A high-temperature-resistant catalytic oxidation catalyst and a preparation method thereof

Abstract

The application relates to a high-temperature-resistant catalytic oxidation catalyst and a preparation method thereof, which comprises the following steps: (1) treating 5A molecular sieve by immersing in a lithium salt solution to obtain Li-5A molecular sieve; then treating the Li-5A molecular sieve by immersing in a titanium salt solution to obtain Li-Ti-5A molecular sieve; finally, immersing the Li-Ti-5A molecular sieve in an active metal solution, adjusting the pH value to above 10 to obtain a Li-Ti-5A composite catalytic material; mixing the composite catalytic material with an organic polymer, dilute nitric acid and sesbania powder to form a shape, and drying and calcining to obtain the high-temperature-resistant catalytic oxidation catalyst. The catalytic oxidation catalyst provided by the application can realize efficient catalytic oxidation of low-carbon hydrocarbons at 450-700 DEG C, and has good high-temperature-resistant catalytic activity and stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of atmospheric pollution control, and particularly relates to a high-temperature-resistant catalytic oxidation catalyst and a preparation method thereof. BACKGROUND

[0002] Volatile organic compounds (VOCs) are one of the main atmospheric pollutants, which refer to organic compounds with a saturated vapor pressure greater than 70 KPa at room temperature and a boiling point below 260℃ at normal pressure. VOCs are of many types, mainly including aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, etc. As a kind of VOCs, low-carbon hydrocarbons mainly refer to methane, ethane, propane, etc., which are usually difficult to be treated by recovery and are generally treated by deep purification methods such as incineration, thermal incineration or catalytic oxidation. Catalytic oxidation technology is an efficient method for treating low-carbon hydrocarbons, and the key is the catalyst. However, due to the short carbon chain of low-carbon hydrocarbons and the high bond energy of C-H bond, the reaction temperature is generally higher than that of other VOCs, and the catalyst needs to have good high-temperature resistance.

[0003] CN111266100A discloses an ethane catalytic combustion monolithic catalyst and a preparation method thereof. The catalyst uses cordierite honeycomb ceramic as the carrier, SiO2 as the transition coating layer, active Al2O3 as the coating layer, and Pd and samarium oxide as the active components. The catalyst can be used for catalytic combustion of low-carbon alkanes such as ethane and benzene and aromatic hydrocarbons, has high activity and stability, and the removal rate of low-carbon hydrocarbons such as ethane and propane can reach more than 99% at a reaction temperature of 300-500℃. The catalyst maintains good catalytic conversion stability within 500h. However, the catalyst still needs to use noble metal as the main active component, and the cost is relatively high. Moreover, the high-temperature resistance is limited.

[0004] CN113070071A discloses a high-thermal-stability propane low-temperature catalytic combustion catalyst, a preparation method and application thereof. The catalyst is Co3O4 / SmMn2O5 with a loading amount of 30%. The high-thermal-stability temperature of the catalyst is 400-1000℃, that is, the catalyst can be recycled for 24h at 400-1000℃ without deformation. The catalyst can be used for propane low-temperature catalytic combustion, and the temperature for achieving 90% conversion rate of propane is only 200-230℃. The preparation method of the catalyst is as follows: under room temperature conditions, using samarium nitrate hexahydrate and manganese acetate tetrahydrate as raw materials, a carrier mullite (SmMn2O5) is obtained by deposition precipitation method; then, using the mullite and cobalt nitrate as precursors, Co3O4 / SmMn2O5 is obtained by deposition precipitation method. When the loading amount is 30%, Co3O4 / SmMn2O5 is the optimal catalyst. However, the catalytic conversion efficiency of the catalyst on ethane is not involved, and the catalyst is essentially a low-temperature catalyst with a high-temperature resistance time of only 24h.

