JP2012102980A - Blow tank and method of using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow tank and a method of using the same, capable of reducing running costs, and further effectively utilizing heat.SOLUTION: This blow tank 100 disposed in a steam-power generation plant for receiving drainage and/or steam, and cooling and distributing the same to a drainage processing device, includes a tank body 101, a cooling pipe 102 disposed in the tank body 101 and applying steam condensate as a cooling medium, and a cooling water supply means 103 for supplying industrial water into the tank body 101. The cooling pipe 102 is used in preference to the cooling water supply means 103, the steam condensate is distributed to the cooling pipe 102 from an outlet section of a grand condenser, and the steam condensate exchanging heat with the drainage and/or steam, is returned to an inlet section of a drain cooler, thus an amount of drainage is reduced, and further heat can be recovered.

Description

  The present invention relates to a blow tank provided in a steam power plant, receiving drain and / or steam, cooling it and sending it to a wastewater treatment apparatus, and a method of using the blow tank.

  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, during startup bypass operation of a steam power plant, steam and / or drain blown from the upper drain valve of the steam control valve is sent to the turbine flash pipe for gas-liquid separation, and drain is sent from the turbine flash pipe to the blow tank. . Industrial water is added to the drain sent to the blow tank, and the drain whose temperature has been lowered is sent to the waste water treatment apparatus. Although such a treatment method is a simple method, the amount of waste water to be treated increases, and it cannot be said to be a preferable method from the viewpoint of heat recovery. It is thought that the power generation efficiency can be improved and the running cost can be reduced by improving the processing device and processing method for drain and / or steam sent to the blow tank. With regard to steam, little attention has been paid, and no processing apparatus, processing method, etc. that can reduce running costs have been proposed.

  An object of the present invention is to provide a blow tank that can reduce running costs and can effectively use heat, and a method of using the same.

  The present invention is a blow tank that is provided in a steam power plant, receives drain and / or steam, cools it and sends it to a wastewater treatment device, and is provided with the tank body and drain and / or steam provided in the tank body. An indirect cooling means for cooling and using condensate as a cooling medium.

  Further, the present invention is characterized in that the blow tank further includes a second cooling means provided in the tank body for cooling drain and / or steam and using industrial water or seawater as a cooling medium.

  Further, the present invention is a method of using the blow tank, wherein the steam power plant includes at least a condenser for cooling and condensing steam exhaust gas from a steam turbine, a condensate pump for feeding condensate, and a steam ejector. An air extraction device that evacuates the condenser, a ground condenser that exchanges heat between the ground steam and the condensate, and a drain cooler that is located upstream of the low-pressure feed water heater and exchanges heat between the drain and the condensate, These have a condensate system arranged in the above order from the condenser toward the low-pressure feed water heater, send condensate from the outlet of the air extraction device to the indirect cooling means, the drain and The condensate heat-exchanged with steam is returned to the inlet portion of the ground condenser, or condensate is sent from the outlet portion of the ground condenser to the indirect cooling means, and the drain and / or steam and heat are sent. A method using a blow tank and returning the conversion was condensate to the inlet portion of the Dorenkura.

  Further, the present invention is a method of using the blow tank, wherein the drain and / or steam is drain and / or steam blown before and during startup of the steam power plant, and the indirect cooling means is The blow tank is used in preference to the second cooling means, and when the condensate cannot be supplied to the indirect cooling means, the second cooling means is used to cool the drain and / or steam. How to use.

  Further, the present invention is the method of using the blow tank, wherein the steam power plant is evacuated by supplying water and / or steam until a predetermined steam is supplied to the steam turbine and switched to a normal load operation after the boiler is started. And a starting bypass device that sends the steam and / or drain to the condenser through a temperature reducer and uses it as a condensate, and the drain and / or steam blown when starting the steam power plant is the starting bypass. It is the drain and / or steam which are blown at the time of start-up bypass operation using the device.

  Moreover, the present invention is characterized in that, in the method of using the blow tank, the steam power plant is a steam power plant that supports weekend start / stop (WSS) operation or midnight start / stop (DSS) operation.

  In the blow tank of the present invention, since the cooling means for cooling the drain and / or steam is an indirect cooling means, the cooling medium does not become drainage unlike the direct contact cooling method. For this reason, the amount of wastewater to be treated does not increase, and the running cost of the wastewater treatment facility can be reduced. Also, since the cooling medium of the indirect cooling means is condensate, if the condensate whose temperature has been increased by exchanging heat with drain and / or steam is returned to the condensate system, the load on the feed water heater is reduced, The thermal efficiency of the power plant increases.

