JPH0610621A - Repowering system of steam power generation facility - Google Patents

Abstract

PURPOSE:To suppress, to the utmost, modification of an already installed steam power generation facility so as to increase a generated electric power amount in the whole of a power station efficiently, and reduce the lowest continuous operation load. CONSTITUTION:In a device in which an exhaust reheating type combined cycle is constituted, an extracted steam turbine plant 40 is provided in a steam power generating facility 1. In the extracted steam turbine plant 40, a part of turbine gas extracted from steam turbine 5, 7, 8 in the steam power generation facility 1 is taken-in as working steam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repowering system for a steam power generation facility, and more particularly to a repowering system for a steam power generation facility capable of increasing the amount of electric power generated by minimizing the modification of an existing steam power generation facility.

[0002]

2. Description of the Related Art A gas turbine plant is additionally installed in an existing steam power generation facility, and the exhaust gas of the gas turbine is used as combustion air for the boiler, while the heat of the exhaust gas from the boiler is used in the steam turbine cycle of the steam power generation facility. System (condensate /
There is known a repowering system in which an exhaust gas reburn type combined cycle is constituted by recovering it to a water supply system). The repowering system for steam power generation equipment has the following major features.

First, by combining an existing power generation plant, the power generation efficiency can be improved.

Secondly, by additionally installing a gas turbine plant, the amount of electric power generated by the entire power plant can be increased.

Thirdly, the repowering system can be constructed in a relatively short period of work because the remodeling portion of the existing steam power generation equipment can be reduced.

On the other hand, the power reserve ratio of each power company is decreasing with the recent significant increase in the power demand, and construction of a power plant is strongly desired in order to cope with the decrease in the power reserve ratio. . However, it is difficult to construct a power plant immediately, and considering this difficulty, the repowering system of a steam power generation facility is one of the effective means to solve the problem of the growth of power demand.

FIG. 7 is a system configuration diagram showing an example of a conventional repowering system of a steam power generation facility that constitutes an exhaust gas reburn type combined cycle.

In the conventional repowering system for steam power generation equipment, a gas turbine 2 is added to a steam turbine plant 1 which is an existing steam power generation equipment.

The existing steam turbine 1 includes a boiler 3, a main steam system 4, a high pressure turbine 5, a turbine reheat system 6, an intermediate pressure turbine 7, a low pressure turbine 8, a condenser 9 and a condensate / water supply system 1.
0 are sequentially connected, and the high-pressure turbine 5, the intermediate-pressure turbine 7, and the low-pressure turbine 8 are driven to rotationally drive the turbine generator 11 to generate electric power and perform work.

While the reheater 13 and the reheat safety valve 14 are installed in the turbine reheat system 6 of the steam turbine plant 1,
The condensate / water supply system 10 includes a condensate pump 16, a multistage low-pressure feed water heater 17 (17a, 17b, 17c), and a deaerator 1.
8. Water supply pump 19 and multi-stage high-pressure water supply heater 2
0 (20a, 20b, 20c) are sequentially installed.

On the other hand, the gas turbine plant 2 additionally installed to the steam turbine plant 1 which is an existing steam power generation facility.
Is composed of a compressor 22, a combustor 23, a gas turbine 24, a gas turbine generator 25, a gas damper 26, and the like.

Since the repowering system of the steam power generation facility uses the exhaust gas from the gas turbine plant 2 as combustion air for the boiler 3 of the steam turbine plant 1, an air preheater is not required. This repowering system lowers the temperature of the exhaust gas through a high pressure stack gas cooler 28 and a low pressure stack gas cooler 29 in order to effectively use the boiler exhaust gas without directly releasing the high temperature exhaust gas from the boiler 3 into the atmosphere from the chimney 27. .

The boiler exhaust gas, which has been cooled by the high-pressure stack gas cooler 28 and the low-pressure stack gas cooler 29 and has a low temperature, removes carbon dioxide gas and the like in the denitration device 30, and then is discharged from the chimney 27 into the atmosphere.

If the temperature of the condensate flowing into the low pressure stack gas cooler 29 is too low, corrosion products due to carbon dioxide gas in the boiler exhaust gas condense on the cooler heat transfer tube surface, impairing reliability, and condensing water. If the temperature is too high, the temperature of the boiler exhaust gas released to the atmosphere becomes high, and the thermal efficiency of the plant is impaired. Therefore, it is necessary to control the temperature of the boiler exhaust gas to be constant.

On the other hand, the condensate temperature depends on the steam turbines 5, 7,
The temperature of the condensate flowing into the low pressure stack gas cooler 29 changes because it changes according to the load of No. 8. In the conventional repowering system, a part of the high temperature feed water at the outlet of the low pressure stack gas cooler 29 is recirculated through the cooler recirculation system 32 and mixed with the condensed water at the inlet side of the low pressure stack gas cooler 29. The cooler recirculation system 32 is provided with a recirculation pump 33 and a flow rate adjusting valve 34. The recirculation flow rate is controlled by controlling the flow rate adjusting valve 34, and the condensate temperature flowing into the low pressure stack gas cooler 29 is controlled. is doing.

In the conventional repowering system of a steam power generation facility, the amount of water supplied to the boiler 3 and the amount of condensed water from the condenser 9 are determined according to the turbine load, but are guided to the condensate / water supply system 10. The amount of water supply is the remaining amount obtained by subtracting the required amount of water supply to the high pressure stack gas cooler 28 and the low pressure stack gas cooler 29 from the amount of water supply to the boiler 3 and the amount of water condensate from the condenser 9.

Therefore, the heat exchange amount in the high-pressure feed water heater 20 and the low-pressure feed water heater 17 arranged in the condensate / water supply system 10 is larger than the heat exchange amount in the normal operation of the steam turbine plant 1. It requires less turbine extraction air.

On the other hand, in the repowering system (combined cycle power plant) of a steam power generation facility, paying attention to the rated load operation of the steam turbines 5, 7, 8 to the feed water heaters 17, 20 of the condensate / feed water system 10. Due to the decrease in the turbine extraction amount, the proportion of steam that flows to the low-pressure side steam turbines 7 and 8 to perform work increases. Therefore, the amount of main steam can be reduced, the load sharing of the high-pressure turbine 5 is reduced, and the load sharing of the intermediate-pressure turbine 7 and the low-pressure turbine 8 is increased instead.

At the same time, the amount of steam extracted to the intermediate-pressure turbine 7 and the low-pressure turbine 8 increases due to the decrease in the amount of steam extracted from the turbine, so that the amount of steam exhausted from the turbine increases and the amount of heat of condensation in the condenser 9 increases. The amount of condensate also increases.

If the amount of steam flowing into the intermediate pressure turbine 7 or the low pressure turbine 8 increases, the design flow rate of the turbine rotor blade may be exceeded, and the blade strength margin may be insufficient.
On the other hand, the inlet pressure or temperature of the turbine vane may rise, and the maximum operating pressure or temperature of each turbine extraction pipe 35a to 35g may be exceeded. Further, a rise in the inlet pressure of the intermediate pressure turbine 7 may cause the reheat safety valve 14 of the turbine reheat system 6 to operate and blow out steam. In such a case, modification such as replacement of turbine moving blades or stationary blades of the steam turbine is required.

