Gas separation system

Abstract

The present invention provides a gas separation system capable of supplying hydrogen gas to a consumer at a low device cost. The gas separation system according to the present invention is provided with a gas separation device (5) and a gas separation system management unit (11). The gas separation device (5) is provided with: a gas acquisition unit (7) that acquires a mixed gas (4); a gas separation unit (8) that uses a hydrogen separation membrane to separate a gas for use by the consumer (6) and a return gas to a pipeline (1) from the mixed gas (4); a gas supply unit (9) that supplies the gas for use by the consumer (6), which has been separated by the gas separation unit (8), to the consumer (6); a gas discharge unit (10) that discharges the return gas; and a measuring instrument (12) that measures the physical quantity of the gas. The gas separation system management unit (11) stores information about the consumer (6), and an output item is set according to the type and application of the gas for use by the consumer (6). The output item is the physical quantity of the gas output by the gas separation device (5). The measuring instrument (12) differs in installation position and output item to be measured according to the type and application of the gas for use by the consumer (6).

Description

Gas Separation Systems

[0001] The present invention relates to a gas separation system for separating hydrogen from a mixed gas containing hydrogen.

[0002] The Ministry of the Environment launched a "Demonstration Project for the Production of Renewable Energy Electrolytic Hydrogen and the Supply and Utilization of Hydrogen Mixed Gas" in 2019 (https: / / www.env.go.jp / press / 106873.html). In this project, hydrogen is produced by electrolysis of water using electricity generated by wind power, and this hydrogen is mixed with a simulated gas equivalent to city gas to produce a hydrogen mixed gas. The produced mixed gas is then supplied to the usage location via gas pipes. The mixed gas can be used directly in water heaters, gas stoves, etc.

[0003] When hydrogen is injected into an existing grid (pipe network) for natural gas or city gas, and a mixture of natural gas and hydrogen or city gas and hydrogen is supplied through the grid, in addition to conventional natural gas or city gas consumers, consumers who directly use the mixed gas (mixed gas consumers) will be connected to the grid. It is also expected that hydrogen consumers who use hydrogen gas will connect to the grid and use hydrogen gas from the mixed gas.

[0004] An example of an apparatus for separating hydrogen gas from a mixed gas and supplying it is described in Patent Document 1. Patent Document 1 describes an apparatus that separates hydrogen gas from city gas at one or more locations in a pipeline network, then returns at least a portion of the separated city gas to the pipeline network, thereby separating the hydrogen gas from the city gas and supplying it directly to equipment that uses hydrogen gas as fuel, such as a fuel cell. By returning the separated gas to the pipeline network, this apparatus can accommodate consumers who use conventional city gas combustion appliances without modifying their existing systems. When separating hydrogen gas, the Wobbe Index (WI) and Burning Velocity Index (CP) of the separated gas are each controlled to fall within a predetermined range.

[0005] Japanese Patent Application Laid-Open No. 2002-213695

[0006] When supplying mixed gas (e.g., a natural gas and hydrogen mixed gas) to natural gas consumers, mixed gas consumers, and hydrogen consumers using an existing gas grid, it is necessary to adjust the component concentration and calorific value (heat value) of the gas to meet the respective requirements. To provide gas that meets the requirements of each consumer, measuring instruments are required to measure values ​​such as the concentration of hydrogen in the mixed gas, the concentration of coexisting substances (substances other than hydrogen contained in the mixed gas), and the calorific value and density of the gas. However, such measuring instruments, particularly hydrogen concentration meters, are expensive. Each consumer must have a gas separation device equipped with such measuring instruments, which incurs high equipment costs. For this reason, a gas separation device that requires fewer measuring instruments and can reduce equipment costs is desired.

[0007] An object of the present invention is to provide a gas separation system that can supply hydrogen gas to consumers at low equipment costs.

[0008] The gas separation system according to the present invention includes a plurality of gas separation devices and a gas separation system management unit connected to the plurality of gas separation devices. Each of the gas separation devices includes a gas acquisition unit, which is a pipe for acquiring a mixed gas containing hydrogen gas from a pipeline through which the mixed gas flows; a gas separation unit having a separation membrane permeable to hydrogen gas and using the separation membrane to separate the mixed gas into a gas to be used by a consumer and a gas to be returned to the pipeline; a gas supply unit, which is a pipe for supplying the gas to be used by the consumer obtained by separating the mixed gas from the mixed gas by the gas separation unit; a gas discharge unit, which is a pipe for discharging the gas to be returned to the pipeline obtained by separating the mixed gas from the mixed gas by the gas separation unit; and a measuring instrument installed in at least one of the pipes of the gas acquisition unit, the gas supply unit, and the gas discharge unit, for measuring the physical quantities of the gas flowing through the installed pipes. The gas separation system management unit stores information about the consumer, and output items are set according to the type and use of gas used by the consumer. The output items are the physical quantities of the gas output by the gas separation device. The measuring instruments vary in their installation locations and the output items they measure depending on the type and purpose of gas used by the consumer.

[0009] According to the present invention, it is possible to provide a gas separation system that can supply hydrogen gas to consumers at low equipment costs.

[0010] FIG. 1 is a diagram showing a gas separation system according to a first embodiment of the present invention, and a consumer to which gas is supplied by the gas separation system according to this embodiment. FIG. 2 is a diagram showing a schematic configuration of a gas separation device. FIG. 3 is an explanatory diagram showing an example of the configuration of a gas separation device according to a consumer. FIG. 4 is a diagram showing an example of the results of a simulation in which a mixed gas is separated by two-stage separation membranes. FIG. 5 is a diagram showing an example of a screen displayed on a display device owned by a consumer. FIG. 6 is a diagram showing an example of a management screen displayed on a display device provided in a gas separation system according to a fifth embodiment of the present invention.

