Preparation method and application of sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst

Abstract

The present invention provides a preparation method and application of an anti-sintering and anti-carbon deposition ethylbenzene catalyst, belonging to the field of catalyst technology. The preparation method includes: adding hexahydrate chloroplatinic acid, alkali metal nitrate and zirconium sulfate tetrahydrate into deionized water to prepare an impregnation solution; after calcining the HZSM-5 molecular sieve, adding it to the impregnation solution, stirring, standing and drying in sequence to obtain a solid impregnation product; grinding and calcining the solid impregnation product to obtain a modified molecular sieve; tableting the modified molecular sieve, granulating, and sieving to obtain an anti-sintering and anti-carbon deposition ethylbenzene catalyst. The obtained catalyst is used to react ethane and benzene to produce ethylbenzene, which solves the problem that the catalyst is easily deactivated by carbon deposition and the active metal is easily sintered when ethane and benzene react.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a preparation method and application of an anti-sintering and anti-carbon deposition ethylbenzene catalyst. Background Art

[0002] Ethane is abundant in sources. It is the second largest component of shale gas after methane. With the large-scale exploitation of shale gas, ethane production has also increased significantly. At the same time, ethane is also one of the main tail gases of industrial catalytic cracking. The abundant ethane resources have made ethane dehydrogenation to ethylene and further conversion to high-value-added benzene and ethylbenzene more and more important. Due to its considerable economic value, it has also driven the rapid development of research on multi-mode efficient conversion of low-carbon alkanes.

[0003] Since Pt has a strong activation effect on the carbon-hydrogen bonds of low-carbon chain alkanes, and also has a low activation effect on the cracking of carbon-carbon bonds of alkanes, it exhibits excellent catalytic dehydrogenation performance. However, when Pt is used as a dehydrogenation active metal, it is easy to sinter in high-temperature reactions, which reduces the catalytic efficiency. The literature Journal of Catalysis, 2000, 194 (2): 266-277. reported that Smirnov et al. explored the alkylation reaction of benzene and ethane on Pt / H-MFI catalyst. At 450°C, the conversion rate of benzene reached 12%, and the highest selectivity of ethylbenzene and total aromatics was about 27% and 43%, respectively, but the catalyst soon became deactivated.

[0004] The strong acid sites of HZSM-5 molecular sieve itself will produce a large number of high-carbon byproducts in the reaction of ethane and benzene, and the dehydrogenation polymerization will produce a large amount of carbon deposits, which will block the catalyst pores, occupy the B acid active sites, and inhibit the benzene alkylation reaction. The literature Catalysis Letters, 2001, 73 (2-4): 175-180. reported that Kato et al. studied the effect of temperature on the ethylbenzene yield of the alkylation of benzene and ethane on a molecular sieve catalyst loaded with platinum, and found that increasing the temperature is not conducive to the reaction and is prone to carbon deposits.

[0005] In addition, in the literature Study on the coupling reaction and catalyst of ethane dehydrogenation and benzene alkylation [D]. Beijing: Beijing University of Chemical Technology, 2022. Xu Lin et al. proposed a coupling reaction system of ethane dehydrogenation and benzene and prepared a Pt / ZSM-5 catalyst. The reaction produced ethylbenzene while promoting the ethane dehydrogenation reaction to obtain better ethylene selectivity. The catalyst used a relatively low silicon-aluminum ratio and did not use additives to adjust the acidity of the molecular sieve carrier, resulting in carbon deposition and deactivation of the catalyst during the reaction. At the same time, the dehydrogenation active metal Pt also sintered due to the high reaction temperature, which reduced the catalytic efficiency. Summary of the invention

[0006] The purpose of the present invention is to provide a preparation method and application of an ethylbenzene catalyst having resistance to sintering and carbon deposition; the preparation method improves the anti-sintering and anti-carbon deposition capabilities of the catalyst by adding an alkali metal nitrate additive and zirconium sulfate tetrahydrate to a Pt-based HZSM-5 molecular sieve catalyst; and obtains a suitable molecular sieve acidity range by regulating the molecular sieve silicon-aluminum ratio, thereby improving the catalytic performance of the catalyst and enabling the catalyst to have an excellent benzene conversion rate.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, comprising the following steps:

[0009] (1) adding chloroplatinic acid hexahydrate, alkali metal nitrate and zirconium sulfate tetrahydrate into deionized water to prepare an impregnation solution;

[0010] (2) After calcining the HZSM-5 molecular sieve, add it to the impregnation solution, stir, stand, and dry in sequence to obtain a solid impregnation product;

[0011] (3) grinding and calcining the solid impregnation product to obtain a modified molecular sieve;

[0012] (4) The modified molecular sieve is tableted, granulated, and sieved to obtain an anti-sintering and anti-carbon deposition ethylbenzene catalyst.

