JP2011214808A - Drying device, drying facility and drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drying device, a drying facility and a drying method capable of efficiently reusing gas discharged from inside of a drying container.SOLUTION: In the drying device 102 enabling drying while rotating on its axis, the drying container 120 having brown coal 101 supplied to inside, the drying container 120 includes: a steam inflow flow passage Renabling inflow of steam from outside of the drying container 120 to inside; a steam outflow flow passage Renabling outflow of steam from inside of the drying container 120 to outside. Generated steam 104 generated by drying the brown coal 101 can be discharged to outside of the drying container 120 via the steam outflow flow passage Rtogether with the steam made to flow in from the steam inflow flow passage R.

Description

  The present invention relates to a drying apparatus, a drying facility, and a drying method for drying an object to be dried such as lignite.

  Conventionally, as such a drying apparatus, a rotary dryer with a steam pipe provided with a rotating cylinder rotatable in the circumferential direction and a plurality of heating pipes arranged along an inner peripheral surface of the rotating cylinder is known. (For example, refer to Patent Document 1). This rotary dryer with a steam pipe is a so-called steam tube dryer, and the heating pipe uses steam as a heat medium. Therefore, the rotary dryer with a steam pipe heats the heating pipe while rotating the rotary cylinder, so that the wet coal supplied into the rotary cylinder is dried while being stirred.

Japanese Patent Laid-Open No. 5-117661

  By the way, when the wet coal is dried by the rotary dryer equipped with the steam pipe, steam generated when the wet coal is dried stays in the rotary cylinder. At this time, in order to discharge the steam staying inside the rotating cylinder, the vapor is discharged together with the non-condensable gas by supplying a non-condensable gas which is not likely to condense into the rotating cylinder. That is, by using the non-condensable gas to discharge the generated steam, the steam partial pressure of the atmosphere in the rotating cylinder is lowered, thereby promoting the drying of coal. Examples of the non-condensable gas include nitrogen, argon, and exhaust gas.

  However, when non-condensable gas is supplied into the rotating cylinder, the gas discharged from the rotating cylinder is a mixture of non-condensable gas and steam. At this time, since the non-condensable gas is difficult to condense even at a low temperature, it is difficult to improve the heat recovery efficiency when the non-condensable gas is reused in a heat recovery device such as a steam turbine generator. Become. For this reason, in the conventional rotary dryer with a steam pipe, it is difficult to efficiently reuse the gas discharged from the rotary cylinder.

  Then, this invention makes it a subject to provide the drying apparatus, the drying equipment, and the drying method which can reuse efficiently the gas discharged | emitted from the inside of a drying container.

  The drying apparatus of the present invention is a drying apparatus capable of drying while rotating a drying container supplied with an object to be dried. The drying container includes a steam inflow channel through which steam can flow from the outside to the inside of the drying container. And a steam outlet channel through which steam can flow from the inside to the outside of the drying container, and the generated steam generated by drying the material to be dried together with the steam flowing in from the steam inlet channel. It is possible to discharge to the outside of the drying container through the flow path.

  According to this configuration, the generated steam generated by drying the object to be dried can be discharged to the outside of the drying container by the steam flowing in from the steam inflow channel. For this reason, the gas discharged | emitted from the inside of a drying container can be made into only a vapor | steam. At this time, since the steam condenses at a higher temperature than conventional non-condensable gas, when the steam discharged from the inside of the drying container is reused in a heat recovery device such as a steam turbine generator, Heat recovery efficiency can be improved compared to the above.

  In this case, the apparatus further includes superheated steam supply means connected to the steam inflow channel and capable of supplying superheated steam as steam, and the superheated steam supply means supplies the superheated steam to the inside of the drying container to generate in the drying container. It is preferable that the steam is discharged together with the superheated steam to the outside of the drying container through the steam outlet channel.

  According to this configuration, the use of superheated steam as the steam can reduce the occurrence of condensation due to the steam. For this reason, corrosion due to the occurrence of condensation can be suppressed.

  In this case, at least a part of the steam including the generated steam discharged through the steam outflow channel is made to flow into the steam inflow channel, and the circulation channel and the drying container are interposed in the circulation channel. A circulation means for circulating the steam between the steam and the steam, and the circulation means, together with the steam flowing in from the circulation flow path through the steam inflow path, the steam generated in the drying container through the steam outflow path. It is preferable that it can be discharged to the outside of the drying container.

