Recovery device, recovery method, and computer program

Abstract

To provide a technique for stabilizing the quality of recovery gas in a recovery device.SOLUTION: A recovery device comprises: an adsorber which stores an adsorbent that adsorbs a specific material; an acquisition unit which acquires mixed gas information being estimation information or measurement information of a property of mixed gas including the temperature of the mixed gas and supplied to the adsorber, and an adsorption condition being estimation information or measurement information of an environmental condition affecting the adsorption performance of the adsorbent including the environmental temperature of the adsorbent; an estimation unit which estimates an adsorption amount estimation value of the adsorbent and a saturation adsorption amount of the adsorbent by using the mixed gas information and the adsorption condition; and a switching unit which switches the adsorber supplying the mixed gas according to the estimated adsorption amount estimation value and saturation adsorption amount.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a recovery device, a recovery method, and a computer program. [Background technology]

[0002] Conventionally, recovery devices that recover specific substances contained in mixed gases have been known (for example, Patent Documents 1 and 2). The recovery device recovers the specific substance by, for example, adsorbing the specific substance in the mixed gas using an adsorbent in an adsorption step, and desorbing the specific substance adsorbed by the adsorbent from the adsorbent in a recovery step. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6791177 specification [Patent Document 2] Japanese Patent Application Publication No. 2020-78860 Summary of the Invention [Problem to be solved by the invention]

[0004] When specific substances recovered by a recovery device are used in the manufacture of industrial products, etc., stable concentration of the specific substance in the recovered gas containing the specific substance desorbed from the adsorbent is required to consistently produce products of consistent quality. However, the amount of specific substance that an adsorbent can adsorb varies depending on the properties of the mixed gas and the environment in which the adsorbent is placed, so the amount of specific substance desorbed from the adsorbent may vary for each recovery process. In this case, the concentration of the specific substance in the recovered gas also changes, making it difficult to stabilize the quality of the recovered gas.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a technique for stabilizing the quality of recovered gas in a recovery device. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0007] (1) According to one aspect of the present invention, there is provided a recovery device for recovering a specific substance contained in a mixed gas. The recovery device includes an adsorber containing an adsorbent that adsorbs the specific substance, an acquisition unit that acquires mixed gas information, which is estimated or measured information on properties of the mixed gas supplied to the adsorber, including the temperature of the mixed gas, and adsorption conditions, which is estimated or measured information on environmental conditions that affect the adsorption performance of the adsorbent, including the ambient temperature of the adsorbent, an estimation unit that estimates an adsorption amount estimate of the adsorbent and a saturated adsorption amount of the adsorbent using the mixed gas information and the adsorption conditions, and a switching unit that switches the adsorber to which the mixed gas is supplied, based on the estimated adsorption amount estimate and the saturated adsorption amount.

[0008] According to this configuration, the switching unit switches the adsorber to which the mixed gas is supplied in accordance with the adsorption amount estimate of the adsorbent and the saturated adsorption amount, which are estimated using the mixed gas information including the temperature of the mixed gas and the adsorption conditions including the ambient temperature of the adsorbent. The saturated adsorption amount of the adsorbent is influenced by the properties of the mixed gas supplied to the adsorber and the environmental conditions that affect the adsorption performance of the adsorbent, so the saturated adsorption amount estimated in this manner is a value that is more appropriate to the actual situation than, for example, a saturated adsorption amount that is fixed as a set value. Thus, by switching the supply destination of the mixed gas in accordance with the adsorption amount estimate of the adsorbent and the saturated adsorption amount estimated by the estimation unit, it is possible to prevent the specific substance from being released outside the system. Therefore, when the specific substance adsorbed to the adsorbent is recovered, the concentration of the specific substance in the recovered gas can be kept constant, thereby stabilizing the quality of the recovered gas.

[0009] (2) In the recovery apparatus of the above aspect, the estimation unit may use the mixed gas information to estimate an estimated amount of the specific substance introduced into the adsorber, use the estimated amount to estimate an estimated adsorption amount representing the amount of the specific substance adsorbed by the adsorbent at a specific time, and calculate a switching threshold by multiplying the saturated adsorption amount estimated using the mixed gas information by a control constant. The switching unit may compare the estimated adsorption amount with the switching threshold to switch the adsorber to which the mixed gas is supplied. According to this configuration, the switching unit estimates an estimated adsorption amount representing the amount of the specific substance adsorbed by the adsorbent at a specific time based on the estimated amount of the specific substance introduced into the adsorber, and compares the estimated estimated adsorption amount with the switching threshold calculated by multiplying the saturated adsorption amount by the control constant. The switching unit switches the adsorber to which the mixed gas is supplied based on the comparison result. That is, the destination of the mixed gas is switched by comparing the estimated adsorption amount, estimated using only the mixed gas information, with the switching threshold. This allows for easy stabilization of the quality of the recovered gas.

[0010] (3) In the recovery apparatus of the above aspect, the acquisition unit may acquire exhaust gas information, which is estimated or measured information on the properties of the exhaust gas, including the flow rate of the exhaust gas discharged from the adsorber and the concentration of the specific substance in the exhaust gas. The estimation unit may use the mixed gas information to estimate an introduction amount of the specific substance to be introduced into the adsorber, use the exhaust gas information to estimate an emission amount of the specific substance discharged from the adsorber, and use the difference between the introduction amount estimate and the emission amount estimate to estimate the adsorption amount estimate representing the amount of the specific substance adsorbed by the adsorbent at a specific time. The switching unit may compare the adsorption amount estimate with the switching threshold to switch the adsorber to which the mixed gas is supplied. According to this configuration, the estimation unit estimates the adsorption amount estimate using the difference between the introduction amount estimate of the specific substance to be introduced into the adsorber and the emission amount estimate of the specific substance discharged from the adsorber. The switching unit switches the adsorber to which the mixed gas is supplied by comparing the estimated adsorption amount with a switching threshold. This improves the accuracy of the estimated adsorption amount compared to when the estimated adsorption amount is estimated only from the estimated amount of the specific substance introduced into the adsorber. Therefore, the switching unit can accurately switch the supply destination of the mixed gas, further stabilizing the quality of the recovered gas.

[0011] (4) In the recovery device of the above aspect, the acquisition unit may acquire desorption amount information, which is estimated or measured information on the desorption amount of the specific substance desorbed from the adsorbent that has adsorbed the specific substance, and the estimation unit may use the desorption amount information to estimate a desorption amount estimate and calculate the control constant using a ratio of the desorption amount estimate to the introduction amount estimate. According to this configuration, the estimation unit calculates the control constant using the ratio of the desorption amount estimate to the introduction amount estimate, i.e., the recovery rate of the specific substance. This stabilizes the recovery rate of the specific substance, which is one of the qualities of the recovered gas, thereby further stabilizing the quality of the recovered gas.

[0012] (5) In the recovery device of the above aspect, the estimation unit may use the mixed gas information to calculate an average value of the properties of the mixed gas from the start of supplying the mixed gas to the adsorber to the specific time point, use the adsorption conditions to calculate an average value of the environmental conditions from the start of supplying the mixed gas to the adsorber to the specific time point, and estimate the saturated adsorption amount of the adsorbent using the average value of the properties of the mixed gas and the average value of the environmental conditions. According to this configuration, the saturated adsorption amount of the adsorbent is estimated using the average value of the properties of the mixed gas and the average value of the environmental conditions from the start of supplying the mixed gas to the adsorber to the specific time point. Even if there is a sudden change in the properties of the mixed gas or environmental conditions after the supply of the mixed gas to the vessel begins, the saturated adsorption amount of the adsorbent can be estimated, making it possible to stabilize the quality of the recovered gas.

