JP2012102711A - Temperature reducing device steam heat recovery facilities - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a practical temperature reducing device steam heat recovery facilities, provided at a steam power generating plant and recovering and effectively utilizing heat of steam sent out from a temperature reducing device after boiler starting until usual load operation.SOLUTION: The temperature reducing device steam heat recovery facilities, which are provided at the steam power generating plant and recover heat of steam sent out from the temperature reducing device 55 after the boiler starting until the usual load operation, include: a boiler supply water heating steam system 41 connecting the temperature reducing device 55 to a boiler supply water system and sending steam, sent out from the temperature reducing device 55, to a deaerator 30 as a heating steam of a boiler supply water; a condensed water recovering system 42 connecting the temperature reducing device 55 to a condenser 21 and sending steam and/or drain sent out from the temperature reducing device 55 to the condenser 21; and a three-way valve 43 capable of switching two systems of the boiler supply water heating steam system 41 and/or the condensed water recovering system 42 so as to introduce the steam sent out from the temperature reducing device 55 to the two systems and distributing steam amounts to the two systems.

Description

  The present invention relates to a desuperheater steam heat recovery facility for recovering the heat of steam sent from a desuperheater until the normal load operation after a boiler is started in a steam power plant.

  Conventional general steam power plants use coal, heavy oil, LNG, or the like as fuel to generate steam in a boiler, and the generated steam is guided to a steam turbine to drive a generator to generate power. The steam that drives the steam turbine is cooled by a condenser using seawater as a cooling medium to become condensed water. This condensate becomes boiler feed water and is heated by a low pressure feed water heater, and further, dissolved oxygen and the like in the feed water is removed by a deaerator and then heated by a high pressure feed water heater and sent to the boiler. The steam extracted from the steam turbine is used to heat the low-pressure feed water heater, the deaerator, and the high-pressure feed water heater.

  When starting up a steam power plant, it is necessary to supply about 25% of the boiler's rated water supply to protect the boiler water wall of the boiler. On the other hand, even if the boiler is started, the generated steam cannot be immediately supplied to the steam turbine. In order to supply steam to the steam turbine, it is necessary to maintain the steam at a specified temperature and pressure. Further, after the steam is supplied to the steam turbine, the amount of steam is gradually increased, and finally all the generated steam is supplied to the steam turbine. It will be. As described above, since the boiler water supply amount and the steam supply amount to the steam turbine are different at the startup of the steam power plant, the steam power plant is provided with a startup bypass device, and surplus steam is condensed into the condensate via the flash tank. Led to the vessel.

  In the past, many proposals have been made for power generation efficiency, effective use of energy, energy saving, and reduction of running costs in a steam power plant. Proposals for such effective use of energy include not only those corresponding to normal operation but also those corresponding to startup bypass operation. For example, when a steam power plant is started, a warming operation is required in which steam generated by igniting a boiler is gradually sent to various places such as a main steam pipe using a startup bypass device to raise the temperature to a predetermined temperature. Conventionally, steam used for this warming has been discharged to the outside without being effectively used, but proposals have been made for effectively using the steam used for this warming (for example, Patent Documents 1 and 2). reference).

JP 2009-7954 A JP 2009-293871 A

  In a steam power plant, improvement of power generation efficiency, reduction of running costs, etc. should be said to be eternal issues, and further improvements are expected in the future. For example, in a steam power plant equipped with a start-up bypass device, the warm-up operation of the main steam pipe is performed using the start-up bypass device at the time of start-up. After being led to a vessel and reduced to a predetermined temperature, it is sent to a condenser to be condensed. Such an exhaust steam processing method is a simple processing method, but has not led to effective utilization. The steam exhausted by warming the main steam pipe has a high temperature and can be used effectively. However, the steam exhausted to the temperature reducer and the steam delivered from the temperature reducer have received little attention. No effective use method has been proposed.

  An object of the present invention is to provide a practical desuperheater steam heat recovery facility that is provided in a steam power plant and recovers and effectively uses the heat of steam sent from the desuperheater until the normal load operation after the boiler is started. It is to be.