  According to this configuration, the generated steam generated by drying the object to be dried can be discharged to the outside of the drying container by the steam flowing in from the circulation channel through the steam inflow channel. For this reason, the gas discharged | emitted from the inside of a drying container can be made into only a vapor | steam. At this time, since the steam condenses at a higher temperature than the conventional non-condensable gas, when the steam discharged from the inside of the drying container is reused in a heat recovery device such as a gas turbine generator, Heat recovery efficiency can be improved compared to the above.

  In this case, it is detected by an air pressure detecting means capable of detecting the air pressure inside the drying container, a flow rate adjusting means interposed in the circulation channel and capable of adjusting a flow rate of the steam flowing into the drying container, and an air pressure detecting means. It is preferable to further include a flow rate control unit capable of controlling the flow rate adjustment unit based on the detected atmospheric pressure.

  According to this configuration, by controlling the flow rate adjusting means by the flow rate control means based on the detection result of the atmospheric pressure detection means, the atmospheric pressure inside the drying container can be adjusted to be able to dry the object to be dried satisfactorily. Can be controlled.

  The drying facility of the present invention is connected to the above-described drying device capable of drying the material to be dried, and the steam outflow passage of the drying device, and generates steam generated when the material to be dried is dried. Generated steam line discharged outside, dust collector installed in the generated steam line to remove dust in the generated steam, and installed downstream of the dust collector in the generated steam line to reduce the heat of the generated steam The heat recovery system to collect | recover and the cooler which cools the to-be-dried material dried with the drying apparatus are characterized by the above-mentioned.

  According to this configuration, since the gas discharged from the drying device can be only steam, the heat recovery efficiency in the heat recovery system can be improved.

  The drying method of the present invention is generated by drying the material to be dried by flowing steam into the inside of the drying container in the drying method of rotating while drying the drying container supplied with the material to be dried. The generated steam is discharged together with the introduced steam to the outside of the drying container.

  According to this configuration, the generated steam generated by drying the object to be dried can be discharged to the outside of the drying container by the steam flowing into the drying container. For this reason, the gas discharged | emitted from the inside of a drying container can be made into only a vapor | steam.

  According to the drying apparatus, the drying facility, and the drying method of the present invention, the gas discharged from the drying container can be only steam. For this reason, when the gas discharged from the drying container is reused by the heat recovery device, the steam condenses at a higher temperature than the conventional non-condensable gas. Can be made.

FIG. 1 is a schematic diagram illustrating an example of a drying facility to which the drying apparatus according to the first embodiment is applied. FIG. 2 is a schematic diagram illustrating an example of a combined coal gasification combined power generation system to which the drying facility illustrated in FIG. 1 is applied. FIG. 3 is a schematic diagram illustrating an example of a drying facility to which the drying apparatus according to the second embodiment is applied.

  Hereinafter, a drying apparatus, a drying facility, and a drying method according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following examples. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an example of a drying facility to which the drying apparatus according to the first embodiment is applied.

As shown in FIG. 1, the drying facility 100 generates a supply hopper 118 that supplies lignite with a high water content as a material to be dried, a drying device 102 that dries the lignite 101, and generation that occurs when the lignite 101 is dried. In the generated steam line L ₁ that discharges the steam 104 to the outside of the drying device 102, a dust collector 105 that is interposed in the generated steam line L ₁ and removes dust in the generated steam 104, and the generated steam line L ₁ A heat recovery system 106 that is disposed downstream of the dust collector 105 and recovers the heat of the generated steam 104, and a cooler 110 that cools the dried lignite 108 extracted from the drying device 102 to produce product coal 109. Are provided.

In the drying facility 100, the lignite 101 is fed into the drying device 102 by the supply hopper 118 through the supply line L ₀ .

The drying device 102 is a so-called steam tube dryer, and includes a drying container 120 into which the lignite 101 is charged and a heat transfer member 103 that heats the lignite 101 provided inside the drying container 120. The drying container 120 is formed in a cylindrical shape, and a drying chamber 126 is formed therein. The drying container 120 can be rotated in the circumferential direction about the axis I by a driving device (not shown). The drying container 120 is provided with a steam inflow channel R ₁ for supplying the superheated steam A from the outside to the inside. The superheated steam supply capable of supplying the superheated steam A is provided in the steam inflow channel R _1. A device (superheated steam supply means) 128 is connected. Furthermore, the drying vessel 120, the steam outlet channel R ₂ for discharging the steam from the inside to the outside is provided, this steam outlet channel R _2, generating steam line L ₁ is connected .

