Mixed gas grid maintenance system and mixed gas grid maintenance method

Abstract

To enable reduction of leakage risk and maintenance burden by determining an appropriate maintenance policy for a mixed gas grid.SOLUTION: A mixed gas grid maintenance system includes: a grid system information acquisition unit which acquires system information for a mixed gas pipeline; a grid operation information acquisition unit which acquires operation information for the mixed gas pipeline; a fluid analysis unit which calculates a hydrogen concentration distribution in each system of a gas grid by fluid analysis using the system information acquired by the grid system information acquisition unit and the operation information acquired by the grid operation information acquisition unit as inputs; a risk assessment unit which extracts a location with high hydrogen concentration as a high risk portion on the basis of the hydrogen concentration distribution calculated by the fluid analysis unit; and an output unit which outputs or displays a risk assessment result acquired by the risk assessment unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mixed gas grid maintenance system and a mixed gas grid maintenance method. [Background technology]

[0002] In order to achieve decarbonization, a project is underway to inject hydrogen into the pipeline network that serves as the existing gas grid for natural gas and other sources, and transport the hydrogen as a mixed gas. When hydrogen is transported as a mixed gas, it will be mixed with natural gas and hydrogen within the gas grid. Hydrogen has a smaller molecular size than methane, the main component of natural gas, and there is a greater risk of hydrogen leaking than with natural gas.

[0003] The ratio of natural gas to hydrogen (hydrogen concentration) in the gas grid is not always constant, but varies spatially and temporally due to factors such as the following: (Factor 1) Capital investment will be made in preparation for the transition, which will change the amount of hydrogen used and the amount of hydrogen that can be produced. (Factor 2) When using hydrogen obtained by electrolyzing water using surplus electricity, the amount produced is not constant but varies depending on the weather, time of day, and electricity usage.

[0004] In addition to grids that transport natural gas, there is also the possibility of pipelines for carbon dioxide capture being realized in the future. It is also possible to inject hydrogen into carbon dioxide gas grids, or to mix other gases such as carbon dioxide into natural gas grids and transport them as mixed gases. Even if the gas type in the existing grid is other than natural gas, the injection of hydrogen will increase concerns about leakage.

[0005] Because gas grids transport flammable gases, they must be properly maintained to prevent leaks and damage. However, gas grids that transport natural gas and city gas cover a wide area, making it difficult to constantly monitor and inspect the entire area.

[0006] Patent document 1 describes a technique for detecting leaks in pipes or pipelines by identifying patterns in a group of data values ​​acquired at measurement points to determine the possible presence of a leak in a measurement section of a flow-transporting object. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-521488 Summary of the Invention [Problem to be solved by the invention]

[0008] Because gas grids are located over a wide area, it is difficult to conduct leak assessments uniformly. Furthermore, mixed gas grids contain hydrogen, which is more susceptible to leaks than methane, which increases the inspection and maintenance burden. Therefore, it is necessary to establish an appropriate maintenance policy for mixed gas grids and reduce the risk of leaks and the maintenance burden. In particular, in the case of gas grids that transport mixed gases including hydrogen, the concentration of the mixed gases may change spatially and temporally, and different management methods are required compared to conventional gas grids that transport natural gas, etc.

[0009] An object of the present invention is to provide a mixed gas grid maintenance system and a mixed gas grid maintenance method that can solve problems that occur when transporting mixed gas to a grid. [Means for solving the problem]

[0010] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes multiple means for solving the above-mentioned problems, and one example thereof is a mixed gas grid maintenance system for determining a maintenance policy for a gas grid composed of mixed gas pipelines that transport mixed gas containing hydrogen. An example mixed gas grid maintenance system includes a grid system information acquisition unit that acquires system information of the mixed gas pipeline, a grid operation information acquisition unit that acquires operation information of the mixed gas pipeline, a fluid analysis unit that uses the system information acquired by the grid system information acquisition unit and the operation information acquired by the grid operation information acquisition unit as input and calculates the hydrogen concentration distribution within each system of the gas grid through fluid analysis, a risk assessment unit that extracts locations with high hydrogen concentrations as high-risk areas based on the hydrogen concentration distribution calculated by the fluid analysis unit, and an output unit that outputs or displays the risk assessment results obtained by the risk assessment unit. [Effects of the Invention]

[0011] According to the present invention, when operating a mixed gas grid for transporting hydrogen as a mixed gas, inspection and maintenance can be made more efficient, thereby reducing the maintenance burden. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a configuration diagram showing an example of a mixed gas grid maintenance system according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram showing an example of the hardware configuration of a mixed gas grid maintenance system according to a first embodiment of the present invention. [Figure 3] 3 is a flowchart showing an example of processing by the mixed gas grid maintenance system according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing an example of a display screen of the mixed gas grid maintenance system according to the first embodiment of the present invention. [Figure 5] 5 is a flowchart showing processing (modification 1) performed by the mixed gas grid maintenance system according to the first embodiment of the present invention. [Figure 6] 5 is a flowchart showing processing (modification 2) performed by the mixed gas grid maintenance system according to the first embodiment of the present invention. [Figure 7] 10 is a flowchart showing processing (Modification 3) performed by the mixed gas grid maintenance system according to the first embodiment of the present invention. [Figure 8] FIG. 10 is a configuration diagram showing an example of a mixed gas grid maintenance system according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a diagram showing an example of a display screen of the mixed gas grid maintenance system according to the second embodiment of the present invention. [Figure 10] FIG. 10 is a configuration diagram showing an example of a mixed gas grid maintenance system according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing an example of a display screen of the mixed gas grid maintenance system according to the third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] <First embodiment> A mixed gas grid maintenance system and a mixed gas grid maintenance method according to a first embodiment of the present invention will be described below with reference to FIGS.

