Auxiliary steam generator and combined power plant

Abstract

The present disclosure relates to an auxiliary steam generating device for producing auxiliary steam for a steam load of a combined cycle power plant, which can use steam generated by utilizing waste heat from a gas turbine to drive a steam turbine. The auxiliary steam generating device produces steam by heating pressurized water from a water supply pump located downstream of a steam drum, using a pressurized water heating unit, and then flash-evaporating the heated pressurized water. The auxiliary steam is produced by superheating the generated steam using a steam superheating unit.

Description

Technical field

[0001] The present disclosure relates to an auxiliary steam generating device and a combined cycle power plant.

[0002] The present application claims priority based on Japanese patent application No. 2023-183616, which was filed in Japan on October 26, 2023, and the contents of which are incorporated herein by reference. State of the art

[0003] A combined cycle power plant, in which energy efficiency is improved by combining a gas turbine and a steam turbine, is known. In this plant, waste heat (for example, heat contained in the gas turbine's exhaust gas) is recovered from the gas turbine, for instance, by a heat recovery steam generator, and this recovered heat is used to generate steam. The steam produced by the heat recovery steam generator is then fed to the steam turbine, which is driven by the waste heat from the gas turbine.

[0004] In a combined cycle power plant with such a configuration, during normal operation, steam (main steam) generated by a main steam generating device, such as a heat recovery steam generator, is supplied to a section (steam load) in the plant that requires steam. For example, PTL 1 discloses a configuration in which steam generated by the heat recovery steam generator can be supplied to a stuffing box sealing section of the steam turbine that forms the combined cycle power plant. List of citations from patent literature

[0005] [PTL 1] Japanese unexamined patent application publication no. H9-32512 Summary of the invention: Technical problem

[0006] As described above, in a configuration where primary steam, generated by a primary steam generator such as a heat recovery steam generator, is supplied to the steam load, an auxiliary steam generator is provided to produce steam to supply the steam load instead of the primary steam generator when the plant, where steam cannot be generated by the primary steam generator, is started or stopped. An auxiliary boiler is considered as such an auxiliary steam generator, but the auxiliary boiler has a large number of components (equipment, instruments, control devices, and the like), and there is a problem with the increased costs of securing installation space and the maintenance costs to keep it operational.In particular, to improve the reliability (availability) of the auxiliary boiler as the auxiliary steam generating device, high maintenance costs must be incurred for regular inspection, preparation of spare parts in advance, and the like.

[0007] At least one embodiment of the present disclosure was made in view of the above circumstances, and one object of the present disclosure is to provide an auxiliary steam generating device which, in the event of starting or stopping a plant, can supply steam to a steam load while reducing operating costs, and a combined power plant. Solution to the problem

[0008] To solve the problem described above, an auxiliary steam generating device according to at least one embodiment of the present disclosure generates auxiliary steam for a steam load of a combined cycle power plant configured to drive a steam turbine by using steam generated by using waste heat from a gas turbine, wherein the auxiliary steam generating device comprises: a steam drum that stores the steam; a pressurized water heating unit that heats pressurized water from a water supply pump provided on a downstream side of the steam drum; a flash evaporation tank for flash evaporation of the pressurized water heated by the pressurized water heating unit; and a steam superheating unit that generates the auxiliary steam by superheating the steam produced in the expansion evaporation tank.

[0009] To solve the problem described above, a combined power plant according to at least one embodiment of the present disclosure comprises the auxiliary steam generating device according to at least one embodiment of the present disclosure. Advantageous effects of the invention

[0010] According to at least one embodiment of the present disclosure, it is possible to provide an auxiliary steam generating device that can supply steam to a steam load in the event of starting or stopping a plant, while reducing operating costs, and a combined power plant. Brief description of the drawings Fig. Figure 1 is a schematic configuration diagram of a combined cycle power plant according to one embodiment. Fig. Figure 2 is a schematic diagram showing a configuration of an auxiliary steam generating device. Fig. 1 together with an environment configuration. Fig. 3A is a configuration diagram that represents an operating state of a switching mechanism of Fig. 1 indicates when main steam is supplied to a steam load. Fig. 3B is a configuration diagram that shows an operating state of the switching mechanism of Fig. 1 indicates when auxiliary steam AS is supplied to the steam load. Fig. 4 is a modification example of Fig. 2. Description of embodiments

[0011] Some embodiments of the present invention are described below with reference to the accompanying drawings. However, the configurations described in the embodiments or shown in the drawings are not intended to limit the scope of protection of the invention and are merely examples for illustrative purposes.

