Gas concentration control device

Abstract

This invention provides a control method for situations where not only the supply amount of the mixed gas but also the concentration of the gas components in the mixed gas does not match the demand. [Solution] The system comprises a plurality of gas separation devices 1 to 3 that adjust the concentration of any gas component contained in the mixed gas and output the adjusted mixed gas, and a control device 15 that controls the concentration of the gas component and the flow rate of the mixed gas output from the gas separation devices 1 to 3 according to the demand of the gas consumer, and also detects the occurrence of an abnormality in the gas separation devices 1 to 3. When the control device 15 detects an abnormality in the gas separation devices 1 to 3, it controls the output of the gas separation devices that are not experiencing an abnormality, and uses the mixed gas output from the plurality of gas separation devices 1 to 3, including the gas separation device that experienced the abnormality, to adjust the concentration of the gas component and the flow rate of the mixed gas supplied to the gas consumer to meet the demand.

Description

[Technical Field]

[0001] This invention relates to a gas concentration control device. [Background technology]

[0002] In Europe and other regions, hydrogen is being injected into existing gas lines to decarbonize gas usage by gas consumers. Gas consumers can use either existing gases such as natural gas or hydrogen gas, or both. In gas concentration control systems used in such grids, equipment to adjust the concentration of the gas used, such as hydrogen concentration, according to the gas consumer's demand is essential. However, in gas concentration control systems, if some sudden malfunction occurs, such as a failure of the gas separation device that separates hydrogen from the mixed gas, or a malfunction of other equipment, there is a possibility that the flow rate of the product gas or the hydrogen concentration cannot be controlled according to demand. In other words, there is a concern that the state quantities (flow rate, concentration of gas components) of the mixed gas as the product gas cannot be maintained.

[0003] Regarding gas demand and supply, Patent Document 1 discloses a gas supply system equipped with an integrated supply and demand adjustment device that temporarily limits gas demand when gas supply capacity is temporarily insufficient to meet gas demand. Patent Document 1 describes planning the amount of gas to be stored and the gas pressure in the pipelines for storage, which will be manufactured during off-peak hours such as late at night and stored in holders and gas pipelines, and then released during peak hours such as evening when demand increases. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-203276 [Overview of the project] [Problems that the invention aims to solve]

[0005] As described above, the gas supply system described in Patent Document 1 discloses one effective control method for when the gas supply capacity is insufficient to meet the demand. However, in a mixed gas supply system in which hydrogen or the like is injected into an existing gas line, control methods are not explicitly stated for when not only the supply amount of the mixed gas, but also the concentration of any gas component in the mixed gas does not match the demand.

[0006] Given the above situation, there was a need for a configuration suitable for controlling the supply amount of mixed gas and the concentration of gas components in the mixed gas when some kind of sudden anomaly occurs and the state quantity of the mixed gas supplied to gas consumers does not match the demand. [Means for solving the problem]

[0007] To solve the above problems, a gas concentration control device according to one aspect of the present invention comprises a plurality of gas separation devices that adjust the concentration of any gas component contained in a mixed gas and output the adjusted mixed gas, and a control device that controls the concentration of the gas component of the mixed gas output from the gas separation devices and the flow rate of the mixed gas according to the demand of the gas consumer, and also detects the occurrence of an abnormality in a gas separation device. When the control device detects an abnormality in a gas separation device, it controls the output of the gas separation devices that are not abnormal, and uses the mixed gas output from the plurality of gas separation devices, including the gas separation device that has experienced an abnormality, to adjust the concentration of the gas component of the mixed gas supplied to the gas consumer and the flow rate of the mixed gas to meet the demand. [Effects of the Invention]

[0008] According to at least one aspect of the present invention, a configuration suitable for controlling the supply amount of mixed gas and the concentration of gas components in the mixed gas can be provided when some sudden abnormality occurs and the state quantity of the mixed gas supplied to the gas consumer does not match the demand. This configuration can minimize the impact on gas consumers due to sudden abnormalities, for example. Other issues, configurations, and effects not mentioned above will be clarified by the following description of embodiments for carrying out the invention. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram showing an example of the configuration of a gas concentration control device according to the first embodiment of the present invention. [Figure 2] This is a diagram showing another example of the configuration of a gas concentration control device according to the first embodiment of the present invention. [Figure 3] This is a diagram showing an example of the hardware configuration of a computer included in a gas concentration control device according to the first embodiment of the present invention. [Figure 4] This is a graph showing an example of a change in gas flow rate in a gas concentration control device according to the first embodiment of the present invention. [Figure 5] This is a graph showing an example of a change in hydrogen concentration in a gas concentration control device according to the first embodiment of the present invention. [Figure 6] This is a graph showing another example of a change in gas flow rate in a gas concentration control device according to the first embodiment of the present invention. [Figure 7] This is a graph showing another example of a change in hydrogen concentration in a gas concentration control device according to the first embodiment of the present invention. [Figure 8] This is a flowchart showing the processing flow of a gas concentration control device according to the first embodiment of the present invention. [Figure 9] This is a flowchart showing an example of the procedure for evaluating whether to continue operation according to the first embodiment of the present invention. [Figure 10] This is a diagram showing an example of a display screen of a gas concentration control device according to the second embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, examples of embodiments for carrying out the present invention (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. In this specification and the accompanying drawings, common components or similar components are denoted by the same reference numerals, and redundant descriptions are omitted. The number of each component may be singular or plural unless otherwise specified.

[0011] <First Embodiment> First, the configuration of the gas concentration control device according to the first embodiment of the present invention will be described with reference to Figure 1. The gas concentration control device according to this embodiment is a device that manages and controls the supply status of existing gas and hydrogen when hydrogen produced by, for example, electrolysis of water using renewable energy or reforming of natural gas is mixed with existing gas and supplied to hydrogen users via pipeline.

[0012] [Configuration of the gas concentration control device] Figure 1 shows an example of the configuration of a gas concentration control device according to the first embodiment of the present invention. The gas concentration control device 100 shown in Figure 1 is mainly composed of gas separators 1-3, a buffer tank 4, compressors 5-6, control valves 7-11, sensors 12-14, a control unit 15, a display device 16, and an input device 17. Generally, the gas concentration control device 100 is installed near the equipment 200 that uses the product gas 26 of a gas consumer, but it may also be installed in a location away from the equipment 200. Note that the configuration of the gas concentration control device 100 is just an example, and the number of gas separators, buffer tanks, control valves, and sensors can be changed. For example, there may be two gas separators or four or more. Also, some of these may be installed outside the gas concentration control device 100.

