Gas separator and gas separation method

Abstract

To provide a gas separator that eliminates installation of a regeneration heater and achieves reduction of running costs, and a gas separation method.SOLUTION: A gas separator comprises: an exhaust gas introduction line L1 for introducing a high-temperature exhaust gas 11; a moisture removal part 14 which comprises a moisture adsorbent 12 which performs moisture adsorption process and regeneration process, and adsorbs / removes moisture 13 in the high-temperature exhaust gas 11; a dehumidified gas discharge line L2 which removes a dehumidified gas 11A from the moisture removal part 14; a carbon dioxide gas separation part 22 to which the tip of the dehumidified gas discharge line L2 is connected, which comprises a carbon dioxide gas adsorbent 21, and adsorbs / separates the carbon dioxide gas in the dehumidified gas 11A; a decarbonated gas supply line L3-1 which supplies a decarbonated gas 11B, in which the carbon dioxide gas is separated from the dehumidified gas 11A, to the moisture removal part 14; and a heat exchanger 31 which is provided at an intersection part between the exhaust gas introduction line L1 and the decarbonated gas supply line L3-1, and heats the decarbonated gas 11B by the high-temperature exhaust gas 11.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gas separation apparatus and a gas separation method for separating moisture and carbon dioxide gas contained in an exhaust gas. [Background technology]

[0002] Here, there has been a proposal to use a PSA (Pressure Swing Adsorption) device as a separation device for removing impurities from the gas (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3841792 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in proposals such as Patent Document 1, in order to regenerate the adsorbent used in the PSA device, it is necessary to install a regeneration heater and heat the adsorbent to a predetermined regeneration temperature (e.g., about 170°C) to obtain regenerated gas, and there is a problem in that using this regeneration heater incurs running costs.

[0005] In view of the above problems, the present invention provides a gas separation apparatus and a gas separation method which eliminate the need for a regenerative heater and thus reduce running costs. [Means for solving the problem]

[0006] One embodiment of a gas separation apparatus according to the present invention is characterized in that it comprises an exhaust gas inlet line for introducing high-temperature exhaust gas, a moisture removal section for removing moisture from the high-temperature exhaust gas, a dehumidified gas line for discharging dehumidified gas from the moisture removal section, a carbon dioxide separation section for separating carbon dioxide from the dehumidified gas, a decarbonated gas supply line for supplying decarbonated gas obtained by separating the carbon dioxide from the dehumidified gas to the moisture removal section, and a heat exchanger provided at the intersection of the exhaust gas inlet line and the decarbonated gas supply line for heating the decarbonated gas with the high-temperature exhaust gas.

[0007] One embodiment of the gas separation method according to the present invention is characterized by a moisture removal process for separating moisture from an introduced high-temperature exhaust gas, a carbon dioxide separation process for separating carbon dioxide from a dehumidified gas from which moisture has been removed in the moisture removal process, and heating the decarbonated gas with the high-temperature exhaust gas and using it as a regeneration gas for the moisture removal process. Effect of the Invention

[0008] According to the present invention, the need for a regenerative heater in a PSA apparatus is eliminated, and running costs can be reduced. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a gas separation apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic process diagram of a gas separation apparatus according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic process diagram of a gas separation apparatus according to a first alternative embodiment of the present invention. [Figure 4] FIG. 2 is a schematic process diagram of a gas separation apparatus according to a first alternative embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic process diagram of a gas separation apparatus according to a first alternative embodiment of the present invention. [Figure 6] FIG. 4 is a schematic process diagram of a gas separation apparatus according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments of this specification, the same components are denoted by the same reference numerals throughout.

[0011] [First embodiment] Fig. 1 is a schematic diagram of a gas separation apparatus according to a first embodiment of the present invention, Fig. 2 to Fig. 5 are schematic process diagrams of the gas separation apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the exhaust gas separation device 10 of this embodiment includes a moisture removal section 14 that removes moisture and a carbon dioxide separation section 22 that separates carbon dioxide (CO2) from the dehumidified gas 11A after moisture removal, and removes moisture (dehumidification) from the high-temperature exhaust gas 11 and separates carbon dioxide from the dehumidified gas 11A after dehumidification.

