WO2021258952A1

WO2021258952A1 - Hydrocracking isomerization catalyst, preparation method therefor and use thereof

Info

Publication number: WO2021258952A1
Application number: PCT/CN2021/095464
Authority: WO
Inventors: 李伟; 刘思阳; 关庆鑫
Original assignee: 南开大学
Priority date: 2020-06-23
Filing date: 2021-05-24
Publication date: 2021-12-30
Also published as: CN111701623A; CN111701623B

Abstract

The present invention relates to an alumina-coated molecular sieve composite carrier, a hydrocracking isomerization catalyst, a preparation method therefor and the use thereof. Firstly, a molecular sieve is subjected to a pore-enlarging treatment with an amino acid; then the molecular sieve is sulfonated; the sulfonated molecular sieve is then added into an alcohol-water solution containing cetyltrimethylammonium bromide; then an aluminum source and urea are added; and crystallization, washing, drying and roasting are then performed to obtain the composite carrier. The composite carrier has abundant pore channels and a large number of acidic sites, such that the hydroisomerization performance is high. The catalyst uses Pt, Pd, Ni and Co as primary active metals, and Na, K, Be, Mg, Ca, Sr, Cr, Mn, Fe, Cu and Zn as auxiliary metals, wherein the auxiliary metal can not only improve the dispersity of the active metal, but can also selectively cover and inhibit the acidic sites of the molecular sieve, and play a key role in the hydrogenation activity. The catalyst has a better activity in the preparation of a biofuel from a long-chain alkane by means of hydroisomerization.

Description

Hydrocracking isomerization catalyst and preparation method and application thereof

Technical field

The invention belongs to the technical field of catalysis, and particularly relates to a hydrocracking isomerization catalyst and a preparation method and application thereof.

Background technique

In recent decades, the concentration of pollutants in the atmosphere has increased considerably, especially greenhouse gases that cause climate change. Carbon dioxide emissions mainly come from power generation and transportation. In the next three decades, the carbon dioxide emissions caused by transportation will increase from 16% to 79%. In recent years, the international air traffic volume in the transportation sector has doubled, while road traffic has increased by 50%. Aviation kerosene and diesel fuel are the main fuels needed for the growth of the transportation sector. Therefore, the development of efficient, sustainable and renewable aviation fuel technology is particularly important. Bio-aviation fuel is recognized by the International Air Transport Association as the most promising strategy for reducing carbon dioxide emissions in the aviation industry.

Fossil aviation fuel is composed of approximately 20% paraffin wax, 40% isoparaffin wax, 20% naphthenic and 20% aromatic hydrocarbons. The composition of bio-jet fuel is similar to that of fossil jet fuel. It is a mixture of mainly C9-C16. It is composed of hydrocarbons, and bio-jet fuel does not contain sulfur and has a low content of aromatic compounds. Therefore, the combustion of bio-jet fuel releases fewer particles than the combustion of fossil jet fuel. However, the lack of aromatic compounds can cause the wear of certain types of engines, and they can cause the engine's O-rings and seals to expand. Therefore, a 50% volume mixture of bio-jet fuel and fossil fuel is used as the standard. However, aromatic compounds can be added to bio-jet fuel, in which case it is technically feasible to use 100% bio-jet fuel in aircraft engines.

CN108144638A discloses a catalyst for the preparation of aviation kerosene from microalgae biodiesel. The catalyst uses mesoporous Y molecular sieve as a carrier and metal Ni as a supported metal. The reaction time is 8 hours, the H ₂ pressure is 3 MPa, and the reaction temperature is At 400°C, microalgae biodiesel can be converted into high-quality aviation kerosene on a fixed bed reactor. CN106540743A discloses a catalyst for the preparation of bio-aviation fuel from Jatropha oleifera oil and a preparation method thereof. The catalyst used is NiMo/Al-MCM-41, which reacts at a reaction temperature of 330-370°C, and the obtained product is cooled, The bio-aviation fuel is obtained by removing the water, and the appearance is a clear and transparent liquid. In the catalyst activity evaluation experiment, the conversion rate of the jatropha oil hydrodeoxygenation cracking isomerization was 100%, and the aviation fuel yield was 21.5%-73.9%. CN110257098A discloses a method for preparing bio-aviation fuel and biodiesel by thermally chemical conversion of bio-oils and reducing reaction activation energy. The bio-oils are prepared through the processes of catalytic cracking, aromatization, hydrogenation and distillation to obtain carbon chain lengths of C8-C15 Components of bio-aviation fuel and biodiesel with a carbon chain length of C16-C24 components; the catalyst used in the catalytic cracking process is tin oxide or iron oxide, and the mass consumption of the cracking catalyst is 1%-15% of the bio-oil. The catalytic cracking temperature is less than 410°C. IH Choi et al. reported a catalyst with metal Pd as the active component and Beta as the carrier, using waste catering as a raw material. After the hydrogenation reaction, the raw material conversion rate was as high as 100%, and the aviation kerosene selectivity in the product reached 69.3 %. This catalyst is also suitable for the catalytic cracking of soybean oil, and can obtain a raw material conversion rate of 60.77% under the condition of 300°C, and the selectivity of aviation kerosene can reach 30.1%. Cen Ke, a court judge of Zhejiang University, used NiMo loaded on HY molecular sieve to convert soybean oil into aviation fuel to produce high-quality jet fuel with high alkanes and low aromatics. Under 4MPa hydrogen pressure, the reaction temperature was increased from 390°C to 410°C, and the yield of jet fuel on NiMo/HY catalyst was increased from 0% to 49.1%. Under the condition of 1MPa low hydrogen pressure, the yield was 48.2%. Of jet fuel. Professor Fang Yunming of Beijing University of Chemical Technology first used Pt/USY, Pt/ZSM-12, and Pt/ZSM-22 catalysts for the hydroisomerization of n-pentadecane. After evaluation and comparison, it was found that Pt/ZSM-12 catalysts can The n-pentadecane is converted into multi-branched isomers and single-branched isomers. After that, the catalyst is used for the hydrogenation of algae lipids. The product can obtain aviation kerosene with a yield of up to 60%. The fuel meets the specifications of the ASTM 7566 standard.