[0011] The gas separation system according to the present invention can separate hydrogen from a mixed gas containing hydrogen. The mixed gas is a gas obtained by mixing hydrogen gas with either natural gas or city gas. In this invention, output items (gas physical quantities) are set according to the consumer, and the number of measuring instruments for measuring the gas physical quantities is reduced, thereby reducing the cost of the equipment. In particular, hydrogen gas that meets the consumer's required specifications can be supplied to hydrogen gas consumers without the use of expensive hydrogen concentration meters.

[0012] A gas separation system according to an embodiment of the present invention will be described below with reference to the drawings. Hereinafter, an example will be described in which the mixed gas is a mixture of hydrogen gas and natural gas, and hydrogen gas will also be referred to simply as hydrogen. In the drawings used in this specification, identical or corresponding components are designated by the same reference numerals, and repeated description of these components may be omitted.

[0013] A gas separation system according to a first embodiment of the present invention will be described.

[0014] FIG. 1A is a diagram showing a gas separation system according to the present embodiment and a consumer to which gas is supplied by the gas separation system according to the present embodiment.

[0015] The gas separation system according to this embodiment includes a plurality of gas separation devices 5 and a gas separation system management unit 11 connected to these gas separation devices 5 .

[0016] The plurality of gas separation devices 5 are connected to the pipeline 1 and supply the gas flowing through the pipeline 1 to consumers 6. Fig. 1A shows, as an example, an example in which the gas separation system according to this embodiment includes three gas separation devices 5a, 5b, and 5c, and the gas separation devices 5a, 5b, and 5c supply gas to three consumers 6a, 6b, and 6c, respectively.

[0017] The consumer 6 uses the gas supplied from the gas separation device 5 as, for example, fuel or raw material.

[0018] Gas is supplied to the pipeline 1 from a hydrogen supply base 2 and a natural gas supply base 3, and a mixed gas 4 containing hydrogen gas and natural gas flows through the pipeline 1. The pipeline 1 is, for example, a piping system that constitutes an existing grid (pipe network) through which natural gas flows.

[0019] The configuration of the gas separation device 5 will be described.

[0020] 1B is a diagram schematically illustrating the configuration of the gas separation apparatus 5. The gas separation apparatus 5 includes a gas acquisition unit 7, a gas separation unit 8, a gas supply unit 9, a gas discharge unit 10, a measuring instrument 12, and a control unit 13.

[0021] The gas acquisition unit 7 is a pipe that acquires the mixed gas 4 from the pipeline 1, and is connected to the pipeline 1 and the gas separation unit 8. The mixed gas 4 acquired by the gas acquisition unit 7 from the pipeline 1 is also referred to as acquired gas. The gas acquisition unit 7 supplies the mixed gas 4 (acquired gas) to the gas separation unit 8.

[0022] The gas separation unit 8 includes a separation membrane, and uses the separation membrane to separate the mixed gas 4 into gas to be used by the consumer 6 and gas (surplus gas) to be returned to the pipeline 1. The gas to be used by the consumer 6 is separated from the mixed gas 4 by the gas separation unit 8. The separation membrane is a membrane that has a higher hydrogen gas permeation rate than the permeation rates of other gases, and an existing hydrogen separation membrane made of, for example, a ceramic membrane, a metal membrane, or a polymer membrane can be used. In this example, an example is described in which a polymer membrane modularized by bundling hollow fibers formed from a polymer material is used as the separation membrane.

[0023] The gas separation unit 8 includes a permeation section 8a where hydrogen gas that has permeated the separation membrane exists, and a non-permeation section 8b where gas that has not permeated the separation membrane exists. As will be described later, the gas separation unit 8 preferably includes two separation membranes (two-stage separation membranes).

[0024] The gas supply unit 9 is a pipe that delivers gas to the consumer 6, and is connected to the gas separation unit 8. The gas used by the consumer 6 is gas obtained by separating it from the mixed gas 4 by the gas separation unit 8.

[0025] The gas discharge unit 10 is a pipe that discharges excess gas obtained by the gas separation unit 8 separating it from the mixed gas 4, and is connected to the gas separation unit 8. The excess gas is the mixed gas 4 (gas not required by the consumer 6) remaining after the gas separation unit 8 has separated the gas to be used by the consumer 6. The gas discharge unit 10 is connected to the pipeline 1, and returns the excess gas from the gas separation unit 8 to the pipeline 1.

[0026] The installation location and the output items measured by the measuring instrument 12 vary depending on the type and purpose of gas used by the consumer 6. Specifically, the measuring instrument 12 is installed in at least one of the gas acquisition unit 7, the gas supply unit 9, and the gas discharge unit 10, and measures the physical quantity of the gas flowing through the pipe in which the measuring instrument 12 is installed. An existing measuring instrument can be used as the measuring instrument 12.

[0027] The control unit 13 controls the gas separation device 5 as described below.

[0028] The gas separation unit 8, the gas supply unit 9, and the gas discharge unit 10 may each include one or both of a valve and a compressor for controlling the gas pressure. The gas separation unit 8, the gas supply unit 9, and the gas discharge unit 10 may also include a heating unit for adjusting the temperature of the flowing gas, or a bypass flow path through which part of the flowing gas branches off. The control unit 13 controls such valves, compressors, and heating units.

[0029] The gas separation system management unit 11 shown in Fig. 1A will now be described. The gas separation system management unit 11 can be configured with a computer and includes a consumer information database 106 and a setting unit 101. The gas separation system management unit 11 can receive information related to the control of the control unit 13 (such as values ​​calculated by the control unit 13 to perform control and control operations performed by the control unit 13) and measurement values ​​of the measuring instrument 12 from the gas separation apparatus 5. The gas separation system management unit 11 can also include a display device 1021.

[0030] The customer information database 106 stores information about the customers 6 connected to the pipeline 1 as customer information.

[0031] The consumer information includes, for example, the type and use (purpose of use) of gas used by the consumer 6, the required specifications of the consumer 6 (values ​​required for the gas used by the consumer 6), and information on the gas-using equipment of the consumer 6. The required specifications of the consumer 6 include, for example, the density, calorific value (heat value), and component concentration of the gas.

