JPS6155516A - Preparation of coal fuel - Google Patents

Abstract

PURPOSE:To facilitate conversion of fuel for medium and small types of boilers into coal by a method wherein after having been pulverized, the pulverized coal are classified in a multi-stage by a narrow range of particle size, the respective sort of coals classified are treated as products thereof. CONSTITUTION:Drying out and crushing of raw coal (b) are performed simultaneously in the impact type coarse crusher 1, and the coarse pulverized coal (c) having overcome the upstream current in a coarse crusher, are recovered by a classifier 3. The dried coarse pulverized coal riding on a hot air stream current in the coarse crusher, are stored successively in the hopper 6. The pulverized coal group in the pulverizer 10 at a low flux rate are dropped into a multi-stage classifier 12, which are separated by a particulate diameter as the secondary and the tertiry products (d), (e) respectively, and the remaining ultra- pulverized coal riding on a air stream current are totally recovered by the bag filter 13, which are classified as the ultra size of below 15mum, the quartic product (f), and are recovered. By this production mechanism, it is possible to facilitate the fuel conversion for the medium and small type boilers into the coal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to boilers of various capacities by pulverizing coal into 1a and then classifying the crushed coal in multiple stages to produce classified coal with a narrow particle size differentiation range. This invention relates to a method for producing coal fuel with reasonable combustibility.

Conventional Technology Since coal has more coal reserves than oil and is cheaper in combustion tunnel costs, it is required to convert the boiler/strand F-1 from heavy oil to coal.

Conventionally, it has been known that by applying process reflux to coal to make it super efficient (115), it can be applied not only to small and medium-sized boilers but also to oil-fired boilers. This has been achieved by crushing the entire amount of coal, which is not economical for small and medium-sized boilers, and it is difficult to popularize coal conversion by crushing the entire amount.

Problems to be solved by the invention Small and medium-sized boiler fuel JSI for general industrial use (in the case of converting the separation method, boiler fuel) 6-chamber 1111 structure, size, boiler tube arrangement, burnout of solid coal particles Due to speed and other factors, the particle size distribution of coal fuel is limited by the size of the boiler, which also causes a delay in the transfer of P to coal.

In a charcoal-fired boiler, if the fineness of the coal is improved, it will be possible to switch to a curve-fired boiler, or to convert to a small-sized boiler, where it is difficult to improve combustion efficiency with conventional coal-fired boilers.
However, in order to increase the total amount of coal, the crushing power increases depending on the required fineness, which impairs the characteristics of coal, which has a low fuel unit price, making it uneconomical. .

Also, when converting general industrial boilers to coal,! l:'
j / (Users are in difficult situations due to problems such as location, coal availability, ash disposal, etc., but the coal can be centrally processed at one call center, etc., and transported and delivered to the targeted radius) Various studies have shown that economic efficiency can be achieved by doing this. However, in the past, due to the above-mentioned rationale, it was difficult to convert all small and medium-sized boilers that exist within the economic and distribution range.

The present invention has been developed in view of the above points, and it makes it easier to switch to coal as fuel for small and medium-sized boilers, and it also makes it easier to convert coal into fuel for small and medium-sized boilers. A fuel tank suitable for its size and characteristics
-1- is supplied at a low cost, making it possible to apply coal-converted boilers and expand the head circumference, and optimal combustion suitable for each size of boiler distributed within the above-mentioned economic transportation area. A method for producing coal fuel is provided to provide coal with an optimal narrow particle size distribution that provides efficiency.

Pause: Vertex? The method for producing coal fuel of the first invention includes pulverizing coal, and then classifying the pulverized coal in multiple stages to obtain narrowly classified coal with a grain size of 2 heads; The method for producing coal fuel according to the second invention is characterized in that each classified coal is used as a product, and the method for producing coal fuel of the second invention coarsely pulverizes coal to obtain coarse granulated coal and coarse charcoal, and adjusts the particle size of this coarse granulated coal. The method is characterized in that, after imitating and improving the coarse charcoal, the magnetically pulverized charcoal is classified in multiple stages to obtain classified charcoal having a narrow particle size range, and each classified charcoal is made into a product.

