Hydrogen Supply System

Abstract

A hydrogen supply system (100) comprises: a hydrogen production unit (101) that produces hydrogen; a hydrogen boosting unit (102) that boosts the hydrogen produced by the hydrogen production unit (101) up to a pressure that enables the hydrogen to be supplied to a gas grid; a grid gas draw-in unit (103) that draws in grid gas from a gas grid (901); a hydrogen concentration adjustment unit (104) that prepares a mixed gas such that the hydrogen concentration will not exceed an allowable hydrogen concentration specified by the gas grid (901); and a mixed gas returning unit (105) that supplies the mixed gas to the gas grid.

Description

[Technical field]

[0001] The present invention relates to a hydrogen supply system that makes it possible to supply hydrogen to a gas grid at a hydrogen concentration equal to or lower than a prescribed level when supplying hydrogen to a gas grid that is permitted to be contaminated with hydrogen. [Background technology]

[0002] Compared to fossil fuels, hydrogen is a clean energy source that does not emit carbon dioxide when burned. For this reason, it has attracted attention as one of the clean energy sources for combating global warming, and technological development is underway regarding the production, transportation, and use of hydrogen. In light of this, it has been proposed to supply hydrogen produced by electrolysis of water using renewable energy sources, or by reforming natural gas, to gas pipelines that allow hydrogen to be mixed in. In this case, it is expected that the hydrogen concentration near the hydrogen supply point will exceed the limit stipulated for the gas grid, making it impossible to supply the desired amount of hydrogen.

[0003] Furthermore, the following Patent Document 1 proposes a method of supplying hydrogen to a gas grid by mixing hydrogen with fossil fuel gases such as LP gas or natural gas so as to meet city gas standards. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-169357 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the invention described in Patent Document 1, fossil fuel gas is newly mixed in to supply hydrogen. Therefore, the invention described in Patent Document 1 significantly increases the supply cost. Therefore, an object of the present invention is to prevent the hydrogen concentration from exceeding a specified value set for the gas grid while suppressing an increase in costs when hydrogen produced as clean energy is supplied to the gas grid. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the hydrogen supply system of the present invention includes a hydrogen production unit that produces hydrogen, a hydrogen pressure boosting unit that boosts the pressure of the hydrogen produced by the hydrogen production unit to a pressure at which the hydrogen can be supplied to a gas grid, and The above a grid gas inlet for drawing in grid gas from the gas grid; A mixed gas of hydrogen produced in the hydrogen production unit and grid gas drawn in from the gas grid, Below the allowable hydrogen concentration specified by the gas grid Adjusted a hydrogen concentration adjusting unit that adjusts the hydrogen concentration of the mixed gas and a mixed gas return unit that supplies the mixed gas to the gas grid. the hydrogen concentration adjustment unit includes a grid gas hydrogen concentration receiving unit that receives the hydrogen concentration in the grid gas from the grid gas inlet unit; a produced hydrogen flow rate measuring unit that measures the flow rate of hydrogen produced by the hydrogen production unit; a grid gas flow rate calculation unit that calculates a grid gas flow rate from the flow rate of hydrogen produced by the hydrogen production unit such that the mixed gas has an allowable hydrogen concentration equal to or lower than the allowable hydrogen concentration specified for the gas grid; a grid gas flow rate command unit that commands the grid gas flow rate calculated by the grid gas flow rate calculation unit; a gas mixing unit that mixes a designated amount of grid gas supplied from the grid gas inlet unit with hydrogen produced by the hydrogen production unit; and a mixed gas supply unit that supplies the mixed gas mixed by the gas mixing unit to the mixed gas return unit. It is characterized by: a grid gas supply unit that supplies grid gas to the hydrogen grid; a grid gas intake unit that draws in grid gas from the gas grid; a hydrogen concentration adjustment unit that adjusts a mixed gas of hydrogen produced by the hydrogen production unit and grid gas drawn in from the gas grid to an allowable hydrogen concentration or less specified by the gas grid; and a mixed gas return unit that supplies the mixed gas to the gas grid, wherein the grid gas intake unit comprises a grid gas hydrogen concentration measurement unit that measures the hydrogen concentration in the grid gas; a grid gas hydrogen concentration communication unit that transmits data on the hydrogen concentration in the grid gas to the hydrogen concentration adjustment unit; a grid gas flow rate receiving unit that receives the grid gas flow rate calculated by the hydrogen concentration adjustment unit; a grid gas flow rate adjustment unit that adjusts and draws in grid gas; and a grid gas supply unit that supplies grid gas to the hydrogen concentration adjustment unit. Other means will be described in the description of the embodiment of the invention. Effect of the Invention

