JP2020079674A - Woody biomass power generation system and power generation method - Google Patents

Abstract

To efficiently use combustion heat of woody biomass in a woody biomass power generation system.SOLUTION: A woody biomass power generation system 1 includes: a dryer 11 drying fuel; an air preheater 32 preheating combustion air; a boiler 31 burning the fuel dried by the dryer 11 by using the combustion air; and at least one power generation steam turbine 101, 102 driven by steam heated by the boiler 31. The dryer 11 is configured to dry the fuel by using heat of first extracted steam extracted from the power generation steam turbines 101, 102, and the air preheater 32 is configured to preheat the combustion air by using heat of second extracted steam extracted from the power generation steam turbines 101, 102 and having a temperature higher than that of the first extracted steam.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a woody biomass power generation system and a power generation method for generating power using woody biomass such as woody chips and wood pellets as a fuel.

  Conventionally, from the viewpoint of reducing greenhouse gas emissions, etc., a power generation system that uses renewable energy (solar, wind, geothermal, biomass, etc.) that is considered to be permanently usable as an energy source instead of fossil fuels. Is being introduced. In particular, since wood biomass has the advantage that it does not change due to weather conditions such as sunlight and wind power, wood biomass power generation systems that generate power using wood biomass as fuel have recently attracted attention. ..

  In a woody biomass power generation system, it is desirable to reduce the amount of water contained in woody biomass used as a fuel by pretreatment or the like in order to increase combustion efficiency in a boiler. Therefore, for example, a method of drying a biomass fuel used as an auxiliary fuel for coal to be burned in a furnace of a boiler, in which combustion exhaust gas generated in the furnace is extracted, and this is a biomass fuel before being fed into the furnace. There is known a method in which the flue gas is used as a heat source for drying the flue gas, the flue gas after use is cooled to collect water, and then mixed with combustion air and supplied into the furnace (see Patent Document 1).

JP, 2005-291526, A

  By the way, in the prior art as described in Patent Document 1, the combustion exhaust gas at a relatively high temperature (for example, 350 to 400° C.) is used for drying the fuel (woody biomass), and the combustion exhaust gas after the use is used. After cooling and collecting water, it is mixed with combustion air and supplied to the furnace, so the combustion exhaust gas (combustion heat) used for fuel drying and combustion is not directly used for power generation and does not contribute to power generation. There is a problem that the proportion of heat energy increases. In particular, when woody biomass is used as a main fuel of a power generation system or when a relatively large power generation output is required, such a problem becomes more remarkable.

  The present invention has been devised in view of such problems of the conventional technology, and provides a woody biomass power generation system and a power generation method capable of efficiently using the combustion heat of woody biomass. The main purpose.

  In the first aspect of the present invention, there is provided a woody biomass power generation system (1) for generating power using woody biomass as a fuel, which is a dryer (11) for drying fuel and an air preheater for preheating combustion air. (32), a boiler (31) for combusting the fuel dried by the dryer with the combustion air, and at least one steam turbine for power generation (101) driven by steam heated by the boiler. , 102), and the dryer dries the fuel by the heat of the first extracted steam taken out from the steam turbine for power generation, and the air preheater is taken out from the steam turbine for power generation. And, the combustion air is preheated by the heat of the second extraction steam having a temperature higher than that of the first extraction steam.

  According to this, a plurality of extracted steams with different temperatures extracted from a steam turbine for power generation are used respectively for drying wood biomass and preheating combustion air for burning wood biomass, so that the combustion heat of wood biomass in the system is Can be used efficiently.

  In the second aspect of the present invention, the blower (12) for supplying drying air and the drying air introduced into the dryer are heated by heat exchange between the first extraction steam and the drying air. And a heat exchanger (13) for heating.

  According to this, with a simple configuration, the extracted steam extracted from the steam turbine for power generation can be used for drying the woody biomass.

  A third aspect of the present invention is characterized in that the temperature of the drying air introduced into the dryer is in the range of 120°C to 150°C.

  According to this, by setting the drying air in an appropriate temperature range (120° C. to 150° C.), the extracted steam can be efficiently used for drying the woody biomass.