[0013] (6) In the recovery device of the above aspect, the acquisition unit may acquire the mixed gas information including the concentration of a substance other than the specific substance contained in the mixed gas, and the estimation unit may estimate the saturated adsorption amount of the adsorbent using the concentration of the gas other than the specific substance contained in the mixed gas, which is included in the mixed gas information. According to this configuration, the acquisition unit acquires the mixed gas information including the concentration of the substance other than the specific substance contained in the mixed gas. Because the adsorbent also adsorbs substances other than the specific substance, the saturated adsorption amount of the adsorbent decreases. By estimating the saturated adsorption amount using the concentration of the substance other than the specific substance, the estimation accuracy of the saturated adsorption amount can be improved.

[0014] (7) According to another aspect of the present invention, a recovery method for recovering a specific substance contained in a mixed gas using a recovery device is provided. The recovery method includes the steps of: adsorbing the specific substance onto an adsorbent; acquiring mixed gas information, which is estimated or measured information on the properties of the mixed gas supplied to an adsorber, including the temperature of the mixed gas; and adsorption conditions, which is estimated or measured information on environmental conditions that affect the adsorption performance of the adsorbent, including the ambient temperature of the adsorbent; estimating an adsorption amount estimate of the adsorbent and a saturated adsorption amount of the adsorbent using the mixed gas information and the adsorption conditions; and switching the adsorbent to supply the mixed gas in accordance with the estimated adsorption amount estimate and the saturated adsorption amount. According to this configuration, the recovery device switches the adsorbent to supply the mixed gas in accordance with the saturated adsorption amount of the adsorbent estimated using the mixed gas information, including the temperature of the mixed gas, and the adsorption conditions, including the ambient temperature of the adsorbent. This stabilizes the proportion of adsorbent used to adsorb the specific substance, thereby stabilizing the quality of the recovered gas.

[0015] (8) According to yet another aspect of the present invention, a computer program is provided that causes a computer to execute a recovery of a specific substance contained in a mixed gas. The computer program causes the computer to perform the following functions: adsorbing the specific substance onto an adsorbent; acquiring mixed gas information, which is estimated or measured information on the properties of the mixed gas supplied to an adsorber containing the adsorbent, including the temperature of the mixed gas; and adsorption conditions, which are estimated or measured information on environmental conditions that affect the adsorption performance of the adsorbent, including the ambient temperature of the adsorbent; estimating an adsorption amount estimate of the adsorbent and a saturated adsorption amount of the adsorbent using the mixed gas information and the adsorption conditions; and switching the adsorber to which the mixed gas is supplied in accordance with the estimated adsorption amount estimate and the saturated adsorption amount. According to this configuration, the computer switches the adsorber to which the mixed gas is supplied in accordance with the saturated adsorption amount of the adsorbent estimated using the mixed gas information, including the temperature of the mixed gas, and the adsorption conditions, including the ambient temperature of the adsorbent. This stabilizes the proportion of adsorbent used to adsorb the specific substance, thereby stabilizing the quality of the recovered gas.

[0016] The present invention can be realized in various forms, such as a system including a collection device, a control method including a collection method using these devices and systems, a server device for distributing a computer program, and a non-transitory storage medium on which the computer program is stored. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a recovery device according to a first embodiment. [Figure 2] 10 is a flowchart illustrating a collection method by the collection system. [Figure 3] FIG. 10 is a diagram illustrating a set utilization rate of an adsorbent. [Figure 4] FIG. 1 is a diagram illustrating the change over time in the amount of CO2 adsorption in the recovery method. [Figure 5] FIG. 4 is a diagram showing the change in the properties of a mixed gas over time. [Figure 6] FIG. 4 is a diagram illustrating the relationship between the utilization rate of the adsorbent and the quality of the recovered gas. [Figure 7] FIG. 10 is a diagram illustrating the change in the average CO2 concentration during the adsorption process and the duration of the adsorption process. [Figure 8] FIG. 1 is a first diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. [Figure 9] FIG. 2 is a second diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. [Figure 10] FIG. 10 is a diagram illustrating the influence of changes in the ambient temperature on the adsorbent. [Figure 11] FIG. 3 is a third diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. [Figure 12] FIG. 4 is a fourth diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. [Figure 13] FIG. 5 is a fifth diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. [Figure 14] FIG. 10 is a schematic diagram showing a schematic configuration of a recovery device according to a second embodiment. [Figure 15] FIG. 10 is a diagram illustrating the influence of changes in the impurity concentration of the adsorbent. [Figure 16] FIG. 10 is a schematic diagram showing a schematic configuration of a recovery device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] First Embodiment Fig. 1 is a schematic diagram showing the general configuration of a recovery apparatus according to a first embodiment. The recovery apparatus 1 according to the first embodiment is applied to a recovery system 5 including a plurality of adsorbers shown in Fig. 1. The recovery system 5 recovers carbon dioxide (CO2) from a mixed gas containing oxygen (O2), nitrogen (N2), moisture (H2O), etc., which is discharged from a combustion facility 6, and supplies the recovered carbon dioxide to a hydrocarbon synthesis unit 7. The recovery system 5 according to this embodiment includes three adsorbers 10, a mixed gas supply flow path 20, an exhaust gas flow path 30, a hydrogen gas supply flow path 40, a recovered gas flow path 50, a heat medium flow path 60, and a control unit 70.

[0019] The adsorber 10 is a device for separating and recovering CO2 from a mixed gas. The adsorber 10 accommodates an adsorbent 11 therein. The adsorbent 11 is, for example, zeolite, activated carbon, or silica gel, and has CO2 absorption (adsorption) performance. When a mixed gas containing CO2 is supplied to the adsorber 10, the CO2 is absorbed into the adsorbent 11, and the remaining components of the mixed gas are discharged to the outside of the adsorber 10. A mixed gas supply flow path 20, a hydrogen gas supply flow path 40, a recovered gas flow path 50, and a heat medium flow path 60 are connected to the adsorber 10. In this embodiment, for the sake of convenience, the three adsorbers 10 are referred to as adsorbers 10A, 10B, and 10C, which accommodate adsorbents 11A, 11B, and 11C, respectively, in order to distinguish them from one another (see FIG. 1). In addition, in Figure 1, the mixed gas supply flow path 20, exhaust gas flow path 30, hydrogen gas supply flow path 40, and recovered gas flow path 50, which are connected to the adsorber 10A during the adsorption process, the adsorber 10B during the recovery process, and the adsorber 10C during the cooling process, respectively, in the recovery method described below, are shown with solid lines indicating the flow paths through which gas is flowing and with dotted lines indicating the flow paths through which gas is not flowing.

[0020] The mixed gas supply flow path 20 is a gas flow path for supplying the mixed gas (indicated by the arrow Gex in FIG. 1 ) discharged from the combustion equipment 6 to each of the three adsorbers 10, and is composed of multiple gas pipes. Multiple mixed gas supply valves 21 and 22 are provided in the mixed gas supply flow path 20. The combustion equipment 6 is, for example, a combustion furnace in a factory, and the mixed gas contains O2, N2, HO, and the like in addition to CO2, as described above. The mixed gas discharged from the combustion equipment 6 passes through the mixed gas supply valve 21 and heads toward the adsorber 10A or the mixed gas supply valve 22. The mixed gas headed toward the mixed gas supply valve 22 passes through the mixed gas supply valve 22 and heads toward the adsorber 10B or the adsorber 10C. The opening and closing of each of the mixed gas supply valves 21 and 22 is controlled by a control unit 70.

