Efficient electrochemical synthetic ammonia purging and collecting device and electrochemical synthetic ammonia system

Abstract

The invention provides an efficient electrochemical synthetic ammonia purging and collecting device and an electrochemical synthetic ammonia system.The efficient electrochemical synthetic ammonia purging and collecting device comprises an absorption tower, a buffer pool, an electro-catalytic reactor and a purging pipeline, the absorption tower is used for absorbing reaction gas containing nitrogen oxide, and the buffer pool is connected with the absorption tower; the buffer pool is used for storing a high-concentration alkaline solution and receiving an NOx-containing solution from the absorption tower, the buffer pool is provided with a buffer containing cavity, a buffer cavity is formed above the liquid level of the solution in the buffer containing cavity, the electro-catalytic reactor is connected with the buffer pool, and the electro-catalytic reactor is used for performing electro-catalytic reduction on the NOx-containing solution into ammonia gas; the electro-catalytic reactor is provided with a reaction containing cavity, a reaction cavity communicated with the buffer cavity is formed above the liquid level of a solution in the reaction containing cavity, the electro-catalytic reactor is provided with an exhaust port communicated with the reaction cavity and external air, and an air outlet of the purging pipeline is located below the liquid level of the solution in the buffer pool; and the purging pipeline is used for introducing purging gas into the solution in the buffer pool.

Description

Technical Field

[0001] The embodiments of the present invention belong to the field of electrochemical ammonia synthesis technology, specifically relating to a high-efficiency electrochemical ammonia synthesis purging and collection device and an electrochemical ammonia synthesis system. Background Technology

[0002] pNOR-eNO x Electrochemical ammonia synthesis technology has advantages such as mild reaction conditions, low reaction pressure, and high theoretical energy efficiency. This technology comprises two main steps: first, plasma is used to combine nitrogen and oxygen in the air to generate various nitrogen oxides (pNOR); then, an alkaline solution is used to absorb the nitrogen oxides generated in the previous step, converting them into NO. x - Ions (nitrate, nitrite, etc.), which are then reduced to NO via electrocatalytic reduction. x - The ions are reduced to NH3 (eNO3). x Some technical routes combine these two parts into one step, even if the plasma nitrogen oxidation process occurs at the liquid surface of the solution or at the cathode of the electrocatalytic reduction device, to achieve one-step electrochemical synthesis of ammonia.

[0003] The ammonia product synthesized by this method is dispersed in the electrocatalytic reactor and buffer tank solution. Once the solubility limit is reached in the solution, it is released into the cavities of the buffer tank and the reactor. As the ammonia concentration in the gas and liquid phases continuously accumulates, according to Le Chatelier's principle, the high concentration of ammonia drives the reverse reaction (ammonia decomposes into NO). x - This process occurs, leading to a significant decrease in the synthesis conversion rate. Summary of the Invention

[0004] The embodiments of the present invention aim to at least solve one of the technical problems existing in the prior art, and provide a highly efficient electrochemical ammonia synthesis purging and collection device.

[0005] A first aspect of the present invention provides a high-efficiency electrochemical ammonia synthesis purge and collection device, comprising: An absorption tower is used to absorb reaction gases containing nitrogen oxides through a countercurrent alkaline solution. A buffer tank, connected to the absorption tower, is used to store a high-concentration alkaline solution and receive NO-containing solutions from the absorption tower. x - The solution, wherein the buffer pool has a buffer containment cavity for containing the solution, and a buffer cavity is formed above the solution surface in the buffer containment cavity; An electrocatalytic reactor, connected to the buffer tank, is used to react NO with other substances. x- The solution is electrocatalytically reduced to ammonia and an alkaline solution is generated. The electrocatalytic reactor has a reaction chamber for containing the solution. A reaction cavity is formed above the solution surface in the reaction chamber. The buffer cavity is connected to the reaction cavity. The electrocatalytic reactor is provided with an exhaust port, which connects the reaction cavity to the outside air. A purge line, the outlet of which is located below the solution surface in the buffer tank, is used to introduce purge gas into the solution in the buffer tank.