Further, when the amount of heat of condensation in the condenser 9 increases, the outlet temperature of the cooling water (seawater) increases in the operation with a constant amount of cooling water, which adversely affects marine life near the discharge port, and the ecosystem. May change. In order to prevent this change, it is necessary to increase the amount of cooling water in the cooling water circulation system 37 by the circulating water pump 36 and suppress the temperature rise of the cooling water (seawater) within the specified value. When the amount of cooling water is increased, the condenser 9 needs to be modified because the cooling water flow rate in the heat exchange tube becomes too large, and the circulating water pump 36 needs to be modified or replaced because the pump capacity is insufficient. Becomes

Further, an increase in the amount of condensed water condensed in the condenser 9 causes a shortage of the capacity of the condensate pump 16 and a condensed water booster pump (not shown), and similar modification or replacement is required.

Next, focusing on the partial load operation of the steam power generation equipment, the steam turbine plant 1 reduces the amount of water flowing through the condensate / water supply system 10 according to the plant load (turbine load), but the gas turbine The gas turbine 24 of the plant 2 is constantly operated at a constant rotation. Therefore, the amount of air compressed by the compressor 22 does not change so much even in the partial load operation, and the amount of boiler exhaust gas discharged from the boiler 3 to the high pressure stack gas cooler 28 and the low pressure stack gas cooler 29 is almost the same as in the rated operation. does not change.

Therefore, despite the partial load operation, the high pressure stack gas cooler 28 and the low pressure stack gas cooler 29 are used.
The amount of water supply required for is not much different from that during rated operation. When the plant load (the load of the turbine or the generator) becomes a certain load or less, most of the water supply / condensate reduced according to the plant load flows to the high pressure stack gas cooler 28 and the low pressure stack gas cooler 29, and the water supply of the condensate water supply system 10 is performed. Heater 17,
The water supply to be guided to 20 will be small. The turbine extraction amount also decreases in proportion to the decrease in the water supply.

On the other hand, due to the reduction of the turbine extraction amount, extraction check valves 39c, 39d, 39e, 39e, 35d installed in the middle of the turbine extraction pipes 35c, 35d, 35e, 35f, 35g.
39f and 39g are slightly opened because the differential pressure across the valve is very small. For this reason, a hunting phenomenon occurs in the bleed check valves 39c, 39d, 39e, 39f, 39g due to fluctuations in the turbine bleed amount, and if the partial load operation is continued for a long period of time, the valve may be damaged. It is necessary to prevent the bleeding check valve from hunting.

The bleed check valves 39c, 39d, 39
e, 39f, 39g have a valve structure that does not cause a hunting phenomenon even if the turbine bleed air has a small flow rate, or, in the case of continuing partial load operation, a minimum continuous operation so that the load operation does not cause a hunting phenomenon. It is necessary to significantly increase the load.

On the other hand, another problem of the partial load operation is that the amount of heat exchanged in the high pressure stack gas cooler 28 does not change so much even though the amount of water supply decreases according to a certain partial load, so that the high pressure stack gas cooler 28 does not change much. There is a risk that steaming will occur in the economizer of the boiler 3 because the water temperature rises too much. Therefore, it is necessary to raise the minimum continuous operation load in the partial load operation.

In the conventional repowering system for steam power generation equipment, there are many points of modification of the existing steam power generation equipment, and the above-mentioned major features of the repowering system are impaired. One of the features of the repowering system is that there are many modifications.
However, the effect of being able to configure the repowering system cannot be exerted in a relatively short period of construction.

On the other hand, overseas, in order to effectively utilize the characteristics of the repowering system for steam power generation equipment, an example in which the output of the steam turbine generator 11 is reduced to a load that can be used without modifying the existing steam power generation equipment However, this partial load operation cannot exert another characteristic of the repowering system. That is, the effect of increasing the amount of electric power generated by the steam power generation facility as a whole will be halved. Considering the increase of electricity demand in Japan,
This operation is not preferable.

Further, in the repowering system of a steam power generation facility, a large increase in the minimum continuous operation load cannot be coped with when the degree of freedom of operation is significantly impaired and the demand for electricity is low at night or on weekends.

The present invention has been made in consideration of the above-mentioned circumstances, and it is possible to effectively increase the amount of electric power generated in the entire power plant by reducing the modification of the existing steam power generation equipment as much as possible and reduce the minimum continuous operation load. The purpose of the present invention is to provide a repowering system for steam power generation equipment.

[0032]

In order to solve the above problems, a repowering system for a steam power generation facility according to the present invention is provided with a gas turbine plant in the steam power generation facility, as set forth in claim 1. The gas turbine exhaust from the gas turbine plant is used as boiler combustion air for steam power generation equipment, while the exhaust gas from the boiler is guided to a high-pressure stack gas cooler and a low-pressure stack gas cooler that heat part of the feed water or condensate. In the repowering system of a steam power generation facility that constitutes a reburn type combined escullet, an extraction steam turbine plant is provided in the steam power generation facility, and this extraction steam turbine plant is a part of the turbine extraction steam from the steam turbine of the steam power generation facility. It was adopted as.

Further, in order to solve the above-mentioned problems, the steam regenerating system for steam power generation equipment according to the present invention is, as described in claim 2, the steam extraction steam turbine plant, in which steam is extracted from a turbine extraction pipe of steam power generation equipment. While the extraction pipe is branched off on the downstream side of the check valve, the downstream side of the extraction steam turbine plant in the previous period is connected to
A downstream side of the condensate pump is connected to a water supply system, and as described in claim 3, the extraction steam turbine plant is provided with a back pressure type steam turbine, and turbine exhaust from the steam turbine is supplied with process steam or heat. After that, a drain tank for collecting condensed drain water is provided, and the downstream side of the drain tank is connected to the condenser of the steam power generation facility or the downstream side of the condensate pump of the condensate / water supply system. As described in claim 4, the extraction steam turbine plant is provided with an extraction condensing steam turbine, and a gas turbine using a cooling medium of a low boiling point medium for condensing turbine exhaust gas and turbine extraction air from the steam turbine as a working fluid. Installed a plant additionally, the latent heat of condensation of the turbine extraction and turbine exhaust from the steam turbine and the retained heat of the boiler exhaust gas of steam power generation equipment While driving the gas turbine plant Te evaporated superheated low-boiling medium, condensate turbine extraction from the steam turbine is one that led to the inlet side of the low pressure stack gas cooler.

Further, in order to solve the above-mentioned problems, the repowering system for steam power generation equipment according to the present invention is
As described in claim 5, a steam turbine plant is provided with a gas turbine plant, and the gas turbine exhaust from this gas turbine plant is used as boiler combustion air for the steam turbine plant, while the exhaust gas from the boiler is supplied or supplied. In a repowering system for steam power generation equipment that configures an exhaust reburning combined isacle by guiding the high pressure stack gas cooler and a low pressure stack gas cooler that heat part of the condensate, a steam turbine plant for reheated steam is installed in the steam power generation equipment. , This steam turbine plant is a part of the reheated steam taken from the turbine reheat system of a steam power generation facility as working steam.