[0005] CN110833833A discloses a non-noble metal composite oxide honeycomb catalyst for low-carbon hydrocarbon catalytic combustion, which takes cordierite honeycomb ceramic as a matrix and is coated with a Cu-Mn-Ce composite oxide coating; the active component Cu-Mn-Ce composite oxide in the catalyst is prepared by a hydrothermal method with ethylenediamine as a hydrothermal oriented precipitator, and then the composite oxide honeycomb catalyst is prepared through pulp preparation, dip coating, drying and calcination; the catalyst has good catalytic combustion activity for low-carbon hydrocarbons such as methane, ethane, propane, ethylene, propylene and n-hexane, can replace noble metal catalysts, and has good practical value. However, the catalyst can be stably operated at a temperature of 505 DEG C for 580 h without obvious attenuation; that is, the operating stability will decrease when the temperature is higher than 505 DEG C. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a high-temperature-resistant catalytic oxidation catalyst and a preparation method thereof. The catalytic oxidation catalyst provided by the present application can be used in a high-temperature environment up to 700 DEG C, can realize efficient catalytic oxidation of low-carbon hydrocarbons at 450-700 DEG C, and has good high-temperature-resistant catalytic activity and stability.

[0007] The present application provides a preparation method of a high-temperature-resistant catalytic oxidation catalyst, which comprises the following steps:

[0008] (1) treating 5A molecular sieve in a lithium salt solution, taking out, washing, drying and calcining to obtain Li-5A molecular sieve;

[0009] (2) treating the Li-5A molecular sieve in a titanium salt solution, taking out, washing, drying and calcining to obtain Li-Ti-5A molecular sieve;

[0010] (3) immersing the Li-Ti-5A molecular sieve in an active metal solution, adjusting the pH value to above 10, and then drying and calcining to obtain Li-Ti-5A composite catalytic material;

[0011] (4) mixing the Li-Ti-5A composite catalytic material with an organic polymer, dilute nitric acid and sesbania powder, and then drying and calcining to obtain the high-temperature-resistant catalytic oxidation catalyst.

[0012] In the method of the present application, the 5A molecular sieve in step (1) has the following properties: a specific surface area of 400-550 m 2 / g, preferably 500-550 m 2 / g, a pore volume of 0.2-0.5 cm 3 / g, preferably 0.28-0.35 cm 3 / g, and an average pore diameter of 1-3 nm. The 5A molecular sieve can be obtained by self-preparation or commercial purchase, and can be prepared by a hydrothermal method.

[0013] In the method, the lithium salt solution in step (1) is at least one of lithium chloride solution, lithium nitrate solution, lithium sulfate solution, etc., and preferably lithium chloride solution. The concentration of the lithium salt solution is generally 0.25-1.8 mol / L, and preferably 0.4-1.25 mol / L.

[0014] In the method, the mass-volume ratio of the 5A molecular sieve to the lithium salt solution in step (1) is 1 g:2-15 mL, and preferably 1 g:3-10 mL.

[0015] In the method, the 5A molecular sieve in step (1) is treated by being immersed in the lithium salt solution, and the treatment temperature is 60-90°C, and preferably 70-80°C; the treatment time is 1-5 h, and preferably 1-2 h.

[0016] In the method, the titanium salt in step (2) is at least one of soluble titanium salts, such as titanium tetrachloride, titanyl sulfate, titanium oxalate, etc., and preferably titanium tetrachloride. The titanium content in the titanium salt solution is 0.03-0.4 mol / L, and preferably 0.15-0.25 mol / L.

[0017] In the method, the mass-volume ratio of the Li-5A molecular sieve to the titanium salt solution in step (2) is 1 g:10-20 mL, and preferably 1 g:5-20 mL.

[0018] In the method, the Li-5A molecular sieve in step (2) is treated by being immersed in the titanium salt solution, and the treatment temperature is 10-40°C, and preferably 15-30°C; the treatment time is 1-5 h, and preferably 1-2 h.

[0019] In the method, the washing in steps (1) and (2) is performed by using a conventional method in the art, such as using deionized water to wash until no lithium or titanium ions are detected; the drying conditions are as follows: the drying temperature is 70-120°C, and preferably 80-100°C; the drying time is 2-10 h, and preferably 2-5 h; and the calcination conditions are as follows: the calcination temperature is 450-600°C, and preferably 500-550°C; and the calcination time is 1-10 h, and preferably 2-6 h.

