JP5473732B2 - Low grade coal drying system - Google Patents

Description

  The present invention relates to a low-grade coal drying system that uses, as a heat source, steam generated when low-grade coal is dried by a low-grade coal drying apparatus.

  For example, the Integrated Coal Gasification Combined Cycle (IGCC) system gasifies coal and combines it with combined cycle power generation consisting of a gas turbine and a steam turbine to achieve higher efficiency than conventional coal-fired power generation. This is a power generation system that aims to make it more environmentally friendly. This coal gasification combined power generation system has a great merit that it can use coal with abundant resources, and it is known that the merit will be further increased by expanding the types of applied coal.

  However, low-grade coal such as lignite and sub-bituminous coal has a large amount of moisture that is brought in, and there is a problem that power generation efficiency decreases due to this moisture. For this reason, it is necessary to dry the low-grade coal to remove moisture.

  Conventionally, for example, a low-grade coal drying system (a power generation method using low-grade coal as a fuel) described in Patent Document 1 shows a dehydration reforming process for removing moisture from low-grade coal. In this dehydration reforming process, the evaporated and separated water is in a vapor state, and the latent heat of evaporation generated by compressing this steam with a compressor is recovered and reused as a heat source required in the dehydration reforming process.

Japanese Patent No. 4153448

  However, the steam released from the low-grade coal contains fine particles contained in the low-grade coal. When this steam is introduced into a rotary machine such as a compressor, the fine particles cause wear of the blades of the rotary machine. There is a fear. For this reason, it is necessary to remove the fine particles by passing the steam before reaching the rotating machine through the dust collector. However, since the vapor condenses in the dust collector, the dust collector may be clogged by the condensed water. is there.

  In view of the above-mentioned problems, the present invention suppresses the wear of blades of a rotating machine when the steam generated when the low-grade coal is dried is introduced into the rotating machine, while suppressing the wear of the rotating machine blades. An object is to provide a low-grade coal drying system capable of preventing clogging.

  In order to achieve the above-mentioned object, the low-grade coal drying system of the present invention includes a low-grade coal drying device that indirectly dries low-grade coal with the latent heat of superheated steam, and generation generated from the low-grade coal by drying. A rotating machine into which steam is introduced; a dust collector that is provided during the introduction of the generated steam from the low-grade coal drying apparatus to the rotating machine; The low-grade coal is provided by indirect heat exchange with the condensed water in which the superheated steam obtained by drying the low-grade coal is provided while the generated steam is introduced from the grade-coal dryer to the dust collector. And a pre-dust collection heater that heats the generated steam before reaching the dust collection device from a drying device.

  According to this low-grade coal drying system, it is possible to suppress the situation where the blades of the rotating machine are worn by removing the fine particles contained in the generated steam by the dust collector. In addition, since the generated steam before reaching the dust collector is heated by the pre-dust collector heater, the generated steam is prevented from condensing in the dust collector. The clogging of the device can be prevented. In addition, the pre-dust collector heater indirectly heats the generated steam with the high-temperature condensed water condensed by the superheated steam that dries the low-grade coal, effectively using the heat used in the low-grade coal drying system. Can be used.

  In the low-grade coal drying system of the present invention, the pre-dust collection heater includes a casing through which the generated steam passes, a tubular heat transfer member provided in the casing and supplied with the condensed water, A water spray nozzle for spraying cleaning water to the outside of the heat transfer member in the casing is provided.

  According to this low-grade coal drying system, the heat transfer efficiency in the heat transfer member can be maintained by washing the fine particles adhering to the heat transfer member with the washing water sprayed from the water spray nozzle.

  Further, in the low-grade coal drying system of the present invention, the condensed water condensed with the superheated steam provided while the generated steam is introduced from the dust collector to the rotary machine and drying the low-grade coal; And a post-dust collection heater that heats the generated steam from the dust collector to the rotary machine by indirect heat exchange.

  According to this low-grade coal drying system, the generated steam from the dust collector to the rotating machine is heated by the post-dust collection heater, thereby preventing condensation of the generated steam and improving the thermal efficiency used in the rotating machine. be able to. In addition, since the post-dust collection heater indirectly heats the generated steam with high-temperature condensed water condensed with superheated steam that dries low-grade coal, it effectively uses the heat used in this low-grade coal drying system. Can be used.

  In the low-grade coal drying system of the present invention, the rotating machine is a compressor that compresses the generated steam generated from the low-grade coal by drying into high-temperature and high-pressure superheated steam.

