JPH0968003A - Cooling water unit for turbine auxiliary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent differential pressure at a throttle valve from becoming excessively large due to the pressure increase of cooling water in a system generated in association with the decrease of cooling water flow in the system. SOLUTION: Cooling water from a cooling water temperature regulating part 2 for regulating the temperature of cooling water to be fed to a plurality of turbine auxiliary machines is led to a turbine auxiliary machine 1a continuously controlling cooling water flow and to a turbine auxiliary machine 1b not continuously controlling cooling water flow, through a cooling water supply main pipe 7, and the cooling water after cooling the turbine auxiliary machines is returned to the cooling water temperature regulating part 2 through a cooling water return main pipe 8. When the supply main pipe pressure of the cooling water supply main pipe 7 exceeds the prescribed value, a by-pass valve 14 of a by-pass pipeline 12 branching off from the cooling water supply main pipe 7 and by-passing the turbine auxiliary machines so as to be connected to the cooling water return main pipe 8 is opened, and when the supply main pipe pressure becomes the prescribed value or less, the by-pass valve 14 is closed to return to normal operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine auxiliary equipment cooling water facility for cooling heat generated in a turbine auxiliary equipment during operation of a power plant.

[0002]

2. Description of the Related Art Generally, a power plant is equipped with a turbine accessory cooling facility for cooling a turbine accessory. A turbine auxiliary machine to be cooled is provided with a heat exchanger for turbine auxiliary equipment, and cooling water is supplied to the heat exchanger to cool the turbine auxiliary machine. For example, the turbine auxiliary equipment cooling facility supplies cooling water to a turbine oil cooler, an electric motor cooler, a heat exchanger for an auxiliary device of the turbine such as a heat exchanger for air conditioning, and cools it.

FIG. 4 shows a conventional turbine auxiliary equipment cooling water facility. The temperature of the cooling water supplied to the turbine accessories 1a and 1b is adjusted by the cooling water temperature adjusting section 2. That is, the cooling water boosted by the pump 3 has a piping system through the cooling water temperature control valve 4a, the heat exchanger 5 and the cooling water temperature control valve 4b.
So that the cooling water temperature of the cooling water supply mother pipe 7 detected by the thermometer 6 reaches a predetermined value, the opening degree of the cooling water temperature control valve 4a and the cooling water. The opening degree of the temperature control valve 4b is adjusted to control the cooling water temperature of the cooling water supply mother pipe 7. That is, the cooling water temperature is controlled by adjusting the flow rate of the low temperature cooling water that has passed through the heat exchanger 5 and the flow rate of the high temperature cooling water that does not pass through the heat exchanger 5.

The temperature-controlled cooling water is supplied to the turbine auxiliaries 1a and 1b via the cooling water supply mother pipe 7 and exchanges heat with the fluid to be cooled in the turbine auxiliaries 1a and 1b, and then returns to the cooling water. It returns to the suction side of the pump 3 via the mother pipe 8.

The method of setting the flow rate of the cooling water flowing through the turbine accessories 1a, 1b is roughly classified into two. One is a setting method of continuously controlling the water flow rate to the heat exchanger in the turbine auxiliary machine 1a, and the other is a setting method of not continuously controlling the water flow rate to the heat exchanger in the turbine auxiliary machine 1b. Is the way.

A method for continuously controlling the flow rate of water flowing to the heat exchanger in the turbine auxiliary machine 1a is to install a cooling water control valve 9 at the outlet or inlet of the heat exchanger of the turbine auxiliary machine 1a, and The control valve 9 continuously controls the flow rate of the cooling water supplied to the heat exchanger of the turbine auxiliary machine 1a. In FIG. 4, the cooling water control valve 9 is shown installed at the outlet of the heat exchanger of the turbine accessory 1a. The cooling water control valve 9 detects the temperature or pressure of the fluid to be cooled in the heat exchanger of the turbine auxiliary machine 1a by the detector 10, and controls the cooling water flow rate so that the temperature or pressure of the fluid to be cooled reaches a predetermined value. The increase / decrease is controlled.

On the other hand, the setting method which does not continuously control the water flow rate to the heat exchanger in the turbine auxiliary machine 1b is the turbine auxiliary machine 1
The cooling water control valve 9 is not installed at both the inlet and the outlet of the heat exchanger of b. Instead, throttle valves 11a and 11b are provided, and the water flow rate is preset by throttling the throttle valves 11a and 11b. The throttle valves 11a and 11b are
The turbine auxiliary machine 1b is provided at either or both of the outlet and the inlet of the heat exchanger. In FIG. 4, those provided at both the outlet and the inlet are shown. As described above, the water flow rate is set in advance by throttling the throttle valves 11a and 11b, but since it is not continuously controlled, the throttle valve 11a,
The valve opening of 11b often remains constant.

