Molecular sieve type catalyst as well as preparation method and application thereof

Abstract

The invention provides a molecular sieve type catalyst as well as a preparation method and application thereof. The molecular sieve type catalyst comprises a Y molecular sieve and a sulfated oxide of transition metal. The molecular sieve type catalyst is used for olefin removal of aromatic hydrocarbon, and solves the problems of carbon deposition inactivation, many side reactions, poor stability or incapability of giving consideration to both stability and activity of the catalyst in the alkylation reaction process in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly relates to a molecular sieve type catalyst, a preparation method thereof and an application thereof. Background Art

[0002] Aromatics are basic raw materials in the petrochemical industry, and mainly come from aromatics combined units. The aromatics products after catalytic reforming reaction all contain a certain amount of olefin impurities. Olefins are active, not only easily polymerize to form gum, but also may react with other components to generate non-ideal components, thus having a greater impact on the quality of aromatics products. In addition, some petrochemical process such as xylene adsorption separation process is particularly sensitive to olefins. Even if the content of olefin impurities is only a few parts per million, it will have a very adverse impact on the process. In order to obtain qualified chemical raw materials and ensure the smooth progress of subsequent processes, after the processes of reforming, aromatics extraction, isomerization, and toluene disproportionation, there are refining processes to remove trace olefin impurities.

[0003] Clay has acidic centers and has certain catalytic polymerization ability and pore adsorption ability under the conditions of high-pressure liquid phase and 150 - 200 °C, which can make the trace olefins contained in reformate undergo reactions such as alkylation and polymerization to generate high-boiling compounds, and then be adsorbed by the clay or removed in the subsequent separation process. However, the exploitation of clay and the aromatic clay after deactivation will cause serious pollution to the environment. Today, with the continuous strengthening of environmental awareness, production enterprises are urgently in need of catalytic de-olefination technologies that can solve these problems.

[0004] There have been literature reports on using molecular sieves as catalysts in de-olefination reactions, but these molecular sieve catalysts have problems such as carbon deposition deactivation, many side reactions, poor stability, or the inability to balance stability and activity. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a new molecular sieve type catalyst, a preparation method thereof and an application thereof. When the molecular sieve type catalyst provided by the present invention is used for aromatics de-olefination, it can effectively solve the problems of carbon deposition deactivation, many side reactions, poor stability, or the inability to balance stability and activity in the alkylation reaction process.

[0006] In a first aspect, the present application provides a molecular sieve type catalyst, which comprises Y molecular sieve and sulfated oxides of transition metals.

[0007] Y zeolite has supercages with an average effective diameter of 1.18 nm, which is much larger than the diameter of its main pore channels of 0.74 nm. As a result, linear macromolecules with smaller molecular diameters can be generated, and larger molecules with diameters in the range of 0.74 - 1.18 nm can also be generated. The rich and open pore structure of Y zeolite ensures its relatively large pore volume, thus guaranteeing a certain carbon-holding capacity of the zeolite and the service life of the zeolite catalyst. However, due to the relatively small pore mouth diameter of Y zeolite, the macromolecules generated during the olefin alkylation process cannot quickly escape from its pore channels and are prone to blockage at the pore mouths, causing the inactivation of Y zeolite. In the present invention, by loading the sulfated oxides of transition metals (especially sulfated zirconia) into Y zeolite, acid active centers rich in superacids can be introduced, the total acid amount and the amount of weak acids are significantly increased, the acidic active sites are significantly increased, the acidity is further enhanced, and a more efficient catalytic effect is achieved.

[0008] According to some embodiments, the specific surface area of the catalyst is 200 - 1000 m 2 / g, for example, 200 m 2 / / g, 300 m 2 / g, 400 m 2 / g, 500 m 2 / g, 600 m 2 / g, 700 m 2 / g, 800 m 2 / g, 900 m 2 / g, 1000 m 2 / g.

[0009] According to some embodiments, the specific surface area of the catalyst is 300 - 500 m 2 / g.

[0010] According to some embodiments, the specific surface area of the catalyst is 350 - 410 m 2 / g.

[0011] According to some embodiments, the average pore diameter of the catalyst is 0.5 - 15 nm, for example, 0.5 nm, 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm.

[0012] According to some embodiments, the average pore diameter of the catalyst is 0.7 - 10 nm.

[0013] According to some embodiments, the average pore diameter of the catalyst is 2.5 - 10 nm.

[0014] According to some embodiments, the total acid amount in the catalyst is greater than 1.0 mmol / g.

[0015] According to some embodiments, the total acid amount in the catalyst is 1.05 - 2 mmol / g; for example, it is 1.05 mmol / g, 1.08 mmol / g, 1.1 mmol / g, 1.15 mmol / g, 1.2 mmol / g, 1.25 mmol / g, 1.3 mmol / g, 1.4 mmol / g, 1.6 mmol / g, 1.8 mmol / g, 2 mmol / g.

[0016] According to some embodiments, the ratio of the acid amount of weak acid to medium strong acid in the catalyst is 10:1 - 2:1; for example, it is 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1.

[0017] According to some embodiments, the ratio of the acid amount of weak acid to medium strong acid in the catalyst is 7:1 - 2.5:1.

[0018] According to some embodiments, the ratio of the acid amount of weak acid to medium strong acid in the catalyst is 7:1 - 4:1.

