Pseudo-boehmite, method for preparing the same, catalytic cracking catalyst containing the pseudo-boehmite, and preparation and application thereof

Abstract

The present invention provides pseudo-boehmite. The ratio of the particle size D (020) to the particle size D (130) is D (130) / D (020) = 1.0 to 1.5, preferably 1.1 to 1.3. The present invention also provides a method for preparing the pseudo-boehmite, a catalytic cracking catalyst containing the pseudo-boehmite, and a method for preparing and using the catalytic cracking catalyst. The pseudo-boehmite is used in a catalytic cracking catalyst and can generate an obvious mesopore distribution under the condition that the catalyst strength reaches the standard, significantly improving the pore structure of the catalyst, which is of great significance from the perspective of promoting the efficient diffusion of heavy oil macromolecules, reaction intermediates and product molecules in the catalyst, reducing the coke yield and optimizing the product distribution. The method for preparing the pseudo-boehmite is pollution-free, environmentally friendly, low-cost and easy to implement.

Description

Detailed Description of the Invention

[0001] 〔Technical Field〕 The present invention relates to pseudo-boehmite and a method for preparing the same, and further relates to a heavy oil catalytic cracking catalyst containing pseudo-boehmite, and methods for preparing and applying the same.

[0002] 〔Background Art〕 Catalytic cracking is an important method for heavy oil treatment. Currently used catalytic cracking catalysts generally contain molecular sieves and matrix materials. Alumina matrix is widely used due to its excellent heavy oil cracking ability. The commonly used alumina matrix material is pseudo-boehmite, which is widely used in petroleum refining and petrochemical catalysts, and is often used as a binder for catalytic cracking catalysts and a precursor for hydrogenation catalyst supports (γ-Al2O3). Pseudo-boehmite has good binding properties after acidification and can be used as a binder for catalytic cracking catalysts, and can also form a certain mesoporous structure after the catalyst is prepared and formed.

[0003] The chemical formula of pseudo-boehmite is AlOOH·nH2O (0 < n < 1, particularly 0.08 to 0.62), which is an aluminum oxide compound with a higher water content and a smaller crystal size than boehmite. Pseudo-boehmite is a crystal phase that is easily formed during the synthesis of aluminum hydroxide, with incomplete crystallization, and the typical crystal form is very thin and wrinkled lamellae.

[0004] There are many methods for preparing pseudo-boehmite, mainly including the aluminum alcoholate hydrolysis method and the precipitation method. The precipitation method can be divided into two categories: the acidic method and the alkaline method.

[0005] The aluminum alcoholate hydrolysis method uses metallic aluminum and higher alcohols (n-pentanol, n-hexanol, isopropanol) as raw materials, reacts metallic aluminum with alcohol in the presence of a catalyst to form aluminum alcoholate, and then hydrolyzes it to obtain boehmite. However, this method has high manufacturing costs and a complex manufacturing process.

[0006] The alkali precipitation method refers to a method of preparing boehmite by neutralizing and precipitating an acidic aluminum salt with an alkali; generally used aluminum salts include Al2(SO4)3, Al(NO3)3, AlCl3, etc., and generally used alkali precipitants include NaOH, NH3·H2O, NaAlO2, Na2CO3, etc.

[0007] The acid precipitation method refers to a method of preparing boehmite by neutralizing and precipitating an aluminate with an acid. The aluminate is generally sodium aluminate. The acid used can be a strong acid (HNO3, H2SO4, etc.), a weak acid (NH4HCO3, NaHCO3, etc.), or CO2, etc. Among these, the NaAlO2-CO2 method is also called the carbonization method. The carbonization method for preparing boehmite can utilize the manufacturing process of alumina by the sintering method, using the intermediate product NaAlO2 solution and the waste gas CO2 discharged from the aluminum factory as reaction raw materials. The process is simple, and by-products and waste liquids generated in the manufacturing process can be returned to the alumina manufacturing process for reuse; it is the method with the lowest cost for industrially manufacturing boehmite.

[0008] The pseudo-boehmite prepared by the conventional carbonization method has low crystallinity and a most probable pore diameter of only 3.8 nm. When this is prepared into a catalytic cracking catalyst, only a mesopore structure with a pore diameter of 3.8 nm can be obtained. After acidifying the existing pseudo-boehmite, the pore diameter of the prepared catalytic cracking catalyst is likely to be 4.5 nm or less, and it is difficult to form a pore structure with a pore diameter larger than that. The molecular size of the raw material for catalytic cracking is relatively large, and diffusion within pores with a diameter of 3.8 nm or 4.5 nm is significantly hindered. Due to this hindrance effect, the efficient diffusion and conversion of heavy oil raw material molecules are restricted, which does not lead to a reduction in coke yield and an improvement in product distribution.

[0009] CN110304644A discloses a method for producing high-purity and high-viscosity pseudo-boehmite by carbonization. This method involves pre-decomposing and purifying a sodium aluminate solution to produce a high-purity sodium aluminate solution, and reacting this sodium aluminate solution with carbon dioxide gas to obtain high-purity pseudo-boehmite. However, this pseudo-boehmite has a small most probable pore diameter and the pore diameter cannot be increased in the process of preparing a catalytic cracking catalyst.

[0010] The catalytic cracking catalyst prepared from existing pseudo-boehmite has low coke selectivity. Currently, there is no literature report that applying pseudo-boehmite prepared by the carbonization method after acidification and peptization can provide a larger most probable pore diameter distribution.

[0011] 〔Summary of the Invention〕 The first technical problem to be solved by the present invention is to provide a pseudo-boehmite that can generate a larger mesopore structure after acidification.

[0012] The second technical problem to be solved by the present invention is to provide a method for preparing pseudo-boehmite.

[0013] The third technical problem to be solved by the present invention is to provide a catalytic cracking catalyst, which contains pseudo-boehmite having specific crystal characteristics and has a low coke yield when used in a catalytic cracking reaction.

[0014] The fourth technical problem to be solved by the present invention is to provide a preparation method and an application method of a catalytic cracking catalyst.

[0015] Specifically, the present invention provides the following three sets of technical solutions A, B, and C: A1. Pseudo-boehmite having a crystal size D (130) = 4 nm to 10 nm and D (130) / D (020) being 1.0 to 1.5.

[0016] A2. The pseudo-boehmite according to technical solution A1, wherein the most probable pore diameter of the pseudo-boehmite is more than 4.5 nm and not more than 12 nm, for example, 4.8 nm to 11 nm; preferably, the most probable pore diameter is 5 nm to 10 nm.

[0017] A3. The pseudo-boehmite according to technical solution A1 or A2, wherein D (130) / D (020) is 1.1 to 1.3.

[0018] A4. The pseudo-boehmite according to technical solution A1, A2, or A3, wherein the peptization index of the pseudo-boehmite is 90% to 100%, for example, the peptization index is 93% to 99%; the crystallinity of the pseudo-boehmite is 85% to 110%, for example, the crystallinity of the pseudo-boehmite is 88% to 108%; the pore volume of the pseudo-boehmite is 0.3 cm 3 / g to 0.58 cm 3 / g, for example, 0.31 cm 3 / g to 0.52 cm 3 / g.

[0019] A5. A method for preparing pseudo-boehmite, comprising the following steps: (1) A step of reacting a sodium aluminate solution with CO2 to form a first slurry; (2) A step of aging the first slurry under certain conditions to obtain an aged slurry; The aging under certain conditions includes first static aging and then aging under stirring, and the temperature of the aging is above 100 °C and below 185 °C, the step; (3) A step of filtering, washing, and drying the aged slurry.