[0014] [Configuration of mixed gas grid maintenance system] In this embodiment, the mixed gas grid maintenance system formulates a maintenance plan for a mixed gas grid in which a plurality of gas supply bases 2 and a plurality of gas usage bases 3 are connected to a gas pipeline 1, as shown in the display example of Fig. 4. The configuration of this mixed gas grid is shown in a reduced scale in Fig. 1 and other figures. The gas supply base 2 is a contact point that has the function of injecting gas into the pipeline 1 , and the gas utilization base 3 is a contact point that has the function of extracting gas from the pipeline 1 . Furthermore, in the case of a facility such as a storage facility that has the function of both extracting gas from a pipeline and returning gas to the pipeline, it is assumed that it has a gas supply base 2 and a gas usage base 3. Similarly, in the case of a facility that extracts gas from pipeline 1 and returns unwanted gas to pipeline 1, it is assumed that it has a gas supply base 2 and a gas usage base 3.

[0015] The mixed gas grid of this embodiment transports a mixture of natural gas and hydrogen through the pipeline 1. Hereinafter, the term "gas grid" used in this specification refers to a mixture of natural gas and hydrogen that is transported. However, a mixed gas grid that mixes natural gas and hydrogen is just one example, and as will be described later, natural gas and a gas other than hydrogen (such as carbon dioxide) may also be mixed as a mixed gas grid.

[0016] Fig. 1 is a diagram showing the system configuration of a mixed gas grid maintenance system 100 according to a first embodiment of the present invention. Note that, although this embodiment shows an example in which all of the components shown in Fig. 1 are used, it is not necessary to use all of them, and some of them may be used. 1 includes a fluid analysis unit 101, a risk assessment unit 102, an output display unit 103, a maintenance policy determination unit 104, and a measurement point setting unit 105. The mixed gas grid maintenance system 100 also includes a grid system information acquisition unit 111 and a grid operation information acquisition unit 112, and information acquired by each unit is supplied to the fluid analysis unit 101. Only one of the maintenance policy determination unit 104 and the measurement point setting unit 105 may be provided.

[0017] The fluid analysis unit 101 performs a fluid analysis process to calculate a distribution including a predetermined component concentration in the system. The risk assessment unit 102 extracts, as high-risk areas, locations where the hydrogen concentration is at least high from the distribution obtained by the fluid analysis unit 101. The specific details of the process for extracting high-risk areas from the results of fluid analysis processing will be described later. The output display unit 103 displays the risk assessment results, etc. obtained by the risk assessment unit 102. Alternatively, the output display unit 103 may output the risk assessment results, etc. to an external terminal and display them on the external terminal. The output display unit 103 may also display or output the results of the maintenance policy determination unit 104 or the measurement point setting unit 105.

[0018] The maintenance policy determination unit 104 determines a maintenance policy based on the risk assessment result from the risk assessment unit 102 . Based on the risk assessment results from the risk assessment unit 102, the measurement point setting unit 105 determines measurement points on the pipeline 1 of the mixed gas grid 4 that should be maintained and a maintenance policy for those measurement points.

[0019] The grid system information acquisition unit 111 performs a grid system information acquisition process to acquire grid system information 202. The acquired grid system information 202 is supplied to the fluid analysis unit 101. The grid operation information acquisition unit 112 performs a grid operation information acquisition process to acquire mixed gas grid operation information 203. The acquired grid operation information 203 is supplied to the fluid analysis unit 101.

[0020] [Example of hardware configuration for mixed gas grid maintenance system] The mixed gas grid maintenance system 100 shown in FIG. 1 can be configured by, for example, a computer. FIG. 2 shows an example of the configuration of a computer as the mixed gas grid maintenance system 100. As shown in FIG. 2, the mixed gas grid maintenance system 100, which is configured by a computer, includes a CPU (Central Processing Unit) 100a, a memory 100b, a storage 100c, an input unit 100d, a communication interface (I / F) 100e, and an output unit 100f.

[0021] The CPU 100a executes a program stored in the memory 100b or the storage 100c. The memory 100b is configured as, for example, a RAM (Random Access Memory), and stores computer programs and calculation result data, while providing the CPU 100a with a work area necessary for each process. When the CPU 100a executes the program, the work area in the memory 100b is configured with a fluid analysis unit 101, a risk assessment unit 102, a maintenance policy determination unit 104, a measurement point setting unit 105, and the like, as shown in FIG.

[0022] The storage 100c is configured with a hard disk drive (HDD) or a solid state drive (SSD), and stores computer programs as well as data required for calculations and calculation result data. For example, the storage 100c stores grid system information 202 and grid operation information 203. The storage 100c also stores calculation results such as risk assessment results.

[0023] The input unit 100d performs input processing such as input operation information from the operator. The communication interface 100e communicates with an external server, etc. For example, the communication interface 100e communicates with a measurement information server 210 that accumulates measurement data of the mixed gas grid 4, etc., to acquire measurement data of each point on the mixed gas grid 4, etc. A display serving as the output display unit 103 is connected to the output unit 100f, and information for displaying the risk assessment results, maintenance policy, measurement point setting information, and the like is supplied to the output display unit 103.

[0024] [Risk Assessment Processing] Next, a process flow for risk assessment in the mixed gas grid maintenance system 100 shown in FIG. 1 will be described. First, the fluid analysis unit 101 acquires the gas concentration distribution of the target gas grid. The gas concentration distribution is obtained from the fluid analysis results obtained by inputting grid system information 202 and grid operation information 203 into the fluid analysis unit 101. Here, the grid system information 202 is information about the shape and specifications of the gas grid, including gas grid pipeline route information, connection point information, pipeline diameter, pipeline length, etc.

[0025] In addition to the above information, if available, information such as the surface roughness and height position of the pipeline may also be included. Grid operation information includes the gas flow rate and pressure at gas usage points connected to the target gas grid, and the gas component concentration, flow rate and pressure at gas supply points. In addition to the above information, the calorific value, density and Wobbe index of the gas may also be included.

[0026] The fluid analysis unit 101 calculates, by simulation, the hydrogen gas concentration distribution 205, flow velocity distribution 206, and pressure distribution 207 of each pipeline in the grid based on grid system information 202 and grid operation information 203. The time-series information obtained as the grid operation information 203 includes the hydrogen gas concentration distribution, flow velocity distribution, pressure distribution, etc. The gas concentration distribution in the grid changes over time, so it is calculated and stored as time-series information.

