Carbon dioxide capture device and method

Abstract

The invention relates to a carbon dioxide capturing device and method. The carbon dioxide capturing device comprises an air inlet pipeline, an exhaust pipeline, a first carbon dioxide capturing module and a second carbon dioxide capturing module, the first carbon dioxide capture module is used for carrying out a water mist mixing reaction, and a calcium hydroxide aqueous solution is used as a carbon dioxide capture carrier; the second carbon dioxide capture module is arranged below the air inlet pipeline, the first carbon dioxide capture module and the exhaust pipeline and is used for carrying out an aeration washing reaction; wherein waste gas enters through the gas inlet pipeline, is subjected to multi-channel water mist mixing by the first carbon dioxide capture module, is subjected to aeration water washing by the second carbon dioxide capture module, and is exhausted through the exhaust pipeline. By means of the dual reaction mechanism, the reaction between the calcium hydroxide aqueous solution and the target carbon dioxide gas can be improved, so that the capture efficiency of carbon dioxide is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide treatment, and particularly to a carbon dioxide capture device and method, which sequentially carry out a water mist mixing reaction and an aeration water washing reaction between waste gas and an aqueous calcium hydroxide solution. Background Art

[0002] The world has faced the problems of increasing greenhouse gases and energy shortages. However, for the next few decades, fossil fuels will still be the main primary energy sources. How to reduce carbon dioxide emissions has become an important global issue. Currently, carbon dioxide capture technology refers to the recovery of carbon dioxide emitted from energy sources such as power generation, petrochemical, steel, cement, and paper making. Carbon dioxide can be captured by methods such as absorption, adsorption, and membrane separation.

[0003] Furthermore, traditional carbon dioxide capture technologies (such as dry calcium oxide, alkanolamine, membrane filtration, etc.) have commercial equipment products due to the continuous development of the global net-zero emissions drive. However, carbon dioxide capture carriers and processes individually have limitations such as a high operating temperature range, potential chemical hazards, high consumable and equipment investment thresholds, etc.

[0004] A patent document (publication number TWI646050B) discloses a carbon dioxide collection method, which includes the following steps: contacting a capture agent solution with a to-be-treated substance containing carbon dioxide to obtain a capture agent solution that has captured carbon dioxide. Among them, the capture agent solution contains at least one capture agent for capturing carbon dioxide, and the capture agent is selected from potassium phosphate, potassium ethylenediaminetetraacetate, or potassium salts of monoprotic carboxylic acids with a total carbon number of 12 or less. However, this patent document uses a chemical capture liquid reagent instead of using an aqueous calcium hydroxide solution as a carbon dioxide capture carrier.

[0005] Therefore, there is a need to provide a carbon dioxide capture device and method that can solve the aforementioned problems. Summary of the Invention

[0006] An object of the present invention is to provide a carbon dioxide capture device and method, which sequentially carry out a water mist mixing reaction and an aeration water washing reaction between waste gas and an aqueous calcium hydroxide solution.

[0007] According to the above object, the present invention provides a carbon dioxide capture device, comprising: an intake pipeline, an exhaust pipeline, a first-stage carbon dioxide capture module, and a second-stage carbon dioxide capture module; the first-stage carbon dioxide capture module is disposed in the intake pipeline for performing a water mist mixing reaction, wherein an aqueous calcium hydroxide solution is used as a carbon dioxide capture carrier; the second-stage carbon dioxide capture module is disposed below the intake pipeline, the first-stage carbon dioxide capture module, and the exhaust pipeline and is used for performing an aeration water washing reaction; wherein an exhaust gas enters through the intake pipeline, is first subjected to multiple water mist mixings of the exhaust gas by the first-stage carbon dioxide capture module, then subjected to aeration water washing of the exhaust gas by the second-stage carbon dioxide capture module, and then discharged through the exhaust pipeline.

[0008] The present invention further provides a carbon dioxide capture method, comprising the following steps: performing multiple water mist mixings on an exhaust gas to achieve a first-stage carbon dioxide capture reaction, wherein an aqueous calcium hydroxide solution is used as a carbon dioxide capture carrier; and using the carrier solution after the multiple water mist mixings to perform aeration water washing on the exhaust gas to achieve a second-stage carbon dioxide capture reaction.

