Carbon dioxide capture device

Abstract

The present invention provides a carbon dioxide recovery device that can improve carbon dioxide adsorption performance while increasing the utilization rate of waste heat from a heat exchanger. [Solution] The carbon dioxide recovery device comprises an air passage 2 connected to the outlet of an air-cooled heat exchanger 1, an adsorbent 3 that adsorbs carbon dioxide in the air introduced through the air passage 2, a temperature sensor 4 that detects the temperature of the air in the air passage 2, a flow rate adjustment unit 5 that introduces air from outside the air passage 2 into the air passage 2, and a control device 6 that controls the flow rate adjustment unit 5 based on the detection result of the temperature sensor 4.

Description

Technical Field

[0001] The present invention relates to a carbon dioxide recovery device that recovers carbon dioxide in the air discharged from an air-cooled heat exchanger.

Background Art

[0002] Patent Document 1 discloses a carbon dioxide recovery device that recovers carbon dioxide in the exhaust gas discharged from an internal combustion engine of a vehicle. This carbon dioxide recovery device includes an exhaust passage connected to the internal combustion engine, an adsorbent that adsorbs carbon dioxide in the exhaust gas introduced through the exhaust passage, an exhaust temperature sensor that detects the temperature of the exhaust gas in the exhaust passage, a bypass passage branched from the upstream side of the adsorbent in the exhaust passage, an exhaust valve provided in the bypass passage, and an ECU that controls the opening degree of the exhaust valve based on the detection result of the exhaust temperature sensor.

[0003] The adsorbent is composed of, for example, zeolite or the like, and physically adsorbs carbon dioxide in the exhaust gas. This adsorbent has the characteristic that the lower the temperature, the higher the adsorption performance.

[0004] When the deviation between the temperature of the exhaust gas detected by the exhaust temperature sensor and the target temperature is 0 or less, the ECU sets the opening degree of the exhaust valve to 0. When the deviation between the temperature of the exhaust gas detected by the exhaust temperature sensor and the target temperature is greater than 0, the ECU increases the opening degree of the exhaust valve in response to the increase in the deviation. Thereby, a part of the exhaust gas discharged from the internal combustion engine is released, and the flow rate of the exhaust gas introduced into the adsorbent is adjusted. As a result, the temperature of the adsorbent is adjusted, and the adsorption performance of the adsorbent is improved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] While Patent Document 1 deals with exhaust gas emitted from an internal combustion engine of a vehicle, the present invention deals with air emitted from an air-cooled heat exchanger used in industrial machinery and the like. In other words, the present invention relates to a carbon dioxide recovery device for recovering carbon dioxide from air emitted from an air-cooled heat exchanger. In this carbon dioxide recovery device, since the waste heat of the heat exchanger is utilized, it is conceivable to employ an adsorbent that chemically adsorbs carbon dioxide from the air. Furthermore, in order to improve the adsorption performance by adjusting the temperature of the adsorbent, it is conceivable to configure the device to release a portion of the air emitted from the heat exchanger and adjust the flow rate of air introduced to the adsorbent, similar to Patent Document 1. However, in this configuration, since a portion of the air emitted from the heat exchanger is released, the utilization rate of the waste heat of the heat exchanger decreases.

[0007] This invention has been made in view of the above matters, and one of its objectives is to improve carbon dioxide adsorption performance while increasing the utilization rate of waste heat from a heat exchanger. [Means for solving the problem]

[0008] To solve the above problems, the configuration described in the claims is applied. The carbon dioxide recovery device of the present invention includes a plurality of means for solving the above problems, but to give one example, it comprises an air passage connected to the outlet of an air-cooled heat exchanger, an adsorbent for adsorbing carbon dioxide in the air introduced through the air passage, a first temperature sensor for detecting the temperature of the air in the air passage, a flow rate adjustment unit for introducing air from outside the air passage into the air passage, and a control device for controlling the flow rate adjustment unit based on the detection result of the first temperature sensor. [Effects of the Invention]

[0009] According to the present invention, it is possible to improve carbon dioxide adsorption performance while increasing the utilization rate of waste heat from a heat exchanger.

[0010] Furthermore, other issues, structures, and effects not mentioned above will be clarified in the following explanation. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the configuration of a carbon dioxide recovery device in a first embodiment of the present invention. [Figure 2] This is a schematic diagram showing the configuration of a carbon dioxide recovery device in a second embodiment of the present invention. [Figure 3] This is a schematic diagram showing the configuration of a carbon dioxide recovery device in a third embodiment of the present invention. [Figure 4] This is a schematic diagram showing the configuration of a carbon dioxide recovery device in one modified example of the present invention. [Modes for carrying out the invention]

[0012] A first embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic diagram showing the configuration of the carbon dioxide capture device in this embodiment.

