JPS58195756A - Method of operating cryogenic liquefying refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a cryogenic liquefaction refrigeration system, particularly in conjunction with a variable refrigeration load.

To explain a helium refrigeration system as an example of a conventional ultra-low @ liquefaction refrigeration system with reference to FIG. 1, helium gas pressurized by a compressor 1 is guided through a high-pressure pipe 4 into a recall box, and is then passed through a JIl heat exchanger. After being cooled by the liquid nitrogen led from the liquid nitrogen pipe 4 and the low-temperature return gas led from the low-pressure pipe and the decompression pipe 5, it is branched into the turbine system pipe δ and the liquefaction system pipe. Turbine system piping δ
The high-pressure helium gas is branched off to the turbine valve. 1 The temperature decreases due to adiabatic expansion in turbine 3, and j
After exchanging heat with the low-temperature return gas in Ia heat exchange s7 and further lowering the temperature, it enters the tJ2 turbine 4, expands adiabatically again, lowers the temperature, and joins the low-temperature return gas in the low-pressure pipe. On the other hand, the high-pressure helium gas branched to the liquefaction system piping is
2nd heat exchanger 6° 3rd heat exchanger't,! ! ! After passing through the fourth heat exchanger 81 and the fifth heat exchanger 9 and being cooled by the low-temperature return gas, it expands to almost atmospheric pressure at the JT valve 14, partially liquefies and enters the storage tank 11, where the unliquefied gas passes through the low pressure piping and passes through the IJS heat exchanger 9. ! J4 heat exchanger 8
゜Third heat exchanger7. Second heat exchange s6. After being cooled and recovered in the first heat exchanger 5, it is returned to the compressor 1, and the liquefied liquid helium is stored in a storage tank 11.

Thus, the liquid helium stored in the storage tank 11 is cooled by low-temperature return gas guided from the liquefied gas pipe 19 to the sixth heat exchanger 10 from the reduced pressure return gas pipe, and further depressurized by the refrigeration load population valve 15. The helium gas that has been reduced in pressure and partially gasified is supplied to the refrigeration load device port after reaching the saturation temperature, and the helium gas that has evaporated under the heat load in the refrigeration load device ν is transferred to the reduced pressure return gas piping section. through the 6th
Heat exchanger 10 and cold exchanger 6. After being cooled and recovered in the first heat exchanger 5, a 1:11 decompression port is used to maintain the pressure of the refrigeration load device 1112 at a reduced pressure in helium gas at room temperature; = introduced in P2.

In order to supply liquid helium from the storage tank 11 according to the fluctuation of the load, the frozen fish loading device Mν adjusts the opening degree of the refrigeration load population valve 15 to adjust the liquid helium level in the refrigeration load device 12. is held constant. However, the final variation with respect to the variation of the refrigeration load is the storage tank 11
The liquid helium inside increases and decreases. Therefore,
Refrigerating load population valve 6 When the freezing load decreases, storage tank 1
Since the liquid level of JT valve 14.1 rises above a predetermined value, the refrigeration capacity of the refrigeration system must be reduced. There are problems in that operations such as adjusting the opening of the turbine valve 13 are complicated, and a time response delay occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of operating a cryogenic liquefaction refrigeration system that can be operated at a constant refrigeration capacity even when the refrigeration load fluctuates.

The present invention lowers the pressure of the six-component gas by a compressor to a low temperature,
.

It exchanges heat with the return gas;・□ Let it cool down, then expand it and turn it into a liquid. , 1°, yo・□・io□2. □□I: 1 In a cryogenic liquefaction refrigeration system in which the refrigerant gas from the storage tank is supplied to the refrigeration load device and is returned to the compressor inlet side after recovering the temperature of the refrigerant gas from the storage tank as low-temperature return gas, the liquid in the storage tank is It is characterized by controlling the liquid level so that it does not exceed a predetermined value, and when the liquid level in the storage tank exceeds a predetermined value due to fluctuations in the refrigeration load, the cryogenic liquid is evaporated and taken out as low-temperature return gas. By this, the liquid level in the storage tank is maintained at a predetermined value, and even if the refrigeration load fluctuates, there is no need to adjust the refrigeration capacity, and the system can be operated at a constant refrigeration capacity at all times.

