JPS60212490A - Deashing of concentrated aqueous slurry of coal - Google Patents

Abstract

PURPOSE:To effect the deashing of coal in high ash removal and high recovery, by crushing a concentrated aqueous slurry of coal with a wet-pulverizer, recovering the coal having low ash content by flotation, collecting the coal having high ash content from the tail of the flotation apparatus, and recovering the coal from the collected coal by a classifier in the form of flock. CONSTITUTION:A concentrated aqueous slurry of coal composed of 60-85wt% coal, 0.01-5.0wt% surfactant (based on the coal) and remaining part of water, is deashed by the following procedures. The powdery coal 4 prepared by the wetpulverization with a wet-pulverizer is diluted with water 5 in the concentration adjusting tank 41, added with the collecting agent 11 and frothing agent 12 in the conditioning tank 42, sent to the flotation apparatus 43 after agitation, and separated into the coal 13 having low ash content (refined coal) and the coal 14 having high ash content (tail). The tail 14 in the flotation appratus 43 is mixed with a binder 15 such as heavy oil, etc. in the mixer 44. Only the carbon component in the tail 14 having high ash content is coagulated in the form of flock in the coagulation tank 45, and is recovered in the form of flock by a classifier 46 capable of classifying at a particle diameter of 200 mesh.

Description

[Detailed description of the invention] The present invention relates to a method for deashing a highly concentrated coal water slurry.

More specifically, we use a deashing process that incorporates a deashing process to produce high-concentration coal water slurry, which has a high coal recovery rate, a high ash rate, and is highly adaptable to the type of coal. Regarding the method.

The high-concentration coal water slurry is a coal-water slurry fuel composed of 60 to 85 liters of coal, 01 to 5.0% by weight of a surfactant (based on coal), and the remaining weight of water. Coal concentration and surfactant addition ratio vary depending on the type of coal, etc. Coal contains ash, but when combusting coal in a water slurry in a boiler, the presence of ash will reduce boiler efficiency, so it is best to remove as much ash as possible before combustion. preferable. Further, by making the residual ash content in coal the same for each type of coal, it is possible to minimize variations in calorific value and combustion efficiency depending on the type of coal. Based on this unconventional background, Coal High 1, which incorporates the conventional deashing process! The method for producing water slurry will be explained according to the drawings.

Figure 1 is a flow sheet showing 10 processes for producing highly concentrated coal water slurry incorporating a deashing process, and Figure 2 shows details of the deashing process. This is a flow sheet showing.

In FIG. 1, raw coal 1 stored in a raw coal receiving container 21 is supplied to a crusher 23 by a quantitative dispenser 22.

Raw coal 1 is crushed into pure coal 2 by a crusher 25, sent to a pure coal receiving tank 24, and stored there. Pure coal receiving tank 241C
The pure coal 2 subjected to the fg tank is quantitatively supplied together with water 6 to a wet pulverizer 26 by a quantitative supply device 25, where the coal concentration is adjusted to a predetermined coal concentration (10 to 60% by weight),
Specified particle size (particle size 200 mesh pass 70-95 weight 31%
) is wet pulverized into pulverized coal 4. Pulverized coal 4 is coal-
The water becomes a slurry, is received in a raw coal slurry receiving tank 27, and is sent to a deashing device 29 by a pump 28. Details #I of the deashing device 29 are shown in FIG. 51) in Figure 1, and from fCC50, the predetermined coal concentration (5 to 20
The concentration is adjusted to 1%), the collecting agent 11 and the foaming agent 12 are added in the conditioner 42, and after being stirred and mixed, it is sent to the flotation machine 45, and the coal with a low ash content (Jingen) 6 and the ash content are Coal with a lot of
The coal (tail) 7 with a high ash content is removed (deashed) from the pulverized coal 4 by flotation. The coal (tail) 7 with a high ash content is directly sent to the wastewater treatment facility 30 and disposed of.

On the other hand, coal with a low ash content (Jin'en) 6 is dehydrated to a predetermined coal concentration (65 to 90% by weight) by a dehydrator 51 shown in FIG. 1, and the water 5 separated by the dehydrator 31 is It is reused for adjusting the concentration of pulverized coal 4 in the concentration adjustment tank 41. The cake-like coal with low ash content (Jingen) 14 that has been dehydrated to a predetermined coal concentration (65 to 90% by weight and 11%) is
The surfactant 8 is added and stirred in the high concentration slurry adjustment tank 32, and the final coal concentration (6
The concentration is adjusted to between 0 and 85 densities.

