High-selectivity anti-carbon-deposition CO oxidation catalyst and preparation method thereof

Abstract

The invention provides a high-selectivity anti-carbon-deposition CO oxidation catalyst and a preparation method thereof. The CO oxidation catalyst comprises a carrier, an active component loaded on the surface and / or in the carrier, and an auxiliary agent, wherein the active component comprises a noble metal element, and the auxiliary agent comprises a non-noble metal element; by taking the total mass of the carrier as 100%, the content of the auxiliary agent is less than 10%, preferably 3-6%; the total mass of the carrier and the auxiliary agent is 100%, and the content of the active component is less than 1.5%, preferably 0.5-1.5%. The CO oxidation catalyst disclosed by the invention has the characteristics of NOx resistance, carbon deposition resistance, difficulty in oxidizing NO, high CO catalytic combustion activity and the like, and has excellent CO catalytic combustion performance, especially the performance of catalytic combustion of steel sintering flue gas CO.

Description

Technical Field

[0001] The present invention relates to a highly selective anti-carbon deposition CO oxidation catalyst and a preparation method thereof, and in particular to a catalyst used for catalytic combustion of CO in steel sintering flue gas and a preparation method thereof, belonging to the technical field of air pollution control. Background Art

[0002] CO is one of the main air pollutants today. It is a colorless, odorless, toxic gas that can not only directly endanger people's lives and health, but also react with VOCs (volatile organic compounds) and NO under light conditions. x Photochemical reactions produce ozone, causing ozone pollution. With the continuous deepening of air pollution prevention and control work, the quality of ambient air has continued to improve, and the emission requirements for CO have become increasingly stringent. Steel sintering flue gas contains a large amount of CO, and the CO content is basically 6000-10000 mg / Nm 3 , and its governance has become a key issue of concern to the world's steel companies.

[0003] At present, due to the complex atmosphere of steel sintering flue gas and the lack of effective terminal treatment technology, the emission reduction methods of CO in steel sintering flue gas are mainly source control and process control. After source control and process control, the CO content in sintering flue gas is still 1000mg / Nm 3 Therefore, it is necessary to develop efficient terminal control technology, which can completely solve the problem of high CO emissions in the steel industry. At present, the terminal treatment technology for CO emissions from steel sintering flue gas has become a research and development hotspot.

[0004] The catalytic combustion method has attracted much attention due to its high removal rate, no secondary pollution, low energy consumption, high safety of flameless oxidation, simple process and wide application range. The catalytic combustion method has become one of the main methods for controlling emissions of VOCs, CO and other substances in many industries. The CO content in steel sintering flue gas is high, and a large amount of heat can be released after catalytic combustion. It is necessary to make full use of this heat. Placing the CO catalytic combustion device in front of the steel sintering flue gas SCR denitrification device can provide a large amount of heat for the SCR denitrification reaction, which can effectively save energy for the enterprise.

[0005] However, the atmosphere of steel sintering flue gas is complex and contains a small amount of VOCs. The catalytic combustion of VOCs is much more difficult than CO. Under CO catalytic combustion conditions, unoxidized VOCs will be deposited on the surface of the catalytic combustion catalyst. Long-term operation will cause the catalyst to be deactivated by carbon deposition. Moreover, placing the CO catalytic combustion device before the SCR denitrification device for steel sintering flue gas to supplement the heat for the SCR denitrification reaction will cause the presence of NO in the CO catalytic combustion conditions. x , NO xIt will affect the catalytic combustion of CO, and a large amount of NO will be oxidized into NO2, making the subsequent SCR denitrification more difficult.

[0006] Therefore, developing a novel NO-resistant x Highly active and highly selective CO oxidation catalysts that are resistant to carbon deposition and not easy to oxidize NO have become technical issues that need to be solved urgently. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In view of the technical problems existing in the prior art, the present invention first provides a highly selective anti-carbon deposition CO oxidation catalyst. The CO oxidation catalyst of the present invention has the advantages of anti-NO x , anti-carbon deposition, not easy to oxidize NO, and high CO catalytic combustion activity.

[0009] Furthermore, the present invention also provides a method for preparing a CO oxidation catalyst, which is simple and effective, has easy-to-obtain raw materials, is easy to operate, and can achieve mass production.

[0010] Furthermore, the CO oxidation catalyst of the present invention can be used in the catalytic combustion of flue gas containing CO, especially in the catalytic combustion of CO in steel sintering flue gas.

[0011] Solutions for solving problems

[0012] [1] A CO oxidation catalyst comprising a carrier, an active ingredient supported on the surface and / or inside of the carrier, and an auxiliary agent; wherein:

[0013] The active ingredient includes a noble metal element, and the auxiliary agent includes a non-noble metal element;

[0014] Based on the total mass of the carrier as 100%, the content of the auxiliary agent is less than 10%, preferably 3-6%;

[0015] Based on the total mass of the carrier and the auxiliary agent being 100%, the content of the active ingredient is less than 1.5%, preferably 0.5-1.5%.

