JPS6366292A - Production of multipurpose coal-water slurry - Google Patents

Abstract

PURPOSE:To obtain a multipurpose coal.water slurry, ready in handling of pumping, shipping, storage, etc., by subjecting a raw material coal to gravity concentration and wet-grinding coarse grains having low ash content and on the other hand, by wet-grinding an adjusted coal containing fine grains having low ash content to provide slurry. CONSTITUTION:A raw material coal is subjected to gravity concentration to give a low ash coal, medium ash coal and high ash coal and said low ash coal is separated into coarse grains and fine grains. then, deashed coarse grains are subjected to wet grinding with water and a dispersing agent to afford a deashed coal.water slurry. On the other hand, fine-grained low ash coal, medium ash coal and high ash coal are blended to give an adjusted coal which is then subjected to wet grinding with water and a dispersing agent to provide an adjusted coal.water slurry.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a method for producing a multi-purpose coal-water slurry.

[Conventional technology] Coal/water slurry is made by converting coal, which is a solid fuel, into a fluid, making it easy to handle such as pumping, shipping, and storing, and it can be used in power generation and industrial boilers, fluidized bed boilers,
It can be used as a fuel or carbon source in gasifiers, internal combustion engines, etc.

The ash content in the coal of the coal/water slurry consists of inorganic minerals, etc., and when it is burned in a power generation boiler, for example, the ash will partially melt under high temperatures and adhere to the boiler heat transfer surface, causing dirt. Moreover, the heat transfer surface may be worn out, and the heat transfer effect may be reduced.

In addition, when burning in a fluidized bed boiler etc.
Even if some ash is contained, the reaction temperature is relatively low, and most of the ash is discharged from the fluidized bed, so the remaining ash may adhere to the boiler heat transfer surface and cause fouling. It will be reduced.

In this way, the influence of the ash content in coal differs depending on the usage form of the coal/water slurry.

Therefore, when raw coal with a high ash content is used in the production of coal/water slurry for use in power generation boilers, etc.
Deashing treatment is performed during the manufacturing process, and a coal/water slurry with a low ash content is produced with a deashing rate of about 50%.

As a deashing treatment for coal, a method is also used in which coal is washed to a relatively coarse particle size and only low ash coal is pulverized as raw material for coal/water slurry to produce coal/water slurry. However, according to this method, coal other than low ash coal is not used as a raw material for the coal-water slurry, so the yield in coal utilization is significantly reduced.

Furthermore, as a deashing treatment for coal, there is a method of finely pulverizing the coal and flotating the entire amount to convert the suspended matter into low ash coal and the settled material into hard (high ash coal), but deashing treatment equipment Because the unit processing capacity is low, the equipment becomes larger, which not only increases processing costs but also requires a large amount of hard material to be processed.

In order to solve these problems, we have created a multi-purpose coal/water slurry using a single manufacturing method that takes into consideration the utilization form of the final product, the sorting process, and the use of each grade of coal. A manufacturing method is provided. (Refer to Japanese Patent Application No. 61-172421.) [Problems to be Solved by the Invention]However, in the above-mentioned conventional method for producing multi-purpose coal/water slurry, coarse coal and fine coal are separated by mechanical separation of raw coal. Since a step and a separation device are required to separate the two, there is a problem in that the manufacturing method and the device for carrying out the manufacturing method become complicated.

The present invention solves these conventional problems,
The simple process eliminates the mechanical separation process for separating free ash content such as clay from raw coal, and the final product, the coal/water slurry, can be used for multiple purposes, making it easy to use in the sorting process. The purpose of this invention is to provide an excellent method for producing a multipurpose coal/water slurry that can comprehensively utilize each grade of coal that has been sorted under the same conditions.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a method for producing coal/water slurry by converting the raw material coal into low ash coal, medium ash coal,
After separating the low ash coal into coarse particles and fine particles, the coarse particles, which are essentially deashed coal, are fed to a pulverizer together with water and a dispersant, and wet-pulverized. A deashed coal/water slurry is produced, the fine low ash coal, medium ash coal, and high ash coal are blended to form adjusted coal, and the adjusted coal is sent to another pulverizer together with water and a dispersant. The system is designed to produce a prepared coal/water slurry through wet pulverization.

[Function] The present invention has the following effects due to the above configuration. In other words, the raw material coal has been virtually removed from clay and other free ash in a coal preparation factory, and is then directly fed to a sorter for specific gravity sorting, taking advantage of the differences in physical properties such as the sedimentation rate of the coal. The coal is then sorted into low ash coal, medium ash coal, and high ash coal, which have different grades such as specific gravity, ash content, and calorific value.

Low ash coal has a lower ash content than coking coal and has been deashed, so the wet sieve is treated to separate coarse particles and fine particles, which are essentially deashed coal. is led to a deashed coal/water slurry step, which is then fed to a pulverizer together with water and a dispersant, and wet pulverization can produce a deashed coal/water slurry with a low ash content.

Since the fine particles are accompanied by water, the moisture in the fine particles is separated by concentration and dehydration treatment, and then the blend is adjusted to obtain the required calorific value with the selected medium-ash and high-ash coals. It is possible to produce a prepared coal/water slurry by wet pulverization by supplying the prepared coal together with water and a dispersant to a separate pulverizer.

Therefore, according to the present invention, by using a single production method consisting of simple steps, the utilization yield of raw coal is high, the generation of hardness is substantially suppressed, and deashed coal/water slurry and adjusted coal/water slurry are produced. It is possible to produce a multi-purpose coal/water slurry consisting of the following, and it is possible to correspond to the usage form of multi-purpose coal/water slurry.

