JP2012145281A - Method and system for drying lignite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for drying lignite that utilizes the spontaneous combustion of the lignite to dry the lignite without being supplied with thermal energy from the external.SOLUTION: The system includes: a container 2 into which the lignite 1 being a dry target is put; an agitator 4 for agitating the lignite 1 put into the container 2; a supply conduit 8 for supplying air into the container 2; a humidity measuring instrument 16 for measuring humidity of exhaust gas discharged from the container 2; and a controller 17 for controlling any one of at least an agitation speed, an air supply amount, or temperature of supplied air via the agitator 4 or the supply conduit 8, until the humidity measured by the humidity measuring instrument 16 reaches a predetermined value.

Description

  The present invention relates to a drying method and a drying system of lignite, and is particularly useful when applied to the drying of lignite using natural heat generation.

  Since lignite contains a large amount of moisture, even if it is crushed and burned to a particle size that can be used as boiler fuel as it is, heat loss due to moisture in the combustion gas combusted in the boiler furnace ( (Latent heat) increases, and there is a problem that the thermal efficiency of the whole plant is lowered. For this reason, lignite is classified as low-grade coal along with sub-bituminous coal whose water content exceeds about 20 mass%.

  On the other hand, lignite has the same reserves as bituminous coal, which is regarded as high-grade coal, and is low in price and contains a lot of low sulfur. Use as a fuel has been proposed (see, for example, Patent Document 1). The power generation plan disclosed in Patent Document 1 aims to improve the thermal efficiency of the entire plant by efficiently drying low-grade coal as a fuel, and has a particle size that can be used as fuel for a boiler. The low-grade coal that has been pulverized to a minimum is dried with a drying system. Here, the drying system uses air heated by using the exhaust heat of the power plant as a heat source.

JP 2010-223572 A

For example, as disclosed in Patent Document 1 described above, it is necessary to separately supply thermal energy for drying to dry low-grade coal according to the prior art. Therefore, such heat energy is wasted and there is room for further improvement. On the other hand, in the case of lignite, it has the property of spontaneously generating heat by a chemical reaction with oxygen in the air.

  An object of this invention is to provide the drying method and drying system of lignite which dries lignite without supplying heat energy from the outside using the natural exothermic property of lignite in view of the said prior art.

  The first aspect of the present invention that achieves the above object is to supply air while stirring the lignite in a container charged with the lignite that is to be dried, so that the lignite is naturally heated and discharged from the container. In the method for drying lignite, the lignite is dried by heat accompanying the spontaneous heat generation until the humidity of the exhaust gas reaches a predetermined value.

  According to this aspect, the lignite can be satisfactorily dried using the heat of its natural heat generation, using the humidity of the exhaust gas discharged from the container into which the lignite is charged and dried.

  In the second aspect of the present invention, the lignite is supplied with air while stirring the lignite in a container charged with the lignite to be dried, and the lignite is naturally heated, and is discharged from the container accompanying the spontaneous heat. Drying characteristics representing the relationship between the temperature of the exhaust gas and the degree of drying of the lignite using at least one of the stirring speed, the air supply amount or the temperature of the supply air as a parameter And drying the lignite by raising the temperature until the exhaust gas reaches a predetermined temperature.

  According to this aspect, the lignite can be satisfactorily dried using the heat of the natural heat generated by using the temperature of the exhaust gas discharged from the container into which the lignite is charged and dried.

  In the third aspect of the present invention, the lignite is supplied with air while stirring the lignite in a container charged with the lignite to be dried, and the lignite is naturally heated, and is discharged from the container accompanying the spontaneous heat. The concentration of the specific gas in the exhaust gas is measured, and the concentration of the specific gas using at least one of the stirring speed, the air supply amount or the temperature of the supply air as a parameter and the degree of drying of the lignite The drying method of lignite is characterized in that the lignite is dried by raising the temperature until the specific gas has a predetermined concentration based on the drying characteristics representing the above relationship.

