An integrated flue gas carbon dioxide capture and conversion system that synergizes CO, HC, and NO x Catalytic purification method

Abstract

The present invention provides a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x The catalytic purification method belongs to the technical field of flue gas purification. The present invention uses CeNiCa-based composite materials to capture and convert flue gas after pretreatment. During the capture process, when the flue gas flows through the composite material, carbon dioxide is adsorbed by the adsorbent to form carbonates, nitrogen oxides are adsorbed by the adsorbent to form nitrates, carbon monoxide and hydrocarbons are catalytically oxidized to generate carbon dioxide under the action of the catalyst, and the generated carbon dioxide is also adsorbed to form carbonates; hydrogen is introduced into the conversion process for catalytic reaction, and the adsorbed carbonate is catalytically reduced to methane, thereby realizing the resource utilization of the captured CO2, and the adsorbed nitrate is catalytically reduced to nitrogen, thereby realizing the purification of flue gas; the entire reaction can be realized in the same device, and it has the functions of CO2 capture and pollutant purification at the same time, and the system is simple and compact.

Description

Technical Field

[0001] The present invention relates to the field of flue gas purification technology, in particular to a method for capturing and converting flue gas carbon dioxide in an integrated manner to synergize CO, HC, NO x Catalytic purification method. Background Art

[0002] The high-temperature flue gas from the combustion device contains greenhouse gas carbon dioxide (CO2) and various gaseous pollutants, such as hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO x ), in order to achieve low-carbon and environmentally friendly emission requirements, it is necessary to treat CO2 and pollutants in the flue gas. Existing post-combustion CO2 capture technologies are mainly based on chemical solution absorption and solid chemical adsorption. Taking the solid chemical adsorption method using CaO solid particles as an adsorbent as an example, CO2 reacts with CaO to generate CaCO3 during the adsorption process. After adsorption, CaCO3 is calcined at high temperature to about 800°C, and CaCO3 is decomposed into CaO and CO2, that is, a high concentration of CO2 is obtained, which can be subsequently sealed or converted for utilization. Gaseous pollutants in flue gas are usually removed by catalytic methods. Through the catalytic reaction of flue gas and solid catalysts, pollutants are converted into pollution-free gases. For example, CO and HC can be converted into CO2 by catalytic oxidation, and NO x Selective catalytic reduction (SCR) can be used to reduce CO, HC and NO to nitrogen, or three-way catalysis (TWC) can be used to simultaneously reduce CO, HC and NO to nitrogen. x The reaction is CO2 and N2. However, in the traditional CO2 capture process, the desorption / desorption of the absorbent / adsorbent, CO2 purification, and catalytic conversion all consume a lot of energy and the system is complex, which greatly restricts the promotion and application of CO2 capture and utilization technology. At the same time, when considering the purification of flue gas pollutants, the flue gas post-treatment system composed of CO2 capture and conversion and pollutant catalytic purification is very complicated. Therefore, a simple method of CO2 capture and conversion and pollutant catalytic purification is urgently needed. Summary of the invention

[0003] The purpose of the present invention is to provide a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x Catalytic purification method. The method provided by the present invention is simple and has excellent purification effects on carbon dioxide and pollutants.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x The catalytic purification method comprises the following steps:

[0006] (1) pretreating a CeNiCa-based composite material in a mixed gas to obtain a pretreated CeNiCa-based composite material; the CeNiCa-based composite material is a composite material of cerium oxide, nickel oxide, calcium oxide and a third metal oxide; the third metal oxide includes magnesium oxide, copper oxide or zirconium oxide; the mixed gas is nitrogen and hydrogen; the pretreatment temperature is 450-550° C.;

[0007] (2) capturing the flue gas through the pretreated CeNiCa-based composite material obtained in step (1) to obtain a captured saturated material;

[0008] (3) hydrogen is introduced into the captured saturated material obtained in step (2) for catalytic conversion to obtain purified gas.