  In a fourth aspect of the present invention, the dryer includes a storage container (22) for storing the fuel and introducing the drying air, and the drying air containing the moisture of the fuel from the storage container. And a vent (23) for discharging.

  According to this, it becomes possible to efficiently dry the woody biomass with a simple configuration using the drying air supplied from the blower.

  A fifth aspect of the present invention is characterized in that the temperature of the combustion air introduced into the boiler from the air preheater is in the range of 200°C to 250°C.

  According to this, by setting the combustion air in an appropriate temperature range (200° C. to 250° C.), the extracted steam can be efficiently used for preheating the combustion air.

  In the sixth aspect of the present invention, the steam turbine for power generation is driven by a high pressure steam turbine (101) driven by the higher pressure steam and a lower pressure steam supplied through the high pressure steam turbine. A low pressure steam turbine (102) according to the present invention, wherein the first and second extracted steam are extracted from the low pressure steam turbine.

  According to this, while generating power using the high-pressure steam turbine and the low-pressure steam turbine, in the plurality of extracted steam of different temperatures extracted from the low-pressure steam turbine, the lower temperature steam is used to dry the woody biomass, Moreover, by using the higher temperature steam for preheating the combustion air, it is possible to more efficiently use the combustion heat of the woody biomass.

  In the seventh aspect of the present invention, a condenser (104) attached to the steam turbine for power generation is further provided, and the first extracted steam used for drying the fuel in the dryer is the condenser. It is characterized by being circulated in a water vessel.

  According to this, with a simple structure, it becomes possible to effectively utilize the extracted steam used for drying the woody biomass.

  In the eighth aspect of the present invention, the fuel contains 40 to 50% by weight of water before being dried by the dryer, and 20% by weight or less of water after being dried by the dryer. ..

  According to this, by setting the water content ratio before and after the drying of the woody biomass in an appropriate range, it becomes possible to efficiently dry and burn the woody biomass.

  According to a ninth aspect of the present invention, there is provided a woody biomass power generation method for generating power using woody biomass as a fuel, which comprises a drying step of drying the fuel, an air preheating step of preheating combustion air, and the drying step. A combustion step of combusting the dried fuel with the combustion air, and a power generation step of driving at least one power generation steam turbine (101, 102) with steam heated by combustion heat in the combustion step, In the drying step, the fuel is dried by the heat of the first extraction steam extracted from the power generation steam turbine, and in the air preheating step, the fuel is extracted from the power generation steam turbine, and It is characterized in that the combustion air is preheated by the heat of the second extracted steam having a temperature higher than that of the first extracted steam.

  According to this, by using a plurality of extracted steam extracted from a steam turbine for power generation at different temperatures for drying wood biomass and preheating combustion air for burning wood biomass, respectively, the combustion heat of wood biomass can be efficiently used. It can be used for.

  As described above, according to the present invention, it is possible to efficiently use the combustion heat of woody biomass.

Overall configuration diagram of a woody biomass fuel power generation system according to an embodiment

  Hereinafter, embodiments of a woody biomass power generation system and a power generation method thereof according to the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram showing an outline of a woody biomass fuel power generation system 1 according to an embodiment.

  A woody biomass fuel power generation system 1 (hereinafter referred to as a power generation system 1) uses woody biomass (that is, wood-derived organic resources (excluding fossil fuel) such as woody chips and wood pellets) as a fuel, and burns this. To generate electricity. The power generation system 1 includes a reception facility 2 that receives fuel, a combustion facility 3 that burns fuel, and a power generation facility 4 that uses combustion heat generated in the combustion facility 3 to generate power.

  The power generation system 1 is not limited to the equipment 2-4 described above, but may include other known equipment (for example, dust collection equipment, water treatment equipment). Further, although the power generation system 1 uses woody biomass as the main fuel, it is also possible to use other known fuels (including fossil fuels) as a secondary fuel mixed with the woody biomass as necessary.

