Gas separation system and method for measuring carbon dioxide concentration thereof

Abstract

In a gas separation system that separates and recovers carbon dioxide from a process gas containing carbon dioxide, this invention provides a technology for measuring the carbon dioxide concentration of the recovered gas containing carbon dioxide separated from the process gas, which can reduce costs. [Solution] The gas separation system comprises a recovery gas line through which a recovery gas containing carbon dioxide separated from a process gas containing carbon dioxide flows, a recovery gas oxygen concentration meter connected inline to the recovery gas line to measure the oxygen concentration of the recovery gas in the recovery gas line, and a carbon dioxide concentration calculator that calculates an estimated value of the carbon dioxide concentration of the recovery gas based on the oxygen concentration of the recovery gas measured by the recovery gas oxygen concentration meter.

Description

[Technical Field]

[0001] This disclosure relates to a gas separation system and method for separating carbon dioxide (CO2) from a gas containing carbon dioxide, and more particularly to a technique for detecting the concentration of carbon dioxide separated by the gas separation system. [Background technology]

[0002] Direct air capture (DAC), a technology that directly separates and recovers carbon dioxide from the atmosphere, is attracting attention as a technology for reducing greenhouse gases. For example, Patent Document 1 discloses a gas separation unit that can be applied to DAC.

[0003] The gas separation unit disclosed in Patent Document 1 comprises a plurality of stacked adsorption layers, a gas inlet manifold, and a gas outlet manifold. Each adsorption layer has granular adsorbent material and a sheet sandwiching the adsorbent material. The gas flow path between the gas inlet manifold and the gas outlet manifold is configured to pass through at least one adsorption layer. A gas flow containing carbon dioxide flows into the gas inlet manifold, passes through the adsorption layers, and the carbon dioxide is adsorbed onto the adsorbent material and separated, then flows out through the gas outlet manifold. The carbon dioxide adsorbed onto the adsorbent material is desorbed from the adsorbent material by reducing the pressure inside the container containing the adsorbent material with a vacuum pump and heating the adsorbent material. The carbon dioxide desorbed from the adsorbent material is included in the desorbed gas flow discharged from the container by the vacuum pump. The mass flow rate of carbon dioxide in the desorbed gas flow is measured with a calorific mass flow meter, and the carbon dioxide concentration in the desorbed gas flow is detected with an infrared sensor. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent No. 10427086 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] As described above, the gas containing a high concentration of carbon dioxide (hereinafter referred to as "recovered gas") separated from the process gas containing a low concentration of carbon dioxide is either stored after recovery or used in the production of synthetic hydrocarbon fuels. Immediately after the desorption process of carbon dioxide from the adsorbent begins, the carbon dioxide concentration in the recovered gas is low because air present in the container is mixed with the recovered gas. The carbon dioxide concentration in the recovered gas gradually increases and eventually converges. Because the carbon dioxide concentration of the recovered gas fluctuates in this way, there is a need to measure the carbon dioxide concentration of the recovered gas. However, although carbon dioxide concentration analyzers using infrared sensors are known as in-line carbon dioxide concentration meters, these instruments are expensive and difficult to obtain.

[0006] This disclosure has been made in view of the above circumstances, and its purpose is to provide a technology for measuring the carbon dioxide concentration of a recovered gas containing carbon dioxide separated from a process gas, in a gas separation system that separates and recovers carbon dioxide from a process gas containing carbon dioxide, and which can reduce costs. [Means for solving the problem]

[0007] To solve the above problems, a gas separation system according to one aspect of this disclosure is: A recovery gas line through which recovery gas containing carbon dioxide, separated from a carbon dioxide-containing processing gas, flows. A recovery gas oxygen concentration meter is connected in-line to the recovery gas line and measures the oxygen concentration of the recovery gas in the recovery gas line. The system includes a carbon dioxide concentration calculator that calculates an estimated value of the carbon dioxide concentration of the recovered gas based on the oxygen concentration of the recovered gas measured by the recovered gas oxygen concentration meter.

[0008] Furthermore, the method for measuring the carbon dioxide concentration of a gas separation system according to one aspect of this disclosure is: In a gas separation system including a recovery gas line through which a recovery gas containing carbon dioxide separated from a process gas containing carbon dioxide flows, a method for measuring the carbon dioxide concentration of the recovery gas, comprising: measuring the oxygen concentration of the recovery gas flowing through the recovery gas line with an oxygen concentration meter, and obtaining an estimated value of the carbon dioxide concentration of the recovery gas based on the measured oxygen concentration of the recovery gas.