[0009] The carbon dioxide capture device and method of the present invention use an aqueous calcium hydroxide solution, which is easy to operate, has low chemical hazards, and is low in cost, as a carbon dioxide capture carrier, and cooperate with the device mechanism to sequentially perform a water mist mixing reaction and an aeration water washing reaction between the exhaust gas (such as process exhaust gas) and the aqueous calcium hydroxide solution. Through this dual reaction mechanism, the reaction between the aqueous calcium hydroxide solution and the target carbon dioxide gas can be enhanced to improve the carbon dioxide capture efficiency. Description of the Drawings

[0010] Figure 1 It is a cross-sectional schematic view of the carbon dioxide capture device according to the first embodiment of the present invention.

[0011] Figure 2 It is a cross-sectional schematic view of a venturi tube structure formed between a second pump, an air inlet, and a water inlet in an embodiment of the present invention.

[0012] Figure 3 It is a cross-sectional schematic view of the carbon dioxide capture device according to the second embodiment of the present invention.

[0013] Figure 4 It is a block schematic view of the carbon dioxide capture device and the exhaust gas emission treatment device in an embodiment of the present invention.

[0014] Figure 5 It is a step flow chart of the carbon dioxide capture method in an embodiment of the present invention.

[0015] Symbol Description in the Drawings:

[0016] 1 carbon dioxide capture device; 1' carbon dioxide capture device; 11 first-stage carbon dioxide capture module; 111 first pump; 112 solution pipeline; 1121 nozzle; 12 second-stage carbon dioxide capture module; 120 water tank; 121 second pump; 122 air inlet; 123 spray outlet; 124 water inlet; 125 water inlet partition; 126 carrier solution; 13 third-stage carbon dioxide capture module; 131 third pump; 132 another solution pipeline; 1321 nozzle; 14 intake pipeline; 141 inlet; 15 exhaust pipeline; 151 outlet; 16 electronic control module; 161 first sensing component; 162 second sensing component; 163 third sensing component; 164 frequency converter; 165 monitoring and display interface; 2 waste gas emission treatment device; θ included angle. Detailed implementation manners

[0017] To make the above objects, features and characteristics of the present invention more obvious and understandable, the related embodiments of the present invention will be described in detail below in conjunction with the drawings.

[0018] The embodiments of the present invention will be described in detail below in conjunction with the drawings. The drawings are mainly simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner. Therefore, only the components related to the present invention are marked in these drawings, and the components shown are not drawn according to the number, shape, size ratio, etc. during implementation. The actual implementation specifications and dimensions are actually a selective design, and the component layout form may be more complex.

[0019] Figure 1 It is a cross-sectional schematic diagram of the carbon dioxide capture device according to the first embodiment of the present invention. Please refer to Figure 1 , the carbon dioxide capture device 1 includes: an intake pipeline 14, an exhaust pipeline 15, a first-stage carbon dioxide capture module 11 and a second-stage carbon dioxide capture module 12. The intake pipeline 14 is used to connect to the waste gas emission source to be treated. The exhaust pipeline 15 is used to connect to the gas environment where the treated gas is to be discharged. The first-stage carbon dioxide capture module 11 is disposed in the intake pipeline 14 for performing a water mist mixing reaction, in which an aqueous calcium hydroxide solution (Ca(OH) 2(aq) ) is used as the carbon dioxide capture carrier. The first-stage carbon dioxide capture module 11 includes: a first pump 111 and a solution pipeline 112. The solution pipeline 112 has a plurality of nozzles 1121. These nozzles 1121 are located in the intake pipeline 14, and the first pump 111 is used to transport a carrier solution 126 to these nozzles 1121 of the solution pipeline 112 for generating a water mist mixing reaction. The carrier solution 126 includes an aqueous calcium hydroxide solution. Although Figure 1Only two solution pipelines 112 arranged in parallel are shown, but the present invention is not limited thereto. In other examples, the number and arrangement of the solution pipelines 112 and the configuration of the nozzles 1121 can be adjusted according to actual operating conditions and capture efficiency. For example, the number of the solution pipelines 112 can be at least one, and the extending direction of each solution pipeline 112 can have the same or different included angles (such as 0 degrees to 90 degrees) with the gas inlet direction in the intake pipeline 14, and the spraying direction of the nozzle 1121 can be the same as, opposite to, or have an included angle with the gas inlet direction.

