阅读说明：本技术 一种稀土溶剂萃取挥发废气专用催化剂及其制备方法与应用 (Special catalyst for extracting volatile waste gas by rare earth solvent and preparation method and application thereof ) 是由 史娟华 崔振 俞小源 孙巧珍 邵明迪 陈璠 高杰 段成林 杨姗姗 于 2020-08-24 设计创作，主要内容包括：本发明提供一种稀土溶剂萃取挥发废气专用催化剂及其制备方法与应用,涉及废气催化燃烧技术领域。本发明提供的稀土溶剂萃取挥发废气专用催化剂包括空白载体,依次涂覆在所述空白载体上的第一涂覆层和第二涂覆层；所述第一涂覆层包括基质、贵金属氧化物和铝氧化物；所述基质为铈锆复合氧化物和改性氧化铝的混合物,所述贵金属氧化物为铂氧化物和/或钯氧化物；所述第二涂覆层包括ZSM-5分子筛、铈氧化物、锰氧化物、铜氧化物和铝氧化物。本发明提供的稀土溶剂萃取挥发废气专用催化剂采用不同基质分层涂覆,不同气体组分在不同基质上进行反应,更有效的保护第一涂覆层中贵金属的催化活性,提高了稀土溶剂萃取挥发废气专用催化剂的催化反应效率。(The invention provides a catalyst special for rare earth solvent extraction of volatile waste gas and a preparation method and application thereof, and relates to the technical field of waste gas catalytic combustion. The catalyst special for extracting volatile waste gas by using the rare earth solvent comprises a blank carrier, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are sequentially coated on the blank carrier; the first coating layer includes a substrate, a noble metal oxide, and an aluminum oxide; the substrate is a mixture of cerium-zirconium composite oxide and modified alumina, and the noble metal oxide is platinum oxide and/or palladium oxide; the second coating layer includes a ZSM-5 molecular sieve, cerium oxide, manganese oxide, copper oxide, and aluminum oxide. The catalyst special for extracting volatile waste gas by the rare earth solvent is coated by different substrates in a layered manner, and different gas components react on different substrates, so that the catalytic activity of noble metal in the first coating layer is protected more effectively, and the catalytic reaction efficiency of the catalyst special for extracting volatile waste gas by the rare earth solvent is improved.)

1. The catalyst special for extracting volatile waste gas by using the rare earth solvent is characterized by comprising a blank carrier, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are sequentially coated on the blank carrier; the first coating layer includes a substrate, a noble metal oxide, and an aluminum oxide; the substrate is a mixture of cerium-zirconium composite oxide and modified alumina, and the noble metal oxide is platinum oxide and/or palladium oxide; the second coating layer includes a ZSM-5 molecular sieve, cerium oxide, manganese oxide, copper oxide, and aluminum oxide.

2. The catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1, wherein the molar ratio of the copper oxide, the manganese oxide and the cerium oxide is 1: (1-3): (3-5).

3. The catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1 or 2, wherein the sum of the mass of the copper oxide, the cerium oxide and the manganese oxide is 20-30% of the mass of the ZSM-5 molecular sieve.

4. The catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1, wherein in the second coating layer, the mass ratio of the aluminum oxide to the ZSM-5 molecular sieve is 55: 45.

5. the catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1, wherein the blank carrier is a cordierite honeycomb carrier.

6. The catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1, wherein the mass ratio of the cerium zirconium composite oxide to the modified alumina is 1: (0.5-2).

7. The catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1, wherein the mass ratio of the noble metal oxide to the matrix is 1: (100-160).

8. The catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in claim 1, wherein in the first coating layer, the mass ratio of the aluminum oxide to the matrix is 55: 45.

9. the preparation method of the catalyst special for rare earth solvent extraction volatilization exhaust gas as claimed in any one of claims 1 to 8, which comprises the following steps:

mixing water, a substrate, a noble metal salt, acetic acid and a first binder to obtain first coating slurry; the first binder is one or more of alumina sol, alumina gel and silica sol;

mixing water, a ZSM-5 molecular sieve, cerium salt, manganese salt, copper salt, acetic acid and a second binder to obtain second coating slurry; the second binder is one or more of alumina sol, alumina gel and silica sol;

after the first coating slurry is coated on a blank carrier, drying in the shade and drying are sequentially carried out, so as to obtain the catalyst special for extracting volatile waste gas by the pre-rare earth solvent;

and coating the second coating slurry on a catalyst special for extracting volatile waste gas by a pre-rare earth solvent, and then drying in the shade, drying and roasting to obtain the catalyst special for extracting volatile waste gas by the rare earth solvent.

