Carbon dioxide trapping and sealing device based on alkali liquor absorption method

Abstract

The utility model provides a carbon dioxide capturing and sealing device based on an alkali liquor absorption method. The carbon dioxide capturing and sealing device solves the problems that an existing chemical solvent absorption process device is large in energy consumption, low in absorption efficiency, large in absorbent consumption and not prone to regeneration. The device comprises a spraying reaction unit, an absorbent regeneration unit and a sealing unit, the spraying reaction unit is used for spraying alkali liquor and is in reverse contact with the flue gas to absorb carbon dioxide; the absorbent regeneration unit is used for regenerating the absorbed alkali liquor for reuse, and the sealing unit is used for sealing solid products in the absorbent regeneration unit; wherein the sealing unit can be replaced by a desorption unit and a carbon dioxide storage tank, and the desorption unit is used for heating and decomposing solid products, desorbing carbon dioxide and storing the carbon dioxide in the carbon dioxide storage tank.

Description

Technical Field

[0001] The utility model belongs to the technical field of carbon dioxide gas capture and sealing, and specifically relates to a carbon dioxide capture and sealing device based on an alkali solution absorption method. Background Art

[0002] With the gradual deepening of industrialization, how to effectively curb carbon dioxide emissions has become an urgent problem that needs to be solved. As one of the main sources of greenhouse gases, carbon dioxide remains in the atmosphere for a long time and causes great harm. Its emission reduction plays a major role in addressing climate change and building an ecological civilization on Earth.

[0003] Carbon dioxide capture technologies can be divided into the following categories: pre-combustion capture, post-combustion capture, oxyfuel combustion, and industrial process capture. At present, post-combustion control technology has received extensive attention, and treatment methods are also changing with each passing day. The main capture methods include solvent absorption, chemical adsorption, physical adsorption, and membrane separation.

[0004] At present, the solvent absorption method can be divided into physical absorption method and chemical absorption method. For the chemical solvent absorption system, the raw gas and chemical solvent (such as alkali solution) are used to react chemically in the absorption tower. The solution after absorbing CO2 is called rich liquid. The rich liquid is converted into products to realize carbon dioxide storage, or enters the desorption tower to decompose CO2 by heating to achieve the purpose of separating and capturing CO2.

[0005] However, the existing mature and stable chemical solvent absorption process (such as amine solution absorption process) consumes a lot of energy and has a low absorption efficiency. A large amount of energy is needed to make up for the heat and pressure required in the carbon dioxide capture process. Most of these energy sources come from fossil fuels and will also produce carbon dioxide emissions, which is inconsistent with the purpose of capture. In addition, the absorbent is consumed a lot and is not easy to regenerate. In view of this, the utility model believes that it is necessary to further improve the existing chemical solvent absorption process equipment. Summary of the invention

[0006] The utility model aims to solve the problems of large energy consumption, low absorption efficiency, large absorbent consumption and difficulty in regeneration of existing chemical solvent absorption process equipment, and to provide a carbon dioxide capture and storage device based on alkali solution absorption method.

[0007] The inventive concept of the utility model:

[0008] In view of the problem of low absorption efficiency of existing chemical solution absorption process equipment when absorbing carbon dioxide, the utility model provides a carbon dioxide capture and storage device with simple process, convenient operation, and easy regeneration of absorbent, so as to improve the operation efficiency of the capture device. It is proposed to use alkaline solution (sodium hydroxide, potassium hydroxide, etc.) as the absorbent, which has low cost and mild reaction conditions and does not require additional heat and pressure; carbon dioxide is stored through product conversion, and the separation agent (calcium oxide-based materials 16-44 US dollars / ton) is nearly half the cost of carbon capture than amine washing technology (32-80 US dollars / ton), or further use a high-temperature reactor to achieve separation and purification of carbon dioxide for resource utilization; at the same time, the regenerated absorbent is recycled through solid-liquid separation to reduce the capture cost.