  According to this aspect, the lignite can be satisfactorily dried using the heat of its natural heat generation by using the concentration of the specific gas in the exhaust gas discharged from the container to which lignite is charged and dried.

  According to a fourth aspect of the present invention, in the method for drying lignite according to any one of the first to third aspects, the lignite dried from the container when the predetermined humidity, temperature, or concentration is reached. In the drying method of lignite characterized by supplying new lignite.

  According to this aspect, the drying process of lignite can be performed continuously.

  According to a fifth aspect of the present invention, there are provided a container into which lignite to be dried is charged, a stirring means for stirring the lignite charged in the container, an air supply means for supplying air into the container, Humidity measuring means for measuring the humidity of exhaust gas discharged from the container, and at least the stirring speed and air through the stirring means or the air supply system until the humidity measured by the humidity measuring means reaches a predetermined value And a control means for controlling any one of a supply amount and a temperature of supply air.

  According to this aspect, the lignite is heated using the heat of its natural heat generation by controlling the stirring speed, the amount of air supply or the temperature of the supply air, etc., with the humidity of the exhaust gas discharged from the container to which lignite is charged and dried. Can be dried well.

  According to a sixth aspect of the present invention, there is provided a container into which brown coal to be dried is charged, a stirring means for stirring the brown coal charged into the container, an air supply means for supplying air into the container, A temperature measuring means for measuring the temperature of the exhaust gas discharged from the container, and the temperature of the exhaust gas and the drying of the lignite using at least one of the stirring speed, the air supply amount or the temperature of the supply air as parameters Any one of at least the stirring speed, the air supply amount, and the air temperature through the stirring means or the air supply system until the temperature of the exhaust gas reaches a predetermined value based on the drying characteristics representing the relationship with the degree of And a lignite drying system characterized by having a control means for controlling one of them.

  According to this aspect, the heat of the natural heat generated from the lignite is controlled by controlling the stirring speed, the amount of air supplied or the temperature of the supplied air, etc., using the temperature of the exhaust gas discharged from the container to which the lignite is charged and dried. Can be dried well.

  According to a seventh aspect of the present invention, there is provided a container in which lignite to be dried is charged, a stirring means for stirring the lignite charged in the container, an air supply means for supplying air into the container, Concentration measuring means for measuring the concentration of the specific gas in the exhaust gas discharged from the container, and the specific gas having at least one of the stirring speed, the air supply amount, or the temperature of the supply air as a parameter Based on the drying characteristics representing the relationship between the concentration and the degree of drying of the lignite, until the concentration of the specific gas reaches a predetermined value, at least the stirring speed, the air supply amount, or the air supply system through the stirring means or the air supply system And a control means for controlling any one of the temperatures of the air.

  According to this aspect, the natural heat generation of lignite is controlled by controlling the stirring speed, the amount of air supplied, or the temperature of the supplied air, etc., using the concentration of the specific gas in the exhaust gas discharged from the container to which lignite is charged and dried. It can be dried satisfactorily using the heat of.

  The eighth aspect of the present invention is the lignite drying system according to any one of the fifth to seventh aspects, further comprising heating means for heating the lignite in the container. In the system.

  According to this aspect, it is possible to provide a trigger for spontaneous heat generation and smoothly start desired heat generation. At the same time, the heat in the container generated by the spontaneous heat generation of the lignite can be prevented from escaping to the outside, and the predetermined drying process can be performed efficiently.

  According to a ninth aspect of the present invention, in the lignite drying system according to the eighth aspect, the heating means is formed by a heating part of a heat pump, and a cooling / heating part of the heat pump is formed between the air supply means and the container. In the drying system for lignite, the air supplied to the container is arranged to be cooled and dehumidified.

  According to this aspect, in addition to the action and effect of the eighth aspect, dry air with reduced humidity can be supplied into the container, and therefore, it can contribute to efficient drying of lignite.

