JPS5898391A - Coal deashing - Google Patents

Abstract

PURPOSE:To efficiently deash coal in a short time, by adding a small amt. of emulsion oil to an aq. slurry of crushed coal and forming an aggregate of the coal component and the oil by irradiation with a supersonic wave followed by agitation and granulation. CONSTITUTION:Coal is succeedingly crushed by a raw crusher 1 and pulverizer 2, and then slurried by a slurrying machine 3. Emulsion oil 8 consisting of water 5, oil 6 and a surfactant 7 is added to the slurry, and a coal particle and the oil are selectively aggregated due to difference in specific gravity between the coal particle and ash, and difference between wetting properties to water and oil by irradiation with supersonic wave in a supersonic wave aggregation vessel 11, to separate the ash from the coal and disperse it in water. Then the purpose deashed coal is obtd. by introducing the slurry into an agitating granulator 4, in which the aggregate of the coal and oil is granulated, if necessary, with addition of an additional small amt. of oil, and dehydrating the granule by a dehydrator 9.

Description

[Detailed description of the invention] The present invention relates to an improved method for deashing coal by hot oil granulation.

Coal contains lye, which is a major problem when using coal because it causes constant trouble. Therefore, various methods for removing ash from coal have been investigated, and a coal deashing process using oil hot granulation has been established as a promising pulverized coal deashing method.

Hereinafter, a conventional coal deashing method using oil hot granulation will be described with reference to FIG.

Coal is coarsely pulverized by a coarse pulverizer 1 such as a dry or wet jaw crusher, and then further pulverized by a pulverizer 2 such as a dry or wet ball mill. The finely pulverized coal is prepared into a suitably thickened coal-water slurry in a slurry preparation tank 6, and then sent to the stirring granulator 4. On the other hand, aquarium 5
, oil tank 6, surfactant? Water, oil, and surfactant are fed into the emulsion preparation tank B, emulsified, and fed into the stirring granulator 4.

In the stirring granulator 4, coal and oil are combined and granulated, and the ash remains dispersed in water. The granulated pellets are dehydrated by a dehydrator 9 and taken out as deashed coal.

However, in the coal deashing process using the conventional oil-temperature granulation method described above, (1) the granulation time is long, making it difficult to downsize the apparatus; ■It has the disadvantage that it requires a large amount of oil addition, which is economically disadvantageous.

Therefore, the present inventors have conducted intensive research into a method that can eliminate the drawbacks of the conventional method, shorten the oil-cooled granulation time, downsize the device, and reduce the amount of added oil. As a result, we first made finely ground coal into a water slurry, added a small amount of emulsion oil to this, mixed it uniformly, and irradiated the mixture with ultrasonic waves for a short period of time (several seconds) to form aggregates of coal and oil. When the aggregates are granulated with oil cooling, the granulation property is improved, and the oil is evenly adsorbed on the coal surface, which improves efficiency. It was confirmed that the device could be made smaller by shortening the grain time.

The present invention was completed based on the above findings, and is an oil-cooled granulation method that uses the difference in wettability of coal and coal-containing ash to water and oil to separate coal and ash. In the first stage of granulation, a small amount of emulsion oil is added to a water slurry of coal containing 1i% if powder and irradiated with ultrasonic waves to form agglomerates of coal and oil, which are then stirred and granulated to remove ash from the coal. The gist of this paper is a coal deashing method that is characterized by the following.

The present invention will be described in detail below with reference to FIG.

In FIG. 2, components with the same reference numerals as in FIG. 1 have the same functions and effects, so a description thereof will be omitted.

In the figure, 10 is a mixing tank, which uniformly mixes the coal slurry fed from the slurry preparation tank 6 and the emulsion oil fed from the emulsion preparation tank 8X5. This mixing tank 1
0 is used by the state ink mixer in the bi-to-line. In the figure, reference numeral 11 denotes an ultrasonic aggregation tank, which irradiates ultrasonic waves from an ultrasonic vibrator installed in the tank to coagulate pulverized coal and oil.

Particles in water differ somewhat depending on the wettability of their surfaces, but due to the resonance of particles and water, the ratio (amplitude ratio) of particle amplitude Xp to medium (water) amplitude Xg is 0, as shown in the following equation.
．． When the ratio is 2 to 0.8, the particles agglomerate, and when the ratio is other than that, they are dispersed. Considering the behavior of coal particles and ash in coal when irradiated with ultrasonic waves, coal and oil selectively form aggregates due to the differences in specific gravity and wettability of each particle to water and oil. As a result, the aggregates and lye are considered to be separated and dispersed in water, which in turn leads to separation of coal and ash. At this time, when the coal slurry concentration increases, the ultrasonic waves are attenuated and the efficiency decreases, so the slurry concentration! It is desirable that it is below ID%.

