JP2012184742A - Exhaust path formation method for steam and drain in drying operation of reheater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust path formation method for reducing an exhaust time by efficiently exhausting steam generated by the evaporation of water pressure test water remaining inside a reheater and a drain outward, and simplifying formation of an exhaust path.SOLUTION: A power generation plant has a secondary steam flowage path B through which primary steam from a high pressure turbine supplied to the reheater 12 and reheated in the reheater is sent to an intermediate pressure turbine 3. The secondary steam flowage path B includes: a drain-exhausting on-off valve 17 that is an electric valve present in a path of a drain exhaust pipe 16 branched from a low temperature reheating steam pipe 13; and drain-exhausting on-off valves 45, 46 that are electric valves present in paths of drain exhaust pipes 43, 44 branched from a high temperature reheating steam pipes 14. The drain-exhausting on-off valves are fully opened before a drying operation, and the steam generated by the evaporation of the water remaining inside the reheater and the drain obtained by condensation of the steam are exhausted outside the secondary steam flowage path B from the drain exhaust pipes, in the drying operation.

Description

  The present invention relates to a reheater provided in a boiler of a power generation facility such as a thermal power plant, in performing a drying operation for evaporating water remaining in the reheater after a water pressure test. The present invention relates to a method for forming a path for discharging drain condensed by the steam to the outside.

  Power generation equipment such as a thermal power plant equipped with this kind of steam supply equipment includes a boiler that generates steam by burning fuel, a steam turbine that is supplied with steam from the boiler, and driven through the steam turbine. And at least a condenser that cools the steam supplied to the steam turbine, and the boiler introduces condensate from the condenser to generate primary steam, and the primary steam is generated by the steam turbine. A superheater that supplies the high pressure turbine of the steam turbine, a reheater that introduces primary steam from the high pressure turbine of the steam turbine and reheats to generate secondary steam, and supplies the secondary steam to the intermediate pressure turbine of the steam turbine; For example, a configuration having a power generator is already known as a power generation device disclosed in Patent Document 1.

  In addition, after the boiler water pressure test, when the boiler is ignited for the start-up of the power equipment, after the boiler water pressure test, the water remaining in the reheater is prevented from occurring due to water remaining in the reheater. A method of performing a drying operation in which the water inside the reheater is discharged and the boiler is ignited to dry the inside of the reheater and the water remaining inside the reheater is evaporated is disclosed in Patent Document 2, for example. As already known.

  Furthermore, when forming a path for discharging the water remaining in the reheater from the secondary steam flow path having the reheater as a component to the steam formed by evaporating the water remaining in the reheater or the condensed drain of the steam, the above-mentioned patent In Reference 2, during the drying operation, the drain valve of the low-temperature reheat steam pipe is closed, the drain valve provided in the high-temperature reheat steam pipe is opened, and the steam generated in the reheater is flowed into the secondary steam. A method of forming a discharge path out of the path is also shown.

JP 2008-292119 A JP 2008-116162 A

  However, as shown in Patent Document 2, it is necessary to close the drain valve of the low-temperature reheat steam pipe, open the drain valve provided in the high-temperature reheat steam pipe, and discharge the steam inside the reheater. Since the flow path area for discharging the drain is relatively small, it is considered that the discharge of steam and drain becomes insufficient, or the time for discharging the steam and drain becomes long.

  Further, as shown in FIG. 5, the drainage valve 203 provided in the drainage pipe 204 for discharging the water from the reheater 201 to the blow tank 202 after the water pressure test is fully opened during the drying operation. There is also a method of discharging steam and drain from the pipe 204 to the outside of the secondary steam flow path 205. However, since the drain valve 203 is a manual valve, the drain valve 203 is operated by an operator going to the site and turning the valve handle. Therefore, the operation for forming the discharge path for the steam and drain during the drying operation of the reheater becomes complicated.