  According to a tenth aspect of the present invention, in the lignite drying system described in the ninth aspect, the heating unit is also disposed in the air supply system between the cold heat unit and the container. It is in the drying system of lignite.

  According to this aspect, in addition to the action and effect of the eighth aspect, dry air with reduced humidity can be further heated and supplied into the container, which contributes to more efficient drying of lignite. Can do.

  According to an eleventh aspect of the present invention, in the lignite drying system according to any one of the fifth to tenth aspects, the exhaust gas discharged from the container and the air supply system pass through the container. In the lignite drying system, a heat exchanger for exchanging heat with the air supplied to the air is disposed in the air supply system.

  According to this aspect, the heat energy which the exhaust gas which absorbed the heat | fever generate | occur | produced by the natural heat_generation | fever of lignite in a container can be given to supply air through heat exchange. As a result, supply air is heated and can contribute to efficient drying of lignite.

  According to a twelfth aspect of the present invention, in the brown coal drying system according to any one of the fifth to eleventh aspects, the apparatus further comprises nitrogen supply means for supplying nitrogen into the container. It is in the drying system of lignite.

  According to this aspect, the oxidation reaction of lignite can be suppressed by supplying nitrogen into the container. As a result, ignition and combustion of lignite can be prevented and a safe and good predetermined drying process can be performed.

  According to the present invention, the lignite is supplied with air while stirring the lignite in a container charged with the lignite, so that the lignite is naturally heated, and the humidity in the exhaust gas discharged from the container, the temperature of the exhaust gas, or the exhaust gas A physical quantity that is the concentration of a specific gas in the gas can be measured, and the degree of drying of the lignite can be specified based on each physical quantity. As a result, the lignite can be satisfactorily dried without separately supplying heat energy using the heat of spontaneous heat generated by the chemical reaction between the lignite and oxygen.

It is a block diagram which shows the drying system of the lignite which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the drying system of the lignite which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the drying system of the lignite which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the drying system of the lignite which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the drying system of the lignite which concerns on the 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram showing a first embodiment of the present invention. As shown in the figure, the container 2 for drying the lignite 1 forms a sealed space with a cylindrical member having a vertical axis in the figure in the case of this embodiment. The container 2 is provided with a mesh-like bottom plate 2A at the bottom, and the brown coal 1 placed on the bottom plate 2A is stirred by the stirring device 4. The stirring device 4 has a vertical rotating shaft 4A along the central axis of the container 2 and a plurality of blades 4B provided so as to protrude in the horizontal direction from the middle of the rotating shaft 4A, and rotates using the motor 3 as a driving source. The lignite 1 is stirred by the blade 4B by rotating the shaft 4A. The lignite 1 is put into the container 2 from the upper part through the lignite supply means 5. On the other hand, the lignite 1 that has been subjected to the predetermined drying process is discharged from the lower portion of the container 2 through the dried lignite discharging means 6.

  The air supply means 7 blows air for causing an oxidation reaction with the lignite 1 into the lignite 1 in the container 2 through the supply line 8 and the bottom plate 2A. This air supply means 7 can be suitably formed by a compressor, a blower or the like. A nitrogen supply means 9 is also connected to the supply pipe line 8, and in some cases, nitrogen gas can be blown into the lignite 1 in the container 2. Nitrogen gas is blown when the oxidation reaction of lignite 1 is forcibly stopped, which will be described in detail later. Here, the flow rate adjusting valves 10 and 11 are arranged in the middle of the pipe line corresponding to the air supply unit 7 and the nitrogen supply unit 9 and reach the inside of the container 2, and the flow rate adjustment valve 10 is normally open. Air via the supply line 8 is supplied into the container 2. On the other hand, in a predetermined emergency, the flow rate adjustment valve 11 is opened, and nitrogen is supplied into the container 2 through the supply line 8.