[0020] A6. In step (1), the concentration of the sodium aluminate solution is 5 g / L to 60 g / L in terms of Al2O3; and, The pH value at the end point of the reaction between the sodium aluminate solution and CO2 is 8.5 to 10.5, the method according to technical solution A5.

[0021] A7. In step (1), the reaction conditions between the sodium aluminate solution and CO2 include that the starting temperature of the reaction is 10 °C to 35 °C, a CO2-containing gas with a CO2 concentration of 20% by volume to 100% by volume is introduced into the sodium aluminate solution for reaction, and the end temperature of the reaction is preferably 15 °C to 55 °C, the method according to technical solution A5 or A6.

[0022] A8. In the step (2), the temperature of the aging of the slurry is 120 °C to 180 °C, the pressure of the aging is 0.2 MPa to 1 MPa, and the time of the aging is 2 hours to 10 hours, the method according to technical solution A5, A6, or A7.

[0023] A9. The time of the static aging in the step (2) is 1 hour to 4 hours, for example, 2 hours to 3 hours, and the time of the aging under stirring is 1 hour to 6 hours, the method according to technical solution A5 or A8.

[0024] A10. The temperature of the aging is 135°C to 180°C, and the aging is preferably aging at a constant temperature, and the method according to technical solution A5, A6, A7, A8, or A9.

[0025] A11. The stirring speed of the aging under stirring is 50 r / min to 400 r / min, and the method according to technical solution A5, A6, A7, or A8.

[0026] A12. Use of the pseudo-boehmite according to any one of technical solutions A1 to A4 in the preparation of the catalyst.

[0027] B1. 10% to 50% by weight of Y-type molecular sieve on a dry basis, 0 to 40% by weight of other molecular sieves on a dry basis, 10% to 40% by weight of pseudo-boehmite having specific crystal properties in terms of alumina conversion, 3% to 20% by weight of a binder in terms of oxide conversion, and 10% to 80% by weight of clay on a dry basis; the pseudo-boehmite having specific crystal properties has D (130) / D (020) = 1 to 1.5, D (130) = 4 nm to 10 nm, where D (130) represents the crystal size of the crystal plane represented by the (130) peak of the XRD spectrum of the pseudo-boehmite crystal, and D (020) represents the crystal size of the crystal plane represented by the (020) peak of the XRD spectrum of the pseudo-boehmite crystal, a catalytic cracking catalyst.

[0028] B2. The pore volume of the pseudo-boehmite having specific crystal properties is 0.3 cm 3 / g to 0.58 cm 3 / g, the most probable pore diameter is more than 4.5 nm to 12 nm, and the peptization index is 90% to 100%, and the catalytic cracking catalyst according to technical solution B1. Preferably, the pseudo-boehmite has a pore diameter of 5 nm to 10 nm, a crystallinity of 85% to 110%, and D of the pseudo-boehmite having specific crystal properties (130) / D (020)is preferably from 1.1 to 1.3; the other molecular sieve is preferably at least one of MFI structure zeolite, beta zeolite, and non-zeolite molecular sieve, the catalytic cracking catalyst according to technical solution B1.

[0029] B3. The Y-type molecular sieve is at least one of REY, REHY, DASY, SOY, PSRY, HSY, and HRY; the other molecular sieve is at least one of HZSM-5, ZRP, and ZSP, the catalytic cracking catalyst according to technical solution B1.

[0030] B4. The pseudo-boehmite having specific crystal properties has a D of 6.5 nm to 8.2 nm, for example, 7.8 nm to 8.2 nm (130) , a D of 1.22 to 1.29 (130) / D (020) , and a most probable pore diameter of 7.4 nm to 8.5 nm, for example, 7.8 nm to 8.5 nm, the catalytic cracking catalyst according to any one of technical solutions B1 to B3.

[0031] B5. The most probable pore diameter of the catalytic cracking catalyst is 3.5 nm to 4 nm and 4.5 nm to 10 nm, the catalytic cracking catalyst according to any one of technical solutions B1 to B4.

[0032] B6. A method for preparing a catalytic cracking catalyst, comprising the following steps: A step of preparing pseudo-boehmite having specific crystal properties, A step of forming a slurry containing the pseudo-boehmite having specific crystal properties, a Y-type molecular sieve, optionally another molecular sieve, a binder, clay, and water, and A step of spray drying.

[0033] B7. The method for preparing the pseudo-boehmite having specific crystal properties according to technical solution B6, the method comprising the following steps: (1) A step of reacting a sodium aluminate solution with CO2 to produce a first slurry; (2) Aging the first slurry under certain conditions to form a second slurry; The aging under certain conditions includes first static aging and then aging with stirring, and the temperature of the aging is above 100 °C and below or equal to 185 °C, a step; (3) Filtering, washing, and drying the second slurry to obtain boehmite having specific crystal characteristics.

[0034] B8. In step (1), the Al2O3 concentration of the sodium aluminate solution is 5 g / L to 60 g / L; and the pH value at the end point of the reaction between the sodium aluminate solution and CO2 is 8.5 to 10.5. The method according to technical solution B7.

[0035] B9. In step (1), the reaction conditions between the sodium aluminate solution and CO2 include that the starting temperature of the reaction is 10 °C to 35 °C, a CO2-containing gas with a CO2 concentration of 20% by volume to 100% by volume is introduced into the sodium aluminate solution to carry out the reaction, and the end temperature of the reaction is preferably 15 °C to 55 °C. The method according to technical solution B7 or B8.

[0036] B10. The pressure of the aging is 0.2 MPa to 1 MPa, and the time of the aging is 2 hours to 10 hours; preferably, the time of the static aging in step (2) is 1 hour to 4 hours, for example, 2 hours to 3 hours, and the time of the aging with stirring is 1 hour to 6 hours. The method according to technical solution B7, B8, or B9.

[0037] B11. The temperature of the aging is 135 °C to 180 °C, the aging is preferably aging at a constant temperature, and the stirring speed of the aging with stirring is preferably 50 r / min to 400 r / min. The method according to technical solution B10.

[0038] B12. The cleaning condition in step (3) is to clean with deionized water at 70°C to 100°C until the pH value of the wet filter cake reaches 7 to 7.5; and the drying in step (3) is carried out at a drying temperature of 70°C to 98°C. The method according to technical solution B7, characterized in that.

[0039] B13. The method for preparing the catalytic cracking catalyst according to technical solution B6, characterized in that it includes the following: A step of slurrying pseudoboehmite having specific crystal properties with water to form a pseudoboehmite slurry, wherein the solid content is preferably 5% by weight to 25% by weight. A step of adding hydrochloric acid, wherein the mass ratio of HCl to pseudoboehmite having specific crystal properties, calculated as alumina, is 0.037 to 0.104, and the concentration of hydrochloric acid can be 10% by weight to 37% by weight. Next, a step of mixing it with a slurry containing Y-type molecular sieve, optionally other molecular sieves, binder, clay, and water to obtain a colloidal slurry, wherein the solid content of the slurry is preferably 20% by weight to 40% by weight. A step of spray-drying the colloidal slurry; and Optionally, a step of washing and drying.

[0040] B14. A catalytic cracking method including a step of contacting and reacting a heavy oil with a catalytic cracking catalyst under FCC conditions, wherein the catalytic cracking catalyst is the catalytic cracking catalyst described in any one of technical solutions B1 to B5, or the catalytic cracking catalyst obtained by any one of technical solutions B6 to B13; and the FCC conditions are, for example, the reaction temperature is 480°C to 530°C, the reaction time is 1 to 10 seconds, and the weight ratio of the catalyst to the oil is 3 to 20:1. The catalytic cracking method, characterized in that.

