KR101092402B1 - Removal system of moisture in coal and removal method thereof - Google Patents

Abstract

PURPOSE: A system and a method for removing moisture from coal are provided to prevent imperfect combustion caused by moisture of coal by employing an air-gap breaking drying method. CONSTITUTION: A system for removing moisture from coal comprises a crusher(1), a temperature controller(5), a cyclone(2), a bag filter(3), a coal powder reservoir(4), a hot air injection device, and an exhaust air collector(23). The crusher mixes moisture-containing coal and air and pulverizes the coal into powder. The temperature controller controls the temperature of the coal and air mixture discharged from the crusher. The cyclone divides the temperature-controlled mixture into the coal powder and the air. The bag filter collects the coal powder contained in the air separated by the cyclone. The coal powder reservoir stores the coal powder collected from the cyclone and the bag filter. The hot air injection device blows hot air to the coal powder reservoir in order to prevent moisture from infiltrating into the coal powder reservoir. The exhaust air collector implements heat exchange between combustion air and water with the exhaust air exhausted from the bag filter.

Description

Coal water removal system and its removal method {REMOVAL SYSTEM OF MOISTURE IN COAL AND REMOVAL METHOD THEREOF}

The present invention relates to a coal moisture removal system and a method of removing the same, and more particularly, in the grinding and conveying process by mixing coal with air at a temperature higher than room temperature so that coal can be effectively combusted in a combustion furnace. By maximizing the contact area between the large fine coal and hot air, the moisture in the coal is temporarily transferred to the hot air, and then forcedly separating the fine powder of coal and the wet air containing the moisture, thereby effectively and economically separating the moisture contained in the coal. It is to remove.

In general, large-capacity coal-fired boilers (burning furnaces) mostly use bituminous coal and anthracite coal, and sometimes a mixture of bituminous coal and lignite is mixed with bituminous coal.

The classification of the coal species is divided according to the degree of carbonization, the greater the degree of carbonization is divided into lignite, sub-bituminous coal, bituminous coal, anthracite coal. That is, the largest carbon is anthracite and the smallest is lignite. In general, as the carbonization progresses, the calorific value increases and the moisture decreases. As the carbonization progresses, the internal pores become smaller and the moisture content decreases. As a result, bituminous coal and anthracite coal have a higher unit calorific value than lignite and sub-bituminous coal.

Therefore, the coal-fired boiler mainly uses bituminous coal and anthracite coal, which have a high calorific value and good thermal power. However, anthracite coal lacks a volatile component having good combustibility. Most preferred.

For this reason, coal demand is concentrated on bituminous coal, and lignite, which accounts for 45% of coal reserves, and a substantial amount of sub-bituminous coal are not used. As described above, the distortion of coal use not only widened the price difference between lignite and bituminous coal in the world, but also acts as a cause of shortage of bituminous coal compared to the rich lignite reserves.

In addition, when describing coal moisture, which is classified as the biggest cause of combustion disturbance in coal combustion process, the moisture content in coal varies greatly depending on the degree of carbonization, but is generally in the range of about 5 to 40% by weight. have. Here, the water content of coal tends to decrease as the carbonization progresses, so the anthracite coal having the most carbonization is about 10% by weight or less, and the relatively low carbonized lignite contains up to about 40% by weight. As described above, the reason why a large amount of water is present in coal is that the formation of coal indicates that water is contained in numerous pores generated as gaseous substances escape during the coalification process in which organic matter is subjected to high temperature and pressure. Can be. Therefore, lignite and sub-bituminous coal, which have undergone less coalification, contain about 40% by weight of water, which is about half the weight. On the contrary, bituminous coals and anthracite coals, which are relatively more carbonized, are exposed to high temperatures and pressures, so that the space in the coal is reduced due to the compression and destruction of the pores.

The problem of moisture contained in coal as described above is that the moisture itself does not produce calories, but rather it is converted into high temperature steam through the evaporation process by the heat of coal in the combustion furnace and is discharged to the atmosphere with exhaust gas. In addition to causing exhaust gas loss including latent heat of evaporation, high moisture coal is difficult to use because high heat coal decreases the heat content per unit weight and causes the combustion chamber temperature to be lowered in the combustion furnace requiring high temperature. In particular, the moisture contained in coal increases by several thousand times in volume during the phase transition from the liquid phase to the gaseous phase in the combustion furnace, resulting in reduced oxygen concentration per unit volume in the combustion chamber and lowering the residence time of the combustion air. Causing incomplete combustion of the gas, causing it to lead to energy loss, and also exhaust gas Increasing combustion provides an unreasonable load on the capacity of auxiliary equipment, and the water content of coal is known to be the biggest cause of combustion disturbances in the use of coal as fuel.