[0027] The simulation in the fluid analysis unit 101 may use fluid analysis, machine learning, or optimization technology. In this embodiment, the fluid analysis unit 101 calculates the hydrogen gas concentration distribution, flow velocity distribution, and pressure distribution, but if measurement using a two-dimensional software sensor using an image is possible over a wide area, or if direct measurement is possible, measured values ​​may be used. Furthermore, it is preferable to obtain information about each pipeline as information for each grid, which is obtained by dividing the pipeline into specified sections.

[0028] Next, a process of risk assessment performed by the risk assessment unit 102 based on the information obtained by the fluid analysis unit 101 will be described. FIG. 3 is a flowchart showing an example of a process performed by the risk assessment unit 102 to assess a risk. First, the risk assessment unit 102 acquires the fluid analysis results obtained by the fluid analysis unit 101 (step S11). That is, the risk assessment unit 102 acquires the hydrogen gas concentration distribution 205, flow velocity distribution 206, and pressure distribution 207, which are the fluid analysis results obtained by the fluid analysis unit 101. In addition, the risk assessment unit 102 acquires criteria for performing risk assessment (step S12).

[0029] Then, the risk assessment unit 102 performs risk assessment calculations on these input values ​​to calculate the risk assessment result 208 (FIG. 1). The risk assessment calculation is performed for each pipeline grid based on a correspondence table that associates risk assessment values ​​with value ranges of gas hydrogen concentration. That is, the target gas grid includes n pipelines P1 to Pn, and each pipeline is divided into m1 to mn grids. Here, the risk assessment unit 102 selects a pipeline Pi (i is any value from 1 to n) to be calculated (step S13). Furthermore, the risk assessment unit 102 selects a pipeline grid mj (mj is any value from m1 to mn) (step S14).

[0030] The risk assessment unit 102 then compares the risk assessment value of the selected pipeline and grid with a preset threshold value for determining high risk to determine whether or not the risk is high (step S15). If the risk is high in step S15 (YES in step S15), the risk assessment unit 102 assigns a "high" risk value to the pipeline and grid (step S16).

[0031] If the pipeline and grid are not deemed high risk in step S15 (NO in step S15), the risk assessment unit 102 compares the risk assessment value of the selected pipeline and grid with a preset threshold value for determining medium risk to determine whether they are deemed medium risk (step S17). If the pipeline and grid are deemed medium risk in step S17 (YES in step S17), the risk assessment unit 102 assigns a value of "medium" risk to the pipeline and grid (step S18). If the pipeline and grid are not considered to be at risk in step S17 (NO in step S17), the risk assessment unit 102 assigns a "low" risk value to the pipeline and grid (step S19).

[0032] Here, specific examples of "high", "medium" and "low" risks will be explained. Because hydrogen gas leaks more easily than methane gas, the risk of gas leakage increases as the hydrogen gas concentration increases. For example, a gaseous hydrogen concentration of 3 vol% or less is defined as a "low risk," a gaseous hydrogen concentration of more than 3 vol% but less than 20 vol% is defined as a "medium risk," and a gaseous hydrogen concentration of more than 20 vol% is defined as a "high risk." Therefore, for example, the risk of a lattice having a hydrogen concentration of 3 vol % or less in the hydrogen gas concentration distribution 205 is low. If there is a grid that is judged to be a "high" or "medium" risk in step S16 or step S18, processing based on the risk value of each grid is performed by the maintenance policy determination unit 104 or the measurement point setting unit 105.

[0033] After the risk values ​​are assigned in steps S16, S18, and S19, the risk assessment unit 102 determines whether or not there are any lattices whose risk has not been determined (step S20). If there are any lattices whose risk has not been determined in step S20 (YES in step S20), the risk assessment unit 102 returns to the processing of step S14, selects another lattice whose risk has not been determined, and repeats the determination processing from step S15.

[0034] If there are no lattices whose risk has not been determined in step S20 (NO in step S20), the risk assessment unit 102 determines whether there are any pipelines whose risk has not been determined (step S21). If there are any pipelines whose risk has not been determined in step S21 (YES in step S21), the risk assessment unit 102 returns to the processing of step S13, selects another pipeline whose risk has not been determined, and repeats the determination processing from step S15. If there is no pipeline whose risk has not yet been determined in step S21 (NO in step S21), the risk assessment unit 102 ends the pipeline risk assessment process and obtains a risk assessment result 208.

[0035] In the processing example of the flowchart in Figure 3, the risk assessment is described as low, medium, and high, but assessing risk in three levels is just an example, and it may also be expressed using more levels or a determined numerical value. Furthermore, in the risk assessment calculation, a value obtained by performing further calculations based on the hydrogen gas concentration may be used as the criterion, or a criterion other than the hydrogen gas concentration may be added. For example, since a large amount of hydrogen gas filled in a pipeline increases the risk of leakage, the hydrogen gas filling may be calculated based on the results of fluid analysis and used as the criterion.

[0036] As criteria other than hydrogen gas concentration, for example, a high flow rate increases the risk of pipeline damage, so a high pressure increases the risk of pipeline leakage, so a high flow rate may be used as the criteria, so a high pressure may be used as the criteria.

[0037] Furthermore, these numerical values ​​do not need to monotonically increase or decrease relative to the risk; for example, it may be determined that the risk is high within a predetermined value range. For example, since vibration of a pipeline or connected equipment creates a risk of damage, if the gas density and flow rate are judged to meet the vibration conditions, the risk may be determined to be "high." Other values ​​that may be used as the criteria are the average value, maximum value, minimum value, range of change (maximum-minimum difference), deviation, and total value for any time or space unit.

[0038] The risk assessment result 208 thus obtained by the risk assessment unit 102 is supplied to the output display unit 103, where the risk assessment result 208 is displayed. Since the risk assessment result 208 is obtained as information for each pipeline grid, it is preferable to display it in different colors on the display screen, overlaid with a map or gas grid shape information. When the risk assessment result 208 is displayed, the judgment conditions for the risk assessment calculation may also be displayed, or a selection / input unit may be provided that allows the operator to change the conditions for the risk assessment calculation. An example of the display of the risk assessment result 208 will be described with reference to FIG. 4.

