WO2007083478A1

WO2007083478A1 - Steam turbine cycle

Info

Publication number: WO2007083478A1
Application number: PCT/JP2006/325524
Authority: WO
Inventors: Koichi Goto; Nobuo Okita
Original assignee: Kabushiki Kaisha Toshiba
Priority date: 2006-01-20
Filing date: 2006-12-21
Publication date: 2007-07-26
Also published as: KR20080038233A; EP1965043A1; JP2007192152A; US20090094983A1; EP1965043B1; CN101300407B; JP4621597B2; EP1965043A4; CN101300407A

Abstract

A steam turbine cycle which comprises a high pressure turbine (1), a reheat turbine (24), a boiler (4), a heater (6) for heating supply water to the boiler (4) with extraction steam from the turbines (1, 24), a water supply pump (12), and a condenser (10), and which is a single-stage reheat cycle where the working fluid is water and Rankine cycle as a regenerative cycle. Steam temperature at the outlet of the boiler (4) is 590°C or above. The cycle is constituted such that the temperature rise ratio between supply water temperature rise at a first supply water heater (7) corresponding to extraction steam (high pressure turbine exhaust gas extraction steam) (22) from exhaust gas of the high pressure turbine (1) and an average of supply water temperature rises at a second supply water heater (8) where the pressure of supply water is lower than that of first supply water heater (7) falls within a range of 1.9-3.5.

Description

Specification

Steam turbine cycle

Technical field

[0001] The present invention relates to a steam turbine cycle having high cycle thermal efficiency.

Background art

[0002] As a conventional technique, one of steam turbine cycles used in a thermal power plant or the like will be described with reference to FIG.

[0003] Boiler feed water 14 is heated by using, for example, fuel combustion heat in boiler 4 to generate superheated steam (hereinafter referred to as main steam 16) having a sufficiently high temperature. This superheated steam may be a supercritical fluid.

[0004] The main steam 16 flows into the high-pressure turbine 1, flows while expanding, and decreases in both pressure and temperature.

[0005] Most of the high-pressure turbine exhaust 21 that has flowed out of the high-pressure turbine 1 flows into the reheater 5, becomes higher in temperature, becomes reheated steam 17, and flows into the intermediate-pressure turbine 2.

[0006] The steam that flows while expanding in the intermediate pressure turbine 2 decreases in both pressure and temperature and flows into the low pressure turbine 3.

[0007] The steam that flows while expanding in the low-pressure turbine 3 decreases in both pressure and temperature, but in some cases, it is often in the state of saturated steam that is liquid water. This saturated steam is cooled by the condenser 10 using seawater or the atmosphere 23 or the like to become the condensate 25. Condensate 25 is sent to feed water heater 6 by condensate pump 11 and becomes boiler feed water 14. The medium pressure turbine 2 and the low pressure turbine 3 are reheat turbines 24.

In FIG. 1, eight feed water heaters 6 are shown. The boiler feed water is extracted by the extracted steam 20 extracted from the extracted position 31 in the flow path of the high pressure turbine 1, the intermediate pressure turbine 2, and the low pressure turbine 3. Heat water 14. Here, the higher-pressure feed water heater 6 has a configuration in which higher-pressure extraction air flows.

In FIG. 1, the low-pressure turbine 3 is depicted as a double flow, and the force is depicted as if only one side of the low-pressure turbine 3 has been extracted. After that, it flows into the feed water heater 6. It should be noted that the feed water heater 6 may be configured to extract one side of the low pressure turbine 3 on one side.

[0010] The feed water heater 6 has a surface type and a mixing type. In the surface water heater, the extracted steam 20 is condensed by heat exchange with the water supply via the heat transfer surface to become drain water 15, and in principle, the lower pressure water supply is made while sequentially flowing in from the higher pressure water heater 6. Flows to heater 6. The drain water 15 of the lowest pressure feed water heater 6 flows to the condenser 10. The drain water 15 may be joined to the feed water by the drain water pump 13.

[0011] The mixed feed water heater has a structure in which the extracted air is directly mixed with the feed water and heated, and the deaerator 9 that desorbs oxygen and the like dissolved in the feed water is a mixed feed water heater. Included in the bowl.