[0019] According to some embodiments, the silica - alumina ratio of the Y zeolite is 2.0 - 7.5; for example, it is 2.0, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7. According to some embodiments, the silica - alumina ratio of the Y zeolite is 3 - 6.

[0020] The de - olefination reaction belongs to the carbocation reaction mechanism. The surface acid amount and acid strength of the catalyst have an important influence on this reaction. Its weak acid center is the main active center of the reaction, and the strong acid center plays an auxiliary role. Therefore, the proportional relationship between strong acid and weak acid also has a certain influence on the reaction behavior. The acidity of the zeolite mainly comes from the trivalent aluminum atoms and aluminum ions (AlO) on the framework and in the pores + , the higher the silica - alumina ratio, the fewer the weak acid sites, and the lower the silica - alumina ratio, the easier the zeolite framework collapses. The purpose of adding the mixed acid during the forming process is to adjust the silica - alumina ratio of the zeolite framework, and then adjust the framework strength and acid distribution of the zeolite. On the other hand, the introduction of the sulfated oxide of the transition metal can increase more acid sites and improve the total acid amount. The Y zeolite with a silica - alumina ratio within this range is selected in the present invention, so that the total acid amount and active sites of the final zeolite - type catalyst are in a suitable range.

[0021] According to some embodiments, the mass ratio of the sulfated oxide of the transition metal to the mass of the Y zeolite is (0.02 - 0.2):1; for example, it is 0.05:1, 0.07:1, 0.09:1, 0.11:1, 0.13:1, 0.15:1, 0.17:1, 0.19:1.

[0022] According to some embodiments, the mass ratio of the sulfated oxide of the transition metal to the mass of the Y zeolite is 0.02:1 to 0.05:1.

[0023] According to some embodiments, the sulfated oxide of the transition metal is selected from one or more of sulfated zirconia, sulfated molybdenum oxide, or sulfated titanium oxide.

[0024] According to some embodiments, the catalyst further comprises a binder.

[0025] According to some embodiments, the binder is selected from one or more of γ-alumina with a specific surface area greater than 250 m 2 / g, silica sol, aluminum sol, titanium sol, and santo powder.

[0026] According to some embodiments, the mass ratio of the Y zeolite to the binder is 1:(0.5 - 2.0), for example, 1:0.5, 1:0.7, 1:0.9, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2.0.

[0027] In a second aspect, the present application provides a method for preparing a molecular sieve-type catalyst, comprising the following steps:

[0028] (1) Shaping a mixed powder containing Y zeolite raw powder, transition metal salt, and optionally a binder with an acid solution to obtain a catalyst precursor, wherein the acid solution contains sulfuric acid;

[0029] (2) Drying and calcining the catalyst precursor to obtain the molecular sieve-type catalyst.

[0030] According to some embodiments, the preparation method comprises:

[0031] (1) Stirring and mixing the powder components including Y zeolite raw powder, transition metal salt, binder, and additive at room temperature;

[0032] (2) Uniformly injecting the acid solution into the powder obtained in step (1), and kneading in a blender to form a homogeneous semi-solid state without dry powder, and the acid solution includes sulfuric acid;

[0033] (3) Extruding the catalyst precursor kneaded in step (2) and sending it to an oven for drying with air blowing;

[0034] (4) High-temperature calcining the catalyst dried and shaped in step (3) to obtain the molecular sieve-type catalyst.

[0035] According to some embodiments, the acid solution further contains other protonic acids.

[0036] According to some embodiments, the other protonic acid is selected from one or more of hydrochloric acid, nitric acid, acetic acid, methanesulfonic acid, chlorosulfonic acid, or fluorosulfonic acid.

[0037] According to some embodiments, the molar ratio of the sulfuric acid to the other protonic acid is 1:(0.1 - 1.5), such as 1:0.1, 1:0.5, 1:0.7, 1:1, 1:1.2, 1:1.4.

[0038] According to some embodiments, the molar ratio of the sulfuric acid to the other protonic acid is 1:(0.8 - 1.2).

[0039] According to some embodiments, the molar ratio of the sulfuric acid to the other protonic acid is 1:1.

[0040] According to some embodiments, the concentration of the acid solution is 0.5 - 10 wt%, such as 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%.

[0041] According to some embodiments, the concentration of the acid solution is 1 - 8 wt%.

[0042] According to some embodiments, the concentration of sulfuric acid in the acid solution is not less than 0.3 wt%, such as 1 wt%, 4 wt%, 4.5 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%.

[0043] According to some embodiments, the concentration of sulfuric acid in the acid solution is 4 - 8 wt%.

[0044] According to some embodiments, the mass ratio of the acid solution to the as - synthesized Y zeolite powder is (0.5 - 3):1, such as 0.5:1, 0.7:1, 0.9:1, 1.1:1, 1.3:1, 1.5:1, 1.7:1, 1.9:1, 2.1:1, 2.3:1, 2.5:1, 2.7:1, 2.9:1.

[0045] According to some embodiments, the transition metal salt is selected from one or more of zirconium salts, molybdates, or titanates.

[0046] According to some embodiments, the zirconium salt is selected from one or more of zirconium nitrate pentahydrate, zirconium tetrachloride, or zirconyl chloride.

[0047] According to some embodiments, the molybdate is selected from one or more of ammonium molybdate, magnesium molybdate, barium molybdate, or bismuth molybdate.