Therefore, the present invention solves the problem of increased power caused by excessively finely pulverizing coal, and by performing excessively fine pulverizing, it takes advantage of the physical properties of coal to produce everything from coarse-grained coal to ultra-fine coal. To provide a large number of users with boilers of various power outputs with coal fuel that is classified and has excellent flammability and has a narrow particle size distribution that is suitable for each boiler scale and has a narrow particle size distribution range. I can do it.

In addition, the present invention eliminates the disadvantage of increased power due to excessive crushing of the entire amount of coal, takes into full consideration the special characteristics of the grain size of coal, and eliminates the ash content, which is the biggest defect of solid fossil fuels. By reducing excess marginal crushing and concentrating it in a certain particle size range and recovering it, classified coal in a certain particle size range can be expected to have a deashing effect. It is suitable for high-efficiency combustion in a gas locator.

In the present invention, the classification and recovery of crushed coal is carried out using vibration wires,
This is carried out using a special classifier, etc., and coal fuel is produced by adjusting the diameter of the particles to be classified and recovered and the particle diameter +'HiJL range depending on the balance of the scale of the boilers existing in a certain supply area. In the present invention, the coal is subjected to [stage], preferably two stages, of low reflux pulverization to create optimal fuel conditions for each boiler power and type. In the case of a fluidized bed boiler, after recovering the coarse particle size coal that is most suitable for the fluidized bed boiler using a two-stage method,
[Bottom] In the case of single-stage coal, the coal is placed in a low-flow frame, classified by coal particle size using the same concept as Ishiura Sensei, and divided into small "i-grade charcoal" by particle size. Coarse-grained product coal is used as fuel for relatively large industrial boilers, medium-grained coal is used as fuel for medium-sized boilers equipped with a combustion stage that can process high-ash coal, and ultra-starved coal is used as fuel for medium-sized boilers that can process high-ash coal. By making Shimoura Shina coal with an ash content of 1/8 ash for small boilers, it is possible to convert to coal by making minimal modifications to oil-fired boilers.As described above, the present invention By appropriately pulverizing coal and classifying it in multiple stages, it is possible to increase the classification point from coarse granulated coal to 1.
This can also be called a co-manufactured process.

EXAMPLE Hereinafter, an example of the present invention will be explained in detail based on the drawings.

Example 1 As shown in Fig. 1, raw coal unmixed or blended coal (hereinafter referred to as raw coal) that has been adjusted to have a grain size of 50.rlJn or less by a raw coal receiver (not shown) is used. ) is supplied in a fixed amount to the impact type coarse crusher 1 with ventilation and circulation type.

Hot air generated by a hot air generator 2 using fuel such as heavy oil, light oil, kerosene, or coal and adjusted to an appropriate temperature and low oxygen concentration is blown into the coarse pulverizer 1, and raw coal is produced in the coarse pulverizer 1. Drying and grinding are performed simultaneously. in this case,
The flow rate inside the crusher cylinder and the flow rate at the outlet are adjusted to obtain coarse coal that matches the purpose, and the coarse coal that has overcome the upward flow rate inside the coarse crusher is coarsely crushed (discharged from below and passed through a vibrating sieve, etc.). With the classifier 3, for example, the particle size is 3~l Q E
Coarse coal sized into LM is recovered. For example, the 1st rank coal remaining on the sieve of the classifier 3 is returned to the raw coal supply tray or the coarse crushing installation and is crushed again. It is desirable to do the precept of becoming (and breaking) on New Year's Day.

Inside the coarse crusher 1:! '1) Dry charcoal having a grain size of 8 mm or less, carried by the wind velocity, is collected in its entirety by means such as Zyclone 4 or bag filler 5, and is continuously stored in hopper 6. Passed bug filling 5 etc.
? h'' A part of the purified hot air is released into the atmosphere from the discharge pipe 7 as dry moisture of the coal and combustion surplus gas, and the remaining hot air is circulated to the hot air generator 2 through cooling d8. The R-ring for feeding hot air into the hot air generating furnace from the bag filler 5 serves to lower the oxygen concentration, and the cooler 8 in the circulation line serves to lower the dew point of the hot air.