  Here, in the container 2, air whose supply amount and temperature are adjusted so that the brown coal 1 spontaneously generates heat by the oxidation reaction between the stirred brown coal 1 and air is supplied. The air heated by reacting with the lignite 1 is discharged to the outside through the exhaust pipe 12 as an exhaust gas together with the gas generated by the oxidation reaction between the lignite 1 and the air.

  The heating means 13 is disposed so as to surround the outer peripheral surface of the container 2, and heats the lignite 1 in the container 2. The heating means 13 functions as a trigger for smoothly starting the spontaneous heat generation of the lignite 1 and at the same time functions as a heat insulating portion for preventing the heat in the container 2 generated by the natural heat generation from escaping to the outside. . That is, the spontaneous exothermic reaction is more easily caused by making the temperature of the lignite 1 in the container 2 slightly higher than the environmental temperature (room temperature). Therefore, in this embodiment, the temperature of the lignite 1 in the container 2 is made slightly higher than the environmental temperature by heating by the heating means 13 so that the temperature rise due to natural heat generation can be performed smoothly, and once the natural heat generation reaction occurs. After being started, the heat generated by the spontaneous heating is prevented from being wasted to the environment without being used for drying the lignite 1. However, the heating means 13 is not always necessary in principle. This is because a spontaneously exothermic reaction can be caused sufficiently by adjusting the amount of air supplied to the container 2, the air temperature, and the like even when the heating means 13 is not heated.

  On the other hand, when the heating means 13 is provided as in the present embodiment, a trigger for spontaneously exothermic reaction of the lignite 1 can be provided to start desired exotherm smoothly, and at the same time, generated by the spontaneously exothermic reaction of the lignite 1 Thus, there is an effect that the heat in the container 2 can be prevented from escaping to the outside and a predetermined drying process can be efficiently performed. The heating means 13 can be suitably formed with, for example, an electric heater.

  The temperature measuring device 14 measures the temperature of the lignite 1 that generates heat by being supplied with air while being stirred in the container 2, and the temperature at a position representative of the temperature of the lignite 1 in the container 2 is measured. It is installed to measure. The temperature measuring instrument 14 can be suitably formed with a thermocouple thermometer. The measured data is sent to the control means 17.

  The temperature measuring instrument 15 and the humidity measuring instrument 16 measure the temperature and humidity of the exhaust gas flowing through the exhaust pipe 12. The measured temperature and humidity data are sent to the control means 17.

The control means 17 performs the following controls.
1) The end point of the drying process of lignite 1 is determined based on the humidity data measured by the humidity measuring device 16. That is, when the humidity of the exhaust gas flowing through the exhaust pipe line 12 falls below a predetermined threshold value, it is determined that the predetermined drying process of the lignite 1 by natural heat generation is completed, and necessary predetermined control is performed. For example, the dry lignite discharging means 6 is controlled to discharge the lignite 1 in the container 2 after the drying process, and the lignite 1 to be dried is supplied into the container 2 via the lignite supply means 5. To do. Here, the supply and discharge of the lignite 1 may be a batch process performed every time the drying process of a certain amount of the lignite 1 charged into the container 2 is completed, or the lower lignite 1 where the drying proceeds further is sequentially discharged. However, the continuous process which supplies the new lignite 1 from the upper part may be sufficient.

2) Based on the temperature data measured by the temperature measuring device 15, the end point of the lignite 1 drying process is determined. In this case, it is necessary to store in the control means 17 in advance the drying characteristics data which is a correlation between the temperature of the exhaust gas and the degree of drying of the lignite 1 using predetermined parameters. That is, the relationship between the exhaust gas temperature and the degree of drying of the lignite 1 using at least one of the stirring speed of the lignite 1 by the stirring means 4, the air supply amount or the temperature of the supply air as a parameter is detected in advance. . Thus, a predetermined drying process can be performed by raising the temperature of the lignite 1 until the exhaust gas reaches a predetermined temperature. Thus, although the dry state of the lignite 1 can be grasped by controlling the temperature of the exhaust gas, for example, it is necessary to prepare the drying characteristics of the lignite as described above in advance for each predetermined condition such as each kind of the lignite 1. Therefore, it takes more time than managing the humidity of the exhaust gas. For this reason, it only has significance as an auxiliary drying specifying means.

