A microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst and its preparation method and application

Abstract

The invention discloses a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst and a preparation method and application thereof. The invention prepares a molecular sieve solid acid catalyst with suitable surface acidity and pore structure, and applies the catalyst to the catalytic synthesis of long-chain alkyl aromatic hydrocarbons. The catalyst of the invention has the characteristics of good activity stability, high conversion rate, high selectivity, high product linearity and low energy consumption.

Description

Technical Field

[0001] The invention relates to a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst and a preparation method thereof, as well as application in the alkylation reaction of long-chain olefins and aromatic hydrocarbons to synthesize long-chain alkyl aromatic hydrocarbons. Background Art

[0002] Long-chain alkyl aromatics can be used as intermediates for detergents and surfactants for oil displacement, as well as synthetic lubricants and heat transfer oils. They can also be used to produce lubricant additives and corrosion inhibitors. They are important petrochemical raw materials and products. Long-chain olefins produced by processes such as liquid wax dehydrogenation, paraffin cracking, Fischer-Tropsch synthesis, and ethylene polymerization are used as alkylating agents. Long-chain alkyl aromatics are produced by carrying out long-chain alkylation reactions of aromatics such as benzene, toluene, ethylbenzene, xylene, methylethylbenzene, propylbenzene, and diethylbenzene under the action of acid catalysts. At present, hydrofluoric acid or aluminum trichloride catalysts are mainly used in industry to carry out alkylation reactions of long-chain olefins and aromatics to synthesize long-chain alkyl aromatics. These catalysts have problems such as corrosion of equipment, environmental pollution, and difficulty in separation from reaction products. The development of solid acid catalysts and their catalytic reaction processes is an effective way to solve these problems.

[0003] A lot of research has been conducted at home and abroad on solid acid catalysts and catalytic reaction processes for the alkylation of long-chain aromatics, and some research progress has been made. Patent CN 1092755A discloses a method for synthesizing linear alkylbenzenes using a fluorinated silicon-aluminum catalyst by Universal Oil Products Company. Under liquid phase reaction conditions of a temperature of 80 to 140°C and a molar ratio of benzene to linear olefins of 5:1 to 30:1, C6 to C 20 The linear olefins alkylate benzene, the olefin conversion rate is above 98%, the alkylbenzene selectivity is above 85%, the linearity of alkylbenzene is above 90%, and the catalyst activity stability time is 48h. Patent CN 1100401A discloses an improved method for the alkylation of aromatics and linear olefins of Universal Oil Products Company. It is believed that the aromatic byproducts formed in the process of dehydrogenation of normal alkanes to generate linear olefins significantly reduce the activity stability of the alkylation solid acid catalyst; although the dehydrogenation and selective hydrogenation materials are treated to remove aromatic byproducts, the activity stability of the alkylation solid acid catalyst has been improved, but the developed solid acid alkylation Detal process is still a catalyst that undergoes 24 hours of reaction and regeneration and frequent switching operations. Patent CN1210509A discloses a method for Hutzman Petroleum Company to synthesize linear alkylbenzenes using a fluorine-containing mordenite catalyst. The olefin used contains 10 to 14 carbon atoms, and the benzene alkylation reaction can be carried out by reactive distillation. Patent CN 1222134A discloses a two-step method for the alkylation of benzene to generate linear alkylbenzenes, containing benzene and C5 to C 30The olefin reaction fluid first contacts the fluorine-containing mordenite and then contacts the fluorine-containing clay. Patent CN1169889A discloses the metal ion exchange and acid-treated HY type molecular sieve catalyst used by Dalian Chemical Industry. The catalyst is heated at a temperature of 120-300°C, a pressure of 1.0-5.0 MPa, and a weight space velocity of 1-20 h -1 , benzene olefin molar ratio 0.5 ~ 25:1 reaction conditions, by C 10 ~C 14 The alkylation of straight-chain olefins with benzene to produce linear alkylbenzenes, and a catalyst regeneration method of washing with benzene and alkanes is mentioned. Patent CN1277894A discloses the use of a supported heteropolyacid catalyst at a temperature of 100-300°C, a pressure of 1.0-5.0 MPa, and a weight space velocity of 0.5-30 h -1 , benzene olefin molar ratio of 1 to 30:1, reaction time of 10 to 48h, a method for synthesizing linear alkylbenzene. Patent CN 1327970A discloses a liquid phase alkylation method of benzene and olefin of Tsinghua University, the catalyst is composed of mordenite or ZSM-20 or β zeolite, 0.1 to 5% (mass fraction) of fluorine or phosphorus, γ-Al2O3, and benzene is used as a solvent for catalyst washing and regeneration. Patent CN 1560001A discloses a method of Dalian University of Technology for producing long-chain alkylbenzene from long-chain olefins and benzene, using γ-Al2O3 with mesoporous and macroporous double pore structure as a carrier to prepare AlCl3 immobilized catalyst, reacting at a temperature of 0 to 300°C, a pressure of 0.5 to 5.0 MPa, a molar ratio of benzene to long-chain olefin of 2 to 20:1, and a volume ratio of catalyst to raw material of 0.05 to 0.5, the long-chain olefin can be C6 ＝ ~C 20 ＝ ; Benzene and 1-C 12 ＝ The catalyst undergoes 5 intermittent reactions after 8 hours of reaction, and the catalyst activity remains unchanged. Patent CN 1657161A discloses a solid acid catalyst for the alkylation of linear olefins and benzene to produce linear alkylbenzene from Nanjing University of Technology. The catalyst is composed of a composite oxide of 0.005-0.1% by mass of alkali metal or / and alkaline earth metal oxide, 5-25% of WO3 and the balance of ZrO2, and the deactivated catalyst is regenerated by washing with hot benzene. Under intermittent reaction conditions of 85°C, the catalyst undergoes 6 repeated reactions of reaction and regeneration, and the catalyst performance deteriorates slightly. These intermittent alkylation reaction methods are not easy to achieve large-scale continuous production, and it is difficult to evaluate the activity stability of solid acid catalysts.

[0004] At present, the outstanding problem of solid acid catalysts for synthesizing long-chain alkyl aromatics is the poor activity stability. Improving the activity stability of solid acid catalysts through optimizing the design of solid acid catalysts and optimizing the alkylation reaction conditions is the development direction of developing solid acid catalytic synthesis technology for long-chain alkyl aromatics. Summary of the invention

[0005] The present invention prepares a molecular sieve solid acid catalyst with suitable surface acidity and pore structure, and applies it to the catalytic synthesis of long-chain alkyl aromatics. The synthesis method has the characteristics of being environmentally friendly, having good catalyst activity stability, high conversion rate, high selectivity, high product linearity and low energy consumption.

[0006] During the solid acid catalytic reaction of long-chain olefins and aromatic hydrocarbons alkylation, a coking side reaction occurs, and the generated coke is deposited on the catalyst surface, resulting in the coking and deactivation of the solid acid catalyst. The present invention uses an organic amine template and a hexadecyl trimethyl ammonium bromide or hexadecyl trimethyl ammonium chloride template at the same time, and prepares a microporous / mesoporous composite SAPO-5 molecular sieve catalyst with strong surface acidity through hydrothermal synthesis, improves the intrapore diffusion of the reaction raw materials and products, increases the alkylation reaction opportunity of long-chain olefins and aromatic hydrocarbons, thereby inhibiting olefin polymerization, reducing the coking rate, inhibiting the coking and deactivation of the catalyst, and improving the activity stability of the catalyst. The catalyst bed loaded into the reactor is pretreated by hot nitrogen purge to remove part of the moisture adsorbed by the catalyst and replace the air in the reactor, so that the catalyst has better catalytic performance. The feed sequence of first inputting aromatic hydrocarbons and filling the reactor, and then inputting the alkylation mixed raw materials into the reactor is adopted, so that the initial alkylation reaction is carried out under the condition of a higher aromatic hydrocarbon to olefin molar ratio, reducing the chance of olefin polymerization under the condition of high catalyst activity in the initial reaction, reducing the coking and deactivation rate of the catalyst in the initial reaction, and improving the activity stability of the catalyst. According to the principle of like dissolves like, long-chain alkyl aromatics or long-chain alkane solvents are added to the reaction raw materials to dilute the long-chain olefins and reduce the contact opportunities between the long-chain olefin molecules, thereby inhibiting the olefin polymerization reaction, reducing the coking rate, and improving the activity stability of the catalyst. Part of the effluent from the alkylation reactor is recycled as one of the feeds to the reactor, which mainly contains the remaining aromatics, long-chain alkyl aromatics and / or long-chain alkanes. The remaining aromatics are mainly used to ensure the molar ratio of aromatics to long-chain olefins in the alkylation reactor feed, while the other feed to the reactor is fresh feed or total feed, and its molar ratio of aromatics to long-chain olefins can be less than 10:1, or even close to the stoichiometric molar ratio of 1:1, which reduces the input amount of aromatics to the reactor and reduces the load of the distillation separation system, which is beneficial to energy saving. By optimizing the reaction conditions of aromatics and long-chain olefins alkylation that match the performance of the microporous / mesoporous composite SAPO-5 molecular sieve catalyst, the catalyst activity stability, long-chain alkyl aromatics selectivity and product linearity are improved.

