JPS605763B2 - Starting system for liquefied natural gas cold power generation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a starting system for a liquefied natural gas (LNG) cold thermal power generation device.

(Prior Art) An overview of an LNG cryogenic power generation device using an intermediate heat medium (for example, propane) is as follows with reference to FIG. 1, which shows an example of the present invention.

LNGI is supplied to an intermediate heat medium condenser 2 where it is flooded and vaporized, and further flooded with seawater 4 by a heater 3 .

On the other hand, the intermediate heat medium condensed by the cold heat of LNG is
Kamakura is supplied from the condenser 2 to the evaporator 6 by the pump 6,
Here, it is flooded with seawater 4 and evaporated. The vaporized intermediate heat medium is then supplied to the turbine 7 of the generator, and after its pressure is used to drive the turbine, it is returned to the condenser 2 as turbine exhaust and is condensed again. During power generation operation, the operation of the pump 5 normally creates a pressure difference of approximately 5k9/Chu G between the evaporator on the high pressure side and the condenser on the low pressure side, and this is used to drive the turbine 7. .
When starting up such a power generation device, "to explain with reference to FIG.
After setting the turbine cooling water, generator operating power, etc. to normal, open the turbine inlet valve 8 at time (t,) and then close the turbine bypass valve 9, IQ and pump bypass valve volume 1 to close the condenser 2 and evaporator. Each device 6 is put into an independent system state,
Stops the natural circulation of the intermediate heat transfer medium.

In this state, seawater 4 is supplied to raise the intermediate heat medium pressure a of the evaporator 6 to a pressure commensurate with the seawater temperature, and the LNG
By supplying I at a set flow rate gradient b, the intermediate heat medium pressure c in the condenser 2 is gradually lowered. In this manner, a pressure difference begins to occur at the inlet and outlet of the turbine 7. Condenser 2
The intermediate heat medium cooled by circulating through the gas venting pipe 12 cools the pump 5 and its piping system. The pressure c of the condenser 2 is set to A pressure, usually OKG/G, so as to produce the above-mentioned pressure difference during power generation operation, and when this value is reached, it is detected by the controller P, and the signal is The /zzle 14 of the turbine is opened.

The nozzle 14 is connected to the condensing means 2 through a controller PIC so that the opening degree of the nozzle i4 is adjusted in accordance with fluctuations in the value of the pressure c. By opening the turbine nozzle 14, the high-pressure intermediate heat medium of the evaporator 6 flows into the turbine 7, which starts its rotation. When the specified rotational speed is reached, the generator circuit breaker is turned on, the motor is operated to raise the specified rotational speed, and power generation operation begins. On the other hand, in parallel with this, the intermediate heat medium liquid level in the evaporator 6 decreases, so the gas venting pipe 12 is closed. At this time, in order to prevent the pump 5 from starting at full load and running dry, the evaporator liquid level control valve 13 on the pump discharge side is fully closed. The pump is started and continues to operate while ensuring the minimum flow rate necessary for the pump.Meanwhile, when the liquid level in the evaporator 6 falls below the set value, its control valve 13 is opened and the pump is controlled to the set value. When the pressure c of the condenser reaches the set value A, the nozzle 14 of the turbine 7 is opened, and the intermediate heat medium at the inlet and outlet of the turbine is activated. As mentioned above, the large pressure difference causes an overshoot, making it difficult to control the pressure c at point A, as shown by the dotted line in Figure 2, and at the same time, the open state d of the turbine nozzle 14 also fluctuates. , it is difficult to expect smooth startup of the power generation device.

(Object of the Invention) The present invention has been devised to solve such problems at the time of starting up the power generation device, and can prevent the above-mentioned overshoot from occurring and smoothly start up the power generation device. The goal is to provide a system.

(Structure and Effect of the Invention) That is, the feature of the present invention is that the turbine nozzle 14 is forcibly opened when the pressure c reaches a value (A+Q) that is a predetermined value higher than the set value of the pressure c, and then the pressure c is set to the set value A. The purpose is to open the turbine nozzle 14 in conjunction with the change in the value of the pressure c when the pressure c reaches the value c.

Specifically, the above pressure c is A+ minus, for example, A0lk9/
When reaching Sakaki G), turn the turbine nozzle 14 to e in Figure 2.
When it is forcibly opened as shown in , the intermediate heat medium flows through the turbine 7 due to the pressure difference between the turbine input and output.
The pressure c temporarily increases as shown by the solid line, but then gradually decreases and reaches the set value A.

At this point, even if the opening of the turbine nozzle 14 is linked to the fluctuation in the value of the pressure c as described above, the pressure c is maintained at the set value A, and therefore the open state of the turbine nozzle 14 is also constant, thereby causing the power generating device will be able to start up smoothly.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing an example of the device of the present invention, and FIG. 2 is a graph for explaining its startup system.
1 is the LNG, 2 is the intermediate heat medium condenser, 6 is its evaporator, 5 is the pump, 7 is the turbine. 14 is the nozzle. Fig. 1 Fig. 2

Claims (1)

[Claims] 1 Liquefied natural gas cold heat that is used to vaporize the liquefied natural gas and evaporate the condensed intermediate heat medium, supply it to the generator turbine and use it to drive it, and then circulate and use it again to vaporize the liquefied natural gas. In the power generation device, the pressure in the intermediate heat medium evaporation means is maintained at a set value, and the pressure in the intermediate heat medium condensation means is lowered by supplying liquefied natural gas at a predetermined gradient, so that the pressure is lower than the set value during power generation operation. When the pressure reaches a predetermined value, the nozzle of the turbine is opened and the intermediate heat medium is allowed to flow from the evaporating means side to the condensing means side, while the pressure is lowered to the above set value, and when the set value is reached, the pressure is lowered. A starting system for a power generator, characterized in that the condensing means and the nozzle are connected so as to adjust the opening/closing state of the nozzle of the turbine according to a change in the value of .