JPH0633860B2 - Ultra low temperature liquefied gas supply method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for supplying ultra-low temperature liquefied gas from a storage tank under pressure to a container such as a cylinder or a customer by a liquefied gas pressure pump.

[Conventional technology]

The conventional ultra-low temperature liquefied gas supply method will be described with reference to the piping system diagram of FIG. 2. The valves 1, 2, 3 and 4 are opened, and the ultra-low temperature liquefied gas in the ultra-low temperature liquefied gas storage tank 5 is used to pump the liquefied gas pressurizing pump 6. Is pre-cooled in order to suppress vaporization of the liquefied gas in the pump 6 during supply, but this is done manually.

That is, the liquefied gas pressurizing pump 6 is started by observing the amount of the liquefied gas ejected from the valves 2 and 4 when the precooling of the liquefied gas pressurizing pump 6 is completed, and the valves 2 and 4 are closed to close the ultra-low temperature liquefied gas. Is sent to the vaporizer 7 and is filled in a container 8 such as a cylinder as high-pressure vaporized gas.

[Problems to be Solved by the Invention]

However, in the case of this method, it is difficult to confirm the precooling completion of the liquefied gas pressurizing pump 6 because the valve operation is manually performed, and it is difficult to confirm the precooling of the liquefied gas pressurizing pump 6. Consuming a large amount of water and causing cavitation due to insufficient precooling after activation of the liquefied gas pressurizing pump 6 or temperature rise during operation of the pump 6 despite the fact that precooling was performed, causing the pump to run dry. As a result, for example, in a liquefied oxygen pressurizing pump, there is a risk of causing an ignition and explosion accident due to overheating of the gland portion of the pump, and in order to prevent this, it is always judged visually to prevent it.

Therefore, the present invention automatically performs in-system purging, pre-cooling and starting of the liquefied gas pressurizing pump to prevent cavitation generated in the liquefied gas pressurizing pump and idling resulting therefrom, ensuring safety and saving labor. It is an object of the present invention to provide an ultra-low temperature liquefied gas supply method for achieving the above.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides an ultra-low temperature liquefied gas supply method for supplying ultra-low temperature liquefied gas from an ultra-low temperature liquefied gas storage tank to a container such as a cylinder under pressure by a liquefied gas pressure pump. The temperature measuring sensor provided detects the temperature inside the liquefied gas pressurizing pump, and the detected temperature is measured by the temperature indicator setting device that sets the precooling completion temperature and the cavitation generation temperature in advance. When the arrival at the precooling completion temperature is detected and transmitted to the sequence controller, the sequence controller, when receiving the precooling completion temperature reaching signal, precooling end operation of the liquefied gas pressurizing pump
A precooling completion sequence including activation of the pump and valve operation for liquid transfer is performed, and when the cavitation generation temperature reaching signal is received, liquefied gas pressurization pump is stopped, valve operation for purging is included, and precooling start of the pump is included. It is characterized by performing a pump pre-cooling sequence.

[Action]

Therefore, when supplying ultra-low temperature liquefied gas to a container such as a cylinder under pressure, when the liquefied gas pressure pump is cooled to a predetermined temperature, the temperature inside the liquefied gas pressure pump detected by the temperature measurement sensor is indicated as a temperature. When the temperature is measured by the setting device and this temperature reaches the preset pre-cooling completion temperature, the pre-cooling completion temperature reaching signal is sent to the sequence controller, and the sequence controller receiving this pre-cooling completion temperature reaching signal causes the liquefied gas The precooling of the pressurizing pump is completed, the pump is started, and the valve for liquid feeding is operated to start the supply of the ultra-low temperature liquefied gas to the container such as the cylinder.

If the temperature inside the liquefied gas pressure pump rises during the pressurized supply of ultra-low temperature liquefied gas to a container such as a cylinder, the liquefied gas pressure detected by the temperature measurement sensor and measured by the temperature indicator When the temperature inside the pressure pump reaches the preset cavitation generation temperature, it sends a cavitation generation temperature arrival signal to the sequence controller, and the sequence controller that receives this cavitation generation temperature arrival signal operates the liquefied gas pressurization pump. At the same time as stopping, the precooling gas purge valve is operated to start reprecooling of the pump.

