JP2011214562A - Coal gasification combined power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coal gasification combined power generation system excelling in heat efficiency by effectively utilizing produced steam produced when drying moisture of high water content charcoal such as lignite, and requiring a small supply quantity of water supplied from the outside.SOLUTION: The coal gasification combined power generation system includes a fluidized bed drying system 102 drying watery dried object coal; a heat recovery device 106 recovering heat using the produced steam produced in a fluidized bed drying device; a coal gasifying furnace 203 treating pulverized fine powder coal 201a so as to be changed into gasified gas 202; a gas turbine 204 operated with the gasified gas 202 as fuel; a steam turbine 208 operated with steam 207 produced in an exhaust heat recovery boiler 206 introducing turbine exhaust gas 205 from the gas turbine 204; and a generator 209 connected to the gas turbine 204 and/or the steam turbine 208. High temperature steam (superheated steam A) produced in the heat recovery system 106 is used as a heat source of the fluidized bed drying device 102.

Description

  The present invention relates to a coal gasification combined power generation system.

Coal, petroleum, and other hydrocarbon fuels are relatively easy to handle, and many plants that use this to generate electricity have been operating. In particular, coal has attracted attention as one of the promising fuels because it has a huge reserve and can be supplied stably in the future. However, since the carbon (C) content contained in the fuel is larger than that of other hydrocarbon fuels, there is a problem that the amount of CO ₂ emission per unit heat amount is large. In particular, in recent years, from the viewpoint of global environmental conservation, reducing CO ₂ emissions has become an important issue that should be achieved immediately. Here, if the efficiency of the power plant is improved, the amount of fuel necessary to generate the same electric power can be reduced, so that the amount of CO ₂ emission can be reduced. Therefore, in the conventional coal-fired power plants, it measures for suppressing CO ₂ emissions by improving the efficiency of the plant had been taken.

As a technique for improving the plant efficiency, a technique called Integrated Coal Gasification Combined Cycle (IGCC) is known. In this technique, coal is not burned as it is, but is once gasified and supplied as a fuel for power generation. In coal gasification combined cycle power generation, the efficiency of a coal-fired power plant, which was about 40% in the past, can be improved to about 46% by combining with a gas turbine and a steam turbine. By improving the plant efficiency, CO ₂ emissions can be reduced by about 13% compared to conventional coal fired boilers (Patent Documents 1 and 2, Non-Patent Document 1).

JP-A-10-251669 JP 2003-106514 A

Mitsubishi Heavy Industries Technical Report Vol. 36No. 1 (1999-1)

  IGCC that uses a dry coal supply system can be applied to relatively high-moisture coal, but low-grade coal such as lignite and sub-bituminous coal brings in a lot of moisture, and this moisture reduces power generation efficiency. There is.

  In addition, gas purification equipment for gasification gas requires water for cooling and cleaning, but there is a problem that it is difficult to supply water under an environment such as a desert.

  Therefore, the emergence of a coal gasification combined power generation system with good thermal efficiency and low supply of water supplied from the outside by effectively using the steam generated when drying the moisture of high moisture coal such as lignite is desired. ing.

  In view of the above problems, the present invention is a coal gasification composite that has a good thermal efficiency by effectively using generated steam generated when drying moisture of high-moisture coal such as lignite and has a small amount of water supplied from the outside. It is an object to provide a power generation system.

  The first invention of the present invention for solving the above-described problem is to perform heat recovery using a fluidized bed drying device for drying a coal to be dried having a high water content and generated steam generated in the fluidized bed drying device. A heat recovery device, a mill that finely pulverizes the product coal after drying, a coal gasification furnace that processes pulverized coal pulverized by the mill and converts it to gasification gas, and is operated using the gasification gas as fuel A gas turbine, a steam turbine operated by steam generated by an exhaust heat recovery boiler for introducing turbine exhaust gas from the gas turbine, and a generator connected to the gas turbine and / or the steam turbine. The high temperature steam generated in the heat recovery device is used as a heat source of the fluidized bed drying device.

  According to a second aspect of the present invention, there is provided the coal gasification combined power generation system according to the first aspect, wherein the heat recovery device is either a superheater or a booster using the extracted steam from the steam turbine.

  According to a third invention, in the second invention, a gas purifier for purifying the gasification gas from the coal gasification furnace is provided, which is obtained by either a superheater or a booster using extracted steam from a steam turbine. The coal gasification combined power generation system is characterized in that the superheated steam is used as a condensed water using a fluidized bed drying device, and then the condensed water is used in the gas purification device.