[0013] Furthermore, in the step (1), the alkali metal nitrate is any one of sodium nitrate, potassium nitrate or rubidium nitrate; and the mass volume ratio of metal ions to deionized water in chloroplatinic acid hexahydrate, alkali metal nitrate and zirconium sulfate tetrahydrate is 1g:0.5-1g:0.5-0.8g:150mL.

[0014] Furthermore, in the step (2), the calcination temperature is 300 to 500° C. and the time is 1 to 3 hours to remove the residual template and ammonium ions;

[0015] Furthermore, in the step (2), the usage ratio of HZSM-5 molecular sieve and impregnation solution is 97.2-98 g:150 mL;

[0016] Furthermore, in the step (2), the impregnation process adopts an excessive impregnation method; the constant temperature stirring temperature is 40 to 60°C, the rotation speed is 300 r / min, and the time is 2 to 4 hours to obtain a slurry mixture with uniform load; the standing time is 8 to 10 hours to allow the load to better enter the molecular sieve pores; the drying temperature is 110 to 130°C, and the time is 10 to 12 hours;

[0017] Furthermore, in step (2), the silicon-aluminum molar ratio of the HZSM-5 molecular sieve is 55 to 85:1.

[0018] Furthermore, in the step (3), the calcination treatment is carried out in air at a temperature of 400 to 500° C. for 3 to 5 hours, so that the load is fixed on the molecular sieve.

[0019] Furthermore, in the step (4), the modified molecular sieve is tableted, granulated, and sieved to obtain a catalyst particle size of 20 to 40 meshes.

[0020] The implementation of the present invention has at least the following beneficial effects:

[0021] (1) The present invention provides a method for preparing an anti-sintering and anti-carbon deposition ethylbenzene catalyst, wherein Pt, an alkali metal nitrate additive and a Zr additive are loaded onto a HZSM-5 molecular sieve, and the alkali metal in the alkali metal nitrate and Pt form a Pt-alkali metal alloy, thereby improving the dispersibility of the Pt metal and enhancing the anti-sintering ability of the Pt metal during the reaction process.

[0022] (2) The present invention provides a method for preparing a sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, wherein Pt, an alkali metal nitrate additive and a Zr additive are loaded onto a HZSM-5 molecular sieve. The Zr metal can adjust the acidity of the molecular sieve, reduce the generation of high-carbon by-products, improve the selectivity of ethylbenzene, effectively reduce carbon deposition on the molecular sieve, and avoid rapid deactivation of the catalyst.

[0023] (3) The present invention discloses a method for preparing an ethylbenzene catalyst that is resistant to sintering and carbon deposition. By screening molecular sieves with different silicon-aluminum ratios, it is found that when the molecular sieve silicon-aluminum molar ratio is between 55 and 85, the catalyst in the acidic range has good catalytic performance and the conversion rate of benzene is improved.

[0024] (4) The invention discloses an application of an anti-sintering and anti-carbon deposition ethylbenzene catalyst, which can react ethane with benzene to produce ethylbenzene at 380°C, with a benzene conversion rate of 18% and an ethylbenzene selectivity of 72%. The reaction temperature of ethane with benzene to produce ethylbenzene is lowered, which reduces energy consumption and improves reaction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 are transmission electron microscope (TEM) images; wherein, (a) is a transmission electron microscope (TEM) image of the 1.5Pt-0.8Rb-0.5Zr / HZSM-5(65) catalyst obtained in Example 1 before the reaction; (b) is a transmission electron microscope (TEM) image of the 1.5Pt-0.8Rb-0.5Zr / HZSM-5(65) catalyst obtained in Example 1 after the reaction; (c) is a transmission electron microscope (TEM) image of the 1.5Pt-0.5Zr / HZSM-5(65) catalyst obtained in Comparative Example 2 before the reaction; (d) is a transmission electron microscope (TEM) image of the 1.5Pt-0.5Zr / HZSM-5(65) catalyst obtained in Comparative Example 2 after the reaction;

[0026] Figure 2 Thermogravimetric (TG) graphs of the catalysts obtained in Example 1 and Comparative Example 1 after reaction;

[0027] Figure 3 This is a graph showing the change in benzene conversion over time for 1.5Pt-0.8Rb-0.5Zr / HZSM-5 catalysts with different silicon-aluminum ratios obtained in Example 1, Example 6, Comparative Example 4 and Comparative Example 5. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0029] In each embodiment and comparative example, the chemicals used are all commercially available chemically pure reagents. Example 1

[0030] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.8 g of rubidium in rubidium nitrate, and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0031] The purchased HZSM-5 (Si / Al=65) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was cooled to room temperature and then taken out. 97.7 g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0032] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0033] The modified molecular sieve was loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8Rb-0.5Zr / HZSM-5(65). Example 2

[0034] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.8 g of sodium in sodium nitrate, and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place the mixture in an ultrasonic cleaner for 5 minutes to dissolve it evenly, thereby obtaining the required impregnation solution.