3) The drive of the motor 3 is controlled to control the stirring speed of the stirring device 4.

4) The opening degree of the flow rate adjusting valve 10 is adjusted, and the amount of supply air blown into the container 2 through the supply pipe 8 is controlled. At this time, the flow rate adjustment valve 11 is controlled to be in a closed state.

5) When the temperature in the container 2 detected by the temperature measuring instrument 14 exceeds a predetermined value, the flow rate adjusting valve 11 is opened and nitrogen is blown into the container 2 through the supply pipe 8 to forcibly stop the spontaneous heat generation. Let In this case, the predetermined value of the temperature in the container 2 is set to a temperature at which the lignite 1 can be prevented from proceeding to ignition and combustion beyond natural heat generation due to its oxidation reaction. At this time, the flow rate adjustment valve 10 is controlled to be in a closed state.

  According to this form, since air is supplied while stirring the lignite 1 in the container 2 into which the lignite 1 is charged, the lignite 1 naturally generates heat due to a chemical reaction with oxygen in the air. Drying of the lignite 1 proceeds by heat generated by such natural heat generation. Here, since the humidity in the exhaust gas discharged from the inside of the container 2 is measured, the degree of drying of the lignite 1 can be grasped via this humidity. As a result, the predetermined drying of the lignite 1 can be satisfactorily performed without supplying heat energy separately using the heat of spontaneous heat generated by the chemical reaction between the lignite 1 and oxygen.

<Second Embodiment>
FIG. 2 is a block diagram showing a second embodiment of the present invention. In the figure, the same parts as those in FIG. As shown in the figure, a gas concentration measuring device 21 is also disposed in the exhaust pipe 12. The gas concentration measuring device 21 measures the concentration of a specific gas in the exhaust gas flowing through the exhaust pipe 12 and sends the data to the control means 27. Here, as the specific gas, CO or CO _{2 that} is generated by a chemical reaction between the lignite 1 and air and increases in concentration as the lignite 1 is dried is suitable. However, also in this case, it is necessary to store in the control means 27 in advance the data of the drying characteristics that are the correlation between the concentration of the specific gas in the exhaust gas and the degree of drying of the lignite 1 using predetermined parameters. is there. That is, the relationship between the exhaust gas temperature and the degree of drying of the lignite 1 using at least one of the stirring speed of the lignite 1 by the stirring means 4, the air supply amount or the temperature of the supply air as a parameter is detected in advance. . Thus, a predetermined drying treatment can be performed by raising the temperature of the lignite 1 until the concentration of the specific gas in the exhaust gas reaches a predetermined concentration. As described above, the dry state of the lignite 1 can be grasped also by controlling the concentration of the specific gas in the exhaust gas, but the drying characteristics of the lignite 1 are prepared in advance as in the case of controlling the temperature of the exhaust gas. Therefore, it takes more time than managing the humidity of the exhaust gas. For this reason, it only has significance as an auxiliary drying specifying means.

<Third Embodiment>
FIG. 3 is a block diagram showing a third embodiment of the present invention. In the figure, the same parts as those in FIG. As shown in the figure, this embodiment is obtained by adding a bypass line 31 and a G / G heat exchange 32 to the embodiment shown in FIG. The bypass line 31 is branched from the exhaust line 12, reaches the G / G heat exchange 32, and forms an exhaust gas flow path that returns to the exhaust line 12 again. Here, the G / G heat exchange 32 is disposed in the supply line 12. Therefore, the heat energy of the exhaust gas heated by the lignite that is naturally generating heat in the container 2 and rising in temperature can be recovered by heat exchange with the supply air by the G / G heat exchange 32. As a result, the temperature of the supply air blown into the container 2 can be raised, and the drying process of the brown coal 1 can be promoted accordingly.