  Therefore, the present invention uses other automated discharge means disposed in the secondary steam flow path to remove the steam formed by evaporating water remaining in the reheater and the drain condensed by the steam. It is possible to discharge out of the secondary steam flow path, improve steam and drain discharge, shorten the steam and drain discharge time, and easily form the steam and drain discharge path. It is an object of the present invention to provide a method for forming a steam and drain discharge path during a drying operation of a possible reheater.

  A steam and drain discharge path forming method for drying operation of a reheater according to the present invention includes a boiler that generates steam by burning fuel, a steam turbine to which steam is supplied from the boiler, and the steam turbine. A generator driven through the condenser and a condenser for cooling the steam supplied to the steam turbine, the boiler introduces condensate from the condenser to generate primary steam, and A superheater that supplies primary steam to the primary turbine of the steam turbine, and introduces the primary steam from the primary turbine and reheats to generate secondary steam, and the secondary steam is secondary to the steam turbine. In a power generation facility having a reheater for supplying to a turbine, a secondary steam flow path is configured by connecting the primary turbine, the reheater and the secondary turbine with a steam pipe. The first drain discharge pipe and the drain for discharging the drain generated in the steam pipe to the upstream side of the flow of the secondary steam from the reheater of the steam flow path to the outside of the secondary steam flow path A first drain discharge on-off valve for opening and closing the discharge pipe is disposed, and is generated in the steam pipe on the downstream side of the flow of the secondary steam from the reheater of the secondary steam flow path. A second drain discharge pipe for discharging the drain out of the secondary steam flow path and a second drain discharge on-off valve for opening and closing the drain discharge pipe are arranged, and liquid is injected into the boiler After the test, the liquid inside the reheater is discharged, and before performing the drying operation of the reheater for igniting the boiler and drying the reheater, Drain discharge on-off valve and the second drain discharge on-off valve Both are opened and the vapor generated by evaporation of the liquid remaining in the reheater by the drying operation of the reheater and the drain condensed by the vapor are caused to flow into the secondary steam pipe. The steam can be discharged out of the secondary steam flow path from both the first and second drain discharge pipes (Claim 1). Here, the power generation facility is, for example, a thermal power plant. The primary turbine is, for example, a high-pressure turbine, and the secondary turbine is, for example, an intermediate-pressure turbine. The test performed by injecting liquid into the boiler is, for example, a water pressure test for inspecting the presence or absence of water leakage from components such as a reheater constituting the boiler. The liquid used in the water pressure test is, for example, water. . The first and second drain discharge pipes are connected to, for example, a condenser of the power generation facility.

  As a result, the liquid such as water remaining in the reheater is evaporated after the test conducted by injecting the liquid into the boiler by the drying operation of the reheater, and the vaporized vapor of this liquid and the condensed drain of this vapor are Since it can be discharged out of the secondary steam flow path during the drying operation, the basic problem of eliminating the water hammer caused by the liquid remaining in the reheater at the start-up of the power generation equipment Aim can be achieved.

  Further, in the secondary steam flow path, a first drain discharge on-off valve located on the upstream side of the secondary steam flow from the reheater and a second located on the downstream side of the secondary steam flow from the reheater. Since both of the drain discharge on-off valve of the boiler are fully opened, the vapor formed by evaporating the liquid remaining in the reheater after the test conducted by injecting the liquid into the boiler, and the drain condensed with the vapor, It becomes possible to discharge out of the secondary steam flow path from both the drain discharge pipe and the second drain discharge pipe.

  In the method for forming a steam and drain discharge path during the drying operation of the reheater according to the present invention, the first drain discharge on-off valve and the second drain discharge on-off valve are automatically controlled. (Claim 2).

  Thus, the first and second drain discharge on / off valves for discharging the vapor obtained by evaporating the liquid remaining in the reheater from the first and second drain discharge pipes are opened and closed by automatic control. This eliminates the need for the operator to go to the site to open the on-off valve.

  Further, in the method for forming a steam and drain discharge path during the drying operation of the reheater according to the present invention, the secondary steam flow path is a liquid discharge system or the like for draining the liquid in the reheater. A predetermined system for purposes other than drainage is provided, and an on-off valve is provided on the upstream side of the piping path constituting the predetermined system, and the on-off valve is closed during the drying operation of the reheater. (Claim 3).