[0020] In the method, the active metal in step (3) is Cu, Cr, and Ce, and the active metal solution is at least one of soluble metal salt solutions thereof, such as at least one of nitrate, chloride, etc., and preferably nitrate. The concentration of Cu ions in the active metal solution is 0.5-2.5 mmol / L, and preferably 1.25-2 mmol / L, and the molar ratio of Cu:Cr:Ce is 1:0.75-1.25:1-2.

[0021] In the method, the mass-volume ratio of the Li-Ti-5A molecular sieve to the active metal solution in step (3) is 1 g:30-120 mL, preferably 1 g:50-100 mL.

[0022] In the method, the pH value is adjusted to above 10, preferably 10-11 in step (3). The pH value is preferably adjusted by using ammonia water or the like.

[0023] In the method, the drying condition in step (3) is that the drying temperature is 60-100℃, preferably 80-100℃, and the drying time is 2-6h, preferably 2-4h. The calcination condition is that the calcination temperature is 450-600℃, preferably 500-550℃, and the calcination time is 1-6h, preferably 2-4h.

[0024] In the method, the mass ratio of the Li-Ti-5A composite catalytic material to the organic polymer, dilute nitric acid and sesbania powder in step (4) is 100:1-3:5-10:1-5, preferably 100:1.5-2:5-8:2-4.

[0025] In the method, the organic polymer in step (4) is at least one of hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like, and the hydroxypropyl cellulose is preferred.

[0026] In the method, the pH value of the dilute nitric acid in step (4) is 1-4, preferably 1.5-2.5.

[0027] In the method, the shaping in step (4) is to prepare the catalyst into granular or honeycomb shape, and the shaping is specifically according to the actual needs.

[0028] In the method, the drying condition in step (4) is that the drying temperature is 40-80℃, preferably 40-60℃, and the drying time is 6-12h, preferably 8-12h. The calcination condition is that the calcination temperature is 400-500℃, preferably 400-450℃, and the calcination time is 1-3h, preferably 1-2h.

[0029] The high-temperature-resistant catalytic oxidation catalyst is prepared by the method of the application. In the prepared catalyst, the content of Cu is 0.45%-2.1%, the content of Cr is 0.75%-3.15%, the content of Ce is 0.9%-4.7%, the content of Li is 0.6%-3.9%, and the content of Ti is 0.1%-0.8%, based on the total mass of the catalyst.

[0030] The high-temperature-resistant catalytic oxidation catalyst prepared by the application has good high-temperature-resistant catalytic activity and stability, and is used for catalytic oxidation of low-carbon hydrocarbons. The reaction temperature is 450-700℃, the volume space velocity is 5000-10000h-1, and the conversion rate of low-carbon hydrocarbons is 99.5%-99.9%. -1The low carbon hydrocarbon is mainly C2-C4 low carbon hydrocarbon, and specifically at least one of ethane and propane.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] (1) According to the characteristics of 5A molecular sieve, first modify by lithium salt, and then modify by titanium salt to obtain a dual-component modified Li-Ti-5A molecular sieve carrier, not only the pore size is close to the molecular kinetic size of small molecule VOCs, most of the pore size is 0.4-0.6 nm, but also the surface charge is changed, the electronegativity is weakened, and the selective adsorption capacity of small molecule VOCs is strengthened, thereby promoting the high-temperature catalytic oxidation of low carbon hydrocarbon of the prepared catalyst.

[0033] (2) Using Ti with a size close to the atomic size to replace Ca in the framework of 5A molecular sieve improves the surface properties without affecting the pore structure, has high high-temperature resistance, and effectively increases the loading and dispersion of active metal components, which helps to improve the catalytic activity and stability of the catalyst.

[0034] (3) Loading the active metal component with a specific composition on the dual-component modified Li-Ti-5A molecular sieve to prepare a Cu-Cr-Ce / Li-Ti-5A composite catalyst, which can be used in a high-temperature environment up to 700℃, and can realize efficient catalytic oxidation of low carbon hydrocarbon at 500-700℃. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is the removal rate effect diagram of low carbon hydrocarbon within 1000h in test example 2 of the present application. DETAILED DESCRIPTION

[0036] The technical scheme of the present application and its effects will be further illustrated by the following examples. The examples are implemented on the premise of the technical scheme of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0037] In the following examples, the experimental methods are conventional methods in the art unless otherwise specified. The experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified.