[0008]

However, the water flow rate to the heat exchanger of the turbine auxiliary machine 1b, which does not continuously control the water flow rate, is determined by the pressure of the cooling water supply mother pipe 7 and the cooling water return mother pipe 8. If the difference becomes large, the throttle valve 11 is fixed to a predetermined valve opening, and therefore the flow rate increases to a flow rate corresponding to this differential pressure. When the cooling water flow rate increases, the differential pressure of the throttle valve 11 also increases, so that vibration or cavitation due to excessive differential pressure may occur.

The fluctuation of the pressure difference between the cooling water supply mother pipe 7 and the cooling water return mother pipe 8 is caused by the fluctuation of the water flow rate of the heat exchanger of the turbine auxiliary machine 1a which continuously controls the water flow rate. Occurs. That is, in some heat exchangers of the turbine auxiliary machine 1a that continuously control the water flow rate, the water flow rate of the heat exchanger occupies about 20 to 40% of the total flow rate in the turbine auxiliary machine cooling water system. .

FIG. 5 shows the characteristics of the mother pipe pressure P and the cooling water flow rate Q in the system. In FIG. 5, PI is a characteristic curve of the cooling water supply mother pipe pressure, and PO is a characteristic curve of the cooling water return mother pipe pressure. Here, the flow rate of the entire system when the water flow rate to the turbine auxiliaries 1a and 1b is the maximum is Q1, and the turbine auxiliaries 1
Let Q2 be the flow rate of the entire system when the flow rate of water to a and 1b is minimum. Let PI1 be the cooling water supply mother pipe pressure at the maximum water flow rate Q1, PI2 be the cooling water supply mother pipe pressure at the minimum water flow rate Q2, and the cooling water return mother pipe at the maximum water flow rate Q1. When the pressure is PO1 and the cooling water return mother pipe pressure at the minimum water flow rate Q2 is PO2, the following relationship is established.

In-system cooling water flow rate Q1> Q2 Cooling water supply mother pipe pressure PI1 <PI2 Cooling water return mother pipe pressure PO1> PO2 This is because the cooling water supply mother pipe pressure PI is the pump Q-H characteristic and pressure loss, and This is because the cooling water return mother pipe pressure PO is determined by the pressure loss. That is, when the in-system cooling water flow rate decreases, the pressure difference between the cooling water supply mother pipe pressure PI and the cooling water return mother pipe pressure PO tends to increase, and the turbine accessory 1b that does not continuously control the water flow amount. If the pressure difference between the cooling water supply mother pipe 7 and the cooling water return mother pipe 8 increases, the amount of water passing through the heat exchanger will increase to a flow rate corresponding to this pressure difference.

FIG. 6 shows the characteristics of the differential pressures of the heat exchanger main body, the piping, and the throttle valve 11 in the heat exchanger of the turbine auxiliary machine 1b, which does not continuously control the water flow rate. In FIG. 6, ΔP1 is the throttle valve differential pressure, ΔP2 is the pipe differential pressure, and ΔP3 is the heat exchanger differential pressure. As can be seen from FIG. 6, when the flow rate of the cooling water increases from Q1A to Q2A, the differential pressure ΔP1 of the throttle valve 11 also increases. As a result, there are problems such as vibration or cavitation due to excessive pressure difference.

An object of the present invention is to provide a turbine auxiliary equipment cooling water facility capable of preventing an excessive increase in the differential pressure at the throttle valve due to an increase in the system cooling water pressure due to a decrease in the system cooling water flow rate. Is to provide.

[0014]

According to a first aspect of the present invention, there is provided a cooling water temperature adjusting section for adjusting the temperatures of cooling water supplied to a plurality of turbine accessories, and cooling water from the cooling water temperature adjusting section. Cooling water supply mother pipe for guiding to each turbine auxiliary machine,
A cooling water control valve that continuously controls the flow rate of cooling water that is guided from the cooling water supply mother pipe and supplies it to a specific turbine auxiliary machine among a plurality of turbine auxiliary machines, and cooling that is guided from the cooling water supply mother cylinder. A throttle valve that supplies the flow rate of water to a turbine accessory other than a specific turbine accessory with a preset valve opening, and cooling water that has finished cooling multiple turbine accessories to the cooling water temperature control unit. Cooling water return mother pipe for returning, bypass pipe branched from the cooling water supply mother pipe and connected to the cooling water return mother pipe bypassing the turbine auxiliary equipment, and supply of the cooling water supply mother pipe provided in the bypass pipe And a bypass valve that opens when the mother pipe pressure exceeds a predetermined value and closes when the mother pipe pressure falls below the predetermined value. As a result, when the cooling water flow rate in the system increases and the cooling water pressure in the system increases, the bypass valve provided in the bypass pipe is opened to flow the cooling water in the bypass pipe. Therefore, the flow rate of cooling water in the system increases, and as a result, the pressure of cooling water in the system decreases. When the cooling water pressure in the system reaches a predetermined value, the bypass valve is closed and normal operation is resumed.