[0012] Fig. Figure 1 is a schematic configuration diagram of a combined cycle power plant 1 according to one embodiment. The combined cycle power plant 1 includes a gas turbine 10, a heat recovery steam generator 20 which generates steam by using exhaust gas EG from the gas turbine 10, a steam turbine 60 which can be driven by the steam from the heat recovery steam generator 20, and a condenser 40 which condenses the steam from the steam turbine 60 into water.

[0013] The gas turbine 10 contains a compressor 11, which compresses combustion air, and a turbine 15, which is driven by combustion gas produced by mixing and burning the combustion air compressed by the compressor 11 and fuel supplied by a fuel supply system. A rotor of the compressor 11 and a rotor of the turbine 15 are connected to form a gas turbine rotor 19.

[0014] The steam turbine 60 comprises a high-pressure steam turbine HP, an intermediate-pressure steam turbine IP, and a low-pressure steam turbine LP. The high-pressure steam turbine HP, the intermediate-pressure steam turbine IP, and the low-pressure steam turbine LP share a steam turbine rotor 61, formed by interconnected rotating shafts. The steam turbine rotor 61 is integrally connected to the gas turbine rotor 19. The steam that has performed work in the steam turbine 60 is condensed into condensate in the condenser 40.

[0015] The condensate from the condenser 40 can be fed to the waste heat steam generator 20 via a condensate supply line 62. A low-pressure water supply pump 63 is provided in the condensate supply line 62, and the feedwater quantity of condensate to the waste heat steam generator 20 can be adjusted.

[0016] An auxiliary water tank 42 is connected to the condenser 40 via an auxiliary water supply line 41. An auxiliary water supply pump 43 is installed in the auxiliary water supply line 41, and in the event that the condensate in the condenser 40 is insufficient, auxiliary water can be supplied from the auxiliary water tank 42.

[0017] The waste heat steam generator 20 has a configuration for recovering heat (waste heat) contained in the exhaust gas EG from the gas turbine 10 and for effectively utilizing this heat. The waste heat steam generator 20 includes a low-pressure economizer 21, a low-pressure evaporator 22, a high-pressure primary economizer 23, a medium-pressure economizer 24, a medium-pressure evaporator 25, a low-pressure superheater 26, a high-pressure secondary economizer 27, a medium-pressure superheater 28, a high-pressure evaporator 29, a high-pressure primary superheater 30, a primary intermediate superheater 31, a secondary intermediate superheater 32, and a high-pressure secondary superheater 33 as a configuration for utilizing the heat recovered from the exhaust gas EG.

[0018] The exhaust gas, after the heat has been recovered in the waste heat steam generator 20, is released to the outside from a shaft 34.

[0019] In the waste heat steam generator 20, the feedwater (condensate) from the condenser 40 is first heated by the low-pressure economizer 21. At least a portion of the feedwater heated by the low-pressure economizer 21 is stored in a low-pressure drum 44. The low-pressure drum 44 is connected to the low-pressure evaporator 22, and steam can be generated from at least a portion of the water stored in the low-pressure drum 44. The steam generated by the low-pressure evaporator 22 is returned to the low-pressure drum 44.

[0020] Furthermore, the feedwater heated by the low-pressure economizer 21 is supplied to a high-pressure water supply pump 45 and a medium-pressure water supply pump 46. The high-pressure water supply pump 45 pressurizes the feedwater to a first pressure P1, and the medium-pressure water supply pump 46 pressurizes the feedwater to a second pressure P2, which is lower than the first pressure (< the first pressure P1). The feedwater pressurized to the first pressure P1 by the high-pressure water supply pump 45 is heated by the high-pressure primary economizer 23 and the high-pressure secondary economizer 27 and is then supplied to a high-pressure drum 47. The feedwater pressurized to the second pressure P2 by the medium-pressure water supply pump 46 is heated by the medium-pressure economizer 24 and is then supplied to a medium-pressure drum 48.