[0032] The type of gas is one of the gases contained in the mixed gas 4 flowing through the pipeline 1 (natural gas or hydrogen in this embodiment), or the mixed gas 4 .

[0033] In this example, the use is as a fuel or raw material.

[0034] The component concentration is a condition value for the gas concentration, for example, the lower limit of the concentration of the gas used by the consumer 6, or the upper limit of the concentration of a coexisting gas (a gas other than the gas used by the consumer 6 that is contained in the mixed gas 4).

[0035] The information on the appliances used is information on the appliances that the customer 6 uses for gas, and includes, for example, the range of allowable heat quantity of the appliances.

[0036] In the setting unit 101, for each gas separation device 5, a consumer type, output items, and output target value are set according to the consumer 6 to which gas is supplied by the gas separation device 5. The consumer type, output items, and output target value are set based on consumer information stored in the consumer information database 106.

[0037] The consumer type includes the type and use of gas used by the consumer 6 .

[0038] The output items are physical quantities of the gas output by the gas separation device 5, such as density, calorific value (heat value), and component concentration. In this embodiment, since the mixed gas 4 is a gas in which hydrogen gas and natural gas are mixed, the component concentrations are, for example, the hydrogen concentration and the carbon dioxide concentration contained in the natural gas. The output items can be determined according to the consumer 6, and can be determined, for example, from the type and use of gas used by the consumer 6 and the required specifications of the consumer 6.

[0039] The output target value is a target value of an output item, i.e., a target value of a physical quantity of gas output by the gas separation device 5. The output target value can be determined according to the consumer 6, and can be determined, for example, based on the required specifications of the consumer 6 and information on the equipment used by the consumer 6.

[0040] In the setting unit 101, before the gas separation apparatus 5 is installed in the consumer 6, the consumer type, output items, and output target values ​​are set for each gas separation apparatus 5.

[0041] The gas separation device 5 has a configuration according to the gas used by the consumer 6. That is, the gas separation device 5 is configured based on the consumer type, output items, and output target values ​​set in the setting unit 101 of the gas separation system management unit 11.

[0042] The gas separation device 5 is configured based on the consumer type, output items, and output target values ​​corresponding to the consumer 6, and is installed between the consumer 6 and the pipeline 1. The measuring instrument 12 provided in the gas separation device 5 is capable of measuring the values ​​of the output items.

[0043] 2 is an explanatory diagram showing examples of the configuration of the gas separation device 5 according to the consumer 6. The multiple gas separation devices 5 installed in the pipeline 1 have different configurations depending on the gas used by the corresponding consumer 6. FIG. 2 shows examples of the configuration of the gas separation device 5 according to the consumer type, i.e., when the gas used by the consumer 6 is natural gas, when the mixed gas 4 is used, or when hydrogen gas is used.

[0044] For consumers 6 that use natural gas and consumers 6 that use mixed gas 4, the gas use in the consumer information is generally fuel, and the calorific value per unit volume (hereinafter also referred to as calorific value), which is a calorific value standard, is the required specification. Therefore, for consumers 6 that use natural gas and consumers 6 that use mixed gas 4, the output item is calorific value. The output target value is the target value for the calorific value of the gas, and is determined, for example, according to the required specification of the consumer 6 and information about the equipment used by the consumer 6 (information about the equipment used by the consumer 6 for gas).

[0045] In the gas separation unit 8, when the mixed gas 4 is separated using a separation membrane, the permeation unit 8a has a high hydrogen concentration, while the non-permeation unit 8b has a high concentration of methane, a major component of natural gas. Therefore, the gas obtained from the non-permeation unit 8b of the gas separation unit 8 included in the gas separation device 5 is provided to the natural gas consumer 6.

[0046] Therefore, in the gas separation apparatus 5 that supplies gas to natural gas consumers 6, a gas supply unit 9 is connected to the non-permeation section 8b of the gas separation unit 8, and a measuring instrument 12 is installed in the gas supply unit 9. This measuring instrument 12 is a gas calorimeter that measures the calorific value of the natural gas. A gas discharge unit 10 is connected to the permeation section 8a of the gas separation unit 8.

[0047] In the gas separation device 5 that supplies gas to a consumer 6 of the mixed gas 4, the relationship between the calorific value of the mixed gas 4 obtained from the pipeline 1 and the calorific value required by the consumer 6 determines whether the gas supply unit 9 that supplies gas to the consumer 6 is connected to the non-permeable section 8b or the permeable section 8a of the gas separation unit 8.

[0048] Hydrogen gas has a lower calorific value per unit volume than natural gas or methane gas, which is a major component of natural gas. Therefore, if the calorific value of the obtained mixed gas 4 is lower than the required specifications of the consumer 6, it can be determined that the mixed gas 4 contains excess hydrogen gas. In the gas separation device 5, the concentration of methane gas in the non-permeation section 8b is higher than the concentration of methane gas in the mixed gas 4.

[0049] Therefore, if a preliminary investigation reveals that the calorific value of the mixed gas 4 is smaller than the required specifications of the consumer 6, the gas from the non-permeation section 8b is provided to the consumer 6. That is, in the gas separation device 5 that supplies gas to the consumer 6 of the mixed gas 4, if the calorific value of the mixed gas 4 is smaller than the required specifications of the consumer 6, the gas supply section 9 is connected to the non-permeation section 8b of the gas separation section 8, and the gas discharge section 10 is connected to the permeation section 8a of the gas separation section 8.

[0050] On the other hand, if a preliminary investigation reveals that the calorific value of the mixed gas 4 is greater than the required specifications of the consumer 6, the gas in the permeation section 8a is supplied to the consumer 6. That is, in the gas separation device 5 that supplies gas to the consumer 6 of the mixed gas 4, if the calorific value of the mixed gas 4 is greater than the required specifications of the consumer 6, the gas supply section 9 is connected to the permeation section 8a of the gas separation section 8, and the gas discharge section 10 is connected to the non-permeation section 8b of the gas separation section 8. The gas in the permeation section 8a has a higher hydrogen concentration than the mixed gas 4.