  The present invention relates to a boiler, a steam turbine driven by steam delivered from the boiler, a condenser for condensing exhaust steam from the steam turbine, a low-pressure feed water heater, a deaerator, and a high-pressure feed water heater. A boiler water supply system that heats the condensate delivered from the condenser and supplies the boiler with water, and after starting the boiler, water is supplied until a predetermined steam is supplied to the steam turbine and switched to a normal load operation. The steam generator is provided in a steam power plant comprising: a startup bypass device that circulates steam and delivers exhausted steam and / or drain to the condenser through a desuperheater and uses it as condensate And a steam heat recovery facility for recovering steam heat sent from the temperature reducer until normal load operation, connecting the temperature reducer and the boiler water supply system, from the temperature reducer The steam to be delivered The boiler feed water heating steam system that is sent to the boiler feed water system as steam for heating the feed water is connected to the temperature reducer and the condenser, and the steam and / or drain sent from the temperature reducer is returned to the condenser. The two systems can be switched so as to guide the steam sent from the desuperheater to the condensate recovery system to be sent to the water device, the boiler feed water heating steam system and / or the condensate recovery system, And a system controller that can distribute the amount of steam to the system.

  Moreover, the present invention is characterized in that, in the desuperheater steam heat recovery facility, the boiler feed water heating steam system connects the desuperheater and the boiler feed water system downstream of the deaerator or the deaerator. And

  Further, the present invention is the above-described desuperheater steam heat recovery facility, wherein the boiler feed water heating steam system is branched into a plurality of parts on the way, and the branched tip ends are connected to a plurality of locations of the boiler water supply system. It is formed so that steam can be delivered to one or more locations of the system, and further includes a control device that controls the steam delivery destination of the boiler feed water heating steam system.

  Further, the present invention provides the desuperheater steam heat recovery facility, wherein the control device has the highest steam temperature below the steam temperature at which the boiler feed water temperature of the delivery destination is less than the delivery temperature of the plurality of steam delivery destinations. A near steam delivery destination is selected, and the boiler feed water heating steam system is controlled so as to deliver steam to the steam delivery destination.

  Further, the present invention is characterized in that, in the desuperheater steam heat recovery facility, the steam power plant is a steam power plant that supports weekend start / stop (WSS) operation or midnight start / stop (DSS) operation.

  Since the desuperheater steam heat recovery equipment of the present invention includes a boiler feed water heating steam system capable of delivering steam delivered from the desuperheater to the boiler feed water system after the boiler is started until the normal load operation, the steam is used in the boiler. The feed water can be heated, and the steam delivered from the temperature reducer can be used effectively. Also, a system that can send out the steam sent from the temperature reducer to the condenser, two systems can be switched, and system control means that can distribute the amount of steam to the two systems is provided. Steam that is not sent to the boiler feed water heating steam system can be sent to the condenser. Thereby, all the steams sent from the temperature reducer can be reliably processed, and the start-up operation of the steam power plant can be performed without any trouble.

  Further, according to the present invention, the boiler feed water heating steam system can guide the delivery steam from the desuperheater to the deaerator or the boiler feed water system on the downstream side of the deaerator. The water level of the deaerator is raised by bringing the drain generated by direct contact with the feed water or heat exchange with the boiler feed water into the deaerator. As a result, the amount of water supplied to the deaerator is reduced, the load of the condensate pump and the condensate booster pump for supplying boiler feed water is reduced, and the running cost thereof is reduced.

  Further, according to the present invention, the boiler feed water heating steam system is divided into a plurality of parts on the way, is formed so as to be able to send steam to one or more locations of the boiler feed water system, and further, the steam delivery destination of the boiler feed water heating steam system Therefore, it is possible to send steam delivered from the temperature reducer to a plurality of locations in the boiler water supply system. By sending steam to several places in the boiler water supply system, the steam consumption increases and the amount of steam sent to the condenser decreases, so the steam sent from the temperature reducer can be used more effectively. .

  Further, according to the present invention, the control device sends steam from a plurality of steam destinations to a steam destination closest to the steam temperature below the steam temperature at which the boiler feed water temperature of the destination is sent. Since the boiler feed water heating steam system is controlled, the heat of the steam delivered from the temperature reducer can be efficiently utilized by heating the boiler feed water. Low temperature boiler feedwater can be heated with low temperature steam, but high temperature boiler feedwater cannot be heated with low temperature steam. It is.

  Further, according to the present invention, the desuperheater steam heat recovery facility of the present invention relates to the treatment of steam exhausted at the start of a steam power plant, so weekend start / stop (WSS) operation with many start / stops, midnight It can be suitably used for a steam power plant that performs start / stop (DSS) operation.