[0013] The carbon dioxide recovery device of this embodiment comprises an air passage 2 connected to the outlet of an air-cooled heat exchanger 1 used in industrial machinery, etc., an adsorbent 3 that adsorbs carbon dioxide in the air introduced through the air passage 2, a temperature sensor 4 that detects the temperature of the air in the air passage 2, a flow rate adjustment unit 5 that introduces air from outside the air passage 2 into the air passage 2, and a control device 6 that controls the flow rate adjustment unit 5 based on the detection result of the temperature sensor 4. The flow rate adjustment unit 5 has a blower 7 and a passage 8 that introduce air from outside the air passage 2 into the air passage 2.

[0014] The heat exchanger 1 cools a fluid (for example, compressed air discharged from a compressor, or a refrigerant that cools it) by heat exchange with air from a blower 9. The heat exchanger 1 can be, for example, a plate type, a fin and tube type, or a shell and tube type. A plate type heat exchanger has a plurality of stacked plates (heat transfer plates), with air passages and fluid passages alternately formed between the plurality of plates. A fin and tube type heat exchanger has tubes (heat transfer tubes) through which the fluid flows and fins attached to the outside of the tubes, with air passages formed on the outside of the tubes. A shell and tube type heat exchanger has tubes (heat transfer tubes) through which the fluid flows and a shell (body) that houses the tubes and through which air flows.

[0015] The adsorbent 3 is composed of compounds such as calcium, magnesium, or sodium, or a carrier containing an amine-based absorbent solution, and chemically adsorbs carbon dioxide from the air introduced through the air channel 2. Compared to physical adsorbents that physically adsorb carbon dioxide from the air, this adsorbent 3 (chemical adsorbent) can enhance its adsorption performance by utilizing the waste heat from the heat exchanger 1. The adsorbent 3 may be installed on its own or housed in a permeable component.

[0016] The temperature sensor 4 is positioned in the airflow path 2 downstream of the point where air is introduced by the flow rate adjustment unit 5 (right side in Figure 1). The temperature sensor 4 is a contact type, such as a thermocouple, resistance thermometer, thermistor thermometer, bimetallic thermometer, or filled thermometer. Alternatively, the temperature sensor 4 is a non-contact type, such as a radiation thermometer, thermograph, or quantum infrared sensor.

[0017] The control device 6 includes a processor that executes processing according to a program, and memory for storing programs and data. Functionally, the control device 6 has a temperature control unit 10.

[0018] The temperature control unit 10 of the control device 6 controls the flow rate adjustment unit 5 so that the temperature of the air detected by the temperature sensor 4 is within a predetermined range (specifically, a range set around the target temperature at which the adsorption performance of the adsorbent 3 increases). More specifically, when the temperature of the air detected by the temperature sensor 4 is within the predetermined range, the rotation speed of the blower 7 (that is, the flow rate of the air introduced into the air flow path 2) is maintained. When the temperature of the air detected by the temperature sensor 4 is higher than the predetermined range, the rotation speed of the blower 7 is increased. When the temperature of the air detected by the temperature sensor 4 is lower than the predetermined range, the rotation speed of the blower 7 is decreased. As a result, the temperature of the adsorbent is adjusted, and the adsorption performance of the adsorbent is improved.

[0019] In addition, when the adsorbent 3 is composed of a calcium compound, the target temperature is, for example, 60°C. When the adsorbent 3 is composed of a magnesium compound, the target temperature is, for example, 200°C. When the adsorbent 3 is composed of a sodium compound, the target temperature is, for example, 35°C.

[0020] In the present embodiment configured as described above, by adjusting the temperature of the air introduced into the adsorbent 3, the carbon dioxide adsorption performance can be improved. Further, instead of releasing a part of the air discharged from the heat exchanger 1, external air is introduced to adjust the temperature of the air introduced into the adsorbent 3, so that the utilization rate of the waste heat of the heat exchanger 1 can be increased.

[0021] The second embodiment of the present invention will be described with reference to FIG. 2. FIG. 2 is a schematic diagram showing the configuration of the carbon dioxide recovery device in the present embodiment. In the present embodiment, parts equivalent to those in the first embodiment are denoted by the same reference numerals, and the description will be omitted as appropriate.

[0022] The carbon dioxide recovery device of this embodiment further includes a flow rate sensor 11 that detects the flow rate of air in the air flow path 2 and a temperature sensor 12 that detects the temperature of the air outside the air flow path 2. The temperature sensor 4 and the flow rate sensor 11 are arranged in the air flow path 2 so as to be on the upstream side (the left side in FIG. 2) from the position where air is introduced by the flow rate adjustment unit 5. The flow rate sensor 11 is, for example, a thermal type, a turbine type, a Karman type, a Coriolis type, or a differential pressure type, etc.

