JP2011214817A - Fluidized bed drying device and fluidized bed drying facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidized bed drying device and a fluidized bed drying facility accelerating fluidization by carrying out favorable mixing in the fluidized bed drying device.SOLUTION: The fluidized bed drying device fluidizing and drying a drying object supplied into a drying chamber by supplying fluidizing gas into the drying chamber includes a crusher 130 crushing the drying object (brown coal) 101 to a predetermined particle diameter (about an average particle diameter of several millimeters); a first flowing chamber 132A dividing an interior of the fluidized bed drying device 102 by a wall 131, supplying the crushed drying object 101, and starting flowing/drying; a second flowing chamber 132B carrying out overflow of fine particles flown/dried by the first flowing chamber 132A to further carry out flowing/drying; and a conveyance line Lconveying coarse particles 133 delivered from the first flowing chamber 132A to a crusher 130 side.

Description

  The present invention relates to a fluidized bed drying apparatus that dries a material to be dried with a fluidized gas, and particularly relates to a fluidized bed drying device and a fluidized bed drying facility that can take measures against poor flow of the material to be dried.

  For example, a combined coal gasification power generation facility is a power generation facility that aims at further higher efficiency and higher environmental performance than conventional coal-fired power 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. 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, such a fluidized bed drying apparatus for drying coal includes a drying chamber which is a dispersible plate having a plurality of openings at the bottom and a chamber chamber located at the lower portion of the drying chamber. That is, in this fluidized bed drying apparatus, fluidized gas (drying gas) is supplied from a wind box to a drying chamber through a perforated plate to dry the material to be dried while flowing (Patent Document 1 or 2). ).

Japanese Patent Laid-Open No. 04-13086 Japanese Patent Laid-Open No. 06-299176

  In the fluidized bed drying apparatus described in Patent Document 1 or 2, a mechanical stirring device is provided or the supply amount of fluidized gas at the inlet portion is adjusted so that the material to be dried does not cause flow failure at the inlet portion. In this case, there is a possibility that wear of the stirrer may become a problem in the case of a mechanical stirrer, while the fluidized gas is adjusted. In such a case, the effect may be insufficient.

In addition, fluidized bed drying apparatuses are widely used for drying powders, but selection of the particle size of an object to be dried is important in order to obtain good drying characteristics.
That is, when the particle size of the material to be dried is too large, the surface area of the particles is reduced, so that the amount of heat transfer is reduced and the drying rate is slowed down. On the other hand, when the particle size is reduced, there is a problem that the proportion of fine particles that are not sufficiently dried and carry over to the outside of the drying apparatus increases.
Therefore, it is necessary to reduce the average particle size reasonably and ensure the surface area necessary for drying, while narrowing the width of the so-called particle size distribution with a small proportion of fine particles.

  By the way, since the brown coal which is to be dried is soft, there is a problem that fine particles are easily generated in the process of crushing and the like, and the width of the particle size distribution is wide, and is a powder which is not originally suitable for fluidized bed drying.

In addition, since the lignite input portion has a large amount of water, it is essentially difficult to fluidize, particularly when there are many fine particles, it condenses and further fluidization becomes difficult.
Examples of means for adjusting the particle size and narrowing the width of the particle size distribution include crushing means and classification means, but for powders containing a large amount of water, classification using a sieve is difficult because it causes adhesion and clogging. It is.

  Therefore, without taking such measures, it is eagerly desired to take measures that can promote good fluidization and drying by achieving good mixing in the fluidized bed drying apparatus.

  In view of the above problems, the present invention provides a fluidized bed drying device and a fluidized bed drying facility capable of promoting good fluidization and promoting fluidization in a fluidized bed drying device when a material to be dried is supplied. The task is to do.

  The first invention of the present invention for solving the above-described problem is a fluidized bed drying apparatus for flowing and drying a material to be dried supplied to the drying chamber by supplying a fluidizing gas to the drying chamber. A crusher for crushing the material to be dried to a predetermined particle size, a first fluidization chamber for dividing the inside of the fluidized bed drying apparatus with a partition, supplying the crushed material to be dried, and starting fluidization and drying; , The fine particles flowed and dried in the first flow chamber overflow, the second flow chamber for further flow and drying, and the coarse particles discharged from the first flow chamber are transported to the crusher side A fluidized bed drying apparatus.

  A second invention is the fluidized bed drying according to the first invention, wherein the velocity of the fluidizing gas in the first fluidizing chamber is larger than the velocity of the fluidizing gas in the second fluidizing chamber. In the device.

  A third invention is the fluidized bed drying apparatus according to the first or second invention, wherein the second fluid chamber is divided into a plurality of fluid chambers.