[0038] The contents of Cu, Cr, Ce, Li and Ti in the examples of the present application are obtained by ICP-OES analysis. The contents of ethane and propane are obtained by mass spectrometer test, and the concentration of non-methane total hydrocarbon is obtained by total hydrocarbon analyzer.

[0039] Example 1

[0040] Take commercially purchased 5A molecular sieve, and its properties are as follows: specific surface area: 540m 2 / g, pore volume: 0.34 cm 3 / g, average pore size: 2.15 nm.

[0041] The preparation process of the catalyst is as follows:

[0042] (1) The 5A molecular sieve is immersed in a LiCl solution with a concentration of 1 mol / L, the mass-volume ratio of the 5A molecular sieve to the lithium salt solution is 1 g:7 mL, and the treatment is carried out at 75°C for 1 hour. After being taken out, the deionized water is used for cleaning until no lithium ion is detected, and then the 5A molecular sieve is dried at 100°C for 4 hours and calcined at 500°C for 6 hours to obtain the Li-5A molecular sieve.

[0043] (2) The Li-5A molecular sieve is immersed in a titanium tetrachloride solution with a titanium content of 0.2 mol / L, the mass-volume ratio of the Li-5A molecular sieve to the titanium tetrachloride solution is 1 g:15 mL, and the treatment is carried out at 20°C for 2 hours. After being taken out, the deionized water is used for cleaning until no titanium ion is detected, and then the Li-5A molecular sieve is dried at 100°C for 4 hours and calcined at 500°C for 5 hours to obtain the Li-Ti-5A molecular sieve.

[0044] (3) The Li-Ti-5A molecular sieve is immersed in a solution of copper nitrate, chromium nitrate and cerium nitrate, the concentration of Cu ions in the solution is 1.5 mmol / L, the molar ratio of Cu:Cr:Ce is 1:1:1, the mass-volume ratio of the Li-Ti-5A molecular sieve to the active metal solution is 1 g:80 mL, and the pH value is adjusted to 10 by using ammonia water. The Li-Ti-5A molecular sieve is dried at 80°C for 4 hours and calcined at 530°C for 3 hours to obtain the Li-Ti-5A composite catalytic material.

[0045] (4) The composite catalytic material is mixed with hydroxypropyl cellulose, dilute nitric acid (pH 2.5) and sesbania powder according to the mass ratio of 100:2:8:3, and is extruded into a 200-mesh honeycomb shape. The honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst is obtained by drying at 60°C for 10 hours and calcining at 450°C for 1.5 hours.

[0046] In the prepared catalyst, the content of Cu is 1.29%, the content of Cr is 2.08%, the content of Ce is 2.83%, the content of Li is 3.05%, and the content of Ti is 0.52% based on the total mass of the catalyst. The catalyst performance test is shown in Table 1.

[0047] Example 2

[0048] The commercially purchased 5A molecular sieve has the following properties: specific surface area: 508 m 2 / g, pore volume: 0.28 cm 3 / g, average pore size: 2.2 nm.

[0049] The preparation process of the catalyst is as follows:

[0050] (1) 5A molecular sieve was immersed in a LiCl solution with a concentration of 0.25 mol / L, the mass-volume ratio of 5A molecular sieve to lithium salt solution was 1 g:10 mL, and the treatment was carried out at 60°C for 2 hours. After being taken out, the 5A molecular sieve was washed with deionized water until no lithium ion was detected, and then dried at 80°C for 8 hours and calcined at 600°C for 2 hours to obtain Li-5A molecular sieve.

[0051] (2) The Li-5A molecular sieve was immersed in a titanium tetrachloride solution with a titanium content of 0.4 mol / L, the mass-volume ratio of Li-5A molecular sieve to titanium tetrachloride solution was 1 g:10 mL, and the treatment was carried out at 25°C for 4 hours. After being taken out, the Li-5A molecular sieve was washed with deionized water until no titanium ion was detected, and then dried at 110°C for 2 hours and calcined at 600°C for 2 hours to obtain Li-Ti-5A adsorbent material.