[0009] To achieve the above purpose, the technical solution provided by the utility model is:

[0010] A carbon dioxide capture and storage device based on an alkaline solution absorption method, characterized in that:

[0011] It includes a spray reaction unit, an absorbent regeneration unit, a desorption unit and a carbon dioxide storage tank;

[0012] The spray reaction unit includes a spray reactor and a spray assembly;

[0013] The spray reactor is provided with a flue gas inlet pipe near the bottom, an outlet pipe at the top, a liquid inlet pipe near the top, and a liquid outlet pipe at the bottom; the flue gas inlet pipe, outlet pipe, liquid inlet pipe, and liquid outlet pipe are all provided with switch valves;

[0014] The spray assembly comprises a plurality of groups of sprayers arranged in sequence from top to bottom in the spray reactor, each group of sprayers is connected to the liquid inlet pipe, and is used to spray alkali solution into the spray reactor, and reversely contact with the flue gas entering the spray reactor to absorb carbon dioxide;

[0015] The absorbent regeneration unit includes a reaction tank and an automatic separation component;

[0016] The top of the reaction tank is provided with a feed pipe for the separation agent to enter, and the bottom is provided with a regenerated absorbent outlet; a reaction liquid inlet and a material outlet are provided on the wall of the reaction tank; the reaction liquid inlet is connected with the liquid outlet pipe of the spray reactor; the regenerated absorbent outlet is connected with the liquid inlet pipe of the spray reactor through a reflux pipe, and a pump for pumping the regenerated absorbent back to the spray reactor is provided on the reflux pipe, so as to realize the regeneration and recycling of the absorbent, and the reflux pipe is provided with a switch valve at a position close to the reaction liquid inlet and at a position close to the feed pipe;

[0017] The automatic separation assembly includes a lifting track, a filter conveyor and a control unit, which can separate the solid and liquid after the reaction in the reaction tank and transport the solid product to the next unit;

[0018] The lifting track includes a first track and a second track, the two tracks are installed on two opposite walls in the reaction tank, and the upper end of the first track is close to the material outlet;

[0019] The filter conveyor comprises a rolling filter conveyor belt and a material conveying pipe; the two sides of the rolling filter conveyor belt are respectively installed on two tracks, and when it rises to the highest point, the side installed on the second track is higher than the side installed on the first track, that is, the filter conveyor is inclined so that the solid product can smoothly enter the material conveying pipe; the material conveying pipe passes through the material outlet and is obliquely installed on the wall of the reaction tank, and a stop valve is arranged on it;

[0020] The control component is used to control the rolling operation of the rolling filter conveyor belt and the lifting movement on the lifting track, and transport the solid products in the reaction tank to the sealing unit through the material conveying pipe. In this way, the carbon dioxide is reused and sealed in the form of converted solid products.

[0021] Furthermore, the storage unit may also be replaced by a desorption unit and a carbon dioxide storage tank;

[0022] The desorption unit includes a high-temperature reactor for decomposing solid products; the outlet of the material conveying pipe is connected to the inlet of the high-temperature reactor; the outlet of the high-temperature reactor is connected to the carbon dioxide storage tank through a gas pipeline, and a switch valve is provided on the gas pipeline, so that carbon dioxide can be captured and sealed in the form of gas, and the separation agent can be regenerated and recycled.

[0023] Furthermore, the sprayer includes a cross-shaped spray arm and a plurality of spray heads evenly distributed on the spray arm. The number of sprayers in the spray reactor and the number of spray heads on each sprayer can be determined according to the size of the spray reactor.

[0024] Furthermore, in order to make the sodium hydroxide solution spray more uniformly and promote the maximum contact between the sodium hydroxide solution and carbon dioxide to improve the absorption efficiency of carbon dioxide, adjacent sprayers are staggered in the spray reactor.