[0012] Immediately after the mixed feed water heater, a feed water pump 12 is provided to send feed water to the higher pressure feed water heater 6. In Fig. 1, the extraction to the mixed feed water heater is medium pressure turbine exhaust extraction 32, but this need not be the case. The deaerator 9 is not necessary, but if not, the feed water pump 12 is provided at an appropriate position among the plurality of feed water heaters 6. The feed water heated by all feed water heaters 6 flows into the boiler 4.

In FIG. 1, the high-pressure turbine 1, the intermediate-pressure turbine 2, and the low-pressure turbine 3 are connected by a single rotating shaft 19 and connected to a generator 18. By expanding inside the high-pressure turbine 1, the medium-pressure turbine 2, and the low-pressure turbine 3, the enthalbi held by the steam is converted into shaft power and is generated by the generator 18. It is not necessary to connect each turbine with one rotating shaft 19 and connect it to one generator 18.

[0014] In FIG. 1, the low-pressure turbine 3 is depicted as a double flow. This is a structure in which the incoming steam is divided into two parts and flows into the two low-pressure turbines 3, and may be divided into four parts or not. Further, in FIG. 1, the medium pressure turbine 2 may be a force double flow depicted as a single flow. Further, in FIG. 1, the intermediate pressure turbine 2 and the low pressure turbine 3 may include only one power reheating turbine 24 depicted as separate steam turbines.

[0015] Both the regeneration cycle using the extracted steam 20 and the reheat cycle in which the high-pressure turbine exhaust 21 is heated by the reheater 5 and flows into the reheat turbine 24 are modified Rankine cycles, and are simple. Rankine cycle force Improves thermal efficiency. In the case of a power plant, the thermal efficiency is almost equal to power generation divided by boiler heat input. [0016] The cycle thermal efficiency varies depending on the cycle configuration, but also varies depending on the temperature and flow rate of each extraction steam 20. In particular, with the progress of high-temperature materials in recent years, there is room to improve the cycle configuration under the high-temperature conditions of steam, where the temperature of steam is increasing and the cycle thermal efficiency is increasing.

[0017] In addition, the non-patent literature states that "the heater enthalpy increase due to extraction from the reheat point is about 1.8 times the average enthalpy increase in the low-pressure heater is the optimum performance". "¾team Turoine Performance ana conomics" Invention Disclosure

Problems to be solved by the invention

[0018] An object of the present invention is to provide a steam turbine cycle with high cycle thermal efficiency.

Means for solving the problem

[0019] The invention according to claim 1 includes a high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by the extracted steam from the turbine, a feed water pump, and a condensate. In the Rankine cycle, where the working fluid is water and the Rankine cycle is a regeneration cycle, the steam temperature at the boiler outlet is 590 ° C or higher, and is from the exhaust of the high-pressure turbine. The temperature increase ratio between the increase in the feed water temperature in the first feed water heater corresponding to the bleed air and the average of the feed water temperature rise in the second feed water heater whose feed water is lower than that in the first feed water heater is 1.9. This is a steam turbine cycle characterized by being 3.5 or less.

[0020] The present invention according to claim 2 includes a high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by extracted steam from the turbine, a feed water pump, and a condensate. In the Rankine cycle, the working fluid is water, and the Rankine cycle is a regeneration cycle, the steam temperature at the boiler outlet is 590 ° C or higher, and the exhaust gas from the high-pressure turbine is exhausted. Ratio of increase in water supply enthalpy in the first feed water heater corresponding to the bleed air and average increase in water supply enthalpy in the second water supply heater whose supply water pressure is lower than that in the first water supply heater. The enthalpy increase ratio is 1.9 to 3.5 It is the steam turbine cycle characterized by being.

[0021] The invention according to claim 3 includes a high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by extracted steam from the turbine, a feed water pump, and a condensate. In the Rankine cycle, where the working fluid is water and the Rankine cycle is a regeneration cycle, the steam temperature at the boiler outlet is 590 ° C or higher, and is from the exhaust of the high-pressure turbine. The temperature rise ratio between the rise in the feed water temperature in the first feed water heater corresponding to the bleed air and the average rise in the feed water temperature in the feed water heater excluding the first feed water heater is 1.9 to 3.5. It is a featured steam turbine cycle.