[0052] (3) The Li-Ti-5A molecular sieve was immersed in a solution of copper nitrate, chromium nitrate and cerium nitrate, the concentration of Cu ion in the solution was 1.5 mmol / L, the molar ratio of Cu:Cr:Ce was 1:1:1, the mass-volume ratio of Li-Ti-5A molecular sieve to active metal solution was 1 g:80 mL, and the pH value was adjusted to 10 by using ammonia water. The solution was dried at 80°C for 4 hours and calcined at 530°C for 3 hours to obtain Li-Ti-5A composite catalytic material.

[0053] (4) The composite catalytic material was mixed with hydroxypropyl cellulose, dilute nitric acid (pH 2.5) and sesbania powder according to a mass ratio of 100:2:8:3, and then extruded into a 200-mesh honeycomb shape. The honeycomb was dried at 60°C for 10 hours and calcined at 450°C for 1.5 hours to obtain a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst.

[0054] In the prepared catalyst, the content of Cu was 1.31%, the content of Cr was 2.09%, the content of Ce was 2.85%, the content of Li was 0.61%, and the content of Ti was 0.78% based on the total mass of the catalyst. The performance test of the catalyst is shown in Table 1.

[0055] Example 3

[0056] A commercially available 5A molecular sieve was taken, and its properties were as follows: specific surface area: 550 m 2 / g, pore volume: 0.35 cm 3 / g, average pore size: 2.18 nm.

[0057] The preparation process of the catalyst was as follows:

[0058] (1) 5A molecular sieve was immersed in a LiCl solution with a concentration of 1.8 mol / L, the mass-volume ratio of 5A molecular sieve to lithium salt solution was 1 g:3 mL, and the treatment was carried out at 90°C for 1.5 hours. After being taken out, the 5A molecular sieve was washed with deionized water, dried at 120°C for 2 hours, and calcined at 450°C for 8 hours to obtain Li-5A molecular sieve.

[0059] (2) Li-5A molecular sieve was immersed in titanium tetrachloride solution with a titanium content of 0.03 mol / L, the mass-volume ratio of Li-5A molecular sieve to titanium tetrachloride solution was 1 g:20 mL, the treatment was carried out at 20℃ for 5 h, after taking out, the Li-5A molecular sieve was washed with deionized water, dried at 120℃ for 3 h, and calcined at 450℃ for 8 h to obtain Li-Ti-5A adsorbent material.

[0060] (3) Li-Ti-5A molecular sieve was immersed in a solution of copper nitrate, chromium nitrate and cerium nitrate, the concentration of Cu ions in the solution was 1.5 mmol / L, the molar ratio of Cu:Cr:Ce was 1:1:1, the mass-volume ratio of Li-Ti-5A molecular sieve to active metal solution was 1 g:80 mL, ammonia water was used to adjust the pH value to 10, dried at 80℃ for 4 h, and calcined at 530℃ for 3 h to obtain Li-Ti-5A composite catalytic material.

[0061] (4) The composite catalytic material was mixed with hydroxypropyl cellulose, dilute nitric acid (pH 2.5) and sesbania powder according to a mass ratio of 100:2:8:3, extruded into 200 mesh honeycomb shape, dried at 60℃ for 10 h, and calcined at 450℃ for 1.5 h to obtain a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst.

[0062] In the prepared catalyst, the content of Cu was 1.26%, the content of Cr was 2.05%, the content of Ce was 2.8%, the content of Li was 3.87%, and the content of Ti was 0.13% based on the total mass of the catalyst. The catalyst performance test is shown in Table 1.

[0063] Example 4

[0064] The same as Example 1, except that in step (1), lithium sulfate was used as lithium salt, to obtain a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst. The catalyst performance test is shown in Table 1.

[0065] Example 5

[0066] The same as Example 1, except that in step (1), lithium nitrate was used as lithium salt, to obtain a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst. The catalyst performance test is shown in Table 1.

