Gas Supply System

Abstract

To provide a gas supply system capable of adjusting inner pressure corresponding to a change in the inner pressure of a pressure container.SOLUTION: The gas supply system as a system for supplying gas from gas-liquid mixed fluid stored in a pressure container to an object to be supplied includes a first line connected to a layer of gas in the pressure container, a second line connected to a layer of liquid in the pressure container and having a vaporizer in the middle and joined with the first line on the downstream side of the vaporizer, a valve in the second line between the pressure container and the vaporizer, a pressure gauge for obtaining a pressure in the pressure container, and a control device. The control device receives pressure information from the pressure gauge, and when the inner pressure of the pressure container falls below a predetermined value, performs control to set the valve into the opened state and supply the gas vaporized by the vaporizer in the second line from the first line to the pressure container.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to gas supply systems. [Background technology]

[0002] Patent Document 1 discloses the installation of a second tank equipped with an adsorbent as a means of effectively using the boil-off gas from the cryogenic tank without venting it outside the system. Here, it discloses that a back pressure valve is installed between the first and second tanks, and by maintaining the pressure on the first tank side as high as possible and reducing the amount of boil-off, the amount released into the atmosphere from the second tank is suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-308844 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional technology such as that disclosed in Patent Document 1, the internal pressure of the tank changes depending on the amount of heat that enters, making it difficult to respond to changes in the internal pressure.

[0005] In view of the above problems, an object of the present disclosure is to provide a gas supply system that can adjust the internal pressure in response to changes in the internal pressure of a pressure vessel. [Means for solving the problem]

[0006] The present application discloses a gas supply system that supplies gas to a supply target from a gas-liquid mixed fluid stored in a pressure vessel, comprising: a first line connected to a gas layer in the pressure vessel; a second line connected to a liquid layer in the pressure vessel, having a vaporizer midway and merging with the first line downstream of the vaporizer; a valve arranged on the second line between the pressure vessel and the vaporizer; a pressure gauge that measures the pressure inside the pressure vessel; and a control device, wherein the control device receives pressure information from the pressure gauge, and when the internal pressure of the pressure vessel falls below a predetermined value, opens the valve and controls the supply of gas vaporized by the vaporizer on the second line from the first line to the pressure vessel.

[0007] The present application also provides a gas supply system for supplying gas to a target object from a gas-liquid mixed fluid stored in a pressure vessel, the gas supply system comprising: a first line connected to a gas layer in the pressure vessel; a second line connected to a liquid layer in the pressure vessel, having a vaporizer midway and merging with the first line downstream of the vaporizer; a valve arranged on the second line between the pressure vessel and the vaporizer; a pressure gauge for measuring the pressure inside the pressure vessel; and a control device, wherein the control device receives pressure information from the pressure gauge, and when the internal pressure of the pressure vessel exceeds a predetermined value, closes the valve and controls the supply of gas from the first line to the target object.

[0008] In the gas supply system, the first line may also be provided with a valve, the opening and closing of which may be controlled by the control device. [Effects of the Invention]

[0009] According to the present disclosure, the internal pressure of the pressure vessel can be adjusted in response to changes in the internal pressure. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a conceptual diagram of the configuration of a gas supply system 10. [Figure 2] FIG. 2 is a diagram showing the flow of control S1. [Figure 3] FIG. 3 is a diagram showing the flow of control S10. [Figure 4]FIG. 4 is a diagram showing the flow of control S20. [Figure 5] FIG. 5 is a diagram showing the flow of control S30. [Figure 6] FIG. 6 is a diagram showing the flow of control S40. [Figure 7] FIG. 7 is a diagram showing the flow of control S101. [Figure 8] FIG. 8 is a diagram showing the flow of control S110. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. Gas supply system configuration 1 conceptually illustrates the configuration of one embodiment of a gas supply system 10. This gas supply system 10 is a system that supplies a cryogenic fluid, such as liquid nitrogen or liquid oxygen, stored in a gas-liquid mixed state in a pressure vessel to a supply target in a gaseous state.

