JP2013170799A - Fluid bed drying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid bed drying device for stable drying by properly heating wet fuel using superheated steam.SOLUTION: A fluid bed drying device includes a drying container 101 which contains a raw coal feeding opening 102 and a dried coal discharging opening 103, a fluidizing steam supply part 104 which forms a fluid bed S along with raw coal by supplying fluidizing steam to the lower part of the drying container 101, and heat transfer pipes 106, 107, and 108 for heating raw coal of the fluid bed S by causing superheated steam to be distributed inside. The heat transfer pipes 106, 107, and 108 are disposed in such a manner as a position of dry degree 0 at which the superheated steam becomes condensed water is positioned on further upper stream side in flow direction of the superheated steam only by a predetermined distance than outlet parts 106b, 107b, and 108b of the fluid bed S.

Description

  The present invention relates to a fluidized bed drying apparatus for drying a material to be dried by fluidizing steam.

  For example, a combined coal gasification power generation facility is a power generation facility that aims to further increase the efficiency and environmental performance compared to conventional coal-fired power generation by gasifying coal and combining it with combined cycle power generation. This coal gasification combined cycle power generation facility has a great merit that it can use coal with abundant resources, and it is known that the merit can be further increased by expanding the applicable coal types.

  Conventional coal gasification combined power generation facilities generally have a coal supply device, a drying device, a coal gasification furnace, a gas purification device, a gas turbine facility, a steam turbine facility, an exhaust heat recovery boiler, a gas purification device, and the like. ing. Therefore, the coal is dried and then pulverized, supplied to the coal gasifier as pulverized coal, and air is taken in. The coal gas is combusted and gasified in this coal gasifier, and the product gas (combustible) Gas) is produced. Then, the product gas is purified and then supplied to the gas turbine equipment to burn and generate high-temperature and high-pressure combustion gas to drive the turbine. The exhaust gas after driving the turbine recovers thermal energy by the exhaust heat recovery boiler, generates steam and supplies it to the steam turbine equipment, and drives the turbine. As a result, power generation is performed. On the other hand, the exhaust gas from which the thermal energy has been recovered is released into the atmosphere through a chimney after harmful substances are removed by the gas purification device.

  By the way, the coal used in such a coal gasification combined power generation facility is not only a high-grade coal (high-grade coal) having a high calorific value such as bituminous coal and anthracite, but also a comparison such as sub-bituminous coal and lignite. There is a low-grade coal (low-grade coal) with a low calorific value. This low-grade coal has a large amount of moisture to be brought in, and the power generation efficiency decreases due to this moisture. For this reason, in the case of low-grade coal, it is necessary to dry the coal with the above-described drying apparatus to remove moisture and then pulverize and supply the coal gasifier.

  As a drying apparatus for drying such coal, there is one described in Patent Document 1 below. In the vibrating fluidized bed apparatus described in Patent Documents 1 and 2, a large number of heating tubes are arranged in the fluidized bed, and superheated steam is supplied into the heating tubes to heat and dry the raw material. .

Japanese Patent Laid-Open No. 06-323724 JP 60-106880 A

  In the conventional drying apparatus described above, a heat transfer tube (heating tube) is disposed in the fluidized bed, and the raw material is heated and dried by supplying superheated steam into the heat transfer tube. In this case, although the superheated steam supplied to the heat transfer tube has a dryness (quality) of 1 at the inlet of the fluidized bed, it condenses and liquefies while heating the raw material, and at the outlet of the fluidized bed A dryness of 0 is desirable for effective use of heat. By the way, if the properties of the raw material change during the operation of the drying device or the drying state in the fluidized bed fluctuates, the heat transfer coefficient between the heat transfer tube (superheated steam) and the raw material decreases, and the sufficient amount of raw material It becomes difficult to perform heating. That is, the raw material cannot receive sufficient heat from the superheated steam and cannot obtain sufficient dryness, while the superheated steam cannot be completely condensed and liquefied, The dryness does not become 0 at the outlet, and the heat is not effectively used.

  The present invention solves the above-described problems, and an object of the present invention is to provide a fluidized bed drying apparatus that enables stable drying by appropriately heating wet fuel with superheated steam.

  In order to achieve the above object, the fluidized bed drying apparatus according to the present invention is capable of supplying wet fuel from the wet fuel supply section on one end side and drying the wet fuel heated and dried from the dry matter discharge section on the other end side. A hollow container capable of discharging an object, a fluidized steam supply part that forms a fluidized bed with wet fuel by supplying fluidized steam to the drying container, and circulating superheated steam inside A heat transfer tube that heats the wet fuel in the fluidized bed, wherein the heat transfer tube has a position of 0 degree of dryness where the superheated steam becomes condensed water, and the flow direction of the superheated steam by a predetermined length from the outlet of the fluidized bed. It is arrange | positioned so that it may be located in the upstream of this.

  Accordingly, the fluidized steam supply unit supplies the fluidized steam to the fluidized bed of the drying container and distributes the superheated steam in the heat transfer tube, whereby the wet fuel constituting the fluidized bed is heated and dried. . At this time, when the drying operation state is normal, heat can be appropriately applied to the wet fuel in a predetermined region, so that the superheated steam supplied into the heat transfer tube has a dryness of 0. That is, condensed water is discharged at a position upstream by a predetermined length from the outlet of the fluidized bed, and the wet fuel can be properly dried. On the other hand, when the drying operation state is lowered, heat cannot be properly applied to the wet fuel in a predetermined region, but the position where the dryness of the superheated steam becomes 0 shifts to the outlet portion side of the fluidized bed. Therefore, the effective heat transfer area is increased, and the wet fuel can be dried appropriately. As a result, stable drying can be achieved by appropriately heating the wet fuel with superheated steam.

