JPS59147088A - Preparation of coal-water slurry - Google Patents

Abstract

PURPOSE:Additives are added to a high-concentration coal-water slurry and they are stirred vigorously, further water is added, which stirring, to a prescribed concentration to give a coal-water slurry of high flowability and stability. CONSTITUTION:For example, coal is crushed into fine particles, until 70-80% of the particles can pass through about 200 mesh, in case of dry crushing, water is added, when crushing is effected by the wet process, dehydration is effected to adjust the coal concentration to about 20-25%. About halves of additives such as dispersant or stabilizers to be added in appropriate amounts are added to the slurry and they are vigorously stirred with an agitation mechanism for about 5-20min. Water is added to the resultant slurry, the remaining halves of the additives are added and stirring is continued to give the objective coal- water slurry of a desired concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preparing a coal-water slurry having excellent fluidity and stability.

One way to handle and use coal in the same way as liquid fuel is to make a slurry of pulverized coal and water.In terms of transportation costs, calorific value, etc., it is advantageous to have less moisture, so it is possible to maintain the properties of coal as a liquid. Efforts are being made to increase the concentration of coal as much as possible.

The main of these measures is the addition of chemicals to completely aid in the dispersion of coal and to increase the stability of the slurry. By adding .5% of chemicals, it is possible to obtain a stable slurry with a coal concentration of about 70% (moisture content: 30%).

It is generally known that when all spheres of the same diameter are placed tightly together and stored in a container, a void of about 7% of the total volume is created, and the particles are irregular in shape and vary in particle size, like fine coal powder. In some cases, this void volume should become even smaller, but in reality, the voids of large particles are not completely filled with small particles, which is an obstacle to increasing the solid content concentration.

It is also effective to create two peaks in the particle size distribution in order to fill the voids in large particles and improve fluidity, but this method also requires the use of an operation that fills the voids.

The present invention provides a method for preparing a coal-water slurry that can further improve fluidity and stability when the coal type, particle size, distribution, coal concentration, additives, etc. are the same.

That is, the present invention is particularly characterized in that when preparing a slurry, strong stirring is performed in the presence of an additive at a coal concentration higher than the target coal concentration, and then the slurry is stirred four times to reach the target concentration. , which allows particles of small size to be forced into the voids of coarse particles.

Hereinafter, the method of the present invention will be explained in detail based on one embodiment of side sounds.

Coal is finely pulverized to about 70 to 80% by 200 mesh passes, and water is added if the pulverization is carried out completely dry, and water is dehydrated if the pulverization is carried out wet to adjust the coal concentration to 20 to 25%.

An appropriate amount of additives such as a dispersant and a stabilizer are added to this, and the mixture is strongly stirred using a stirring device for about 5 to 20 minutes.

Although the type of dispersant and stabilizer does not matter, it is preferable not to add the entire amount of gold assumed in advance, but to gradually add about 1/2 of that amount.

In addition, a relatively low-speed mixer is suitable for the stirring device.
The type does not matter.

Water is added to the obtained slurry, the remaining amount of the additive is added, and further stirring is carried out to obtain a coal-water slurry of the desired concentration.

By the way, if a highly concentrated coal-water slurry is strongly stirred, the coal particles will immediately bond to each other, forming a collection of coarse particles.However, by continuing to stir, this bond will break down again and small particles will be dispersed. The particles are arranged so as to fill the voids between the large particles. The stronger the agitation, the stronger this action is, so it is preferable to perform all the agitation with highly concentrated soft stools within the range permitted by the required power. For example, coal concentration 70
% slurry, compared to mixing at 70% from the beginning, mix at 75% and then mix at 70%.
%, it is possible to obtain a slurry with better fluidity and stability.

In addition, in the method of the present invention, the types of additives (dispersants, stabilizers, etc.) used in preparing the slurry are not particularly limited, but
The use of suitable additives is essential.

In addition, in the method of the present invention, it is even more effective if several percent or more of ultrafine powder is mixed into the pulverized coal, for example, pulverized coal of 70% or more of 500 mesh pass is mixed, and these ultrafine powders are not limited to coal. Petroleum coke, charcoal, etc., which require less power for pulverization, may also be used.

According to the method of the present invention described above, it is possible to obtain a coal-water slurry with a high coal concentration, and it has been confirmed that it is also extremely effective when a pigment is mixed into a paint.

Sub-agent: 1) Akira Sub-agent Ryo Hagi Hara -

Claims (1)

[Claims] (11) A pulverized coal characterized in that it is strongly stirred in the presence of an additive at a concentration higher than a predetermined coal concentration, and then water is added and further stirred to reach a predetermined concentration. Method for preparing water slurry. (2) The method according to claim (1), in which the additive is added separately during stirring at a high concentration and during stirring at a predetermined concentration.