[0041] C1. The crystal size D of pseudoboehmite (130) and D (020) The ratio of is D (130) / D(020) Pseudoboehmite, characterized in that = 1.0 to 1.5, preferably 1.1 to 1.3.

[0042] C2. The crystal size D is measured by powder X-ray diffraction (XRD), The crystal size D is calculated by Scherrer's formula

[0043]

Number

[0044] and is where K = 1.075, λ is the wavelength of the anode radiation Kα1 spectral line, β is the full width at half maximum (unit: radian) of a specific diffraction peak of pseudoboehmite, and θ is the Bragg diffraction angle (unit: degree) of the diffraction peak, D (130) represents the crystal size of the sample perpendicular to the (130) crystal plane,

[0045]

Number

[0046] β 130 is the full width at half maximum of the (130) diffraction peak of the sample (corresponding to 2θ = 38.3°); D (020) represents the crystal size of the sample perpendicular to the (020) crystal plane,

[0047]

Number

[0048] β 020 is the full width at half maximum of the (020) diffraction peak of the sample (corresponding to 2θ = 14.1°), and the pseudoboehmite according to any one of the above technical solutions of the C series.

[0049] C3. The molecular formula of the pseudo-boehmite is AlOOH·nH2O, where n = 0.08 to 0.62, and its crystal size D (130) is 10 nm or less, and the pseudo-boehmite according to any one of the technical solutions of the above C series is characterized thereby.

[0050] C4. The crystal size of the pseudo-boehmite is D (130) = 4 nm to 10 nm, preferably 6.5 nm to 8.2 nm, or 7.8 nm to 8.2 nm, and the pseudo-boehmite according to any one of the technical solutions of the above C series is characterized thereby.

[0051] C5. The pseudo-boehmite has a most probable pore diameter of more than 4.5 nm and 12 nm or less, for example, 4.8 nm to 11 nm, or 5 nm to 10 nm, and the pseudo-boehmite according to any one of the technical solutions of the above C series is characterized thereby.

[0052] C6. The pseudo-boehmite has a crystallinity of 85% to 110%, for example, 88% to 108%, and the pseudo-boehmite according to any one of the technical solutions of the above C series is characterized thereby.

[0053] C7. The peptization index of the pseudo-boehmite is 90% to 100%, for example, 93% to 99%, and the pseudo-boehmite according to any one of the technical solutions of the above C series is characterized thereby.

[0054] C8. The pore volume of the pseudo-boehmite is 0.3 cm 3 / g to 0.58 cm 3 / g, for example, 0.31 cm 3 / g to 0.52 cm 3 / g, and the pseudo-boehmite according to any one of the technical solutions of the above C series is characterized thereby.

[0055] C9. A method for preparing pseudo-boehmite, comprising the following steps: (1) A step of reacting a sodium aluminate solution with CO2 to form a first slurry; (2) Ripen the first slurry under certain conditions to obtain a ripened slurry; The ripening under certain conditions includes first static ripening and then ripening under stirring, and the temperature of the ripening is above 100 °C and below 185 °C, step; (3) Filter, wash, and dry the ripened slurry.

[0056] C10. In step (1), the concentration of the sodium aluminate solution is 5 g / L to 60 g / L in terms of Al2O3; and the pH value at the end point of the reaction between the sodium aluminate solution and CO2 is 8.5 to 10.5. The method for preparing pseudo-boehmite according to any one of the above C-series technical solutions.

[0057] C11. In step (1), the reaction conditions between the sodium aluminate solution and CO2 include that the starting temperature of the reaction is 10 °C to 35 °C, the CO2 concentration is 20% by volume to 100% by volume of a CO2-containing gas (the balance is an inert gas such as nitrogen), the CO2-containing gas is introduced into the sodium aluminate solution to carry out the reaction, and the end temperature of the reaction is preferably 15 °C to 55 °C. The method for preparing pseudo-boehmite according to any one of the above C-series technical solutions.

[0058] C12. In step (2), the temperature of the ripening of the slurry is 120 °C to 180 °C, the pressure of the ripening is 0.2 MPa to 1 MPa, and the time of the ripening is 2 hours to 12 hours, for example, 2 hours to 10 hours. The method for preparing pseudo-boehmite according to any one of the above C-series technical solutions.

[0059] C13. The time of the static ripening in step (2) is 1 hour to 8 hours, for example, 2.5 hours to 7 hours, or 1 hour to 4 hours, for example, 2 hours to 3 hours, and the time of the ripening under stirring is 1 hour to 6 hours. The method for preparing pseudo-boehmite according to any one of the above C-series technical solutions.

[0060] C14. The temperature of the aging is 135°C to 180°C, and the aging is preferably aging at a constant temperature. The method for preparing pseudo-boehmite according to any one of the technical solutions in the above C series.

[0061] C15. The stirring speed of the aging under stirring is 50 r / min to 450 r / min, preferably 100 r / min to 400 r / min. The method for preparing pseudo-boehmite according to any one of the technical solutions in the above C series.

[0062] C16. In the step (2), The conditions of the static aging include that the temperature is 120°C to 180°C, preferably 135°C to 180°C, the pressure is 0.2 MPa to 1 MPa, the time is 1 hour to 8 hours, for example, 2.5 hours to 7 hours, and the stirring speed is 100 r / min to 450 r / min; The conditions of the aging under stirring include that the temperature is 120°C to 180°C, preferably 135°C to 180°C, the pressure is 0.2 MPa to 1 MPa, and the time is 1 hour to 6 hours, for example, 1 hour to 5 hours; Preferably, the ratio of the time of static aging to the time of aging under stirring is 1 to 5:1, preferably 1.25 to 3:1. The method for preparing pseudo-boehmite according to any one of the technical solutions in the above C series.

[0063] C17. The conditions of the washing in the step (3) are to wash with deionized water at 70°C to 100°C until the pH value of the wet filter cake reaches 7 to 7.5; and the drying in the step (3) is carried out at a drying temperature of 70°C to 98°C. The method for preparing pseudo-boehmite according to any one of the technical solutions in the above C series.

[0064] Use of the pseudo-boehmite according to any one of the technical solutions in the above C series as a catalyst, carrier and binder in the petroleum industry; as a carrier coating for automotive exhaust treatment catalysts in the automotive industry; as an additive for flame retardant materials in the fire protection field; as an ink absorption coating agent for high-grade inkjet printing paper in the paper industry; as a gas purification adsorbent, drinking water defluorination agent, industrial wastewater decolorization and deodorization agent in the environmental protection industry; as a coating additive in the construction industry; and as a reinforcing material in ceramic composite materials.

[0065] C19. Containing 10% to 50% by weight of Y-type molecular sieve on a dry basis, 0% to 40% by weight of other molecular sieves on a dry basis, 10% to 40% by weight of the pseudo-boehmite according to any one of the technical solutions in the above C series in terms of alumina, 3% to 20% by weight of binder in terms of oxide, and 10% to 80% by weight of clay on a dry basis; Preferably, the other molecular sieve is one or more of MFI structure zeolite, beta zeolite, and non-zeolite molecular sieve; more preferably, the other molecular sieve is one or more of HZSM-5, ZRP, and ZSP; and / or, Preferably, the Y-type molecular sieve is one or more of REY, REHY, DASY, SOY, PSRY, HSY, and HRY. Catalytic cracking catalyst.