[0023] The temperature control unit 10 of the control device 6 estimates the temperature of the air introduced into the adsorbent 3 based on the detection results of the temperature sensor 4, the flow rate sensor 11, and the temperature sensor 12, and the flow rate of the air introduced by the flow rate adjustment unit 5. The temperature control unit 10 controls the flow rate adjustment unit 5 so that the estimated air temperature falls within a predetermined range (specifically, a range set around the target temperature at which the adsorption performance of the adsorbent 3 is enhanced). More specifically, when the estimated air temperature is within the predetermined range, the rotation speed of the blower 7 (that is, the flow rate of the air introduced into the air flow path 2) is maintained. When the estimated air temperature is higher than the predetermined range, the rotation speed of the blower 7 is increased according to the difference between the estimated air temperature and the target temperature. When the estimated air temperature is lower than the predetermined range, the rotation speed of the blower 7 is decreased according to the difference between the estimated air temperature and the target temperature.

[0024] Even in this embodiment configured as described above, as in the above embodiment, it is possible to improve the carbon dioxide adsorption performance while increasing the utilization rate of the waste heat of the heat exchanger 1.

[0025] In the second embodiment, the case where the carbon dioxide recovery device includes the temperature sensor 12 that detects the temperature of the air outside the air flow path 2 has been described as an example, but it is not limited to this, and the temperature sensor 12 may not be provided. In this case, the temperature control unit 10 of the control device 6 uses a set value as the temperature of the air outside the air flow path 2. That is, the temperature control unit 10 of the control device 6 estimates the temperature of the air introduced into the adsorbent 3 based on the detection results of the temperature sensor 4 and the flow rate sensor 11, and the flow rate of the air introduced by the flow rate adjustment unit 5.

[0026] A third embodiment of the present invention will be described with reference to Figure 3. Figure 3 is a schematic diagram showing the configuration of the carbon dioxide capture device in this embodiment. In this embodiment, parts equivalent to those in the first and second embodiments are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0027] The carbon dioxide recovery device of this embodiment further includes a humidity sensor 13 for detecting the humidity of the air in the air channel 2, and a humidity adjustment unit 14 for adjusting the humidity of the air in the air channel 2.

[0028] The humidity sensor 13 is positioned in the airflow path 2 so as to be upstream of the humidity adjustment unit 14. The humidity sensor 13 can be, for example, an electric type, an electromagnetic wave absorption type, a heat conduction type, a wet / dry bulb type, or a telescopic type.

[0029] The humidity control unit 14 includes an inlet, a first outlet, a second outlet, and a third outlet, a four-way valve 15 that selectively switches the first, second, and third outlets to communicate with the inlet, a flow path 16A connected between the first outlet of the four-way valve 15 and the adsorbent 3, a flow path 16B connected between the second outlet of the four-way valve 15 and the adsorbent 3, a humidifier 17 provided in the flow path 16B, a flow path 16C connected between the third outlet of the four-way valve 15 and the adsorbent 3, and a dehumidifier 18 provided in the flow path 16C.

[0030] The control device 6 further includes a humidity control unit 20 as part of its functional configuration. Based on the detection results of the humidity sensor 13, the humidity control unit 20 controls the humidity adjustment unit 14 so that the humidity of the air introduced into the adsorbent 3 is within a predetermined range (more specifically, a range set around a target humidity that enhances the adsorption performance of the adsorbent 3). More specifically, when the humidity of the air detected by the humidity sensor 13 is within the predetermined range, the first outlet of the four-way valve 15 is controlled to communicate with the inlet. When the humidity of the air detected by the humidity sensor 13 is lower than the predetermined range, the second outlet of the four-way valve 15 is controlled to communicate with the inlet, and the capacity of the humidifier 17 is controlled according to the difference between the humidity of the air detected by the humidity sensor 13 and the target humidity. When the humidity of the air detected by the humidity sensor 13 is higher than the predetermined range, the third outlet of the four-way valve 15 is controlled to communicate with the inlet, and the capacity of the dehumidifier 18 is controlled according to the difference between the humidity of the air detected by the humidity sensor 13 and the target humidity.

[0031] If adsorbent 3 is composed of a calcium compound, the target humidity is, for example, 75%.

[0032] In this embodiment, configured as described above, the carbon dioxide adsorption performance can be improved while increasing the utilization rate of the waste heat from the heat exchanger 1, similar to the above embodiment. In this embodiment, the carbon dioxide adsorption performance can be further improved by adjusting not only the temperature but also the humidity of the air introduced into the adsorbent 3.

[0033] In the third embodiment, the example described was that the humidity sensor 13 is located upstream of the humidity adjustment unit 14 in the airflow path 2, but the invention is not limited to this. The humidity sensor 13 may also be located downstream of the humidity adjustment unit 14 in the airflow path 2.

