JPS606788A - Preparation of aqueous slurry of coal - Google Patents

Abstract

PURPOSE:To prepare a stable aqueous slurry of coal in high concn. at a low cost, by mixing under milling an aqueous emulsion of fuel oil emulsified by application of supersonic wave, with crushed coal. CONSTITUTION:Water 1 and a fuel oil 2 are fed into a supersonic wave tank 4 and the fuel oil is dispersed in fine particles by the action of supersonic energy supplied from a supersonic oscillator 5 to a supersonic vibrator 6 to produce an aqueous emulsion of fuel oil 3. Coal 7 in a hopper 8 is fed into a hammer mill 10 through a batching unit 9 for crushing. The emulsion 3 and the crushed coal 7 are fed into a ball mill for mixing under milling and the resultant concn. slurry of coal 13 is stored in a tank 12 for delivery by emans of a pump 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a stable, highly concentrated coal-water slurry at low cost.

High-concentration coal-water slurry is a slurry with a coal concentration of 70% or more, and because it fluidizes coal using water as a medium, it is intended as a low-cost coal fluidization fuel. In order for a coal-water slurry to maintain stable fluidity, it is necessary for each coal particle to form a water film on its surface, creating conditions for liquid-liquid contact.

However, since the surface of coal has the property of easily repelling water, the moisture in the coal slurry must be minimized (L
7j In highly concentrated slurry, for example, with a water content of 30 g, the coal particles and water do not mix, and the slurry becomes lump-like or has powdery parts, causing problems in transportation and storage.・To prevent this, conventional methods have involved adding a surfactant to the slurry to bond its hydrophilic groups to the surface of the coal particles, making the surface of the coal particles hydrophilic and forming a water film on the surface of the coal particles. , a method has been adopted in which water penetrates between coal particles to lower the viscosity. By this method, the fluidity of the coal particles is improved by contact with the liquid, so it was possible to secure a viscosity of 1000 cp or less even in a slurry with a coal concentration of 70 or more. However, surfactants are expensive, and although they are added in an amount of 0.5 to 1% based on coal, they make the production cost of highly concentrated coal-water slurry high. In addition, since this surfactant is a derivative of fatty acid ester, it is favored by bacteria and may cause corrosion of equipment and pipelines by producing organic acids through deterioration and fermentation.

The present invention solves the above-mentioned drawbacks of the prior art, and provides a method for producing stable high-concentration coal-water slurry at low cost.According to the present invention, fuel oil and water are mixed using ultrasonic energy. Production of a coal-water slurry characterized by a combination of a step of forming a water-fuel oil emulsion, a step of pre-pulverizing coal, and a step of further pulverizing and mixing the water-fuel oil emulsion and the pre-pulverized lime. method is obtained.

Next, the present invention will be explained with reference to the drawings.

FIG. 2 is a system diagram of equipment used in one embodiment of the present invention. In the figure, a weight ratio of 0.5 to 5 cm of water 1 and fuel oil 2 to coal is poured into an ultrasonic tank 4 and an ultrasonic oscillator 5
The ultrasonic energy from is supplied to the ultrasonic vibrator 6 to generate ultrasonic vibrations within the ultrasonic tank 4, thereby dispersing the fuel oil 2 into fine particles.

In the ultrasonic bath 4, an emulsion 3 containing 1.18 to 13.23 of the fuel oil 2 is generated. On the other hand, a certain amount of coal 7 having a diameter of 38 TPn in the coal hopper 8 is weighed with a coal measuring device 9, and is supplied to a hammer mill 10. Grind to a particle size that allows 80% passage through 200 mesh. Next, the mixture of the pulverized coal 7 and the emulsion 3 is further pulverized and mixed in a ball mill 11 to obtain a highly concentrated coal-water slurry 13. The highly concentrated coal-water slurry 13 in the tank 12 is transported by a pump 14 to a destination via a pipeline.

The above-mentioned high-concentration coal slurry is made into a slurry by mixing 70 grams of coal and 30 grams of water, and there is no need for a dehydration process at the place of use, and it can be used together with the shredded boiler fuel or coal gasification raw material. .

Incidentally, FIG. 1 shows a sectional view of the ultrasonic emulsification apparatus disclosed in Japanese Patent Application Laid-Open No. 57-11-9822.

In the figure, 101 is an ultrasonic horn, 102 is an emulsification tank,
103 fuel supply pipe, 104 water supply pipe, 105 pressure pump, 106 flow rate adjustment valve, 107 storage case, 1
08r/'i fuel tank, 109 water tank, 110 inner tank, Ill electrode, 112 electrostrictive element, 113 ultrasonic oscillator, 114 taper part, 115 rubber packing,
1161d: Air hole, 1171r; J column.

- It is la. This device uses ultrasonic energy,
This device is different from the device of the present invention in structure and effect.

The effects of the present invention are as follows.

(1) When a water-fuel oil emulsion is added to coal, the fuel oil, which is turned into small particles by ultrasonic energy, adheres to the surface of the coal, which is a lipophilic hydrocarbon compound, and forms an oil film over the entire surface. Coal particles come into contact with each other using an oil film as a boundary, and because of the so-called lubricating effect, the fluidity of coal particles is much better than that of a water film.

(2) Compared to surfactants, the cost of fuel oil is considerably lower, so the production cost of the highly concentrated water slurry of the present invention is considerably lower.

(3) Fuel oil is mineral-based and is not attacked by bacteria like surfactants made from animal or vegetable oils.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a known ultrasonic emulsification device, and FIG. 2 is a system diagram of the device used in an embodiment of the present invention. In the figure, 1...Water 101-...Ultrasonic horn 2-0...
, fuel oil 102...emulsification tank 14...-pump 1
15-...Rubber seal 1160...Air hole 117... Controller patent applicant Ishikawajima-Harima Heavy Industries Co., Ltd. Agent Yoshi Shirakawa Figure 1

Claims (1)

[Claims] (1) In the process of producing high-concentration coal-water slurry, water and fuel oil are mixed using ultrasonic energy.
11/ A method for producing a coal-water slurry comprising a combination of a step of forming a fulgeon, a step of pre-pulverizing coal, and a step of further pulverizing and mixing the water-fuel oil emulsion and the pre-pulverized coal.