[0025] Furthermore, in order to improve the absorption efficiency of the sodium hydroxide solution, the liquid outlet pipe of the spray reactor is also connected to the inlet of the pump through a pipeline. After the sodium hydroxide solution absorbs carbon dioxide for the first time, it can be returned to the spray reactor for reabsorption and then transported to the absorbent regeneration unit for regeneration.

[0026] Furthermore, the reaction liquid inlet and the material outlet are provided on two opposite walls of the reaction tank, and the material outlet is arranged near the middle of the wall, and the reaction liquid inlet is arranged near the top of the wall.

[0027] Further, the spray reactor is cylindrical;

[0028] The spray arm is adapted to the radial dimension of the reactor.

[0029] Furthermore, the spray reactor and the reaction tank are both made of stainless steel.

[0030] Further, the alkali solution is a sodium hydroxide solution or a potassium hydroxide solution;

[0031] The separating agent is calcium oxide.

[0032] The advantages of the utility model are:

[0033] 1. The utility model provides a carbon dioxide capture and storage device based on the alkali solution absorption method, which can effectively solve the problems of large energy consumption, low absorption efficiency, large absorbent consumption and difficult regeneration of existing chemical solvent absorption process equipment. A spray reactor is provided with multiple layers of sprayers, which are staggered and evenly distributed. The absorbent is evenly distributed through uniformly distributed nozzles so that the contact area with carbon dioxide can be maximized by uniform spraying; and the solution in the reaction tank (i.e., the regenerated absorbent) is refluxed to the spray reactor through a pump for regeneration, and the solid product can be directly sealed as a product or decomposed by a desorption unit to collect dry CO2. The decomposed solid product can continue to be used as a separation agent to fully realize regeneration.

[0034] 2. In the utility model, the solidification and sealing of carbon dioxide can be achieved through the spray reactor and the reaction tank, and a high-temperature reactor can be added to achieve the separation and purification of carbon dioxide, further utilizing carbon dioxide as a resource, and the sealing form is diversified and can be selected according to needs.

[0035] 3. The capture device designed based on the alkali solution absorption method of the utility model has a simple structure and is easy to manufacture, and both the absorbent and the separation agent can be regenerated and reused, so the operating cost is low.

[0036] 4. The utility model adopts alkaline solution as absorbent and calcium oxide as separation agent, so that the absorbent can be regenerated and recycled, and the service life is long. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the structure of the capture and sealing device of the utility model;

[0038] Figure 2 It is a schematic diagram of the structure of the sprayer in the capture and sealing device of the utility model;

[0039] Figure 3 It is a structural schematic diagram of the filter screen transmission component in the capture and sealing device of the utility model.

[0040] The reference numerals are as follows:

[0041] 1- spray reactor, 2- flue gas inlet, 3- outlet, 4- first switch valve, 5- second switch valve, 6- sprayer, 7- nozzle, 8- third switch valve, 9- liquid outlet pipe, 10- reaction tank, 11- rolling filter conveyor belt, 12- fourth switch valve, 13- reflux pipeline, 14- pump, 15- liquid inlet pipe, 16- feed pipe, 17- fifth switch valve, 18- sixth switch valve, 19- high temperature reactor, 20- seventh switch valve, 21- carbon dioxide storage tank, 22- lifting rail, 23- material conveying pipe, 24- stop valve, 25- eighth switch valve, 26- ninth switch valve, 27- control part. DETAILED DESCRIPTION

[0042] The following is a further detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments:

[0043] Figure 1 As shown, a carbon dioxide capture and storage device based on an alkaline solution absorption method includes a spray reaction unit, an absorbent regeneration unit, a desorption unit and a carbon dioxide storage tank.