Hereinafter, an example of a helium refrigeration system implementing the present invention will be described as a second example.
This will be explained using figures. In FIG. 2, the same parts as in FIG. 1 are indicated by the same reference numerals, and their explanation will be omitted. 16 is a liquid level controller for the storage tank 11, and 17 is a heater that heats the liquid helium in the storage tank 11. When the liquid level in the storage tank 11 exceeds the upper limit of the liquid level controller 16, it turns on, and when it is below the upper limit. It is configured so that it is turned off when this happens.

The refrigeration load of the refrigeration load device 112 decreases and the storage tank 1
When the liquid level of the liquid helium in the storage tank 1 rises and exceeds the upper limit value of the liquid level controller 16, the heater 17 is turned on and the liquid helium in the storage tank 11 is heated and evaporated.

The evaporated low-temperature helium gas is taken out through a low-pressure pipe, cooled and recovered, and then returned to the compressor 1 side. When the liquid level in the storage tank 11 falls below the upper limit value of the liquid level controller 16, the heater 17 is turned off and heating and evaporation of liquid helium is stopped. Therefore, since the liquid helium in the storage tank 11 is heated and evaporated to maintain the liquid level below a predetermined value at all times, even if the refrigeration load of the refrigeration load device Z changes, this will not change. There is no need to adjust the refrigeration capacity of the helium refrigeration system in response to this, and the helium refrigeration system can be operated at a constant refrigeration capacity at all times.

In the above embodiment, the cryogenic liquid in the storage tank 11 is heated and evaporated to maintain the liquid level in the storage tank 11 at all times below a predetermined value. By evaporating the liquid and returning it to the low-pressure piping field, the liquid level in the storage tank 11 can be kept below the specified value at all times.

As described above, in the present invention, the refrigerant gas pressurized by the compressor is cooled by exchanging heat with the low-temperature return gas, then expanded and liquefied, and the liquefied cryogenic liquid is sent to the refrigeration load equipment via the storage tank. In a cryogenic liquefaction refrigeration system in which the refrigerant gas from the storage tank is supplied and returned to the compressor inlet side after recovering the temperature as low-temperature return gas, the liquid level in the storage tank exceeds a predetermined value. When the liquid level in the storage tank exceeds a predetermined value due to fluctuations in the refrigeration load, the cryogenic liquid is evaporated and taken out as low-temperature return gas. Increase the freezing capacity of the cryogenic liquefaction refrigeration equipment in response to changes in cargo! i
l! ! Since there is no need to do this, the mechanism and operation can be simplified, and even if the refrigeration load fluctuates, the operation can always be performed at a constant refrigeration capacity, making stable cryogenic liquefaction refrigeration possible. I can make you do it.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a conventional cryogenic liquid refrigeration system, and FIG. 2 is a system diagram showing an example of a cryogenic liquid refrigeration system embodying the present invention.

Claims (1)

[Claims] 1. The refrigerant gas pressurized by the compressor is cooled by exchanging heat with the low-temperature return gas, then expanded and liquefied, and the liquefied cryogenic liquid is supplied to the refrigeration load equipment via the storage tank, and the refrigerant from the storage tank is A cryogenic liquefaction refrigeration system in which gas is returned to the inlet side of the compressor after temperature recovery as a low-temperature return gas, characterized in that the liquid level in the storage tank is controlled so as not to exceed a predetermined value. How to operate cryogenic liquefaction refrigeration equipment. 2. The method of operating a cryogenic liquefaction refrigeration apparatus according to claim 1, wherein the cryogenic liquid in the storage tank is heated and evaporated when the liquid level in the storage tank exceeds a predetermined value.