[0009] Preferably, the method for preparing the CeNiCa-based composite material in step (1) comprises the following steps:

[0010] a. Mix calcium salt, nickel salt, cerium salt, third metal salt, water and citric acid, carry out complex reaction and then evaporate to obtain a colloidal substance;

[0011] b. Drying the colloidal substance obtained in step a to obtain an intermediate product;

[0012] c. calcining the intermediate product obtained in step b to obtain a CeNiCa-based composite material.

[0013] Preferably, in step a, the molar ratio of calcium ions in the calcium salt, nickel ions in the nickel salt, cerium ions in the cerium salt and the third metal ions in the third metal salt is 1:(0.1-0.2):(0.1-0.5):(0.01-0.3).

[0014] Preferably, in step a, the ratio of the total amount of calcium ions in the calcium salt, nickel ions in the nickel salt, cerium ions in the cerium salt and the third metal ions in the third metal salt to the amount of citric acid is 1:(0.9-1.1).

[0015] Preferably, the temperature of the complexation reaction in step a is 20-30° C., and the time of the complexation reaction is 3-5 hours.

[0016] Preferably, the evaporation temperature in step a is 70-90°C.

[0017] Preferably, the drying temperature in step b is 100-150° C., and the drying time is 10-15 hours.

[0018] Preferably, the calcination temperature in step c is 500-600° C., the calcination time is 3-5 hours, and the heating rate to the calcination temperature is 4-6° C. / min.

[0019] Preferably, the capture temperature in step (2) is 400-500°C, the capture pressure is 0.5-2 atm, and the space velocity during capture is 20000-30000 h -1 .

[0020] Preferably, the temperature of the catalytic conversion in step (3) is 400-500°C, the pressure of the catalytic conversion is 0.5-2 atm, and the space velocity during the catalytic conversion is 5000-8000 h -1 .

[0021] The present invention provides a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x The catalytic purification method comprises the following steps: (1) pre-treating a CeNiCa-based composite material in a mixed gas to obtain a pre-treated CeNiCa-based composite material; the CeNiCa-based composite material is a composite material of cerium oxide, nickel oxide, calcium oxide and a third metal oxide; the third metal oxide comprises magnesium oxide, copper oxide or zirconium oxide; the mixed gas is nitrogen and hydrogen; the pre-treatment temperature is 450-550°C; (2) capturing flue gas through the pre-treated CeNiCa-based composite material obtained in step (1) to obtain a captured saturated material; and (3) introducing hydrogen into the captured saturated material obtained in step (2) for catalytic conversion to obtain purified gas. The present invention uses a composite material of cerium oxide, nickel oxide, calcium oxide and a third metal oxide to capture and catalytically convert flue gas after pretreatment. After the pretreatment, the nickel oxide in the composite material is reduced to nickel element as a catalyst, and the calcium oxide is used as an adsorbent. The composite material has both adsorption and catalytic functions. The cerium oxide and the third metal oxide are reduced to low-valent oxides as doping components to improve the catalytic activity of the composite material. During the capture process, when the flue gas flows through the composite material, carbon dioxide is adsorbed by the adsorbent to form carbonates, nitrogen oxides have stronger acidity than carbon dioxide, and are adsorbed by the adsorbent to form nitrates, carbon monoxide and hydrocarbons are catalytically oxidized to generate carbon dioxide under the action of the catalyst, and the generated carbon dioxide is also adsorbed to form carbonates; during the catalytic conversion process, hydrogen is introduced for catalytic reaction, and the adsorbed carbonate is catalytically reduced to methane and water, thereby realizing the resource utilization of the adsorbed CO2, and the adsorbed nitrate is catalytically reduced to nitrogen, thereby realizing the purification of the flue gas; the entire reaction can be realized in the same device, the system is more compact, and has the functions of CO2 capture and pollutant purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The invention provides a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x Schematic diagram of the catalytic purification method;

[0023] Figure 2 The invention provides a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x The capture and conversion process of CeNiCa-based composite materials in catalytic purification methods;

[0024] Figure 3 The carbon capture amount, methane production, conversion rate and methane selectivity in the three capture and conversion processes in Example 4 of the present invention;