  According to a fourth aspect of the present invention, there is provided the fluidized bed drying apparatus according to any one of the first to third aspects for drying an object to be dried having a high water content, and the superheated steam provided in the fluidized bed drying apparatus. A heat transfer member that removes moisture in the object to be dried and a generated steam line that discharges generated steam generated when the object to be dried is dried by the heat transfer member to the outside of the fluidized bed drying device; 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; A part of the generated steam from which dust is removed from the dust collector is branched, and a branch line that supplies the fluidized steam as fluidized steam into the fluidized bed drying device, and the material to be dried extracted from the fluidized bed drying device is cooled. Characterized by having a cooler In the drying equipment.

  According to the present invention, good mixing in a fluidized bed drying apparatus can be achieved, and fluidization can be promoted. Thereby, even when a material to be dried having a large particle size distribution is supplied, the material to be dried can be satisfactorily dried.

FIG. 1 is a schematic diagram showing an example of fluidized bed drying equipment to which a fluidized bed drying apparatus according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram showing an example of a combined coal gasification combined power generation system to which the fluidized bed drying facility shown in FIG. 1 is applied. FIG. 3 is a schematic view showing a fluidized bed drying apparatus according to the first embodiment.

  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 showing an example of fluidized bed drying equipment to which the fluidized bed drying apparatus according to the present embodiment is applied.

As shown in FIG. 1, a fluidized bed drying apparatus 100 according to this embodiment includes a fluidized bed drying apparatus 102 having a drying chamber that dries lignite coal 101 that is supplied from a supply hopper 120 and has a high moisture content. A heat transfer member (heating means) 103 provided in the fluidized bed drying apparatus 102 for supplying superheated steam (for example, steam at 150 ° C.) A to the inside of the tubular body to remove moisture in the brown coal 101, and the heat transfer A generated steam line L ₁ for discharging generated steam 104 generated when the lignite 101 is dried by the member 103 to the outside of the fluidized bed drying apparatus 102, and the generated steam line L ₁ , a dust collector 105 for removing dust, is interposed on the downstream side of the dust collecting apparatus 105 in generating steam line L _1, the heat recovery system 106 for recovering the steam generated 104 heat, the dust collector 05 branches a part of the steam generated 104 dust is removed from a branch line L ₂ to be supplied to the fluidized bed dryer 102 as a fluidizing steam 107, drying brown coal withdrawn from the fluidized bed dryer 102 And a cooler 110 that cools 108 to produce product charcoal 109.
Reference numeral 116 denotes a rectifying plate that rectifies the fluidized steam 107 that is a fluidized gas.

In the fluidized bed drying facility 100, the lignite 101 is introduced into the fluidized bed drying apparatus 102 by the supply hopper 120 via the supply line L ₀ and is fluidized by the fluidized steam 107 separately introduced into the fluidized bed drying apparatus 102. Thus, the fluidized bed 111 is formed.

  The heat transfer member 103 described above is disposed in the fluidized bed 111. In the heat transfer member 103, 150 ° C. superheated steam A is supplied, and the lignite 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 fluidized bed 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 the condensed latent heat dissipated at this time is effectively used for heating the drying of the lignite 101. . 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.

Generating steam 104 generated when the brown coal 101 is dried by the heat transfer member 103 is fluidized in the fluidized bed dryer 102, by generating from the freeboard section F steam line L ₁ formed in the upper space of the fluidized bed 111 It is discharged outside the layer drying apparatus 102. Since the generated steam 104 includes a material obtained by drying and pulverizing the lignite 101, the 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 lignite 108 in the product line L ₄ extracted from the fluidized bed drying apparatus 102 via the separation line L ₃ , cooled by the cooler 110, and used as product 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. Note that the generated steam 104 after being collected by the dust collector 105 may be applied to, for example, a heat exchanger, a steam turbine, or the like to effectively use the heat.

Part of the steam generated 104 after being dust collecting by a dust collector 105, is sent to the fluidized bed dryer 102 by the circulation fan 114 interposed in the branch line L _2, the fluidized bed of lignite 101 It is used as fluidized steam 107 that causes 111 to flow. As a fluidizing medium for fluidizing the fluidized bed 111, a part of the generated steam 104 is reused. However, the fluidizing medium is not limited to this. For example, nitrogen, carbon dioxide, or a low oxygen concentration containing these gases is used. Air may be used.