  According to the invention, the blow tank includes the second cooling means using industrial water or seawater as a cooling medium, so that the drain and / or steam is cooled even before the steam power plant is started. be able to. Since the two cooling means having different cooling media are provided, the blow tank can be operated efficiently.

  In the method of using the blow tank of the present invention, the condensate is sent to the indirect cooling means from the outlet of the air extraction device or the outlet of the ground condenser, so that the temperature of the condensate is relatively low and is preferable as a cooling medium. Condensate has the lowest temperature at the condenser outlet, but condensate is also used as a cooling medium for the air extraction device, so if it is equipped with an air extraction device, Furthermore, it is preferable to send condensate from the outlet of the downstream ground condenser. In addition, since the condensate heat-exchanged with the drain and / or steam is returned to the inlet of the ground condenser or the drain cooler, the temperature of the condensate system rises, the load on the feed water heater is reduced, and the thermal efficiency of the steam power plant increases. .

  Also, the method of using the blow tank of the present invention uses the indirect cooling means in preference to the second cooling means, and uses the second cooling means when the condensate cannot be supplied to the indirect cooling means. The amount of drainage does not increase, and is also preferable from the viewpoint of heat recovery.

  According to the present invention, since the drain and / or steam blown at the start of the steam power plant is the drain and / or steam blown at the start-up bypass operation, the blown drain and / or steam is relatively Many. However, since it can be cooled by the indirect cooling means, the amount of wastewater to be processed does not increase, and heat can be recovered, and the blow tank of the present invention is preferably used in a steam power plant equipped with a startup bypass device. Can do.

  Moreover, since the blow tank of the present invention relates to the treatment of drain and / or steam blown at the start of a steam power plant, weekend stop start (WSS) operation and midnight stop start (DSS) operation with many start and stop are performed. It can use suitably for the steam power plant to perform.

It is a figure which shows the structure of the blow tank as 1st Embodiment of this invention. It is a process flow figure showing a schematic structure of a steam power plant provided with a blow tank of Drawing 1.

  FIG. 1 is a diagram showing a configuration of a blow tank as a first embodiment of the present invention. FIG. 2 is a process flow diagram showing a schematic configuration of a steam power plant including a blow tank. In FIG. 2, a part of the structure around the blow tank is omitted. First, the overall configuration of the steam power plant will be explained according to the flow of steam, condensate and water supply during normal operation (normal load operation), then the configuration of the blow tank, the operating procedure when starting the steam power plant, and how to use the blow tank 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 a cooler of the air extraction device 26, and is sent in the order of a ground condenser 27 for exchanging heat between the ground steam and the condensate, and a drain cooler 28 for exchanging heat between the drain and the condensate. After being heated by the feed water heater 29, it is 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). 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. Then, it is sent to the high-pressure feed water heater 32 where it is further heated. The high pressure feed water heater 32 is a surface contact type heat exchanger, and feed water heated by the extracted steam of the high pressure turbine 14 is sent to the economizer 3. The system from the condenser 21 to the economizer 3 is a condensate / water supply system, and the system from the condenser 21 to the low-pressure feed water heater 29 is a condensate system.

  The air extraction device 26 exhausts the non-condensable gas contained in the turbine exhaust steam brought into the condenser 21 and the air leaking from outside the system, and maintains the inside of the condenser 21 at a low pressure (vacuum). The air extraction device 26 includes a steam-driven ejector, and the main steam of the boiler 1 is supplied through the ejector main steam system 40 as the working steam of the ejector. The ejector main steam system 40 includes an ejector main steam pipe 41. The ejector main steam pipe 41 is provided with an ejector main steam valve 42 and a pressure adjustment valve 43, and adjusts the main steam of the boiler 1 to a specified pressure. Supply to ejector. The ejector main steam pipe 41 is provided with a blow pipe 45 having an ejector main steam drain valve 44 on the upstream side of the ejector main steam valve 42, and the ejector main steam pipe 41 is supplied with warmed and flushed steam and / or drain. Send to turbine flush pipe 47.

  The blow tank 100 includes a high-temperature drain and / or steam sent from the turbine flash pipe 47, a high-temperature drain and / or steam sent from the flash tank 53, and a high-temperature blow water and high-pressure feed water heater system for the in-house boiler. A tank for receiving and cooling a high-temperature blow, and the cooled drain and / or steam is sent to a neutralization tank of a wastewater treatment facility.