[0007] According to the present invention, when hydrogen produced as clean energy is supplied to a gas grid, it is possible to supply the hydrogen so as not to exceed a specified hydrogen concentration value set for the gas grid while suppressing increases in costs. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram of a hydrogen supply system according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram of a hydrogen supply system according to a second embodiment. [Diagram 3] FIG. 3 is an explanatory diagram of a hydrogen supply system according to a third embodiment. [Figure 4] FIG. 4 is an explanatory diagram of a hydrogen supply system according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. Note that the same components are denoted by the same reference numerals, and if the description is repeated, the description may be omitted. In addition, the present invention is not limited to the following examples.

[0010] First Embodiment FIG. 1 is an explanatory diagram illustrating a hydrogen supply system 100 according to the first embodiment. The hydrogen supply system 100 described in the first embodiment includes a hydrogen production unit 101, a hydrogen boosting unit 102, a grid gas intake unit 103, a hydrogen concentration adjustment unit 104, and a mixed gas return unit 105. The hydrogen supply system 100 is connected to a gas grid 901 and supplies hydrogen to the gas grid 901. At least a blended gas of natural gas and hydrogen flows through the gas grid 901. The blended gas may be referred to as a mixed gas.

[0011] The hydrogen production unit 101 produces hydrogen. The hydrogen pressure boosting unit 102 boosts the pressure of the hydrogen produced by the hydrogen production unit 101 to a pressure that can be supplied to the gas grid 901, and supplies the hydrogen to the hydrogen concentration adjustment unit 104. The grid gas drawing unit 103 draws in grid gas from the gas grid 901 and supplies it to the hydrogen concentration adjustment unit 104. The hydrogen concentration adjustment unit 104 adjusts the mixed gas to an allowable hydrogen concentration or lower specified by the gas grid 901. The mixed gas return unit 105 supplies the mixed gas adjusted by the hydrogen concentration adjustment unit 104 to the gas grid 901.

[0012] Here, the grid gas inlet 103 and the mixed gas return unit 105 are connected to a gas grid 901. Note that a mixed gas (grid gas) of natural gas and hydrogen, such as city gas, exists in the gas grid 901. An upper limit on the hydrogen concentration is set in the gas grid 901 from the viewpoint of preventing hydrogen embrittlement of the gas grid and to use existing natural gas utilization facilities.

[0013] The hydrogen production unit 101 produces hydrogen 2 to be supplied to the gas grid 901. Here, the hydrogen 2 to be produced may be determined by predicting the hydrogen demand amount and determining the production flow rate, or may be produced by producing the amount of hydrogen instructed by the gas grid manager, and it is preferable that either is determined in consideration of the hydrogen demand. Here, the method of producing hydrogen by the hydrogen production unit 101 includes, for example, a method of producing hydrogen by electrolysis of water using electricity generated by renewable energy such as solar power generation or wind power generation, a method of producing hydrogen by shift reaction of carbon monoxide generated when gasifying coal and then separating carbon dioxide, and a method of producing hydrogen by steam reforming of natural gas, but is not limited to any of these. In addition, in order to realize carbon-free, if carbon dioxide is generated in the production process, it is preferable to capture the carbon dioxide and convert it into a valuable resource or store it.

[0014] Hydrogen 2 produced in the hydrogen production unit 101 is boosted in the hydrogen boosting unit 102 to a pressure that allows it to be supplied to the gas grid 901. The pressure that can be supplied to the gas grid 901 varies depending on the location on the gas grid 901 to which hydrogen is to be supplied, and is 0 to 0.1 MPaG for a low pressure gas grid, 0.1 to 1.0 MPaG for a medium pressure gas grid, and 1.0 MPaG or higher for a high pressure gas grid, and varies depending on the point at which hydrogen is to be supplied.

[0015] The hydrogen 2 is pressurized and then supplied to the hydrogen concentration adjusting unit 104. In addition, a grid gas supply unit 103 connected to the gas grid 901 supplies grid gas 1 present in the gas grid 901 to the hydrogen concentration adjusting unit 104.

