JPS60222511A - Thermal power generating equipment - Google Patents

Abstract

PURPOSE:To enable a pump to be prevented from a trouble before its occurrence, by providing an automatic regulating valve parallelly to an operating valve in a turbine bypass passage and regulating the pressure of a liquefied thermal medium in a suction side of the pump so as to be higher than the saturated pressure through a pressure regulating meter. CONSTITUTION:An equipment, in its operation from a vaporizing mode to a thermal power generating mode, closes a valve 20 and starts a pump 7 at a point of time the liquid level of a liquefied thermal medium in a condenser 2 increases. The equipment, detecting this liquefied thermal medium in a suction side of the pump for the temperature by a temperature detector 29 while for the pressure by a pressure regulating meter 28, obtains the saturated temperature in an arithmetic device 30 and controls an automatic regulating valve 31 to be opened and closed by the pressure regulating meter 28 applying the higher pressure as the preset value. Accordingly, a trouble of the pump can be prevented before the occurrence by holding the pressure in the suction side of the pump 7 to the saturated pressure or more and eliminating the generation of cavitation of the pump. Further starting efficiency is improved by reducing a starting time to a necessary minimum limit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to cold power generation equipment that extracts electrical energy by utilizing the cold heat possessed by low-temperature liquefied gas such as liquefied natural gas.

[Background of the invention]

There are two operating modes for cold power generation equipment: a vaporization mode that only vaporizes low-temperature liquefied gas, and a cold power generation mode that generates electricity.The operating order is that the system first enters the vaporization mode and then shifts to the cold power generation mode. is common.

An example of conventional cold power generation equipment will be explained with reference to FIG.

Fig. 1 is a system diagram of a conventional cold power generation facility, in which the vaporized heat medium is supplied to a condenser 2t through a conduit 1, and the vaporized heat medium exchanges heat with the low-temperature liquefied waste supplied through a conduit 3. It is cooled and liquefied. Further, the low-temperature liquefied scum is heated by the heating medium e, vaporized, and sent through a conduit 4 to a local demand destination, such as a thermal power plant boiler (not shown). On the other hand, the liquefied heat medium liquefied in the condenser is transferred to conduits 5, 21. valve 20
．． Conduit 22°8, check valve 9. It is supplied via a conduit 10 to an evaporator installed at a lower position than the condenser 2, where it is supplied via a conduit 12. Heated with a heating source such as seawater.

vaporized. Thereafter, this vaporized heat transfer medium is transferred to the conduit ]3.2
4. Valve 23. refluxed to the condenser 2 via the conduit 25,1;
Here it is cooled and liquefied again. In vaporization mode operation, the operation continues while repeating such a cycle, and the operating pressure of the heating medium varies depending on the situation, the type of heating medium, and the temperature of the heating source, but in general, Several Kp/a/G
In addition, the condenser 2 and the lX generator 1 are operated under almost equal pressure conditions.

Next, the first method of transitioning to cold power generation mode will be explained.

In the cold power generation mode, in order to drive the expansion turbine (hereinafter referred to as turbine) 17, the outlet pressure of the turbine is naturally lower than the inlet pressure of the turbine.
The pressure in the condenser 2 is low, almost atmospheric pressure, whereas the pressure in the condenser 2 is a few Ky/-G, so the heat medium in the condenser 2 is transferred to the evaporator
1, it is necessary to operate the pump 7 that increases the pressure of the heat medium.

Generally, the operating procedure is to first close the valve 20, and as a result, the level of the heat transfer liquid in the condenser 2 rises, and the level gauge 2 indicates that the level has risen to a predetermined level. When confirmed, start pump 7. Next, the internal pressure of the condenser 2 is gradually lowered by gradually closing the valve 23, and when it is confirmed with the pressure gauge 271 that the pressure has decreased to a predetermined level, the valve 23 is closed gradually.
When the turbine 17 is opened and the turbine 17 is started, the single valve 23 is closed. As a result, the high pressure vaporized heat transfer medium from the evaporator 1] is transferred to the conduits 13, 14. Valent] 5. The turbine 17 is supplied through the conduit [6] and the turbine [7] starts rotating. By rotating the turbine 17, this vaporized heat medium converts the energy it possesses into mechanical energy, and further generates electricity 91.
One electric energy is converted and taken out by B, and it is used.
Ru. As a result of 17 tons of trowel work performed by the turbine, the vaporized heat medium whose temperature and pressure have decreased by 17 tons is transferred to the conduit]9. ] to condenser 1
The cold power generation operation continues while repeating this cycle.

Incidentally, since the pump 7 is a pump for liquefied gas, it must be operated in a predetermined NPSH state, that is, in a supercooled state.

That is, if the pump 17 is not operated in a supercooled state, a large number of air bubbles will be generated in the pump 17, causing cavitation and making pumping operation impossible.

Furthermore, since the processing fluid itself is used to lubricate the bearings of this type of pump, in extreme cases this can lead to serious accidents such as bearing burnout.

In such cold power generation equipment, in order to avoid problems with the pump, the valve 23, which is installed in the middle of the conduit that bypasses the turbine, is operated slowly, but the pressure drop rate still exceeds the allowable range. There remains a possibility that the pump 7 will cavitate and trip, resulting in startup failure.

[Purpose of the invention]

An object of the present invention is to provide a cold-thermal power generation facility that does not cause problems with pumps.