[0020] The second-stage carbon dioxide capture module 12 is disposed below the intake pipeline 14, the first-stage carbon dioxide capture module 11, and the exhaust pipeline 15, and is used to perform an aeration water washing reaction. The second-stage carbon dioxide capture module 12 includes a water tank 120, a second pump 121, an air inlet 122, a water inlet 124, and a spray outlet 123. The water inlet 124 and the spray outlet 123 are disposed in the water tank 120. A carrier solution 126 is provided in the water tank 120. The water inlet 124 is disposed below the liquid level of the carrier solution 126, and the second pump 121 is connected to the air inlet 122, the water inlet 124, and the spray outlet 123 to mix the waste gas entering the air inlet 122 and the carrier solution 126 entering the water inlet 124 and transport them to the spray outlet 123 to generate an aeration water washing reaction. The water tank 120 is provided with a water inlet partition 125 to isolate the connection between the intake pipeline 14 and the exhaust pipeline 15. Please refer to Figure 2 , which shows that a venturi tube structure is formed among the second pump 121, the air inlet 122, and a water inlet 124.

[0021] According to the carbon dioxide capture device 1 of the present invention, an exhaust gas (such as process exhaust gas) enters through the intake pipe 14. First, the first-stage carbon dioxide capture module 11 performs multi-stage water mist mixing on the exhaust gas, and then the second-stage carbon dioxide capture module 12 performs aeration water washing on the exhaust gas (referring to the exhaust gas that has passed through the first-stage carbon dioxide capture module 11), and then discharges it through the exhaust pipe 15. Specifically, after the process exhaust gas enters through the intake pipe 14, the multi-stage water mist mixing of the first-stage carbon dioxide capture module 11 first generates a first-stage carbon dioxide capture reaction on the exhaust gas, and then the intake port 122 of the second-stage carbon dioxide capture module 12 sucks it in and performs aeration water washing with the carrier solution 126 (containing calcium carbonate) in the water tank 120 to achieve a second-stage carbon dioxide capture reaction. The intake port 122 of the second-stage carbon dioxide capture module 12 can generate a negative pressure suction effect through the venturi tube structure, and the aerated water flow is guided to the other end of the water tank 120 through the spray outlet 123, so that the reacted exhaust gas can naturally float and flow out through the exhaust pipe 15 for discharge. The water inlet partition 125 can cooperate with the liquid level of the water tank 120 to isolate the connection between the intake pipe 14 and the exhaust pipe 15, preventing the un-aerated and water-washed gas from directly flowing out through the exhaust pipe 15, and at the same time preventing the intake port 122 of the second-stage carbon dioxide capture module 12 from sucking in the exhaust gas that has been aerated and water-washed again.

[0022] The main chemical formula of the first-stage water mist mixing reaction:

[0023] Ca(OH) 2(aq) +CO 2(g) →CaCO 3(g) ↓+H 2 O (l)

[0024] Calcium hydroxide (aqueous solution) + carbon dioxide (gaseous) → calcium carbonate (solid) ↓ + water (liquid)

[0025] For the test of the above reaction, under the environment of 1 atmosphere and 27 °C, carbon dioxide gas was continuously introduced into the carrier solution. The carrier solution was composed of 0.04 g (0.0005 mole) of calcium hydroxide and 25 g of pure water, with a weight molar concentration of 0.02 m and a pH of 12.35. After a reaction time of 20 seconds, the carrier solution was measured, and the calculated carbon dioxide capture effect was 41.8 g (0.95 mole) of carbon dioxide captured per mole of calcium bicarbonate, and the pH value changed by 9.42.