[0022] The invention according to claim 4 includes a high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by extracted steam from the turbine, a feed water pump, and a condensate. In the Rankine cycle, where the working fluid is water and the Rankine cycle is a regeneration cycle, the steam temperature at the boiler outlet is 590 ° C or higher and the exhaust gas from the high-pressure turbine is exhausted. The increase in the specific enthalpy of the feed water in the first feed water heater corresponding to the bleed air and the average rise in the specific enthalpy of the feed water heater excluding the first feed water heater is L9 or more 3.5 The steam turbine cycle is characterized by the following.

The invention's effect

[0023] According to the present invention, it is possible to provide a steam turbine cycle with high cycle thermal efficiency.

Brief Description of Drawings

[0024] FIG. 1 is a schematic diagram showing first to eleventh and eleventh embodiments of a steam turbine cycle according to the present invention and the prior art.

FIG. 2 is a schematic diagram showing ninth to eleventh embodiments of a steam turbine cycle according to the present invention.

FIG. 3 is a schematic diagram showing the relationship between temperature rise ratio and thermal efficiency.

BEST MODE FOR CARRYING OUT THE INVENTION

[0025] Form of the first implementation

Hereinafter, a first embodiment of a steam turbine cycle according to the present invention will be described with reference to the drawings. Here, FIG. 1 is a diagram showing a first embodiment of the present invention. [0026] The steam turbine cycle of the present embodiment heats the feed water to the boiler 4 by the extracted steam from the high pressure turbine 1, the reheat turbine 24, the boiler 4, and the high pressure turbine 1 and the reheat turbine 24. It is equipped with a feed water heater 6, a feed water pump 12, and a condenser 10, and constitutes a Rankine cycle that is a one-stage reheat cycle in which the working fluid is water and a regeneration cycle

[0027] The steam temperature at the outlet of the boiler 4 is 590 ° C or higher, and the feed water temperature rises in the first feed water heater 7 corresponding to the bleed air from the high pressure turbine exhaust 21 (high pressure turbine exhaust bleed air) 22. Thus, the temperature rise ratio with the average of the feed water temperature rise in the second feed water heater 8 where the feed water is lower than that in the first feed water heater 7 is 1.9 to 3.5.

[0028] By adjusting the flow rate of each extraction steam 20 and each extraction position 31, an increase in the feed water temperature in the first feed water heater 7 and the second feed water heater 8 can be adjusted. When changing the temperature of the high-pressure turbine exhaust bleed 22 or the medium-pressure turbine exhaust bleed 32, the exhaust specifications of the high-pressure turbine 1 and the intermediate-pressure turbine 2 are changed.

[0029] Since the water supply temperature at the inlet of boiler 4 is often specified on the boiler 4 side, optimization calculation was performed with the value fixed. As a result, when the temperature rise ratio was 1.9 or more and 3.5 or less, cycle thermal efficiency Became the maximum.

[0030] The temperature rise ratio between the increase in feed water temperature in the first feed water heater 7 and the average rise in feed water temperature in the second feed water heater 8 is the number of feed water heaters 6, steam such as exhaust loss, etc. The range varies depending on the mechanical differences of the turbine, the scale corresponding to the power generation output at the power plant, and the difference in fine structure.

[0031] As described above, in non-patent literature, there is a description that 1.8 is the best as the specific enthalpy increase ratio, but in the range of the temperature increase ratio, it is normal that the specific enthalpy increase ratio is 1.8. It is not a power plant.

[0032] This event is presumed to be due to the following reason.

[0033] Since the output of the steam turbine is the sum of the "heat drop, that is, the small amount of Xenthalpi reduction X steam mass flow rate" in each stage of each turbine, the specific force is as low as possible. Since the boiler feed water 14 will be heated later, the efficiency is increased. However, on the other hand, boiler feed water 14 boiler 4 inlet temperature is high Since the efficiency of the regeneration cycle is higher, it is necessary to consider the effect.

[0034] When the boiler 4 inlet temperature is specified, the steam pressure in the vessel is the highest, and steam having the same saturation temperature as the boiler 4 inlet temperature of the feed water heater 26 is required, and the pressure of the extraction steam 20 is specified. The other feed water heaters 7, 8 will cover the temperature rise up to that step by step.