Advantages of the Invention

[0009] According to the present disclosure, there is provided a technique for measuring the carbon dioxide concentration of a recovery gas containing carbon dioxide separated from a process gas in a gas separation system that separates and recovers carbon dioxide from the process gas, which can suppress costs.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 is a schematic configuration diagram of a gas separation system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a functional block diagram of an arithmetic unit.

Embodiments for Carrying Out the Invention

[0011] Next, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a gas separation system 1 according to an embodiment of the present disclosure.

[0012] 《Configuration of Gas Separation System 1》 The gas separation system 1 shown in FIG. 1 is a system that separates carbon dioxide from a process gas containing carbon dioxide and recovers a recovered gas containing the separated carbon dioxide. The process gas may be any gas containing carbon dioxide, and examples include air in the atmosphere or air in a closed space. The carbon dioxide concentration of the recovered gas is sufficiently high compared to the carbon dioxide concentration of the process gas. The recovered gas containing high-concentration carbon dioxide is once recovered in the carbon dioxide holders 41 and 42, and then stored in a tank or underground, or used for the production of synthetic hydrocarbon fuel.

[0013] The gas separation system 1 includes a recovered gas line 15 through which the recovered gas flows. The gas separation system 1 may further include a processing container 2, a process gas supply line 12, a clean gas line 13, a steam supply line 14 connected to the processing container 2, and an arithmetic unit 6.

[0014] In the processing container 2, a process for separating carbon dioxide from the process gas is performed. In the gas separation system 1 according to the present embodiment, the processing container 2 is filled with an adsorbent 20 that selectively adsorbs carbon dioxide. The adsorbent 20 according to the present embodiment is a solid carbon dioxide adsorbent in which an amine compound that adsorbs carbon dioxide is supported on a porous body. Examples of the porous body include activated carbon and activated alumina. When this adsorbent 20 comes into contact with a gas containing carbon dioxide, it has the property of selectively adsorbing carbon dioxide contained in the gas. Further, the carbon dioxide adsorption characteristics of this adsorbent 20 depend on the temperature and the carbon dioxide partial pressure of the environment, and the adsorption and desorption of carbon dioxide can be repeated by a temperature or pressure swing. However, as the adsorbent 20, a carbon dioxide absorption liquid may be used instead of the solid carbon dioxide adsorbent.

[0015] Process gas is supplied from the process gas source to the process container 2 through the process gas supply line 12. The process gas supply line 12 includes piping connected to the inlet of the process container 2, a blower 22 that pressurizes the process gas into the process container 2, and an on / off valve 31 that switches between supplying and stopping the process gas. The process gas supply line 12 may further include a heater that raises the temperature of the process gas to a temperature suitable for adsorption by the adsorbent material 20, and a dehumidifier that dehumidifies the process gas to a humidity suitable for adsorption by the adsorbent material 20. Furthermore, the process gas supply line 12 may be equipped with a process gas oxygen concentration meter 25 that measures the oxygen concentration of the process gas flowing through the process gas supply line 12.

[0016] The clean gas line 13 is where the treated gas, from which carbon dioxide has been removed in the treatment container 2, i.e., the carbon dioxide clean gas, flows out. The clean gas line 13 includes piping connected to the outlet of the treatment container 2 and an on / off valve 34 that switches between discharging and stopping the discharge of the carbon dioxide clean gas.

[0017] Steam is supplied from the steam generator 24 to the processing vessel 2 through the steam supply line 14. The steam supply line 14 includes piping connected to the steam generator 24 and the steam inlet of the processing vessel 2, and an on / off valve 32 that switches between supplying and stopping the supply of steam.

[0018] The recovery gas line 15 carries the gas containing carbon dioxide separated from the processing gas in the processing container 2, i.e., the recovered gas. The recovery gas line 15 includes piping connected to the exhaust port of the processing container 2, an on-off valve 33 for switching between discharge and stopping the discharge of the recovered gas, a condenser 26, and an exhaust pump 23. The condenser 26 is located downstream of the on-off valve 33 and upstream of the exhaust pump 23 to remove moisture contained in the recovered gas by condensation. The recovery gas line 15 is equipped with a recovered gas oxygen concentration meter 4 for measuring the oxygen concentration of the recovered gas flowing through the recovery gas line 15. The recovered gas oxygen concentration meter 4 is located downstream of the exhaust pump 23.