[0007] The technical solution of the present invention is as follows:

[0008] A microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst is prepared by the following method:

[0009] According to the molar ratio of Al2O3:P2O5:SiO2:H2O = 1.0:0.5~1.5:0.2~1.5:40~60, the aluminum source, phosphorus source and deionized water are stirred and mixed for 0.5~5h, and then the silicon source is added while stirring, and the stirring is mixed for 0.5~5h, and then the template R1 is added dropwise while stirring until the pH of the mixed system is 5.5~6.5, and the stirring is continued for 0.5~5h, and then the mixture is stirred according to the molar ratio of Al2O3:template R2 = 1.0:0.02 ~0.10 molar ratio, add template R2 while stirring, continue stirring for 0.5~5h, then place at 150~200℃ for crystallization for 8~72h, filter, wash with water, dry (90~120℃, 5~24h), then heat from 5~40℃ to 500~600℃ at a heating rate of 0.5~10℃ / min, and calcine at a constant temperature for 1~8h, after crushing, obtain microporous / mesoporous composite SAPO-5 molecular sieve, and obtain molded catalyst after extrusion molding;

[0010] in,

[0011] The aluminum source is aluminum oxide monohydrate;

[0012] The phosphorus source is phosphoric acid;

[0013] The silicon source is tetraethyl orthosilicate;

[0014] The template agent R1 is one of tri-n-propylamine, triethylamine, triethanolamine, and diethanolamine, or a mixture of two or more in any proportion;

[0015] The template R2 is one of cetyltrimethylammonium chloride (CTAC) and cetyltrimethylammonium bromide (CTAB) or a mixture of the two in any proportion; preferably, the template R2 is fed in the form of an ethanol solution with a mass fraction of 5 to 20% of the template R2;

[0016] Silica sol can be used as a binder to form the catalyst. The catalyst can be formed by tableting, ball rolling, or spray drying. Specifically, the extrusion molding method is as follows:

[0017] According to the mass ratio of microporous / mesoporous composite SAPO-5 molecular sieve to alumina monohydrate of 0.1 to 1.8:1, and the ratio of sesbania powder to the total mass of molecular sieve and alumina monohydrate of 0.02 to 0.08:1, the molecular sieve, alumina monohydrate and sesbania powder are mixed for 5 to 30 minutes to obtain a solid mixture, 0.2 to 1.0 times the mass of deionized water is added to the solid mixture, and the mixture is stirred for 5 to 30 minutes; and a dilute nitric acid aqueous solution with a mass fraction of 5 to 10% is added dropwise while stirring, and the dilute nitric acid is The amount of aqueous solution added is sufficient to ensure that the mixture can be kneaded into a mud ball and extruded into strips; the strips are allowed to stand at 5-40°C for 4-24 hours and dried at 90-120°C for 5-24 hours; then the temperature is raised from 5-40°C to 500-600°C at a heating rate of 0.5-10°C / min, and the strips are calcined at a constant temperature for 1-10 hours to obtain a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst with a mass fraction of 10-70% of the microporous / mesoporous composite SAPO-5 molecular sieve, and the remainder is Al2O3.

[0018] The microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst of the present invention can be applied to the synthesis of long-chain alkyl aromatic hydrocarbons. The specific application method is:

[0019] First, the raw aromatics are fed into the fixed bed alkylation reactor to fill the reactor; then the raw aromatics and raw C6~C 24 The mixture of long-chain olefins and additives is fed into a fixed bed reactor and contacts with a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst at a temperature of 100-300°C, a pressure of 0.2-10.0 MPa, and a total mass space velocity of 0.1-20.0 h -1 , the ratio of the amount of aromatic hydrocarbon to the long-chain olefin substance is 2 to 50:1, and the ratio of the amount of the additive to the long-chain olefin substance is 0 to 20:1, and the alkylation reaction of aromatic hydrocarbon and long-chain olefin is carried out under liquid phase reaction conditions to generate a product long-chain alkyl aromatic hydrocarbon;

[0020] A portion of the effluent from the alkylation reactor is used as a circulating fluid to be circulated to the reactor, and another portion is used as an effluent fluid to be separated from the excess feedstock and products (aromatic hydrocarbons, long-chain alkyl aromatic hydrocarbons, etc.) by a distillation separation system, and a circulation ratio of the volume flow rate of the circulating fluid to the effluent fluid is 0 to 80;

[0021] After the catalyst is deactivated, it is burned and regenerated for recycling;

[0022] In the above method,

[0023] The aromatic hydrocarbon is one or a mixture of any proportion of benzene, toluene, ethylbenzene, xylene, methylethylbenzene, propylbenzene, and diethylbenzene;

[0024] C6~C 24The long-chain olefins are preferably obtained by liquid wax dehydrogenation, paraffin cracking, Fischer-Tropsch synthesis, ethylene polymerization, and propylene polymerization;

[0025] The additive is a long-chain alkyl aromatic solvent or a long-chain alkane solvent; the long-chain alkyl aromatic solvent is selected from C6~C 24 One or a mixture of any proportion of long-chain alkyl benzene, toluene, ethylbenzene, xylene, methylethylbenzene, propylbenzene, diethylbenzene; the long-chain alkane solvent is selected from C6 to C 24 One or a mixture of two or more of the long chain alkanes in any proportion, preferably C 10 ~C 13 Liquid wax.

[0026] Preferably, after the microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst is loaded into the reactor, it is first heated at a temperature of 50 to 500°C, a pressure of 0.1 to 5.0 MPa, and a nitrogen flow rate to catalyst mass ratio of 0.01 to 0.1 m 3 / (h﹒g) for 0.5 to 24h nitrogen purge pretreatment.

[0027] Preferably, the alkylation reaction conditions are: temperature 150-280°C, pressure 0.5-8.0 MPa, total mass space velocity of feed 0.2-5.0 h -1 , the ratio of the amount of aromatic hydrocarbons to long-chain olefins is 5 to 30:1, the ratio of the amount of additives to long-chain olefins is 1 to 10:1, and the circulation ratio of the circulating fluid of the alkylation reactor to the volume flow rate of the effluent fluid to the distillation separation system is 1 to 50.

[0028] Furthermore, in the operation of two reactors in series, when the olefin content of the effluent of the second reactor exceeds the standard, or the total olefin conversion rate is not greater than 98%, the second reactor is switched to the first reactor; when the olefin content of the effluent of the first reactor exceeds the standard, such as the olefin conversion rate of the first reactor is not greater than 30%, the catalyst in the first reactor is regenerated. The regeneration method can be nitrogen or water vapor purging, oxygen-containing gas or air charring, or nitrogen or water vapor purging, polar solvent washing, oxygen-containing gas or air charring. The operating conditions of the second alkylation reactor can be the same as those of the first reactor, or different.

[0029] The aromatic hydrocarbons, long-chain olefins, additive long-chain alkyl aromatic solvents or long-chain alkane solvents can also be input into the alkylation reactor for reaction after adsorption refining. They can be adsorbed and refined individually or their mixture can be adsorbed and refined. The adsorption refining conditions are: adsorption temperature 0-280°C, pressure 0.1-10MPa, mass space velocity 0.2-20h -1, continuous adsorption time is 10 to 2000 hours; the adsorbent is one of the following or a mixture thereof: 5A molecular sieve, 13X molecular sieve, HY molecular sieve, USY molecular sieve, activated clay, activated alumina, WO3 / Al2O3, WO3-ZrO2 / Al2O3, P / Al2O3, F / Al2O3, porous silica gel, activated carbon, phosphorus aluminum molecular sieve or phosphorus aluminum molecular sieve composition containing substituted elements, SBA-15 molecular sieve or loaded modified SBA-15 molecular sieve, MCM-41 molecular sieve or loaded modified MCM-41 molecular sieve, Hβ molecular sieve, H-Moderite molecular sieve, HZSM-20 molecular sieve or loaded modified HZSM-20 molecular sieve.

[0030] Since long-chain olefin raw materials often contain trace amounts of long-chain dienes, long-chain olefins and long-chain dienes undergo alkylation reactions with aromatic hydrocarbons at the same time to generate long-chain alkyl aromatic hydrocarbons and trace amounts of aromatic-based long-chain olefins. Due to the pore size limitation of the microporous / mesoporous composite SAPO-5 molecular sieve catalyst, it is difficult for aromatic-based olefin impurities to further alkylate with aromatic hydrocarbons, resulting in trace amounts of aromatic-based olefin impurities in the alkylation product, causing the bromine index of the product to be higher and the stability to be biased.

[0031] In order to promote the further alkylation of aromatic olefin impurities and aromatic hydrocarbons and improve the olefin conversion rate, a microporous / mesoporous composite SAPO-5 molecular sieve catalyst was used as the alkylation catalyst in the first reactor, and a solid acid catalyst with a larger pore size was used as the alkylation catalyst in the second reactor. The following two alkylation reactors were operated in series:

[0032] The effluent from the first alkylation reactor catalyzed by the microporous / mesoporous composite SAPO-5 molecular sieve catalyst is fed into the second reactor and contacted with a solid acid catalyst with a larger pore size at a temperature of 100-300°C, a pressure of 0.2-10.0 MPa, and a total mass space velocity of 0.1-20.0 h -1 Under liquid phase reaction conditions within a range, a second reactor is used for alkylation catalytic reaction;

[0033] The solid acid catalyst with a larger pore size is selected from activated clay, fluorine-containing clay, mesoporous WO3 / ZrO2 composite oxide solid acid catalyst, and one or a mixture of any two or more of aluminum oxide, silicon dioxide, and montmorillonite loaded with acidic compounds. The acidic compound is one of the following or a mixture of any two or more of them: ZrO2, WO3, sulfuric acid, phosphoric acid, hydrofluoric acid, ammonium fluoride, phosphotungstic heteropolyacid, silicotungstic heteropolyacid, phosphomolybdic heteropolyacid, phosphotungstic heteropolyacid calcine, silicotungstic heteropolyacid calcine, phosphomolybdic heteropolyacid calcine, boric acid, aluminum chloride, zinc chloride, ferric chloride, copper chloride, and chromium chloride. The total mass fraction of the loaded mass of the acidic compound is 0.1 to 50%. The operating conditions of the second alkylation reactor can be the same as or different from those of the first reactor.

