Estimation device, estimation method, and estimation program

Abstract

This estimation device (10) acquires the density of the gas measured by a gas density meter (30), and estimates the state of the gas on the basis of the acquired gas density and a non-linear relational expression.

Description

Estimation device, estimation method, and estimation program

[0001] The present invention relates to an estimation device, an estimation method, and an estimation program.

[0002] Chemical substances in chemical processes are analyzed using measurement methods appropriate for each chemical substance. For example, carbon dioxide and methane are analyzed using infrared gas analyzers, laser gas analyzers, gas chromatography, etc. Hydrogen is analyzed using thermal conductivity meters, gas chromatography, etc.

[0003] Japanese Patent Application Laid-Open No. 2019-142807

[0004] However, it is difficult to easily monitor the state of gases in chemical processes. For example, conventional techniques require pretreatment for chemical analysis of each gas component, and in principle, some techniques have a long response time.

[0005] The present invention has been made in view of the above, and has as its object to easily monitor the state of gas in a chemical process.

[0006] An estimation device according to one embodiment of the present invention includes an acquisition unit that acquires the density of a gas measured by a gas density meter, and an estimation unit that estimates the state of the gas based on the acquired density and a nonlinear relational equation.

[0007] In an estimation method according to one embodiment of the present invention, a computer executes a process of acquiring the density of a gas measured by a gas density meter and estimating the state of the gas based on the acquired density and a nonlinear relational equation.

[0008] An estimation program according to one embodiment of the present invention causes a computer to execute a process of acquiring the density of a gas measured by a gas density meter and estimating the state of the gas based on the acquired density and a nonlinear relational equation.

[0009] According to the present invention, it is possible to easily monitor the state of gas in a chemical process.

[0010] 1 is a diagram illustrating an example of the configuration and processing of a gas monitoring system according to an embodiment. FIG. 2 is a block diagram illustrating an example of the configuration of each device of a gas monitoring system according to an embodiment. FIG. 3 is a diagram illustrating an example of an estimation result storage unit of an estimation device according to an embodiment. FIG. 4 is a diagram illustrating an example of a prediction model storage unit of an estimation device according to an embodiment. FIG. 5 is a diagram illustrating a specific example 1 of an estimation formula in an embodiment. FIG. 6 is a diagram illustrating a specific example 2 of an estimation formula in an embodiment. FIG. 7 is a diagram illustrating a specific example 3 of an estimation formula in an embodiment. FIG. 8 is a diagram illustrating a specific example 4 of an estimation formula in an embodiment. FIG. 9 is a diagram illustrating a specific example of a time series change in methane according to an embodiment. A flowchart illustrating an example of the overall flow of a gas monitoring system according to an embodiment. A flowchart illustrating an example of the flow of an acquisition control process of a gas monitoring system according to an embodiment. A flowchart illustrating an example of the flow of an estimation control process of a gas monitoring system according to an embodiment. A flowchart illustrating an example of the flow of a notification control process of a gas monitoring system according to an embodiment. FIG. 10 is a diagram illustrating an example of the hardware configuration according to an embodiment.

[0011] An estimation device, an estimation method, and an estimation program according to an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0012] The following describes the configuration and processing of the gas monitoring system 100 according to the embodiment, the configuration and processing of each device in the gas monitoring system 100, the processing flow of the gas monitoring system 100, the effects of the embodiment, and application examples of the embodiment.

[0013] 1. Configuration and Processing of Gas Monitoring System 100 The configuration and processing of the gas monitoring system 100 according to an embodiment will be described using Fig. 1. Fig. 1 is a diagram showing an example configuration and processing of the gas monitoring system 100 according to an embodiment. Below, an example configuration of a methanation reaction chemical process, an example configuration of the entire gas monitoring system 100, an example processing of the gas monitoring system 100, and the effects of the gas monitoring system 100 will be described.

[0014] In the embodiment, a methanation reaction for producing methane M from carbon dioxide C and hydrogen H will be described as an example, but the type of gas produced and the type of reaction are not particularly limited.

[0015] (1-1. Example of the configuration of a chemical process of a methanation reaction) An example of the configuration of a chemical process of a methanation reaction will be described below. In the following, exhaust gas recovery, carbon dioxide separation and recovery, carbon dioxide compression, carbon dioxide storage, hydrogen production, and a methanation reaction will be described.

[0016] (1-1-1. Exhaust Gas Recovery) As shown in FIG. 1(A), in the chemical process of methanation reaction, exhaust gas recovery is a process of recovering exhaust gas generated by combustion of fossil fuels or the like in a boiler or the like.

[0017] (1-1-2. Carbon Dioxide Separation and Capture) As shown in FIG. 1(B), in the chemical process of the methanation reaction, carbon dioxide separation and capture is a process of separating and capturing carbon dioxide C from the captured flue gas.

[0018] (1-1-3. Carbon Dioxide Compression) As shown in FIG. 1(C), in the chemical process of the methanation reaction, carbon dioxide compression is a process of compressing the recovered carbon dioxide C.

[0019] (1-1-4. Carbon Dioxide Storage) As shown in FIG. 1(D), in the chemical process of the methanation reaction, carbon dioxide storage is a process of storing compressed carbon dioxide C.

[0020] (1-1-5. Hydrogen Production) As shown in FIG. 1(E), in the chemical process of methanation reaction, hydrogen production is a process of producing hydrogen H by electrolysis of water or the like.

[0021] (1-1-6. Methanation Reaction) As shown in FIG. 1(F), in the chemical process of methanation reaction, carbon dioxide C and hydrogen H as reactants are reacted to produce methane M as a product. In this methanation reaction, a chemical reaction shown in the following chemical reaction formula (1) proceeds by adding a predetermined catalyst and maintaining a predetermined pressure and temperature. In the following formula (1), "CO ２ " is carbon dioxide C, "H ２ " is hydrogen H, "CH ４ " is methane M, "H ２ O" is water. Also, under normal temperature and pressure conditions, carbon dioxide C, hydrogen H, and methane M are gases, and water is a liquid.

[0022] CO ２ +4H ２ →CH ４ +2H ２ O (1)

[0023] (1-2. Example of the Overall Configuration of the Gas Monitoring System 100) An example of the overall configuration of the gas monitoring system 100 will be described. The gas monitoring system 100 has an estimation device 10, an operator terminal 20, and a gas density meter 30. Here, the estimation device 10, the operator terminal 20, and the gas density meter 30 are connected to each other via a predetermined communication network (not shown) so that they can communicate with each other via wired or wireless communication. Note that the predetermined communication network can be any of various communication networks such as the Internet or a dedicated line.

[0024] (1-2-1. Estimation Device 10) The estimation device 10 is a device that estimates the state of each gas in the chemical process of a methanation reaction. Note that the gas monitoring system 100 shown in FIG. 1 may include multiple estimation devices 10.

[0025] (1-2-2. Operator Terminal 20) The operator terminal 20 is a manager terminal used by an operator O who is the manager of the chemical process to be monitored. Note that the gas monitoring system 100 shown in FIG. 1 may include multiple operator terminals 20.

[0026] (1-2-3. Gas Density Meter 30) The gas density meter 30 is a measuring instrument that measures the density of each gas in the methanation reaction chemical process. For example, the gas density meter 30 is a process-use vibration-type gas densitometer that uses the principle that the resonant frequency of a thin-walled cylinder changes depending on the gas density around the cylinder. The gas densitometer 30 can measure the density of all gases except corrosive gases. The gas densitometer 30 is applicable to many applications, such as oil refineries and steel plants, and can measure not only gas density but also physical quantities such as specific gravity, molecular weight, gas concentration, and calorific value that can be calculated from density. In this case, the gas densitometer 30 is installed so that it can measure each gas in the methanation reaction chemical process. Note that the gas monitoring system 100 shown in FIG. 1 may include multiple gas densitometers 30.

[0027] In a first installation example, one gas densitometer 30 is installed in a chemical process of a methanation reaction, and is installed so as to be able to measure the density of each gas in response to the switching of the flow paths by a flow path switching unit. That is, in the first installation example, the single gas densitometer 30 is installed at the branching point of the flow path through which carbon dioxide C passes before mixing (FIG. 1(2)), the flow path through which hydrogen H passes before mixing (FIG. 1(3)), the flow path through which a mixed gas of carbon dioxide C and hydrogen H passes before reaction (FIG. 1(4)), and the flow path through which a mixed gas of methane M, carbon dioxide C, and hydrogen H passes after reaction (FIG. 1(5)), and can measure the density of the gas passing through any flow path in response to the switching of the flow paths by the flow path switching unit.