  According to a fourth invention, in the second invention, a gas purification device including a dust removal device for purifying the gasification gas from the coal gasification furnace and a CO shift reaction device is provided, and the extracted steam from the steam turbine is used. The superheated steam obtained by either the superheater or the booster is heat-exchanged by the superheater using the extracted steam from the steam turbine, and then used in the CO shift reactor of the fluidized bed drying apparatus. In the coal gasification combined power generation system.

  According to the present invention, there is provided a coal gasification combined power generation facility having a good thermal efficiency and a small amount of water supplied from the outside by effectively utilizing generated steam generated when drying moisture of high moisture coal such as lignite. Can be provided.

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 illustrating an example of a combined coal gasification combined power generation system according to the first embodiment to which the fluidized bed drying facility illustrated in FIG. 1 is applied. FIG. 3 is a schematic diagram illustrating an example of a combined coal gasification combined power generation system according to a second embodiment to which the fluidized bed drying facility illustrated in FIG. 1 is applied. FIG. 4 is a schematic diagram illustrating an example of a combined coal gasification combined power generation system according to a third embodiment to which the fluidized bed drying facility illustrated in FIG. 1 is applied.

  Hereinafter, the present invention will be described 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 assumed by those skilled in the art or those that are substantially the same.

[First Embodiment]
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 dispersion plate for dispersing and blowing fluidized vapor 107, which is a fluidized gas, in the form of bubbles.

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 100 shown in FIG. 1 is applied.

  As shown in FIG. 2, the coal gasification combined power generation system 200 </ b> A is a coal gasification in which product coal (dry lignite) 109 as a fuel is processed into pulverized coal 201 a pulverized by a mill 210 and converted 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.

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

  According to the combined coal gasification combined power generation system 200A, even when gasifying using lignite 101 having high moisture, the lignite 101 is dried by the efficient fluidized bed drying apparatus 102. The efficiency can be prevented from being reduced and power can be generated stably over a long period of time.

  In the coal gasification combined power generation system 200A of the present embodiment, as the heat recovery system 106, the generated steam 104 after being collected by the dust collector 105 is indirectly heat-exchanged by the extracted steam 208a extracted from the steam turbine 208. A heat exchanger 106A is provided.

  Thus, the generated steam 104 is superheated by the heat exchanger 106A to be superheated steam A that is a 150 ° C. superheated medium, and is again supplied to the heat transfer member 103 of the fluidized bed drying apparatus 102 as superheated steam A. It is possible to use the superheated medium effectively.

[Second Embodiment]
Next, the combined coal gasification combined power generation system 200B of the second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same component as the coal gasification combined cycle system of 1st Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 3, the combined gasification combined cycle system 200B of the second embodiment is provided with a booster 106B instead of the heat exchanger 106A of the combined coal gasification combined cycle system 200A of the first embodiment. Thus, the generated steam 104 is superheated to be superheated steam A that is a 150 ° C. superheated medium, and is again supplied to the heat transfer member 103 of the fluidized bed drying apparatus 102 as superheated steam A. Can be used.

  Further, as shown in FIG. 3, in the gas purification device 212, water is required by a scrubber or the like for gas cooling. Therefore, the condensed water B used for drying the lignite 101 by the fluidized bed drying device 102 is used as the scrubber spray water. For example, the water may be used effectively.

[Third Embodiment]
Next, the coal gasification combined cycle power generation system 200C of the third embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same component as the coal gasification combined cycle system of 1st and 2nd embodiment, and the description is abbreviate | omitted.
As shown in FIG. 4, the combined gasification combined cycle system 200C of the third embodiment is provided with a booster 106B instead of the heat exchanger 106A of the combined coal gasification combined cycle system 200A of the first embodiment. Thus, the generated steam 104 is superheated to be superheated steam A that is a 150 ° C. superheated medium, and is again supplied to the heat transfer member 103 of the fluidized bed drying apparatus 102 as superheated steam A. Further, the superheated steam A can be supplied to the gas purifier 212 for effective use.

Here, the gasification gas 202 from the coal gasification furnace 203 is refined before being supplied to the gas turbine 204. At that time, the gas purification device 212 uses a scrubber or the like to collect dust in the gas. To be removed.
Since the superheated steam A used for drying this water in the fluidized bed drying apparatus 102 is discharged as the condensed water B, the water can be effectively used by using the condensed water B as the scrubber water.