[0035] The HZSM-5 (Si / Al=55) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 97.7g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 8 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0036] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0037] The modified molecular sieve was loaded into a tabletting mold and tabletted using a tabletting machine to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8Na-0.5Zr / HZSM-5(55). Example 3

[0038] Weigh 1 g of platinum-containing chloroplatinic acid hexahydrate, 0.5 g of potassium-containing potassium nitrate, and 0.5 g of zirconium-containing zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place the mixture in an ultrasonic cleaner for 5 minutes to dissolve it evenly, thereby obtaining the required impregnation solution.

[0039] The HZSM-5 (Si / Al=75) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2h to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 98g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2h. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 9h to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12h to obtain a solid impregnation product.

[0040] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0041] The modified molecular sieve was loaded into a tabletting mold and tabletted using a tabletting machine to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8K-0.5Zr / HZSM-5(75). Example 4

[0042] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.5 g of rubidium in rubidium nitrate, and 0.8 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0043] The HZSM-5 (Si / Al=65) molecular sieve was placed in a muffle furnace and calcined at 300°C for 2h to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 97.7g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 55°C, and stirred at 300r / min for 2.5h. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 8h to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 110°C, and it was dried for 11.5h to obtain a solid impregnation product.

[0044] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 5h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0045] The modified molecular sieve was loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.5Rb-0.8Zr / HZSM-5(65). Example 5

[0046] Weigh 1g of platinum in hexahydrate chloroplatinic acid, 1g of rubidium in rubidium nitrate, and 0.8g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0047] The HZSM-5 (Si / Al=75) molecular sieve was placed in a muffle furnace and calcined at 450°C for 2.5 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 97.2g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 45°C, and stirred at 300r / min for 3 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 9 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 125°C, and it was dried for 11 hours to obtain a solid impregnation product.

[0048] After drying, the beaker was taken out after cooling to room temperature, the solid in the beaker was taken out, and the solid impregnation product was ground into powder with an agate mortar, then placed in a crucible, and placed in a muffle furnace to keep calcining at 450°C for 3.5h. After calcination, it was cooled to room temperature to obtain a modified molecular sieve.

[0049] The modified molecular sieve is loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve is crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which is recorded as 1Pt-1Rb-0.8Zr / HZSM-5(75). Example 6

[0050] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.8 g of rubidium in rubidium nitrate, and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0051] The HZSM-5 (Si / Al=85) molecular sieve was placed in a muffle furnace and calcined at 500°C for 1 hour to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 97.7g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 40°C, and stirred at 300r / min for 4 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 130°C, and it was dried for 10 hours to obtain a solid impregnation product.

[0052] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 500°C for 3h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0053] The modified molecular sieve was loaded into a tabletting mold and tabletted using a tabletting machine to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8Rb-0.5Zr / HZSM-5(85). Comparative Example 1

[0054] Weigh hexahydrate chloroplatinic acid containing 1g of platinum and rubidium nitrate containing 0.8g of rubidium into a beaker, add 150mL of deionized water, put it into an ultrasonic cleaner and sonicate for 5 minutes to dissolve it evenly, so as to obtain the required impregnation solution.

[0055] The HZSM-5 (Si / Al=65) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was cooled to room temperature and then taken out. 98.2 g of the molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0056] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0057] The modified molecular sieve was loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8Rb / HZSM-5(65). Comparative Example 2

[0058] Weigh 1 g of platinum in chloroplatinic acid hexahydrate and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve it evenly, thereby obtaining the required impregnation solution.

[0059] The HZSM-5 (Si / Al=65) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 98.5g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0060] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0061] The modified molecular sieve was loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.5Zr / HZSM-5(65). Comparative Example 3

[0062] Weigh 1 g of platinum in chloroplatinic acid hexahydrate, add 150 mL of deionized water, put the mixture into an ultrasonic cleaner and perform ultrasonic cleaning for 5 minutes to make it evenly dissolved, so as to obtain the required impregnation solution.

