A method for removing NOx from carbon dioxide gas source

Abstract

The invention discloses a method for finely removing NOx from a carbon dioxide gas source, belonging to the technical field of carbon dioxide purification. The method utilizes ammonia, O2 in the carbon dioxide gas source, water vapor, and NOx to undergo an oxidation reaction to generate nitrates and / or nitrites, and the ammonia salts are adsorbed on a moist interface to remove NOx from the carbon dioxide gas source. Specifically, the method changes the reaction chamber into which the carbon dioxide gas source and ammonia gas are input, coordinately changes the oxidation reaction and reduction reaction in a first reaction chamber and a second reaction chamber, and utilizes a first channel to transmit gas after partial NOx removal and a second channel to transmit ammonia to form a gas loop between the first reaction chamber and the second reaction chamber, so that the NOx removal from the carbon dioxide gas source and the reduction reaction to generate ammonia are alternately circulated in the first reaction chamber and the second reaction chamber, respectively, thereby achieving continuous deNOx treatment of the carbon dioxide gas source, so that the residual NOx in the output gas can meet the standard of food-grade carbon dioxide.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide purification, and in particular relates to a method for finely removing NOx from a carbon dioxide gas source. Background Art

[0002] Carbon dioxide is a valuable resource widely used in a variety of fields, including chemical synthesis, mechanical shielded welding, metal casting, agricultural fertilization, fruit and vegetable preservation, beer and beverage bottling, oil extraction, firefighting, and medicine and health. However, due to inadequate carbon dioxide recovery measures, less than 1% of carbon dioxide emissions are recycled and reused annually, contributing to atmospheric pollution, the terrifying greenhouse effect, and a waste of precious resources.

[0003] Existing carbon dioxide purification usually uses adsorption materials such as activated carbon. Due to the lack of good adsorption materials specifically for NO x The selective adsorption material has poor targeting and cannot guarantee the NO in CO2 gas after adsorption. x The balance can reach the standard of food grade carbon dioxide. In addition, the low temperature distillation process is used to remove NO from CO2. x , but the distillation tower is expensive and has poor economic efficiency. Summary of the Invention

[0004] In response to one or more of the above-mentioned defects or improvement needs in the prior art, the present invention provides a method for fine deNOx treatment of a carbon dioxide gas source, which can achieve continuous deNOx treatment of a carbon dioxide gas source containing CO2, NOx, N2, O2, and water vapor, so that the residual NOx in the output gas can meet the standard of food-grade carbon dioxide, with high efficiency and good economy.

[0005] To achieve the above object, the present invention provides a method for removing NOx from a carbon dioxide gas source for preparing food-grade carbon dioxide, wherein the carbon dioxide gas source contains CO2, NOx, N2, O2, and water vapor, and comprises the following steps:

[0006] S1: A carbon dioxide gas source and excess ammonia gas are introduced into a first reaction chamber to form a wet interface in the first reaction chamber; NOx undergoes an oxidation reaction in the first reaction chamber and is converted into nitrate and / or nitrite adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source; the gas from the first reaction chamber after the NOx is removed is introduced into a second reaction chamber;

[0007] S2: A carbon dioxide gas source is introduced into the second reaction chamber and a wet interface is formed in the second reaction chamber; NOx undergoes an oxidation reaction in the second reaction chamber and is converted into nitrate and / or nitrite adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source; the gas from the second reaction chamber after the NOx is removed is partially introduced into the first reaction chamber along the first channel, and partially discharged; simultaneously, the nitrate and nitrite in the first reaction chamber undergo a reduction reaction to generate ammonia, and the ammonia in the first reaction chamber is introduced into the second reaction chamber along the second channel to participate in the process of converting NOx into nitrate and / or nitrite;

[0008] S3: A carbon dioxide gas source is introduced into the first reaction chamber and a wet interface is formed in the first reaction chamber; NOx undergoes an oxidation reaction in the first reaction chamber and is converted into nitrate and / or nitrite adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source; a portion of the gas from the first reaction chamber after the NOx is removed is introduced into the second reaction chamber along the first channel, and a portion is discharged; simultaneously, the nitrate and nitrite in the second reaction chamber undergo a reduction reaction to generate ammonia, and the ammonia in the second reaction chamber is introduced into the first reaction chamber along the second channel to participate in the process of converting NOx into nitrate and / or nitrite;

[0009] S4: Repeat steps S2 to S3 until all the carbon dioxide gas sources have been completely deNOxed.