[0048] According to some embodiments, the titanate is selected from one or more of titanium tetrachloride, titanium sulfate, or titanyl sulfate.

[0049] According to some embodiments, the mass ratio of the transition metal salt to the Y zeolite base powder is (0.05 - 0.2):1; for example, 0.05:1, 0.07:1, 0.09:1, 0.11:1, 0.13:1, 0.15:1, 0.17:1, 0.19:1.

[0050] According to some embodiments, the binder is selected from one or more of γ-alumina with a specific surface area greater than 250 m 2 / g, silica sol, aluminum sol, titanium sol, and shengfeng powder.

[0051] According to some embodiments, the mass ratio of the zeolite base powder to the binder is 1:(0.5 - 2.0), for example, 1:0.5, 1:0.7, 1:0.9, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2.

[0052] According to some embodiments, the mixed powder further includes an additive.

[0053] According to some embodiments, the additive is selected from one or more of bentonite, silica sol, shengfeng powder, or hydroxypropyl cellulose.

[0054] According to some embodiments, the mass ratio of the Y zeolite base powder to the additive is 1:(0.015 - 0.03), for example, 1:0.015, 1:0.018, 1:0.02, 1:0.022, 1:0.025, 1:0.03.

[0055] According to some embodiments, in step (1), the temperature for forming is 15 - 60°C, for example, 15°C, 25°C, 35°C, 45°C, 55°C.

[0056] According to some embodiments, in step (1), the temperature for forming is 20 - 40°C.

[0057] According to some embodiments, in step (1), the time for forming is 2 - 4 h; for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h.

[0058] According to some embodiments, in step (2), the drying is carried out by blowing air or drying in an oven.

[0059] According to some embodiments, the blowing air drying is carried out in an air atmosphere or an inert gas atmosphere.

[0060] According to some embodiments, the drying temperature is 80 to 150 °C, such as 50 °C, 70 °C, 80 °C, 90 °C, 110 °C, 130 °C, 150 °C.

[0061] According to some embodiments, the drying time is 12 to 24 h; such as 12 h, 15 h, 18 h, 21 h, 24 h.

[0062] According to some embodiments, in step (2), the calcination is carried out in an air atmosphere.

[0063] According to some embodiments, the calcination temperature is 400 to 600 °C, such as 400 °C, 420 °C, 440 °C, 460 °C, 480 °C, 500 °C, 520 °C, 540 °C, 560 °C, 580 °C, 600 °C.

[0064] According to some embodiments, the calcination temperature is 500 to 600 °C.

[0065] According to some embodiments, the calcination time is 0.5 to 8 h, such as 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 6 h, 7 h, 8 h.

[0066] According to some embodiments, the calcination time is 2 to 5 h.

[0067] In a third aspect, the present application provides an application of the molecular sieve type catalyst described in the first aspect or the molecular sieve type catalyst prepared by the preparation method described in the second aspect in the aromatics dealkylation reaction.

[0068] In a fourth aspect, the present application provides a method for aromatics dealkylation, comprising: contacting an aromatics raw material with the molecular sieve type catalyst described in the first aspect of the present application or the molecular sieve type catalyst prepared by the preparation method described in the second aspect of the present application for reaction.

[0069] According to some embodiments, the reaction temperature is 140 to 250 °C, such as 150 °C, 170 °C, 190 °C, 210 °C, 230 °C.

[0070] According to some embodiments, the reaction pressure is 1 to 3 MPa, such as 1.5 MPa, 2 MPa, 2.5 MPa.

[0071] According to some embodiments, the liquid hourly space velocity of the aromatics raw material is 1 to 40 h -1 , such as 5 h -1 , 10 h -1 , 15 h -1 , 20 h -1 , 25 h -1 , 30 h-1 , 35 h -1 .

[0072] According to some embodiments, the liquid hourly space velocity by mass of the aromatic hydrocarbon feedstock is 3 - 40 h -1 .

[0073] According to some embodiments, the liquid hourly space velocity by mass of the aromatic hydrocarbon feedstock is 10 - 30 h -1 .

[0074] According to some embodiments, when used for olefin removal from aromatic hydrocarbons, it includes: contacting the aromatic hydrocarbon feedstock with the molecular sieve catalyst obtained by the preparation method of the present invention to carry out the olefin removal reaction. Among them, when applied to olefin removal from xylene, the feedstock mainly includes C8 mixed aromatic hydrocarbons (the mixed aromatic hydrocarbons mainly include xylene, ethylbenzene, styrene, etc.); when applied to olefin removal from reformate, the feedstock mainly includes 40 - 60 wt% of C8 mixed aromatic hydrocarbons (the mixed aromatic hydrocarbons mainly include xylene, ethylbenzene, styrene, etc.), and the balance is a mixture of non-aromatic hydrocarbons, benzene, toluene, C9 aromatic hydrocarbons, C 10 + aromatic hydrocarbons, etc.

[0075] In this application, the reaction temperature for olefin removal from aromatic hydrocarbons is 140°C - 250°C, the reaction pressure is 1.0 MPa - 3.0 MPa, and the liquid hourly space velocity by mass is 1 h -1 - 40 h -1 . In an industrial plant, the liquid hourly space velocity by mass for olefin removal from xylene is 4 h -1 - 10 h -1 , and usually the liquid hourly space velocity by mass for olefin removal from reformate is 1 h -1 - 2 h -1 . However, the catalyst of the present invention has high performance, and the liquid hourly space velocity by mass for olefin removal from reformate can be increased to 3 - 40 h -1 (such as 30 h -1 ).