  In the fluidized bed drying apparatus of the present invention, the heat transfer tube is disposed in the fluidized bed, one end is connected to the inlet of the fluidized bed, and the other end is connected to the outlet of the fluidized bed, Drying of superheated steam into condensed water under normal operating conditions where the temperature, pressure and supply of fluidized steam and the temperature, pressure and supply of superheated steam are set relative to the properties and supply of wet fuel The length of the heat transfer tube is set so that the position of 0 degree is positioned upstream of the outlet portion in the flow direction of the superheated steam by a predetermined length.

  Therefore, the length of the heat transfer tube is set to be long so that the position of the dryness 0 where the superheated steam becomes condensed water is positioned upstream of the outlet portion in the flow direction of the superheated steam under the standard operating conditions. In addition, by securing a surplus heating area by the heat transfer tube here, even if the drying operation state fluctuates, it is possible to stably carry out the heating and drying of the wet fuel by the superheated steam at all times.

  In the fluidized bed drying apparatus of the present invention, a superheated steam supply amount adjusting device capable of changing the supply amount of superheated steam is provided, and when the drying operation state is lowered, the superheated steam supply amount adjusting device is configured to superheat the heat transfer tube. It is characterized by increasing the supply amount of steam.

  Therefore, by increasing the amount of superheated steam supplied to the heat transfer tube when the drying operation state is lowered, the drying operation state can be quickly restored to the normal state.

  According to the fluidized bed drying apparatus of the present invention, the position of the degree of dryness 0 at which the superheated steam in the heat transfer tube becomes condensed water is located upstream of the outlet of the fluidized bed by a predetermined length in the flow direction of the superheated steam. Thus, since the heat transfer tube is arranged, stable drying can be achieved by appropriately heating the wet fuel with the superheated steam.

FIG. 1 is a schematic side view showing a fluidized bed drying apparatus according to an embodiment of the present invention. FIG. 2 is a schematic rear view showing the fluidized bed drying apparatus of the present embodiment. FIG. 3 is a schematic configuration diagram showing the flow of fluidized steam in the fluidized bed drying apparatus of the present embodiment. FIG. 4 is an explanatory view showing the dryness of the fluidized steam in the heat transfer tube in the fluidized bed drying apparatus of the present embodiment. FIG. 5 is a schematic configuration diagram of a combined coal gasification combined power generation facility to which the fluidized bed drying apparatus of the present embodiment is applied.

  Exemplary embodiments of a fluidized bed drying apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

  FIG. 1 is a schematic side view showing a fluidized bed drying apparatus according to an embodiment of the present invention, FIG. 2 is a schematic rear view showing a fluidized bed drying apparatus of the present embodiment, and FIG. 3 is a fluidized bed of the present embodiment. 4 is a schematic configuration diagram showing the flow of fluidized steam in the drying apparatus, FIG. 4 is an explanatory diagram showing the dryness of the fluidized steam in the heat transfer tube in the fluidized bed drying apparatus of the present embodiment, and FIG. It is a schematic block diagram of the coal gasification combined cycle power generation facility to which the fluidized bed drying apparatus was applied.

  The coal gasification combined power generation facility (IGCC: Integrated Coal Gasification Combined Cycle) of the present embodiment adopts an air combustion method in which coal gas is generated in a gasification furnace using air as an oxidizer and is purified by a gas purification device. Coal gas is supplied as fuel gas to gas turbine equipment to generate electricity. That is, the combined coal gasification combined power generation facility of this embodiment is a power generation facility of an air combustion system (air blowing). In this case, low-grade coal is used as the wet fuel supplied to the gasifier.

  In this embodiment, as shown in FIG. 5, the coal gasification combined power generation facility 10 includes a coal supply device 11, a fluidized bed drying device 12, a pulverized coal machine (mill) 13, a coal gasification furnace 14, and a char recovery device 15. , A gas refining device 16, a gas turbine facility 17, a steam turbine facility 18, a generator 19, and a heat recovery steam generator (HRSG) 20.

  The coal feeder 11 includes a raw coal bunker 21, a coal feeder 22, and a crusher 23. The raw coal bunker 21 can store low-grade coal, and can drop a predetermined amount of low-grade coal into the coal feeder 22. The coal feeder 22 can transport the low-grade coal dropped from the raw coal bunker 21 by a conveyor or the like and drop it on the crusher 23. The crusher 23 can crush the dropped low-grade coal into a predetermined size.

  The fluidized bed drying device 12 supplies drying steam (superheated steam) to the low-grade coal introduced by the coal feeder 11 so as to heat and dry the low-grade coal while flowing. Moisture contained in the graded coal can be removed. The fluidized bed drying device 12 is provided with a cooler 31 for cooling the dried low-grade coal taken out from the lower portion, and the dried and cooled dried coal is stored in the dried coal bunker 32. Further, the fluidized bed drying apparatus 12 is provided with a dry coal cyclone 33 and a dry coal electrostatic precipitator 34 for separating dry coal particles from steam taken out from above, and the dry coal particles separated from the steam are dried coal bunker. 32 is stored. The steam from which the dry coal has been separated by the dry coal electrostatic precipitator 34 is compressed by the steam compressor 35 and then supplied to the fluidized bed drying device 12 as drying steam.

  The pulverized coal machine 13 is a coal pulverizer, and pulverizes the low-grade coal (dried coal) dried by the fluidized bed dryer 12 into fine particles to produce pulverized coal. That is, in the pulverized coal machine 13, the dry coal stored in the dry coal bunker 32 is dropped by the coal feeder 36, and the dry coal is converted into low-grade coal having a predetermined particle size or less, that is, pulverized coal. The pulverized coal after being pulverized by the pulverized coal machine 13 is separated from the conveying gas by the pulverized coal bag filters 37a and 37b and stored in the pulverized coal supply hoppers 38a and 38b.

  The coal gasification furnace 14 can supply pulverized coal processed by the pulverized coal machine 13 and can be recycled by returning the char (unburned coal) recovered by the char recovery device 15. .