[0021] The high-pressure water supply pump 45 and the medium-pressure water supply pump 46 can be configured integrally.

[0022] The high-pressure drum 47 is connected to the high-pressure evaporator 29, and steam can be generated from at least some of the water stored in the high-pressure drum 47. The steam generated by the high-pressure evaporator 29 is returned to the high-pressure drum 47. The steam extracted from the high-pressure drum 47 is superheated by the high-pressure primary superheater 30 and the high-pressure secondary superheater 33 and is supplied to the high-pressure steam turbine HP. A first temperature reducer 49a is provided between the high-pressure primary superheater 30 and the high-pressure secondary superheater 33, and the temperature of the steam supplied to the high-pressure steam turbine HP can be adjusted.

[0023] The steam that has performed work in the high-pressure steam turbine HP is heated by the primary reheater 31 and the secondary reheater 32 and is supplied to the intermediate-pressure steam turbine IP. A second temperature reducer 49b is provided between the primary reheater 31 and the secondary reheater 32, and the temperature of the steam supplied to the intermediate-pressure steam turbine IP can be adjusted.

[0024] The intermediate pressure drum 48 is connected to the intermediate pressure evaporator 25, and steam can be generated from at least some of the water stored in the intermediate pressure drum 48. The steam generated by the intermediate pressure evaporator 25 is returned to the intermediate pressure drum 48. A portion of the steam extracted from the intermediate pressure drum 48 is heated by the intermediate pressure superheater 28 and fed to an outlet flow channel of the high-pressure steam turbine HP and then to the intermediate pressure steam turbine IP.

[0025] The low-pressure drum 44 is connected to the low-pressure evaporator 22, and steam can be generated from at least some of the water stored in the low-pressure drum 44. The steam generated by the low-pressure evaporator 22 is returned to the low-pressure drum 44. A portion of the steam extracted from the low-pressure drum 44 is heated by the low-pressure superheater 26 and fed to an outlet flow channel of the intermediate-pressure steam turbine IP and then to the low-pressure steam turbine LP. The steam that has performed work in the low-pressure steam turbine LP is returned to the condenser 40.

[0026] The combined cycle power plant 1 with the configuration described above includes a steam load SL, which requires steam SS during operation. In the present embodiment, a stuffing box sealing section of the steam turbine 60 (at least one from the high-pressure steam turbine HP, the intermediate-pressure steam turbine IP, and the low-pressure steam turbine LP) is described as an example of the steam load SL, but other configurations of the combined cycle power plant 1 can be used.

[0027] A main steam generating device and an auxiliary steam generating device 70 are provided as a configuration for supplying steam SS to the steam load SL. The main steam generating device is configured to generate a portion of the steam handled by the waste heat steam generator 20 as main steam MS and to supply the main steam MS to the steam load SL as steam SS. In particular, the main steam generating device is configured to extract the steam after use in the high-pressure steam turbine HP as main steam MS via a main steam supply line 91, which is connected to an outlet section of the high-pressure steam turbine HP, and to supply the main steam MS to the steam load SL as steam SS.

[0028] The auxiliary steam generating device 70 is configured such that, in a case where the main steam MS generated by the main steam generating device is insufficient, it generates auxiliary steam AS in place of the main steam generating device and supplies the auxiliary steam AS to the steam load SL as steam SS. Since the main steam generating device is configured as a section of the waste heat steam generator 20, as described above, the main steam MS may not be generated in sufficient quantity, for example, when the combined cycle power plant 1 is started or stopped. In such a case, the auxiliary steam generating device 70 can generate the auxiliary steam AS in place of the main steam MS from the main steam generating device and can supply the auxiliary steam AS to the steam load SL as steam SS.

[0029] Here, the configuration of the auxiliary steam generating device 70 is described with reference to Fig. 2 described. Fig. Figure 2 is a schematic diagram showing a configuration of the auxiliary steam generating device 70. Fig. 1 together with an environment configuration.