[0026] The main chemical formula of the second-stage aeration water washing reaction:

[0027] CaCO 3(s) +CO 2(g) +H 2 O (l)→Ca(HCO 3 ) 2(aq)

[0028] Calcium carbonate (solid) + carbon dioxide (gas) + water (liquid) → calcium bicarbonate (aqueous solution)

[0029] For the test of the said reaction, under the environment of 1 atmosphere and 27 °C, carbon dioxide gas was continuously introduced into the carrier solution. The carrier solution was composed of 0.05 g (0.0005 mole) of calcium carbonate and 25 g of pure water, with a weight molar concentration of 0.02 m and a pH of 9.42. After a reaction time of 20 seconds, the carrier solution was measured, and it was calculated that the carbon dioxide capture effect was 38.28 g (0.87 mole) of carbon dioxide captured per mole of calcium hydroxide, and the pH value changed by 7.36.

[0030] The carbon dioxide capture carrier used in the present invention is an aqueous solution of calcium hydroxide (Ca(OH) 2(aq) ), which reacts with carbon dioxide to form calcium carbonate, and can react again with carbon dioxide and calcium carbonate to form calcium bicarbonate, achieving the effect of carbon capture.

[0031] The first-stage carbon dioxide capture module 11 is arranged above the second-stage carbon dioxide capture module 12. The waste gas enters the air inlet 122 of the second-stage carbon dioxide capture module 12 after the water mist mixing reaction in the first-stage carbon dioxide capture module 11. The carrier solution 126 (containing calcium carbonate, aqueous solution of calcium hydroxide and water) after the water mist mixing reaction naturally flows down to the water tank 120 of the second-stage carbon dioxide capture module 12, and the first pump 111 of the first-stage carbon dioxide capture module 11 is used to transport the carrier solution 126 in the water tank 120 of the second-stage carbon dioxide capture module 12 to the nozzles 1121 of the solution pipeline 112. Therefore, the first-stage carbon dioxide capture module 11 does not need to be provided with a separate water tank. Furthermore, the included angle θ between the water inlet partition plate 125 and the horizontal plane is between 30 degrees and 90 degrees, which is used to collect calcium carbonate more efficiently.

[0032] The carbon dioxide capture device 1 further includes: an electric control module 16, which includes first to third sensing components 161, 162, 163, a frequency converter 164, and a monitoring and display interface 165. The first sensing component 161 detects the changes in the carbon dioxide concentration, temperature, and flow rate of the waste gas introduced into the intake duct 14, and then uses the frequency converter 164 to modulate the frequency of the first pump 111 to adjust the water mist reaction area of the nozzles 1121 in the solution pipeline 112, or modulate the frequency of the second pump 121 to adjust the intake air flow rate of the intake port 122, ensuring that the capture and emission reduction mechanism operates within the optimized working conditions range and maintaining a stable reaction. By monitoring the carbon dioxide concentration and flow rate of the intake duct 14 and the exhaust duct 15 with the first and second sensing components 161 and 162, the carbon dioxide capture amount and the device energy consumption information are indirectly converted. And, the third sensing component 163 is a pH value sensing component disposed in the water tank 120. When the pH value is greater than a predetermined threshold (for example, pH value = 10), an indicator for replacing the carrier solution 126 is given.

[0033] Figure 3 Schematic cross-sectional view of the carbon dioxide capture device according to the second embodiment of the present invention. The carbon dioxide capture device 1' of the second embodiment is generally similar to the carbon dioxide capture device 1 of the first embodiment, and the same components are labeled with the same reference numerals. Please refer to Figure 3 , the main differences between the carbon dioxide capture devices 1' and 1 of the second and first embodiments are: the carbon dioxide capture device 1' further includes: a third-stage carbon dioxide capture module 13, configured in the exhaust duct 15, for performing multiple water mist mixing on the waste gas (referring to the waste gas that has passed through the second-stage carbon dioxide capture module 12), where an aqueous calcium hydroxide solution (Ca(OH) 2(aq) ) is still used as the carbon dioxide capture carrier. The third-stage carbon dioxide capture module 13 includes: a third pump 131 and another solution pipeline 132, and the another solution pipeline 132 has a plurality of nozzles 1321. The nozzles 1321 are located in the exhaust duct 15, and the third pump 131 is used to transport the carrier solution 126 to the nozzles 1321 of the another solution pipeline 132 for generating a water mist mixing reaction. Similar to the solution pipeline 112 and the nozzles 1121 described above, according to the actual operating conditions and capture efficiency, the solution pipeline 132 and the nozzles 1321 may also have a configuration and a setting number different from Figure 3 those shown in the drawing.