[0012] The gas supply system 10 comprises a pressure vessel 11 inside which a cryogenic fluid is stored in a gas-liquid mixed state. The pressure vessel 11 is equipped with a first line 12 of a piping system which is connected to a gas layer of the stored cryogenic fluid and serves as a flow path for extracting and discharging the gas, and a second line 13 of a piping system which is connected to a liquid layer of the stored cryogenic fluid and serves as a flow path for extracting and discharging the cryogenic fluid in liquid form. Therefore, the first line 12 is connected to the top of the pressure vessel 11, and the second line 13 is connected to the bottom of the pressure vessel 11. Furthermore, the first line 12 and the second line 13 join midway (at location G) and are connected to the supply target 1.

[0013] The pressure vessel 11 is equipped with a safety valve 14 that releases gas from inside the pressure vessel 11, and a pressure gauge 15 that measures the pressure (internal pressure) inside the pressure vessel 11. The pressure gauge 15 is configured to be able to transmit its measurement value as a signal to a control device 20, which will be described later.

[0014] A switching valve 12a that switches between allowing and prohibiting the flow of fluid is disposed midway along the first line 12, and a switching valve 13a that switches between allowing and prohibiting the flow of fluid is disposed midway along the second line 13. These switching valves 12a and 13a are solenoid valves that are configured to be able to switch between an open state (a state in which the flow of fluid is allowed) and a closed state (a state in which the flow of fluid is prohibited) in response to a signal from a control device 20, which will be described later.

[0015] Furthermore, second line 13 is provided with vaporizer 16 between switching valve 13a and confluence G. Vaporizer 16 is a device that heats and vaporizes the liquid cryogenic fluid flowing in second line 13. There are no particular limitations on the vaporizer 16, and any known vaporizer can be used as long as it can heat the liquid flowing in the piping so as to vaporize it.

[0016] The control device 20 acquires pressure information from the pressure gauge 15, performs calculations, and issues commands to the switching valves 12a and 13a based on the calculation results to control the flow of fluid and maintain an appropriate internal pressure in the pressure vessel 11. Such a control device 20 is equipped with a CPU (Central Processing Unit), which is a processor that performs calculations, a RAM (Random Access Memory) that functions as a working area, a ROM (Read-Only Memory) that functions as a recording medium, a receiving unit that is an interface to which devices are connected and which receives information from the device into the control device 20, and a transmitting unit that is an interface to which devices are connected and which sends information from the control device 20 to the outside.

[0017] The control device 20 stores a program that processes information from each device to determine and operate the device. In the control device 20, the CPU, RAM, and ROM as hardware resources cooperate with the program. Specifically, the CPU controls the device by executing the computer program recorded in the ROM in the RAM that functions as a work area. Information acquired or generated by the CPU is stored in the RAM. In addition, a separate recording medium may be provided inside or outside the control device 20, and a program and various data may be recorded therein. Such a control device 20 can typically be configured by a computer.

[0018] 2. Internal Pressure Control of Pressure Vessel As an example, the internal pressure control S1 of the pressure vessel by the gas supply system 10 will be described. This control is advanced by the control device 20 calculating the pressure value acquired by the pressure gauge 15 and controlling the switching valves 12a and 13a. Fig. 2 shows the flow of the internal pressure control S1 of the pressure vessel.

[0019] As a prerequisite, regarding the pressure of the pressure vessel 11, let the pressure lower limit specified value be Pl, the pressure upper limit specified value be Pu, the safety valve setting value be Ps, and the internal pressure of the pressure vessel be P. Here, Pl is the pressure specified as the minimum required to send gas to the supply target 1, Pu is the maximum pressure that the pressure vessel 11 can withstand (not the pressure at which the pressure vessel 11 ruptures, but the maximum pressure from the perspective of gas supply control), Ps is the pressure at which the safety valve 14 operates, and these are set as predetermined values, and the relationship Pl < Pu < Ps holds. P is the pressure inside the pressure vessel 11 obtained by the pressure gauge 15 and varies depending on the situation.

[0020] As can be seen from Fig. 2, the internal pressure control S1 of the pressure vessel includes each process of the measurement S2 of P, the valve control calculation P3 based on the value of P, and the valve control S4.