[0016] Next, when grid gas 1 and hydrogen 2 are supplied, hydrogen concentration adjustment unit 104 mixes these two gases to produce mixed gas 3. Here, hydrogen concentration adjustment unit 104 adjusts the hydrogen concentration of the mixed gas by changing the grid gas flow rate so that the hydrogen concentration does not exceed the upper limit value of the hydrogen concentration defined by gas grid 901. Here, the upper limit value of the hydrogen concentration defined by gas grid 901 is also called the allowable hydrogen concentration. The grid gas flow rate is changed because the hydrogen production unit 101 needs to supply an amount of hydrogen that takes into account the demand for hydrogen.

[0017] The mixed gas 3 adjusted in the hydrogen concentration adjusting unit 104 is supplied to the gas grid 901 through the mixed gas returning unit 105 .

[0018] The hydrogen supply system 100 of this embodiment makes it possible to supply the produced hydrogen at a hydrogen concentration equal to or lower than a specified value set in the gas grid 901.

[0019] Second Embodiment In the second embodiment, an example of a method of operating the grid gas inlet unit 103, which is one of the components of the hydrogen supply system 100 of the present invention, will be described. Figure 2 shows a configuration diagram of the hydrogen supply system 100, illustrating the components of the grid gas inlet unit 103 in detail.

[0020] As shown in FIG. 2, the grid gas intake unit 103 includes a grid gas hydrogen concentration measurement unit 1031, a grid gas hydrogen concentration communication unit 1032, a grid gas flow rate receiving unit 1033, a grid gas flow rate adjustment unit 1034, and a grid gas supply unit 1035, and is connected to the hydrogen concentration adjustment unit 104 in the hydrogen supply system 100 and the gas grid 901.

[0021] The grid gas hydrogen concentration measurement unit 1031 measures the hydrogen concentration in the grid gas. The grid gas hydrogen concentration communication unit 1032 transmits data on the hydrogen concentration in the grid gas to the hydrogen concentration adjustment unit 104. The grid gas flow rate reception unit 1033 receives the grid gas flow rate calculated by the hydrogen concentration adjustment unit 104. The grid gas flow rate adjustment unit 1034 adjusts and draws in the grid gas. The grid gas supply unit 1035 supplies grid gas to the hydrogen concentration adjustment unit 104.

[0022] First, the grid gas hydrogen concentration measurement unit 1031 measures the hydrogen concentration in the grid gas. The grid gas hydrogen concentration communication unit 1032 transmits the measured grid gas hydrogen concentration data 201 to the hydrogen concentration adjustment unit 104. Here, the grid gas hydrogen concentration data 201 is used to determine the grid gas flow rate. The measurement interval in the grid gas hydrogen concentration measurement unit 1031 and the communication interval in the grid gas hydrogen concentration communication unit 1032 are not limited, but are preferably set to 5 minutes or less in consideration of responding to fluctuations in the hydrogen concentration in the grid gas.

[0023] Next, the hydrogen concentration adjuster 104 determines a grid gas flow rate that will result in a hydrogen concentration specified for the gas grid 901, based on the grid gas hydrogen concentration data 201 and the amount of hydrogen produced. The grid gas flow rate command data 202 determined by the hydrogen concentration adjuster 104 is transmitted to a grid gas flow rate receiver 1033 by a grid gas flow rate command unit 1044. The grid gas flow rate adjuster 1034 adjusts the flow rate of the grid gas based on the grid gas flow rate command data 202 received by the grid gas flow rate receiver 1033.

[0024] A method for calculating the grid gas flow rate by the hydrogen concentration adjuster 104 will be described in the third embodiment. Similarly, the interval at which the grid gas flow rate receiver 1033 receives data is preferably set to 5 minutes or less, similar to the communication interval of the grid gas hydrogen concentration communicator 1032.

[0025] A grid gas flow rate adjusting unit 1034 adjusts the grid gas flow rate drawn from the gas grid 901 to the value of the grid gas flow rate command data 202 received by a grid gas flow rate receiving unit 1033. Then, a grid gas supplying unit 1035 supplies grid gas 1 to the hydrogen concentration adjusting unit 104. Thereafter, as described in the first embodiment, the hydrogen concentration adjusting unit 104 mixes the grid gas 1 with the hydrogen 2 produced by the hydrogen producing unit 101. The mixed gas 3 adjusted by the hydrogen concentration adjusting unit 104 is supplied to the gas grid 901 through a mixed gas returning unit 105.