[0039] Next, the maintenance policy determination process in the maintenance policy determination unit 104 and the measurement point setting process in the measurement point setting unit 105 will be described. The risk assessment result 208 obtained by the risk assessment unit 102 is input to the maintenance policy determination unit 104 and the measurement point setting unit 105 . The maintenance policy determination unit 104 formulates a maintenance policy based on the risk assessment results 208. The maintenance policy involves determining whether condition monitoring is necessary, whether maintenance preparation is necessary, and the inspection frequency and inspection priority. Condition monitoring involves applying pressure and flow rate measurement technology and leak detection technology to high-risk pipeline locations so that maintenance can be carried out quickly in the event of a leak or damage. Maintenance preparation involves preparing replacement equipment, etc. for high-risk pipeline locations. The inspection frequency and inspection priority involve setting inspection priorities in order of increasing risk, and increasing the inspection frequency.

[0040] The measurement point setting unit 105 extracts candidate locations for installing measurement points based on the risk assessment result 208. The candidate locations for installing measurement points are locations that have been determined to be high risk in the risk assessment result 208. Furthermore, the measurement point setting unit 105 may work in conjunction with the maintenance policy determination unit 104 to set as candidates for installing measurement points grids of locations that require status monitoring or locations with high inspection priorities.

[0041] The information on the maintenance policy and measurement installation candidates output from the maintenance policy determination unit 104 and the measurement point setting unit 105 is supplied to the output display unit 103 and displayed together with the risk assessment results 208. Since the maintenance policy and measurement installation candidates are information linked to the pipeline grid, they may be displayed superimposed on a map, the shape of the gas grid, and the risk assessment results 208. For example, when displaying the maintenance policy, if "condition monitoring required" is selected using the radio button, the grid of pipelines requiring condition monitoring may be highlighted with a border or the like.

[0042] When displaying whether or not maintenance preparation is required in the maintenance policy, a list of the equipment required for the entire gas grid may be displayed. Also, an input unit may be provided that allows an operator to add a maintenance policy to any location displayed after viewing the risk assessment result 208. The measurement installation candidates may be displayed as markers on the gas grid. The number of measurement installation candidates across the entire gas grid and the costs associated with installing the measurement points may also be tallied and presented as a list. The measurement installation candidate list may be provided with an input unit that includes an editing function that allows an operator to add, change, or delete candidates at any location displayed based on the risk assessment results.

[0043] [Example of displaying risk assessment results, maintenance policy, and measurement installation candidates] FIG. 4 shows an example of display by the output display unit 103 of the risk assessment results, maintenance policy, and measurement installation candidate. The display screen shown in FIG. 4 has a map display area 311 of the mixed gas grid to be risk assessed, a maintenance policy state selection area 312, a measurement point candidate selection area 313, a risk assessment item area 314, and a maintenance policy area 315.

[0044] The map display area 311 graphically displays the configuration of the mixed gas grid to be evaluated. The example in Figure 4 shows the layout route of a pipeline 1, as well as multiple gas supply bases 2 and multiple gas usage bases 3 installed on the pipeline 1. The map display area 311 in Figure 4 also shows an overview of the facilities installed at each gas supply base 2 and gas usage base 3. For example, gas supply bases 2 include gas tanks and factories that produce hydrogen. Gas usage bases 3 include factories, buildings, and homes that use natural gas and hydrogen. In the example of FIG. 4, the map display area 311 displays a simple grid shape of the mixed gas grid, but a more detailed map may be displayed to show the pipeline 1 within the map.

[0045] 4, sections X1 and X2 that have been determined to be "high" risk in the risk assessment results by the risk assessment unit 102 are shown above the pipeline 1. Note that while only sections with "high" risk are shown here, for example, the three risk types of "high," "medium," and "low" in the risk assessment results may be shown on the pipeline 1 by color coding or the like. Furthermore, measurement points A, B, and C are shown on the pipeline 1 in the map display area 311 as candidates for measurement points that are preferably newly installed. These measurement points A, B, and C as measurement point candidates have been set by the measurement point setting unit 105 as points where maintenance is preferable based on the risk assessment results. Displaying the risk assessment results in different colors is just one example, and for example, a risk value may be displayed for each pipeline in the map display area 311. Alternatively, numerical values ​​of the analysis results, such as hydrogen concentration, may be displayed for each pipeline in the map display area 311. The risk values, hydrogen concentration, etc. may be displayed as a list.

[0046] The maintenance policy status selection area 312 displays whether the maintenance policy is status monitoring or maintenance preparation, and the operator can select either option. The measurement point candidate selection area 313 displays the priority of the measurement point candidates, and the operator can set the priority.

[0047] The risk assessment item area 314 shows details of the items for which the risk assessment unit 102 assesses risk. In the example of Fig. 4, the risk assessment item is hydrogen gas concentration, and lower and upper limit values ​​(vol%) for determining three risk categories of "high," "medium," and "low" are shown. In Fig. 4, 3 vol% and 20 vol% are set as threshold values.

[0048] The maintenance policy area 315 displays the priorities of measurement points A, B, and C, and the details of the maintenance of each of measurement points A, B, and C. For example, measurement point A is given priority 1, and the name (replacement valve) of the prepared item (replacement fixture) and details of its type are displayed. Furthermore, measurement point B is given priority 1, and the name (replacement pipe) of the prepared item (replacement fixture) and details of its type are displayed. Measurement point C is given priority 2. These maintenance details are determined based on the maintenance policy determined by the maintenance policy determination unit 104 and the setting of the measurement point by the measurement point setting unit 105.

[0049] As described above, the mixed gas grid maintenance system of this embodiment can improve the efficiency of inspection and maintenance and reduce the burden when operating a mixed gas grid for appropriately transporting hydrogen produced as clean energy. In other words, appropriate risk assessment can be performed for each pipeline and grid that make up the mixed gas grid, making it possible to appropriately perform maintenance of the mixed gas grid that transports hydrogen. Furthermore, as shown in Figure 4, by determining and displaying details such as replacement valves and pipes at each measurement point as a maintenance policy, inspection and maintenance can be carried out efficiently and appropriately.