Therefore, the drying chamber 126 is supplied with the superheated steam A passes through the vapor inlet passage R _1, supplied superheated steam A is discharged to the outside of the drying chamber 126 by generating steam line L _1. In this case, steam generated 104 lignite 101 is generated when the drying, with superheated steam A, is discharged to the outside of the drying chamber 126 by generating steam line L _1.

The heat transfer member 103 removes moisture in the lignite 101 put into the drying chamber 126, and has a plurality of heating tubes 130 through which superheated steam (for example, 150 ° C. steam) A can circulate. The plurality of heating tubes 130 are arranged on the concentric circles at equal intervals along the inner peripheral surface of the drying container 120 formed in a cylindrical shape. In each heating tube 130, an inflow side end portion into which the superheated steam A flows and an outflow side end portion through which the superheated steam A flows out are arranged on one side in the axial direction of the drying container 120. For this reason, on one side (the left side in the drawing) of the drying container 120 in the axial direction, a steam supply flow path R ₃ for allowing the superheated steam A to flow into the inflow side ends of the plurality of heating tubes 130, and a plurality of heating tubes A steam discharge flow path R ₄ for allowing the superheated steam A to flow out from the outflow side end of 130 is provided. From the above, the superheated steam A flowing through the steam supply passage R _3, in order to branch to the inlet side end portion of the plurality of heat pipes 130, at a predetermined branching point P1, the inlet side end portions of a plurality of heating tubes 130 Are joined together. Similarly, the superheated steam A flowing through the plurality of heat pipes 130, in order to join the vapor discharge passage R _4, at a predetermined joining point P2, and is combined with the outflow-side ends of a plurality of heating tubes 130 . In Example 1, the inflow side end and the outflow side end of each heating tube 130 are arranged on one side in the axial direction of the drying container 120. However, the present invention is not limited to this, and the inflow side end of each heating tube 130 is arranged. May be arranged on one side of the drying container 120 in the axial direction, and the outflow side end of each heating tube 130 may be arranged on the other side of the drying container 120 in the axial direction.

Therefore, when 150 ° C. superheated steam A is supplied to each heating pipe 130 of the heat transfer member 103 through the steam supply flow path R ₃ , each heating pipe 130 uses the latent heat of the high-temperature superheated steam A. The lignite 101 is dried. Thereafter, the superheated steam A which is utilized for drying, as condensed water B of example 0.99 ° C., is discharged to the outside of the drying device 102 through a steam discharge flow path R _4.

  That is, since the superheated steam A condenses into liquid (moisture) on the inner surface of each heating tube 130, the latent heat of condensation radiated at this time is effectively used for heating the lignite 101 for drying. Any heating medium other than the high-temperature superheated steam A may be used as long as it is accompanied by a phase change. Examples thereof include Freon, pentane, and ammonia. In addition to using a heat medium as the heat transfer member 103, an electric heater may be installed.

Subsequently, a drying method using the drying apparatus 102 will be described. While rotating the drying container 120, the lignite 101 is put into the drying chamber 126 of the drying container 120 by the supply hopper 118. Then, the lignite 101 put into the drying chamber 126 is dried by being heated by the plurality of heating tubes 130 of the heat transfer member 103. The steam generated 104 generated by drying the lignite 101 by the heat transfer member 103, by supplying the superheated steam A from the steam inflow passage R _1, outside the drying chamber 126 from the steam outlet channel R _2, That is, it is discharged outside the drying apparatus 102.

Here, since the generated steam 104 discharged to the outside of the drying apparatus 102 includes a material obtained by drying and pulverizing the lignite 101, the collected steam 104 is collected by a dust collector 105 such as a cyclone or an electric dust collector to be solid. Separate as component 115. The solid component 115, through the separating line L _3, are mixed and joins the dry brown coal 108 withdrawn from the drying apparatus 102, which was cooled by the cooler 110, through the product line L _4, the product It is discharged as charcoal 109. This product charcoal 109 is used as a raw material for boilers, gasifiers, and the like.