[0019] The recovery gas line 15 may be divided into multiple flow paths downstream of the recovery gas oxygen concentration meter 4. In this embodiment, the recovery gas line 15 is divided into a flow path leading to the first carbon dioxide holder 41 and a flow path leading to the second carbon dioxide holder 42, and a flow path switching valve 43 is provided at this branching point. The flow path switching valve 43 switches the flow path of the recovery gas line 15 so that one of the multiple branched flow paths is connected to the processing container 2. This makes it possible to switch the destination of the recovered gas between the first carbon dioxide holder 41 and the second carbon dioxide holder 42. However, the recovery gas line 15 may be divided into three or more flow paths.

[0020] The processing gas oxygen concentration meter 25 is an oxygen concentration meter that can be connected in-line to the processing gas supply line 12. Similarly, the recovery gas oxygen concentration meter 4 is an oxygen concentration meter that can be connected in-line to the recovery gas line 15. For example, a zirconia type oxygen concentration meter or a galvanic cell type oxygen concentration meter can be used as the processing gas oxygen concentration meter 25 and the recovery gas oxygen concentration meter 4.

[0021] The computing unit 6 is electrically connected by wired or wireless means to the processed gas oxygen concentration meter 25 and the recovered gas oxygen concentration meter 4, and acquires the oxygen concentration measured by these instruments 25 and 4. The computing unit 6 is electrically connected by wired or wireless means to the on-off valves 31, 32, 33, and 34, and controls the operation of the on-off valves 31, 32, 33, and 34. The computing unit 6 is electrically connected by wired or wireless means to the flow path switching valve 43, and controls the operation of the flow path switching valve 43. Furthermore, the computing unit 6 is electrically connected by wired or wireless means to the steam generator 24, and controls the operation of the steam generator 24. The computing unit 6 can be realized, for example, as a computer equipped with a CPU (Central Processing Unit), memory, an auxiliary storage device such as an HDD (Hard Disk Drive), a communication I / F for connecting to a communication network or other devices by wired or wireless means, input devices such as a mouse, keyboard, touch sensor or touch panel, and output devices such as a liquid crystal display.

[0022] Figure 2 is a functional block diagram of the arithmetic unit 6. As shown in Figure 2, the arithmetic unit 6 has the following functional units: a carbon dioxide concentration calculator 61, a flow path switching valve controller 62, and a steam amount controller 63. The carbon dioxide concentration calculator 61 calculates an estimated value of the carbon dioxide concentration of the recovered gas based on information obtained from the processing gas oxygen concentration meter 25 and the recovered gas oxygen concentration meter 4. The flow path switching valve controller 62 switches the flow path of the recovered gas line 15 by operating the flow path switching valve 43. The steam amount controller 63 adjusts the amount of steam supplied to the processing container 2 through the steam supply line 14 by operating the steam generation amount of the steam generator 24. Each functional unit of the arithmetic unit 6 can be realized by loading a predetermined program stored in the auxiliary storage device into memory and executing it with the CPU.

[0023] Gas separation method Here, a gas separation method using the gas separation system 1 configured as described above will be explained. The gas separation method includes a separation step for separating carbon dioxide from the process gas and a recovery step for recovering the carbon dioxide separated from the process gas. In this embodiment, in the separation step, an adsorption process is performed to separate carbon dioxide from the process gas by bringing the adsorbent 20 into contact with the process gas and adsorbing carbon dioxide onto the adsorbent 20. In the recovery step, a desorption process is performed to desorb carbon dioxide from the adsorbent 20 by bringing the adsorbent 20, which has adsorbed carbon dioxide, into contact with water vapor.

[0024] First, in the separation process, with valves 31 and 34 open and valves 32 and 33 closed, the blower 22 operates to supply the processed gas to the processing container 2 through the processing gas supply line 12. The flow of the processed gas inside the processing container 2 comes into contact with the adsorbent 20, and the carbon dioxide contained in the processed gas is adsorbed by the adsorbent 20, separating the carbon dioxide from the processed gas. The processed gas from which carbon dioxide has been removed, i.e., the carbon dioxide clean gas, is discharged from the processing container 2 to the clean gas line 13.