  That is, the coal gasification furnace 14 is connected to the compressed air supply line 41 from the gas turbine equipment 17 (compressor 61), and can supply compressed air compressed by the gas turbine equipment 17. The air separation device 42 separates and generates nitrogen and oxygen from air in the atmosphere. A first nitrogen supply line 43 is connected to the coal gasifier 14, and a pulverized coal supply hopper is connected to the first nitrogen supply line 43. Charging lines 44a and 44b from 38a and 38b are connected. The second nitrogen supply line 45 is also connected to the coal gasification furnace 14, and the char return line 46 from the char recovery device 15 is connected to the second nitrogen supply line 45. Further, the oxygen supply line 47 is connected to the compressed air supply line 41. In this case, nitrogen is used as a carrier gas for coal and char, and oxygen is used as an oxidant.

  The coal gasification furnace 14 is, for example, a spouted bed type gasification furnace, which combusts and gasifies coal, char, air (oxygen) supplied therein or water vapor as a gasifying agent, and produces carbon dioxide. A combustible gas (product gas, coal gas) containing carbon as a main component is generated, and a gasification reaction takes place using this combustible gas as a gasifying agent. The coal gasification furnace 14 is provided with a foreign matter removing device 48 that removes foreign matter mixed with pulverized coal. In this case, the coal gasification furnace 14 is not limited to the spouted bed gasification furnace, and may be a fluidized bed gasification furnace or a fixed bed gasification furnace. The coal gasification furnace 14 is provided with a gas generation line 49 for combustible gas toward the char recovery device 15, and can discharge combustible gas containing char. In this case, by providing a gas cooler in the gas generation line 49, the combustible gas may be cooled to a predetermined temperature and then supplied to the char recovery device 15.

  The char recovery device 15 includes a dust collector 51 and a supply hopper 52. In this case, the dust collector 51 is constituted by one or a plurality of bag filters or cyclones, and can separate char contained in the combustible gas generated in the coal gasification furnace 14. The combustible gas from which the char has been separated is sent to the gas purification device 16 through the gas discharge line 53. The supply hopper 52 stores the char separated from the combustible gas by the dust collector 51. A bin may be disposed between the dust collector 51 and the supply hopper 52, and a plurality of supply hoppers 52 may be connected to the bin. A char return line 46 from the supply hopper 52 is connected to the second nitrogen supply line 45.

The gas purification device 16 performs gas purification by removing impurities such as sulfur compounds and nitrogen compounds from the combustible gas from which the char has been separated by the char recovery device 15. The gas purifier 16 purifies the combustible gas to produce fuel gas and supplies it to the gas turbine equipment 17. In the gas purifier 16, since the combustible gas from which the char is separated still contains sulfur (H ₂ S), the sulfur is finally removed by removing it with the amine absorbent. Is recovered as gypsum and used effectively.

  The gas turbine equipment 17 includes a compressor 61, a combustor 62, and a turbine 63, and the compressor 61 and the turbine 63 are connected by a rotating shaft 64. The combustor 62 has a compressed air supply line 65 connected to the compressor 61, a fuel gas supply line 66 connected to the gas purifier 16, and a combustion gas supply line 67 connected to the turbine 63. Further, the gas turbine equipment 17 is provided with a compressed air supply line 41 extending from the compressor 61 to the coal gasification furnace 14, and a booster 68 is provided in the middle. Therefore, in the combustor 62, the compressed air supplied from the compressor 61 and the fuel gas supplied from the gas purifier 16 are mixed and burned, and the rotating shaft 64 is rotated by the generated combustion gas in the turbine 63. By doing so, the generator 19 can be driven.

  The steam turbine facility 18 includes a turbine 69 that is coupled to the rotating shaft 64 in the gas turbine facility 17, and the generator 19 is coupled to the base end portion of the rotating shaft 64. The exhaust heat recovery boiler 20 is provided in the exhaust gas line 70 from the gas turbine equipment 17 (the turbine 63), and generates steam by exchanging heat between the air and the high temperature exhaust gas. Therefore, the exhaust heat recovery boiler 20 is provided with the steam supply line 71 between the steam turbine equipment 18 and the turbine 69 of the steam turbine equipment 18, the steam recovery line 72 is provided, and the steam recovery line 72 is provided with the condenser 73. Yes. Therefore, in the steam turbine facility 18, the turbine 69 is driven by the steam supplied from the exhaust heat recovery boiler 20, and the generator 19 can be driven by rotating the rotating shaft 64.

  The exhaust gas from which heat has been recovered by the exhaust heat recovery boiler 20 is freed of harmful substances by the gas purification device 74, and the purified exhaust gas is discharged from the chimney 75 to the atmosphere.

  Here, the action | operation of the coal gasification combined cycle power generation equipment 10 of a present Example is demonstrated.

  In the coal gasification combined power generation facility 10 of the present embodiment, raw coal (low-grade coal) is stored in the raw coal bunker 21 by the coal feeder 11, and the low-grade coal of the raw coal bunker 21 is supplied to the coal. The machine 22 drops the crusher 23 where it is crushed to a predetermined size. The crushed low-grade coal is heated and dried by the fluidized bed drying device 12, cooled by the cooler 31, and stored in the dry coal bunker 32. Further, the steam taken out from the upper part of the fluidized bed drying device 12 is separated into dry coal particles by the dry coal cyclone 33 and the dry coal electrostatic precipitator 34 and compressed by the steam compressor 35 before being supplied to the fluidized bed drying device 12. Returned as drying steam. On the other hand, the dry coal particles separated from the steam are stored in the dry coal bunker 32.