[0028] In a second installation example, multiple gas densitometers 30 (30-1, 30-2, 30-3, 30-4) are installed in each flow path of the methanation reaction chemical process, respectively, and are installed so as to be able to measure the density of each gas in each process. That is, in the second installation example, gas densitometer 30-1 (not shown) is installed in the flow path through which carbon dioxide C passes before mixing, as shown in FIG. 1(2) to be described later, and can measure the density of carbon dioxide C before mixing. Furthermore, gas densitometer 30-2 (not shown) is installed in the flow path through which hydrogen H passes before mixing, as shown in FIG. 1(3), and can measure the density of hydrogen H before mixing. Furthermore, gas densitometer 30-3 (not shown) is installed in the flow path through which a mixed gas of carbon dioxide C and hydrogen H before reaction passes, as shown in FIG. 1(4), and can measure the density of the mixed gas of carbon dioxide C and hydrogen H before reaction. In addition, a gas density meter 30-4 (not shown) is installed in the flow path through which the mixed gas of methane M, carbon dioxide C, and hydrogen H after the reaction shown in FIG. 1(5) passes, and can measure the density of the mixed gas of methane M, carbon dioxide C, and hydrogen H after the reaction.

[0029] (1-3. Example of processing performed by the entire gas monitoring system 100) An example of processing performed by the entire gas monitoring system 100 will now be described. Note that the processing shown in (1) to (6) of FIG. 1 below can be executed in a different order. Furthermore, some of the processing shown in (1) to (6) of FIG. 1 below may be omitted.

[0030] (1-3-1. Gas Density Measurement Process) First, the gas densitometer 30 measures the density of each gas (see FIG. 1(1)). For example, the gas densitometer 30 measures the density of carbon dioxide C before mixing, which is one of the reactants of the methanation reaction. The gas densitometer 30 also measures the density of hydrogen H before mixing, which is one of the reactants of the methanation reaction. The gas densitometer 30 also measures the density of a mixed gas of carbon dioxide C and hydrogen H, which are reactants of the methanation reaction, before the methanation reaction. The gas densitometer 30 also measures the density of a mixed gas of methane M, which is a product of the methanation reaction, unreacted carbon dioxide C, and unreacted hydrogen H, after the methanation reaction and after dehumidification.

[0031] (1-3-2. Carbon Dioxide Purity Estimation Process) Second, the estimation device 10 estimates the purity of the carbon dioxide C before mixing (see FIG. 1(2)). For example, the estimation device 10 acquires the density of the carbon dioxide C before mixing from the gas density meter 30, and estimates the purity of the carbon dioxide C from the acquired density. At this time, the estimation device 10 estimates the purity of the carbon dioxide C using estimation formula E(1) which shows a linear relationship between the density of the gas and the purity of the carbon dioxide C.

[0032] (1-3-3. Hydrogen Purity Estimation Process) Third, the estimation device 10 estimates the purity of hydrogen H before mixing (see FIG. 1(3)). For example, the estimation device 10 acquires the density of hydrogen H before mixing from the gas density meter 30, and estimates the purity of hydrogen H from the acquired density. At this time, the estimation device 10 estimates the purity of hydrogen H using estimation formula E(2), which shows a linear relationship between the density of the gas and the purity of hydrogen H.

[0033] (1-3-4. Mixing Ratio Estimation Process) Fourth, the estimation device 10 estimates the mixing ratio of carbon dioxide C and hydrogen H before the reaction (see FIG. 1(4)). For example, the estimation device 10 acquires the density of the mixed gas of carbon dioxide C and hydrogen H before the reaction from the gas density meter 30, and estimates the mixing ratio of carbon dioxide C and hydrogen H from the acquired density. At this time, the estimation device 10 estimates the mixing ratio of carbon dioxide C and hydrogen H using estimation formula E(3), which indicates a nonlinear relational expression between the density and the mixing ratio of the gases.

[0034] (1-3-5. Reaction Rate Estimation Process) Fifth, the estimation device 10 estimates the reaction rate of methane M after the reaction (see FIG. 1 (5)). For example, the estimation device 10 acquires the density of a mixed gas of methane M, carbon dioxide C, and hydrogen H after the reaction from the gas density meter 30, and estimates the reaction rate of methane M from the acquired density. At this time, the estimation device 10 estimates the reaction rate of methane M using estimation formula E(4), which indicates a nonlinear relational expression between the density and the reaction rate of the gas.

[0035] (1-3-6. Estimation Result Notification Process) Sixth, the estimation device 10 notifies the operator O of the estimation result (see FIG. 1 (6)). For example, the estimation device 10 transmits the estimated purity of carbon dioxide C, purity of hydrogen H, mixing ratio of carbon dioxide C and hydrogen H, and reaction rate of methane M to the operator terminal 20 of the operator O, and displays them on the monitor of the operator terminal 20.

[0036] (1-3-7. Other) The estimation device 10 can also estimate the future state of each gas using a prediction model PM, which is a trained machine learning model. For example, the estimation device 10 can use the prediction model PM, which outputs the state of a gas in response to an input of the gas density, to estimate the purity of carbon dioxide C, the purity of hydrogen H, the mixing ratio of carbon dioxide C and hydrogen H, or the reaction rate of methane M after a predetermined period of time from each acquired density.

[0037] The estimation device 10 can also notify the operator O of an alarm. For example, if any of the estimated purity of carbon dioxide C, purity of hydrogen H, mixing ratio of carbon dioxide C and hydrogen H, or reaction rate of methane M is not within a predetermined range set in advance, the estimation device 10 can transmit an alarm to the operator terminal 20 of the operator O and display it on the monitor of the operator terminal 20. Furthermore, if any of the purity of carbon dioxide C, purity of hydrogen H, mixing ratio of carbon dioxide C and hydrogen H, or reaction rate of methane M after a predetermined period of time estimated using the prediction model PM is not within a predetermined range set in advance, the estimation device 10 can transmit an alarm to the operator terminal 20 of the operator O and display it on the monitor of the operator terminal 20.

[0038] The estimation device 10 can also correct the estimation formula based on the estimation results. For example, the estimation device 10 can correct the estimation formula E(3) that estimates the mixing ratio of carbon dioxide C and hydrogen H based on the estimated purity of carbon dioxide C and the estimated purity of hydrogen H. The estimation device 10 can also correct the estimation formula E(4) that estimates the reaction rate of methane M based on the estimated mixing ratio of carbon dioxide C and hydrogen H.

[0039] (1-4. Effects of Gas Monitoring System 100) Below, the problems with the gas monitoring system 100P according to the reference technology will be explained, followed by an explanation of the effects of the gas monitoring system 100.

[0040] (1-4-1. Problems of the Gas Monitoring System 100P) In the gas monitoring system 100P, a measurement method appropriate for each chemical substance is used to analyze the chemical substances in the methanation reaction chemical process. For example, carbon dioxide and methane are analyzed using an infrared gas analyzer, a laser gas analyzer, gas chromatography, etc. Hydrogen is analyzed using a thermal conductivity meter, gas chromatography, etc. However, the gas monitoring system 100P has the following problems. First, the gas monitoring system 100P has the problem that preprocessing is required to chemically analyze each gas component, and in principle, some systems have a long response time. Second, the gas monitoring system 100P has the problem that a large-scale and expensive measurement method is required to chemically analyze each gas component.

[0041] (1-4-2. Overview of Gas Monitoring System 100) The gas monitoring system 100 performs the following processes. First, the gas densitometer 30 measures the density of carbon dioxide C before mixing, the density of hydrogen H before mixing, the density of the mixed gas before the methanation reaction, and the density of the mixed gas after the methanation reaction and dehumidification. Second, the estimation device 10 acquires the density of carbon dioxide C before mixing measured by the gas densitometer 30 and estimates the purity of carbon dioxide C before mixing using a linear estimation formula E(1). Third, the estimation device 10 acquires the density of hydrogen H before mixing measured by the gas densitometer 30 and estimates the purity of hydrogen H before mixing using a linear estimation formula E(2). Fourth, the estimation device 10 acquires the density of the mixed gas before the methanation reaction measured by the gas densitometer 30 and estimates the mixing ratio of carbon dioxide C and hydrogen H before the reaction using a nonlinear estimation formula E(3). Fifth, the estimation device 10 obtains the density of the mixed gas after the methanation reaction and dehumidification measured by the gas density meter 30, and estimates the reaction rate of methane M using the nonlinear estimation formula E(4). Sixth, the estimation device 10 notifies the operator O of the estimated purity of carbon dioxide C, purity of hydrogen H, mixing ratio of carbon dioxide C and hydrogen H, and reaction rate of methane M as estimation results.