[0066] C20. A method for preparing the catalytic cracking catalyst according to any one of the technical solutions in the above C series, comprising the following steps: A step of preparing the pseudo-boehmite according to any one of the technical solutions in the above C series, A step of forming a slurry containing the pseudo-boehmite, Y-type molecular sieve, optionally other molecular sieves, binder, viscosity and water, and A step of spray drying.

[0067] A method for preparing a catalytic cracking catalyst according to any one of the above C-series technical solutions, characterized by comprising the following steps: A step of slurrying the pseudo-boehmite according to any one of the above C-series technical solutions with water to form a pseudo-boehmite slurry, wherein the solid content is preferably 5 wt% to 25 wt%; A step of adding hydrochloric acid, wherein the mass ratio of HCl to the pseudo-boehmite calculated as alumina is 0.037 to 0.104, and the concentration of hydrochloric acid can be 10 wt% to 37 wt%; Next, a step of mixing a slurry containing Y-type molecular sieve, optionally other molecular sieves, binder, clay, and water to obtain a colloidal slurry, wherein the solid content of the slurry is preferably 20 wt% to 40 wt%; A step of spray drying; and Optionally, a step of washing and drying.

[0068] A catalytic cracking method comprising a step of contacting and reacting a heavy oil with a catalytic cracking catalyst under FCC conditions, wherein the catalytic cracking catalyst is the catalytic cracking catalyst according to any one of the above C-series technical solutions, or a catalytic cracking catalyst obtained by the method for preparing a catalytic cracking catalyst according to any one of the above C-series technical solutions; For example, the FCC conditions include that the reaction temperature is 480 °C to 530 °C, the reaction time is 1 to 10 seconds, and the weight ratio of the catalyst to the oil is 3 to 20:1. A catalytic cracking method characterized by this.

[0069] 〔Detailed Description of the Invention〕 In the present specification, the pressure is gauge pressure unless otherwise specified.

[0070] In the present specification, the content is a value based on wt% unless otherwise specified.

[0071] In the present specification, sodium aluminate and sodium metaaluminate are synonymous and both refer to NaAlO2.

[0072] The present invention relates to pseudo-boehmite, wherein the crystal size D of the pseudo-boehmite (020) with respect to the crystal size D (130) has a ratio of D (130) / D (020) = 1.0 to 1.5, preferably 1.1 to 1.4, or 1.1 to 1.3, or 1.2 to 1.35, or 1.22 to 1.29.

[0073] The crystal size D is measured by powder X-ray diffraction (XRD), and the crystal size D is calculated by Scherrer's formula

[0074]

Number

[0075] where K = 1.075, λ is the wavelength of the anode radiation Kα1 spectral line, β is the half-width (unit: radian) of a specific diffraction peak of pseudo-boehmite, and θ is the Bragg diffraction angle (unit: degree) of the diffraction peak, and D (130) represents the crystal size of the sample perpendicular to the (130) crystal plane,

[0076]

Number

[0077] β 130 is the half-width of the (130) diffraction peak of the sample (corresponding to 2θ = 38.3°); D (020) represents the crystal size of the sample perpendicular to the (020) crystal plane,

[0078]

Number

[0079] β 020is the half-width of the diffraction peak (020) of the sample (corresponding to 2θ = 14.1°).

[0080] The boehmite provided by the present invention has a molecular formula of AlOOH·nH2O, where n = 0.08 - 0.62, and the crystal size D (130) is 10 nm or less.

[0081] The boehmite provided by the present invention has a crystal size D (130) = 4 nm - 10 nm, preferably 5 nm - 8.5 nm, or 5.1 nm - 8.5 nm, or 5.5 nm - 8.5 nm, or 6 nm - 8.2 nm, or 6.5 nm - 8.2 nm, or 7.8 nm - 8.2 nm.

[0082] The boehmite provided by the present invention has a most probable pore diameter of more than 4.5 nm to 12 nm or less, for example, 4.5 nm - 9 nm, or 4.8 nm - 11 nm, or 5 nm - 10 nm, or 5 nm - 9 nm, or 6 nm - 8.5 nm, or 7 nm - 9 nm, or 7.4 nm - 8.5 nm, or 7.8 nm - 8.5 nm. The pore diameter means the diameter.

[0083] The boehmite provided by the present invention has a crystallinity of 85% - 110%, for example, 88% - 108%, or 90% - 105%, or 99% - 105%.

[0084] The boehmite provided by the present invention has a peptization index of 90% - 100%, for example, 93% - 99%.

[0085] The boehmite provided by the present invention has a pore volume of 0.3 cm 3 / g - 0.58 cm 3 / g, for example, 0.31 cm 3 / g - 0.52 cm 3 / g, or 0.33 cm 3 / g - 0.5 cm 3 / g.

[0086] The present invention also provides a method for preparing boehmite, which includes the following steps: (1) A step of reacting a sodium aluminate (or sodium metaaluminate) solution with CO2 to form a first slurry; (2) A step of aging the first slurry under certain conditions to obtain an aged slurry (referred to as the second slurry); Preferably, the aging under certain conditions is first static aging and then aging under stirring, and the temperature of the aging is above 100 °C and below 185 °C, the step; (3) A step of filtering, washing, and drying the aged slurry.

[0087] According to the method for preparing boehmite of the present invention, in the step (1), the concentration of the sodium aluminate solution is preferably 5 g / L to 60 g / L in terms of Al2O3. The sodium aluminate solution can be purchased as a commercial product or prepared according to an existing method. For example, the method for preparing the sodium aluminate solution includes a step of reacting aluminum hydroxide with an alkali solution at a temperature of 90 °C to 120 °C for 1 hour to 4 hours, and a step of diluting so that the concentration of Al2O3 becomes 5 g / L to 60 g / L. The alkali solution is, for example, a sodium hydroxide solution. The causticization rate of the sodium aluminate solution is, for example, 1.0 to 3.2.

[0088] According to the method for preparing boehmite of the present invention, in the step (1), the sodium aluminate solution is brought into contact with CO2 to react. Here, the CO2-containing gas can be introduced into the sodium aluminate solution for the reaction, and the volume concentration of CO2 in the CO2-containing gas is 20 to 100% by volume, for example, 40 to 100% by volume (the balance is an inert gas such as nitrogen).

[0089] According to the method for preparing boehmite of the present invention, in the step (1), the pH value at the end point of the reaction between the sodium aluminate solution and CO2 is 8.5 to 10.5.

[0090] According to the method for preparing pseudo-boehmite of the present invention, in step (1), the starting temperature of the reaction is preferably 10°C to 35°C, and the ending temperature of the reaction is preferably 15°C to 55°C.

[0091] According to the method for preparing pseudo-boehmite of the present invention, in step (1), the sodium aluminate solution is brought into contact with CO2 for reaction, and the reaction time between the sodium aluminate solution and CO2 is preferably 20 to 70 minutes.

[0092] According to the method for preparing pseudo-boehmite of the present invention, in step (1), the reaction conditions between the sodium aluminate solution and CO2 include that the starting temperature of the reaction is 10°C to 35°C, the reaction time is 20 to 70 minutes, and the ending temperature of the reaction is 15°C to 55°C. The pH value at the end point of the reaction between the sodium aluminate solution and CO2 is 8.5 to 10.5. Preferably, the sodium aluminate solution is reacted with CO2 by bringing the sodium aluminate solution into contact with a CO2-containing gas, where the CO2 volume concentration in the CO2-containing gas is 20% to 100% (the balance is an inert gas such as nitrogen).