[0013] Gas separators 1-3 are devices that extract certain gas components from a supply gas 21 (an example of a mixed gas) which contains multiple different gas components. Examples of these different gas components include natural gas and hydrogen gas. In the gas pipeline through which the supply gas 21 passes to gas separators 1-3, control valves 7-9 are installed upstream of gas separators 1-3. Gas separators 1-3 extract a desired gas component from the supply gas 21, adjust the concentration of that gas component to a target value, and output regulated gases 23-25. When gas separators 1-3 are functioning correctly, the concentration of the gas component (e.g., hydrogen concentration) in the regulated gases 23-25 ​​output from each gas separator 1-3 is within a certain acceptable margin of error.

[0014] The gas concentration control device 100 then supplies a mixed gas, formed by mixing all the adjustment gases 23-25 ​​via the adjustment valve 10, as product gas 26 to the gas consumer's equipment 200. While various gas separation methods exist for gas separation devices, such as membrane separation and pressure fluctuation separation, the present invention does not limit these gas separation methods.

[0015] The buffer tank 4 is a tank that stores at least a portion of the product gas 26. The buffer tank 4 stores the product gas 26 that has been pressurized through the compressor 5. By storing the pressurized product gas 26, when the flow rate of product gas 26 requested by the gas consumer temporarily exceeds the total flow rate of all the adjustment gases 23-25, the buffer tank 4 supplies the insufficient amount of product gas 26 via the adjustment valve 11. The buffer tank 4 is not mandatory, but by providing it, as described above, when the flow rate requested by the gas consumer exceeds the maximum flow rate that can be output from the gas separation devices 1-3, the product gas 26 in the buffer tank 4 can be used to replenish the shortage.

[0016] In the configuration shown in Figure 1, the buffer tank 4 is installed in parallel with the gas conduit that supplies product gas 26, a mixture of uncompressed adjustment gases 23-25, to the gas consumer's equipment 200. The buffer tank 4 can be equipped with sensors to measure one or more of the following: the remaining amount of stored gas, pressure, temperature, composition, concentration, and the flow rate of the gas being input or output. The measured values ​​from these sensors may be transmitted to the control unit 15. Alternatively, the buffer tank 4 may be configured on the same gas conduit as the gas conduit through which the product gas 26 passes, as shown in the configuration in Figure 2.

[0017] [Primary configuration of gas concentration control device] Figure 2 shows another example of the configuration of the gas concentration control device 100A according to the first embodiment of the present invention. In the configuration shown in Figure 1, there is a gas conduit with a control valve 10 and a gas conduit with a buffer tank 4 between the gas separation devices 1 to 3 and the gas consumer's equipment 200. However, in the configuration of the gas concentration control device 100A shown in Figure 2, only the gas conduit with the buffer tank 4 is provided.

[0018] As shown in Figure 2, when the buffer tank 4 is placed on the same gas conduit as the gas conduit through which the product gas 26 passes, the control valve 10 and a portion of the gas conduit through which the mixed gas passes (bypass portion) become unnecessary compared to the configuration shown in Figure 1. This has the advantage of simplifying the configuration of the gas concentration control device 100A. Furthermore, since the compressor 5 can be operated continuously while the product gas 26 is supplied to the gas consumer's equipment 200, there is also the advantage of further simplifying the configuration of the system (including the control program algorithm) for controlling the operation of the compressor 5. On the other hand, when the gas consumer's required concentration of each gas component of the product gas 26 fluctuates, there is a disadvantage that it may not be possible to supply gas at the required concentration until the product gas 26 in the buffer tank 4 is depleted.

[0019] On the other hand, the gas concentration control device 100 shown in Figure 1 can mix the product gas 26 in the buffer tank 4 with the adjustment gases 23-25 ​​output from the gas separation devices 1-3, even when the required concentrations of each gas component of the product gas 26 by the gas consumer fluctuate. As a result, the gas concentration control device 100 has the advantage of being able to perform replacement control of the product gas 26 in the buffer tank 4 while meeting the required concentration.

[0020] Returning to the explanation of Figure 1, compressor 6 is a compressor that pressurizes the residual gas 22, which is the excess gas from the gas separation devices 1 to 3. The residual gas 22 is the difference between the supply gas 21 and the adjustment gases 23 to 25. The residual gas 22 is processed by being returned to the pipeline that supplied the supply gas 21, but the present invention does not limit the method of processing the residual gas 22. Furthermore, if pressurization of the gas by compressor 6 is not necessary in the processing of the residual gas 22, compressor 6 may be omitted.

[0021] The control valves 7-9 are valves that adjust the flow rate of the supply gas 21 flowing into each of the gas separation devices 1-3. The valve opening of the control valves 7-9 is controlled by the control unit 15. In Figure 1, the same number of control valves 7-9 as there are gas separation devices 1-3 are configured, but a control valve that controls the gas flow rate flowing into multiple gas separation devices together may also be configured. The present invention is not limited to combinations of gas separation devices and control valves.

[0022] The control valve 10 is a valve that controls the flow rate of the product gas 26. The valve opening of the control valve 10 is determined by the balance between the amount of gas demanded by the gas consumer and the total flow rate of the regulating gases 23-25. In Figure 1, the arrows are omitted for structural reasons, but the control unit 15 can be used to control the valve opening of the control valve 10. Alternatively, the valve opening of the control valve 10 may be manually operated by an administrator or remotely controlled by a monitoring center of the gas supply company.

[0023] The control valve 11 is a valve that controls the flow rate of the product gas 26 output from the buffer tank 4. As mentioned above, in the configuration shown in Figure 1, when the gas consumer's requested flow rate of product gas 26 temporarily exceeds the total output of all the regulating gases 23-25, the control valve 11 is opened to supply the insufficient amount of product gas 26 from the buffer tank 4. The valve opening degree of the control valve 11 for supplying the insufficient amount of product gas 26 is controlled by the control unit 15. In the configuration shown in Figure 2, the control valve 11 also performs the role of the control valve 10 shown in Figure 1.

[0024] Sensors 12-14 are devices that measure one or more of the following: the composition of the regulated gases 23-25 ​​output from the gas separation devices 1-3, the concentration of each gas component, the flow rate, pressure, and temperature. The measured values ​​from sensors 12-14 are transmitted to the control unit 15. The control unit 15 can use the measured values ​​from sensors 12-14 to calculate the valve opening and the operating amount of the equipment.

[0025] The control unit 15 (an example of a control device) is a device that controls and monitors the operating parameters of the equipment (gas separators, valves, and other devices) provided by the gas concentration control devices 100 and 100A, including the valve openings of the regulating valves 7 to 11. The control unit 15 controls the flow rate of the mixed gas (regulating gases 23 to 25) output from the gas separators 1 to 3 and the concentration of the gas components in the mixed gas according to the demand of the gas consumer. The control unit 15 also detects abnormalities in the gas separators 1 to 3. Here, abnormality detection may be performed for each gas pipeline system. For example, if an abnormality occurs in the regulating valve 7 or sensor 12, it will interfere with the control of the regulating gas 23 output from the gas separator 1. Therefore, if an abnormality occurs in the regulating valve 7 or sensor 12, it may be included in an abnormality of the gas separator 1 in a broad sense.

