Method for forming a strip-shaped support, method for preparing a metal-loaded catalyst, catalyst and use thereof

Abstract

This invention discloses a method for preparing a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production, comprising a support preparation process and a support impregnation process. The support preparation process includes five units: vigorous mixing of raw materials, compaction into blocks, extrusion molding, drying and curing, and high-temperature calcination. The vigorous mixing of raw materials is performed using a drum-type vigorous mixer with a rotor. The support impregnation process includes five units: drum impregnation, high-temperature drying, high-temperature calcination, rolling pelletizing, and vibrating sieve dust removal. This invention has the advantages of good mixing effect between dry powder and liquid raw materials, low nitrogen oxide emissions, high support strength, and longer catalyst life.

Description

Technical Field

[0001] This invention relates to a method for forming a support, a method for preparing a catalyst, a catalyst and its application, and more specifically, to a method for forming a strip support, a method for preparing a strip-shaped hydrogen peroxide decomposition catalyst loaded with metal, the obtained catalyst and its application in hydrogen peroxide decomposition. Background Technology

[0002] The demand for hydrogen peroxide is increasing significantly across various industries. For example, it is used for bleaching in the paper and textile industries to obtain pulp and fibers with satisfactory and stable whiteness; in the electronics industry, it is used for cleaning silicon wafers and etching circuit boards; in the food industry, it is used for preservation, disinfection, and aseptic packaging; and in the environmental field, it is used to treat wastewater containing organic matter, significantly reducing the chemical oxygen demand (COD) of wastewater to meet wastewater discharge requirements. Hydrogen peroxide has excellent oxidizing properties, and its reduction product is water, which is non-toxic, harmless, and does not introduce impurities into the system. Compared with traditional oxidants, it has significant advantages in environmental friendliness and economy. Especially after the advent and industrial production of titanium-silicon molecular sieve (TS-1), it forms a mild and efficient catalytic oxidation system with hydrogen peroxide, exhibiting good activity and selectivity in the hydroxylation of benzene and phenol, the epoxidation of olefins, the ammonium oximeization of cyclohexanone, and the oxidation of amines and saturated alkanes.

[0003] However, in the above oxidation reaction process, the conversion rate of hydrogen peroxide is usually maintained between 97% and 99%, leaving 0.05% to 0.5% hydrogen peroxide by mass in the reaction products. This portion of hydrogen peroxide can react with organic matter in the subsequent separation process to form easily explosive organic peroxides, or it may decompose itself to release oxygen, affecting the safe and continuous operation of the equipment. Therefore, from a safety perspective, it is necessary to use a hydrogen peroxide decomposition catalyst to catalytically decompose it. The most common hydrogen peroxide decomposition catalysts are metal oxides, among which manganese oxides are the most common. For example, CN110240203A discloses a method for preparing a manganese oxide catalyst. However, metal oxide catalysts need to be loaded into industrial reactors such as fixed beds before use, so such catalysts need to be shaped to meet the loading requirements of fixed beds or other reactors. Currently, there are few reports on the shaping technology of metal oxide catalysts. Although CN114471591A discloses a strip-shaped decomposition catalyst, it does not disclose a specific shaping method. Summary of the Invention

[0004] The inventors discovered that in the diverse catalyst molding processes, the molding steps, molding equipment, and process routes have a significant impact on the strength and catalytic activity of the catalyst. The preparation of molded catalysts that can meet the needs of industrial applications, such as the filling requirements of industrial fixed-bed reactors, remains a challenge.

[0005] The purpose of this invention is to provide a method for preparing a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production. The catalyst prepared by this method has excellent side pressure strength, meets the packing requirements of industrial fixed beds, and when applied to the hydrogen peroxide decomposition reaction, it has a good catalytic decomposition effect on low concentrations of hydrogen peroxide at low reaction temperatures.

[0006] Therefore, the first aspect of the present invention provides a method for preparing a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production, comprising a support preparation process and a support impregnation metal process; characterized in that,

[0007] The carrier preparation process includes five units: vigorous mixing of raw materials, crushing into blocks, extrusion molding, drying and curing, and high-temperature calcination; wherein, the vigorous mixing of raw materials is carried out using a drum-type vigorous mixer with a rotor.