[0030] The auxiliary steam generating device 70 is configured to generate the auxiliary steam AS by using pressurized water PW, which is drawn from the high-pressure water supply pump 45, a water supply pump located downstream of the low-pressure drum 44. Specifically, the pressurized water PW is supplied to the auxiliary steam generating device 70 at the first pressure P1 via a pressurized water branch line 71, which branches off between the high-pressure water supply pump 45 and the high-pressure primary concentrator 23. A flow control valve 72 for adjusting the flow rate of the pressurized water PW supplied to the auxiliary steam generating device 70 is provided in the pressurized water branch line 71.

[0031] The pressurized water PW at the initial pressure P1, which is supplied to the auxiliary steam generating device 70 via the pressurized water branch line 71, is routed to a pressurized water heater 73 and heated. The pressurized water heater 73 can be a heat transfer heater that heats the pressurized water PW by consuming electrical energy, or it can be a heat exchanger that heats the pressurized water PW by exchanging heat with a heat transfer medium. In the latter case, the heat transfer medium can be supplied by any component of the combined cycle power plant 1.

[0032] The pressurized water PW, heated by the pressurized water heater 73, is fed to a flash evaporation tank 74. In the flash evaporation tank 74, the heated water PW is released at a high temperature and high pressure, and steam is generated by flash evaporation. The steam is superheated from the flash evaporation tank 74 by a steam superheater 75 and supplied to the steam load SL as auxiliary steam AS via an auxiliary steam supply line 78. The steam superheater 75 can be a heat transfer heater that superheats the steam by consuming electrical energy, or it can be a heat exchanger that heats the steam by exchanging heat with a heat transfer medium. In the latter case, the heat transfer medium can be supplied by any component of the combined cycle power plant 1.

[0033] The excess steam in the expansion evaporation tank 74 can be released as discharged steam DS via a steam vent line 76 to the outside. A flow control valve 77 for adjusting the flow rate of the discharged steam is provided in the steam vent line 76.

[0034] As described above, in the auxiliary steam generating device 70, the auxiliary steam AS for supplying the steam load SL can be generated by using pressurized water PW at high pressure from the high-pressure water supply pump 75, which is existing equipment provided in the combined cycle power plant 1. Generating the auxiliary steam AS, as described above, places less strain on installation space and maintenance costs compared to using an auxiliary boiler, and the auxiliary steam AS can be readily generated even during plant start-up or shutdown and can be supplied to the steam load SL as steam SS. In particular, in the present embodiment, the auxiliary steam AS can be efficiently generated by flash evaporation using pressurized water PW at high pressure.

[0035] Below, a switching mechanism 80 is described for switching between the main steam MS from the main steam generating device and the auxiliary steam AS from the auxiliary steam generating device 70 as the steam SS supplied to the steam load SL, with reference to Fig. 3A and Fig. 3B described. Fig. 3A is a configuration diagram showing an operating state of the switching mechanism 80 of Fig. 1 shows when the main steam MS is supplied to the steam load SL as the steam SS, and Fig. 3B is a configuration diagram showing an operating state of the switching mechanism 80 of Fig. Figure 1 shows when the auxiliary steam AS is supplied to the steam load SL as the steam SS.

[0036] As in Fig. 3A and Fig. As shown in Figure 3B, in the switching mechanism 80, the auxiliary steam supply line 78, to which the auxiliary steam AS is supplied from the auxiliary steam generating device 70, and the main steam supply line 91, to which the main steam MS is supplied from the main steam generating device, are combined at a connection point G and are connected to a steam supply line 94 for supplying the steam SS to the steam load SL. A flow control valve 83 for adjusting the flow rate of the auxiliary steam AS and a check valve 84 for preventing backflow of the auxiliary steam AS are provided in the auxiliary steam supply line 78. Furthermore, a flow control valve 92 for adjusting the flow rate of the main steam MS and a check valve 93 for preventing backflow of the main steam MS are provided in the main steam supply line 91. Additionally, a flow control valve 95 for adjusting the flow rate of the steam SS is provided in the steam supply line 94.

[0037] An auxiliary steam discharge line 81 for discharging the auxiliary steam AS to the outside branches off from an upstream side of the flow control valve 83 in the auxiliary steam supply line 78. A vent valve 82 is provided in the auxiliary steam discharge line 81, and the discharge rate of the auxiliary steam AS can be adjusted by the opening degree of the vent valve 82.