The coarse coal stored in the hopper 6 is pulverized by the pressure inside the pulverizer 10 (2) while maintaining an appropriate minimum storage height to prevent atmospheric discharge due to wind and parallel flow of fine powder. The pulverized coal 1', 11 supplied to the pulverizer 10 is supplied to the crusher 10 by the fixed quantity supply 1i1s11.The crushed coal 1', 11 supplied to the pulverizer 10 has already been dried and crushed in the previous step to a particle size of 3111 N or less and a moisture content of 5% or less. Therefore, the crushing capacity of the i-pulverizer 10 is 1.5 to 2 times higher than that of direct dry crushing using the constant humidity moisture method with a particle size of 50〃R or less.
．． This is 5 times more efficient, making it possible to perform economical pulverization.

The continuous operation of the enemy crusher 10 is to increase the internal recirculation and crush the ash to the state of magnetic powder in order to increase the initial degree of rinsing as much as possible so as to increase the combustion efficiency in the pulverized coal boiler. Therefore, the power cost increases, but in the method of the present invention, the pulverized coal that has passed through the pulverizer] is passed through an efficient multi-stage classifier 12.
The waste is collected by particle size. Since the internal reflux in this waste pulverizer can be lowered, the ash content can be concentrated in some particle sizes i1 & 21ffl as described later, so depending on the particle classification, a classifier with a low ash content can be produced. This can be expected, and power costs can be further reduced.

The charcoal group crushed at a low reflux rate in the shank pulverizer 10 is fed into a multi-stage classifier 12, and is divided into grains with a particle size of, for example, 0.3 to 4.
It is separated into the 4μ group (secondary product) and the particle size 44μ to 15μ group (tertiary product), and the remaining super enemy powder carried by the airflow is collected in its entirety by the bag filler 13, and the 17th particle group with a particle weight of 5μ or less (fourth grade) is collected. Collected as next product). Reference numeral 14 is a hot air generator for coarse pulverization (of the same type as in the previous case). Hot air from the bag filler 13 is circulated to the hot air generator 14 via a cooler 15.

Due to hot air circulation! The oxygen concentration is reduced and the dew point in the hot air can be lowered by installing a cooler in the circulation line.

Although a multi-stage classifier is shown in the drawing, it is also possible to construct a TI'iff by connecting multiple classifiers in series to perform classification in multiple stages. It also shows the case where the enemy's crushed coals are divided into 3 groups, but 2+! 'It may be divided into 1 or 4 or more groups.

The classification point in the case of classification can be freely changed by adjusting the set point in classification 3g12, and can be selected depending on the required particle size range and amount of the target product. The resulting classified amount of ring products is 10 to 20 tons for the mastic particle meter (-next/ridge product), and 45 to 50 tons for the secondary products, with the input raw coal being 100 on a dry coal basis.
Bun-U%, tertiary ω product enemy group is 25-281 pillar amount%, and quaternary product super forged costume 1 is 10-12jjj]i%.

These values vary somewhat depending on the type of coal, the pulverization method, and the reflux rate inside the rock, but they can be achieved by crushing with a two-stage pulverization method and an internal reflux rate of 2, as in the Motoya example. Each classification yield is within the above-mentioned range.

No. 3 shows the particle structure of each particle group obtained by this example. It can be seen from FIG. 3 that a classifier with uniform particles having a narrow particle size and head circumference can be obtained. The use of the Qiwa charcoal collected by the branch is that the quaternary product, the super starvation charcoal, is mainly used for evaporation of 1
It is most suitable as a fuel for small industrial boilers of 0 t/h or less, has low ash content, short flame length, can be used for XΔ with little reduction in capacity with minor modification of existing boilers, and has a narrow particle size distribution; [ Since the α surroundings are uniform, a uniform combustion velocity can be obtained, and combustion can be easily controlled. Tertiary products and secondary products have an evaporation rate of 3. It can be applied to industrial boilers with an evaporation rate of 30 t/h or less and an evaporation rate of 30 t/h or more. 50υ"2 and β evening glow control becomes easier.According to the 4th diagram, since the ash moth reaches its fruition in the secondary and product starvation coal group 1, It is possible and effective to use combustion equipment that has a pre-combustion chamber and can remove ash.