[0008] The carrier impregnation process includes five units: drum impregnation, high-temperature drying, high-temperature calcination, rolling pelletizing, and vibrating sieve powder removal.

[0009] During the carrier preparation process, the high-intensity mixing of the raw materials involves mixing the dry powder materials in a drum-type high-intensity mixer for 20-30 minutes at a rotor speed of 80-120 r / min and a drum rotation speed of 60-100 r / min. In the drum-type high-intensity mixer, the rotor and drum rotate in opposite directions. The dry powder materials include one or more of the following: aluminum hydroxide powder, titanium dioxide powder, soluble starch, and guar gum powder.

[0010] The raw material vigorous mixing unit in the carrier preparation process further includes a step of adding liquid material through a liquid feed hole without changing the stirring speed, followed by vigorous mixing for 45-60 minutes at a rotor speed of 300-400 r / min and a drum rotation speed of 100-150 r / min. The liquid material is a paste-forming agent, dilute nitric acid, with a mass concentration of 2%-5%. The material obtained after the vigorous mixing unit remains a powder and does not clump. The liquid material includes one or more of acidic aluminum sol, alkaline silica sol, alkylphenol polyoxyethylene ether, and dilute nitric acid.

[0011] In the carrier preparation process, the crushing into blocks involves pouring the powder obtained from the raw material strong mixing unit into a crusher for crushing. The preferred ratio of the weight of the crushing wheel to the mass of the powder is 1:1 to 2:1, the preferred crushing speed is 100 to 150 r / min, and the crushing time is 40 to 60 minutes.

[0012] After the rolling and lumping unit of the carrier preparation process is completed, the powder is lumped into blocks, and the size of the blocks is preferably 5 to 15 cm.

[0013] In the carrier preparation process, the extrusion molding involves feeding the block material obtained from the rolling unit into a screw extruder for extrusion molding to obtain a wet long strip material, with an extrusion speed of 2-5 cm / s.

[0014] In the carrier preparation process, the drying and curing process involves drying the wet strip material obtained from the extrusion molding unit in a well-ventilated place to obtain dry strip material. The curing temperature is 20-50℃ and the curing time is 16-24 hours.

[0015] In the carrier preparation process, the high-temperature roasting involves roasting the dried strip material obtained from the drying and curing unit in a continuous mesh belt kiln. The material is stacked to a height of 3–4 cm on the mesh belt, the roasting temperature is 500–700℃, and the roasting time is 5–10 hours, resulting in a strip-shaped carrier. After the high-temperature roasting unit in the carrier preparation process, the average lateral compressive strength of the strip-shaped carrier is 120–180 N / cm.

[0016] During the carrier impregnation process, the drum impregnation involves pouring the strip-shaped carrier into an intermittent drum, and then pouring the impregnation solution of the metal precursor into the drum for carrier impregnation.

[0017] The metal is selected from one or more of the following: chromium, molybdenum, tungsten, copper, gold, silver, manganese, rhenium, zirconium, hafnium, cobalt, rhodium, iridium, gallium, indium, thallium, lanthanum, and cerium.

[0018] The precursor of the metal is one or more of metal nitrates, metal ammonium salts, and metal carboxylates. For example, the precursor of the metal can be one or more of copper nitrate trihydrate, lanthanum nitrate hexahydrate, ammonium tungstate pentahydrate, ammonium molybdate tetrahydrate, chromium nitrate nonahydrate, cobalt nitrate hexahydrate, zirconium oxynitrate dihydrate, manganese nitrate, ammonium chloroaurate trihydrate, silver nitrate, ammonium perrhenate, ammonium tetrabutyl hafnium tetrachlorooxynitrate, rhodium hexanoate, ammonium chloroiridate hexahydrate, gallium nitrate, indium nitrate tetrahydrate, thallium nitrate trihydrate, and cerium nitrate dihydrate.

[0019] The composition of the catalyst involved in this invention can be found in references to CN106140139A, CN106140149A, CN106140178A, CN111774064A, CN114471556A, CN114471591A, CN106140186A, CN106140148A, CN106140191A, CN114478442A, etc.