[0026] By using the hydrogen supply system 100 equipped with the grid gas inlet unit 103 of this embodiment, it is possible to keep the hydrogen concentration in the mixed gas adjusted by the hydrogen concentration adjustment unit 104 below the specified value of the gas grid 901, even if the hydrogen concentration in the grid gas fluctuates.

[0027] Third embodiment In the third embodiment, an example of a method of operating the hydrogen concentration adjusting unit 104, which is one of the components of the hydrogen supply system 100 of the present invention, will be described. Fig. 3 shows a configuration diagram of the hydrogen supply system 100, illustrating in detail the components of the hydrogen concentration adjusting unit 104 in Fig. 2.

[0028] 3, the hydrogen concentration adjusting unit 104 includes a grid gas hydrogen concentration receiving unit 1041, a produced hydrogen flow rate measuring unit 1042, a grid gas flow rate calculating unit 1043, a grid gas flow rate command unit 1044, a gas mixing unit 1045, and a mixed gas supplying unit 1046. The hydrogen concentration adjusting unit 104 is connected to the hydrogen boosting unit 102 and the grid gas intake unit 103 in the hydrogen supply system 100.

[0029] The grid gas hydrogen concentration receiving unit 1041 receives the hydrogen concentration in the grid gas from the grid gas drawing unit 103. The produced hydrogen flow rate measuring unit 1042 measures the flow rate of hydrogen produced by the hydrogen production unit 101. The grid gas flow rate calculation unit 1043 calculates a grid gas flow rate from the flow rate of hydrogen produced by the hydrogen production unit 101 such that the mixed gas has an allowable hydrogen concentration or less specified by the gas grid 901. The grid gas flow rate command unit 1044 commands the grid gas flow rate calculated by the grid gas flow rate calculation unit 1043 to the grid gas drawing unit 103. The gas mixing unit 1045 mixes a designated amount of grid gas supplied from the grid gas drawing unit 103 with hydrogen produced by the hydrogen production unit 101. The mixed gas supply unit 1046 supplies the mixed gas mixed by the gas mixing unit 1045 to the mixed gas return unit 105.

[0030] The hydrogen concentration adjusting unit 104 calculates the grid gas flow rate for making the hydrogen concentration in the mixed gas 3 supplied to the gas grid 901 equal to or less than a specified value, using grid gas hydrogen concentration data 201, which is the hydrogen concentration in the grid gas, and produced hydrogen flow rate data 203. The grid gas hydrogen concentration data 201 is measured by the grid gas hydrogen concentration measuring unit 1031 described in the second embodiment, and is received by the grid gas hydrogen concentration receiving unit 1041 through the grid gas hydrogen concentration communication unit 1032. The produced hydrogen flow rate data 203 is data measured by the produced hydrogen flow rate measuring unit 1042. These two types of data are then sent to the grid gas flow rate calculating unit 1043. Here, the flow rate of the grid gas 1 drawn in by the grid gas drawing unit 103 needs to flexibly respond to the time-series fluctuations in the hydrogen flow rate produced by the hydrogen producing unit 101. If the transmission interval of the grid gas hydrogen concentration data 201 is slow and the determination of the grid gas flow rate is delayed, particularly when the produced hydrogen flow rate increases, the hydrogen concentration in the mixed gas 3 supplied to the gas grid 901 will exceed the specified value and the gas cannot be supplied. Therefore, it is preferable that the reception interval of the grid gas hydrogen concentration data 201 by the grid gas hydrogen concentration receiving unit 1041 used to determine the grid gas flow rate and the measurement interval of the produced hydrogen flow rate data 203 by the produced hydrogen flow rate measuring unit 1042 are set to 5 minutes or less.

[0031] The grid gas flow rate calculation unit 1043 calculates the grid gas flow rate by the following formula (1). G is the grid gas flow rate [Nm 3 / h], F H2.SUP is the hydrogen production flow rate [Nm 3 / h], x H2.SET is the target hydrogen concentration in the mixed gas [vol%], x H2.G is the grid gas hydrogen concentration [vol%]. Here, the target hydrogen concentration in the mixed gas x H2.SET is set to be equal to or less than the specified hydrogen concentration value set in the gas grid. Note that the method of calculating the grid gas flow rate is not limited to formula (1).