-The coarse particles of the next product are coarse particles that perform undercutting, so they are the most suitable fuel for fluidized bed boilers.
Conventionally, the biggest problem for fluidized bed boilers, which is the rule of 1 quantity 1 yen for quantity j, can be eliminated in one go by 19 terms.

The products obtained by the method of the present invention are stored in product silos kept in an inert state to prevent quality deterioration due to product oxidation, and are stored in closed lorries or used as secondary products. Although it is possible to transport coal to the west by regular trucks, it is especially important to transport coal that has a low bulk density and is likely to generate dust per minute. It is also possible to transport the slurry by mixing a few percent of heavy oil beforehand to make oil-sweetened coal, or by using liquid carbon dioxide gas as shown in USP 4,206,610, which is perfect for transporting large quantities of super e-carriages. It is also possible to adopt a closed system. Furthermore, to adjust the amount of products due to changes in the user's ability, adjust the set point of the classifier 12 as described in 1.IJ to adjust the amount of each product group according to the purpose of use. This is done by appropriately blending secondary to quaternary products of bamboo shoots and adjusting the amount. In addition, in order to improve the yield of super and charcoal groups (fourth product), secondary products,
Tertiary products may also be recycled.

Example 2 As shown in Fig. 2, in this example, raw coal was directly charged into a crusher 10, subjected to low reflux crushing, and then crushed. It is introduced into the container 12 and classified in multiple stages to obtain a classifier with a narrow particle size range.Other 4'+'7j
The configuration is the same as in Example 1.

Effects of the Invention Since the present invention is constructed with a diameter of 1″1τ as described above, it has the following effects.

(1) Instead of using an excessive amount of coal as in the past, it is possible to reduce the power cost significantly by using a minimum amount of low flow rate (j4b).

(2) By carrying out low-J flow crushing, the ash content in the coal is concentrated in a certain particle size fraction, and a deashing effect can be expected depending on the particle size distribution of the product amount.

(3) The coal obtained by the present invention has uniform particles in each particle size range, and the combustion speed is almost the same, so a uniform burn-out time can be obtained, achieving high combustion efficiency and a combustion efficiency comparable to that of oil. Highly controlled students can achieve this. It can also be applied to small boilers with an evaporation rate of around 10 t/h, where it is difficult to increase combustion efficiency with 1ffl, expanding the possibility of switching fuel to coal.

(4) The present invention enables the supply of fuel that can provide optimal combustion conditions to boilers of various sizes existing within an economical transportation area through seedling processing of coal at a call center, etc., and improves combustion efficiency. It is possible to improve fuel efficiency and switch to coal as a fuel.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing an example of an apparatus for implementing the method for producing coal burner 1 of the present invention, and FIG. 2 is a flow sheet showing another example of an apparatus for carrying out the method of the present invention. Figure 3 shows raw coal, secondary crushed coal, - secondary products, secondary products, tertiary products,
A graph showing the particle size groove bottom of the quaternary product, and FIG. 4 is a graph showing the relationship between particle size and ash content.

Claims (1)

[Claims] 1. A method for producing coal fuel, which comprises pulverizing coal, then classifying the pulverized coal in multiple stages to obtain classified coal with a narrow particle size range, and making each classified coal into a product. 2 Coarsely pulverize coal to obtain coarse granulated coal and coarse pulverized coal, adjust the particle size of this coarse granulated coal to make a product, and after pulverizing the coarse pulverized coal,
Finely pulverized coal is classified in multiple stages to produce classified coal with a narrow roughness range.
A method for producing coal fuel, characterized in that each classified coal is used as a product. 3. The method for producing coal fuel according to claim 1 or 2, wherein the coal fuel is pulverized to a particle size of 0.3 mm or less. 4. The method for producing coal fuel according to claim 1 or 2, wherein the coal is classified into pulverized coal and ultra-fine coal having three or more types of particle size configurations. 5. The method for producing coal fuel according to claim 1 or 2, wherein the classification point is set according to the purpose of use.