[0038] In the present embodiment, a right side (that is, the side of main steam supply line 91 and steam supply line 94) of the connection point is in Fig. 3A and Fig. 3B is configured as a steam supply unit 90. The steam supply units 90 are connected in parallel and are configured to supply the main steam MS from each steam supply unit 90 to several steam loads SL of the combined cycle power plant 1 as steam SS. By connecting the auxiliary steam supply line 78 to each steam supply unit 90 that can supply the main steam MS to the steam load SL, if it is difficult to supply the main steam MS as steam SS, the auxiliary steam AS can be supplied as steam SS instead of the main steam MS. Such a configuration can be realized, for example, by adding the auxiliary steam generating device 70 to the existing configuration, which consists of the steam supply unit 90 that can only supply the main steam MS as steam SS via the auxiliary steam supply line 78.

[0039] As in Fig. As shown in Figure 3A, for example, if it is difficult to supply the main steam MS from the main steam generating device, as in the case of starting or stopping the combined cycle power plant 1, the switching mechanism 80 reverses the flow channel to supply the auxiliary steam AS from the auxiliary steam generating device 70 to the steam load SL as the steam SS. In a case where the supply quantity of the main steam MS from the main steam generating device is low, the supply pressure of the main steam MS from the main steam supply line 91 is low, and thus the pressure of the auxiliary steam AS from the auxiliary steam supply line 78 is dominant, so that, as shown in Figure 3A, the main steam supply pressure is reduced by the auxiliary steam supply line 78. Fig. Figure 3A shows that the auxiliary steam AS is supplied from the auxiliary steam supply line 78 from the connection point G via the steam supply line 94 to the steam load SL. In this case, since the check valve 93 is provided in the main steam supply line 91, the ingress (backflow) of the auxiliary steam AS into the main steam supply line 91 is prevented.

[0040] On the other hand, as in Fig. Figure 3B shows, for example, in a case where the main steam MS can be supplied from the main steam generating device, as in a case of normal operation of the combined cycle power plant 1, the switching mechanism 80 reverses the flow channel to supply the main steam MS from the main steam generating device to the steam load SL as steam SS. In a case where the supply quantity of main steam MS from the main steam generating device is sufficient, the supply quantity of auxiliary steam AS from the auxiliary steam generating device 70 is reduced (for example, the production quantity of auxiliary steam AS in the auxiliary steam generating device 70 itself can be reduced, or part of the auxiliary steam AS produced by the auxiliary steam generating device 70 can be discharged to the outside via the auxiliary steam discharge line 81). As a result, the supply pressure of the main steam MS from the main steam supply line 91 is dominant over the supply pressure of the auxiliary steam AS, so that, as shown in Figure 3B, the supply pressure of the main steam MS from the main steam supply line 91 is dominant over the supply pressure of the auxiliary steam AS. Fig. As shown in Figure 3B, the main steam MS is supplied from the main steam supply line 91 at connection point G via the steam supply line 94 to the steam load SL. In this case, since the check valve 84 is provided in the auxiliary steam supply line 78, the ingress (backflow) of the main steam MS into the auxiliary steam supply line 78 is prevented.

[0041] Fig. 4 is a modification example of Fig. 2. In this modification example, the auxiliary steam generating device 70 is configured to generate the auxiliary steam AS by using the pressurized water PW captured by the intermediate-pressure water supply pump 46, which is a water supply pump provided on the downstream side of the low-pressure drum 44. In particular, the pressurized water PW is supplied to the auxiliary steam generating device 70 via a pressurized water branch line 71' that branches off between the intermediate-pressure water supply pump 46 and the intermediate-pressure primary conomizer 24.

[0042] In this case, the pressurized water PW introduced into the auxiliary steam generating device 70 has a second pressure P2, which is lower than the first pressure P1. Therefore, the steam generation efficiency in the flash evaporation tank 75 is lower than in the embodiment described above (see Fig. 2), but the pressure resistance requirements of each component for generating the auxiliary steam (each component or line through which the pressurized water PW flows, in particular the pressurized water branch line 71', the flow control valve 72, the pressurized water heater 73 and the like) can be reduced, and the auxiliary steam generating device 70 can be implemented at a lower cost.