[0076] The molecular sieve catalyst obtained by the present invention through loading solid superacid (sulfated oxides of transition metals) and mixed acid forming process has abundant acid active centers, the total acid amount and the amount of weak acid are significantly increased, and the acidic active sites are significantly increased. Moreover, by adjusting the molecular sieve cation composition and the silicon-aluminum ratio in the framework through acid solution forming to regulate the molecular sieve pore structure, the specific surface area of the catalyst is increased and the average pore diameter is increased, which not only improves the carbon-holding capacity of the catalyst, but also enables the catalyst to have good mechanical strength and stability, thereby improving the catalyst life and achieving a more efficient catalytic effect.

[0077] The molecular sieve catalyst of the present invention has good catalytic activity and olefin removal selectivity under high space velocity conditions. When applied to the olefin removal reaction, the increase in the acid center density of the molecular sieve catalyst prepared in the present invention is beneficial to accelerating the reaction rate, thereby increasing the reaction space velocity. The increase in space velocity can not only significantly inhibit the increase in toluene content caused by side reactions, but also inhibit the increase in bromine index, and greatly improve the catalytic olefin removal efficiency. That is, the catalyst prepared in the present invention has good catalytic activity and olefin removal selectivity under high space velocity conditions, and at the same time has good mechanical strength and stability, solving the problems of weak carbon tolerance and short single-pass life of molecular sieve catalysts in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is the ammonia-TPD diagram of Example 1, Comparative Example 1 and Comparative Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0079] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with examples and drawings. The specific examples described here are only used to explain the present invention and do not constitute any limitation to the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts of the present disclosure. Such structures and technologies are also described in many publications.

[0080] In order to investigate the performance of the catalyst in a short time, an accelerated deactivation method with high space velocity is adopted in the examples and comparative examples of the present invention.

[0081] The binder alumina used in the present invention is γ-alumina with a specific surface area greater than 250 m 2 / g.

[0082] The extrusion molding of the present invention is carried out at room temperature (about 15-30 °C), and the molding time is 30 min.

[0083] The test methods and equipment used in the present invention are as follows:

[0084] The pore structure in the present invention is tested by an adsorption instrument, and the BET test equipment model is: 3Flex Version 4.04; before testing the sample, desorption pretreatment is carried out first, the temperature is 300 °C, and the time is 24 hours.

[0085] In this invention, the ammonia-TPD was tested using the 33750000-18-FW1701-0100 from Tianjin Pengxiang Technology Co., Ltd.; the test conditions for ammonia-TPD were as follows: the catalyst loading was 3 g, and the adsorption temperature was 100 - 600 °C. By performing peak deconvolution using Gaussian distribution, the acid amount corresponding to the desorption temperature of 250 - 400 °C was considered as the acid amount of medium-strong acid; the acid amount corresponding to the desorption temperature of 150 - 250 °C was considered as the acid amount of weak acid.

[0086] In this invention, the bromine value was tested using a bromine valence meter, and the model of the bromine valence meter used was: Metrohm 852 Titrando; the test conditions for the bromine value included: (1) Electrolyte: 260 mL of methanol and 140 mL of 3 mol / L potassium bromide solution were added to 600 mL of glacial acetic acid at one time; (2) Potassium bromide solution: 178 g of potassium bromide was dissolved in 500 mL of distilled water; (3) Cyclohexene standard solution: Approximately 0.12 g of cyclohexene was accurately weighed using a 0.25 mL syringe with a needle on an analytical balance accurate to one ten-thousandth, and dissolved in 50 g of benzene.

[0087] Example 1

[0088] 100 g-moles of Y zeolite powder with a silica-alumina ratio of 3.6, 50 g of binder alumina, and 10 g of zirconium nitrate pentahydrate were prepared. After mixing the above powders evenly, a mixed powder 1 was obtained. A mixed acid 2 was prepared by mixing 5 wt% sulfuric acid and 5 wt% nitric acid in a 1:1 molar ratio to obtain 150 mL of the mixed acid. The mixed acid 2 was uniformly injected into the continuously stirred mixed powder 1 until a homogeneous semi-solid state without dry powder was achieved, extruded into pellets, dried at 80 °C, and then calcined at 550 °C for 5 h to obtain the catalyst.

[0089] The pore structure data of the catalyst are shown in Table 1. After loading sulfated zirconia and treatment with the mixed acid, the increase in the average pore diameter and total pore volume of the zeolite can effectively inhibit the coking deactivation of the catalyst.

[0090] The total acid amount was measured by acid amount titration (using piperidine as a masking agent, phenolphthalein as a color indicator, and potassium hydrogen phthalate as a calibration substance), and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0091] 5 g of the above catalyst was used for the non-hydrogenative dealkylation test of reforming oil in a fixed-bed reactor. The raw material was a mixture of benzene and diisopropylbenzene, and the bromine index was 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 . Using the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst deactivated after reacting for 195 hours. The dealkylation data of the catalyst are shown in Table 4.

