JPS5823207A - Thermoelectric power plant equipped with stored steam power generation system - Google Patents

Abstract

PURPOSE:To reduce the loss of the heat quantity of steam and obtain a highly-effective turbine by installing a regenerative heat exchanger between a boiler and a heat accumulator and storing the heat of the steam fed into the heat accumulator and heating the steam supplied into a turbine for peak load with the regenerated heat. CONSTITUTION:When the load for a main power generation system A is low at night, a regenerative heat-steam bleeding valve 14 and a gate valve 19 are opened, and a gate valve 22 and a steam regulating valve 24 are closed. The steam which is reheated to high temperature in a reheater 3 passes through the bleed valve 14 and a regenerative heat exchanger 31, and performs heat-exchange with a regenerative heat medium, and passes through the gate valve 19 and is stored as hot water in a heat accumulator 16. When the load in the main power generation system A is exceeded, owing to the increase of the demand of electric power, the bleed valve 14 and the gate valve 19 are closed, and the gate valve 22 and the regulating valve 24 are controlled, to the open side then the hot-water in the heat accumulator 16 is converted to steam, which receives heat from the regenerative heat medium, during passing through the regenerative heat exchanger 31, and is converted to the excessively heated steam, which flows into a turbine 17 for peak load. Then, a power generator 25 for peak load is driven to generate electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal power plant having a steam storage power generation system that combines a heat storage device and a peak power generation unit.

In recent years, the demand for electricity has been on the rise, with much demand occurring during the day and relatively little demand at night. Therefore, as a method to deal with this uneven demand between day and night, steam storage power generation that combines a heat storage device and a peak power generation unit has been proposed. In other words, the above-mentioned steam storage power generation involves extracting steam from a thermal power generation unit at night when electricity demand is low and storing 70 thermal energy in a heat storage device.
This is a power generation method that uses the stored thermal energy to generate steam during the daytime, when electricity demand is high, and uses that steam to drive a peak-use turbine to generate electricity, meeting the day and night electricity demand. This is one powerful method.

That is, FIG. 1 is a system diagram of a thermal power plant having the above-mentioned steam storage power generation system, in which reference numeral 1 is a mailer, and steam (2) generated in the zein 1 is supplied to the high-pressure turbine 2. Furthermore, it is supplied to the medium/low pressure turbine 4 via the reheater 3 of the Digi 1, and work is performed by the high pressure turbine 2 and the medium/low pressure turbine 4, and the generator 5 is connected to the high pressure turbine 2 and the medium/low pressure turbine 4. to drive. The steam that has worked in the medium/low pressure turbine 4 enters the condenser 6 where it is made into water.
Zane 1 again after passing through Nzo 10 and high pressure feed water heater 11
is refluxed to.

On the other hand, the end of the reheater 3 of the zein 1 from the high pressure turbine 2 passes through the heat storage steam extraction valve 14 and the check valve 15, and then passes through the heat storage steam 1
Steam supply line 18 connecting 6 and the peaking turbine 17
It is connected to the. Regenerator 1 of the steam supply line 18
The end of the connection side 6 is divided into two parts, one of which is provided with a gate valve 19 and a check valve that allows steam to flow only toward the heat storage device 16, and the other end is provided with a gate valve 19 and a check valve that allows steam to flow only toward the heat storage device 16. A check valve 21 and a gate valve 22 are provided to allow steam to flow. Further, a check valve 23 and a steam control valve are provided in the steam supply line 18 closer to the peak turbine 17 than the connection portion of the branch conduit 13 .

Therefore, when the thermal storage steam extraction valve 14 and the gate valve 19 are opened and the gate valve n and the steam control valve 2A are closed,
A portion of the steam discharged from the high pressure turbine 2 is transferred to the branch pipe 1
3 and a steam supply line 18 to a heat storage [6] where it is stored as hot water.

On the other hand, when the high-pressure turbine 2 and the medium/low-pressure turbine 4 are required to have a high load, the heat storage steam extraction valve 14 and the gate valve 19 are closed, and the gate valve n and the steam control valve 24 are opened. The stored hot water self-evaporates due to reduced pressure, and the steam enters the peaking turn 17 to perform work and is connected to the peaking turbine 17.
The single power generator 5 is driven to generate electric power. The steam that has worked in the peaking turbine 17 is condensed in the condenser 26, sent to the condensate storage tank by the pump 27 and stored there, and then while the steam is being supplied to the heat storage device 16,
The pump 29 returns the water to the condenser 6 or the condensate line downstream thereof.