  Thereby, the steam generated in the drying operation of the reheater and the drain condensed with this steam are other than the first and second drain discharge pipes, such as a liquid discharge system for draining the liquid in the reheater. It does not flow into a given system.

  Furthermore, in the method for forming a discharge path for steam and drain during the drying operation of the reheater according to the present invention, the secondary steam flow path is more than the portion where the first drain discharge pipe is provided. Regulating means for regulating the flow of steam and drain in the secondary steam flow path is provided on the secondary turbine side rather than on the primary turbine side and the portion where the second drain discharge pipe is provided, The regulating means regulates the flow of steam and drain in the secondary steam flow path during the drying operation of the reheater (Claim 4). Here, the restricting means is, for example, a closed portion on the low temperature reheat steam pipe side, and is, for example, a reheat steam stop valve on the high temperature reheat steam pipe side.

  Thereby, the steam generated in the drying operation of the reheater or the drain condensed with this steam does not inadvertently flow into the primary turbine or the secondary turbine.

  As described above, according to the present invention, the liquid such as water remaining in the reheater after the test performed by injecting the liquid into the boiler by the drying operation of the reheater is evaporated, This steam condensed drain can be discharged out of the secondary steam flow path during the drying operation, which is caused by the liquid remaining in the reheater when the boiler is ignited to start the power generation equipment. It is possible to prevent the water hammer from occurring.

  Further, according to the present invention, the first drain discharge on-off valve located on the upstream side of the secondary steam flow from the reheater in the secondary steam flow path and the downstream of the secondary steam flow from the reheater. Both the second drain discharge on-off valve located on the side is fully opened, and the vapor formed by evaporating the liquid remaining in the reheater and the drain condensed by the vapor are supplied to the first drain discharge pipe and the second drain discharge pipe. Since it is possible to discharge from both the drain discharge pipe and the secondary steam flow path, it is possible to efficiently discharge the steam and drain, and the time for discharging the steam and drain to the outside. Can be shortened.

  Furthermore, according to the present invention, the first and second drain discharge pipes and the drain first and second drain discharge on-off valves are already installed in the power generation facility and do not need to be newly provided. This method can also be used in a power generation facility, and there is no increase in cost due to the expansion of the facility.

  In particular, according to the second aspect of the present invention, the first vapor for discharging the vapor formed by evaporating the liquid remaining in the reheater and the drain condensed by the vapor from the first and second drain discharge pipes. And the second drain discharge on-off valve can be opened and closed by automatic control, so there is no need for an operator to go to the site to open the on-off valve, and steam during the drying operation of the reheater. It is possible to simplify the work for environmental maintenance before the drying operation of the reheater to form the discharge path.

  In particular, according to the third aspect of the present invention, the steam in the reheater, in which the steam generated in the drying operation of the reheater and the drain condensed by this steam are other than the first and second drain discharge pipes. It is possible to prevent inflow into other systems other than drain discharge such as a liquid discharge system for removing water.

  In particular, according to the invention described in claim 4, it is possible to prevent inadvertent inflow of steam generated in the drying operation of the reheater or drain condensed from the steam into the primary turbine and the secondary turbine. it can.