[0010] As a further improvement of the present invention, the method for precise deNOxification of a carbon dioxide gas source further comprises: testing the NOx content of the discharged gas after deNOxification to determine whether the gas meets the standard of food-grade carbon dioxide.

[0011] As a further improvement of the present invention, the method for fine NOx removal from a carbon dioxide gas source further comprises: passing the discharged gas after NOx removal into a water washing and dehydration device for deammoniation treatment.

[0012] As a further improvement of the present invention, steps S1, S2, and S3 may be respectively performed for a predetermined time.

[0013] As a further improvement of the present invention, the oxidation reaction and the reduction reaction are carried out in the following manner:

[0014] A plurality of first anode plates and a plurality of first cathode plates are arranged alternately in parallel in the first reaction chamber, and a plurality of second anode plates and a plurality of second cathode plates are arranged alternately in parallel in the second reaction chamber. The positive pole of the power supply is connected to the first anode plate / the second anode plate for oxidation reaction, and the negative pole of the power supply is connected to the first cathode plate / the second cathode plate for reduction reaction.

[0015] As a further improvement of the present invention, the method for precise NOx removal from a carbon dioxide gas source further comprises: before the carbon dioxide gas source is introduced into the first reaction chamber / the second reaction chamber, electrons are input into the carbon dioxide gas source.

[0016] As a further improvement of the present invention, the moist interface is formed by filling a conductive catalyst adsorbent between adjacent first anode plates and first cathode plates, and filling a conductive catalyst adsorbent between adjacent second anode plates and second cathode plates, wherein the conductive catalyst adsorbent absorbs water vapor in the carbon dioxide gas source to form a moist interface.

[0017] As a further improvement of the present invention, the conductive catalyst adsorbent is composed of basic magnesium carbonate, catalyst components and metal foam, wherein basic magnesium carbonate is a carrier for absorbing NOx, the catalyst components are composed of Fe2TiO5, Zn, and ZnO, and the metal foam is a conductive substrate.

[0018] As a further improvement of the present invention, the method for removing NOx from a carbon dioxide gas source further includes: before the carbon dioxide gas source is introduced into the first reaction chamber / the second reaction chamber, detecting the water vapor content of the carbon dioxide gas source; if the water vapor content is insufficient, inputting a certain amount of water vapor into the carbon dioxide gas source.

[0019] As a further improvement of the present invention, a conductive catalyst adsorbent is also filled between the outermost first anode plate / first cathode plate and the first reaction chamber;

[0020] and / or,

[0021] The space between the outermost second anode plate / second cathode plate and the second reaction chamber is also filled with a conductive catalyst adsorbent.

[0022] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0023] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0024] (1) The method for removing NOx from a carbon dioxide gas source of the present invention utilizes ammonia, O2 in the carbon dioxide gas source, water vapor, and NOx to undergo an oxidation reaction to generate nitrates and / or nitrites, and ammonia salts are adsorbed on a moist interface to remove NOx from the carbon dioxide gas source; specifically, by changing the reaction chamber of the carbon dioxide gas source, coordinating the changes in the oxidation reaction and the reduction reaction in the first reaction chamber and the second reaction chamber, and utilizing the first channel to transmit the gas after partial removal of NOx and the second channel to transmit ammonia to form a gas loop between the first reaction chamber and the second reaction chamber, so that the NOx removal from the carbon dioxide gas source and the reduction reaction to generate ammonia are alternately circulated in the first reaction chamber and the second reaction chamber, respectively, thereby achieving continuous deNOx treatment of the carbon dioxide gas source, so that the residual NOx in the output gas can meet the standard of food-grade carbon dioxide, with high NOx removal efficiency and better economy.

[0025] (2) The method for removing NOx from a carbon dioxide gas source of the present invention improves the activity and conductivity of the carbon dioxide gas source by inputting electrons into the carbon dioxide gas source before it is introduced into the first reaction chamber / the second reaction chamber, and can also stimulate the activity of the catalyst. In addition, the collision and absorption of the electrons with the electrodes, catalysts and other metal materials in the first reaction chamber / the second reaction chamber can also heat the metal materials, increase the temperature in the tower, accelerate the reaction rate, and improve the efficiency of removing NOx.