It is a process flow figure showing a schematic structure of a steam power generation plant provided with a desuperheater steam heat recovery equipment as a 1st embodiment of the present invention. It is a process flow figure showing a schematic structure of a desuperheater steam heat recovery equipment as a 2nd embodiment of the present invention. It is a process flow figure showing a schematic structure of a desuperheater steam heat recovery equipment as a 3rd embodiment of the present invention.

  FIG. 1 is a process flow diagram showing a schematic configuration of a steam power plant including a desuperheater steam heat recovery facility as a first embodiment of the present invention. First, the overall configuration of the steam power plant will be described in accordance with the flow of steam and condensate / feed water during normal operation (normal load operation), and then the configuration of the startup bypass device, the operating procedure and steam cooler steam when starting the steam power plant How to use the heat recovery equipment will be explained.

  The boiler 1 includes a furnace 2 that burns LNG (liquefied natural gas) as fuel, a economizer 3 that heats boiler feed water using the combustion gas, a water cooling wall 4, a gauge wall 5, and saturated steam as primary steam. A superheater 6 and a secondary superheater 7 are provided. The superheated steam delivered from the secondary heater 7 is sent to the high-pressure turbine 14 through the main steam pipe 13 provided with the main steam stop valve 11 and the steam control valve 12 to drive the high-pressure turbine 14. The steam that has driven the high-pressure turbine 14 is reheated by a boiler reheater (not shown), and then drives an intermediate-pressure turbine and a low-pressure turbine that are not shown. The generator (not shown) is connected to the high-pressure turbine 14, the intermediate-pressure turbine, and the low-pressure turbine, and is driven by these turbines to generate power.

  The steam discharged from the low-pressure turbine is cooled and condensed by the condenser 21 to become condensed water. Condensate is sent to a desalinator 23 via a condensate pump 22 to remove salts in the condensate. The condensate from which salts have been removed is boosted by the condensate booster pump 24 and then heat-exchanged with the axial cold water by the condensate heat exchanger 25 to increase the temperature. Thereafter, the condensate is used as a refrigerant for the cooler of the air extraction device 26, sent in the order of the ground condenser 27 and the drain cooler 28, further heated by the low-pressure feed water heater 29, and then sent to the deaerator 30.

  The low-pressure feed water heater 29 is a surface contact type heat exchanger, and is heated by extracted steam of a low-pressure turbine (LP). Three low-pressure feed water heaters 29 are provided in series, and only one is shown in FIG. The feed water sent to the deaerator 30 is heated by the extraction steam (deaeration steam) of the intermediate pressure turbine, and after the non-condensable gas such as dissolved oxygen in the feed water is removed, the pressure is increased by the boiler feed pump 31. After that, it is sent to the high-pressure feed water heater 32 where it is further heated by the extracted steam of the high-pressure turbine 14. The high-pressure feed water heater 32 (32 a, 32 b, 32 c) is a surface contact type heat exchanger, and feed water heated by the extraction steam of the high-pressure turbine 14 is sent to the economizer 3. A system from the condenser 21 to the economizer 3 is a condensate / water supply system.

  The desuperheater steam heat recovery facility is a facility for using the steam delivered from the desuperheater 55 of the startup bypass device described later after boiler 1 startup until the normal load operation for heating boiler feed water. The desuperheater steam heat recovery equipment is a boiler feed water heating steam system 41 that guides steam delivered from the desuperheater 55 of the startup bypass device to the deaerator 30, drain and / or steam delivered from the desuperheater 55. A condensate recovery system 42 that leads to the condenser 21 and a three-way valve 43 that guides steam delivered from the temperature reducer 55 to the boiler feed water heating steam system 41 and / or the condensate recovery system 42 are provided. The outlet portion of the temperature reducer 55 and the inlet portion of the three-way valve 43 are a conduit 44, one outlet of the three-way valve 43 and the deaerator 30 are a conduit 45, and the other outlet of the three-way valve 43 and condensate. The vessel 21 is connected by a pipe 46, and a boiler feed water heating steam system 41 is formed by the pipe 44 and the pipe 45 with the three-way valve 43 therebetween, and the pipe 44 and the pipe with the three-way valve 43 interposed therebetween. 46, a condensate recovery system 42 is formed. The three-way valve 43 is supplied to the boiler feed water heating steam system 41 so that the feed water temperature in the deaerator 30 becomes a predetermined temperature based on a command from an operation control device (not shown) that controls the operation of the steam power plant. Adjust the amount of steam delivered. Instead of the three-way valve 43, a flow rate adjusting valve may be provided in the pipe line 45 and the pipe line 46 to adjust the steam amount to the boiler feed water heating steam system 41 and the condensate recovery system 42.