[0093] According to the method for preparing pseudo-boehmite of the present invention, in step (2), the first slurry is aged under specific conditions. In one embodiment, the aging temperature is 100°C to 185°C, for example 120°C to 180°C, preferably 135°C to 180°C. The first slurry can be heated to 100°C to 185°C, preferably 120°C to 180°C, or 135°C to 180°C, and then aged at this temperature. Preferably, the time for the first slurry to rise from the reaction ending temperature to the aging temperature does not exceed 60 minutes. Preferably, the temperature from the start of aging to the end of aging is carried out at a constant temperature. The constant-temperature aging means controlling so that the temperature of static aging and the temperature of aging under stirring basically do not change. For example, the difference between the temperature of static aging and the temperature of aging under stirring is preferably 2°C or less.

[0094] According to the method for preparing pseudo-boehmite of the present invention, in step (2), the aging pressure is preferably 0.2 MPa to 1 MPa.

[0095] According to the method for preparing pseudo-boehmite of the present invention, in step (2), the stirring speed is controlled to be 50 r / min to 400 r / min. Stirring can be carried out by an existing stirring method. By stirring, the aging slurry rotates in an aging kettle driven by a stirring paddle.

[0096] According to the method for preparing pseudo-boehmite of the present invention, in step (2), the aging time is 2 hours to 12 hours, for example, 2 hours to 10 hours.

[0097] According to the method for preparing pseudo-boehmite of the present invention, in step (2), first, the slurry is allowed to age statically at a constant temperature, and then aged with stirring. Static aging refers to aging without stirring. Therefore, the slurry is in a static state. For example, the slurry is allowed to stand for a certain period of time. Preferably, the first slurry is first allowed to age statically at the aging temperature for 1 hour to 8 hours, for example, 2.5 hours to 7 hours, 1 hour to 4 hours, for example, 2 hours to 3 hours, and then aged with stirring at the aging temperature for 1 hour to 6 hours. The stirring speed is 50 r / min to 450 r / min, for example, 50 r / min to 400 r / min, or 60 r / min to 400 r / min, or 100 r / min to 400 r / min.

[0098] According to the method for preparing pseudo-boehmite of the present invention, in step (2), the first slurry is aged under certain conditions. The aging temperature is 100 °C to 185 °C, for example, 120 °C to 180 °C, the pressure is 0.2 MPa to 1 MPa, and the aging is carried out by a reaction at a constant temperature for 2 hours to 10 hours; here, the first slurry is first allowed to age statically for 1 hour to 4 hours, for example, 2 hours to 3 hours, and then, while maintaining the aging temperature and pressure, stirring is carried out, and the stirring speed is controlled to be 50 r / min to 400 r / min, for example, 60 r / min to 400 r / min, and the aging time under stirring is 1 hour to 6 hours.

[0099] According to the method for preparing pseudo-boehmite of the present invention, in step (2), the conditions for static aging include a temperature of 120°C to 180°C, preferably 135°C to 180°C, a pressure of 0.2 MPa to 1 MPa, a time of 1 hour to 8 hours, for example, 2.5 hours to 7 hours, and a stirring speed of 100 r / min to 450 r / min; The conditions for aging with stirring include a temperature of 120°C to 180°C, preferably 135°C to 180°C, a pressure of 0.2 MPa to 1 MPa, a time of 1 hour to 6 hours, for example, 1 hour to 5 hours; Preferably, the ratio of the static aging time to the aging time with stirring is 1 to 5:1, preferably 1.25 to 3:1.

[0100] According to the method for preparing pseudo-boehmite of the present invention, in step (2), since the aging temperature is 135°C to 180°C, the catalyst thus obtained can have a more excellent effect of improving the total yield of liquefied gas and gasoline.

[0101] According to the method for preparing pseudo-boehmite of the present invention, in step (3), by filtering, washing, and drying the aging slurry, pseudo-boehmite having specific crystal characteristics and a most probable pore diameter distribution can be obtained. The washing conditions are, for example, washing with deionized water at 70°C to 100°C until the pH of the wet filter cake reaches 7 to 7.5. The drying temperature is preferably 60°C to 98°C, for example, 70°C to 98°C, preferably 70°C to 95°C, and the drying time is, for example, 2 hours to 4 hours.

[0102] The pseudo-boehmite provided by the present invention has specific crystal characteristics, high crystallinity, large crystal size, larger most probable pore diameter, good peptization (the pseudo-boehmite can have a larger most probable pore diameter and good abrasion resistance after peptization), and still has a larger most probable pore diameter even after acidification treatment.

[0103] The method for preparing pseudo-boehmite provided by the present invention is pollution-free, environmentally friendly, low-cost, easy to implement, and can obtain pseudo-boehmite with specific crystal characteristics and the most probable pore diameter distribution. This pseudo-boehmite has high crystallinity, large crystal size, larger most probable pore diameter, and good peptization solubility (the pseudo-boehmite can have a larger most probable pore diameter and good abrasion resistance after peptization), and after acidification treatment, it has a larger most probable pore diameter and good adhesion.

[0104] The pseudo-boehmite provided by the present invention can be used in the preparation of catalysts. Its specific crystal form makes it easy to accumulate pseudo-boehmite to form a stable mesoporous structure when preparing catalysts, and a larger most probable pore diameter can be obtained compared with the prior art. The pseudo-boehmite can be directly acidified without pore expansion treatment to obtain a catalyst with a larger most probable pore diameter, and the catalyst can have good strength. For example, when used in the preparation of a catalytic cracking catalyst, the pseudo-boehmite can generate a significant mesoporous distribution, and a catalytic cracking catalyst with a most probable pore diameter larger than 5 nm can be obtained. While significantly improving the pore structure of the catalyst, the catalyst strength can be maintained at a qualified level. The prepared catalytic cracking catalyst can promote the efficient diffusion of heavy oil macromolecules, reaction intermediates and product molecules in the catalyst, reduce the coke yield, and optimize the product distribution.

[0105] The present invention also provides a catalytic cracking catalyst, which contains 10% to 50% by weight of Y-type molecular sieve based on the dry weight, 0% to 40% by weight of other molecular sieves based on the dry basis, 10% to 40% by weight of pseudo-boehmite according to the present invention based on alumina (for example, 15% to 35% by weight, or 20% to 30% by weight), 3% to 20% by weight of a binder calculated as an oxide, and 10% to 80% by weight of clay based on the dry basis.

[0106] Under the same conditions, the catalytic cracking catalyst prepared using the pseudo-boehmite according to the present invention has a higher yield of liquefied gas and gasoline.

[0107] The catalytic cracking catalyst provided by the present invention contains a Y-type molecular sieve such as one or more of REY, REHY, DASY, SOY, PSRY, HSY, and HRY.

[0108] In the catalytic cracking catalyst provided by the present invention, optionally, other molecular sieves different from the Y-type molecular sieve can also be included. Based on the weight of the catalytic cracking catalyst, on a dry basis, the content of other molecular sieves is, for example, 0 to 40% by weight, or 0 to 30% by weight, or 1% to 20% by weight. Other molecular sieves are, for example, one or more of MFI-structured zeolites, beta zeolites, and non-zeolite molecular sieves. The MFI-structured zeolite is, for example, one or more of HZSM-5, ZRP, and ZSP, the beta zeolite is, for example, Hβ, and the non-zeolite molecular sieve is, for example, one or more of aluminum phosphate molecular sieves (AlPO molecular sieves) and silicon aluminum phosphorus molecular sieves (SAPO molecular sieves). Preferably, it is a molecular sieve having an MFI structure, and the yield of liquefied gas can be further improved.