  The dry coal stored in the dry coal bunker 32 is fed into the pulverized coal machine 13 by the coal feeder 36, where it is pulverized into fine particles to produce pulverized coal, and through the pulverized coal bag filters 37a and 37b. And stored in the pulverized coal supply hoppers 38a and 38b. The pulverized coal stored in the pulverized coal supply hoppers 38 a and 38 b is supplied to the coal gasification furnace 14 through the first nitrogen supply line 43 by nitrogen supplied from the air separation device 42. Further, the char recovered by the char recovery device 15 described later is supplied to the coal gasifier 14 through the second nitrogen supply line 45 by nitrogen supplied from the air separation device 42. Further, the compressed air extracted from the gas turbine equipment 17 to be described later is boosted by the booster 68 and then supplied to the coal gasification furnace 14 through the compressed air supply line 41 together with oxygen supplied from the air separation device 42.

  In the coal gasification furnace 14, the supplied pulverized coal and char are combusted by compressed air (oxygen), and the pulverized coal and char are gasified to generate combustible gas (coal gas) mainly composed of carbon dioxide. Can be generated. The combustible gas is discharged from the coal gasifier 14 through the gas generation line 49 and sent to the char recovery device 15.

  In the char recovery device 15, the combustible gas is first supplied to the dust collector 51, whereby the char contained in the gas is separated from the combustible gas. The combustible gas from which the char has been separated is sent to the gas purification device 16 through the gas discharge line 53. On the other hand, the fine char separated from the combustible gas is deposited on the supply hopper 52, returned to the coal gasifier 14 through the char return line 46, and recycled.

  The combustible gas from which the char has been separated by the char recovery device 15 is subjected to gas purification by removing impurities such as sulfur compounds and nitrogen compounds in the gas purification device 16 to produce fuel gas. In the gas turbine facility 17, when the compressor 61 generates compressed air and supplies the compressed air to the combustor 62, the combustor 62 is supplied from the compressed air supplied from the compressor 61 and the gas purification device 16. Combustion gas is generated by mixing with fuel gas and combusting, and the turbine 63 is driven by this combustion gas, so that the generator 19 can be driven via the rotating shaft 64 to generate power.

  The exhaust gas discharged from the turbine 63 in the gas turbine equipment 17 generates steam by exchanging heat with air in the exhaust heat recovery boiler 20, and supplies the generated steam to the steam turbine equipment 18. . In the steam turbine facility 18, the generator 69 can be driven through the rotating shaft 64 to generate electric power by driving the turbine 69 with the steam supplied from the exhaust heat recovery boiler 20.

  Thereafter, in the gas purification device 74, harmful substances in the exhaust gas discharged from the exhaust heat recovery boiler 20 are removed, and the purified exhaust gas is discharged from the chimney 75 to the atmosphere.

  Hereinafter, the fluidized bed drying apparatus 12 in the coal gasification combined power generation facility 10 described above will be described in detail.

  The fluidized bed drying apparatus 12 is a plug flow type drying apparatus, and as shown in FIGS. 1 and 2, a drying container 101, a raw coal charging port 102, a dry coal discharging port 103, and a fluidized steam supply. The unit 104 (104a, 104b, 104c), the gas discharge port 105, and the heat transfer tubes 106, 107, 108 are provided.

  The drying container 101 has a hollow box shape, and a raw coal charging port 102 for charging raw coal is formed on one end side, and a dried product obtained by heating and drying raw coal is discharged to the lower portion on the other end side. A dry charcoal discharge port 103 is formed. In this case, the raw coal input port 102 and the dry coal discharge port 103 are provided one by one at the end of the drying container 101, but a plurality of them may be provided. In this case, the drying container 101 can adjust the amount of raw coal supplied from the raw coal inlet 102 to the inside by the coal feeder 22 (see FIG. 5). Moreover, the dry container 101 can adjust raw coal discharge | emission amount by adjusting the rotation speed of the rotary valve which is not shown in the dry charcoal discharge port 103 provided.

  Further, the drying container 101 is provided with a dispersion plate 109 having a plurality of openings at a predetermined distance from the bottom plate 101a in the lower portion, so that the wind box 110 is partitioned. The drying container 101 is provided with a fluidized steam supply unit 104 (104a, 104b, 104c) that supplies fluidized steam (superheated steam) to the bottom plate 101a via the wind box 110 and above the dispersion plate 109. Yes. Further, in the drying container 101, a gas discharge port 105 for discharging fluidized steam and generated steam is formed in the ceiling plate 101b on the dry coal discharge port 103 side.

  The drying vessel 101 is supplied with raw coal from the raw coal inlet 102 and fluidized steam is supplied from the fluidized steam supply unit 104 through the wind box 110 and the dispersion plate 109, so that the dispersion plate 109 A fluidized bed S having a predetermined thickness is formed above, and a free board portion F is formed above the fluidized bed S.

  The drying container 101 includes a first drying chamber 111 provided on the upstream side in the flow direction of the raw coal, a second drying chamber 112 provided on the downstream side of the first drying chamber 111, and raw coal. And the third drying chamber 113 provided on the most downstream side in the flow direction.

  More specifically, in the drying container 101, the fluidized bed S is divided into a plurality of (in this embodiment, two) partition plates 114 and 115 in the flow direction of the raw coal. Charcoal passage openings 116 and 117 are formed. The partition plates 114 and 115 are arranged along a vertical direction orthogonal to the flow direction of the raw coal, and are arranged at predetermined intervals in the flow direction of the raw coal. It is attached to the inner wall surface. And each partition plate 114,115 is located so that a lower end part may be located in the dispersion plate 109 with a predetermined clearance, and an upper end part may be extended upwards from the fluidized bed S. FIG. That is, passage openings 116 and 117 having a predetermined height and width (opening area) are secured between the partition plates 114 and 115 and the dispersion plate 109, and the passage openings 116 and 117 are substantially The same opening area is set.