  The blow tank 100 includes a tank main body 101, a cooling pipe 102 attached in the tank main body 101, and a cooling water supply means 103 that sends cooling water to the tank main body 101. The tank body 101 is provided with a temperature detector 104 and a temperature controller 105 for controlling the drain and / or steam to a predetermined temperature. Further, the tank body 101 is provided with a level detector 106 and a level controller 107 for controlling the water level to a predetermined level.

  Connected to the upper part of the tank main body 101 are a pipe line 83 communicating with the turbine flash pipe 47, a pipe line 72 communicating with the flash tank 53, a blow pipe 84 of the in-house boiler, and a blow pipe 85 of the high-pressure feed water heater system. Further, an exhaust pipe 108 for making the pressure in the tank main body 101 atmospheric pressure is provided at the upper part of the tank main body 101. On the other hand, a drain pipe 109 provided with a level adjustment valve 110 for sending water in the tank to the neutralization tank is provided at the bottom of the tank body 101.

  The cooling pipe 102 uses the condensate as a cooling medium, the condensate is sent from the outlet of the ground condenser 27, and the condensate whose temperature is increased through heat exchange with the drain and / or steam is returned to the inlet of the drain cooler 28. . A three-way valve 34 capable of adjusting the flow rate is attached in the middle of a pipe line 33 connecting the ground condenser 27 and the drain cooler 28. One outlet of the three-way valve 34 is connected to the inlet of the cooling pipe 102 through the pipe 35, and the outlet of the cooling pipe 102 is connected to the pipe 33 on the downstream side of the three-way valve 34 through the pipe 36. A shutoff valve 37 is provided in the middle of the pipeline 35.

  Since the condensate sent to the cooling pipe 102 is a cooling medium, it is preferable that the temperature is low. However, since the condensate is also used as a refrigerant for the cooler of the air extraction device 26, at least the condensate downstream of the air extraction device 26 It is preferable to send Moreover, it is preferable to return the condensate whose temperature has been increased by exchanging heat with drain and / or steam to a place where condensate having a temperature lower than its own temperature is circulating.

  The cooling water supply means 103 comprises a water supply pipe 113 provided with a shutoff valve 111 on the upstream side and a flow rate adjustment valve 112 on the downstream side in the middle of the pipeline, and sends industrial water to the tank body 101 for industrial use into drains and / or steam. Add water and cool.

  The shutoff valve 37 and the shutoff valve 111 are controlled by an operation control device (not shown) that controls the operation of the steam power plant. The three-way valve 34 and the flow rate adjustment valve 112 adjust the supply amount of condensate or industrial water so that the water temperature in the tank main body 101 becomes a set temperature according to a command from the temperature controller 105. The water level in the tank body 101 controls the level adjustment valve 109 so that the level controller 107 becomes a predetermined level.

  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 is provided to reduce the temperature so that steam exhausted from the bypass system 54 can be supplied to the condenser 21.

  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 32 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 blow pipe 72 having an adjustment valve 73 communicating with the blow tank 100.

  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 main steam stop valve 11 has an upper drain valve 81, and the upper drain valve 81 is connected to the turbine flush pipe 47 through the blow pipe 82.

  The temperature reducer 55 is a device for reducing the temperature of 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, and an adjustment provided at the outlet of the condensate booster pump 24. Condensate is supplied as water for temperature reduction through a temperature-reduced water supply pipe 77 having a valve 78, and the reduced-temperature steam is sent to the condenser 21 through a communication pipe 79.

  Next, an operation procedure at the time of starting the steam power plant and a method for treating drain and / or steam blown into the blow tank 100 at the time of startup 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. When the flash tank pressure exceeds 3.5 MPa, the dump steam valve 63 is opened, and surplus steam is sent to the condenser 21 via the temperature reducer 55.

  When the flash tank pressure becomes 0.98 MPa, the heater vent valve 60, the turbine bypass valve 75, and the upper drain valve 81 of the main steam stop valve 11 open, and the steam flows into the secondary superheater 7 and the main steam pipe 13 and this part. Is warmed. Warming of the main steam pipe 13 through the turbine bypass system 54 is continued until the flash tank pressure reaches about 3.5 MPa. On the other hand, the upper drain valve 81 of the main steam stop valve 11 is open until the valve switching is completed, during which steam is blown. The steam of the turbine bypass system 54 is sent from the turbine bypass pipe 76 to the temperature reducer 55, where it is reduced in temperature, and then condensed in the condenser 21. On the other hand, the blow steam from the upper drain valve 81 of the main steam stop valve 11 is sent to the turbine flash pipe 47, and the drain is further sent to the blow tank 100.