[Summary of the invention]

Great invention, in the middle of the bypass passage that bypasses the turbine? An automatic control valve is installed in parallel with this operating valve, and is designed to maintain the pressure of the liquefied heat medium at the inlet side of the pump for pressure increase by one point higher than its saturation pressure. It is characterized by the provision of a pressure regulator that automatically adjusts the pressure.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on specific examples.

FIG. 2 is a system diagram of a cold power generation facility in an embodiment of the present invention. In addition, with reference to Figure 2, the same as Figure 1.
Equipment etc. are given the same symbols. In Fig. 2, 2
Reference numeral 8 denotes a pressure regulator, which detects the pressure of the liquefied heat medium at the inlet side of the pump 7, and outputs an adjustment signal for adjusting this pressure to a set pressure higher than the saturation pressure.

A temperature detector 29 detects the temperature of the liquefied heat medium on the inlet side of the pump 70. The output of this temperature detector 29 is input to a computing unit 30. Based on the input temperature, the calculator 30 determines the saturation pressure of the liquefied heat medium at the temperature t, and outputs a pressure setting value higher than this to the pressure regulator 28#. 3J is an automatic control valve, which is automatically adjusted by the control signal t output from the pressure regulator 28. This control valve 31 is provided in the middle of a passage that bypasses the valve 15 and the expansion turbine 17, and the valves 23 and 23 are installed in parallel.
I'm here. 32 and 33 are conduits.

In this configuration, how does the transition from vaporization mode operation to cold power generation mode operation occur? Let's do this. first,
Close valve 20. As a result, the liquid level of the liquefied heat medium in the condenser 2 rises, and when the liquid level rises to a predetermined level, the pump 7 is started. From this start-up, the liquefied heat medium is sucked into the pump 7, and the temperature of the liquefied heat medium on the suction side (inlet side) is detected by the temperature detector 29. Similarly, the pressure of the liquefied heat medium is also detected by the pressure regulator 28. The computing unit 30 inputs the output of the temperature detector 29 and calculates the saturation pressure of the liquefied heat medium at that temperature.

A pressure higher than that is outputted as the set pressure of the pressure regulator 28. The pressure regulator 28 compares the set pressure with the detected actual pressure and determines if the actual pressure is higher than the set pressure.
1), the automatic control valve 3] is operated in the closing direction, and conversely, when the temperature is low, the automatic control valve 3] is operated in the open direction. For example, valve 2
When the pressure on the suction side of the pump 7 does not become lower than the set value of the pressure regulator 28 as a result of suddenly closing the automatic control valve 3,
1 opens automatically, so the pressure regulator 28 is on the suction side of the pump 7.
The set value of , that is, the supercooled state is maintained. Then, when the temperature of the heat medium decreases due to the pressure drop, the set value of the pressure regulator 28 is automatically lowered, and as this operation is repeated, the pressure continues to drop. Then, when it is confirmed by the pressure gauge 27 that the internal pressure of the condenser 2 has decreased to a predetermined pressure, for example, 0.5 KP/ciG, the valve 15 is opened and the turbine 17 is started.

As a result, the vaporized heat transfer medium from the evaporator J1 is transferred to the conduit】3.1
4. Square 15. Conduit] 6 is supplied to the turbine 17,
Turbine 17 starts rotating.

In the cold thermal power generation equipment as in this embodiment, the state of the suction part of the pump can be automatically maintained in a supercooled state under any circumstances, so the occurrence of cavitation in the pump can be prevented.
Not only is it possible to sufficiently prevent startup failures due to pump stoppage and burnout accidents of the pump bearings due to this rL, but also the startup time can be shortened to the necessary minimum, resulting in high startup efficiency and economy.

〔Effect of the invention〕

As explained above, according to the present invention, the pressure on the inlet side of the pump can be set to be equal to or higher than its saturation pressure. Since this can be maintained, problems with the pump will not occur.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a conventional cold power generation facility, and FIG. 2 is a system diagram of a cold power generation facility showing an embodiment of the present invention. ], 3 to 6.8, 10.12 to 14.16°19.
2], 22, 24, 25, 32. 33... conduit, 2... 11 equipment, 7... pump, 9...
...Check valve, 1] ...Evaporator, 15, 2
0, 23... Valve, 17... Turbine, J8... Generator, 26... Liquid level needle,
27...Pressure gauge, 28...Pressure regulator, 29...Temperature detector, 30...Calculator, 31...Automatic Control valve agent Patent attorney Masaru Ogawa Masaru 1 figure

Claims (1)

[Claims] 1. A condenser that liquefies the vaporized heat medium using the cold heat of the low-temperature liquefied gas, a pump that increases the pressure of the liquefied heat medium, and an evaporator.
It has a thermal cycle in which the valve No.], an expansion turpin driven by the supply of the vaporized heat medium vaporized by the evaporator, and the condenser are connected in series, and the pump No. 1'ff is connected in series. A second valve is provided in the middle of the bypass passage, a third valve is provided in the middle of the passage that bypasses the first valve and the expansion turbine, and a generator driven by the expansion turbine. In the cold power generation equipment, a fourth valve is provided in parallel with the third valve, and the pressure of the liquefied heat medium at the inlet side of the pump is maintained at a higher pressure than the saturation pressure. A cold-thermal power generation facility characterized by being provided with a pressure regulator that automatically adjusts the fourth valve.