[0051] The calorific value and hydrogen concentration of the acquired gas (the mixed gas 4 acquired by the gas acquisition unit 7 from the pipeline 1) may fluctuate. Therefore, whether the gas supply unit 9 is connected to the non-permeation unit 8b or the permeation unit 8a of the gas separation unit 8 does not need to be determined and fixed before the gas separation device 5 is installed in the pipeline 1, but may be switched during operation of the gas separation device 5.

[0052] For example, suppose that the pipe connected to the non-permeation section 8b of the gas separation unit 8 and the pipe connected to the permeation section 8a each branch into two, one branch serving as a gas supply unit 9 that supplies gas to the consumer 6, and the other branch serving as a gas discharge unit 10 that returns excess gas. Valves are installed in the branched pipes. The control unit 13 controls the opening and closing of these valves to change whether the branched pipe supplies gas to the consumer 6 or returns it to the pipeline 1. In this way, during operation, the gas separation device 5 can switch whether the gas supply unit 9 is connected to the non-permeation section 8b or the permeation section 8a, depending on the relationship between the calorific value of the obtained gas (mixed gas 4) and the calorific value required by the consumer 6.

[0053] As described above, in the gas separation device 5 that supplies gas to the consumer 6 of the mixed gas 4, it is determined whether the gas supply unit 9 is connected to the non-permeation unit 8b or the permeation unit 8a of the gas separation unit 8 based on the calorific value of the mixed gas 4 that is the acquired gas. For this reason, measuring instruments 12 are installed in three locations: the gas acquisition unit 7, the gas supply unit 9, and the gas discharge unit 10. These measuring instruments 12 are gas calorimeters that measure the calorific value of the gas.

[0054] In this way, in the gas separation device 5 that supplies gas to a consumer 6 of the mixed gas 4, one of the gas supply unit 9 and the gas discharge unit 10 is installed in the permeation unit 8a, and the other is installed in the non-permeation unit 8b, and measuring instruments 12 are installed in the gas acquisition unit 7, the gas supply unit 9, and the gas discharge unit 10.

[0055] In the gas separation device 5 that supplies gas to a consumer 6 of the mixed gas 4, the control unit 13 inputs the output items and output target values ​​from the gas separation system management unit 11, and uses the measurement values ​​of a measuring instrument 12 installed in the gas acquisition unit 7, etc. to decide whether to supply the gas from the permeable section 8a or the gas from the non-permeable section 8b to the consumer 6, and can change the gas supplied to the consumer 6 by switching whether the gas supply unit 9 is connected to the non-permeable section 8b or the permeable section 8a.

[0056] In a gas separation apparatus 5 that supplies gas to a hydrogen gas consumer 6, a gas supply unit 9 is connected to a permeation unit 8a of a gas separation unit 8, and a measuring instrument 12 is installed in the gas supply unit 9. A gas discharge unit 10 is connected to a non-permeation unit 8b of the gas separation unit 8.

[0057] Consumers 6 that use hydrogen gas are divided into consumers 6 that use hydrogen gas as a raw material for chemical products, etc., and consumers 6 that use hydrogen gas as fuel for hydrogen boilers, hydrogen vehicles, etc. The gas separation device 5 that supplies gas to each consumer 6 will be described below.

[0058] When hydrogen gas is used as a raw material, the calorific value of the supplied gas is not an issue, and the required specification is the concentration of the hydrogen gas. Therefore, for consumers 6 who use hydrogen gas as a raw material, the required specification is the concentration of the hydrogen gas.

[0059] Consumers 6 who use hydrogen gas as a raw material require high-concentration hydrogen, so gas with a high hydrogen concentration is supplied to these consumers 6. For this reason, a hydrogen concentration meter may be installed as the measuring instrument 12 in the gas separation device 5 that supplies gas to consumers 6 who use hydrogen gas as a raw material, according to the required specifications. However, there are only a limited number of measuring instruments that can continuously measure the hydrogen concentration in a mixed gas containing three or more components, and expensive equipment such as a gas chromatograph is required.

[0060] Therefore, in order to reduce the equipment cost of the gas separation system, it is preferable to use a density meter or a carbon dioxide concentration meter, which is a general-purpose measuring instrument, as the measuring instrument 12 of the gas separation apparatus 5. In this embodiment, the density meter or the carbon dioxide concentration meter is used as the measuring instrument 12 to control the gas separation apparatus 5.

[0061] In this example, the gas separation device 5 is assumed to supply to the consumer 6 with two components, hydrogen and carbon dioxide, and an output target value is set to provide high-concentration hydrogen to the consumer 6. Because a density meter or a carbon dioxide concentration meter is used as the measuring instrument 12, the output item is the density or carbon dioxide concentration of the gas supplied to the consumer 6. The density meter and carbon dioxide concentration meter, which are the measuring instrument 12, measure the density and carbon dioxide concentration of the gas flowing through the gas supply unit 9, respectively.

[0062] For example, when the output item is density, the control unit 13 of the gas separation device 5 sets the target value of the gas density ρ, which is the output target value, to a value that satisfies formula (1), and controls the gas separation device 5 so that the density ρ becomes the output target value. By such control, the density ρ of the gas supplied to the consumer 6 becomes a value that satisfies formula (1).

[0063]

[0064] On the left side of equation (1), the density ρ of the gas is the density (kg / m) of the gas flowing through the gas supply unit 9. ３ On the right-hand side, the subscripts ρ and C indicate the components in the gas (hydrogen and carbon dioxide), and ρ is the density (kg / m ３) and C is the target component concentration (vol%) of the component (hydrogen) indicated by the subscript based on the required specifications of the consumer 6. In addition, in the formula (1), the density ρ Ｈ２ and the density of carbon dioxide ρ ＣＯ２ The values ​​used are those determined as the physical properties of pure gases.