[0021] The exhaust gas flow path 30 is a gas flow path for discharging the remaining gas (exhaust gas, arrow Gm shown in FIG. 1) after removing CO2 from the mixed gas from each of the three adsorbers 10, and is composed of multiple gas pipes. Multiple exhaust gas valves 31 and 32 are provided in the exhaust gas flow path 30. The exhaust gas discharged from the adsorbers 10A and 10B is The exhaust gas is discharged from the recovery system 5 via the valves 31 and 32. The exhaust gas discharged from the adsorber 10C is discharged from the recovery system 5 via the exhaust gas valve 32. The opening and closing of each of the exhaust gas valves 31 and 32 is controlled by the control unit 70.

[0022] The hydrogen gas supply flow path 40 is a gas flow path for supplying hydrogen (H2, indicated by arrow Gh in FIG. 1) from a hydrogen supply source (not shown) to each of the three adsorbers 10, and is composed of multiple gas pipes. Multiple hydrogen supply valves 41 and 42 are provided in the hydrogen gas supply flow path 40. H2 supplied from the hydrogen supply source passes through the hydrogen supply valve 41 and heads toward the adsorber 10C or the hydrogen supply valve 42. H2 headed toward the hydrogen supply valve 42 passes through the hydrogen supply valve 42 and heads toward the adsorber 10B or the adsorber 10A. The opening and closing of each of the hydrogen supply valves 41 and 42 is controlled by the control unit 70.

[0023] The recovered gas flow path 50 is a gas flow path for supplying the recovered gas (indicated by arrow Gch in FIG. 1 ) containing CO2 extracted from each of the three adsorbers 10 to the hydrocarbon synthesis system 7, and is configured to include multiple gas pipes. The recovered gas flow path 50 is provided with a recovered gas valve 51. The opening and closing of the recovered gas valve 51 is controlled by the control unit 70, and the recovered gas extracted from one of the three adsorbers 10 is supplied to the hydrocarbon synthesis system 7. The recovered gas flow path 50 is provided with a pump 52 that reduces the pressure inside the adsorber 10 via the recovered gas flow path 50. This makes it easier for CO2 to be desorbed from the adsorbent 11.

[0024] The heat medium flow path 60 is a flow path through which a heat medium (thermal fluid) such as oil flows, and supplies heat generated in the hydrocarbon synthesis unit 7 by a production reaction of hydrocarbon compounds such as methane (CH4) to the three adsorbers 10. The heat medium supplied to the adsorbers 10 heats the adsorbent 11, and then returns to the hydrocarbon synthesis unit 7 to be heated again. By repeating this process, CO2 is easily desorbed from the adsorbent 11. In FIG. 1, to avoid complication of the drawing, the heat medium flow path 60 is connected to the hydrocarbon synthesis unit 7 and the adsorber 10B in the recovery step, but the heat medium flow path 60 is also connected to the adsorbers 10A and 10C in the same way.

[0025] The control unit 70 includes a computer configured with a ROM, a RAM, and a CPU, and controls the entire recovery system 5 based on the properties of the mixed gas and the environmental conditions of the adsorber 10. The control unit 70 functions by loading a computer program stored in the ROM into the RAM and executing it with the CPU. The control unit 70 includes a mixed gas detection unit 71, an environmental condition detection unit 72, a recovered gas detection unit 73, an information acquisition unit 74, a calculation unit 75, and a command unit 76.

[0026] The mixed gas detector 71 detects the properties of the mixed gas flowing through the mixed gas supply passage 20. In this embodiment, the mixed gas detector 71 detects the CO2 concentration X CO2 The mixed gas detector 71 includes a concentration detector for detecting the CO2 concentration X of the mixed gas, a pressure detector for detecting the pressure Pg of the mixed gas, a thermocouple for detecting the temperature Tg of the mixed gas, and a flow rate detector for detecting the flow rate Q of the mixed gas. CO2 The mixed gas information including the pressure Pg, the temperature Tg of the mixed gas, and the flow rate Q of the mixed gas is output to the information acquiring unit 74.

[0027] The environmental condition detection unit 72 detects adsorption conditions that affect the adsorption of CO2 by the adsorbent 11 in the adsorber 10. In this embodiment, the environmental condition detection unit 72 includes a pressure detector that detects the pressure Pa inside the adsorber 10 and a thermocouple that detects the temperature Ta inside the adsorber 10. The adsorption conditions, including the pressure Pa and temperature Ta inside the adsorber 10, detected by the environmental condition detection unit 72 are output to the information acquisition unit 74.

[0028] The collected gas detection unit 73 detects the properties of the collected gas flowing through the collected gas flow path 50. In this embodiment, the collected gas is a mixture of CO2 and H2, and the collected gas detector 73 measures the CO2 concentration Xr CO2 The recovered gas detector 73 is provided with a concentration detector that detects the CO2 concentration Xr in the recovered gas, a pressure detector that detects the pressure Prg of the recovered gas, a thermocouple that detects the temperature Trg of the recovered gas, and a flow rate detector that detects the flow rate Qr of the recovered gas. CO2 The collected gas information including the collected gas pressure Prg, the collected gas temperature Trg, and the collected gas flow rate Qr is output to the information acquisition unit 74.

[0029] The information acquiring unit 74 is electrically connected to each of the mixed gas detecting unit 71, the environmental condition detecting unit 72, and the recovered gas detecting unit 73. The information acquiring unit 74 acquires gas information, which is measurement information on the properties of the gas, and adsorption conditions, which is measurement information on the environmental conditions of the adsorber, output from each of the mixed gas detecting unit 71, the environmental condition detecting unit 72, and the recovered gas detecting unit 73. The information acquiring unit 74 outputs this information to the calculating unit 75 and stores it in a memory unit (not shown). The information acquiring unit 74 may estimate the properties of the gas and the environmental conditions of the adsorber based on the information output from each of the mixed gas detecting unit 71, the environmental condition detecting unit 72, and the recovered gas detecting unit 73.

[0030] The calculation unit 75 performs various calculations and judgments using the gas properties and the environmental conditions of the adsorber input from the information acquisition unit 74. The detailed functions of the calculation unit 75 will be described later.

[0031] The command unit 76 is electrically connected to the calculation unit 75. The command unit 76 outputs commands to each unit of the collection system 5 in accordance with the calculations and determinations made by the calculation unit 75.

[0032] Next, a recovery method using the recovery system 5 will be described. In the recovery system 5 of this embodiment, three adsorbers 10 are used to continuously recover CO2 from the mixed gas, and H2 is supplied to the adsorbers 10 in the order in which CO2 recovery is completed, thereby supplying the recovered gas in which CO2 and H2 are mixed to the hydrocarbon synthesis unit 7. In the state shown in FIG. 1, the adsorber 10A is supplied with the mixed gas to adsorb CO2 to the adsorbent 11A (adsorption step), and H2 is supplied to the adsorber 10B to desorb CO2 from the adsorbent 11B (recovery step). After desorption of CO2 from the adsorbent 11C is completed, the adsorber 10C cools the adsorbent 11C heated by the heat medium (cooling step).

[0033] FIG. 2 is a flowchart illustrating a capture method using the capture system. In the capture method of this embodiment, for example, first, a mixed gas is supplied to the adsorber 10A to start capturing CO2. For the adsorber 10A, the time when the mixed gas is supplied to the adsorber 10A and capture of CO2 is started is set as ta=0 (step S11). Next, the properties of the mixed gas supplied to the adsorber 10A are acquired (step S12). In step S12, the control unit 70 uses the mixed gas detection unit 71 to detect the properties of the mixed gas flowing through the mixed gas supply flow path 20. The CO2 concentration X of the mixed gas detected by the mixed gas detection unit 71 is CO2 The pressure Pg, the temperature Tg of the mixed gas, and the flow rate Q of the mixed gas are output to the information acquisition unit 74. The information acquisition unit 74 stores these input values.