[0035] The high-pressure turbine exhaust extraction 22 is a steam having a relatively high pressure and low specific enthalpy, and is not extracted from the steam heated by the reheater 5, and therefore, the high-pressure turbine exhaust extraction 22 If the boiler feed water 14 is heated more often using the heat, the thermal efficiency of the entire cycle will increase.

That is, as schematically shown in FIG. 3, the temperature rise ratio has a predetermined optimum value that provides the best thermal efficiency, and this optimum value should be sufficiently higher than 1. This optimum value depends on the conditions of the main steam16, and it is estimated that the high steam value will be higher.

[0037] As described above, by setting the temperature rise ratio between the feed water temperature rise in the first feed water heater 7 and the average feed water temperature rise in the second feed water heater 8 to 1.9 or more and 3.5 or less, the cycle Thermal efficiency can be improved.

[0038] Second Embodiment

Next, a second embodiment of the present invention will be described with reference to FIG.

[0039] The steam turbine cycle of the present embodiment heats feed water to the boiler 4 by the high-pressure turbine 1, the reheat turbine 24, the boiler 4, and the extracted steam from the high-pressure turbine 1 and the reheat turbine 24. A feed water heater 6, a feed water pump 12, and a condenser 10 are provided to constitute a Rankine cycle that is a one-stage reheat cycle in which the working fluid is water and a regeneration cycle.

[0040] Further, the steam temperature at the outlet of the boiler 4 is 590 ° C or higher, the rise in the specific enthalpy of the feed water in the first feed water heater 7 corresponding to the high pressure turbine exhaust bleed air 22 and the first feed water heater 7 Furthermore, the ratio of the increase in enthalpy to the average of the increase in the specific enthalpy of the feed water in the second feed water heater 8 whose supply water is low is 1.9 to 3.5.

[0041] By adjusting the flow rate of each extraction steam 20 and each extraction position 31, it is possible to adjust the specific enthalpy increase of the supply water in the first feed water heater 7 and the second feed water heater 8. When changing the specific enthalpy for the extracted steam 20 from the high-pressure turbine exhaust bleed 22 or the medium-pressure turbine exhaust bleed 32, the exhaust performance of the high-pressure turbine 1 and the intermediate-pressure turbine 2 is changed. Will be changed.

[0042] Since the feed water temperature at the inlet of boiler 4 is often specified on the boiler 4 side, the optimization calculation was performed with a fixed value. Thermal efficiency was maximized.

[0043] The increase ratio of specific enthalpy depends on the mechanical differences of steam turbines such as the number of feed water heaters 6, exhaust loss, etc., the scale corresponding to the power generation output in the power plant, and the difference in fine structure. There is a range width.

[0044] As described above, in non-patent literature, there is a description that 1.8 is the best as the specific enthalpy increase ratio, but in this literature, the temperature of the main steam 16 is not described and is assumed. Since the main steam 16 temperature is different, the optimum value of the specific enthalpy increase ratio is considered to be different.

[0045] In the case of the present embodiment as well, as in the first embodiment described above, as schematically shown in Fig. 3, the specific enthalpy increase ratio has a predetermined optimum value that provides the best thermal efficiency, This optimal value is better if the ratio of rise in specific enthalpy is sufficiently higher than 1. This optimum value depends on the conditions of main steam 16 and is estimated to be higher for high temperature steam.

[0046] As described above, the ratio of the increase in the specific enthalpy of the feed water in the first feed water heater 7 to the average of the increase in the specific enthalpy of the feed water in the second feed water heater 8 is 1.9 to 3.5. By doing so, the cycle thermal efficiency can be improved.

[0047] Third Embodiment

Next, a third embodiment of the present invention will be described with reference to FIG.

[0048] The steam turbine cycle of the present embodiment heats feed water to the boiler 4 by the high-pressure turbine 1, the reheat turbine 24, the boiler 4, and the extracted steam from the high-pressure turbine 1 and the reheat turbine 24. A feed water heater 6, a feed water pump 12, and a condenser 10 are provided, which is a one-stage reheat cycle in which the working fluid is water and a Rankine cycle that is a regeneration cycle.