In order to remove moisture in the coal, the combustion site attempts to dry by loading hot air from the bottom of the bunker after loading coal containing moisture into the coal bunker (storage tank), but it is difficult to remove the moisture present in the numerous pores of the coal. Since coal particles are relatively large (about 1 to 50mm), even if hot air is applied, most of them cannot be contacted with moisture present in the pores of coal particles, so it is difficult to remove moisture effectively, and it takes a long time to dry and a large amount of energy. In reality, field application is difficult. In addition to the technical problems of coal drying, another problem of coal drying is a problem of aeration speed through which hot air required for drying into the coal pile passes. It is true that coal containing moisture has a relatively heavy weight of 1.5 to 1.8, and it is difficult to effectively dry because it is difficult to pass the hot air required for drying into the heavy coal pile.

Therefore, the development of a technology that economically and effectively removes moisture of coal, which acts as a big obstacle to coal combustion, is urgent and urgent.

Therefore, the present invention has been proposed to improve the above problems, in order to effectively remove the water that is difficult to remove in the pore of coal, the coal is crushed to destroy the pore and at the same time to increase the specific surface area and mix the hot air By maximizing the contact effect between the moisture in the coal and the high temperature air in the stirring, conveying, and separating process to facilitate the movement of moisture into the air, the moisture contained in the coal is effectively reduced by forcibly separating and removing the air with high moisture content. It is an object of the present invention to provide a coal moisture removal system and a method of removing the same.

In order to achieve the above object, the present invention comprises a pulverizer for mixing the coal containing water and air and grinding the coal into fine powder; A temperature controller for controlling the temperature of the mixture of fine coal powder and air discharged from the mill; A cyclone for separating the mixture whose temperature is controlled by the temperature controller into coal fine powder and air; A bag filter for collecting coal fine powder contained in air separated from the cyclone; A coal fine powder storage tank for storing the coal fine powder collected by the cyclone and the bag filter; a hot air injecting device for blowing hot air into the coal fine powder storage tank to prevent re-inflow of moisture from the coal fine powder storage tank; It provides a coal moisture removal system comprising an exhaust air heat recovery unit for respectively heat-exchanging combustion air and water with the exhaust air discharged from the bag filter.

The apparatus may further include a grinder air blower for injecting air into the grinder and a grinder air heater for heating the air injected into the grinder.

The hot air injection device, an air blower for coal fine powder storage tank for injecting air into the coal fine powder storage tank, an air heater for coal fine powder storage tank for heating air injected into the coal fine powder storage tank, and air for the coal fine powder storage tank It characterized in that it comprises a coal fine powder storage tank hot air injection pipe for injecting air heated by a heater into the coal fine powder storage tank.

The apparatus may further include a bag filter discharge blower configured to discharge the discharged air passing through the cyclone through the bag filter to the atmosphere.

The exhaust air heat recovery unit may include a combustion air heat exchanger for exchanging combustion air and exhaust air discharged from the bag filter, and a water heat exchanger for exchanging water and exhaust air discharged from the bag filter.

A combustion air blower that blows air from the bag filter to the combustion furnace air supply pipe through which the combustion air heat exchanged in the exhaust air heat recovery unit flows, and combustion air flowing through the combustion furnace air supply pipe to the combustion furnace. It may further include.

And a coal injector for injecting moisture-containing coal into the mill; A mill air inlet tube for injecting air into the mill; A mixture conveying tube through which a mixture of pulverized coal fine powder and air is conveyed; A cyclone extraction air transfer pipe for transferring the air separated from the cyclone to the bag filter; A bag filter discharge pipe through which air discharged from the bag filter flows; A first feed pipe for storing coal fine powder, wherein the coal fine powder separated from the cyclone is transferred to the coal fine powder storage tank; A second transfer pipe for storing fine coal powder, wherein the fine coal powder collected by the bag filter is transferred to the fine coal storage tank; A first feed pipe for injecting coal fine powder combustion furnace for transferring coal fine powder separated from the cyclone to a combustion furnace; A second transfer pipe for injecting coal fine powder combustion furnace for transferring coal fine powder collected by the bag filter to the combustion furnace; A third transfer pipe for injecting coal fine powder combustion furnace for transferring coal fine powder of the coal fine powder storage tank to the combustion furnace; A coal fine powder storage tank air discharge pipe discharged from the coal fine powder storage tank to the bag filter; And a condensate recovery tube for recovering the condensed water condensed in the discharge air heat recovery unit to a condensate storage tank.