[0109] The catalytic cracking catalyst provided by the present invention contains clay. The clay is selected from one or more of the clays used as catalytic cracking catalyst components, such as one or more of kaolin, multi-hydrous kaolin (halloysite), montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite, and bentonite. These clays are well known to those skilled in the art. Preferably, the content of clay in the catalytic cracking catalyst provided by the present invention is 10% to 80% by weight on a dry basis, for example, 20% to 55% by weight, or 30% to 50% by weight.

[0110] The catalytic cracking catalyst provided by the present invention contains a binder, and the binder is an alumina binder, and the content of the alumina binder is 3% to 20% by weight, for example, 5% to 15% by weight.

[0111] The alumina binder is preferably an aluminum sol, and the catalytic cracking catalyst contains 3% to 20% by weight, for example, 4% to 10% by weight, or 5% to 15% by weight of the aluminum sol calculated as alumina.

[0112] The catalytic cracking catalyst provided by the present invention has a pore diameter distribution between 3 nm and 4 nm, for example, between 3.5 nm and 4 nm, and also has a significant pore diameter distribution between 4.5 nm and 10 nm, for example, between 5 nm and 9.5 nm or between 6.5 nm and 9 nm, preferably between 7.7 nm and 8.6 nm. Preferably, the catalytic cracking catalyst has a double most probable pore diameter distribution, and the pores with a smaller pore diameter have a most probable pore diameter of 3.5 nm to 4 nm, and the pores with a larger pore diameter have a most probable pore diameter of 4.5 nm to 10 nm, for example, 5 nm to 9.5 nm or 6.5 nm to 9 nm, preferably 7.7 nm to 8.6 nm.

[0113] The present invention also provides a method for preparing the catalyst of the present invention, and the preparation method generally includes the following steps: forming a slurry containing pseudo-boehmite, Y-type molecular sieve, optionally other molecular sieves, binder, clay and water according to the present invention, spray drying, and optionally washing and drying. Spray drying, washing and drying are prior arts and are not particularly required in the present invention. The catalytic cracking catalyst can be prepared according to existing methods, for example, the methods disclosed in Patent CN1098130A and CN1362472A.

[0114] According to a preferred embodiment, the method for preparing a catalytic cracking catalyst includes the following steps: a step of slurrying the boehmite according to the present invention with water to form a boehmite slurry, wherein the solid content of the boehmite slurry is preferably 5 wt% to 25 wt%; a step of then adding hydrochloric acid, wherein the mass ratio of HCl to the boehmite according to the present invention calculated as alumina is preferably 0.037 to 0.104, and the concentration of hydrochloric acid can be 10 wt% to 37 wt%; a step of then mixing it with a slurry containing Y-type molecular sieve, optionally other molecular sieves, binder, clay, and water to obtain a colloidal slurry, wherein the solid content of the slurry is preferably 20 wt% to 40 wt%; a step of spray drying; and optionally, a step of washing and drying.

[0115] The method for preparing a catalytic cracking catalyst provided by the present invention can also include the following steps: a step of preparing the boehmite according to the present invention; a step of forming a slurry containing the boehmite according to the present invention, Y-type molecular sieve, alumina binder, clay, and water; and a step of spray drying.

[0116] The present invention also provides a catalytic cracking method including a step of contacting and reacting heavy oil with the catalytic cracking catalyst provided by the present invention under heavy oil FCC conditions. Here, the heavy oil is one or more of vacuum wax oil, atmospheric residue, vacuum residue, and heavy deasphalted oil, and the FCC conditions are the reaction conditions for the fluid catalytic cracking of heavy oil. Generally, the reaction temperature of the reaction is 480°C to 530°C, the reaction time is 1 to 10 seconds, and the weight ratio of the catalyst to the oil is 3 to 20:1.

[0117] The catalytic cracking catalyst provided by the present invention contains the pseudo-boehmite according to the present invention, has significantly larger mesopores, and can have obvious mesopores with a pore diameter of, for example, 5 nm to 10 nm. It has better diffusion performance for heavy oil molecules, has high accessibility of active centers, and has lower coke selectivity. The catalytic cracking catalyst provided by the present invention is used for the catalytic cracking of heavy oil, has a lower coke selectivity than the existing catalytic cracking catalysts containing conventional pseudo-boehmite, and in a preferred embodiment, can have a higher gasoline yield and liquefied gas yield.

[0118] The preparation method of the catalytic cracking catalyst provided by the present invention does not require increasing the usage amount of other binders. When the catalyst strength is qualified, significantly larger mesopores can be generated. For example, the catalyst can have more mesopores with a pore size exceeding 5 nm, which significantly improves the pore structure of the catalyst and helps to promote the efficient diffusion of heavy oil macromolecules, reaction intermediates, and product molecules in the catalyst. Preferably, the yields of gasoline and liquefied gas can be increased.

[0119] 〔Examples〕 The following examples are used to further illustrate the present invention, but are not intended to limit the present invention.

[0120] In this application, the crystallinity and crystal size D of the sample are measured by powder X-ray diffraction (XRD) using the RIPP139-90 standard method and the RIPP140-90 standard method (see "Petrochemical Analysis Methods" (RIPP Test Methods) edited by Yang Cuiding et al., Science Press, published in 1990).

[0121] The crystallinity of the pseudo-boehmite in the sample is calculated by measuring the integrated intensities of the sample and the standard sample S87-16b (130 crystal plane) at 2θ = 38.3° using the external standard method. The standard sample number is S87-16b, which was prepared by the Institute of Petrochemical Industry and is commercially available. The crystallinity of the pseudo-boehmite in the calibrated sample is 98.0%. The crystallinity of the sample is calculated by the following formula: Crystallinity = Net integrated intensity of the sample / Net integrated intensity of the standard sample × 98.0 The crystal size is calculated by Scherrer's formula

[0122]

Number

[0123] where K = 1.075, λ is the wavelength of the anode radiation Kα1 spectral line, β is the full width at half maximum of a specific diffraction peak of the pseudo-boehmite, and θ is the Bragg diffraction angle of the diffraction peak. D (130) represents the crystal size of the sample perpendicular to the (130) crystal plane,

[0124]

Number

[0125] where β 130 is the full width at half maximum of the (130) diffraction peak of the sample. D (020) represents the crystal size of the sample perpendicular to the (020) crystal plane,

[0126]

Number

[0127] where β 020 is the full width at half maximum of the (020) diffraction peak of the sample.

[0128] In this application, the most probable porosity distribution and pore volume of the sample are determined by the low-temperature nitrogen static volumetric adsorption method, the specific surface area and pore volume are calculated using the two-parameter BET equation, and the pore diameter distribution is calculated using the BJH equation. The pore diameter corresponding to the highest point of the pore diameter distribution curve is the most probable pore diameter of the sample. Using an automatic adsorption device ASAP 2405N V1.01 manufactured by USA Micromeritics, the sample is degassed under vacuum at 1.33×10 -2 Pa and 300 °C for 4 hours, and the adsorption / desorption isotherm of the sample is measured at 77.4 K using N2 as the adsorption medium.

[0129] In this application, determination of the peptization index: Weigh 10 grams of pseudoboehmite, calcine it at 600 °C for 3 hours, place it in a desiccator and cool it. After the temperature drops to room temperature, weigh it to obtain W0 grams, and obtain the dry basis a0 = W0 / 10. Weigh pseudoboehmite with a weight m1 = 6 / a0 grams, put the weighed m1 grams of pseudoboehmite into a 100 mL polytetrafluoroethylene cup, add deionized water up to 40 grams, stir evenly with a magnetic rotor, then add 20 mL of 0.19 N dilute nitric acid solution, stir magnetically for 20 minutes, then pour all the solution into centrifuge tubes, place the centrifuge tubes in a centrifuge, and centrifuge at a speed of 1900 rpm for 20 minutes. Pour out the upper colloidal solution, put it into a weighed crucible, dry it at 80 °C, bake it at 600 °C for 3 hours, place it in a desiccator and cool it. After the temperature drops to room temperature, weigh it to obtain m2 grams, and obtain the peptization index DI = (m2 / 6)*100%.