[0016] [2] The CO oxidation catalyst according to [1] above, wherein the noble metal element includes platinum and / or palladium; and / or

[0017] The support includes a cerium oxide support and / or an aluminum oxide support.

[0018] [3] The CO oxidation catalyst according to [1] or [2] above, wherein the additive comprises a first non-precious metal element and a second non-precious metal element, and preferably, the mass ratio of the first non-precious metal element to the second non-precious metal element is 0.2 to 3:1.

[0019] [4] The CO oxidation catalyst according to [3] above, wherein the first non-precious metal element includes magnesium and / or sodium, and the second non-precious metal element includes one or a combination of two or more of vanadium, tungsten and molybdenum.

[0020] [5] The CO oxidation catalyst according to any one of [1] to [4] above, wherein the specific surface area of ​​the CO oxidation catalyst is 25 m 2 / g or more, pore volume is 0.1cm 3 / g or above.

[0021] [6] A method for preparing a CO oxidation catalyst according to any one of [1] to [5] above, comprising the following steps:

[0022] dissolving an auxiliary agent precursor in a solvent to obtain an auxiliary agent precursor solution;

[0023] impregnating the support once in the auxiliary agent precursor solution to obtain a first impregnation product;

[0024] performing a drying process on the first impregnation product to obtain a first dried product;

[0025] calcining the first dried product to obtain a first calcined product;

[0026] dissolving an active ingredient precursor in a solvent to obtain an active ingredient precursor solution;

[0027] impregnating the first calcined product in an active ingredient precursor solution for a second time to obtain a second impregnated product;

[0028] performing secondary drying on the second impregnation product to obtain a second dried product;

[0029] The second dried product is subjected to a secondary calcination treatment to obtain a CO oxidation catalyst.

[0030] [7] The preparation method according to [6] above, wherein the auxiliary agent precursor comprises one or a combination of two or more of magnesium salt, sodium salt, vanadium salt, tungsten salt and molybdenum salt; the active ingredient precursor comprises one or a combination of two or more of platinum salt, rubidium salt, silver salt, ruthenium salt and palladium salt; and / or,

[0031] The first impregnation and / or the second impregnation are equal volume impregnations.

[0032] [8] The preparation method according to [6] or [7] above, wherein the temperature of the primary drying treatment and / or the secondary drying treatment is 50-90°C, and the time of the primary drying treatment and / or the secondary drying treatment is 3-9 hours.

[0033] [9] The preparation method according to any one of [6] to [8] above, wherein the temperature of the primary calcination treatment and / or the secondary calcination treatment is 500-700°C, and the time of the primary calcination treatment and / or the secondary calcination treatment is 1-3 hours; preferably, the primary calcination treatment and / or the secondary calcination treatment is carried out in an air atmosphere.

[0034]

[10] Use of the CO oxidation catalyst according to any one of [1] to [5] above in the catalytic combustion of CO, preferably in the catalytic combustion of CO in steel sintering flue gas.

[0035] Effects of the Invention

[0036] The CO oxidation catalyst of the present invention has NO resistance x It has the characteristics of anti-carbon deposition, not easy to oxidize NO, high CO catalytic combustion activity, etc. It has excellent performance in catalytic combustion of CO, especially the performance in catalytic combustion of CO in steel sintering flue gas.

[0037] Furthermore, the preparation method of the CO oxidation catalyst of the present invention is simple and effective, the raw materials are easy to obtain, the operation is convenient, and mass production can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is an XRD comparison diagram of the CO oxidation catalysts of Examples 1-3 of the present invention and the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2.

[0039] Figure 2 It is a toluene-TPD comparison chart of the CO oxidation catalysts of Examples 1-3 of the present invention and the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2.

[0040] Figure 3 It is a performance diagram of the catalytic combustion of CO reaction of the CO oxidation catalysts of Examples 1-3 of the present invention and the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2 in the atmosphere of steel sintering flue gas.

[0041] Figure 4 It is a performance diagram of NO oxidation reaction when the CO oxidation catalysts of Examples 1-3 of the present invention and the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2 catalyze the combustion of CO in the atmosphere of steel sintering flue gas.

[0042] Figure 5This is a transmission electron microscope (TEM) image of the CO oxidation catalyst of Example 1 of the present invention. DETAILED DESCRIPTION

[0043] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0044] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0045] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0046] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0047] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0048] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0049] In this specification, unless otherwise specified, the word "multiple" in "multiple", "multiple", "plurality", etc. means a numerical value of 2 or more.

[0050] In the present specification, "optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes cases where the event occurs and cases where it does not occur.