  According to this low-grade coal drying system, the steam generated when the low-grade coal is dried can be effectively used as a heat source for introducing and compressing the generated steam into the compressor to dry the low-grade coal. In addition, the generated steam is heated by the pre-dust collection heater (and the post-dust collection heater), thereby preventing the generated steam from condensing and improving the compression efficiency in the compressor.

  In the low-grade coal drying system of the present invention, the rotating machine is a steam turbine that is operated using the generated steam generated from the low-grade coal by drying.

  According to this low-grade coal drying system, the steam turbine is operated by the steam generated when the low-grade coal is dried, so the steam generated by drying the low-grade coal is effectively used for steam turbine operation. can do. In addition, the generated steam is heated by the pre-dust collection heater (and the post-dust collection heater), thereby preventing the generated steam from condensing and improving the power generation efficiency in the steam turbine.

  According to the present invention, when steam generated when low-grade coal is dried is introduced into a rotating machine, wear of the blade of the rotating machine is suppressed by the dust collecting apparatus, and clogging of the dust collecting apparatus is prevented. can do.

FIG. 1 is a schematic diagram illustrating an example of a low-grade coal drying system. FIG. 2 is a schematic diagram showing an example of a combined coal gasification combined power generation system to which the low-grade coal drying system shown in FIG. 1 is applied. FIG. 3 is a schematic diagram of the low-grade coal drying system according to Embodiment 1 of the present invention. FIG. 4 is a schematic diagram of another example of the low-grade coal drying system according to Embodiment 1 of the present invention. FIG. 5 is a schematic diagram of a low-grade coal drying system according to Embodiment 2 of the present invention. FIG. 6 is a schematic diagram of another example of the low-grade coal drying system according to Embodiment 2 of the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. 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.

  The present embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an example of a low-grade coal drying system.

As shown in FIG. 1, a low-grade coal drying system 100 includes a low-grade coal drying device 102 that dries a low-grade coal 101 such as lignite having a high water content, and a low-grade coal drying device 102 that is tubular. A heat transfer member 103 that supplies superheated steam (for example, 150 ° C. steam) A inside to remove moisture in the low-grade coal 101, and generation that occurs when the low-grade coal 101 is dried by the heat transfer member 103 A generated steam line L ₁ that discharges the steam 104 to the outside of the low-grade coal 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 dust collection tap a portion of the steam generated 104 dust is removed from the apparatus 105, the branch line L ₂ to be supplied to the low-grade coal drying device 102 as a fluidizing steam 107, withdrawn from the low-grade coal drying device 102 The dried coal 108 is cooled is intended and a cooler 110 to a product coal 109.

  In the low-grade coal drying system 100, the low-grade coal 101 is introduced into the low-grade coal drying apparatus 102 by a supply means (not shown) and is fluidized by the fluidized steam 107 separately introduced into the low-grade coal drying apparatus 102. A fluidized bed 111 is formed. The heat transfer member 103 described above is disposed in the fluidized bed 111. The superheated steam A at 150 ° C. is supplied into the heat transfer member 103, and the low-grade coal 101 is dried indirectly using the latent heat of the high-temperature superheated steam A. The superheated steam A used for drying is discharged to the outside of the low-grade coal drying apparatus 102 as, for example, 150 ° C. condensed water B.

  That is, on the inner surface of the heat transfer member 103 that is a heating means, the superheated steam A condenses into a liquid (moisture), so that the condensed latent heat radiated at this time is effectively used for heating the low-grade coal 101 for drying. ing. 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.

The generated steam 104 generated when the low-grade coal 101 is dried by the heat transfer member 103 is generated from the free board portion F formed in the upper space of the fluidized bed 111 in the low-grade coal drying apparatus 102. ₁ is discharged to the outside of the low-grade coal drying apparatus 102. Since the generated steam 104 includes a powder obtained by drying and pulverizing the low-grade coal 101, the generated steam 104 is collected by a dust collector 105 such as a cyclone or an electric dust collector and separated as a solid component 115. This solid component 115 is mixed with the dry coal 108 extracted from the low-grade coal drying apparatus 102 and cooled by the cooler 110 to obtain the product coal 109. This product charcoal 109 is used as a raw material for boilers, gasifiers, and the like.