The above is a method for producing highly concentrated coal water slurry incorporating a conventional deashing process. However, the above conventional method
Depending on the type of coal, the ratio of coal with a low ash content (Jin'en) 6 and coal with a high ash content (Tail) 7 varies greatly. In other words, the relationship between the coal recovery rate and the deashing rate for coal with a low ash content (Jin'en) 6 tends to be as shown in Figure 4.
It varies considerably depending on the type of coal. For example, if the total deashing rate is increased by changing the type of coal, the coal recovery rate will be lowered and the loss of coal content into the coal (tail) Z with a high ash content will be large. Also, what about the coal recovery rate? If it is increased, the demineralization rate will be low and the demineralization effect will be weakened. Producing highly concentrated coal water slurry e-deashing limited to a specific type of coal is a big problem in a country like Japan where the ratio of imported coal is high. Therefore, it is desired to realize a deashing method that has a high coal recovery rate, a high deashing rate, and is highly adaptable to various types of coal.

Therefore, the present inventors investigated the drawbacks of the above conventional deashing method. As a result of intensive research into the development of a deashing method that has a high coal recovery rate for various types of coal, requires high input, and is highly adaptable, the present invention has been completed.

The present invention uses coal 60 to 85% by weight, surfactant 001 to
In the deashing method for highly concentrated water slurry of coal, which is composed of 5.9% by weight (based on lime and the remaining water content), pulverized coal wet-pulverized in a wet pulverizer is first processed with high efficiency by flotation. By deashing and recovering coal with a low ash content, and then extracting the coal from the coal with a high ash content generated from the tail of the flotation machine, by applying a classifier that can classify the coal with a particle size of 200 mesh,
) Relating to a deashing method for highly concentrated water slurry, which is characterized in that it is collected in the form of four blocks.

FIG. 5 is a flow sheet showing an embodiment of the deashing process according to the present invention, and here, the deashing process 29 in the coal high concentration water slurry production process of FIG. This shows the case where .

In FIG. 3, the pulverized coal 4 sent to the deashing device 29 in FIG. 1 through the same process as in FIG. 5, the concentration pI is adjusted again to a predetermined coal concentration (5% 20% by weight), and the collecting agent 11 and the foaming agent 12 are added under conditions 42, and after stirring and mixing, the coal is sent to the flotation machine 45. The pulverized coal 4 is separated by flotation into coal with a low ash content (sheath coal) 15 and coal with a high ash content (tail) 14, and the coal with a high ash content (tail) is extracted from the pulverized coal 4.
14 is removed (deashed). Coal with high ash content (tail 2
14, a binder 15 such as heavy oil, light oil, kerosene, etc. is dispersed and mixed in a mixer 44, and further in a flocculation tank 45, a binder 15 such as heavy oil, light oil, heavy oil, etc. that has been dispersed and mixed has a high ash content. Only the coal content in the coal (tail) 14 forms flocs (however, the particle size of the flocs is set to 200 mesh (74 μm) or more since the particle size of the pulverized coal 4 mentioned above is 200 mesh or less).

At this time, coal with a high ash content (the ash content in Tailn 14 is
It remains suspended in water as a single particle. When the slurry 16 in such a state is passed through a classifier 46 capable of classifying particles with a particle size of 200 mesh, the above-mentioned coal (floc) 17 containing binder 15 such as heavy oil, light oil, kerosene, etc.
Then, it is separated into ash 7 suspended in water, and coal (floc) 17 is recovered from coal (tail) 14 with a high ash content. Classifier 4 capable of classifying particles with a particle size of 200 mesh
An example of 6 is shown in FIG.

In FIG. 5, the minute R machine 46 includes pan-shaped pans 55 each independently attached to a central shaft 51 via arms 52. A sieve 54 is attached to the inside of the pan 56, and the pan 55 can be rotated in the circumferential direction of a central shaft 510, and the pan 55 itself can be reversed by the arm 52.

Slurry 16 supplied to the classifier 46 having such a configuration
In the dehydration step (A), the water is first introduced onto a flat pan 55, and most of the ash 7 suspended in the water passes through the sieve 5.
4 and a part of it adheres to the charcoal (floc) 17 on the sieve 54.