In view of the fact that most of the existing hydrogenation catalysts use precious metals, and the catalysts have high reaction temperature, low aviation fuel component selectivity, poor catalyst stability and other shortcomings, the present invention provides a highly active hydrocracking Isomerization catalyst and preparation method, and its application in the hydrocracking and isomerization of long-chain alkanes. By adjusting the process parameters, high-selectivity gasoline, kerosene or diesel can be produced as required, and the raw material yield is as high as 90%, and the reaction is mild, there is no flying temperature, and the catalyst has good stability.

Summary of the invention

In order to solve the above technical problems, the present invention provides a composite carrier of alumina-coated molecular sieve, a hydrocracking isomerization catalyst, and a preparation method and application thereof.

The technical scheme adopted by the present invention is: a composite carrier of alumina-coated molecular sieve, which has a core-shell structure, the inner core is a molecular sieve, the outer shell is alumina, and the inner molecular sieve and the outer shell alumina are connected by p-toluenesulfonic acid groups.

Preferably, the molecular sieve has been treated with amino acids in advance;

Preferably, the amino acid is one or more of aspartic acid, glutamic acid, lysine, arginine and histidine;

Preferably, the amino acid is glutamic acid, and the mass fraction is 1-5%.

Preferably, the molecular sieve is one or more of ZSM-5, Beta, USY, HY, mesoporous Y, rare earth Y, mordenite, SAPO-5, SAPO-11 and SAPO-34;

Preferably, the molecular sieve is USY.

The method for preparing a composite carrier of alumina-coated molecular sieve includes the following steps:

Molecular sieve pretreatment: The molecular sieve is first treated with amino acids, and then the p-toluenesulfonic acid group is grafted onto the molecular sieve to obtain a modified sulfonated molecular sieve;

Preparation of composite carrier: mix the modified sulfonated molecular sieve, aluminum source and urea, and obtain a composite carrier of alumina-coated molecular sieve after crystallization;

Preferably, the aluminum source includes one or more of pseudo-boehmite, aluminum isopropoxide, aluminum acetylacetonate and aluminate coupling agent; preferably aluminum isopropoxide;

Preferably, the molar ratio of urea to aluminum source is 0.02-0.1, and the stirring reflux temperature is 25-80°C;

Preferably, the mass percentage of the sulfonated molecular sieve in the composite carrier is 1-20%; preferably 10%;

Preferably, the modified sulfonated molecular sieve is added to the alcohol aqueous solution containing cetyltrimethylammonium bromide, and then the aluminum source and urea are added;

Preferably, in the alcohol aqueous solution, the mass ratio of cetyltrimethylammonium bromide is 1-5%, and the mass ratio of ethanol to water is 0.5-2.

Preferably, the specific process of molecular sieve pretreatment is: adding molecular sieve to the amino acid solution, stirring and refluxing reaction, putting the obtained amino acid-treated molecular sieve product into p-toluenesulfonic acid solution, stirring and refluxing reaction to obtain modified sulfonated molecular sieve;

Preferably, the mass fraction of the amino acid solution is 1-5%, and the mass fraction of the p-toluenesulfonic acid solution is 1-5%;

Preferably, the reflux temperature for two stirrings is 25-80°C.

A hydrocracking isomerization catalyst containing a composite carrier containing alumina-coated molecular sieve.

In the method for preparing the hydrocracking isomerization catalyst, the active components are loaded on the composite carrier of the alumina coated molecular sieve by an equal volume impregnation method, and the hydrocracking isomerization catalyst is obtained by drying and roasting.

Preferably, the active component includes the main active metal component and the auxiliary metal component;

Preferably, the main active metal component is Pt, Pd or Ni, Co, accounting for 0.5-1% or 5-20% of the catalyst;

Preferably, the promoter metal component is Na, K, Be, Mg, Ca, Sr, Cr, Mn, Fe, Cu, Zn, which accounts for 0.5-10% of the catalyst.

The application of the hydrocracking isomerization catalyst in the hydrocracking isomerization is specifically used for the hydrogenation of the hydrodeoxygenation products of animal and vegetable fats and oils to prepare biological aviation kerosene.

The advantages and positive effects of the present invention are:

(1) The molecular sieve treated with amino acid increases its specific surface area, improves the reaction rate and catalytic activity, and the aluminum oxide is wrapped on the outer surface of the molecular sieve, which not only improves the combination efficiency of the two, but also improves the mechanical strength of the carrier , Can also give full play to the catalysis of the lewis acid of alumina, and the carrier has a rich pore structure, mesoporous and macroporous alumina, and mesoporous and microporous molecular sieves, which can not only improve the mass transfer of the catalyst The speed can also enable the reaction products to pass through the pores in time, thereby avoiding secondary cracking and improving the selectivity of jet fuel components;

(2) The auxiliary metal not only improves the dispersion of the main active metal, but also covers and inhibits some strong acid sites, which can make the reaction proceed more moderately without flying temperature, and it also affects the components of jet fuel. The increase in selectivity played a key role;

(3) Due to the high activity of the catalyst and mild reaction, the raw material utilization rate is high, there are few gaseous alkanes, and the reaction temperature can be adjusted according to needs, and different fuel components can be obtained, including gasoline, kerosene and diesel. Different fuels, and high product isomer ratio, the distilled fuel is in full compliance with national standards.

