Electrochemical calcium cycle carbon dioxide trapping system based on calcium carbonate and calcium hydroxide

Abstract

The invention discloses an electrochemical calcium cycle carbon dioxide trapping system based on calcium carbonate and calcium hydroxide. The system comprises a calcium hydroxide generation module, a carbonation module and a carbon dioxide treatment module. Firstly, acid and alkali are generated in the calcium hydroxide generation module by adopting an electrochemical method, calcium carbonate is decomposed by the generated acid to obtain calcium ions and release carbon dioxide, and the carbon dioxide is dried, compressed and stored by the carbon dioxide treatment module. And reacting the calcium ions with the generated alkali to obtain calcium hydroxide. Calcium hydroxide can be used as a solid carbon dioxide adsorbent, and carbon dioxide is captured in the carbonation module to obtain calcium carbonate. Therefore, electrochemical calcium cycle carbon dioxide capture is realized. The method is low-carbon, environment-friendly, high in energy efficiency, simple and feasible, and beneficial to solving the problems of energy consumption and pollution of carbon dioxide capture.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture, and more specifically to an electrochemical calcium cycle carbon dioxide capture system based on calcium carbonate and calcium hydroxide. Background Technology

[0002] Carbon dioxide (CO2) is a major greenhouse gas contributing to global warming and ocean acidification, and the large-scale application of CO2 capture technology is of great significance for climate regulation. Traditional calcium cycle capture technology has advantages such as abundant raw material reserves, high adsorption capacity, and low cost. However, this cycle of calcium carbonate and calcium oxide requires the combustion of fossil fuels to provide high-temperature conditions, and also requires additional air separation equipment to produce pure oxygen to facilitate the cycle.

[0003] Based on this, this patent innovatively employs an electrochemical method by utilizing the recycling of calcium hydroxide and calcium carbonate to capture and convert carbon at low temperatures, which helps to further reduce the high energy consumption of carbon dioxide capture and reduce air pollution problems. Summary of the Invention

[0004] In order to reduce energy consumption and solve the air pollution problem caused by carbon dioxide, the purpose of this invention patent is to achieve carbon capture at low temperature through the cyclic conversion of electrochemical calcium carbonate and calcium hydroxide.

[0005] The technical solution adopted by this invention to solve its technical problem is: an electrochemical calcium cycle carbon dioxide capture system based on calcium carbonate and calcium hydroxide, including a calcium hydroxide generation module, a carbonation module, and a carbon dioxide treatment module; the calcium hydroxide generation module is used to convert calcium carbonate into calcium hydroxide adsorbent and obtain pure carbon dioxide gas, the carbonation module is used to capture carbon dioxide gas in various scenarios including air and industrial flue gas, and the carbon dioxide treatment module is used to treat the captured carbon dioxide gas.

[0006] The specific technical solution is as follows: This low-temperature carbon cycle system first generates acid and alkali solutions in the calcium hydroxide generation module by electrolyzing a salt solution in an acid-base electrolytic cell. The acid solution is then pumped into the calcium carbonate decomposition unit via a first peristaltic pump to obtain high-concentration carbon dioxide. This carbon dioxide is then stored in the carbon dioxide treatment module through dehumidification and compression for further conversion and utilization. The solid-liquid mixture obtained from the calcium carbonate decomposition unit passes through a first solid-liquid separator, with the separated liquid being introduced into the calcium hydroxide generation unit. Simultaneously, an alkali solution is pumped into the calcium hydroxide generation unit via a second peristaltic pump, resulting in a second solid-liquid mixture. This mixture is then separated by a second solid-liquid separator to obtain calcium hydroxide adsorbent and circulating electrolyte. The calcium hydroxide adsorbent enters the carbonation module to capture low-concentration carbon dioxide, and the recovered calcium carbonate is then returned to the calcium hydroxide generation module for decarbonization.

[0007] Preferably, the calcium hydroxide generation module consists of an acid-base generation electrolytic cell, a calcium carbonate decomposition device, a calcium hydroxide generation device, a first peristaltic pump, a second peristaltic pump, a first solid-liquid separator, a second solid-liquid separator, gas, liquid, and solid pipelines.

[0008] Preferably, the acid-base generating electrolytic cell is composed of components such as an anode, a cathode, and a diaphragm.

[0009] Preferably, the cathode and anode electrodes are made of metallic materials, carbon materials, etc., including pure metals, metal derivatives, metal-organic frameworks, and various composite materials.

[0010] Preferably, the electrolyte may be an aqueous solution of one or more of the following: nitrates, nitrites, hydrochlorides, carbonates, bicarbonates, perchlorates, hypochlorites, perbromates, hypobromates, iodates, periodates, sulfates, thiosulfates, phosphates, etc., of lithium, sodium, potassium, cesium, ammonium, etc.

[0011] Preferably, the carbonation module has an inlet for supplying carbon dioxide gas from various scenarios such as air and industrial flue gas, an outlet for discharging the captured gas, an inlet for supplying calcium hydroxide adsorbent, and an outlet for discharging the calcium carbonate obtained after adsorption.