Further, in order to solve the above-mentioned problems, the steam turbine power plant of reheat steam according to the present invention has a repowering system for steam power generation equipment according to the present invention. While having a steam pipe branched from the reheat system, the downstream side of the steam turbine plant of the reheated steam is connected to the condensate / water supply system of the steam power generation facility on the downstream side of the condensate pump, or As described in item 7, the steam turbine plant of reheated steam is
It is equipped with a mixed pressure type steam turbine, and a part of the steam whose pressure has dropped in the middle of the steam turbine of a steam power generation facility is guided to the middle stage of the mixed pressure type steam turbine.

[0036]

According to the repowering system for steam power generation equipment of the present invention, as described in claims 1 to 4, a steam turbine plant is additionally installed in the existing steam power generation equipment (steam turbine plant), and this steam extraction is performed. Since the steam turbine plant takes in turbine bleed air from the existing steam turbine as working steam and drives the steam turbine to generate electricity, the turbine steam extraction amount of the existing steam turbine increases while the steam bleed air of the existing steam turbine is extracted. The amount of steam after the paragraph can be made close to the amount of steam at the time of independent operation of steam power generation equipment at the design flow rate or less, and by suppressing the turbine extraction air to the maximum operating pressure or temperature of the turbine extraction pipe or less, the existing steam turbine No modification is required.

Further, since the condensation heat amount and the condensate amount of the condenser decrease with the reduction of the turbine exhaust amount from the existing steam turbine, the condenser, the circulating water pump, and the condensate pump which constitute the steam power generation facility. No need to modify or replace the condensate booster pump, and existing steam power generation equipment can be used as is. Also, the modification of the existing steam power generation equipment is only required to connect the pipes, so that the period during which the power plant is stopped can be greatly reduced compared to the conventional one.

Since the extraction steam turbine plant is installed in the existing steam power generation facility and the extraction steam turbine plant can also generate electric power, the amount of electric power generated in the entire power plant can be effectively increased.

Further, in the partial load operation of the repowering system of the steam power generation equipment, the amount of steam passing through the extraction check valve of the turbine extraction pipe of the existing steam turbine is the same as that of the conventional repowering system due to the addition of the extraction steam turbine plant. Since the number is larger, the load of chattering of the extraction check valve can be reduced. In the existing steam turbine, the load sharing of the high-pressure turbine is higher than before, and the amount of main steam and the amount of water supply are higher than before, so it is possible to reduce the load that causes steaming in the boiler economizer, and the minimum continuous Driving load can be reduced. Therefore, it becomes possible to follow up even when there is little power demand at night or on weekends, and operability is improved.

Further, the main steam amount of the existing steam turbine is larger than that of the conventional one due to the increase in the load sharing of the high-pressure turbine, and it approaches the main steam amount of the independent operation of the steam power generation facility, so that the throttle loss of the steam control valve is reduced as compared with the conventional one. Thus, the efficiency of the existing steam turbine can be improved.

The repowering system for steam power generation equipment according to the present invention has the following features.
A steam turbine plant of reheated steam was added to the existing steam power generation equipment.This steam turbine plant took in part of the reheated steam from the turbine reheat system of the existing steam power generation equipment as working steam. The steam inflow and the paragraph steam pressure after the medium-pressure turbine of the steam power generation equipment are reduced so that the steam amount is below the turbine design flow rate, the paragraph steam pressure is below the reheat safety valve setting pressure, and the turbine extraction pipe is the maximum. The pressure can be kept below the operating pressure, and there is no need to modify steam power generation equipment. Also, as the turbine exhaust volume decreases, the condenser heat of condensation and the amount of condensate also decrease.
No need to modify or replace circulating water pump, condensate pump and condensate booster pump.

Furthermore, since power is generated in the additionally installed reheat steam steam turbine plant, an electric output can be secured separately from the existing steam power generation equipment, and the amount of power generated by the entire power plant can be effectively increased. be able to.

On the other hand, the load sharing of the medium-pressure turbine and the low-pressure turbine of the existing steam generator is reduced, the load sharing of the high-pressure turbine is higher than that of the conventional repowering system (see FIG. 7), and the main steam amount and hence the water supply amount are large. Therefore, the feed water temperature at the outlet of the high-pressure stack gas cooler can be made lower than before, and the minimum continuous operation load in which steaming does not occur in the boiler economizer can be reduced in partial load operation.

Furthermore, since the main steam amount of the steam turbine in each load of the existing steam power generation equipment is larger than that of the conventional repowering system, the throttle amount in the steam control valve is reduced, and the loss of the throttle is reduced to reduce the existing steam power. The turbine efficiency of the repowering system of the power generation equipment can be improved.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the repowering system for steam power generation equipment according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of a repowering system for steam power generation equipment according to the present invention. In this repowering system, the same members and devices as those in the conventional repowering system shown in FIG.

FIG. 1 shows a steam turbine plant 1 which is an existing steam power generation facility, a gas turbine plant 2 and a second turbine plant.
This is a repowering system for a steam power generation facility in which an extraction steam turbine plant 40 which is a steam turbine plant is additionally installed to configure an exhaust gas reheat type combined cycle.

The steam turbine plant 1 sequentially connects a boiler 3, a main steam system 4, a high pressure turbine 5, a turbine reheat system 6, an intermediate pressure turbine 7, a low pressure turbine 8, a condenser 9 and a condensate / water supply system 10. The high-pressure turbine 5, the intermediate-pressure turbine 7, and the low-pressure turbine 8 are of a single-shaft drive type and are connected by a coupling or the like (not shown).
1 is driven to rotate to generate electricity and work.

The main steam system 4 and the turbine reheat system 6 of the steam turbine plant 1 are provided with steam stop valves 4a, 6a and steam control valves 4b, 6b, while the turbine reheat system 6 has a reheater 14 and A reheat safety valve 14 is installed. Reheat safety valve 4
Reference numeral 2 protects the turbine reheat system 6 by releasing a part of the reheat steam to the outside of the system when the turbine reheat system 6 has an abnormally high pressure.

The condensate / water supply system 10 from the condenser 9 to the boiler 3 includes a condensate pump 16 and a multi-stage low-pressure feed water heater 17.
(17a, 17b, 17c), deaerator 18, feed water pump 19 and multistage high pressure feed water heater 20 (20a, 20)
b, 20c) are sequentially installed. A low pressure gas cooler feed water system 41 is provided so as to bypass the multistage low pressure feed water heater 17 of the condensate / feed water system 10, and a low pressure stack gas cooler 29 and a flow rate control valve 42 are arranged in this water feed system 41. On the other hand, a high pressure stack gas cooler feed water system 43 is provided so as to bypass the multi-stage high pressure feed water heater 20, and a high pressure stack gas cooler 28 is arranged in this feed water system 43.

On the other hand, the gas turbine plant 2 additionally provided to the existing steam turbine plant 1 is composed of a compressor 22, a combustor 23, a gas turbine 24, a gas turbine generator 25, a gas damper 26 and the like. The gas exhaust from the gas turbine plant 2 is used as combustion air for the boiler 3 of the steam turbine plant 1.

The high temperature exhaust gas from the boiler 3 is guided to the boiler exhaust gas system 44. The boiler exhaust gas system 44 includes a high pressure stack gas cooler 28 and a low pressure stack gas cooler 2
9 are sequentially arranged, cooled by the low-pressure stack gas cooler 29, and the temperature of the boiler exhaust gas, which has been lowered in temperature, is removed from the chimney 27 into the atmosphere after removing carbon dioxide gas and the like by the denitration device 30.