  In this embodiment, a part of the exhaust gas is circulated through the bypass pipe 31. However, the exhaust gas may be exchanged by the G / G heat exchange 32.

<Fourth embodiment>
FIG. 4 is a block diagram showing a fourth embodiment of the present invention. In the figure, the same parts as those in FIG. As shown in the figure, in the present embodiment, the heating means 13 in the embodiment shown in FIG. That is, the tank of the heating unit 41B is formed so as to surround the container 2 and is filled with a heat medium such as water or oil. Such a heat medium is heated by a heating medium supplied from the heat pump main body 41A. On the other hand, the cooling / heating part 41 </ b> C of the heat pump 41 is interposed in the middle of the supply pipe 8 and is configured to dehumidify the supply air blown into the container 2 through the supply pipe 8. That is, the supply air is cooled and dehumidified by exchanging heat between the cooling medium supplied from the heat pump body 41A and the tank of the cooling unit 41C. The drain generated as a result of dehumidification is discharged out of the tank.

  According to this embodiment, not only can the heating unit 41B have the same function as the heating means 13 in FIG. 1, but also the supply air can be dehumidified by the cooling / heating unit 41C. Inside, dry air can be blown. This can contribute to efficient drying of the lignite 1.

<Fifth embodiment>
FIG. 5 is a block diagram showing a fifth embodiment of the present invention. In the figure, the same parts as those in FIGS. 1 and 4 are denoted by the same reference numerals, and redundant description is omitted. As shown in the figure, the present embodiment is obtained by changing the structure of the heat pump 41 in the embodiment shown in FIG. That is, the heating medium 51B of the heat pump 51 according to the present embodiment is not only heated by the heating medium supplied from the heat pump main body 41A but also the lignite 1 in the container 2, and is disposed downstream of the cooling unit 41C in the supply pipe 8. The heat exchanger 52 is configured to function as a heat source. That is, the heating medium supplied from the heat pump main body 41A circulates not only between the heating unit 51B but also the heat exchanger 52.

  According to this embodiment, the air is dried by being dehumidified by the cooling unit 41C, but is heated by exchanging heat with the heating medium supplied from the heat pump main body 41A in the heat exchanger 52 in the heat exchanger 52. Therefore, it is possible to blow dry air having a higher temperature than in the case of the fourth embodiment into the container 2. As a result, it is possible to contribute to more efficient drying of the lignite 1.

  In each of the above embodiments, the container 2 is a vertical type, and the stirring device 4 rotates about the vertical axis. However, the present invention is not limited to this. The container may be a horizontal type, and the stirring device may be configured to rotate about a horizontal axis. In this case, lignite is supplied into the container from one side in the horizontal direction and discharged from the other side. Air is supplied so as to flow from the discharge side to the supply side.

  Further, the bypass line 31 and the G / G heat exchanger 32 shown in the third embodiment can be combined with the second, fourth, and fifth embodiments. The same operations and effects as those of the third embodiment can also be obtained. Similarly, the second embodiment can be combined with the fourth and fifth embodiments, and when combined, the same operations and effects as the fourth and fifth embodiments can be obtained. it can.

  The present invention can be effectively used in the industrial field in which lignite is used as a fuel, for example, thermal power generation is performed.

DESCRIPTION OF SYMBOLS 1 Brown coal 2 Container 4 Stirrer 5 Brown coal supply means 6 Dry lignite discharge means 7 Air supply means 8 Supply line 9 Nitrogen supply means 12 Exhaust line 13 Heating means 14, 15 Temperature measuring device 16 Humidity measuring devices 17, 27, 37 , 47, 57 Control means 21 Gas concentration measuring device 31 Bypass line 32 G / G heat exchanger 41 Heat pump 41A Heat pump body 41B, 51B Heating part 41C Cooling part 52 Heat exchanger

Claims (12)