[0034] Next, when time t1 has elapsed since step S11 (step S13), the properties of the mixed gas supplied to the adsorber 10A at time t1 are acquired (step S14). In step S14, similar to step S12, the control unit 70 uses the mixed gas detection unit 71 to detect the properties of the mixed gas flowing through the mixed gas supply passage 20.

[0035] Next, the environmental conditions of the adsorber 10A are acquired (step S15). In step S15, the control unit 70 uses the environmental condition detection unit 72 to detect information about the environment inside the adsorber 10A, in particular, the pressure Pa and temperature Ta inside the adsorber 10A, which are factors that affect the adsorption of CO2 by the adsorbent 11A. The environmental conditions inside the adsorber 10A detected by the environmental condition detection unit 72 The information relating to is output to the information acquisition unit 74.

[0036] Next, the average CO2 concentration and the CO2 adsorption amount of the mixed gas flowing into the adsorber 10A are calculated (step S16). In step S16, the calculation unit 75 uses the properties of the mixed gas detected by the mixed gas detection unit 71 to calculate the average CO2 concentration of the gas flowing into the adsorber 10A at time t1 and the amount of CO2 introduced into the adsorbent 11A between time ta=0 and time t1. In this embodiment, the CO2 adsorption amount is estimated on the assumption that all CO2 introduced into the adsorber 10A is adsorbed by the adsorbent 11A. The CO2 introduction amount corresponds to the "estimated amount of introduction" in the claims. The CO2 adsorption amount corresponds to the "estimated amount of adsorption" in the claims.

[0037] In this embodiment, the average CO concentration X of the gas flowing into the adsorber from time 0 to time t CO2-ave (t) is calculated using the following formula (1): Average CO2 concentration X CO2-ave (t) indicates the average value of the CO2 concentration in the gas flowing into the adsorber from the start of the adsorption process in the adsorber until time t.

number

[0038] CO2 intake amount G from time 0 to time t t-CO2 (t) is calculated using the following formula (2).

number

[0039] The calculation unit 75 calculates the CO2 concentration X of the mixed gas using equation (2). CO2 and the flow rate q, the CO2 introduction amount G of the adsorber 10A at time t1 is calculated. t-CO2 In the present embodiment, the calculation unit 75 estimates the amount of CO adsorption in the adsorbent 11 using the amount of CO introduced thus calculated, as described above, and proceeds with the processes from step S16 onwards. At this time, the calculation unit 75 may further calculate the amount of CO introduced at time t1 using the pressure Pg and temperature Tg of the mixed gas.

[0040] In this embodiment, in step S16, the average temperature Tg of the mixed gas flowing into the adsorber 10A from the start of the adsorption process in the adsorber 10A to time t1 is calculated. -ave (t1) and the average pressure Pg -ave Calculate (t1) and the average temperature Tg -ave (t1) and the average pressure Pg -ave (t1) is used in step S19 described later.

[0041] Next, it is determined whether or not to change the set utilization rate (step S17). In step S17, the set utilization rate set for the adsorbent 11A accommodated in the adsorber 10A is changed. The user then determines whether to change the setting.

[0042] FIG. 3 is a diagram illustrating the set utilization rate of the adsorbent. FIG. 3 shows the CO2 adsorption amount (vertical axis) of the adsorbent per unit mass of the adsorbent versus the CO2 concentration (horizontal axis). Of the three curves shown in FIG. 3, the two-dot chain line Ls indicates the maximum amount of CO2 that the adsorbent can adsorb (saturated adsorption amount). The dashed line Ld indicates the CO2 adsorption amount that becomes impossible to desorb as a result of being adsorbed by the adsorbent, and the solid line La indicates the CO2 adsorption amount when CO2 is adsorbed to the adsorbent according to a certain set utilization rate. In this embodiment, the ratio of the adsorption amount Ca indicated by the solid line La to the adsorption amount Cs indicated by the two-dot chain line Ls is defined as the utilization rate Kset. In other words, the utilization rate Kset indicates the proportion of the adsorbent used to capture CO2 from the mixed gas.

[0043] In the recovery method of this embodiment, an initial value of the set utilization rate is set, and in step S17, it is determined whether or not to change the set utilization rate. In this embodiment, for the first adsorption step, the initial value is set in advance depending on the quality required for the recovered gas, but is changed for each adsorption step depending on the calculation result in step S24, which will be described later. The set utilization rate may remain fixed at the initially set value. If the calculation unit 75 determines in step S17 that the preset set utilization rate should be changed (step S17: Yes), in step S18, the calculation unit 75 changes the set utilization rate (step S18) and the process proceeds to step S19. If the calculation unit 75 determines that the set utilization rate should be changed (step S17: No), the process proceeds to step S19.

[0044] Returning to FIG. 2, the set utilization rate is used to calculate a switching threshold value as a target CO2 adsorption amount (step S19). In step S19, the calculation unit 75 first calculates the saturated adsorption amount of the adsorbent 11A. In general, the saturated adsorption amount of an adsorbent can be determined by the environmental conditions of the adsorbent and the properties of the gas supplied to the adsorbent in addition to the basic characteristics of the adsorbent. In this embodiment, the saturated adsorption amount of the adsorbent 11A is calculated by multiplying the CO2 concentration X CO2, the temperature Tg and pressure Pg, and the temperature Ta and pressure Pa in the adsorber 10A. The calculation unit 75 calculates the CO2 adsorption performance of the adsorbent 11A and the CO2 concentration X CO2 , temperature Tg, pressure Pg of the mixed gas, temperature Ta in the adsorber 10A, and pressure Pa in the adsorber 10A. When calculating the saturated adsorption amount of the adsorbent 11A, the calculation unit 75 first calculates the average temperature Ta in the adsorber 10A from the start of the adsorption process in the adsorber 10A until time t1. -ave (t1) and average pressure Pa -ave Next, the calculation unit 75 calculates the calculated average temperature Ta -ave (t1) and the average pressure Pa in the adsorber 10A -ave (t1) and the average CO2 concentration X of the mixed gas calculated in step S16 CO2-ave (t1) and the average temperature Tg of the mixed gas -ave (t1) and the average pressure of the mixed gas Pg -ave Using (t1) and the above-described data table, the calculation unit 75 calculates the current saturated adsorption amount of the adsorbent 11A. After calculating the current saturated adsorption amount of the adsorbent 11A, the calculation unit 75 multiplies the calculated saturated adsorption amount by the set utilization rate determined in step S17 or step S18 to calculate a switching threshold.

[0045] Next, it is determined whether the CO2 adsorption amount is greater than the switching threshold (step S20). In step S20, the calculation unit 75 determines whether the CO2 adsorption amount calculated in step S16 is greater than the switching threshold calculated in step S19. If the calculation unit 75 determines that the CO2 adsorption amount is equal to or less than the switching threshold (step S20: No), the process proceeds to step S21. If the calculation unit 75 determines that the CO2 adsorption amount is greater than the switching threshold (step S20: Yes), the process proceeds to step S22.

[0046] When the calculation unit 75 determines that the amount of CO2 adsorption is equal to or less than the switching threshold, the adsorption process in the adsorber 10A is continued, and after the time ta has passed since the time t1 (step S21), (t1+Δt) is set as time t1 (step S13), and the properties of the mixed gas supplied to the adsorber 10A are acquired again (step S14). After that, steps S15 to S19 are repeated, and the determination in step S20 is performed.