Description of the drawings

Figure 1 SEM image of alumina-coated USY composite carrier in cat1;

Figure 2 XRD patterns of cat6, cat7, cat8, cat9, cat10, and cat11 after reduction;

_{Figure 3 H 2} -TPR patterns of cat6, cat7, cat8, cat9, cat10, and cat11;

_{Figure 4 NH 3} -TPD diagrams of cat6, cat7, cat8, cat9, cat10, and cat11 after reduction.

detailed description

The invention relates to a preparation method of a hydrocracking isomerization catalyst and its application in the hydrogenation of long-chain alkanes to prepare biofuels. The present invention firstly expands the molecular sieve with amino acids, then sulfonates the molecular sieve, then adds the sulfonated molecular sieve to the alcohol aqueous solution containing cetyltrimethylammonium bromide, and then adds the aluminum source and urea The composite carrier is obtained through crystallization, washing, drying, and roasting. This composite carrier has abundant pores and a large number of acidic sites, which makes the hydroisomerization performance high. It is used to prepare aviation kerosene by the hydroisomerization of long-chain alkanes. It has high activity. Then impregnate the loaded metal, after roasting, a highly active and highly selective catalyst can be obtained, using Pt, Pd, Ni, Co as the main active metals, Na, K, Be, Mg, Ca, Sr, Cr, Mn , Fe, Cu, Zn are used as auxiliary metals. The auxiliary metals can not only improve the dispersion of active metals, but also selectively cover and inhibit the acidic sites of molecular sieves, which play a key role in hydrogenation activity. The prepared hydroisomerization catalyst can be applied to the hydrocracking and isomerization of long-chain alkanes to prepare biological aviation kerosene, and can meet the requirements of various processes.

In the present invention, the molecular sieve is first treated with amino acids. During the treatment, the ionization of amino acids is accelerated by heating and refluxing, so that the ionized H ⁺ ions or NH ₄ ⁺ make the environment acidic or alkaline, and the amino acids will be etched away Part of the framework silicon and framework aluminum, thereby introducing more mesoporous structure, which will increase the mass transfer rate of the reaction, make the reaction raw materials and the catalyst contact more fully, thereby improving the reaction activity.

In order to make the combination of the aluminum source more uniform, in the solution of the present invention, a certain proportion of cetyltrimethylammonium bromide is added to promote the aluminum source to generate a mesoporous-macroporous structure. Among them, the alumina molecular sieve itself has a rich mesoporous structure, and the macropores in it come from the formation of micelles in cetyltrimethylammonium bromide. The micelles can block the accumulation of aluminum sources and expand the aluminum source. Dispersion, after the micelles are calcined, a large number of macroporous structures are exposed and the porosity of the carrier is improved. In addition, urea is added to the sol. Part of the ammonium ion can be released through the partial hydrolysis of urea in hot water to increase the alkalinity of the entire system. However, in the alkaline system, cetyltrimethylammonium bromide is The solubility will increase, thereby improving the overall order of cetyltrimethylammonium bromide in the system, and the particle size of the micelles formed during the crystallization process will be more uniform, making the pores after the final calcination more uniform .

The sulfonation treatment of the molecular sieve after amino acid treatment can make the surface of the molecular sieve graft a layer of toluenesulfonic acid groups. These groups will strengthen the affinity of the molecular sieve and cetyltrimethylammonium bromide. The methyl ammonium bromide micelles will be adsorbed on the outside of the molecular sieve by the sulfonic acid group, and the sulfonated molecular sieve will be coated in it. During the calcination process, the cetyl trimethyl bromide inside the large pores of the alumina The ammonium micelles will be removed, leaving the molecular sieves inside the micelles, which remain in the pores of the alumina molecular sieve.

In some embodiments of the present invention, the alumina-coated molecular sieve composite carrier has a core-shell structure, the inner core is a molecular sieve, and the outer shell is alumina, and the inner molecular sieve and the outer shell alumina are connected by p-toluenesulfonic acid groups. The preparation method is as follows:

(1) First, add molecular sieve to the amino acid solution with a mass fraction of 1-5%, and the molecular sieve with a mass fraction of 5-20%, then stir and reflux at 25-80℃ for 2-8h, then filter, wash and dry , Then add the dried sample to the dilute solution of p-toluenesulfonic acid with a mass fraction of 1-5%, sonicate for 2h to form a suspension, then stir and reflux at 25-80℃ for 2-8h, then wash and dry , To obtain modified sulfonated molecular sieve.

(2) Add the sulfonated molecular sieve to the alcohol aqueous solution of cetyltrimethylammonium bromide with a mass percentage of 1-5% (the alcohol-water mass ratio is 1:4) at 25-80°C, sulfonate The mass percentage of the molecular sieve in the composite carrier is 1-20%, preferably 10%; after stirring for 2 hours, add aluminum source and urea (the molar ratio of urea to aluminum source is 0.02-0.1), reflux treatment for 2-8 hours, and then Crystallize at 50-100°C for 12-24 hours, centrifuge, wash, and dry the sample after crystallization, and calcinate in a muffle furnace at 600°C for 2 hours to obtain a composite carrier of alumina-coated molecular sieve.

Among them, the molecular sieve is a mixture of one or more of ZSM-5, Beta, USY, HY, mesoporous Y, rare earth Y, mordenite, SAPO-5, SAPO-11 and SAPO-34, preferably USY; A mixture of one or more of aspartic acid, glutamic acid, lysine, arginine and histidine can be used, preferably glutamic acid; the aluminum source can be pseudo-boehmite, isopropyl One or more of aluminum alkoxide, aluminum acetylacetonate and aluminate coupling agent, preferably aluminum isopropoxide;

In certain embodiments of the present invention, it also relates to a hydrocracking isomerization catalyst comprising a composite carrier coated with alumina-coated molecular sieve. For chemical catalyst, the following steps can be specifically adopted:

The metal loading adopts an equal volume impregnation method. The active component includes the main active metal component and the auxiliary metal component. First, the two metal salts are added to the water with the same volume of water absorption of the carrier. After stirring for 2 hours, a clear solution is formed. Then add dropwise to the carrier, mix and stir uniformly, let stand at room temperature for 24h, then put it in an oven at 120°C for 2h, calcined in a muffle furnace at 500°C for 2h to obtain the hydrocracking isomerization catalyst .