On the other hand, according to another field of the present invention, the object, the step of mixing the coal containing water and air, and pulverizing the coal into fine powder; Transferring the mixture of fine coal powder and air discharged from the grinder to a cyclone; Adjusting the temperature of the mixture to be transferred to the cyclone; Separating the coal fine powder and air by forming a vortex in the cyclone mixture mixture transferred to the cyclone; Filtering fine coal powder contained in air discharged from the cyclone in a bag filter; It is also achieved by the coal moisture removal method comprising the step of recovering heat from the discharged air discharged from the bag filter to the atmosphere.

Here, the method may further include blowing hot air into the coal fine powder storage tank and discharging the hot air injected into the coal fine powder storage tank through a coal fine powder storage tank air discharge pipe.

The temperature of the air injected into the grinder is characterized in that less than 250 ℃.

The powder degree of coal pulverized in the crusher is characterized in that it further comprises a 5,000cm2 / g or less.

According to the present invention, by adopting the forced-pore-drying method as described above, it is possible to completely solve the combustion disturbance caused by the moisture of the coal, so that the use of coal and sub-bituminous coal with abundant reserves and low cost is possible. Efficient use as well as economical operation of the combustion furnace can be achieved by securing an inexpensive energy source, and it is not only possible to solve the problem of excessive load on the flue gas loss due to the coal moisture and the auxiliary equipment of the combustion furnace, but also to improve the drying speed. With the increase in the size of drying facilities, productivity improvement, and significant economic feasibility, the application of the field can be realized, which will enable the company to cope with the competition for securing energy resources in the future.

1 is a block diagram of a coal moisture removal system according to the present invention.

Hereinafter, the present invention will be described in detail.

In the present invention, the coal containing moisture is introduced into the grinder 1 using the coal injector 11, and the air is simultaneously injected into the grinder 1 using the grinder air inlet tube 12, and coal and air After the mixture is pulverized, the powdered coal is sufficiently stirred with the injected air, and then the coal fine powder and the mixture of air are transferred to the cyclone (2) through the mixture conveying pipe (13), so that the fine coal powder is lowered. After collecting and separating the air to the upper portion, the air separated to the upper portion is transferred to the bag filter (3) through the cyclone extraction air transfer pipe (14), and the coal fine powder separated into the lower portion is the first for storing coal fine powder. Transfer to the coal fine powder storage tank (4) by the transfer pipe (16), or through the first feed pipe (18) for coal fine powder combustion furnace injection into the combustion air supply pipe (29) directly put into the combustion furnace, the bag Cyclone (2) extraction hole transferred to filter (3) The fine air finely filtered fine coal powder is recovered by the bag filter discharge blower 10 to the atmosphere or stack through the bag filter discharge pipe 15 to recover the heat and moisture of the discharged air, and is filtered out of the bag filter (3) The coal fine powder collected in the lower hopper is transferred to the coal fine powder storage tank 4 through the second transfer pipe 17 for storing the fine coal powder, or the combustion air supply pipe through the second transfer pipe 19 for the coal fine powder combustion ( 29) can be directly blown into the combustion furnace, and the coal fine powder stored in the coal fine powder storage tank (4) can also be directly blown into the combustion furnace through the third feed pipe (20) for coal fine powder combustion furnace injection. Coal moisture removal system.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block diagram of a coal moisture removal system according to the present invention. As shown in FIG. 1, the coal containing the water is pulverized by entering the grinder 1 with a coal injector 11. At this time, air is simultaneously blown into the grinder 1 using the grinder air injection pipe 12. Here, the air blown into the grinder 1 is blown by the air blower 8 for the grinder, but is heated by blowing the temperature with the air heater 6 for the grinder. The reason for heating the air is to absorb a lot of moisture into the air while in contact with the powdered coal particles in the mill (1). This theoretical basis implies that the amount of saturated steam increases as the temperature of the air increases, so that the amount of water vapor that can be contained in the air increases as the temperature increases. The following table shows the amount of saturated steam by temperature.

