JPS6128588A - Production of coal/water slurry - Google Patents

Abstract

PURPOSE:To obtain a coal/water slurry having uniform properties, by measuring the viscosity of a coal/water slurry at the outlet of a wet-process ball mill and controlling the number of revolutions of the ball mill by the resuting signal. CONSTITUTION:In the production of a coal/water slurry composed of coal 1, water 2 and a surfactant 3 by a wet-process ball mill 4, the coal/water slurry crushed in the ball mill 4 is fed through a viscometer 6 and a discharge line 7 to a product receiving tank 8. In this case, a signal measured by the viscometer 6 is input into a control board 9 and the number of revolutions of a motor 5 is changed according to the diffrence between the preset value and the measured value, whereby the number of revolutions of the ball mill is increased or decreased to give a product having a given viscosity. In this way, troubles such as an impossibility of discharging the slurry from the ball mill due to abnormal thickening can be prevented, the above control serves as a countermeasure to the disturbance of a raw material supply system and the apparatus can be easily controlled.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in a method for producing coal water slurry.

(Prior Art) In recent years, coal-water slurry, which is a mixture of fine coal powder, water, and additives such as surfactants, has been developed as a fuel to replace petroleum.

Coal-water slurry has the advantage of being stored or transported as is and can be handled in the same way as liquid fuel.9 On the other hand, it has constant viscosity and fine powder particle size, which are the most important properties for transportation and atomization for combustion. It is quite difficult to fix the manufacturing conditions to obtain the desired results. This is because it is desired that the 9-coal-water slurry has as high a concentration of coal as possible, and that it is finely powdered (80% or more of 200 Mesosh) and furthermore, that it has a low viscosity (2000 cp or less).

Factors that affect the increase in viscosity include coal concentration, type and amount of additive surfactant.

Coal particle size and particle size distribution 9 Coal type (brand) etc. are mainly mentioned. In order to express the phenomenon of viscosity increase in coal water slurry, Fig. 2 shows an experimental example of the relationship between grinding time in a wet mill and viscosity of coal water slurry, and Fig. 8 shows an example of the relationship between grinding time and viscosity of coal water slurry. An experimental example of the relationship between particle size and grain size is shown.

As is clear from these experimental examples, if the grinding time is insufficient, the resulting coal-water slurry will have a low viscosity but coarse grains, and if the blade is too long, the resulting coal-water slurry will have a small particle size but a high viscosity. It has been difficult to produce a coal-water slurry that has a small particle size, low viscosity, and consistent properties.

(Problems to be Solved by the Invention) The present invention takes into account the above-mentioned characteristics of the coal-water slurry, and provides a coal-water slurry that does not always have constant slurry properties and that is easy to control the production equipment. The purpose of this study is to propose a method for producing slurry.

(Means for solving the problem) The present invention consists of coal, water, additives (usually 2% by weight of surfactant)
In order to produce a coal-water slurry with always constant slurry properties consisting of The viscosity of the coal water slurry discharged from the outlet is measured, and based on the measurement signal,
This is a method for producing a coal-water slurry characterized by changing the rotation speed of a wet ball mill.

(Function) Coal, water, and additives are supplied to a wet ball mill, and the coal is pulverized by rotating twice to produce a coal-water slurry.7. The viscosity of the coal-water slurry discharged from the wet ball mill outlet is measured using a viscometer, and the measurement signal is input to the control panel. If the measured viscosity is lower than the set value, the rotation speed of the wet ball mill is increased and the viscosity is adjusted to the set value. If it's higher, lower the rpm.

In a ball mill, under rotational conditions where the rotational force at the circumferential speed due to nine rotations and the speed at which the balls fall due to gravity are balanced, the higher the speed, the stronger the crushing force is. In other words, in order to reduce the grinding capacity, the speed of the ball mill should be lowered.

As an experimental example showing this, FIG. 4 shows the relationship between the rotation speed of the porcelain ball mill used in the test and the pulverized particle size.

As is clear from FIG. 4, as the rotation speed increases, the particle size of the coal becomes smaller. As the particle size of coal decreases, the viscosity of the coal-water slurry increases. - When the cutting edge rotation speed is lowered, the opposite phenomenon occurs and the viscosity of the coal-water slurry decreases.

(Example) FIG. 1 shows an illustrative diagram of one embodiment of the method of the invention.

In FIG. 1, numeral 1 denotes a coal supply line through which coarse raw material coal is supplied. 2 is a water supply line, and a fixed amount of water is supplied into the wet ball mill 4 together with the surfactant supplied from the surfactant line 3. Reference numeral 5 denotes a motor that drives the wet ball mill 4, and the motor 2 normally operates at a constant speed.

The coal-water slurry pulverized in the wet ball mill 4 passes through a viscometer 6 and is transferred to a product receiving tank 8 via a discharge line 7. At this time, the measurement signal of the viscometer 6 is
The number of revolutions of the motor 5 is changed according to the difference from the set value, thereby increasing or decreasing the number of revolutions of the wet ball mill, thereby making it possible to obtain a coal-water slurry product with a constant viscosity.

Note that depending on the degree of the obtained viscosity measurement signal, it is also possible to input and control the supply amount of the raw material supply system of 1 coal, water, and surfactant, and this is possible in the present invention. Do not hinder the effectiveness of implementation.

(Effects) By carrying out and controlling the production of coal-water slurry according to the method of the present invention, it is possible to obtain a product of coal-water slurry having certain properties. This not only prevents troubles such as the inability to discharge from the ball mill, but also serves as a countermeasure against malfunctions in the raw material supply system, and the equipment is easy to control.

The method of the present invention can be applied not only to the production of coal-water slurry, but also to the management during production of slurry, which is a liquid-solid mixed slurry whose viscosity increases through pulverization.

[Brief explanation of the drawing]

FIG. 1 is an illustration of an embodiment of the present invention, FIG. 2 is a graph showing the relationship between grinding time and coal-water slurry viscosity, FIG. 3 is a graph showing the relationship between grinding time and coal-water slurry particle size, and FIG. FIG. 4 is a graph showing the relationship between the ball mill rotation speed and the coal water slurry particle size. 4... Wet ball mill, 5... Motor, 6... Viscometer, 9... Control panel.

Claims (1)

[Claims] In a method of manufacturing a coal-water slurry consisting of coal, water, and additives using a wet ball mill, the viscosity of the coal-water slurry at the outlet of the wet ball mill is measured, and the rotational speed of the wet ball mill is controlled based on the signal to produce coal with constant properties. A method for producing a coal-water slurry, characterized in that a water slurry is obtained.