[0051] <First aspect>

[0052] The first aspect of the present invention provides a CO oxidation catalyst, which comprises a carrier, an active component supported on the carrier and an auxiliary agent; wherein:

[0053] The active ingredient includes a noble metal element, and the auxiliary agent includes a non-noble metal element;

[0054] Based on the total mass of the carrier as 100%, the content of the active ingredient is less than 1.5%, preferably 0.5-1.5%; the content of the auxiliary agent is less than 10%, preferably 3-6%.

[0055] The CO oxidation catalyst of the present invention has NO resistance x It has the characteristics of anti-carbon deposition, not easy to oxidize NO, high CO catalytic combustion activity, etc. It has excellent performance in catalytic combustion of CO, especially the performance in catalytic combustion of CO in steel sintering flue gas.

[0056] The specific surface area of ​​the CO oxidation catalyst of the present invention is 25m 2 / g or more, pore volume is 0.1cm 3 / g or more. Due to the presence of the additive, the specific surface area and pore volume of the CO oxidation catalyst will be reduced to a certain extent. Even if the specific surface area and pore volume are reduced, the catalyst of the present application still has a more excellent catalytic combustion CO performance.

[0057] Carrier

[0058] The carrier of the present invention has a porous structure and a certain specific surface area. The present invention does not specifically limit the carrier, and it can be some carriers commonly used in the art, such as: cerium oxide carrier and / or aluminum oxide carrier. Preferably, in order to better realize the function of the CO oxidation catalyst of the present invention, the present invention preferably uses a cerium oxide carrier. The cerium oxide carrier has unique oxygen storage and release properties and high-temperature rapid oxygen vacancy diffusion capacity, which can make the function of the CO oxidation catalyst of the present invention more effectively exerted. The cerium oxide carrier of the present invention has good oxygen storage and release properties and The redox properties show unique advantages in the catalytic oxidation combustion of CO when used as a catalyst support.

[0059] Additives

[0060] In the present invention, the auxiliary agent includes a non-precious metal element. The inventors of the present invention have found that by using a non-precious metal element as an auxiliary agent, the NO conversion rate can be reduced, thereby obtaining an anti-NO x , a CO oxidation catalyst that is resistant to carbon deposits and not prone to NO oxidation.

[0061] In some specific embodiments, based on the total mass of the carrier as 100%, the content of the additive is less than 10%, preferably 3-6%, for example: 1%, 2%, 3.5%, 4%, 4.5%, 5%, 5.5%, 7%, 8%, 9%, etc. When the content of the additive is less than 10%, the adsorption of VOCs and the oxidation of NO can be effectively reduced, but if the content of the additive is too high, the catalytic oxidation combustion performance of CO may be affected.

[0062] In some specific embodiments, the present invention preferably uses two different non-precious metal elements. Specifically, the auxiliary agent includes a first non-precious metal element and a second non-precious metal element. When the first non-precious metal element is used to modify the carrier, the first non-precious metal element can reduce the number of acid sites on the catalyst surface, reduce the acidity of the catalyst, thereby reducing the catalyst's adsorption capacity for VOCs, and making the catalyst have good anti-carbon deposition performance. When the second non-precious metal element is used to modify the carrier, the second non-precious metal element can promote the reaction of NO2 and CO to generate NO and CO2, thereby improving the catalyst's oxidation ability for CO, and improving the macroscopic selectivity, that is, CO is completely oxidized while NO is not oxidized.

[0063] Furthermore, in order to make the auxiliary agent play the most effective role, in the present invention, the mass ratio of the first non-precious metal element to the second non-precious metal element is 0.2 to 3: 1. When the mass ratio of the first non-precious metal element to the second non-precious metal element is 0.2 to 3: 1, the effects of the first non-precious metal element and the second non-precious metal element can be effectively exerted, and there is a synergistic effect between the two.

[0064] In some specific embodiments, considering that the effects of the first non-precious metal element and the second non-precious metal element can both be effectively exerted, the first non-precious metal element includes magnesium and / or sodium, and the second non-precious metal element includes one or a combination of two or more of vanadium, tungsten and molybdenum.

[0065] Active ingredients

[0066] The active component of the present invention includes precious metal elements. Precious metals have good catalytic activity. Therefore, the present invention uses precious metal elements to enable the CO oxidation catalyst to achieve catalytic combustion of CO.

[0067] In the present invention, taking into account the cost of the active ingredient, in the CO oxidation catalyst of the present invention, based on the total mass of the carrier and the additive as 100%, the content of the active ingredient is less than 1.5%, preferably 0.5-1.5%, for example: 0.2%, 0.3%, 0.4%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, etc.; Generally speaking, excellent catalytic combustion CO performance can be achieved with an active ingredient content of less than 1.5%.

[0068] In some specific embodiments, considering that the role of the precious metal elements can be effectively played, the precious metal elements include platinum and / or palladium.