[0025] Figure 4 This is the infrared spectrum of the purified gas obtained in step (3) of Example 4 of the present invention;

[0026] Figure 5 This is the mass spectrum of the purified gas obtained in step (3) of Example 4 of the present invention. DETAILED DESCRIPTION

[0027] The present invention provides a flue gas carbon dioxide capture and conversion integrated synergistic CO, HC, NO x The catalytic purification method comprises the following steps:

[0028] (1) pretreating a CeNiCa-based composite material in a mixed gas to obtain a pretreated CeNiCa-based composite material; the CeNiCa-based composite material is a composite material of cerium oxide, nickel oxide, calcium oxide and a third metal oxide; the third metal oxide includes magnesium oxide, copper oxide or zirconium oxide; the mixed gas is nitrogen and hydrogen; the pretreatment temperature is 450-550° C.;

[0029] (2) capturing the flue gas through the pretreated CeNiCa-based composite material obtained in step (1) to obtain a captured saturated material;

[0030] (3) hydrogen is introduced into the captured saturated material obtained in step (2) for catalytic conversion to obtain purified gas.

[0031] The invention pretreats the CeNiCa-based composite material in a mixed gas to obtain the pretreated CeNiCa-based composite material.

[0032] In the present invention, the preparation method of the CeNiCa-based composite material comprises the following steps:

[0033] a. Mix calcium salt, nickel salt, cerium salt, third metal salt, water and citric acid, carry out complex reaction and then evaporate to obtain a colloidal substance;

[0034] b. Drying the colloidal substance obtained in step a to obtain an intermediate product;

[0035] c. calcining the intermediate product obtained in step b to obtain a CeNiCa-based composite material.

[0036] The present invention preferably mixes calcium salt, nickel salt, cerium salt, third metal salt, water and citric acid, performs complexation reaction and then evaporates to obtain a colloidal substance.

[0037] In the present invention, the calcium salt preferably includes calcium nitrate or calcium oxalate; the nickel salt preferably includes nickel nitrate; the cerium salt preferably includes cerium nitrate; the third metal salt preferably includes magnesium salt, copper salt or zirconium salt; the magnesium salt is preferably magnesium nitrate; the copper salt is preferably copper nitrate; the zirconium salt is preferably zirconium nitrate. In the present invention, the calcium salt subsequently forms calcium oxide as an adsorbent; the nickel salt subsequently forms nickel oxide; the cerium salt subsequently forms cerium oxide; and the third metal salt subsequently forms a third metal oxide.

[0038] In the present invention, the molar ratio of calcium ions in the calcium salt, nickel ions in the nickel salt, cerium ions in the cerium salt and the third metal ions in the third metal salt is preferably 1: (0.1-0.2): (0.1-0.5): (0.01-0.3); the molar ratio of the calcium salt and water is preferably 1: (180-220), more preferably 1: 200. If the nickel content is too low, the catalytic sites are insufficient, and if the content is too high, the carbon capture amount will be reduced; if the cerium content and the third metal salt content are too low, the performance optimization is insufficient, and if the content is too high, the capture and conversion performance of the material will be reduced; the present invention limits the molar ratio of metal ions in the calcium salt, nickel salt, cerium salt and the third metal salt to the above range, which can increase the carbon capture amount and is also beneficial to the catalytic conversion process.

[0039] In the present invention, the ratio of the total amount of calcium ions in the calcium salt, nickel ions in the nickel salt, cerium ions in the cerium salt and the third metal ions in the third metal salt to the amount of citric acid is preferably 1: (0.9-1.1), more preferably 1: 1. In the present invention, the citric acid in the aqueous solution loses part of its protons to form citrate ions, which have lone pairs of electrons on multiple oxygen atoms and can form complexes with metal ions. The present invention limits the amount of citric acid to the above range. Too little citric acid results in incomplete complexation reaction, resulting in an increase in the particle size of the composite material. Too much citric acid results in too much carbon residue in the material after calcination, which is not conducive to capture and catalytic conversion.