[0042] (1-4-3. Effects of the Gas Monitoring System 100) The gas monitoring system 100 has the following effects. First, the gas monitoring system 100 can easily estimate the gas state, such as reaction and purity, using gas density as an index in a methanation reaction, rather than directly measuring each gas component. Second, the gas monitoring system 100 can inexpensively estimate the gas state in a methanation reaction. Third, the gas monitoring system 100 can accurately estimate the gas state in a methanation reaction because the raw material components carbon dioxide (C) originate from amine absorption and hydrogen (H) originate from water electrolysis, etc., and therefore have high purity, and also because the methanation reaction has high reaction selectivity.

[0043] As described above, gas monitoring system 100 facilitates monitoring of gas conditions in chemical processes.

[0044] 2. Configuration and processing of each device in the gas monitoring system 100 shown in Fig. 1 will be described using Fig. 2. Fig. 2 is a block diagram showing an example configuration of each device in the gas monitoring system 100 according to an embodiment. Below, an example configuration of the entire gas monitoring system 100 according to an embodiment, an example configuration and processing of the estimation device 10, an example configuration and processing of the operator terminal 20, and an example configuration and processing of the gas density meter 30 will be described.

[0045] (2-1. Example of the overall configuration of the gas monitoring system 100) An example of the overall configuration of the gas monitoring system 100 shown in Fig. 1 will be described using Fig. 2. As shown in Fig. 2, the gas monitoring system 100 has an estimation device 10, an operator terminal 20, and a gas density meter 30. The estimation device 10, the operator terminal 20, and the gas density meter 30 are communicatively connected via a communication network N realized by the Internet, a dedicated line, or the like.

[0046] The estimation device 10 is installed in a cloud environment, an on-premise environment, an edge environment, etc. The operator terminal 20 is installed in a monitoring room or the like that monitors a chemical process facility managed by an operator O. The gas density meter 30 is installed so as to be able to measure the piping that serves as a flow path for each gas in the chemical process.

[0047] (2-2. Configuration Example and Processing Example of Estimation Device 10) A configuration example and processing example of the estimation device 10 will be described with reference to Fig. 2. The estimation device 10 includes an input unit 11, an output unit 12, a communication unit 13, a storage unit 14, and a control unit 15.

[0048] (2-2-1. Input Unit 11) The input unit 11 controls input of various information to the estimation device 10. For example, the input unit 11 is realized by a mouse, a keyboard, or the like, and accepts input of various information to the estimation device 10.

[0049] (2-2-2. Output Unit 12) The output unit 12 controls the output of various information from the estimation device 10. For example, the output unit 12 is realized by a display or the like, and displays various information stored in the estimation device 10.

[0050] (2-2-3. Communication Unit 13) The communication unit 13 controls data communication with other devices. For example, the communication unit 13 performs data communication with each communication device via a router or the like. The communication unit 13 can also perform data communication with a terminal or the like (not shown).

[0051] (2-2-4. Storage Unit 14) The storage unit 14 stores various pieces of information referenced by the control unit 15 when it operates and various pieces of information acquired when the control unit 15 operates. The storage unit 14 includes a density data storage unit 14a, an estimation result storage unit 14b, and a prediction model storage unit 14c. Here, the storage unit 14 may be realized by, for example, a semiconductor memory element such as a random access memory (RAM) or a flash memory, or a storage device such as a hard disk or an optical disk. Note that, in the example of FIG. 2, the storage unit 14 is installed inside the estimation device 10, but it may also be installed outside the estimation device 10, or multiple storage units may be installed.

[0052] (2-2-4-1. Density Data Storage Unit 14a) The density data storage unit 14a stores density data. For example, the density data storage unit 14a stores the density of each gas measured by the gas density meter 30 and acquired by an acquisition unit 15a of the control unit 15, which will be described later. Here, an example of data stored in the density data storage unit 14a will be described with reference to FIG. 3. FIG. 3 is a diagram showing an example of the density data storage unit 14a of the estimation device 10 according to the embodiment. In the example of FIG. 3, the density data storage unit 14a has items such as "Monitoring Target" and "Density Data."

[0053] The "monitoring target" indicates identification information for identifying the chemical process to be monitored, such as an identification number or identification symbol of a chemical plant or a facility within the chemical plant. The "density data" indicates the density of the gas measured by the gas density meter 30, such as 1 m3 under standard conditions (1 atmosphere, 0°C). ３ Mass per kg / m ３ It is expressed as:

[0054] That is, Figure 3 shows an example in which, in a chemical process identified by a "monitoring target," the density data indicated by "density data 1" are "density data #1-1," "density data #1-2," "density data #1-3," ...; the density data indicated by "density data 2" are "density data #2-1," "density data #2-2," "density data #2-3," ...; the density data indicated by "density data 3" are "density data #3-1," "density data #3-2," "density data #3-3," ...; and the density data indicated by "density data 4" are "density data #4-1," "density data #4-2," "density data #4-3," ... are stored in the density data storage unit 14a.

[0055] The density data storage unit 14a can store density data for each flow path measured by the gas density meter 30, such as "density data 1," "density data 2," "density data 3," "density data 4," etc.

[0056] (2-2-4-2. Estimation result storage unit 14b) The estimation result storage unit 14b stores the estimation result. For example, the estimation result storage unit 14b stores the estimation result output by the estimation unit 15b of the control unit 15, which will be described later. Here, an example of data stored in the estimation result storage unit 14b will be described with reference to FIG. 4. FIG. 4 is a diagram showing an example of the estimation result storage unit 14b of the estimation device 10 according to the embodiment. In the example of FIG. 4, the estimation result storage unit 14b has items such as "monitoring target" and "estimation result."

[0057] The "monitoring target" indicates identification information for identifying the chemical process to be monitored, such as an identification number or identification symbol of a chemical plant or equipment within the chemical plant. The "estimation result" indicates the state of each gas estimated from the density data, such as an estimated value of the purity (%) of carbon dioxide C, an estimated value of the purity (%) of hydrogen H, an estimated value of the mixture ratio of carbon dioxide C and hydrogen H, and an estimated value of the reaction rate (%) of methane M.

[0058] That is, Figure 4 shows an example in which data such as the following is stored in the estimation result memory unit 14b in a chemical process identified by a "monitoring target": the estimation results indicated by "estimation result 1" are "estimation result #1-1," "estimation result #1-2," "estimation result #1-3," ...; the estimation results indicated by "estimation result 2" are "estimation result #2-1," "estimation result #2-2," "estimation result #2-3," ...; the estimation results indicated by "estimation result 3" are "estimation result #3-1," "estimation result #3-2," "estimation result #3-3," ...; and the estimation results indicated by "estimation result 4" are "estimation result #4-1," "estimation result #4-2," "estimation result #4-3," ...

[0059] The estimation result storage unit 14b can store estimation results for each density data, such as "estimation result 1," "estimation result 2," "estimation result 3," "estimation result 4," and so on.

[0060] (2-2-4-3. Prediction model storage unit 14c) The prediction model storage unit 14c stores a prediction model PM. For example, the prediction model storage unit 14c stores the prediction model PM, which is a machine learning model used by the estimation unit 15b of the control unit 15, which will be described later. Here, an example of data stored in the prediction model storage unit 14c will be described with reference to FIG. 5. FIG. 5 is a diagram illustrating an example of the prediction model storage unit 14c of the estimation device 10 according to the embodiment. In the example of FIG. 5, the prediction model storage unit 14c has an item such as "prediction model."

[0061] A "prediction model" is model data of a trained machine learning model, and is data that includes, for example, execution data for executing the algorithm of the prediction model PM that predicts the estimated results after a specified period of time, model parameters that are setting values, hyperparameters, etc.

[0062] FIG. 5 illustrates an example in which a plurality of trained prediction models PM, such as "prediction model #1," "prediction model #2," . . . , are stored in the prediction model storage unit 14c.

[0063] (2-2-5. Control Unit 15) The control unit 15 controls the entire estimation device 10. The control unit 15 has an acquisition unit 15a, an estimation unit 15b, and a notification unit 15c. Here, the control unit 15 can be realized by, for example, an electronic circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), or an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0064] (2-2-5-1. Acquisition unit 15a) The acquisition unit 15a acquires various types of information. The acquisition unit 15a may store the acquired various types of information in the storage unit 14. The acquisition control processes (first acquisition process, second acquisition process, third acquisition process, and fourth acquisition process) will be described below.

[0065] (Acquisition Control Process) The acquisition unit 15a executes an acquisition control process. For example, the acquisition unit 15a acquires the density of the gas measured by the gas density meter 30.

[0066] (First Acquisition Process) The acquisition unit 15a executes a first acquisition process as an acquisition control process. For example, the acquisition unit 15a acquires the density of a gas containing carbon dioxide C, which is a reactant before mixing in a methanation reaction.