[0069] <Second Aspect>

[0070] The second aspect of the present invention provides a method for preparing the CO oxidation catalyst according to the first aspect of the present invention, which comprises the following steps:

[0071] dissolving an auxiliary agent precursor in a solvent to obtain an auxiliary agent precursor solution;

[0072] impregnating the carrier in the auxiliary agent precursor solution to obtain a first impregnation product;

[0073] performing a drying process on the first impregnation product to obtain a first dried product;

[0074] calcining the first dried product to obtain a first calcined product;

[0075] dissolving an active ingredient precursor in a solvent to obtain an active ingredient precursor solution;

[0076] impregnating the first calcined product in an active ingredient precursor solution to obtain a second impregnated product;

[0077] performing secondary drying on the second impregnation product to obtain a second dried product;

[0078] The second dried product is subjected to a secondary calcination treatment to obtain a CO oxidation catalyst.

[0079] The CO oxidation catalyst of the present invention has NO resistance x It has the characteristics of anti-carbon deposition, not easy to oxidize NO, high CO catalytic combustion activity, etc. It has excellent performance in catalytic combustion of CO, especially the performance in catalytic combustion of CO in steel sintering flue gas.

[0080] Preparation of the first calcined product

[0081] The preparation method of the present invention first dissolves the auxiliary agent precursor in a solvent to obtain an auxiliary agent precursor solution. In the present invention, the auxiliary agent precursor may include one or a combination of two or more of magnesium salts, sodium salts, vanadium salts, tungsten salts and molybdenum salts. Specifically, the magnesium salt may be one or a combination of two or more of magnesium nitrate, magnesium acetate or magnesium chloride; the sodium salt may be one or a combination of two or more of sodium nitrate, sodium acetate and sodium chloride; the vanadium salt may be ammonium metavanadate; the tungsten salt may be ammonium metatungstate; the molybdenum salt may be one or a combination of two or more of molybdenum nitrate, molybdenum acetate and molybdenum chloride; the platinum salt may be one or a combination of two or more of platinum nitrate, platinum acetate and chloroplatinic acid.

[0082] In some specific embodiments, the auxiliary agent precursor includes a first auxiliary agent precursor and a second auxiliary agent precursor; the first auxiliary agent precursor includes magnesium salt and / or sodium salt, and the second auxiliary agent precursor includes one or a combination of two or more of vanadium salt, tungsten salt and molybdenum salt.

[0083] The present invention does not specifically limit the solvent used for dissolving the precursor of the auxiliary agent, and it can be a commonly used solvent in the art, such as water.

[0084] The present invention does not particularly limit the concentration of the additive precursor solution, which can generally be 1 to 3 mol / L, for example, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.5 mol / L, 2.8 mol / L, etc.

[0085] Next, the carrier is immersed in the auxiliary agent precursor solution to obtain a first impregnation product. For impregnation, the present invention preferably uses equal volume impregnation. The equal volume impregnation method generally determines the saturated water absorption of the carrier, that is, the water absorption rate, before impregnation. Then, an equal volume of the auxiliary agent precursor solution required for impregnation is prepared, and the carrier is immersed in the auxiliary agent precursor solution. The present invention does not specifically limit the method for determining the saturated water absorption, and it can be determined according to the method of the prior art, or it can be impregnated in equal volume according to the saturated water absorption provided in the product manual.

[0086] In the present invention, the immersion time of the carrier in the auxiliary agent precursor solution is not particularly limited, as long as equal volume immersion is achieved. Generally speaking, the immersion time in the auxiliary agent precursor solution can be 1-3 hours, for example: 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, etc.

[0087] Further, the first impregnation product is subjected to a drying treatment to obtain a first dried product. By performing the drying treatment, the solvent physically adsorbed on the surface can be removed. Specifically, in the present invention, the temperature of the first drying treatment is 50 to 90°C, for example: 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, etc.; the time of the first drying treatment is 3-9h, for example: 4h, 5h, 6h, 7h, 8h, etc.

[0088] Further, the first dried product is subjected to a calcination treatment to obtain a first calcined product. Through the calcination treatment, the auxiliary agent can be uniformly loaded on the surface and / or inside of the carrier in the form of oxides.

[0089] Specifically, the temperature of the primary calcination treatment is 500-700°C, for example: 550°C, 600°C, 650°C, etc.; the time of the primary calcination treatment is 1-3h, for example: 1.5h, 2h, 2.5h, etc. Preferably, the primary calcination treatment can be carried out in an air atmosphere. Specifically, the primary calcination treatment includes heating to 500-700°C and calcining for 1-3h at a heating rate of 1-20°C / min.

[0090] Preparation of CO oxidation catalyst

[0091] The active ingredient precursor is dissolved in a solvent to obtain an active ingredient precursor solution. In the present invention, the active ingredient precursor includes one or a combination of two or more of a platinum salt, a rubidium salt, a silver salt, a ruthenium salt, and a palladium salt. The platinum salt can be one or a combination of two or more of platinum nitrate, platinum acetate, chloroplatinic acid, etc. The rubidium salt can be one or a combination of two or more of rubidium chloride, rubidium carbonate, rubidium sulfate, etc. The silver salt can be silver nitrate, etc. The ruthenium salt can be a nitrosyl nitrate rhenium (III) solution, etc. The palladium salt can be one or a combination of two or more of palladium nitrate, palladium acetate, palladium chloride, etc.