On the other hand, the generated steam 104 after being collected by the dust collector 105 is discharged to the outside of the low-grade coal drying system 100 as steam at 105 to 110 ° C., for example. Part of the steam generated 104 after being dust collecting by a dust collector 105, is sent to the low-grade coal drying device 102 by the circulation fan 114 interposed in the branch line L _2, low-grade coal 101 Is used as fluidized steam 107 for fluidizing the fluidized bed 111. In addition, as a fluidizing medium for fluidizing the fluidized bed 111, a part of the generated steam 104 is reused, but is not limited to this, for example, nitrogen, carbon dioxide, or a low oxygen concentration containing these gases. Air may be used.

  In addition, although the low grade coal 101 was illustrated as a to-be-dried material dried with the low-grade coal drying apparatus 102 mentioned above, as long as a moisture content is high, to-be-dried materials other than the low grade coal 101 may be made into drying object.

  An example applied to a coal gasification combined power generation (IGCC) system using the product coal 109 dried by the above-described low-grade coal drying apparatus 102 will be described. FIG. 2 is a schematic diagram showing an example of a combined coal gasification combined power generation system to which the low-grade coal drying system shown in FIG. 1 is applied.

  As shown in FIG. 2, the coal gasification combined power generation system 200 treats pulverized coal 201 a obtained by pulverizing coal (product charcoal 109 dried by the low-grade coal drying system 100) into a gasification gas 202. A coal gasification furnace 203 for conversion, a gas turbine (GT) 204 operated using the gasification gas 202 as a fuel, and a heat recovery steam generator (heat recovery steam generator) for introducing turbine exhaust gas 205 from the gas turbine 204 The steam turbine (ST) 208 operated by the steam 207 generated by the HRSG) 206, and the generator (G) 209 connected to the gas turbine 204 and / or the steam turbine 208 are 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 subjected to dust removal and gas purification by a cyclone 211 and a gas purification device 212, and then supplied to a combustor 213 of a gas turbine 204, which is a power generation means, where it is burned to produce a high-temperature and high-pressure combustion gas 214. Generate. 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 this coal gasification combined cycle power generation system 200, even when gasifying using low-grade coal 101 having high moisture, the low-grade coal 101 is dried by the efficient low-grade coal drying device 102. Gasification efficiency is improved and power generation can be performed stably over a long period of time.

Moreover, in the coal gasification combined cycle power generation system 200, the efficiency of the coal-fired power plant, which has been about 40% in the past, can be improved to about 46% by combining the gas turbine and the steam turbine. By improving the plant efficiency, CO ₂ emissions can be reduced by about 13% compared to conventional coal fired boilers.

  Note that the power generation system using the product coal 109 dried by the low-grade coal drying system 100 according to the present embodiment is not limited to the coal gasification combined power generation system 200 described above. For example, although not clearly shown in the figure, the charcoal 109 dried by the low-grade coal drying system 100 is supplied to a boiler furnace, the steam turbine is driven by steam generated in the boiler furnace, and the output is generated by a generator. A power generation system using a boiler may be used.

[Embodiment 1]
FIG. 3 is a schematic diagram of a low-grade coal drying system according to the present embodiment. As shown in FIG. 3, the low-grade coal drying system 100 of the present embodiment boosts the generated steam 104 at about 105 to 110 ° C. after being collected by the dust collector 105, thereby increasing the temperature and pressure. Steam (for example, 150 ° C. steam) A is used, and this superheated steam A is supplied to the heat transfer member 103 of the low-grade coal drying apparatus 102 and used to dry the low-grade coal 101.

Specifically, the generated steam 104 of about 105 to 110 ° C. generated by drying the low-grade coal 101 is discharged to the outside of the low-grade coal drying apparatus 102 through the generated steam line L ₁ and generated by the dust collector 105. Fine particles contained in the vapor 104 are collected. The generated steam 104 that has passed through the dust collector 105 is supplied to a compressor 120 serving as a rotating machine, and becomes superheated steam A that is boosted to, for example, 150 ° C. and supplied to the heat transfer member 103.

Moreover, low-grade coal drying system 100 of the present embodiment, the dust collecting pre-heater 121 to generate steam line L ₁ while generating steam 104 to the low-grade coal drying device 102 from the dust collector 105 is introduced provided It has been. In the pre-dust collection heater 121, a tubular heat transfer member 121b is provided in a casing 121a through which the generated steam 104 passes. Condensed water B (for example, 150 ° C. condensed water) obtained by condensing superheated steam A obtained by drying low-grade coal is supplied into the heat transfer member 121b. Thereby, the generated steam 104 is indirectly heated using the latent heat of the high-temperature condensed water B.