  On the other hand, since the generated steam 104 after being collected by the dust collector 105 is, for example, steam at 105 to 110 ° C., it is recovered by the heat recovery system 106, processed by the water treatment unit 112, and drained 113. As shown in FIG. The generated steam 104 after being collected by the dust collector 105 is applied to, for example, a heat exchanger, a steam turbine generator, etc., and the heat is effectively used.

  In addition, although the brown coal 101 was illustrated as to-be-dried material, as long as it has a high water content, it is good also considering to-be-dried materials, such as low grade coal containing subbituminous coal, sludge, etc., and sludge.

  Next, an example applied to a coal gasification combined power generation (IGCC) system using the product charcoal 109 dried by the drying equipment 100 to which the drying apparatus 102 according to the first embodiment is applied will be described. FIG. 2 is a schematic diagram illustrating an example of a combined coal gasification combined power generation system to which the drying facility illustrated in FIG. 1 is applied.

  As shown in FIG. 2, the combined coal gasification combined power generation system 200 treats pulverized coal 201 a obtained by pulverizing the product charcoal 109 with a mill 210 after drying the brown coal 101 as the fuel with the drying equipment 100 to obtain the product charcoal 109. Then, a coal gasification furnace 203 that converts the gasification gas 202 into a gas, a gas turbine (GT) 204 that is operated using the gasification gas 202 as fuel, and exhaust heat recovery that introduces the turbine exhaust gas 205 from the gas turbine 204. A steam turbine (ST) 208 operated by steam 207 generated by a boiler (Heat Recovery Steam Generator: HRSG) 206, a gas turbine 204 and / or a generator (G) 209 connected to the steam turbine 208, Is provided.

The coal gasification combined power generation system 200 gasifies pulverized coal 201a pulverized by a mill 210 in a coal gasification furnace 203 to obtain a gasified gas 202 which is a generated gas. The gasified gas 202 is dust-removed and gas-purified by a cyclone 211 and a gas purifier 212, and then supplied to a combustor 213 of a gas turbine 204, which is a power generation means. Is generated. The gas turbine 204 is driven by the combustion gas 214. The gas turbine 204 is connected to a generator 209, and the generator 209 generates electric power when the gas turbine 204 is driven. Since the turbine exhaust gas 205 after driving the gas turbine 204 still has a temperature of about 500 to 600 ° C., it is sent to an exhaust heat recovery boiler (HRSG) 206, where thermal energy is recovered. In the exhaust heat recovery boiler (HRSG) 206, steam 207 is generated by the thermal energy of the turbine exhaust gas 205, and the steam turbine 208 is driven by the steam 207. The exhaust gas 215 from which heat energy has been recovered by the exhaust heat recovery boiler (HRSG) 206 is released into the atmosphere via the chimney 217 after the NOx and SOx components in the exhaust gas 215 are removed by the gas purification device 216. . In the figure, reference numeral 218 denotes a condenser, 219 denotes air, 220 denotes a compressor, and 221 denotes an air separation device (ASU) that separates air into nitrogen (N ₂ ) and oxygen (O ₂ ). .

  According to the combined coal gasification combined power generation system 200, even when the lignite 101 having high moisture is used for gasification, since the lignite 101 is dried by the efficient drying device 102, the gasification efficiency is improved. It is possible to generate power stably over a long period of time.

  In addition, as a power generation system using the product charcoal 109 dried with the drying equipment 100 which concerns on a present Example, it is not restricted to the coal gasification combined cycle power generation system 200 mentioned above. For example, although not shown in the figure, power generation by a lignite coal boiler that supplies product charcoal 109 dried by the drying facility 100 to a boiler furnace, drives a steam turbine with steam generated in the boiler furnace, and obtains output by a generator. It may be a system.

According to the above configuration, by using the drying apparatus 102 of Example 1, the steam generated 104 generated by drying the lignite 101, the superheated steam A supplied from the steam inflow passage R _1, drying chamber 126 can be discharged to the outside. Thereby, since only the steam is discharged from the drying chamber 126, a decrease in heat recovery efficiency in the heat recovery system 106 can be suppressed.