10. The application of the catalyst special for rare earth solvent extraction volatile waste gas in any one of claims 1 to 8 or the catalyst special for rare earth solvent extraction volatile waste gas prepared by the preparation method in catalytic combustion of rare earth solvent extraction volatile waste gas.

Technical Field

The invention relates to the technical field of waste gas catalytic combustion, in particular to a special catalyst for extracting volatile waste gas by a rare earth solvent, and a preparation method and application thereof.

Background

Catalytic combustion is a typical gas-solid catalytic reaction, and the principle is that active oxygen participates in deep oxidation. In the catalytic combustion process, the catalyst has the function of reducing the activation energy of the reaction, simultaneously enriching reactant molecules on the surface of the catalyst and improving the reaction rate. Under the action of catalyst, the organic waste gas can be flameless combusted at lower ignition temperature and is decomposed into CO by oxidation₂And H₂A large amount of heat is released in the process of O.

The existing VOCs catalyst is cheap, but is not resistant to chlorine and is easy to poison. The chlorine-resistant VOCs catalyst is expensive and high in use cost, and a special catalyst for the rare earth solvent volatile waste gas is developed by the company aiming at the rare earth solvent volatile waste gas, and has low cost and certain chlorine resistance.

Disclosure of Invention

In view of the above, the present invention aims to provide a catalyst special for rare earth solvent extraction of volatile exhaust gas, and a preparation method and an application thereof.

The invention provides a catalyst special for extracting volatile waste gas by a rare earth solvent, which comprises a blank carrier, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are sequentially coated on the blank carrier; the first coating layer includes a substrate, a noble metal oxide, and an aluminum oxide; the substrate is a mixture of cerium-zirconium composite oxide and modified alumina, and the noble metal oxide is platinum oxide and/or palladium oxide; the second coating layer comprises ZSM-5 molecular sieve, cerium oxide, manganese oxide, copper oxide and aluminum oxide.

Preferably, the molar ratio of the copper oxide, the manganese oxide and the cerium oxide is 1: (1-3): (3-5).

Preferably, the sum of the mass of the copper oxide, the cerium oxide and the manganese oxide is 20-30% of the mass of the ZSM-5 molecular sieve.

Preferably, in the second coating layer, the mass ratio of the aluminum oxide to the ZSM-5 molecular sieve is 55: 45.

preferably, the blank carrier is a cordierite honeycomb carrier.

Preferably, the mass ratio of the cerium-zirconium composite oxide to the modified alumina is 1: (0.5-2).

Preferably, the mass ratio of the noble metal oxide to the matrix is 1: (100-160).

Preferably, in the first coating layer, the mass ratio of the aluminum oxide to the matrix is 55: 45.

the invention also provides a preparation method of the catalyst special for extracting volatile waste gas by the rare earth solvent, which comprises the following steps:

mixing water, a substrate, a noble metal salt, acetic acid and a first binder to obtain first coating slurry; the first binder is one or more of alumina sol, alumina gel and silica sol;

mixing water, a ZSM-5 molecular sieve, cerium salt, manganese salt, copper salt, acetic acid and a second binder to obtain second coating slurry; the second binder is one or more of alumina sol, alumina gel and silica sol;

after the first coating slurry is coated on a blank carrier, drying in the shade and drying are sequentially carried out, so as to obtain the catalyst special for extracting volatile waste gas by the pre-rare earth solvent;

and coating the second coating slurry on a catalyst special for extracting volatile waste gas by a pre-rare earth solvent, and then drying in the shade, drying and roasting to obtain the catalyst special for extracting volatile waste gas by the rare earth solvent.

The invention also provides the application of the catalyst special for extracting volatile waste gas by the rare earth solvent or the catalyst special for extracting volatile waste gas by the rare earth solvent prepared by the preparation method in the technical scheme in the catalytic combustion of the volatile waste gas by the rare earth solvent.