As described above, the low-grade coal drying system 100 according to the present embodiment is generated from the low-grade coal drying apparatus 102 that indirectly dries the low-grade coal 101 with the latent heat of the superheated steam A and the low-grade coal 101 by drying. Included in the generated steam 104 provided in the generated steam line L ₁ during the introduction of the generated steam 104 from the low-grade coal drying apparatus 102 to the compressor 120 as a rotating machine into which the generated steam 104 is introduced. Dust collector 105 that collects fine particles to be collected, and low-grade coal 101 provided in generated steam line L ₁ while steam 104 is introduced from low-grade coal dryer 102 to dust collector 105. A pre-dust collection heater 121 that heats the generated steam 104 from the low-grade coal drying apparatus 102 to the dust collection apparatus 105 by indirect heat exchange with the condensed water B condensed with the superheated steam A. Obtain.

  According to the low-grade coal drying system 100, it is possible to suppress the situation where the blades of the compressor 120 are worn by removing the fine particles contained in the generated steam 104 by the dust collector 105. Moreover, since the generated steam 104 before reaching the dust collector 105 is heated by the pre-dust collector heater 121 to prevent the generated steam 104 from condensing in the dust collector 105, the particulates in the dust collector 105 due to condensed water can be reduced. It is possible to prevent adhesion and prevent the dust collector 105 from being clogged. Moreover, since the pre-dust collection heater 121 indirectly heats the generated steam 104 with the high-temperature condensed water B condensed with the superheated steam A that dries the low-grade coal 101, the low-grade coal drying system 100. It is possible to effectively use the heat used in.

  Moreover, in the low-grade coal drying system 100 of this Embodiment, the pre-dust collection heater 121 is provided with the water spray nozzle 121c which sprays the washing water S on the exterior of the heat-transfer member 121b within the casing 121a.

  According to this low-grade coal drying system 100, it is possible to maintain the heat transfer efficiency in the heat transfer member 121b by cleaning the fine particles adhering to the heat transfer member 121b with the cleaning water S sprayed from the water spray nozzle 121c. Become.

FIG. 4 is a schematic diagram of another example of the low-grade coal drying system according to the present embodiment. As shown in FIG. 4, the low-grade coal drying system 100 is generated while the generated steam 104 is introduced from the dust collector 105 to the compressor 120 as a rotating machine in the low-grade coal drying system 100 shown in FIG. 3. dust collector after the heater 122 is further provided in the steam line L _1. In the post-dust collection heater 122, a tubular heat transfer member 122b is provided in a casing 122a through which the generated steam 104 passes. Condensed water B (for example, 150 ° C. condensed water) condensed with superheated steam A obtained by drying low-grade coal is supplied into the heat transfer member 122b. Thereby, the generated steam 104 is indirectly heated using the latent heat of the high-temperature condensed water B.

That is, in the low-grade coal drying system 100 of the present embodiment, low-grade coal 101 provided in the development steam line L ₁ while generating steam 104 to the compressor 120 as a rotating machine from the dust collector 105 is introduced And a post-dust collection heater 122 for heating the generated steam 104 before reaching the compressor 120 from the dust collector 105 by indirect heat exchange with the condensed water B condensed with the superheated steam A dried.

  According to this low-grade coal drying system 100, the generated steam 104 before reaching the compressor 120 from the dust collector 105 is heated by the post-dust collection heater 122, thereby preventing the generated steam 104 from condensing and the compressor 120. The compression efficiency can be improved. In addition, since the post-dust collection heater 122 indirectly heats the generated steam 104 with the high-temperature condensed water B condensed with the superheated steam A that dries the low-grade coal 101, the low-grade coal drying system 100. It is possible to effectively use the heat used in.

  As described above, in the low-grade coal drying system 100 of the present embodiment, as a rotary machine, the generated steam 104 generated from the low-grade coal 101 by drying is compressed into a high-temperature and high-pressure superheated steam A. 120 is applied.

  According to the low-grade coal drying system 100, the generated steam 104 generated when the low-grade coal 101 is dried is introduced into the compressor 120 and compressed to be effectively used as a heat source for drying the low-grade coal 101. Is possible. Moreover, by heating the generated steam 104 by the pre-dust collection heater 121 (and the post-dust collection heater 122), it is possible to prevent condensation of the generated steam 104 and improve the compression efficiency in the compressor 120.