[0021] In the measurement S2 of P, the internal pressure of the pressure vessel 11 is obtained by the pressure gauge 15, and the measured value information is transmitted to the control device 20 as a signal. In the valve control operation S3 based on the value of P, the control device 20 performs an operation based on the pressure value obtained in the measurement S2 of P, and determines commands (valve control) for the switching valves 12a and 13a. In the valve control S4, commands are given to the switching valves 12a and 13a based on P determined in the valve control operation S3 based on the value of P. The specific open / closed states of the switching valves 12a and 13a in the valve control S4 differ depending on the value of P, and the flow is shown in FIGS. 3 to 6.

[0022] 2.1. When P ≥ Ps When P ≥ Ps, it proceeds by the control S10 as shown in FIG. 3. This is the case where the internal pressure of the pressure vessel 11 is equal to or higher than the operating pressure of the safety valve 14, and the safety valve 14 is set to the open state (process S11), and gas is released from the pressure vessel 11 to lower the internal pressure of the pressure vessel 11. Then, P is measured again by the pressure gauge 15 (process S12), and it is determined by the control device 20 that P ≥ Ps (process S13). If it is Yes in process S13, since the internal pressure is still high, the open state of the safety valve is maintained (process S14), and it returns to process S12. On the other hand, if it is No in process S13, since the internal pressure has become lower than Ps, the safety valve is set to the closed state (process S15), and it returns to the measurement S2 of P above.

[0023] 2.2. When Pl ≤ P ≤ Pu When Pl ≤ P ≤ Pu, it proceeds by the control S20 as shown in FIG. 4. This is the case where the internal pressure of the pressure vessel 11 is between the lower pressure specified value Pl and the upper pressure specified value Pu, and there is no need to actively vary the internal pressure of the pressure vessel 11. At this time, the switching valve 12a (valve 1) of the first line 12 is set to the closed state, and the switching valve 13a (valve 2) of the second line 13 is set to the open state (process S21). Thereby, the fluid in the liquid state flows from the pressure vessel 11 through the second line 13, is vaporized in the vaporizer 16, and gas is supplied to the supply target 1. Then, it returns to the measurement S2 of P above.

[0024] 2.3. When Pu < P < Ps When Pu < P < Ps, it proceeds by control S30 as shown in Fig. 5. This is the case where the internal pressure of the pressure vessel 11 has not reached the operating pressure Ps of the safety valve 14 but exceeds the pressure upper limit specified value Pu. At this time, the switching valve 12a of the first line 12 is opened, and the switching valve 13a of the second line 13 is closed (process S31). Thereby, the fluid in the gaseous state flows from the pressure vessel 11 through the first line 12 and gas is supplied to the supply target 1. Therefore, the internal pressure of the pressure vessel 11 is reduced. After that, P is measured again by the pressure gauge 15 (process S32), and it is determined by the control device 20 that P = Pl (process S33). If it is No in process S33, since the internal pressure of the pressure vessel 11 has not reached the pressure lower limit specified value Pl, the switching valves 12a and 13a maintain the state of process S31 (process S34), and it returns to process S32. On the other hand, if it is Yes in process S33, since the internal pressure has reached Pl, the switching valve 12a of the first line 12 is closed (process S35), and it returns to the measurement S2 of P above.

[0025] 2.4. When P < Pl When P < Pl, it proceeds by control S40 as shown in Fig. 6. This is the case where the internal pressure of the pressure vessel 11 is below the pressure lower limit specified value Pl. At this time, both the switching valve 12a of the first line 12 and the switching valve 13a of the second line 13 are opened (process S41). According to this, the internal pressure of the pressure vessel 11 is decreasing, and there is a pressure difference corresponding to the height of the liquid in the pressure vessel 11. Therefore, a part of the fluid vaporized in the vaporizer 16 branches at position G and gas flows toward the gas layer of the pressure vessel 11 as shown by the straight arrow A in Fig. 1, increasing the internal pressure of the pressure vessel 11. Note that another part of the fluid vaporized in the vaporizer 16 is supplied to the supply target 1. After that, P is measured again by the pressure gauge 15 (process S42), and it is determined by the control device 20 that P = Pu (process S43). If it is No in process S43, since the internal pressure of the pressure vessel 11 has not reached the pressure upper limit specified value Pu, the switching valves 12a and 13a maintain the state of process S41 (process S44), and it returns to process S42. On the other hand, if it is Yes in process S43, since the internal pressure P has reached Pu, the switching valve 12a of the first line 12 is closed (process S45), and it returns to the measurement S2 of P above.