[0067] To describe a specific example of the first acquisition process, the acquisition unit 15a acquires a density (kg / m) of a gas containing carbon dioxide C before mixing in a methanation reaction, the density being measured by a gas density meter 30 installed so as to be able to measure the flow path of the “monitoring target #1” which is a chemical process. ３ As density data indicating the density, "density data #1-1," "density data #1-2," "density data #1-3," . . . are acquired and stored in the density data storage unit 14a.

[0068] (Second Acquisition Process) The acquisition unit 15a executes a second acquisition process as an acquisition control process. The acquisition unit 15a acquires the density of a gas containing hydrogen H, which is a reactant before mixing in a methanation reaction.

[0069] To explain a specific example of the second acquisition process, the acquisition unit 15a acquires the density (kg / m) of the gas containing hydrogen H before mixing in the methanation reaction, which is a density measured by the gas density meter 30 installed so as to be able to measure the flow path of the “monitoring target #1” which is a chemical process. ３ As density data indicating the density, "density data #2-1," "density data #2-2," "density data #2-3," . . . are acquired and stored in the density data storage unit 14a.

[0070] (Third Acquisition Process) The acquisition unit 15a executes a third acquisition process as an acquisition control process. The acquisition unit 15a acquires the density of a gas containing carbon dioxide C and hydrogen H before the methanation reaction.

[0071] To describe a specific example of the third acquisition process, the acquisition unit 15a acquires a density (kg / m) of a mixed gas containing carbon dioxide C and hydrogen H before the methanation reaction, the density being measured by a gas density meter 30 installed so as to be able to measure the flow path of the “monitoring target #1” which is a chemical process. ３ As density data indicating the density, "density data #3-1," "density data #3-2," "density data #3-3," . . . are acquired and stored in the density data storage unit 14a.

[0072] (Fourth Obtaining Process) The obtaining unit 15a executes a fourth obtaining process as an obtaining control process. The obtaining unit 15a obtains the density of the gas containing the dehumidified methane M after the methanation reaction.

[0073] To explain a specific example of the fourth acquisition process, the acquisition unit 15a acquires the density (kg / m) of a mixed gas containing produced methane M, unreacted carbon dioxide C, and unreacted hydrogen H remaining after the mixed gas after the methanation reaction is dehumidified using an electronic dehumidifier or the like. The density is measured by a gas density meter 30 installed so as to be able to measure the flow path of the “monitoring target #1”, which is a chemical process. ３ As density data indicating the density, "density data #4-1," "density data #4-2," "density data #4-3," . . . are acquired and stored in the density data storage unit 14a.

[0074] (2-2-5-2. Estimation unit 15b) The estimation unit 15b outputs the estimation result. The estimation unit 15b may store the output estimation result in the storage unit 14. The estimation unit 15b may also refer to various information stored in the storage unit 14. The estimation control processes (first estimation process, second estimation process, third estimation process, fourth estimation process), estimation formula correction process, prediction control process, and reaction rate monitoring process will be described below.

[0075] (Estimation Control Process) The estimation unit 15b executes the estimation control process. For example, the estimation unit 15b estimates the state of the gas based on the acquired gas density and a linear relational expression. At this time, the estimation unit 15b estimates the purity of the gas from the acquired gas density using a linear relational expression that indicates the relationship between the gas density and the purity of the gas. The estimation unit 15b also estimates the state of the gas based on the acquired gas density and a nonlinear relational expression. At this time, the estimation unit 15b estimates the mixture ratio of the reactants from the acquired gas density using a nonlinear relational expression that indicates the relationship between the gas density and the mixture ratio of the reactants. The estimation unit 15b also estimates the reaction rate of the product from the acquired gas density using a nonlinear relational expression that indicates the relationship between the gas density and the reaction rate.

[0076] (First Estimation Process) The estimation unit 15b executes a first estimation process as an estimation control process. The estimation unit 15b estimates the purity of the carbon dioxide C from the acquired gas density using a linear relational expression that indicates the relationship between the gas density and the purity of the carbon dioxide C.

[0077] To describe a specific example of the first estimation process, the estimation unit 15b estimates the density (kg / m) of a gas containing carbon dioxide C before mixing in the methanation reaction of the “monitoring target #1”, which is a chemical process. ３ As density data indicating the purity of carbon dioxide C, "density data #1-1," "density data #1-2," "density data #1-3," ... stored in the density data storage unit 14a are referenced, and using estimation formula (1), which is a linear relational formula described later, "estimation result #1-1," "estimation result #1-2," "estimation result #1-3," ... are calculated as estimation results indicating the purity % of carbon dioxide C, and stored in the estimation result storage unit 14b.

[0078] Here, the estimation formula (1) used in the first estimation process will be described with reference to Fig. 6. Fig. 6 shows a specific example 1 of the estimation formula in the embodiment. The horizontal axis x in Fig. 6 represents the density (kg / m) of the gas containing carbon dioxide C. ３ The vertical axis y in FIG. 6 represents the purity % of carbon dioxide C. As shown below, the estimation formula (1) is expressed as a linear equation using x and y, i.e., a linear relational equation. Note that R represents the correlation coefficient.

[0079] Estimation formula (1): y=146.13x-188.92 (R ２ =1)

[0080] The above estimation formula (1) shows that the less air is mixed into the carbon dioxide C used as the raw material for the methanation reaction, the closer the density becomes to that of pure carbon dioxide C according to the linear relational expression. In the above estimation formula (1), the density of pure carbon dioxide C is 1.9771 kg / m under standard conditions (1 atmosphere, 0°C). ３ The density of pure air is 1.2928 kg / m under standard conditions (1 atmosphere, 0°C). ３ The repeatability of the gas density meter 30 is ±0.001 kg / m ３ (corresponding purity ±0.146%) or purity ±0.5%, whichever is larger, so the purity is ±0.5%.

[0081] (Second Estimation Process) The estimation unit 15b executes a second estimation process as an estimation control process. The estimation unit 15b estimates the purity of hydrogen H from the acquired gas density using a linear relational expression that indicates the relationship between the gas density and the purity of hydrogen H.

[0082] To describe a specific example of the second estimation process, the estimation unit 15b estimates the density (kg / m) of a gas containing hydrogen (H) before mixing in the methanation reaction of the “monitoring target #1”, which is a chemical process. ３As density data indicating the purity of hydrogen H, "density data #2-1," "density data #2-2," "density data #2-3," ... stored in the density data storage unit 14a are referenced, and "estimation result #2-1," "estimation result #2-2," "estimation result #2-3," ... are calculated as estimation results indicating the purity % of hydrogen H using estimation formula (2), which is a linear relational formula described later, and these are stored in the estimation result storage unit 14b.

[0083] Here, the estimation formula (2) used in the second estimation process will be described with reference to FIG. 7. FIG. 7 shows a specific example 2 of the estimation formula in the embodiment. The horizontal axis x in FIG. 7 represents the density (kg / m) of the gas containing hydrogen H. ３ The vertical axis y in FIG. 7 represents the purity (%) of hydrogen H. As shown below, the estimation formula (2) is expressed as a linear equation using x and y, i.e., a linear relational equation. R represents the correlation coefficient.

[0084] Estimation formula (2): y=-83.131x+107.47 (R ２ =1)

[0085] The above estimation formula (2) shows that the less air is mixed into hydrogen H, which is the raw material for the methanation reaction, the closer the density becomes to that of pure hydrogen H according to the linear relational expression. Note that in the above estimation formula (2), the density of pure hydrogen H is 0.08988 kg / m under standard conditions (1 atmosphere, 0°C). ３ The density of pure air is 1.2928 kg / m under standard conditions (1 atmosphere, 0°C). ３ The repeatability of the gas density meter 30 is ±0.001 kg / m ３ (equivalent purity ±0.083%) or purity ±0.5%, whichever is larger, so the purity is ±0.5%.

[0086] The estimation unit 15b executes a third estimation process as an estimation control process. The estimation unit 15b estimates the mixture ratio of the reactants, carbon dioxide C and hydrogen H, from the acquired gas density using a nonlinear relational expression that indicates the relationship between the gas density and the mixture ratio of the reactants.

[0087] To describe a specific example of the third estimation process, the estimation unit 15b estimates the density (kg / m) of a mixed gas containing carbon dioxide (C) and hydrogen (H) before the methanation reaction of the "monitoring target #1", which is a chemical process. ３ As density data indicating the mixture ratio of carbon dioxide C and hydrogen H, "density data #3-1," "density data #3-2," "density data #3-3," ... stored in the density data storage unit 14a are referenced, and "estimation result #3-1," "estimation result #3-2," "estimation result #3-3," ... are calculated as estimation results indicating the mixture ratio of carbon dioxide C and hydrogen H using estimation formula (3), which is a nonlinear relational formula described later, and are stored in the estimation result storage unit 14b.