Among them, the main active metal components are Pt, Pd or Ni, Co, accounting for 0.5-1% or 5-20% of the catalyst; the promoter metal components are Na, K, Be, Mg, Ca, Sr, Cr, Mn, Fe, Cu, Zn account for 0.5-10% of the catalyst.

In some embodiments of the present invention, the hydrocracking isomerization catalyst can be used in hydrocracking and isomerization, specifically, it can be used in various types of alkane cracking and isomerization reactions. In practical applications, it can also be used in plants and animals. Hydrogenation of oil and fat hydrodeoxygenation products to produce biological aviation kerosene.

The following further illustrates this solution through specific embodiments.

Example 1: Hydrocracking and isomerization catalyst used in the hydrocracking and isomerization of palm oil hydrodeoxygenation products

The reaction raw material is palm oil hydrodeoxygenation product, that is, palm oil is hydrodeoxygenated with hydrodeoxygenation catalyst, space velocity is 1h, reaction temperature is 350℃, hydrogen-oil ratio is 1333, reaction pressure is 5MPa, and hydrogenation is obtained. The deoxygenation products are C5-C14, C15-C18, water, and gas phase products (CO, CH ₄ , C ₂ H ₅ , C ₃ H ₆ ); the C15-C18 product is separated and used as the raw material for the hydrocracking isomerization reaction The reaction is carried out, wherein the mass ratios of the raw alkane mixtures C15, C16, C17, and C18 are 20%, 11%, 47%, and 22% in sequence.

Among them, the hydrodeoxygenation catalyst can be an existing hydrodeoxygenation catalyst, such as the hydrodeoxygenation catalyst involved in patent number CN 104525247 B. Then use the hydrocracking isomerization catalyst prepared above, adjust the reaction temperature to the required temperature, and increase the hydrogen pressure in the reaction tube to 3MPa, the liquid hourly space velocity of the alkane is 1h ^-1 , and the volume ratio of the hydrogen to the alkane It is 800, so as to proceed the hydroisomerization cracking reaction.

Example 2: Hydrocracking and isomerization catalyst used in the hydrocracking and isomerization of castor oil hydrodeoxygenation products

The reaction raw material is castor oil hydrodeoxygenation product, that is, palm oil is hydrodeoxygenated with hydrodeoxygenation catalyst, space velocity is 1h, reaction temperature is 350℃, hydrogen-oil ratio is 1333, reaction pressure is 5MPa, and hydrogenation is obtained. The deoxygenation products are C5-C14, C15-C18, water, and gas phase products (CO, CH ₄ , C ₂ H ₅ , C ₃ H ₆ ); the C15-C18 product is separated and used as the raw material for the hydrocracking isomerization reaction The reaction is carried out, wherein the mass ratios of the raw alkane mixtures C15, C16, C17, and C18 are 7%, 6%, 47%, and 40% in sequence.

The hydrodeoxygenation catalyst can use the same catalyst as in Example 1, and then apply the hydrocracking isomerization catalyst prepared above to adjust the reaction temperature to the desired temperature, and increase the hydrogen pressure in the reaction tube to 3MPa, The liquid hourly space velocity is 1h ^-1 , and the volume ratio of hydrogen to alkanes is 800, so that the hydroisomerization cracking reaction is carried out.

Example 3: Hydrocracking and isomerization catalyst used for hydrocracking and isomerization of palmitoleate methyl ester hydrodeoxygenation products

The reaction raw material is the product of methyl palmitoleate hydrodeoxygenation. The reaction system is the same as in Example 1 or Example 2. The mass ratios of the raw material alkane mixtures C15, C16, C17, and C18 are 15%, 18%, 45%, respectively. twenty two%.

Example 4: Hydrocracking and isomerization catalyst used for hydrocracking and isomerization of waste oil hydrodeoxygenation products

The reaction raw material is the waste oil hydrodeoxygenation product, and the reaction system is the same as that of Example 1 or Example 2, wherein the mass ratios of the raw alkane mixtures C15, C16, C17, and C18 are 22%, 20%, 30%, 28%, respectively.

Example 5: Preparation of Alumina Coated 10% USY Molecular Sieve Composite Carrier

(1) Preparation of composite carrier:

①First prepare the aspartic acid solution with a mass fraction of 5%, the mass of water is 237.5g, the mass of aspartic acid is 12.5g, stir for 1h at room temperature until all is dissolved, then add 10g USY molecular sieve, stir and reflux at 80℃ for 8h , And then filter the treated molecular sieve, wash the solid filtrate with deionized water to neutrality, and dry at 120°C to obtain aspartic acid-modified USY molecular sieve.

②Add 5g of p-toluenesulfonic acid in a container with 250g of water and stir well. Weigh 10g of aspartic acid-modified USY molecular sieve and pour into the above solution, stir and mix well and sonicate for 2h to obtain a suspension. Stir and reflux in a water bath at 80°C for 8 hours, filter the treated molecular sieve, and put the solid filtrate into an oven at 120°C for 2 hours to dry to obtain a sulfonated USY molecular sieve.

③Weigh 49g ethanol and 196g deionized water, reflux at 80℃ and stir evenly, add 5g cetyltrimethylammonium bromide, stir well, add 1g sulfonated USY molecular sieve, stir for 2h, add 36g isopropanol Stir the aluminum for 2 hours, then add 1.1 g of urea, and continue to reflux for 8 hours. After the reflux, put the obtained sol into a polytetrafluoroethylene lining, put it into a hydrothermal reactor, and crystallize in a constant temperature oven at 80°C for 24 hours. After crystallization, cool to room temperature, take out the crystallization product and filter, wash the solid filter with deionized water to neutral, put it in a 120℃ oven for 2h, put it in a muffle furnace with 600℃ air It is calcined in an atmosphere for 2 hours to obtain a composite carrier with 10% USY molecular sieve coated with alumina.

Example 6: Preparation of Alumina Coated USY Molecular Sieve Composite Carrier

The specific preparation steps are the same as in Example 5. Take 0.5 g of the sulfonated USY molecular sieve and add it to the alcohol aqueous solution of cetyltrimethylammonium bromide, and the final product is a composite carrier of alumina coated 5% USY molecular sieve.