FIG. 1 is a schematic diagram showing an arrangement configuration of a reheater or the like of a power facility. FIG. 2 is an explanatory diagram showing the configuration of the secondary steam flow path of the power equipment and the steam and drain discharge path during the drying operation of the reheater of the present invention. Figure 3 shows the process of performing a hot cleanup / safety valve test of the reheater after draining from the reheater, preparing the reheater drying environment, and reheating the reheater after the boiler water pressure test. It is a flowchart which shows. FIG. 4 is a characteristic diagram showing the temperature management state in the drying operation of the reheater, the hot cleanup of the reheater, and the safety valve test. FIG. 5 is an explanatory diagram showing a steam and drain discharge path during the drying operation of the reheater other than the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1, a schematic diagram of a power generation facility 1 is shown. The power generation facility 1 includes a boiler 2 that burns fuel to generate steam, a high-pressure turbine 3, an intermediate-pressure turbine 4, and a low-pressure turbine 5 that are steam turbines to which steam is supplied from the boiler 2, and these high-pressure turbines. 3. It has at least a generator 6 driven via the intermediate pressure turbine 4 and the low pressure turbine 5, and a condenser 7 for cooling the steam supplied to the high pressure turbine 3, the intermediate pressure turbine 4 and the low pressure turbine 5. It consists of In this embodiment, the high-pressure turbine 3, the intermediate-pressure turbine 4, the low-pressure turbine 5, and the generator 6 are the same in the order of the generator 6, the high-pressure turbine 3, the intermediate-pressure turbine 4, and the low-pressure turbine 5. It is connected on the shaft. However, the connection order of the turbines 3, 4, 5 and the generator 6 is not limited to the illustrated configuration, and the generator 6 may be connected on the low-pressure turbine 5 side, for example.

  The boiler 2 includes a steam pipe 10 that introduces condensate from the condenser 7 and generates primary steam by heating, and a superheater 11 that superheats the primary steam into high-temperature and high-pressure steam and supplies the steam to the high-pressure turbine 3. And a reheater 12 that generates secondary steam (reheated steam) by introducing primary steam from the high-pressure turbine 3 and reheating it, and supplies the secondary steam to the intermediate pressure turbine 4. .

  In this embodiment, the superheater 11 is, as shown in FIG. 1, a primary superheater 11 a located close to the downstream side of the steam pipe 10, and a form away from the primary superheater 11 a with respect to the steam pipe 10. And the secondary superheater 11b located on the downstream side of the steam pipe 10. As shown in FIG. 2, the reheater 12 is formed to be folded back in a meandering manner with the tube nests 12 a and 12 b and is arranged between the tube nests 12 a and 12 b and connected to the tube nests 12 a and 12 b. And a reheater tube 12c.

  With this configuration, the power generation facility 1 includes a primary steam flow path A from the condenser 7 to the high pressure turbine 3 via the steam pipe 10 of the boiler 2, the primary superheater 11 a, the secondary superheater 11 b, and the high pressure turbine 3. A secondary steam flow path B that reaches the intermediate pressure turbine 4 through the reheater 12 of the boiler 2 and a steam constant flow path C that passes from the intermediate pressure turbine 4 through the low pressure turbine 5 to the condenser 7. It is also.

  Next, the secondary steam flow path B will be described in detail below with reference to FIG. The secondary steam flow path B includes a low-temperature reheat steam pipe 13 that connects the high-pressure turbine 3 and the inlet side of the reheater 12, and a high-temperature regenerator that connects the outlet side of the reheater 12 and the intermediate pressure turbine 4. And a steam vapor pipe 14 so that steam flows in the direction of the solid arrow in FIG.

  As shown in FIG. 2, the low-temperature reheat steam pipe 13 includes a closed portion 15 that blocks the flow of steam through the low-temperature reheat steam pipe 13, and is closer to the reheater 12 than the closed portion 15. The drain discharge pipe 16 is branched. The drain discharge pipe 16 is for discharging drain generated in the low-temperature reheat steam pipe 13 to the outside of the secondary steam flow path B, and is connected to the condenser 7 in this embodiment. The drain discharge pipe 16 includes at least a drain discharge on-off valve 17 for opening and closing the drain discharge pipe 16 and a storage unit 18 for temporarily inserting the high-temperature and high-pressure steam before sending it to the condenser 7. Is provided. The drain discharge on-off valve 17 is an electric valve that automatically opens and closes the drain discharge pipe 16 by a motor 17a.