[0088] Here, the estimation formula (3) used in the third estimation process will be described with reference to Fig. 8. Fig. 8 shows a specific example 3 of the estimation formula in the embodiment. The horizontal axis x in Fig. 8 represents the density (kg / m) of a mixed gas containing carbon dioxide (C) and hydrogen (H). ３ The vertical axis y in FIG. 8 indicates the ratio of the amount of substance of hydrogen H to carbon dioxide C, which is the mixture ratio of carbon dioxide C and hydrogen H. In the example of FIG. 8, the vertical axis y ranges from 2 to 6, with 4 being the stoichiometric ratio in the methanation reaction. As shown below, the estimation equation (3) is expressed as a quartic equation using x and y, i.e., a nonlinear relational equation. Note that R indicates the correlation coefficient.

[0089] Estimation formula (3): y = 138.53x ４ -355.85x ３ +345.15x ２ -167.68x+34.724 (R ２ =1)

[0090] The above estimation formula (3) indicates that in a mixed gas of carbon dioxide C and hydrogen H, which are used as raw materials for the methanation reaction, the larger the ratio of the amount of substance of hydrogen H to carbon dioxide C, the closer the density approaches that of pure hydrogen H according to a quartic relational expression. On the other hand, the above estimation formula (3) indicates that the smaller the ratio of the amount of substance of hydrogen H to carbon dioxide C, the closer the density approaches that of pure carbon dioxide C according to a quartic relational expression. Furthermore, the above estimation formula (3) can be corrected based on at least one of the estimated purity % of carbon dioxide C and the estimated purity % of hydrogen H by the estimation formula correction process described below. Note that in the above estimation formula (3), the density of pure carbon dioxide C is 1.9771 kg / m at standard conditions (1 atmosphere, 0°C). ３ The density of pure hydrogen H is 0.08988 kg / m under standard conditions (1 atmosphere, 0°C). ３ The repeatability of the gas density meter 30 is ±0.001 kg / m ３ or purity ±0.5% (equivalent density ±0.00375 kg / m ３ ) is the larger of the two, so the purity is ±0.5%, which is ±0.04 when converted to the average value of the equivalent ratio in the mixed gas of carbon dioxide C and hydrogen H.

[0091] (Fourth Estimation Process) The estimation unit 15b executes a fourth estimation process as an estimation control process. The estimation unit 15b estimates the reaction rate of the product methane M from the acquired gas density using a nonlinear relational expression that indicates the relationship between the gas density and the reaction rate.

[0092] To describe a specific example of the fourth estimation process, the estimation unit 15b estimates the density (kg / m) of a mixed gas containing methane M, carbon dioxide C, and hydrogen H after the methanation reaction of the “monitoring target #1”, which is a chemical process. ３ As density data indicating the reaction rate % of methane M, "density data #4-1," "density data #4-2," "density data #4-3," ... stored in the density data storage unit 14a are referenced, and "estimation result #4-1," "estimation result #4-2," "estimation result #4-3," ... are calculated as estimation results indicating the reaction rate % of methane M using estimation formula (4), which is a nonlinear relational formula described later, and are stored in the estimation result storage unit 14b.

[0093] Here, the estimation formula (4) used in the fourth estimation process will be described with reference to Fig. 9. Fig. 9 shows a specific example 4 of the estimation formula in the embodiment. The horizontal axis x in Fig. 9 represents the density (kg / m) of a mixed gas of methane M, carbon dioxide C, and hydrogen H. ３ The density of the gas mixture is kg / m ３ is the water (H ２ 9 is the density after dehumidification and removal of the condensed water (water). The vertical axis y in FIG. 9 represents the reaction rate (%) of the methanation reaction. As shown below, the estimation formula (4) is expressed as a sextic formula using x and y, i.e., a nonlinear relational formula. Note that R represents the correlation coefficient.

[0094] Estimation formula (4): y = -3.4891 x 10 ６ x ６ +1.2848 x 10 ７ x ５ -1.9683 x 10 ７ x ４ +1.6066 x 10 ７ x ３ -7.3718 x 10 ６ x ２ +1.8043 x 10 ６ x-1.8415×10 ５ (R ２ = 0.99999)

[0095] The above estimation formula (4) shows that in a mixed gas of methane M, carbon dioxide C, and hydrogen H after the methanation reaction, the greater the amount of methane M produced, i.e., the greater the reaction rate of methane M, the closer the density approaches that of pure methane M according to the sextic relational expression. Furthermore, the above estimation formula (4) can be corrected based on the estimated mixture ratio of carbon dioxide C and hydrogen H by the estimation formula correction process described below. In addition, in the above estimation formula (4), the density of pure carbon dioxide C is 1.9771 kg / m under standard conditions (1 atmosphere, 0°C). ３ The density of pure hydrogen H is 0.08988 kg / m under standard conditions (1 atmosphere, 0°C). ３The density of pure methane M is 0.7175 kg / m under standard conditions (1 atmosphere, 0°C). ３ The repeatability of the gas density meter 30 is ±0.001 kg / m ３ or purity ±0.5% (equivalent density ±0.00375 kg / m ３ ), which is the larger of the two, the purity is ±0.5%, which when converted to the average equivalent reaction rate in a mixed gas of methane M, carbon dioxide C, and hydrogen H is ±1.6% (range: ±0.5 to ±3.9%).

[0096] (Estimated Equation Correction Process) The estimation unit 15b executes the estimated equation correction process. The estimation unit 15b corrects the nonlinear relational equation based on the estimated gas state. Below, as the estimated equation correction process, correction of the estimated equations E(3) and E(4), which are nonlinear relational equations, will be described.

[0097] The correction process of the estimation formula E(3) will be described below. For example, the estimation unit 15b corrects the estimation formula E(3) that estimates the mixture ratio of carbon dioxide C and hydrogen H based on at least one of the estimated purity % of carbon dioxide C and the estimated purity % of hydrogen H. At this time, for example, when the estimated purity % of carbon dioxide C is small, the estimation unit 15b corrects the estimation formula E(3) so that the ratio of carbon dioxide C in the mixed gas becomes small. Furthermore, for example, when the estimated purity % of hydrogen H is small, the estimation unit 15b corrects the estimation formula E(3) so that the ratio of hydrogen H in the mixed gas becomes small.

[0098] The correction process of the estimation formula E(3) will be described. For example, the estimation unit 15b corrects the estimation formula E(4) that estimates the reaction rate % of methane M based on the estimated mixture ratio of carbon dioxide C and hydrogen H. At this time, if the estimated substance amount ratio of hydrogen H to carbon dioxide C significantly deviates from the stoichiometric ratio, for example, the estimation unit 15b corrects the estimation formula E(4) so ​​that the reaction rate % of methane M approaches the actual measured value.

[0099] (Predictive Control Process) The estimation unit 15b executes a predictive control process. The estimation unit 15b uses a prediction model PM that outputs a gas state in response to an input of the gas density to estimate a gas state after a predetermined period of time from the acquired gas density. For example, the estimation unit 15b uses a prediction model PM that outputs a methane M reaction rate in response to an input of the gas density to estimate a methane M reaction rate after a predetermined period of time from the acquired gas density.

[0100] To explain a specific example of the predictive control process, the estimation unit 15b estimates the density (kg / m) of a mixed gas containing methane M, carbon dioxide C, and hydrogen H after the methanation reaction of the “monitoring target #1”, which is a chemical process. ３ The density data indicating the reaction rate of methane M after a predetermined period of time is estimated by referring to the density data stored in the density data storage unit 14a ("density data #4-1," "density data #4-2," and "density data #4-3"), and inputting the data into the "prediction model #1" stored in the prediction model storage unit 14c to output "estimated result #4-4."

[0101] The estimation unit 15b can also estimate the purity of carbon dioxide C after a predetermined period of time from the acquired gas density using a prediction model PM that outputs the purity of carbon dioxide C in response to an input of the gas density. The estimation unit 15b can also estimate the purity of hydrogen H after a predetermined period of time from the acquired gas density using a prediction model PM that outputs the purity of hydrogen H in response to an input of the gas density. The estimation unit 15b can also estimate the mixing ratio of carbon dioxide C and hydrogen H after a predetermined period of time from the acquired gas density using a prediction model PM that outputs the mixing ratio of reactants in response to an input of the gas density.

[0102] (Reaction Rate Monitoring Process) The estimation unit 15b executes a reaction rate monitoring process. The estimation unit 15b monitors time-series changes in the estimated reaction rate of methane M. For example, the estimation unit 15b executes unsteady state monitoring, steady state monitoring, and reaction rate decline monitoring.