[0050] [Variation 1 of risk assessment processing] FIG. 5 is a flowchart showing a first modification of the risk assessment process of the first embodiment. In the risk assessment process described in the flowchart of FIG. 3, the risk level is assessed in multiple stages according to the hydrogen gas concentration. However, in addition to obtaining risk assessment results based on the hydrogen gas concentration distribution described in Figure 3, other possible processes for obtaining risk assessment results include obtaining risk assessment results based on the hydrogen gas filling amount as a criterion, obtaining risk assessment results based on the range of fluctuations in flow rate over a predetermined time unit as a criterion, and obtaining risk assessment results based on two criteria, hydrogen gas concentration distribution and pressure distribution. First, as Variation 1, we will explain the case where risk assessment results are obtained based on the hydrogen gas filling amount as a criterion. The case where risk assessment results are obtained based on the range of fluctuations in flow rate over a predetermined time unit as a criterion will be described later as Variation 2.

[0051] Explaining according to the flowchart of FIG. 5, the risk assessment unit 102 receives the fluid analysis results from the fluid analysis unit 101 (step S31). The risk assessment unit 102 also acquires a judgment criterion (step S32). Here, the hydrogen gas concentration distribution is the hydrogen gas concentration value for each lattice of the pipeline included in the target gas grid. In this embodiment, the target gas grid includes n pipelines P1 to Pn, and each pipeline is divided into m1 to mn lattice sections for calculation. The total number of lattices for the pipelines included in the target gas grid is (m1 +... + mn). Note that the number of lattices for each pipeline does not need to be constant, and the number of divisions may be different for each pipeline.

[0052] Therefore, the risk assessment unit 102 selects a pipeline (step S33), and then selects a grid of the selected pipeline (step S34). The risk assessment unit 102 then calculates the hydrogen gas filling amount of the selected pipeline and grid (step S35) and selects one risk level, for example, from 1 to 5 (step S36). The risk assessment unit 102 then determines whether the hydrogen gas filling amount corresponds to the risk level value selected in step S36 (step S37). If the hydrogen gas filling amount does not correspond to the risk level value in step S37 (NO in step S37), the process returns to selecting another risk level value in step S36.

[0053] If the hydrogen gas filling amount corresponds to the value of the risk level in step S37 (YES in step S37), a risk level (risk value) is assigned to the corresponding pipeline and grid (step S38). After assigning the risk value in step S38, the risk assessment unit 102 determines whether there is a lattice whose risk has not been determined (step S39). If there is a lattice whose risk has not been determined in step S39 (YES in step S39), the risk assessment unit 102 returns to the processing of step S34, selects another lattice whose risk has not been determined, and repeats the determination processing.

[0054] If there are no lattices whose risk has not been determined in step S39 (NO in step S39), the risk assessment unit 102 determines whether there are any pipelines whose risk has not been determined (step S40). If there are any pipelines whose risk has not been determined in step S40 (YES in step S40), the risk assessment unit 102 returns to the processing of step S33, selects another pipeline whose risk has not been determined, and repeats the determination processing. If there is no pipeline whose risk has not yet been determined in step S40 (NO in step S40), the risk assessment unit 102 ends the pipeline risk assessment process and obtains a risk assessment result 208.

[0055] Here, a specific example of processing will be described in which the risk assessment result is set to levels 1 to 5 as the criterion obtained in step S32. The risk assessment unit 102 sets threshold values ​​for the hydrogen gas filling amount for each level based on the criteria obtained in step S32. For example, the lower limit threshold values ​​for the hydrogen gas filling amount for levels 1 to 5 are QL1, QL2, QL3, QL4, and QL5, and the upper limit threshold values ​​are QH1, QH2, QH3, QH4, and QH5. In other words, if the hydrogen gas filling amount is in the range of QL1 to QH1, it is determined to be level 1; if it is in the range of QL2 to QH2, it is determined to be level 2; and if it is in the range of QL5 to QH5, it is determined to be level 5. Note that QL1 may be 0, and QH5 may be infinity. Also, QH1 = QL2, QH2 = QL3, QH3 = QL4, and QH4 = QL5.

[0056] The hydrogen gas filling amount is calculated using the following formula [1].

[0057]

number

[0058] Here, Q H2 is the hydrogen gas filling amount (m 3 / s), C H2 is the hydrogen gas concentration in the mixed gas (vol%), Q gas is the flow rate of the mixed gas (m 3 / s). In step S36, for example, a level value is selected for the calculated hydrogen gas filling amount, starting with the highest level 5, and in step S37, a determination is made as to whether the threshold value of the selected level value corresponds to the risk level value. In step S37, if the threshold value of the selected level value corresponds to the risk level value, a process is performed to assign the selected level as a risk value. The risk assessment unit 102 performs this process in order, starting from level 5, until a risk level is assigned.

[0059] 5, five levels are set from 1 to 5, but there is no limit to the number or level names. The risk assessment unit 102 performs risk assessment for all grids ((m1+···+mn) grids) of a total of n pipelines, and outputs data with assigned risk values ​​as risk assessment results.

[0060] [Variation 2 of risk assessment process] FIG. 6 is a flowchart showing a second modification of the risk assessment process of the first embodiment. The risk assessment process of this modification 2 is a case where a risk assessment result is obtained based on the fluctuation range of the flow velocity in a predetermined time unit. Explaining this according to the flowchart in FIG. 6, the risk assessment unit 102 sets a time span and a time unit (step S41) and receives fluid analysis results from the fluid analysis unit 101 (step S42). Here, the time span is the time interval between data of the fluid analysis results and is set to, for example, 15 minutes. The time unit is the entire period over which the fluid analysis results are evaluated and is set to, for example, 24 hours. In this modification example 2, the risk assessment unit 102 acquires a total of 96 sets of time data as fluid analysis results, which are data for 24 hours at 15-minute intervals.

[0061] Next, the risk assessment unit 102 calculates the reference flow velocity fluctuation range (maximum-minimum difference) for each pipeline grid based on the flow velocity value from the acquired fluid analysis results (step S43). Subsequently, similar to the case of obtaining risk assessment results based on the hydrogen gas concentration distribution, the risk assessment unit 102 acquires a judgment criterion (step S44).