[0044] The spray reaction unit includes a spray reactor and a spray assembly. The spray reactor is cylindrical, and a smoke inlet pipe connected to a smoke source (i.e., a smoke generating device) is arranged near the bottom, on which a first switch valve is arranged; an outlet pipe for discharging smoke after capturing carbon dioxide is arranged at the top of the spray reactor, on which a second switch valve is arranged; a liquid inlet pipe is arranged near the top of the spray reactor, which is used to transport sodium hydroxide solution into the spray reactor, on which a ninth switch valve is arranged; a liquid outlet pipe is arranged at the bottom of the spray reactor, on which a third switch valve is arranged. The spray assembly includes multiple groups of sprayers arranged in the spray reactor from top to bottom, and the multiple groups of sprayers are connected to the liquid inlet pipe for spraying sodium hydroxide solution into the spray reactor; the sprayer includes a cross-shaped spray arm and multiple nozzles evenly distributed on the spray arm. The number of sprayers in the spray reactor and the number of nozzles on each sprayer can be determined according to the size of the spray reactor. In this embodiment, three groups of sprayers are used; the spray arm is adapted to the radial size of the reactor. In order to make the sodium hydroxide solution spray more uniformly and maximize the contact between the sodium hydroxide solution and carbon dioxide to improve the absorption efficiency of carbon dioxide, adjacent sprayers are staggered in the spray reactor.

[0045] The absorbent regeneration unit includes a reaction tank and an automatic separation component. A feed pipe for calcium oxide (separating agent) to enter is arranged on the top of the reaction tank, a fifth switch valve is arranged on the feed pipe, and a regenerated absorbent outlet is arranged at the bottom; a reaction liquid inlet and a material outlet are arranged on two opposite walls of the reaction tank, wherein the material outlet is arranged near the middle of the wall, and the reaction liquid inlet is arranged near the top of the wall; the reaction liquid inlet is connected to the liquid outlet pipe of the spray reactor through a conveying pipeline, and a sixth switch valve is arranged near the reaction liquid inlet; the regenerated absorbent outlet is connected to the liquid inlet pipe of the spray reactor through a reflux pipeline, and a pump for pumping the regenerated absorbent back to the spray reactor is arranged on the reflux pipeline, so that the regeneration and recycling of the absorbent can be realized, and for the convenience of control, the reflux pipeline is respectively provided with a fourth switch valve and an eighth switch valve near the reaction liquid inlet and the feed pipe; in this way, there are two absorbent entry channels at the liquid inlet pipe, one is the original sodium hydroxide solution channel provided with the tenth switch valve, and the other is the reflux sodium hydroxide solution channel provided with the ninth switch valve.

[0046] The automatic separation component includes a lifting track, a filter conveyor and a control component. The lifting track includes a first track and a second track. The two tracks are installed on two opposite walls in the reaction tank, and the upper end of the first track is close to the material outlet. The filter conveyor includes a rolling filter conveyor belt and a material conveying pipe; the two sides of the rolling filter conveyor belt are respectively installed on the two tracks. When it rises to the highest point, the side installed on the second track is higher than the side installed on the first track, that is, the filter conveyor is inclined so that the solid product can smoothly enter the material conveying pipe; the material conveying pipe is installed obliquely on the wall of the reaction tank through the material outlet, and a stop valve is arranged on it. The control component is used to control the rolling operation of the rolling filter conveyor belt and the lifting and lowering movement on the lifting track, so as to transport the solid product in the reaction tank to the desorption unit through the material conveying pipe.

[0047] In order to improve the absorption efficiency of the sodium hydroxide solution, the liquid outlet pipe of the spray reactor is also connected to the inlet of the pump through a pipeline. After the sodium hydroxide solution absorbs carbon dioxide for the first time, it can be refluxed to the spray reactor for reabsorption and then transported to the absorbent regeneration unit for regeneration. In order to simplify the pipeline and facilitate control, the delivery pipeline can be connected to the reflux pipeline, and the connection point is located between the third switch valve and the sixth switch valve, and between the fourth switch valve and the pump.