[0025] In the recovery process, with the on-off valves 31 and 34 closed and the on-off valves 32 and 33 open, by operating the exhaust pump 23 and the steam generator 24, water vapor is supplied to the processing vessel 2 through the steam supply line 14, and the inside of the processing vessel 2 is forcibly exhausted to the recovery gas line 15. The carbon dioxide partial pressure of the water vapor contacting the adsorbent 20 is significantly lower than the carbon dioxide partial pressure on the surface of the adsorbent 20, and this difference in carbon dioxide partial pressure serves as the driving force, causing the carbon dioxide adsorbed on the adsorbent 20 to diffuse into the water vapor. In this way, the adsorbent 20 is regenerated by the desorption of carbon dioxide from the adsorbent 20. The recovery gas containing carbon dioxide and water vapor desorbed from the adsorbent 20 is forcibly exhausted from the processing vessel 2 to the recovery gas line 15. In the recovery gas line 15, the moisture contained in the recovery gas is removed by the condenser 81, and the recovery gas from which the moisture has been removed is compressed by the exhaust pump 23 and then sent to the carbon dioxide holders 41 and 42 and recovered in the carbon dioxide holders 41 and 42.

[0026] The oxygen concentration of the recovery gas sent to the carbon dioxide holders 41 and 42 is measured by the recovery gas oxygen concentration meter 4. Also, the oxygen concentration of the processing gas supplied to the processing vessel 2 is measured by the processing gas oxygen concentration meter 25. The arithmetic unit 6 acquires the oxygen concentration of the processing gas detected by the processing gas oxygen concentration meter 25 and the oxygen concentration of the recovery gas detected by the recovery gas oxygen concentration meter 4. The carbon dioxide concentration calculator 61 of the arithmetic unit 6 estimates the carbon dioxide concentration of the recovery gas using the acquired oxygen gas concentration. The carbon dioxide concentration of the recovery gas is the carbon dioxide concentration C

[0027] , , of the recovery gas, the oxygen concentration P O2 of the processing gas, and the oxygen concentration C O2 of the recovery gas, and is expressed by the following formula 1. Note that the carbon dioxide concentration C CO2 of the recovery gas, the oxygen concentration P O2 of the processing gas, and the oxygen concentration C O2 of the recovery gas may be either a mass fraction or a volume fraction. [Formula 1] C CO2 = 1 - C O2 / P O2

[0027] Equation 1 may further include a correction term k for the carbon dioxide concentration in the air. In this case, the carbon dioxide concentration of the recovered gas is expressed as r. [Formula 2]C CO2 = 1-C O2 / P O2 +k

[0028] Furthermore, Equation 1 may include a correction coefficient f to improve the accuracy of the calculation formula. In this case, the carbon dioxide concentration of the recovered gas is expressed by Equation 3. [Formula 3]C CO2 =f(1-C O2 / P O2 ) The correction factor f is the oxygen concentration C of the recovered gas. O2 This is a function of . For example, the carbon dioxide concentration calculated using Equation 1 is compared with the carbon dioxide concentration measured experimentally beforehand, and the correction coefficient f is determined so that the calculated carbon dioxide concentration approaches the measured carbon dioxide concentration.

[0029] For example, if the process gas is air, the mass fraction of oxygen in the process gas is approximately 0.21 and the volume fraction is approximately 0.23. In this case, the carbon dioxide concentration C of the recovered gas calculated using Equation 1 is... CO2 This is expressed as a mass fraction (1-x / 0.21) and as a volume fraction (1-x / 0.23).

[0030] If the oxygen concentration of the process gas is known, then the oxygen concentration P of the process gas O2 A predetermined value is used as the value. Furthermore, if the oxygen concentration of the processed gas fluctuates, the value detected by the processed gas oxygen concentration meter 25 is used as the oxygen concentration P of the processed gas. O2 It is used as such.

[0031] As described above, the computing device 6 calculates and stores an estimated value of the carbon dioxide concentration of the recovered gas using the oxygen concentration of the recovered gas detected during the operation of the gas separation system 1, or the oxygen concentrations of the recovered gas and the processed gas detected.