[0092] Figure 1 The results of ammonia-TPD can reflect the acid distribution. From Figure 1It can be seen that, compared with Comparative Example 1 and Comparative Example 4, the total acid amount and the weak acid amount in the catalyst of the present invention increase, and the ratio of strong acid to weak acid changes.

[0093] Example 2

[0094] The catalyst synthesis steps of Example 2 are the same as those of Example 1.

[0095] Take 5 g of the catalyst in Example 1 and conduct a non-hydrogenation dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 10.0 h -1 . Taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 530 hours.

[0096] Example 3

[0097] The difference in the catalyst synthesis steps from Example 1 is that the acid addition conditions are changed to sulfuric acid with a content of 5.0 wt%, hydrochloric acid with a content of 5.0 wt%, and acetic acid with a content of 5.0 wt%. The specific steps include:

[0098] Prepare 100 gram-moles of Y zeolite raw powder with a silica-alumina ratio of 3.6, 10 grams of zirconium nitrate pentahydrate, and 50 grams of binder alumina. After mixing the above powders evenly, a mixed powder 1 is obtained. Mix 5.0 wt% sulfuric acid, 5.0 wt% hydrochloric acid, and 5.0 wt% acetic acid in a molar ratio of 1:0.5:0.5 to obtain 150 mL of mixed acid 2. Inject the mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude it into a shape, dry it at 80 °C, and then calcine it at 550 °C for 5 h to obtain the catalyst. The pore structure data is shown in Table 1.

[0099] The total acid amount is measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0100] Take 5 g of the above catalyst and conduct a non-hydrogenation dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 190 hours. The dealkylation data of the catalyst is shown in Table 4.

[0101] Example 4

[0102] The difference in the catalyst synthesis steps from Example 1 is that the acid addition conditions are changed to sulfuric acid with a content of 12 wt% and nitric acid with a content of 12 wt%. The specific steps include:

[0103] Prepare 100 molar of Y zeolite powder with a silica-alumina ratio of 3.6, 10 grams of zirconium nitrate pentahydrate and 50 grams of binder alumina. After mixing the above powders evenly, obtain mixed powder 1. Mix 12wt% hydrochloric acid and 12wt% nitric acid in a 1:1 molar ratio to obtain 150 mL of mixed acid 2. Inject mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude into strips, dry at 80 °C, and then calcine at 550 °C for 5 h to obtain the catalyst. Its pore structure data is shown in Table 1.

[0104] The total amount of acid is measured by acid titration, and the results are shown in Table 2. The bromine value of the reactants is shown in Table 3.

[0105] Take 5 g of the above catalyst and carry out the non-hydrogenation dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 193 hours. The dealkylation data of the catalyst is shown in Table 4.

[0106] Example 5

[0107] The difference in the catalyst synthesis steps from Example 1 is that the acid addition condition is changed to 2wt% sulfuric acid and 2wt% nitric acid. The specific steps include:

[0108] Prepare 100 molar of Y zeolite powder with a silica-alumina ratio of 3.6, 10 grams of zirconium nitrate pentahydrate and 50 grams of binder alumina. After mixing the above powders evenly, obtain mixed powder 1. Mix 2wt% sulfuric acid and 2wt% nitric acid in a 1:1 molar ratio to obtain 150 mL of mixed acid 2. Inject mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude into strips, dry at 80 °C, and then calcine at 550 °C for 5 h to obtain the catalyst. Its pore structure data is shown in Table 1.

[0109] The total amount of acid is measured by acid titration, and the results are shown in Table 2. The bromine value of the reactants is shown in Table 3.

[0110] Take 5 g of the above catalyst and carry out the non-hydrogenation dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 175 hours. The dealkylation data of the catalyst is shown in Table 4.

[0111] Example 6

[0112] Different from Example 1, the molar ratio of nitric acid to sulfuric acid in the mixed acid was changed. The specific steps were as follows:

[0113] 100 gram-moles of Y zeolite powder with a silica-alumina ratio of 3.6, 10 grams of zirconium nitrate pentahydrate, and 50 grams of binder alumina were prepared. After mixing the above powders evenly, a mixed powder 1 was obtained. Sulfuric acid with an acid concentration of 5 wt% and nitric acid with an acid concentration of 5 wt% were mixed at a molar ratio of 1:0.5 to obtain 150 mL of mixed acid 2. The mixed acid 2 was evenly injected into the continuously stirred mixed powder 1 until a homogeneous semi-solid state without dry powder was achieved, extruded into strips, dried at 80 °C, and then calcined at 550 °C for 5 h to obtain a catalyst. The pore structure data are shown in Table 1.

[0114] The total acid amount was measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactants is shown in Table 3.

[0115] 5 g of the above catalyst was used for the non-hydrogenation de-olefination test of reforming oil in a fixed-bed reactor. The raw material was a mixture of benzene and diisopropylbenzene, and the bromine index was 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst was deactivated after reacting for 199 hours. The de-olefination data of the catalyst are shown in Table 4.

[0116] Example 7

[0117] Different from Example 1, the addition amount of zirconium nitrate pentahydrate was changed to 5 grams. The specific steps were as follows:

[0118] 100 gram-moles of Y zeolite powder with a silica-alumina ratio of 3.6, 5 grams of zirconium nitrate pentahydrate, and 50 grams of binder alumina were prepared. After mixing the above powders evenly, a mixed powder 1 was obtained. Sulfuric acid with a concentration of 5 wt% and nitric acid with a concentration of 5 wt% were mixed at a molar ratio of 1:1 to obtain 150 mL of mixed acid 2. The mixed acid 2 was evenly injected into the continuously stirred mixed powder 1 until a homogeneous semi-solid state without dry powder was achieved, extruded into strips, dried at 80 °C, and then calcined at 550 °C for 5 h to obtain a catalyst. The pore structure data are shown in Table 1.