  The steam power plant is provided with a startup bypass device used when starting up. The startup bypass device includes a primary superheater bypass system 51 that bypasses the primary superheater 6, a secondary superheater bypass system 52 that bypasses the secondary superheater 7, a primary superheater bypass system 51, and a secondary superheater bypass. A flash tank 53 disposed so as to be connected to the system 52 and bypassing the primary superheater 6, a turbine bypass system 54 disposed upstream of the high-pressure turbine 14, surplus steam exhausted from the flash tank 53 and the turbine A temperature reducer 55 for reducing the temperature of steam exhausted from the bypass system 54 is provided.

  The primary superheater bypass system 51 has a primary superheater bypass pipe 56 that connects the upstream side of the primary superheater 6 and the flash tank 53, and includes a regulating valve 57 in the middle of the pipeline. Similarly to the primary superheater bypass system 51, the secondary superheater bypass system 52 has a secondary superheater bypass pipe 58 that connects the upstream side of the secondary superheater 7 and the flash tank 53, and is in the middle of the pipeline. A regulating valve 59 is provided. Further, the secondary superheater bypass system 52 includes a secondary heater warming pipe 61 that warms the secondary superheater 7 with steam delivered from the flash tank 53 and is provided with a heater vent valve 60.

  The flash tank 53 is a pressure vessel that receives steam exhausted through the primary superheater bypass pipe 56 and the secondary superheater bypass pipe 58 and adjusts the steam to a predetermined pressure, and sends the steam to the secondary superheater 7. At the same time, the heating steam is sent to the deaerator 30 and the high-pressure feed water heater 32c through the heating steam pipe 62 provided with the regulating valves 67 and 68 for heating the boiler feed water. The flash tank 53 is provided with a dump steam valve 63 that opens and escapes steam at a predetermined pressure or higher, and the dump steam is passed through a dump steam delivery pipe 64 provided with a shut-off valve 69 connected to the temperature reducer 55. 55. The heating steam pipe 62 is connected to the dump steam delivery pipe 64 on the upstream side of the dump steam valve 63. Further, the flush tank 53 includes drain delivery pipes 65 and 66 provided with adjusting valves 70 and 71 for delivering the generated drain to the condenser 21 and the deaerator 30. Further, the drain delivery pipe 65 is provided with a branch pipe 73 having an adjustment valve 72 communicating with the blow tank.

  The turbine bypass system 54 has a turbine bypass pipe 76 provided with a turbine bypass valve 75, and one end is connected to the main steam pipe 13 on the upstream side of the main steam stop valve 11 and the other end is connected to the temperature reducer 55.

  The temperature reducer 55 is a device that reduces the temperature of the dump steam in the flash tank 53 and the warming steam in the main steam pipe 13 exhausted through the turbine bypass pipe 76. Condensate is supplied to the temperature reducer 55 as water for temperature reduction through a temperature-reduced water supply pipe 77 having an adjustment valve 78 provided at the outlet of the condensate booster pump 24. A temperature detector 80 is attached to the temperature reducer 55, and the adjustment valve 78 adjusts the amount of water to be reduced by a signal from a temperature controller 81 connected to the temperature detector 80. Thereby, the steam discharged from the temperature reducer 55 is adjusted to a predetermined temperature.

  Next, an operation procedure when starting the steam power plant and a boiler feed water heating method using steam delivered from the temperature reducer 55 will be described. In addition, the numerical value used for the following description is an illustration, and this invention is not restrained by this numerical value.

  When starting a steam power plant, in order to protect the water cooling wall 4 of the boiler 1, it is necessary to supply about 25% of the boiler's rated water supply amount. On the other hand, since the generated steam cannot be immediately supplied to the steam turbine even when the boiler 1 is activated, the steam power plant is activated by the activation bypass operation using the activation bypass device. The boiler 1 is supplied with about 25% of the boiler rated water supply amount until the startup bypass operation is completed.

