54results about How to "Reduce the ratio of silicon to aluminum" patented technology

The invention discloses a ZSM-48 molecular sieve with a low silica-alumina ratio and a preparation method thereof. The molecular sieve has the following properties: the molar ratio of silica to alumina is 25-50; the specific surface is 250-400 m2/g; the pore volume is 0.25-0.35 cm3/g; the average pore size is 3-5 nm. The preparation method comprises the following steps: (1) well mixing a seed crystal S, a template R, a silicon source, an aluminium source, sodium hydroxide and water to prepare a reaction mixture, wherein the composition of the reaction mixture is as follows: on a basis of oxide, the molar ratio of R to SiO2 is 0.05-0.2, the molar ratio of SiO2 to Al2O3 is 30-50, the molar ratio of Na2O to SiO2 is 0.06-0.1, the molar ratio of H2O to SiO2 is 15-23, the mass ratio of S to SiO2 is 0.05-0.5, S is the ZSM-48 molecular sieve, and R is 12-crown ether-4; (2) performing hydrothermal crystallization of the reaction mixture prepared in step (1) at 150-170 DEG C for 4-8 days, performing filtration, washing, drying, and roasting of the crystallization product to obtain the ZSM-48 molecular sieve with a low silica-alumina ratio. The ZSM-48 molecular sieve prepared by the method of the invention has a low silica-alumina ratio, and has good application prospects in technical fields of isodewaxing and the like.

The invention discloses a preparation method for a low silicon-aluminum ratio nanosheet flower cluster-like mordenite molecular sieve. The preparation process of the mordenite molecular sieve includes: dissolving an aluminum source and an alkali source in deionized water, adding silica sol into the obtained clarified solution to obtain a uniform white colloid, transferring the white colloid into a reaction kettle to undergo hydrothermal reaction, thus obtaining the low silicon-aluminum ratio nanosheet flower cluster-like mordenite molecular sieve. The mordenite molecular sieve prepared by the invention has the advantages of wide silicon source and aluminum source, low silicon-aluminum ratio, multiple active centers, no adding of any surfactant, low preparation cost, less environmental pollution and large specific surface area, and is conducive to spread of the reactants and product and acceleration of the reaction rate, thus being widely applicable in adsorption, separation, catalytic cracking, isomerization and other fields.

The invention discloses a ZSM-48/Silicalite-1 composite molecular sieve and a preparation method thereof, the composite molecular sieve takes the ZSM-48 molecular sieve with low silica-alumina ratio as a shell phase, and takes Silicalite-1 as a core layer, total specific surface area of the composite molecular sieve is 330-400m<2>/g, the total pore volume is 0.22-0.28ml/g, average aperture is 2.5-3.5nm, by measuring gross weight of the composite molecular sieve, the shell layer content is 10-70%; wherein, mol ratio of silicon oxide of the ZSM-48 molecular sieve with low silica-alumina ratio to alumina is 25-50. The preparation method comprises the following steps: uniformly mixing the ZSM-48 molecular sieve with low silica-alumina ratio, sodium hydroxide, a template and water, adding silicon source to prepare a reaction mixture gel system, crystallizing the reaction mixture gel, separating the crystallization products, drying, and roasting to obtain the ZSM-48/Silicalite-1 composite molecular sieve. The composite molecular sieve has good shape-selecting performance and anti-carbon deposition capability, and has latent industrial application value in alkylation and isomerization reactions.

The invention discloses a method for synthesizing large-grain and highly-dispersed 4A zeolite. The method comprises the following steps of: preparing materials, gelatinizing, crystallizing, washing, and drying. In order to synthesize the large-grain and highly-dispersed 4A zeolite, a certain silicon-to-aluminum ratio is kept, a water-to-sodium ratio is properly increased, and a relatively low sodium-to-silicon ratio is controlled in the aspect of a raw material ratio; in order to ensure that grains are large and uniform, N-atom-containing organic alkali or an anionic surfactant is properly added into ingredients; in order to synthesize a 4A molecular sieve with large grains and high dispersibility, two-section crystallization is adopted, the first section is dynamic crystallization, the temperature is controlled to be between 70 and 85 DEG C to control the number of grain seeds and achieve a high dispersion degree among the seeds, and the second section is static crystallization to create conditions for grain growth only; and a certain amount of builder is added at the late stage of washing, so that the pH value of raw powder of the molecular sieve can be reduced, and bonded ions can be neutralized due to weak acidity and enter a solution to meet the requirement of dispersibility.

The invention discloses a USY molecular sieve with double meso-structures. The volume of pores with pore sizes of 3 to 5 nm in the USY molecular sieve accounts for 15 to 40% of the total pore volume of the USY molecular sieve; the volume of pores with pore sizes of 7 to 10 nm accounts for 25 to 50% of the total pore volume of the USY molecular sieve; a mol ratio of silicon oxide to alumina in the molecular sieve is in a range of 7 to 15; and the USY molecular sieve has a specific surface area of 680 to 980 m<2>/g, a pore volume of 0.42 to 0.75 ml/g and an average pore size of 1.9 to 3.1 nm. The USY molecular sieve prepared in the invention has meso pores of two pore sizes, can provide more reaction space for large molecules and has improved catalysis performance.