[0020] The preferred mass ratio of the impregnation solution to the strip carrier is 1:1 to 1.4:1; the preferred impregnation vacuum is 0.06 to 0.10 MPa; the preferred impregnation temperature is 30 to 50°C; the preferred impregnation time is 30 to 50 minutes; and the preferred drum rotation speed is 2 to 4 r / min. After impregnation, while maintaining the drum vacuum and rotation speed, steam is introduced into the drum jacket to completely evaporate the impregnation solution. The evaporation temperature is 90 to 120°C, and the evaporation time is 1 to 2 hours.

[0021] During the carrier impregnation process, the high-temperature drying involves drying the carrier obtained from the drum impregnation unit in a drying oven at a temperature of 100–120°C for 4–6 hours.

[0022] During the carrier impregnation process, the high-temperature calcination involves calcining the carrier obtained from the high-temperature drying unit of the carrier impregnation process in a continuous mesh belt kiln to obtain a strip-shaped catalyst. The carrier is stacked on the mesh belt at a height of 3-4 cm, the calcination temperature is 500-800℃, and the calcination time is 4-8 hours.

[0023] During the carrier impregnation process, the rolling pelletizing involves pelletizing the strip-shaped catalyst obtained from the high-temperature calcination unit of the carrier impregnation process in a rolling pelletizer, with the rolling pelletizer rotating at a speed of 100–200 r / min.

[0024] During the carrier impregnation process, the vibrating screen de-pulverization involves sieving the broken and pulverized catalyst obtained from the rolling pelletizing unit in a vibrating screen to remove it. The aperture size of the vibrating screen is no larger than the diameter of the carrier, the proportion of broken and pulverized catalyst is 2% to 8%, and the average lateral compressive strength of the catalyst is 120 to 180 N / cm.

[0025] A second aspect of this invention provides a method for forming a carrier in industrial production, characterized by comprising five units: vigorous mixing of raw materials, rolling into blocks, extrusion forming, drying and curing, and high-temperature firing; wherein,

[0026] The raw material high-intensity mixing is performed using a drum-type high-intensity mixer with a rotor. The dry powder material is mixed for 20 to 30 minutes in the drum-type high-intensity mixer with a rotor speed of 80 to 120 r / min and a drum rotation speed of 60 to 100 r / min. The rotor and drum rotate in opposite directions. The raw material high-intensity mixing unit also includes a step of adding liquid material through a liquid inlet without changing the mixing speed, and then increasing the rotor speed to 300 to 400 r / min and the drum rotation speed to 100 to 150 r / min, with a high-intensity mixing time of 45 to 60 minutes.

[0027] The crushing and lumping process involves pouring the powder obtained from the raw material strong mixing unit into a crushing machine for crushing. The weight ratio of the crushing wheel to the powder is 1:1 to 2:1, the crushing speed is 100 to 150 r / min, and the crushing time is 40 to 60 minutes. After the crushing and lumping unit is completed, the powder is formed into lumps with a size of 5 to 15 cm.

[0028] The extrusion forming process involves feeding the block material obtained from the rolling unit into a screw extruder for extrusion forming to obtain wet long strip material, with an extrusion speed of 2-5 cm / s.

[0029] The drying and curing process involves drying the wet strip material obtained from the extrusion molding unit in a well-ventilated place to obtain dry strip material. The curing temperature is 20-50℃, and the curing time is 16-24 hours.

[0030] The high-temperature roasting involves roasting the dried strip material obtained from the drying and curing unit in a continuous mesh belt kiln. The material is stacked to a height of 3-4 cm on the mesh belt, the roasting temperature is 500-700℃, and the roasting time is 5-10 hours, resulting in a strip-shaped carrier.

[0031] The third aspect of the present invention provides a hydrogen peroxide decomposition catalyst prepared according to the first aspect of the present invention.

[0032] A fourth aspect of the present invention provides a method for the decomposition of hydrogen peroxide in an aqueous methanol solution, characterized in that it uses the hydrogen peroxide decomposition catalyst provided in the third aspect above.

[0033] The methanol-water solution contains 0.02%–1.0% hydrogen peroxide by mass. The method is carried out in a fixed-bed reactor, with a feed mass hourly space velocity (WHSV) of 1–10 h⁻¹ for the methanol-water solution. -1 The reaction temperature is 20–100°C.