[0062] Here, the risk assessment unit 102 sets thresholds for classifying the risk assessment result as "low," "medium," or "high." The thresholds are set in the same time unit and time span as the reference value. For example, if the specified time unit is 24 hours, the thresholds are set assuming fluctuations over 24 hours. If the time span of the fluid analysis is 15 minutes, the thresholds are set assuming fluctuations over 15 minutes. For example, a "low" risk is set as a flow velocity fluctuation span of V1 m / s or less, a "medium" risk is set as V1 to V2 m / s, and a "high" risk is set as above V2 m / s.

[0063] Then, the risk assessment unit 102 selects a pipeline (step S45) and a grid (step S46). For the grid of the selected pipeline, the risk assessment unit 102 selects one of the risk levels for the fluctuation range of the flow rate: "high," "medium," or "low" (step S47), and determines whether the flow rate corresponds to the selected risk level (step S48). In step S48, if the flow velocity does not correspond to the selected risk level (NO in step S48), the process returns to step S47 to select another risk level.

[0064] If the flow velocity corresponds to the selected risk level in step S48, the risk assessment unit 102 assigns the determined risk value to the grid of the pipeline being assessed (step S49). The risk assessment unit 102 performs this process for all grids of a total of n pipelines ((m1 +... +mn) grids). That is, after assigning risk values ​​in step S49, the risk assessment unit 102 determines whether there are any grids whose risk has not been assessed (step S50). If there are any grids whose risk has not been assessed in step S50 (YES in step S50), the risk assessment unit 102 returns to the process of step S46, selects another grid whose risk has not been assessed, and repeats the assessment process.

[0065] If there are no lattices whose risk has not been determined in step S50 (NO in step S50), the risk assessment unit 102 determines whether there are any pipelines whose risk has not been determined (step S51). If there are any pipelines whose risk has not been determined in step S51 (YES in step S51), the risk assessment unit 102 returns to the processing of step S45, selects another pipeline whose risk has not been determined, and repeats the determination processing. If there is no pipeline whose risk has not yet been determined in step S51 (NO in step S51), the risk assessment unit 102 ends the pipeline risk assessment process and obtains a risk assessment result 208.

[0066] [Variation 3 of risk assessment process] FIG. 7 is a flowchart showing a third modification of the risk assessment process of the first embodiment. The risk assessment process of this modification 3 is a case where a risk assessment result is obtained based on two criteria: the hydrogen gas concentration and pressure. Explaining this according to the flowchart in Fig. 7, the risk assessment unit 102 performs risk assessment for the hydrogen gas concentration and pressure by threshold judgment, similar to the case of obtaining a risk assessment result based on the hydrogen gas concentration distribution described in Fig. 3. That is, the risk assessment unit 102 selects criteria for performing risk assessment (step S61). Here, two criteria are selected. Here, two types of criteria are used for risk assessment, but if there are three or more types of criteria for risk assessment, three or more types of criteria are selected. Then, the risk assessment unit 102 obtains a risk assessment result for each risk assessment criterion (step S62).

[0067] Next, the risk assessment unit 102 selects a pipeline (step S63) and a grid (step S64), and acquires a risk assessment result based on the hydrogen gas concentration distribution and a risk assessment result based on the pressure for the grid of the selected pipeline. Furthermore, the risk assessment unit 102 calculates a comprehensive risk result from the risk assessment result based on the hydrogen gas concentration distribution and the risk assessment result based on the pressure (step S65), and assigns the calculated risk level (step S66).

[0068] Here, the overall risk result is calculated from two or more types of risk assessment results, and the risk assessment unit 102 may, for example, use the higher risk value from the individual risk assessment results, use the sum or average of the individual risk values, or assign weights to the individual risk assessment results and use a weighted average value, etc. The calculation method for the overall risk result may be set by the operator based on their knowledge, or may be defined in advance together with the combination of two or more types of risk assessment results.

[0069] The assignment of risk levels in step S66 is performed for all lattices ((m1+···+mn) lattices) in a total of n pipelines. That is, after assigning risk values ​​in step S66, the risk assessment unit 102 determines whether or not there are any lattices whose risk has not been determined (step S67). If there are any lattices whose risk has not been determined in step S67 (YES in step S67), the risk assessment unit 102 returns to the processing of step S64, selects another lattice whose risk has not been determined, and repeats the determination processing.

[0070] If there are no lattices whose risk has not been determined in step S67 (NO in step S67), the risk assessment unit 102 determines whether there are any pipelines whose risk has not been determined (step S68). If there are any pipelines whose risk has not been determined in step S68 (YES in step S68), the risk assessment unit 102 returns to the processing of step S63, selects another pipeline whose risk has not been determined, and repeats the determination processing. If there is no pipeline whose risk has not yet been determined in step S68 (NO in step S68), the risk assessment unit 102 ends the pipeline risk assessment process and obtains a risk assessment result 208.

[0071] <Second embodiment> Next, a mixed gas grid maintenance system and a mixed gas grid maintenance method according to a second embodiment of the present invention will be described with reference to Figures 8 and 9. In Figures 8 and 9, parts corresponding to those in Figures 1 to 7 described in the first embodiment are given the same reference numerals, and duplicated explanations will be omitted.

[0072] [Configuration of mixed gas grid maintenance system] In this embodiment, the mixed gas grid maintenance system described in the first embodiment is utilized to perform more effective inspections. Fig. 8 shows a configuration example of the mixed gas grid maintenance system 100 according to this embodiment. The mixed gas grid maintenance system 100 shown in Fig. 8 includes an inspection time setting unit 106 in addition to the configuration of the mixed gas grid maintenance system 100 shown in Fig. 1.

[0073] Here, the fluid analysis unit 101 acquires the fluid analysis results for a predetermined time width and for each time unit. The fluid analysis results calculated by the fluid analysis unit 101 for a predetermined time span and time unit, namely, a hydrogen gas concentration distribution 205, a flow velocity distribution 206, and a pressure distribution 207, are input to the risk assessment unit 102. The risk assessment unit 102 obtains risk assessment results 208 for the predetermined time span and time unit. For example, the risk assessment unit 102 obtains fluid analysis results and risk assessment results for a total of 96 sets of time data, which are data for 24 hours at 15-minute intervals. The inspection time setting unit 106 extracts an appropriate time period for inspection from the time data of the risk assessment result. The appropriate time period for inspection is the time period with the highest risk when comparing the fluctuation of the risk value with respect to time.