[0048] The desorption unit includes a high-temperature reactor for decomposing solid products; the outlet of the material conveying pipe is connected to the inlet of the high-temperature reactor; the outlet of the high-temperature reactor is connected to the carbon dioxide storage tank through a gas pipeline, and a seventh switch valve is provided on the gas pipeline. In this way, carbon dioxide can be captured and sealed in the form of gas, and calcium oxide can also be regenerated and recycled.

[0049] The above-mentioned spray reactor and reaction tank are both made of stainless steel.

[0050] The capture principle of the utility model is:

[0051] During absorption, the flue gas enters the spray reactor, and the sodium hydroxide solution is sprayed through the spray assembly, which contacts the flue gas in reverse, so that the sodium hydroxide solution absorbs CO2 in the flue gas more efficiently (i.e., increases the amount of CO2 dissolved in the sodium hydroxide solution). The sodium hydroxide solution that has absorbed CO2 for the first time flows back to the spray reactor under the action of the pump, and is sprayed again for further reaction;

[0052] During sealing, the solution (sodium bicarbonate and sodium carbonate) after the reaction in the spray reactor is transported to the reaction tank, and the separation agent calcium oxide is added. The calcium oxide reacts with the reaction solution (sodium bicarbonate and sodium carbonate), absorbs the CO2 in the solution to form a calcium carbonate precipitate, which is collected, and the sodium hydroxide solution is regenerated. After solid-liquid separation by an automatic separation component, the regenerated sodium hydroxide solution is pumped back to the spray reactor for repeated use. The calcium carbonate precipitate collected so far can achieve the purpose of sealing carbon dioxide;

[0053] If further utilization for desorption is required, the calcium carbonate precipitate is sent to a high-temperature reactor. After heating and desorption, the precipitated CO2 is transported to a carbon dioxide storage tank through a gas pipeline for storage, thereby achieving the purpose of capturing carbon dioxide and utilizing CO2 as a resource. The calcium oxide remaining in the high-temperature reactor can be collected and utilized again.

[0054] The working process of the utility model is as follows:

[0055] Close all the switch valves of the device, start the sprayer in the spray reactor 1, open the ninth switch valve 26 to transport sodium hydroxide solution to the sprayer, and the sodium hydroxide solution is evenly sprayed through the nozzle 7. At the same time, open the first switch valve 4 and the second switch valve 5, and the flue gas enters the spray reactor 1 through the flue gas inlet pipe 2. The flue gas and the sodium hydroxide solution are in reverse contact to absorb carbon dioxide, and the reacted gas is discharged through the outlet 3; then open the third switch valve 8, the pump 14 and the eighth switch valve 25 to return the reacted solution to the spray reactor through the liquid outlet pipe 9, the reflux pipe, and the liquid inlet pipe 15 for spray absorption again; close the pump 14, open the sixth switch valve 18, and send the solution after the second reaction to the reaction tank 10. Afterwards, open the feed pipe 16 and add calcium oxide into the reaction tank 10 for reaction. The rolling filter conveyor belt 11 is lowered to the bottom of the reaction tank 10. After sufficient reaction, the rolling filter conveyor belt 11 is raised to the top of the lifting track through the control component 27 to separate the solid and liquid after the reaction. The fourth switch valve 12 and the pump 14 are opened to pump the regenerated sodium hydroxide solution back to the spray reactor through the reflux pipe 13 and the liquid inlet pipe 15 for spray absorption again; open the stop valve 24, start the rolling filter conveyor belt 11 to send the precipitate after the reaction to the high-temperature reactor 19 through the material conveying pipe 23, and precipitate CO2 through high temperature (800°C) decomposition. Open the seventh switch valve 20 to transport CO2 to the carbon dioxide storage tank 21 through the gas pipeline.

[0056] The above is a cyclic process for completing carbon dioxide capture and storage. By repeating the above process, carbon dioxide can be captured from flue gas.

[0057] The above description is only a specific implementation mode of the present utility model, but the protection scope of the present utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present utility model, and these modifications or substitutions should be included in the protection scope of the present utility model.