The invention provides a catalyst special for extracting volatile waste gas by a rare earth solvent, which comprises a blank carrier, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are sequentially coated on the blank carrier; the first coating layer includes a substrate, a noble metal oxide, and an aluminum oxide; the substrate is a mixture of cerium-zirconium composite oxide and modified alumina, and the noble metal oxide is platinum oxide and/or palladium oxide; the second coating layer includes a ZSM-5 molecular sieve, cerium oxide, manganese oxide, copper oxide, and aluminum oxide. The catalyst special for extracting volatile waste gas by the rare earth solvent is coated by different matrixes in a layered mode, the ZSM-5 molecular sieve on the second coating layer provides a rich pore channel structure, water and chlorine-containing gas in waste gas components are preferentially adsorbed in pore channels of the catalyst, the chlorine poisoning of noble metal oxide in the first coating layer is avoided, and the service life of the catalyst is prolonged. Oxygen-containing hydrocarbons such as esters, ethers and ketones in the volatile exhaust gas components extracted by the rare earth solvent are preferentially combusted in the pore channels of the second coating layer ZSM-5 under the catalysis of active components (cerium oxide, manganese oxide and copper oxide); and the gas component of benzene alkane which is difficult to catalyze and oxidize is further catalyzed and combusted in the first coating layer, the cerium-zirconium composite oxide is a high-performance oxygen storage material, sufficient oxygen is provided for catalytic combustion in pore channels of the cerium-zirconium composite oxide due to the special property of the cerium-zirconium composite oxide, and the precious metal oxide is a catalytic medium to reduce the activation energy of the combustion reaction of the waste gas component. The catalyst provided by the invention can enable different gas components in the rare earth solvent extraction volatile waste gas to react on different substrates, and the catalytic reaction efficiency of the special catalyst for the rare earth solvent extraction volatile waste gas is improved. The data of the examples show that: compared with the common catalyst, the special catalyst for extracting volatile waste gas by the rare earth solvent has the following advantages: the ignition temperature is about 20 ℃ lower, and the complete catalytic combustion temperature is about 15 ℃ lower, which shows that the special catalyst for extracting volatile waste gas from rare earth solvent provided by the invention utilizes the catalytic activity of noble metal oxide more effectively by layer coating when the temperature is lower.

Drawings

Fig. 1 shows a catalytic combustion activity evaluation device of the present invention.

Detailed Description

The invention provides a catalyst special for extracting volatile waste gas by a rare earth solvent, which comprises a blank carrier, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are sequentially coated on the blank carrier; the first coating layer includes a substrate, a noble metal oxide, and an aluminum oxide; the substrate is a mixture of cerium-zirconium composite oxide and modified alumina, and the noble metal oxide is platinum oxide and/or palladium oxide; the second coating layer includes a ZSM-5 molecular sieve, cerium oxide, manganese oxide, copper oxide, and aluminum oxide.

The catalyst special for extracting volatile waste gas by using the rare earth solvent comprises a blank carrier, wherein the blank carrier is preferably a cordierite honeycomb carrier; the volume of the cordierite honeycomb carrier is preferably 100mm multiplied by 50mm, and the weight is preferably 250-310 g.

The catalyst special for extracting volatile exhaust gas by using the rare earth solvent comprises a first coating layer coated on the blank carrier, wherein the first coating layer comprises a substrate, a noble metal oxide and an aluminum oxide. In the present invention, the substrate is a mixture of a cerium-zirconium composite oxide and a modified alumina; in the mixture, the mass ratio of the cerium-zirconium composite oxide to the modified alumina is preferably 1: (0.5-2), more preferably 1:1, the mass ratio of cerium oxide to zirconium oxide in the cerium-zirconium composite oxide is preferably 40: 50; the modified alumina is preferably lanthanum acetate modified alumina, and more preferably modified alumina of model 3020 purchased from Weifang Zhengxuan rare earth catalytic materials Co. In the present invention, the noble metal oxide is a platinum oxide and/or a palladium oxide, and when the noble metal oxide is a mixture of a platinum oxide and a palladium oxide, the mass ratio of the platinum oxide to the palladium oxide is preferably 1: 1. in the present invention, the mass ratio of the noble metal oxide to the matrix is preferably 1: (100 to 160), and more preferably 1: 120. in the present invention, the mass ratio of the aluminum oxide to the substrate is preferably 55: 45. in the invention, the thickness of the first coating layer is preferably 10-20 μm.

The cerium-zirconium composite oxide and the modified alumina are adopted as the matrixes, and the noble metal oxide is taken as the active substance, so that the gas components of benzene alkanes which are difficult to catalyze and oxidize can be catalyzed and combusted; the cerium-zirconium composite oxide is a high-performance oxygen storage material, and provides sufficient oxygen for catalytic combustion in a pore channel of the cerium-zirconium composite oxide due to the special property of the cerium-zirconium composite oxide, and the precious metal oxide is a catalytic medium to reduce the combustion reaction activation energy of waste gas components, so that the catalytic efficiency is improved.