[0012] Further detailed description will be given with reference to Fig. 2. As shown in Fig. 2, the flue gas separation apparatus 10A-1 of this embodiment includes an flue gas introduction line L1 for introducing a high-temperature flue gas 11, a moisture removal section 14 (14-1, 14-2) which is provided with a moisture adsorbent 12 performing a moisture adsorption process and a regeneration process and adsorbs and removes moisture 13 in the high-temperature flue gas 11, a dehumidified gas line L2 for discharging a dehumidified gas 11A from the moisture removal section 14, a carbon dioxide gas separation section 22 (22-1, 22-2) to which the end of the dehumidified gas line L2 is connected and which is provided with a carbon dioxide gas adsorbent 21 performing a carbon dioxide gas adsorption process and a regeneration process and adsorbs and separates carbon dioxide gas in the dehumidified gas 11A, and a decarbonated gas supply line L for supplying a decarbonated gas 11B obtained by separating carbon dioxide gas from the dehumidified gas 11A to the moisture removal section 14. 3-1 , exhaust gas introduction line L1 and decarbonated gas supply line L 3-1 and a heat exchanger 31 for heating the decarbonated gas 11B with the high-temperature exhaust gas 11.

[0013] In this embodiment, the moisture removal section 14 includes two towers, a first moisture removal section 14-1 and a second moisture removal section 14-2. The carbon dioxide gas separation section 22 also includes two towers, a first carbon dioxide gas removal section 22-1 and a second carbon dioxide gas removal section 22-2. The present invention is not limited to two columns, and may be one column or two or more columns, and is not limited thereto. In the case of using multiple columns, a pressure equalizing means for equalizing the pressure of each column may be provided.

[0014] Here, the moisture removal section 14 and the carbon dioxide separation section 22 may be implemented using a known PSA (Pressure Swing Adsorption) device, a TSA (Thermal Swing Adsorption) device, a VSA (Vacuum Swing Adsorption) device, a PVSA (Pressure Vacuum Swing Adsorption) device, or the like.

[0015] In addition, as shown in FIG. 2, in the exhaust gas separation apparatus 10A-1, a high-temperature exhaust gas bypass line L6 that bypasses the heat exchanger 31 and introduces high-temperature exhaust gas to the downstream side of the heat exchanger 31 is provided in the exhaust gas introduction line L1. In addition, a decarbonated gas bypass line L is provided to bypass the heat exchanger 31 and supply the decarbonated gas to the moisture removing section 14. 3-2 We strive to provide the following:

[0016] In addition, the tip of the exhaust gas introduction line L1 is connected to one end (the lower end in the figure) of the moisture removal section 14. The rear end of the dehumidified gas line L2 is connected to the upper end in the figure of the moisture removal section 14. The tip of the dehumidified gas line L2 is connected to the lower end in the figure of the carbon dioxide gas separation section 22. The rear end of the decarbonated gas supply line L3 is connected to the upper end in the figure of the carbon dioxide gas separation section 22, and its tip is connected to the upper end in the figure of the moisture removal section 14. In addition, V1 to V 10 is the opening and closing valve on the moisture removal section 14 side, V 11 ~V 16 Illustrated is an opening and closing valve on the carbon dioxide gas separation section 22 side.

[0017] In such an apparatus, as shown in FIG. 2, high-temperature exhaust gas 11 is introduced into one end of a first moisture removal section 14-1 through an exhaust gas introduction line L1. Here, the high-temperature exhaust gas to be introduced can be, for example, high-temperature combustion exhaust gas from combustion equipment such as a boiler, but is not limited to combustion exhaust gas, and can be, for example, blast furnace gas.

[0018] <Exhaust gas dehumidification process> 2, in the exhaust gas separation apparatus 10A-1, the valve V1 on the inlet side and the valve V5 on the outlet side of the first moisture removal section 14-1 are open in the moisture removal section 14. In the figure, the valves marked with black dots indicate that the valves are open, and the valves marked with white dots indicate that the valves are closed.