[0032] Furthermore, the calculation unit 6 may be configured to perform a switching operation of the flow path switching valve 43 using the carbon dioxide concentration of the recovered gas determined. For example, the flow path switching valve controller 62 of the calculation unit 6 is configured to switch the flow path of the recovery gas line 15 using the flow path switching valve 43 so that if the carbon dioxide concentration of the recovered gas is below a predetermined threshold, the recovered gas is sent to the first carbon dioxide holder 41, and if the carbon dioxide concentration of the recovered gas is above a predetermined threshold, the recovered gas is sent to the second carbon dioxide holder 42. This allows for the recovery of high-concentration carbon dioxide in the second carbon dioxide holder 42.

[0033] Furthermore, the calculation unit 6 may be configured to adjust the steam generation rate of the steam generator 24 using the calculated carbon dioxide concentration of the recovered gas. The carbon dioxide concentration of the recovered gas gradually increases after the start of the recovery process and eventually converges to a nearly constant value. If the converged value of the carbon dioxide concentration of the recovered gas falls below a predetermined target value, it is presumed that gas is entering the processing container 2 from the outside. Therefore, the steam amount controller 63 of the calculation unit 6 increases the steam generation rate of the steam generator 24 from the steady value when the converged value of the carbon dioxide concentration of the recovered gas falls below a predetermined target value. The steam generator 24 can increase or decrease the steam generation rate in a stepwise or continuous manner, and the amount of increase when increasing the steam generation rate may be set in advance in the calculation unit 6. By increasing the amount of steam supplied to the processing container 2, the internal pressure of the processing container 2 increases, suppressing the intrusion of external gas into the processing container 2, and as a result, the converged value of the carbon dioxide concentration of the recovered gas can be increased. Once the converged value of the carbon dioxide concentration of the recovered gas reaches the predetermined target value, the steam generation rate of the steam generator 24 may be returned to the low normal value.

[0034] [Variation] In the gas separation system 1 according to the above embodiment, an adsorbent 20 is used in the processing container 2 to separate carbon dioxide from the processing gas. However, the method of separating carbon dioxide from the processing gas is not limited to the above embodiment. For example, the processing container 2 may be equipped with a carbon dioxide permeable membrane that selectively permeates carbon dioxide, and configured to separate carbon dioxide from the processing gas using the carbon dioxide permeable membrane. In this case, the gas that permeates through the carbon dioxide permeable membrane is the "recovered gas" that flows from the processing container 2 to the recovery gas line 15, and the gas that does not permeate through the carbon dioxide permeable membrane is the "carbon dioxide clean gas" that flows to the clean gas line 13.

[0035] [Summary] The gas separation system 1 relating to item 1 of this disclosure is A recovery gas line 15 through which recovery gas containing carbon dioxide, separated from the carbon dioxide-containing treatment gas, A recovery gas oxygen concentration meter 4 is connected in-line to the recovery gas line 15 and measures the oxygen concentration of the recovery gas in the recovery gas line 15, The system includes a carbon dioxide concentration calculator 61 that calculates an estimated value of the carbon dioxide concentration of the recovered gas based on the oxygen concentration of the recovered gas measured by the recovered gas oxygen concentration meter 4.

[0036] In the gas separation system 1 with the above configuration, instead of directly measuring or analyzing the carbon dioxide concentration of the recovered gas, the oxygen concentration of the recovered gas is measured, and the carbon dioxide concentration of the recovered gas is calculated based on the measured oxygen concentration. Generally speaking, oxygen concentration meters such as zirconia oxygen concentration meters and galvanic cell oxygen concentration meters are less expensive and readily available compared to carbon dioxide concentration analyzers using infrared sensors. Therefore, according to this disclosure, it is possible to provide a technology for measuring the carbon dioxide concentration of recovered gas containing carbon dioxide separated from a processed gas that can reduce costs.

[0037] The gas separation system 1 relating to the second item of this disclosure further comprises a processing vessel 2 from which carbon dioxide is separated from the processing gas, a processing gas supply line 12 connected to the processing vessel 2 and supplying the processing gas to the processing vessel 2, and a processing gas oxygen concentration meter 25 connected inline to the processing gas supply line 12 and measuring the oxygen concentration of the processing gas in the processing gas supply line 12. The carbon dioxide concentration calculator 61 determines an estimated value of the carbon dioxide concentration of the recovered gas based on the oxygen concentration of the processing gas measured by the processing gas oxygen concentration meter 25 and the oxygen concentration of the recovered gas measured by the recovered gas oxygen concentration meter 4.

