JP4283495B2 - How to use ash-containing carbides - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for using ash-containing carbide, and more particularly, to a method for using waste-derived ash-containing carbide in a cement manufacturing process.
[0002]
[Prior art]
Conventionally, carbonized products obtained by carbonizing waste such as municipal waste, RDF, waste wood, waste paper, waste plastic, vegetable waste, food waste, sludge, food residue, livestock carcass, etc. are used as fuel for cement kilns. To be considered.
[0003]
Here, the upper limit of the amount of use as a substitute for cement fuel that is introduced together with the main fuel from the kiln of the cement kiln or from the nozzle provided with the main fuel burner is the amount of ash contained in the carbide, It is determined by the mass balance between the chlorine concentration in the cement and the chlorine concentration in the cement. That is, when the chlorine concentration in the cement reaches the limit value, it becomes impossible to use any more carbide containing chlorine in the cement manufacturing process.
[0004]
[Problems to be solved by the invention]
Waste such as municipal waste is dechlorinated, reduced in volume, and homogenized by carbonization. When the waste is carbonized, most of the organic chlorine content can be removed by thermal decomposition by carbonization. Furthermore, water-soluble inorganic chlorine such as sodium chloride and potassium chloride can be removed by washing with water. However, since these carbides contain a large amount of ash containing a hardly soluble chlorine-containing compound, there is a limit in using the carbides as a fuel replacement before the kiln in the cement manufacturing process. In other words, the ash contained in a large amount may cause the calorific value of the carbide to be insufficient for use as a fuel substitute, and the chlorine contained in the ash may be an obstacle to the use as a fuel substitute. Yes.
[0005]
Therefore, the present invention has been made in view of the problems in the above-described conventional technology, and includes municipal waste, RDF, waste wood, waste paper, waste plastic, vegetable waste, garbage, sludge, food residue, livestock. The purpose is to use as much as possible ash-containing carbides derived from waste such as carcasses in cement manufacturing processes.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a method for using ash-containing carbides, wherein the ash-containing carbides obtained by carbonizing waste are separated into low ash high carbides and high ash low carbides to obtain low ash high carbides. While using a high ash content low carbide as a raw material for cement manufacture, a portion of the chlorine content contained in the ash containing carbide is transferred to the raw material side for cement manufacture while using the cement manufacturing fuel. The water is removed by a chlorine bypass facility .
[0007]
And according to the present invention, by purifying the ash-containing carbide and replacing the high ash-low carbide with a clay substitute for cement raw material, a portion of the chlorine content contained in the ash-containing carbide is transferred to the cement raw material side. If this chlorine content is removed by the chlorine bypass system during cement production, it will be easier to design and control the raw material composition during cement production, and more ash-containing carbides will be used in the cement production process. can do.
[0008]
The ash-containing carbides, municipal waste, RDF, waste wood, waste paper, waste plastics, vegetable waste, garbage, sludge, food residue, it is a waste of carcasses such as livestock those carbonization. As a result, waste such as municipal waste can be used more in the cement manufacturing process, which can greatly contribute to waste disposal and effective use. In addition, it is preferable to use the flotation method as the fractionation method.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, a specific example of an embodiment of a method for using an ash-containing carbide according to the present invention will be described with reference to the drawings.
[0010]
In view of the above-mentioned problems, the present inventors have conducted intensive studies on using as much ash-containing carbides derived from wastes such as municipal waste as much as possible in the cement manufacturing process. By separating low ash high carbides and high ash low carbides, etc., using low ash high carbides as fuel for cement production and using high ash low carbides as raw materials for cement production, more ash-containing carbides can be cemented. It has been found that it can be used in the manufacturing process.
[0011]
An embodiment of a method for using ash-containing carbide according to the present invention will be described in detail with reference to FIG.
[0012]