[0026] Although omitted in Figures 1 and 2 for structural reasons, the measured values ​​from sensors 12 to 14 may also be used to calculate the valve openings and other equipment operating parameters within gas separation devices 1 to 3. For example, such equipment includes the heaters of the gas heat exchangers in gas concentration control devices 100 and 100A. An abnormality in the gas separation device due to the malfunction of equipment is sometimes referred to as an "equipment malfunction."

[0027] Similarly, although omitted for structural reasons, measurement values ​​other than those from sensors 12-14 may be used to calculate the valve opening and the amount of equipment operation. Methods such as PID control, model predictive control, and AI (Artificial Intelligence) control can be applied to the calculation method for the valve opening and the amount of equipment operation in the control unit 15. However, the calculation method for the valve opening and the amount of equipment operation is not limited in this invention.

[0028] If the buffer tank 4 is not in use or there is no remaining mixed gas (product gas 26) in the buffer tank 4, the control unit 15 performs the following control. If the control unit 15 detects an abnormality in any of the gas separation devices 1 to 3, it controls the output of the gas separation device that is not abnormal, and uses the mixed gas (adjusted gases 23 to 25) output by the multiple gas separation devices 1 to 3, including the gas separation device that has abnormality, to adjust the concentration of the gas components (e.g., hydrogen concentration) and the flow rate of the mixed gas supplied to the gas consumer to meet the demand. With this configuration, the gas concentration control devices 100 and 100A of this embodiment can supply mixed gas (product gas 26) that meets the demands of gas consumers using the mixed gas output from a gas separation device that is not experiencing any abnormalities, without using the mixed gas in the buffer tank 4. Therefore, the impact on gas consumers due to sudden abnormalities can be minimized.

[0029] Furthermore, if the control unit 15 detects an abnormality in any of the gas separation devices 1 to 3, it controls the output of the buffer tank 4 and the gas separation devices that are not experiencing abnormalities, thereby adjusting the concentration of gas components (e.g., hydrogen concentration) and the flow rate of the mixed gas (product gas 26) supplied to the gas consumer to meet the demand. With this configuration, the gas concentration control devices 100 and 100A of this embodiment can supply mixed gas (product gas 26) that meets the demands of gas consumers using the mixed gas in the buffer tank 4 and the mixed gas output by the gas separation device that is not experiencing any abnormalities. Therefore, the impact on gas consumers due to sudden abnormalities can be minimized. At the very least, any shortage of product gas 26 supplied to gas consumers can be quickly replenished using the product gas 26 stored in the buffer tank 4, within the limits of its remaining amount.

[0030] The display device 16 is used to present information to the administrator of the gas concentration control devices 100 and 100A. The display device 16 displays a GUI (Graphical User Interface) screen and the results of calculations performed by the CPU 31, as shown in Figure 3 below. For example, the display device 16 is a liquid crystal display or the display unit of a terminal such as a smartphone or tablet.

[0031] The input device 17 is used by the administrator of the gas concentration control devices 100 and 100A to input management information and commands to the gas concentration control devices 100 and 100A. The input device 17 generates an input signal corresponding to the administrator's operation and outputs it to the CPU 31. For example, the input device 17 may be a keyboard, mouse, joystick, or touch panel.

[0032] [Hardware configuration of the gas concentration control device] Figure 3 shows an example of the computer hardware configuration of the gas concentration control devices 100 and 100A according to the first embodiment. The computer 30 shown in Figure 3 is an example of hardware used as a computer. The gas concentration control devices 100 and 100A achieve gas concentration control by the control unit 15 when the computer 30 executes a program.

[0033] Computer 30 includes a CPU (Central Processing Unit) 31, ROM (Read Only Memory) 32, RAM (Random Access Memory) 33, non-volatile storage 36, and a communication interface 37 connected to a system bus. A display device 16 and an input device 17 are connected to computer 30.

[0034] The CPU 31 reads the program code for the software that implements each function according to this embodiment from the ROM 32, loads it into the RAM 33, and executes it. Variables and parameters that occur during the calculation process of the CPU 31 are temporarily written to the RAM 33, and these variables and parameters are read out by the CPU 31 as appropriate. The functions of the gas concentration control devices 100 and 100A (control unit 15) are realized when the CPU 31 executes the program code read from the ROM 32. However, other processors such as an MPU (Micro Processing Unit) may be used instead of the CPU 31.

[0035] Non-volatile storage 36 is an example of a recording medium that can store data used by a program or data obtained by executing a program. Furthermore, the operating system (OS) and programs executed by the CPU 31 may be recorded on the non-volatile storage 36. Examples of non-volatile storage 36 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), optical discs utilizing light (and magnetism), or semiconductor memory cards.

[0036] A communication device such as a NIC (Network Interface Card) can be used for the communication interface 37. The communication interface 37 can send and receive various types of data to and from external devices via a communication network such as a LAN, a dedicated line, etc. Communication between the control unit 15 and the equipment in the gas concentration control devices 100 and 100A may also be realized using the communication interface 37.

[0037] Furthermore, the gas consumer's equipment 200 can employ the same hardware configuration as the computer 30 shown in Figure 3. Similarly, the terminals used by administrators of the gas concentration control devices 100 and 100A, and administrators of the gas consumer's equipment 200, can also utilize the same hardware configuration as the computer 30 shown in Figure 3.

[0038] In the gas concentration control devices 100 and 100A described above, the control unit 15, even after detecting an abnormality in the gas separation device, determines whether the gas customer's equipment 200 can continue operating based on whether the concentration of gas components (e.g., hydrogen concentration) and the flow rate of the mixed gas (product gas 26) supplied to the gas customer can meet the gas customer's demand. Then, according to the determination result of whether operation can continue, the control unit 15 stops the gas separation device or the gas customer's equipment 200 where the abnormality occurred, and controls the output of the buffer tank 4 and the gas separation device where no abnormality has occurred.

[0039] Thus, in this embodiment, by stopping the gas separation device or the gas consumer's equipment 200 where an abnormality has occurred, according to the determination result of whether or not operation can be continued, the supply and stopping of product gas can be safely controlled. In other words, safe operation of the gas concentration control device 100 and the gas consumer's equipment 200 is possible.

[0040] The following will specifically explain, with reference to two gas concentration control examples, how to control the output of buffer tank 4 and gas separation devices where no abnormalities have occurred, according to the result of the determination of whether operation can be continued.