[0034] This invention has the following advantages: It improves the mixing effect of dry powder and liquid raw materials, significantly reduces the amount of dilute nitric acid used in the paste-making process, and reduces nitrogen oxide emissions during roasting. It also improves the kneading effect, resulting in a stronger carrier under the same conditions; the mesh belt kiln roasting allows for continuous production with good ventilation, reducing roasting temperature and time; the impregnation is more uniform, the catalyst deactivation rate is slower, and the catalyst life is longer. Detailed Implementation

[0035] The present invention will be further illustrated by the following examples.

[0036] In all examples and comparative examples, the lateral crushing strength of the catalyst was determined using a ZQJ-Ⅱ intelligent particle strength tester manufactured by Dalian Intelligent Testing Machine Factory, in accordance with the HG / T2782-1996 standard. The measured lateral crushing strength was the average value of 3 to 5 groups of 25 catalyst particles per group.

[0037] Example 1

[0038] This embodiment illustrates the method for molding the carrier provided by the present invention.

[0039] Step 1: Add 900g of aluminum hydroxide (produced by Shandong Zibo Taiguang Chemical Co., Ltd.), 1300g of titanium dioxide powder (produced by Guangdong Guanghua Technology Co., Ltd.), 400g of soluble starch (produced by Guangdong Guanghua Technology Co., Ltd.), and 100g of guar gum powder (produced by Fushun Shengfei Chemical Co., Ltd.) to a rotary drum mixer (produced by Erich Ltd.) with a rotor. The rotor speed inside the drum is 100r / min, the drum speed is 80r / min, and the high-intensity mixing time is 30 minutes. The rotor and drum rotate in opposite directions to perform high-intensity mixing of the dry powder materials. After the dry powder materials are mixed evenly, the rotation speed is kept constant. Liquid materials are added through the liquid feed hole in the following order: 1800g of acidic aluminum sol (produced by Hunan Jianchang Petrochemical Co., Ltd.), 150g of octylphenol polyoxyethylene ether-15 (produced by Guangdong Guanghua Technology Co., Ltd.), and 500g of dilute nitric acid (paste preparation, mass fraction 2%). Then, the rotor speed inside the drum is increased to 350r / min, and the drum rotation speed is increased to 120r / min. The intense mixing time is 60 minutes. The rotor and drum rotate in opposite directions to carry out intense mixing of dry powder materials and liquid materials. The final product is still powder, and no material agglomeration is observed.

[0040] Step 2: Spread the strongly mixed material evenly in the rolling mill. The rolling mill wheel weighs 10kg, the rolling speed is 120r / min, and the rolling time is 60 minutes. After rolling, the powder will clump together into blocks, with the maximum size not exceeding 15cm.

[0041] Step 3: Feed the crushed block material into a screw extruder for extrusion forming. The extrusion diameter is 2.2mm and the extrusion speed is 4cm / s.

[0042] Step 4: Dry and cure the wet strip material obtained by extrusion in a well-ventilated place at a temperature of 30℃ for 18 hours. After curing, a hard strip material is obtained.

[0043] Step 5: The dried strip material obtained from the curing process is subjected to high-temperature roasting in a continuous mesh belt kiln. The material is stacked to a height of 4 cm on the mesh belt, the roasting temperature is 600℃, and the roasting time is 6 hours to obtain a strip carrier. The average lateral compressive strength of the strip carrier is 125 N / cm.

[0044] Example 2

[0045] This embodiment illustrates the preparation method of the strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst provided by the present invention.

[0046] Step 1: Pour 2500g of the strip-shaped carrier prepared in Example 1 into an intermittent rotary drum. Then prepare 1500g of ammonium molybdate tetrahydrate aqueous solution (300g of ammonium molybdate tetrahydrate) and 1500g of copper nitrate trihydrate aqueous solution (300g of copper nitrate trihydrate). Pour the two impregnation solutions into the rotary drum separately. The impregnation vacuum is 0.08MPa, the impregnation temperature is 30℃, the impregnation time is 40 minutes, and the drum rotation speed is 4r / min. After impregnation, maintain the drum vacuum and rotation speed unchanged, and then introduce steam into the drum jacket to completely evaporate the impregnation solution. The evaporation temperature is 100℃, and the evaporation time is 2 hours. At this time, the carrier obtained is a uniform blue color.