[0074] If there are multiple time periods where the risk is high, multiple candidates may be extracted along with the risk value. Because gas usage patterns vary depending on the day of the week or the day of the week, the time unit should be a range that allows for the trend of changes in usage patterns to be obtained. Furthermore, when hydrogen gas is produced by electrolysis using electricity derived from renewable energy sources or surplus electricity, it is affected by the season, weather, hours of sunlight, and wind speed. Therefore, risk may be evaluated based on these values, and an inspection schedule may be set. If a large amount of time data can be obtained, a more appropriate inspection time period may be extracted by comparing it with the average value for days or days of the week over a long period.

[0075] Furthermore, when extracting these inspection time periods, the risk values ​​(or average risk values) for the time periods and the cycles related to the time periods may be displayed. At this time, a graph visualization and analysis tool may be provided to allow the operator to change the time period or cycle selection and select a more appropriate time period. By performing inspections during high-risk time periods, abnormalities can be detected more clearly than during low-risk time periods.

[0076] [Example of display of possible inspection times, etc.] FIG. 9 shows an example of a display by the output display unit 103 in this embodiment. 9 has a map display area 311 of the mixed gas grid that is the target of risk assessment, a maintenance policy state selection area 312, and a measurement point candidate selection area 313, similar to the display screen shown in FIG. The display screen shown in FIG. 9 further includes an inspection candidate selection area 316, an inspection candidate time display area 317, and a risk assessment display area 318.

[0077] In the inspection candidate selection area 316, the operator can set weekdays, Saturdays, and Sundays as the days of the week to be included in the inspection candidates. In the proposed inspection time display area 317, a list of proposed inspection times for measurement points A, B, and C is displayed. That is, the inspection candidate time display area 317 displays a list of the inspection candidate dates and times, the estimated hydrogen concentrations, and the estimated risk values.

[0078] The risk assessment display area 318 displays a graph of the time-varying risk level characteristics of measurement points A, B, and C, which are measurement points with high risk levels, and the recommended inspection time periods for each. That is, in the risk assessment display area 318, the time period with the highest risk level for each of measurement points A, B, and C is displayed as the recommended inspection time period. The risk assessment display area 318 also displays the period for which the graph is displayed.

[0079] As described above, the mixed gas grid maintenance system of this embodiment has the effect of making it possible to issue instructions to carry out inspections during times when risks are higher, making it easier to detect risks.

[0080] <Third embodiment> Next, a mixed gas grid maintenance system and a mixed gas grid maintenance method according to a third embodiment of the present invention will be described with reference to Figures 10 and 11. In Figures 10 and 11, parts corresponding to those in Figures 1 to 7 described in the first embodiment are given the same reference numerals, and duplicated explanations will be omitted.

[0081] [Configuration of mixed gas grid maintenance system] In this embodiment, the mixed gas grid maintenance system explained in the first embodiment further includes an abnormality detection unit. FIG. 10 shows the configuration of a mixed gas grid maintenance system 100 according to this embodiment. The mixed gas grid maintenance system 100 includes an abnormality detection unit 120. The abnormality detection unit 120 includes an abnormality detection fluid analysis unit 121 and an output display unit 122. The output display unit 122 may also serve as the output display unit 103.

[0082] The abnormality detection unit 120 acquires measurement point position information 211 and grid system information 213 from the grid system information acquisition unit 111. In addition, the abnormality detection unit 120 acquires grid operation information 212 from the grid operation information acquisition unit 112. In addition, the abnormality detection unit 120 continuously acquires measurement data at measurement points that are actually installed at the measurement point installation positions obtained in the mixed gas grid maintenance system 100.

[0083] Grid system information 213 and continuously acquired grid operation information 212 are input to an anomaly detection fluid analysis unit 121 of the anomaly detection unit 120. Then, the anomaly detection fluid analysis unit 121 calculates gas information such as hydrogen gas concentration, density, and calorific value at each measurement point, and fluid information such as pressure, flow velocity, and flow rate. Furthermore, the anomaly detection fluid analysis unit 121 compares the values ​​of these gas information and fluid information with the measurement data at the measurement point and calculates the difference. Note that the measurement target of the equipment installed at the measurement point includes at least one of the items included in the gas information and fluid information that can be calculated by fluid analysis.

[0084] If the calculated difference exceeds a predetermined threshold, the anomaly detection fluid analysis unit 121 detects it as an anomaly and obtains anomaly detection information 221. If an anomaly is detected by the anomaly detection information 221, the output display unit 122 displays the occurrence of the anomaly and the location of the measurement point where the anomaly occurred on its screen. At this time, it is preferable that the output display unit 122 also displays the measurement data, gas information calculated by the fluid analysis, fluid information, and difference value. Furthermore, the output display unit 122 may be linked to the risk assessment unit 102, maintenance policy determination unit 104, and measurement point setting unit 105 of the mixed gas grid maintenance system 100 to display information about the entire target gas grid and historical operating data.

[0085] [Example of display of possible inspection times, etc.] FIG. 11 shows an example of a display by the output display unit 122 in this embodiment. The display screen shown in FIG. 11, like the display screen shown in FIG. 4, has a map display area 311 of the mixed gas grid that is the target of risk assessment, a maintenance policy state selection area 312, and a measurement point candidate selection area 313. The display screen shown in FIG. 11 further includes an abnormality detection information display area 319.

[0086] The anomaly detection information display area 319 displays the hydrogen concentration for each day of the week (weekday, holiday) at measurement points A, B, and C where the anomaly occurred. Fig. 11 shows an example in which the hydrogen concentration is displayed, but it is also possible to switch to other items.

[0087] As described above, the mixed gas grid maintenance system and mixed gas grid maintenance method of this embodiment make it possible to detect abnormalities using data from measurement points installed in high-risk locations.