[0006] In some embodiments of the present invention, the outlet of the purging pipeline has multiple pores.

[0007] In some embodiments of the present invention, the purging gas is compressed air.

[0008] In some embodiments of the present invention, the pressure in the reaction cavity is greater than the external atmospheric pressure.

[0009] In some embodiments of the present invention, the pressure difference between the reaction cavity and the external atmospheric pressure ranges from 10 to 100 kPa.

[0010] In some embodiments of the present invention, the exhaust port is provided with a hydrophobic mesh, the hydrophobic mesh having a plurality of mesh openings, and the hydrophobic mesh being made of a hydrophobic material.

[0011] In some embodiments of the present invention, the high-efficiency electrochemical ammonia synthesis purging and collection device includes a gas pipeline that connects the reaction cavity and the buffer cavity, with the two ends of the gas pipeline respectively connected to the top of the electrocatalytic reactor and the top of the buffer tank.

[0012] In some embodiments of the present invention, the alkaline solution in the buffer pool is a KOH solution.

[0013] In some embodiments of the present invention, the apparatus further includes: A first pipeline connects the absorption tower and the buffer tank. One end of the first pipeline is located below the solution surface in the buffer tank, and the other end of the first pipeline is located at the top of the absorption tower. The second pipeline connects the absorption tower and the buffer tank. One end of the second pipeline is connected to the top of the buffer tank, and the other end of the second pipeline is connected to the bottom of the absorption tower.

[0014] A second aspect of the present invention provides an electrochemical ammonia synthesis system, the electrochemical ammonia synthesis system comprising the high-efficiency electrochemical ammonia synthesis purge and collection device according to any of the above embodiments.

[0015] The high-efficiency electrochemical ammonia synthesis purging and collection device and electrochemical ammonia synthesis system of this invention introduce purging gas into the solution of the buffer tank, causing the solution to be agitated by the purging gas to release some ammonia gas. The released ammonia gas is distributed in the buffer cavity and enters the reaction cavity through the buffer cavity, and is finally discharged to the outside through the exhaust port. This reduces the ammonia content in the solution of the buffer tank, avoids the enhancement of the reverse reaction, improves the reaction conversion rate, and ensures the continuous operation of the high-efficiency electrochemical ammonia synthesis purging and collection device and the continuous collection of ammonia products. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of a high-efficiency electrochemical ammonia synthesis purging and collection device.

[0017] The labels in the attached diagram are as follows: 1. Purge pipeline; 2. First pipeline; 3. Second pipeline; 4. Absorption tower; 5. Inlet; 6. Outlet; 7. Buffer tank; 71. Buffer cavity; 8. Third pipeline; 9. Fourth pipeline; 10. Electrocatalytic reactor; 101. Reaction cavity; 11. Exhaust port; 12. Gas pipeline. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the invention. The described embodiments are some, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0019] like Figure 1 As shown, a first aspect of the present invention provides a high-efficiency electrochemical ammonia synthesis purging and collection device, comprising: an absorption tower 4, a buffer tank 7, an electrocatalytic reactor 10, and a purging pipeline 1. The absorption tower 4 is used to absorb nitrogen oxide-containing reaction gases through a countercurrent alkaline solution. The buffer tank 7 is connected to the absorption tower 4 and is used to store high-concentration alkaline solution and receive NO-containing reaction gases from the absorption tower 4. x - The buffer tank 7 has a buffer containment cavity for holding the solution, and a buffer cavity 71 is formed above the solution surface in the buffer containment cavity. The electrocatalytic reactor 10 is connected to the buffer tank 7 and is used to react NO with the solution. x -The solution is electrocatalytically reduced to ammonia and an alkaline solution is generated. The electrocatalytic reactor 10 has a reaction chamber for containing the solution. A reaction cavity 101 is formed above the solution surface in the reaction chamber. A buffer cavity 71 is connected to the reaction cavity 101. An exhaust port 11 is provided on the electrocatalytic reactor 10. The exhaust port 11 connects the reaction cavity 101 with the outside air. The outlet of the purge pipe 1 is located below the solution surface in the buffer tank 7. The purge pipe 1 is used to introduce purge gas into the solution in the buffer tank 7.