  Next, the drying apparatus 250 of Example 2 is demonstrated with reference to drawings. FIG. 3 is a schematic diagram illustrating an example of a drying facility to which the drying apparatus according to the second embodiment is applied. Only different parts will be described in order to avoid duplicate descriptions. The drying apparatus 102 according to the first embodiment discharges the generated steam 104 generated from the lignite 101 to the outside of the drying chamber 126 by supplying the superheated steam A to the drying chamber 126. On the other hand, the drying apparatus 250 according to the second embodiment discharges the generated steam 104 generated from the brown coal 101 to the outside of the drying chamber 126 by operating a circulation fan (circulation means) 255. Hereinafter, the drying apparatus 250 of Example 2 will be described in detail.

In addition to the configuration of the drying device 102 of the first embodiment, the drying device 250 of the second embodiment includes a circulation line L ₂ connected from the steam outlet channel R ₂ to the steam inlet channel R ₁ , and an intervening circuit in the circulation line L ₂ . a circulation fan 255 which is, circulation line L ₂ to the interposed a flow regulating valve (flow rate adjusting means) 256, a drying chamber capable of detecting pressure sensor pressure 126 (pressure detecting means) 257, flow control valve And a flow rate control device (flow rate control means) 258 capable of controlling 256.

  The circulation fan 255 blows the generated steam 104 generated in the drying chamber 126 toward the dust collector 105. That is, by operating the circulation fan 255, the intake side of the circulation fan 255 sucks the atmosphere in the drying chamber 126. Thereby, the circulation fan 255 can discharge the generated steam 104 generated in the drying chamber 126 to the outside of the drying chamber 126.

The circulation line L < _b > ₂ is a line for supplying the generated steam 104 discharged from the drying chamber 126 into the drying chamber 126 again through the dust collector 105. In other words, the circulation line L ₂ is partially overlaps with a part of the generated steam line L _1. A part of the generated steam 104 after being collected by the dust collector 105 is sent to the drying chamber 126 through the circulation line L ₂ , and the generated steam 104 generated in the drying chamber 126 is discharged. Used. The circulation line L ₂ is provided with a butterfly flow rate adjustment valve 256, and the flow rate of the generated steam 104 flowing into the drying chamber 126 is adjusted by adjusting the opening degree of the flow rate adjustment valve 256. It is adjustable.

  The flow rate control device 258 adjusts the flow rate adjustment valve 256 based on the detection result of the atmospheric pressure sensor 257. More specifically, the flow control device 258 determines whether or not the detected atmospheric pressure input from the atmospheric pressure sensor 257 is a preset atmospheric pressure, that is, an atmospheric pressure at which the lignite 101 is suitably dried. As a result of the determination, when the detected atmospheric pressure is equal to or higher than the set atmospheric pressure, the flow control device 258 controls the flow rate adjustment valve 256 to the valve closing side, while when the detected atmospheric pressure is less than the set atmospheric pressure, The flow rate adjustment valve 256 is controlled to the valve opening side.

Next, a drying method using the drying device 250 will be described. While rotating the drying container 120, the lignite 101 is put into the drying chamber 126 of the drying container 120 by the supply hopper 118. Then, the lignite 101 put into the drying chamber 126 is dried by being heated by the plurality of heating tubes 130 of the heat transfer member 103. Then, the generated steam 104 generated by drying the lignite 101 is discharged from the drying chamber 126 via the steam outflow passage R ₂ by the operation of the circulation fan 255, and the generated steam line L ₁ (circulation line L _2). Part of). Generating steam 104 which has passed through the dust collector 105 is partially introduced into the circulation line L _2. In this case, flow control valve 256 interposed in the circulation line L ₂ is, by the flow control device 258, the opening, air pressure in the drying chamber 126 is adjusted so that the set pressure, the circulation line L ₂ The introduced generated steam 104 passes through the flow rate adjustment valve 256 so that the flow rate of the generated steam 104 is adjusted and supplied to the drying chamber 126.

According to the above configuration, by using the drying apparatus 250 of Example 2, the steam generated 104 generated by drying the lignite 101, by generating steam 104 supplied from the circulation line L _2, the drying chamber 126 It can be discharged to the outside. Thereby, since only the steam is discharged from the drying chamber 126, a decrease in heat recovery efficiency in the heat recovery system 106 can be suppressed.