[0047] When the calculation unit 75 determines that the amount of CO2 adsorption is greater than the switching threshold, the command unit 76 commands a process switch (step S22). In step S22, the command unit 76 blocks the flow of mixed gas supply valve 21 toward adsorber 10A and switches to a flow toward mixed gas supply valve 22, and also opens the flow of mixed gas supply valve 22 toward adsorber 10C. As a result, the adsorber in which the adsorption process is performed is switched from adsorber 10A to adsorber 10C.

[0048] In the recovery method of this embodiment, when the adsorption process in the adsorber 10A is completed, the hydrogen supply valve 41 is opened to allow flow toward the hydrogen supply valve 42, and the hydrogen supply valve 42 is opened to allow flow toward the adsorber 10A. As a result, H2 is supplied to the adsorber 10A via the hydrogen gas supply flow path 40. In addition to the supply of H2, the adsorber 10A is also supplied with a heat medium via the heat medium flow path 60, which heats the adsorbent 11A and makes it easier to desorb the CO2 adsorbed in the adsorbent 11A. As a result, the recovered gas, which is a mixture of the CO2 desorbed in the adsorber 10A and the supplied H2, is sent to the hydrocarbon synthesis unit 7 via the recovered gas flow path 50.

[0049] When H2 is supplied to the adsorber 10A by switching the process in step S22, the CO2 adsorbed in the adsorbent 11A is desorbed from the adsorbent 11A and flows through the recovered gas flow path 50. The recovered gas flowing through the recovered gas flow path 50 is detected by the recovered gas detector 73 as a CO2 concentration Xr CO2 The information acquisition unit 74 detects the CO2 concentration Xr of the recovered gas detected by the recovered gas detection unit 73. CO2 Then, desorption amount information including pressure Prg, temperature Trg, and flow rate Qr is obtained (step S23).

[0050] The calculation unit 75 calculates the ratio of the CO2 desorption amount to the CO2 introduction amount of the adsorber 10A using the properties of the mixed gas acquired by the mixed gas detection unit 71 and the properties of the recovered gas detected by the recovered gas detection unit 73 (step S24). In step S24, the calculation unit 75 calculates the amount of CO2 supplied to the hydrocarbon synthesis unit 7 as the CO2 desorption amount using the desorption amount information, and calculates the ratio of the CO2 desorption amount to the CO2 introduction amount calculated in step S16. Here, the ratio of the CO2 desorption amount to the CO2 introduction amount of the adsorber 10A is referred to as the CO2 recovery rate of the adsorber 10A. If the calculated CO2 recovery rate is lower than the expected value, the calculation unit 75 reduces the set utilization rate in step S18 of the next adsorption step in the adsorber 10A compared to the previous set utilization rate. If the calculated CO2 capture rate is higher than the expected value, the calculation unit 75 increases the set utilization rate compared to the previous set utilization rate in step S18 of the next adsorption process in the adsorber 10A. In this way, the capture method of this embodiment changes the saturated adsorption amount and the set utilization rate in accordance with the actual conditions of the adsorber 10, stabilizes the CO2 concentration in the captured gas, and increases the CO2 capture rate. The CO2 desorption amount corresponds to the "estimated desorption amount" in the claims.

[0051] Fig. 4 is a diagram illustrating the change in the CO2 adsorption amount over time in the capture method of this embodiment. Fig. 4 shows the CO2 adsorption amount CA in each of the three adsorbers 10A, 10B, and 10C included in the capture system 5, and the switching threshold ST as the target CO2 adsorption amount to be adsorbed in one adsorber 10. Specifically, the time period from time t1 to time t2 shows the CO2 adsorption amount and switching threshold of adsorber 10A, the time period from time t2 to time t3 shows the CO2 adsorption amount and switching threshold of adsorber 10C, and the time period from time t3 to time t4 shows the CO2 adsorption amount and switching threshold of adsorber 10B.

[0052] In the recovery method of this embodiment, as shown in Fig. 4, the adsorption process ends when the CO2 adsorption amount CA exceeds the switching threshold value ST at times t2, t3, and t4 in each of the three adsorbers 10A, 10B, and 10C. In this embodiment, the saturated adsorption amount of the adsorber is calculated by multiplying the saturated adsorption amount by the set utilization rate. CO2 The switching threshold ST is calculated using the temperature Tg and pressure Pg, and the temperature Ta and pressure Pa inside the adsorber 10A, and therefore changes over time. Therefore, as shown in Fig. 4, the value of the switching threshold ST varies depending on the properties of the mixed gas and the environmental conditions of the adsorbent.

[0053] FIG. 5 shows the change in the properties of the mixed gas over time. FIG. 5(a) shows the change in the CO2 concentration of the mixed gas over time, and FIG. 5(b) shows the change in the flow rate of the mixed gas over time. In this embodiment, the mixed gas is supplied from the combustion equipment 6, and the properties of the mixed gas change over time depending on the operating state of the combustion equipment 6. Specifically, as shown in FIG. 5, the CO2 concentration changes within a range from 5% to 10%, and the flow rate changes within a range from 30 L / min to 90 L / min. When the properties of the mixed gas supplied to the adsorber 10 change significantly as shown in FIG. 5, the saturated adsorption amount of the adsorbent 11 also changes.

[0054] FIG. 6 is a diagram illustrating the relationship between the utilization rate of the adsorbent and the quality of the recovered gas. In the adsorber 10 shown in FIG. 6, the mixed gas flows into the adsorber 10 through the inlet 12. The remaining gas from the mixed gas, from which CO2 has been removed by adsorption by the adsorbent 11, is discharged through the outlet 13. Therefore, CO2 contained in the mixed gas is adsorbed sequentially, starting with the adsorbent 11 closest to the inlet 12. Therefore, the adsorbent 11 includes an adsorbent located on the inlet 12 side of the adsorber 10 that adsorbs CO2 (region Ra1 shown in FIG. 6), and an adsorbent located on the outlet 13 side of the adsorber 10 that does not adsorb CO2 but adsorbs gases other than CO2 contained in the mixed gas (region Ra2 shown in FIG. 6). Here, in this embodiment, the gases other than CO2 contained in the mixed gas include oxygen, nitrogen, moisture, etc.

[0055] In a capture system, when CO2 is desorbed from the adsorbent 11 to capture CO2, it is desirable that the CO2 concentration of the captured gas be constant to facilitate utilization in a downstream process (hydrocarbon production). Therefore, at the end of the adsorption process, it is desirable that the ratio (utilization rate) of the adsorbent 11 adsorbing CO2 to the entire adsorbent 11 be constant. However, as shown in FIG. 6 , even when the boundary between the adsorbent 11 adsorbing CO2 and the adsorbent 11 adsorbing gases other than CO2 is set as boundary B1, the saturated adsorption amount of the adsorbent 11 varies depending on the properties of the mixed gas and the operating conditions of the adsorber 10. Therefore, in this embodiment, in order to maintain a constant utilization rate of the adsorbent 11, the saturated adsorption amount of the adsorbent 11 is calculated using the properties of the mixed gas and the adsorption conditions of the adsorber 10, thereby adjusting the utilization rate of the adsorbent 11 to be constant (steps S17 to S19 shown in FIG. 2 ). This stabilizes the quality of the recovered gas. Although the quality of the recovered gas is stabilized when the adsorbent utilization rate is set to 100%, some of the CO2 contained in the mixed gas is discharged without being adsorbed by the adsorbent. Therefore, in order to increase the CO2 concentration in the recovered gas while minimizing CO2 leakage, it is desirable to set the utilization rate to, for example, about 60% to 90%.