[0041] [Gas concentration control (1)] Next, referring to Figures 4 and 5, an example of a control method will be described for when some abnormality occurs in the gas separation device 1 of the gas concentration control device 100, and it becomes impossible to control the gas concentration and gas flow rate of the regulated gas 23 output from the gas separation device 1.

[0042] In this example, the supply gas 21 is a mixed gas of natural gas and hydrogen, and the gas consumer's equipment 200 supplies 9 Nm³ of the mixed gas with a hydrogen concentration of 20%. 3 It is assumed that a constant supply at a flow rate of / h is required. Figure 4 illustrates the flow rate control of the mixed gas, and Figure 5 illustrates the hydrogen concentration control. In this example, the hydrogen gas concentration is adjusted, but a configuration that adjusts the natural gas concentration may also be used.

[0043] (Changes in gas flow rate) Figure 4 is a graph showing an example of the change in gas flow rate in the gas concentration control device 100. In the example in Figure 4, the demand (solid line) is the requested flow rate of product gas 26 from the gas consumer, and the production flow rate (dashed line) is the total flow rate of all adjustment gases 23-25. Gas flow rate A (short dashed line) is the flow rate of adjustment gas 23 from gas separator 1, and gas flow rate B (long dashed line) is the flow rate of adjustment gases 24 and 25 from gas separator 2 and gas separator 3, respectively. Furthermore, the tank output (double dashed line) is the flow rate of product gas 26 output from buffer tank 4.

[0044] In this example, a malfunction in gas separation device 1 (time t1) caused the gas flow rate A to be 3 Nm³. 3 / h to 1Nm 3 The production flow rate decreases to 9 Nm³ / h over time, and consequently, the production flow rate also decreases to 9 Nm³ / h. 3 / h to 7Nm 3 The flow rate is decreasing to / h. In response, the control unit 15 calculates the rate of decrease of gas flow rate A or a predicted value for each unit of time. Based on the calculation results, the control unit 15 adjusts the valve opening of the control valve 11 to set the output of the buffer tank 4 to 0 Nm 3 / h to 2Nm 3 By increasing the setting to / h, the tank output and production flow rate are controlled to match the demand.

[0045] Furthermore, after an abnormality occurs, the control unit 15 determines whether or not to continue operating the gas customer's equipment 200. To determine whether or not to continue operation, one or more of the following can be used: the maximum production flow rate of the product gas 26 that meets the gas composition and concentration requirements of the gas customer's equipment 200 after the abnormality occurs, the demand amount, or the remaining amount of product gas 26 in the buffer tank 4. Whether or not to continue operating the gas customer's equipment 200 is determined by whether the state quantity of the product gas 26 can meet the gas customer's demand. In the examples of Figures 4 and 5, the control unit 15 determines to continue operating the gas customer's equipment 200 and the gas concentration control device 100.

[0046] In FIG. 4, after determining to continue operation, the control unit 15 controls to increase the production flow rate by increasing the respective flow rates of the adjustment gases 24 and 25 of the normal gas separation device 2 and the gas separation device 3 (time t2). In FIG. 4, during the same period, the gas flow rate B (the respective flow rates of the adjustment gases 24 and 25) increases from 3 Nm 3 / h to 4 Nm 3 / h, and the production flow rate increases from 7 Nm 3 / h to 9 Nm 3 / h. Here, since the production flow rate satisfies the demand, the control unit 15 adjusts the valve opening degree of the adjustment valve 11 to set the tank output to 0 Nm 3 / h, thereby stopping the buffer tank 4 (time t3).

[0047] After stopping the buffer tank 4, the control unit 15 stops the gas separation device 1 in which an abnormality has occurred by adjusting the valve opening degree of the adjustment valve 7 (time t4). In FIG. 4, the stop of the gas separation device in which an abnormality has occurred is described as "abnormal device stop". Due to the stop of the gas separation device 1, the gas flow rate A (the flow rate of the adjustment gas 23) decreases to 0 Nm 3 / h. Therefore, at the same time, the control unit 15 increases the gas flow rate B (the respective flow rates of the adjustment gases 24 and 25) from 4 Nm 3 / h to 4.5 Nm 3 / h so that the production flow rate satisfies the demand of 9 Nm 3 / h. The control unit 15 continues to operate the gas concentration control device 100 using the gas separation devices 2 and 3.

[0048] Note that there is no limitation on the order of stopping the gas separation device 1 and the output stop of the buffer tank 4. Depending on the capacity of the buffer tank 4, the gas separation device 1 may be stopped before the output stop of the buffer tank 4.

[0049] (Change in hydrogen concentration) FIG. 5 is a graph showing an example of the change in hydrogen concentration in the gas concentration control device 100. Referring to FIG. 5, the hydrogen concentration control in the same assumption as in FIG. 4 will be described. In the example in Figure 5, the demand concentration (solid line) is the concentration of hydrogen gas (an example of a gas component) in the product gas 26 requested by the gas consumer. Concentration A (short dashed line) is the hydrogen concentration of the adjustment gas 23 in gas separator 1, and concentration B (long dashed line) is the hydrogen concentration of the adjustment gases 24 and 25 in gas separator 2 and gas separator 3, respectively.

[0050] In this example, an abnormality in gas separator 1 (time t1) causes a decrease in the flow rate of regulating gas 23 (gas flow rate A), and simultaneously, the hydrogen concentration of regulating gas 23 (concentration A) decreases from 20% to 8% (time t2). In response, the control unit 15 increases the valve openings of regulating valves 8 and 9, and the valve openings of the valves through which hydrogen gas extracted from the mixed gas flows inside gas separators 2 and 3, thereby increasing the hydrogen concentration of concentration B from 20% to 22%. Through this adjustment, the hydrogen concentration of the product gas 26 supplied to the gas consumer is maintained at the demand concentration of 20%.

[0051] Subsequently, as the output of buffer tank 4 approaches shutdown (time t3), the gas flow rate B increases to 3 Nm 3 / h to 4Nm 3 The rate increases to / h. In response, the control unit 15 reduces the hydrogen concentration of concentration B from 22% to 21.5% in order to maintain the hydrogen concentration of the product gas 26 at 20%.

[0052] Furthermore, after the output of buffer tank 4 stops, as the malfunctioning gas separation device 1 approaches shutdown (time t4), the gas flow rate A increases to 1 Nm 3 / h to 0Nm 3 The gas flow rate B decreases to 4 Nm³ / h. 3 / h to 4.5Nm 3 The rate increases to / h. In response, the control unit 15 reduces the hydrogen concentration of concentration B from 21.5% to 20% in order to maintain the hydrogen concentration of the product gas 26 at 20%.