[0032] F G =(100-x H2.SET ) / (xH2.SET -x H2.G )×F H2.SUP (1) Here is an example of calculation using formula (1). First, assume that the gas grid 901 is provided with a hydrogen concentration regulation value of 20 vol.%, and the produced hydrogen flow rate is 100 Nm 3 / h, grid gas hydrogen concentration is 10 vol%, and target hydrogen concentration in the mixed gas is 20 vol%. Since it is preferable for hydrogen users to increase the hydrogen concentration in the gas grid 901 as much as possible, the target hydrogen concentration in the mixed gas is set to the specified hydrogen concentration value set in the gas grid 901 in this embodiment, but is not limited thereto. Substituting the above values ​​into equation (1), the flow rate of the grid gas drawn in by the grid gas drawing unit 103 is 800 Nm 3 / h.

[0033] As described above, the grid gas flow rate command data 202 calculated by the grid gas flow rate calculation unit 1043 is transmitted from the grid gas flow rate command unit 1044 to the grid gas flow rate receiving unit 1033, and the grid gas flow rate to be drawn in is adjusted by the grid gas flow rate adjustment unit 1034. Here, the data interval transmitted to the grid gas flow rate receiving unit 1033 is preferably set to 5 minutes or less, similar to the data reception interval of the grid gas hydrogen concentration receiving unit 1041 and the flow rate measurement interval of the produced hydrogen flow rate measurement unit 1042. The designated amount of grid gas 1 thus adjusted and hydrogen 2 produced by the hydrogen production unit 101 are mixed in the gas mixing unit 1045. When supplying the mixed gas to the gas grid 901, it is preferable that hydrogen does not exist in the mixed gas, so that the gas mixing unit 1045 preferably mixes hydrogen 2 and the grid gas by a method such as a pressure ratio mixing method, a gravimetric method, a flow rate mixing method, or a semi-gravimetric method, but the mixing method is not limited. The mixed gas 3 is then supplied from the mixed gas return unit 105 through the mixed gas supply unit 1046 to the gas grid 901 .

[0034] By providing the hydrogen supply system 100 with the hydrogen concentration adjustment unit 104 of the third embodiment, it is possible to keep the hydrogen concentration in the mixed gas adjusted by the hydrogen concentration adjustment unit 104 below the specified value of the gas grid 901, even when the produced hydrogen flow rate fluctuates.

[0035] Fourth embodiment In the fourth embodiment, an example of a method of operating the mixed gas return unit 105, which is one of the components of the hydrogen supply system 100 of the present invention, will be described. Fig. 4 shows a configuration diagram of the hydrogen supply system 100, illustrating in detail the components of the mixed gas return unit 105 in Fig. 3.

[0036] 3, the mixed gas return unit 105 includes a mixed gas flow rate measurement unit 1051, a grid gas flow rate balance management unit 1052, a mixed gas gas grid supply unit 1053, and a return gas calorific value measurement unit 1054. The mixed gas return unit 105 is connected to the hydrogen concentration adjustment unit 104 and the gas grid 901 in the hydrogen supply system 100.

[0037] The mixed gas flow rate measuring unit 1051 measures the flow rate of the mixed gas. The grid gas flow rate balance management unit 1052 compares the grid gas flow rate in the mixed gas, which is obtained by subtracting the produced hydrogen flow rate measured by the produced hydrogen flow rate measuring unit 1042 from the mixed gas flow rate measured by the mixed gas flow rate measuring unit 1051, with the grid gas flow rate commanded to the grid gas flow rate adjustment unit 1034 by the grid gas flow rate command unit 1044, to manage the grid gas balance. The mixed gas grid supply unit 1053 supplies the mixed gas to the gas grid 901.

[0038] As described in the first to third embodiments, the hydrogen 2 produced by the hydrogen production unit 101 has its hydrogen concentration adjusted by the grid gas intake unit 103 and the hydrogen concentration adjustment unit 104. Here, since grid gas 1 is drawn from the gas grid 901 and then supplied to the gas grid 901 again, the hydrogen supplier and the gas grid operator need to manage the material balance of the grid gas 1. By managing the balance of the grid gas flow rate, when the hydrogen supplier draws in the grid gas, the gas grid operator can set a fee structure different from that of existing grid gas users.