[0040] In the present invention, the calcium salt, nickel salt, cerium salt, third metal salt, water and citric acid are preferably mixed in the following manner: firstly, the calcium salt, nickel salt, cerium salt, third metal salt and water are mixed, and then citric acid is added.

[0041] In the present invention, the temperature of the complex reaction is preferably 20-30°C; the time of the complex reaction is preferably 3-5h. The present invention limits the temperature and time of the complex reaction to the above ranges, so that the complex reaction can be fully carried out.

[0042] In the present invention, the evaporation temperature is preferably 70-90° C., more preferably 80° C. The present invention has no particular limitation on the evaporation time, and the water can be evaporated to obtain a gelatinous substance.

[0043] After obtaining the colloid substance, the present invention preferably dries the colloid substance to obtain an intermediate product.

[0044] In the present invention, the drying temperature is preferably 100-150°C, more preferably 120°C; the drying time is preferably 10-15h, more preferably 12h. In the present invention, during the drying process, the residual water in the colloid will evaporate. Due to the strong viscosity of the colloid, the water vapor cannot directly overflow the system, so the colloid expands. When it expands to a certain extent, the top layer of the material ruptures to release and remove the water vapor. This process is conducive to the formation of nanomaterials and promotes smaller material particle sizes.

[0045] After drying, the present invention preferably grinds the dried product to obtain an intermediate product.

[0046] The present invention has no special limitation on the crushing operation, and the crushing technical scheme well known to those skilled in the art can be adopted.

[0047] After obtaining the intermediate product, the present invention preferably calcines the intermediate product to obtain a CeNiCa-based composite material.

[0048] In the present invention, the calcination temperature is preferably 500-600°C, more preferably 550°C; the calcination time is preferably 3-5h, more preferably 4h; the heating rate to the calcination temperature is preferably 4-6°C / min, more preferably 5°C / min. In the present invention, during the calcination process, the intermediate product reacts to form a composite material of calcium oxide, nickel oxide, cerium oxide and a third metal oxide. The present invention limits the calcination temperature and time within the above range. If the temperature is too low, the intermediate product cannot be fully reacted, and if the carbon content in the calcined material is too high, its performance will be inhibited. If the temperature is too high, the material will agglomerate and sinter, and the catalytic performance of the material will be greatly reduced.

[0049] After the calcination is completed, the present invention preferably cools the calcined product to obtain a CeNiCa-based composite material.

[0050] The present invention has no special limitation on the cooling operation, and any cooling technical solution well known to those skilled in the art may be used.

[0051] In the present invention, the mixed gas is nitrogen and hydrogen; the volume ratio of hydrogen to nitrogen in the mixed gas is preferably 1:1.

[0052] In the present invention, the pretreatment temperature is 450-550°C, preferably 500°C; the pretreatment time is preferably 1 hour; the pretreatment pressure is preferably normal pressure; the space velocity during the pretreatment is preferably 78000h -1 .

[0053] In the present invention, the role of the pretreatment is to reduce the nickel oxide in the CeNiCa-based composite material to nickel element, reduce the cerium oxide and the third metal oxide to low-valent oxides, and remove the residual carbon in the preparation process of the composite material.

[0054] After obtaining the pretreated CeNiCa-based composite material, the present invention captures the flue gas through the pretreated CeNiCa-based composite material to obtain a captured saturated material.

[0055] The present invention has no special limitation on the source of the flue gas, and combustion flue gas well known to those skilled in the art can be used. In the present invention, the components in the flue gas preferably include one or more of carbon dioxide, carbon monoxide, hydrocarbons, nitrogen oxides, nitrogen and oxygen; the volume fraction of carbon dioxide in the flue gas is preferably 10-20%.

[0056] In the present invention, the capture temperature is preferably 400-500°C, more preferably 450°C; the capture pressure is preferably 0.5-2atm, more preferably 1atm; the space velocity during capture is preferably 20000-30000h -1 , preferably 24000h -1 The present invention has no particular limitation on the capture time, as long as the CeNiCa-based composite material reaches saturation.