[0056] FIG. 7 is a diagram illustrating the change in the average CO2 concentration in the adsorption process and the adsorption process time. FIG. 7 shows the change in the average CO2 concentration in the mixed gas in the adsorption process of the recovery method of this embodiment (FIG. 7(a)) and the time for one adsorption process (FIG. 7(b)). The horizontal axis of FIG. 7 indicates the number of processes. As shown in FIG. 7(a), in the recovery system 5, the average CO2 concentration X CO2-ave differs between adsorption steps, and in the case of a mixed gas with such an unstable composition, the quality of the recovered gas may not be stable. In this embodiment, as described above, the time Tabs for one adsorption step is changed based on the saturated adsorption amount of the adsorbent 11 calculated using the properties of the gas so that the utilization rate of the adsorbent 11 is constant (see FIG. 7(b)).

[0057] Figure 8 is the first diagram illustrating the adsorbent utilization rate and CO2 capture rate. Figure 8 shows the time evolution of the adsorbent utilization rate (Figure 8(a)) and the CO2 capture rate (Figure 8(b)) when the adsorption process is repeated. As shown in Figure 8(a), immediately after the start of the capture method, there is no CO2 in the adsorber, so CO2 is not completely desorbed and remains in the adsorber. As a result, the CO2 concentration is unstable and changes over time. However, in the example shown in Figure 8, the adsorbent utilization rate stabilizes after 15 hours have passed since the start of the capture method. Furthermore, Figure 8(b) shows that once the adsorbent utilization rate stabilizes, the CO2 capture rate also stabilizes. This indicates that the quality of the captured gas is stable. Note that in the experimental example shown in Figure 8, the adsorbent utilization rate (kset) is set to 0.6, and the CO2 capture rate is nearly 100%. In other words, almost all of the CO2 contained in the mixed gas was captured. As shown in Figure 8(a), the actual utilization rate after 15 hours from the start of the capture method is greater than the set utilization rate of 0.6. This is because the actual utilization rate of the adsorbent includes the adsorbent that has adsorbed CO2 that cannot be desorbed as a result of being adsorbed by the adsorbent.

[0058] FIG. 9 is a second diagram illustrating the adsorbent utilization rate and CO2 capture rate. FIG. 9 shows the changes in the adsorbent utilization rate (FIG. 9(a)) and the CO2 capture rate (FIG. 9(b)) relative to the average CO2 concentration of the mixed gas. In the experimental example shown in FIG. 9, the average CO2 concentration of the mixed gas varies from less than 6% to more than 8%. However, as shown in FIG. 9(a), the adsorbent utilization rate is maintained between 0.65 and 0.68, and the CO2 capture rate is also stable, as can be seen from FIG. 9(b). Therefore, it was revealed that in the capture system 5 of this embodiment, the CO2 capture rate for each capture process is stable even if the average CO2 concentration of the mixed gas changes.

[0059] FIG. 10 is a diagram illustrating the effect of changes in the ambient temperature on the adsorbent. FIG. 10(a) is a diagram illustrating changes in the CO2 adsorption amount due to changes in the ambient temperature of the adsorbent. Generally, the adsorption amount of an adsorbent for gases such as CO2 decreases as the ambient temperature increases. In other words, the saturated adsorption amount of the adsorbent changes with changes in the ambient temperature of the adsorbent. FIG. 10(b) shows the process average change in the adsorbent temperature due to changes in the ambient temperature in each of multiple adsorption processes. As shown in FIG. 10(b), in the capture system 5 of this embodiment, not only does the average CO2 concentration change, but the average temperature of the adsorbent also changes.

[0060] FIG. 11 is a third diagram illustrating the adsorbent utilization rate and CO2 capture rate. FIG. 11 shows the changes in the adsorbent utilization rate (FIG. 11(a)) and the CO2 capture rate (FIG. 11(b)) relative to the CO2 concentration of the mixed gas when the ambient temperature of the adsorbent changes for each adsorption process. In the experimental example shown in FIG. 11, even when the average adsorbent temperature changes as shown in FIG. 10(b), the adsorbent utilization rate is mostly maintained at a value of around 0.7 as shown in FIG. 11(a), and the CO2 capture rate is also stable as shown in FIG. 11(b). Therefore, it was revealed that in the capture system 5 of this embodiment, the CO2 capture rate for each capture process is stable even when the ambient temperature of the adsorbent changes.

[0061] FIG. 12 is a fourth diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. FIG. 13 is a fifth diagram illustrating the utilization rate of the adsorbent and the CO2 recovery rate. FIG. 12 shows the change in the CO2 concentration of the mixed gas when the amount of heat medium supplied by the heat medium flow path 60 becomes less than the expected amount, for the utilization rate of the adsorbent (FIG. 12(a)) and the CO2 recovery rate (FIG. 12(b)). For example, if a malfunction of the recovery system 5 causes the flow rate of the heat medium flowing through the heat medium flow path 60 to become 40% of the expected amount, leaving the utilization rate Kset of the adsorbent 11 at 0.6 will result in insufficient heat and CO2 desorption failure in the recovery process. This makes it easier for CO2 to remain in the adsorber 10, and as shown in FIG. 12(a), the utilization rate rises to around 0.9. As the utilization rate rises, the CO2 concentration in the recovery process will decrease. Since O2 cannot be completely recovered, the CO2 recovery rate decreases as shown in FIG. 12(b), and gas from which CO2 has not been completely removed flows into the exhaust gas flow path 30.

[0062] In this embodiment, the calculation unit 75 calculates the CO2 capture rate of the adsorber 10 using the properties of the captured gas acquired by the information acquisition unit 74 and the properties of the mixed gas acquired by the mixed gas detection unit 71 (see step S24 in FIG. 2). If the CO2 capture rate has decreased, the calculation unit 75 reduces the set utilization rate in the next adsorption step to restore the CO2 capture rate. Specifically, in the situation shown in FIG. 12, the utilization rate Kset is changed from 0.6 to 0.4. As a result, as shown in FIG. 13, the utilization rate becomes approximately 0.6, and the adsorption step time is shortened, making it possible to reliably capture the CO2 contained in the mixed gas. Therefore, the CO2 capture rate can be restored, as shown in FIG. 13(b).

[0063] According to the recovery apparatus 1 of the present embodiment described above, the control unit 70 switches the adsorber 10 to which the mixed gas is supplied based on the CO adsorption capacity and saturated adsorption capacity of the adsorbent 11, which are estimated using mixed gas information including the temperature of the mixed gas and adsorption conditions including the ambient temperature of the adsorbent 11. The saturated adsorption capacity of the adsorbent 11 is affected by the properties of the mixed gas supplied to the adsorber 10 and environmental conditions that affect the adsorption performance of the adsorbent 11, so the saturated adsorption capacity estimated in this manner is a value appropriate for the actual situation. By switching the supply destination of the mixed gas based on the CO adsorption capacity and saturated adsorption capacity of the adsorbent 11 estimated by the calculation unit 75, it is possible to stabilize the proportion of the adsorbent 11 used for CO adsorption (utilization rate) while suppressing CO leakage outside the system. Therefore, when recovering CO adsorbed on the adsorbent 11, the CO concentration in the recovered gas can be kept constant, thereby stabilizing the quality of the recovered gas.