[0047] Step 2: Dry the obtained carrier in a drying oven at 100℃ for 6 hours.

[0048] Step 3: The obtained carrier is calcined at high temperature in a continuous mesh belt kiln. The carrier is stacked to a height of 3 cm on the mesh belt, the calcination temperature is 800℃, and the calcination time is 5 hours to obtain a strip-shaped catalyst with a yellowish-brown surface and a light blue core.

[0049] Step 4: The obtained strip catalyst is granulated in a granulator at a rotation speed of 120 r / min.

[0050] Step 5: The granulated catalyst is screened in a vibrating screen to remove broken and pulverized catalyst. The screen size of the vibrating screen is 1.6 mm, the proportion of broken and pulverized catalyst is 5%, and the average lateral pressure strength of the catalyst is 128 N / cm.

[0051] Example 3

[0052] This embodiment illustrates the decomposition reaction method of hydrogen peroxide in methanol aqueous solution provided by the present invention.

[0053] The catalyst obtained in Example 2 was loaded into a fixed-bed reactor to decompose hydrogen peroxide in a methanol-water solution. The mass fraction of methanol was 48%, the mass fraction of hydrogen peroxide was 0.5%, and the feed mass hourly space velocity (MHSV) of the methanol-water solution was 8 h⁻¹. -1The reaction temperature was 65℃. The hydrogen peroxide concentration at the outlet of the fixed-bed reactor was analyzed using a hydrogen peroxide titrator (Metroën, Switzerland). The reaction time corresponding to an outlet hydrogen peroxide concentration exceeding 0.02% was defined as the catalyst's lifespan, which was 280 hours.

[0054] Comparative Example 1

[0055] This comparative example illustrates the molding of the comparison carrier.

[0056] The operation was carried out according to steps 1 to 5 in Example 1, except that no strong mixing was performed in step 1. Instead, a multi-functional catalyst forming machine (produced by South China University of Technology Science and Technology Industrial Plant) was used to mix the dry powder and wet powder materials. The hopper of the forming machine was fixed, the maximum speed of the internal blades was 60 r / min, the amount of dilute nitric acid (mass fraction 2%) added was 850 g, and the average lateral compressive strength of the resulting strip carrier was 120 N / cm.

[0057] Comparative Example 2

[0058] This comparative example illustrates the molding of the comparison carrier.

[0059] The operation was carried out according to steps 1 to 5 in Example 1, except that a rolling mill was not used in step 2. Instead, a multi-functional catalyst forming machine (produced by South China University of Technology Science and Technology Industrial Plant) was used to knead the powder into blocks. The maximum kneading speed of the paddle was 60 r / min, and the amount of dilute nitric acid (mass fraction 2%) added was 850 g. The average lateral compressive strength of the resulting strip carrier was 100 N / cm.

[0060] Comparative Example 3

[0061] This comparative example illustrates the molding of the comparison carrier.

[0062] The operation was carried out according to steps 1 to 5 in Example 1, except that the rolling and lumping step in step 2 was omitted, and the powder after strong mixing was directly extruded in the extruder in step 3. The average lateral compressive strength of the resulting strip carrier was 75 N / cm.

[0063] Comparative Example 4

[0064] This comparative example illustrates the molding of the comparison carrier.

[0065] The operation was carried out according to steps 1 to 5 in Example 1, except that step 4, drying and curing, was omitted, and the wet strip material was directly roasted at high temperature. The average strength of the resulting strip carrier was 60 N / cm.

[0066] Comparative Example 5

[0067] This comparative example illustrates the molding of the comparison carrier.

[0068] The operation was carried out according to steps 1 to 5 in Example 1, except that the high-temperature calcination device in step 5 was replaced with a muffle furnace, and the average strength of the resulting strip carrier was 80 N / cm.

[0069] Comparative Example 6

[0070] This comparative example illustrates the molding of the comparison carrier.

[0071] The operation was carried out according to steps 1 to 5 in Example 1, except that the high-temperature calcination device in step 5 was replaced with a muffle furnace, and the calcination temperature was increased to 700°C and the calcination time was extended to 12 hours. The average strength of the resulting strip carrier was 122 N / cm.