[0057] In the present invention, during the capture process, when the flue gas flows through the composite material, carbon dioxide is adsorbed by the adsorbent to form carbonates, nitrogen oxides have a stronger acidity than carbon dioxide and are adsorbed by the adsorbent to form nitrates, and carbon monoxide and hydrocarbons are catalytically oxidized to form carbon dioxide under the action of the catalyst, and the generated carbon dioxide is also adsorbed to form carbonates.

[0058] After obtaining the captured saturated material, the present invention introduces hydrogen into the captured composite material for catalytic conversion to obtain purified gas.

[0059] In the present invention, the hydrogen is preferably introduced in the form of a mixture of hydrogen and nitrogen; the volume fraction of hydrogen in the mixture of hydrogen and nitrogen is preferably 30-50%, more preferably 40%. In the present invention, the temperature of the catalytic conversion is preferably 400-500°C, more preferably 450°C; the pressure of the catalytic conversion is preferably 0.5-2atm, more preferably 1atm; the time of the catalytic conversion is preferably 0.5-2h, more preferably 1h; the space velocity during the catalytic conversion is preferably 5000-8000h -1 , preferably 6000h -1 .

[0060] The present invention uses a composite material of nickel oxide, calcium oxide, cerium oxide and a third metal oxide to capture and catalytically convert flue gas after pretreatment. After the pretreatment, the nickel oxide in the composite material is reduced to nickel element as a catalyst, and the calcium oxide is used as an adsorbent. The composite material has both adsorption and catalytic functions. The cerium oxide and the third metal oxide are reduced to low-valent oxides as doping components to improve the catalytic activity of the composite material. During the capture process, when the flue gas flows through the composite material, carbon dioxide is adsorbed by the adsorbent to form carbonates, nitrogen oxides have stronger acidity than carbon dioxide, and are adsorbed by the adsorbent to form nitrates, carbon monoxide and hydrocarbons are catalytically oxidized to generate carbon dioxide under the action of the catalyst, and the generated carbon dioxide is also adsorbed to form carbonates; during the catalytic conversion process, hydrogen is introduced for catalytic reaction, and the adsorbed carbonates are catalytically reduced to usable products such as methane and carbon monoxide, and water is generated at the same time, thereby realizing resource utilization of the captured CO2, and the adsorbed nitrates are catalytically reduced to nitrogen, etc., thereby realizing purification of the flue gas; the entire reaction can be realized in the same device, and the CO2 capture and pollutant purification functions are simultaneously provided, and the system is simple and compact.

[0061] The device for capture and catalytic conversion of the present invention is not particularly limited, and a device familiar to those skilled in the art can be used. The present invention preferably loads the CeNiCa-based composite material into a quartz tube, fixes both ends of the composite material with quartz wool, and detects its air tightness. The present invention preferably connects a detection instrument to the outlet end of the reaction device to detect the product composition or calculate the carbon capture amount, methane production, conversion rate, and methane selectivity during the reaction process. In the present invention, the detection instrument preferably includes an infrared detection instrument and a mass spectrometer.

[0062] In the present invention, the carbon capture amount Methane production Conversion rate Methane selectivity The calculation formula is preferably as follows:

[0063]

[0064]

[0065]

[0066]

[0067]

[0068] Where W, F CO,out , t0, t1 and t2 are the sample mass, the molar flow rates of CH4, CO and CO2 in the outlet gas, the molar flow rate of CO2 in the inlet gas, the end time of carbon capture (5 min), the start time of H2 supply and the end time of methanogenesis, respectively.

[0069] The invention provides an integrated flue gas carbon dioxide capture and conversion system that synergizes CO, HC, NO x The schematic diagram of the catalytic purification method is preferably as follows Figure 1 As shown: the high-temperature flue gas emitted by the emission source is captured by the composite material, and then hydrogen is introduced for catalytic conversion to obtain a methane / nitrogen / water and carbon dioxide / nitrogen oxide-free mixed gas.

