JPH01190904A - Cooling water controller for bearing - Google Patents

Abstract

PURPOSE:To reduce the electric power necessary for the pump operation by supplying the cooling water from a pump having a small capacity into a cooler which requires the cooling water when power generation is suspended. CONSTITUTION:The cooling water whose pressure is increased by the pumps 1-3 arranged in parallel is supplied into heat exchangers 8-11. When power generation is suspended, all the pumps 1-3 are brought into stop, and a pump 21 having a small capacity is started. The cooling water whose pressure is increased by the pump 21 having the small capacity is supplied into the heat exchangers 8 and 10 which require the continuous feed of the cooling water. Therefore, the electric power necessary for the pump operation can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a bearing cooling water system for a prime mover power generation plant.
In particular, the present invention relates to a control device that is effective in reducing the power required for a cooling water supply pump when power generation is stopped and in appropriately distributing flow rates to each heat exchanger.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 52-109005, conventional equipment maintains the heat exchanger outlet temperature of the cooled fluid constant when the heat load on each heat exchanger changes during partial load operation of a single power plant. By separating the heat exchanger, which requires a temperature control device to adjust the amount of cooling water to maintain the temperature, and the cooling water supply main pipe of the heat exchanger, which does not require a temperature control device, changes in the flow rate of both systems can be prevented. This was to prevent mutual influence.

However, when the required amount of cooling water and flow rate distribution for each heat exchanger change with characteristics different from those during normal partial load operation of the plant, such as when power generation is stopped at night in a plant, the appropriate amount of cooling water for each heat exchanger cannot be determined. No consideration was given to the distribution of cooling water and measures to reduce the shaft power of the pump for supplying cooling water.

[Problem to be solved by the invention]

The above conventional technology is applicable to cases where the amount of cooling water required for each heat exchanger decreases due to characteristics different from normal plant partial load operation, such as when power generation is stopped at night, and the flow distribution changes. As a result, under this operating condition, the flow rate balance of the entire bearing cooling water system is disrupted, and there are areas where excessive cooling water flows locally, damaging the heat exchanger, or conversely causing damage to the heat exchanger. There was a risk that the cooling fluid could not be cooled to the required temperature.

In addition, such an unbalance in flow rate results in a request to supply water that exceeds the cooling water supply capacity of the pump, and although the required amount of cooling water for the cooler decreases, this does not lead to a reduction in the shaft power of the cooling water pump. This caused a problem.

The purpose of the present invention is to install a small-capacity pump that can secure the required amount of water for each heat exchanger under such operating conditions, and to properly distribute the flow rate to each heat exchanger using the discharge pressure within the capacity of this pump. By installing a cooling water supply bypass system that can reduce pump shaft power and supply an appropriate amount of cooling water to each heat exchanger, damage to the cooler due to excessive amount of cooling water and reduction in the amount of cooling water can be avoided. The purpose is to compensate for the lack of cooling capacity due to insufficient cooling capacity.

[Means to solve the problem]

The above purpose is to install a small capacity pump capable of supplying the total amount of cooling water required for each heat exchanger under such operating conditions, and to supply the required amount of cooling water to each heat exchanger at a discharge pressure within the supply capacity of this pump. In order to properly distribute the amount of cooling water,
A cooling water supply bypass system is installed in the cooling water supply piping to each heat exchanger, with an orifice etc. installed to adjust the amount of cooling water supplied, allowing the power plant to switch from normal power plant load operation to power generation shutdown. At the transition stage, this is achieved by starting this small capacity pump and supplying cooling water to each heat exchanger via this bypass system.

[Effect]

When the power generation plant stops generating power, the cooling water supply pump used during normal load operation will stop, the small capacity pump installed in this invention will automatically start, and the main valve of the cooling water supply bypass system will stop. will open automatically. This bypass system is equipped with an orifice, etc., so that the amount of cooling water under such operating conditions is distributed appropriately, and the discharge pressure of this small capacity pump is also adjusted to match the amount of cooling water and flow rate distribution. Because it is selected taking into consideration the pressure loss of the cooling water system.

It becomes possible to optimize the total amount of cooling water required and the flow rate distribution in this operating state.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a schematic configuration of a bearing cooling water system of a motor power generation plant.

During normal plant load operation, pumps 1, 2 . The cooling water pressurized in steps 3 and 3 is cooled with a lower temperature fluid in a cooler 4, and a temperature control valve 5 mixes the cold water that has passed through the cooler 4 with the hot water that has bypassed the cooler, and controls the temperature to a constant temperature. After that, the pressure of the cooling water supply main pipe is controlled to be constant by the pressure regulating valve 6, and from this cooling water supply main pipe 7, the heat exchangers 8, 9, 1 provided in each device are
0 and 11. On the other hand, heat exchanger 8,9゜10
The cooling water heated by exchanging heat with the fluid to be cooled in and 11 passes through return pipes 12, 13, 14, and 15.