[0012] Preferably, the carbon dioxide processing module consists of a condenser, a compressor, and a storage tank. The condenser is used for drying carbon dioxide, the compressor is used for compressing carbon dioxide, and the storage tank is used for storing carbon dioxide.

[0013] This method has the following beneficial effects: (1) The present invention can use an electrochemical method to cycle calcium carbonate and calcium hydroxide, which has lower energy consumption and a greener process compared to the cycle mode of calcium carbonate and calcium oxide. (2) The salt solution and calcium recycling agent in this invention can be recycled. The deactivated calcium hydroxide adsorbent can continue to participate in the preparation of pharmaceutical and industrial products. The high-purity carbon dioxide gas obtained by decomposing calcium carbonate can be further converted and utilized without any secondary pollution. (3) The present invention uses the calcium cycle method for carbon dioxide capture. The raw material is calcium carbonate, which is widely available and the method is economical. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a schematic diagram of the electrochemical calcium carbonate and calcium hydroxide cycle for capturing carbon dioxide.

[0016] Wherein: 1-Calcium hydroxide generation module, 2-Carbonation module, 3-Carbon dioxide treatment module, 11-Acid-base generation electrolytic cell, 12-Calcium carbonate decomposition device, 13-Calcium hydroxide generation device, 14-First solid-liquid separator, 15-Second solid-liquid separator, 16-First peristaltic pump, 17-Second peristaltic pump, 21-Air inlet, 22-Air outlet, 23-Feed inlet, 24-Discharge outlet, 31-Condenser, 32-Compressor, 33-Gas storage tank.

[0017] Figure 2 The images show XRD patterns of calcium hydroxide and calcium carbonate samples; from top to bottom, they represent the extracted calcium hydroxide sample and the calcium carbonate sample obtained after capturing carbon dioxide. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] This invention discloses an electrochemical calcium-cycle carbon dioxide capture system based on calcium carbonate and calcium hydroxide, as illustrated in the diagram. Figure 1 As shown, it includes a calcium hydroxide generation module 1, a carbonation module 2, a carbon dioxide treatment module 3, and gas, liquid, and solid pipelines connected in sequence. The calcium hydroxide generation module 1 is used to obtain calcium hydroxide adsorbent and pure carbon dioxide gas. The carbonation module 2 is used to capture carbon dioxide, and the carbon dioxide treatment module 3 is used to treat the captured carbon dioxide.

[0020] The calcium hydroxide generation module 1 includes an acid-base generation electrolytic cell 11, a calcium carbonate decomposition device 12, a calcium hydroxide generation device 13, a first solid-liquid separator 14, a second solid-liquid separator 15, a first peristaltic pump 16, and a second peristaltic pump 17. The acid-base generation electrolytic cell 11 is used to convert a soluble salt solution into an acid solution and an alkali solution. The calcium carbonate decomposition device 12 is used to decompose the raw material calcium carbonate to obtain a first solid-liquid mixture, while releasing pure carbon dioxide gas. The calcium hydroxide generation device 13 is used to combine with the alkali solution to obtain a calcium hydroxide adsorbent. The first solid-liquid separator 14 is used to separate the first solid-liquid mixture to obtain a calcium ion solution. The second solid separator 15 is used to separate the circulating electrolyte and the calcium hydroxide solid adsorbent. The first peristaltic pump 16 is used to pump the acid solution into the calcium carbonate decomposition device 12, and the second peristaltic pump 17 is used to pump the alkali solution into the calcium hydroxide generation device 13.

[0021] The carbonation module 2 includes an air inlet 21, an air outlet 22, a feed inlet 23, and a discharge outlet 24. The air inlet 21 is used to transport carbon dioxide gas from various scenarios, such as air and industrial flue gas. The air outlet 22 is used to discharge the captured carbon dioxide gas. The feed inlet 23 is used to transport calcium hydroxide adsorbent, and the discharge outlet 24 is used to discharge the calcium carbonate obtained after adsorption. The carbon dioxide treatment module 3 includes a condenser 31, a compressor 32, and a gas storage tank 33. The condenser 31 is used to dry the carbon dioxide gas, the compressor 32 is used to compress the carbon dioxide gas, and the gas storage tank 33 is used to store the carbon dioxide gas.

[0022] The carbonation module 2 includes an air inlet 21, an air outlet 22, a feed inlet 23, and a discharge outlet 24. The air inlet 21 is used to transport carbon dioxide gas from various scenarios, such as air and industrial flue gas. The air outlet 22 is used to discharge the captured carbon dioxide gas. The feed inlet 23 is used to transport calcium hydroxide adsorbent, and the discharge outlet 24 is used to discharge the calcium carbonate obtained after adsorption. The carbon dioxide treatment module 3 includes a condenser 31, a compressor 32, and a gas storage tank 33. The condenser 31 is used to dry the carbon dioxide gas, the compressor 32 is used to compress the carbon dioxide gas, and the gas storage tank 33 is used to store the carbon dioxide gas.