[0092] The present invention does not particularly limit the solvent used to dissolve the active ingredient precursor, and it can be a commonly used solvent in the art, such as water.

[0093] The present invention does not particularly limit the concentration of the active ingredient precursor solution, which can generally be 0.01 to 0.12 mol / L, for example, 0.02 mol / L, 0.04 mol / L, 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, etc.

[0094] Next, the first calcined product is impregnated in an active ingredient precursor solution to obtain a second impregnated product. Similarly, for impregnation, the present invention preferably uses the above-mentioned equal volume impregnation method.

[0095] In the present invention, the immersion time of the first calcined product in the active ingredient precursor solution is not particularly limited, as long as equal volume immersion is achieved. Generally speaking, the immersion time in the additive precursor solution can be 3-5 hours, for example: 3.2 hours, 3.5 hours, 3.8 hours, 4 hours, 4.2 hours, 4.5 hours, 4.8 hours, etc.

[0096] Further, the second impregnation product is subjected to a secondary drying treatment to obtain a second dried product; the solvent physically adsorbed on the surface can be removed by the drying treatment. Specifically, in the present invention, the temperature of the secondary drying treatment is 50-90°C, for example: 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, etc.; the time of the secondary drying treatment is 3-9h, for example: 4h, 5h, 6h, 7h, 8h, etc.

[0097] Furthermore, the second dried product is subjected to a secondary calcination treatment to obtain a CO oxidation catalyst. Through the calcination treatment, the active component can be uniformly loaded on the surface and / or inside of the carrier in the form of oxides.

[0098] Specifically, the temperature of the secondary calcination treatment is 500-700°C, for example: 550°C, 600°C, 650°C, etc.; the time of the secondary calcination treatment is 1-3h, for example: 1.5h, 2h, 2.5h, etc. Preferably, the secondary calcination treatment can be carried out in an air atmosphere. Specifically, the secondary calcination treatment includes heating to 500-700°C and calcining for 1-3h at a heating rate of 1-20°C / min.

[0099] <Third Aspect>

[0100] The third aspect of the present invention provides a use of the CO oxidation catalyst according to the first aspect of the present invention in the catalytic combustion of CO, preferably in the catalytic combustion of CO in steel sintering flue gas.

[0101] Example

[0102] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0103] Example 1

[0104] (1) Weigh 5.8 g of sodium nitrate and 6.03 g of ammonium metavanadate and dissolve them in 80 mL of water, stirring to form a first impregnation solution. Then, 100 g of the cerium oxide support is placed in the first impregnation solution and stirred continuously for 2 hours to obtain a wet cerium oxide support loaded with non-precious metal salts, i.e., a first impregnation product.

[0105] (2) The first impregnation product obtained in step (1) is dried at 60° C. for 7 hours to obtain a cerium oxide dry carrier loaded with a non-precious metal salt, i.e., a first dried product. The non-precious metal first dried product is then heated to 600° C. at a heating rate of 2° C. / min and calcined for 2 hours to obtain a cerium oxide carrier loaded with a non-precious metal, i.e., a first calcined product, wherein, based on the total mass of the carrier as 100%, the metal sodium content is 1.5wt% and the metal vanadium content is 2.5wt%.

[0106] (3) Weigh 5.6 g of platinum nitrate solution, wherein the platinum content of the platinum nitrate solution is 18.09 wt %, dissolve in 80 mL of water, and stir to form a second impregnation solution. Then, 100 g of the first calcined product obtained in step (2) is placed in the second impregnation solution and continuously stirred for 4 h to achieve equal volume impregnation, to obtain a catalyst wet precursor loaded with precious metal salt, i.e., the second impregnation product.

[0107] (4) The second impregnation product obtained in step (3) is dried at 60° C. for 7 h to obtain a catalyst dry precursor loaded with a noble metal salt, i.e., a second dried product. The second dried product is heated to 550° C. at a heating rate of 2° C. / min and calcined for 2 h to obtain a CO oxidation catalyst, wherein the metal platinum content is 1 wt % based on the total mass of the first calcined product as 100%.

[0108] Example 2

[0109] (1) 19.42 g of magnesium nitrate and 4.9 g of ammonium metavanadate were weighed and dissolved in 80 mL of water, and stirred to form a first impregnation solution. Subsequently, 100 g of the cerium oxide support was placed in the first impregnation solution and continuously stirred for 2 h to achieve equal volume impregnation, thereby obtaining a wet cerium oxide support loaded with a non-precious metal salt, i.e., a first impregnation product.