  After water filling of the boiler 1, system water circulation is performed through the boiler 1, the primary superheater bypass system 51, the flash tank 53, and the condensate / water supply system. At this time, the superheater stop valve 8, the superheater control valve 9, and the secondary superheater bypass system 52 that connect the primary superheater 6 and the secondary superheater 7 are closed. After the boiler is ignited, the steam is sent to the flash tank 53 through the primary superheater bypass system 51, and when the inlet temperature of the primary superheater 6 reaches 160 ° C, the regulating valve 59 of the secondary superheater bypass system 52 is opened. The superheater 6 is heated. Thereafter, a part of the steam sent to the flash tank 53 other than that used for warming or the like becomes a drain and is sent to the condenser 21 and the deaerator 30, and the surplus steam is sent to the deaerator. 30 is sent to the high pressure feed water superheater 32 and used for heating boiler feed water. Further, when the flash tank pressure exceeds 3.5 MPa, the dump steam valve 63 is opened, and surplus steam is sent to the temperature reducer 55.

  When the flash tank pressure becomes 0.98 MPa, the heater vent valve 60 and the turbine bypass valve 75 are opened, and the steam flows into the secondary superheater 7 and the main steam pipe 13 to be warmed. The warming of the main steam pipe 13 is continued until the flash tank pressure reaches about 3.5 MPa. The steam warming the main steam pipe 13 is sent from the turbine bypass pipe 76 to the temperature reducer 55.

  When the warming of the main steam pipe 13 is finished, the turbine bypass valve 75 is closed, and the steam is sent to the steam turbine 14 to be paralleled. After paralleling the steam turbine, the superheater pressure reducing valve 9 is opened, steam is supplied via the superheater pressure reducing valve 9, the opening degree of the heater pressure reducing valve 9 is gradually increased, and the main steam pressure is set to 15.576 MPa. This operation is called a ramping operation. Even in this state, a part of the steam is sent to the flash tank 53. At this stage of operation, the superheater stop valve 8 is fully opened. Thereafter, valve switching is performed in which the steam is controlled by the steam control valve 12 from the main steam stop valve 11, and all the steam is sent to the high-pressure turbine 14. At this time, since it is not necessary to flow steam to the startup bypass system, the regulating valve 57 of the primary superheater bypass system 51 is closed, the startup bypass operation is completed, and the operation shifts to the normal operation (normal load operation). Operation using the startup bypass system is also called low-load operation.

  The surplus steam from the flash tank 53 sent to the cooler 55 and the steam sent from the turbine bypass pipe 76 and warmed through the main steam pipe 13 are reduced when the steam temperature exceeds the set temperature of the cooler 55. After being adjusted to a set temperature, for example, 170 ° C. by the vessel 55, it is sent to the deaerator 30 through the boiler feed water heating steam system 41 to heat the feed water to the set temperature. When the amount of steam required for heating the feed water of the deaerator 30 is small and not all the steam sent from the temperature reducer 55 can be sent to the deaerator 30, the surplus steam passes through the condensate recovery system 42. 21 sent to condensate. Adjustment of the delivery of steam to the boiler feed water heating steam system 41 and the condensate recovery system 42 is performed by the three-way valve 43, and all the steam sent from the temperature reducer 55 is the boiler feed water heating steam system 41 and / or condensate. It is processed through the recovery system 42.

  In the initial stage of warming of the main steam pipe 13, the temperature of the steam sent to the temperature reducer 55 may be low, or the steam may be drained and sent to the temperature reducer 55. When the temperature of the temperature reducer 55 is compared with the feed water temperature in the deaerator 30 and the temperature of the temperature reducer 55 is low, all the steam and / or drain sent to the temperature reducer 55 is recovered from the condenser 21. The three-way valve 43 is switched so as to be sent to