[0020] Specifically, the reaction gas containing nitrogen oxides is introduced into the absorption tower 4 through the gas inlet 5. The alkaline solution in the buffer tank 7 enters the absorption tower 4 and reacts with the reaction gas containing nitrogen oxides to absorb the nitrogen oxides and form NO. x - The solution contains NO, and the reacted gas after the nitrogen oxides are absorbed is discharged from the absorption tower 4 through outlet 6. x - The solution was transferred to buffer tank 7, and then NO... x - The solution is fed into the electrocatalytic reactor 10, where the electrocatalytic reactor 10 removes NO. x - The solution is electrocatalytically reduced to ammonia gas and generates an alkaline solution. This alkaline solution is then transported to a buffer tank 7, while the ammonia gas is discharged to the outside through the exhaust port 11 of the electrocatalytic reactor 10. The buffer chamber of the buffer tank 7 contains NO. x - The solution and alkaline solution, the buffer cavity above the solution surface forms a buffer cavity 71, the reaction cavity of the electrocatalytic reactor 10 contains NO x - The buffer tank 7 contains both a solution and an alkaline solution. The reaction chamber above the solution surface forms a reaction cavity 101. The buffer cavity 71 of the buffer tank 7 is connected to the reaction cavity 101 of the electrocatalytic reactor 10, allowing gas flow between the two spaces. Purge gas is introduced into the buffer tank 7 below the solution surface through the purge pipe 1. This agitates the solution in the buffer tank 7 and reduces the ammonia concentration, releasing some of the ammonia from the solution into the buffer cavity 71. The gas then enters the reaction cavity 101 through the buffer cavity 71 and is discharged to the outside through the exhaust port 11 of the reaction cavity 101.

[0021] The high-efficiency electrochemical ammonia synthesis purging and collection device of this invention introduces purging gas into the solution in the buffer tank 7, causing the solution to be agitated by the purging gas to release some ammonia. The released ammonia is distributed in the buffer cavity 71 and enters the reaction cavity 101 through the buffer cavity 71, and is finally discharged to the outside through the exhaust port 11. This reduces the ammonia content in the solution in the buffer tank 7, avoids the enhancement of the reverse reaction, improves the reaction conversion rate, and ensures the continuous operation of the high-efficiency electrochemical ammonia synthesis purging and collection device and the continuous collection of ammonia products.

[0022] In some embodiments of the present invention, the apparatus further includes: a first pipeline 2 and a second pipeline 3. The first pipeline connects the absorption tower 4 and the buffer tank 7, with one end of the first pipeline located below the solution surface in the buffer tank 7 and the other end of the first pipeline located at the top of the absorption tower 4. The second pipeline connects the absorption tower 4 and the buffer tank 7, with one end of the second pipeline connected to the top of the buffer tank 7 and the other end of the second pipeline connected to the bottom of the absorption tower 7. The second pipeline 3 serves to transport the solution after absorbing nitrogen oxides to the buffer tank 7. The second pipeline 3 transports the solution that has absorbed nitrogen oxides in the absorption tower 4 to the buffer tank 7 by gravity, avoiding the impact of the high pressure in the buffer tank 7 caused by the purge gas on the entire circulation pipeline (absorption tower 4 → second pipeline 3 → buffer tank 7 → first pipeline 2 → absorption tower 4).