When the liquefied gas pressurizing pump is cooled to the precooling completion temperature by this re-precooling, the liquefied gas pressurizing pump is started by the sequence controller, and at the same time, the liquid feeding valve is operated to transfer it to a container such as a cylinder. The supply of the ultra-low temperature liquefied gas is restarted.

〔Example〕

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

When the automatic liquefaction pressurizing switch of the electric instrumentation panel 10 or the remote electric instrumentation panel 11 is turned on, the sequence controller 12 is activated and the automatic valves 13, 14 and 15 are opened, and the ultra-low temperature liquefied gas storage tank 16 liquefies the ultra-low temperature liquefaction. Gas is supplied into the liquefied gas pressurizing pump 17 through the automatic valve 13, and the inside of the system between the automatic valve 18 and the automatic valve 19 for liquid transfer is purged for 15 seconds.

After being purged for 15 seconds, the automatic valve 14 is closed and at the same time the automatic valve 18 is opened, and the vaporized gas passing through the automatic valve 18 reaches the upper portion of the ultra low temperature liquefied gas storage tank 16 and the storage tank 16
The liquid surface of the ultra-low temperature liquefied gas inside is pressurized to create a supercooled liquid state.

During this period, the pump 17 is pre-cooled by the gas purged from the automatic purge valve 15 via the liquefied gas pressurizing pump 17.

The temperature inside the liquefied gas pressurizing pump 17 depends on the pump 17
The temperature is measured by the temperature measuring sensor 20 provided in the immediate vicinity of the discharge side and the temperature is measured by the temperature instruction setting device 21 provided in the electric instrumentation board 10.

The pre-cooling completion temperature and the cavitation generation temperature are preset in the temperature instruction setting device 21, and the pre-cooling completion temperature and the cavitation generation temperature that are set by the temperature instruction setting device 21 are compared and measured. When the set temperature reaches these set temperatures, the precooling completion temperature reaching signal and the cavitation generation temperature reaching signal are transmitted to the sequence controller 12. The precooling completion temperature is set to, for example, 150 ° C. to −120 ° C., and the cavitation generation temperature is set to a temperature that is higher than the precooling completion temperature by several 10 ° C., for example.

Therefore, the automatic valve 15 is opened for purging until the temperature in the liquefied gas pressurizing pump 17 measured by the temperature instruction setting device 21 reaches the precooling completion temperature, and the pump 1
Pre-cooling in 7 continues.

When the temperature in the liquefied gas pressurizing pump 17 reaches the precooling completion temperature, the temperature instruction setting device 21 transmits a precooling completion temperature arrival signal to the sequence controller 12, and the sequence controller 12 reaches the precooling completion temperature. Upon receiving the signal, the sequence controller 12 completes the precooling of the liquefied gas pressurizing pump 17 and starts the pump 17 by the precooling completion sequence.

After the liquefied gas pressurizing pump 17 is started, 15 seconds have passed,
The sequence controller 12 closes the automatic purging valve 15 and opens the liquid feeding automatic valve 19 to start the supply of the ultra low temperature liquefied gas to the gas feeding vaporizer 22 or the ultra low temperature liquefied gas filling facility 23. .

In this way, by comparing the temperature on the discharge side of the liquefied gas pressurizing pump 17 and the precooling completion temperature with the temperature instruction setting device 21, a precooling completion temperature reaching signal is sent to the sequence controller 12, and the sequence controller 12 causes The pre-cooling of the liquefied gas pressurizing pump 17 is completed, the pump 17 is started, the automatic valve 15 for purging is closed, and the automatic valve 1 for liquid transfer 1
Since 9 is opened and the supply of ultra low temperature liquefied gas is started,
The liquefied gas pressurizing pump 17 can be surely precooled without waste of ultra-low temperature liquefied gas, and cavitation due to insufficient precooling of the pump 17 can be prevented.