[0026] (3) The method for removing NOx from a carbon dioxide gas source of the present invention compensates for the insufficient water content of the carbon dioxide gas source by inputting water vapor into the carbon dioxide gas source before it is introduced into the first reaction chamber / the second reaction chamber. An appropriate amount of water vapor content can not only increase the conductivity of the carbon dioxide gas source, but also help create a moist interface required for the electrochemical reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 1 is a flow chart of a method for removing NOx from a carbon dioxide gas source according to an embodiment of the present invention.

[0029] Figure 2 Schematic diagram of a CO2 purification system based on electrocatalytic oxidation-reduction adsorption and precise NOx removal in an embodiment of the present invention.

[0030] In all the drawings, the same reference numerals represent the same technical features, specifically: 1. first tower body; 101. first anode plate; 102. first cathode plate; 2. second tower body; 201. second anode plate; 202. second cathode plate; 3. electrocatalytic power supply; 4. feed pipe; 5. discharge pipe; 6. feed pipe; 601. first feed pipe; 6011. first valve; 602. second feed pipe; 6021. second valve; 7. feed pipe; 701. first feed pipe; Material pipeline; 7011, third valve; 702, second material supply pipeline; 7021, fourth valve; 8, return pipe; 801, fifth valve; 802, sixth valve; 9, siphon type three-way connector; 901, first inlet; 902, second inlet; 903, outlet; 10, electron beam generator; 11, water vapor supply pipe; 12, first analysis indicator; 13, second analysis indicator; 14, pressure indicator; 15, temperature indicator; 16, differential pressure detection meter. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0033] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0034] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0036] Example

[0037] Please refer to Figure 1 The method for removing NOx from a carbon dioxide gas source in a preferred embodiment of the present invention is used to prepare food-grade carbon dioxide, wherein the carbon dioxide gas source contains CO2, NOx, N2, O2, and water vapor, and comprises the following steps:

[0038] S1: A carbon dioxide gas source and excess ammonia gas are introduced into a first reaction chamber to form a wet interface in the first reaction chamber; NOx undergoes an oxidation reaction in the first reaction chamber and is converted into nitrate and / or nitrite adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source; the gas from the first reaction chamber after the NOx is removed is introduced into a second reaction chamber;

[0039] S2: A carbon dioxide gas source is introduced into the second reaction chamber and a wet interface is formed in the second reaction chamber; NOx undergoes an oxidation reaction in the second reaction chamber and is converted into nitrate and / or nitrite adsorbed on the wet interface, completing the removal of NOx from the carbon dioxide gas source, and a portion of the refined de-reaction gas in the second reaction chamber is introduced into the first reaction chamber along the first channel, and a portion is discharged; simultaneously, the nitrate and nitrite in the first reaction chamber undergo a reduction reaction to generate ammonia, and the ammonia in the first reaction chamber is introduced into the second reaction chamber along the second channel to participate in the process of converting NOx into nitrate and / or nitrite;

[0040] S3: A carbon dioxide gas source is introduced into the first reaction chamber and a wet interface is formed in the first reaction chamber; NOx undergoes an oxidation reaction in the first reaction chamber and is converted into nitrate and / or nitrite adsorbed on the wet interface, completing the removal of NOx from the carbon dioxide gas source, and a portion of the refined de-reaction gas in the first reaction chamber is introduced into the second reaction chamber along the first channel, and a portion is discharged; simultaneously, the nitrate and nitrite in the second reaction chamber undergo a reduction reaction to generate ammonia, and the ammonia in the second reaction chamber is introduced into the first reaction chamber along the second channel to participate in the process of converting NOx into nitrate and / or nitrite;

[0041] S4: Repeat steps S2 to S3 until all the carbon dioxide gas sources have been completely deNOxed.

[0042] Wherein, NOx includes NO and NO2. NO undergoes an oxidation reaction to form nitrite, and NO2 undergoes an oxidation reaction to form nitrate. Since an excess of ammonia is input into the first reaction chamber in step S1, the gas after NOx removal in the first reaction chamber in step S1 also contains ammonia. In steps S2 and S3, when NOx is converted into nitrate and / or nitrite in one reaction chamber, a portion of the ammonia is consumed, while the other reaction chamber generates and replenishes ammonia. Therefore, in steps S2 and S3, the gas after NOx removal in the first reaction chamber / the second reaction chamber also contains ammonia.