[0103] Here, the reaction rate monitoring process will be described with reference to Fig. 10. Fig. 10 is a diagram showing a specific example of a time series change in methane M according to the embodiment. The horizontal axis of Fig. 10 represents time. The vertical axis of Fig. 10 represents the reaction rate of the methanation reaction, i.e., the methane concentration.

[0104] First, the estimation unit 15b performs unsteady state monitoring as the reaction rate monitoring process. That is, the estimation unit 15b estimates the unsteady state (see FIG. 10(1)) at the start of the methanation reaction when the reaction rate is low immediately after the reaction, based on the reaction rate variance s ２ This is monitored by calculating the following:

[0105] Second, the estimation unit 15b performs steady state monitoring as the reaction rate monitoring process. That is, the estimation unit 15b estimates a non-steady state (see FIG. 10(2)) in which the reaction rate of the methanation reaction is stable at a high level by using the reaction rate value, the reaction rate variance s ２ This is monitored by calculating the following:

[0106] Third, the estimation unit 15b performs reaction rate decline monitoring as a reaction rate monitoring process. That is, the estimation unit 15b estimates a state in which the reaction rate declines due to catalyst deterioration in the methanation reaction or heat generation due to the reaction (see FIG. 10(3)) using the numerical value of the reaction rate, the reaction rate variance s ２ The monitoring is performed by calculating the difference from the steady state, the integration, etc.

[0107] (2-2-5-3. Notification unit 15c) The notification unit 15c notifies various types of information. Note that the notification unit 15c may refer to various types of information stored in the storage unit 14. The notification control process (first notification process, second notification process, third notification process, fourth notification process) and the alarm notification process will be described.

[0108] (Notification Control Process) The notification unit 15c executes the notification control process. The notification unit 15c notifies a user of the estimated gas state. For example, the notification unit 15c notifies an operator O, who is a manager of the chemical process, of the estimation result output by the estimation unit 15b.

[0109] (First Notification Process) The notification unit 15c executes a first notification process as a notification control process. The notification unit 15c notifies the user of the purity of the carbon dioxide C estimated by the estimation unit 15b.

[0110] To explain a specific example of the first notification process, the notification unit 15c refers to the estimation result memory unit 14b and transmits the estimated purity of carbon dioxide C as “Estimation result #1-1,” “Estimation result #1-2,” “Estimation result #1-3,” etc. to the operator terminal 20, and displays them on the display of the operator terminal 20.

[0111] (Second Notification Process) The notification unit 15c executes the second notification process as the notification control process. The notification unit 15c notifies the user of the purity of hydrogen H estimated by the estimation unit 15b.

[0112] To explain a specific example of the second notification process, the notification unit 15c refers to the estimation result memory unit 14b, transmits the estimated purity of hydrogen H as “Estimation result #2-1,” “Estimation result #2-2,” “Estimation result #2-3,” etc. to the operator terminal 20, and displays them on the display of the operator terminal 20.

[0113] (Third Notification Process) The notification unit 15c executes a third notification process as a notification control process, in which the notification unit 15c notifies the user of the mixture ratio of carbon dioxide C and hydrogen H estimated by the estimation unit 15b.

[0114] To explain a specific example of the third notification process, the notification unit 15c refers to the estimation result memory unit 14b, transmits the estimated mixture ratios of carbon dioxide C and hydrogen H as “Estimation result #3-1,” “Estimation result #3-2,” “Estimation result #3-3,” etc. to the operator terminal 20, and displays them on the display of the operator terminal 20.

[0115] (Fourth Notification Process) The notification unit 15c executes a fourth notification process as a notification control process. The notification unit 15c notifies the user of the reaction rate of methane M estimated by the estimation unit 15b.

[0116] To explain a specific example of the fourth notification process, the notification unit 15c refers to the estimation result memory unit 14b, transmits ``Estimation result #4-1,'' ``Estimation result #4-2,'' ``Estimation result #4-3,'' etc. as the estimated reaction rates of methane M to the operator terminal 20, and displays them on the display of the operator terminal 20.

[0117] (Alarm Notification Process) The notification unit 15c executes alarm notification process. The notification unit 15c issues an alarm to the user when a numerical value indicating the state of a gas is not within a predetermined range defined for each gas. For example, when the estimated purity of carbon dioxide C is below a predetermined value, the notification unit 15c issues an alarm to the operator O indicating that an abnormality has occurred during the supply of carbon dioxide C. Furthermore, when the estimated purity of hydrogen H is below a threshold, the notification unit 15c issues an alarm to the operator O indicating that an abnormality has occurred during the supply of hydrogen H. Furthermore, when the estimated mixing ratio of carbon dioxide C to hydrogen H is below a lower threshold or equal to or greater than an upper threshold, the notification unit 15c issues an alarm to the operator O indicating that an abnormality has occurred during the methanation reaction. Furthermore, when the estimated reaction rate of methane M is below a threshold, the notification unit 15c issues an alarm to the operator O indicating that an abnormality has occurred during the methanation reaction.

[0118] (2-3. Example of Configuration and Processing of Operator Terminal 20) An example of configuration and processing of the operator terminal 20 will be described with reference to Fig. 2 again. The operator terminal 20 has an input / output unit 21, a transmitting / receiving unit 22, and a communication unit 23.

[0119] (2-3-1. Input / Output Unit 21) The input / output unit 21 controls the input of various types of information to the operator terminal 20. For example, the input / output unit 21 is realized by a mouse, a keyboard, a touch panel, or the like, and accepts input of various types of information to the operator terminal 20. The input / output unit 21 also controls the display of various types of information from the operator terminal 20. For example, the input / output unit 21 is realized by a display, or the like, and displays various types of information stored in the operator terminal 20. The input / output unit 21 also displays estimation results and alarms transmitted from the estimation device 10.

[0120] (2-3-2. Transmitter / Receiver 22) The transmitter / receiver 22 transmits various types of information. For example, the transmitter / receiver 22 transmits a transmission request for an estimation result input by the operator O to the estimation device 10. The transmitter / receiver 22 also receives various types of information. For example, the transmitter / receiver 22 receives an estimation result or an alarm transmitted from the estimation device 10.

[0121] (2-3-3. Communication Unit 23) The communication unit 23 controls data communication with other devices. For example, the communication unit 23 performs data communication with each communication device via a router or the like. The communication unit 23 can also perform data communication with a terminal (not shown).

[0122] (2-4. Configuration and Processing Examples of Gas Density Meter 30) Referring again to FIG. 2 , a configuration and processing example of the gas density meter 30 will be described. For example, the gas density meter 30 is realized by a vibration-type gas densitometer for chemical processes that uses the principle that the resonance frequency of a thin-walled cylinder changes depending on the gas density around the cylinder. The gas densitometer 30 is installed in two or more pipes that are each a flow path in the chemical process of a methanation reaction so that the density of any gas can be measured by switching the flow path with a flow path switching unit. In this case, the gas densitometer 30 may be installed in each of the two or more pipes that are each a flow path in the chemical process of a methanation reaction.

[0123] The gas densitometer 30 measures the density of each gas in the chemical process of the methanation reaction. For example, the gas densitometer 30 measures the density of a gas containing carbon dioxide (C), which is a reactant before mixing in the methanation reaction, and transmits the result to the estimation device 10. The gas densitometer 30 also measures the density of a gas containing hydrogen (H), which is a reactant before mixing in the methanation reaction, and transmits the result to the estimation device 10. The gas densitometer 30 also measures the density of a gas containing carbon dioxide (C) and hydrogen (H), which is a mixed gas before the reaction in the methanation reaction, and transmits the result to the estimation device 10. The gas densitometer 30 also measures the density of a gas containing methane (M), carbon dioxide (C), and hydrogen (H), which is a mixed gas after the reaction and dehumidification in the methanation reaction, and transmits the result to the estimation device 10.

[0124] 11 to 14, the process flow of the gas monitoring system 100 according to the embodiment will be described. Below, the overall process flow of the gas monitoring system 100 will be described, followed by a description of each process, namely, the acquisition control process, the estimation control process, and the notification control process.

[0125] (3-1. Overall Processing of Gas Monitoring System 100) The overall processing flow of the gas monitoring system 100 according to the embodiment will be described using FIG. 11. FIG. 11 is a flowchart showing an example of the overall processing flow of the gas monitoring system 100 according to the embodiment. Note that the processing of steps S101 to S103 below can also be executed in a different order. Furthermore, some of the processing of steps S101 to S103 below may be omitted.

[0126] (3-1-1. Acquisition Control Process) First, the gas monitoring system 100 executes an acquisition control process (step S101). For example, the gas monitoring system 100 executes the processes of steps S201 to S204 described below to acquire the density of each gas measured by the gas density meter 30.