The fluidized bed drying apparatus 102 described above exemplifies a tube-shaped heat transfer member as the heat transfer member 103, but the present invention is not limited to this, for example, a plate-shaped heat transfer member May be used.
Moreover, although the structure which supplies superheated steam A to the heat-transfer member 103 and dries the lignite 101 indirectly was demonstrated, not only this but the lignite 101 is made into fluidized steam 107 which makes the fluidized bed 111 of the lignite 101 flow. It is good also as a structure dried directly by supplying the fluidizing gas for heating further, and drying.

  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.

  An example applied to an integrated coal gasification combined cycle (IGCC) system using product coal 109 dried by the fluidized bed drying apparatus 102 shown in FIG. 1 will be described. FIG. 2 is a schematic diagram showing an example of a combined coal gasification combined power generation system to which the fluidized bed drying facility 100A shown in FIG. 1 is applied.

  As shown in FIG. 2, the coal gasification combined power generation system 200 treats pulverized coal 201 a pulverized by a mill 210 with product coal (dry lignite) 109 as a fuel and converts it into gasification gas 202. Generated by a furnace 203, a gas turbine (GT) 204 that is operated using the gasified gas 202 as fuel, and a heat recovery steam generator (HRSG) 206 that introduces turbine exhaust gas 205 from the gas turbine 204 The steam turbine (ST) 208 operated by the steam 207 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 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 this coal gasification combined cycle power generation system 200, even when gasifying using lignite 101 having a high moisture content, since the lignite 101 is dried by the efficient fluidized bed drying apparatus 102, the gasification efficiency is high. The power generation can be improved 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.

  In addition, as a power generation system using the product charcoal 109 dried with the fluidized-bed drying equipment 100 concerning this Embodiment, it is not restricted to the coal gasification combined cycle power generation system 200 mentioned above. For example, although not explicitly shown in the figure, a brown coal cooking boiler that supplies product charcoal 109 dried in the fluidized bed drying facility 100 to a boiler furnace, drives a steam turbine with steam generated in the boiler furnace, and obtains output by a generator. May be a power generation system.

[First Embodiment]
Hereinafter, the fluidized-bed drying apparatus of the 1st form of this invention is demonstrated with reference to FIG.
As shown in FIG. 3, the fluidized bed drying apparatus 102 according to this embodiment supplies a fluidized gas to the drying chamber to flow and dry the material to be dried supplied to the drying chamber. 2, the crushing machine 130 for crushing the material to be dried (brown coal) 101 to a predetermined particle size (average particle size of about several mm) and the material to be dried by dividing the inside of the fluidized bed drying apparatus 102 by the partition wall 131. 101 is supplied to start fluidization / drying, and the first fluidization chamber 132A and the fine particles 134 fluidized / dried in the first fluidization chamber 132A overflow into the partition wall 131 to further fluidize / dry the fluid. A second flow chamber 132B and a conveying line L ₅ such as a belt conveyor for conveying the coarse particles 133 discharged from the first flow chamber 132A to the crusher 130 side are provided.

  Further, the speed (superficial speed) of the fluidized steam 107A in the first fluidizing chamber 132A is made larger than the speed (superficial speed) of the fluidized steam 107B in the second fluidizing chamber 132B.

In the present invention, the fluidized bed drying apparatus 102 is divided into a first fluidized chamber 132A and a second fluidized chamber 132B, and the first fluidized chamber 132A that supplies the brown coal 101 is caused to function as a fluidized bed classifier and a preliminary drying chamber. ing.
Then, by the coarse particles 133 dry in the first fluid chamber 132A screened and withdrawn by extraction means, not shown, via a transfer line L _5, sent to the crusher 130 side, mixed with wet lignite 101 After crushing, the fluidized bed drying apparatus 102 is supplied again.

  In this apparatus, first, the brown coal 101 is supplied to the crusher 130 and crushed. Here, it is preferable that the average particle size of the crushed lignite 101 at the outlet of the crusher 130 is larger than the required particle size of the dried lignite 108 after drying.

  When the required particle size of the dried brown lignite 108 after drying is set to 2 mm or less, for example, the crushing by the crusher 130 may be crushed to an average particle size of 4 mm.

Lignite 101 which are crushed to a predetermined particle size by a supply line L _0, and supplies the first hydraulic chamber 132A of the fluidized bed dryer 102.
The gas velocity in the first fluid chamber 132A is preferably higher than the velocity at which the layer of wet lignite 101 can be fluidized.
In this embodiment, the flow velocity is about 1 m / s, but is not limited to this.

The fine particles 134 that have been initially dried get over the partition 131 that separates the first fluid chamber 132A and the second fluid chamber 132B, and overflow to the second fluid chamber 132B side.
On the other hand, the coarse particles 133 settle to the bottom of the first fluid chamber 132A and are discharged out of the fluidized bed drying apparatus 102 by a dispensing means (not shown).