[0063] The HZSM-5 (Si / Al=65) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 99g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0064] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0065] The modified molecular sieve was loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, recorded as 1.5Pt / HZSM-5(65). Comparative Example 4

[0066] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.8 g of rubidium in rubidium nitrate, and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0067] The HZSM-5 (Si / Al=45) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 97.7g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0068] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0069] The modified molecular sieve was loaded into a tableting mold and tableted using a tablet press to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8Rb-0.5Zr / HZSM-5(45). Comparative Example 5

[0070] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.8 g of rubidium in rubidium nitrate, and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0071] The HZSM-5 (Si / Al=100) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2 hours to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was taken out after cooling to room temperature, 97.7g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2 hours. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 10 hours to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12 hours to obtain a solid impregnation product.

[0072] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0073] The modified molecular sieve was loaded into a tabletting mold and tabletted using a tabletting machine to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, which was recorded as 1.5Pt-0.8Rb-0.5Zr / HZSM-5(100). Comparative Example 6

[0074] Weigh 1 g of platinum in hexahydrate chloroplatinic acid, 0.8 g of rubidium in rubidium nitrate, and 0.5 g of zirconium in zirconium sulfate tetrahydrate into a beaker, add 150 mL of deionized water, and place in an ultrasonic cleaner for 5 minutes to dissolve evenly to obtain the required impregnation solution.

[0075] The purchased HZSM-5 (Si / Al=65) molecular sieve was placed in a muffle furnace and calcined at 400°C for 2h to remove residual ammonium ions and template agents. After the calcination, the molecular sieve was cooled to room temperature and then taken out. 97.7g of molecular sieve was weighed and added to the impregnation liquid to obtain a mixed liquid. The beaker containing the mixed liquid was placed on a constant temperature stirring device, set at 60°C, and stirred at 300r / min for 2h. After the mixed liquid became viscous, it was removed, and the beaker was sealed with plastic wrap and allowed to stand for 4h to allow the load to better enter the molecular sieve pores. After the standing period, the beaker containing the above mixture was placed in a constant temperature drying oven, the drying temperature was set to 120°C, and it was dried for 12h to obtain a solid impregnation product.

[0076] After the drying is completed, the beaker is taken out after being cooled to room temperature, the solid in the beaker is taken out, the solid impregnation product is ground into powder with an agate mortar, and then placed in a crucible, placed in a muffle furnace and calcined at 400°C for 4h, and cooled to room temperature after calcination to obtain a modified molecular sieve.

[0077] The modified molecular sieve was loaded into a tabletting mold and tabletted using a tabletting machine to obtain a flaky solid modified molecular sieve. The flaky molecular sieve was crushed into granules and sieved using a 20-40 mesh stainless steel standard sieve to obtain the desired sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst, recorded as 1.5Pt-0.8Rb-0.5Zr / HZSM-5(65)- and allowed to stand for 4 hours.

[0078] Application Examples

[0079] The reaction of ethane and benzene to ethylbenzene is carried out in a continuous flow fixed bed reactor. First, a small amount of quartz wool is inserted into the middle of a high temperature resistant quartz glass tube with an inner diameter of 12 mm, 0.5 g of catalyst is added to the quartz glass tube, and then a small amount of quartz wool is inserted into the other side of the catalyst to fix it.

[0080] The quartz glass tube filled with the catalyst was placed in a fixed bed reactor, and a small amount of nitrogen was introduced for purging to replace the air in the reactor. The catalyst was then reduced with 99.99% hydrogen at a hydrogen gas rate of 40 mL / min, the temperature was set to 400 °C, and the reduction time was 2 h.

[0081] After the reduction is completed, the gas is switched to nitrogen after the temperature drops naturally, and the temperature is raised to 380°C and then the gas is switched to ethane and benzene. The reaction temperature is 380°C and the reaction pressure is 0.1 MPa. The raw gas space velocity is 1500 mL / (g cat •h), the ratio of ethane to benzene in the feed gas is 10.

[0082] The catalyst performance was evaluated using this application scheme, and the reaction results are shown in Table 1.

[0083]

[0084] Note: The conversion rate and product selectivity are all data for 8 hours of reaction.

[0085] By comparing the data of Example 1, Comparative Example 2 and Comparative Example 3 in Table 1, it can be seen that the C 10 The selectivity of by-products is 12.84%. After adding Zr additives in Example 1 and Comparative Example 2, the C 10 The selectivity of by-products decreased from 14.84% to 2.52% and 5.85% respectively, and the selectivity of ethylbenzene increased from 50.23% to 72.58%, indicating that the addition of Zr additive can inhibit the formation of high-carbon by-products and improve the selectivity of ethylbenzene.