The low pressure stack gas cooler 29 has a condenser 9
While the condensed water (condensed water) condensed in is guided, the cooler recirculation system 32 is attached to the low pressure gas cooler water supply system 41 so that the condensed water from the outlet of the low pressure stack gas cooler 29 can be returned to its inlet side. The cooler recirculation system 32 controls the condensate temperature flowing out from the outlet of the low pressure stack gas cooler 29. A recirculation pump 33 and a flow rate control valve 34 are installed in the cooler recirculation system 32.

On the other hand, the turbine extraction pipes 35 (35a to 35g) are taken out from the high-pressure turbine 5, the intermediate-pressure turbine 7, and the low-pressure turbine 8 of the steam turbine plant 1, and the high-pressure turbine 5 and the intermediate-pressure turbine among the turbine extraction pipes 35 are extracted. Turbine extraction pipes 35e, 35f, 35g from 7 are connected to multi-stage high pressure feed water heaters 20 via extraction check valves 39e, 39f, 39g, and supply turbine extraction air for heating feed water to each high pressure feed water heater 20. It is supposed to do. The pipe 35d from the lowermost stage of the intermediate pressure turbine 7 is connected to the deaerator 18 via the check valve 39d.

Further, the turbine extraction pipes 35a, 35b, 35c taken out from the low-pressure turbine 8 are connected to the low-pressure feed water heater 17, and the turbine extraction air is extracted from the low-pressure feed water heater 1 respectively.
We are guiding you to 7. Condensed water (water supply) from the condenser 9 is heated by this turbine extraction air. The extraction check valve 39 is attached to the turbine extraction pipe 35c extracted from the upper side of the turbine extraction pipes 35a, 35b, 35c from the low-pressure turbine 8.
c is installed.

On the other hand, the extraction steam turbine plant 40 additionally installed in the steam turbine plant 1 which is an existing steam power generation facility has an extraction steam of the turbine extraction pipes 35c, 35e; 35f, 35g of the existing steam turbines 5, 7, 8. Check valve 39
c, 39e; 39f, 39g, extraction steam pipes (46 (46a to 46d)) branched from the downstream side are provided, and the steam turbine 48 additionally installed is driven by turbine extraction air guided through each extraction pipe 46. .

Of the extraction pipes 46, the extraction pipe 46a branched from the turbine extraction pipe 35g of the high-pressure turbine 5 functions as the main steam pipe of the additional steam turbine 48 and supplies the main steam to the steam turbine 48. . A steam stop valve 49 and a steam control valve 50 that control the amount of main steam are installed in the extraction pipe 46a. Other extraction pipes 46b, 46c, 46
d is connected to the corresponding intermediate stage of the steam turbine 48 via the check valves 51b, 51c, 51d for backflow prevention and the mixed pressure steam stop valves 52b, 52c, 52d. Check valve 5
1b, 51c and 51d are provided to prevent backflow at the time of transition, and the steam stop valve 49 and the mixed pressure steam stop valves 52b and 52 are provided.
c and 52d are installed to shut off steam when the operation is stopped.

The steam turbine 48 has a turbine generator 54.
Are directly connected to each other, and the steam supplied to the steam turbine 48 rotates the turbine to drive the generator 54 to generate electric power. The steam that has worked in the steam turbine 48 is guided to the condenser 55, where it is cooled and becomes condensed water. In the condenser 55, in addition to cooling the steam that has worked in the steam turbine 48 with seawater, cooling with fresh water such as air cooling or cooling tower is selected in consideration of the installation space and the recirculation measures. The internal pressure of the condenser 55 is not only atmospheric pressure,
A steam ejector or a vacuum pump (both not shown) can be maintained at a negative pressure to improve turbine efficiency.

The condensate condensed in the condenser 55 is connected to the downstream side of the condensate pump 16 of the condensate / water supply system 10 via a condensate pipe 56. The condensate pipe 56 is provided with a condensate pump 57 and an adjusting valve 58 for adjusting the amount of condensed water. The control valve 58 keeps the condensate level in the condenser 55 constant.

By the way, the extraction steam turbine plant 40
The turbine load of the steam turbine can be adjusted by controlling the main steam (turbine extraction air) guided to the extraction pipe 46a by the steam control valve 50.

The steam to the additionally installed steam turbine 48 is sequentially branched and introduced from the high pressure side turbine bleed air of the steam power generation facility, and is used as the main steam and the mixed pressure steam in the middle stage. The additional steam turbine 48 is designed in the middle paragraph so as to match the pressure of the mixed pressure steam, and the mixed steam amount depends on the extraction pressure of the existing steam turbines 5, 7, and 8 and the paragraph pressure of the additional steam turbine 48. It is not necessary to adjust it because it is determined by the pressure difference in balance. The turbine load of the additional steam turbine 48 can be adjusted by controlling only the main steam with the steam control valve 50.

Next, driving, rated operation and partial load operation of the repowering system of the steam power generation facility will be described.

When the repowering system is started up, the steam turbine plant 1 which is an existing steam power generation facility is started up, and after the turbine extraction pressure of the existing steam turbines 5, 7, 8 is stabilized, the additional extraction steam turbine plant 40 is installed.
Of the mixed pressure steam stop valves 52b, 52c, 52d while controlling the turbine load of the steam turbine 48 with the steam control valve 50 by opening the main steam stop valve 49 for supplying the main steam (high-pressure side turbine extraction air) to the steam turbine 48 of FIG. Sequentially open from the high pressure side.

The main steam stop valve 49 and the mixed pressure steam stop valve 5
The steam turbine 48 of the extraction steam turbine plant 40 is started by opening 2b, 52c, and 52d, and the rated operation is started with the passage of time.

At the time of rated operation, the turbine extraction pipes 35g, 35 of the steam turbines 5, 7, 8 of the existing steam generator are installed.
Turbine extraction air extracted from f, 35e, 35c is guided to the additional extraction steam turbine plant 40 branched from the downstream side of the extraction check valves 39g, 39f, 39e, 39c and introduced into the steam turbine 48. The steam turbine 48 installed additionally works by the steam extracted from the turbine to drive the generator 54.

The amount of turbine extracted air from the existing steam turbines 5, 7, 8 is determined by the feed water heaters 17, 2 of the condensate / feed water system 10.
The sum of the amount of extracted air to 0 and the amount of extracted air to the additionally installed steam turbine 48, and the amount of steam after the extraction stage of the existing steam turbines 5, 7 and 8 is the rated load of the conventional repowering system shown in FIG. 7. The amount is smaller than that during operation, and can approach the rated steam amount during independent operation of the existing steam turbine plant 1.

This repowering system can be set to the design flow rate of the existing steam power generation equipment or less, and the pressure and temperature of the turbine extraction air can be set to the maximum operating pressure or temperature of the turbine extraction pipe or less. No modification of the steam turbine plant 1 is required, and the conventional steam turbine plant can be used as it is.

Further, since the turbine exhaust amount exhausted from the existing steam turbines 5, 7, 8 to the condenser 9 is smaller than the conventional one, the condensation heat amount in the condenser 9 is reduced and the cooling water amount is increased. Since it is not necessary to make it necessary, the condenser 9 and the circulating water pump 36 for circulating the cooling water to the condenser 9 do not need to be modified.