  Further, the low-temperature reheat steam pipe 13 supplies heating steam to a predetermined feed water heater (for example, a seventh feed water heater) (not shown) on the downstream side of the secondary steam from the branch portion of the drain discharge pipe 16. The heating steam supply system 19, the auxiliary steam supply system 20 for supplying the auxiliary steam to the high-pressure turbine 3 to warm the high-pressure turbine 3 when the power generation facility 1 is started, the temperature reducer 21, A reheat steam temperature lowering system 22 for injecting water into the reheater 12 to lower the temperature in the reheater 12 when the reheat steam temperature rises due to pipe connection with the temperature reducer 21, Have. The heating steam supply system 19, auxiliary steam supply system 20, and reheat steam temperature lowering system 22 have on-off valves 23, 24, 25, and 26 on the upstream side of the pipes constituting each system.

The reheater 12 includes a water injection system 29 for filling the reheater 12 with water from the flash tank 28 during the safety valve test, and a drainage system for discharging water in the reheater 12 to the blow tank 30 after the water pressure test. 31 is connected to the steam inlet side, and on-off valves 32 and 33 are provided on the piping path constituting the water injection system 29, and the on-off valve 34 is provided on the piping path constituting the drainage system 31. Is provided. At least the on-off valve 34 is a manual valve that opens and closes by turning the valve handle. The reheater 12 has an air vent system 35 for extracting air from the reheater 12 on the outlet side of the steam. The air vent system 35 has a primary on-off valve 36 and a secondary on-off on the path. A valve 37 is provided. The air venting system 35 is connected with a nitrogen sealing system 38 for sealing nitrogen gas (N ₂ ) on the outlet side of the reheater 12 between the primary switching valve 36 and the secondary switching valve 37. The nitrogen-filled system 38 is provided with an open / close valve 39 on its path.

  In this embodiment, the high-temperature reheat steam pipe 14 is divided into a first high-temperature reheat steam pipe 14 a and a second high-temperature reheat steam pipe 14 b on the downstream side of the air vent system 35 and the nitrogen-filled system 38. The first high-temperature reheat steam pipe 14a and the second high-temperature reheat steam pipe 14b are connected to the intermediate pressure turbine 4, respectively. The first high-temperature reheat steam pipe 14a and the second high-temperature reheat steam pipe 14b are provided with reheat steam stop valves 41 and 42 on their paths, respectively.

  Further, drain discharge pipes 43 and 44 are branched from the middle of the first high-temperature reheat steam pipe 14a and the second high-temperature reheat steam pipe 14b, respectively. The drain discharge pipes 43 and 44 are for discharging the drain generated in the high-temperature reheat steam pipe 14 to the outside of the secondary steam flow path B, and are connected to the condenser 7 in this embodiment. The drain discharge pipe 43 includes at least a drain discharge on-off valve 45 for opening and closing the drain discharge pipe 43 and a storage section 47 for temporarily inserting the high-temperature and high-pressure steam before sending it to the condenser 7. The drain discharge pipe 44 includes at least a drain discharge on-off valve 46 for opening and closing the drain discharge pipe 44 and a storage portion 47 for temporarily inserting high-temperature and high-pressure steam before being sent to the condenser 7. Is provided. The drain discharge on-off valves 45 and 46 are motor-operated valves that automatically open and close the drain discharge pipe 43 or the drain discharge pipe 44 by motors 45a and 46a, respectively.

  By the way, while the boiler 2 of the power generation facility 1 needs to perform a water pressure test based on laws and regulations in order to check the presence or absence of water leakage and the pressure resistance, water remains in the reheater 12 constituting the boiler 2. In such a case, a water hammer may be generated when the power generation facility 1 is started (when the boiler 2 is ignited). Along with this, an outline of the process for the reheater 12 performed after the water pressure test for preventing the occurrence of this water hammer will be described using the flowchart shown from the start step 100 to the end step 106 in FIG. A description of the characteristic diagram of FIG. 4 will be added and described below.