[0043] The method for precise deNOx removal from a carbon dioxide gas source of the present invention utilizes ammonia, O2 in the carbon dioxide gas source, water vapor, and NOx to undergo an oxidation reaction to generate nitrates and / or nitrites, which are then adsorbed on a moist interface to remove NOx from the carbon dioxide gas source. Furthermore, ammonia generated by the nitrates and / or nitrites and the ammonia salts during the reduction reaction can also rapidly enter and exit the moist interface phase. By changing the reaction chambers into which the carbon dioxide gas source and ammonia gas are input, coordinating the oxidation reaction and the reduction reaction in the first reaction chamber and the second reaction chamber, and utilizing the first channel to transmit partially deNOxed gas and the second channel to transmit ammonia to form a gas loop between the first reaction chamber and the second reaction chamber, the deNOx removal from the carbon dioxide gas source and the reduction reaction to generate ammonia are alternately performed in the first reaction chamber and the second reaction chamber, respectively. This allows continuous deNOx treatment of the carbon dioxide gas source to be achieved, resulting in high NOx removal efficiency and good economic efficiency.

[0044] Preferably, steps S1, S2, and S3 can each be performed for a predetermined time period. The predetermined time period can be comprehensively calculated based on the NOx content in the introduced carbon dioxide source, the catalyst content in the first reaction chamber / the second reaction chamber, the reducing gas content, and the electrochemical reaction rate, so that the NOx in the carbon dioxide source can be fully adsorbed and removed within the predetermined time period. In a specific embodiment, the predetermined time period can be 30 seconds to 60 seconds, 1 minute, 2 minutes, etc.

[0045] Since the discharged gas after deNOx carries some ammonia, the method for fine deNOx of carbon dioxide gas source of the present invention preferably further comprises: passing the discharged gas after deNOx into a water washing and dehydration device for deammoniation treatment.

[0046] Preferably, the method for precise deNOxification of a carbon dioxide gas source of the present invention further comprises: testing the NOx content of the discharged gas after deNOxification to determine whether it meets the standard of food-grade carbon dioxide.

[0047] Further preferably, the oxidation reaction and the reduction reaction are carried out in the following manner:

[0048] A plurality of first anode plates and a plurality of first cathode plates are arranged alternately in parallel in the first reaction chamber, and a plurality of second anode plates and a plurality of second cathode plates are arranged alternately in parallel in the second reaction chamber. The positive pole of the power supply is connected to the first anode plate / the second anode plate for oxidation reaction, and the negative pole of the power supply is connected to the first cathode plate / the second cathode plate for reduction reaction.

[0049] Preferably, the moist interface is formed by filling a conductive catalyst adsorbent between adjacent first anode plates and first cathode plates, and filling a conductive catalyst adsorbent between adjacent second anode plates and second cathode plates, wherein the conductive catalyst adsorbent absorbs water vapor in the carbon dioxide gas source to form a moist interface.

[0050] Further preferably, a conductive catalyst adsorbent is also filled between the outermost first anode plate / first cathode plate and the first reaction chamber; and a conductive catalyst adsorbent is also filled between the outermost second anode plate / second cathode plate and the second reaction chamber.

[0051] Furthermore, the method for fine NOx removal from a carbon dioxide gas source of the present invention also includes: before the carbon dioxide gas source is introduced into the first reaction chamber / the second reaction chamber, electrons are input into the carbon dioxide gas source, which can, on the one hand, improve the activity and conductivity of the carbon dioxide gas source, and on the other hand, stimulate the activity of the catalyst. In addition, the collision and absorption of the electrons with metal materials such as electrodes and catalysts in the first reaction chamber / the second reaction chamber can also heat the metal materials, increase the temperature in the tower, and accelerate the reaction speed.

[0052] When the water vapor content in the carbon dioxide gas source is low, water vapor needs to be added to the carbon dioxide gas source to increase the conductivity of the gas. An appropriate amount of water vapor content can not only increase the conductivity of the carbon dioxide gas source, but also help create the moist interface required for the electrochemical reaction.

[0053] Preferably, the method for removing NOx from a carbon dioxide gas source of the present invention further comprises: detecting the water vapor content of the carbon dioxide gas source before the carbon dioxide gas source is introduced into the first reaction chamber / the second reaction chamber; if the water vapor content is insufficient, inputting a certain amount of water vapor into the carbon dioxide gas source.

[0054] Preferably, the conductive catalyst adsorbent is composed of basic magnesium carbonate, a catalyst component and metal foam, wherein the basic magnesium carbonate is a carrier for absorbing NOx, the catalyst component is composed of Fe2TiO5, Zn, and ZnO, and the metal foam is a conductive substrate.