[0034] If the olefin conversion rate decreases significantly with the extension of the reaction time, or the olefin conversion rate requirement cannot be met, the alkylation reaction temperature can be increased, or the space velocity can be reduced, or the catalyst can be regenerated. The regeneration method is to stop feeding the long-chain olefins in the reaction raw materials, continue to feed aromatic hydrocarbons, or feed a mixture of aromatic hydrocarbons and an additive long-chain alkane solvent or a long-chain alkyl aromatic solvent, and wash and regenerate the catalyst under the operating conditions of a temperature of 10°C to 400°C and a pressure of 0.1 to 15 MPa, and the regeneration time is 2 to 1000 hours.

[0035] In addition, the deactivated alkylation catalyst can be regenerated by burning it using the following burning regeneration process:

[0036] After the alkylation reaction feed is stopped, nitrogen is first introduced into the reactor, and the ratio of nitrogen flow rate to catalyst mass is 0.01-0.5m 3 / (h﹒g), nitrogen purge for 1 to 24 hours to complete the nitrogen purge operation; then, input air, the ratio of air flow to catalyst mass is 0.05 to 0.25m 3 / (h﹒g), with a heating rate of 0.2~5.0℃ / min, the air char regeneration is raised from the initial temperature of 100~400℃ to the end temperature of 450~650℃, and the final temperature is constant for 1.0~24.0h; finally, nitrogen is input, and the ratio of nitrogen flow rate to catalyst mass is 0.01~0.5m 3 / (h﹒g), reduce the reactor catalyst bed temperature from the final charring temperature to the alkylation reaction temperature, and continue nitrogen purging for 1 to 24 hours to complete the catalyst charring regeneration operation. It is also possible to adopt a programmed charring regeneration process of several temperature stages from low temperature to high temperature. It is also possible to perform off-site charring regeneration of the deactivated alkylation catalyst.

[0037] The alkylation reactor may be a fixed bed, a moving bed, an expanded bed, a fluidized bed, a stirred tank reactor, and a catalytic distillation reactor. The reactor may have one or more feed ports, and the aromatic hydrocarbons, long-chain olefins, and / or long-chain alkane solvents, and / or long-chain alkyl aromatic solvents, and / or circulating fluids may be mixed and fed into the alkylation reactor, or may be fed into the reactor separately. The alkylation reaction unit may have multiple reactors operated in parallel or in series, and each reactor may be loaded with the same or different alkylation catalysts; the reaction operating conditions of each reactor may be the same or different; the reactor may adopt an upper end feeding method or a lower end feeding method.

[0038] The effluent from the alkylation reactor or the long-chain alkyl aromatic fraction obtained by distillation and separation can be hydrotreated to remove trace olefin impurities, reduce the bromine index of the synthesized long-chain alkyl aromatics, and improve the stability and subsequent processing performance of the product. The hydrotreatment process is as follows:

[0039] A fixed bed hydrogenation reaction device with upper feeding is used, wherein hydrogen is first fed into the reactor to fill it, and then hydrogen, alkylation reactor effluent or long-chain alkyl aromatic hydrocarbon fraction obtained by distillation separation thereof are fed. The reaction fluid contacts with a supported hydrogenation catalyst at a temperature of 50°C to 350°C, a pressure of 0.5 to 10.0 MPa, and a mass space velocity of 0.2 to 20 h -1 , hydrogen-to-oil volume ratio of 200 to 5000, and the trace olefin impurities in the hydrogenation raw material are removed. The metal active component of the supported hydrogenation catalyst is selected from one or a mixture of two or more of metal Pd, Pt, and Ni in any proportion, and the carrier is one or a mixture of two or more of porous alumina, silicon oxide, activated carbon, 5A molecular sieve, 13X molecular sieve, SBA-15 molecular sieve, and MCM-41 molecular sieve in any proportion, and the mass fraction of the metal active component is 0.1 to 10%. The hydrogenation reaction device can be a trickle bed reaction device or a slurry bed reaction device.

[0040] The beneficial effects of the present invention are mainly reflected in:

[0041] (1) The catalyst used is a non-corrosive, environmentally friendly solid acid catalyst;

[0042] (2) The alkylation catalyst has good activity stability, with a stable continuous reaction time of more than 2,000 hours, a long-chain olefin conversion rate of more than 98%, a long-chain alkyl aromatics selectivity of more than 97%, and good catalyst coke regeneration performance; the device has a long stable operation time, which can avoid frequent switching operations between reactor reaction and regeneration;

[0043] (3) The long-chain alkyl aromatics product has good quality, with a linearity higher than 97% and a bromine index below 10 mgBr / 100 g;

[0044] (4) The reactor can be operated in a cycle, which not only maintains the alkylation reaction at a certain molar ratio of aromatics to long-chain olefins, but also reduces the operating load of the distillation separation system, thus saving investment and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the XRD spectrum of the sample prepared in step (1) of Example 1.

[0046] Figure 2 N2- adsorption / desorption isotherm curve of the sample prepared in step (1) of Example 1.

[0047] Figure 3 This is the BJH pore size distribution diagram calculated by the BJH method for the sample prepared in step (1) of Example 1. DETAILED DESCRIPTION

[0048] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0049] The chemical reagents and reaction raw materials used in the embodiment include: alumina monohydrate, Al2O3 mass fraction 70%, Shandong Aluminum Group Corporation; phosphoric acid (molar mass = 98.0g / mol, ≧85%, analytically pure), Shanghai Lingfeng Chemical Reagent Co., Ltd.; ethyl orthosilicate (molar mass = 208.33g / mol, SiO2 mass content of 28%, analytically pure), Shanghai Aladdin Biochemical Technology Co., Ltd.; tri-n-propylamine (molar mass = 143.27g / mol, ≧98%, chemically pure), Shanghai Aladdin Biochemical Technology Co., Ltd.; triethylamine (molar mass = 101.0g / mol, ≧99%, analytically pure), Shanghai Aladdin Biochemical Technology Co., Ltd.; triethanolamine (molar mass = 149.19g / mol, analytically pure), Shanghai Aladdin Biochemical Technology Co., Ltd.; diethanolamine (molar mass = 105.14 g / mol, ≧99%, analytical grade), Shanghai Aladdin Biochemical Technology Co., Ltd.; hexadecyltrimethylammonium chloride (molar mass = 328.42 g / mol, ≧97%), Shanghai Aladdin Biochemical Technology Co., Ltd.; hexadecyltrimethylammonium bromide (molar mass = 364.45 g / mol, ≧90%), Shanghai Aladdin Biochemical Technology Co., Ltd.; nitric acid, analytical grade, Zhejiang Zhongxing Chemical Reagent Co., Ltd.; sesbania powder, 99%, Jiangsu Prat Bioengineering Co., Ltd.; benzene, industrial grade, Fushun Petrochemical Company; toluene, analytical grade, ≥99.5%, Sinopharm Chemical Reagent Co., Ltd.; xylene, analytical grade, ≥99.0%, Sinopharm Chemical Reagent Co., Ltd.; ethylbenzene, analytical grade, ≥98.5%, Sinopharm Chemical Reagent Co., Ltd.; C 16 ~C 18 Long chain olefins, C 16 Olefins and C18 The mass fractions of olefins are 54% and 44% respectively, SIGMA Corporation, USA; C 10 ~C 13 Liquid wax, industrial grade, Fushun Petrochemical Company; C 10 ~C 13 Linear alkylbenzene (LAB), industrial grade, Fushun Petrochemical Company; n-dodecane, analytical grade, 98%, Aladdin Reagent Company; n-hexene, 97%, ACROS Reagent Company, USA; n-dodecene, ≥90%, Fluka Reagent Company; C 10 ~C 13 Long-chain olefins, industrial grade, Fushun Petrochemical Company; quartz sand, analytical grade, Sinopharm Chemical Reagent Co., Ltd.; high-purity hydrogen, 99.99%, Hangzhou Jingong Gas Company; high-purity nitrogen, 99.99%, Hangzhou Jingong Gas Company. All chemical reagents and reaction raw materials were not purified before use.

[0050] Alkylation reaction experimental apparatus, product analysis method and data processing method:

[0051] The alkylation reaction experiment of aromatics and long-chain olefins was carried out in a fixed bed reactor. The reactor was made of a stainless steel tube with an inner diameter of 10 mm, an outer diameter of 14 mm, and a length of 100 cm. A thermocouple protection sleeve (outer diameter 3 mm) was installed in the reactor to measure the temperature of the catalyst bed at different heights. The catalyst was loaded in the constant temperature zone in the middle of the reaction tube. The upper and lower ends of the reaction tube were filled with quartz sand, and the catalyst was separated from the quartz sand by quartz wool. The reaction tube, quartz wool and quartz sand were inert to the alkylation reaction. The reaction temperature was controlled by a temperature control instrument and displayed by a temperature display instrument. The reaction pressure was adjusted by a nitrogen pressure reducing valve. The reaction raw materials were injected from the lower end of the reactor by a double plunger metering pump, and the feed amount of the raw materials was weighed by an electronic balance. The reaction raw materials flowed through the catalyst bed to undergo alkylation reaction. The reaction products flowed out from the upper end of the reactor and entered the product receiving tank, and then were sampled and analyzed with a sampling bottle.