According to a second aspect of the present invention, in the first aspect of the invention, the bypass valve is used as a control valve, and the flow rate of the cooling water flowing through the bypass pipe is controlled so that the supply pipe pressure of the cooling water supply pipe becomes a predetermined value. It was adjusted. Thereby, the cooling water flow rate in the system can be continuously controlled.

According to a third aspect of the present invention, in the first aspect of the present invention, the bypass valve is opened when the flow rate of the cooling water in the cooling water supply mother pipe exceeds a predetermined value, and closed when the flow rate is below the predetermined value. It is something that is done.

[0017]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a first embodiment of the present invention. In the first embodiment, the bypass pipe 12 branched from the cooling water supply mother pipe 7 and bypassing the turbine auxiliaries 1a and 1b and connected to the cooling water return mother pipe 8 and the pressure provided in the bypass pipe 12 are provided. The bypass valve 14 is opened when the supply mother pipe pressure PI of the cooling water supply mother pipe 7 detected by the total 13 exceeds a predetermined value and closes when the supply mother pipe pressure PI falls below the predetermined value.

In FIG. 1, the temperature of the cooling water supplied to the turbine accessories 1a and 1b is adjusted by the cooling water temperature adjusting section 2. That is, the cooling water boosted by the pump 3 is branched and supplied to the piping system via the cooling water temperature control valve 4a and the piping system via the heat exchanger 5 and the cooling water temperature control valve 4b. Then, the valve opening of the cooling water temperature control valve 4a and the valve opening of the cooling water temperature control valve 4b are adjusted so that the cooling water temperature of the cooling water supply mother pipe 7 detected by the thermometer 6 becomes a predetermined value. Then, the cooling water temperature of the cooling water supply mother pipe 7 is controlled.
In this way, by adjusting the flow rate of the low-temperature cooling water that has passed through the heat exchanger 5 and the flow rate of the high-temperature cooling water that does not pass through the heat exchanger 5, the turbine auxiliary machines 1a and 1b are supplied. The temperature of the cooling water is controlled.

The temperature-controlled cooling water is supplied to the turbine auxiliaries 1a and 1b via the cooling water supply mother pipe 7, and heat-exchanged with the fluid to be cooled by the heat exchangers in the turbine auxiliaries 1a and 1b. After that, it returns to the suction side of the pump 3 via the cooling water return mother pipe 8.

A bypass pipe 12 is provided which branches from the cooling water supply mother pipe 7 and bypasses the turbine auxiliary machines 1a and 1b and is connected to the cooling water return mother pipe 8. A bypass valve 14 is provided in the bypass pipe 12,
The bypass valve 14 is opened when the supply mother pipe pressure PI of the cooling water supply mother pipe 7 detected by the pressure gauge 13 exceeds a predetermined value and closed when the supply mother pipe pressure PI is below the predetermined value. Thus, when the in-system cooling water pressure P increases as the in-system cooling water flow rate Q decreases, the bypass valve 12 provided in the bypass pipe 12 is opened to open the bypass pipe 12
Pour cooling water into. Therefore, the in-system cooling water flow rate Q increases, and as a result, the in-system cooling water pressure P decreases. When the in-system cooling water pressure P reaches a predetermined value, the bypass valve 14 is closed and normal operation is resumed.

According to the first embodiment, when the cooling water supply mother pipe pressure PI of the cooling water supply mother pipe 7 exceeds a predetermined value, the bypass valve 1 installed in the bypass pipe 12 is provided.
Since the flow rate Q of the cooling water flowing through the system is increased by opening No. 4, the cooling water supply mother pipe pressure PI is reduced. Therefore, it is possible to prevent an increase in the differential pressure of the throttle valve 11, and it is possible to suppress the occurrence of vibration or cavitation due to excessive differential pressure.

Next, FIG. 2 shows a second embodiment of the present invention. The second embodiment differs from the first embodiment shown in FIG. 1 in that the bypass valve 14 is a control valve 15.
The flow rate of the cooling water flowing through the bypass pipe 12 is adjusted so that the supply pipe pressure PI of the cooling water supply pipe 7 becomes a predetermined value. As a result, the cooling water flow rate Q in the system
Control continuously. Other configurations are the same as those of the first embodiment shown in FIG. 1, and therefore, the same components are denoted by the same reference symbols and description thereof will be omitted.