[0110] (2) The first impregnation product obtained in step (1) is dried at 70° C. for 7 hours to obtain a cerium oxide dry carrier loaded with a non-precious metal salt, i.e., a first dried product. The first dried product is then heated to 650° C. at a heating rate of 5° C. / min and calcined for 1.5 hours to obtain a cerium oxide carrier loaded with a non-precious metal, i.e., a first calcined product, wherein, based on the total mass of the carrier being 100%, the metal magnesium content is 3wt% and the metal vanadium content is 2wt%.

[0111] (3) Weigh 5.6 g of platinum nitrate solution, wherein the platinum content of the platinum nitrate solution is 18.09 wt %, and dissolve it in 80 mL of water, stirring to form a second impregnation solution. Then, 100 g of the first calcined product obtained in step (2) is placed in the second impregnation solution and continuously stirred for 4 hours to achieve equal volume impregnation, to obtain a catalyst wet precursor loaded with precious metal salt, i.e., the second impregnation product.

[0112] (4) The second impregnation product obtained in step (3) is dried at 60° C. for 6.5 hours to obtain a catalyst dry precursor loaded with a noble metal salt, i.e., a second dried product. The second dried product is heated to 600° C. at a heating rate of 5° C. / min and calcined for 2 hours to obtain a CO oxidation catalyst, wherein the metal platinum content is 1 wt% based on the total mass of the first calcined product as 100%.

[0113] Example 3

[0114] (1) 9.8 g of magnesium nitrate, 7.91 g of sodium nitrate, 2.46 g of ammonium metavanadate, and 2.05 g of ammonium metatungstate were weighed and dissolved in 80 mL of water, and stirred to form a first impregnation solution. Subsequently, 100 g of the cerium oxide support was placed in the first impregnation solution and continuously stirred for 2 h to achieve equal volume impregnation, thereby obtaining a cerium oxide wet support loaded with a non-precious metal salt, i.e., a first impregnation product.

[0115] (2) The first impregnation product obtained in step (1) is dried at 65° C. for 9 hours to obtain a cerium oxide dry carrier loaded with a non-precious metal salt, i.e., a first dried product. The first dried product is then heated to 650° C. at a heating rate of 2° C. / min and calcined for 2 hours to obtain a cerium oxide carrier loaded with a non-precious metal, i.e., a first calcined product, wherein, based on the total mass of the carrier as 100%, the metal magnesium content is 1.5wt%, the metal sodium content is 2wt%, the metal vanadium content is 1wt%, and the metal tungsten content is 1.5wt%.

[0116] (3) Weigh 5.6 g of platinum nitrate solution, wherein the platinum content of the platinum nitrate solution is 18.09 wt %, and dissolve it in 80 mL of water, stirring to form a second impregnation solution. Then, 100 g of the first calcined product obtained in step (2) is placed in the second impregnation solution and continuously stirred for 4 hours to achieve equal volume impregnation, to obtain a catalyst wet precursor loaded with precious metal salt, i.e., the second impregnation product.

[0117] (4) The second impregnation product obtained in step (3) is dried at 65° C. for 6 h to obtain a catalyst dry precursor loaded with a noble metal salt, i.e., a second dried product. The second dried product is heated to 550° C. at a heating rate of 2° C. / min and calcined for 3 h to obtain a CO oxidation catalyst, wherein the metal platinum content is 1 wt % based on the total mass of the first calcined product as 100%.

[0118] Comparative Example 1

[0119] (1) 5.6 g of platinum nitrate solution, wherein the platinum content of the platinum nitrate solution is 18.09 wt %, is weighed and dissolved in a certain amount of 80 mL of water, and an impregnation solution is formed during stirring. Subsequently, a certain amount of 100 g of cerium oxide support is placed in the impregnation solution and continuously stirred for 4 hours to achieve equal volume impregnation, thereby obtaining a cerium oxide wet support loaded with precious metal salt, i.e., an impregnation product.

[0120] (2) The impregnation product obtained in step (1) is dried at 80° C. for 9 hours to obtain a cerium oxide dry carrier loaded with a noble metal salt, i.e., a dried product. The dried product is then heated to 600° C. at a heating rate of 2° C. / min and calcined for 3 hours to obtain a Pt / CeO2 catalytic combustion catalyst, wherein the metal platinum content is 1.5 wt% based on the total mass of the carrier as 100%.

[0121] Comparative Example 2

[0122] (1) 5.6 g of platinum nitrate solution, wherein the platinum content of the platinum nitrate solution is 18.09 wt %, is weighed and dissolved in 80 mL of water, and an impregnation solution is formed during stirring. Subsequently, 100 g of an alumina carrier (γ-Al2O3) is placed in the impregnation solution and continuously stirred for 4 h to achieve equal volume impregnation, thereby obtaining an alumina wet carrier loaded with precious metal salts, i.e., an impregnation product.