[0052] The bromine index of the alkylation feedstock and product was measured using an RPP-200Br bromine index tester produced by Taizhou Zhonghuan Analytical Instrument Co., Ltd. The olefin conversion rate (X) was obtained by dividing the difference between the bromine index of the feedstock and the product by the bromine index of the feedstock.

[0053] The composition of the alkylation product was analyzed using a 7890B gas chromatograph produced by Agilent Technologies Shanghai Analytical Instrument Co., Ltd. The chromatographic conditions were as follows: the chromatographic column was a 50m×Φ0.32mm×0.52μm DB-1 capillary column, the detector was a FID (hydrogen flame) detector, the carrier gas was high-purity nitrogen, the auxiliary gas was air, the fuel gas was hydrogen, the injector temperature was 250°C, the detector temperature was 300°C, and the column temperature program was 80°C for 1 min, then increased to 260°C at a rate of 15°C / min, and maintained at this temperature for 17 min.

[0054] Long-chain olefins and aromatics mainly undergo alkylation reactions to generate long-chain alkyl aromatics (LAA). Due to the isomerization of the double bond position of long-chain olefins and the shape-selective effect of molecular sieve catalysts, the generated long-chain alkyl aromatics include 2-position long-chain alkyl aromatics (2-LAA), 3-position long-chain alkyl aromatics (3-LAA), etc.; long-chain olefins (LO) undergo cracking side reactions to generate short-chain olefins (SO), and short-chain olefins and aromatics alkylate to generate short-chain alkyl aromatics (SAA). Assume that all types of olefin molecules have the same chromatographic correction factor, f1 = 0.5530; all types of alkyl aromatic molecules have the same correction factor, f2 = 1.0452. The reaction selectivity of long-chain alkyl aromatic products relative to the conversion of raw olefins (i.e., long-chain alkyl aromatic selectivity) is:

[0055]

[0056] Long-chain olefin feedstocks may contain trace amounts of branched olefins, and in the alkylation reaction between long-chain olefins and aromatics, long-chain olefins may also undergo carbon chain isomerization to generate a small amount of branched olefins, which undergo alkylation reaction with aromatics to generate a small amount of branched alkyl aromatics (CAA). The mass fraction of straight-chain alkyl aromatics in long-chain alkyl aromatics is taken as the linearity (D) of long-chain alkyl aromatics, expressed as:

[0057]

[0058] In the above formula: A i or A j is the chromatographic peak area fraction of component i or j; M i or M j is the molar mass of component i or j.

[0059] During the continuous reaction under stable reaction conditions, the continuous reaction time when the olefin conversion rate is lower than 98% is defined as the continuous stable reaction time or catalyst activity stable time (t S ).

[0060] Example 1: Preparation of microporous / mesoporous composite SAPO-5 molecular sieve

[0061] (1) Preparation of molecular sieves using different templates

[0062] Tri-n-propylamine, triethylamine, triethanolamine and diethanolamine were used as template R1 respectively, and hexadecyltrimethylammonium chloride was used as template R2. According to the molar ratio of Al2O3:P2O5:SiO2:H2O=1.0:1.0:0.4:45, alumina monohydrate, phosphoric acid and deionized water were first stirred and mixed for 2 hours to obtain mixture A; ethyl orthosilicate was added to mixture A while stirring, and stirred and mixed for 1 hour to obtain mixture B; organic amine template R1 was added dropwise to mixture B while stirring until the pH of the mixture reached 6.0, and stirring was continued for 1 hour to obtain mixture C; and according to the molar ratio of Al2O3:R2=1.0:0.05, a 15% ethanol solution of template R2 was added to mixture C while stirring, and stirring was continued for 1 hour to obtain mixture D. The mixture D was charged into a stainless steel reactor and crystallized at 180°C for 24 hours. Then, the crystallized product was cooled, filtered, washed with water, filtered four times, and dried at 120°C for 8 hours. Finally, the temperature was raised from 30°C to 600°C at a heating rate of 5°C / min and calcined at a constant temperature for 4 hours. After crushing, four microporous / mesoporous composite SAPO-5 molecular sieve samples were obtained, which were marked as Z1, Z2, Z3, and Z4 respectively.

[0063] The X'Pert PRO X-ray diffractometer produced by PNAlytical of the Netherlands was used for characterization. The XRD spectra of the four samples are shown in Figure 1 ,Depend on Figure 1 It can be seen that the diffraction peak shapes of samples synthesized by different templates remain consistent. These four samples are all SAPO-5 molecular sieves, which have an AFI-type skeleton structure and a microporous structure with a pore diameter of about 0.73 nm. The diffraction peak intensity of sample Z2 prepared by two templates, triethylamine and hexadecyltrimethylammonium chloride (CTAC), is higher, indicating that its crystallinity is higher.

[0064] The four samples were characterized by N2 adsorption / desorption and pore size distribution using a 3Flex S / N810 N2 adsorption instrument from McMerritt Instruments. Figure 2 is the N2- adsorption / desorption isotherm, Figure 3 is the BJH pore size distribution diagram calculated by the BJH method. Figure 2 It can be seen that these four SAPO-5 molecular sieve samples all have hysteresis loops, which represent the capillary condensation phenomenon in the mesopores, indicating that these molecular sieves contain mesoporous structures. Figure 3 The results show that all four SAPO-5 samples have a dual pore structure with micropores ≤2.0nm and mesopores ≥2.0nm. The BET specific surface areas of samples Z1, Z2, Z3, and Z4 are 326, 362, 352, and 338m, respectively.2 / g, and the total pore volumes are 0.367, 0.503, 0.436, and 0.453 cm 3 / g, and the average pore diameters are 4.505, 5.569, 4.958, and 5.371 nm, respectively. It can be seen that all four samples have microporous / mesoporous composite SAPO-5 molecular sieves with a dual-pore structure of micropores and mesopores, but the specific surface area, pore volume, and average pore diameter of the Z2 molecular sieve sample are larger.

[0065] (2) Preparation of molecular sieves using raw materials in different ratios

[0066] Using triethylamine as template R1 and cetyltrimethylammonium bromide (CTAB) as template R2, alumina monohydrate, phosphoric acid and deionized water were stirred and mixed for 3 hours according to the molar ratio of Al2O3:P2O5:SiO2:H2O=1.0:0.8:0.3:50 and the molar ratio of Al2O3:P2O5:SiO2:H2O=1.0:1.2:0.8:55, respectively, to obtain two mixtures A1 and A2; while stirring, ethyl orthosilicate was added to the mixtures A1 and A2, and stirred and mixed for 3 hours to obtain two mixtures B1 and B2 ; Add organic amine template R1 dropwise to mixtures B1 and B2 with stirring until the pH of the mixture reaches 5.5, and continue stirring for 4 hours to obtain two mixtures C1 and C2; then add a 10% ethanol solution of template R2 in a molar ratio of Al2O3:R2=1.0:0.03 to mixture C1 with stirring, and continue stirring for 3 hours to obtain mixture D1; then add a 20% ethanol solution of template R2 in a molar ratio of Al2O3:R2=1.0:0.08 to mixture C2 with stirring, and continue stirring for 3 hours to obtain mixture D2. The two mixtures of D1 and D2 were respectively placed in a stainless steel reactor and crystallized at 190°C for 48 hours; then, the crystallized product was cooled, filtered, washed with water, filtered for 3 times, and dried at 100°C for 24 hours; finally, the temperature was raised from 25°C to 540°C at a heating rate of 2°C / min, and calcined at a constant temperature for 8 hours. After crushing, two microporous / mesoporous composite SAPO-5 molecular sieve samples were obtained, marked as Z5 and Z6 respectively. After XRD, N2- adsorption / desorption and pore size distribution characterization, Z5 and Z6 samples are both microporous / mesoporous composite SAPO-5 molecular sieves with microporous and mesoporous dual pore structures.

[0067] (3) Preparation of molecular sieves under different crystallization conditions

[0068] The raw material ratio and preparation process are similar to those of the molecular sieve prepared in (1) above, and triethylamine is used as the template R1 and hexadecyltrimethylammonium chloride is used as the template R2 to obtain a mixture D. The mixture D is respectively loaded into two stainless steel reactors, and crystallized at 150°C for 72 hours and 170°C for 12 hours respectively; then, the crystallized product is cooled, filtered, washed with water, filtered 5 times, and dried at 110°C for 10 hours; finally, the temperature is programmed from 30°C to 540°C at a heating rate of 8°C / min, and the mixture is calcined at a constant temperature for 8 hours. After crushing, two microporous / mesoporous composite SAPO-5 molecular sieve samples are obtained, which are marked as Z7 and Z8 respectively. After XRD, N2- adsorption / desorption and pore size distribution characterization, the Z7 and Z8 samples are both microporous / mesoporous composite SAPO-5 molecular sieves with a dual pore structure of micropores and mesopores.