  Next, details of the receiving facility 2 in the power generation system 1 will be described. The receiving facility 2 includes a fuel storage 9 and a first conveyor 10, and a dryer 11 and a blower 12 for drying the fuel.

  The fuel storage 9 stores fuel that has been received from a vehicle or the like (not shown) for transporting fuel. Further, the first conveyor 10 conveys the fuel discharged from the fuel storage 26 to the dryer 11 (a receiving hopper 21 described later).

  The dryer 11 includes a receiving hopper 21, a storage container 22, and a vent 23. Further, the dryer 11 is provided with a heat exchanger 13 arranged between the storage container 22 and the drying blower 12.

  The receiving hopper 21 receives the fuel conveyed by the first conveyor 10. This fuel is one of wood chips, wood pellets and wood biomass, or a mixture of a plurality of these. The water content of the wood pellets (before drying) is usually about 10 to 15% by weight. The water content of the wood chips (before drying) is usually about 40 to 50% by weight.

  In general, the price of woody biomass tends to be lower as the water content increases. Therefore, in the power generation system 1, by appropriately setting (controlling) the moisture content rate of the woody biomass (before drying) received by the receiving facility 2 in a relatively high range (for example, 40 to 50% by weight), the fuel is acquired. The cost can be reduced.

  The storage container 22 stores the fuel received by the receiving hopper 21. The storage container 22 performs a process of drying the stored fuel by circulating the drying air described later inside. The drying process in the storage container 22 is performed in a batch system, and the dried fuel is intermittently discharged from the bottom portion thereof. However, the drying process of the container 22 can also be performed in a continuous manner. Further, the container 22 may further include a device for promoting the drying of the fuel (for example, a stirring device for stirring the stored fuel).

  The water content of the fuel after the drying process in the container 22 is preferably, for example, 20% by weight or less. In the power generation system 1, by setting (controlling) the moisture content after drying of the woody biomass in the receiving equipment 2 to an appropriate range (here, 20% by weight or less), the drying and combustion equipment 3 of the woody biomass can be performed. It becomes possible to carry out combustion efficiently.

  The vent 23 discharges the drying air in the container 22 containing the moisture removed from the fuel to the outside.

  The blower 12 for drying supplies the drying air (here, the atmosphere) to the container 22 containing the fuel. The heat exchanger 13 heats the drying air (normal temperature) sent from the drying blower 12 to a predetermined temperature by heat exchange with steam which will be described in detail later. The drying blower 12 and the heat exchanger 13 may be provided integrally with the storage container 22.

  The temperature of the drying air (after heating) supplied to the container 22 is preferably set (controlled) in the range of 120 to 150°C. By setting the temperature of the drying air to 120° C. or higher, poor drying of the fuel can be suppressed, and by setting the temperature of the drying air to 150° C. or lower, the thermal decomposition of the woody biomass is suppressed. be able to.

  The receiving facility 2 also includes a second conveyor 25 for supplying dry fuel to the boiler 31.

  The second conveyor 25 conveys the fuel (after drying) discharged from the dryer 11 to the combustion equipment 3 (fuel feeder 51 described later).

  In addition, in the power generation system 1, a plurality of receiving equipments 2 can be provided for one combustion equipment 3. In that case, for example, different fuels (for example, wood chips having a relatively high water content and wood pellets having a relatively low water content) are received by a plurality of receiving equipments 2, and the receiving equipments 2 receive the fuels according to the operating conditions of the combustion equipments 3. The amount of fuel supplied to the combustion equipment 3 (supply ratio between the receiving equipments 2) can be adjusted. As a result, it becomes easy to adjust the water content and the heat generation amount of the fuel supplied to the combustion equipment 3, and the degree of freedom of the drying process by the dryer 11 also increases.

  Next, details of the combustion equipment 3 in the power generation system 1 will be described. The combustion facility 3 includes a boiler 31 and an air preheater 32.

  The boiler 31 includes a combustion chamber 41, a boiler body 42, a cyclone 43, a convection heat transfer chamber 44, a seal pot 45, and an FBHE (fluidized bed heat exchanger) 46.