First, wastes such as municipal waste, RDF, waste wood, waste paper, waste plastic, vegetable waste, garbage, sludge, food residue, livestock carcasses, etc., which are carbonized with a rotary kiln are used as carbides. The particle size of the carbide is adjusted and finely pulverized, and then mixed with water to form a slurry. In the carbonization of waste, a vertical furnace may be used. Further, the carbide may be pulverized by wet pulverization or dry pulverization. In order to increase the ash removal rate at the time of flotation in the subsequent process, the maximum particle size is adjusted to 0.5 mm or less, more preferably 0.1 mm or less. Further pulverization is not preferable because it leads to an increase in pulverization cost. The concentration of the carbide slurry is preferably 0.1 to 15% by weight, more preferably 0.5 to 5% by weight. If the concentration is higher, handling properties are worse, and the lower the concentration of the carbide slurry, the higher the ash removal rate at the time of flotation. However, if the concentration is too low, the scale of the flotation machine in the next process will be large. This is not preferable.
[0013]
Next, the slurry is separated into a low specific gravity low ash high carbide slurry and a high specific gravity high ash low carbide slurry using a flotation machine, and then each slurry is solid-liquid separated to obtain a low ash high carbide and a high ash low carbide. to recover. As the flotation machine, a column type flotation machine, a stirring type flotation machine, or the like can be used. Moreover, a filter press, a belt filter, a centrifuge, etc. can be used for solid-liquid separation. Flotation is divided into a low specific gravity low ash high carbide and a high specific gravity high ash low carbide with a specific gravity of 1.4 to 1.8 as a boundary. In addition, each water separated into solid and liquid is appropriately subjected to drainage treatment in order to satisfy drainage standards. In the process of flotation and solid-liquid separation, 80 to 90% of the water-soluble chloride is removed. The recovered low ash high carbide and high ash low carbide slurry can be used together in the cement manufacturing process after being dried.
[0014]
As shown in FIG. 2, the cement firing facility 1 in the cement manufacturing process includes a preheater 2, a calciner 3, a kiln 4, a clinker cooler 5, and the like, and the cement raw material charged into the preheater 2 from the raw material supply system 7 is The clinker produced by preheating in the preheater 2, calcining in the calcining furnace 3 and firing in the kiln 4 is cooled in the clinker cooler 5. The low ash high carbide recovered by the present invention can be blown from the burner 6 in front of the kiln 4 and used as fuel, and can also be put into the calcining furnace 3 and used as a reducing agent. For example, when flotation of an ash-containing carbide having an ash content of about 35% and producing a low ash high-carbide with an ash content of about 10%, the calorific value of the carbide is changed from 4500 kcal / kg to 6200 kcal / kg. It can be used for fuel replacement.
[0015]
On the other hand, the high ash content and low carbide can be input from the raw material supply system 7 to the preheater 2 as a substitute for cement raw clay. When put into the preheater 2, chlorine contained in the high ash and low carbides can be removed by the chlorine bypass facility 8 that extracts a portion of the combustion gas from the vicinity of the kiln bottom of the cement kiln and removes chlorine. Thereby, compared with the case where all the carbide | carbonized_materials are utilized as a fuel before the kiln of the cement kiln 4, more ash content carbide | carbonized_material can be utilized in a cement manufacturing process.
[0016]
【The invention's effect】
As described above, according to the method for using ash-containing carbide according to the present invention, as much ash-containing carbide derived from wastes such as municipal waste can be used in the cement manufacturing process as much as possible.
[Brief description of the drawings]
FIG. 1 is a flowchart for explaining an embodiment of a method for using ash-containing carbide according to the present invention.
FIG. 2 is a schematic view of a cement firing facility in a cement manufacturing process used in the method of using ash-containing carbide according to the present invention.
[Explanation of symbols]
1 Cement firing equipment 2 Preheater 3 Calciner 4 Kiln 5 Clinker cooler 6 Burner 7 Raw material supply system

Claims (2)

Waste-carbonized ash-containing carbide is separated into low-ash high-carbon and high-ash low-carbide, and low-ash high-carbon is used as a fuel for cement production, while high-ash low-carbon is used as a raw material for cement production. Thus, a part of chlorine content contained in the ash-containing carbide is transferred to the raw material side for cement production, and the chlorine content is removed by a chlorine bypass facility . The method for using an ash-containing carbide according to claim 1 , wherein the fractionation method is a flotation method.

Images