  Further, the drying device 250 controls the flow rate adjustment valve 256 by the flow rate control device 258 based on the detected atmospheric pressure detected by the atmospheric pressure sensor 257, thereby favorably drying the brown coal 101 with the atmospheric pressure inside the drying container 120. It is possible to control the atmospheric pressure.

In Example 2, it is provided with the circulation fan 255 to generate steam line _{L 1} between the drying vessel 120 and dust collector 105, instead of this, the circulation fan 255 and the flow control valve 256 the drying vessel 120 it may be provided on the circulation line L ₂ between. According to this configuration, the circulation fan 255 can blow the generated steam 104 introduced into the circulation line L ₂ toward the drying container 120. That is, by operating the circulation fan 255, the exhaust side of the circulation fan 255 supplies the generated steam 104 into the drying chamber 126. Thereby, the circulation fan 255 can discharge the generated steam 104 generated in the drying chamber 126 to the outside of the drying chamber 126.

Further, in addition to the configuration of the drying apparatus 250 of Example 2, may be interposed superheater superheater and heater into the circulation line L _2. According to this configuration, since the generated steam 104 can be superheated steam, the occurrence of condensation due to the steam can be reduced, and corrosion due to the occurrence of condensation can be suppressed.

  As described above, the drying apparatus according to the present invention is useful in a steam tube dryer, and is particularly suitable when lignite is used as an object to be dried.

DESCRIPTION OF SYMBOLS 100 Drying equipment 101 Brown coal 102 Drying device 103 Heat transfer member 104 Generated steam 105 Dust collector 106 Heat recovery system 108 Dry lignite 109 Product coal 110 Cooler 120 Drying vessel 126 Drying chamber 128 Superheated steam supply device 200 Coal gasification combined power generation system 250 Drying device (Example 2)
255 Circulating fan 256 Flow rate adjusting valve 257 Pressure sensor 258 Flow rate control device A Superheated steam B Condensed water L ₁ Generation steam line L ₂ Circulation line (Example 2)
L ₃ separation line L ₄ product line R ₁ steam inflow path R ₂ steam outflow path R ₃ steam supply path R ₄ steam discharge path

Claims (6)

In a drying device capable of drying while rotating the drying container supplied with the material to be dried,
The drying container is
A steam inflow passage through which steam can flow from the outside to the inside of the drying container;
A steam outflow passage through which steam can flow out from the inside of the drying container, and
Generated steam generated by drying the material to be dried can be discharged to the outside of the drying container through the steam outflow passage together with the steam flowing in from the steam inflow passage. And drying equipment. The apparatus further comprises superheated steam supply means connected to the steam inflow channel and capable of supplying superheated steam as steam,
The superheated steam supply means supplies the superheated steam to the inside of the drying container, and the generated steam in the drying container, together with the superheated steam, to the outside of the drying container through the steam outlet channel. The drying apparatus according to claim 1, wherein the drying apparatus is discharged. A circulation passage for causing at least a part of the steam including the generated steam discharged through the steam outflow passage to flow into the steam inflow passage;
A circulation means interposed in the circulation flow path for circulating steam between the circulation flow path and the drying container,
The circulation means is capable of discharging the generated steam in the drying container to the outside of the drying container through the steam outflow passage together with the steam flowing in from the circulation passage through the steam inflow passage. The drying apparatus according to claim 1, wherein Atmospheric pressure detection means capable of detecting the atmospheric pressure inside the drying container;
A flow rate adjusting means interposed in the circulation channel and capable of adjusting the flow rate of the steam flowing into the drying container;
The drying apparatus according to claim 3, further comprising a flow rate control unit capable of controlling the flow rate adjustment unit based on a detected atmospheric pressure detected by the atmospheric pressure detection unit. The drying apparatus according to any one of claims 1 to 4, capable of drying an object to be dried;
A generated steam line that is connected to the steam outflow passage of the drying apparatus and that generates generated steam when the material to be dried is dried, to the outside of the drying apparatus;
A dust collector that is interposed in the generated steam line and removes dust in the generated steam;
A heat recovery system that is interposed downstream of the dust collector in the generated steam line and recovers the heat of the generated steam;
And a cooler for cooling the material to be dried dried by the drying device. In the drying method of drying while rotating the drying container supplied with the material to be dried inside,
A drying method characterized by causing steam to flow into the drying container and discharging generated steam generated by drying the material to be dried to the outside of the drying container together with the steam that has flowed in. .

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