Claims

1. A carbon dioxide capture and storage device based on alkali solution absorption method, characterized in that: It includes a spray reaction unit, an absorbent regeneration unit and a sealing unit; The spray reaction unit includes a spray reactor and a spray assembly; The spray reactor is provided with a flue gas inlet pipe near the bottom, an outlet pipe at the top, a liquid inlet pipe near the top, and a liquid outlet pipe at the bottom; the flue gas inlet pipe, outlet pipe, liquid inlet pipe, and liquid outlet pipe are all provided with switch valves; The spray assembly comprises a plurality of groups of sprayers arranged in sequence from top to bottom in the spray reactor, each group of sprayers is connected to a liquid inlet pipe and is used to spray alkali solution into the spray reactor; The absorbent regeneration unit includes a reaction tank and an automatic separation component; The top of the reaction tank is provided with a feed pipe for the separation agent to enter, and the bottom is provided with a regenerated absorbent outlet; a reaction liquid inlet and a material outlet are provided on the wall of the reaction tank; the reaction liquid inlet is connected with the liquid outlet pipe of the spray reactor; the regenerated absorbent outlet is connected with the liquid inlet pipe of the spray reactor through a reflux pipe, and a pump for pumping the regenerated absorbent back to the spray reactor is provided on the reflux pipe, and a switch valve is provided at a position of the reflux pipe near the reaction liquid inlet and near the feed pipe; The automatic separation assembly includes a lifting track, a filter conveyor and a control component; The lifting track includes a first track and a second track, the two tracks are installed on two opposite walls in the reaction tank, and the upper end of the first track is close to the material outlet; The filter conveyor comprises a rolling filter conveyor belt and a material conveying pipe; the two sides of the rolling filter conveyor belt are respectively installed on two tracks, and the side installed on the second track is higher than the side installed on the first track; the material conveying pipe passes through the material outlet and is obliquely installed on the wall of the reaction tank, and a stop valve is arranged on it; The control component is used to control the rolling operation of the rolling filter conveyor belt and the lifting movement on the lifting track, so as to transport the solid product in the reaction tank to the sealing unit through the material conveying pipe.

2. The carbon dioxide capture and storage device according to claim 1, characterized in that: Replacing the storage unit with a desorption unit and a carbon dioxide storage tank; The desorption unit includes a high-temperature reactor for decomposing solid products; the outlet of the material conveying pipe is connected to the inlet of the high-temperature reactor; the outlet of the high-temperature reactor is connected to the carbon dioxide storage tank through a gas pipeline, and a switch valve is provided on the gas pipeline.

3. The carbon dioxide capture and storage device according to claim 1 or 2, characterized in that: The sprayer comprises a cross-shaped spray arm and a plurality of spray heads evenly distributed on the spray arm.

4. The carbon dioxide capture and storage device according to claim 3, characterized in that: Adjacent sprayers are arranged in a staggered manner in the spray reactor.

5. The carbon dioxide capture and storage device according to claim 4, characterized in that: The liquid outlet pipe of the spray reactor is also connected to the inlet of the pump through a pipeline.

6. The carbon dioxide capture and storage device according to claim 5, characterized in that: The reaction liquid inlet and the material outlet are arranged on two opposite walls of the reaction tank, and the material outlet is arranged near the middle of the wall, and the reaction liquid inlet is arranged near the top of the wall.

7. The carbon dioxide capture and storage device according to claim 6, characterized in that: The spray reactor is cylindrical; The spray arm is adapted to the radial dimension of the reactor.

8. The carbon dioxide capture and storage device according to claim 7, characterized in that: The spray reactor and the reaction tank are both made of stainless steel.

9. The carbon dioxide capture and storage device according to claim 8, characterized in that: The alkali solution is a sodium hydroxide solution or a potassium hydroxide solution; The separating agent is calcium oxide.

Images