JP5009061B2 - Gas filling method and gas filling device - Google Patents

Description

  The present invention relates to a method and apparatus for filling a pressure vessel such as a gas cylinder with a gas such as oxygen, and more specifically, fills the pressure vessel with a gas without using a driving power device such as a booster pump or a compressor. The present invention relates to a gas filling method and a gas filling apparatus.

The method of filling a pressure vessel with gas is a technique that is generally popular. Examples of the gas filling method include a method of boosting the filling gas using a booster pump, a compressor or the like to obtain a high-pressure gas, and then transferring the high-pressure gas into the pressure vessel. Thus, in the method using a booster pump or the like, there is no suitable booster pump or the like when the filling gas is small.
In addition, when the filling gas is a combustion-supporting gas, if the combustion-supporting gas is rapidly increased in pressure, there is a risk of temperature increase and combustion associated with compression insulation, so a safety mechanism at the time of pressure increase is required.
Furthermore, when it is necessary to fill the pressure vessel with a high-purity gas, using a booster pump or the like is not preferable because the filling gas may be contaminated.

Conventionally, as a method of increasing the pressure of a low-temperature liquefied gas stored in a liquefied gas storage tank without using a booster pump and filling the pressure vessel, the liquefied gas in the liquefied gas storage tank is transferred to the pressurized tank, A method of vaporizing a part of the liquefied gas with a pressurized evaporator provided in the pressurized tank and increasing the pressure to obtain a gas higher in pressure than the liquefied gas in the liquefied gas storage tank, and then filling the high pressure gas into the pressure vessel Is disclosed (for example, see Patent Document 1).
However, in this method, when the liquefied gas is transferred to the pressurized tank, the pressurized tank is cooled with the liquefied gas to be filled. Therefore, the liquefied gas is vaporized until the pressurized tank is cooled, and loss occurs because the vaporized gas must be released. Therefore, this method is not suitable when using an expensive gas.

Further, the present inventors have studied a method of filling a pressure vessel after heating and pressurizing the liquefied filling gas with a heating gas other than the filling gas.
However, since this method may increase the pressure of the filling gas rapidly, there is a risk of combustion accompanying the rapid pressure increase when the filling gas is a combustion-supporting gas. Can not do it.
JP 2002-295996 A

  Therefore, the problem in the present invention is that it is possible to safely fill a pressure vessel even with a combustion-supporting gas without using a driving power device such as a pump, and there is almost no loss, and the filling gas is filled in the pressure vessel. It is to be able to be filled.

The gas filling method of the present invention is a gas filling method for filling a pressure vessel with a gas using a gas filling device equipped with a liquefied vaporizing tank for liquefying and vaporizing the gas, wherein the liquefied vaporizing tank is accommodated. By supplying a refrigerant into the vaporization tank jacket, the liquefaction vaporization tank is cooled, and the filling gas in the liquefaction vaporization tank is liquefied into a liquefied gas, and the total amount of the filling gas filled in the pressure vessel and A liquefaction step of calculating a required amount of liquefied gas from the pressure, a discharge step of discharging the refrigerant in the liquefied vaporization tank jacket, and supplying a heating gas into the liquefied vaporization tank jacket after the discharge step And a heating / pressurizing step for vaporizing the liquefied gas in the liquefied vaporizing tank and filling the pressure vessel, and in the warming / pressurizing step, the pressure in the pressure vessel and the liquefied vaporizing tank jacket Based on the pressure in the bets, to adjust the supply amount of the warming gas to the liquefied vaporization vessel jacket, and controlling the filling rate of the filling gas into the pressure vessel.

In the discharging step , it is preferable that the refrigerant in the liquefied vaporization tank jacket is discharged intermittently by a certain amount while confirming an increase in pressure in the pressure vessel.

  The gas filling device of the present invention is a gas filling device for filling a pressure vessel with a gas, a liquefied vaporizing tank for liquefying and vaporizing the gas, a liquefied vaporizing tank jacket containing the liquefied vaporized tank, and the pressure The required amount of liquefied gas is calculated from the total amount and pressure of the filling gas to be filled in the container, and based on the pressure in the pressure vessel and the pressure in the liquefied vaporization tank jacket, heating into the liquefied vaporization tank jacket is performed. And a control unit for adjusting a supply amount of the working gas and controlling a filling rate of the filling gas into the pressure vessel.

