JPS60203697A - Production of deashed high-concentration slurry - Google Patents

Abstract

PURPOSE:Only low-density coal is converted into coal-water slurry among coarse particles of crushed coal and subjected to flotation whereby high-concentration slurry of high deashing is obtained. CONSTITUTION:Coal as a raw material is sent to crusher 1 and sieve 2 and separated into coarse powder and fine powder. Only coarse powder is introduced into heavy liquid cyclon to remove particles of high specific gravity and the resultant low-density particles are combined with the above-described fine powder. The mixture is sent to wet-type crusher 4 where the paticles are made into a slurry of ultrafine particle coal, introduced into flotation selector 5 where a foaming agent is added to effect deashing by flotation. Then, water is removed and the product is sent to the kneader 7 to mix with a slurry-forming agent thereby deashed high-concentration slurry is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly concentrated deashing slurry, and more specifically, the present invention relates to a method for producing a highly concentrated deashing slurry. Concerning decalcification methods.

Coal liquefaction, gasification, C
Fluidization technologies such as OM are being developed, and one of these fluidization technologies is a highly concentrated coal-water slurry. This slurry contains 70 to 80 coal particles of 74μ or less.
Finely pulverized until it contains approximately 65-75% coal and 3% water.
The weight ratio is 5 to 25%.

It is also possible to use ultra-finely pulverized charcoal of 100% finer grain size of 43μ or less. In either case, the addition of a slurrying agent has the advantage that the coal has fluid properties even at the above coal concentration and can be handled in the same way as conventional petroleum fuel.

However, even though it has become possible to process coal into a slurry in the same way as petroleum fuel, this does not mean that the problem of processing the ash content in coal has been solved. That is, the ash not only abrades the boiler walls during combustion, reducing combustion efficiency, but also makes transportation costs uneconomical.

Therefore, when using raw coal with a relatively high ash content, a method has been proposed in which the coal is finely pulverized in order to reduce the ash content, and then the entire amount is deashed. However, if this method is adopted, the deashing equipment becomes larger and the processing cost increases, and sufficient deashing effects cannot be obtained.

The purpose of the present invention is to solve the above-mentioned problems, and to provide a method for producing a highly concentrated deashed slurry in an economical manner, which allows sufficient deashing even when coal with a relatively high ash content is used as raw coal. We are here to provide you with the following.

The present inventors separated coal according to its specific gravity and examined the state of ash provision in the coal, and found that the t1 half of the ash had a specific gravity of 1.5 to 1.
It is contained in heavy coals with a density of 6 or more, but even if this heavy coal is finely pulverized and then flotated, it does not show a significant deashing effect and is difficult to flotate, while coals with a low specific gravity tend to float easily. The present invention was completed by focusing on the fact that flotation also has a large deashing effect.

That is, the present invention is a deashing method characterized in that high-density coal is removed from coarse-grained raw coal, and only the remaining low-density coal is made into a coal-water slurry, followed by flotation deashing. This is a method for producing high concentration slurry.

The figure shows one embodiment of the invention. 15m by crusher 1
The coal crushed to a certain extent is separated into coarse powder (more than 0.5 m thick) and fine powder (less than 0.5111 m) using a sieve 2. The coarse powder is introduced into heavy liquid cyclone 3, where the specific gravity is 1.5 to 1.
．． Heavy particles of 6 or more are removed from the bottom of the heavy liquid cyclone 3, mixed with fine powder from the coal sieve from which heavy coarse particles of 1 specific gravity have been removed, line 11, and introduced into the wet crusher 4 through line 12. . Here, finely pulverized coal containing about 70 to 80% of particles of 74μ or less, or finer ultra-fine pulverized coal, is adjusted to a slurry with a coal concentration of about 1 to 10%.
3. It is introduced into the flotation machine 5. Flotation is 0.0% per coal.
05-0.3%, preferably 0.1-0.25% collector and 90.02-0.15%, preferably 0.03-0.1% superfoaming agent based on coal. The coal slurry is then deashed to form a coal slurry with a concentration of 15 to 30%, preferably 18 to 25%. The flotated and deashed coal is further sent to a dehydrator 6 through a line 14 and dehydrated to a moisture content of 25 to 35%. After that, it is sent to the kneading machine 7 through line 15,
Here, it is kneaded together with the slurrying agent from the slurrying agent injector 8 to form a highly concentrated demineralized slurry. In addition to a heavy liquid cyclone, the removal of coarse particles with high specific gravity may be performed using a jig, a wet cyclone, etc. depending on the particle size of the crushed coal, the ash application situation, etc. Furthermore, if possible, the crushed coal may be directly introduced into the heavy liquid cyclone without passing through the sieve 2.

In the present invention, the slurry agent is used to stabilize the fluidity of the slurry, and anionic, cationic, and nonionic surfactants are used alone or in combination, and are appropriately selected depending on the type of coal. . To give specific examples, examples of anionic surfactants include fatty oil sulfate salts, higher alcohol sulfate salts, nonionic ether sulfate salts, olefin sulfate salts, alkylaryl sulfonates, and dibasic acid ester sulfones. Acid salts, dialkyl sulfosuccinates, acyl sarcorsinates, alkyl hensensulfonates, alkyl sulfate ester salts, dialkyl sulfosuccinate ester salts, alkyl acids and/or maleic anhydride copolymers, polycyclic aromatic sulfonates Alternatively, formalin compounds can be exemplified. In addition, as cationic surfactants, alkyl amine salts, quaternary amine salts, etc. are used, and as nonionic surfactants, polyoxyalkyl ethers,
Polyoxyethylene alkylphenol ethers, oxyethylene/oxypropylene block polymers, polyoxyethylene alkylamines, polyoxyethylene sorbitan fatty acid esters, and oxyethylene sorbitan fatty acid esters are used.

According to the present invention, since coal that is difficult to float is removed in advance, a high deashing rate can be obtained, and the productivity and economic efficiency of the slurry are substantially increased.

Hereinafter, the effects of the present invention will be specifically illustrated by examples.

Example A deashing test was conducted using coal whose ash application conditions were as shown in Table 1.

As an example, after removing coarse particles with high specific gravity (specific gravity 1.6 or more), a slurry with a coal density of 80% below 74μ and adjusted to a coal concentration of 5.3% was subjected to flotation and deashing.

As a comparative example, the entire amount was subjected to flotation and deashing without removing high specific gravity coarse particles. The test results are shown in Table-2. In addition, in Table 2, A and Z set flotation conditions for the purpose of obtaining a high combustible material recovery rate, and B and 〆 conducted flotation under conditions that changed the above-mentioned 4-return conditions. It is something.

(Left below) As is clear from the test results, according to the present invention, coal that is difficult to flotate is removed in advance, so compared to deashing using the total flotation method, it is possible to obtain the same level of combustible recovery rate. It can be seen that a high demineralization rate can be obtained with

[Brief explanation of the drawing]

The figure shows one embodiment of the invention. 1... Crusher 2... Sieve 3... Heavy liquid cyclone 4... Wet crusher 5...
Flotation machine 6... Dehydrator 7... Kneading machine

Claims (1)

[Claims] 1. Production of a highly concentrated deashed slurry, which is characterized by removing high-density coal from the coarse-grained raw coal, turning only the remaining low-density coal into a coal-water slurry, and then performing flotation and deashing. Method.