[0049] In addition, the steam temperature at the outlet of the boiler 4 is 590 ° C or higher, excluding the rise in feed water temperature in the first feed water heater 7 corresponding to the high pressure turbine exhaust bleed 22 and the first feed water heater 7 The ratio of temperature rise to the average of the feed water temperature rise in the feed water heater is 1.9 to 3.5. [0050] Here, the feed water heaters excluding the first feed water heater 7 are the second feed water heater 8 whose feed water has a lower pressure than the first feed water heater 7, and the first feed water heater 7 In addition, all are combined with the third water heater 26, which has a higher water supply pressure. The third feed water heater 26 heats the feed water with the extracted steam from inside the high pressure turbine 1.

[0051] By adjusting the flow rate of each extraction steam 20 and each extraction pressure position 31, the feed water temperature rise in the first feed water heater 7, the second feed water heater 8, and the third feed water heater 26 Can be adjusted. When changing the temperature of the high-pressure turbine exhaust bleed 22 or the medium-pressure turbine exhaust bleed 32, the exhaust specifications of the high-pressure turbine 1 and the intermediate-pressure turbine 2 are changed.

[0052] Since the feed water temperature at the inlet of boiler 4 is often specified on the boiler 4 side, optimization calculation was performed with the value fixed. As a result, when the temperature rise ratio was 1.9 or more and 3.5 or less, cycle thermal efficiency Became the maximum.

[0053] The temperature rise ratio between the feed water temperature rise in the first feed water heater 7 and the average feed water temperature rise in the feed water heaters 8 and 26 excluding the first feed water heater 7 is There is a range of effects due to differences in steam turbine machinery such as the number and exhaust loss, as well as the scale, details, and configuration differences corresponding to the power generation output in the power plant.

[0054] As described above, the temperature increase ratio between the increase in the feed water temperature in the first feed water heater 7 and the average rise in the feed water temperature in the feed water heaters 8 and 26 excluding the first feed water heater 7 is 1.9 or more. 3.5 By making it 5 or less, cycle thermal efficiency can be improved as in Example 1.

[0055] Form of the fourth implementation

Next, a fourth embodiment of the present invention will be described with reference to FIG.

[0056] The steam turbine cycle of the present embodiment heats the feed water to the boiler 4 by the high-pressure turbine 1, the reheat turbine 24, the boiler 4, and the extracted steam from the high-pressure turbine 1 and the reheat turbine 24. A feed water heater 6, a feed water pump 12, and a condenser 10 are provided to constitute a Rankine cycle that is a one-stage reheat cycle in which the working fluid is water and a regeneration cycle.

[0057] The steam temperature at the outlet of the boiler 4 is 590 ° C or higher, excluding the rise in the specific water supply enthalpy in the first feed water heater 7 corresponding to the high pressure turbine exhaust bleed 22 and the first feed water heater 7. The ratio of the increase in the specific enthalpy to the average increase in the supply water in the feed water heaters 8 and 26 is 1.9 to 3.5.

[0058] By adjusting the flow rate of each extraction steam 20 and each extraction position 31, the specific enthalpy of the supply water in the first feed water heater 7, the second feed water heater 8, and the third feed water heater 26 is increased. Can be adjusted. When changing the specific enthalpy for the high pressure turbine exhaust bleed 22 and the medium pressure turbine exhaust bleed 3 2, the exhaust specifications of the high pressure turbine 1 and the intermediate pressure turbine 2 are changed.

[0059] Since the feed water temperature at the inlet of boiler 4 is often specified on the boiler 4 side, the optimization calculation was performed with a fixed value. Thermal efficiency was maximized.

[0060] The specific enthalpy increase ratio of the feed water in the first feed water heater 7 and the average rise in the specific enthalpy rise in the feed water heaters 8 and 26 excluding the first feed water heater 7 is There are range ranges due to the difference in the number of feed water heaters 6, steam turbine mechanical differences such as exhaust loss, the scale corresponding to the power generation output in the power plant, and the difference in fine configuration.

[0061] As described above, the ratio of the increase in the specific enthalpy of the feed water in the first feed water heater 7 and the average of the increase in the specific enthalpy of the feed water in the feed water heaters 8 and 26 excluding the first feed water heater 7. By setting the enthalpy increase ratio to 1.9 or more and 3.5 or less, cycle thermal efficiency can be improved as in the second embodiment.