[0072] Comparative Example 7

[0073] This comparative example illustrates the preparation of the comparative catalyst.

[0074] The operation was carried out according to steps 1 to 5 of Example 2, except that the drum impregnation in step 1 was replaced with static immersion impregnation, that is, after the carrier and impregnation solution were mixed, they were left to stand under normal pressure for 12 hours. After the impregnation solution was evaporated, the carrier was blue but the color varied in intensity. After calcination, the lighter impregnation areas were light blue, and the darker impregnation areas were yellow.

[0075] Comparative Example 8

[0076] This comparative example illustrates the preparation of the comparative catalyst.

[0077] The operation is carried out according to steps 1 to 5 of Example 2, except that the high-temperature roasting device in step 3 is replaced with a muffle furnace and the roasting time is extended to 12 hours.

[0078] Comparative Example 9

[0079] This embodiment illustrates a method for the decomposition of hydrogen peroxide in an aqueous methanol solution using a comparative catalyst.

[0080] The lifetime of the comparative catalyst of Comparative Example 7 was evaluated according to Example 3. The lifetime of the comparative catalyst was 200 hours.

[0081] A comparison of the carrier molding process in Example 1 with that in Comparative Example 1 shows that when using a traditional molding machine or kneader to mix and stir materials, the mixing rate is too low, making it impossible to achieve strong mixing of dry powder and liquid materials. As a result, it is more difficult for water molecules in the liquid material to enter the dry powder material. Therefore, more dilute nitric acid (2% by mass) needs to be added to knead the mixture into agglomerates, which leads to the emission of more nitrogen oxides during the carrier calcination process.

[0082] Comparing the molding process of the carrier in Example 1 with that of the comparative carrier obtained in Comparative Example 2, it can be seen that when using a traditional molding machine or kneader to knead materials into blocks, due to the low kneading speed, more dilute nitric acid (2% by mass) is needed to knead into agglomerates, resulting in the emission of more nitrogen oxides during the carrier calcination process. Furthermore, the kneading effect of the rolling mill is better, resulting in a carrier with higher strength.

[0083] Comparing the carrier molding process in Example 1 with the comparative carrier molding process obtained in Comparative Example 3, it can be seen that the powder after strong mixing of dry powder and liquid material can also be directly extruded, but the strength of the resulting carrier is very low. This indicates that the powder after strong mixing must be kneaded to improve the carrier strength.

[0084] Comparing the carrier molding process in Example 1 with that in Comparative Example 4, it can be seen that the wet elongated material after extrusion has a high moisture content. Direct high-temperature calcination causes rapid moisture evaporation, resulting in a loose carrier with very low strength, which cannot meet the strength requirements for industrial fixed-bed packing. This demonstrates that drying and curing are essential steps in this invention.

[0085] Comparing the molding process of the carrier in Example 1 with the molding process of the comparative carriers obtained in Comparative Examples 5-6, it can be seen that since the carrier raw material contains more organic matter, after replacing the well-ventilated mesh belt kiln with a sealed muffle furnace, a higher baking temperature and a longer baking time are required to achieve the same carrier strength, resulting in higher energy consumption during the baking process.

[0086] Comparing the process of obtaining the catalyst by impregnating the support with metal in Example 2 with the impregnation process of the comparative catalyst obtained in Comparative Example 7, it can be seen that after the support impregnation process is changed from dynamic impregnation in a rotating drum under vacuum to static impregnation under normal pressure, the impregnation time is extended and the degree of impregnation is uneven, resulting in different colors of the metal oxides on the support surface after calcination under the same conditions.

[0087] Comparing the catalyst impregnation process of the carrier in Example 2 with the impregnation process of the comparative catalyst obtained in Comparative Example 8, it can be seen that after replacing the roasting equipment from a well-ventilated mesh belt kiln to a sealed muffle furnace, a longer roasting time is required to achieve the same roasting effect, resulting in higher energy consumption during the roasting process.

[0088] A comparison of the results of the decomposition reaction of hydrogen peroxide in methanol aqueous solution in Example 3 and Comparative Example 9 shows that, due to the uneven impregnation degree, the active metal oxide species on the surface of the catalyst obtained by static impregnation will aggregate, and the aggregated metal oxide species will be lost faster. Therefore, the catalyst prepared by Comparative Example 7 in Comparative Example 9 has a shorter service life.