[0064] Furthermore, according to the recovery apparatus 1 of this embodiment, the calculation unit 75 estimates the amount of CO introduced into the adsorber 10 between the start of the adsorption process and a specific time t1 as the CO introduction amount, and uses the estimated CO introduction amount to estimate the CO adsorption amount adsorbed by the adsorbent 11. The calculation unit 75 compares the estimated CO adsorption amount with a switching threshold calculated by multiplying the saturated adsorption amount by a set utilization rate. The command unit 76 switches the adsorber 10 to which the mixed gas is supplied based on the comparison result. That is, the recovery apparatus 1 estimates the CO adsorption amount of the adsorbent 11 using only the mixed gas information, and can switch the supply destination of the mixed gas by comparing it with the switching threshold. This allows for easy stabilization of the quality of the recovered gas.

[0065] Furthermore, according to the recovery device 1 of this embodiment, the calculation unit 75 calculates the set utilization rate using the ratio of the amount of CO2 desorption to the amount of CO2 introduced, i.e., the CO2 recovery rate. This makes it possible to stabilize the CO2 recovery rate, which is one of the qualities of the recovered gas, and therefore further stabilize the quality of the recovered gas.

[0066] Furthermore, according to the recovery apparatus 1 of this embodiment, the saturated adsorption amount of the adsorbent 11 is estimated using the average values ​​of the properties of the mixed gas and the average values ​​of the environmental conditions from the start of supply of the mixed gas to the adsorber 10 until a specific time. This makes it possible to estimate the saturated adsorption amount of the adsorbent 11 even if there is a sudden change in the properties of the mixed gas or the environmental conditions after the start of supply of the mixed gas to the adsorber 10, thereby stabilizing the quality of the recovered gas.

[0067] Furthermore, according to the recovery method of this embodiment, the recovery device 1 switches the adsorber 10 that supplies the mixed gas in accordance with the saturated adsorption amount of the adsorbent 11 calculated using the mixed gas information and the adsorption conditions. This makes it possible to stabilize the utilization rate of the adsorbent 11, and therefore the quality of the recovered gas.

[0068] According to the computer program of this embodiment, the control unit 70 receives mixed gas information and The adsorbent to which the mixed gas is supplied is switched depending on the saturated adsorption amount of the adsorbent 11 calculated using the adsorption conditions. This makes it possible to stabilize the utilization rate of the adsorbent, and therefore the quality of the recovered gas.

[0069] Second Embodiment 14 is a schematic diagram showing the general configuration of a recovery device of the second embodiment. The recovery device of the second embodiment differs from the recovery device of the first embodiment (FIG. 1) in that the recovery device detects the concentration of impurities contained in the mixed gas.

[0070] The control unit 70 included in the recovery system 5 of this embodiment includes a mixed gas detection unit 77, an environmental condition detection unit 72, an information acquisition unit 74, a calculation unit 75, and a command unit 76. The mixed gas detection unit 77 detects the properties of the mixed gas flowing through the mixed gas supply flow path 20. The mixed gas detection unit 77 includes a CO2 concentration detector, a pressure detector that detects the pressure Pg, a thermocouple that detects the temperature Tg, a flow rate detector that detects the flow rate Q, and a flow rate detector that detects the concentration X of components other than CO2 in the mixed gas. ip The CO2 concentration X detected by the mixed gas detection unit 77 is an impurity concentration detector. CO2, impurity concentration ip The mixed gas information including the pressure Pg, the temperature Tg, and the flow rate Q is output to the information acquisition unit 74.

[0071] Figure 15 is a diagram illustrating the effect of changes in the ambient temperature on an adsorbent. Generally, adsorbents for gases such as CO2 will also adsorb impurity gases if the mixed gas containing the gas to be adsorbed also contains other gases than the gas to be adsorbed, i.e., impurity gases. Therefore, if the mixed gas contains impurity gases, the saturated adsorption capacity of the adsorbent for the gas to be adsorbed decreases, and if the concentration of the impurity gas increases, the saturated adsorption capacity of the adsorbent for the gas to be adsorbed decreases (see Figure 15).

[0072] In the recovery method of this embodiment, when calculating the switching threshold in step S19 (see FIG. 2), the control unit 70 uses not only the temperature Tg and pressure Pg of the mixed gas and the temperature Ta and pressure Pa inside the adsorber 10, but also the impurity concentration X ip In this embodiment, the calculation unit 75 calculates the saturated adsorption amount by using the adsorption performance of the adsorbent 11 for CO2, the temperature Tg of the mixed gas, the pressure Pg of the mixed gas, and the impurity concentration X ip , the temperature Ta in the adsorber 10A, and the pressure Pa in the adsorber 10A. The calculation unit 75 calculates the saturated adsorption amount of the adsorbent 11 using this data table, and calculates the switching threshold by multiplying it by the set utilization rate. As a result, in the recovery method of this embodiment, the impurity concentration X ip The switching threshold is changed according to the change.

[0073] According to the recovery device 2 of this embodiment described above, the mixed gas detection unit 77 acquires mixed gas information, including the concentrations of substances other than CO2 contained in the mixed gas. Because the adsorbent 11 also adsorbs substances other than CO2, such as H2O, the saturated adsorption amount of the adsorbent 11 decreases. Therefore, by estimating the saturated adsorption amount of the adsorbent 11 using the concentrations of substances other than CO2, the estimation accuracy of the saturated adsorption amount can be improved. This improves the accuracy of the timing for switching the supply destination of the mixed gas, thereby further stabilizing the quality of the recovered gas.

[0074] Third Embodiment 16 is a schematic diagram showing the general configuration of a recovery device of the third embodiment. The recovery device of the third embodiment differs from the recovery device of the first embodiment (FIG. 1) in that the recovery device detects the concentration of CO2 contained in the exhaust gas.

[0075] The control unit 70 included in the recovery system 5 of this embodiment is a mixed gas detection unit 71 and an environmental condition The exhaust gas detecting unit 78 includes a detecting unit 72, an exhaust gas detecting unit 78, an information acquiring unit 74, a calculating unit 75, and a command unit 76. The exhaust gas detecting unit 78 detects the properties of the exhaust gas flowing through the exhaust gas flow path 30. The exhaust gas detecting unit 78 detects the CO2 concentration Xe CO2 The exhaust gas detector 78 includes a concentration detector that detects the CO2 concentration eX, a pressure detector that detects the exhaust gas pressure Peg, a thermocouple that detects the exhaust gas temperature Teg, and a flow rate detector that detects the exhaust gas flow rate Qe. CO2 The exhaust gas information including the pressure Peg, the temperature Teg, and the flow rate Qe is output to the information acquisition unit 74.

[0076] In the recovery method of this embodiment, the calculation unit 75 calculates the CO2 concentration X CO2 and the flow rate Q are used to calculate the amount of CO2 introduced, and the CO2 concentration Xe in the exhaust gas detected by the exhaust gas detection unit 78 is CO2and the flow rate Qe to calculate the CO2 emission amount. The calculation unit 75 calculates the CO2 adsorption amount using the difference between the CO2 introduction amount and the CO2 emission amount. In step S20 (see FIG. 2), the calculation unit 75 determines whether the CO2 adsorption amount calculated in this manner is greater than the switching threshold value. The CO2 emission amount corresponds to the "emission amount estimated value" in the claims.

[0077] According to the recovery apparatus 3 of this embodiment described above, the calculation unit 75 estimates the CO2 adsorption amount using the difference between the amount of CO2 introduced into the adsorber 10 and the amount of CO2 emitted from the adsorber 10. The control unit 70 compares the estimated CO2 adsorption amount with a switching threshold to switch the adsorber 10 to supply the mixed gas. This improves the accuracy of estimating the CO2 adsorption amount of the adsorbent 11 when determining the supply destination of the mixed gas, thereby enabling the command unit 76 to accurately switch the supply destination of the mixed gas. This further stabilizes the quality of the recovered gas.