  It is preferable that the control unit performs control so as to intermittently discharge the refrigerant in the liquefied vaporization tank jacket by a certain amount while confirming an increase in pressure in the pressure vessel.

According to the present invention, a refrigerant is supplied into a liquefied vaporization tank jacket that encloses a liquefied vaporization tank. Since the gas is heated and vaporized by different heating gases and filled in the pressure vessel, there is no need to purge the filling gas and no loss occurs. Therefore, it is suitable when filling a pressure vessel with especially expensive gas.
In addition, the amount of heating gas supplied into the liquefied vaporization tank jacket is adjusted based on the pressure in the liquefied vaporization tank jacket, and the filling rate of the filling gas into the pressure vessel is controlled. A rapid increase in pressure in the container can be prevented, and a rapid temperature increase due to adiabatic compression of the gas can be prevented, which is suitable for a combustion-supporting gas.

"Gas filling device"
FIG. 1 is a schematic configuration diagram showing an example of the gas filling apparatus of the present invention.
The gas filling apparatus of this example includes a buffer tank 3 for storing a filling gas, a liquefied vaporizing tank 10 for liquefying and vaporizing the filling gas, and a liquefied vaporizing tank jacket that houses the liquefied vaporizing tank 10 and is integrated in an airtight structure. 11 and a control unit 29.

The buffer tank 3 includes a pipe 22, a mass flow controller 1 and an air drive valve 2 provided in the middle thereof, a filling gas supply line for supplying a filling gas to the buffer tank 3, and a pressure gauge 4. I have.
The liquefying and vaporizing tank 10 includes a pressure gauge 9 for measuring the pressure of the filling gas in the liquefied and vaporizing tank 10, and includes a pipe 23, an air drive valve 6 provided in the middle thereof, and a mass flow controller 5. It is connected to the buffer tank 3 through a line. The liquefying and vaporizing tank 10 includes a pipe 24 and an air drive valve 21 provided in the middle thereof, and is connected to the pressure vessel 20 through a filling line for filling the pressure vessel 20 with a filling gas. ing.
The mass flow controller 5 has a function of integrating the flow rate of the transferred liquefied gas.

  Furthermore, the liquefaction vaporization tank 10 is connected to the buffer tank 3 through a pipe 25 provided with a control valve 8 and an air drive valve 7 in the middle thereof. This pipe 25 is used to return the filling gas in the liquefied vaporization tank 10 to the buffer tank 3 when the pressure in the liquefied vaporization tank 10 rises for some reason, or to buffer the filled gas remaining in the system after filling. This is a return line for collecting in the tank 3.

The liquefying and vaporizing tank jacket 11 includes a pipe 26, an evaporator 15 and a solenoid valve 16 provided in the middle thereof, and a heating gas supply line for supplying a gas to be heated to the liquefying and vaporizing tank jacket 11 is provided. I have.
The liquefied vaporization tank jacket 11 includes a pipe 27 and an electromagnetic valve 17 provided in the middle thereof, and includes a refrigerant supply line for supplying a refrigerant to the liquefied vaporization tank jacket 11.
Further, the liquefying and vaporizing tank jacket 11 includes a pipe 28 and an electromagnetic valve 18 provided in the middle thereof, and includes an exhaust line for discharging the refrigerant from the liquefying and vaporizing tank jacket 11.

Moreover, the liquefied vaporization tank jacket 11 is equipped with the adjustment valve 13 and the electromagnetic valve 14 for releasing the vaporized refrigerant | coolant in air | atmosphere in parallel.
The liquefied vaporization tank jacket 11 includes a liquid level gauge 19 for measuring the liquid level of the refrigerant and a pressure gauge 12 for sensing the pressure of the refrigerant.

The control unit 29 calculates the required amount of liquefied gas from the total amount and the pressure of the filling gas that fills the pressure vessel 20.
Further, the control unit 29 adjusts the supply amount of the heating gas into the liquefied vaporization tank jacket 11 based on the pressure in the pressure vessel 20 and the pressure in the liquefied vaporization tank jacket 11, and supplies the pressure vessel 20 to the pressure vessel 20. Control the filling speed of the filling gas.
Further, the control unit 29 performs control so as to intermittently discharge the refrigerant in the liquefied vaporization tank jacket 11 by a certain amount while confirming an increase in the pressure in the pressure vessel 20.