[0053] In this gas concentration control, if the concentration of the gas component (e.g., hydrogen concentration) of the mixed gas (product gas 26) requested by the gas consumer differs from the concentration of the gas component of the mixed gas output from the gas separation device where the malfunction occurred, the control unit 15 mixes the mixed gas (adjustment gas 24, 25) output from the gas separation device that is not malfunctioning, and the mixed gas (product gas 26) in the buffer tank 4, or both, with the mixed gas (adjustment gas 23) output from the gas separation device where the malfunction occurred. This makes it possible to control the system to reduce the error between the concentration of gas components in the mixed gas supplied to the gas consumer and the concentration of gas components in the mixed gas as requested by the gas consumer after an abnormality occurs.

[0054] Furthermore, in this gas concentration control, if the determination result of whether operation can be continued is that the gas consumer's equipment 200 can continue to operate, the control unit 15 stops the gas separation device where the malfunction occurred and supplies a mixed gas (product gas 26) that meets the gas consumer's demand using the mixed gas output from the buffer tank 4 and the gas separation device where no malfunction occurred. With this configuration, if the gas flow rate and hydrogen concentration of any gas separator become uncontrollable due to some abnormality, the malfunctioning gas separator is stopped, and the operation of the gas consumer's equipment 200 continues using the mixed gas output from the buffer tank 4 and the gas separators that are not malfunctioning. As a result, this embodiment can quickly restore the state variables (flow rate, gas component concentration) of the product gas 26 to their state before the abnormality occurred, minimizing the impact on the gas consumer.

[0055] As described above, the flow rate control of the mixed gas shown in Figure 4 and the hydrogen concentration control shown in Figure 5 enable a control method that, in the event that the gas flow rate and hydrogen concentration of the adjustment gas 23 become uncontrollable due to some abnormality, allows the gas separator 1 to be shut down while continuing the operation of the gas consumer's equipment 200 by satisfying the demand for the product gas 26 and the demand concentration of the target gas component. In this example, the concentration of hydrogen gas is adjusted, but a configuration that adjusts the concentration of natural gas may also be used.

[0056] [Gas concentration control (2)] Next, referring to Figures 6 and 7, an example of a control method for shutting down the gas consumer's equipment 200 and the gas concentration control device 100 when, due to some abnormality in the gas separation device 1 of the gas concentration control device 100, the gas concentration and gas flow rate of the regulated gas 23 become uncontrollable, and the demand for the product gas 26 can no longer be met.

[0057] In this example, the supply gas 21 is a mixed gas of natural gas and hydrogen, and the gas consumer's equipment 200 supplies 9 Nm³ of the mixed gas with a hydrogen concentration of 20%. 3 It is assumed that a constant supply at a flow rate of / h is required. Furthermore, in operation where the gas consumer's equipment 200 and gas concentration control device 100 are shut down, the hydrogen concentration of the mixed gas is maintained at 20%, while the gas flow rate is set to 9 Nm³. 3 From / h, time elapsed to 0Nm 3 It is assumed that the flow rate will decrease to / h. Here, the maximum flow rate of the regulated gas that can be output from each gas separation device 1 to 3 is 4 Nm³. 3 Let's assume a flow rate of / h. Figure 6 illustrates the flow rate control of the mixed gas, and Figure 7 illustrates the hydrogen concentration control. In this example, the hydrogen gas concentration is adjusted, but a configuration to adjust the natural gas concentration may also be used.

[0058] (Changes in gas flow rate) Figure 6 is a graph showing another example of gas flow rate changes in the gas concentration control device 100. In the example in Figure 6, the meanings of the lines representing demand (solid line), production flow rate (dotted line), gas flow rate A (short dashed line), gas flow rate B (long dashed line), and tank output (double dashed line) are the same as in the example in Figure 4.

[0059] In this example, a malfunction occurred in gas separation device 1 (time t11), causing the gas flow rate A to be 3 Nm³. 3 / h to 0Nm 3 The gas flow rate B decreases over time to / h. In response, the control unit 15 controls the gas flow rate B to 3Nm 3 / h to 4Nm 3 The flow rate of the product gas 26 output from the buffer tank 4 is increased to 0 Nm³ / h, and the flow rate of the product gas 26 output from the buffer tank 4 is also increased to 0 Nm³ / h. 3 / h to 1Nm 3 By increasing the rate to / h, the tank output and production flow rate are controlled to match the demand.

[0060] As mentioned above, after an abnormality occurs, the control unit 15 determines whether or not to continue operating the gas consumer's equipment 200. In the example in Figures 6 and 7, the flow rate of the regulating gas 23 (gas flow rate A) is 0 Nm. 3 At time t12, the flow rates of regulating gas 24 and regulating gas 25 (gas flow rate B) are set to the maximum of 4 Nm / s. 3 Even if we assume / h, the gas consumer's equipment 200 requires 9Nm 3 The flow rate of / h cannot be met. To meet the gas consumer's requirements, the output of product gas 26 from buffer tank 4 is essential. Therefore, the gas concentration control device 100 can only continue operation using the remaining amount of product gas 26 stored in buffer tank 4. Thus, in the examples of Figures 6 and 7, the control unit 15 determines to stop the operation of the gas consumer's equipment 200 and the gas concentration control device 100.

[0061] In Figure 6, after determining that operation should be stopped, the control unit 15 transmits the operation stop determination result or a demand stop request signal to the gas consumer's equipment 200. Upon receiving the operation stop determination result or the demand stop request signal, the gas consumer's equipment 200 begins operation toward stopping the equipment 200 (hereinafter referred to as "stop operation"), and consequently begins to decrease the amount of demand. The control unit 15 receives information on the changed amount of demand from the gas consumer's equipment 200 and, in accordance with the changed amount of demand, prioritizes reducing the output of the buffer tank 4 to make the flow rate of the product gas 26 follow the demand.

[0062] Subsequently, the control unit 15 determines that the output of the buffer tank 4 is 0 Nm 3 When it reaches / h (time t13), the gas flow rate B is reduced to make the flow rate of product gas 26 follow the demand. Then, the control unit 15 checks when the demand and gas flow rate B (output of gas separators 2 and 3) are 0 Nm 3 When the value reaches / h, the gas concentration control device 100 is completely shut down.

[0063] In the example above, we showed a case where the gas consumer's equipment 200 was requested to stop demand, but it is also conceivable that the gas consumer be asked to reduce the demand requested by equipment 200. For example, if the flow rate of product gas 26 requested by the gas consumer is 9 Nm³ 3 / h to 7Nm 3 By reducing the concentration to / h, the gas concentration control devices 100 and 100A can continue operating using the regulating gas 24 and regulating gas 25 without shutting down the gas consumer's equipment 200.