[0065] If the density of the gas supplied to the consumer 6 is high, this indicates that the hydrogen concentration of this gas is low. For this reason, the control unit 13 of the gas separation device 5 controls the gas separation device 5 by operating valves and compressors through feedback control using known technology to change the operating conditions of the gas separation device 5 (e.g., gas flow rate and pressure) so that the density ρ of the gas supplied to the consumer 6 decreases to reach the output target value (i.e., so that equation (1) is satisfied). Through this control, the control unit 13 can increase the hydrogen concentration of the gas supplied to the consumer 6 to reach the target hydrogen concentration.

[0066] In addition, when the output item is carbon dioxide concentration, the control unit 13 of the gas separation device 5 controls the gas separation device 5 in accordance with the above-mentioned assumption, assuming that the components other than carbon dioxide in the obtained gas (mixed gas 4) are hydrogen, so that the hydrogen concentration becomes the target hydrogen concentration based on the required specifications of the consumer 6.

[0067] If the carbon dioxide concentration of the gas supplied to the consumer 6 is high, this indicates that the hydrogen concentration of this gas is low. For this reason, the control unit 13 of the gas separation device 5 controls the gas separation device 5 so as to reduce the carbon dioxide concentration of the gas flowing through the gas supply unit 9 measured by the measuring instrument 12. Specifically, the control unit 13 controls the gas separation device 5 by operating valves and compressors through feedback control using known technology to change the operating conditions of the gas separation device 5 (for example, the gas flow rate and pressure), thereby reducing the carbon dioxide concentration of the gas supplied to the consumer 6 and increasing the hydrogen concentration to reach the target hydrogen concentration.

[0068] Consumers 6 that use hydrogen gas as fuel use hydrogen as fuel for, for example, hydrogen vehicles or hydrogen boilers, and require hydrogen at a high concentration above a specified value, just like consumers 6 that use hydrogen gas as a raw material. For this reason, the gas separation device 5 that supplies gas to consumers 6 that use hydrogen gas as a fuel can have the same configuration as the gas separation device 5 that supplies gas to consumers 6 that use hydrogen gas as a raw material.

[0069] Furthermore, a consumer 6 that uses hydrogen gas as fuel may set an upper limit on the concentration of coexisting components (components other than hydrogen contained in the mixed gas 4) in the required specifications. In such cases, it is necessary to measure the concentration of the coexisting components, so the concentration of the coexisting components may be set as an output item. Although this increases the cost of the device, the gas separation device 5 may be provided with a measuring instrument 12 in the gas supply unit 9 that measures the concentration of the coexisting components. A known measuring instrument can be used as the measuring instrument 12 that measures the concentration of the coexisting components.

[0070] In this way, the gas separation device 5 that supplies gas to the consumer 6 that uses hydrogen gas as fuel can provide the consumer 6 with gas with a high hydrogen concentration.

[0071] The reason why the gas supplied from the gas separation device 5 to the consumer 6 is assumed to consist of two components, hydrogen and carbon dioxide, will be explained below. Consumers 6 that use hydrogen often require high-concentration hydrogen. For this reason, it is preferable that the gas separation unit 8 has two separation membranes connected in series, and separates the gas using these two stages of separation membranes to obtain high-concentration hydrogen. Separation of gas using separation membranes utilizes the difference in the permeation speed of each gas through the separation membrane.

[0072] Figure 3 shows an example of the results of a simulation of separating a mixed gas using two-stage separation membranes, showing the volumetric flow rates of the components contained in the mixed gas before separation, the gas immediately after permeating the first-stage separation membrane, and the gas after permeating the second-stage separation membrane.

[0073] In this simulation, existing simulation technology was used to perform calculations to simulate gas separation using two-stage separation membranes based on the permeation rates of gas components contained in the mixed gas through the separation membrane. The mixed gas was a mixture of natural gas and 20 vol% hydrogen gas. In this simulation, the separation membrane was assumed to be composed of a module (polymer membrane module) consisting of a bundle of hollow fibers made of polymer material.

[0074] Before separation, the mixed gas contains hydrogen (H), methane (CH), carbon dioxide (CO), and ethane (CH), etc. In the mixed gas before separation, the concentration (proportion) of methane is high, followed by the concentration of hydrogen.

[0075] Immediately after the mixed gas is separated by the first-stage separation membrane (before separation by the second-stage separation membrane), the gas that has permeated the separation membrane has a high concentration of hydrogen, which has a high permeation rate, and a low concentration of methane and other gases, which have a low permeation rate. Carbon dioxide, which has a higher permeation rate than methane, has a high concentration. Gases such as methane, which have a low permeation rate, do not permeate the separation membrane and move to the non-permeation section 8b.

[0076] After the mixed gas is separated by the second-stage separation membrane, the concentration of methane and other gases with low permeation rates is significantly reduced in the gas that has permeated this separation membrane, while the concentrations of hydrogen and carbon dioxide with high permeation rates are high.

[0077] 3, when the mixed gas 4 is separated using two-stage separation membranes, the gas that has permeated the two-stage separation membranes has low concentrations of components other than hydrogen and carbon dioxide, and can be considered to be a gas consisting of two components, hydrogen and carbon dioxide. Therefore, when hydrogen gas is supplied to a consumer 6, it can be assumed that the gas supplied to the consumer 6 consists of two components, hydrogen and carbon dioxide.

[0078] As described above, the gas separation system of this embodiment sets an appropriate output target value according to the consumer 6 and is equipped with a measuring instrument 12 according to this output target value, thereby making it possible to supply the gas required by the consumer 6 (e.g., hydrogen gas, natural gas, and a mixed gas of hydrogen gas and natural gas) to the consumer 6 at low equipment costs.