[0039] As shown in the fourth embodiment, the mixed gas 3 supplied from the hydrogen concentration adjusting unit 104 is measured by the mixed gas flow rate measuring unit 1051 and transmitted as mixed gas flow rate data 204 to the grid gas flow rate balance management unit 1052. The grid gas flow rate balance management unit 1052 calculates the grid gas material balance using the mixed gas flow rate data 204, the produced hydrogen flow rate data 203 measured by the produced hydrogen flow rate measuring unit 1042, and the grid gas flow rate command data 202 determined by the grid gas flow rate calculation unit 1043, and manages that the grid gas 1 drawn from the gas grid 901 is normally returned to the gas grid 901 in the same amount. Here, there is a time difference between each measurement data due to the operation time of each process and the length of the gas piping, and it is assumed that the material balance does not match accurately with data at the same time, so it is preferable to manage the flow rate balance with a certain time span. The status of this grid gas material balance management is also transmitted to the gas grid operator 106, and both parties are constantly aware of it.

[0040] Finally, the mixed gas is supplied to the gas grid 901 by using, for example, a blower in the mixed gas gas grid supply unit 1053. It is desirable that the connection port to the gas grid 901 has a structure that allows the return gas to be diffused within the gas grid 901 as much as possible.

[0041] By using the hydrogen supply system 100 equipped with the mixed gas return unit 105 of this embodiment and managing the material balance of the grid gas drawn in and the grid gas returned to the gas grid 901, it is possible to set a fee structure different from that of existing grid gas users.

[0042] The hydrogen supply device supplies the mixed gas 3 to the gas grid 901 by the methods described in the first to third embodiments and this embodiment, but it is necessary to obtain income by charging according to the amount of hydrogen supplied in the mixed gas 3. As a method of charging, for example, there is a method of calculating the charged amount on a calorie basis.

[0043] Specifically, a return gas calorific value measuring unit 1054 is provided in the mixed gas return unit 105 in Fig. 4. The return gas calorific value measuring unit 1054 measures the amount of heat [MJ / m 3 ], flow rate [m 3 The return gas calorific value measuring unit 1054 is a means for calculating the calorific value of hydrogen in the supplied mixed gas from the return gas calorific value [kcal / h] and the supply time [h]. Based on the calorific value calculated by the return gas calorific value measuring unit 1054, the amount to be charged can be determined and paid to the supplier.

[0044] A gas consumption calorific value measuring unit is provided on the hydrogen utilization device (not shown). The gas consumption calorific value measuring unit measures the calorific value [MJ / m 3 ], flow rate [m 3 This is a means of calculating the calorific value of gas used based on the gas consumption [kWh / h] and supply time [h]. By measuring the calorific value of gas used with the gas consumption calorific value measuring unit, it is possible to determine the usage fee and charge the user for payment.

[0045] (Modification) The present invention is not limited to the above-described embodiment, and includes various modified examples. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to those having all of the configurations described. It is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0046] The above configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware such as an integrated circuit. The above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program that realizes each function. Information such as the program, table, file, etc. that realizes each function can be stored in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as a flash memory card or a DVD (Digital Versatile Disk).

[0047] In each embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it may be considered that almost all components are connected to each other. [Explanation of symbols]

[0048] 1. Grid Gas 2. Hydrogen 3. Mixed gas (blended gas) 100 Hydrogen Supply System 101 Hydrogen Production Department 102 Hydrogen booster 103 Grid gas inlet 1031 Grid gas hydrogen concentration measurement unit 1032 Grid gas hydrogen concentration communication unit 1033 Grid gas flow rate receiver 1034 Grid gas flow rate adjustment unit 1035 Grid Gas Supply 104 Hydrogen concentration adjustment unit 1041 Grid gas hydrogen concentration receiver 1042 Produced hydrogen flow rate measurement unit 1043 Grid gas flow rate calculation unit 1044 Grid gas flow command unit 1045 Gas Mixing Section 1046 Mixed gas supply unit 105 Mixed gas return section 1051 Mixed gas flow rate measuring unit 1052 Grid Gas Flow Balance Management Unit 1053 Mixed gas gas grid supply unit 106 Gas Grid Operators 201 Grid gas hydrogen concentration data 202 Grid gas flow command data 203 Hydrogen production flow rate data 204 Mixed gas flow rate data 901 Gas Grid