[0067] Example 6

[0068] The same as Example 1, except that in step (1), titanium sulfate was used as titanium salt, to obtain a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst. The catalyst performance test is shown in Table 1.

[0069] Example 7

[0070] The same as Example 1, except that in step (1), titanium oxalate was used as titanium salt, to obtain a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst. The catalyst performance test is shown in Table 1.

[0071] Example 8

[0072] Similar to Example 1, except that the concentration of Cu in the solution in step (3) was 0.65 mmol / L, and the molar ratio of Cu:Cr:Ce was 1:1.25:1. In the prepared catalyst, based on the total mass of the catalyst, the content of Cu was 0.49%, the content of Cr was 0.89%, the content of Ce was 0.95%, the content of Li was 3.06%, and the content of Ti was 0.5%. The catalyst performance tests are shown in Table 1.

[0073] Example 9

[0074] Similar to Example 1, except that the concentration of Cu in the solution in step (3) was 2.48 mmol / L, and the molar ratio of Cu:Cr:Ce was 1:0.75:1. In the prepared catalyst, based on the total mass of the catalyst, the content of Cu was 2.08%, the content of Cr was 2.86%, the content of Ce was 4.67%, the content of Li was 3.88%, and the content of Ti was 0.14%. The catalyst performance tests are shown in Table 1.

[0075] Example 10

[0076] Similar to Example 1, except that in step (4), the mass ratio of the composite catalyst material to the organic polymer, dilute nitric acid, and guar gum powder is 100:1:10:5. In the prepared catalyst, based on the total mass of the catalyst, the content of Cu is 0.98%, the content of Cr is 1.57%, the content of Ce is 2.15%, the content of Li is 2.38%, and the content of Ti is 0.41%. The catalyst performance tests are shown in Table 1.

[0077] Example 11

[0078] Similar to Example 1, except that in step (4), the mass ratio of the composite catalyst material to the organic polymer, dilute nitric acid, and guar gum powder is 100:3:5:1. In the prepared catalyst, based on the total mass of the catalyst, the content of Cu is 1.94%, the content of Cr is 2.98%, the content of Ce is 4.25%, the content of Li is 3.72%, and the content of Ti is 0.76%. The catalyst performance tests are shown in Table 1.

[0079] Example 12

[0080] Similar to Example 1, except that in step (3), sodium hydroxide was used instead of ammonia to adjust the pH, thus obtaining a honeycomb-shaped high-temperature resistant catalytic oxidation catalyst. The catalyst performance test results are shown in Table 1.

[0081] Comparative Example 1

[0082] The same as example 1, except that only step (1), step (3) and step (4) are implemented, step (2) is omitted, and the catalyst prepared does not contain Ti. The catalyst performance test is shown in Table 1.

[0083] Comparative Example 2

[0084] The same as example 1, except that only step (2), step (3) and step (4) are implemented, step (1) is omitted, and the catalyst prepared does not contain Li. The catalyst performance test is shown in Table 1.

[0085] Comparative Example 3

[0086] The same as example 1, except that the 5A molecular sieve is first treated with a titanium salt and then treated with a lithium salt to finally obtain the catalyst. The catalyst performance test is shown in Table 1.

[0087] Comparative Example 4

[0088] The same as example 1, except that the lithium salt treatment temperature is 35 degrees, and a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst is prepared. The catalyst performance test is shown in Table 1.

[0089] Comparative Example 5

[0090] The same as example 1, except that an aluminum salt is used instead of a titanium salt to prepare a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst, and the catalyst performance test is shown in Table 1.

[0091] Comparative Example 6

[0092] The same as example 1, except that ZSM-5 molecular sieve is used instead of 5A molecular sieve to prepare a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst, and the catalyst performance test is shown in Table 1.

[0093] Comparative Example 7

[0094] The same as example 1, except that the pH in step (3) is adjusted to 9.0 to prepare a honeycomb-shaped high-temperature-resistant catalytic oxidation catalyst, and the catalyst performance test is shown in Table 1.