Here, the saturated steam amount refers to the weight of the maximum amount of steam that can enter 1 m 3 of air, and as the temperature increases, the saturated steam amount can be seen to increase. This means that the maximum amount of steam that can be absorbed by 1㎥ of air at a temperature of 30 ℃ close to room temperature is 30.4g, compared to 30.4g. It can be included. In other words, the warmer the air, the greater the capacity to hold water vapor. However, the more the air is heated, the greater the amount of saturated steam can take away the moisture contained in the coal.However, if the temperature rises above 250 ° C, the volatilization of coal volatilizes and the volatilized material ignites, resulting in a fire accident. It is preferable to warm the temperature to 250 degrees C or less. At this time, the reference point of the temperature is the temperature of the coal fine powder and the air mixture measured at the inlet of the cyclone (2).

The reason for crushing the coal is to destroy the voids in the coal and increase the specific surface area. As described above, coal has a myriad of pores generated during the carbonization of organic matter. Due to the presence of moisture in the pores, even though the hot air is vented between the coal particles, only the surface drying proceeds in contact with the outer surface of the coal. The size of these internal pores can be inferred from the sum of the moisture content of lignite at about 40% by weight, the sum of all the pores in the coal accounting for about 40% of the coal. In addition, general coal particles have a size of about 1 to 50 mm and it is difficult to remove moisture from relatively large coals. This is because the rate increases, and the specific surface area decreases, thereby reducing the hot air and the contact area.

As described above, general coal having a relatively large particle and a low powder is not only a reason for the excessive porosity, the moisture present in the position deep from the particle surface, and the low specific surface area, which is difficult to dry. It is also difficult to vent the coal, so that coal is crushed to destroy pores, finely divided particles to increase specific surface area, disperse coal in fine powder in warm air, and fluidize it primarily to increase the specific surface area of coal. Maximizes the contact area with water, and secondly, breaks the voids to directly contact water with the hot air, and thirdly distributes the hot water evenly in the hot air to ensure sufficient contact with the hot air as a medium for transport and separation. In the warmed air with high content, coal moisture quickly Which it will be transferred.

Herein, the pulverization of coal is preferably pulverized to 5,000 cm 2 / g in consideration of the combustibility and economical cost of the pulverization. When coal is excessively increased in consideration of moisture drying, the combustibility may be too high, leading to explosive combustion in the combustion process, and excessive grinding cost is the reason for limiting the powder degree. When the powder degree is increased as described above, the specific surface area is increased by several hundred times when the general coal powder degree is about 10-15 cm 2 / g, which leads to an increase in the drying speed of several hundred times during the contact with hot air.

The mixture of the heated hot air and the pulverized coal fine powder as described above is transferred to the cyclone 2 through the mixture feed pipe 13. At this time, the temperature controller 5 controls the temperature of the mixture of fine coal powder and air discharged from the grinder 1 with the temperature controller 5, the measuring point of the temperature control is the inlet of the cyclone (2) and the control temperature is 250 ℃ Let it be as follows.

In addition, the effect of inducing contact and collision between the two mixtures is effectively added while the mixture is transferred through the mixture feed pipe 13.

The mixture conveyed to the cyclone 2 is forcibly separated into solid coal fine powder at the bottom and gaseous air at the top. At this time, the air separated into the upper part is a relatively hot air, in which a large amount of wet and fine coal dust is mixed with a large amount of moisture in coal, and the solid coal fine powder separated into the lower part has been transferred to high temperature air. It is dried.

Here, the process of separating the mixture in the cyclone (2) is when the fine coal powder is dispersed in hot air and applied to the cyclone (2) while forming a strong vortex from the inlet of the cyclone (2) while the mixture according to the centrifugal force and gravity The particles are separated by their own weight. The strong vortex generated in the separation process reaches the highest point of contact and collision between the fine coal powder and the hot air to induce the maximum absorption of the hot air in the vaporized unsaturated state, and then forcibly extracts the air. By removing it, maximization of the drying efficiency can be achieved.