Correspondingly, 1.5g of sulfonated USY molecular sieve was added to the alcohol aqueous solution of cetyltrimethylammonium bromide, and the final product was a composite carrier of 15% USY molecular sieve coated with alumina; 2.0g of sulfonated USY The molecular sieve is added to the alcohol aqueous solution of cetyltrimethylammonium bromide, and the final product is a composite carrier of alumina coated 20% USY molecular sieve;

Example 7: Preparation of composite carrier with 10% mesoporous Y molecular sieve coated with alumina

Preparation of composite carrier:

①First prepare the aspartic acid solution with a mass fraction of 5%, the mass of water is 237.5g, the mass of aspartic acid is 12.5g, stir for 1h at room temperature until all is dissolved, then add 10g of mesoporous Y molecular sieve and stir at 80℃ Reflux for 8 hours, then filter the treated molecular sieve, wash the solid filtrate with deionized water to neutrality, and dry at 120°C to obtain an aspartic acid-modified mesoporous Y molecular sieve.

②Add 5g of p-toluenesulfonic acid into a container with 250g of water, stir well, weigh 10g of aspartic acid-modified mesoporous Y molecular sieves, pour into the above solution, stir and mix well and sonicate for 2h to obtain a suspension. Then, it was stirred and refluxed in a water bath at 80°C for 8 hours, the treated molecular sieve was filtered, and the solid filtrate was placed in an oven at 120°C to dry for 2 hours to obtain a sulfonated mesoporous Y molecular sieve.

③Weigh 49g of ethanol and 196g of deionized water, reflux and stir evenly at 80℃, add 5g of cetyltrimethylammonium bromide, stir evenly, add 1g of sulfonated mesoporous Y molecular sieve, stir for 2h, add 36g of iso Stir the aluminum propoxide for 2 hours, then add 1.1 g of urea, and continue to reflux for 8 hours. After the reflux is completed, put the obtained sol into a polytetrafluoroethylene lining, put it into a hydrothermal reactor, and crystallize in a constant temperature oven at 80°C. After crystallization for 24h, cool to room temperature after crystallization, take out the crystallization product and filter, wash the solid filtrate with deionized water to neutrality, put it in an oven at 120℃ for 2h, put it in a muffle furnace for 600 It is calcined in an air atmosphere at ℃ for 2h to obtain a composite carrier with 10% mesoporous Y molecular sieve coated with alumina.

Example 8: Preparation of composite carriers of different molecular sieves

The preparation steps are the same as in Example 7, using HY molecular sieves, ZSM-5 molecular sieves, SAPO-11 molecular sieves, mordenite molecular sieves and Beta molecular sieves to replace the mesoporous Y molecular sieves to prepare alumina-coated 10% HY molecular sieve composite carrier, alumina A composite carrier coated with 10% ZSM-5 molecular sieve, a composite carrier with 10% SAPO-11 molecular sieve coated with alumina, a composite carrier with 10% mordenite molecular sieve coated with alumina, and a composite carrier with 10% Beta molecular sieve coated with alumina.

In the above Examples 5-8, the aspartic acid solution treatment is taken as an example, and other types of amino acid solutions, such as glutamic acid, lysine, arginine, and histidine solutions, can also be replaced according to requirements. The preparation method is the same as that described above. The embodiments are the same; correspondingly, the aluminum source used in the preparation process can be replaced with pseudo-boehmite, aluminum acetylacetonate or aluminate coupling agent.

Example 9: Preparation of Hydrocracking Isomerization Catalyst

Active component load:

Weigh 10g deionized water in a beaker, weigh 4.52g nickel nitrate heptahydrate and 0.48g magnesium nitrate tetrahydrate into the beaker, stir for 2h at room temperature until completely dissolved; weigh 8g uniformly ground alumina wrapped 10% USY molecular sieve Put the above-mentioned composite carrier into a petri dish, add the above mixed solution dropwise to the composite carrier, stir for 1h to make it evenly mixed, let stand at room temperature for 24h, put it in an oven at 80℃ for 2h, and then put it in an oven at 120℃ for drying Dry for 2 hours, and finally grind the obtained sample evenly, put it in a muffle furnace and roast it in an air atmosphere at 500°C for 2 hours to obtain the hydrocracking catalyst. After that, grind the roasted catalyst evenly and press it through a mold to crush it. And sieving out the particles of 20-40 mesh, denoted as cat 1.

Among them, the mass fractions of the active metal component and the auxiliary metal component of the cat 1 active component are 10% Ni+0.5% Mg respectively. In addition, according to the above steps, load the active components of different proportions and components on different types of composite carriers in sequence. Correspondence of carrier type, load capacity and sample serial number are shown in Table 1.

Table 1

cat 1-20 hydrocracking isomerization catalysts can be used in the reaction system of Examples 1-4, and can be used in hydrocracking isomerization.

Comparative example 1: Preparation of hydrocracking isomerization catalyst _{with γ-Al 2} O _{3 as carrier}

First weigh 10g deionized water into a beaker, weigh 4.60g nickel nitrate heptahydrate and 1.94g magnesium nitrate tetrahydrate (10%Ni+2%Mg) into the beaker, stir for 2h at room temperature until completely dissolved, then weigh Put 8g of uniformly ground γ-Al ₂ O ₃ into a petri dish, add the above mixture and dissolve dropwise to the γ-Al ₂ O ₃ carrier, stir with a horn spoon for 1 hour to make it evenly mixed, and then stand at room temperature for 24 hours. Dry in an oven at 80℃ for 2h, then put it in an oven at 120℃ for 2h, and finally grind the obtained sample evenly, put it in a crucible, and bake it in a muffle furnace at 500℃ for 2h to obtain hydrogenation. After cracking the catalyst, the calcined catalyst is ground uniformly, and then compressed through a mold, crushed and sieved to obtain particles of 20-40 mesh, which is recorded as cat 21.