[0043] As described above, according to each of the embodiments described above, the auxiliary steam AS can be generated by using the auxiliary steam generating device 70 without using an auxiliary boiler, which requires a large installation space and incurs high maintenance costs. The auxiliary steam AS can be supplied to the steam load SL instead of the main steam in a case such as when starting or stopping the combined cycle power plant 1.

[0044] Furthermore, it is possible to suitably replace the components in the embodiment described above with known components within the scope of protection, which does not deviate from the core of the present disclosure, and the embodiments described above can be suitably combined.

[0045] For example, the content described in each of the embodiments described above is understood as follows. (1) An auxiliary steam generating device according to one aspect generates auxiliary steam for a steam load of a combined cycle power plant configured to drive a steam turbine by using steam generated by using waste heat from a gas turbine, the auxiliary steam generating device comprising: a steam drum that stores the steam; a pressurized water heating unit that heats pressurized water from a water supply pump provided on a downstream side of the steam drum; a flash evaporation tank for flash evaporation of the pressurized water heated by the pressurized water heating unit; and a steam superheating unit that generates the auxiliary steam by superheating the steam produced in the expansion evaporation tank.

[0046] According to aspect (1), the pressurized water from the water supply pump provided in the combined cycle power plant is heated by the pressurized water heating unit. The heated pressurized water is then expanded in the flash evaporator tank to generate steam. The generated steam is superheated by the steam superheater to produce high-temperature auxiliary steam. As described above, the auxiliary steam for supplying the steam load can be generated using the pressurized water from the water supply pump, which is existing equipment provided in the combined cycle power plant. Generating the auxiliary steam represents a less demanding task in terms of installation space and maintenance costs compared to using an auxiliary boiler, and the auxiliary steam can be readily supplied even during plant start-up or shutdown.

[0047] (2) In another aspect, in aspect (1) the water supply pump is provided between the steam drum and a heat exchanger configured to heat feed water from the water supply pump by heat exchange with the waste heat on the downstream side of the water supply pump.

[0048] According to aspect (2), the water supply pump, which captures the pressurized water from the outlet section to generate the auxiliary steam, is provided between the steam drum and the heat exchanger, which is located on the downstream side of the water supply pump.

[0049] (3) In another aspect, in aspect (1) or (2), the combined power plant includes, as the water supply pump, a high-pressure water supply pump configured to supply first pressurized water at a first pressure, and a medium-pressure water supply pump configured to supply second pressurized water at a second pressure lower than the first pressure, and The pressurized water is the first pressurized water.

[0050] According to aspect (3), the auxiliary steam is generated by the first pressurized water from the high-pressure water supply pump provided in the combined cycle power plant. Since the first pressurized water has a higher pressure than the second pressurized water, the auxiliary steam can be generated more efficiently by flash evaporation.

[0051] (4) In another aspect, in aspect (1) or (2), the combined power plant includes as the water supply pump a high-pressure water supply pump configured to supply first pressurized water at a first pressure, and a medium-pressure water supply pump configured to supply second pressurized water at a second pressure lower than the first pressure, and the pressurized water is the second pressurized water.

[0052] According to aspect (4), the auxiliary steam is generated by the second pressurized water from the medium-pressure water supply pump provided in the combined cycle power plant. Since the second pressurized water has a lower pressure than the first pressurized water, the pressure resistance requirements of each component (equipment or piping through which the pressurized water flows) for generating the auxiliary steam can be reduced, and the auxiliary steam generation device can be implemented at a lower cost.

[0053] (5) In another aspect, in one of aspects (1) to (4), the steam load is a stuffing box sealing section of a steam turbine configured to be driven by the steam generated by the waste heat.

[0054] According to aspect (5), the auxiliary steam can be appropriately supplied to the stuffing box sealing section of the steam turbine forming the combined cycle power plant, for which steam supply is required during operation even in the case of starting or stopping the plant.