[0130] The sodium aluminate used in the examples is manufactured by Shanghai Macklin Biochemical Technology Co., Ltd. and has a causticization rate of 1 and analytical purity.

[0131] (Example 1) A sodium aluminate solution with a concentration of 20 g Al2O3 / L was reacted with carbon dioxide having a volume fraction of 40% (the volume fraction of carbon dioxide was 40% and the remainder was nitrogen) to form a gel, and the end point pH value was controlled to 9.5. The resulting slurry was transferred to an aging kettle and allowed to stand and age at 135 °C and 0.35 MPa for 3 hours. Stirring was started under these temperature and pressure conditions, the stirring speed was maintained at 150 r / min, and aging was continued for 1 hour. After aging, the resulting slurry was subjected to solid-liquid separation, and using deionized water at 85 °C, it was continuously washed for 30 minutes until the pH value of the wet filter cake reached 7.1, and a wet filter cake of pseudo-boehmite with impurities removed was obtained. This wet filter cake was dried at 80 °C for 3 hours and pulverized to obtain pseudo-boehmite powder SP1, and its physicochemical properties are shown in Table 1.

[0132] 714.5 g of an aluminum sol with an alumina content of 21% by weight was added to 1565.5 g of deionized water, stirring was started, 2763 g of kaolin with a solid content of 76% by weight was added, and dispersed for 60 minutes to obtain a dispersed kaolin slurry. 2049 g of SP1 pseudo-boehmite with an alumina content of 61% by weight was added to 8146 g of deionized water, and 210 ml of hydrochloric acid with a mass concentration of 36% was added under stirring. After acidification for 60 minutes, the dispersed kaolin slurry was added, and then 1500 g (dry basis) of crushed molecular sieves (HSY-12 molecular sieve and ZSP-3 molecular sieve, the weight ratio of HSY-12 molecular sieve to ZSP-3 molecular sieve is 14:1 on a dry basis; both are products of Sinopec Catalyst Qilu Branch; the HSY-12 molecular sieve has a Re2O3 content of 11.6% by weight, a crystallinity of 50.3%, a Na2O content of 0.9% by weight, an Si / Al molar ratio of 2.5, and a crushed particle size d(0.5)=2.6, d(0.9)=6.6); the ZSP-3 molecular sieve has an Fe2O3 content of 1.7% by weight, a P2O5 content of 3.9% by weight, a crystallinity of 78%, a Na2O content of 0.05% by weight, an Si / Al molar ratio of 25, and a crushed particle size d(0.5)=3.9, d(0.9)=7.8); the molecular sieves used in each example and comparative example are the same) were added, and after stirring uniformly, spray drying, washing with water, and drying were carried out to obtain a catalyst, which was recorded as SC1. The obtained SC1 catalyst contains, on a dry basis, 30% by weight of molecular sieve, 42% by weight of kaolin, 25% by weight of SP1 pseudo-boehmite, and 3% by weight of aluminum sol.

[0133] (Example 2) A sodium aluminate solution with a concentration of 45 g Al2O3 / L was reacted by contacting it with carbon dioxide having a volume fraction of 60% (the volume fraction of CO2 was 60% and the remainder was nitrogen), and the end point pH value was controlled to 10.3. The resulting slurry was transferred to an aging kettle and allowed to stand and age at 180 °C and 1.0 MPa for 2.5 hours. Then, stirring was started under the temperature and pressure maintained at 180 °C and 1.0 MPa, the stirring speed was maintained at 450 r / min, and aging was carried out for 1 hour. After aging, the resulting slurry was subjected to solid-liquid separation and continuously washed with deionized water at 95 °C for 30 minutes until the pH of the wet filter cake reached 7.3, and a wet filter cake of pseudo-boehmite with impurities removed was obtained. This wet filter cake was dried at 90 °C for 4 hours and pulverized to obtain pseudo-boehmite powder SP2, and its physical and chemical properties are shown in Table 1.

[0134] Referring to the preparation method of Example 1, according to the conventional preparation method of a catalytic cracking catalyst, HSY-12 molecular sieve, ZSP-3 molecular sieve, kaolin, water, SP2 pseudo-boehmite binder and aluminum sol were slurried, and the slurry was spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst was recorded as SC2. The obtained SC2 catalyst contained 30% by weight of molecular sieves (HSY-12 molecular sieve and ZSP-3 molecular sieve), 42% by weight of kaolin, 25% by weight of SP2 pseudo-boehmite and 3% by weight of aluminum sol on a dry basis.

[0135] (Example 3) A sodium aluminate solution with a concentration of 8 g Al2O3 / L was reacted by contacting it with carbon dioxide having a volume fraction of 35% (the volume fraction of CO2 was 35% and the remainder was nitrogen), and the endpoint pH value was controlled to 9.3. The obtained slurry was transferred to an aging kettle and allowed to stand and age at 120 °C and 0.2 MPa for 4 hours. Then, stirring was started under the condition of maintaining the temperature and pressure at 120 °C and 0.2 MPa, the stirring speed was maintained at 100 r / min, and aging was carried out for 2.5 hours. After aging, the obtained slurry was subjected to solid-liquid separation, and using deionized water at 75 °C, it was continuously washed for 30 minutes until the pH value of the wet filter cake reached 7.1, and a wet filter cake of pseudo-boehmite with impurities removed was obtained. This wet filter cake was dried at 75 °C for 4 hours and pulverized to obtain pseudo-boehmite powder SP3, and its physical and chemical properties are shown in Table 1.

[0136] According to the method of Example 1, using SP3 instead of SP1, catalyst SC3 was prepared.

[0137] (Example 4) A sodium aluminate solution with a concentration of 15 g Al2O3 / L was reacted by contacting it with carbon dioxide having a volume fraction of 50% (the volume fraction of CO2 was 50% and the remainder was nitrogen), and the endpoint pH value was controlled to 9.7. The obtained slurry was transferred to an aging kettle and allowed to stand and age at 150 °C and 0.48 MPa for 5 hours. Then, stirring was started under the condition of maintaining the temperature and pressure at 150 °C and 0.48 MPa, the stirring speed was maintained at 250 r / min, and aging was carried out for 4 hours. After aging, the obtained slurry was subjected to solid-liquid separation, and using deionized water at 80 °C, it was continuously washed for 30 minutes until the pH value of the wet filter cake reached 7.3, and a wet filter cake of pseudo-boehmite with impurities removed was obtained. This wet filter cake was dried at 85 °C for 4 hours and pulverized to obtain pseudo-boehmite powder SP4, and its physical and chemical properties are shown in Table 1.

[0138] According to the method of Example 1, using SP4 instead of SP1, catalyst SC4 was prepared.

[0139] (Example 5) A sodium aluminate solution with a concentration of 55 g Al2O3 / L was reacted by contacting it with carbon dioxide having a volume fraction of 90% (the volume fraction of CO2 was 90% and the remainder was nitrogen), and the reaction was carried out while controlling the end point pH value to 10.0. The obtained slurry was transferred to an aging kettle and allowed to stand and age at 160 °C and 0.62 MPa for 7 hours. Then, stirring was started under the condition of maintaining the temperature and pressure at 160 °C and 0.62 MPa, the stirring speed was maintained at 350 r / min, and aging was carried out for 5 hours. After aging, the obtained slurry was subjected to solid-liquid separation, and using deionized water at 90 °C, it was continuously washed for 30 minutes until the pH value of the wet filter cake reached 7.4, and a wet filter cake of pseudo-boehmite with impurities removed was obtained. This wet filter cake was dried at 95 °C for 4 hours and pulverized to obtain pseudo-boehmite powder SP5, and its physical and chemical properties are shown in Table 1.