[0064] (Changes in hydrogen concentration) Figure 7 is a graph showing another example of the change in hydrogen concentration in the gas concentration control device 100. Referring to Figure 7, hydrogen concentration control under a similar assumption to Figure 6 will be explained. In the example in Figure 7, the meanings of the lines representing demand concentration (solid line), concentration A (short dashed line), and concentration B (long dashed line) are the same as in the example in Figure 5.

[0065] In this example, an abnormality occurs in the gas separation device 1 (time t11), causing the flow rate of the regulating gas 23 (gas flow rate A) to decrease, while the hydrogen concentration of the regulating gas 23 (concentration A) increases from 20% to 30% over time. In response, the control unit 15, based on concentration A, gas flow rate A, and gas flow rate B, reduces the hydrogen concentration of concentration B (hydrogen concentration of regulating gases 24 and 25) from 20% to approximately 18% so that the hydrogen concentration of the product gas 26 becomes the demand concentration of 20%.

[0066] Subsequently, the control unit 15 determines that the gas flow rate A is 0 Nm 3 As time t12 approaches, the hydrogen concentration of concentration B is gradually returned to 20%, maintaining the hydrogen concentration of product gas 26 at 20%. Strictly speaking, in addition to these, the gas flow rate and hydrogen concentration of product gas 26 supplied from buffer tank 4 are also taken into consideration. The same can be said for the graph examples shown in Figures 4 and 5.

[0067] Gas flow rate A is 0 Nm 3 After the output of buffer tank 4 stopped (time t13) at / h, the production flow rate became 0 Nm as the gas flow rate B decreased.3 It decreases towards / h. During this time, the control unit 15 maintains the hydrogen concentration of concentration B at 20% and supplies product gas 26 to meet the demand concentration.

[0068] In this gas concentration control, if the determination result for whether operation can be continued indicates that operation of the gas customer's equipment 200 cannot be continued, the control unit 15 notifies the gas customer's equipment 200 of the determination result. Then, until the gas customer's equipment 200 is shut down, the control unit 15 controls the output of the buffer tank 4 and the gas separation device that is not malfunctioning to reduce the flow rate of the mixed gas (product gas 26) to zero while satisfying the concentration of gas components of the mixed gas (product gas 26) required by the gas customer.

[0069] According to this embodiment with such a configuration, when the gas flow rate and hydrogen concentration of any gas separation device become uncontrollable due to some abnormality, it becomes possible to control the gas consumer's equipment 200 and gas concentration control device 100 to shut them down while satisfying the demand for product gas 26 and the demand for concentration.

[0070] Furthermore, according to this embodiment, the gas consumer's equipment 200 and gas concentration control device 100 are shut down while meeting the demand for product gas 26 (particularly the demand concentration). This ensures the safety of the equipment 200 and gas concentration control device 100 while minimizing the impact on the gas consumer.

[0071] [Processing by the gas concentration control device] Next, the processing of the gas concentration control device according to the first embodiment of the present invention will be described with reference to Figure 8. Figure 8 is a flowchart showing the processing flow of the gas concentration control device 100. The example in Figure 8 is an example of the processing algorithm by the control unit 15. The same applies to the processing of the gas concentration control device 100A. This processing will be explained in conjunction with the examples in Figures 4 and 5.

[0072] First, in processing step S1, the control unit 15 sets the control target values ​​for each piece of equipment in the gas concentration control device 100, including the control valves 7-11. For example, in the example in Figure 4, the hydrogen concentration of the product gas requested by the gas consumer's equipment 200 is 20%, and the gas flow rate is 9 Nm³. 3 Since it is / h, the target values ​​for the adjustment gases 23-25 ​​of each gas separation unit 1-3 are also 20% hydrogen concentration and 9 Nm³ gas flow rate. 3 It is set to / h.

[0073] However, if it is determined in the evaluation of whether operation can be continued in processing step S5 described later that an abnormality has occurred in some of the gas separators 1 to 3, the control target values ​​of each gas separator 1 to 3 are adjusted so that the average value (average concentration) and total flow rate of each gas component of all conditioned gases 23 to 25 meet the target value of the product gas 26. Here, the conditioned gases of all gas separators 1 to 3 are targeted regardless of whether an abnormality has occurred. However, the adjustment of the control target values ​​is limited to gas separators where no abnormality has occurred. In addition, if there are updates to the target values ​​such as the demand amount and required concentration of the product gas 26 requested by the gas consumer's equipment 200, the control unit 15 may receive the updated target values ​​from the gas consumer's equipment 200 during this processing step.

[0074] Next, in processing step S2, the control unit 15 calculates the operating amounts for valves and other equipment of each gas separation device 1 to 3 based on the control target values ​​for the gas concentration of each gas separation device 1 to 3. Then, the control unit 15 controls the concentration of the gas components of the regulated gases 23 to 25 output from each gas separation device 1 to 3 based on the operating amounts for valves and other equipment of each gas separation device 1 to 3. The control target values ​​for the gas concentration are the values ​​determined in processing step S1.

[0075] Next, in processing step S3, the control unit 15 calculates the operating amounts for valves and other equipment of each gas separation device 1 to 3 based on the target control values ​​for the gas flow rate of each gas separation device 1 to 3. Then, the control unit 15 controls the flow rate of the adjustment gases 23 to 25 output from each gas separation device 1 to 3 based on the operating amounts for valves and other equipment of each gas separation device 1 to 3. The target control value for the gas flow rate is the value determined in processing step S1. In this invention, there are no restrictions on the order of calculations in processing step S2 and processing step S3, and the calculation order of the operating amounts for controlling the flow rate and concentration of the adjustment gas may be changed as needed.

[0076] Next, in processing step S4, the control unit 15 calculates the flow rate of the product gas 26 to be input and output to the buffer tank 4, and further calculates the operating amounts for the compressor 5 and the control valve 11 based on the calculated flow rate of the product gas 26. Then, the control unit 15 controls the input and output of the product gas 26 to the buffer tank 4 based on the operating amounts for the compressor 5 and the control valve 11.

[0077] One configuration for outputting product gas 26 from buffer tank 4 is when the total value of all adjustment gases 23-25 ​​is less than the demand for product gas 26. Conversely, one configuration for storing product gas 26 in buffer tank 4 is when the total value of all adjustment gases 23-25 ​​exceeds the demand for product gas 26. There are no restrictions on the order of calculations in processing steps S2-S4, and the tank input / output control in processing step S4 may be performed before processing steps S2 and S3.

[0078] Next, in processing step S5, the control unit 15 evaluates whether the operation of the gas consumer's equipment 200 can be continued. In evaluating whether operation can be continued, the control unit 15 determines whether, even after the abnormality occurs, the flow rate of the product gas 26 supplied to the gas consumer and the concentration of each gas component can meet the gas consumer's demand or its predicted value. Details of the evaluation method for whether operation can be continued will be described later with reference to Figure 9.