Comparative example 2: Preparation of hydrocracking isomerization catalyst with 10% USY directly blended with 90% Al ₂ O _{3 as a carrier}

Preparation of composite carrier: Weigh 1g of USY molecular sieve and 9g of γ-Al ₂ O ₃ in a beaker containing 100ml of deionized water, stir at room temperature for 3 hours, then filter, and finally put it in an oven at 120°C for 2 hours, and then put it in an oven at 120°C for 2 hours. It is fired in a muffle furnace at 600° C. for 2 hours under an air atmosphere to obtain _{a composite carrier of 90% γ-Al 2} O ₃ mixed with 10% USY.

The loading process of the active component is the same as that in Example 9. _{The composite carrier of 90% γ-Al 2} O ₃ blended with 10% USY is used. The mass fraction of the active metal component and the auxiliary metal component in the active component are 10 respectively. %Ni+2%Mg, the prepared catalyst is denoted as cat 22.

Comparative example 3: Preparation of hydrocracking isomerization catalyst using sulfonated USY without amino acid treatment as a carrier

Preparation of composite carrier:

①Put 5g of p-toluenesulfonic acid in a three-necked flask containing 250g of water, stir well, then weigh 10g USY molecular sieve and pour into the above solution, stir and mix well, put it in an ultrasonic cleaner and sonicate for 2h to obtain a suspension, then Stir and reflux in a water bath at 80°C for 8 hours, filter the treated molecular sieve, and then put the filter cake in an oven at 120°C to dry for 2 hours to obtain a sulfonated USY molecular sieve.

②Weigh 49g ethanol and 196g deionized water in a three-necked flask, reflux and stir evenly at 80℃, add 5g cetyltrimethylammonium bromide, stir well, add 1g sulfonated USY molecular sieve and stir for 2h, then add 36g aluminum isopropoxide was stirred for 2h, and then 1.1g urea was added, and reflux was continued for 8h. After the reflux, the obtained sol was put into the polytetrafluoroethylene liner, and put into the hydrothermal reaction kettle, and kept in a constant temperature oven at 80℃. After crystallization for 24h, cool to room temperature after crystallization, take out the crystallization product and filter, wash the filter cake with deionized water to neutrality, and finally put it in an oven at 120℃ to dry for 2h, and then put it in the horse It was calcined in an air furnace at 600°C for 2 hours to obtain a composite carrier with 10% USY molecular sieve coated with non-amino acid treatment alumina.

The loading process of the active component is the same as in Example 9. The composite carrier of 10% USY molecular sieve coated with non-amino acid treatment alumina is used, and the mass fractions of the active metal component and the auxiliary metal component in the active component are 10% Ni+. 2% Mg, the prepared catalyst is denoted as cat 23.

Comparative example 4: Preparation of hydrocracking and isomerization catalyst by using Wujinghua USY as a carrier

Preparation of composite carrier:

①First prepare a 5% mass fraction of aspartic acid solution in a three-necked flask. The mass of water is 237.5g, and the mass of aspartic acid is 12.5g. Stir at room temperature for 1h until all is dissolved, and then add 10g USY molecular sieve. Stir and reflux in a constant temperature water bath at 80°C for 8 hours, then filter the treated molecular sieves, wash the filter cake with deionized water to neutrality, and finally put it into an oven at 120°C to dry to obtain amino acid-modified USY molecular sieves.

②Add 5g of p-toluenesulfonic acid into a three-necked flask containing 250g of water, stir well, then weigh 10g of aspartic acid-modified USY molecular sieves into the above solution, stir and mix well, and put it in an ultrasonic cleaner. 2h to obtain the suspension, then stir and reflux in a water bath at 80°C for 8h, filter the treated molecular sieve, and then put the filter cake in an oven at 120°C to dry for 2h to obtain a sulfonated USY molecular sieve.

③Weigh 49g ethanol and 196g deionized water in a three-necked flask, reflux and stir evenly at 80℃, add 5g cetyltrimethylammonium bromide, stir well, add 1g sulfonated USY molecular sieve and stir for 2h, then add 36g aluminum isopropoxide was stirred for 2h, and then 1.1g urea was added, and reflux was continued for 8h. After the reflux, the obtained sol was put into the polytetrafluoroethylene liner, and put into the hydrothermal reaction kettle, and kept in a constant temperature oven at 80℃. After crystallization for 24h, cool to room temperature after crystallization, take out the crystallization product and filter, wash the filter cake with deionized water to neutrality, and finally put it in an oven at 120℃ to dry for 2h, and then put it in the horse It is calcined in a Furnace at 600°C for 2 hours under an air atmosphere to obtain a composite carrier with 10% USY molecular sieve coated with crystal-free alumina.

The loading process of the active component is the same as in Example 9. The composite carrier of 10% USY molecular sieve is coated with crystal-free alumina. The mass fraction of the active metal component and the auxiliary metal component in the active component are 10% Ni+. 2% Mg, the prepared catalyst is denoted as cat 24.

Comparative Example 5: Preparation of a hydrocracking isomerization catalyst with a composite carrier of 10% USY molecular sieve coated with urea-free alumina

(1) Preparation of composite carrier:

③Weigh 49g ethanol and 196g deionized water in a three-necked flask, reflux and stir evenly at 80℃, add 5g cetyltrimethylammonium bromide, stir well, add 1g sulfonated USY molecular sieve and stir for 2h, then add 36g aluminum isopropoxide was stirred for 2h, and then 1.1g urea was added, and reflux was continued for 8h. After the reflux, the obtained sol was put into the polytetrafluoroethylene liner, and put into the hydrothermal reaction kettle, and kept in a constant temperature oven at 80℃. After crystallization for 24h, cool to room temperature after crystallization, take out the crystallization product and filter, wash the filter cake with deionized water to neutrality, and finally put it in an oven at 120℃ to dry for 2h, and then put it in the horse It is calcined in a furnace at 600°C for 2 hours under an air atmosphere to obtain a composite carrier with 10% USY molecular sieve coated with urea-free alumina.