[0123] (2) The impregnation product obtained in step (1) is dried at 80° C. for 9 hours to obtain an alumina dry carrier loaded with a noble metal salt, i.e., a dried product. The dried product is then heated to 600° C. at a heating rate of 2° C. / min and calcined for 3 hours to obtain a Pt / γ-Al2O3 catalytic combustion catalyst, wherein the content of metal platinum is 1.5 wt% based on the total mass of the carrier as 100%.

[0124] Performance Testing

[0125] 1. XRD test

[0126] The CO oxidation catalysts of Examples 1-3 and the conventional industrial catalytic combustion catalysts of Comparative Examples 1-2 were used to analyze the CO oxidation catalysts of Examples 1-3 and 1-2 using a powder X-ray diffraction method using CuK α The radiation experimental conditions were analyzed and the results were as follows Figure 1 shown.

[0127] Figure 1 1-3 are XRD diagrams of the CO oxidation catalysts of Examples 1-3 of the present invention and the conventional industrial catalytic combustion catalysts of Comparative Examples 1-2. Figure 1It can be seen that in the XRD spectra of each catalyst, only the characteristic diffraction peaks of the carrier cerium oxide and aluminum oxide are present, and the noble metal active component and the auxiliary component on the CO oxidation catalyst of the present invention have good dispersibility.

[0128] 2. Toluene-TPD test

[0129] Under the CO oxidation condition of steel sintering flue gas, VOCs are not easily catalytically burned, and eventually adsorbed on the catalyst to cause catalyst carbon deposition and deactivation. The ability of the catalyst to adsorb VOCs determines the amount of carbon deposition and the degree of carbon deposition deactivation. Toluene is the most difficult component of VOCs in steel sintering flue gas to be catalytically burned and the most easily adsorbed on the catalyst surface to form carbon deposition. Therefore, toluene is selected to examine the ability of each catalyst to adsorb VOCs.

[0130] The CO oxidation catalyst of Example 1-3 and the conventional industrial catalytic combustion catalyst of Comparative Example 1-2 (0.1 g) were treated at 300°C for 1 h under 100 ml / min nitrogen (temperature program from 30°C for 30 min to 300°C), and treated at 50°C for 1 h under a mixed gas of toluene and N2 (1000 ppm toluene, nitrogen as the balance gas, temperature program from 30°C for 10 min to 50°C), with a gas flow rate of 100 ml / min. Then, pure N2 with the same flow rate was replaced and maintained for 1 h to discharge the weakly adsorbed toluene. Under N2 atmosphere, the temperature program was increased from 50°C to 500°C, with a heating rate of 10°C / min.

[0131] Figure 2 1-3 are the toluene-TPD diagrams of the CO oxidation catalysts of Examples 1-3 of the present invention and the conventional industrial catalytic combustion catalysts of Comparative Examples 1-2. Figure 2 It can be seen that the CO oxidation catalyst of the present invention hardly adsorbs VOCs, and the conventional industrial catalytic combustion catalysts of Examples 1-2 have a strong ability to adsorb VOCs. The present invention successfully obtains a highly selective and carbon-resistant CO oxidation catalyst that does not adsorb VOCs.

[0132] 3. Experiment on CO catalytic combustion in steel sintering flue gas atmosphere

[0133] 0.1 g of the CO oxidation catalysts of Examples 1-3 and the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2 were respectively tested. Specifically, the CO oxidation catalysts of Examples 1-3 and the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2 were respectively placed in a fixed bed reactor, the reaction gas was a simulated gas of steel sintering flue gas, and the mass space velocity was 60000 mL / (g·h). The CO conversion rate and NO conversion rate of the catalysts at different reaction temperatures in the steel sintering flue gas atmosphere were tested, wherein the CO conversion rate is the conversion rate of CO being oxidized to CO2, and the NO conversion rate is the conversion rate of NO being oxidized to NO2. The results are as follows: Figure 3 and Figure 4 As shown, the simulated gas components of steel sintering flue gas are shown in Table 1.

[0134] Table 1

[0135] Components Carbon monoxide Nitric Oxide Nitrogen dioxide oxygen concentration 10000ppm 275ppm 30ppm 15％

[0136] Depend on Figure 3 It can be seen that the CO oxidation catalyst of the present invention catalyzes the combustion of CO in the steel sintering flue gas atmosphere. 90％ The T values ​​of the conventional industrial catalytic combustion catalysts in Comparative Examples 1 and 2 for catalytic combustion of CO in the atmosphere of steel sintering flue gas are all below 205°C. 90％ About 265°C and 240°C respectively.

[0137] Depend on Figure 4 It can be seen that the CO oxidation catalyst of the present invention hardly oxidizes NO when catalytically combusting CO in the atmosphere of steel sintering flue gas, while the conventional industrial catalytic combustion catalysts of Comparative Examples 1 and 2 oxidize a large amount of NO when catalytically combusting CO in the atmosphere of steel sintering flue gas.