[0086] By observing the TEM images of the catalyst before and after the reaction ( Figure 1 ), it can be seen that after adding Rb additive to the catalyst in Example 1 (Figure a, Figure b), the amount of Pt metal sintering and aggregation during the reaction is reduced, which improves the anti-sintering ability of Pt metal, allowing more Pt active sites to perform ethane dehydrogenation reaction, ensuring sufficient ethylene and benzene to perform alkylation reaction to produce ethylbenzene, and improving the stability of the catalyst. In Comparative Example 2, the catalyst (Figure c, Figure d) did not add Rb additive, and the particle size of Pt metal after the reaction was significantly increased.

[0087] Figure 2It is a thermogravimetric characterization analysis diagram after the catalyst reaction. It can be seen from the figure that the catalyst in Comparative Example 1 has no Zr additive, and its thermal weight loss reaches 5.02%. After adding the Zr additive, the catalyst in Example 1 has a thermal weight loss of 2.89%, and the carbon deposit amount of the catalyst is significantly reduced, indicating that adding the Zr additive can reduce the formation of catalyst carbon deposits, thereby improving the stability of the catalyst.

[0088] Figure 3 The time-varying diagram of the benzene conversion rate when ethane is prepared into ethylbenzene for catalysts with different silicon-aluminum ratios. As can be seen from the figure, the molecular sieve Si / Al of the catalyst in Example 1 is 65, and the benzene conversion rate can reach 18.5% at this time, and it remains stable within 22 hours without a significant decrease; the molecular sieve Si / Al of the catalyst in Example 6 is 85, and it also shows a good benzene conversion rate, which can reach more than 17%; the molecular sieve Si / Al of the catalyst in Comparative Example 4 is 45, and the initial conversion rate of benzene is very high at this time, but deactivation occurs quickly, which is considered to be due to the strong acidity of the molecular sieve. After adding the auxiliary agent for adjustment, the acidity is still high, and the aromatics in the product are further aromatized, resulting in a large amount of carbon deposits, resulting in a decrease in the benzene conversion rate; the molecular sieve Si / Al of the catalyst in Comparative Example 5 is 100, and the benzene conversion rate is low at this time, because with the increase of the silicon-aluminum ratio, the acidity of the molecular sieve decreases, and the B acid sites provided for the alkylation of benzene and ethylene are reduced, thereby reducing the benzene conversion rate.

Claims

1. A method for preparing a sintering and carbon deposition resistant ethylbenzene catalyst, characterized in that: The following steps are involved: (1) dissolving chloroplatinic acid hexahydrate, alkali metal nitrate and zirconium sulfate tetrahydrate in deionized water to prepare an impregnation solution; (2) calcining HZSM-5 molecular sieve, adding it to the impregnation solution, stirring it until it becomes viscous, standing it, and drying it to obtain a solid impregnation product; the silicon-aluminum molar ratio of the HZSM-5 molecular sieve is 55 to 85:1; (3) grinding and calcining the solid impregnation product to obtain a modified molecular sieve; (4) The modified molecular sieve is tableted, granulated, and sieved to obtain an anti-sintering and anti-carbon deposition ethylbenzene catalyst.

2. The method for preparing the sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst according to claim 1, characterized in that: In the step (1), the alkali metal nitrate is any one of sodium nitrate, potassium nitrate or rubidium nitrate; the mass volume ratio of metal ions to deionized water in chloroplatinic acid hexahydrate, alkali metal nitrate and zirconium sulfate tetrahydrate is 1g:0.5-1g:0.5-0.8g:150mL.

3. The method for preparing the sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst according to claim 1, characterized in that: In the step (2), the calcination temperature is 300-500° C., and the time is 1-3 hours; the amount ratio of HZSM-5 molecular sieve to impregnation solution is 97.2-98 g:150 mL.

4. The method for preparing the sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst according to claim 1, characterized in that: In the step (2), the stirring temperature is 40-60°C, the rotation speed is 300 r / min, and the time is 2-4 hours; the standing time is 8-10 hours; and the drying temperature is 110-130°C, and the time is 10-12 hours.

5. The method for preparing the sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst according to claim 1, characterized in that: In the step (3), the calcination temperature is 400-500° C. and the calcination time is 3-5 hours.

6. The method for preparing the sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst according to claim 1, characterized in that: In the step (4), the particle size of the anti-sintering and anti-carbon deposition ethylbenzene catalyst is 20 to 40 meshes.

7. Use of the sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst prepared by the preparation method according to any one of claims 1 to 6, characterized in that: The prepared sintering-resistant and carbon-deposition-resistant ethylbenzene catalyst is used in the reaction of ethane and benzene to prepare ethylbenzene.

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