The ultra low temperature liquefied gas discharged from the liquefied gas pressurizing pump 17 is supplied to the gas feed vaporizer 22 or the ultra low temperature liquefied gas filling facility 2
It is sent to 3. The ultra-low temperature liquefied gas sent to the gas sending vaporizer 22 becomes vaporized gas in the gas sending vaporizer 22, is sent to the high pressure gas filling facility 24, and is sent to the high pressure gas container 2 such as a cylinder.
5 is filled. Moreover, the ultra-low temperature liquefied gas sent to the ultra-low temperature liquefied gas filling facility 23 is filled in an ultra-low temperature liquefied gas container (not shown).

The high-pressure gas filling equipment 24 and the ultra-low temperature liquefied gas filling equipment 2
The switching with 3 is performed by automatic or manual operation of the switching valves 26 and 27.

Next, when the temperature inside the pump 17 rises while the liquefied gas pressurizing pump 17 continues to operate, the temperature inside the pump 17 is detected by the temperature measuring sensor 20, and the detected temperature is indicated by a temperature instruction. When the temperature is measured by the setting device 21 and this temperature reaches the cavitation generation temperature set in the temperature instruction setting device 21, the temperature instruction setting device 21 transmits a cavitation generation temperature arrival signal to the sequence controller 12.

When the sequence controller 12 receives the cavitation generation temperature reaching signal, the pump re-precooling sequence of the sequence controller 12 stops the liquefied gas pressurizing pump 17, closes the automatic liquid feeding valve 19, and automatically purges the gas. The valve 15 is opened and the re-precooling of the pump 17 is started.

When the liquefied gas pressurizing pump 17 is cooled to the pre-cooling completion temperature by this re-pre-cooling, the automatic purge valve 1 is purged by the pre-cooling completion sequence of the sequence controller 12 similar to the above.
5 is closed, the liquefied gas pressurizing pump 17 is started, the automatic valve 19 for liquid transfer is opened, and the supply of the ultra-low temperature liquefied gas is restarted.

In this way, by comparing the temperature on the discharge side of the liquefied gas pressurizing pump 17 and the cavitation generation temperature with the temperature instruction setting device 21, the cavitation generation temperature reaching signal is sent to the sequence controller 12, and the sequence controller 1
2, the operation of the liquefied gas pressure pump 17 is stopped,
Since the automatic valve 19 for liquid transfer is closed and the automatic valve 15 for barge is opened for re-precooling, even if the temperature inside the liquefied gas pressurizing pump 17 rises during the operation of the liquefied gas pressurizing pump 17, cavitation is increased. It is possible to stop the operation of the pump 17 before the occurrence of, and it is possible to prevent idling due to cavitation.

Furthermore, after stopping the operation of the liquefied gas pressure pump 17,
Since re-precooling is subsequently started, the ultra-low temperature liquefied gas can be automatically supplied again while ensuring safety and saving labor.

As described above, the sequence controller 12 receives the precooling completion temperature reaching signal and the cavitation generation temperature reaching signal from the temperature instruction setting device 21, and performs the precooling completion sequence and the pump reprecooling sequence by temperature control. However, in addition, the following pump stop sequence and pump restart sequence by pressure control are also performed.

That is, the vaporized gas discharged from the liquefied gas pressurizing pump 17, vaporized by the gas vaporizer 22 and sent to the high pressure gas filling facility 24 is pressurized by the pressure sensors 28 and 29.
The pressure inside 5 is detected, and the high pressure gas container 25 is automatically filled by switching the automatic valves 30 and 31. On the other hand, the ultra-low temperature liquefied gas sent to the ultra-low temperature liquefied gas filling equipment 23 is automatically controlled by the liquid level detection limit switches 32 and 33.
4, 5 and 35 are switched to automatically fill an ultra-low temperature liquefied gas container (not shown).