[0078] <Modification of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0079] [Variation 1] In the above-described embodiment, the recovery devices 1, 2, and 3 are applied to a recovery system 5 that recovers carbon dioxide from a mixed gas containing moisture and the like. However, the application field of the recovery device is not limited to this. The recovery device can be applied to any system that uses an adsorbent to adsorb and recover a specific substance from a mixed gas.

[0080] [Variation 2] In the above-described embodiment, the calculation unit 75 calculates the saturated adsorption amount and the CO2 introduction amount using the values ​​detected (measured) by the mixed gas detection unit 71, the environmental condition detection unit 72, etc. The calculation unit 75 may also estimate the saturated adsorption amount and the CO2 introduction amount from the values ​​detected by the mixed gas detection unit 71, the environmental condition detection unit 72, etc.

[0081] [Variation 3] In the above-described embodiment, the mixed gas detection unit 71 detects the CO2 concentration of the mixed gas, the pressure Pg of the mixed gas, the temperature Tg of the mixed gas, and the flow rate Q of the mixed gas. The environmental condition detection unit 72 detects the pressure Pa and temperature Ta inside the adsorber 10. The values ​​detected by these detection units are not limited to these. Any value may be used as long as it allows the saturated adsorption amount of the adsorbent 11 and the amount of CO2 introduced to be calculated or estimated. The same applies to the mixed gas detection unit 77 of the second embodiment and the exhaust gas detection unit 78 of the third embodiment.

[0082] [Variation 4] In the above embodiment, the calculation unit 75 calculates the average temperature in the adsorber 10 and the average The saturated adsorption amount of the adsorbent 11 is calculated using the pressure, the average temperature of the mixed gas, and the average temperature of the mixed gas. However, the numerical value used to calculate the saturated adsorption amount of the adsorbent 11 does not have to be an average value.

[0083] [Variation 5] In the above-described embodiment, the utilization rate of the adsorbent 11 is adjusted to be constant by calculating the saturated adsorption amount of the adsorbent 11 using the properties of the mixed gas and the adsorption conditions of the adsorber 10, with the aim of maintaining a constant utilization rate of the adsorbent 11. However, the utilization rate of the adsorbent 11 does not have to be constant. For example, the utilization rate of the adsorbent may be changed depending on the CO concentration of the mixed gas or the characteristics of the adsorbent. For example, the utilization rate of the adsorbent may be set higher as the CO concentration decreases depending on the characteristics of the adsorbent.

[0084] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0085] 1, 2, 3... Recovery device 10,10A,10B,10C…Adsorber 11,11A,11B,11C…Adsorbent 70...Control unit 71, 77...Mixed gas detector 72...Environmental condition detection unit 73...Environmental condition detection unit 74…Information acquisition department 75...Arithmetic section 76...Command Department 78...Exhaust gas detection unit kset…Utilization rate

Claims

1. A recovery device for recovering a specific substance contained in a mixed gas, an adsorbent that accommodates an adsorbent that adsorbs the specific substance; an acquisition unit that acquires mixed gas information, which is estimated or measured information on the properties of the mixed gas supplied to the adsorber, including the temperature of the mixed gas, and adsorption conditions, which is estimated or measured information on environmental conditions that affect the adsorption performance of the adsorbent, including the environmental temperature of the adsorbent; an estimation unit that estimates an adsorption amount estimate value of the adsorbent and a saturated adsorption amount of the adsorbent using the mixed gas information and the adsorption conditions; a switching unit that switches the adsorber to which the mixed gas is supplied in accordance with the estimated adsorption amount value and the saturated adsorption amount.

2. The recovery device according to claim 1, The estimation unit Using the mixed gas information, an estimated amount of the specific substance introduced into the adsorber is estimated; using the estimated introduction amount estimate value, estimating the adsorption amount estimate value representing the amount of the specific substance adsorbed by the adsorbent at a specific time point; calculating a switching threshold value by multiplying the saturated adsorption amount estimated using the mixed gas information by a control constant; the switching unit compares the estimated adsorption amount with the switching threshold value to switch the adsorber to which the mixed gas is supplied. Recovery device.

3. The recovery device according to claim 1, the acquisition unit acquires exhaust gas information, which is estimated information or measured information on the properties of the exhaust gas, including a flow rate of the exhaust gas discharged from the adsorber and a concentration of the specific substance in the exhaust gas; The estimation unit Using the mixed gas information, an estimated amount of the specific substance introduced into the adsorber is estimated; Using the exhaust gas information, an estimated emission amount of the specific substance emitted from the adsorber is estimated; using a difference between the estimated amount introduced and the estimated amount released, to estimate the estimated amount of adsorption, which represents the amount of the specific substance adsorbed by the adsorbent at a specific time point; calculating a switching threshold value by multiplying the saturated adsorption amount estimated using the mixed gas information by a control constant; the switching unit compares the estimated adsorption amount with the switching threshold value to switch the adsorber to which the mixed gas is supplied. Recovery device.

4. The recovery device according to claim 2 or 3, the acquisition unit acquires desorption amount information, which is estimated information or measured information of the desorption amount of the specific substance desorbed from the adsorbent that has adsorbed the specific substance; The estimation unit Estimating a desorption amount estimate value using the desorption amount information; calculating the control constant using a ratio of the estimated desorption amount to the estimated introduction amount; Recovery device.

5. The recovery device according to any one of claims 2 to 4, The estimation unit using the mixed gas information, calculating an average value of the properties of the mixed gas from the start of supply of the mixed gas to the adsorber to the specific time point; calculating an average value of the environmental condition from the start of supply of the mixed gas to the adsorber to the specific time point using the adsorption condition; estimating a saturated adsorption amount of the adsorbent using an average value of the properties of the mixed gas and an average value of the environmental conditions; Recovery device.

6. The recovery device according to any one of claims 1 to 5, the acquisition unit acquires the mixed gas information including concentrations of substances other than the specific substance contained in the mixed gas; the estimation unit estimates the saturated adsorption amount of the adsorbent using the concentrations of gases other than the specific substance contained in the mixed gas, which are included in the mixed gas information. Recovery device.

7. A recovery method for recovering a specific substance contained in a mixed gas by a recovery device, comprising: a step of adsorbing the specific substance onto an adsorbent; acquiring mixed gas information, which is estimated or measured information on the properties of the mixed gas supplied to an adsorber, including the temperature of the mixed gas; and adsorption conditions, which is estimated or measured information on environmental conditions that affect the adsorption performance of the adsorbent, including the environmental temperature of the adsorbent; estimating an adsorption amount estimate of the adsorbent and a saturated adsorption amount of the adsorbent using the mixed gas information and the adsorption conditions; and switching the adsorber to which the mixed gas is supplied in accordance with the estimated adsorption amount value and the saturated adsorption amount. Recovery method.

8. A computer program that causes a computer to execute recovery of a specific substance contained in a mixed gas, A function of adsorbing the specific substance onto an adsorbent; a function of acquiring mixed gas information, which is estimated or measured information on the properties of the mixed gas supplied to an adsorber containing the adsorbent, including the temperature of the mixed gas, and adsorption conditions, which is estimated or measured information on environmental conditions that affect the adsorption performance of the adsorbent, including the environmental temperature of the adsorbent; a function of estimating an adsorption amount estimate value of the adsorbent and a saturated adsorption amount of the adsorbent using the mixed gas information and the adsorption conditions; and switching the adsorber to which the mixed gas is supplied in accordance with the estimated adsorption amount and the saturated adsorption amount. Computer program.

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