The catalyst special for extracting volatile waste gas by using the rare earth solvent comprises a second coating layer coated on the first coating layer, wherein the second coating layer comprises a ZSM-5 molecular sieve, cerium oxide, manganese oxide, copper oxide and aluminum oxide. In the present invention, the molar ratio of the copper oxide, the manganese oxide and the cerium oxide is preferably 1: (1-3): (3-5), more preferably 1:2: 4. in the present invention, the sum of the mass of the copper oxide, the cerium oxide and the manganese oxide is preferably 20 to 30%, and more preferably 25% of the mass of the ZSM-5 molecular sieve. In the present invention, the mass ratio of the aluminum oxide to the ZSM-5 molecular sieve is preferably 55: 45. in the invention, the thickness of the second coating layer is preferably 10-20 μm.

In the invention, the ZSM-5 molecular sieve in the second coating layer can provide rich pore channel structures, so that the active components can be conveniently attached, and the ZSM-5 molecular sieve has certain adsorption performance, so that the moisture and chlorine-containing gas in the waste gas are adsorbed in the ZSM-5 pore channels, and the phenomenon that the chlorine-containing gas poisons the noble metal oxide in the first coating layer to lose the catalytic activity is effectively prevented. Cerium oxide, manganese oxide and copper oxide can play a role in catalyzing in the combustion process of waste gas, the reaction activation energy is reduced, the use amount of fuel gas is further reduced, the cost is saved, and finally the catalyst has higher catalytic activity and the service life is prolonged.

The catalyst special for extracting volatile waste gas by the rare earth solvent is coated by different substrates in a layered manner, and different gas components react on different substrates, so that the catalytic activity of the noble metal oxide in the first coating layer is protected more effectively, and the catalytic reaction efficiency of the catalyst special for extracting volatile waste gas by the rare earth solvent is improved.

The invention also provides a preparation method of the catalyst special for extracting volatile waste gas by the rare earth solvent, which comprises the following steps:

mixing water, a substrate, a noble metal salt, acetic acid and a first binder to obtain first coating slurry; the first binder is one or more of alumina sol, alumina gel and silica sol;

mixing water, a ZSM-5 molecular sieve, cerium salt, manganese salt, copper salt, acetic acid and a second binder to obtain second coating slurry; the second binder is one or more of alumina sol, alumina gel and silica sol;

after the first coating slurry is coated on a blank carrier, drying in the shade and drying are sequentially carried out, so as to obtain the catalyst special for extracting volatile waste gas by the pre-rare earth solvent;

and coating the second coating slurry on a catalyst special for extracting volatile waste gas by a pre-rare earth solvent, and then drying in the shade, drying and roasting to obtain the catalyst special for extracting volatile waste gas by the rare earth solvent.

According to the invention, water, a substrate, a noble metal salt, acetic acid and a first binder are mixed to obtain a first coating slurry.

In the present invention, the noble metal salt is preferably a noble metal nitrate; the amount of the noble metal salt to be used with the substrate preferably satisfies the relationship between the amount of the noble metal oxide to be used with the substrate in the first coating layer. In the invention, the first binder is preferably one or more of aluminum sol, aluminum glue and silica sol, and is further preferably aluminum glue; the mass ratio of the first binder to the substrate, measured as a mass after burn-off, is preferably 55: 45, the molar ratio of the hydrogen ions in the acetic acid to the aluminum ions in the first binder is preferably 1: 0.2. in the present invention, the solid content of the first coating slurry is preferably 25 to 35%.

In the present invention, the mixing preferably comprises the steps of:

mixing the first part of water and the matrix, performing wet ball milling, mixing the noble metal salt and the second part of water in a sprayer, spraying the mixture into the wet ball milling mixture, and performing wet ball milling to obtain a first feed liquid; and mixing the rest water and acetic acid, performing wet ball milling, adding a first binder, performing wet ball milling, adding the first feed liquid, and performing wet ball milling to obtain first coating slurry.

In the present invention, the wet ball milling is preferably performed in a wet mill.

The parameters of the wet ball milling are not particularly limited in the present invention as long as the particle size of the final first coating slurry satisfies D₅₀< 2.0 μm and D₉₀Less than or equal to 5.0 mu m.

The invention mixes water, ZSM-5 molecular sieve, cerium salt, manganese salt, copper salt, acetic acid and second binder to obtain second coating slurry.