  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, it is no longer necessary to flow steam to the startup bypass system, so that the adjustment valve 57 of the primary superheater bypass system 51 is closed, the startup bypass operation is terminated, and the normal operation is started. Operation using the startup bypass system is also called low-load operation.

  During the startup bypass operation, auxiliary steam is supplied to the air extraction device 26 as working steam. On the other hand, in the ejector main steam system 40, the ejector main steam drain valve 44 opens when the main steam pressure reaches 3.3 MPa, just before the parallel, and the steam is blown from here to the turbine flash pipe 47, so that the ejector main steam system 40 Warming is performed. The warming of the ejector main steam system 40 is performed until the valve switching is completed.

  The blow tank 100 cools the hot drain and / or steam sent from the turbine flash pipe 47 in the following manner. When the startup bypass operation is started and the system water circulation through the condensate / feed water system becomes possible, the operation control device of the steam power plant opens the shut-off valve 37 to supply the condensate to the cooling pipe 102 and supplies industrial water. The shutoff valve 111 to be closed is closed. As a result, condensate, which is a cooling medium, can be supplied to the cooling pipe 102, and the three-way valve 34 sends the condensate to the cooling pipe 102 so that the water temperature of the tank body 101 becomes a predetermined temperature, for example, 60 ° C.

  During startup bypass operation, blow steam from the upper drain valve 81 of the main steam stop valve 11 and warming steam from the ejector main steam system 40 are sent to the turbine flash pipe 47 as described above, and further drain is sent to the blow tank 100. It is done. At the time when these drains are sent to the blow tank 100, the system water circulation operation through the condensate / water supply system is possible, so that these drains are cooled by the condensate via the cooling pipe 102. Since the cooling of the drain by the cooling pipe 102 is indirect cooling, the waste water sent to the neutralization tank does not increase more than the drain amount, and the load of the waste water treatment can be reduced as compared with the cooling method of the direct contact method. In addition, since the condensate that has cooled the drain is returned to the condensate system, the load on the feed water heater is reduced.

  In the blow tank 100, high-temperature drain and / or steam is discarded other than during the startup bypass operation. For example, before starting the steam power plant, an in-house boiler (not shown) is started in order to secure auxiliary steam to be used when starting the steam power plant. Since the blow steam of the in-house boiler is sent to the blow tank 100, high-temperature drain and / or steam is sent to the blow tank 100 even before the start of the steam power plant. Since condensate cannot be supplied to the cooling pipe 102 at this time, the operation control device of the steam power plant opens the shut-off valve 111, closes the shut-off valve 37, and tanks industrial water through the cooling water supply means 103. Supply to the main body 101. The flow rate adjusting valve 112 sends industrial water to the tank body 101 so that the water temperature of the tank body 101 becomes a predetermined temperature, for example, 60 ° C.

  In a conventional steam power plant, all the high-temperature drain and / or steam that is discarded in the blow tank 100 is cooled by adding industrial water to the neutralization tank of the wastewater treatment facility after being cooled. There was a lot of expense for industrial water for the wastewater treatment, and also for the wastewater treatment after cooling. In contrast, in the steam power plant shown in the present embodiment, the high-temperature drain and / or steam that is discarded in the blow tank 100 during the start-up bypass operation is cooled via the cooling pipe 102, so that excess drainage is generated. The processing cost is also unnecessary. Further, since heat can be recovered from the high-temperature drain and / or steam that is discarded, the thermal efficiency is increased. In the present embodiment, the industrial water can be sent from the cooling water supply means 103 even during the start-up bypass operation, and the drain and / or steam discarded in the blow tank 100 can be cooled. The cooling pipe 102 is preferentially used for the water supply means 103. Since the two cooling means having different cooling media are provided, the blow tank can be operated efficiently.

  The steam blow to the turbine flush pipe 47 during the startup bypass operation may take 5 to 6 hours, so that a large amount of drain and / or steam is discarded in the blow tank during the startup bypass operation. The blow tank 100 provided is preferable. Furthermore, in a steam power generation 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 is sent to the blow tank 100 via the turbine flash pipe 47. Since the amount of drain and / or steam increases, it is effective to provide the blow tank 100 of the present invention for such a steam power plant. Further, since the blow tank 100 of the present invention has a simple configuration, it can be easily applied to existing steam power plants by performing simple modifications.