[0070] The invention provides an integrated flue gas carbon dioxide capture and conversion system that synergizes CO, HC, NO x The capture process and catalytic conversion process of CeNiCa-based composite materials in the catalytic purification method are as follows Figure 2 In the capture process, nitrogen oxides, carbon dioxide, carbon monoxide, hydrocarbons and oxygen form nitrates and carbonates. Under the action of hydrogen in the catalytic conversion process, nitrates form nitrogen and carbonates form methane and water.

[0071] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] Example 1

[0073] (1) The CeNiCuCa composite material is placed in a quartz tube, both ends of the composite material are fixed with quartz wool, and the air tightness is tested. The composite material is pretreated with a mixed gas of hydrogen and nitrogen at 500° C. for 1 h, wherein the volume ratio of hydrogen to nitrogen in the mixed gas of hydrogen and nitrogen is 1:1; the pretreatment pressure is normal pressure; the space velocity during the pretreatment is 78000 h -1 ;

[0074] The preparation method of CeNiCuCa composite material is as follows:

[0075] a. Mix calcium nitrate, nickel nitrate, cerium nitrate, copper nitrate and deionized water, then add citric acid, stir at room temperature for 4 hours to carry out complex reaction, and then evaporate the water at 80° C. to obtain a colloidal substance; the molar ratio of calcium ions in calcium nitrate, nickel ions in nickel nitrate, cerium ions in cerium nitrate and copper ions in copper nitrate is 1:0.14:0.1:0.07; the total molar ratio of calcium ions in calcium nitrate, nickel ions in nickel nitrate, cerium ions in cerium nitrate and copper ions in copper nitrate to the molar ratio of citric acid is 1:1;

[0076] b. Drying the colloidal substance obtained in step a at 120° C. for 12 h to obtain an intermediate product;

[0077] c. calcining the intermediate product obtained in step b at 550° C. for 4 h at a heating rate of 5° C. / min, and cooling to obtain a CeNiCuCa composite material;

[0078] (2) At 450°C, 1 atm, space velocity 24000 h -1 Under the condition, a CO / air mixture (the volume concentration of CO in the mixture is 4000ppm) is introduced for capture, and the calculated CO conversion rate is close to 100%.

[0079] Example 2

[0080] (1) Step (1) is the same as in Example 1;

[0081] (2) At 450°C, 1 atm, space velocity 24000 h -1 Under the conditions of C3H8 / C3H6 / air mixture (the volume concentration of C3H8 in the mixture is 1900ppm, and the volume concentration of C3H6 is 1600ppm) was introduced for capture, and the conversion rate of hydrocarbons was calculated to be 82%.

[0082] Example 3

[0083] (1) Step (1) is the same as in Example 1;

[0084] (2) At 450°C, 1 atm, space velocity 24000 h -1 Under the condition, a CO2 / NO2 / N2 mixed gas (the volume concentration of CO2 in the mixed gas is 10%, and the volume concentration of NO2 is 500ppm) is introduced for capture to obtain a saturated material after capture;

[0085] (3) At 450°C, 1 atm, space velocity 6000 h -1A H2 / N2 mixed gas (the volume fraction of hydrogen in the mixed gas is 40%) is introduced into the captured saturated material for catalytic conversion. The catalytic conversion time is 1 hour to obtain purified gas.

[0086] According to calculations, nitrogen dioxide is completely adsorbed during the capture process and is released mainly as ammonia and nitrogen during the conversion process.

[0087] Example 4

[0088] (1) Step (1) is the same as in Example 1;

[0089] (2) At 450°C, 1 atm, space velocity 24000 h -1 Under the condition, a CO2 / N2 mixed gas (the volume fraction of CO2 in the mixed gas is 10%) is introduced for capture to obtain a saturated material after capture;

[0090] (3) At 450°C, 1 atm, space velocity 6000 h -1 A H2 / N2 mixed gas (the volume fraction of hydrogen in the mixed gas is 40%) is introduced into the captured saturated material to perform catalytic conversion for 1 hour to obtain purified gas;

[0091] (4) Repeat steps (2) and (3) twice, i.e., perform three captures and three conversions.