[0069] Example 2: Extrusion of microporous / mesoporous composite SAPO-5 molecular sieve catalyst

[0070] Using the Z1, Z2, Z3, and Z4 molecular sieve powders prepared in step (1) of Example 1, 40 g of molecular sieve powder, 24.5 g of alumina monohydrate, and 2.58 g of sesbania powder were stirred and mixed for 15 min to obtain a solid mixture in which the mass ratio of molecular sieve to alumina monohydrate was 1.63:1 and the ratio of sesbania powder to the total mass of molecular sieve and alumina monohydrate was 0.04:1; deionized water in a mass ratio of 0.8:1 to the solid mixture was added, and the mixture was stirred and mixed for 20 min; 75.5 mL of a 9.0% dilute nitric acid aqueous solution was added dropwise while stirring, and the mixture was kneaded. The mixture was formed into a mud ball and extruded into strips using a TBL-2 catalyst molding extrusion device produced by Tianjin University Beiyang Chemical Experimental Equipment Co., Ltd. The strips were allowed to stand at 30°C for 12 hours and dried at 100°C for 12 hours. The temperature was then raised from 30°C to 540°C in a Mabo furnace at a heating rate of 1°C / min and calcined at a constant temperature for 6 hours to obtain molded microporous / mesoporous composite SAPO-5 molecular sieve catalysts with a molecular sieve mass fraction of 70%, which were marked as CAT-1, CAT-2, CAT-3, and CAT-4, respectively, and the remainder of each molded catalyst was Al2O3.

[0071] Using the Z5 and Z6 molecular sieve powders prepared in step (2) of Example 1, 40 g of molecular sieve, 57.14 g of alumina monohydrate and 4.86 g of sesbania powder were stirred and mixed for 30 min to obtain a solid mixture in which the mass ratio of molecular sieve to alumina monohydrate was 0.7:1 and the ratio of sesbania powder to the total mass of molecular sieve and alumina monohydrate was 0.05:1. Deionized water in a mass ratio of 0.6:1 was added to the solid mixture and stirred for 10 min; then 103.0 mL of deionized water was added dropwise while stirring. A dilute nitric acid aqueous solution with a mass fraction of 6.0% is used to knead the mixture into a mud ball and extrude it into strips; the strips are allowed to stand at 20°C for 8 hours and dried at 120°C for 6 hours; then the temperature is raised from 20°C to 560°C in a Maboise furnace at a heating rate of 2°C / min and calcined at a constant temperature for 3 hours to obtain shaped microporous / mesoporous composite SAPO-5 molecular sieve catalysts with a molecular sieve mass fraction of 50%, which are marked as CAT-5 and CAT-6 respectively, and the remainder of each shaped catalyst is Al2O3.

[0072] Using the Z7 and Z8 molecular sieve powders prepared in step (3) of Example 1, 40 g of molecular sieve, 133.33 g of alumina monohydrate and 8.06 g of sesbania powder were stirred and mixed for 10 min to obtain a solid mixture in which the mass ratio of molecular sieve to alumina monohydrate was 0.3:1 and the ratio of sesbania powder to the total mass of molecular sieve and alumina monohydrate was 0.047:1. Deionized water in a mass ratio of 1.0:1 was added to the solid mixture and stirred for 20 min. Then, 176.0 g of deionized water was added dropwise while stirring. mL of a dilute nitric acid aqueous solution with a mass fraction of 7.0%, the mixture is kneaded into a mud ball and extruded into strips; the strips are allowed to stand at 30°C for 5 hours and dried at 90°C for 8 hours; then the temperature is raised from 20°C to 520°C in a Ma furnace at a heating rate of 1°C / min and calcined at a constant temperature for 10 hours to obtain a molded microporous / mesoporous composite SAPO-5 molecular sieve catalyst with a molecular sieve mass fraction of 30%, which are marked as CAT-7 and CAT-8 respectively, and the remainder of each molded catalyst is Al2O3.

[0073] Example 3: Preparation of palladium supported hydrogenation catalyst

[0074] 200 g of diaspore and 5 g of sesbania powder were mixed evenly, 150 g of distilled water was added while stirring, and the mixture was allowed to stand for 30 min to moisten. Then, 79.6 g of 5% nitric acid aqueous solution was added while stirring, and the mixture was kneaded into a mud ball, which was then extruded using a TBL-2 catalyst molding extrusion device; then, the mixture was allowed to stand at 25°C for 24 h, and the temperature was increased from 25°C to 550°C in a muffle furnace at a heating rate of 1.5°C / min, and the mixture was calcined at a constant temperature for 5 h; after crushing, 20-40 mesh Al2O3 particles were sieved and used as a catalyst carrier.

[0075] Weigh 10 g of 20-40 mesh Al2O3 catalyst carrier (with a specific surface area of ​​302 m 2 / g), an impregnation solution was prepared by mixing 0.648g of palladium nitrate dihydrate with 10g of distilled water, and the impregnation solution was added dropwise to the Al2O3 catalyst support while stirring, and allowed to stand for 24h; then, it was dried at 95°C for 3h, heated from 20°C to 550°C in a muffle furnace at a heating rate of 2°C / min, and calcined at a constant temperature for 4h to obtain a catalyst precursor. The catalyst precursor was obtained by reduction in the reactor tube at a pressure of 0.2MPa and a hydrogen volume space velocity of 500h -1 Under the conditions of , the temperature was raised from 20°C to 300°C at a rate of 2°C / min and reduced at constant temperature for 1h to obtain a supported catalyst with a mass fraction of palladium of 3%, recorded as Pd / Al2O3.

[0076] Examples 4-7: Evaluation of catalytic performance of microporous / mesoporous composite SAPO-5 molecular sieve catalyst

[0077] (1) Benzene and C 16 ~C 18 Catalytic Performance of Alkylation of Long-Chain Olefins

[0078] 4.0 g of the 20-40 mesh microporous / mesoporous composite SAPO-5 molecular sieve catalysts CAT-1-CAT-8 prepared in Example 2 were respectively loaded into the constant temperature zone in the middle of the fixed bed reactor, and the upper and lower ends of the reaction tube were filled with quartz sand, and the catalyst was separated from the quartz sand by quartz wool. At 150°C and a nitrogen flow rate to catalyst mass ratio of 0.03 m 3 / (h﹒g), the catalyst bed was pretreated with nitrogen purge for 2h. Benzene was introduced into the reactor at 50℃ to fill the reactor with benzene. At 250℃, 4.0MPa, and 1.0h mass space velocity, the reactor was heated to 100 ℃ and then heated to 200 ℃. -1 Under liquid phase reaction conditions, benzene: C 16 ~C 18 The reaction raw material with a long-chain olefin molar ratio of 20:1 was input into the reactor for continuous alkylation reaction, and the reactor effluent containing long-chain alkylbenzene (collectively referred to as long-chain alkyl aromatics) was obtained with the continuous reaction time of 100h and 1000h respectively. The bromine index of the effluent was measured and the gas chromatography composition was analyzed to obtain the reaction experimental results. The olefin conversion rate (X), long-chain alkyl aromatics selectivity (S) of the alkylation catalytic reaction of several molecular sieve catalysts were compared. LAA ) and the experimental results of the linearity (D) of long-chain alkyl aromatics are listed in Table 1 (Example 4).

[0079] Table 1 Benzene and C 16 ~C 18 Experimental results of alkylation of long-chain olefins

[0080]

[0081]

[0082] As can be seen from Table 1, 8 molecular sieve catalysts were used to react benzene with C 16 ~C 18 The alkylation reaction of long-chain olefins achieved good reaction results, with olefin conversion greater than 98%, long-chain alkylbenzene selectivity greater than 97%, long-chain alkylbenzene linearity greater than 97%, and the catalyst performance remained basically unchanged after 1000 hours of continuous alkylation reaction, indicating that these molecular sieve catalysts all have good catalytic performance for the alkylation of benzene and long-chain olefins, but the performance of CAT-2 catalyst is better.

[0083] (2) Toluene and C 16 ~C 18 Catalytic Performance of Alkylation of Long-Chain Olefins

[0084] In a similar manner to Example 4, at 400°C, a nitrogen flow rate to catalyst mass ratio of 0.2 m 3 / (h﹒g), the catalyst bed was pretreated with nitrogen purge for 1h. Toluene was introduced into the reactor at 20℃ to fill the reactor with toluene, and the reactor pressure was adjusted to 4.0MPa and the temperature was adjusted to 250℃. -1 Under the reaction conditions, toluene: C 16 ~C 18 A reaction raw material with a long-chain olefin molar ratio of 20:1 was input into a reactor for continuous alkylation reaction to obtain reactor effluents containing long-chain alkyltoluene (collectively referred to as long-chain alkyl aromatics) with continuous reaction times of 100 h and 1000 h, respectively. The bromine index of the effluent was measured and the gas chromatography composition was analyzed to obtain the reaction experimental results, which are listed in Table 2 (Example 5).

[0085] Table 2 Toluene and C 16 ~C 18 Experimental results of alkylation of long-chain olefins

[0086]

[0087] From Table 2, we can see that at a temperature of 250°C, a pressure of 4.0 MPa, and a mass space velocity of 1.0 h -1 , Raw material toluene: C 16 ~C 18 Under the liquid phase reaction conditions with a molar ratio of 20:1 for long-chain olefins, toluene and C 16 ~C 18The alkylation reaction of long-chain olefins achieved good reaction results, with olefin conversion greater than 98%, long-chain alkyltoluene selectivity greater than 97%, long-chain alkyltoluene linearity greater than 97%, and the catalyst performance remained basically unchanged after 1000 hours of continuous alkylation reaction, indicating that these molecular sieve catalysts all have good catalytic performance for the alkylation of toluene and long-chain olefins, but the performance of CAT-2 catalyst is better.