"Gas filling method"
Next, a method (gas filling method) for filling the pressure vessel with gas using the gas filling apparatus shown in FIG. 1 will be described.
This gas filling method includes a charging step, a liquefaction step, a heating / pressurizing step, and a pressure recovery step.
In this description, an oxygen isotope gas of a combustion-supporting gas is used as the filling gas, and liquefied nitrogen is used as the refrigerant. The oxygen isotope gas is a combustion-supporting gas like ordinary oxygen and is a very expensive gas.

(Filling and filling process)
First, a process of introducing an oxygen isotope gas that is a filling gas into the buffer tank (a filling pressure filling process) will be described.
The air drive valves 2 and 6 are opened, the air drive valves 7 and 21 are closed, the mass flow controller 5 is fully opened, and the mass flow controller 1 is gradually opened to the maximum set value, whereby the buffer tank 3 and the filling gas Slowly introduce oxygen isotope gas into the supply line.
In addition, a front stage of the mass flow controller 1 is provided with a filling gas storage tank, an air separation device (not shown) for separating the air into a filling gas and other gases. The gas flow controller 1 is gradually opened because there is a possibility that the filling gas may flow or stop at once due to the opening and closing of the air drive valve 2 and disturb the gas-liquid balance of the air separation device.

Next, the pressure in the buffer tank 3 is measured by the pressure gauge 4, and when the specified pressure is reached, the mass flow controller 1 is gradually set to the set value 0 (closed), and after the set value reaches 0, the air drive valve 2 is turned on. Then, the oxygen isotope gas introduction (packing pressure filling) into the buffer tank 3 and the filling gas supply line is completed.
The specified pressure is set to be less than the pressure value of the oxygen isotope gas raw material itself.

(Liquefaction process)
Next, the process (liquefaction process) which liquefies oxygen isotope gas is demonstrated.
After the introduction of the oxygen isotope gas into the buffer tank 3 and the filling gas supply line is completed in the above filling and filling step, the pressure vessel 20 and the pipe 24 are purged with oxygen, and the air content in the filling line is removed. Remove it.
Next, the air drive valve 21 is opened, and the value measured by the pressure gauge 4 at that time is stored in a control system (not shown). The measured value (pressure value) by the pressure gauge 4 is the pressure of the oxygen isotope gas existing in the buffer tank 3 and the filling gas supply line (pipe 23), the liquefaction vaporization tank 10 and the filling line ( The pressure of the gas present in the tube 24) is indicated.
This pressure value is used to determine the end of integration of the oxygen isotope gas flow rate (filling amount of oxygen isotope gas).

  Next, the air drive valve 6 is kept open, the set value of the mass flow controller 5 is kept constant, and the flow rate of the oxygen isotope gas transferred from the buffer tank 3 to the liquefied vaporization tank 10 is made constant.

Next, the opening and closing of the electromagnetic valve 17 is controlled according to the measured value of the liquid level gauge 19 provided in the liquefied vaporization tank jacket 11, and liquefied nitrogen as a refrigerant is supplied to the liquefied vaporization tank jacket 11 up to a specified value. Note that the opening and closing of the solenoid valve 17 is controlled so that the measured value of the liquid level gauge 19 is always near the specified value.
At this time, the pressure in the liquefied vaporization tank jacket 11 is PID controlled by adjusting the pressure gauge 12 and the control valve 13 in order to release the evaporated portion of the liquefied nitrogen introduced into the liquefied vaporization tank jacket 11 to the atmosphere.

The specified value for supplying liquefied nitrogen is preferably about 70 to 90% of the volume of the liquefied vaporization tank jacket 11.
In addition, when the control valve 13 is not adjusted to sufficiently release the evaporated amount of liquefied nitrogen into the atmosphere, it is also effective to always open the electromagnetic valve 14 to increase the ability to release the evaporated component to the atmosphere.
In addition, when introducing liquefied nitrogen into the liquefied vaporization tank jacket 11, when the pressure in the liquefied vaporization tank jacket 11 reaches a specified value or more, a mechanism for temporarily interrupting the introduction of liquefied nitrogen by closing the electromagnetic valve 17 is provided. If provided, it is preferable because it is safer.