On the other hand, even if the amount of condensed water in the condenser 9 decreases,
In the condensate / water supply system 10 of this steam turbine plant 1,
The extraction steam turbine plant 4 is provided downstream of the condensate pump 16.
Since the condensate from the condenser 55 of 0 is introduced, the amount of condensate passing through the condensate pump 16 can be made equal to or less than the designed flow rate, and the condensate pump need not be modified.

By the way, during partial load operation of the repowering system, the turbine extraction pressure from the existing steam turbines 5, 7, 8 decreases, but in this case, the load of the steam turbine 48 of the additional extraction steam turbine plant 40 is already installed. Since the main steam amount due to the throttle of the steam control valve 4b is reduced by decreasing it according to the steam turbine load, the turbine stage pressure of the additionally installed steam turbine 48 is also reduced, and the mixed pressure steam amount is balanced.

During this partial load operation, the turbine extraction amount from the existing steam turbines 5, 7 and 8 becomes larger than the turbine extraction amount of the conventional repowering system. However, in the repowering system shown in FIG. , 7 and 8 from the turbine extraction air extraction check valve 39g, 3
9f, 39e, 39c is branched from the downstream side and guided to the additional extraction steam turbine plant 40, so the turbine extraction amount (passing steam amount) passing through the extraction check valves 39g, 39f, 39e, 39c is This is more than the partial load operation of conventional repowering systems. Therefore, the bleed check valve 3
It is possible to prevent the chattering phenomenon from occurring in 9g, 39f, 39e, and 39c, and it is possible to reduce the plant load of the existing steam turbine plant 1.

Further, the main steam amount of the existing steam turbine plant 1 increases from the partial load operation of the conventional repowering system, and approaches the partial load operation of the existing steam turbine plant 1 in the independent operation. A coal economizer (not shown) can reduce the plant load where steaming occurs.

FIG. 2 shows a second embodiment of the repowering system for steam power generation equipment according to the present invention.

In the repowering system for steam power generation equipment shown in this embodiment, a back pressure type steam turbine 60 is adopted in the extraction steam turbine plant 40A additionally installed in the steam turbine plant 1 which is an existing steam power generation equipment. Since other configurations are not different from those of the repowering system shown in FIG. 1, the same reference numerals are given and description thereof will be omitted.

Additional extraction steam turbine plant 40A
Uses the steam turbine 60 as a back pressure type and does not additionally install a condenser, and uses turbine exhaust steam from the steam turbine 60 as process steam or heat supply steam outside the system 61.
The high temperature drain water condensed and collected by the equipment 61 outside the system is collected in the drain tank 62.

The high temperature drain water collected in the drain tank 62 is introduced into the condenser 9 or the downstream side of the condensate pump 16 of the condensate / water supply system 10 through the condensate pipes 63a and 63b. One condensing pipe 63a is provided with an adjusting valve 64 for adjusting the level of the drain water in the drain tank 62. The adjusting valve 64 adjusts the level in the drain tank 62 to be constant while the condenser 9 Have been collected. The other condensate pipe 63b is provided with a condensate pump 65 and a flow rate adjusting valve 66, and the valve control of the flow rate adjusting valve 66 regulates the amount of condensate supplied to the low pressure gas cooler feed system 41.

The low pressure gas cooler feed water system 41 is provided with a flow rate control valve 67 on the inlet side of the low pressure stack gas cooler 29, which is valve-controlled by the outlet side feed water temperature.

The steam turbine repowering system shown in FIG. 2 is used as an additional extraction steam turbine plant 40.
No condenser or attached cooling equipment is required for A, and a compact drain tank 62 is used instead, so the installation space is small.

Further, the high temperature drain water of, for example, about 100 ° C. stored in the drain tank 62 is supplied to the low pressure gas cooler feed water system 41 for mixing, while the condensate supplied to the low pressure stack gas cooler 29 by the flow control valve 66. The temperature of (water supply) is controlled to be constant, for example, about 80 ° C. Since the condensate temperature supplied to the low pressure stack gas cooler 29 can be controlled by the drain water from the drain tank 62, it is not necessary to install a cooler recirculation system.

On the other hand, the steam turbine plant 4 additionally installed
Since the 0 A steam turbine 60 is of a back pressure type, the effective heat drop is small, and the back pressure type steam turbine 60 has a smaller output than the condensing type steam turbine of FIG. 1.

FIG. 3 shows a third embodiment of the repowering system for steam power generation equipment according to the present invention.

In the repowering system for steam power generation equipment shown in this embodiment, the extraction steam turbine plant 40B is installed in the steam turbine plant 1 as an existing steam power generation equipment.
While installing this extraction steam turbine plant 40B
Gas turbine plant using low boiling point medium as working fluid
0 is added. Other configurations are substantially the same as the configuration of the repowering system shown in FIG. 1 except for the low-pressure gas cooler supply system 71, and therefore, the same reference numerals are given and description thereof is omitted.

In the extraction steam plant 40B additionally installed,
The extraction check valves 39g, 39f, 39e of the turbine extraction pipes 35g, 35f, 35e of the high-pressure turbine 5 and the intermediate-pressure turbine 7 of the existing steam generator are provided with extraction pipes 46a, 46b, 46c branched from the downstream side, and the extraction air is extracted. Piping 46a
46c is a steam turbine 72 as an extraction / condensation turbine
On the other hand, a first condenser 73 that cools and condenses the turbine exhaust of the steam turbine 71 and a second condenser 74 that cools and condenses the turbine bleed air in the low pressure stage are installed. The condensate temperature condensed in the second condenser 74 becomes constant because it becomes the saturation temperature of the turbine extraction pressure. For this reason,
Condensate from the second condenser 74 is suitable for being introduced into the low pressure stack gas cooler 29 as condensate.

On the other hand, the condensate pipe 75 from the first condenser 73 is connected to the condenser 9 of the existing steam power generation facility via a control valve 76 provided midway. The internal pressure of the first condenser 73 is adjusted by the control valve 76.

The condensate pipe 77 cooled and condensed by the second condenser 74 constitutes a low pressure gas cooler water supply system 71, and a low pressure stack is provided midway through a condensate pump 78 and a flow control valve 79. It is connected to the gas cooler 29. The amount of condensed water is adjusted by the flow rate control valve 79 so that the temperature of the condensed water flowing out from the low pressure stack gas cooler 29 becomes a predetermined temperature.

The cooling system of the first condenser 73 and the second condenser 74 is constructed as a part of the additionally installed gas turbine plant 70. In this gas turbine plant 70, a low boiling point medium having a lower boiling point than water is used as a working fluid as a cooling medium, and the low boiling point medium is steam (turbine) in a first condenser 73 and a second condenser 74 having a multi-stage structure. It is heated by the latent heat of exhaust gas and turbine bleed air and evaporated. The evaporated low boiling point medium is superheated in the superheater 80 by the heat retained in the boiler exhaust gas.