The discharged coarse particles 133 are sent to the crusher 130 side by the conveying line L ₅ and are pulverized again here.
The crushed coarse particles 133 are mixed with raw coal and then supplied again into the fluidized bed drying apparatus 102.

  The fluidizing gas in the first fluid chamber 132A and the second fluid chamber 132B uses fluidized steam in the present embodiment, but is not limited thereto, and may be another fluidizing gas.

According to the present invention, the first fluid chamber 132A functions as a fluidized bed classifier, and only the coarse particles 133 can be sorted and crushed, so that the width of the particle size distribution can be reduced.
As a result, excessive generation of fine particles can be prevented, and carryover is reduced.

  The particle size of the lignite 101 in the first fluidization chamber 132A is larger than the particle size of the lignite 101 in the second fluidization chamber 132B and is difficult to fluidize, but increases the speed of the fluidized steam 107A that is a fluidized gas. This ensures a good fluid state. In addition, since the particle size is large, even if the gas velocity of the fluidized steam 107A is increased, the carry-over as in the conventional case does not increase.

  Further, by mixing the partially dried coarse particles 133 with the wet lignite 101 again, the problems of adhesion / clogging at the inlet and flow failure in the layer are solved.

  As described above, according to the present invention, good mixing of the lignite 101 in the fluidized bed drying apparatus 102 can be achieved, and fluidization can be promoted. Thereby, even when brown coal 101 having a large particle size distribution is supplied, good drying can be performed.

  As described above, the fluidized bed drying apparatus and the fluidized bed drying equipment according to the present invention are suitable for implementing measures that can promote good fluidization and achieve good mixing in the fluidized bed drying apparatus. .

DESCRIPTION OF SYMBOLS 100 Fluidized bed drying equipment 101 Brown coal 102, 102A-102C Fluidized bed drying apparatus 103 Heat transfer member 104 Generated steam 105 Dust collector 106 Heat recovery system 107 Fluidized steam 108 Dry brown coal 109 Product coal 110 Cooler 111 Fluidized bed 112 Water treatment Part 113 Drainage 114 Circulation fan 115 Solid component 116 Current plate 130 Crusher 131 Bulkhead 132A First fluid chamber 132B Second fluid chamber 133 Coarse particles 134 Fine particles 200 Coal gasification combined power generation system 201 Coal 201a Pulverized coal 202 Gasification gas 203 Coal Gasifier 204 Gas Turbine (GT)
205 Turbine exhaust gas 206 Waste heat recovery boiler (HRSG)
207 Steam 208 Steam turbine (ST)
209 Generator (G)
210 Mil 211 Cyclone 212 Gas purification device 213 Combustor 214 Combustion gas 215 Exhaust gas 217 Chimney 218 Condenser 219 Air 220 Compressor 221 Air separation device (ASU)
A Superheated steam B Condensate F Free board

Claims (4)

In a fluidized bed drying apparatus for flowing and drying a material to be dried supplied to the drying chamber by supplying a fluidizing gas to the drying chamber,
A crusher for crushing the material to be dried to a predetermined particle size;
A first fluidization chamber that divides the fluidized bed drying apparatus with a partition wall, supplies a crushed material to be dried, and starts fluidization and drying;
A second fluidizing chamber in which fine particles fluidized and dried in the first fluidizing chamber overflow and further fluidize and dry;
A fluidized bed drying apparatus, comprising: a conveying line that conveys coarse particles discharged from the first fluidizing chamber to the crusher side. In claim 1,
A fluidized bed drying apparatus characterized in that the velocity of the fluidizing gas in the first fluidizing chamber is larger than the velocity of the fluidizing gas in the second fluidizing chamber. In claim 1 or 2,
A fluidized bed drying apparatus, wherein the second fluidized chamber is divided into a plurality of fluidized chambers. The fluidized bed drying apparatus according to any one of claims 1 to 3, which dries an object to be dried having a high water content;
A heat transfer member that is provided in the fluidized bed drying apparatus, supplies superheated steam to the inside of the tubular or plate shape, and removes moisture in the material to be dried;
A generated steam line for discharging generated steam generated when the material to be dried is dried by the heat transfer member to the outside of the fluidized bed drying device;
A dust collector interposed in the generated steam line to remove 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;
A branch line for branching a part of the generated steam from which dust is removed from the dust collector, and supplying the fluidized steam into the fluidized bed drying device;
A fluidized-bed drying facility comprising: a cooler that cools an object to be dried extracted from the fluidized-bed drying device.

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