[0034] Furthermore, the third embodiment is illustrated as an example in which a humidity sensor 13, a humidity adjustment unit 14, and a humidity control unit 20 of the control device 6 are added to the second embodiment, but it is not limited to this, and a humidity sensor 13, a humidity adjustment unit 14, and a humidity control unit 20 of the control device 6 may also be added to the first embodiment.

[0035] In the first to third embodiments, the carbon dioxide recovery device was described using an example where the flow rate adjustment unit 5 includes a blower 7 and a flow path 8, and the temperature control unit 10 of the control device 6 controls the blower 7. However, the invention is not limited to this. For example, as shown in the modified example in Figure 4, the carbon dioxide recovery device may not include a blower 7 and a flow path 8, and the temperature control unit 10 of the control device 6 may control a blower 9, which corresponds to the flow rate adjustment unit. To explain in more detail, the temperature control unit 10 maintains the rotation speed of the blower 9 (i.e., the flow rate of air introduced into the air flow path 2) when the air temperature detected by the temperature sensor 4 is within a predetermined range. When the air temperature detected by the temperature sensor 4 is higher than the predetermined range, the rotation speed of the blower 7 is increased within a range that does not hinder the cooling of the fluid by the heat exchanger 1. When the air temperature detected by the temperature sensor 4 is lower than the predetermined range, the rotation speed of the blower 7 is decreased within a range that does not hinder the cooling of the fluid by the heat exchanger 1.

[0036] Furthermore, in the first to third embodiments, the case in which the air passage 2 is connected to the outlet of one heat exchanger 1 was described as an example, but it is not limited to this. The air passage 2 may be connected to the outlets of multiple heat exchangers 1. [Explanation of Symbols]

[0037] 1…Heat exchanger, 2…Air passage, 3…Adsorbent, 4…Temperature sensor (first temperature sensor), 5…Flow rate adjustment unit, 6…Control device, 7…Blower, 11…Flow rate sensor, 12…Temperature sensor (second temperature sensor), 13…Humidity sensor, 14…Humidity adjustment unit

Claims

1. An air passage connected to the outlet of an air-cooled heat exchanger, An adsorbent that adsorbs carbon dioxide from the air introduced through the aforementioned air passage, A first temperature sensor for detecting the temperature of the air in the air passage, A flow rate adjustment unit that introduces air from outside the air passage into the air passage, A carbon dioxide recovery device characterized by comprising a control device that controls the flow rate adjustment unit based on the detection result of the first temperature sensor.

2. In the carbon dioxide recovery apparatus according to claim 1, The carbon dioxide recovery device is characterized in that the first temperature sensor is positioned in the airflow path downstream of the point where air is introduced by the flow rate adjustment unit.

3. In the carbon dioxide recovery apparatus according to claim 2, The carbon dioxide recovery device is characterized in that the control device controls the flow rate adjustment unit so that the temperature of the air detected by the first temperature sensor falls within a predetermined range.

4. In the carbon dioxide recovery apparatus according to claim 1, The system further includes a flow sensor for detecting the flow rate of air in the aforementioned air passage, A carbon dioxide recovery device characterized in that the first temperature sensor and the flow rate sensor are arranged in the airflow path upstream of the position where air is introduced by the flow rate adjustment unit.

5. In the carbon dioxide recovery apparatus according to claim 4, The carbon dioxide recovery apparatus is characterized in that the control device estimates the temperature of the air introduced into the adsorbent based on the detection results of the first temperature sensor and the flow rate sensor and the flow rate of the air introduced by the flow rate adjustment unit, and controls the flow rate adjustment unit so that the estimated air temperature is within a predetermined range.

6. In the carbon dioxide recovery apparatus according to claim 5, The system further includes a second temperature sensor for detecting the temperature of the air outside the air passage, The carbon dioxide recovery apparatus is characterized in that the control device estimates the temperature of the air introduced into the adsorbent based on the detection results of the first temperature sensor, the flow rate sensor, and the second temperature sensor, and the flow rate of the air introduced by the flow rate adjustment unit, and controls the flow rate adjustment unit so that the estimated temperature of the air is within a predetermined range.

7. In the carbon dioxide recovery apparatus according to claim 1, A humidity sensor for detecting the humidity of the air in the aforementioned airflow channel, The system further includes a humidity control unit that adjusts the humidity of the air within the aforementioned air passage, The carbon dioxide recovery apparatus is characterized in that the control device controls the humidity adjustment unit based on the detection result of the humidity sensor so that the humidity of the air introduced into the adsorbent is within a predetermined range.

8. In the carbon dioxide recovery apparatus according to claim 1, The carbon dioxide recovery device is characterized in that the flow rate adjustment unit has a blower that introduces air from outside the air passage into the air passage.

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