[0088] (3) Ethylbenzene and C 16 ~C 18 Catalytic Performance of Alkylation of Long-Chain Olefins

[0089] In a similar manner to Example 4, at 25°C, a nitrogen flow rate to catalyst mass ratio of 0.1 m 3 / (h﹒g), the catalyst bed was pretreated with nitrogen purge for 24h. Ethylbenzene was introduced into the reactor at 50℃ to fill the reactor with ethylbenzene. -1 Under the reaction conditions, ethylbenzene: C 16 ~C 18 A reaction raw material with a long-chain olefin molar ratio of 20:1 was input into a reactor for a continuous alkylation reaction to obtain reactor effluents containing long-chain alkyl ethylbenzene (collectively referred to as long-chain alkyl aromatics) with a continuous reaction time of 100 h and 1000 h, respectively. The bromine index of the effluent was measured and the gas chromatography composition was analyzed to obtain the reaction experimental results. The alkylation catalytic reaction results of several molecular sieve catalysts are listed in Table 3 (Example 6).

[0090] Table 3 Ethylbenzene and C 16 ~C 18 Experimental results of alkylation of long-chain olefins

[0091]

[0092] As can be seen from Table 3, the 8 molecular sieve catalysts were used to react ethylbenzene with C 16 ~C 18 The alkylation reaction of long-chain olefins achieved good reaction results, with olefin conversion greater than 98%, long-chain alkyl ethylbenzene selectivity greater than 97%, and long-chain alkyl ethylbenzene linearity greater than 97%. In addition, the catalyst performance remained basically unchanged after 1000 hours of continuous alkylation reaction, indicating that these molecular sieve catalysts all have good catalytic performance for the alkylation of ethylbenzene and long-chain olefins, but the performance of CAT-2 catalyst is better.

[0093] (4) Xylene and C 16 ~C 18 Catalytic Performance of Alkylation of Long-Chain Olefins

[0094] In a similar manner to Example 4, at 250°C, a nitrogen flow rate to catalyst mass ratio of 0.05 m 3 / (h﹒g), the catalyst bed was pretreated with nitrogen purge for 5h. Xylene was introduced into the reactor at 80℃ to fill the reactor with xylene. -1 Under liquid phase reaction conditions, xylene: C 16 ~C 18 A reaction raw material with a long-chain olefin molar ratio of 20:1 was input into a reactor for a continuous alkylation reaction to obtain reactor effluents containing long-chain alkylxylenes (collectively referred to as long-chain alkyl aromatics) with a continuous reaction time of 100 h and 1000 h, respectively. The bromine index of the effluent was measured and the gas chromatography composition was analyzed to obtain the reaction experimental results. The alkylation catalytic reaction results of several molecular sieve catalysts are listed in Table 4 (Example 7).

[0095] Table 4 Xylene and C 16 ~C 18 Experimental results of alkylation of long-chain olefins

[0096]

[0097] From Table 4, we know that the reaction of xylene and C using 8 molecular sieve catalysts 16 ~C 18 The alkylation reaction of long-chain olefins achieved good reaction results, with olefin conversion greater than 98%, long-chain alkylxylene selectivity greater than 97%, long-chain alkylxylene linearity greater than 97%, and the catalyst performance remained basically unchanged after 1000 hours of continuous alkylation reaction, indicating that these molecular sieve catalysts all have good catalytic performance for the alkylation of xylene and long-chain olefins, but the performance of CAT-2 catalyst is better.

[0098] Example 8: Investigation of Alkylation Reactor Effluent Recycling Ratio

[0099] The production of long-chain alkyl aromatics undergoes a catalytic reaction of aromatics and long-chain olefins for alkylation and a distillation separation process. In order to improve the olefin conversion rate, the selectivity of long-chain alkyl aromatics, and the stability of catalyst activity, it is required to use a reaction raw material with a high molar ratio of aromatics to long-chain olefins for liquid-phase alkylation reaction, and then separate the excess aromatics through a distillation process for recycling, and the separation energy consumption is relatively high. If the reactor effluent is divided into a circulating fluid that circulates to the reactor and an effluent fluid that goes to the separation system, the ratio of the volume flow of the circulating fluid to the effluent fluid is taken as the circulation ratio (R). A mixture of aromatics, long-chain olefins and a circulating fluid is used as the feed to the alkylation reactor. On the premise of meeting the requirements of the molar ratio of aromatics to long-chain olefins in the reactor feed (such as 20:1), the larger the value of the circulation ratio R, the smaller the required molar ratio of aromatics to long-chain olefins in the aromatics and long-chain olefins mixture, which can be below 10:1, which is conducive to reducing the load of aromatic distillation separation and reducing the energy consumption of the distillation separation process.

[0100] In a similar manner to Example 4, 4.0 g of the 20-40 mesh microporous / mesoporous composite SAPO-5 molecular sieve catalyst CAT-2 prepared in Example 2 was loaded into a fixed bed reactor. The reactor was heated at 150° C. and the ratio of nitrogen flow rate to catalyst mass was 0.05 m / s. 3 / (h﹒g), the catalyst bed was pretreated with nitrogen purge for 2h. Benzene was introduced into the reactor at 60℃ to fill the reactor with benzene. At 250℃, 4.0MPa, and 1.0h mass space velocity, the reactor was heated to 100 ℃ and then heated to 200 ℃. -1 Benzene: C 16 ~C 18 Under the liquid phase reaction conditions with a long-chain olefin molar ratio of 20:1, a mixture of benzene, long-chain olefin mixture and circulating fluid was used as feed to the alkylation reactor to carry out a continuous alkylation reaction. The catalytic reaction results under different circulation ratios R are listed in Table 5.

[0101] Table 5 Catalytic reaction results under different circulation ratios R

[0102] Circulation ratio R X，％ <![CDATA[S LAA ,%]]> D，％ <![CDATA[t S ,h]]> 0.0 98.76 98.38 97.26 2200 1.0 98.59 98.26 97.55 2300 5.0 98.63 98.32 97.29 2500 10.0 98.55 98.51 97.88 2600 50.0 98.57 98.47 97.63 2800

[0103] From Table 5, it is known that as the circulation ratio increases from 0.0 to 50.0, the olefin conversion rate, long-chain alkylbenzene selectivity, and the linearity of long-chain alkylbenzene do not change significantly, which are greater than 98%, 98%, and 97%, respectively. It is worth noting that as the circulation ratio increases, the catalyst activity stability time gradually prolongs, that is, the catalyst activity stability gradually improves. The reason is that the effluent of the alkylation reactor is circulated, and the reaction fluid at the catalyst bed height of different fixed bed reactors contains long-chain alkylbenzenes. According to the principle of like dissolves like, these long-chain alkylbenzenes dissolve and disperse the long-chain olefins, promote the mutual dissolution of long-chain olefins and aromatics, and reduce the chance of olefin polymerization side reactions, thereby inhibiting the coking deactivation of the solid acid catalyst surface and improving the catalyst activity stability. It can be seen that the circulation of the effluent of the alkylation reactor not only reduces the distillation separation load and reduces the separation energy consumption, but also helps to improve the catalyst activity stability.

[0104] Example 9: Investigation of dilution solvents for improving the activity and stability of alkylation catalysts

[0105] Using 4.0 g of the 20-40 mesh CAT-2 molecular sieve catalyst prepared in Example 2, a method similar to that in Example 4 was used to add n-dodecane, C 10 ~C 13 Liquid wax or C 10 ~C 13 Linear alkylbenzene (LAB, or long-chain alkylbenzene) diluent, at a temperature of 250°C, a pressure of 5.0 MPa, and a mass space velocity of 1.0 h -1 Under the liquid phase reaction conditions of 15:1 benzene to olefin molar ratio and 3:1 to 8:1 diluent to olefin molar ratio, alkylation reactions of benzene with n-hexene and benzene with n-dodecene were carried out respectively to investigate the effect of the diluent type on the catalyst activity and stability, and the experimental results are listed in Table 6. In addition, the linearity of the linear alkylbenzene in each reaction product was greater than 97%.

[0106] Table 6 Investigation results of the effects of dilution solvent type and dilution ratio on catalyst activity stability

[0107]

[0108] From the data in Table 6, it is known that as the molar ratio of the diluent solvent to the long-chain olefin increases, the reaction stability time gradually prolongs or the catalyst activity stability gradually improves. The reason is that increasing the molar ratio of the diluent solvent to the long-chain olefin reduces the olefin concentration in the reaction fluid, resulting in a decrease in the catalyst coking deactivation rate caused by olefin polymerization, which is beneficial to improving the activity stability of the catalyst. In addition, compared with the reaction results of adding normal alkanes (including n-dodecane, liquid wax) and LAB dilution solvents to the raw materials, the latter has a better stable reaction time or catalyst activity stability than the former. The reason may be that the LAB molecule has both long-chain alkyl and benzene rings, which not only dissolves and disperses long-chain olefins, but also promotes the mutual dissolution of benzene and olefins, reduces the chance of olefin polymerization, and inhibits the rate of coke formation; it also has a good dissolving effect on coke precursors, inhibits catalyst coking deactivation, and improves the catalyst activity stability. It can also be seen from Table 6 that the addition of n-dodecane, liquid wax or LAB dilution solvents to the raw materials has little effect on olefin conversion and alkylation selectivity.