[0095] Test Example 1

[0096] The catalysts prepared in examples 1-12 and comparative examples 1-7 are tested for performance. In the treated gas, the ethane concentration is 1000 mg / m 3 , the propane concentration is 1000 mg / m 3 , the reaction conditions are: space velocity 7500 h -1 , reaction temperature is 500-700℃, and the low-carbon hydrocarbon removal rate after 1000h of operation is shown in Table 1.

[0097] Table 1 Experimental results of examples and comparative examples

[0098]

[0099] Test Example 2

[0100] Reaction conditions: 1000 mg / m³ of ethane 3 Propane 1000 mg / m³ 3 airspeed 10000h -1 The reaction temperature was 680℃, and the removal rate of low-carbon hydrocarbons was tested within 1000 hours as follows: Figure 1 As shown. By Figure 1 It can be seen that the catalyst of the present invention has good high temperature resistance and its catalytic activity has not decreased after long-term operation.

Claims

1. A method for preparing a high-temperature resistant catalytic oxidation catalyst, characterized in that... Includes the following steps: (1) The 5A molecular sieve was immersed in a lithium salt solution for treatment at a temperature of 60-90℃ for 1-5 hours; after removal, it was washed, dried, and calcined to obtain Li-5A molecular sieve; the 5A molecular sieve has the following properties: specific surface area of ​​400-550 m² 2 / g, pore volume 0.2~0.5cm 3 / g, with an average pore size of 1–3 nm; (2) The Li-5A molecular sieve was immersed in a titanium salt solution for treatment at a temperature of 10-40℃ for 1-5 hours; after being taken out, washed, dried and calcined, the Li-Ti-5A molecular sieve was obtained. (3) The Li-Ti-5A molecular sieve was impregnated in an active metal solution, the pH value was adjusted to 10-11, and the Li-Ti-5A composite catalytic material was obtained after drying and calcination; the active metals were Cu, Cr and Ce, and the molar ratio of Cu:Cr:Ce in the active metal solution was 1:0.75~1.25:1~2; (4) The Li-Ti-5A composite catalyst was mixed with organic polymer, dilute nitric acid and guar gum powder, and then dried and calcined to obtain a high-temperature resistant catalytic oxidation catalyst.

2. The method according to claim 1, characterized in that: The 5A molecular sieve in step (1) has the following properties: specific surface area of ​​500-550 m². 2 / g, pore volume 0.28~0.35cm³ 3 / g.

3. The method according to claim 1, characterized in that: In step (1), the lithium salt solution is at least one of lithium chloride solution, lithium nitrate solution, and lithium sulfate solution.

4. The method according to claim 1 or 3, characterized in that: The concentration of the lithium salt solution in step (1) is 0.25 to 1.8 mol / L.

5. The method according to claim 4, characterized in that: The concentration of the lithium salt solution in step (1) is 0.4 to 1.25 mol / L.

6. The method according to claim 1, 2 or 3, characterized in that: The mass-to-volume ratio of the 5A molecular sieve to the lithium salt solution in step (1) is 1g:2-15mL.

7. The method according to claim 6, characterized in that: The mass-to-volume ratio of the 5A molecular sieve to the lithium salt solution in step (1) is 1g:3-10mL.

8. The method according to claim 1, 2 or 3, characterized in that: In step (1), the 5A molecular sieve is immersed in a lithium salt solution for treatment at a temperature of 70-80°C for 1-2 hours.

9. The method according to claim 1, characterized in that: In step (2), the titanium salt is a soluble titanium salt.

10. The method according to claim 9, characterized in that: In step (2), the titanium salt is at least one of titanium tetrachloride, titanium oxysulfate, and titanium oxalate.

11. The method according to claim 1, 9, or 10, characterized in that: In step (2), the titanium content in the titanium salt solution is 0.03 to 0.4 mol / L.

12. The method according to claim 11, characterized in that: In step (2), the titanium content in the titanium salt solution is 0.15 to 0.25 mol / L.

13. The method according to claim 1, 9, or 10, characterized in that: In step (2), the mass-to-volume ratio of Li-5A molecular sieve to titanium salt solution is 1g:5-20mL.