[0079] Next, in processing step S6, it is determined whether to continue controlling the gas concentration control device 100. For example, if the gas concentration control device 100 is stopped due to the shutdown of the gas consumer's equipment 200, and control of the gas concentration control device 100 is no longer needed, the control unit 15 determines to stop control (NO determination) and terminates the algorithm. Conversely, if control is to be continued (YES determination), the process proceeds to processing step S1, and processing steps S1 to S6 are executed again.

[0080] [Evaluation of whether operation can continue] Next, the evaluation of whether or not operation can be continued in processing step S5 in Figure 8 will be explained with reference to Figure 9. Figure 9 is a flowchart showing an example of the procedure for evaluating whether operation can be continued in processing step S5 of Figure 8.

[0081] First, in processing step S11 shown in Figure 9, the control unit 15 determines if there is an abnormality in the equipment (such as a gas separation device) of the gas concentration control device 100. For example, if the error between the target value set in processing step S1 and the current value of the average concentration or total flow rate of each gas component of the adjustment gases 23 to 25 does not improve for a period of time set in advance, an abnormality is determined. However, the means for determining an abnormality in the equipment are not limited in this invention. For example, examples of cases in which an abnormality is determined include when the error is larger than a predetermined value and does not improve even after a period of time set in advance, or when the error is so large that it is necessary to immediately stop the gas concentration control device 100.

[0082] Next, in processing step S12, the process branches based on the determination result from processing step S11. If it is determined that an abnormality has occurred in the equipment of the gas concentration control device 100 (YES determination), the process proceeds to processing step S13; if it is determined that no abnormality has occurred (NO determination), the process proceeds to processing step S16.

[0083] In processing step S13, the control unit 15 evaluates the remaining amount of product gas 26 in the buffer tank 4 based on the measurement values ​​of a sensor (not shown). Note that if the remaining amount of product gas 26 in the buffer tank 4 is not used in determining whether or not to continue operating the equipment where the malfunction has occurred (described later), this processing step may be omitted and the process may proceed to the next processing step.

[0084] Next, in processing step S14, the control unit 15 acquires or predicts fluctuation information for both demand and supplied gas 21, including future data for the gas consumer's equipment 200, i.e., for a predetermined period ahead. Demand fluctuations may be acquired through communication with the gas consumer's equipment 200 or through the equipment 200's operating plan. Similarly, supply gas fluctuation information may be acquired through communication with external equipment such as a hydrogen production plant or a gas concentration control device 100.

[0085] Alternatively, the fluctuations in demand and supply gas 21 may be predicted using simulators or models. For example, estimation methods using models that estimate fluctuations in demand and supply gas 21 can be considered, such as machine learning models like neural network models or decision tree models, statistical models, plant models based on historical data, or numerical analysis models based on physical laws. However, the present invention is not limited to methods for estimating fluctuations in demand and supply gas.

[0086] If it is difficult to obtain or predict fluctuations in demand or supplied gas 21, it may be assumed that the current demand and state variables of the supplied gas 21 (such as gas component concentration and flow rate) remain constant. Furthermore, if the gas consumer's requested concentration of the product gas fluctuates, the control unit 15 may be configured to obtain or predict fluctuations in the concentration of the relevant gas component.

[0087] Next, in processing step S15, the control unit 15 determines whether the operation of the gas customer's equipment 200 can continue. As described above, even after an abnormality occurs, the control unit 15 determines whether the flow rate of the product gas 26 supplied to the gas customer and the concentration of each gas component can meet the gas customer's demand or its predicted value. By using the predicted value of gas demand to determine whether the operation of the gas customer's equipment 200 can continue, it is possible to determine whether operation can continue for a period from the present to the future. Therefore, the gas customer's equipment 200 and the gas concentration control device 100 can be operated safely in the future.

[0088] In determining whether operation can continue, the concentration of the gas component of the mixed gas that can be output by multiple gas separators, including the gas separator where the malfunction occurred (average hydrogen concentration of adjustment gases 23-25), and the concentration of the gas component of the mixed gas requested by the gas consumer (hydrogen concentration of product gas 26) or its predicted value are used. Alternatively, the flow rate of the mixed gas that can be output by multiple gas separators, including the gas separator where the malfunction occurred (total flow rate of adjustment gases 23-25), and the flow rate of the mixed gas requested by the gas consumer (flow rate of product gas 26) or its predicted value are used. Alternatively, both concentration and flow rate may be used.

[0089] For example, the control unit 15 compares and evaluates the production volume and gas component concentration of the product gas 26 after an abnormality occurs with the demand volume, required concentration, or predicted values ​​of the product gas 26 required by the gas consumer's equipment 200, including future demand. The control unit 15 determines that operation can be continued if the production volume and gas component concentration of the product gas 26 after the abnormality occurs can be produced with an error less than a preset threshold by comparing them with the demand volume, required concentration, or predicted values. These thresholds are stored in the ROM 32 or non-volatile storage 36.

[0090] Conversely, the control unit 15 determines that operation cannot be continued if the error exceeds a threshold. Alternatively, if the output of the buffer tank 4 is included and the production volume of product gas 26 and the concentration of gas components after the abnormality occurs fall below a preset threshold, the control unit 15 calculates the time during which operation can be continued based on the remaining amount of product gas 26 in the buffer tank 4. The control unit 15 may then determine to continue operating the gas consumer's equipment 200 for the amount of time during which operation can be continued.

[0091] Next, in processing step S16, the control unit 15 transmits the result of the determination of whether or not operation can be continued in processing step S15 to the gas customer's equipment 200 and display device 16. In addition, if the NO determination in processing step S12 is made, the control unit 15 notifies the gas customer's equipment 200 and display device 16 that there is no abnormality in the gas concentration control device 100 equipment.

[0092] If there are updates to the target values ​​such as the demand amount and required concentration of the product gas 26 requested by the gas consumer's equipment 200, the control unit 15 may receive the updated target values ​​from the gas consumer's equipment 200 during this processing step. If the control unit 15 receives the updated target values, it will perform the determination of whether or not to continue operation in processing step S15 again.

[0093] <Second Embodiment> Next, the display screen of the gas concentration control device according to the second embodiment of the present invention will be described with reference to Figure 10. Figure 10 shows an example of a display screen for a gas concentration control device according to a second embodiment of the present invention. Figure 10 shows an example of a screen displayed on either or both the display device 16 of the gas concentration control device 100 shown in Figure 1, and the display device (not shown) of the gas consumer's equipment 200. The same applies to the display screen of the gas concentration control device 100A.