[0127] (3-1-2. Estimation Control Process) Second, the gas monitoring system 100 executes an estimation control process (step S102). For example, the gas monitoring system 100 executes the processes of steps S301 to S304 described below to estimate the state of each gas based on the acquired density of each gas and the estimation formula.

[0128] (3-1-3. Notification Control Processing) Third, the gas monitoring system 100 executes the notification control processing (step S103) and ends the processing. For example, the gas monitoring system 100 notifies the user of the estimated state of each gas by executing the processing of steps S401 to S404 described below.

[0129] (3-2. Acquisition Control Processing) The flow of the acquisition control processing of the gas monitoring system 100 according to the embodiment will be described using FIG. 12. FIG. 12 is a flowchart showing an example of the flow of the acquisition control processing of the gas monitoring system 100 according to the embodiment. Note that the processing of steps S201 to S204 below can also be executed in a different order. Furthermore, some of the processing of steps S201 to S204 below may be omitted.

[0130] (3-2-1. First Obtaining Process) First, the estimation device 10 executes a first obtaining process (step S201). For example, the estimation device 10 obtains the density of the gas containing carbon dioxide C before mixing in the methanation reaction from the gas density meter 30.

[0131] (3-2-2. Second Acquisition Process) Second, the estimation device 10 executes a second acquisition process (step S202). For example, the estimation device 10 acquires the density of the gas containing hydrogen H before mixing in the methanation reaction from the gas density meter 30.

[0132] (3-2-3. Third Obtaining Process) Third, the estimation apparatus 10 executes a third obtaining process (step S203). For example, the estimation apparatus 10 obtains the density of the gas containing carbon dioxide C and hydrogen H before the methanation reaction from the gas density meter 30.

[0133] (3-2-4. Fourth Acquisition Process) Fourth, the estimation device 10 executes a fourth acquisition process (step S204) and ends the acquisition control process. For example, the estimation device 10 acquires the density of the gas containing methane M after the methanation reaction and after dehumidification from the gas density meter 30.

[0134] (3-3. Estimation Control Processing) The flow of the estimation control processing of the gas monitoring system 100 according to the embodiment will be described using FIG. 13. FIG. 13 is a flowchart showing an example of the flow of the estimation control processing of the gas monitoring system 100 according to the embodiment. Note that the processing of steps S301 to S304 below can also be executed in a different order. Furthermore, some of the processing of steps S301 to S304 below may be omitted.

[0135] (3-3-1. First Estimation Process) First, the estimation device 10 executes a first estimation process (step S301). For example, the estimation device 10 estimates the purity of carbon dioxide C from the acquired gas density using estimation formula (1) that shows the relationship between the gas density and the purity of carbon dioxide C.

[0136] (3-3-2. Second Estimation Process) Second, the estimation device 10 executes the second estimation process (step S302). For example, the estimation device 10 estimates the purity of hydrogen H from the acquired gas density using estimation formula (2) that shows the relationship between the gas density and the purity of hydrogen H.

[0137] (3-3-3. Third Estimation Process) Third, the estimation device 10 executes a third estimation process (step S303). For example, the estimation device 10 estimates the mixture ratio of carbon dioxide C and hydrogen H from the acquired gas density using estimation formula (3) that shows the relationship between the gas density and the mixture ratio of the reactants. At this time, the estimation device 10 may correct estimation formula E(3) based on at least one of the estimated purity of carbon dioxide C and the estimated purity of hydrogen H.

[0138] (3-3-4. Fourth Estimation Process) Fourth, the estimation device 10 executes a fourth estimation process (step S304) and ends the estimation control process. For example, the estimation device 10 estimates the reaction rate of methane M from the acquired gas density using estimation formula (4) that shows the relationship between the gas density and the reaction rate of methane M. At this time, the estimation device 10 may correct estimation formula E(4) based on the estimated mixture ratio of carbon dioxide C and hydrogen H.

[0139] (3-4. Notification Control Processing) The flow of notification control processing in the gas monitoring system 100 according to the embodiment will be described using FIG. 14. FIG. 14 is a flowchart showing an example of the flow of notification control processing in the gas monitoring system 100 according to the embodiment. Note that the processing in steps S401 to S404 below can also be executed in a different order. Furthermore, some of the processing in steps S401 to S404 below may be omitted.

[0140] (3-4-1. First Notification Process) First, the estimation device 10 executes the first notification process (step S401). For example, the estimation device 10 notifies the operator O of the purity of carbon dioxide C as the estimated gas state. Furthermore, if the estimated purity of carbon dioxide C is not within a predetermined range, the estimation device 10 notifies the operator O of an alarm.

[0141] (3-4-2. Second Notification Process) Second, the estimation device 10 executes the second notification process (step S402). For example, the estimation device 10 notifies the operator O of the purity of hydrogen H as the estimated gas state. Furthermore, if the estimated purity of hydrogen H is not within a predetermined range, the estimation device 10 notifies the operator O of an alarm.

[0142] (3-4-3. Third Notification Process) Third, the estimation device 10 executes the third notification process (step S403). For example, the estimation device 10 notifies the operator O of the mixture ratio of carbon dioxide C and hydrogen H as the estimated gas state. Furthermore, if the estimated mixture ratio of carbon dioxide C and hydrogen H is not within a predetermined range, the estimation device 10 notifies the operator O of an alarm.

[0143] (3-4-4. Fourth Notification Process) Fourth, the estimation device 10 executes a fourth notification process (step S404) and ends the notification control process. For example, the estimation device 10 notifies the operator O of the reaction rate of methane M as the estimated gas state. Furthermore, if the estimated reaction rate of methane M is not within a predetermined range, the estimation device 10 notifies the operator O of an alarm.

[0144] 4. Effects of the embodiment The effects of the embodiment will be described below. Effects 1 to 8 corresponding to the processing according to the embodiment will be described below.

[0145] (4-1. Effect 1) First, in the process according to the embodiment described above, the estimation device 10 acquires the density of the gas measured by the gas density meter 30 and estimates the state of the gas based on the acquired density of the gas and a nonlinear relational expression. Therefore, in this process, the state of the gas can be easily monitored in a chemical process.

[0146] (4-2. Effect 2) Secondly, in the process according to the above-described embodiment, the estimation device 10 acquires the density of the gas containing methane M, which is a product of the methanation reaction after the reaction and dehumidification, and estimates the reaction rate of methane M from the acquired gas density using a nonlinear relational expression that indicates the relationship between the gas density and the reaction rate of methane M. Therefore, in this process, the reaction rate of methane M in the methanation reaction can be estimated from the gas density, making it possible to easily monitor the state of the gas in a chemical process.

[0147] (4-3. Effect 3) Third, in the process according to the above-described embodiment, the estimation device 10 acquires the density of a gas containing carbon dioxide (C) and hydrogen (H), which are reactants in a methanation reaction, before the reaction, and estimates the mixture ratio of carbon dioxide (C) and hydrogen (H) from the acquired gas density using a nonlinear relational expression that indicates the relationship between the gas density and the mixture ratio of the reactants. Therefore, in this process, the mixture ratio of carbon dioxide (C) and hydrogen (H), which are raw materials for the methanation reaction, can be estimated from the gas density, making it possible to easily monitor the state of gas in a chemical process.

[0148] (4-4. Effect 4) Fourth, in the process according to the above-described embodiment, the estimation device 10 acquires the density of a gas containing carbon dioxide C, which is a reactant before mixing in a methanation reaction, and estimates the purity of the carbon dioxide C from the acquired gas density using a linear relational equation that shows the relationship between the gas density and the purity of the carbon dioxide C. Therefore, in this process, the purity of carbon dioxide C, which is a raw material for the methanation reaction, can be estimated from the gas density, making it possible to easily monitor the state of the gas in a chemical process.

[0149] (4-5. Effect 5) Fifth, in the process according to the above-described embodiment, the estimation device 10 acquires the density of the gas containing hydrogen H, which is a reactant before mixing in the methanation reaction, and estimates the purity of hydrogen H from the acquired gas density using a linear relational expression that shows the relationship between the gas density and the purity of hydrogen H. Therefore, in this process, the purity of hydrogen H, which is a raw material for the methanation reaction, can be estimated from the gas density, making it possible to easily monitor the state of gas in a chemical process.

[0150] (4-6. Effect 6) Sixth, in the process according to the above-described embodiment, the estimation device 10 corrects the nonlinear relational expression based on the estimated gas state. Therefore, in this process, the reaction rate of methane M can be estimated with high accuracy from the gas density based on the purity and mixing ratio of the raw materials for the methanation reaction, making it easy to monitor the gas state in a chemical process.