[0079] In the gas separation system according to the second embodiment of the present invention, the gas separation system management unit 11 calculates an estimated value of the concentration of hydrogen contained in the gas to be supplied to a consumer 6 that uses hydrogen gas (a consumer 6 that uses hydrogen gas as a raw material or fuel) from the density or carbon dioxide concentration of the gas to be supplied to the consumer 6. The gas separation system according to the present embodiment can provide the consumer 6 with an estimated value of the hydrogen concentration, which is a required specification of the consumer 6.

[0080] As described in Example 1, when high-concentration hydrogen is provided to the consumer 6, it can be assumed that the gas supplied to the consumer 6 by the gas separation device 5 consists of two components: hydrogen and carbon dioxide. Therefore, the gas separation system management unit 11 can calculate the concentration of hydrogen flowing through the gas supply unit 9 (i.e., the hydrogen contained in the gas supplied to the consumer 6) using the following equation (2) from the density of the gas flowing through the gas supply unit 9 measured by the measuring instrument 12. Furthermore, the gas separation system management unit 11 can calculate the concentration of hydrogen flowing through the gas supply unit 9 using the following equation (3) from the carbon dioxide concentration of the gas flowing through the gas supply unit 9 measured by the measuring instrument 12.

[0081]

[0082]

[0083] In equations (2) and (3), ρ is the density (kg / m) of the gas flowing through the gas supply unit 9. ３ ) and ρ Ｈ２ is the density (kg / m) of hydrogen flowing through the gas supply unit 9 ３ ) and ρ ＣＯ２ is the density (kg / m) of carbon dioxide flowing through the gas supply unit 9 ３ ) and C Ｈ２ is the concentration (vol%) of hydrogen flowing through the gas supply unit 9, and C ＣＯ２ is the concentration (vol %) of carbon dioxide flowing through the gas supply unit 9.

[0084] The gas separation system management unit 11 calculates the hydrogen concentration C Ｈ２ can be transmitted to the customer 6.

[0085] In Example 3 of the present invention, control performed by the gas separation system according to this example will be described. This control is executed by the control unit 13 of the gas separation apparatus 5. The gas separation system according to this example can execute control tailored to the requirements of each consumer 6. Furthermore, even when the component concentrations of the mixed gas 4 flowing through the pipeline 1 change, the gas separation system according to this example can execute follow-up control with little delay in response to this change.

[0086] Below, the control performed by the control unit 13 will be described for each of the consumer types shown in FIG. 2 (natural gas consumer 6, mixed gas 4 consumer 6, and hydrogen gas consumer 6).

[0087] The control unit 13 supplies gas to be used by the consumer 6 to the consumer 6 by controlling one or more of the flow rate and pressure of the gas supplied to the gas separation unit 8 (i.e., the gas flowing through the gas acquisition unit 7), the gas flowing through the gas supply unit 9, and the gas flowing through the gas discharge unit 10. The control unit 13 can operate valves and compressors by feedback control using known technology to execute control to change the flow rate and pressure of the gas according to the required specifications of the consumer 6.

[0088] For a consumer 6 that uses natural gas, if the value of the calorific value, which is an output item, falls below the required specifications of the consumer 6, the gas separation device 5 is controlled to reduce the hydrogen concentration of the gas supplied to the consumer 6. The value of the output item is measured by a measuring instrument 12. Specifically, by reducing the pressure in the permeation section 8a of the gas separation unit 8 or by increasing the pressure of the gas supplied to the gas separation unit 8, the amount of hydrogen gas that permeates the separation membrane is increased, thereby reducing the hydrogen concentration of the gas supplied to the consumer 6 (i.e., the gas present in the non-permeation section 8b of the gas separation unit 8). In addition, by reducing the flow rate of the mixed gas 4 (acquired gas) acquired from the pipeline 1 by the gas acquisition unit 7, the gas flow rate relative to the area of ​​the separation membrane can be reduced, thereby reducing the hydrogen concentration of the gas supplied to the consumer 6.

[0089] For consumers 6 that use the mixed gas, the output item is calorific value, so if the calorific value of the acquired gas (mixed gas 4) is smaller than the required specifications of the consumer 6, the gas present in the non-permeable section 8b is supplied to the consumer 6, and if the calorific value of the acquired gas is larger than the required specifications of the consumer 6, the gas present in the permeable section 8a is supplied to the consumer 6. The value of the output item is measured by a measuring instrument 12.

[0090] When the calorific value of the acquired gas and the calorific value of the gas flowing through the gas supply unit 9 are both smaller than the required specifications of the consumer 6, the gas separation device 5 is controlled to reduce the hydrogen concentration of the gas supplied to the consumer 6. Specifically, by reducing the pressure in the permeation unit 8a of the gas separation unit 8 or by increasing the pressure of the gas supplied to the gas separation unit 8, the amount of hydrogen gas permeating the separation membrane is increased, thereby reducing the hydrogen concentration of the gas supplied to the consumer 6 (i.e., the gas present in the non-permeation unit 8b of the gas separation unit 8). In addition, by reducing the flow rate of the mixed gas 4 (acquired gas) acquired by the gas acquisition unit 7 from the pipeline 1, the gas flow rate relative to the area of ​​the separation membrane can be reduced, and the hydrogen concentration of the gas supplied to the consumer 6 can also be reduced.

[0091] If the calorific value of the acquired gas and the calorific value of the gas flowing through the gas supply unit 9 are both greater than the required specifications of the consumer 6, the gas separation device 5 is controlled so that the hydrogen concentration of the gas supplied to the consumer 6 is increased.