[Embodiment 2]
FIG. 5 is a schematic diagram of a low-grade coal drying system according to the present embodiment. As shown in FIG. 5, the low-grade coal drying system 100 according to the present embodiment uses the above-described coal gasification combined power generation system to generate steam 104 at about 105 to 110 ° C. after being collected by the dust collector 105. In 200, the steam turbine (ST) 208 is supplied to a steam turbine (ST) 123 different from the steam turbine (ST) 208 and used effectively for power generation.

Specifically, the generated steam 104 of about 105 to 110 ° C. generated by drying the low-grade coal 101 is discharged to the outside of the low-grade coal drying apparatus 102 through the generated steam line L ₁ and generated by the dust collector 105. Fine particles contained in the vapor 104 are collected. The generated steam 104 that has passed through the dust collector 105 is supplied to a steam turbine 123 serving as a rotating machine.

Moreover, low-grade coal drying system 100 of the present embodiment, the dust collecting pre-heater 121 to generate steam line L ₁ while generating steam 104 to the low-grade coal drying device 102 from the dust collector 105 is introduced provided It has been. In the pre-dust collection heater 121, a tubular heat transfer member 121b is provided in a casing 121a through which the generated steam 104 passes. In the heat transfer member 121b, condensed water B (for example, 150 ° C. condensed) condensed with superheated steam A (for example, steam extracted from the steam turbine 208 of the coal gasification combined power generation system 200 described above) obtained by drying low-grade coal. Water). Thereby, the generated steam 104 is indirectly heated using the latent heat of the high-temperature condensed water B.

As described above, the low-grade coal drying system 100 according to the present embodiment is generated from the low-grade coal drying apparatus 102 that indirectly dries the low-grade coal 101 with the latent heat of the superheated steam A and the low-grade coal 101 by drying. A steam turbine 123 as a rotating machine into which the generated steam 104 is introduced, and included in the generated steam 104 provided in the generated steam line L ₁ while the generated steam 104 is introduced from the low-grade coal drying apparatus 102 to the steam turbine 123. Dust collector 105 that collects fine particles to be collected, and low-grade coal 101 provided in generated steam line L ₁ while steam 104 is introduced from low-grade coal dryer 102 to dust collector 105. Pre-dust collection heating that heats the generated steam 104 from the low-grade coal dryer 102 to the dust collector 105 by indirect heat exchange with the condensed water B condensed with the superheated steam A. And a 121.

  According to the low-grade coal drying system 100, it is possible to suppress the situation where the blades of the steam turbine 123 are worn by removing the fine particles contained in the generated steam 104 by the dust collector 105. Moreover, since the generated steam 104 before reaching the dust collector 105 is heated by the pre-dust collector heater 121 to prevent the generated steam 104 from condensing in the dust collector 105, the particulates in the dust collector 105 due to condensed water can be reduced. It is possible to prevent adhesion and prevent the dust collector 105 from being clogged. Moreover, since the pre-dust collection heater 121 indirectly heats the generated steam 104 with the high-temperature condensed water B condensed with the superheated steam A that dries the low-grade coal 101, the low-grade coal drying system 100. It is possible to effectively use the heat used in.

  Moreover, in the low-grade coal drying system 100 of this Embodiment, the pre-dust collection heater 121 is provided with the water spray nozzle 121c which sprays the washing water S on the exterior of the heat-transfer member 121b within the casing 121a.

  According to this low-grade coal drying system 100, it is possible to maintain the heat transfer efficiency in the heat transfer member 121b by cleaning the fine particles adhering to the heat transfer member 121b with the cleaning water S sprayed from the water spray nozzle 121c. Become.

FIG. 6 is a schematic diagram of another example of the low-grade coal drying system according to the present embodiment. As shown in FIG. 6, the low-grade coal drying system 100 is generated while the generated steam 104 is introduced from the dust collector 105 to the steam turbine 123 as a rotating machine in the low-grade coal drying system 100 shown in FIG. 5. dust collector after the heater 122 is further provided in the steam line L _1. In the post-dust collection heater 122, a tubular heat transfer member 122b is provided in a casing 122a through which the generated steam 104 passes. Condensed water B (for example, 150 ° C. condensed water) condensed with superheated steam A obtained by drying low-grade coal is supplied into the heat transfer member 122b. Thereby, the generated steam 104 is indirectly heated using the latent heat of the high-temperature condensed water B.