The low-boiling-point medium superheated by the superheater 80 is guided to the additional gas turbine 81 to be rotationally driven, and the turbine generator 82 is driven to be used for power generation. The loads on the gas turbine 81 and the generator 82 are determined by controlling the flow rate of the low boiling point medium with the regulator valve 83 so that the boiler exhaust gas temperature at the outlet of the superheater 80 becomes a predetermined gas temperature. Reference numeral 84 is a stop valve.

The low-boiling-point medium that has worked in the gas turbine 81 and expanded to have a low pressure / temperature is condensed in the condenser 84, then pressure-increased by the pressure increasing pump 86 and sent to the first condenser 73. , Constitutes a closed cycle. In this way, the gas turbine plant 70 using a low boiling point medium as a working fluid is additionally installed in the additional extraction steam turbine plant 40B.

By additionally installing the gas turbine plant 70 using a low boiling point medium as a working fluid, it is possible to effectively utilize the steam latent heat of turbine exhaust and bleed air and the retained heat of boiler exhaust gas for power generation. It is possible to increase the amount of power generated.

When the gas turbine plant 70 is added to the extraction steam plant 40B, the steam turbine 72 and the gas turbine 80 are directly connected to each other to form a single-shaft type.
The generator 82 for the gas turbine 80 is no longer required, and it is possible to reduce the size and the mechanical loss.

In the steam turbine power plant repowering system shown in FIG. 3, the steam extracted from the steam turbine 72 of the additionally installed steam extraction turbine plant 40B is used for condensate to be supplied to the low pressure stack gas cooler 29.
Since the pipe for branching the condensate from the condensate / water supply system 10 is unnecessary, the entire amount of condensate condensed in the condenser 9 of the existing steam turbine plant 1 can be flowed to the low-pressure feed water heater 17,
The required turbine extraction amount is not so different from that during the stand-alone operation of the existing steam turbine plant 1. Therefore, the extraction pipe for extracting the extracted steam from the low-pressure turbine 8 to the extracted steam turbine plant 40B is unnecessary. The plant shutdown period will be further shortened because the piping work for extraction piping will not be required.

Furthermore, since the condensate temperature supplied to the low pressure stack gas cooler 29 can be made constant, the cooler recirculation system is not required as in the repowering system shown in FIG.

FIG. 4 shows a fourth embodiment of the repowering system for a steam power plant according to the present invention.

The repowering system shown in this embodiment is shown in FIG. 1 in that the steam turbine plant 90 additionally installed in the steam turbine plant 1 which is an existing steam generator is driven by reheated steam. Basically, the repowering system is different from the repowering system, and the other configurations are substantially the same, and therefore the same reference numerals are used for description.

The repowering system of the steam power generation facility shown in FIG. 4 is obtained by adding a steam turbine plant 90 for reheated steam to the existing steam turbine plant 1. The steam turbine plant 90 for reheated steam is already installed. Has a steam pipe 91 branched from the high temperature reheat pipe 6c of the turbine reheat system 6 of the steam turbine plant 1 of FIG. 1, and the steam pipe 91 is additionally installed via a steam stop valve 92 and a steam control valve 93. Connected to. A turbine generator 95 is directly connected to the steam turbine 94, and the steam turbine 94 is driven to drive the generator 95 for power generation.

The steam that has worked in the steam turbine 94 and expanded is guided to the condenser 96, where it is condensed to be condensed water. The condensate is boosted by the condensate pump 97 and introduced into the condensate / water supply system 10 of the existing steam turbine plant 1 through the condensate pipe 98 on the downstream side of the condensate pump 16. The condensate pipe 98 is provided with a flow rate control valve 99 for adjusting the amount of condensed water.

By the way, in the additionally installed steam turbine plant 90 for reheated steam, a steam pipe 91 branched from the downstream side of the reheater 13 of the turbine reheat system 6 of the existing steam power generation facility.
The reheated steam is guided through the steam control valve 93 so that the pressure of the high temperature reheated steam pipe 6c, that is, the inlet pressure of the intermediate pressure turbine 7 becomes a set pressure according to the load.
Is adjusted at.

In general, the reheat steam valves 6a and 6b are fully opened during operation, and the inlet pressure changes substantially in proportion to the amount of steam flowing into the intermediate pressure turbine 7. Therefore,
Since the high-temperature reheat steam pressure and the amount of steam entering the intermediate-pressure turbine are substantially proportional to each other, the amount of steam flowing into the intermediate-pressure turbine 7 can be controlled by controlling the high-temperature reheat steam pressure with the steam control valve 93.

Further, by directly controlling the high temperature reheat vapor pressure, even if the reheat pressure rises under a high load, it can be easily suppressed to a pressure equal to or lower than the pressure at which the reheat safety valve 14 operates.

One of the steams separated from the high-temperature reheat steam pipe 6c is worked in the existing medium-pressure turbine 7 and low-pressure turbine 8 and then condensed in the existing condenser 9 to become condensate. The pressure is increased at 16 and is guided to the low pressure feed water heater 17 or the low pressure stack gas cooler 29. Also, the other reheated steam, after working in the additional steam turbine 94,
Condensed water is condensed in the attached condenser 96 to form condensed water, and the condensed water pump 9
The pressure is increased at 7, and the downstream side of the existing condensate pump 16 is joined and collected.

Additional reheat steam steam turbine plant 9
The condenser 96 installed at 0 can be freely selected according to the installation space, environmental measures, etc., such as seawater, air or fresh water cooled by a cooling tower as a cooling medium. Further, the internal pressure of the condenser 96 can be set to a negative pressure by an atmospheric pressure steam ejector, a vacuum pump or the like to improve the turbine thermal efficiency. At this time, the amount of condensate is adjusted by the condensate flow control valve 99 so that the condensate level of the condenser 96 is kept constant.

Focusing on the rated load operation of the steam turbines 5, 7, 8 and the generator 11 of the steam turbine plant 1 which is an existing steam power generation facility, the existing steam turbine plant 1
Since a part of the steam flows out from the high temperature reheat steam pipe 6c of the turbine reheat system 6 to the additionally installed steam turbine plant 90, the amount of steam flowing into the existing medium-pressure turbine 7 or low-pressure turbine 8 is the same as that of the conventional repowering system. Although it will decrease further, the amount of main steam to the high-pressure turbine 5 increases, and the existing steam turbines 5, 7, 8 balance in a state close to islanding.

Further, since the turbine exhaust amount from the existing steam turbines 5, 7, 8 is also reduced, the condensation heat amount and condensed water amount of the condenser 9 are also reduced as compared with the conventional repowering system.
Therefore, the amount of steam flowing into the existing intermediate-pressure turbine 7 is controlled by the steam control valve 93 based on the set value of the high temperature reheat pressure, so that the existing steam turbine equipment 3, 4, 5,
The rated load operation can be performed without modifying the 6, 7, and 8, the reheat safety valve 14, the condenser 9, the circulating water pump 36, the condensate pump 16, and the condensate booster pump (not shown).

Further, the steam turbine 94 of the steam turbine plant 90 for branching the reheat steam from the turbine reheat system 6 is used.
The steam that has flowed into expands and performs work to generate power from the turbine generator 95 that is directly connected, so that the amount of power generated in the entire power plant can be increased.