Claims

1. A hydrogen production unit that produces hydrogen; a hydrogen pressure boosting unit that boosts the pressure of the hydrogen produced by the hydrogen production unit to a pressure at which the hydrogen can be supplied to a gas grid; a grid gas inlet for drawing in grid gas from the gas grid; a hydrogen concentration adjusting unit that adjusts a mixed gas of hydrogen produced by the hydrogen production unit and grid gas drawn from the gas grid to a hydrogen concentration equal to or lower than an allowable hydrogen concentration defined by the gas grid; a mixed gas return unit for supplying the mixed gas to the gas grid; Equipped with The hydrogen concentration adjusting unit is a grid gas hydrogen concentration receiving unit that receives a hydrogen concentration in the grid gas from the grid gas inlet; A produced hydrogen flow rate measuring unit that measures the flow rate of hydrogen produced by the hydrogen production unit; a grid gas flow rate calculation unit that calculates a grid gas flow rate based on the flow rate of hydrogen produced by the hydrogen production unit so that the mixed gas has an allowable hydrogen concentration equal to or lower than a tolerable hydrogen concentration defined for the gas grid; a grid gas flow rate command unit that commands the grid gas flow rate calculated by the grid gas flow rate calculation unit; A gas mixing unit that mixes a designated amount of grid gas supplied from the grid gas inlet unit with hydrogen produced by the hydrogen production unit; a mixed gas supply unit that supplies the mixed gas mixed by the gas mixing unit to the mixed gas return unit; A hydrogen supply system comprising:

2. 2. The hydrogen supply system according to claim 1, The mixed gas return section includes: a mixed gas flow rate measuring unit that measures a flow rate of the mixed gas; a grid gas flow rate balance management unit that manages the balance of grid gas by comparing a grid gas flow rate in the mixed gas, which is obtained by subtracting the produced hydrogen flow rate measured by the produced hydrogen flow rate measurement unit from the mixed gas flow rate measured by the mixed gas flow rate measurement unit, with a grid gas flow rate commanded by the grid gas flow rate command unit; A hydrogen supply system comprising:

3. 3. The hydrogen supply system according to claim 2, The mixed gas return section includes: Further comprising a return gas calorific value measuring unit for measuring the calorific value of hydrogen in the return gas; This hydrogen supply system is characterized by the above.

4. A hydrogen production unit that produces hydrogen; a hydrogen pressure boosting unit that boosts the pressure of the hydrogen produced by the hydrogen production unit to a pressure at which the hydrogen can be supplied to a gas grid; a grid gas inlet for drawing in grid gas from the gas grid; a hydrogen concentration adjusting unit that adjusts a mixed gas of hydrogen produced by the hydrogen production unit and grid gas drawn from the gas grid to a hydrogen concentration equal to or lower than an allowable hydrogen concentration defined by the gas grid; a mixed gas return unit for supplying the mixed gas to the gas grid; Equipped with The grid gas inlet comprises: a grid gas hydrogen concentration measuring unit for measuring a hydrogen concentration in the grid gas; a grid gas hydrogen concentration communication unit that transmits data on the hydrogen concentration in the grid gas to the hydrogen concentration adjustment unit; a grid gas flow rate receiving unit that receives the grid gas flow rate calculated by the hydrogen concentration adjusting unit; a grid gas flow rate regulator that regulates and draws in grid gas; a grid gas supply unit for supplying a grid gas to the hydrogen concentration adjustment unit; A hydrogen supply system comprising:

5. The hydrogen concentration adjustment unit is a grid gas hydrogen concentration receiving unit that receives a hydrogen concentration in the grid gas from the grid gas inlet; A produced hydrogen flow rate measuring unit that measures the flow rate of hydrogen produced by the hydrogen production unit; a grid gas flow rate calculation unit that calculates a grid gas flow rate based on the flow rate of hydrogen produced by the hydrogen production unit so that the mixed gas has an allowable hydrogen concentration equal to or lower than a tolerable hydrogen concentration defined for the gas grid; a grid gas flow rate command unit that commands the grid gas flow rate calculated by the grid gas flow rate calculation unit; A gas mixing unit that mixes a designated amount of grid gas supplied from the grid gas inlet unit with hydrogen produced by the hydrogen production unit; a mixed gas supply unit that supplies the mixed gas mixed by the gas mixing unit to the mixed gas return unit; The hydrogen supply system according to claim 4, further comprising:

6. A hydrogen supply system according to any one of claims 1 to 5, The gas grid is supplied with a blend of natural gas and hydrogen. A hydrogen supply system comprising:

7. A hydrogen supply system according to any one of claims 1 to 5, The hydrogen production unit produces hydrogen by any one of the following methods: electrolyzing water using electricity generated by renewable energy, reforming natural gas, and gasifying coal and generating hydrogen through a shift reaction. A hydrogen supply system comprising:

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