[0119] The total acid amount was measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactants is shown in Table 3.

[0120] 5 g of the above catalyst was used for the non-hydrogenation de-olefination test of reforming oil in a fixed-bed reactor. The raw material was a mixture of benzene and diisopropylbenzene, and the bromine index was 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard. The de-olefination data of the catalyst are shown in Table 4.

[0121] Example 8

[0122] Different from Example 1, the silica-alumina ratio of the Y zeolite is 5.5, and the specific steps include:

[0123] Prepare 100 g of Y zeolite powder with a silica-alumina ratio of 5.5, 10 g of zirconium nitrate pentahydrate and 50 g of binder alumina. After mixing the above powders evenly, mixed powder 1 is obtained. Mix 5 wt% sulfuric acid and 5 wt% nitric acid in a molar ratio of 1:1 to obtain 150 mL of mixed acid 2. Inject mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude it into pellets, dry at 80 °C, and then calcine at 550 °C for 5 h to obtain the catalyst. The pore structure data is shown in Table 1.

[0124] The total acid amount is measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0125] Since this example uses a Y zeolite with a silica-alumina ratio of 5.5, the acid amount and weak acid amount of this zeolite itself are relatively low. After treatment with superacid and mixed acid, the total acid amount and weak acid amount are increased.

[0126] Take 5 g of the above catalyst and conduct a non-hydrogenation de-olefination test on reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , with the outlet bromine index of 200 mgBr / 100 g of oil as the standard. The de-olefination data of the catalyst is shown in Table 4.

[0127] Example 9

[0128] Different from Example 1, bentonite is selected as the additive, and the acid addition condition is changed to 5 wt% sulfuric acid and 5 wt% methanesulfonic acid. The specific steps include:

[0129] Prepare 100 g of Y zeolite powder with a molecular silica-alumina ratio of 3.6, 10 g of zirconium nitrate pentahydrate, 47.5 g of binder alumina and 2.5 g of bentonite. After mixing the above powders evenly, mixed powder 1 is obtained. Mix 5 wt% sulfuric acid and 5 wt% methanesulfonic acid in a molar ratio of 1:1 to obtain 150 mL of mixed acid 2. Inject mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude it into pellets, dry at 80 °C, and then calcine at 550 °C for 5 h to obtain the catalyst. The pore structure data is shown in Table 1.

[0130] The total acid amount is measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0131] Take 5 g of the above catalyst and conduct a non-hydrogenative dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , and taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 191 hours. The dealkylation data of the catalyst are shown in Table 4.

[0132] Example 10

[0133] Differing from Example 1, the dosage of the mixed acid is 250 mL, and the specific steps include:

[0134] Prepare 100 gram-moles of Y molecular sieve raw powder with a silica-alumina ratio of 3.6, 50 grams of binder alumina, and 10 grams of zirconium nitrate pentahydrate. After mixing the above powders evenly, a mixed powder 1 is obtained. Mix 5 wt% sulfuric acid and 5 wt% nitric acid in a molar ratio of 1:1 to obtain 250 mL of mixed acid 2. Inject the mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude it into pellets, dry it at 80 °C, and then calcine it at 550 °C for 5 h to obtain the catalyst.

[0135] The pore structure data of the catalyst are shown in Table 1. The total acid amount is measured by acid amount titration (using piperidine as a masking agent, phenolphthalein as a color indicator, and potassium hydrogen phthalate as a calibrator), and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0136] Take 5 g of the above catalyst and conduct a non-hydrogenative dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , and taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 200 hours. The dealkylation data of the catalyst are shown in Table 4.

[0137] Comparative Example 1

[0138] Differing from Example 1 in the catalyst synthesis steps, the mixed acid solution only contains sulfuric acid. The specific steps include:

[0139] Prepare 100 gram-moles of Y molecular sieve raw powder with a silica-alumina ratio of 3.6, 10 grams of zirconium nitrate pentahydrate, and 50 grams of binder alumina. After mixing the above powders evenly, a mixed powder 1 is obtained. Add 150 mL of 5.0 wt% sulfuric acid to the mixed powder, inject the sulfuric acid evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude it into pellets, dry it at 80 °C, and then calcine it at 550 °C for 5 h to obtain the catalyst, and its pore structure data are shown in Table 1.

[0140] The total acid amount was measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0141] Take 5 g of the above catalyst and conduct a non-hydrogenative deolefination test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst was deactivated after reacting for 161 hours. The deolefination data of the catalyst are shown in Table 4.