Next, paying attention to the partial load operation of the steam power generation equipment, as in the rated load operation, a part of the reheated steam is fed from the high temperature reheated steam pipe 6c to the steam turbine plant 90 of the reheated steam.
By guiding to the high pressure turbine 5, the main steam amount to the high-pressure turbine 5 can be increased more than the main steam amount under the same load of the conventional repowering system, so that the feed water amount is also increased, and accordingly, the high pressure stack gas cooler 28. It is possible to lower the outlet feed water temperature, and it is possible to reduce the minimum continuous operation load in which the feed water does not steam in the economizer of the boiler 3.

Further, in the repowering system of the steam power generation facility, the main steam amount in the load of the existing steam turbines 5, 7, 8 and the generator 11 is larger than the main steam amount in the same load in the conventional repowering system. Therefore, the throttle loss can be reduced by increasing the valve opening of the main steam control valve.

FIG. 5 shows a repowering system for steam power generation equipment according to a fifth embodiment of the present invention.

The repowering system for steam power generation equipment shown in this embodiment is provided in the steam turbine plant 90A for reheated steam additionally installed in the existing steam turbine plant 1.
The steam pipe 101 is branched from the crossover pipe 100 from the existing medium-pressure turbine 7 to the low-pressure turbine 8, and the steam pipe 101 is guided to a middle stage of the additional steam turbine 102. Since the repowering system shown in FIG. 4 is not different from the repowering system shown in FIG. A steam check valve 1 for preventing backflow is provided on the steam pipe 101.
03 and steam stop valve 104 are installed.

In this repowering system for steam power generation equipment, a part of the steam flows out from the crossover pipe 100 of the existing steam turbine plant 1 to the additional steam turbine 102. Therefore, the amount of steam flowing into the low pressure turbine 8 is as shown in FIG. The repowering system shown in FIG. 4 can be reduced, and the operating state of the low-pressure turbine 8 approaches the state of the existing steam turbine plant operating alone, and approaches the operation with optimum efficiency.

Further, since the load on the low pressure turbine 8 is reduced,
Since the load of the high-pressure turbine 5 increases, the amount of main steam to the existing steam turbine increases from the repowering system shown in FIG. 4 under the same load, so the amount of water supply also increases and the outlet water supply temperature of the high-pressure stack gas cooler 28 increases. Can be lowered. Therefore, it is possible to further reduce the minimum continuous operation load in which steaming does not occur in the economizer of the boiler 3 in the partial load operation. At the same time, the opening of the steam control valve 93 can be made larger than the same load in the case of the repowering system of FIG. 4 by the increase of the main steam amount, so that the throttling loss can be further reduced.

Reheated steam turbine plant 90 additionally installed
In A, the steam turbine 102 is designed as a mixed pressure turbine so that the pressure of mixed pressure steam can be introduced so that low pressure steam can be introduced, and the amount of mixed pressure steam is equal to the pressure of the crossover pipe 100 of the existing steam turbine. Additional steam turbine 10
Since it is determined in balance by the pressure difference of the introduction pressure of No. 2, it is not necessary to adjust, and only the main steam amount is the steam control valve
It should be controlled by.

The mixed steam is steam turbine 102.
Since it is expanded inside and used for power generation, the output of the additional steam turbine and generator can be made larger than that of the example of the repowering system shown in Fig. 4, and the amount of power generated by the entire power plant can be further increased. You can

FIG. 6 shows a sixth embodiment of the repowering system for steam power generation equipment.

The repowering system shown in this embodiment is a steam turbine plant 90 for reheated steam additionally installed in the steam turbine plant 1 which is an existing steam power generation facility.
B is configured to guide the turbine bleed air from the intermediate pressure turbine 7 and the low pressure turbine 8. Since other configurations are not different from those of the repowering system shown in FIG. 4, the same reference numerals are given and description thereof will be omitted.

In the repowering system of the steam power generation facility, the extraction pipes 106a and 106b are connected to the turbine section in the middle of the steam turbine 105 provided in the steam turbine plant 90B for reheated steam. The extraction pipes 106a and 106b are turbine extraction pipes 35e and 35c taken out from the intermediate pressure turbine 7 and the low pressure turbine 8, respectively.
Is branched from the downstream side of the extraction check valves 39e and 39c, and these turbine extractions are used as a mixed pressure steam source of the steam turbine 105. Check valves 107a, 107b and steam stop valves 108a, 108b for preventing backflow are provided in the extraction pipes 106a, 106b.

Steam turbine plant 90 for this reheated steam
In B, the amount of steam in the medium-pressure turbine 7 and the low-pressure turbine 8 after the turbine extraction stage, which is the mixed pressure steam source of the steam turbine 105, is smaller than that in the repowering system shown in FIG. Produce an effect.

The extraction pipes 106a and 106b are connected to the extraction check valves 39e and 39 of the turbine extraction pipes 35e and 35c, respectively.
Since it is branched from the downstream side of c, the bleed check valve 39
The turbine extraction amount passing through e and 39c can be made larger than the turbine extraction amount shown in FIGS. 5 and 6 under the same load. Therefore, the differential pressure across the bleed check valves 39e, 39c can be increased, and at partial load,
It is possible to prevent chattering of the bleed check valve due to a decrease in the turbine bleed amount.

In the partial load operation of the repowering system for the steam power generation facility of this embodiment, the extraction check valves 39f, 39g, 39e and 39c which may cause chattering due to the decrease in turbine extraction amount are Since the extraction pressure of the extraction check valves 39f and 39g is higher than the main steam pressure of the additional steam turbine, it cannot be used as mixed pressure steam. To prevent chattering of the bleed check valves 39f, 39g, bypass the water supply by using the water supply bypass lines (not shown) of the high-pressure water supply heaters 20c, 20b.
It is possible if the turbine bleed air is cut (bleed air amount 0).

Further, the chattering prevention of the extraction check valve in the partial load operation also contributes to the lowering of the minimum continuous operation part.

In the repowering system of the steam power generation facility of the present invention, each embodiment in which the extraction steam turbine plant or the reheated steam turbine plant is added to the existing repowering system has been described, but the spirit of the present invention is described. Various modifications can be made without departing from the above.

[0121]

As described above, the repowering system for a steam power generation facility according to the present invention is a system equipped with an exhaust gas reburn type combined escullet, in which a steam extraction steam turbine plant is provided in the steam power generation facility. Since the plant has taken in a part of the turbine extraction air from the steam turbine of the steam power generation facility as working steam, it is possible to reduce the turbine displacement of the existing steam turbine,
As the amount of condensation heat and condensate in the condenser decreases with this decrease, repowering should be performed without modifying the existing steam turbine, condenser, circulating water pump, condensate pump, condensate booster pump, etc. Therefore, even if the extraction steam turbine plant is additionally installed, the period during which the repowering system is stopped can be significantly shortened. In addition, the additional extraction steam turbine plant can also generate power, which can effectively increase the amount of power generated by the entire power plant. It is possible to effectively increase the amount of generated electric power.

Further, since the steam pipe of the extraction steam turbine plant is branched from the downstream side of the extraction check valve of the extraction steam turbine of the turbine extracted from the steam turbine of the existing steam power generation facility, the turbine extraction amount passing through the extraction check valve. While it is possible to effectively prevent chattering from occurring in the extraction check valve, the condensate that has worked in the extraction steam turbine plant is returned to the condensate / water supply system of the steam power generation facility. Therefore, it is possible to secure a sufficient amount of water supply to the boiler, prevent steaming from occurring in the boiler's economizer, reduce the minimum continuous operation load, and elastically operate the repowering system. Can be done
Operability is improved.