[0055] (6) A combined power plant according to one aspect includes: an auxiliary steam supply line which supplies the auxiliary steam from the auxiliary steam generating device according to one of (1) to (5) to the steam load; a main steam supply line that delivers main steam from a main steam generating device to the steam load; and a switching mechanism that switches between the auxiliary steam supply and the main steam supply.

[0056] According to aspect (6), the main steam from the main steam generating device and the auxiliary steam from the auxiliary steam generating device can be switched as the steam supplied to the steam load of the combined cycle power plant. Consequently, for example, in a case where the supply of main steam is not possible, such as in the case of starting or stopping the combined cycle power plant, the auxiliary steam can be supplied instead of the main steam. Reference symbol list 1 Combined Heat and Power Plant 10 Gas turbine 11 Compressor 12 Combustion chamber 15 Turbine 19 Gas turbine rotor 20 waste heat steam generators 21 Low-pressure economists 22 Low-pressure evaporators 23 High-pressure primary economizers 24 Medium Pressure Economists 25 medium-pressure evaporators 26 Low-pressure superheaters 27 High-pressure secondary economizers 28 Medium-pressure superheaters 29 High-pressure evaporators 30 high-pressure primary superheaters 31 Primary intermediate superheater 32 Secondary Intermediate Superheaters 33 High-pressure secondary superheaters 34 Shaft 40 Capacitor 41 Additional water supply line 42 Additional water tank 43 Auxiliary water supply pump 44 Low-pressure drum 47 High-pressure drum 48 Medium pressure drum 49a first temperature reducer 49b second temperature reducer 60 steam turbine 61 Steam turbine rotor 62 Condensate drain 63 Low-pressure water supply pump 70 Auxiliary steam generating device 71 Pressurized water branch line 72 Flow control valve 73 Pressurized water heating 74 Relaxation evaporation tank 75 steam superheaters 76 Steam vent line 77 Flow control valve 78 Auxiliary steam supply line 80 switching mechanism 81 Auxiliary steam discharge line 82 Vent valve 90 Steam supply unit 91 Main steam supply 83 Flow control valve 84 Check valve 92 Flow control valve 93 Check valve 94 Steam supply line 95 Flow control valve PW pressurized water AS auxiliary steam MS Main Steam SL steam load DS emitted steam SS Steam QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-183616

[0002] JP 9-32512

[0005]

Claims

Auxiliary steam generating device that produces auxiliary steam for a steam load of a combined cycle power plant configured to drive a steam turbine by using steam generated by utilizing waste heat from a gas turbine, the auxiliary steam generating device comprising: a steam drum for storing the steam; a pressurized water heating unit for heating pressurized water from a water supply pump provided on a downstream side of the steam drum; a flash evaporation tank for flash evaporation of the pressurized water heated by the pressurized water heating unit; and a steam superheating unit for producing the auxiliary steam by superheating the steam generated in the flash evaporation tank. Auxiliary steam generating device according to claim 1, wherein the water supply pump is provided between the steam drum and a heat exchanger configured to heat feed water from the water supply pump by heat exchange with the waste heat on the downstream side of the water supply pump. Auxiliary steam generating device according to claim 1 or 2, wherein the combined power plant comprises, as the water supply pump, a high-pressure water supply pump configured to supply first pressurized water at a first pressure, and a medium-pressure water supply pump configured to supply second pressurized water at a second pressure lower than the first pressure, and the pressurized water is the first pressurized water. Auxiliary steam generating device according to claim 1 or 2, wherein the combined power plant comprises, as the water supply pump, a high-pressure water supply pump configured to supply first pressurized water at a first pressure, and a medium-pressure water supply pump configured to supply second pressurized water at a second pressure lower than the first pressure, and the pressurized water is the second pressurized water. Auxiliary steam generating device according to claim 1 or 2, wherein the steam load is a stuffing box sealing section of a steam turbine configured to be driven by the steam generated by the waste heat. Combined power plant comprising: an auxiliary steam supply line that supplies the auxiliary steam from the auxiliary steam generating device according to claim 1 or 2 to the steam load; a main steam supply line that supplies main steam from a main steam generating device to the steam load; and a switching mechanism that switches between the auxiliary steam supply line and the main steam supply line.

Images