[0055] In this embodiment, basic magnesium carbonate initially absorbs CO2 in the carbon dioxide gas source to form bicarbonate until no more absorption occurs. The bicarbonate reacts with water vapor to ionize and becomes weakly alkaline. The Fe2TiO5, Zn, and ZnO components in the catalyst are preferably 1:1:1. The metal foam is preferably titanium metal foam.

[0056] The following specific preferred embodiment is an electrocatalytic oxidation-reduction adsorption NOx removal system for CO2 purification to implement the present method.

[0057] See also Figure 2 The CO2 purification system based on electrocatalytic redox adsorption for fine NOx removal in the preferred embodiment includes a first tower body 1, a second tower body 2, an electrocatalytic power supply 3, a feed pipe 4, a discharge pipe 5, a feed pipe 6, a supply pipe 7, a return pipe 8 and a siphon-type three-way joint 9, wherein the first tower body 1 and the second tower body 2 correspond to the first reaction chamber and the second reaction chamber in the present method, respectively.

[0058] Specifically, the siphon-type three-way joint 9 includes a first inlet 901, a second inlet 902 and an outlet 903, and a Venturi tube structure is provided between the first inlet 901 and the outlet 903 of the siphon-type three-way joint 9; the first inlet 901 is connected to the feed pipe 4, which is used to input a carbon dioxide gas source; the outlet 903 is connected to the feeding pipe 6, and the feeding pipe 6 includes a first feeding pipe 601 and a second feeding pipe 602 that can be controlled to open and close, and are used to provide a carbon dioxide gas source to the first tower body 1 and the second tower body 2 respectively; the second inlet 902 is connected to the feeding pipe 7, and the feeding pipe 7 includes a first feeding pipe 701 and a second feeding pipe 702 that can be controlled to open and close, and are used to provide a reducing gas to the first tower body 1 and the second tower body 2 respectively; the return pipe 8 connects the top of the first tower body 1 with the top of the second tower body 2, and the return pipe 8 is also connected to a discharge pipe 5 for transporting the output gas after deNOx.

[0059] In this embodiment, the venturi tube structure adopted by the siphon type three-way joint 9 allows gas to enter from the first inlet 901 and the second inlet 902 and be output from the outlet 903, thereby ensuring the direction of gas transmission.

[0060] Preferably, the first feeding pipeline 601 , the second feeding pipeline 602 , the first supply pipeline 701 , and the second supply pipeline 702 are respectively opened and closed by the first valve 6011 , the second valve 6021 , the third valve 7011 , and the fourth valve 7021 .

[0061] Furthermore, a plurality of first anode plates 101 and a plurality of first cathode plates 102 are arranged alternately in parallel in the first tower body 1, and a conductive catalyst adsorbent is filled between adjacent first anode plates 101 and first cathode plates 102; a plurality of second anode plates 201 and a plurality of second cathode plates 202 are arranged alternately in parallel in the second tower body 2, and a conductive catalyst adsorbent is filled between adjacent second anode plates 201 and second cathode plates 202. The conductive catalyst adsorbent can absorb water vapor in the carbon dioxide gas source to form a humid interface; the electrocatalytic power source 3 can be respectively connected to the first anode plate 101 and the first cathode plate 102. The electrode plate 101, the first cathode plate 102, the second anode plate 201, and the second cathode plate 202 are electrically connected to provide electrical energy for the electrochemical reaction in the first tower body 1 and the second tower body 2, so that the oxidation reaction of the anode plate and the reduction reaction of the cathode plate can be carried out alternately in the first tower body 1 and the second tower body 2, respectively. The reduction reaction is used to generate reducing gas, and the oxidation reaction converts NOx in the carbon dioxide gas source and the reducing gas into nitrate and / or nitrite at the wet interface. The nitrate and nitrite are ionized to form nitrate and nitrite, which are adsorbed on the wet interface to complete the removal of NOx.

[0062] Preferably, before the first operation of the system, reducing gas needs to be introduced into both the first tower body 1 and the second tower body 2 .