Furthermore, since the amount of main steam supplied to the steam turbine of the existing steam generator is increased, the throttle loss of the steam control valve can be reduced, and the efficiency of the existing steam turbine is improved.

On the other hand, the repowering system for steam power generation equipment according to the present invention as defined in any one of claims 5 to 7 is a system equipped with an exhaust gas reheat type combined cycle, and the steam turbine plant of reheated steam is installed in the steam power generation equipment. Since this steam turbine plant takes in a part of the reheated steam from the turbine reburning system of the steam power generation facility as working steam, it is possible to reduce the turbine displacement of the existing steam turbine. Since repowering can be achieved without modifying the water tank, circulating water pump, condensate pump, condensate booster pump, etc., the repowering system suspension period can be significantly reduced compared to the conventional repowering system, while additional bleed air is added. Since the steam turbine plant also generates electricity, it is possible to increase the amount of electricity generated by the entire power plant effectively. It can do.

Further, since the condensate working in the extraction steam turbine plant is joined to the condensate / water supply system of the steam power generation facility, the amount of water supplied to the boiler can be increased more than that of the conventional repowering system, and therefore the boiler can be increased. The minimum continuous operation load that does not cause steaming in the economizer can be reduced, improving operability.

Further, since the amount of main steam of the steam power generation equipment is larger than that of the conventional repowering system, the throttle loss of the steam control valve can be reduced and the efficiency of the existing steam turbine is improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of a repowering system for a steam power generation facility according to the present invention.

FIG. 2 is a system configuration diagram showing a second embodiment of a repowering system for a steam power generation facility according to the present invention.

FIG. 3 is a system configuration diagram showing a third embodiment of a repowering system for a steam power generation facility according to the present invention.

FIG. 4 is a system configuration diagram showing a fourth embodiment of a repowering system for a steam power generation facility according to the present invention.

FIG. 5 is a system configuration diagram showing a fifth embodiment of the repowering system for a steam power generation facility according to the present invention.

FIG. 6 is a system configuration diagram showing a sixth embodiment of a repowering system for a steam power generation facility according to the present invention.

FIG. 7 is a system configuration diagram showing a conventional repowering system for steam power generation equipment.

[Explanation of symbols]

1 Steam power generation facility (steam turbine plant) 2 Gas turbine plant 3 Boiler 4 Main steam system 5 High pressure turbine (steam turbine) 6 Turbine reheat system 7 Medium pressure turbine (steam turbine) 8 Low pressure turbine (steam turbine) 9 Condenser 10 Condensate / Water Supply System 11 Generator 16 Condensate Pump 17 (17a to 17c) Low Pressure Water Heater 20 (20a to 20c) High Pressure Water Heater 22 Compressor 23 Combustor 24 Gas Turbine 25 Generator 27 Chimney 28 High Pressure Stack Gas cooler 29 Low pressure stack gas cooler 30 Denitration device 32 Cooler recirculation system 35 (35a to 35g) Turbine extraction pipe 39 (39c, 39e, 39f, 39g) Extraction check valve 40, 40A, 40B Extraction steam turbine plant 41, 71 Low pressure gas cooler Water supply system 43 High pressure gas cooler Water supply system 44 Bo La Exhaust gas system 46 (46a, 46b, 46c, 46d) Extraction piping 48 Steam turbine 54 Turbine generator 55 Condenser 62 Drain tank 70 Gas turbine plant 72 Extraction condensate turbine 73 First condenser 74 Second condenser 80 Superheater 81 Gas Turbine 82 Generator 85 Condenser 90, 90A, 90B Reheat Steam Steam Turbine Plant 91 Steam Pipe 94 Steam Turbine 95 Turbine Generator 96 Condenser 100 Crossover Pipe 102, 105 Steam Turbine 106a, 106b Bleed pipe

Claims (7)

[Claims] 1. A steam turbine power generation facility is provided with a gas turbine plant, and the gas turbine exhaust from this gas turbine plant is used as boiler combustion air for the steam power generation facility, while the exhaust gas from the boiler is supplied or condensed. In the repowering system of a steam power generation facility that guides the high pressure stack gas cooler and the low pressure stack gas cooler that heat the parts, and configures an exhaust reburning combined isacle, in the steam power generation facility, an extraction steam turbine plant is installed, and this extraction steam turbine plant is A repowering system for steam power generation equipment, wherein a part of turbine extraction air is taken in as steam from the steam turbine of the steam power generation equipment. 2. The extraction steam turbine plant is provided with an extraction pipe branched from a turbine extraction pipe of the steam power generation facility on a downstream side of the extraction check valve, while the downstream side of the extraction steam turbine plant of the previous period is connected to the steam generation facility. The repowering system for steam power generation equipment according to claim 1, wherein the repowering system is connected to the condensate / water supply system on the downstream side of the condensate pump. 3. An extraction steam turbine plant is provided with a back pressure type steam turbine, and a drain tank for recovering condensed drain water is provided after utilizing a turbine exhaust from the steam turbine for process steam or heat supply. The repowering system for steam power generation equipment according to claim 1, wherein the downstream side of the steam power generation equipment is connected to the downstream side of the condenser of the steam power generation equipment or the condensate pump of the condensate / water supply system. 4. An extraction steam turbine plant is provided with an extraction condensate steam turbine, and a gas turbine plant is additionally provided with a cooling medium of a low boiling point medium for condensing turbine exhaust gas and turbine extraction air from this steam turbine as a working fluid. Then, the low boiling point medium is evaporated and overheated by the turbine extraction air from the steam turbine and the latent heat of condensation of the turbine exhaust and the heat of the boiler exhaust gas of the steam power generation facility to drive the gas turbine plant, while the turbine from the steam turbine is used. The repowering system for steam power generation facilities is characterized in that the bleed water condensate is led to the inlet side of the low-pressure stack gas cooler. 5. A steam turbine power generation facility is provided with a gas turbine plant, and the gas turbine exhaust from this gas turbine plant is used as boiler combustion air for the steam power generation facility, while the exhaust gas from the boiler is used as feed water or condensate water. In a repowering system of a steam power generation facility that guides the high-pressure stack gas cooler and the low-pressure stack gas cooler that heat a part of the steam turbine, the steam turbine plant for reheat steam is installed in the steam power generation facility. The plant is a repowering system for steam power generation equipment, characterized by taking in part of the reheated steam from the turbine reheat system of steam power generation equipment as working steam. 6. A steam turbine plant of reheated steam is provided with a steam pipe branched from a turbine reheat system of a steam power generation facility, while a downstream side of the steam turbine plant of reheated steam is connected to the steam turbine plant of the steam power generation facility. The repowering system for steam power generation equipment according to claim 5, wherein the repowering system is connected to the condensate / water supply system on the downstream side of the condensate pump. 7. A steam turbine plant of reheated steam is provided with a mixed pressure type steam turbine so that a part of the steam whose pressure has dropped in the steam turbine of the steam power generation facility is guided to a middle stage of the mixed pressure type steam turbine. The repowering system for steam power generation equipment according to claim 5.