  The combustion chamber 41 burns the fuel supplied from the receiving facility 2 with the combustion air supplied from the air preheater 32. A fuel feeder 51 is attached to the combustion chamber 41. The fuel feeder 51 supplies the fuel carried by the second conveyor 25 from the dryer 11 to the combustion chamber 41. Exhaust gas (combustion gas) generated in the combustion chamber 41 is sent to the boiler main body 42 that is connected to the upper portion of the combustion chamber 41.

  Further, the combustion chamber 41 is provided with a fuel tank 52 that stores auxiliary fuel (here, light oil). The auxiliary fuel in the fuel tank 52 is supplied to the burner 54 by the pump 53 through the auxiliary fuel supply line L1. When the boiler 31 is started, the burner 54 burns the auxiliary fuel with the combustion air supplied from the air preheater 32, thereby igniting the fuel (woody biomass). The burner 54 can be used not only when the boiler 31 is started, but also appropriately depending on the combustion state of the fuel in the combustion chamber 41.

  The boiler body 42 includes an evaporation pipe 61 and a tertiary superheater 62. The evaporation pipe 61 is installed in a circulation line L2 that circulates steam with the steam drum 63 attached to the boiler 31. The tertiary superheater 62 is installed in the main steam line L3 that supplies steam from the steam drum 63 to the power generation equipment 4 (high-pressure steam turbine 101 described later). The steam flowing through the evaporation pipe 61 and the tertiary superheater 62 is heated by heat exchange with the exhaust gas flowing through the boiler body 42. The exhaust gas that has passed through the boiler body 42 is sent to the cyclone 43 that is connected to the downstream side of the boiler body 42.

  The cyclone 43 removes dust from the exhaust gas (separates fly ash contained in the exhaust gas). Further, the cyclone 43 includes a primary superheater 65 installed in the main steam line L3. The steam flowing through the primary superheater 65 is heated by heat exchange with the exhaust gas flowing through the cyclone 43. The exhaust gas dedusted by the cyclone 43 is sent to the convection heat transfer chamber 44 connected to the outlet pipe at the upper part thereof. On the other hand, the flow containing the fly ash separated from the exhaust gas by the cyclone 43 is introduced into the seal pot 45.

  The convection heat transfer chamber 44 includes a secondary superheater 71, a reheater 72, and a economizer 73 arranged on the downstream side thereof. The secondary superheater 71 is installed in the main steam line L3. Further, the reheater 72 is installed in the exhaust steam line L4 for supplying the exhaust steam from the high-pressure steam turbine 101, which will be described later, to the low-pressure steam turbine 102. The steam flowing through the secondary superheater 71, the reheater 72, and the economizer 73 is heated by heat exchange with the exhaust gas flowing through the convection heat transfer chamber 44. The exhaust gas that has passed through the convection heat transfer chamber 44 is sent to the air preheater 32 via the discharge passage 75.

  In the seal pot 45, a flow mainly made of fly ash is sent to the FBHE 46 via the fly ash transport pipe 81, while a flow mainly made of gas is circulated to the combustion chamber 41 via the gas circulation pipe 82.

  The FBHE 46 includes a fourth superheater 85 installed in the main steam line L3. The steam flowing through the fourth superheater 85 is heated by heat exchange with the flow from the fly ash transport pipe 81 (mainly composed of fly ash).

  With such a configuration, the steam supplied from the steam drum 63 to the power generation facility 4 includes the primary superheater 65, the secondary superheater 71, the tertiary superheater 62, and the fourth superheater installed in the main steam line L3. It is heated by passing through the vessel 85 in sequence. As a result, the combustion heat generated in the boiler 31 can be used in the power generation facility 4.

  The air preheater 32 includes a preheater body 90 provided with a first heat transfer tube 91 and a second heat transfer tube 92. The first heat transfer tube 91 and the second heat transfer tube 92 heat the combustion air used in the combustion equipment 3 by heat exchange with the exhaust gas flowing through the preheater body 90. The first combustion blower 93 supplies combustion air to the first heat transfer pipe 91 via the first combustion air line L5. Further, the second combustion blower 94 supplies the combustion air to the second heat transfer pipe 92 via the second combustion air line L6.