[Example code] Examples of the present invention will be described below.

In FIG. 1, coking coal 12 in a coking coal bunker 10 has been treated in advance at a coal preparation factory or the like so as not to have an appropriate composition of free ash such as clay, and the coking coal 12 is supplied to a sorter 20. The coal is then sorted into low ash coal 26, medium ash coal 24, and high ash coal 22, which have different specific gravity, ash content, and calorific value. A jig coal separator or the like is used as the sorter 20, and the coal grains are separated by utilizing the settling speed of the coal particles, that is, the difference in specific gravity due to the vertical movement of water. And, under the flotation characteristics between ash content and specific gravity as shown in the reselection curve of coal, 100 parts of raw coal with an ash content of 15.2% has a low ash content of 43 parts with an ash content of 8.6%. It is separated into 57 parts of medium and high weight coal with an ash content of 20.4%.

Here, the medium-ash coal 28 is a mixture of the medium-ash coal 24 and the high-ash coal 22 described above.

The sieve content of the low ash coal 26 with a water content of 15% is wet sieved by a machine 30, separated into coarse particles and fine particles, and has an ash content of 5,
33 parts of the sieved souvenir with 2% ash content becomes deashed coal 42, while 10 parts of the sieved product with ash content of 18.2% undergoes a concentration step 40 and a dehydration step 45 to separate water, and then becomes fine grain low ash content. Charcoal becomes 36. The deashed coal 42 is supplied to a pulverizer 70 together with water and a dispersant, and is wet-pulverized into a coal/water slurry, with coarse particles being classified by a classifier 72 and sent to a pump 7.
A deashed coal/water slurry 78 containing no coarse particles with an ash content of 5.7% is produced by adding a stabilizer and mixing in a kneader 76. Can be used as fuel.

As the fine grinder 70, a tampling mill or the like filled with grinding media is used.

Fine grain low ash coal 36 and medium/high ash coal 28 other than deashed coal 42 are mixed and adjusted to obtain the required calorific value without being discarded, and then adjusted to have a slight ash content. Used for producing coal/water slurry.

That is, the fine low ash coal 36 and the medium/high ash coal 28 have different ash content and calorific value, respectively, and when producing coal/water slurry with such properties,
Since the quality of the product is not good and the benefit of using it as fuel is reduced, the fine low ash coal 36 and the medium/high ash coal 28 are mixed into the adjusting machine 50 at the required weight ratio.
By adjusting the blending, adjusted charcoal 54 having the required moisture content and calorific value is obtained.

At this time, the blend was adjusted using 10 parts of fine low ash coal with an ash content of 18.2% and 57 parts of medium/high ash content coal with an ash content of 20.4%.
67 parts of conditioned coal with an ash content of 20.1% are obtained.

Subsequently, the conditioned coal 54 is supplied together with water and a dispersant to a separate pulverizer 60, wet-pulverized to form a coal/water slurry, coarse particles are separated by a classifier 62, and transported by a pump 64. A stabilizer is added and mixed in a kneader 66 to produce a coal/water slurry 68 that does not contain coarse particles and has an adjusted calorific value, and is used as a fuel in combustion devices such as fluidized bed boilers. can do.

As described above, according to the above embodiment, a multi-purpose coal/water slurry consisting of a deashed coal/water slurry and an adjusted coal/water slurry is produced using a single production method consisting of simple steps from raw coal. This method has the advantage of being compatible with the use of multi-purpose coal/water slurry. In addition, since the raw material coal is used effectively, its utilization yield is high, and the generation of hard material to be discarded is significantly reduced, processing losses in coal utilization can be substantially eliminated.

It should be noted that the embodiments of the present invention are not limited to the above-mentioned embodiments, and various embodiments can be adopted for mechanical separation, sorting, dehydration, blending adjustment, etc.

[Effects of the Invention] As is clear from the above examples, the present invention uses a single production method consisting of simple steps to produce multi-purpose coal and raw material coal, which are composed of deashed coal and water slurry and adjusted coal and water slurry.
This method is designed to produce water slurry, and has the advantage of being compatible with the use of multi-purpose coal/water slurry. Further, raw coal is used effectively, and the utilization yield is high, and the generation of discarded hard particles is suppressed, so there is an excellent effect that processing losses in coal utilization are substantially eliminated.

[Brief explanation of drawings]

FIG. 1 is a flow sheet of a method for producing a multi-purpose coal/water slurry according to an embodiment of the present invention. 12...Raw coal 22...High ash coal 24...
・Medium ash coal 26...Low ash coal 42...Deashed coal 54...Adjusted coal 80.70...Fine crusher 68...Adjusted coal/Water slurry 78...Deashed coal/ Water slurry applicant Kawasaki Heavy Industries, Ltd.

Claims (1)

[Claims] When producing coal/water slurry, raw coal is sorted by specific gravity into low ash coal, medium ash coal, and high ash coal, and after the low ash coal is separated into coarse particles and fine particles, it is substantially deashed. The coarse particles of charcoal are supplied to a pulverizer together with water and a dispersant, and a deashed coal/water slurry is produced by wet pulverization, and the fine low ash coal, medium ash coal, and high ash coal are blended. Adjusted charcoal and pear,
The adjusted coal is fed to another pulverizer together with water and a dispersant,
A method for producing a multipurpose coal/water slurry characterized by producing a prepared coal/water slurry by wet pulverization.