According to this second embodiment, the control valve 1
5 continuously controls the supply mother pipe pressure PI detected by the pressure gauge 13 to a predetermined value, the throttle valve 11
The turbine auxiliary machine 1b can be cooled under the optimum differential pressure condition.

Next, FIG. 3 shows a third embodiment of the present invention. In the third embodiment, the bypass valve 14 is
When the cooling water flow rate of the cooling water supply mother pipe 7 detected by the flow meter 16 exceeds a predetermined value, it is opened, and when it is below a predetermined value, it is closed. Other configurations are shown in FIG.
Since it is the same as that of the first embodiment shown in FIG. 1, the same elements are denoted by the same reference numerals and the description thereof will be omitted.

According to the third embodiment, when the in-system water flow rate Q becomes equal to or less than the preset flow rate, the bypass valve 14 is opened, so that the in-system water flow rate Q increases and the cooling water flows. It is possible to suppress an increase in the supply mother pipe pressure PI, and it is possible to prevent vibration or cavitation from occurring in the throttle valve 11 due to an excessive pressure difference.

Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the control valve 15 in the second embodiment shown in FIG. 2 is replaced with the cooling water flow rate of the cooling water supply mother pipe 7 detected by the flow meter 16 in the third embodiment. The adjustment is based on. That is, the flow rate of the cooling water flowing through the bypass pipe 12 is adjusted so that the flow rate of the cooling water in the cooling water supply mother pipe 7 becomes a predetermined value.

According to the fourth embodiment, the control valve 1
5 continuously controls the flow rate Q of the supply mother pipe flow detected by the flow meter 16 so that the flow rate Q becomes a predetermined value.
The turbine auxiliary machine 1b can be cooled under the optimum condition with the differential pressure of 1 always.

[0028]

As described above, according to the present invention, it is possible to prevent the differential pressure in the throttle valve from becoming excessively large due to the increase in the system pressure due to the decrease in the system flow rate. Therefore, it is possible to always maintain the differential pressure of the throttle valve of the turbine auxiliary machine that does not continuously control the water flow rate under optimum conditions, and cool the turbine auxiliary machine that does not continuously control the water flow rate under optimal conditions. it can.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a system configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a system configuration diagram showing a third embodiment of the present invention.

FIG. 4 is a system configuration diagram of a conventional example.

FIG. 5 is a characteristic diagram showing characteristics of an in-system cooling water flow rate and an in-system cooling water pressure in a conventional example.

FIG. 6 is a characteristic diagram showing characteristics of a water flow rate of a heat exchanger in a turbine auxiliary machine and a differential pressure of each part in a conventional example.

[Explanation of symbols]

 1 Turbine auxiliary machine 2 Cooling water temperature control part 3 Pump 4 Cooling water temperature control valve 5 Heat exchanger 6 Thermometer 7 Cooling water supply mother pipe 8 Cooling water return mother pipe 9 Cooling water control valve 10 Temperature or pressure detector 1 1 Throttle valve 12 Bypass piping 13 Pressure gauge 14 Bypass valve 15 Control valve

Claims (3)

[Claims] 1. A cooling water temperature adjusting section for adjusting the temperature of cooling water supplied to a plurality of turbine accessories, and a cooling water temperature adjusting section for guiding the cooling water from the cooling water temperature adjusting section to each of the turbine accessories. A cooling water supply mother pipe, and a cooling water control valve for continuously controlling the flow rate of the cooling water introduced from the cooling water supply mother pipe and supplying it to a specific turbine auxiliary machine of the plurality of turbine auxiliary machines, A throttle valve that supplies a flow rate of cooling water introduced from the cooling water supply mother pipe to a turbine auxiliary machine other than the specific turbine auxiliary machine at a preset valve opening degree, and cools the plurality of turbine auxiliary machines. A cooling water return mother pipe for returning the cooling water that has been finished to the cooling water temperature control unit, and a turbine auxiliary machine cooling water facility for cooling the heat generated in the turbine auxiliary machine with the operation of a power plant, Branch from the cooling water supply mother pipe A bypass pipe connected to the cooling water return mother pipe by-passing the auxiliary machine and a supply mother pipe pressure of the cooling water supply mother pipe provided in the bypass pipe exceeds a predetermined value, and is opened to a predetermined value. A turbine auxiliary equipment cooling water facility comprising a bypass valve that closes when the following occurs. 2. The bypass valve is a control valve, and a flow rate of the cooling water flowing through the bypass pipe is adjusted so that a supply pipe pressure of the cooling water supply pipe becomes a predetermined value. The turbine auxiliary equipment cooling water facility according to claim 1. 3. The bypass valve is opened when the flow rate of the cooling water in the cooling water supply mother pipe exceeds a predetermined value and closed when the flow rate of the cooling water is below the predetermined value. Item 2. A turbine auxiliary equipment cooling water facility according to Item 1.