[0062] Form of fifth implementation

Next, a fifth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment shown in FIG. 1, the feed water temperature rise in the second feed water heater 8 is calculated by adding the feed water temperature rise by the feed water pump 12, and the others are the first embodiment. It is almost the same as the embodiment

[0063] Since the feed water pump 12 heats the feed water, the temperature of the feed water rises. Therefore, by adding this temperature rise, the average temperature rise per unit of the second feed water heater 8 is calculated.

[0064] In the third embodiment, the increase in the feed water temperature in the feed water heaters 8 and 26 excluding the first feed water heater 7 is calculated by adding the rise in the feed water temperature by the feed water pump 12. Chisaru

[0065] Again, since the feed water pump 12 heats the feed water, the temperature of the feed water rises. Therefore, by adding this temperature rise, the average temperature rise per feed water heater 8, 26 excluding the first feed water heater 7 is calculated.

[0066] Since the feed water temperature at the inlet of boiler 4 is often specified on the boiler 4 side, optimization calculation was performed with the value fixed. As a result, when the temperature rise ratio was 1.9 or more and 3.5 or less, the cycle thermal efficiency Became the maximum.

[0067] In addition, because of the reason described in the first embodiment, there is also the influence of the heat generation difference due to the mechanical difference of the feed water pump 12, so the temperature rise ratio has a range width as described above. Has occurred

[0068] As described above, the first water supply temperature increase in the second water heater 8 is calculated by adding the temperature increase of the water supply by the water supply pump 12, and then the temperature increase ratio is defined to thereby perform the first implementation. As in the present embodiment and the third embodiment, the cycle thermal efficiency can be improved.

[0069] Sixth embodiment

Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment shown in FIG. 1 is calculated based on the increase in the specific enthalpy of the feed water by the feed water pump 8 in the second feed water heater 8 and the others. This is substantially the same as the first embodiment.

[0070] The feed water pump 12 boosts the feed water, and further heats the feed water as described in the third embodiment, so that the specific enthalpy of the feed water rises. By adding this increase in the specific enthalpy, the average specific enthalpy increase per unit of the second feed water heater 8 is calculated.

[0071] Further, in the present embodiment, in the above-described fourth embodiment, the increase in the specific enthalpy of the feed water in the feed water heaters 8 and 26 excluding the first feed water heater 7 is caused by the feed water pump 12 It can also be calculated by adding an increase in specific enthalpy.

[0072] Again, the feed water pump 12 boosts the feed water, and further heats the feed water as described in the third embodiment, so that the specific enthalpy of the feed water increases. In view of this rise in the enthalpy, per unit of feed water heaters 8, 26 excluding the first feed water heater 7 Calculate the average specific enthalpy increase.

[0073] Since the water supply temperature at the inlet of boiler 4 is often specified on the boiler 4 side, the optimization calculation was performed with a fixed value. When the specific enthalpy increase ratio was 1.9 or more and 3.5 or less, the cycle was Thermal efficiency was maximized.

[0074] In this embodiment, in addition to the reason described in the first embodiment described above, there is also an influence of the heat generation difference due to the mechanical difference of the water supply pump 12. The range will have a range.

[0075] As described above, the increase in the specific enthalpy of the feed water is calculated by adding the increase in the specific enthalpy of the feed water by the feed water pump 12, and then the temperature rise ratio is defined, whereby the second embodiment and As in the fourth embodiment, the cycle thermal efficiency can be improved.

[0076] Seventh embodiment

Next, a seventh embodiment of the present invention will be described with reference to FIG.

[0077] In the first embodiment, the third embodiment, and the fifth embodiment, the total number of feed water heaters 6 is 8, and the cycle configuration is such that the temperature rise ratio is 1.9 or more and 3.5 or less. . This is because considering the economy, it is considered that a good number of feed water heaters 6 is 8 in a large thermal power plant.

[0078] In Fig. 1, the extraction from the intermediate pressure turbine 2 includes two places including exhaust, and the extraction from the low pressure turbine 3 includes four places.

[0079] In FIG. 1, the bleed air to the deaerator 9 is medium pressure turbine exhaust bleed 32, but this need not be the case.

When optimization calculation was performed with the number of feed water heaters 6 limited to 8, the cycle thermal efficiency was maximized when the temperature rise ratio was 1.9 or more and 3.5 or less.