The invention discloses a modified Y type molecular sieve and a preparation method thereof. The molecular sieve has the following properties: the total pore volume is 0.76-1.25ml/g, wherein the mesoporous volume is 0.55-1.05ml/g and the mesoporous volume is 65-90% of the total pore volume; the mole ratio of silicon oxide to aluminum oxide is 10-35; and the specific surface area is 680-1050m<2>/g. The preparation method comprises the following steps: under a stirring condition, adding the Y type molecular sieve into a pressure container filled with organic aqueous alkali; closing the system; increasing the pressure to 0.2-1.0MPa, and then increasing temperature to 50-90 DEG C and treating for 0.5-3 hours under constant temperature; and relieving pressure, performing suction filtration, drying and roasting, thereby acquiring the modified Y type molecular sieve. The molecular sieve has larger-size mesoporous distribution and can supply much more reaction space for macromolecules; the catalytic performance of the molecular sieve is promoted; and the preparation method is simple and is suitable for industrial application.

The invention relates to a low-silicon multistage structure ZSM-5 zeolite molecular sieve, and a preparation method and application thereof. The low-silicon multistage structure ZSM-5 zeolite molecular sieve is provided with a micropore-mesoporous multistage structure, wherein a one-time particle size is smaller than 300nm, and a secondary accumulation particle size is 300nm-4mu m; the silica-alumina ratio of the ZSM-5 zeolite molecular sieve is 10-80, the outer superficial area is greater than 100m<2>/g, mesoporous volume is not smaller than 0.1cm<3>/g, and total acid content is greater than1.5mmol/g. The low-silicon multistage structure ZSM-5 zeolite molecular sieve is high in acid content and reaction activity, more mesoporouses enable a reactant or products to be quickly diffused, side reaction and carbon deposition generation can be reduced, the carbon containing ability of the molecular sieve is increased, and the service life of the molecular sieve is prolonged.

The invention discloses a method for preparing a hydro-cracking catalyst composition. The method comprises the following steps: 1, modified Y type molecular sieve, amorphous silica-alumina and/or aluminum oxide are well mixed according to a certain ratio; dilute nitric acid is added, such that a slurry is formed; extrusion molding is carried out; and drying and roasting are carried out, such that a silica-alumina carrier containing the modified Y type molecular sieve is obtained; and 2, the carrier obtained in the step 1 is impregnated with an impregnation solution containing active metals; after impregnation, the carrier is dried and the dried carrier is roasted, such that the hydro-cracking catalyst is obtained. A preparation method of the modified Y type molecular sieve comprises the following steps: NaY zeolite is adopted as raw powder; ammonium salt ion exchange, ammonium fluorosilicate dealumination and silicon reinsertion treatment, hydrothermal treatment, and aluminum salt solution treatment are carried out; impregnation is carried out in organic solvents; and fast drying, alkali desilication, drying and roasting treatments are carried out, such that the modified Y type molecular sieve is obtained. The hydro-cracking catalyst composition provided by the invention has good temperature increase sensitivity and operation flexibility. The composition can be widely used in hydro-cracking reaction processes.

The invention discloses an NU-87 molecular sieve and a preparation method thereof. The method comprises a preparation process of a crystallization material, a crystallization process and a recovery and treatment process of a crystallization product, wherein in the preparation process of the crystallization material, an aluminum source, a silicon source, alkali, a template agent, inorganic salt, an EU-1 molecular sieve and water are mixed; and the mass ratio of the EU-1 molecular sieve fed into the crystallization material to SiO2 contained in other components is 0.1-0.4. The NU-87 molecular sieve prepared by the method has the advantages of low silicon-aluminum ratio, high pore volume, low cost, and the like.

The invention relates to a low-silicon-aluminum-ratio ZSM-12 type zeolite molecular sieve synthesis method. In the prior art, the templating agent for synthesizing the low-silicon-aluminum-ratio ZSM-12 type zeolite molecular sieve has low feasibility, and the obtained ZSM-12 type zeolite molecular sieve has more impurities. A purpose of the present invention is mainly to solve the problems in theprior art. According to the technical scheme, the method comprises: uniformly mixing a silicon source, an aluminum source, a templating agent Q and water according to a molar ratio of SiO2 to Al(OH)3to the templating agent Q to H2O of 1:(0.02-0.2):(0.1-2.0):(30-200) to obtain a mixture, carrying out hydrothermal crystallization on the mixture for 20-200 h at a temperature of 95-180 DEG C, washingthe obtained product, and drying to obtain the low silicon-aluminum-ratio ZSM-12 type zeolite molecular sieve. With the technical scheme, the problem in the prior art can be well solved. The obtainedproduct of the present invention can be used in industrial catalytic applications.