  First, in Step 101 after the water pressure test, the water for water pressure test in the reheater 12 is discharged. For drainage from the reheater 12, the operator manually opens the on-off valve 34 shown in FIG. 2 at the site, and sends water for water pressure test from the reheater 12 to the blow tank 30 through the drainage system 31. Is done. Furthermore, in this embodiment, the on-off valves 36 and 39 are opened and nitrogen gas is sealed in the reheater 12 from the outlet side of the reheater 12, so that the inside of the reheater 12 is also pressurized by nitrogen gas. An operation of discharging water from the drain pipe 31 is performed.

  Next, in step 102, the environment of the drying operation of the reheater 12 is improved. In the maintenance of the drying operation of the reheater 12, the water remaining in the reheater 12 after the drainage in Step 101 becomes steam in the drying operation, and further, the steam is condensed and drained. In this case, an operation for forming a path for discharging the steam and drain out of the secondary steam flow path B and confirming a path for discharging the steam and drain (discharge of steam and drain before the reheater drying operation) Route formation / confirmation) and work for preparing the reheater 12 for drying operation (preparation for reheater drying operation). The pre-reheater drying operation steam and drain discharge path formation / confirmation, and the reheater drying operation preparation are performed according to the specified operation manual, thereby clarifying the operation details and preventing misoperation. It is planned to do. In this operation, for example, in the formation and confirmation of the steam and drain discharge path before the reheater drying operation, the on-off valves 23, 24, 25, 26, 33, and 36 are fully closed and the fully closed state is confirmed. Further, in order to prevent inadvertent driving due to the steam inflow of the high-pressure turbine 3 and the intermediate-pressure turbine 4 and to prevent the drain from entering the high-pressure turbine 3 and the intermediate-pressure turbine 4, the closing portion 15 is closed and the When the thermal steam stop valves 41 and 42 are closed, the closed portion 15 is closed, the reheat steam stop valves 41 and 42 are fully closed, and the closed / fully closed state is also confirmed. The opening and closing of the on-off valve that forms the steam discharge path and the confirmation of the fully open state are also performed during the formation and confirmation of the steam and drain discharge path before the reheater drying operation. The on-off valve that is fully opened will be described later. .

  Further, in step 103, the reheater 12 is dried (the reheater is dried in FIG. 4). The drying operation of the reheater 12 is started by igniting the boiler 2 as shown in FIG. 4, and the drying operation of the reheater 12 is performed, for example, for about 8 hours. During the drying operation of the reheater 12, the steam temperature at the inlet of the primary superheater 11a is monitored by the temperature sensor 49 disposed on the inlet side of the primary superheater 11a as shown in FIG. As shown, the combustion control of the boiler 2 is controlled so that the steam temperature at the inlet of the primary superheater 11a does not exceed 190 ° C.

Further, as shown in FIG. 1, a pressure sensor 50 for measuring the reheat steam pressure inside the reheater 12 is disposed on the secondary steam flow path B, and the reheater 12 since the temperature sensor 51 for measuring the metal temperature T _M of the outlet side is disposed on the outlet side of the reheater 12, the drying reheater during operation 12 inside the reheat steam pressure and reheaters 12 of the metal temperature T _M of the outlet side was measured by using the resulting reheat steam pressure value and metal temperature T _M, continuous or the end of the drying operation of the reheater 12 is determined.

That is, based on the saturation temperature table shown in Table 1, the saturation temperature T ₀ corresponding to the reheat steam pressure value obtained from the measurement result is calculated, and this saturation temperature value T ₀ and the measured metal temperature T are calculated. and performs drying operation reheater 12 while comparing the _M, again in the case of metal temperature T _M is determined to be lower than the end of the drying temperature plus temperature T _a determined in advance to the saturation temperature T ₀ determined continuation of the drying operation of the heat sink 12, the drying operation of the reheater 12 when determining that the metal temperature T _M becomes predetermined temperature T _a drying finish temperature greater than or equal to the added to the saturation temperature T ₀ The end of is determined. Incidentally, the temperature T _a can be arbitrarily determined, it can be determined, for example, from 10 ° C. to 20 ° C..