14. The method according to claim 13, characterized in that: In step (2), the mass-to-volume ratio of Li-5A molecular sieve to titanium salt solution is 1g:10-20mL.

15. The method according to claim 1, 9, or 10, characterized in that: In step (2), the Li-5A molecular sieve is immersed in a titanium salt solution for treatment at a temperature of 15-30°C for 1-2 hours.

16. The method according to claim 1, characterized in that: In steps (1) and (2), washing is performed until no lithium or titanium ions are detected, using deionized water; the drying conditions are: drying temperature 70-120℃, drying time 2-10h; the calcination conditions are: calcination temperature 450-600℃, calcination time 1-10h.

17. The method according to claim 16, characterized in that: The drying temperature is 80-100℃ and the drying time is 2-5 hours; the calcination temperature is 500-550℃ and the calcination time is 2-6 hours.

18. The method according to claim 1, characterized in that: In step (3), the active metal solution is at least one of its soluble metal salt solutions.

19. The method according to claim 18, characterized in that: In step (3), the active metal solution is at least one of its nitrate or chloride.

20. The method according to claim 18 or 19, characterized in that: In step (3), the concentration of Cu ions in the active metal solution is 0.5–2.5 mmol / L.

21. The method according to claim 20, characterized in that: In step (3), the concentration of Cu ions in the active metal solution is 1.25–2 mmol / L.

22. The method according to claim 1, 18, or 19, characterized in that: In step (3), the mass-to-volume ratio of Li-Ti-5A molecular sieve to active metal solution is 1g:30-120mL.

23. The method according to claim 22, characterized in that: In step (3), the mass-to-volume ratio of Li-Ti-5A molecular sieve to active metal solution is 1g:50-100mL.

24. The method according to claim 1, characterized in that: Step (3) Adjust the pH using ammonia.

25. The method according to claim 1, characterized in that: The drying conditions in step (3) are: drying temperature 60-100℃, drying time 2-6h; the calcination conditions are: calcination temperature 450-600℃, calcination time 1-6h.

26. The method according to claim 25, characterized in that: The drying temperature is 80-100℃ and the drying time is 2-4 hours; the calcination temperature is 500-550℃ and the calcination time is 2-4 hours.

27. The method according to claim 1, characterized in that: The mass ratio of the Li-Ti-5A composite catalyst material to the organic polymer, dilute nitric acid, and guar gum powder in step (4) is 100:1~3:5~10:1~5.

28. The method according to claim 27, characterized in that: The mass ratio of the Li-Ti-5A composite catalyst material to the organic polymer, dilute nitric acid, and guar gum powder in step (4) is 100:1.5~2:5~8:2~4.

29. The method according to claim 1, 27, or 28, characterized in that: In step (4), the organic polymer is at least one of hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose; the pH value of the dilute nitric acid is 1 to 4.

30. The method according to claim 29, characterized in that: In step (4), the organic polymer is hydroxypropyl cellulose; the pH value of dilute nitric acid is 1.5 to 2.

5.

31. The method according to claim 1, characterized in that: The drying conditions in step (4) are: drying temperature 40-80℃, drying time 6-12h; the calcination conditions are: calcination temperature 400-500℃, calcination time 1-3h.

32. The method according to claim 31, characterized in that: The drying temperature is 40-60℃ and the drying time is 8-12h; the calcination temperature is 400-450℃ and the calcination time is 1-2h.

33. A high-temperature resistant catalytic oxidation catalyst, characterized in that... It is prepared using the method described in any one of claims 1-32.

34. The application of the catalyst according to claim 33, characterized in that: The prepared high-temperature resistant catalytic oxidation catalyst is used for the catalytic oxidation of low-carbon hydrocarbons at reaction temperatures of 450-700℃ and volume hourly space velocities of 5000-10000 h⁻¹. -1 .

35. The application of the catalyst according to claim 34, characterized in that: The low-carbon hydrocarbons mentioned are mainly C2-C4 low-carbon hydrocarbons.

36. The application of the catalyst according to claim 35, characterized in that: The low-carbon hydrocarbon is at least one of ethane and propane.

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