[0092] The carbon capture amount, methane production, conversion rate and methane selectivity in the three capture and conversion processes in Example 4 are as follows: Figure 3 As shown. Figure 3 It can be seen that the carbon capture amount in the first capture and conversion process is 11.1mmol / g, the methane production is 9.88mmol / g, the conversion rate is 88.78%, and the methane selectivity is 99.91%. The carbon capture amount in the second capture and conversion process is 10.96mmol / g, the methane production is 10.18mmol / g, the conversion rate is 93.25%, and the methane selectivity is 99.59%. The carbon capture amount in the third capture and conversion process is 10.66mmol / g, the methane production is 10.24mmol / g, the conversion rate is 96.50%, and the methane selectivity is 99.51%. The average carbon capture amount in the three capture and conversion processes is 10.75mmol / g, the average methane production is 10.10mmol / g, the average conversion rate is 92.84%, and the average methane selectivity is 99.67%.

[0093] The purified gas obtained in step (3) of Example 4 was passed into an infrared gas cell for component analysis. The infrared spectrum obtained was as follows: Figure 4 As shown. Figure 4 It can be seen that the product contains NH3 and CH4.

[0094] The purified gas obtained by replacing the background gas under the conditions of step (3) of Example 4 with argon gas was passed into a mass spectrometer for component analysis. The mass spectrum obtained is as follows: Figure 5 As shown. Figure 5 It can be seen that the product contains N2 and N2O.

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An integrated flue gas carbon dioxide capture and conversion system to synergize CO, HC, and NO x The catalytic purification method comprises the following steps: (1) pretreating a CeNiCa-based composite material in a mixed gas to obtain a pretreated CeNiCa-based composite material; the CeNiCa-based composite material is a composite material of cerium oxide, nickel oxide, calcium oxide and a third metal oxide; the third metal oxide includes magnesium oxide, copper oxide or zirconium oxide; the mixed gas is nitrogen and hydrogen; the pretreatment temperature is 450-550° C.; The preparation method of the CeNiCa-based composite material in step (1) comprises the following steps: a. Mix calcium salt, nickel salt, cerium salt, third metal salt, water and citric acid, carry out complex reaction and then evaporate to obtain a colloidal substance; b. Drying the colloidal substance obtained in step a to obtain an intermediate product; c. calcining the intermediate product obtained in step b to obtain a CeNiCa-based composite material; In step a, the molar ratio of the calcium ions in the calcium salt, the nickel ions in the nickel salt, the cerium ions in the cerium salt and the third metal ions in the third metal salt is 1:(0.1-0.2):(0.1-0.5):(0.01-0.3); (2) capturing the flue gas through the pretreated CeNiCa-based composite material obtained in step (1) to obtain a captured saturated material; (3) hydrogen is introduced into the captured saturated material obtained in step (2) for catalytic conversion to obtain purified gas.

2. The method according to claim 1, characterized in that In step a, the ratio of the total amount of calcium ions in the calcium salt, nickel ions in the nickel salt, cerium ions in the cerium salt and the third metal ions in the third metal salt to the amount of citric acid is 1:(0.9-1.1).

3. The method according to claim 1, characterized in that: The temperature of the complexation reaction in step a is 20-30° C., and the time of the complexation reaction is 3-5 hours.

4. The method according to claim 1, characterized in that: The evaporation temperature in step a is 70-90°C.

5. The method according to claim 1, characterized in that The drying temperature in step b is 100-150° C. and the drying time is 10-15 hours.

6. The method according to claim 1, characterized in that The calcination temperature in step c is 500-600° C., the calcination time is 3-5 hours, and the heating rate to the calcination temperature is 4-6° C. / min.

7. The method according to claim 1, characterized in that In the step (2), the capture temperature is 400-500°C, the capture pressure is 0.5-2 atm, and the space velocity during capture is 20000-30000 h -1 .

8. The method according to claim 1, characterized in that: The temperature of the catalytic conversion in step (3) is 400-500° C., the pressure of the catalytic conversion is 0.5-2 atm, and the space velocity during the catalytic conversion is 5000-8000 h -1 .

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