[0094] The notification screen 300 shown in Figure 10 displays information (equipment abnormality information 301) regarding the equipment of the gas concentration control device 100, which was determined to have an abnormality in processing step S11. The notification screen 300 also displays the determination result 302 of whether operation can be continued in processing step S15, the remaining amount of product gas 26 in the buffer tank 4 303, the operating continuation time 304 calculated in processing step S15, and the target values ​​305 (hydrogen concentration, gas flow rate) required for the current product gas 26. It is desirable to display one or more of the following on the notification screen 300: equipment abnormality information 301, determination result 302 of whether operation can be continued, remaining amount in the tank 303, operating continuation time 304, and target values ​​305 for the product gas.

[0095] Furthermore, the notification screen 300 may be provided with a button 311 that can instruct the gas consumer's equipment 200 to continue operation, and a button 312 that can instruct it to stop operation. The administrator can decide whether to continue operation separately from the result of the operation continuation determination calculated in step S15. A button 313 may also be provided for adjusting the target value required for the current product gas 26. When button 313 is pressed, for example, the gas consumer's equipment 200 adjusts the target value required for the product gas 26 based on the gas consumer's usage of the product gas 26. Then, the display of the gas component concentration (e.g., hydrogen concentration) and the gas flow rate of the product gas 26 in the target value 305 on the notification screen 300 is updated.

[0096] This notification screen 300 allows at least one administrator of the gas concentration control device 100, or the administrator of the gas customer's equipment 200, to decide whether or not to continue operating the gas customer's equipment 200 based on the information displayed on the screen.

[0097] The present invention is not limited to the embodiments described above, and various other modifications and applications are possible as long as they do not depart from the gist of the invention as described in the claims. For example, the embodiments described above are detailed and specific in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those comprising all the components described. Furthermore, it is possible to add, replace, or delete other components in the configuration of each embodiment.

[0098] Furthermore, some or all of the above configurations, functions, and processing units may be implemented in hardware, for example, by designing them as integrated circuits. Broadly defined processor devices such as FPGAs (Field Programmable Gate Arrays) and ASICs (Application Specific Integrated Circuits) may be used as hardware.

[0099] Furthermore, in the embodiments described above, the control lines and information lines shown are those deemed necessary for explanatory purposes, and not all control lines and information lines are necessarily shown in the actual product. In practice, it can be assumed that almost all components are interconnected. [Explanation of Symbols]

[0100] 1-3…Gas separation device, 4…Buffer tank, 5,6…Compressor, 7-9…Control valve, 10,11…Control valve, 12-14…Sensor, 15…Control unit, 16…Display device, 17…Input device, 21…Supply gas, 22…Residual gas, 23-25…Adjusted gas, 26…Product gas, 30…Computer, 31…CPU, 32…ROM, 33…RAM, 100,100A…Gas concentration control device, 200…Gas consumer equipment, 300…Notification screen

Claims

1. Multiple gas separation devices that adjust the concentration of any gas component contained in the mixed gas and output the adjusted mixed gas, The system includes a control device that controls the concentration of the gas components and the flow rate of the mixed gas output from the gas separation device in accordance with the demand of the gas consumer, and also detects the occurrence of an abnormality in the gas separation device. When the control device detects an abnormality in the gas separation device, it controls the output of the gas separation devices that are not experiencing abnormalities, and uses the mixed gas output from multiple gas separation devices, including the one experiencing the abnormality, to adjust the concentration of the gas components and the flow rate of the mixed gas supplied to the gas consumer to meet the demand. Gas concentration control device.

2. The system includes a buffer tank that stores and outputs at least a portion of the mixed gas output by the multiple gas separation devices, When the control device detects an abnormality in the gas separation device, it controls the output of the buffer tank and the gas separation device that is not experiencing an abnormality, thereby adjusting the concentration of the gas components in the mixed gas supplied to the gas consumer and the flow rate of the mixed gas to meet the demand. The gas concentration control device according to claim 1.

3. The control device is Even after detecting an abnormality in the gas separation device, the system determines whether the gas customer's equipment can continue operating based on whether the concentration of the gas components in the mixed gas supplied to the gas customer and the flow rate of the mixed gas can meet the gas customer's demand. Depending on the result of the determination of whether operation can be continued, the gas separation device where the malfunction occurred or the equipment of the gas consumer will be stopped, and the output of the buffer tank and the gas separation device where no malfunction occurred will be controlled. The gas concentration control device according to claim 2.

4. The control device is If the determination result indicates that the gas consumer's equipment should continue operating, the malfunctioning gas separation device will be stopped, and the mixed gas output from the buffer tank and the gas separation device that is not malfunctioning will be used to supply mixed gas that meets the gas consumer's demand. The gas concentration control device according to claim 3.

5. The control device is If the determination result indicates that the gas customer's equipment cannot continue operating, the determination result that operation cannot continue is notified to the gas customer's equipment. Until the equipment of the gas consumer is shut down, the output of the buffer tank and the gas separation device that is not malfunctioning is controlled to reduce the flow rate of the mixed gas to zero while satisfying the concentration of the gas components of the mixed gas as requested by the gas consumer. The gas concentration control device according to claim 3.

6. The control device is The system acquires or predicts the future demand of the gas consumer and determines whether the gas consumer's equipment can continue operating after detecting an abnormality in the gas separation device, based on whether the concentration of the gas components in the mixed gas supplied to the gas consumer and the flow rate of the mixed gas can meet the gas consumer's demand or its predicted value. The gas concentration control device according to claim 3.

7. The control device is If the concentration of the gas component in the mixed gas requested by the gas consumer differs from the concentration of the gas component in the mixed gas output from the malfunctioning gas separator, the error between the concentration of the gas component in the mixed gas supplied to the gas consumer and the concentration of the gas component in the mixed gas requested by the gas consumer is reduced by mixing the mixed gas output from the malfunctioning gas separator with either or both of the mixed gas output from the gas separator that is not malfunctioning and the mixed gas in the buffer tank. The gas concentration control device according to claim 2.

8. The buffer tank is installed in parallel with the gas pipeline that supplies the mixed gas output by the multiple gas separation devices to the gas consumer's equipment. When the concentration of the gas component in the mixed gas requested by the gas consumer changes, the mixed gas output from the gas separation device is mixed with the mixed gas in the buffer tank. The gas concentration control device according to claim 2.

9. The control device outputs information including one or more of the following to either a display device connected to the control device and / or a display device connected to the gas consumer's equipment: the gas separation device in which an abnormality was detected, the result of determining whether the gas consumer's equipment can continue to operate, the remaining amount of the mixed gas in the buffer tank, and the remaining operating time. The gas concentration control device according to claim 3.

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