[0080] As described above, in the first embodiment, the third embodiment, and the fifth embodiment, the total number of feed water heaters 6 is 8, and the temperature increase ratio is 1.9 or more and 3.5 or less. By adopting such a cycle configuration, the cycle thermal efficiency can be improved as in the first embodiment, the third embodiment, and the fifth embodiment.

[0081] Eighth implementation form

Next, an eighth embodiment of the present invention will be described with reference to FIG.

[0082] In the second embodiment, the fourth embodiment, and the sixth embodiment, feed water heating The total number of vessels 6 is 8, and the cycle composition is such that the specific enthalpy increase ratio is 1.9 or more and 3.5 or less. This is because the number of feed water heaters 6 is considered to be good for large thermal power plants in consideration of economy.

[0083] In Fig. 1, the extraction from the medium pressure turbine 2 includes two places including exhaust, and the extraction from the low pressure turbine 3 takes four places.

[0084] In FIG. 1, the bleed air to the deaerator 9 is medium pressure turbine exhaust bleed 32, but this need not be the case.

The optimization calculation was limited to 8 feedwater heaters 6, and the cycle thermal efficiency was maximized when the specific enthalpy increase ratio was 1.9 or more and 3.5 or less.

[0085] As described above, in the second embodiment, the fourth embodiment, and the sixth embodiment, the total number of the feed water heaters 6 is 8, and the increase ratio of the specific enthalpy is 1.9 or more 3.5. By adopting the cycle configuration as described below, cycle thermal efficiency can be improved as in the second embodiment, the fourth embodiment, and the sixth embodiment.

[0086] Ninth Embodiment

Next, a ninth embodiment of the present invention will be described with reference to FIG. 2, the same parts as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0087] In this embodiment, the total number of feed water heaters 6 in the first embodiment, the third embodiment, and the fifth embodiment described above is increased from eight to nine to nine. The cycle configuration is such that the temperature rise ratio is 1.9 or more and 3.5 or less. Considering economic efficiency, it is considered that eight feed water heaters 6 are good for large thermal power plants, but nine are good as efficiency, power output, and main steam temperature increase. This is because there are cases.

[0088] In Fig. 2, the extraction from the medium pressure turbine 2 includes three places including exhaust, and the extraction from the low pressure turbine 3 is four places, but any number of places may be used as long as there are seven places in total.

In FIG. 2, the bleed air to the deaerator 9 is medium pressure turbine exhaust 32, but this need not be the case. When the optimization calculation was performed by limiting the number of feed water heaters to nine, the cycle thermal efficiency was maximized when the temperature rise ratio was 1.9 or more and 3.5 or less.

[0090] As described above, in this embodiment, the total number of feed water heaters 6 in the first embodiment, the third embodiment, and the fifth embodiment is increased from eight to one. By using a cycle configuration that has nine temperature rise ratios of 1.9 or more and 3.5 or less, Similar to the embodiment, the third embodiment, and the fifth embodiment, the cycle thermal efficiency can be improved.

[0091] Form of the tenth implementation

Next, a tenth embodiment of the present invention will be described with reference to FIG.

[0092] In the present embodiment, the total number of feed water heaters 6 in the second embodiment, the fourth embodiment, and the sixth embodiment described above is increased from eight to nine to nine. The cycle structure is such that the temperature rise ratio is 3.5 or less. Considering economic efficiency, it is said that 8 is a good number of feed water heaters 6 in large thermal power plants. However, as efficiency increases, output increases, and main steam temperature rises, 9 are good. This is because there are cases.

[0093] In Fig. 2, the extraction from the medium pressure turbine 2 includes three places including exhaust, and the extraction from the low pressure turbine 3 is four places.

In FIG. 2, the bleed air to the deaerator 9 is medium pressure turbine exhaust 32, but this need not be the case. When the optimization calculation was performed by limiting the number of feed water heaters to nine, the cycle thermal efficiency was maximized when the specific enthalpy increase ratio was between 1.9 and 3.5.

[0095] As described above, the total number of the feed water heaters 6 in the second embodiment, the fourth embodiment, and the sixth embodiment is increased from 8 to 9, and the ratio is increased. By making the cycle configuration such that the enthalpy increase ratio is 1.9 or more and 3.5 or less, the cycle thermal efficiency can be improved as in the second, fourth, and sixth embodiments. it can.