[0142] Comparative Example 2

[0143] The difference in the catalyst synthesis steps from Example 1 is that zirconium nitrate pentahydrate is not added. The specific steps include:

[0144] Prepare 100 gram-moles of Y molecular sieve raw powder with a silica-alumina ratio of 3.6 and 50 grams of binder alumina. After mixing the above powders evenly, mixed powder 1 is obtained. Mix 5 wt% sulfuric acid and 5.0 wt% nitric acid in a molar ratio of 1:1 to obtain 150 mL of mixed acid 2. Inject mixed acid 2 evenly into the continuously stirred mixed powder 1 until it becomes a homogeneous semi-solid state without dry powder, extrude it into shape, dry it at 80 °C, and then calcine it at 550 °C for 5 h to obtain the catalyst. The pore structure data are shown in Table 1.

[0145] The total acid amount was measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0146] Take 5 g of the above catalyst and conduct a non-hydrogenative deolefination test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst was deactivated after reacting for 156 hours. The deolefination data of the catalyst are shown in Table 4.

[0147] Comparative Example 3

[0148] The catalyst synthesis steps of Comparative Example 3 are the same as those of Comparative Example 2.

[0149] Take 5 g of the catalyst in Comparative Example 2 and conduct a non-hydrogenative deolefination test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 10.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst was deactivated after reacting for 217 hours. The deolefination data of the catalyst are shown in Table 4.

[0150] Comparative Example 4

[0151] The difference between the catalyst synthesis steps and Example 1 is that in Comparative Example 4, the mixed acid solution is not added. The specific steps include:

[0152] Prepare 100 gram-moles of Y zeolite raw powder with a silica-alumina ratio of 3.6, 10 grams of zirconium nitrate pentahydrate and 50 grams of binder alumina. After mixing the above powders evenly, a mixed powder is obtained. Add 150 mL of deionized water to the mixed powder, stir evenly, extrude into pellets, dry at 80 °C, and then calcine at 550 °C for 5 h to obtain the catalyst. The pore structure data is shown in Table 1.

[0153] The total acid amount is measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0154] Take 5 g of the above catalyst to carry out the non-hydrogenation dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 80 hours. The dealkylation data of the catalyst is shown in Table 4.

[0155] Comparative Example 5

[0156] The difference between the catalyst synthesis steps and Example 1 is that the mixed acid is 5 wt% acetic acid and 5 wt% nitric acid. The specific steps include:

[0157] Prepare 100 gram-moles of Y zeolite raw powder with a silica-alumina ratio of 3.6, 50 grams of binder alumina and 10 grams of zirconium nitrate pentahydrate. After mixing the above powders evenly, a mixed powder 1 is obtained. Mix 5 wt% nitric acid and 5 wt% acetic acid in a molar ratio of 1:1 to obtain 150 mL of mixed acid 2. Inject the mixed acid 2 evenly into the continuously stirred mixed powder 1 until a homogeneous semi-solid state without dry powder is obtained, extrude into pellets, dry at 80 °C, and then calcine at 550 °C for 5 h to obtain the Y-sz1 catalyst.

[0158] The pore structure data of the catalyst is shown in Table 1. The total acid amount is measured by acid amount titration, and the results are shown in Table 2. The bromine value of the reactant is shown in Table 3.

[0159] Take 5 g of the above catalyst to carry out the non-hydrogenation dealkylation test of reforming oil in a fixed-bed reactor. The raw material is a mixture of benzene and diisopropylbenzene, and the bromine index is 1000 mgBr / 100 g of oil. Reaction pressure: 2.0 MPa, temperature: 210 °C, space velocity: 30.0 h -1 , taking the outlet bromine index of 200 mgBr / 100 g of oil as the standard, the catalyst is deactivated after reacting for 140 hours. The dealkylation data of the catalyst is shown in Table 4.

[0160] Table 1

[0161]

[0162]

[0163] The carbon tolerance and lifespan of the catalyst are related to the pore structure. The pore distribution can refer to the BET results, as shown in Table 1. It can be seen from Table 1 that the catalyst of the present invention introduces sulfated zirconia by the method of mixed acid forming, which can effectively increase the specific surface area of the Y zeolite catalyst. At the same time, the expansion of the pore diameter is also beneficial to avoid the phenomenon of catalyst coking deactivation. Compared with the forming method using a single protonic acid, the advantage of introducing sulfated zirconia by mixed acid forming is that under the same acid concentration and addition amount, the mixed acid forming obtains a more advantageous pore structure and specific surface area.

[0164] Table 2

[0165]

[0166]

[0167] Table 3

[0168]

[0169]

[0170] The bromine value can directly reflect the content of unsaturated olefins in the product. The smaller the bromine value, the higher the efficiency of olefin removal. When the bromine value exceeds 200, it can be considered that the catalyst is deactivated.

[0171] Table 4

[0172]

[0173]

[0174] Among them, the conversion rate is the conversion rate of benzene in the raw material.

[0175] The lifespan of the present invention is the total running time when the bromine index of the product at the outlet exceeds 200.

[0176] It can be seen from Table 3 and Table 4 that the stability and service life of the catalyst of the present invention are improved.

[0177] In summary, the present invention utilizes the characteristics of large pore diameter and pore volume of Y zeolite itself, and introduces sulfated oxides of transition metals by adding transition metal salts (especially zirconium salts) to Y zeolite and adopting a one-step forming method with mixed acids, thereby increasing the total acid amount and weak acid amount of the catalyst. Compared with the zeolite without mixed acid treatment, the surface acid active sites of the catalyst of the present invention increase, the distribution of strong and weak acids is appropriate, and the ratio is optimized, thus effectively inhibiting side reactions and improving the catalytic de-olefin efficiency. At the same time, after the mixed acid treatment, the specific surface area of the catalyst increases and the average pore diameter increases, improving the adsorption capacity and carbon-holding capacity of the catalyst, and further improving the catalyst life.