Thus, the liquefied vaporization tank 10 is cooled by filling the liquefied vaporization tank jacket 11 with liquefied nitrogen. As a result, the oxygen isotope gas is liquefied in the liquefied vaporization tank 10 and the pressure in the liquefied vaporization tank 10 decreases. Then, the oxygen isotope gas filled in the buffer tank 3 is transferred to the liquefied vaporization tank 10 through the mass flow controller 5 and liquefied.
Then, the flow rate of the oxygen isotope gas flowing through the mass flow controller 5 is integrated, and when this integrated amount reaches a predetermined value, the set value of the mass flow controller 5 is set to 0 (closed), and the air drive valves 6 and 17 are closed. To do.
Further, when the electromagnetic valve 14 is opened in order to release the liquefied nitrogen vapor to the atmosphere, it is also closed at the same time.

The integrated amount of oxygen isotope gas transferred from the buffer tank 3 to the liquefaction vaporization tank 10, that is, the predetermined value of the filling amount is calculated based on the following equation (1).
(P2 + 0.1013) × (V1 + V2 + V3) /0.1013− (P1 + 0.1013) × (V1 + V2 + V3) /0.1013 (1)
However, in Formula (1), P1 is the pressure value which the pressure gauge 4 shows at the time of the start of liquefaction, the pressure of the oxygen isotope gas which exists in the buffer tank 3 and the filling gas supply line (pipe 23), and liquefaction The pressure of the gas which exists in the vaporization tank 10 and a filling line (pipe 24) is represented. P2 is the target pressure for filling the pressure vessel 20, V1 is the volume of the liquefied vaporization tank 10, V2 is the volume of the pressure vessel 20, and V3 is the volume + α of the tube 24 connecting the liquefied vaporization tank 10 and the pressure vessel 20. .

  The first term of the above formula (1) is the volume at the standard pressure (0 ° C., 1 atm) as the volume of the liquefied vaporization tank 10 under the filling target pressure + the volume of the pressure vessel 20 + the volume of the tube 24 + α. It is a numerical value converted into. On the other hand, the second term is a numerical value obtained by subtracting the volume of the oxygen isotope gas contained in the tube 24 and the liquefied vaporization tank 10 before the start of liquefaction.

  In addition, in V3, the value obtained by adding α (volume) to the volume of the filling pipe is because the oxygen isotope gas may slightly return to the buffer tank 3 in the heating and pressurizing process described later. This is because the shortage needs to be corrected.

Further, when the temperature T around the gas filling device can be measured, the above formula (1) is changed to the following formula (2) to thereby more accurately define the integrated amount of oxygen isotope gas. The value can be determined.
[(P2 + 0.1013) × (V1 + V2 + V3) /0.1013− (P1 + 0.1013) × (V1 + V2 + V3) /0.1013] × T / 273 (2)
T in the above formula is a value measured at the start of the liquefaction process.

Next, the electromagnetic valve 18 is opened, and the liquefied nitrogen filled in the liquefied vaporization tank jacket 11 is discharged.
At this time, as the amount of liquefied nitrogen in the liquefied vaporization tank jacket 11 decreases, the oxygen isotope gas liquefied in the liquefied vaporization tank 10 is vaporized and measured by the pressure gauge 9. There is a danger that the pressure value of the oxygen isotope gas in the inside will rise rapidly.
Therefore, as shown in FIG. 2, the liquefied nitrogen is discharged intermittently by a certain amount of the liquefied nitrogen filled in the liquefied vaporization tank jacket 11. At the same time, the pressure of the oxygen isotope gas is determined by checking the pressure of the oxygen isotope gas with the pressure gauge 9 every time a certain amount of liquefied nitrogen is discharged in order to prevent sudden pressure increase of the oxygen isotope gas. When the pressure rises above the pressure, the discharge of liquefied nitrogen is temporarily interrupted, and the discharge of liquefied nitrogen is resumed after the pressure of the oxygen isotope gas drops below the specified pressure.