[0096] Form of Eleventh Implementation

Next, an eleventh embodiment of the present invention will be described with reference to FIGS.

[0097] In the first to tenth embodiments, a cycle configuration is adopted in which the steam temperature at the outlet of the boiler 4 is 600 ° C or higher. This is because the effect becomes more remarkable when the main steam 16 is 600 ° C or higher. The effect of improving the cycle thermal efficiency due to the high temperature of the main steam at 16 temperatures is viable without being impaired by the condition setting of the extracted steam 20.

[0098] In the first to tenth embodiments, by adopting a cycle configuration in which the steam temperature at the outlet of the boiler 4 is 600 ° C or higher, the cycle thermal efficiency is reduced as in the first to tenth embodiments. Can be improved.

Claims

The scope of the claims

[1] A high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by extracted steam generated by the turbine power, a feed water pump, and a condenser, and the working fluid is water In the Rankine cycle, which is a one-stage reheat cycle and a regeneration cycle,

The steam temperature at the boiler outlet is 590 ° C or higher,

The average of the feed water temperature rise in the first feed water heater corresponding to the extraction from the exhaust of the high pressure turbine, and the average feed water temperature rise in the second feed water heater whose feed water is at a lower pressure than the first feed water heater. The steam turbine cycle is characterized by a temperature rise ratio of 1.9 to 3.5.

[2] A high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by the extracted steam of the turbine power, a feed water pump, and a condenser, and the working fluid is water In the Rankine cycle, which is a one-stage reheat cycle and a regeneration cycle,

The steam temperature at the boiler outlet is 590 ° C or higher,

Increase in specific enthalpy of feed water in the first feed water heater corresponding to extraction from the exhaust of the high pressure turbine, and increase in specific enthalpy of feed water in the second feed water heater where the feed water is at a lower pressure than the first feed water heater The steam turbine cycle is characterized by an increase in specific enthalpy of 1.9 to 3.5.

[3] A high-pressure turbine, a reheat turbine, a boiler, a feed water heater that heats feed water to the boiler by the extracted steam of the turbine power, a feed water pump, and a condenser, and the working fluid is water In the Rankine cycle, which is a one-stage reheat cycle and a regeneration cycle,

The steam temperature at the boiler outlet is 590 ° C or higher,

The temperature rise ratio between the rise in feed water temperature in the first feed water heater corresponding to the extraction from the exhaust of the high pressure turbine and the average rise in feed water temperature in the feed water heaters excluding the first feed water heater is 1.9. A steam turbine cycle characterized by being 3.5 or less.

[4] The high-pressure turbine, the reheat turbine, the boiler, and the extracted steam generated by the turbine power In the Rankine cycle, which is equipped with a feed water heater that heats feed water to the boiler, a feed water pump, and a condenser, and is a one-stage reheat cycle in which the working fluid is water and a regeneration cycle,

The steam temperature at the boiler outlet is 590 ° C or higher,

The ratio of the increase in the specific enthalpy of the feed water in the first feed water heater corresponding to the extraction from the exhaust of the high pressure turbine and the average increase in the specific enthalpy of the feed water in the feed water heater excluding the first feed water heater Steam turbine cycle characterized by an enthalpy increase ratio of 1.9 to 3.5.

[5] The steam turbine cycle according to any one of claims 1 and 3, wherein the feed water temperature rise in the second feed water heater is calculated by adding the feed water temperature rise by the feed water pump.

[6] The steam turbine according to claim 2 or 4, wherein the increase in the specific enthalpy of the feed water in the second feed water heater is calculated taking into account the increase in the specific enthalpy of the feed water by the feed water pump. cycle.

[7] The total number of feed water heaters is 8,

6. The steam turbine cycle according to claim 1, wherein the temperature increase ratio is 1.9 or more and 3.5 or less.

[8] The total number of the feed water heaters is 8,

The steam turbine cycle according to any one of claims 2, 4, and 6, wherein the ratio of rise in specific enthalpy is 1.9 or more and 3.5 or less.

[9] The total number of water heaters is nine,

[10] The total number of water heaters is nine;

11. The steam turbine cycle according to any one of claims 1 to 10, wherein the steam temperature at the boiler outlet is 600 ° C or higher.