[0063] For example, the specific operation process of the system for removing NOx from the carbon dioxide gas source is as follows: open the first valve 6011 and the fourth valve 7021, close the second valve 6021 and the third valve 7011, and connect the positive electrode and the negative electrode of the electrocatalytic power supply 3 to the first anode plate 101 and the second cathode plate 202 respectively. The carbon dioxide gas source is input from the inlet of the feed pipe 4 and enters the first tower body 1 through the siphon tee joint 9 and the first feeding pipe 601. The reducing gas in the second tower body 2 can also enter the first tower body 1 through the second feeding pipe 702, the siphon tee joint 9, and the first feeding pipe 601. The conductive catalyst adsorbent in the first tower body 1 absorbs the carbon dioxide gas source. The water vapor forms a wet interface, NOx, water vapor, and O2 in the carbon dioxide gas source undergo an oxidation reaction to produce nitric acid and / or nitrous acid, which further react with the reducing gas to produce nitrate and / or nitrite, which ionizes to form nitrate and nitrite, which are adsorbed on the wet interface to complete the removal of NOx. At this time, the gas after NOx removal in the first tower body 1 also contains reducing gas, part of which is discharged along the discharge pipe 5, and the other part enters the second tower body 2 from the return pipe 8 to continue to push the reducing gas in the second tower body 2 to be input into the first tower body 1 for replenishment, so that the carbon dioxide gas source that continues to enter the first tower body 1 continues to complete the removal of NOx;

[0064] Furthermore, the first valve 6011 and the fourth valve 7021 are closed, the second valve 6021 and the third valve 7011 are opened, and the positive electrode and the negative electrode of the electrocatalytic power supply 3 are connected to the second anode plate 201 and the first cathode plate 102 respectively. The carbon dioxide gas source is input from the inlet of the feed pipe 4 and enters the second tower body 2 through the siphon tee joint 9 and the second feeding pipe 602. At this time, the nitrate and nitrite in the first tower body 1 undergo a reduction reaction to produce a reducing gas, which also enters the second tower body 2 through the first feeding pipe 701, the siphon tee joint 9, and the second feeding pipe 602; the conductive catalyst adsorbent in the second tower body 2 absorbs water in the carbon dioxide gas source. The steam forms a wet interface, and the NOx, water vapor, and O2 in the carbon dioxide gas source undergo an oxidation reaction to produce nitric acid or nitrous acid. The nitric acid or nitrous acid further reacts with the reducing gas to produce nitrate and / or nitrite. The nitrate and / or nitrite are ionized to form nitrate and / or nitrite, which are adsorbed on the wet interface to complete the removal of NOx. At this time, the gas after the NOx is removed in the second tower body 2 also contains reducing gas, a part of which is discharged along the discharge pipe 5, and the other part enters the first tower body 1 from the return pipe 8 to continue to push the reducing gas in the first tower body 1 to be input into the second tower body 2 for replenishment, so that the carbon dioxide gas source that continues to enter the second tower body 2 continues to complete the removal of NOx;

[0065] By continuing to change the connection mode of the electrocatalytic power supply 3 and the opening and closing conditions of the first valve 6011, the fourth valve 7021, the second valve 6021, and the third valve 7011, the oxidation reaction and the reduction reaction continue to cycle alternately in the first tower body 1 and the second tower body 2, thereby achieving continuous deNOx treatment of the carbon dioxide gas source.

[0066] This system directs the flow of the carbon dioxide source gas and reducing gas through channel control via feed pipes 6 and 7. The electrocatalytic power source 3 controls the electrochemical reaction within the first and second tower bodies 1 and 2. The partially deNOxed gas and reducing gas form a gas flow loop between the first and second tower bodies 1 and 2, allowing the NOx adsorption reaction of the carbon dioxide source gas to alternately cycle on the conductive catalyst adsorbents in the first and second tower bodies 1 and 2. This achieves continuous deNOx treatment of the carbon dioxide source gas, ensuring that the residual NOx in the output gas meets food-grade standards. This system is highly efficient and economical for precise deNOx removal from carbon dioxide sources.

[0067] Preferably, a conductive catalyst adsorbent is also filled between the outermost first anode plate 101 / first cathode plate 102 and the first tower body 1 ; a conductive catalyst adsorbent is also filled between the outermost second anode plate 201 / second cathode plate 202 and the second tower body 2 .

[0068] Preferably, an electron beam generator 10 is provided on the feed pipe 4 for outputting electrons into the carbon dioxide gas source to improve the activity and conductivity of the carbon dioxide gas source, and at the same time stimulate the activity of the catalyst. In addition, the collision and absorption of the electrons with the electrodes, catalysts and other metal materials in the first tower body 1 / second tower body 2 can also heat the metal materials, increase the temperature in the tower, and accelerate the reaction speed.