Next, when the liquid level of the liquefied nitrogen in the liquefied vaporization tank jacket 11 falls to 1% or less of the volume of the liquefied vaporization tank jacket 11, the electromagnetic valve 18 is closed and the discharge of liquefied nitrogen is terminated.
The interval at which the liquefied nitrogen is discharged is preferably about 10% of the total amount of oxygen isotope gas filled in the liquefied vaporization tank 10, but safety can be improved by discharging a smaller amount. it can.

(Heating / Pressurizing process)
Next, a process of heating / pressurizing the oxygen isotope gas (heating / pressurizing process) will be described.
When the above liquefaction process is completed, the electromagnetic valve 16 is opened, and liquefied nitrogen (heating gas) vaporized by the evaporator 15 is transferred to the liquefied vaporization tank jacket 11 and released into the atmosphere via the electromagnetic valve 13. To heat the liquefied vaporization tank 10. By heating the liquefied vaporization tank 10, the oxygen isotope gas in the tank is vaporized and the pressure is increased.

Then, the vaporized oxygen isotope gas is transferred to the pressure vessel 20 and filling is started.
Here, according to the measured value of the pressure gauge 12 and the measured value of the pressure gauge 9, the opening and closing of the electromagnetic valve 16 is controlled to adjust the supply amount of the heating gas into the liquefied vaporization tank jacket 11. The filling gas filling rate to 20 is controlled.
That is, when the measured value of the pressure gauge 12 (pressure value in the liquefied vaporization tank jacket) becomes higher than a predetermined value, the electromagnetic valve 16 is closed, the transfer of the heating gas is stopped, and the liquefaction vaporization tank 10 is stopped. Reduce the heat exchange capacity. On the other hand, when the measured value of the pressure gauge 12 becomes lower than the predetermined value, the electromagnetic valve 16 is opened, the transfer of the heating gas is resumed, and the liquefied nitrogen continuously vaporized into the liquefied vaporization tank jacket 11. And the liquefied vaporization tank 10 is heated to increase the heat exchange capacity.

In this heating / pressurizing step, both the pressure gauge 9 and the pressure gauge 12 are PID controlled by adjusting the control valve 13.
The PID control of the pressure gauge 9 and the pressure gauge 12 is a high selector, and priority is given to the one with the larger open output.
In addition, by making the set value of PID control of the pressure gauge 12 constant, the pressure in the liquefied vaporization tank jacket 11 is prevented from rising abnormally.

On the other hand, the set value of PID control of the pressure gauge 9 is increased to the filling pressure by gradually increasing the slope in several stages.
In this way, by gradually increasing the set value of PID control of the pressure gauge 9, the flow rate of the heated gas (nitrogen gas) passing through the liquefied vaporization tank jacket 11 is adjusted by the control valve 13, and the oxygen isotope gas is adjusted. Can be gradually increased.
FIG. 3 shows an example in which the PID control set value of the pressure gauge 9 is divided into three stages, and the oxygen isotope gas is gradually increased. In this example, since the liquefied vaporization tank jacket 11 is not sufficiently warmed at the start of pressurization, the pressure increase speed is slowed down (first stage). At the end of the pressurization, most of the oxygen isotope gas is vaporized, so the pressurization speed is slowed down (third stage).

In addition, as a safety mechanism in the heating / pressurizing process, the value of the pressure gauge 9 is PID controlled by the control valve 8. The set value of PID control by the control valve 8 is preferably a value obtained by adding β to the filling pressure of the filling gas into the pressure vessel 20, and this added amount β is preferably a value of about 1 to 5% of the filling pressure. .
Immediately before opening the regulating valve 8, the air drive valve 7 is opened, and the excess of the pressure in the liquefied vaporization tank 10 (the excess of vaporized oxygen isotope gas) is returned to the buffer tank 3.
Furthermore, by adjusting the control valve 8, PID control regarding the rate of change of the pressure gauge 9 is simultaneously performed, and this control is used as a high selector so that the oxygen isotope gas can be dealt with even when the pressure is rapidly increased. Can further increase safety.