  As described above, the drying container 101 is divided into the first drying chamber 111, the second drying chamber 112, and the third drying chamber 113 by providing the partition plates 114 and 115. The drying chambers 111, 112, and 113 are In addition, communication is made above the partition plates 114 and 115. In this case, the first drying chamber 111 is a region (preheat drying region) in which the freeboard portion F1 and the fluidized bed S1 are formed and the initial drying of the raw coal is performed. In the second drying chamber 112, a free board portion F2 and a fluidized bed S2 are formed, and the second drying chamber 112 is an area (fixed rate drying area) where the raw coal is dried in the middle period. In the third drying chamber 113, a free board portion F3 and a fluidized bed S3 are formed, and the third drying chamber 113 is a region where the latter drying of raw coal is performed (decrease rate drying region).

  In this case, each of the drying chambers 111, 112, and 113 is set so that the floor area is substantially the same, but may be set to an optimum ratio according to the moisture content of raw coal, for example, 2 It is desirable to set the floor area of the drying chamber 112 to the maximum. That is, the first drying chamber 111 is a preheat drying region in which the drying rate of the raw coal is increased to a predetermined moisture content because the moisture content of the raw coal to be charged is high. Since the drying rate of the raw coal rises to a predetermined drying rate and becomes constant, the second drying chamber 112 is a constant rate drying region where the drying rate of the raw coal becomes constant. The drying rate of the raw coal is lowered when the moisture content of the raw coal reaches a predetermined moisture content (limit moisture content). Therefore, the third drying chamber 113 is a reduction rate drying region in which the drying rate of the raw coal decreases. is there. Therefore, the drying efficiency is improved by maximizing the volume of the second drying chamber 112 that is the constant rate drying region.

  The wind box 110 is divided into three wind boxes 110a, 110b, and 110c by partition members 118 and 119 so as to correspond to the three drying chambers 111, 112, and 113, and the three wind boxes 110a, 110b, Three fluidized steam supply sections 104a, 104b, and 104c are provided so as to correspond to 110c. That is, the partition members 118 and 119 are disposed below the partition plates 114 and 115. The fluidized steam supply units 104a, 104b, and 104c are connected to a fluidized steam supply pipe (not shown). By adjusting the opening of the flow rate adjustment valve provided in the fluidized steam supply pipe, the wind box The amount of fluidized steam supplied to 110a, 110b, 110c can be adjusted.

  That is, the drying container 101 is configured as a plug flow system so that the supplied raw coal is pushed out in the room. This extruding flow is a flow for extruding the raw coal in the fluidizing direction so that the raw coal does not diffuse in the fluidizing direction in the fluidized bed S.

  Further, the drying container 101 is provided with a plurality of heat transfer tubes 106, 107, and 108 that pass through the drying container 101 from the outside and circulate in the fluidized beds S1, S2, and S3 in the drying chambers 111, 112, and 113, respectively. Has been. The heat transfer tubes 106, 107, 108 are positioned so as to be embedded in the fluidized beds S1, S2, S3, and the raw coals of the fluidized beds S1, S2, S3 are formed by fluidized steam (superheated steam) flowing inside. Can be dried by heating. In this case, the temperature of the heat transfer tubes 106, 107, 108 can be adjusted by changing the pressure of the supplied superheated steam.

  Therefore, the raw coal supplied to the first drying chamber 111 is fluidized by the fluidized steam and heated by the heat transfer tube 106 to be dried. The raw coal initially dried in the first drying chamber 111 is moved to the second drying chamber 112 through the passage opening 116 below the partition plate 114, and is heated by the heat transfer tube 107 here. Medium-term dry. The raw coal dried in the second drying chamber 112 is moved to the third drying chamber 113 through the passage opening 117 at the bottom of the partition plate 115, where it is heated by the heat transfer tube 108. Late drying.

  Thereby, the raw coal forming the fluidized beds S1, S2, and S3 of the drying chambers 111, 112, and 113 sequentially moves between the fluidized beds S1, S2, and S3 from the upstream side through the passage openings 116 and 117. By doing so, it can be made an extruded flow, and it is dried without being diffused in the flow direction.

  Further, as shown in FIG. 3, the fluidized bed drying apparatus 12 is provided with a first steam supply line 121 for supplying fluidized steam (superheated steam) to each of the drying chambers 111, 112, and 113. Three branch lines 121a, 121b, 121c branched from the first steam supply line 121 are connected to the wind boxes 110a, 110b, 110c, respectively. In addition, the fluidized bed drying apparatus 12 is provided with a second steam supply line 122 that supplies superheated steam to the heat transfer tubes 106, 107, and 108 in the drying chambers 111, 112, and 113. Branch lines 122a, 122b, 122c branched from 122 are connected to one end portions (inlet portions) of the respective heat transfer tubes 106, 107, 108.

  In the fluidized bed drying device 12, a gas discharge line 123 is connected to the gas discharge port 105, and a dust removing device 124 is attached to the gas discharge line 123. The gas discharge line 123 is connected to the base end portion of the first steam supply line 121, the base end portion of the second steam supply line 122, and the surplus gas line 126 via the branch portion 125. The first steam supply line 121 is equipped with a heater 127 and a flow rate adjustment valve 128, and the second steam supply line 122 is equipped with a booster 129 and a flow rate adjustment valve 130.

  In addition, drain pipes 131a, 131b, and 131c are connected to the other end portions (outlet portions) of the heat transfer tubes 106, 107, and 108, respectively.

  Accordingly, fluidized steam (superheated steam) is supplied from the first steam supply line 121 to the wind boxes 110a, 110b, and 110c through the branch lines 121a, 121b, and 121c, and from the wind boxes 110a, 110b, and 110c to the drying chambers. 111, 112, 113. The fluidized steam supplied to the drying chambers 111, 112, 113 and the steam generated by drying the raw coal are discharged from the gas discharge port 105 to the gas discharge line 123 and are removed by the dust removing device 124. Thereafter, a part is heated by the heater 127 in the first steam supply line 121, and a part is boosted by the booster 129 in the second steam supply line 122.