[0069] Preferably, the conductive catalyst adsorbent is composed of basic magnesium carbonate, a catalyst and metal foam, wherein the basic magnesium carbonate is a carrier for absorbing NOx, the catalyst is composed of Fe2TiO5, Zn, and ZnO, and the metal foam is a conductive substrate.

[0070] In this embodiment, basic magnesium carbonate initially absorbs CO2 in the carbon dioxide gas source to form bicarbonate until no more absorption occurs. The bicarbonate reacts with water vapor to ionize and becomes weakly alkaline. The Fe2TiO5, Zn, and ZnO components in the catalyst are preferably 1:1:1. The metal foam is preferably titanium metal foam.

[0071] In a preferred embodiment, a water vapor supply pipe 11 is connected to the feed pipe 4 for supplying water vapor to the carbon dioxide source. When the water vapor content of the carbon dioxide source is low, the water vapor supply pipe 11 can add water vapor to the carbon dioxide source. An appropriate amount of water vapor not only increases the conductivity of the carbon dioxide source but also helps create the moist interface required for the electrochemical reaction.

[0072] Specifically preferably, a first analysis indicator 12 is provided on the feed pipe 4 for monitoring the content of NOx and water vapor in the carbon dioxide gas source to determine whether the water vapor content is insufficient. The first analysis indicator 12 is located between the connection of the water vapor supply pipe 11 and the siphon tee joint 9.

[0073] Preferably, a second analytical indicator 13 is provided on the discharge pipe 5 to monitor the NOx and water vapor content in the output gas, thereby ensuring that the residual NOx in the output gas meets food-grade carbon dioxide standards. Furthermore, when the second analytical indicator 13 detects that the residual NOx in the output gas reaches a certain value, the oxidation reaction and the reduction reaction in the first tower body 1 and the second tower body 2 can be switched to avoid insufficient residual reducing gas.

[0074] Preferably, the feed pipe 4 is further provided with a pressure indicator 14 and a temperature indicator 15 for monitoring the pressure and temperature of the carbon dioxide gas source, respectively.

[0075] Preferably, the first tower body 1 and the second tower body 2 are both provided with a pressure difference detection meter 16 for monitoring the pressure difference between the bottom and the top of the first tower body 1 and the second tower body 2 to avoid excessive pressure difference in the first tower body 1 and the second tower body 2.

[0076] In a preferred embodiment, the oxidation reaction and the reduction reaction in the first tower body 1 and the second tower body 2 are alternated at predetermined intervals. The predetermined time can be comprehensively calculated based on the NOx content in the introduced carbon dioxide gas source, the content of the catalyst in the first tower body 1 / the second tower body 2, the content of the reducing gas, and the electrochemical reaction rate, so that the NOx in the carbon dioxide gas source can be fully adsorbed and removed within the predetermined time period.

[0077] Exemplarily, the predetermined time may be 30s to 60s.

[0078] Preferably, the reducing gas is ammonia, which can react with nitric acid and nitrous acid to produce nitrates and / or nitrites and ammonia salts, and the ammonia produced by the nitrates and / or nitrites and ammonia salts during the reduction reaction can also quickly enter and exit the wet interface phase.

[0079] Furthermore, when the reducing gas is ammonia, a portion of the ammonium salt ions dispersed in the gas phase will be carried out of the first tower body 1 / second tower body 2 along with the output gas. The discharge pipe 5 is preferably connected to a water washing device and a dehydration device to complete the deammoniation of the output gas.

[0080] Preferably, the first anode plate 101 and the second anode plate 201 are made of titanium alloy, and the first cathode plate 102 and the second cathode plate 202 are made of magnesium-aluminum alloy.

[0081] Preferably, a fifth valve 801 and a sixth valve 802 are provided on the return pipe 8, and the fifth valve 801 and the sixth valve 802 are respectively located on both sides of the discharge pipe 5 to distribute the ratio of the output gas after deNOx entering the discharge pipe 5 and the other tower body.

[0082] It should be noted that the temperature within the first and second tower bodies 1, 2 of this system does not exceed 50 degrees Celsius to prevent ammonia from reacting with oxygen. Furthermore, as the catalytic redox reaction proceeds, the Zn in the catalyst and the magnesium-aluminum alloy on the cathode plate are gradually consumed. Basic magnesium carbonate is also slowly consumed, producing substances such as magnesium nitrate and zinc nitrate. Therefore, the conductive catalyst adsorbent and negative plate need to be replaced promptly.