  This heating / pressurizing step ends when the measured value of the pressure gauge 9 reaches the filling pressure of the filling gas into the pressure vessel 20. That is, at this time, the filling of the oxygen isotope gas into the pressure vessel 20 is finished.

(Pressure recovery process)
Next, a process of recovering the filling gas remaining in each line in the buffer tank (pressure recovery process) will be described.
The main valve (not shown) of the pressure vessel 20 is closed, the air drive valve 7 and the control valve 8 are opened, and the oxygen isotope gas (the excess thereof) is recovered in the buffer tank 3. The oxygen isotope gas recovered in the buffer tank 3 can be reused when the filling gas is filled next time.

  Next, after the filling gas remaining in each line such as the filling gas supply line, the transfer line, the filling line, and the return line is collected in the buffer tank 3, the air driving valve 21 is closed and the pressure vessel 20 is taken out.

  In this pressure recovery step, the value of the pressure gauge 9 is PID controlled by the control valve 8. At this time, the oxygen isotope gas is prevented from being rapidly transferred to the buffer tank 3 by gradually lowering the set value of the PID control of the pressure gauge 9.

It is a schematic block diagram which shows an example of the gas filling apparatus used for the gas filling method of this invention. It is a graph which shows the process in which the used liquefied nitrogen is discharged | emitted from a liquefied vaporization tank jacket in the liquefaction process of the gas filling method of this invention. It is a graph which shows the case where the inclination of the setting value of control regarding the PID control of a pressure gauge is divided into three steps in the heating / pressure increase process of the gas filling method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mass flow controller, 2 ... Air drive valve, 3 ... Buffer tank, 4 ... Pressure gauge, 5 ... Mass flow controller, 6 ... Air drive valve, 7 ... Air drive Valves, 8 ... Control valve, 9 ... Pressure gauge, 10 ... Liquefaction vaporization tank, 11 ... Liquefaction vaporization tank jacket, 12 ... Pressure gauge, 13 ... Control valve, 14 ... -Solenoid valve, 15 ... Evaporator, 16 ... Solenoid valve, 17 ... Solenoid valve, 18 ... Solenoid valve, 19 ... Liquid level gauge, 20 ... Pressure vessel, 21 ... -Air drive valve, 29 ... control part.

Claims (4)

A gas filling method for filling a pressure vessel with gas using a gas filling device equipped with a liquefied vaporization tank for liquefying and vaporizing gas,
By supplying a refrigerant into the liquefied vaporization tank jacket in which the liquefied vaporization tank is accommodated, the liquefied vaporization tank is cooled, and the filling gas in the liquefied vaporization tank is liquefied to become a liquefied gas, and the pressure A liquefaction step of calculating the amount of liquefied gas required from the total amount and pressure of the filling gas filled in the container ;
A discharge step of discharging the refrigerant in the liquefied vaporization tank jacket ;
After the discharging step , by supplying a heating gas into the liquefied vaporization tank jacket, the liquefied vaporization tank is vaporized and filled into the pressure vessel by a heating / pressurizing process,
In the heating / pressurizing step, based on the pressure in the pressure vessel and the pressure in the liquefied vaporization tank jacket, the supply amount of the heating gas into the liquefied vaporization tank jacket is adjusted, and the pressure vessel is supplied. A gas filling method comprising controlling a filling speed of a filling gas. 2. The gas filling method according to claim 1, wherein in the discharging step , the refrigerant in the liquefied vaporization tank jacket is intermittently discharged by a certain amount while confirming an increase in pressure in the pressure vessel. A gas filling device for filling a pressure vessel with gas,
A liquefied vaporization tank for liquefying and vaporizing gas, a liquefied vaporization tank jacket containing the liquefied vaporized tank, a total amount of filling gas filled in the pressure vessel, and a required liquefied gas amount are calculated from the pressure vessel. A control unit that adjusts the supply amount of the heating gas into the liquefied vaporization tank jacket based on the internal pressure and the pressure in the liquefied vaporization tank jacket, and controls the filling rate of the filling gas into the pressure vessel And a gas filling device.   The said control part is controlled to discharge | emit the refrigerant | coolant in the said liquefaction vaporization tank jacket intermittently by a fixed amount, confirming the raise of the pressure in the said pressure vessel. Gas filling device.

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