[0038] In the gas separation system 1 with the above configuration, the measured oxygen concentration of the processed gas and the measured oxygen concentration of the recovered gas are used to calculate the carbon dioxide concentration of the recovered gas. Therefore, even if the oxygen concentration of the processed gas is not a known or fixed value, the carbon dioxide concentration of the recovered gas can be determined.

[0039] The gas separation system 1 relating to item 3 of this disclosure is, in the gas separation system 1 relating to item 1 or 2, the carbon dioxide concentration calculator 61 is C CO2 The carbon dioxide concentration of the recovered gas, P O2 The oxygen concentration of the processed gas, C O2 The oxygen concentration of the recovered gas is taken as , and the carbon dioxide concentration of the recovered gas is calculated using the following equation 1. [Formula 1]C CO2 = 1-C O2 / P O2

[0040] This allows us to determine the mass fraction or volume fraction of the carbon dioxide concentration in the recovered gas.

[0041] The gas separation system 1 relating to the fourth item of this disclosure is a gas separation system 1 relating to any of the first to third items, wherein the recovered gas line 15 includes a plurality of flow paths and a flow path switching valve 43 that switches the flow path of the recovered gas line 15 so that the recovered gas flows into one of the plurality of flow paths, and further comprises a flow path switching valve controller 62 that switches the flow path switching valve 43 based on an estimated value of the carbon dioxide concentration of the recovered gas calculated by a carbon dioxide concentration calculator 61.

[0042] This allows the destination of the recovered gas to be changed depending on the carbon dioxide concentration of the recovered gas.

[0043] The gas separation system 1 according to item 5 of this disclosure further comprises, in the gas separation system 1 according to any one of items 1 to 4, a processing container filled with a carbon dioxide adsorbent 20 having an amine compound that adsorbs carbon dioxide supported on a porous body, and from which carbon dioxide is separated from the processing gas; a steam supply line 14 connected to the processing container 2 that supplies steam to the processing container 2 to desorb carbon dioxide from the carbon dioxide adsorbent 20; and a steam amount controller 63 that adjusts the amount of steam supplied to the processing container 2 through the steam supply line 14 based on an estimated value of the carbon dioxide concentration of the recovered gas calculated by a carbon dioxide concentration calculator 61.

[0044] This allows the amount of steam supplied to the processing container 2 for carbon dioxide desorption to be increased or decreased depending on the carbon dioxide concentration of the recovered gas. For example, if the convergence value of the carbon dioxide concentration of the recovered gas falls below a predetermined target value, the amount of steam supplied to the processing container 2 is increased by increasing the steam generation rate of the steam generator 24 or by widening the opening of the on-off valve 32.

[0045] The method for measuring carbon dioxide in a gas separation system 1 relating to item 6 of this disclosure is a method for measuring the carbon dioxide concentration of a recovered gas in a gas separation system 1 that includes a recovered gas line 15 through which a recovered gas containing carbon dioxide separated from a processed gas containing carbon dioxide flows, The oxygen concentration of the recovered gas flowing through the recovered gas line 15 is measured using the oxygen concentration meter 4, and, This includes estimating the carbon dioxide concentration of the recovered gas based on the measured oxygen concentration of the recovered gas.

[0046] In the carbon dioxide measurement method of the gas separation system 1 described above, instead of directly measuring or analyzing the carbon dioxide concentration of the recovered gas, the oxygen concentration of the recovered gas is measured, and the carbon dioxide concentration of the recovered gas is calculated based on the measured oxygen concentration. Generally speaking, oxygen concentration meters such as zirconia oxygen concentration meters and galvanic cell oxygen concentration meters are inexpensive and readily available compared to carbon dioxide concentration analyzers using infrared sensors. Therefore, according to this disclosure, it is possible to provide a technology for measuring the carbon dioxide concentration of recovered gas containing carbon dioxide separated from a processed gas that can reduce costs.