[0019] When the introduced high-temperature exhaust gas 11 passes through the first moisture removal section 14-1, moisture is removed by the filled moisture adsorbent 12. Note that, before being introduced into the first moisture removal section 14-1, the high-temperature exhaust gas 11 is cooled to a predetermined adsorption temperature of the moisture adsorbent 12 (for example, 40°C or lower) by a cooler 15 installed in the exhaust gas introduction line L1. Note that, a drain tank 16 is provided downstream of the cooler 15. Here, examples of the moisture adsorbent 12 of the moisture remover 14 include zeolite, activated alumina, and silica gel, but the present invention is not limited to these.

[0020] <CO2 separation process> In the carbon dioxide gas separation section 22, the valve V of the first carbon dioxide gas separation section 22-1 11 and Valve V 15 and is open. The dehumidified gas 11A from which moisture has been removed in the first moisture removal section 14-1 is introduced from one end of the first carbon dioxide gas separation section 22-1 via a dehumidified gas line L2 connected to the other end of the second moisture removal section 14-1. When the introduced dehumidified gas 11A passes through the first carbon dioxide gas separation section 22-1, the carbon dioxide gas is adsorbed and separated by the filled carbon dioxide gas adsorbent 21.

[0021] Here, examples of the adsorbent for separating carbon dioxide gas in the carbon dioxide gas separation section 22 include zeolite, activated carbon, silica, etc., but the present invention is not limited to these. In particular, when zeolite is used,

[0022] In the moisture removing section 14, the valves V9 and V4 of the second moisture removing section 14-2 are open. The decarbonated gas 11B from which carbon dioxide has been separated is fed to the decarbonated gas supply line L 3-1 The exhaust gas is supplied to the second moisture removal section 14-2 via the exhaust gas introduction line L1 and the decarbonated gas supply line L 3-1 The low-temperature decarbonated gas 11B is heated by the high-temperature exhaust gas 11 through a heat exchanger 31 provided at the intersection with the high-temperature exhaust gas 11. The decarbonated gas 11C heated to a high temperature (for example, 150° C. or higher) is supplied to the second moisture removal section 14-2.

[0023] <Regeneration process of the adsorbent in the second moisture removal section 14-2> 2, the moisture adsorbent 12 that has already adsorbed moisture is regenerated by the heated decarbonated gas 11C supplied to the second moisture removal section 14-2. Moisture 13 generated during regeneration is discharged to the outside through the drain line L4.

[0024] <Regeneration process of the adsorbent in the second carbon dioxide gas separation section 22-2> In the exhaust gas separation apparatus 10A-1 of FIG. 2, in the carbon dioxide gas separation section 22, the valve V 14 In the second carbon dioxide gas separation section 22-2, the carbon dioxide gas (CO2) is sucked from the carbon dioxide gas adsorbent 21 to which the carbon dioxide gas has already been adsorbed using a vacuum pump P2, and the carbon dioxide gas (CO2) is discharged to the outside through a carbon dioxide gas discharge line L5, and the carbon dioxide gas adsorbent 21 is regenerated.

[0025] <Step of cooling the adsorbent in the second moisture removal section 14-2> In the exhaust gas separation apparatus 10A-2 of FIG. 3, in the moisture removal section 14, the valve V 10 and valve V4 are open. In this exhaust gas separation device 10A-2, a decarbonated gas bypass line L 3-2 is connected to the second moisture removal section 14-2, and the low-temperature decarbonated gas 11B is directly introduced into the second moisture removal section 14-2 to cool the regenerated moisture adsorbent 12 and prepare for the next dehumidification.

[0026] At this time, the valve V 21 and close the valve V6 installed on the bypass line L6. 22 is set to "open". This causes the high-temperature exhaust gas 11 to bypass the heat exchanger 31 and is introduced to the front side of the cooler 15. As a result, when the high-temperature exhaust gas 11 is not exchanging heat with the low-temperature decarbonated gas 11B in the heat exchanger 31, no high-temperature gas is introduced into the heat exchanger 31, so that the heat exchanger 31 can be protected.