  After the drying operation of the reheater 12 is completed, the process proceeds to step 104 to perform hot cleanup of the reheater 12 (hot cleanup in FIG. 4). As shown in FIG. 4, the transition from the end of the drying operation to the hot clean-up is performed when the reheater 12 is in the drying operation by additionally igniting a burner (not shown) of the boiler 2 (for example, the third and fourth cell burners) This is done by raising the temperature. This hot cleanup is performed, for example, for about 3 hours. Further, during this hot cleanup period, the temperature of the steam at the inlet of the primary superheater 11a is monitored by the temperature sensor 49 so that the steam temperature at the inlet of the primary superheater 11a does not exceed 275 ° C. Is controlled.

  Further, after the hot cleanup is completed, the routine proceeds to step 105 where warming of the reheater 12 and a safety valve test (reheater warming / safety valve test of FIG. 4) are performed. The transition from hot cleanup to reheater warming / safety valve test is also performed by raising the temperature of the hot cleanup. During the reheater warming / safety valve test, the temperature sensor 49 monitors the steam temperature at the inlet of the primary superheater 11a so that the steam temperature at the inlet of the primary superheater 11a does not exceed 369 ° C. Control of combustion of the boiler 2 is performed.

  And, by making the drying operation of these reheaters, hot cleanup and reheater warming / safety valve tests also in accordance with the prescribed operation manual, the operation details etc. are clarified and erroneous operations are prevented. Is planned.

  Here, the on-off valve that is fully opened before the reheating operation of the reheater 12 in order to form a discharge path for steam and drain before the reheater drying operation and whose fully opened state is confirmed is shown in FIG. Thus, the drain discharge on-off valve 17 existing on the low-temperature reheat steam pipe 13 side and the drain discharge on-off valves 45, 46 existing on the high-temperature reheat steam pipe 14 side. The low-temperature reheat steam pipe 13 that connects the reheater 12 and the high-pressure turbine 3 is in a state of being closed by the closing portion 15 in this embodiment, and connects the reheater 12 and the intermediate pressure turbine 4. In this embodiment, the reheat steam stop valves 42 and 43 of the high temperature reheat steam pipes 14a and 14b among the high temperature reheat steam pipes 14 are fully closed. As shown in FIG. 2, there is an open / close valve 53 on the low-temperature reheat steam pipe 13 side of the drain discharge pipe 16 than the drain discharge open / close valve 17, and more than the drain discharge open / close valve 45 of the drain discharge pipe 43. When there is an on-off valve 54 on the high-temperature reheat steam pipe 14 side, and there is an on-off valve 55 on the high-temperature reheat steam pipe 14 side than the drain discharge on-off valve 46 of the drain discharge pipe 44, these on-off valves 53 , 54 and 55 are also fully opened.

  As a result, the water remaining in the reheater 12 evaporates into a vapor during the drying operation of the reheater 12, and the steam generated during the drying operation of the reheater 12 (the drain condensed with this vapor). As shown by the broken arrow, one side of the other is also in the same direction as the secondary steam flows (solid arrow) from the outlet side of the reheater 12 through the high temperature reheat steam pipe 14 and the high temperature reheat steam pipe 14. Steam (14a and 14b) is sent to the condenser 7 through drain discharge pipes 43 and 44 branched from the high-temperature reheat steam pipes 14a and 14b, and steam generated in the drying operation of the reheater 12 ( The other side of the steam also includes condensate). As indicated by the dashed arrow, the low-temperature reheat from the inlet side of the reheater 12 is opposite to the direction in which the secondary steam flows (solid arrow). Branched from the low-temperature reheat steam pipe 13 through the steam pipe 13 Sent to the condenser 7 via the lens discharge pipe 16.

  Therefore, the steam generated in the drying operation and the drain condensed by the steam are secondary steam from the drain discharge pipes 43 and 44 branched from the high-temperature reheat steam pipe 14 and the drain discharge pipe 16 branched from the low-temperature reheat steam pipe 13. Since it is discharged out of the flow path B, the steam and drain are discharged more efficiently than the case where the steam and drain are discharged only from the high-temperature reheat steam pipe 14. Further, since the drain discharge on-off valves 17, 45, and 46 are all electrically operated valves, there is no need for the operator to go to the site and open the on-off valves.