[0023] In some embodiments of the present invention, the apparatus further includes a third pipe 8 and a fourth pipe 9. The third pipe 8 connects the buffer tank 7 and the electrocatalytic reactor 10, with its two ends connected to the bottom of the buffer tank 7 and the bottom of the electrocatalytic reactor 10, respectively. The fourth pipe 9 connects the buffer tank 7 and the electrocatalytic reactor 10, with its two ends connected to the middle of the buffer tank 7 and the middle of the electrocatalytic reactor 10, respectively. The two ends of the fourth pipe 9 are located below the solution surface in the buffer tank 7 and below the solution surface in the electrocatalytic reactor 10, respectively, so that the fourth pipe 9 is only used for transporting solution and prevents the fourth pipe 9 from connecting the buffer cavity 71 and the reaction cavity 101.

[0024] In some embodiments of the present invention, the outlet of the purge pipe 1 has multiple pores (not shown in the figure), through which the purge air is dispersed into the solution in the buffer tank 7, so that the purge air is more evenly dispersed in the solution, that is, the dispersion area of ​​the purge air in the solution is increased, so that the solution releases more ammonia.

[0025] In some embodiments of the present invention, the purging gas is compressed air. Using compressed air as the purging gas can reduce purging costs, ensure safety, and meet the technical performance requirements of conventional cleaning.

[0026] In some embodiments of the present invention, the pressure in the reaction cavity 101 is greater than the external atmospheric pressure. Specifically, the pressure in the buffer cavity 71 is greater than the pressure in the reaction cavity 101. This greater pressure in the reaction cavity 101 allows ammonia gas released from the solution in the buffer tank 7 to flow from the buffer cavity 71 to the reaction cavity 101, and then from the reaction cavity 101 to the outside. That is, the flow path of ammonia gas in the solution of the buffer tank 7 is: buffer tank 7 solution → buffer cavity 71 → reaction cavity 101 → outside.

[0027] In some embodiments of the present invention, the pressure difference between the reaction cavity 101 and the external atmospheric pressure is in the range of 10~100 kPa, that is, the pressure in the reaction cavity is 10~100 kPa greater than the external atmospheric pressure. When the pressure difference between the reaction cavity 101 and the external atmospheric pressure is within the above range, the ammonia gas in the reaction cavity 101 can flow smoothly to the outside.

[0028] Specifically, by controlling the flow rate of the purge gas introduced into the solution through purge line 1, the pressure of buffer cavity 71 can be controlled, thereby controlling the pressure of reaction cavity 101. Specifically, increasing the flow rate of the purge gas introduced into the solution through purge line 1 through buffer tank 7 increases the pressure of buffer cavity 71, thereby increasing the pressure of reaction cavity 101; decreasing the flow rate of the purge gas introduced into the solution through purge line 1 through buffer tank 7 decreases the pressure of buffer cavity 71, thereby decreasing the pressure of reaction cavity 101.

[0029] In some embodiments of the present invention, the exhaust port 11 is provided with a hydrophobic mesh, which has multiple mesh openings and is made of a hydrophobic material. The hydrophobic mesh, made of a hydrophobic material, can block the passage of solution, thus preserving the solution in the electrocatalytic reactor 10; the multiple mesh openings allow gas to pass through the exhaust port 11, thereby allowing the gas to exit the electrocatalytic reactor 10 through the mesh openings of the exhaust port 11. Specifically, the hydrophobic mesh can be made by coating a hydrophobic coating onto a mesh-like metal or plastic skeleton. The hydrophobic coating can be made of at least one of the following materials: polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), fusible polytetrafluoroethylene (PFA), fluorocarbon wax, polydimethylsiloxane (PDMS), polyolefins (such as polyethylene PE, polypropylene PP), polycarbonate, polyamide, polyester, fluorine-free acrylate, and molten paraffin.

[0030] In some embodiments of the present invention, the high-efficiency electrochemical ammonia synthesis purging and collection device includes a gas pipeline 12, through which the reaction cavity 101 and the buffer cavity 71 are connected. Specifically, the two ends of the gas pipeline 12 are respectively connected to the top of the electrocatalytic reactor 10 and the top of the buffer tank 7, so that the gas pipeline 12 only transports the gas between the reaction cavity 101 and the buffer cavity 71, preventing liquid from flowing through the gas pipeline 12.