[0027] <Dehumidification process> In the exhaust gas separation apparatus 10A-3 of Fig. 4, the valves V3 and V8 of the second moisture removal section 14-2 are open in the moisture removal section 14. As in the process in the exhaust gas separation apparatus 10A-1 of Fig. 2, the high-temperature exhaust gas 11 is introduced into one end of the second moisture removal section 14-2 through the exhaust gas introduction line L1 to continuously remove moisture. When the introduced high-temperature exhaust gas 11 passes through the second moisture removal section 14-2, moisture is removed by the moisture adsorbent 12 filled therein.

[0028] <CO2 separation process> In the exhaust gas separation apparatus 10A-3 of FIG. 4, in the carbon dioxide gas separation section 22, the valve V 13 and Valve V 16 and is open. In addition, in the moisture removing section 14, the valve V6 and the valve V2 of the first moisture removing section 14-1 are open. The dehumidified gas 11A from which moisture has been removed in the second moisture removing section 14-2 is introduced from one end of the second carbon dioxide gas separating section 22-2 via a dehumidified gas line L2 connected to the second moisture removing section 14-2. The introduced dehumidified gas 11A adsorbs and separates carbon dioxide gas by the carbon dioxide gas adsorbent 21 while passing through the second carbon dioxide gas separation section 22-2.

[0029] The decarbonated gas 11B from which carbon dioxide has been separated is fed to the decarbonated gas supply line L 3-1 The water is supplied to the first moisture removal section 14-1 via the At this time, the exhaust gas introduction line L1 and the decarbonated gas supply line L 3-1 The decarbonated gas 11B is heated by the high-temperature exhaust gas 11 through a heat exchanger 31 provided at the intersection with the high-temperature exhaust gas 11. The heated decarbonated gas 11C is supplied to the first moisture removal section 14-1.

[0030] <Regeneration process of the adsorbent in the first moisture removal section 14-1> The heated decarbonated gas 11C supplied to the first moisture removal section 14-1 regenerates the moisture adsorbent 12 that has already adsorbed moisture. Moisture 13 generated during regeneration is discharged to the outside through a drain line L4.

[0031] <Regeneration process of the adsorbent in the first carbon dioxide gas separation section 22-1> In the exhaust gas separation apparatus 10A-3 of FIG. 4, in the carbon dioxide gas separation section 22, the valve V 12 is open. Then, the carbon dioxide gas is sucked from the carbon dioxide gas adsorbent 21, in which carbon dioxide gas has already been adsorbed in the first carbon dioxide gas separation section 22-1, using a vacuum pump P2, and the carbon dioxide gas is released to the outside through a carbon dioxide gas discharge line L5, and the carbon dioxide gas adsorbent 21 is regenerated.

[0032] <Step of cooling the adsorbent in the first moisture removal section 14-1> In the exhaust gas separation apparatus 10A-4 of FIG. 5, in the moisture removal section 14, the valve V7 and the valve V2 of the first moisture removal section 14-1 are open. In the exhaust gas separation device 10A-4 of FIG. 5, a decarbonated gas bypass line L 3-2is directly connected to the other end of the first moisture removal section 14-1, and low-temperature decarbonated gas 11B is introduced into the first moisture removal section 14-1 to cool the regenerated moisture adsorbent 12 and prepare for the next dehumidification. At this time, the valve V 21 and close the valve V6 installed on the bypass line L6. 22 is set to “open” so that the high-temperature exhaust gas 11 bypasses the heat exchanger 31 and is introduced to the front side of the cooler 15 .

[0033] This protects the heat exchanger when the high-temperature exhaust gas 11 is not exchanging heat with the low-temperature decarbonated gas 11B in the heat exchanger 31. The moisture 13 generated during this regeneration is discharged to the outside through the drain line L4.

[0034] In this embodiment, a PSA device has been described as an example of the carbon dioxide separation section 22, but the present invention is not limited to this, and other devices capable of separating carbon dioxide, such as a device using a membrane separation method in which carbon dioxide is separated using a membrane or a device using a cryogenic separation method, may be used as appropriate.