1 Power generation equipment 2 Boiler 3 High-pressure turbine (steam turbine: primary turbine)
4 Medium-pressure turbine (steam turbine: secondary turbine)
5 Low pressure turbine (steam turbine)
6 Generator 7 Condenser 11 Superheater 11a Primary superheater 11b Secondary superheater 12 Reheater 13 Low-temperature reheat steam pipe 14 (14a, 14b) High-temperature reheat steam pipe 16, 43, 44 Drain discharge pipe 17, 45, 46 Drain discharge open / close valves 17a, 45a, 46a Motor 19 Heating steam supply system 20 Auxiliary steam supply system 22 Reheat steam temperature lowering system 23, 24, 25, 26, 32, 34, 36, 39 Open / close valve 29 Water injection system 31 Drainage system
35 Air venting system 38 Nitrogen-filled systems 41, 42 Reheat steam stop valve A Primary steam flow path B Secondary steam flow path C Steam flow path

Claims (4)

A boiler that generates steam by burning fuel, a steam turbine that is supplied with steam from the boiler, a generator that is driven through the steam turbine, and a condensate that cools the steam supplied to the steam turbine And the boiler introduces condensate from the condenser to generate primary steam, supplies the primary steam to the primary turbine of the steam turbine, and the primary steam to the primary steam. In a power generation facility having a reheater for generating secondary steam by introducing from a turbine and reheating, and supplying the secondary steam to the secondary turbine of the steam turbine,
The primary turbine, the reheater, and the secondary turbine are connected by a steam pipe to form a secondary steam flow path, and the secondary steam flow is upstream of the reheater in the secondary steam flow path. A first drain discharge pipe for discharging drain generated in the steam pipe to the outside of the secondary steam flow path and a first drain discharge on-off valve for opening and closing the drain discharge pipe. And a second for discharging the drain generated in the steam pipe to the downstream side of the flow of the secondary steam from the reheater of the secondary steam flow path to the outside of the secondary steam flow path. A drain discharge pipe and a second drain discharge on-off valve for opening and closing the drain discharge pipe,
After the test conducted by injecting the liquid into the boiler, the liquid inside the reheater is discharged, and before the reheater drying operation for igniting the boiler and drying the reheater inside is performed. In addition, both the first drain discharge on-off valve and the second drain discharge on-off valve are opened, and the liquid remaining in the reheater evaporates by the drying operation of the reheater. The generated steam and the condensed drain of the steam are caused to flow into the secondary steam pipe, so that the steam is discharged out of the secondary steam flow path from both the first and second drain discharge pipes. A method for forming a discharge path for steam and drain during the drying operation of the reheater, characterized in that   The steam and drain during the drying operation of the reheater according to claim 1, wherein the first drain discharge on-off valve and the second drain discharge on-off valve are opened and closed by automatic control. Discharge route formation method. The secondary steam flow path is provided with a predetermined system for purposes other than drain discharge, such as a liquid discharge system for draining the liquid in the reheater, and is a path of piping constituting these predetermined systems. An on-off valve is provided upstream,
The method for forming a discharge path for steam and drain during the drying operation of the reheater according to claim 1 or 2, wherein the on-off valve is closed during the drying operation of the reheater. . The secondary steam flow path includes the primary turbine side from the portion where the first drain discharge pipe is provided and the secondary turbine side from the portion where the second drain discharge pipe is provided. A regulation means is provided to regulate the flow of steam and drain in the secondary steam flow path,
The said restriction | limiting means regulates the flow of the vapor | steam and drain in the said secondary vapor | steam flow path | route at the time of the drying operation of the said reheater, The recycle in any one of Claim 1, 2, or 3 characterized by the above-mentioned. A method for forming a discharge path for steam and drain during drying operation of a heater.

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