  In the container into which the lignite to be dried is charged, air is supplied while stirring the lignite and the lignite is naturally heated, and the natural heat is generated until the humidity of the exhaust gas discharged from the container reaches a predetermined value. A method for drying lignite, wherein the lignite is dried by the accompanying heat.   While supplying the air while stirring the lignite in the container charged with the lignite to be dried, the lignite is naturally heated, and the temperature of the exhaust gas discharged from the container accompanying the spontaneous heat is measured, The exhaust gas has a predetermined temperature based on a drying characteristic representing a relationship between the temperature of the exhaust gas and the degree of drying of the lignite using at least one of the stirring speed, the air supply amount, or the temperature of the supply air as a parameter. The lignite is dried by raising the temperature until the lignite is dried.   While supplying the air while stirring the lignite in the container charged with the lignite to be dried, the lignite is naturally heated, and the specific gas in the exhaust gas discharged from the container accompanying the spontaneous heat Based on the drying characteristics representing the relationship between the concentration of the specific gas and the degree of drying of the lignite using at least one of the stirring speed, the air supply amount or the temperature of the supply air as a parameter A method for drying lignite, wherein the lignite is dried by raising the temperature until a specific gas has a predetermined concentration. In the drying method of the brown coal as described in any one of Claims 1-3,
A method for drying lignite, wherein the lignite is discharged from the container when the predetermined humidity, temperature, or concentration is reached, and new lignite is supplied. A container into which brown coal to be dried is charged;
Stirring means for stirring the lignite charged in the container;
Air supply means for supplying air into the container;
Humidity measuring means for measuring the humidity of the exhaust gas discharged from the container;
Control means for controlling at least one of the stirring speed, the air supply amount and the temperature of the supply air via the stirring means or the air supply system until the humidity measured by the humidity measuring means reaches a predetermined value; A lignite drying system characterized by comprising: A container into which brown coal to be dried is charged;
Stirring means for stirring the lignite charged in the container;
Air supply means for supplying air into the container;
Temperature measuring means for measuring the temperature of the exhaust gas discharged from the container;
The temperature of the exhaust gas is predetermined based on a drying characteristic representing a relationship between the temperature of the exhaust gas and the degree of drying of the lignite using at least one of the stirring speed, the air supply amount, or the temperature of the supply air as a parameter. And a control means for controlling at least one of the stirring speed, the air supply amount and the air temperature through the stirring means or the air supply system until reaching a value. . A container into which brown coal to be dried is charged;
Stirring means for stirring the lignite charged in the container;
Air supply means for supplying air into the container;
Concentration measuring means for measuring the concentration of a specific gas in the exhaust gas discharged from the container;
The concentration of the specific gas based on the drying characteristics representing the relationship between the concentration of the specific gas and the degree of drying of the lignite using at least one of the stirring speed, the air supply amount or the temperature of the supply air as a parameter Control means for controlling at least one of the stirring speed, the air supply amount, and the temperature of the air through the stirring means or the air supply system until the gas reaches a predetermined value. Drying system. In the drying system of the lignite according to any one of claims 5 to 7,
A drying system for lignite, comprising heating means for heating the lignite in the container. In the drying system of lignite according to claim 8,
The heating unit is formed by a heating unit of a heat pump, and the cooling unit of the heat pump is disposed in an air supply system between the air supply unit and the container to cool and dehumidify the air supplied to the container. A lignite drying system, characterized in that it is configured to do so. In the drying system of lignite according to claim 9,
The lignite drying system, wherein the heating unit is also disposed in the air supply system between the cooling unit and the container. In the drying system of the lignite according to any one of claims 5 to 10,
Brown coal characterized in that a heat exchanger for exchanging heat between the exhaust gas discharged from the container and the air supplied into the container through the air supply system is disposed in the air supply system. Drying system. In the drying system of the lignite according to any one of claims 5 to 11,
The lignite drying system further comprising nitrogen supply means for supplying nitrogen into the container.

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