[0034] The carbon dioxide capture device 1' may further include a blower 17 and an exhaust fan 18. The blower 17 is disposed at the inlet 141 of the intake duct 14 and is connected to the intake duct 14 to supply a mixed gas at a pressure higher than atmospheric pressure into the intake duct 14. And the exhaust fan 18 is disposed at the outlet 151 of the exhaust duct 15 and is connected to the exhaust duct 15 to provide an exhaust environment at a pressure lower than atmospheric pressure.

[0035] Figure 4 It is a block diagram of a carbon dioxide capture device and an exhaust gas emission treatment device in an embodiment of the present invention. Please refer to Figure 4 The carbon dioxide capture devices 1, 1' may be connected in series to an exhaust gas emission treatment device 2, such as an electrostatic adsorption device, an oil fume water washing device, or a volatile organic compound (VOC) gas washing device.

[0036] Figure 5 It is a step flow chart of a carbon dioxide capture method in an embodiment of the present invention. Please refer to Figure 5 In step S1, multiple water mist mixing operations are performed on an exhaust gas to achieve a first-stage carbon dioxide capture reaction, where an aqueous calcium hydroxide solution (Ca(OH) 2(aq) ) is used as the first-stage carbon dioxide capture carrier; and in step S2, the carrier solution after the multiple water mist mixing operations is used to perform aeration water washing on the exhaust gas to achieve a second-stage carbon dioxide capture reaction.

[0037] The carbon dioxide capture device and method of the present invention use an aqueous calcium hydroxide solution that is easy to operate, has low chemical hazards, and is low-cost as a carbon dioxide capture carrier, and are combined with the device mechanism to sequentially perform a water mist mixing reaction and an aeration water washing reaction between the exhaust gas (such as process exhaust gas) and the aqueous calcium hydroxide solution. Through this dual reaction mechanism, the reaction between the aqueous calcium hydroxide solution and the target carbon dioxide gas can be enhanced to improve the carbon dioxide capture efficiency. Furthermore, the carbon dioxide capture device can be connected in series with exhaust gas emission treatment devices such as electrostatic adsorption devices, oil fume water washing devices, or volatile organic compound (VOC) gas washing devices before and after according to the environmental protection requirements for the emission of process exhaust gas, achieving system composite functions and enhancing the market value of the technical device. In addition, in response to changes in the carbon dioxide concentration, temperature, and flow rate of the intake gas at the inlet of the intake duct where the exhaust gas is discharged, the sensing of the carbon dioxide concentration, temperature, and flow rate of the intake gas can also be combined, and then the area of the water mist reaction and the flow rate of the water washing aeration can be adjusted to ensure that the carbon dioxide capture mechanism operates within the optimized working condition range and maintains a stable reaction.

[0038] In summary, the above only describes the preferred embodiments or examples of the technical means adopted by the present invention to present the solution to the problem, and is not used to limit the scope of implementation of the present invention patent. That is, all that conforms to the literal meaning of the scope of the present invention patent application, or equivalent changes and modifications made according to the scope of the present invention patent, are covered by the scope of the present invention patent.

Claims

1. A carbon dioxide capture device, characterized in that: include: an air intake duct and an exhaust duct; a first carbon dioxide capture module, disposed in the air intake duct, for performing a water mist mixing reaction, wherein a calcium hydroxide aqueous solution is used as a carbon dioxide capture carrier; as well as a second carbon dioxide capture module, disposed below the air inlet pipe, the first carbon dioxide capture module and the exhaust pipe, and used for performing an aeration and water washing reaction; One of the exhaust gases enters through the air inlet pipe, is firstly mixed with multiple water mists by the first carbon dioxide capture module, then aerated and washed by the second carbon dioxide capture module, and then discharged through the exhaust pipe.