It collects in the return main pipe 16 and is again supplied to the pump pushing side. In addition, for those that require constant control of the outlet temperature of the cooling heat exchanger for the fluid to be cooled, use the temperature control valve 1.
7 and 18 are installed in the cooling water piping, and the temperature of the fluid to be cooled is detected by temperature regulators 19 and 20, which is converted into a control signal and the amount of cooling water is adjusted by temperature regulating valves 17 and 18. There is.

Next, the flow of the cooling fluid when the plant power generation is stopped will be explained.

Note that heat exchangers 8 and 10 are required to continue supplying cooling water in the actual operating state.

In the case of normal operation, pumps 1 and 2 for normal cooling water supply
and 3 are all stopped, the small capacity pump 21 according to the present invention is started, the cooling water supply stop valves 22 and 23 are closed, and the main valve 24 of the bypass system according to the present invention is fully opened. In this case, the cooling water pressurized by the small capacity pump 21 is supplied to the heat exchangers 8 and 11 through orifices 26 and 27 installed in the bypass system 25 branching from the outlet of the temperature regulating valve 5. The return water from heat exchangers 8 and 11 is
through the same flow path as during normal plant load operation.
Circulate again to the small capacity pump. In addition, 28°29.30
and 31 are check valves, and by installing these check valves,
Backflow of cooling water can be prevented in transient situations when switching channels.

In this way, by sending cooling water from the small capacity pump to the heat exchanger via the bypass system when the prime mover power generation plant is under no load, it becomes possible to optimize the distribution of the amount of cooling water in this operating state. This prevents damage to the heat exchanger due to excessive flow due to the reduction of pressure loss in the cooling pipes in the heat exchanger 11, which does not perform temperature control of the cooled fluid, and prevents overcooling of the cooled fluid. At the same time, for the heat exchanger 8 that performs temperature control,
This means making it possible to secure the required amount of cooling water and preventing deterioration of the cooling performance of the fluid to be cooled due to the amount of cooling water being lower than the required value. Furthermore, by controlling the amount of cooling water in each heat exchanger to the required amount when the prime mover power generation plant is under no load, the total amount of cooling water can also be reduced, which in turn reduces the shaft power of the pump. Especially in the case of the present invention.

Since a dedicated small-capacity pump is installed to obtain high efficiency in the actual operating state, it is possible to operate with further reduced shaft power.

FIG. 2 shows another embodiment. In this embodiment, the cooling water stop valves 22 and 23 are changed from automatic valves to manual valves, and instead, a supply source valve 34 of the automatic valve is installed in the cooling water supply main pipe 7.
It was designed. The operation of the supply source valve is the same as the cooling water stop valves 22 and 23 shown in the embodiment, and the effects of the invention are also the same as in the embodiment. 32 in the figure is a temperature regulator;
33 is a pressure regulator.

According to this embodiment, since cooling water is supplied to each heat exchanger via a bypass system designed to achieve optimal flow distribution under operating conditions, it is possible to optimize cooling water volume distribution. This prevents damage to the heat exchanger and overcooling of the fluid to be cooled due to excessive flow inflow, and also prevents deterioration of cooling performance of the fluid to be cooled due to inability to secure the required amount of cooling water.

According to the present invention, operating costs of a prime mover power plant can be reduced, and reliability of each heat exchanger in a bearing cooling water system can be improved.

〔Effect of the invention〕

According to the present invention, only the required amount of bearing cooling water can be supplied using a small-capacity pump during no-load operation of a prime mover power generation plant, so that the electric power required for pump operation can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of one embodiment of the present invention, and FIG. 2 is a system diagram of another embodiment of the invention. 21... Small capacity pump, 22... Cooling water stop valve, 23
... Cooling water stop valve, 24 ... Bypass source valve, 25 ...
・Bypass system, 26... Orifice, 27... Orifice, 28... Check valve, 29... Check valve, 30
... Check valve, 31 ... Check valve, 32 ... Supply source valve. Figure 1

Claims (1)

[Claims] 1. In a cooling water system of a prime mover power generation plant having a system that supplies cooling water extracted by a pump to each heat exchanger in parallel through pipes, the cooling water is supplied when power generation is stopped. A small-capacity pump capable of supplying the required amount of cooling water to the cooler that needs to be continuously operated is installed, and the amount of cooling water can be distributed according to the amount of cooling water required for the heat exchanger in the actual operating state. A bearing cooling water control device characterized by having a bypass system with a flow rate adjustment function.