[0023] The carbon dioxide capture system uses calcium carbonate as raw material. A salt solution is added, and an electric current is applied. Under the action of anode and cathode catalysts, the salt solution is converted into acid and alkali solutions by the acid-base generation electrolytic cell 11. These solutions are then pumped into the calcium carbonate decomposition device 12 and the calcium hydroxide generation device 13 by the first peristaltic pump 16 and the second peristaltic pump 17, respectively. In the calcium carbonate decomposition device 12, the acid reacts with calcium carbonate to obtain a first solid-liquid mixture. This mixture is separated by the first solid-liquid separator 14 to obtain liquid, which then enters the calcium hydroxide generation device 13. This liquid combines with the alkali solution to obtain a second solid-liquid mixture. The solid and liquid are separated by the second solid-liquid separator 15. The liquid is recycled back into the acid-base generation electrolytic cell 11, while the solid acts as an adsorbent, entering the carbonation module 2 through the feed inlet 23. Gas containing carbon dioxide enters the carbonation module 2 through the inlet 21, where the carbon dioxide is adsorbed by the solid adsorbent. The solid in the reactor then enters the calcium carbonate decomposition device 12 through the outlet 24 for decarbonation. The treated gas is discharged through the outlet 22. In the calcium carbonate decomposition device 12, the impurity-free carbon dioxide gas produced by the decomposition of calcium carbonate is stored in the gas storage tank 33 through the condenser 31 and the compressor 32. The high-purity carbon dioxide obtained can be further coupled with conversion and utilization technologies. The salt solution in the reaction process can be continuously circulated in the system. Calcium carbonate and calcium hydroxide, as the carbon dioxide capture medium, can also be continuously circulated in the system.

[0024] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0026] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. This invention relates to an electrochemical calcium-cycle carbon dioxide capture system based on calcium carbonate and calcium hydroxide, characterized in that, First, an acid and a base are generated using an electrochemical method. The acid decomposes calcium carbonate to obtain calcium ions and release carbon dioxide, which is then dried, compressed, and stored. The calcium ions react with the generated base to form calcium hydroxide. Calcium hydroxide can then be used as a solid carbon dioxide adsorbent to capture carbon dioxide, yielding calcium carbonate. This process achieves electrochemical calcium-cycle carbon dioxide capture.

2. The electrochemical calcium-cycle carbon dioxide capture system according to claim 1, characterized in that, It includes a calcium hydroxide generation module, a carbonation module, a carbon dioxide treatment module, or one or more of these modules. The calcium hydroxide generation module is used to decompose and convert calcium carbonate into calcium hydroxide adsorbent and carbon dioxide gas. The carbonation module uses calcium hydroxide to capture carbon dioxide. The carbon dioxide treatment module is used to treat the generated carbon dioxide.

3. The calcium hydroxide generating module according to claim 2, characterized in that, This includes, but is not limited to, an acid-base generation electrolytic cell, a calcium carbonate decomposition device, and a calcium hydroxide generation device. The acid-base generation electrolytic cell is used to convert a salt solution into an acidic and an alkaline solution. The calcium carbonate decomposition device is used to react calcium carbonate with the generated acid to produce calcium ions, while simultaneously releasing carbon dioxide gas. The calcium hydroxide generation device is used to react calcium ions with the generated alkali to produce a calcium hydroxide adsorbent. All devices are connected by pipelines.

4. The carbonation module according to claim 2, characterized in that, Calcium hydroxide is used to adsorb and capture carbon dioxide in various gases, such as incoming air and industrial flue gas, and is then converted into calcium carbonate.

5. The carbon dioxide treatment module according to claim 2, characterized in that, The captured carbon dioxide gas is processed, including but not limited to drying, compression, storage, and utilization.

6. The acid-base generation electrolytic cell according to claim 3, characterized in that, Including but not limited to alkaline electrolyzers, proton exchange membrane electrolyzers, anion exchange membrane electrolyzers, bipolar membrane electrolyzers, etc., which are composed of components such as anodes, cathodes, and diaphragms, and can produce acids and alkalis under the action of electric current.

7. The acid-base generation electrolytic cell according to claim 3, characterized in that, The anode and cathode electrodes include, but are not limited to, those made of pure metals, metal derivatives, metal-organic frameworks, carbon materials, and various composite materials.

8. The acid-base generation electrolytic cell according to claim 3, characterized in that, The electrolyte may be an aqueous solution of one or more of the following: nitrates, nitrites, hydrochlorides, carbonates, bicarbonates, perchlorates, hypochlorites, perbromates, hypobromates, iodates, periodates, sulfates, thiosulfates, and phosphates of lithium, sodium, potassium, cesium, and ammonium.

9. The calcium carbonate decomposition apparatus according to claim 3, characterized in that, The calcium carbonate raw material is placed in it and reacts with the acid obtained by electrochemical reaction to obtain a calcium salt solution.

10. The calcium hydroxide generating apparatus according to claim 3, characterized in that, Calcium hydroxide adsorbent is obtained by reacting calcium salt solution with an electrochemically obtained alkaline solution.

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