[0047] The functions realized by the arithmetic unit 6 described herein may be implemented in a circuit or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to realize the described functions. A processor, including transistors and other circuits, is considered a circuit or processing circuitry. A processor may be a programmed processor that executes a program stored in memory. In this specification, circuitry, unit, and means are hardware programmed to realize or perform the described functions. Such hardware may be any hardware disclosed herein, or any hardware known to be programmed to realize or perform the described functions. If such hardware is a processor that is considered a type of circuitry, then such circuitry, means, or unit is a combination of hardware and software used to constitute such hardware and / or processor.

[0048] The embodiments described above are presented for illustrative and explanatory purposes only and are not intended to limit the disclosure to the forms disclosed herein. For example, in the detailed description above, various features of the disclosure are grouped into one embodiment for the purpose of streamlining the disclosure, but some of the features may be combined. Also, some of the features included in the disclosure may be combined into alternative embodiments, configurations, or aspects other than those discussed above. [Explanation of Symbols]

[0049] 1: Gas separation system 2: Processing container 4: Oxygen concentration meter 4: Recovery gas oxygen concentration meter 12: Processing gas supply line 14: Steam supply line 15: Recovery gas line 20: Adsorbent 20: Carbon dioxide adsorbent 24: Steam generator 25: Oxygen concentration meter for processed gases 43: Flow path switching valve 61: Carbon dioxide concentration calculator 62: Flow path switching valve controller 63: Steam volume controller

Claims

1. A recovery gas line through which recovery gas containing carbon dioxide, separated from a carbon dioxide-containing processing gas, flows. A recovery gas oxygen concentration meter is connected in-line to the recovery gas line and measures the oxygen concentration of the recovery gas in the recovery gas line. The system includes a carbon dioxide concentration calculator that calculates an estimated value of the carbon dioxide concentration of the recovered gas based on the oxygen concentration of the recovered gas measured by the recovered gas oxygen concentration meter, and Gas separation system.

2. A processing vessel from which carbon dioxide is separated from the aforementioned processing gas, A processing gas supply line connected to the processing container and supplying the processing gas to the processing container, The system further includes a process gas oxygen concentration meter connected in-line to the process gas supply line for measuring the oxygen concentration of the process gas in the process gas supply line, The carbon dioxide concentration calculator calculates an estimated value of the carbon dioxide concentration of the recovered gas based on the oxygen concentration of the processed gas measured by the processed gas oxygen concentration meter and the oxygen concentration of the recovered gas measured by the recovered gas oxygen concentration meter. The gas separation system according to claim 1.

3. The carbon dioxide concentration calculator is C CO2 The carbon dioxide concentration of the recovered gas, P O2 The oxygen concentration of the processing gas, C O2 Let the oxygen concentration of the recovered gas be given by the following equation 1, and then calculate the carbon dioxide concentration of the recovered gas. The gas separation system according to claim 1 or 2. [Equation 1] C CO2 =1-C O2 / P O2

4. The recovery gas line includes a plurality of flow paths and a flow path switching valve that switches the flow path of the recovery gas line so that the recovery gas flows into one of the plurality of flow paths. The system further includes a flow path switching valve controller that switches the flow path switching valve based on the estimated carbon dioxide concentration of the recovered gas calculated by the carbon dioxide concentration calculator. The gas separation system according to claim 1.

5. A processing container is filled with a carbon dioxide adsorbent in which an amine compound that adsorbs carbon dioxide is supported on a porous body, and carbon dioxide is separated from the processing gas. A steam supply line connected to the processing container supplies steam to the processing container to desorb carbon dioxide from the carbon dioxide adsorbent, The system further includes a steam volume controller that adjusts the amount of steam supplied to the processing container through the steam supply line based on an estimated carbon dioxide concentration of the recovered gas calculated by the carbon dioxide concentration calculator. The gas separation system according to claim 1.

6. A gas separation system comprising a recovery gas line through which a carbon dioxide-containing recovery gas separated from a carbon dioxide-containing treatment gas flows, a method for measuring the carbon dioxide concentration of the recovery gas, Measure the oxygen concentration of the recovered gas flowing through the recovered gas line using an oxygen concentration meter, and This includes determining an estimated value of the carbon dioxide concentration of the recovered gas based on the measured oxygen concentration of the recovered gas, A method for measuring carbon dioxide concentration in a gas separation system.

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