[0151] (4-7. Effect 7) Seventh, in the process according to the embodiment described above, the estimation device 10 estimates the gas state after a predetermined period of time from the acquired gas density using a prediction model that outputs the gas state in response to an input of the gas density. Therefore, this process makes it possible to easily monitor the gas state in a chemical process by making it possible to predict the future methanation reaction.

[0152] (4-8. Effect 8) Eighth, in the process according to the embodiment described above, the estimated gas state is notified to the operator O, and an alarm is issued to the operator O if the numerical value indicating the gas state is not within a predetermined range defined for each gas. Therefore, in this process, it is possible to grasp the time-series changes in the methanation reaction, thereby making it possible to easily monitor the gas state in a chemical process.

[0153] 5. Application Examples of the Embodiments Application examples of the embodiment will be described below. Application examples 1 and 2 of the embodiment will be described below.

[0154] (5-1. Application Example 1) As Application Example 1 of the embodiment, it is possible to apply not only to methanation reactions but also to methanol synthesis in CCUS (Carbon dioxide Capture, Utilization and Storage).

[0155] (5-2. Application Example 2) As an application example 2 of the embodiment, it is possible to apply not only the methanation reaction but also a chemical process in which the purity of the raw material components is high and the reaction selectivity is high.

[0156] [6. System] Information including processing procedures, control procedures, specific names, various data and parameters shown in the above documents and drawings may be changed as desired unless otherwise specified.

[0157] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown. In other words, the specific form of distribution and integration of each device is not limited to that shown. In other words, all or part of the devices can be functionally or physically distributed or integrated in any unit depending on various loads, usage conditions, etc.

[0158] Furthermore, all or any part of the processing functions performed by each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware using wired logic.

[0159] [7. Hardware] Next, an example of the hardware configuration of the estimation device 10 will be described. Note that other devices may also have a similar hardware configuration. FIG. 15 is a diagram showing an example of the hardware configuration according to an embodiment. As shown in FIG. 15, the estimation device 10 includes a communication device 10a, a hard disk drive (HDD) 10b, a memory 10c, and a processor 10d. The components shown in FIG. 15 are connected to each other via a bus or the like.

[0160] The communication device 10a is a network interface card or the like, and communicates with other servers. The HDD 10b stores programs and databases that operate the functions shown in FIG.

[0161] The processor 10d reads out a program that executes the same processes as the respective processing units shown in FIG. 2 from the HDD 10b or the like and loads it into the memory 10c, thereby operating a process that executes the respective functions described in FIG. 2 or the like. For example, this process executes the same functions as the respective processing units of the estimation device 10. Specifically, the processor 10d reads out a program that has the same functions as the acquisition unit 15a, the estimation unit 15b, the notification unit 15c, etc. from the HDD 10b or the like. Then, the processor 10d executes a process that executes the same processes as the acquisition unit 15a, the estimation unit 15b, the notification unit 15c, etc.

[0162] In this way, the estimation device 10 operates as a device that executes various processing methods by reading and executing a program. The estimation device 10 can also realize functions similar to those of the above-described embodiment by reading the program from a recording medium using a medium reading device and executing the read program. Note that the program in these other embodiments is not limited to being executed by the estimation device 10. For example, the present invention can also be applied in a similar manner to cases where another computer or server executes the program, or where these execute the program in cooperation with each other.

[0163] This program can be distributed via a network such as the Internet. In addition, this program can be recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, a magneto-optical disk (MO), or a digital versatile disk (DVD), and can be read out from the recording medium and executed by a computer.

[0164] [8. Others] Some examples of combinations of the disclosed technical features are described below.

[0165] (1) An estimation device comprising: an acquisition unit that acquires the density of a gas measured by a gas density meter; and an estimation unit that estimates the state of the gas based on the acquired density and a nonlinear relational expression.

[0166] (2) The estimation device described in (1), wherein the acquisition unit acquires the density of the gas containing methane, which is a product of a methanation reaction after the reaction and dehumidification, and the estimation unit estimates the reaction rate of the methane from the acquired density using the nonlinear relational expression that indicates the relationship between the density and the reaction rate of the methane.

[0167] (3) The estimation device described in (1) or (2), wherein the acquisition unit acquires the density of the gas containing carbon dioxide and hydrogen as reactants before the reaction in the methanation reaction, and the estimation unit estimates the mixing ratio of the carbon dioxide and the hydrogen from the acquired density using the nonlinear relational equation that shows the relationship between the density and the mixing ratio of the reactants.

[0168] (4) The estimation device described in (2) or (3), wherein the acquisition unit acquires the density of the gas containing carbon dioxide, which is a reactant before mixing in the methanation reaction, and the estimation unit estimates the purity of the carbon dioxide from the acquired density using a linear relational equation showing the relationship between the density and the purity of the carbon dioxide.

[0169] (5) An estimation device described in any one of (2) to (4), wherein the acquisition unit acquires the density of the gas containing hydrogen, which is a reactant before mixing in the methanation reaction, and the estimation unit estimates the purity of the hydrogen from the acquired density using a linear relational equation that shows the relationship between the density and the purity of the hydrogen.

[0170] (6) The estimation device according to any one of (1) to (5), wherein the estimation unit corrects the nonlinear relational expression based on the estimated state.

[0171] (7) An estimation device described in any one of (1) to (6), wherein the estimation unit estimates the state after a predetermined period from the acquired density using a prediction model that outputs the state in response to an input of the density.

[0172] (8) An estimation device described in any one of (1) to (7), further comprising a notification unit that notifies a user of the estimated state and notifies the user of an alarm if the numerical value indicating the state is not within a predetermined range defined for each of the gases.

[0173] (9) An estimation method in which a computer executes a process to acquire the density of a gas measured by a gas densitometer and estimate the state of the gas based on the acquired density and a nonlinear relational expression.

[0174] (10) An estimation program that causes a computer to execute a process of acquiring the density of a gas measured by a gas density meter and estimating the state of the gas based on the acquired density and a nonlinear relational expression.

[0175] REFERENCE SIGNS LIST 10 Estimation device 10a Communication device 10b HDD 10c Memory 10d Processor 11 Input unit 12 Output unit 13 Communication unit 14 Storage unit 14a Density data storage unit 14b Estimation result storage unit 14c Prediction model storage unit 15 Control unit 15a Acquisition unit 15b Estimation unit 15c Notification unit 20 Operator terminal 21 Input / output unit 22 Transmitting / receiving unit 23 Communication unit 30 Gas density meter 100 Gas monitoring system C Carbon dioxide H Hydrogen M Methane N Communication network O Operator

Claims

1. An estimation device comprising: an acquisition unit that acquires the density of a gas measured by a gas density meter; and an estimation unit that estimates the state of the gas based on the acquired density and a nonlinear relational expression.

2. The estimation device according to claim 1, wherein the acquisition unit acquires the density of the gas containing methane as a product after dehumidification following a methanation reaction, and the estimation unit estimates the reaction rate of methane from the acquired density using the nonlinear relational expression that indicates the relationship between the density and the reaction rate of methane.

3. The estimation device according to claim 1, wherein the acquisition unit acquires the density of the gas containing carbon dioxide and hydrogen as reactants before the methanation reaction, and the estimation unit estimates the mixture ratio of the carbon dioxide and hydrogen from the acquired density using the nonlinear relational expression that indicates the relationship between the density and the mixture ratio of the reactants.

4. The estimation device described in claim 2 or 3, wherein the acquisition unit acquires the density of the gas containing carbon dioxide, which is a reactant before mixing in the methanation reaction, and the estimation unit estimates the purity of the carbon dioxide from the acquired density using a linear relational equation that shows the relationship between the density and the purity of the carbon dioxide.

5. The estimation device described in claim 2 or 3, wherein the acquisition unit acquires the density of the gas containing hydrogen, a reactant before mixing in the methanation reaction, and the estimation unit estimates the purity of the hydrogen from the acquired density using a linear relational equation that shows the relationship between the density and the purity of the hydrogen.

6. The estimation device according to claim 1, wherein the estimation unit corrects the nonlinear relational expression based on the estimated state.

7. The estimation device according to claim 1, wherein the estimation unit estimates the state after a predetermined period from the acquired density using a prediction model that outputs the state in response to an input of the density.

8. The estimation device according to claim 1, further comprising a notification unit that notifies a user of the estimated state and issues an alarm to the user if the numerical value indicating the state is not within a predetermined range defined for each gas.

9. An estimation method in which a computer executes a process of acquiring the density of a gas measured by a gas densitometer, and estimating the state of the gas based on the acquired density and a nonlinear relational expression.

10. An estimation program that causes a computer to execute a process of acquiring the density of a gas measured by a gas density meter, and estimating the state of the gas based on the acquired density and a nonlinear relational expression.