[0026] 2. Effects etc. According to the present disclosure, if the internal pressure of the pressure vessel falls below the specified lower pressure limit, the internal pressure of the pressure vessel is increased by process S40, and if the internal pressure of the pressure vessel exceeds the specified upper pressure limit, the internal pressure of the pressure vessel is decreased by process S30, so that the internal pressure of the pressure vessel can be appropriately controlled and stably kept between the specified lower pressure limit and the specified upper pressure limit.

[0027] 3. Other forms In another embodiment, the gas supply system 10 may not include the switching valve 12a in the first line 12. This allows the effects of the gas supply system 10 to be achieved while reducing and simplifying the system components. In this other embodiment, control is performed as shown in control S101 in FIG. 7. The steps S2 for measuring P, S3 for valve control based on the value of P, and S4 for valve control, which constitute control S101, are the same as those described above. However, the valve control S4 performed here is performed by control S10 shown in FIG. 3 and control S110 shown in FIG. 8. The details are as follows.

[0028] 3.1.When P≧Ps If P≧Ps, the process proceeds according to control S10 shown in FIG.

[0029] 3.2.When Pl≦P≦Pu If Pl≦P≦Pu, the process proceeds according to control S110 as shown in Fig. 8. At this time, the switching valve 13a of the second line 13 is closed (step S111). As a result, the gaseous fluid flows from the pressure vessel 11 through the first line 13 and the gas is supplied to the supply target 1. If this continues, the internal pressure of the pressure vessel 11 decreases. Therefore, next, the internal pressure of the pressure vessel 11 is obtained by the pressure gauge 15 (process S112), and it is determined whether P < Pl (process S113). If this is No, since the pressure vessel 11 has not yet fallen below Pl, the valve state in process S111 is maintained (process S114), and the process returns to S112. On the other hand, if it is Yes in process S113, since P has fallen below Pl, the switching valve 13a of the second line 13 is changed to the open state (process 115). Thereby, as described in control S40, gas can be supplied to the supply target 1 while increasing the internal pressure of the pressure vessel 11. Continuing this, the internal pressure of the pressure vessel 11 rises. Therefore, next, the internal pressure of the pressure vessel 11 is obtained by the pressure gauge 15 (process S116), and it is determined whether P > Pu (process S117). If this is No, since the pressure vessel 11 has not yet reached Pu, the valve state in process S115 is maintained (process S118), and the process returns to S116. On the other hand, if it is Yes in process S117, since P exceeds Pu, the process returns to S111, the switching valve 13a of the second line 13 is changed to the closed state, and then the above is repeated.

[0030] 3.3. When Pu < P < Ps When Pu < P < Ps, it may start from process S111 of control S110 shown in FIG. 8.

[0031] 3.4. When P < Pl When P < Pl, it may start from process S115 of control S110 shown in FIG. 8.

Explanation of Signs

[0032] 10… Gas supply system, 11… Pressure vessel, 12… First line, 12a… Switching valve, 13… Second line, 13a… Switching valve, 14… Safety valve, 15… Pressure gauge, 16… Vaporizer, 20… Control device

Claims

1. A system for supplying gas to a supply target from a gas-liquid mixed fluid stored in a pressure vessel, comprising: a first line connected to the gas layer within the pressure vessel; a second line connected to the liquid layer in the pressure vessel, having a vaporizer therein, and joining the first line downstream of the vaporizer; a valve disposed in the second line between the pressure vessel and the vaporizer; a pressure gauge for measuring the pressure inside the pressure vessel; a control device; The control device receives pressure information from the pressure gauge, and when the internal pressure of the pressure vessel falls below a predetermined value, controls the valve to be in an open state so that a portion of the gas vaporized by the vaporizer of the second line is supplied from the first line to the pressure vessel, and the other portion is supplied to the supply target. Gas supply system.

2. A gas supply system as described in claim 1, wherein the control device receives pressure information from the pressure gauge and, when the internal pressure of the pressure vessel exceeds a predetermined value, controls the valve to be closed so that gas is supplied from the first line to the supply target.

3. 3. The gas supply system according to claim 1, wherein the first line is also provided with a valve, the opening and closing of which is controlled by the control device.

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