  Further, the air preheater 32 is additionally provided with a first auxiliary preheater 95 arranged between the first heat transfer pipe 91 and the first combustion blower 93. The first auxiliary preheater 95 heats the combustion air sent from the first combustion blower 93 to a predetermined temperature by heat exchange with steam described later in detail. The combustion air heated by the first auxiliary preheater 95 is further heated by the first heat transfer tube 91 and then supplied to the combustion chamber 41 via the first combustion air line L5.

  Similarly, the air preheater 32 is provided with a second auxiliary preheater 96 arranged between the second heat transfer pipe 92 and the second combustion blower 94. The second auxiliary preheater 96 heats the combustion air sent from the second combustion blower 94 to a predetermined temperature by heat exchange with steam described later in detail. The combustion air heated by the second auxiliary preheater 96 is further heated by the second heat transfer tube 92 and then supplied to the burner 54 via the second combustion air line L6. The supply of the combustion air by the second combustion blower 94 can be stopped when the burner 54 is not used.

  The temperature of the combustion air heated by the air preheater 32 (that is, supplied to the combustion chamber 41) is preferably set (controlled) to 200 to 250°C. As a result, the efficiency of the boiler 31 can be increased by utilizing the relatively low-temperature steam extracted from the low-pressure steam turbine 102 described below.

  Although not shown, incineration ash and fly ash discharged from the boiler 31 (the combustion chamber 41, the convection heat transfer chamber 44, the FBHE 46, etc.) and the air preheater 32 are sent to the ash treatment facility. Further, the exhaust gas discharged from the air preheater 32 is emitted from the chimney through the exhaust gas treatment device (nitrogen oxide removal device), the dust collector, and the like.

  Next, details of the power generation equipment 4 in the power generation system 1 will be described.

  The power generation facility 4 includes a high-pressure steam turbine 101, a low-pressure steam turbine 102, a generator 103, a condenser 104, a deaerator 105, and a feed water heater group (first to fifth feed water heaters 106a to 106e).

  The high-pressure steam turbine 101 is driven by the steam supplied from the boiler 31 via the main steam line L3. The steam extracted from the high-pressure steam turbine 101 via the extraction line L7 is sequentially introduced into the fourth and fifth feed water heaters 106d and 106e, and then sent to the deaerator 105.

  On the other hand, a part of the exhaust steam of the high-pressure steam turbine 101 is supplied to the low-pressure steam turbine 102 via the exhaust steam line L4 provided with the reheater 72 described above. Further, a part of the exhaust steam of the high-pressure steam turbine 101 is introduced into the fourth feed water heater 106d via a branch line L8 branched from the exhaust steam line L4, and then sent to the deaerator 105. Note that the position and number of extraction air in the high-pressure steam turbine 101 can be changed without being limited to the above example.

  The low-pressure steam turbine 102 is driven by the steam supplied from the high-pressure steam turbine 101 via the exhaust steam line L4. The low-pressure steam turbine 102 is a multi-stage extraction steam turbine, and steam of different pressures is extracted via the first to fourth extraction lines L9a to L9d.

  The high-pressure stage (first stage) steam having the highest pressure extracted from the low-pressure steam turbine 102 is sent to the deaerator 105 via the first extraction line L9a. In addition, the steam of the first medium pressure stage (second stage) having the next highest pressure is supplied to the third feed water heater 106c, the second feed water heater 106b, and the first feed water heater via the second extraction line L9b. 106a are sequentially introduced. Further, the second medium-pressure stage (third stage) steam having the next highest pressure is sequentially introduced into the second feed water heater 106b and the first feed water heater 106a via the third extraction line L9c. The vapor in the low pressure stage (fourth stage) having the lowest pressure is introduced into the first feed water heater 106a via the fourth extraction line L9d. The steam introduced into the first feed water heater 106a is sent to the condenser 104 via the condensate line L10. The position and the number of extraction air in the low-pressure steam turbine 102 can be changed without being limited to the above example.