  In the conventional steam power plant, all the steam exhausted to the temperature reducer 55 during the start-up bypass operation is finally sent to the condenser 21 to be condensate, and heat recovery is not performed. On the other hand, in the steam power generation plant shown in the present embodiment, the steam discharged from the temperature reducer 55 that is exhausted to the temperature reducer 55 during start-up bypass operation and reduced in temperature as needed is used for feed water heating. Therefore, the thermal energy possessed by the exhaust steam can be used effectively. The steam sent to the deaerator 30 is steam whose temperature has been adjusted by the temperature reducer 55, and further, the dump steam of the flash tank 53 and the warming steam of the main steam pipe 13 exhausted through the turbine bypass pipe 76. By sending the heat to the deaerator 30 via the temperature reducer 55, fluctuations in the steam flow rate are alleviated, and the feed water heating controllability of the deaerator 30 is facilitated. Further, when the amount of steam required for heating the feed water of the deaerator 30 is small, surplus steam is sent to the condenser 21, so that the start-up bypass operation of the steam power plant can be performed without any trouble. Moreover, since the deaerator 30 is a direct heating type, the steam sent to the deaerator 30 is cooled by feed water and becomes condensed water. As a result, the water level of the deaerator 30 rises and the amount of water supplied to the deaerator 30 decreases. As a result, the loads on the condensate pump 22 and the condensate booster pump 24 that feed water to the deaerator 30 are reduced, and the running costs thereof are reduced.

  FIG. 2 is a process flow diagram showing a schematic configuration of a desuperheater steam heat recovery facility as a second embodiment of the present invention. The same code | symbol is attached | subjected to the structure same as the desuperheater steam heat recovery equipment shown in 1st Embodiment, and description is abbreviate | omitted.

  Similarly to the desuperheater steam heat recovery facility shown in the first embodiment, the desuperheater steam heat recovery facility shown in the second embodiment is exhausted to the desuperheater 55 of the startup bypass device during the startup bypass operation, as necessary. This is a facility for using the steam delivered from the temperature reducer 55 for heating the feed water, and includes a boiler feed water heating steam system 47, a condensate recovery system 42, and a three-way valve 43. However, in the desuperheater steam heat recovery facility shown in the second embodiment, a plurality of boiler feed water heating steam systems 47 are provided, and a control device 100 that controls the delivery of steam to the plurality of boiler feed water heating steam systems 47 is provided. However, it differs from the desuperheater steam heat recovery equipment shown in the first embodiment. Hereinafter, the difference from the desuperheater steam heat recovery facility shown in the first embodiment will be mainly described.

  In the boiler feed water heating steam system 47, the pipe 45 at the outlet of the three-way valve 43 branches into four, and first to fourth pipes 49a, 49b, 49c, and 49d are provided at the branched tip. Two boiler feed water heating steam systems 47a, 47b, 47c, 47d are formed. The first pipe line 49 a includes a shutoff valve 50 a at an end, is connected to the pipe 45 via the shutoff valve 50 a, and is connected to the deaerator 30 at the other end. The second pipe line 49b includes a shutoff valve 50b at an end, is connected to the pipe line 45 through the shutoff valve 50b, and is connected to the high pressure feed water heater 32a at the other end. The third pipe line 49c is provided with a shutoff valve 50c at an end, is connected to the pipe 45 via the shutoff valve 50c, and is connected to the high pressure feed water heater 32b at the other end. The fourth pipe line 49d includes a shutoff valve 50d at an end, is connected to the pipe 45 via the shutoff valve 50d, and is connected to the high pressure feed water heater 32c at the other end. The boiler feed water heating steam system 47a is formed by a pipeline 44, a pipeline 45, a shutoff valve 50a, and a pipeline 49a with the three-way valve 43 interposed therebetween. The same applies to the other boiler feed water heating steam systems 47b, 47c, and 47d, and the pipeline 44 and the pipeline 45 sandwiching the three-way valve 43 are shared portions. The shut-off valves 50 (50a, 50b, 50c, 50d) are opened and closed by a signal from the control device 100.