[0178] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A molecular sieve type catalyst, comprising a Y molecular sieve and a sulfated oxide of a transition metal.

2. The molecular sieve type catalyst according to claim 1, wherein The specific surface area of the catalyst is 200 to 1000 m 2 / g, preferably 300 to 500 m 2 / g; and / or, the average pore diameter of the catalyst is 0.5 - 15 nm, preferably 0.7 - 10 nm; and / or, the total acid amount in the catalyst is greater than 1.0 mmol / g, preferably 1.05 - 2 mmol / g; and / or, the ratio of the acid amount of weak acid and medium strong acid in the catalyst is 10:1 - 2:1, preferably 7:1 - 2.5:1; and / or, the silica-alumina ratio of the Y molecular sieve is 2.0 - 7.5, preferably 3 - 6; and / or, the mass ratio of the sulfated oxide of the transition metal to the mass of the Y molecular sieve is (0.02 - 0.2):1, preferably 0.02:1 - 0.05:

1.

3. The molecular sieve type catalyst according to claim 1, characterized in that, The sulfated oxide of the transition metal is selected from one or more of sulfated zirconia, sulfated molybdenum oxide, or sulfated titanium oxide; and / or, the catalyst further comprises a binder. Preferably, the binder is selected from one or more of γ-alumina with a specific surface area greater than 250 m 2 / g, silica sol, aluminum sol, titanium sol, and sesbania powder; preferably, the mass ratio of the Y zeolite to the binder is 1:(0.5 - 2.0).

4. A preparation method of a molecular sieve type catalyst, comprising the following steps: (1) Form a catalyst precursor by shaping a mixed powder containing Y zeolite raw powder, transition metal salt and an optional binder with an acid solution, wherein, The acid solution contains sulfuric acid; (2) Drying and calcining the catalyst precursor to obtain the molecular sieve type catalyst.

5. The preparation method according to claim 4, characterized in that, The acid solution further contains other proton acids. Preferably, the other proton acids are selected from one or more of hydrochloric acid, nitric acid, acetic acid, methanesulfonic acid, chlorosulfonic acid or fluorosulfonic acid; preferably, the molar ratio of the sulfuric acid to the other proton acids is 1:(0.1 - 1.5), preferably 1:(0.8 - 1.2); and / or, the concentration of the acid solution is 0.5 - 10 wt%, preferably 1 - 8 wt%; Preferably, the concentration of sulfuric acid in the acid solution is not less than 0.3 wt%, preferably 4 - 8 wt%; and / or, the mass ratio of the acid solution to the raw powder of the Y molecular sieve is (0.5 - 3):

1.

6. The preparation method according to claim 4 or 5, characterized in that The transition metal salt is selected from one or more of zirconium salts, molybdates or titanates. Preferably, the zirconium salt is selected from one or more of zirconium nitrate pentahydrate, zirconium tetrachloride or zirconium oxychloride; and / or, the molybdate is selected from one or more of ammonium molybdate, magnesium molybdate, barium molybdate or bismuth molybdate; and / or, the titanate is selected from one or more of titanium tetrachloride, titanium sulfate or titanium oxysulfate; preferably, the mass ratio of the transition metal salt to the raw powder of the Y molecular sieve is (0.05 - 0.2):1; and / or, The binder is selected from one or more of γ-alumina with a specific surface area greater than 250 m 2 / g, silica sol, aluminum sol, titanium sol, and sesbania powder; preferably, the mass ratio of the Y-zeolite raw powder to the binder is 1:(0.5-2.0).

7. The preparation method according to any one of claims 4-6, characterized in that, The mixed powder further includes an additive; preferably, the additive is selected from one or more of bentonite, silica sol, sesbania powder or hydroxypropyl cellulose; and / or, the mass ratio of the raw powder of the molecular sieve and the additive is 1:(0.015 - 0.03).

8. The preparation method according to any one of claims 4-7, characterized in that, In step (1), the forming temperature is 15 - 60 °C, preferably 20 - 40 °C; the forming time is 2 - 4 h; and / or, In step (2), the drying is air drying or drying in an oven. Preferably, the air drying is carried out in an air atmosphere or an inert gas atmosphere; preferably, the drying temperature is 80 - 150 °C, and / or, the drying time is 12 - 24 h; and / or, the calcining is carried out in an air atmosphere; preferably, the calcining temperature is 400 - 600 °C, preferably 500 - 600 °C; and / or, The roasting time is 0.5 to 8 h, preferably 2 to 5 h.

9. Use of the molecular sieve type catalyst according to any one of claims 1-3 or the molecular sieve type catalyst prepared by the preparation method according to any one of claims 4 to 8 in the aromatics dealkylation reaction.

10. A method for removing olefins from aromatic hydrocarbons, comprising: Contact the aromatic hydrocarbon raw material with the molecular sieve type catalyst according to any one of claims 1-3 or the molecular sieve type catalyst prepared by the preparation method according to any one of claims 4 to 8 for reaction; Preferably, the reaction temperature is 140 to 250 °C, the reaction pressure is 1 to 3 MPa, and the mass hourly space velocity is 1 to 40 h -1 .

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