[0109] Example 10: Investigation of the influence of alkylation reaction conditions

[0110] The main reaction conditions for the liquid phase alkylation of aromatics with long-chain olefins include temperature, mass space velocity, and molar ratio of aromatics to olefins. Using a method similar to Example 4, 4.0 g of the 20-40 mesh CAT-2 molecular sieve catalyst prepared in Example 2 was loaded into a fixed bed reactor and heated at 150°C and a nitrogen flow rate to catalyst mass ratio of 0.03 m / s. 3 / (h﹒g), the catalyst bed was pretreated with nitrogen purge for 2h. Benzene was introduced into the reactor at 50℃ to fill the reactor with benzene. C 10 ~C 13 Liquid wax dilution solvent, liquid wax and C 16 ~C 18 The molar ratio of long-chain olefins is 8:1. Under the liquid phase reaction conditions of 4.0 MPa pressure, the reaction mixture containing benzene, liquid wax, C 16 ~C 18 The reaction raw materials of long-chain olefins were input into the reactor for continuous alkylation reaction. The effects of reaction temperature, mass space velocity, and molar ratio of raw material benzene to olefins were investigated, and the reaction experimental results were obtained and listed in Table 7.

[0111] Table 7 Experimental results of investigating the influence of reaction conditions

[0112] Temperature, °C <![CDATA[Mass space velocity, h -1 > Benzene-olefin molar ratio X，％ <![CDATA[S LAA ,%]]> D，％ <![CDATA[t S ,h]]> 150 1.0 20 98.09 99.31 99.03 2113 180 1.0 20 98.16 99.25 98.79 2209 210 1.0 20 98.32 99.08 98.52 2257 230 1.0 20 98.47 98.92 98.06 2308 250 1.0 20 99.55 98.69 97.48 2650 280 1.0 20 99.63 98.38 97.15 2870 250 0.5 20 99.69 98.41 98.35 2713 250 3.0 20 99.28 98.72 97.42 2464 250 5.0 20 98.57 98.83 97.33 2216 250 1.0 5 98.56 98.15 97.18 2117 250 1.0 10 99.16 98.21 97.22 2315 250 1.0 30 99.58 98.73 98.13 3128

[0113] It can be seen from Table 7 that, with other reaction conditions unchanged, as the alkylation reaction temperature increases from 150°C to 280°C, the olefin conversion rate gradually increases, the catalyst activity stability time gradually prolongs, and the long-chain alkylbenzene selectivity and long-chain alkylbenzene linearity gradually decrease. Under the conditions of temperature of 250°C and benzene-olefin molar ratio of 20:1, as the mass space velocity increases, the olefin conversion rate, long-chain alkylbenzene linearity, and catalyst activity stability time gradually decrease, while the long-chain alkylbenzene selectivity gradually increases. In addition, at a temperature of 250°C and a mass space velocity of 1.0h -1 Under the condition of , as the molar ratio of raw benzene to olefin increases, the olefin conversion rate, long-chain alkylbenzene selectivity, long-chain alkylbenzene linearity and catalyst activity stability time all improve, but the unit capacity decreases and the separation energy consumption increases. In general, the better alkylation reaction conditions include temperature 250℃, mass space velocity 1.0h -1 , the molar ratio of raw material benzene to olefin is 20:1.

[0114] Example 11: Investigation of the regeneration conditions and regeneration performance of the alkylation catalyst after burning

[0115] Using 4.0 g of the 20-40 mesh CAT-2 molecular sieve catalyst prepared in Example 2, a method similar to that in Example 4 was used to add C 10 ~C 13 Liquid wax dilution solvent, liquid wax and C 16 ~C 18 The molar ratio of long-chain olefins is 8:1, at a temperature of 250°C, a pressure of 4.0 MPa, and a mass space velocity of 1.0 h -1 Benzene and C 16 ~C 18 Under the liquid phase reaction conditions with a molar ratio of long-chain olefins of 20:1, the alkylation reaction was continued. When the olefin conversion rate dropped to 85%, the input of the reaction raw materials was stopped. The input flow rate was 0.2m 3 / h of nitrogen, the ratio of nitrogen flow rate to catalyst mass is 0.05m 3 / (h﹒g), purged with nitrogen for 2h to obtain the coked deactivated catalyst.

[0116] The deactivated catalyst is regenerated by burning. The flow rate of the reactor containing the deactivated catalyst is 0.2-1.0 m 3 / h of air, the ratio of air flow to catalyst mass (R AIR / CAT ) is 0.05~0.25m 3 / (h﹒g), with a heating rate of 0.2~5.0℃ / min, the air charring regeneration is raised from the initial temperature of 100℃~400℃ to the final temperature of 480℃~650℃, and the final temperature is constant for 1.0~24.0h; finally, the input flow rate is 0.2m 3 / h of nitrogen, the ratio of nitrogen flow rate to catalyst mass is 0.05m 3 / (h﹒g), reduce the reactor catalyst bed temperature from the final charring temperature to 250℃, and continue nitrogen purging for 2h to complete the catalyst regeneration operation process. Using the regenerated catalyst, at a temperature of 250℃, a pressure of 4.0MPa, and a mass space velocity of 1.0h -1 Benzene and C 16 ~C 18 The molar ratio of long chain olefins is 20:1, liquid wax and C 16 ~C 18 Under the liquid phase reaction condition of long-chain olefin molar ratio of 8:1, continuous alkylation reaction was carried out, and the reaction results of the regenerated catalysts under different char regeneration conditions are listed in Table 8. In addition, the linearity of long-chain alkylbenzenes of each regenerated catalyst was comparable to that of the fresh catalyst.

[0117] Table 8 Investigation results of alkylation catalyst coke regeneration conditions and regeneration performance

[0118]

[0119] Comparing the data in Table 8 with the fresh catalyst reaction results under the corresponding alkylation conditions in Table 7 (the fresh catalyst olefin conversion rate is 99.55%, the long-chain alkylbenzene selectivity is 98.69%, and the activity stability time is 2650h), it can be seen that the olefin conversion rate of the regenerated catalyst obtained after the coking deactivated catalyst is regenerated by burning under the conditions in Table 8 is slightly lower than that of the fresh catalyst, while the long-chain alkylbenzene selectivity and activity stability time of the regenerated catalyst are slightly better than those of the fresh catalyst. The reason may be that after the alkylation reaction and the burning regeneration process, the surface acidity of the alkylation molecular sieve catalyst changes, which improves the reaction selectivity and reduces the catalyst coking deactivation rate. It can be seen that the alkylation molecular sieve catalyst has good coking regeneration performance.

[0120] Example 12: Hydrotreating of alkylation products

[0121] Using a method similar to that of Example 4, 4.0 g of the 20-40 mesh CAT-2 molecular sieve catalyst prepared in Example 2 was used to 10 ~C 13 Long chain olefins and C 10 ~C 13 The mixed raw material of liquid wax is input into the reactor, wherein the molar ratio of liquid wax to long-chain olefin is 9:1, and the molar ratio of benzene to long-chain olefin is 20:1. At a temperature of 250°C, a pressure of 4.0 MPa, and a mass space velocity of 1.0 h -1 Under the liquid phase reaction conditions, the alkylation reaction was continued, and the effluent from the reactor was collected as the hydrogenation refining raw material 1. The raw material 1 was separated by vacuum distillation to obtain C 10 ~C 13The long-chain alkylbenzene fraction was used as the hydrofining raw material 2. The bromine index of raw material 1 and raw material 2 was measured to be 313.22 mgBr / 100g and 206.51 mgBr / 100g respectively. The two raw materials were used for hydrofining reaction to examine the effect of hydrofining on removing olefin impurities (mainly phenyl olefin impurities).

[0122] Use fixed bed hydrogenation reaction device to carry out hydrofining reaction, reactor is internal diameter 10mm, external diameter 14mm, long 100cm stainless steel pipe, hydrogen and hydrogenation raw material are input from reactor upper end, and reactor effluent flows out from lower end.Pd / Al prepared by embodiment 3 of 3.0g O Catalyst is loaded in reactor constant temperature zone, and reactor upper and lower ends are filled with inert quartz sand.At first carry out the catalyst reduction operation of catalyst preparation process, and be full of reactor by the hydrogen of input, then input hydrogen, alkylation reactor effluent or the long-chain alkyl benzene fraction that its distillation separation obtains, carry out hydrofining reaction, collect hydrogenated product, calculate olefin hydrogenation conversion by hydrogenation raw material and product bromine index determination value, two kinds of raw material hydrofining reaction olefin conversion experimental results of different conditions are listed in table 9.