  Thereafter, the fluidized steam heated by the heater 127 in the first steam supply line 121 is again supplied from the branch lines 121a, 121b, and 121c to the drying chambers 111, 112, and 113 through the wind boxes 110a, 110b, and 110c. To be supplied. The fluidized steam boosted by the booster 129 in the second steam supply line 122 is supplied as superheated steam from the second steam supply line 122 to the heat transfer tubes 106, 107, and 108 through the branch lines 122a, 122b, and 122c. Then, after the raw coal in each of the drying chambers 111, 112, and 113 is heated, it becomes condensed water and is discharged to the drain pipes 131a, 131b, and 131c.

  In the fluidized bed drying apparatus 12, a thermometer 132 that detects the temperature of the dry coal is disposed at the dry coal discharge port 103. Instead of the thermometer 132 that detects the temperature of the dry coal discharged from the dry coal discharge port 103, a moisture meter that detects the moisture content of the dry coal may be arranged. The control device 133 receives the temperature of the dry coal detected by the thermometer 132 (or the moisture content of the dry coal measured by the moisture meter), and based on the temperature of the dry coal (or the moisture content of the dry coal). The amount of superheated steam supplied to the drying chambers 111, 112, 113 can be adjusted by changing the opening of the flow rate adjustment valve 128. In addition, the control device 133 adjusts the amount of superheated steam supplied to the heat transfer tubes 106, 107, and 108 by changing the opening degree based on the temperature of the dry coal (or the flow rate adjustment valve 130, the moisture content of the dry coal). It is possible.

  By the way, in such a fluidized bed drying apparatus 12, the heat transfer tubes 106, 107, 108 supply superheated steam as fluidized steam to the inside, and thereby heat of the superheated steam is transferred to the heat transfer tubes 106, 107, 108. It is applied to raw coal and dried. In this case, the superheated steam supplied to the heat transfer tubes 106, 107, and 108 has a dryness (quality) of 1 at the inlets of the fluidized beds S1, S2, and S3, and the fluidized beds S1, S2, and S3 are raw materials. While the charcoal is heated, it condenses and liquefies, changes to saturated steam and wet steam (mixed steam of saturated steam and saturated water) to become condensed water (saturated water), and the dryness at the outlet of the fluidized bed Becomes 0. That is, the superheated steam supplied to the heat transfer tubes 106, 107, 108 becomes condensed water by giving all heat to the raw coal in the fluidized beds S1, S2, S3, and efficient drying is possible. ing. However, if the properties of the raw coal change during the drying operation, or if the drying state in the fluidized beds S1, S2, and S3 changes, the heat transfer between the superheated steam in the heat transfer tubes 106, 107, and 108 and the raw coal is transferred. A thermal coefficient falls and it becomes difficult to fully heat a raw material.

  Therefore, in this embodiment, as shown in FIG. 4, the heat transfer tubes 106, 107, 108 are located at the position “a” having a dryness of 0 where the superheated steam becomes condensed water, and the outlet portions 106 b of the fluidized beds S 1, S 2, S 3. , 107b, 108b are arranged so as to be positioned upstream of the superheated steam in the flow direction by a predetermined length.

  That is, the heat transfer tubes 106, 107, 108 are arranged in the fluidized beds S1, S2, S3, respectively, one end is connected to the inlets 106a, 107a, 108a of the fluidized beds S1, S2, S3, and the other end is connected. The fluidized beds S1, S2, and S3 are connected to the outlet portions 106b, 107b, and 108b, the second steam supply line 122 (branch lines 122a, 122b, and 122c) is connected to the inlet portions 106a, 107a, and 108a, and the outlet portions 106b, Drain pipes 131a, 131b, 131c are connected to 107b, 108b. The fluidized bed drying apparatus 12 is configured such that the temperature, pressure, and supply amount of fluidized steam, and the temperature, pressure, and supply amount of superheated steam are set with respect to the properties and supply amount of raw coal as reference operating conditions. Yes. Under this standard operating condition, the position of the degree of dryness 0 where the superheated steam becomes condensed water in the heat transfer tubes 106, 107, 108 is upstream of the outlet portion 106b, 107b, 108b in the flow direction of the superheated steam by a predetermined length. The lengths of the heat transfer tubes 106, 107, and 108 are set so as to be located at

  More specifically, when the entire length (in practice, the region) of the heat transfer tubes 106, 107, 108 is set to A, the superheated steam region A1 is set on the inlet portion 106a, 107a, 108a side. By setting the completely condensed water region A2 on the outlet portions 106b, 107b, 108b side, the position a where the dryness of the superheated steam becomes 0 is set. In this case, it is desirable to set the completely condensed water region A2 to about 10% of the entire region A of the heat transfer tubes 106, 107, and 108.

  Therefore, when the fluidized bed drying apparatus 12 is operating normally under preset reference operating conditions, the superheated steam supplied to the inlet portions 106a, 107a, 108a of the heat transfer tubes 106, 107, 108 is the heat transfer tube 106. , 107 and 108, the raw coal is cooled by being heated, and at a position a between the superheated steam region A1 and the completely condensed water region A2, the dryness becomes 0 and becomes condensed water. That is, the dryness of the superheated steam decreases as X1.

  On the other hand, when the fluidized bed drying apparatus 12 is not operating normally under the standard operating conditions, the superheated steam supplied to the inlet portions 106a, 107a, 108a of the heat transfer tubes 106, 107, 108 is the heat transfer tubes 106, 107, 108. Although it is cooled by heating the raw coal during circulation, since sufficient heat cannot be imparted to the raw coal, at a position a between the superheated steam region A1 and the fully condensed water region A2, Dryness does not become zero. That is, the position a where the degree of dryness of the superheated steam becomes 0 shifts to the outlet portions 106b, 107b, 108b, so that the superheated steam area A1 increases and the fully condensed water area A2 decreases. That is, the degree of dryness of the superheated steam decreases, for example, as X2. Actually, when the dry state of the raw coal by the fluidized bed dryer 12 is lowered, the dryness of the superheated steam varies between X1 and X2.

