaded with the waste clay is about 10 mm, the waste clay mixture having a major axis length of 5 mm or more. In such a case, the waste clay mixture is made finer to such an extent that it passes through the vibrating sieve.
A waste-containing fuel made of a waste clay mixture having a predetermined particle size or less classified by a vibration sieve or the like in the classification step of the waste clay mixture is used as an alternative fuel for cement firing.

Here, for example, if the mesh opening of a sieve such as a grizzly bar is 5 mm, the ratio of the waste clay mixture remaining on the sieve will be about 22 to 25% by weight. When the thickness is 10 mm, the ratio of the waste clay mixture remaining on the sieve is about 15 to 18% by weight. Therefore, the particle size of the waste-containing fuel is 2 mm or less in the major axis length by adjusting the opening of the sieve in the classification process of the waste clay mixture just before being sent into the cement firing furnace. The ratio of the product is as fine as about 80% by weight or as coarse as about 50% by weight. Depending on the fineness of the particle size of the waste-containing fuel, the place where the combustion is completed by putting the waste-containing fuel into the calcining furnace of the cement firing facility is either in the calcining furnace and in the lowest cyclone or in the rotary kiln. Divided. When the sieve opening is 5 mm and when the sieve opening is 10 mm, the combustibility of the waste-containing fuel in the cement firing furnace is slightly different, and the sieve opening is 5 mm. The waste-containing fuel obtained is burned almost completely in the calciner and the lowermost cyclone.
However, if the sieve opening is reduced, clogging may occur depending on the sieve structure. In addition, the amount of waste clay mixture to be processed again by the kneading apparatus or the crushing apparatus increases, so that the processing capacity may be lowered. Therefore, not only is the combustibility of the waste clay mixture finally sent to the cement firing furnace, but it does not cause clogging of the sieve or other obstacles, and can also exhibit sufficient processing capacity in terms of equipment. Next, the opening of the sieve is determined.

  According to the method for producing a waste-containing fuel of the present invention, a waste-containing fuel comprising a waste white clay kneaded material that is substantially uniform and easy to handle and that is also good as an alternative fuel for cement firing can be easily obtained. Can be manufactured.

Next, a method for using the waste-containing fuel of the present invention will be described.
The method for using the waste-containing fuel of the present invention is a method for burning the waste-containing fuel of the present invention in a cement firing furnace.
That is, in the method for using the waste-containing fuel of the present invention, the waste-containing fuel composed of the waste clay mixture kneaded to a predetermined particle size or less by the method for producing the waste-containing fuel of the present invention is first transported. It is transported to a calcining furnace provided in the preheating part of the sentiment baking furnace through a machine and put in.
Next, because the waste-containing fuel charged into the calcining furnace burns in a short time in the calcining furnace and the lowermost cyclone of the suspension preheater, It burns almost completely.
The waste-containing fuel (waste clay mixture) that has become almost ash is collected by the lowermost cyclone and supplied to the kiln bottom of the cement kiln together with other raw materials.

The method for using the waste-containing fuel of the present invention is such that the waste-containing fuel of the present invention is burned in a cement firing furnace. Can be improved.

Claims (5)

  A waste-containing fuel obtained by kneading one or two kinds of waste clay, inorganic powder, pulverized wood waste, and waste plastic powder.   The waste clay is waste clay, combustible sludge, a mixture of inorganic powder and 20% by weight or more and 50% by weight or less of waste oil and fat, a mixture of incinerated ash containing unburned matter and water and / or waste oil and fat. The waste-containing fuel according to claim 1, wherein the fuel is one or more selected from the group consisting of flammable sludge and a mixture of waste oil and fat.   The inorganic powder is one or more selected from the group consisting of incinerated ash, coal ash, limestone powder, cement raw material powder, cement, and crushed powder of concrete waste material. The waste-containing fuel described.   Waste clay, inorganic powder, pulverized wood chips, and waste plastic powders are kneaded into one or two kinds to obtain a kneaded product, and the kneaded product is crushed, A method for producing a waste-containing fuel, characterized by classifying into fine particles and using the fine particles as waste-containing fuel. A method for using a waste-containing fuel, wherein the waste-containing fuel according to claim 1 is burned in a cement firing furnace.