[0035] In addition, in this embodiment, carbon dioxide gas is exemplified as the gas to be removed, but the present invention may also be applied to separating gases to be removed other than carbon dioxide gas (gases such as nitrogen oxides and sulfur oxides).

[0036] As described above, according to this embodiment, the decarbonated gas 11B, which is the off-gas of the PSA unit, is heated in the heat exchanger 31 by using the introduced high-temperature exhaust gas 11, and is used as the heated decarbonated gas 11C for regeneration in the moisture removal step. This eliminates the need to install a regeneration heater in the PSA unit, and allows for reduced running costs. In addition, compared with the case where the regeneration treatment is performed at room temperature, the packed volume of the adsorbent can be reduced.

[0037] This will provide an economical technology that can efficiently separate and recover carbon dioxide from exhaust gas, helping to realize a carbon-free society.

[0038] [Second embodiment] 6 is a schematic diagram of a gas separation apparatus according to a second embodiment of the present invention. The same components as those in the first embodiment are given the same reference numerals and the description thereof will be omitted. As shown in FIG. 6, the exhaust gas separation apparatus 10B of this embodiment includes a decarbonated gas supply line L between the heat exchanger 31 and the moisture removal unit 14. 3-1 The heater 41 is provided.

[0039] By providing this heater 41, the regeneration gas temperature of the heated decarbonated gas 11C can be further increased, thereby enabling a further reduction in the packing volume of the adsorbent. [Industrial Applicability]

[0040] The present invention can be applied to the entire technology of gas separation devices. [Explanation of symbols]

[0041] 10, 10A-1~4, 10B Gas separation device 11 High-temperature exhaust gas 11A Dehumidified gas 11B Decarbonation 11C Heated decarbonated gas 12 Moisture absorbent 13. Moisture 14 Moisture removal section 14-1 1st moisture removal section 14-2 Second moisture removal section 21 Carbon dioxide absorbent 22 Carbon dioxide separation section 22-1 First carbon dioxide gas separation section 22-2 Second carbon dioxide separation section 31 Heat exchanger 41 Heater P1 gas introduction pump P2 Vacuum Pump L1 exhaust gas introduction line L2 Dehumidified gas line L3 Decarbonated gas supply line L 3-1 Decarbonated gas supply line L 3-2 Decarbonation gas bypass line L4 drain line L5 Carbon dioxide exhaust line L6 High-temperature exhaust gas bypass line

Claims

1. □ An exhaust gas introduction line for introducing high-temperature exhaust gas; A moisture removal section for removing moisture from the high-temperature exhaust gas; A dehumidified gas line for discharging the dehumidified gas from the moisture removing unit; A carbon dioxide gas separation unit that separates carbon dioxide gas from the dehumidified gas; A decarbonated gas supply line that supplies the decarbonated gas obtained by separating the carbon dioxide gas from the dehumidified gas to the moisture removing unit; a heat exchanger provided at an intersection of the exhaust gas inlet line and the decarbonated gas supply line for heating the decarbonated gas with the high-temperature exhaust gas.

2. The gas separation apparatus according to claim 1, characterized in that the exhaust gas introduction line is provided with a high-temperature exhaust gas bypass line that bypasses the heat exchanger and introduces the high-temperature exhaust gas into the downstream side of the heat exchanger.

3. The gas separation apparatus according to claim 1, further comprising a decarbonated gas bypass line that bypasses the heat exchanger and supplies the decarbonated gas to the moisture removal section.

4. The gas separation apparatus according to claim 1 or 2, further comprising a heater provided in a decarbonated gas supply line between the heat exchanger and the moisture removing section.

5. A moisture removal process to remove moisture from the introduced high-temperature exhaust gas; A carbon dioxide gas separation step of separating carbon dioxide gas from the dehumidified gas from which moisture has been removed in the moisture removal step; A gas separation method, comprising heating the decarbonated gas with the high-temperature exhaust gas and using the gas as a regeneration gas in a moisture removal step.

6. A gas separation method according to claim 5, characterized in that the regeneration gas is further heated.

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