  The power generation facility 4 is provided with a dry air steam line L11 that branches from the fourth extraction line L9d and a heated air steam line L12 that branches from the second extraction line L9b.

  The above-mentioned heat exchanger 13 is provided in the dry air steam line L11, and the downstream end of the dry air steam line L11 is connected to the condensate line L10. Thus, the steam (first extraction steam) flowing through the dry air steam line L11 is introduced into the heat exchanger 13 by the pump 111 and then sent to the condenser 104. The temperature of the steam flowing through the dry air steam line L11 is set so that the temperature of the dry air supplied from the heat exchanger 13 to the housing container 22 can be set in the range of 120°C to 150°C as described above. It is preferable to set.

  The above-described first auxiliary preheater 95 and second auxiliary preheater 96 are provided in the heated air steam line L12, and the downstream end of the heated air steam line L12 is connected to the deaerator 105. The steam (second extraction steam) flowing through the steam line L12 for heated air is introduced into the first auxiliary preheater 95 and the second auxiliary preheater 96 by the pump 112 and then sent to the condenser 104. The temperature of the steam flowing in the heating air steam line L12 is set so that the temperature of the combustion air supplied from the air preheater 32 to the combustion chamber 41 can be set in the range of 200 to 250° C. as described above. Preferably. The second auxiliary preheater 96 is provided in the bypass line L12a provided in the middle part of the heated air vapor line L12.

  The condenser 104 is connected to the deaerator 105 via the first reheating line L13. The flow (saturated water) of the first reheating line L13 is sequentially sent to the first to third feed water heaters 106a to 106c by the pump 115, and the low-pressure steam turbine 102 in the first to third feed water heaters 106a to 106c. After being sequentially heated by heat exchange with the steam from, the gas is supplied to the deaerator 105.

  The deaerator 105 is connected to the steam drum 63 via the second reheating line L14. The flow of the second reheating line L14 is sequentially sent to the fourth and fifth feed water heaters 106d and 106e by the pump 116, and the steam from the high-pressure steam turbine 101 is supplied to the fourth and fifth feed water heaters 106d and 106e. After being sequentially heated by the heat exchange of 1, the steam drum 63 is supplied.

  The generator 103 is connected to the drive shafts of the high pressure steam turbine 101 and the low pressure steam turbine 102 (power generation steam turbine), and is driven by them. The output of the steam turbine for power generation in the power generation system 1 is preferably set to be relatively high, and may be set to, for example, about 50 MW to 100 MW.

  As described above, in the power generation system 1, the plurality of extracted steams having different temperatures extracted from the low-pressure steam turbine 102 are used for drying the woody biomass and preheating combustion air for burning the woody biomass. It becomes possible to efficiently use the combustion heat of woody biomass. As a result, in the power generation system 1, the case where the exhaust gas from the boiler is used for drying the woody biomass and the preheating of the combustion air, and the case where the steam in the steam drum is used as it is (that is, without passing through the steam turbine for power generation) In comparison, it is possible to make the boiler compact and reduce the operating cost of the system.

  In addition, in the power generation system 1, while using a plurality of steam turbines for power generation to generate electric power, in the plurality of extracted steams of different temperatures extracted from the lower pressure steam turbine, the lower temperature steam is dried into the wood biomass. It is possible to use the combustion heat of the woody biomass more efficiently by utilizing the steam of higher temperature to preheat the combustion air.

  The present invention has been described above based on the specific embodiments, but these embodiments are merely examples, and the present invention is not limited to these embodiments. Each of the constituent elements of the woody biomass power generation system and the power generation method according to the present invention shown in the above-described embodiment are not necessarily all indispensable, and at least a person skilled in the art appropriately selects them without departing from the scope of the present invention. It is possible.

  For example, in the above example, the steam in the fourth extraction line L9d is used as the steam for heating the drying air, and the steam in the second extraction line L9b is used as the steam for preheating the combustion air. Of course, other steam can be used as the steam for heating the drying air or the steam for preheating the combustion air according to the change in the position or the number of the extracted air in the low-pressure steam turbine 102.