[0123] Table 9 Olefin hydrogenation conversion rate under different hydrorefining conditions

[0124]

[0125]

[0126] From the data in Table 9, it is known that compared with hydrogenation feedstock 2, feedstock 1 has a higher olefin hydrogenation conversion rate in a lower temperature range of 120°C to 200°C, and olefin impurities are completely hydrogenated and saturated, or the olefin hydrogenation conversion rate reaches 100%. As the hydrogenation temperature increases from 260°C to 300°C, the olefin hydrogenation conversion rate of feedstock 2 gradually increases from 96.34% to 99.85%. The reason why olefin impurities in feedstock 1 are more easily hydrogenated and saturated may be that the hydrogenation feedstock contains more benzene and long-chain alkane liquid wax, which increases the solubility of hydrogen, reduces viscosity, and improves the macroscopic reaction rate of hydrogenation. Although the hydrogenation of long-chain alkylbenzene fraction (feedstock 2) requires a higher hydrogenation reaction temperature, due to the small processing capacity of the long-chain alkylbenzene fraction, the required hydrogenation reactor volume is small, the catalyst loading amount is small, and the hydrogenation operation cost is low. Therefore, it is a more reasonable choice to first separate the effluent from the alkylation reactor by distillation to separate benzene, long-chain alkane liquid wax, etc., to obtain a long-chain alkylbenzene fraction, and then carry out hydrogenation to remove olefin impurities.

[0127] At a temperature of 260°C, a pressure of 1.0 MPa, and a mass space velocity of 0.3 h -1 , hydrogenation reaction conditions of hydrogen to oil volume ratio of 3000, the raw material 2 was subjected to hydrogenation refining to remove olefin impurities to obtain the corresponding hydrogenated refined C10 ~C 13 Long-chain alkylbenzene products. According to the National Standard of the People's Republic of China GBT 5177-2008 "Industrial Straight-chain Alkylbenzene", the hydrogenation refining C 10 ~C 13 Long-chain alkylbenzene products, and C 10 ~C 13 Bromine index and refractive index n of long chain alkylbenzenes D 20 , mass fraction of sulfonable substances, and the measurement results are listed in Table 10.

[0128] Table 10 Properties and composition of linear alkylbenzenes produced by hydrorefining and industrial hydrofluoric acid catalysis

[0129] Properties and composition Hydrofining of long chain alkylbenzenes Industrial HF long chain alkylbenzene Bromine index, mgBr / 100g 7.56 14.65 <![CDATA[Refractive index n D 20 > 1.4826 1.4825 Mass fraction of sulfonate, % 97.58 97.56

[0130] As can be seen from Table 10, the bromine index of the long-chain alkylbenzene synthesized by the microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyzed by hydrorefining is greatly reduced to below 10.0 mgBr / 100g, that is, the effect of hydrogenation to remove olefin impurities is significant, and its refractive index and mass fraction of sulfonated substances are equivalent to those of the long-chain alkylbenzene synthesized by the industrial hydrofluoric acid method. This shows that the stability and subsequent processing performance of the long-chain alkylbenzene synthesized by the molecular sieve catalyzed by hydrorefining are better than those of the long-chain alkylbenzene synthesized by the industrial hydrofluoric acid method.

[0131] The above experimental results show that the method for synthesizing long-chain alkyl aromatics using a microporous / mesoporous composite SAPO-5 molecular sieve catalyst of the present invention has high catalyst activity, good activity stability, high selectivity, good product quality, an environmentally friendly process method, and good application prospects.

Claims

1. Application of a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst in the synthesis of long-chain alkyl aromatics; The microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst is prepared as follows: According to the molar ratio of Al2O3:P2O5:SiO2:H2O = 1.0:0.5~1.5:0.2~1.5:40~60, the aluminum source, phosphorus source and deionized water are stirred and mixed for 0.5~5h, and then the silicon source is added while stirring, and the stirring is mixed for 0.5~5h, and then the template R1 is added dropwise while stirring until the pH of the mixed system is 5.5~6.5, and the stirring is continued for 0.5~5h, and then the mixture is stirred according to the molar ratio of Al2O3:template R2=1 .0:0.02-0.10 molar ratio, add template R2 while stirring, continue stirring for 0.5-5h, then place at 150-200℃ for crystallization for 8-72h, filter, wash with water, dry, then heat from 5-40℃ to 500-600℃ at a heating rate of 0.5-10℃ / min, and calcine at a constant temperature for 1-8h, and obtain microporous / mesoporous composite SAPO-5 molecular sieve after crushing, and obtain a molded catalyst after extrusion molding; in, The aluminum source is aluminum oxide monohydrate; The phosphorus source is phosphoric acid; The silicon source is tetraethyl orthosilicate; The template agent R1 is one of tri-n-propylamine, triethylamine, triethanolamine, and diethanolamine, or a mixture of two or more in any proportion; The template R2 is one of cetyltrimethylammonium chloride and cetyltrimethylammonium bromide or a mixture of the two in any proportion.

2. The use according to claim 1, characterized in that In the preparation method of microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst, the extrusion molding operation method is: According to the mass ratio of microporous / mesoporous composite SAPO-5 molecular sieve to alumina monohydrate of 0.1 to 1.8:1, and the ratio of sesbania powder to the total mass of molecular sieve and alumina monohydrate of 0.02 to 0.08:1, the molecular sieve, alumina monohydrate and sesbania powder are mixed for 5 to 30 minutes to obtain a solid mixture, 0.2 to 1.0 times the mass of deionized water is added to the solid mixture, and the mixture is stirred for 5 to 30 minutes; and a dilute nitric acid aqueous solution with a mass fraction of 5 to 10% is added dropwise while stirring, and the dilute nitric acid is The amount of aqueous solution added is sufficient to ensure that the mixture can be kneaded into a mud ball and extruded into strips; the strips are allowed to stand at 5-40°C for 4-24 hours and dried at 90-120°C for 5-24 hours; then the temperature is raised from 5-40°C to 500-600°C at a heating rate of 0.5-10°C / min, and the strips are calcined at a constant temperature for 1-10 hours to obtain a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst with a mass fraction of 10-70% of the microporous / mesoporous composite SAPO-5 molecular sieve, and the remainder is Al2O3.

3. The use according to claim 1, characterized in that The application method is: First, the raw aromatics are fed into the fixed bed alkylation reactor to fill the reactor; then the raw aromatics and raw C6~C 24 The mixture of long-chain olefins and additives is fed into a fixed bed reactor and contacts with a microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst at a temperature of 100-300°C, a pressure of 0.2-10.0 MPa, and a total mass space velocity of 0.1-20.0 h -1 , the ratio of the amount of aromatic hydrocarbon to the long-chain olefin substance is 2 to 50:1, and the ratio of the amount of the additive to the long-chain olefin substance is 0 to 20:1, and the alkylation reaction of aromatic hydrocarbon and long-chain olefin is carried out under liquid phase reaction conditions to generate a product long-chain alkyl aromatic hydrocarbon; Using a portion of the effluent from the alkylation reactor as a circulating fluid to be circulated to the reactor, and another portion as an effluent fluid to be separated into excess feedstock and product by a distillation separation system, wherein the circulation ratio of the circulating fluid to the effluent fluid volume flow rate is 0 to 80; After the catalyst is deactivated, it is burned and regenerated for recycling; In the above method, The aromatic hydrocarbon is one or a mixture of any proportion of benzene, toluene, ethylbenzene, xylene, methylethylbenzene, propylbenzene, and diethylbenzene; The additive is a long-chain alkyl aromatic solvent or a long-chain alkane solvent; the long-chain alkyl aromatic solvent is selected from C6~C 24 One or a mixture of any proportion of long-chain alkyl benzene, toluene, ethylbenzene, xylene, methylethylbenzene, propylbenzene, diethylbenzene; the long-chain alkane solvent is selected from C6 to C 24 One or a mixture of two or more long-chain alkanes in any proportion.

4. The use according to claim 3, characterized in that After the microporous / mesoporous composite SAPO-5 molecular sieve solid acid catalyst is loaded into the reactor, it is first heated at a temperature of 50-500°C, a pressure of 0.1-5.0 MPa, and a nitrogen flow rate to catalyst mass ratio of 0.01-0.1 m 3 / (h﹒g) for 0.5 to 24h nitrogen purge pretreatment.

5. The use according to claim 3, characterized in that The alkylation reaction conditions are: temperature 150-280°C, pressure 0.5-8.0 MPa, total mass space velocity of feed 0.2-5.0 h -1 , the ratio of the amount of aromatic hydrocarbons to long-chain olefins is 5 to 30:1, the ratio of the amount of additives to long-chain olefins is 1 to 10:1, and the circulation ratio of the circulating fluid of the alkylation reactor to the volume flow rate of the effluent fluid to the distillation separation system is 1 to 50.

6. The use according to claim 3, characterized in that The method of regenerating the catalyst by burning after deactivation is: After the alkylation reaction feed is stopped, nitrogen is first introduced into the reactor, and the ratio of nitrogen flow rate to catalyst mass is 0.01-0.5m 3 / (h﹒g), nitrogen purge for 1 to 24 hours to complete the nitrogen purge operation; then, input air, the ratio of air flow to catalyst mass is 0.05 to 0.25m 3 / (h﹒g), with a heating rate of 0.2~5.0℃ / min, the air char regeneration is raised from the initial temperature of 100~400℃ to the end temperature of 450~650℃, and the final temperature is constant for 1.0~24.0h; finally, nitrogen is input, and the ratio of nitrogen flow rate to catalyst mass is 0.01~0.5m 3 / (h﹒g), reduce the reactor catalyst bed temperature from the final charring temperature to the alkylation reaction temperature, and continue nitrogen purging for 1 to 24 hours to complete the catalyst charring regeneration operation.

7. The use according to claim 3, characterized in that The alkylation reaction unit consists of a plurality of reactors operated in parallel or in series, each reactor is loaded with the same or different alkylation catalysts; and the reaction operating conditions of each reactor are the same or different.

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