[0092] For a consumer 6 that uses hydrogen gas, if the value of the density, which is an output item, exceeds the required specification of the consumer 6, or if the value of the carbon dioxide concentration, which is an output item, exceeds the required specification of the consumer 6, the gas separation device 5 is controlled to increase the hydrogen concentration of the gas supplied to the consumer 6. The value of the output item is measured by a measuring instrument 12. Specifically, by lowering the pressure in the permeation section 8a of the gas separation unit 8 or by increasing the pressure of the gas supplied to the gas separation unit 8, the amount of hydrogen gas that permeates the separation membrane is increased, thereby increasing the hydrogen concentration of the gas supplied to the consumer 6 (i.e., the gas present in the permeation section 8a of the gas separation unit 8). In addition, by reducing the flow rate of the mixed gas 4 (acquired gas) acquired from the pipeline 1 by the gas acquisition unit 7, the gas flow rate relative to the area of ​​the separation membrane can be reduced, thereby increasing the hydrogen concentration of the gas supplied to the consumer 6.

[0093] The gas separation system according to this embodiment is provided with a measuring instrument 12 in the gas acquisition unit 7, so that even if the component concentrations of the gas (mixed gas 4) acquired from the pipeline 1 change, gas that meets the specifications required by the consumer 6 can be supplied to the consumer 6. The measuring instrument 12 installed in the gas acquisition unit 7 is a calorimeter, a density meter, or a carbon dioxide concentration meter. The control unit 13 also performs such control.

[0094] The component concentrations of the gas acquired by the gas separation device 5 from the pipeline 1 change over time depending on the amount of gas supplied from the natural gas supply base 3 and the hydrogen supply base 2, and the component concentrations and amount of gas returned from nearby gas separation devices 5. The control unit 13 of the gas separation device 5 changes the flow rate or pressure of one or more of the gas supplied to the gas separation unit 8 (i.e., the gas flowing through the gas acquisition unit 7), the gas flowing through the gas supply unit 9, and the gas flowing through the gas discharge unit 10, so that the output target value becomes a predetermined specified value. The method for changing the flow rate or pressure of such gas can be the above-mentioned method or a known method.

[0095] At this time, the magnitude of change per unit time (time change width) of the flow rate and pressure can be set based on the magnitude of change per unit time (time change width) of the measurement value of the measuring instrument 12 installed in the gas acquisition unit 7. A large time change width of the measurement value of the measuring instrument 12, i.e., a large time change width of the measurement value of the gas (mixed gas 4) acquired from the pipeline 1, indicates that the component concentration of the mixed gas 4 is changing rapidly in a short period of time. For this reason, the time change width of the flow rate and pressure can be determined by multiplying the time change width of the measurement value of the measuring instrument 12 by a predetermined coefficient.

[0096] By performing such control, the control unit 13 of the gas separation device 5 can perform tracking control with little delay in response to changes in the component concentration of the mixed gas 4 flowing through the pipeline 1.

[0097] In this embodiment, an example of a screen displayed on a display device provided in a consumer facility 6 by a gas separation system according to an embodiment of the present invention will be described.

[0098] A gas separation system according to an embodiment of the present invention can provide information about the gas being supplied to a consumer 6. In the gas separation system according to an embodiment of the present invention, the gas separation device 5 transmits data obtained by the measuring instrument 12 and the control unit 13 to the gas separation system management unit 11, and the gas separation system management unit 11 transmits the data received from the gas separation device 5 to the consumer 6.

[0099] The consumer 6 has a display device, receives the data transmitted from the gas separation system management unit 11, and displays it on the display device.

[0100] 4 is a diagram showing an example of a screen displayed on a display device owned by the consumer 6. This display screen 1000 displays a consumer type 1001, the type of gas supplied to the consumer 6 (provided gas type 1002), output items 1004, and an estimated hydrogen concentration 1003. The estimated hydrogen concentration 1003 is calculated by the gas separation system management unit 11 using the hydrogen concentration C Ｈ２ (the concentration of hydrogen flowing through the gas supply unit 9).

[0101] Furthermore, the display screen 1000 displays the current measured value 1005 of the density of the gas (acquired gas) acquired from the pipeline 1 by the gas separation system according to an embodiment of the present invention, a time history 1006 of the measured value of the density of the acquired gas, a required specification 1008 of the output target value of the gas being supplied to the consumer 6, and a time history 1007 of the output target value of the gas being supplied to the consumer 6.

[0102] The display screen 1000 may also display an alert display section 1009 that displays an alert if the gas being supplied to the consumer 6 does not meet the consumer 6's required specifications 1008, and a button 1010 for stopping operation of the gas separation device 5, and may also display the electricity consumed by the gas separation system and the electricity cost for the gas separation system.

[0103] For example, when the gas being supplied to the consumer 6 exceeds the required specifications 1008 of the consumer 6, the alert display unit 1009 displays an alert by changing the display. The change in the display of the alert display unit 1009 is, for example, lighting up or flashing.

[0104] The consumer 6 can stop the operation of the gas separation device 5, for example, by clicking button 1010. For example, when button 1010 is clicked, a valve provided in the gas separation device 5 closes, and the supply of gas from the gas separation device 5 to the consumer 6 is stopped.

[0105] In the gas separation system according to Example 5 of the present invention, the gas separation system management unit 11 is provided with a display device, and data obtained by the measuring instrument 12 and control unit 13 of the gas separation apparatus 5 can be displayed on this display device. The gas separation system according to this example can provide the manager of the gas separation system with information about the operating status of the gas separation apparatus 5 and the gas being supplied to the consumer 6. The manager of the gas separation system can check whether the gas separation apparatus 5 is operating normally.

[0106] An example of a screen displayed by the display device 1021 included in the gas separation system according to this embodiment will be described below. The gas separation system management unit 11 includes the display device 1021, and displays, for example, the management screen shown below on the display device 1021.

[0107] FIG. 5 is a diagram showing an example of a management screen 1020 displayed on the display device 1021 provided in the gas separation system according to this embodiment.