  The control device 100 is connected to an operation control device (not shown) for controlling the operation of the steam power plant so that signals can be transmitted and received, and cooperates with the operation control device to provide a plurality of boiler feed water heating steam systems 47 (47a, 47b). 47c, 47d), the boiler feed water heating steam system 47 that supplies steam is selected, and the three-way valve 43 and the shutoff valve 50 are controlled so as to send the steam to the selected boiler feed water heating steam system 47. The control device 100 obtains temperature data from the operation control device, and from this temperature data, the boiler feed water heating steam system 47a, the supply water temperature of the delivery destination being a temperature equal to or lower than the temperature reducer 55 and closest to the temperature reducer 55, 47b, 47c, 47d are selected, and control is performed so that steam is delivered to the boiler feed water heating steam system 47. Further, even if steam is supplied only to the boiler feed water heating steam system 47 selected earlier, when the steam delivered from the temperature reducer 55 is excessive, the temperature is not more than the temperature reducer 55 and then to the temperature reducer 55. A boiler feed water heating steam system 47 having a close feed water temperature is selected, and control is performed so that steam is also sent to the boiler feed water heating steam system 47. Similarly, the steam can be controlled so as to be sent to the third and fourth boiler feed water heating steam systems 47. In addition, when all the steam sent from the temperature reducer 55 cannot be sent to the deaerator 30 and / or the high-pressure feed water heaters 32a, 32b, 32c, the surplus steam is sent to the condensate recovery system 42. This is the same as the desuperheater steam heat recovery equipment shown in the first embodiment.

  The low temperature water supply can be heated even with the low temperature steam, but it goes without saying that the high temperature water supply cannot be heated with the low temperature steam. Since the hot water supply can be heated only by steam having a temperature higher than that, the heating method for boiler feed water shown in the present embodiment can be said to be an efficient method. Further, when steam is supplied to the boiler feed water heating system 47 whose supply water temperature is lower than the temperature reducer 55 and closest to the temperature reducer 55 as in this embodiment, the temperature difference between the water supply temperature and the steam temperature. This is preferable because it can avoid or suppress adverse effects on the apparatus due to temperature differences, such as thermal deformation. Moreover, since it may be controlled so that steam is simultaneously sent to two or more boiler feed water heating steam systems 47, for example, the deaerator 30 and the high pressure feed water heater 32a, the steam delivery amount increases and the condenser is increased. The steam released to 21 can be reduced, and the delivered steam can be used more effectively.

  FIG. 3 is a process flow diagram showing a schematic configuration of a desuperheater steam heat recovery facility as a third embodiment of the present invention. The same components as those of the desuperheater steam heat recovery facility shown in the first embodiment and the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Similarly to the desuperheater steam heat recovery facility shown in the first embodiment, the desuperheater steam heat recovery facility shown in the third embodiment is exhausted to the desuperheater 55 of the startup bypass device during the startup bypass operation. This is a facility for using the steam discharged from the temperature reducer 55 for heating the feed water, and includes a boiler feed water heating steam system 41, a condensate recovery system 42, and a three-way valve 43. However, in the desuperheater steam heat recovery facility shown in the third embodiment, a heat exchanger 90 for heat recovery is newly provided between the boiler feed water pump 31 and the high-pressure feed water heater 32a. A boiler feed water heating steam system 41 is provided so as to guide steam delivered from the temperature reducer 55. Hereinafter, the difference from the desuperheater steam heat recovery facility shown in the first embodiment will be mainly described.

  The heat exchanger 90 is a surface contact type heat exchanger, and the steam sent through the boiler feed water heating steam system 41 heats the boiler feed water, becomes drain, and is sent to the drain tank 91. A drain pipe 93 is connected to the drain tank 91 to send the drain to the condenser 21 via the drain heater 28. The drain pipe 93 is provided with a drain pump 92 and a flow rate adjusting valve 94. The drain exchanges heat with the feed water by the drain heater 28, heats the feed water, and is sent to the condenser 21. The supply procedure of the steam delivered from the temperature reducer 55 to the heat exchanger 90, the configuration of the boiler feed water heating steam system 41, and the like are not different from the temperature reducer steam heat recovery equipment shown in the first embodiment.

  Unlike the desuperheater steam heat recovery equipment shown in the first and second embodiments, the desuperheater steam heat recovery equipment shown in the third embodiment supplies steam to the deaerator 30 or the high-pressure feed water heater 32. Therefore, there is no need to modify these devices, and there is no need to change the operating procedure.

  As shown in the above embodiment, the desuperheater steam heat recovery facility according to the present invention can effectively use the steam sent from the desuperheater at the start of the steam power plant for heating the boiler feedwater, Since it is equipped with a system that collects it as condensate when it cannot be used for heating the feedwater, it is a practical facility that does not interfere with the startup bypass operation. Moreover, since the configuration is relatively simple, it can be easily applied to existing steam power plants as well as newly installed power plants.