In this way, this type of thermal power generation plant consists of a main power generation system A consisting of a zein 1, a high pressure turbine 2, a medium/low pressure turbine 4, etc., and a steam storage power generation system B consisting of a heat storage 16, a peak turbine 17, etc. When the daytime power demand is large, the main power generation system A generates power, and the steam storage power generation system B, which utilizes the thermal energy stored in the heat storage device 16, can also generate power.

However, in such power plants, the steam for storage is extracted from the low-temperature reheat steam line, so it is possible to directly input the steam for storage into the heat storage device 16, but the following problems arise. There is. That is, a low turbine load is required without reducing the zein load as much as possible, while a high load on the steam storage power generation system B may be required. Therefore, in order to meet this requirement, it is necessary to extract a large amount of storage steam from the main power generation system A. However, when a large amount of steam is extracted from low-temperature reheated steam, the amount of steam passing through the reheater 3 may decrease more than necessary, resulting in an overload. It is necessary to take measures to prevent overload on the reheater. In addition, if measures are not taken to prevent overload by extracting a large amount of low-temperature reheated steam from the reheater 3, a large amount of steam cannot be extracted from the low-temperature reheated steam, so the Day 2 load is adjusted according to the turbine load. It is necessary to lower the load to such an extent that the reheater 3 does not become overloaded, and therefore, a large amount of storage steam cannot be obtained, resulting in problems such as the load capacity of the steam storage power generation system B not being increased. On the other hand, the steam used for power generation in the steam storage power generation system B is substantially saturated steam because it is obtained from self-evaporation due to reduced pressure within the heat storage device. Therefore, the effective heat drop of the steam in the peak turbine is small, and in order to increase the load capacity of the steam storage power generation system B, it is necessary to obtain a large amount of storage steam.

In view of these points, the present invention makes it possible to use a high-calorie, large-capacity steam source as storage steam, making it possible to increase the capacity of a hydraulic turbine, and furthermore, it is possible to use a steam source with a high calorific value and a large capacity as storage steam. The purpose of the present invention is to provide a thermal power plant in which a steam storage power generation system can be easily installed in an existing thermal power plant without making any design changes. The heat storage is supplied to a steam supply line that bleeds air and supplies it to the heat storage, and also supplies high-temperature reheated steam to the heat storage or supplies steam from the heat storage to the peaking turbine. This system is characterized by being equipped with a heat storage heat exchanger that stores heat from the steam and uses the stored heat amount to heat the steam to the peak turbine.

An embodiment of the present invention will be described below with reference to FIG. Note that the same parts as in Figure 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 2, a branch conduit 13 for supplying storage steam to the heat storage device 16 is branched out from the high temperature reheat steam line, and the other end of the branch conduit 13 is connected to a heat storage steam bleed valve 14, It is connected to the middle of a steam supply line 18 that connects a heat storage device 16 and a peak turbine 17 via a check valve 15 .

By the way, in the steam supply line 18, on the side of the heat storage device 16 from the connection point of the branch conduit 13, there is a high temperature heat storage heat exchanger 31 using molten salt or metal that can utilize sensible heat or latent heat as a heat storage medium. is installed. The high-temperature storage heat exchanger 31 has a high-temperature tank 32 and a low-temperature tank 33. When high-temperature steam is passed through the high-temperature storage heat exchanger 31 in the direction of the heat storage device 16, the heat storage medium becomes the high-temperature steam. The steam transfers heat from the low-temperature tank 33 to the high-temperature tank 32, receives the superheated heat of the storage high-temperature steam, and is stored in the high-temperature tank 32, and conversely moves from the heat storage tank 16 toward the peak turbine 17. When steam flows, when the heat storage medium stored in the high temperature tank 32 moves from the high temperature tank 32 to the low temperature tank 33, heat is given to the steam passing through the high temperature storage heat exchanger 31 to turn it into superheated steam. .