The dried coal fine powder separated into the cyclone (2) is transferred to the coal fine powder storage tank (4) using the first feed pipe (16) for storing the fine coal, or the first feed pipe for injection of the fine coal combustion furnace ( 18) is injected into the combustion air supply pipe 29 and blown directly into the combustion furnace together with the combustion air. At this time, the combustion air absorbs the heat in the exhaust air by using the combustion air heat exchanger 26 in the exhaust air heat recovery unit 23 and then the combustion air supply pipe 29 to the combustion air blower 30. Blow into the furnace. In addition, the hot humid air separated to the upper part is transferred to the bag filter (3) by the cyclone extraction air transfer pipe (14), and fine coal fine powder is collected in the bag filter (3) hopper after filtration, and the second transfer for storing coal fine powder is carried out. Transfer to the coal fine powder storage tank (4) to the tube (17) or through the second feed pipe (19) for coal fine powder combustion furnace injection into the combustion air supply pipe (29) and blows directly to the combustion furnace with the air for combustion Put it in. In addition, the humid air which has been cleaned after filtration is discharged to the atmosphere or the stack through the bag filter discharge pipe 15 by the bag filter discharge blower 10.

At this time, heat and condensed water in the discharged air are immediately recovered before being discharged from the discharged air heat recoverer 23. The exhaust air heat recovery unit 23 heat exchanges the exhaust air discharged from the water and the bag filter 3 with the combustion air heat exchanger 26 for exchanging the combustion air and the exhaust air discharged from the bag filter 3. A water heat exchanger (27). Accordingly, the combustion air heat exchanger 26 is used to recover heat to combustion air to increase combustion furnace efficiency, and the water is transferred to water stored in the water storage tank 24 using the water heat exchanger 27. It can contribute to the recovery of thermal energy, such as steam and hot water production, and additionally condensed water condensed in the heat recovery process can be recovered as a condensate storage tank 25 using the condensate recovery pipe 28 can be utilized as industrial water.

In addition, the dry coal fine powder transferred from the cyclone (2) lower part and the bag filter (3) hopper stored in the coal fine powder storage tank (4) is introduced into the combustion furnace using the third feed pipe (20) for coal fine powder combustion furnace injection. To burn.

Here, in order to prevent the inflow of moisture to the dry coal fine powder stored in the coal fine powder storage tank 4 is provided with a hot air injector for blowing hot air to the coal fine powder storage tank (4). The hot air injection device includes an air blower 9 for coal fine powder storage tank for injecting air into the coal fine powder storage tank 4 and an air heater 7 for coal fine powder storage tank for heating air injected into the coal fine powder storage tank 4. And a coal fine powder storage tank hot air injection pipe 21 for injecting air heated by the air heater 7 for the coal fine powder storage tank into the coal fine powder storage tank 4. Thus, the coal fine powder storage tank injection air blower (9) through the coal fine powder storage tank hot air injection pipe (21) is heated to the coal fine powder storage tank injection air heater (7) to blow into the coal fine powder storage tank (4), coal fine powder The reservoir air discharge pipe 22 is used to discharge the bag filter 3.

As described above, the coal containing moisture destroys the voids and increases the specific surface area and then makes contact with hot air, thereby increasing the contact area by tens to hundreds of times as well as the direct contact with hot water. By transferring the air to the air and then forcibly separating the solid coal fine powder and the gaseous air and removing the separated wet air, thereby improving the drying efficiency and shortening the drying time. It is a breakthrough technology that can make full use of energy resources.

It is apparent to those skilled in the art that the present invention is not limited to the embodiments described and that various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, such modifications or variations will have to be belong to the claims of the present invention.

1: grinder
2: cyclone
3: bag filter
4: coal fine powder storage tank
5: thermostat
6: air heater for grinder
7: Air heater for injection of coal fine reservoir
8: Air blower for grinder
9: Air blower for injection of coal fine reservoir
10: bag filter exhaust blower
11: coal injector
12: grinder air injection tube
13: mixture conveying tube
14: cyclone extraction air transfer pipe
15: bag filter discharge pipe
16: 1st transfer pipe for coal fine powder storage
17: Second conveying pipe for storing coal fine powder
18: first feed pipe for injection of coal fine powder combustion
19: second conveying pipe for injection of coal fine powder combustion furnace
20: third transfer pipe for injection of coal fine powder combustion furnace
21: coal fine powder storage tank hot air injection pipe
22: coal fine powder reservoir air discharge pipe
23: exhaust air heat recovery machine
24: water reservoir
25: condensate reservoir
26: combustion air heat exchanger
27: water heat exchanger
28: condensate return pipe
29: combustion air supply pipe
30: combustion air blower