  Further, when the drying operation state in the fluidized bed drying device 12 is lowered, the control device (superheated steam supply amount adjusting device) increases the opening degree of the flow rate adjusting valve 130 to the heat transfer tubes 106, 107, 108. Increase the amount of superheated steam supply.

  Here, the entire operation of the fluidized bed drying apparatus 12 of the present embodiment will be described.

  In the fluidized bed drying device 12, as shown in FIGS. 1 and 2, the raw coal is supplied from the raw coal inlet 102 to the drying container 101 and flows from the fluidized steam supply unit 104 through the dispersion plate 109. When the vaporized steam is supplied, fluidized beds S1, S2, and S3 having a predetermined thickness are formed above the dispersion plate 109. The raw coal moves through the fluidized beds S1, S2, and S3 to the dry coal discharge port 103 side by the fluidized steam, and at this time, the raw coal is heated and dried by receiving heat from the heat transfer tubes 106, 107, and 108.

  That is, when raw coal is supplied from the raw coal inlet 102, first, in the first drying chamber 111, fluidized steam is supplied from the fluidized steam supply unit 104 a through the dispersion plate 109, and heat is transferred from the heat transfer tube 106. By receiving, it is dried while flowing in the fluidized bed S1. Next, the raw coal that has been initially dried in the first drying chamber 111 flows into the second drying chamber 112 through the passage opening 116 of the partition plate 114. In the second drying chamber 112, fluidized steam is supplied from the fluidized steam supply unit 104 b through the dispersion plate 109 and receives heat from the heat transfer tube 107, so that it is dried while flowing in the fluidized bed S <b> 2. The raw coal that has been subjected to medium-term drying in the second drying chamber 112 flows into the third drying chamber 113 through the passage opening 117 of the partition plate 115. In the third drying chamber 113, fluidized steam is supplied from the fluidized steam supply unit 104c through the dispersion plate 109, and is also dried while flowing in the fluidized bed S3 by receiving heat from the heat transfer tube. In this way, the raw coal flows in the fluidized beds S1, S2, S3 by the fluidized steam supplied while being heated by the heat transfer tubes 106, 107, 108, and diffuses in the flow direction as an extruded flow. Without drying.

  At this time, when the fluidized bed drying apparatus 12 is operating normally under preset reference operating conditions, the superheated steam supplied to the inlet portions 106a, 107a, 108a of the heat transfer tubes 106, 107, 108 is transferred to the heat transfer tubes. It cools by heating raw coal while circulating 106,107,108. That is, the superheated steam changes from superheated steam to saturated steam and wet steam (saturated steam and saturated water mixed steam) in the superheated steam region A1, and becomes a condensed water (saturated water) at the position a. It becomes 0 and circulates in the state of condensed water in the completely condensed water region A2. In the completely condensed water region A2, since the heat transfer coefficient is low, it is considered that the amount of heat exchange between the raw coal and the condensed water, that is, the raw coal can hardly be dried by the condensed water.

  On the other hand, due to changes in the properties of raw coal (initial moisture content variation, particle size variation, changes with time in the bed), fluidized steam velocity changes in the fluidized beds S1, S2, S3, etc., the heat transfer tubes 106, 107, When the raw coal flow state in the vicinity of 108 changes, the heat transfer coefficient between the heat transfer tubes 106, 107, 108 and the raw coal, that is, the heat transfer coefficient outside the pipe changes. On the other hand, the heat transfer coefficient inside the heat transfer tubes 106, 107, 108 becomes a large value because it takes the form of condensation heat transfer, and the overall heat transfer coefficient between the raw coal and the superheated steam is governed outside the tube, and the raw coal Strongly affected by fluidity.

  Then, the fluidized bed drying apparatus 12 is not normally operated under the standard operating conditions, and the superheated steam supplied to the inlet portions 106a, 107a, 108a of the heat transfer tubes 106, 107, 108 is the heat transfer tubes 106, 107. , 108, the raw coal is cooled by heating, but the raw coal cannot be properly dried only in the superheated steam region A1. In this case, since the heat transfer coefficient outside the tubes of the heat transfer tubes 106, 107, 108 is reduced, the heat flux of the heat transfer tubes 106, 107, 108 is reduced, and the amount of exchange heat in the superheated steam region A1 is reduced. Then, at the position of point a set in advance, all of the superheated steam does not become condensed water, and the position of this point a shifts to the outlets 106b, 107b, 108b side. Then, part or all of the completely condensed water region A2 becomes the superheated steam region A1, and the overall heat transfer coefficient of the heat transfer tubes 106, 107, 108 increases, and the effective heat transfer area of the heat transfer tubes 106, 107, 108 increases. Increase and return to the exchange heat before the change. Therefore, the fluidized bed drying apparatus 12 can secure a stable and constant exchange heat quantity by increasing the effective heat transfer area of the heat transfer tubes 106, 107, 108 even if the operating conditions fluctuate, and the raw coal Is properly heated and dried.

  Thereafter, the dry coal from which the raw coal has been dried is discharged to the outside through the dry coal discharge port 103, and the steam generated by heating and drying the raw coal in the fluidized bed S rises together with the fluidized steam. It flows to the discharge port 103 side and is discharged from the gas discharge port 105 to the outside.

  Further, when the drying operation state of the fluidized bed drying device 12 is lowered, the control device 133 increases the supply amount of superheated steam to the heat transfer tubes 106, 107, 108 by increasing the opening degree of the flow rate adjustment valve 130. You may make it do.

  As described above, in the fluidized bed drying apparatus of the present embodiment, the raw coal is obtained by supplying fluidized steam to the drying vessel 101 having the raw coal inlet 102 and the dry coal outlet 103 and the lower portion of the drying vessel 101. In addition, a fluidized steam supply unit 104 that forms fluidized beds S1, S2, and S3, and heat transfer tubes 106, 107, and 108 that heat the raw coal of the fluidized bed S by circulating superheated steam therein are provided. The heat pipes 106, 107, and 108 are positioned so that the position of the dryness 0 where the superheated steam becomes condensed water is located upstream of the outlet portions 106 b, 107 b, and 108 b of the fluidized bed S by a predetermined length in the flow direction of the superheated steam. Is arranged.