[0088] <Modification> It should be noted that the embodiments described so far have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. For example, while the above-described embodiments are applied to a mixed grid that transports a mixed gas of natural gas and hydrogen, the present invention may also be applied to a mixed grid that transports carbon dioxide gas in addition to natural gas and hydrogen.Furthermore, the present invention can also be applied to a mixed grid that transports a mixed gas of hydrogen and carbon dioxide gas, or a mixed grid that transports a mixed gas of natural gas and carbon dioxide gas.

[0089] In addition, the configuration diagrams shown in Figures 1, 2, 8, and 10 only show control lines and information lines that are considered necessary for explanation, and do not necessarily show all control lines and information lines in the product. In reality, it can be assumed that almost all components are interconnected. In addition, the flowcharts shown in Figures 3, 5, 6, and 7 are also examples, and the order of some of the processes may be changed or multiple processes may be executed simultaneously as long as the processing results are the same. The display examples shown in Figures 4, 9, and 10 are also only examples, and other display forms that can notify similar content may be used.

[0090] The mixed gas grid maintenance system 100 described in each of the above-described embodiments may be configured by implementing a program that executes the processes shown in the flowcharts of Fig. 3, 5, 6, or 7, and in this case, the program is prepared in memory or storage within the computer shown in Fig. 2. Alternatively, the program executed by the computer serving as the mixed gas grid maintenance system 100 may be stored in a recording medium such as an external memory, IC card, SD card, or optical disk, and transferred to the computer that functions as the mixed gas grid maintenance system 100.

[0091] 1, 8, and 10 show an example in which the mixed gas grid maintenance system 100 is configured as one device (computer). However, each of the units, such as the information acquisition unit, fluid analysis unit, and risk assessment unit, may be configured as a server connected to a network, and terminals serving as output display units connected to these servers may display the evaluation results, etc. [Explanation of symbols]

[0092] 100...grid maintenance planning system, 100a...CPU, 100b...memory, 100c...storage, 100d...input unit, 100e...communication interface, 100f...output unit, 101...fluid analysis unit, 102...risk assessment unit, 103...output display unit, 104...maintenance policy determination unit, 105...measurement point setting unit, 106...inspection time setting unit, 110...maintenance planning system, 111...grid system information acquisition unit, 112...grid operation information acquisition unit, 120...abnormality detection unit, 121...abnormality detection fluid analysis unit, 122...output display unit, 202...grid system information, 203...grid operation information, 205...hydrogen gas concentration distribution, 206...flow velocity distribution, 207...pressure distribution, 208...risk assessment result, 210...measurement information server, 211... Measuring point position information, 212... Grid operation information, 213... Grid system information, 221... Abnormality detection information, 311... Map display area, 312... Status selection area, 313... Measuring point candidate selection area, 314... Risk evaluation item area, 315... Maintenance policy area

Claims

1. A mixed gas grid maintenance system that determines a maintenance policy for a gas grid that is configured by a mixed gas pipeline that transports a mixed gas containing hydrogen, a grid system information acquisition unit that acquires system information of the mixed gas pipeline; a grid operation information acquisition unit that acquires operation information of the mixed gas pipeline; a fluid analysis unit that calculates a hydrogen concentration distribution in each system of the gas grid by fluid analysis using as input the system information acquired by the grid system information acquisition unit and the operation information acquired by the grid operation information acquisition unit; a risk assessment unit that extracts locations with high hydrogen concentrations as high-risk areas based on the hydrogen concentration distribution calculated by the fluid analysis unit; an output unit that outputs or displays the risk assessment result obtained by the risk assessment unit; Mixed gas grid maintenance system.

2. the fluid analysis unit calculates the amount of hydrogen filled in each system of the gas grid based on the concentration, pressure, and flow rate of hydrogen in the gas; The risk assessment unit assesses risk based on spatial distribution within the piping. The mixed gas grid maintenance system of claim 1 .

3. The risk assessment unit assesses risk based on the maximum, minimum and fluctuation range of the spatial distribution and time fluctuation of the concentration, pressure and flow rate of hydrogen in the mixed gas within the pipe. The mixed gas grid maintenance system of claim 1 .

4. an inspection time setting unit that extracts candidates for inspection time periods from risk values ​​obtained based on the spatial distribution and time fluctuations of the concentration, pressure, and flow velocity calculated by the risk assessment unit; The output unit outputs or displays the candidates for the inspection time period extracted by the inspection time setting unit. The mixed gas grid maintenance system of claim 1 .

5. the output unit outputs or displays a risk value or an average risk value for the candidate time period extracted by the inspection time setting unit or a period related to the time period; Further, an input unit for selecting the time period or the period is provided. The mixed gas grid maintenance system of claim 4.

6. and an anomaly detection unit that detects anomalies by comparing measurement data from measurement points installed in a grid formed by the mixed gas pipeline with the fluid analysis results from the fluid analysis unit. The mixed gas grid maintenance system of claim 1 .

7. The output unit outputs or displays the risk assessment result by the risk assessment unit and candidates for equipment to be maintained as a maintenance policy based on the risk assessment result. The mixed gas grid maintenance system of claim 1 .

8. The output unit outputs or displays a display showing the grid shape of the gas grid and the hydrogen concentration at the measurement point in the display showing the grid shape. The mixed gas grid maintenance system of claim 1 .

9. The output unit displays whether or not the abnormality has been detected by the abnormality detection unit and the position of the measurement point where the abnormality has been detected. The mixed gas grid maintenance system of claim 6.

10. A mixed gas grid maintenance method for determining a maintenance policy for a gas grid configured by a mixed gas pipeline that transports a mixed gas containing hydrogen, comprising: a grid system information acquisition process for acquiring system information of the mixed gas pipeline; a grid operation information acquisition process for acquiring operation information of the mixed gas pipeline; a fluid analysis process that calculates a hydrogen concentration distribution in each system of the gas grid by fluid analysis using, as input, system information acquired by the grid system information acquisition process and operation information acquired by the grid operation information acquisition process; a risk assessment process for extracting locations with high hydrogen concentrations as high-risk areas based on the hydrogen concentration distribution calculated by the fluid analysis process; and an output process for outputting or displaying the risk assessment results obtained by the risk assessment process. Mixed gas grid maintenance methods.

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