[0108] The management screen 1020 displays the gas separation apparatuses 5 (5a, 5b, 5c) connected to the pipeline 1. The management screen 1020 displays a consumer type 1001, a type of supplied gas 1002, an output item 1004, and an estimated hydrogen concentration 1003 for each gas separation apparatus 5 (5a, 5b, 5c), and further displays an output target value 1011, a configuration 1012 of the gas separation apparatus 5, and a measured value (supplied gas value 1013) of the gas being supplied to the consumer 6. The estimated hydrogen concentration 1003 is calculated based on the hydrogen concentration C calculated by the gas separation system management unit 11 as described in Example 4. Ｈ２ (concentration of hydrogen flowing through the gas supply unit 9). The provided gas value 1013 is a measurement value of the measuring instrument 12 installed in the gas supply unit 9.

[0109] Furthermore, the management screen 1020 may display the time history of the provided gas value 1013, the time history of the estimated hydrogen concentration 1003, the operating status 1016 of the gas separation device 5, and information about the gas flowing through the pipeline 1. The operating status 1016 of the gas separation device 5 displays, for example, that the gas separation device 5 is in operation, or that the gas being supplied to the consumer 6 exceeds the required specifications 1008 of the consumer 6.

[0110] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to embodiments that include all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations.

[0111] 1...Pipeline, 2...Hydrogen supply base, 3...Natural gas supply base, 4...Mixed gas, 5, 5a, 5b, 5c...Gas separation device, 6, 6a, 6b, 6c...Consumer, 7...Gas acquisition section, 8...Gas separation section, 8a...Permeation section, 8b...Non-permeation section, 9...Gas supply section, 10...Gas discharge section, 11...Gas separation system management section, 12...Measuring instrument, 13...Control section, 101...Setting section, 106...Consumer information database, 1000...Display screen, 1001...Consumer type, 10 02...Type of provided gas, 1003...Estimated hydrogen concentration, 1004...Output items, 1005...Current measured value of density of obtained gas, 1006...Time history of measured value of density of obtained gas, 1007...Time history of output target value, 1008...Required specifications for output target value, 1009...Alert display unit, 1010...Button, 1011...Output target value, 1012...Configuration of gas separation device, 1013...Provided gas value, 1016...Operating status, 1020...Management screen, 1021...Display device.

Claims

1. A system comprising: a plurality of gas separation devices; and a gas separation system management unit connected to the plurality of gas separation devices, each of the gas separation devices comprising: a gas acquisition unit which is a piping for acquiring a mixed gas containing hydrogen gas from a pipeline through which the mixed gas flows; a gas separation unit which is provided with a separation membrane which allows hydrogen gas to permeate, and which separates from the mixed gas into a gas to be used by a consumer and a gas to be returned to the pipeline using the separation membrane; a gas supply unit which is a piping for supplying the gas to be used by the consumer obtained by separating the mixed gas by the gas separation unit to the consumer; and a gas discharge unit which is a piping for discharging the gas to be returned to the pipeline obtained by separating the mixed gas by the gas separation unit; and a measuring instrument which is installed in at least one of the pipings of the gas acquisition unit, the gas supply unit, and the gas discharge unit, and which measures a physical quantity of the gas flowing through the installed piping, wherein the gas separation system management unit stores information about the consumer, and output items are set according to the type and use of gas used by the consumer, The gas separation system is characterized in that the output items are physical quantities of gas output by the gas separation device, and the measuring instruments have different installation locations and the output items they measure depending on the type and purpose of gas used by the consumer.

2. The gas separation system of claim 1, wherein the gas separation unit comprises a permeable section in which hydrogen gas that has permeated the separation membrane is present, and a non-permeable section in which gas that does not permeate the separation membrane is present, the mixed gas contains natural gas, and for the consumer that uses natural gas, the output item is heat quantity, the gas supply unit is connected to the non-permeable section, the gas exhaust unit is connected to the permeable section, and the measuring instrument is a calorimeter and is installed in the gas supply unit.

3. The gas separation system of claim 1, wherein the gas separation unit comprises a permeable section in which hydrogen gas that has permeated the separation membrane is present, and a non-permeable section in which gas that does not permeate the separation membrane is present, and for the consumer that uses the mixed gas, the output item is heat quantity, one of the gas supply unit and the gas discharge unit is connected to the permeable section, and the other is connected to the non-permeable section, and the measuring instrument is a calorimeter and is installed in the gas supply unit, the gas discharge unit, and the gas acquisition unit.

4. The gas separation system of claim 1, wherein the gas separation unit comprises a permeable section in which hydrogen gas that has permeated the separation membrane is present, and a non-permeable section in which gas that does not permeate the separation membrane is present, and for the consumer that uses hydrogen gas, the output item is density or carbon dioxide concentration, the gas supply unit is connected to the permeable section, the gas exhaust unit is connected to the non-permeable section, and the measuring instrument is a density meter or a carbon dioxide concentration meter and is installed in the gas supply unit.

5. The gas separation system according to claim 1, wherein the gas separation system management unit is provided with a display device, calculates the concentration of hydrogen flowing through the gas supply unit using the density or carbon dioxide concentration of the gas flowing through the gas supply unit measured by the measuring instrument, and displays the calculated hydrogen concentration on the display device.

6. The gas separation system of claim 4, wherein each of the gas separation devices is equipped with a control unit, and when the value of the output item measured by the measuring instrument exceeds the required specification of the consumer, the control unit increases the amount of hydrogen gas permeating through the separation membrane by changing the gas pressure or flow rate so as to increase the hydrogen concentration of the gas supplied to the consumer.

7. The gas separation system of claim 1, wherein each of the gas separation devices is equipped with a control unit, the gas acquisition unit is equipped with a calorimeter, a density meter, or a carbon dioxide concentration meter as the measuring instrument, the control unit changes the flow rate or pressure of one or more of the gas flowing through the gas acquisition unit, the gas flowing through the gas supply unit, and the gas flowing through the gas exhaust unit so that the value of the output item becomes a specified value, and the control unit sets the magnitude of change per unit time of the gas that changes the flow rate or pressure based on the magnitude of change per unit time of the measurement value of the measuring instrument installed in the gas acquisition unit.

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