[0083] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for removing NOx from a carbon dioxide gas source for preparing food-grade carbon dioxide, wherein the carbon dioxide gas source contains CO2, NOx, N2, O2, and water vapor, characterized in that: The steps include: S1: A carbon dioxide gas source and excess ammonia are introduced into a first reaction chamber to form a wet interface in the first reaction chamber; NOx, water vapor, and O2 in the carbon dioxide gas source undergo an oxidation reaction in the first reaction chamber to produce nitric acid and / or nitrous acid, which further react with ammonia to produce nitrates and / or nitrites. The nitrates and / or nitrites are ionized to form nitrates and nitrites that are adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source; the gas from the first reaction chamber after the NOx removal is introduced into a second reaction chamber; S2: A carbon dioxide gas source is input into a second reaction chamber and a wet interface is formed in the second reaction chamber; NOx, water vapor, and O2 in the carbon dioxide gas source undergo an oxidation reaction in the second reaction chamber to produce nitric acid and / or nitrous acid, which further react with ammonia to produce nitrate and / or nitrite, which are ionized to form nitrate and nitrite, which are adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source, and partially inputting the gas from the second reaction chamber after the NOx is removed into the first reaction chamber along the first channel, and partially discharging the gas; simultaneously, the nitrate and nitrite in the first reaction chamber undergo a reduction reaction to generate ammonia, and the ammonia in the first reaction chamber is input into the second reaction chamber along the second channel to participate in the process of converting NOx into nitrate and / or nitrite; S3: A carbon dioxide gas source is input into a first reaction chamber and a wet interface is formed in the first reaction chamber; NOx, water vapor, and O2 in the carbon dioxide gas source undergo an oxidation reaction in the first reaction chamber to produce nitric acid and / or nitrous acid, which further react with ammonia to produce nitrate and / or nitrite, which are ionized to form nitrate and nitrite, which are adsorbed on the wet interface, thereby completing the removal of NOx from the carbon dioxide gas source, and partially inputting the gas from the first reaction chamber after the NOx is removed along the first channel into the second reaction chamber, and partially discharging the gas; simultaneously, the nitrate and nitrite in the second reaction chamber undergo a reduction reaction to generate ammonia, and the ammonia in the second reaction chamber is input into the first reaction chamber along the second channel to participate in the process of converting NOx into nitrate and / or nitrite; S4: Repeat steps S2 to S3 until all carbon dioxide gas sources have completed the fine removal of NOx; The oxidation reaction and the reduction reaction are carried out in the following manner: A plurality of first anode plates and a plurality of first cathode plates are arranged alternately in parallel in a first reaction chamber, and a plurality of second anode plates and a plurality of second cathode plates are arranged alternately in parallel in a second reaction chamber. A conductive catalyst adsorbent is filled between adjacent first anode plates and first cathode plates, and a conductive catalyst adsorbent is filled between adjacent second anode plates and second cathode plates. The conductive catalyst adsorbent absorbs water vapor in a carbon dioxide gas source to form a moist interface. The positive pole of the power supply is connected to the first anode plate / second anode plate for an oxidation reaction, and the negative pole of the power supply is connected to the first cathode plate / second cathode plate for a reduction reaction.

2. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: Also includes: The NOx content of the discharged gas after NOx removal is tested to determine whether it meets the standards of food-grade carbon dioxide.

3. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: Also includes: The discharged gas after NOx removal is passed into the water washing and dehydration device for deammonification treatment.

4. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: Steps S1, S2, and S3 may each continue for a predetermined time.

5. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: Also includes: Before the carbon dioxide gas source is introduced into the first reaction chamber / the second reaction chamber, electrons are input into the carbon dioxide gas source.

6. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: The conductive catalyst adsorbent consists of basic magnesium carbonate, catalyst components and metal foam, wherein the basic magnesium carbonate is a carrier for absorbing NOx, the catalyst components are composed of Fe2TiO5, Zn and ZnO, and the metal foam is a conductive substrate.

7. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: Also includes: Before the carbon dioxide gas source is input into the first reaction chamber / the second reaction chamber, the water vapor content of the carbon dioxide gas source is detected. If the water vapor content is insufficient, a certain amount of water vapor is input into the carbon dioxide gas source.

8. The method for removing NOx from carbon dioxide gas according to claim 1, characterized in that: A conductive catalyst adsorbent is filled between the first anode plate / first cathode plate and the first reaction chamber on both sides; and / or, Conductive catalyst adsorbent is filled between the second anode plate / second cathode plate and the second reaction chamber on both sides.

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