The loading process of the active component is the same as in Example 9. The composite carrier of 10% USY molecular sieve coated with urea-free alumina is used. The mass fraction of the active metal component and the auxiliary metal component in the active component are 10% Ni+2. %Mg, the prepared catalyst is recorded as cat 25.

Comparative Example 6: Preparation of Hydrocracking Isomerization Catalyst by Single Metal Supported Composite Molecular Sieve

The preparation of the composite carrier was the same as the preparation steps of Example 5, and the composite carrier with 10% USY molecular sieve coated with alumina was prepared.

Active component load:

First, weigh 10g of deionized water into a beaker, weigh 4.49g of nickel nitrate heptahydrate (10% Ni) into the beaker, stir for 2h at room temperature until it is completely dissolved, then weigh 8g of the evenly ground composite carrier into a petri dish , Add the above mixed dissolution dropwise to the composite carrier, stir with a horn spoon for 1 hour to make it evenly mixed, then let it stand at room temperature for 24 hours, put it in an oven at 80°C for 2 hours, and then put it in an oven at 120°C for 2 hours. Finally, grind the obtained sample evenly, put it in a crucible and roast it in a muffle furnace at 500℃ for 2h to obtain a hydrocracking catalyst. After that, grind the roasted catalyst evenly and press it through a mold to crush it. And sieving out the particles of 20-40 mesh, record it as cat 26.

Cat 1-26 catalyst was used in the reaction system of Example 1 to further evaluate the catalytic effect of each catalyst. The catalytic results of each catalyst are shown in the following table.

Table 2 Evaluation results of cat1, cat2, cat3, cat4, cat5

It can be seen from Table 2 that the addition of the promoter metal has a greater impact on the catalytic effect. The catalyst without the promoter metal is too active, and the conversion rate reaches 100% at a low temperature of 250 ℃, but most products They are all C5-C8 components, and the jet fuel component is only 15%. With the increase of additives, it has a significant effect on the improvement of the selectivity of aviation fuel components. The additives metal above 1% has a greater impact on the catalytic effect, and the highest selectivity of aviation fuel components is above 69%. Moreover, the isomer ratio is high, and with the increase of the auxiliary metal content, the optimal temperature of the reaction is gradually increasing. It may be due to the increase of the auxiliary metal that the number of active sites decreases. Therefore, it can only be achieved by increasing the temperature. Higher activity.

Table 3 Evaluation results of cat26, cat6, cat3, cat7, and cat8

It can be seen from Table 3 that this method is suitable for different contents of USY molecular sieves and its catalytic effect does not change much, but as the content of USY increases, the optimal reaction temperature will gradually decrease, because as the amount of USY increases, the activity The number of sites will also increase, so the required temperature will be lower.

Table 4 Evaluation results of cat9, cat10, cat3, cat11, cat12, cat13, and cat14

Table 5 Evaluation results of cat3, cat15, cat16, cat17, cat18, cat19, cat20

It can be seen from Table 4 and Table 5 that this method is also suitable for other auxiliary metals and other molecular sieves, and its catalytic activity is similar to that of USY molecular sieves. The heterogeneous ratio has been significantly improved.

Table 6 Evaluation results of cat21, cat22, cat23, cat24, cat25/cat26

It can be seen from Table 6 that when the USY molecular sieve is not added, _{the activity of the pure Al 2} O ₃ carrier is weak, and the conversion rate is only 52% at 370°C. Although the jet fuel component is 74%, it is different. The structure ratio is only 0.4, and most of them are n-alkanes. This may be due to the small number of active centers of the catalyst and the high temperature cracking of jet fuel. Al ₂ O _{3 is} directly blended with the catalyst of USY molecular sieve. This catalyst has strong cracking activity. The conversion rate reaches 93% at 280℃, but half of the raw materials are converted into C5-C8 light components and aviation fuel components. Only 43%, probably because the USY molecular sieve has more strong acid sites, resulting in too strong cracking. After processing, the selectivity of jet fuel component of USY can reach 73%. Whether it is USY's amino acid treatment, p-toluenesulfonic acid, or urea, the conversion rate of raw materials can be improved while the selectivity of jet fuel components are improved, and the isomerization ratio of jet fuel components is also increasing. Higher.

Figure 2 shows the comparison of XRD diffraction peaks of different catalysts after reduction. It can be seen from the figure that the diffraction peak (2θ=43.5°) of elemental Ni gradually weakened with the increase of Mg content, but no diffraction peak of Mg or MgO was found, indicating that the addition of Mg is beneficial to increase the dispersion of Ni, and Mg Disperse evenly.

_{Figure 3 shows the H 2} -TPR diagram of cat6, cat7, cat8, cat9, cat10, and cat11, which is the amount of hydrogen consumed by the catalyst in the range of 100-1000°C, and shows its ability to be reduced by hydrogen. Three peaks can be clearly seen in the cat6 chart. The first one is a small weak peak near 380°C. This small NiO may be reduced, and the second is a relatively strong and broad peak near 600°C. It can be attributed to the reduction of NiO particles with a larger particle size. The third weak peak is around 800°C, and this peak indicates the strong interaction between the metal Ni and the support, which makes it difficult to be reduced. With the increase of metal magnesium, there are two obvious changes in the peak shape of _{H 2 -TPR.} First of all, with the increase of magnesium loading, the two peaks near 600℃ and 800℃ gradually shift to the high temperature region. However, in the H ₂ -TPR spectrum, if the peak shifts from low temperature to high temperature, it indicates that the metal oxide The reducibility is reduced, which means that the reduction temperature of NiO is too high and it is more difficult to be reduced. This may be because the presence of Mg strengthens the interaction between NiO and the support, thereby inhibiting the reduction of NiO. In addition, when the loading of Mg reaches the range of 2-8%, the two peaks at 600℃ and 800℃ gradually merge into one large peak, while the peak in the range of 500～900℃ becomes wider and the peak area becomes larger. Significant increase, but in the H2-TPR spectrum, this means that the consumption of hydrogen increases, which means that the dispersion of NiO in the carrier increases, so more H _{2 is} needed to reduce NiO.