Thus, when the load on the main power generation system A is low, the thermal storage steam extraction valve 14 and the gate valve 19 are opened, while the gate valve 22 and the steam control valve U are closed. Therefore, the high temperature reheated steam coming out of the reheater 3 is transferred to the branch conduit 13.
The heat storage steam is extracted by VC, the heat storage steam extraction valve 14, and the check valve 15.
After passing through the high temperature storage heat exchanger 31, the gate valve 1
9 and the reverse expansion side, it is introduced into the heat storage device 16 and stored as hot water. At this time, the high temperature storage heat exchanger 31
In the process, the extracted high-temperature reheated steam exchanges heat with the heat storage medium and gives heat to the heat storage medium, and the amount of superheated heat is removed from the steam itself, reducing the amount of heat released during conversion from steam to hot water. Easily stored as hot water in heat storage.

On the other hand, when the power demand increases and the load request to the plant becomes high, and the main power generation system A becomes unable to bear the load, the thermal storage steam extraction valve 14 and the gate valve 19 are closed, and the gate valve 14 and the steam control valve U are closed. is controlled in the opening direction.

Therefore, the hot water stored in the heat storage device 16 is depressurized by the opening operation of the steam control valve, self-evaporates into steam, and receives heat from the heat storage medium when passing through the high temperature heat storage heat exchanger 31. After it becomes superheated steam - single turbine 17
The electricity flows into the engine, performs work there, drives the peak generator 5, and generates electric power. And the peak turbine 1
The steam discharged from 7 is condensed in a condenser 26,
The condensate in the condensate storage tank 28 is stored in the water storage tank by the pump 27, and then when steam is supplied from the main power generation system A to the steam storage power generation system B, the condensate in the condensate storage tank 28 is stored in the condenser 6 or the main power generation system. The water is returned to the power generation system throttle condensate/water supply line.

As explained above, in the present invention, the steam to be stored in the heat storage device is extracted from the high-temperature reheating steam line, so a large amount of storage steam can be stored without much change in the steam passing through the reheater. Air can be extracted from the power generation system. Moreover, since the amount of steam passing through the reheater does not change due to the extraction of storage steam, there is no need to take measures to prevent excessive loading of the reheater, and the load on the zeiler is reduced only by the amount of storage steam extracted. It is possible to reduce the turbine load by reducing the amount of water, and furthermore, it is possible to obtain steam with a high calorific value and large capacity as storage steam. Furthermore, in the present invention, since a high-temperature storage heat exchanger is provided, it is possible to temporarily store the heat amount of the superheated amount of the storage steam, thereby minimizing the loss of the heat amount of the storage steam. A large amount of heat can be stored, and on the other hand, the heat storage allows the steam used in the peak turbine to be superheated, increasing the effective heat drop of the steam in the two-way turbine, and increasing the turbine height. It is possible to improve efficiency. In this way, the load capacity of the peak turbine can be increased and the stored heat can be used effectively. It is also possible to increase the load capacity of the entire thermal power plant without changing the load capacity. Moreover,
This has the effect of increasing the load capacity of an existing thermal power plant and making it possible to easily respond to fluctuations in power demand without making any particular changes to the design technology of the existing power plant.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a power generation plant having a conventional steam storage power generation system, and FIG. 2 is a system diagram of a power generation plant having a steam storage power generation system according to the present invention. 1... Digi, 2... High pressure turbine, 3... Reheater, 4... Medium/low pressure turbine, 13... Branch conduit,
14... Heat storage steam bleed valve, 19, 22... Gate valve, U... Steam control valve, 16... Heat storage device, 17...
Peak turbine, 30... High temperature reheat steam line, 3
1... High temperature storage heat exchanger, 32... High temperature tank, 33
...low temperature chamber. Applicant's agent Kiyoshi Inomata

Claims (1)

[Claims] A steam storage power generation system is provided, in which a part of the steam generated by the zein is stored in a heat storage device, and a peak turbine is driven by the steam stored in the heat storage device when a high load is required. In a thermal power plant, high-temperature reheated steam is extracted and supplied to the heat storage device, and steam is supplied to the heat storage device or steam from the heat storage device is supplied to the peak turn. A steam storage power generation system characterized in that a heat storage heat exchanger is disposed in the supply line to store heat from the steam supplied to the heat storage device and heat the steam to the peak turbine using the stored heat amount. Thermal power plant. (1) Oh!