[0089] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0091] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production, comprising a support preparation process and a support impregnation process; characterized in that, The carrier preparation process includes five units: vigorous mixing of raw materials, compaction into blocks, extrusion molding, drying and curing, and high-temperature calcination; among which... The high-intensity mixing of the raw materials is performed using a drum-type high-intensity mixer with a rotor. The dry powder material is subjected to high-intensity mixing for 20-30 minutes at a rotor speed of 80-120 r / min and a drum rotation speed of 60-100 r / min. Following this, liquid material is added through a liquid inlet without changing the mixing speed. Then, the rotor speed is increased to 300-400 r / min and the drum rotation speed is increased to 100-150 r / min, with a high-intensity mixing time of 45-60 minutes. In the drum-type high-intensity mixer, the rotor and drum rotate in opposite directions. The dry powder material includes aluminum hydroxide powder, titanium dioxide powder, soluble starch, and guar gum powder. The liquid material includes acidic aluminum sol, alkaline silica sol, alkylphenol polyoxyethylene ether, and dilute nitric acid. The crushing into blocks involves pouring the powder obtained from the raw material strong mixing unit into a crushing machine for crushing. The weight ratio of the crushing wheel to the mass of the powder is 1:1 to 2:1, the crushing speed is 100 to 150 r / min, and the crushing time is 40 to 60 minutes. The extrusion forming process involves feeding the block material obtained from the rolling unit into a screw extruder for extrusion forming to obtain a wet long strip material, with an extrusion speed of 2~5 cm / s; The drying and curing process involves drying the wet strip material obtained from the extrusion molding unit in a well-ventilated place to obtain dry strip material. The curing temperature is 20~50℃ and the curing time is 16~24 hours. The high-temperature roasting involves roasting the dried strip material obtained from the drying and curing unit in a continuous mesh belt kiln. The material is stacked to a height of 3-4 cm on the mesh belt, the roasting temperature is 500-700℃, and the roasting time is 5-10 hours to obtain a strip-shaped carrier. The carrier impregnation process includes five units: drum impregnation, high-temperature drying, high-temperature calcination, rolling pelletizing, and vibrating sieve powder removal; among which... The high-temperature calcination involves calcining the carrier obtained from the high-temperature drying unit of the carrier impregnation process in a continuous mesh belt kiln to obtain a strip-shaped catalyst. The carrier is stacked on the mesh belt at a height of 3-4 cm, the calcination temperature is 500-800℃, and the calcination time is 4-8 hours.

2. The method according to claim 1, characterized in that, After the rolling and lumping unit is completed during the carrier preparation process, the powder is lumped into blocks with a size of 5-15 cm.

3. The method according to claim 1, characterized in that, After the high-temperature calcination unit in the carrier preparation process, the average lateral compressive strength of the strip carrier is 120~180 N / cm.

4. The method according to claim 1, characterized in that, The carrier impregnation process involves pouring the strip-shaped carrier into an intermittent rotating drum, and then pouring an impregnation aqueous solution containing the metal precursor into the rotating drum for carrier impregnation.

5. The method according to claim 4, characterized in that, The metal is selected from one or more of the following: chromium, molybdenum, tungsten, copper, gold, silver, manganese, rhenium, zirconium, hafnium, cobalt, rhodium, iridium, gallium, indium, thallium, lanthanum, and cerium.

6. The method according to claim 4, characterized in that, The metal precursor is one or more of metal nitrates, metal ammonium salts, and metal carboxylates.

7. The method according to claim 4, characterized in that, The metal precursor is one or more of the following: copper nitrate trihydrate, lanthanum nitrate hexahydrate, ammonium tungstate pentahydrate, ammonium molybdate tetrahydrate, chromium nitrate nonahydrate, cobalt nitrate hexahydrate, zirconium nitrate dihydrate, manganese nitrate, ammonium chloroaurate trihydrate, silver nitrate, ammonium perrhenate, ammonium tetrabutyl hafnium tetrachlorooxyacetate, rhodium hexanoate, ammonium chloroiridate hexahydrate, gallium nitrate, indium nitrate tetrahydrate, thallium nitrate trihydrate, and cerium nitrate dihydrate.