[0138] And from Figure 2 , 3 and Figure 4 It can be seen that the CO oxidation catalyst of the present invention is superior to conventional industrial catalytic combustion catalysts in terms of catalytic combustion of CO, non-oxidation of NO and anti-carbon deposition in the atmosphere of steel sintering flue gas. The preparation method of the present invention is simple and easy to operate.

[0139] 4. Specific surface area and pore volume test

[0140] The specific surface area and pore volume of the CO oxidation catalysts of Examples 1-3 and the conventional industrial catalytic combustion catalysts of Comparative Examples 1-2 were tested using a physical adsorption instrument (Michiko Baier, Japan). The specific surface area was calculated by the Brunauer-Emmett-Teller (BET) method, and the pore volume was calculated by the non-local density functional theory (NLDFT) method. The results are shown in Table 2.

[0141] Table 2

[0142] CO oxidation catalyst <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Example 1 30.1 0.14 Example 2 46.7 0.17 Example 3 32.1 0.15 Comparative Example 1 65.6 0.21 Comparative Example 2 153.3 0.25

[0143] It can be seen from Table 2 that the presence of the additive will reduce the specific surface area and pore volume of the CO oxidation catalyst to a certain extent. Even if the specific surface area and pore volume are reduced, the catalyst of the present application still has a better catalytic combustion CO performance.

[0144] 5. Transmission electron microscopy (TEM) test

[0145] Figure 5 The transmission electron microscope (TEM) image of the CO oxidation catalyst of Example 1 of the present invention is shown. Figure 5 It can be seen that the active ingredients and the auxiliary agents are highly dispersed on the surface of the catalyst support, and no large-sized nanoparticles of the active components or auxiliary components are observed.

[0146] Industrial Applicability

[0147] The CO oxidation catalyst provided by the present invention can be industrially prepared and applied to the catalytic combustion of CO in steel sintering flue gas.

[0148] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0149] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A CO oxidation catalyst, characterized in that It comprises a carrier, an active ingredient and an auxiliary agent loaded on the surface and / or inside of the carrier; wherein, The active ingredient includes a noble metal element, and the auxiliary agent includes a non-noble metal element; Based on the total mass of the carrier as 100%, the content of the auxiliary agent is less than 10%, preferably 3-6%; Based on the total mass of the carrier and the auxiliary agent being 100%, the content of the active ingredient is less than 1.5%, preferably 0.5-1.5%.

2. The CO oxidation catalyst according to claim 1, characterized in that The noble metal element comprises platinum and / or palladium; and / or, The support includes a cerium oxide support and / or an aluminum oxide support.

3. The CO oxidation catalyst according to claim 1 or 2, characterized in that The auxiliary agent includes a first non-precious metal element and a second non-precious metal element. Preferably, the mass ratio of the first non-precious metal element to the second non-precious metal element is 0.2-3:

1.

4. The CO oxidation catalyst according to claim 3, characterized in that The first non-precious metal element includes magnesium and / or sodium, and the second non-precious metal element includes one or a combination of two or more of vanadium, tungsten and molybdenum.

5. The CO oxidation catalyst according to any one of claims 1 to 4, characterized in that: The specific surface area of ​​the CO oxidation catalyst is 25 m 2 / g or more, pore volume is 0.1cm 3 / g or above.

6. A method for preparing a CO oxidation catalyst according to any one of claims 1 to 5, characterized in that: The following steps are involved: dissolving an auxiliary agent precursor in a solvent to obtain an auxiliary agent precursor solution; impregnating the support once in the auxiliary agent precursor solution to obtain a first impregnation product; performing a drying process on the first impregnation product to obtain a first dried product; calcining the first dried product to obtain a first calcined product; dissolving an active ingredient precursor in a solvent to obtain an active ingredient precursor solution; impregnating the first calcined product in an active ingredient precursor solution for a second time to obtain a second impregnated product; performing secondary drying on the second impregnation product to obtain a second dried product; The second dried product is subjected to a secondary calcination treatment to obtain a CO oxidation catalyst.

7. The preparation method according to claim 6, characterized in that: The auxiliary agent precursor includes one or a combination of two or more of magnesium salt, sodium salt, vanadium salt, tungsten salt and molybdenum salt; the active ingredient precursor includes one or a combination of two or more of platinum salt, rubidium salt, silver salt, ruthenium salt and palladium salt; and / or, The first impregnation and / or the second impregnation are equal volume impregnations.

8. The preparation method according to claim 6 or 7, characterized in that: The temperature of the primary drying process and / or the secondary drying process is 50-90° C., and the time of the primary drying process and / or the secondary drying process is 3-9 hours.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The temperature of the primary calcination treatment and / or the secondary calcination treatment is 500-700° C., and the time of the primary calcination treatment and / or the secondary calcination treatment is 1-3 hours; preferably, the primary calcination treatment and / or the secondary calcination treatment is carried out in an air atmosphere.

10. Use of the CO oxidation catalyst according to any one of claims 1 to 5 in catalytic combustion of CO, preferably in catalytic combustion of CO from steel sintering flue gas.

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