Claims (11)

A pulverizer for mixing water containing coal and air and grinding the coal into fine powder;
A temperature controller for controlling the temperature of the mixture of fine coal powder and air discharged from the mill;
A cyclone for separating the mixture whose temperature is controlled by the temperature controller into coal fine powder and air;
A bag filter for collecting coal fine powder contained in air separated from the cyclone;
A coal fine powder storage tank storing coal fine powder collected in the cyclone and the bag filter:
A hot air injector for blowing hot air into the coal fine powder storage tank to prevent inflow of moisture from the coal fine powder storage tank;
And a discharge air heat recovery unit configured to heat-exchange combustion air and water with discharge air discharged from the bag filter. The method of claim 1,
An air blower for a grinder for injecting air into the grinder;
And a grinder air heater for heating the air injected into the grinder. The method of claim 1,
The hot air injector,
An air blower for coal fine powder storage tank for injecting air into the coal fine powder storage tank,
An air heater for coal fine powder storage tank for heating air injected into the coal fine powder storage tank;
Coal fine powder storage tank hot air injection pipe for injecting the air heated by the air heater for the coal fine powder storage tank into the coal fine powder storage tank. The method of claim 1,
And a bag filter exhaust blower for exhausting the exhaust air passing through the cyclone through the bag filter to the atmosphere. The method of claim 1,
The discharge air heat recovery unit,
A combustion air heat exchanger for exchanging combustion air and exhaust air discharged from the bag filter;
And a water heat exchanger for heat-exchanging water and exhaust air discharged from the bag filter. The method of claim 1,
A combustion furnace air supply pipe through which air discharged from the bag filter and combustion air heat exchanged in the exhaust air heat recovery unit flow;
And a combustion air blower for blowing the combustion air flowing through the combustion furnace air supply pipe to the combustion furnace. The method of claim 1,
A coal injector for injecting moisture-containing coal into the mill;
A mill air inlet tube for injecting air into the mill;
A mixture conveying tube through which a mixture of pulverized coal fine powder and air is conveyed;
A cyclone extraction air transfer pipe for transferring the air separated from the cyclone to the bag filter;
A bag filter discharge pipe through which air discharged from the bag filter flows;
A first feed pipe for storing coal fine powder, wherein the coal fine powder separated from the cyclone is transferred to the coal fine powder storage tank;
A second transfer pipe for storing fine coal powder, wherein the fine coal powder collected by the bag filter is transferred to the fine coal storage tank;
A first feed pipe for injecting coal fine powder combustion furnace for transferring coal fine powder separated from the cyclone to a combustion furnace;
A second transfer pipe for injecting coal fine powder combustion furnace for transferring coal fine powder collected by the bag filter to the combustion furnace;
A third transfer pipe for injecting coal fine powder combustion furnace for transferring coal fine powder of the coal fine powder storage tank to the combustion furnace;
A coal fine powder storage tank air discharge pipe discharged from the coal fine powder storage tank to the bag filter;
And a condensate recovery tube for recovering the condensed water condensed in the exhaust air heat recovery unit to a condensate storage tank. Mixing water containing coal and air, and grinding the coal into fine powder;
Transferring the mixture of fine coal powder and air discharged from the grinder to a cyclone;
Adjusting the temperature of the mixture to be transferred to the cyclone;
Separating the coal fine powder and air by forming a vortex in the cyclone mixture mixture transferred to the cyclone;
Filtering fine coal powder contained in air discharged from the cyclone in a bag filter;
And recovering heat from the discharged air discharged from the bag filter and discharging it to the atmosphere. The method of claim 8,
Blowing hot air into the coal fine powder storage tank;
And discharging hot air injected into the coal fine powder storage tank through a coal fine powder storage air discharge pipe. The method of claim 8,
The temperature of the mixture is transferred to the cyclone, characterized in that the coal moisture removal method characterized in that less than 250 ℃ measured at the cyclone inlet. The method of claim 8,
Coal pulverization in the pulverizer Coal water removal method characterized in that it further comprises a 5,000cm2 / g or less.

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