[0031] In some embodiments of the present invention, the alkaline solution in buffer tank 7 is a KOH solution. Among common alkaline electrolytes, potassium hydroxide (KOH) has better conductivity than sodium hydroxide (NaOH), resulting in lower solution resistance, which helps save energy during electrolysis and improves the energy efficiency of the entire electrochemical ammonia synthesis system.

[0032] A second aspect of the present invention provides an electrochemical ammonia synthesis system, the electrochemical ammonia synthesis system comprising the high-efficiency electrochemical ammonia synthesis purge and collection device according to any of the above embodiments.

[0033] The electrochemical ammonia synthesis system of this invention introduces purge gas into the solution in buffer tank 7, causing the solution to be agitated by the purge gas to release some ammonia. The released ammonia is distributed in buffer cavity 71 and enters reaction cavity 101 through buffer cavity 71, and is finally discharged to the outside through exhaust port 11. This reduces the ammonia content in the solution in buffer tank 7, avoids the enhancement of reverse reaction, improves reaction conversion rate, ensures the continuous operation of the high-efficiency electrochemical ammonia synthesis purge collection device, ensures the continuous operation of the electrochemical ammonia synthesis system, and ensures the continuous collection of ammonia products.

[0034] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A high-efficiency electrochemical ammonia synthesis purging and collection device, characterized in that, include: An absorption tower is used to absorb reaction gases containing nitrogen oxides through a countercurrent alkaline solution. A buffer tank, connected to the absorption tower, is used to store a high-concentration alkaline solution and receive NO-containing solutions from the absorption tower. x - The solution, wherein the buffer pool has a buffer containment cavity for containing the solution, and a buffer cavity is formed above the solution surface in the buffer containment cavity; An electrocatalytic reactor, connected to the buffer tank, is used to react NO with other substances. x - The solution is electrocatalytically reduced to ammonia and an alkaline solution is generated. The electrocatalytic reactor has a reaction chamber for containing the solution. A reaction cavity is formed above the solution surface in the reaction chamber. The buffer cavity is connected to the reaction cavity. The electrocatalytic reactor is provided with an exhaust port, which connects the reaction cavity to the outside air. A purge line, the outlet of which is located below the solution surface in the buffer tank, is used to introduce purge gas into the solution in the buffer tank.

2. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The outlet of the purging pipeline has multiple pores.

3. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The purging gas is compressed air.

4. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The pressure in the reaction cavity is greater than the external atmospheric pressure.

5. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 4, characterized in that, The pressure difference between the reaction cavity and the external atmospheric pressure ranges from 10 to 100 kPa.

6. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The exhaust port is equipped with a hydrophobic mesh, which has multiple mesh openings and is made of a hydrophobic material.

7. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The high-efficiency electrochemical ammonia synthesis purging and collection device includes a gas pipeline that connects the reaction cavity and the buffer cavity, with the two ends of the gas pipeline connected to the top of the electrocatalytic reactor and the top of the buffer tank, respectively.

8. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The alkaline solution in the buffer tank is a KOH solution.

9. The high-efficiency electrochemical ammonia synthesis purging and collection device according to claim 1, characterized in that, The device further includes: A first pipeline connects the absorption tower and the buffer tank. One end of the first pipeline is located below the solution surface in the buffer tank, and the other end of the first pipeline is located at the top of the absorption tower. The second pipeline connects the absorption tower and the buffer tank. One end of the second pipeline is connected to the top of the buffer tank, and the other end of the second pipeline is connected to the bottom of the absorption tower.

10. An electrochemical ammonia synthesis system, characterized in that, The electrochemical ammonia synthesis system includes a high-efficiency electrochemical ammonia synthesis purging and collection device according to any one of claims 1 to 9.

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