  In addition, in the power generation system 1, the steam from the plurality of extraction lines can be used as the steam for heating the drying air or the steam for preheating the combustion air, and the plurality of steams can be used depending on the degree of heating or preheating. The supply amount (supply balance) of steam from the extraction line may be controlled.

1: Woody biomass fuel power generation system 2: Receiving equipment 3: Combustion equipment 4: Power generation equipment 9: Fuel storage 10: First conveyor 11: Dryer 12: Drying fan 13: Heat exchanger 21: Receiving hopper 22: Storage container 23: Vent 25: Second conveyor 31: Boiler 32: Air preheater 41: Combustion chamber 42: Boiler body 43: Cyclone 44: Convection heat transfer chamber 45: Seal pot 51: Fuel feeder 52: Fuel tank 53: Pump 54: Burner 61: Evaporation pipe 62: Tertiary superheater 63: Steam drum 65: Primary superheater 71: Secondary superheater 72: Reheater 73: Charcoal saver 75: Discharge passage 81: Fly ash transport pipe 82: Gas Circulation pipe 85: Fourth superheater 90: Preheater body 91: First heat transfer pipe 92: Second heat transfer pipe 93: First combustion blower 94: Second combustion blower 95: First auxiliary preheater 96: Second Auxiliary preheater 101: high-pressure steam turbine 102: low-pressure steam turbine 103: generator 104: condenser 105: deaerators 106a to 106e: first to fifth feed water heaters

Claims (9)

A woody biomass power generation system for generating power using woody biomass as a fuel,
A dryer to dry the fuel,
An air preheater for preheating combustion air,
A boiler that burns the fuel dried by the dryer using the combustion air,
At least one steam turbine for power generation driven by steam heated by the boiler;
Equipped with
The dryer dries the fuel by heat of the first extracted steam extracted from the steam turbine for power generation,
The air preheater preheats the combustion air by the heat of the second extraction steam that is taken out from the power generation steam turbine and has a temperature higher than that of the first extraction steam. system. A blower for supplying drying air,
A heat exchanger that heats the drying air introduced into the dryer by heat exchange between the first extraction steam and the drying air;
The woody biomass fuel power generation system according to claim 1, further comprising:   The temperature of the said drying air introduce|transduced into the said dryer exists in the range of 120 degreeC-150 degreeC, The wood biomass fuel power generation system of Claim 2 characterized by the above-mentioned.   The dryer is provided with a storage container that stores the fuel and into which the drying air is introduced, and a vent that discharges the drying air containing the moisture of the fuel from the storage container. The woody biomass fuel power generation system according to claim 2 or 3.   The temperature of the combustion air introduced into the boiler from the air preheater is in the range of 200° C. to 250° C. 5. The woody biomass fuel power generation according to claim 1. system. The steam turbine for power generation includes a high-pressure steam turbine driven by the higher-pressure steam, and a low-pressure steam turbine driven by the lower-pressure steam supplied via the high-pressure steam turbine,
The wood biomass fuel power generation system according to any one of claims 1 to 5, wherein the first and second extracted steams are extracted from the low-pressure steam turbine. Further comprising a condenser attached to the steam turbine for power generation,
The woody biomass fuel power generation according to any one of claims 1 to 6, wherein the first extracted steam used for drying the fuel in the dryer is circulated to the condenser. system.   8. The fuel according to claim 1, wherein the fuel contains 40 to 50% by weight of water before being dried by the dryer, and contains 20% by weight or less of water after being dried by the dryer. A woody biomass fuel power generation system described in Crab. A woody biomass power generation method for generating power using woody biomass as a fuel,
A drying step for drying the fuel,
An air preheating step for preheating combustion air,
A combustion step of burning the fuel dried by the drying step using the combustion air,
A power generation step of driving at least one power generation steam turbine with steam heated by combustion heat in the combustion step;
Have
In the drying step, the fuel is dried by the heat of the first extraction steam extracted from the power generation steam turbine,
In the air preheating step, the combustion air is preheated by the heat of the second extraction steam extracted from the power generation steam turbine and having a temperature higher than that of the first extraction steam. Method.

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