8. The method according to claim 4, characterized in that, The mass ratio of the impregnation aqueous solution to the strip carrier is 1:1 to 1.4:1, the impregnation vacuum degree is 0.06 to 0.10 MPa, the impregnation temperature is 30 to 50°C, the impregnation time is 30 to 50 minutes, and the drum rotation speed is 2 to 4 r / min.

9. The method according to claim 4, characterized in that, After impregnation, while maintaining the vacuum and rotation speed of the drum, steam is introduced into the drum jacket to completely evaporate the impregnation liquid. The evaporation temperature is 90~120℃ and the evaporation time is 1~2 hours.

10. The method according to claim 1, characterized in that, The high-temperature drying during the carrier impregnation process involves drying the carrier obtained from the drum impregnation unit in a drying oven at a temperature of 100-120°C for 4-6 hours.

11. The method according to claim 1, characterized in that, The rolling pelletizing process during the carrier impregnation process involves pelletizing the strip-shaped catalyst obtained from the high-temperature calcination unit of the carrier impregnation process in a rolling pelletizer with a rotation speed of 100~200 r / min.

12. The method according to claim 1, characterized in that, The de-powdering process during the carrier impregnation process involves sieving out the broken and pulverized catalyst obtained from the rolling pelletizing unit in a vibrating screen.

13. The method according to claim 12, characterized in that, In the vibrating screen de-powdering unit of the carrier impregnation process, the aperture size of the vibrating screen is not higher than the diameter of the carrier, the proportion of catalyst crushing and pulverization is 2%~8%, and the average lateral pressure strength of the catalyst is 120~180 N / cm.

14. A method for molding a carrier in industrial production, characterized in that, It includes five units: strong mixing of raw materials, crushing into blocks, extrusion molding, drying and curing, and high-temperature roasting; among them, The high-intensity mixing of the raw materials is performed using a drum-type high-intensity mixer with a rotor. The dry powder material is high-intensity mixed for 20-30 minutes at a rotor speed of 80-120 r / min and a drum rotation speed of 60-100 r / min. Then, liquid material is added through a liquid inlet without changing the mixing speed. Finally, the rotor speed is increased to 300-400 r / min and the drum rotation speed is increased to 100-150 r / min, resulting in a high-intensity mixing time of 45-60 minutes. In the drum-type high-intensity mixer, the rotor and drum rotate in opposite directions. The process of crushing into blocks involves pouring the powder obtained from the raw material high-intensity mixing unit into a crushing machine for crushing. The weight ratio of the crushing wheel to the mass of the powder is 1:1 to 2:1, the crushing speed is 100 to 150 r / min, and the crushing time is 40 to 60 minutes. Extrusion molding involves feeding the block material obtained by crushing into block units into a screw extruder to form wet long strips of material. The extrusion speed is 2~5 cm / s. Air drying and curing involves air drying the wet strip material obtained from the extrusion molding unit in a well-ventilated place to obtain dry strip material. The curing temperature is 20~50℃ and the curing time is 16~24 hours. High-temperature roasting involves roasting the dried strips of material obtained from the drying and curing unit in a continuous mesh belt kiln. The material is stacked to a height of 3-4 cm on the mesh belt, the roasting temperature is 500-700℃, and the roasting time is 5-10 hours, resulting in strip-shaped carriers.

15. The method for forming a carrier according to claim 14, characterized in that, After the crushing and lumping unit is completed, the powder is lumped into blocks with a size of 5-15 cm.

16. The hydrogen peroxide decomposition catalyst obtained by the preparation method according to any one of claims 1 to 13.

17. A method for the decomposition reaction of hydrogen peroxide in an aqueous methanol solution, characterized in that... The hydrogen peroxide decomposition catalyst of claim 16 is used.

18. The method according to claim 17, characterized in that, The mass fraction of hydrogen peroxide in the methanol aqueous solution is 0.02~1.0%.

19. The method according to claim 18, characterized in that... The method is carried out in a fixed-bed reactor, wherein the feed mass hourly space velocity of the methanol-water solution is 1–10 h⁻¹. -1 The reaction temperature is 20~100℃.