In the next washing step (B), some of the ash 7 adhering to the coal (floc) 17 is washed away by water spray 55, passes through 1154i, and is separated in the dehydration step (A). It is discharged to the bottom together with the ash content 7. Furthermore, in the coal recovery step (0), the coal (floracne 17) in the #54 soil is washed away by the reversal of the pan 53 by the arm 521C and by water [gs6].
Sieve 54 is recovered from the soil. Finally, in the return step (D), the pan-shaped pan 56 is reversed again by the arm 52, returns to its original position, and is again used for the next dehydration step (N).
to go into. In this way, the XF-silk bread 53 is sequentially moved to the next process by the rotation of the central axis 510, (A)→
The steps (B)→(0)→(D) are repeated.

According to the classifier according to the present invention as described above, the particle size corresponds to the pulverized particle size of 200 mesh in the wet pulverizer (26 in Fig. 1) in the general coal high concentration water slurry production method described above. It is possible to classify heavy oil, light oil, kerosene, etc. with a binder, which was necessary when recovering and separating the entire coal content from coal with a high ash content using a conventional classifier such as a screen.
, 5 = or more, preferably 1.0 = or more, it is possible to eliminate the need for granulation into a pellet shape.

In addition, in the present invention, as a classifier other than the above, a screen R machine having a sieve mesh of 200 meshes, a dynamic classifier such as a vibrating sieve or a centrifugal separator can also be used. Since the strength is weak, the static sieve fractionator λ shown in Figure 5 (that is, the one that allows complete classification without applying a large force necessary for classification to the flocs itself) is preferred.

Examples of operational data for such a deashing process are shown in Tables 1 and 2.
As can be seen from the operation data of the present invention, the flotation machine 4
5. The coal (floc) 17 can be recovered from the separated coal (tail) 14 with a high ash content with high overall efficiency and with a small amount of residual ash, and the deashing method as a whole has a high coal recovery rate. Moreover, it is possible to perform decalcification at a high demineralization rate.

As described above, the deashing method according to the present invention can recover a wide range of coal types with high efficiency and low residual ash content compared to conventional deashing techniques. Even compared to the combination demineralization method using the grain method, it brings about the following effects.

(1) Reduction of binder addition rate.

(2) Significant reduction in tail recovery coal processing time.

(Only the agglomeration time, omitting the granulation time.) (3) Energy saving (reduction of granulation stirring power).

(4) Improvement of deashing rate (prevention of ash entrainment during coal granulation)
hmm .

The coal (floc) 17 containing a binder 15 such as heavy oil, light oil, kerosene, etc. recovered in this way is shown in FIG. ) 15 is sent to the dehydrator 31 in FIG. - After the ash 7 suspended in the water discharged below the classifier 46 is once received in the ash receiving tank 47,
The F is directly sent to the wastewater treatment facility 50 by the pump 48,
Will be discarded. The refined 6 sent to the dehydrator 31 in Fig. 1 is
The coal is dehydrated to a predetermined coal concentration (65 to 95% by weight), and as shown in FIG. (60 to 85% by weight).

Further, the water 5 separated by the dehydrator 61 is reused for adjusting the concentration of the pulverized coal 4 in the concentration adjusting tank 41, as shown in FIG.

In this way, in the deashing process for producing a highly concentrated coal water slurry, the present invention can be applied to a wide range of coal types by employing the deashing process with a high coal recovery rate and high deashing rate.

[Brief explanation of drawings]

Figure 1 is a flow sheet showing the coal-rich water slurry manufacturing process incorporating a deashing process, Figure 2 is a flow sheet showing details of a conventional deashing process, and Figure 3 is a flow sheet showing details of a conventional deashing process.
The figure is a flow sheet showing an example of an embodiment of the deashing method of the present invention. FIG. 4 shows the relationship between the recovery rate of coal into coal with a low ash content (refined) and the deashing rate, and FIG. 5 shows an example of a classifier used in the method of the present invention. Sub-agents 1) Meifuku agent Ryo Hagiwara - Figure 1, Figure 4 Sono Tsukimi Ash Rate (%)

Claims (1)

[Claims] Coal 60-85% by weight, surfactant [1L01-5.0
In the deashing method for highly concentrated water slurry of coal, which is composed of % by weight (based on lime) and % by weight of water remaining, pulverized coal wet-pulverized in a wet pulverizer is first deashed with high efficiency by a flotation method. All of the coal with a low ash content is recovered, and then the coal content is extracted from the coal with a high ash content generated from the tail of the flotation machine.
A deashing method for highly concentrated water slurry, which is characterized in that it is recovered in the form of flocs by applying a classifier capable of classifying at 0 mesh.