  Accordingly, the raw coal is heated and dried by supplying the fluidized steam to the fluidized beds S1, S2, and S3 and circulating the superheated steam through the heat transfer tubes 106, 107, and 108. At this time, when the drying operation state is normal, the fluidized steam and the superheated steam in the heat transfer tubes 106, 107, 108 can appropriately impart heat to the raw coal in the superheated steam region A1, so The superheated steam supplied into the heat pipes 106, 107, 108 has a dryness of 0 at a position a upstream from the outlets 106b, 107b, 108b of the fluidized bed by a predetermined length, and is discharged as condensed water. Can be dried properly. On the other hand, when the drying operation state is lowered, heat cannot be appropriately applied to the raw coal in the superheated steam region A1, but the position a where the dryness of the superheated steam becomes 0 is the fluidized bed S1, S2, S3. Since it moves to the exit part 106b, 107b, 108b side, an effective heat-transfer area increases and raw coal can be dried appropriately. As a result, stable drying can be achieved by appropriately heating the raw coal with superheated steam.

  Further, in the fluidized bed drying apparatus of the present embodiment, the superheated steam is located at a position of 0 degree of dryness where the superheated steam becomes condensed water under a predetermined standard operation condition by a predetermined length from the outlet portions 106b, 107b, 108b. The lengths of the heat transfer tubes 106, 107, and 108 are set to be long so as to be located upstream in the flow direction. Accordingly, in the heat transfer tubes 106, 107, 108, the superheated steam region A1 is set on the inlet portion 106a, 107a, 108a side with respect to the entire region A, and the completely condensed water region A2 is set on the outlet portion 106b, 107b, 108b side. By setting the complete condensed water region A2 as a heating surplus region, even if the drying operation state fluctuates, the heating and drying of the raw coal with superheated steam can be performed stably at all times.

  Moreover, in the fluidized bed drying apparatus of the present embodiment, when the drying operation state of the fluidized bed drying apparatus 12 is lowered, the control device 133 increases the opening degree of the flow rate adjustment valve 130, so that the heat transfer tubes 106, 107, The amount of superheated steam supplied to 108 is increased. Therefore, the dry operation state can be quickly restored to the normal state.

  In the embodiment described above, the inside of the drying container 101 is divided into three drying chambers 111, 112, and 113, but may be two drying chambers or four or more drying chambers. Further, the configuration and arrangement of the shape of the drying container 101, the raw coal inlet 102, the dry coal outlet 103, the fluidized steam supply unit 104, the gas outlet 105, and the heat transfer tubes 106, 107, 108 are described in each embodiment. It is not limited and can be changed as appropriate according to the installation location and application of the fluidized bed drying device 12.

  In the above-described embodiments, low-grade coal is used as the wet fuel, but even high-grade coal can be applied, and is not limited to coal, and can be used as a renewable organic organic resource. For example, it is also possible to use thinned wood, waste wood, driftwood, grass, waste, sludge, tires, and recycled fuel (pellets or chips) using these as raw materials.

  In the embodiment described above, the passage openings 116 and 117 are provided in the lower part of the partition plates 114 and 115 in the vertical direction. However, the passage openings 116 and 117 are provided in the middle part of the partition plates 114 and 115 in the vertical direction. However, the position is not limited to the positions of the passage openings 116 and 117.

DESCRIPTION OF SYMBOLS 11 Coal feeder 12 Fluidized bed dryer 13 Pulverized coal machine 14 Coal gasifier 15 Char recovery device 16 Gas refiner 17 Gas turbine equipment 18 Steam turbine equipment 19 Generator 20 Waste heat recovery boiler 101 Drying vessel 102 Raw coal input 103 Dry coal discharge port 104 Fluidized steam supply unit 105 Gas discharge port 106, 107, 108 Heat transfer tube 111 First drying chamber 112 Second drying chamber 113 Third drying chamber 114, 115 Partition plates 116, 117 Passing opening 133 Control Equipment (superheated steam supply adjustment device)
F, F1, F2, F3 Free board part S, S1, S2, S3 Fluidized bed

Claims (3)

A drying container having a hollow shape capable of discharging wet fuel from the wet fuel charging portion on one end side and discharging dry matter obtained by heating and drying the wet fuel from the dry matter discharging portion on the other end side;
A fluidized steam supply unit that forms a fluidized bed with wet fuel by supplying fluidized steam to the drying vessel;
A heat transfer tube for heating the wet fuel in the fluidized bed by circulating superheated steam inside,
With
The heat transfer tube is disposed so that the position of the dryness 0 where the superheated steam becomes condensed water is positioned upstream of the outlet direction of the fluidized bed by a predetermined length in the flow direction of the superheated steam.
A fluidized bed drying apparatus.   The heat transfer tube is disposed in the fluidized bed, one end is connected to the inlet of the fluidized bed, the other end is connected to the outlet of the fluidized bed, and the wet fuel properties and supply amount The position of the degree of dryness at which the superheated steam becomes condensed water under the standard operating conditions in which the temperature, pressure and supply amount of the fluidized steam and the temperature, pressure and supply amount of the superheated steam are set is The fluidized bed drying apparatus according to claim 1, wherein the length of the heat transfer tube is set so as to be positioned upstream of the superheated steam in the flow direction by a predetermined length.   A superheated steam supply amount adjustment device capable of changing the supply amount of superheated steam is provided, and when the drying operation state decreases, the superheated steam supply amount adjustment device increases the supply amount of superheated steam to the heat transfer tube. The fluidized bed drying apparatus according to claim 1 or 2.

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