_{Figure 4 shows the NH 3} -TPD diagrams of cat6, cat7, cat8, cat9, cat10, and cat11. The integrated area of the peak in the _{NH 3} _{-TPD spectrum represents the analytical amount of NH 3} by the catalyst, and this amount is related to The number of acidic sites of the catalyst is positively correlated, and the temperature corresponding to the peak is also proportional to the strength of acidity, so this spectrum can be used to analyze the acidity of the catalyst and the number of acidic sites. The corresponding peak at low temperature (100-200°C) represents weak acid sites, at moderate temperature (200-400°C), the peaks correspond to medium strong acid sites, and at high temperature (>400°C), the corresponding peaks represent weak acid sites. The peaks indicate strong acid sites. It can be seen from the figure that all samples have a peak around 120°C, which corresponds to a weakly acidic site. As the loading of magnesium on the catalyst increases, the acidity of the catalyst changes somewhat. One is that the peak area of the peak corresponding to the strong acid site at around 470°C is reduced, and the peak moves to the low temperature region, indicating that the number and intensity of the strong acid site are reduced. The other is that the peak and peak area of the peak corresponding to the weak acid site at about 140°C gradually increase, indicating that the number of weak acid sites has increased. Therefore, we can infer that the addition of metal Mg to the catalyst can serve as a mask. Strong acid sites increase the number of weak acid sites, and with the increase of Mg loading, the number and strength of strong acid sites gradually decrease, while the number of weak acid sites gradually increases.

The embodiments of the present invention have been described in detail above, but the content is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. Among them, the experimental methods that do not specify the operating steps are carried out in accordance with the corresponding product instructions. The instruments, reagents, and consumables used in the examples can be purchased from commercial companies unless otherwise specified. All equal changes and improvements made in accordance with the scope of application of the present invention should still fall within the scope of the patent of the present invention.

Claims

An alumina-coated molecular sieve composite carrier is characterized in that it has a core-shell structure, the inner core is a molecular sieve, and the outer shell is alumina, and the inner molecular sieve and the outer shell alumina are connected by p-toluenesulfonic acid groups.
The alumina-coated molecular sieve composite carrier according to claim 1, wherein the molecular sieve has been treated with amino acids in advance;

Preferably, the amino acid is one or more of aspartic acid, glutamic acid, lysine, arginine and histidine;

Preferably, the amino acid is glutamic acid with a mass fraction of 1-5%.
The alumina-coated molecular sieve composite carrier according to claim 1 or 2, wherein the molecular sieve is ZSM-5, Beta, USY, HY, mesoporous Y, rare earth Y, mordenite, SAPO-5, SAPO -11 and SAPO-34 one or more;

Preferably, the molecular sieve is USY.
The method for preparing the alumina-coated molecular sieve composite carrier according to any one of claims 1 to 3, characterized in that it comprises the following steps:

Molecular sieve pretreatment: The molecular sieve is first treated with amino acids, and then the p-toluenesulfonic acid group is grafted onto the molecular sieve to obtain a modified sulfonated molecular sieve;

Preparation of composite carrier: mix the modified sulfonated molecular sieve, aluminum source and urea, and obtain a composite carrier of alumina-coated molecular sieve after crystallization;

Preferably, the aluminum source includes one or more of pseudo-boehmite, aluminum isopropoxide, aluminum acetylacetonate, and aluminate coupling agent;

Preferably it is aluminum isopropoxide;

Preferably, the molar ratio of urea to aluminum source is 0.02-0.1, and the stirring reflux temperature is 25-80°C;

Preferably, the mass percentage of the sulfonated molecular sieve in the composite carrier is 1-20%; preferably 10%;
The method for preparing an alumina-coated molecular sieve composite carrier according to claim 4, wherein the modified sulfonated molecular sieve is added to the alcohol aqueous solution containing cetyltrimethylammonium bromide, and an aluminum source is added. And urea;

Preferably, in the aqueous alcohol solution, the mass ratio of cetyltrimethylammonium bromide is 1-5%, and the mass ratio of ethanol to water is 0.5-2.
The method for preparing an alumina-coated molecular sieve composite carrier according to claim 4, characterized in that the specific process of molecular sieve pretreatment is to add the molecular sieve to the amino acid solution, stir and reflux the reaction, and then re-process the molecular sieve product Put it into the p-toluenesulfonic acid solution, stir and reflux to react to obtain the modified sulfonated molecular sieve;

Preferably, the mass fraction of the amino acid solution is 1-5%, and the mass fraction of the p-toluenesulfonic acid solution is 1-5%;

Preferably, the reflux temperature for two stirrings is 25-80°C.
A hydrocracking isomerization catalyst comprising the alumina-coated molecular sieve composite carrier described in any one of claims 1-3.
The method for preparing the hydrocracking isomerization catalyst according to claim 7, characterized in that the active components are loaded on the composite carrier of alumina-coated molecular sieve by an equal volume impregnation method, and the hydrogenated catalyst is obtained by drying and roasting. Cracking isomerization catalyst.
The method for preparing a hydrocracking isomerization catalyst according to claim 8, wherein the active component includes a main active metal component and an auxiliary metal component;

Preferably, the main active metal component is Pt, Pd or Ni, Co, accounting for 0.5-1% or 5-20% of the catalyst;

Preferably, the promoter metal component is Na, K, Be, Mg, Ca, Sr, Cr, Mn, Fe, Cu, Zn, which accounts for 0.5-10% of the catalyst.
The application of the hydrocracking isomerization catalyst according to claim 7 in hydrocracking isomerization is characterized in that it is used for the hydrogenation of the hydrodeoxygenation products of animal and vegetable fats and oils to prepare bio-biofuels.