  In a steam power plant that frequently performs midnight start / stop (DSS) operation and weekend start / stop (WSS) operation, the ratio of start bypass operation to normal operation is large, and the amount of steam exhausted to the temperature reducer 55 increases. It is effective to provide the desuperheater steam heat recovery equipment of the present invention for such a steam power plant.

  In addition, this invention is not limited to the said embodiment, It can change and use for various embodiment in the range which does not change a summary. In the above embodiment, the temperature-reducing water is supplied to the temperature-reducing device 55, and the steam delivered from the temperature-reducing device 55 is adjusted to a predetermined temperature and then delivered. However, if necessary, the temperature-reducing water is supplied. You may make it stop and send steam with high temperature to a boiler feed water heating steam system. Further, a boiler feed water heating steam system for sending steam to the low pressure feed water heater 29 may be provided to recover heat. In the above embodiment, the steam exhausted to the temperature reducer 55 is surplus steam from the flash tank 53 and exhaust steam from the turbine bypass system 54, but the steam exhausted to the temperature reducer 55 is limited to this. Is not to be done. For example, when a steam ejector is used for the air extraction device 26, an ejector main steam pipe that normally sends driving steam from the main steam pipe 13 is provided in the steam ejector. Blow is performed. In a steam power plant in which this blow steam is exhausted to the temperature reducer 55, such exhaust steam can also be recovered and used effectively by the temperature reducer steam heat recovery facility according to the present invention.

DESCRIPTION OF SYMBOLS 1 Boiler 14 High pressure turbine 21 Condenser 29 Low pressure feed water heater 30 Deaerator 32, 32a, 32b, 32c, 32d High pressure feed water heater 41 Boiler feed water heating steam system 42 Condensate recovery system 43 Three-way valve 44 Pipe 45 Pipe Line 46 Pipe lines 47, 47a, 47b, 47c, 47d Boiler feed water heating steam systems 49a, 49b, 49c, 49d Pipe lines 50a, 50b, 50c, 50d Shut-off valve 55 Temperature reducer 77 Temperature-reducing water supply pipe 78 Regulating valve 80 Temperature Detector 81 Temperature controller 90 Heat exchanger 100 Controller

Claims (5)

With a boiler,
A steam turbine driven by steam delivered from the boiler;
A condenser for condensing exhaust steam of the steam turbine;
A boiler water supply system comprising a low-pressure feed water heater, a deaerator, and a high-pressure feed water heater, heating the condensate sent from the condenser and feeding the boiler;
After the boiler is started, water and / or steam is circulated until a predetermined steam is supplied to the steam turbine and switched to a normal load operation, and the exhaust steam and / or drain is passed through a temperature reducer to the condenser. A start-up bypass device to be sent to the condensate,
A steam power recovery facility that recovers the heat of steam delivered from the temperature reducer until the normal load operation after the boiler is started,
A boiler feed water heating steam system for connecting the temperature reducer and the boiler feed water system, and sending steam sent from the temperature reducer to the boiler feed water system as steam for heating boiler feed water;
A condensate recovery system for connecting the temperature reducer and the condenser, and sending steam and / or drain sent from the temperature reducer to the condenser;
System control capable of switching between the two systems so as to guide the steam delivered from the desuperheater to the boiler feed water heating steam system and / or condensate recovery system, and capable of distributing the amount of steam to the two systems Means,
A desuperheater steam heat recovery facility comprising:   2. The desuperheater steam heat recovery facility according to claim 1, wherein the boiler feed water heating steam system connects the desuperheater and the deaerator or a boiler feed water system downstream of the deaerator. . The boiler feed water heating steam system is divided into a plurality of parts in the middle, and the branched tip ends are connected to a plurality of locations of the boiler feed water system so that steam can be sent to one or more locations of the boiler feed water system,
3. The desuperheater steam heat recovery facility according to claim 1, further comprising a control device that controls a steam delivery destination of the boiler feed water heating steam system.   The control device selects a steam destination closest to the steam temperature below the steam temperature at which the boiler feed water temperature of the destination is sent out of the plurality of steam destinations, and sends steam to the steam destination. 4. The desuperheater steam heat recovery facility according to claim 3, wherein the boiler feed water heating steam system is controlled so as to be sent out.   The steam generator steam heat according to any one of claims 1 to 4, wherein the steam power plant is a steam power plant that supports weekend start / stop (WSS) operation or midnight start / stop (DSS) operation. Recovery equipment.

Images