The ultrasonic irradiation method in the ultrasonic coagulation tank 11 is shown in Fig. 6A.
-E VC It is possible to adopt various means as shown. That is, FIG. 5A shows a case in which a vibrator 11A is arranged at the bottom of the inverted-shaped vibrator-like coagulation tank 11, and FIG. In Fig. 6C, vibrators +1 are placed alternately on the side of the vibrator-like coagulation tank 11
The fifth figure shows a vibrator in which a cylindrical vibrator 1i is disposed in a vibrator-like coagulation tank 11, and the third figure E shows a vibrator surrounded by a cylindrical vibrator 11A. A hollow reflecting plate 11B is disposed in the center of the coagulation tank 11.

In addition, using a sieve with an opening of 74 microns, 70 to 80% of the bottom of the sieve
For pulverized coal, the effective ultrasonic frequency range is 200-1(]O[lKc, especially 400-6D
The range of CI Kc was good.

The emulsion oil can be added either by dividing it into the mixing tank 10 and into the stirring granulation tank 4, or by adding the entire amount before the mixing tank 10, but in the former case, the amount of emulsion oil added is mixed. The front tank 10 is the main tank, and the stirring mixing tank 4 is the secondary tank. Preferred specific ratios include 7 to 9 in the front of the mixing tank 10 and 3 to 10 in the stirring mixing tank 4.

By using the above-mentioned method of the present invention, the aggregation time required to form agglomerates of oil and coal is long in the conventional agitation granulation method, but by adopting the ultrasonic irradiation method, the aggregation time can be significantly shortened. Moreover, since the granulation properties are improved by ultrasonic irradiation compared to conventional methods, it is possible to create coal/oil aggregates even with a small amount of added oil, which can then be processed as is. Two methods can be adopted: granulating or granulating by adding a small amount of oil, but either method has the effect of saving oil compared to the conventional method.

50~60mm lump charcoal is crushed using a hammer crusher.
After coarsely pulverizing the powder to a particle size of 5 am or less, the powder was further pulverized using a dry ball mill using a sieve with an opening of 74 microns to about 70% below the sieve, and used in the test.

Approximately 300 ml of this was made into an approximately 5% water slurry with a beer strength of 500 Tnt, and emulsified with C heavy oil (water: oil: surfactant = 50:50:05, example of surfactant: lauric acid monomer). After adding 3% esterne to the coal and stirring by hand for 1 to 2 minutes, the mixture was irradiated with ultrasonic waves at a frequency of 400 K and c for several seconds using an ultrasonic generator. A stirring granulation test was conducted using the following.

In Fig. 4, the earthwork is a batch stirring granulator, 41 is an 85φX 500 amO granulation tank made of acrylic resin, 42 is an impeller installed in the granulation tank 41, 45 is an agitator for the same impeller 42, and 44 is an agitator for the same impeller 42. This is a constant temperature bath placed so as to surround the granulation tank 41.

The stirring granulation test was conducted using emulsified heavy oil C and surfactant 50. After adding [l ppm (based on coal)], the granulation time was set to 2 hours, the mesh size was opened after granulation, the sieve was classified using a 5TIa sieve, and the granulation properties were examined from the amount of coal remaining on the sieve.

The analysis results of the coal and C heavy oil used in the test are shown in Tables 1 and 2.

Table 6 shows the results of a comparison of changes in granulation properties when the amount of added oil was increased, with and without ultrasonic treatment. As a result, it was possible to reduce the amount of added oil by approximately 3% by performing ultrasonic treatment.

In addition, Table 4 examines the granulation properties when the amount of added oil is 27% compared to coal, and it is confirmed that the granulation time can be shortened by about 15 minutes by ultrasonic treatment. .

As described above, the present invention has been found to be a very useful method that can shorten the granulation time and reduce the amount of added oil in the oil-cooled granulation and deashing method.

Table 1 Table 2 Table 3 (Note)
0 or less ○ Amount of added oil that is granulated (more than 90 inches on a sieve) 2 The amount of oil itself is shown, but the emulsion is used for addition.

Table 4 (Note) The amount of added oil was 27 wt% relative to coal.

As the added oil, emulsion oil of C heavy oil was added.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing a coal deashing method using the conventional oil hot granulation method, and FIG. 2 is a flow sheet showing a coal deashing method improved from the method shown in FIG. 1 of the present invention. FIG. 3 is a diagram showing a specific method of ultrasonic irradiation used in the method of the present invention, and FIG. 4 is a sectional view of a batch stirring granulator. Sub-agents 1) Clearance agent Ryo Hagiwara - 61C, 8-3 A B C Figure D E

Claims (1)

[Claims] The oil-hot granulation method uses the difference in wettability of coal and coal-containing lye to water and oil to separate coal and lye.
Before performing hot oil granulation, a small amount of emulsion oil is added to the water slurry of the pulverized coal, and ultrasonic waves are irradiated to form coal and oil aggregates, which are then stirred and granulated to extract lye from the coal. A coal deashing method characterized by removing.