In the present invention, the copper salt is preferably a divalent copper salt, more preferably copper nitrate trihydrate, the manganese salt is preferably a divalent manganese salt, more preferably manganese nitrate, and the cerium salt is preferably a trivalent cerium salt, more preferably cerium nitrate hexahydrate. In the present invention, the molar ratio of the copper salt, the manganese salt and the cerium salt is preferably 1: (1-3): (3-5), more preferably 1:2: 4; the dosage ratio of the copper salt to the ZSM-5 molecular sieve is preferably 2.9 mol: 12 kg. In the invention, the second binder is preferably one or more of aluminum sol, aluminum glue and silica sol, and is further preferably aluminum glue; the molar ratio of hydrogen ions in the acetic acid to aluminum ions in the second binder is preferably 1: 0.2; the mass ratio of the second binder to the ZSM-5 molecular sieve is preferably 55: 45. in the present invention, the solid content of the second coating slurry is preferably 25 to 35%.

In the present invention, the mixing preferably comprises the steps of:

mixing the first part of water and a ZSM-5 molecular sieve, performing wet ball milling, mixing a cerium salt, a manganese salt, a copper salt and the second part of water in a sprayer, spraying the mixture into the mixture after ball milling, and performing wet ball milling to obtain a first feed liquid; and mixing the rest water and acetic acid, performing wet ball milling, adding a second binder, performing ball milling, adding the first feed liquid, and performing wet ball milling to obtain second coating slurry.

In the present invention, the wet ball milling is preferably performed in a wet mill.

The parameters of the wet ball milling are not particularly limited in the present invention as long as the particle size of the final second coating slurry satisfies D₅₀< 2.0 μm and D₉₀Less than or equal to 5.0 mu m.

After the first coating slurry and the second coating slurry are obtained, the first coating slurry is coated on a blank carrier, and then the blank carrier is dried in the shade and dried in sequence to obtain the catalyst special for extracting and volatilizing waste gas by the pre-rare earth solvent.

The method of applying the first coating slurry to the blank support is not particularly limited.

In the invention, when the blank carrier is preferably a cordierite honeycomb carrier with the volume of 100mm multiplied by 50mm, the dosage of the first coating slurry is preferably 80-150 g. In the present invention, the drying time in the shade is preferably 12 hours; the drying temperature is preferably 120 ℃, and the drying time is preferably 4 hours.

After the catalyst special for the pre-rare earth solvent extraction volatilization waste gas is obtained, the second coating slurry is coated on the catalyst special for the pre-rare earth solvent extraction volatilization waste gas, and then the catalyst special for the rare earth solvent extraction volatilization waste gas is obtained through drying in the shade, drying and roasting in sequence.

The method of applying the second coating slurry to the catalyst dedicated for the pre-rare earth solvent extraction of the volatilized exhaust gas is not particularly limited in the present invention.

In the invention, when the blank carrier is preferably a cordierite honeycomb carrier with the volume of 100mm multiplied by 50mm, the dosage of the second coating slurry is preferably 80-120 g. In the present invention, the drying time in the shade is preferably 12 hours; the drying temperature is preferably 90-200 ℃, and further preferably 120-150 ℃; the time is preferably 1 to 6 hours, and more preferably 3 to 4 hours; the roasting temperature is preferably 400-700 ℃, the roasting temperature is further preferably 500-600 ℃, and the roasting time is preferably 4-6 h. In the present invention, the calcination is preferably carried out in a mesh belt kiln.

The preparation method provided by the invention can load the first coating slurry and the second coating slurry on the blank carrier in sequence, so that copper salt, manganese salt and cerium salt in the second coating slurry are converted into cerium oxide, manganese oxide and copper oxide, and meanwhile, noble metal salt in the first coating slurry is converted into noble metal oxide through roasting, so that the copper oxide-manganese oxide-cerium oxide layer and the noble metal oxide layer are arranged in a layered manner and are subjected to catalytic reaction respectively, and the catalytic performance of the catalyst special for extracting volatile waste gas by using a rare earth solvent is improved.

The invention also provides the application of the catalyst special for extracting volatile waste gas by the rare earth solvent or the catalyst special for extracting volatile waste gas by the rare earth solvent, which is obtained by the preparation method in the technical scheme, in the catalytic combustion of the volatile waste gas extracted by the rare earth solvent.

In the invention, the temperature of the catalytic combustion is preferably 300-450 ℃, and more preferably 350 ℃. The dosage of the catalyst special for extracting the volatile waste gas by the rare earth solvent is not particularly limited, and the catalyst can be selected and set by a person skilled in the art according to the actual situation.

The catalyst for extracting volatile exhaust gas from rare earth solvent provided by the present invention, the preparation method and the application thereof are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.