When the pressure in the piping of the filling system rises above the set pressure during these fillings, a pump stop signal from the pressure sensors 36 and 37 is received, and liquefaction is automatically performed by the pump stop sequence of the sequence controller 12. The operation of the gas pressurizing pump 17 is stopped, and at the same time as the stop, the automatic valves 13, 1
8 and 19 are closed, the automatic purge valve 15 is opened, the internal system pressure between the automatic valve 13 and the automatic valve 18 and the automatic valve 13 for liquid delivery is released from the automatic valve 13, and the filling is interrupted.

When the pressure in the piping of the filling equipment 23, 24 system becomes equal to or lower than the set value, a pump restart signal from the pressure sensors 36, 37 is received, and the automatic valve 13, automatically by the pump restart sequence of the sequence controller 12, 18 is opened, precooling of the liquefied gas pressurizing pump 17 is started, the above-described precooling operation is performed, and the ultra low temperature liquefied gas is supplied again.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention liquefies the ultra low temperature liquefied gas in the ultra low temperature liquefied gas storage tank by pressurizing and supplying it to a container such as a cylinder by the liquefied gas pressure pump by using a temperature measurement sensor provided on the discharge side of the liquefied gas pressure pump. The temperature inside the gas pressurizing pump is detected, and the detected temperature is measured by a temperature indicator setting device that sets the precooling completion temperature and the cavitation generation temperature in advance. The sequence controller performs a precooling completion sequence including precooling ending operation of the liquefied gas pressurizing pump, starting of the pump, and valve operation for liquid transfer when the precooling completion temperature reaching signal is received. When the cavitation generation temperature arrival signal is received, the liquefied gas pressure pump is stopped,
Since the pump re-precooling sequence including the valve operation for the barge and the start of precooling of the pump is performed, the liquefied gas pressurizing pump can be surely precooled without waste of ultra-low temperature liquefied gas, and the precooling of the pump is insufficient. The occurrence of cavitation can be prevented, and even if the temperature inside the liquefied gas pressure pump rises during the operation of the pump, the operation of the pump can be stopped before the occurrence of cavitation. In addition, it is possible to prevent re-cooling and to automatically supply the ultra-low temperature liquefied gas again while ensuring safety and saving labor by stopping the operation of the liquefied gas pressurizing pump and continuing the re-precooling. it can.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing an embodiment of an ultra-low temperature liquefied gas supply method according to the present invention, and FIG. 2 is a piping system diagram of a conventional ultra-low temperature liquefied gas supply method. 12 ... Sequence controller, 13, 14, 18 ... Automatic valve, 15 ... Automatic valve for purging, 16 ... Ultra low temperature liquefied gas storage tank, 17 ... Liquefied gas pressurizing pump, 19 ... For liquid transfer Automatic valve, 20 ... Temperature measuring sensor, 21 ... Temperature indication setting device, 22 ... Gas vaporizer, 23 ... Ultra low temperature liquefied gas filling facility, 24 ... High pressure gas filling facility, 25 ... High pressure gas container

Claims (1)

[Claims] 1. A method for supplying ultra-low temperature liquefied gas from an ultra-low temperature liquefied gas storage tank to a container such as a cylinder under pressure by means of a liquefied gas pressure pump, in which a temperature measurement is provided on the discharge side of the liquefied gas pressure pump. The temperature inside the liquefied gas pressurizing pump is detected by the sensor, and the detected temperature is measured by the temperature instruction setter that sets the precooling completion temperature and the cavitation generation temperature in advance, and the arrival at each of the set temperatures is detected. And transmits to the sequence controller, the sequence controller, when receiving the precooling completion temperature reaching signal, terminates the precooling of the liquefied gas pressurizing pump, starts the pump,
A precooling completion sequence including a valve operation for liquid transfer is performed, and when a cavitation generation temperature reaching signal is received, a liquefied gas pressurizing pump is stopped, a valve operation for purging is performed, and a pump reprecooling sequence including precooling start of the pump is performed. A method for supplying ultra-low temperature liquefied gas, which is characterized in that it is performed.