Here, an example is shown about the structure of the gas purification apparatus 212 of the coal gasification combined cycle system 200C of 3rd Embodiment.
The gasified gas 202, which is the product gas, is first dedusted by a dedusting device 212a such as a scrubber, then a CO shift reaction is caused by the CO shift reaction device 212b, and then the CO _{2 is} recovered by the H ₂ S / CO ₂ recovery device 212c. ₂ is recovered, and H ₂ S in the gas is removed.
Thus, the gasification gas 202, the CO ₂ before separating in H ₂ S / CO ₂ recovery unit 212c, a so-called CO shift reaction unit 212b for converting the CO contained in the gasification gas 202 to CO ₂ At this time, high-temperature steam is used.
This CO shift reaction is to obtain useful components CO ₂ and H ₂ by the reaction of the following formula (1).
CO + H ₂ O → CO ₂ + H ₂ (1)
Note that CO is converted to CO ₂ by various CO shift catalysts as a catalyst for promoting the CO shift reaction.

In this embodiment, the superheater 130 which introduces the superheated steam A into the superheater 130 and indirectly exchanges heat with the extracted steam 208a extracted from the steam turbine 208 is provided.
The CO shift reaction can be promoted by supplying the high temperature steam 131 of about 300 ° C. heated by the superheater 130 to the CO shift reaction device 212b.

  Further, the steam may be supplied into the coal gasification furnace 203 as a gasifying agent.

As described above, in the combined coal gasification combined power generation systems 200A to 200C, the efficiency of the coal-fired power plant that has been about 40% 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.

Moreover, according to this coal gasification combined cycle power generation system 200A-C, even when gasifying using lignite having high moisture, since an efficient drying device is used, the reduction in gasification efficiency due to moisture is prevented. And can generate electricity stably over a long period of time.
Moreover, the generated steam generated during the drying of lignite can be used effectively, and a system with good energy efficiency can be constructed.

  The present invention is not limited to the embodiment described above, and can be appropriately modified as necessary. Further, each component in the above embodiment includes those that can be easily assumed by those skilled in the art and those that are substantially the same.

  As described above, according to the fluidized bed drying apparatus of the present invention, it is possible to effectively use the generated water vapor generated during the drying of lignite, and to provide a system with good energy efficiency.

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 106A Heat exchanger 106B Booster 107 Fluidized steam 108 Dry brown coal 109 Product coal 110 Cooling Unit 111 Fluidized bed 112 Water treatment unit 113 Drainage 114 Circulating fan 115 Solid component 116 Current plate 130 Superheater 131 High-temperature steam 200A-C Coal gasification combined power generation system 201 Coal 201a Pulverized coal 202 Gasification gas 203 Coal gasification furnace 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)

A fluidized-bed drying device for drying dry matter coal with a high water content;
A heat recovery device for recovering heat using generated steam generated in the fluidized bed drying device;
A mill for pulverizing the product charcoal after drying;
A coal gasification furnace that processes pulverized coal crushed by a mill and converts it to gasification gas;
A gas turbine operated using the gasified gas as fuel;
A steam turbine operated by steam generated by an exhaust heat recovery boiler that introduces turbine exhaust gas from the gas turbine, and a generator connected to the gas turbine and / or the steam turbine,
A coal gasification combined power generation system using high-temperature steam generated in the heat recovery device as a heat source of a fluidized bed drying device. In claim 1,
The coal gasification combined power generation system characterized in that the heat recovery device is either a superheater or a booster using extracted steam from a steam turbine. In claim 2,
A gas purification device for purifying gasification gas from the coal gasification furnace is provided,
The superheated steam obtained by either the superheater using the steam extracted from the steam turbine or the booster is converted into condensed water using a fluidized bed drying device, and then the condensed water is used in the gas purification device. Coal gasification combined power generation system characterized by that. In claim 2,
A gas purification device including a dust removal device for purifying gasification gas from the coal gasification furnace and a CO shift reaction device is provided,
The superheated steam obtained by either the superheater using the steam extracted from the steam turbine or the booster is heat-exchanged by the superheater using the steam extracted from the steam turbine, and then the CO shift reaction of the fluidized bed drying device. A coal gasification combined power generation system characterized by being used in an apparatus.

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