2. The carbon dioxide capture device according to claim 1, characterized in that The first-stage carbon dioxide capture module includes: a first pump and a solution pipeline, the solution pipeline has a plurality of nozzles, the plurality of nozzles are located in the air inlet pipe, and the first pump is used to transport a carrier solution to the plurality of nozzles of the solution pipeline; the second-stage carbon dioxide capture module includes a water tank, a second pump, an air inlet, a water inlet, and a spray outlet, the carrier solution is arranged in the water tank, the water inlet is arranged below a liquid level of the carrier solution, and the second pump is connected to the air inlet, the water inlet and the spray outlet, and is used to mix the exhaust gas entering the air inlet and the carrier solution entering the water inlet and transport them to the spray outlet.

3. The carbon dioxide capture device according to claim 2, characterized in that: The first carbon dioxide capture module is arranged above the second carbon dioxide capture module. The exhaust gas enters the air inlet of the second carbon dioxide capture module after the water mist mixing reaction of the first carbon dioxide capture module. The carrier solution after the water mist mixing reaction naturally flows down to the water tank of the second carbon dioxide capture module, and the first pump of the first carbon dioxide capture module is used to transport the carrier solution in the water tank of the second carbon dioxide capture module to the multiple nozzles of the solution pipeline.

4. The carbon dioxide capture device according to claim 1, characterized in that It also includes: a third carbon dioxide capture module, which is arranged in the exhaust pipe and is used for multi-channel water mist mixing of the exhaust gas, wherein the calcium hydroxide aqueous solution is still used as a carbon dioxide capture carrier.

5. The carbon dioxide capture device according to claim 2, characterized in that: The water tank is provided with a water inlet baffle for isolating the communication between the air inlet pipe and the air outlet pipe.

6. The carbon dioxide capture device according to claim 1, characterized in that: It also includes: at least one of a blower and an exhaust fan, the blower is connected to the air intake duct to provide a mixed gas with a pressure higher than an atmospheric pressure to enter the air intake duct; and the exhaust fan is connected to the exhaust duct to provide an exhaust environment with a pressure lower than an atmospheric pressure.

7. The carbon dioxide capture device according to claim 2, characterized in that: The invention further comprises: an electronic control module, which comprises first to third sensing components and a frequency converter, wherein the first sensing component detects the changes in the concentration, temperature and flow rate of carbon dioxide contained in the exhaust gas introduced into the intake pipe, and then uses the frequency converter to modulate the first pump frequency to adjust the water mist reaction area of ​​the multiple nozzles of the solution pipeline, or modulates the second pump frequency to adjust the intake flow rate of the air inlet; the first and second sensing components are used to monitor the carbon dioxide concentration and flow rate of the intake pipe and the exhaust pipe, and indirectly convert the carbon dioxide capture amount and the energy consumption information of the device; and the third sensing component is a pH value sensing component arranged in the water tank, and when the pH value is greater than a predetermined threshold value, the indicator of replacing the carrier solution is carried out.

8. The carbon dioxide capture device according to claim 2, characterized in that: A ventrilo structure is formed between the second pump, the air inlet and a water inlet, and the air inlet generates a negative pressure suction effect through the ventrilo structure.

9. The carbon dioxide capture device according to claim 1, characterized in that: The carbon dioxide capture device is serially connected to a waste gas emission treatment device, and the waste gas emission treatment device includes one of an electrostatic adsorption device, a fume water washing device and a volatile organic compound gas washing device.

10. A method for capturing carbon dioxide, characterized in that: The following steps are involved: A first carbon dioxide capture reaction is achieved by subjecting a waste gas to multiple water mist mixing, wherein a calcium hydroxide aqueous solution is used as a carbon dioxide capture carrier; and The carrier solution mixed with the multiple water mists is used to aerate and wash the waste gas to achieve a second carbon dioxide capture reaction.

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