  The present invention is not limited to the above-described embodiment, and can be changed to various embodiments and used without departing from the spirit of the invention. For example, instead of the cooling water supply means 103, a jacket or a cooling pipe may be provided around the inside of the tank body 101, and industrial water or seawater may be supplied thereto to cool the drain and / or steam. Since this method is also indirect cooling like the cooling pipe 102, supplied industrial water or seawater does not become drainage. Further, instead of providing the cooling pipe 102 in the tank main body 101, a jacket or a cooling pipe may be provided around the tank main body 101 to supply condensate as a cooling medium. From the viewpoint of heat transfer performance, it is preferable to provide the cooling pipe 102 in the tank body 101. Further, condensate may be sent from the outlet of the air extraction device 26 to the cooling pipe 102, and the condensate that has exchanged heat with the drain and / or steam may be returned to the inlet of the ground condenser 26. Moreover, you may employ | adopt another method also for the control method of the water temperature of the blow tank 100, and the control method of a water level. In the above embodiment, the drain and / or steam discarded in the blow tank 100 is specifically shown. However, the drain and / or steam discarded in the blow tank 100 is the above-described drain and / or steam. Needless to say, it may be other than the above.

DESCRIPTION OF SYMBOLS 1 Boiler 21 Condenser 22 Condensate pump 26 Air extraction device 27 Grand condenser 28 Drain cooler 29 Low pressure feed water heater 34 Three-way valve 35 Pipe line 36 Pipe line 37 Shut-off valve 45 Blow pipe 47 Turbine flush pipe 51 Primary superheater bypass system 52 Secondary superheater bypass system 53 Flash tank 54 Turbine bypass system 55 Temperature reducer 63 Dump steam valve 64 Dump steam delivery pipe 81 Upper drain valve 82 Blow pipe 83 Line 84 In-house boiler blow pipe 85 High-pressure feed water heater system Blow pipe 100 Blow tank 101 Tank body 102 Cooling pipe 103 Cooling water supply means 104 Temperature detector 105 Temperature controller 106 Level detector 107 Level detector 108 Exhaust pipe 109 Drain pipe 110 Level adjustment valve 111 Shut-off valve 112 Flow adjustment valve 113 Water pipe

Claims (6)

A blow tank provided in a steam power plant for receiving drain and / or steam, cooling it and sending it to a wastewater treatment device,
The tank body,
An indirect cooling means for cooling the drain and / or steam provided in the tank body and using condensate as a cooling medium;
A blow tank characterized by comprising:   2. The blow tank according to claim 1, further comprising second cooling means that is provided in the tank body and cools drainage and / or steam and uses industrial water or seawater as a cooling medium. A method of using the blow tank according to claim 1 or 2,
The steam power plant includes at least a condenser that cools and condenses exhaust steam from a steam turbine, a condensate pump that feeds condensate, an air extraction device that evacuates the condenser with a steam ejector, a ground A ground condenser that exchanges heat between steam and condensate, a drain cooler that is located upstream of the low-pressure feed water heater and exchanges heat between the drain and condensate, and these flow from the condenser toward the low-pressure feed water heater. Having a condensate system arranged in the above order,
Condensate is sent from the outlet of the air extraction device to the indirect cooling means, and the condensate heat-exchanged with the drain and / or steam is returned to the inlet of the ground condenser,
Alternatively, the method of using a blow tank is characterized in that condensate is sent from the outlet of the ground condenser to the indirect cooling means, and the condensate heat-exchanged with the drain and / or steam is returned to the inlet of the drain cooler. A method of using the blow tank according to claim 2,
The drain and / or steam is drain and / or steam blown before and during startup of the steam power plant,
The indirect cooling means is used in preference to the second cooling means, and when the condensate cannot be supplied to the indirect cooling means, the second cooling means is used to cool the drain and / or steam. How to use the featured blow tank. After the boiler is started, the steam power plant distributes water and / or steam until a predetermined steam is supplied to the steam turbine and is switched to normal load operation, and exhausted steam and / or drain is passed through a temperature reducer. Comprising a start-up bypass device for sending to the condenser and condensing,
5. The blow according to claim 4, wherein the drain and / or steam blown at startup of the steam power plant is drain and / or steam blown at startup bypass operation using the startup bypass device. How to use the tank.   The method of using a blow tank according to any one of claims 3 to 5, wherein the steam power plant is a steam power plant that supports weekend start / stop (WSS) operation or midnight start / stop (DSS) operation. .

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