That is, in the low-grade coal drying system 100 of the present embodiment, low-grade coal 101 provided in the development steam line L ₁ while generating steam 104 to the steam turbine 123 as a rotating machine from the dust collector 105 is introduced And a post-dust collection heater 122 for heating the generated steam 104 before reaching the steam turbine 123 from the dust collector 105 by indirect heat exchange with the condensed water B condensed with the superheated steam A dried.

  According to the low-grade coal drying system 100, the generated steam 104 before reaching the steam turbine 123 from the dust collector 105 is heated by the post-dust collection heater 122, thereby preventing the generated steam 104 from condensing and the steam turbine 123. It is possible to improve the power generation efficiency at the plant. In addition, since the post-dust collection heater 122 indirectly heats the generated steam 104 with the high-temperature condensed water B condensed with the superheated steam A that dries the low-grade coal 101, the low-grade coal drying system 100. It is possible to effectively use the heat used in.

  As described above, in the low-grade coal drying system 100 of the present embodiment, the steam turbine 123 that is operated using the generated steam 104 generated from the low-grade coal 101 by drying is applied as the rotating machine. .

  According to the low-grade coal drying system 100, the steam turbine 123 is operated by the generated steam 104 generated when the low-grade coal 101 is dried. It can be effectively used for the operation of the turbine 123. In addition, the generated steam 104 is heated by the pre-dust collection heater 121 (and the post-dust collection heater 122), thereby preventing the generated steam 104 from condensing and improving the power generation efficiency in the steam turbine 123.

  In the low-grade coal drying system 100 according to Embodiment 1 and Embodiment 2 described above, the low-grade coal drying device 102 has been described as a tubular heat transfer member 103, but superheated steam A is supplied to the inside. For example, a plate shape may be used.

  Further, in the low-grade coal drying system 100 according to the first and second embodiments described above, the low-grade coal drying apparatus 102 includes the low-grade coal 101 in which the fluidized steam 107 is introduced into the low-grade coal drying apparatus 102. Although the so-called fluidized bed drying apparatus in the form of fluidizing has been described as an example, it is not limited thereto. For example, the low grade coal 101 may be fluidized by conveying the low grade coal 101 while stirring it using a screw feeder.

  As described above, the low-grade coal drying system according to the present invention suppresses wear of the blade of the rotating machine with the dust collector when introducing steam generated when the low-grade coal is dried into the rotating machine. However, it is suitable for preventing clogging of the dust collector.

DESCRIPTION OF SYMBOLS 100 Low grade coal drying system 101 Low grade coal 102 Low grade coal drying apparatus 103 Heat transfer member 104 Generated steam 105 Dust collector 107 Fluidized steam 108 Dry coal 109 Product coal 110 Cooler 111 Fluidized bed 114 Circulating fan 115 Solid component 120 Compressor 121 Pre-dust collection heater 121a Casing 121b Heat transfer member 121c Water spray nozzle 122 Post-dust collection heater 122a Casing 122b Heat transfer member 123 Steam turbine 200 Coal gasification combined power generation system A Superheated steam B Condensed water F Free board part L ₁ generation steam line L ₂ branch line S Wash water

Claims (4)

A low-grade coal drying device that indirectly dries low-grade coal with the latent heat of superheated steam;
A rotating machine into which generated steam generated from the low-grade coal by drying is introduced;
A dust collector that is provided while the generated steam is introduced into the rotary machine from the low-grade coal drying apparatus, and collects particulates contained in the generated steam;
The low-grade coal drying unit is provided while the generated steam is introduced into the dust collector, and the low-grade coal is heated by indirect heat exchange with condensed water condensed by the superheated steam that has dried the low-grade coal. A pre-dust collection heater for heating the generated steam before reaching the dust collector from a graded coal dryer;
The pre-dust collection heater includes a casing through which the generated steam passes, a tubular heat transfer member provided in the casing and supplied with the condensed water, and the heat transfer member in the casing. A low-grade coal drying system comprising a water spray nozzle that sprays wash water to the outside . From the dust collector by indirect heat exchange with the condensed water condensed by the superheated steam that is provided while the generated steam is introduced from the dust collector into the rotary machine and dried the low-grade coal. The low-grade coal drying system according to claim 1 , further comprising a post-dust collection heater that heats the generated steam before reaching the rotating machine. The low-grade coal drying system according to claim 1 or 2 , wherein the rotating machine is a compressor that compresses the generated steam generated from the low-grade coal by drying into high-temperature and high-pressure superheated steam. . The low-grade coal drying system according to claim 1 or 2 , wherein the rotating machine is a steam turbine that is operated using the generated steam generated from the low-grade coal by drying.

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