[0140] According to the method of Example 1, using SP5 instead of SP1, catalyst SC5 was prepared.

[0141] (Comparative Example 1) A sodium aluminate solution with a concentration of 20 g Al2O3 / L was reacted with carbon dioxide having a volume fraction of 40% to form a gel, and the end point pH value was controlled to 9.5. The obtained slurry was transferred to an aging kettle and allowed to stand and age at 90 °C for 3 hours. After aging, the obtained slurry was subjected to solid-liquid separation, and using deionized water at 78 °C, it was washed for 30 minutes to obtain a product filter cake with impurities removed, dried at 90 °C for 3 hours, and pulverized to obtain pseudo-boehmite powder DP1, and its physical and chemical properties are shown in Table 1.

[0142] Molecular sieve (the same molecular sieve used in Example 1), kaolin, water, DP1 pseudo-boehmite binder, and aluminum sol were slurried according to the usual preparation method of a catalytic cracking catalyst and spray-dried to prepare a microspherical catalyst. The prepared catalytic cracking catalyst was recorded as DC1 (refer to the preparation method of Example 1). The obtained DC1 catalyst contained, on a dry basis, 30% by weight of molecular sieve, 42% by weight of kaolin, 25% by weight of DP1 pseudo-boehmite, and 3% by weight of aluminum sol.

[0143] (Comparative Example 2) A sodium aluminate solution with a concentration of 20 g Al2O3 / L was reacted with carbon dioxide at a volume fraction of 40%, and the pH at the end point was controlled to 9.5. The resulting slurry was transferred to an aging kettle and allowed to stand and age at 135 °C and 0.35 MPa for 3.5 hours. After aging, the resulting slurry was subjected to solid-liquid separation and continuously washed with deionized water at 80 °C for 30 minutes to obtain a wet filtration cake of pseudo-boehmite with impurities removed. This wet filtration cake was dried at 80 °C for 3 hours and pulverized to obtain pseudo-boehmite powder DP2, and its physical and chemical properties are shown in Table 1.

[0144] Molecular sieve, kaolin, water, DP2 pseudo-boehmite binder, and aluminum sol were slurried according to the conventional method for preparing a catalytic cracking catalyst, and this slurry was spray-dried to prepare a microspherical catalyst. The prepared catalytic cracking catalyst was recorded as DC2 (refer to the preparation method of Example 1). The obtained DC2 catalyst contains 30 wt% molecular sieve, 42 wt% kaolin, 25 wt% DP2 pseudo-boehmite, and 3 wt% aluminum sol on a dry basis.

[0145] (Comparative Example 3) Using a high-purity sodium aluminate solution with an Al2O3 content of 45 g / L as a raw material, CO2 with a concentration of 40% was introduced to carry out a gelation reaction. The flow rate per hour was 3.0 m 3 / h, the reaction time was 40 minutes, the residual amount of Al2O3 was 5 g / l, and the final temperature was controlled to 35 °C. After the reaction, the slurry was separated and washed, and the filter cake was washed with high-purity water at 85 °C until the pH value of the filter cake reached 7.0. The filter cake prepared above was added to high-purity water and stirred, and then urea with a concentration of 8 g / L was added thereto. After stirring for 50 minutes, the slurry was transferred to an autoclave apparatus, the autoclave temperature was controlled to 150 °C, the pressure was 0.6 MPa, and it was allowed to stand and age for 3 hours. After aging, it was continuously washed with deionized water at 85 °C for 30 minutes, filtered, and dried at 90 °C. By pulverization, the final product, pseudo-boehmite DP3, was obtained, and its physical and chemical properties are shown in Table 1.

[0146] Molecular sieve, kaolin, water, DP3 pseudo-boehmite binder, and aluminum sol were slurried according to the conventional preparation method of catalytic cracking catalysts, and this slurry was spray-dried to prepare microspherical catalysts. The prepared catalytic cracking catalyst is recorded as DC3 (refer to the preparation method of Example 1). The obtained DC3 catalyst contains 30% by weight of molecular sieve, 42% by weight of kaolin, 25% by weight of DP3 pseudo-boehmite, and 3% by weight of aluminum sol on a dry basis.

[0147] (Comparative Example 4) A reaction was carried out by contacting a sodium aluminate solution with a concentration of 45 g Al2O3 / L with carbon dioxide gas having a volume fraction of 60% (the volume fraction of CO2 is 60% and the rest is nitrogen), and the end point pH value was controlled to 10.3. The obtained slurry was transferred to an aging kettle, and the stirring speed was maintained at 450 r / min at 180 °C and 1.0 MPa, and aging was carried out for 3.5 hours. After aging, the obtained slurry was subjected to solid-liquid separation, and using deionized water at 95 °C, continuous washing was carried out for 30 minutes until the pH value of the wet filter cake reached 7.3, and a wet filter cake of pseudo-boehmite with impurities removed was obtained. This wet filter cake was dried at 90 °C for 4 hours and pulverized to obtain pseudo-boehmite powder DP4, and its physical and chemical properties are shown in Table 1.

[0148] Catalyst DC4 was prepared by referring to the method of Example 1 and using DP4 instead of SP1.

[0149]

Table 1

[0150] As can be seen from Table 1, the pseudo-boehmite provided by the present invention has high crystallinity, large crystal size, and a larger D (130) / D (020), having a larger most probable pore diameter and better peptization performance, and the most probable pores of the fired sample after peptization are still large. Compared with the existing pseudo-boehmite, when the pseudo-boehmite provided by the present invention is used in the preparation of a catalytic cracking catalyst, it can be seen that it has a higher most probable pore diameter and can provide more mesoporous structures.

[0151] (Examples 6 - 10) Examples 6 - 10 show the catalytic cracking reaction performance of the pseudo-boehmite provided by the present invention.

[0152] The SC1 - SC5 catalysts were aged at 800 °C for 17 hours using 100% steam, and then their catalytic cracking performance was evaluated in a small fixed fluidized bed reactor (ACE). The cracked gas and the produced oil were respectively recovered and analyzed by gas chromatography. The catalyst loading was 9 g, the reaction temperature was 500 °C, and the weight hourly space velocity was 16 h -1 ; the properties of the feed oil in the ACE experiment are shown in Table 3, and the evaluation results are shown in Table 4.

[0153] (Comparative Examples 5 - 8) Comparative Examples 5 - 8 show the reaction performance of the catalytic cracking catalysts prepared from the pseudo-boehmite of Comparative Examples 1 - 3.

[0154] The DC1 - DC4 catalysts were aged at 800 °C for 17 hours using 100% steam, and then their catalytic cracking performance was evaluated in a small fixed fluidized bed reactor (ACE). The properties of the feed oil in the ACE experiment are shown in Table 3, and the evaluation results are shown in Table 4.

[0155]

Table 2

[0156] As shown in Table 1, the pseudo-boehmite provided by the present invention has a larger crystal size and a larger D (130) / D (020), having a larger most probable pore diameter, higher crystallinity, and better peptization performance, and the most probable pore diameter of the fired sample after peptization is still large. As shown in Table 2, the catalytic cracking catalyst provided by the present invention has a larger mesopore distribution. In addition to the pore distribution at 3.8 nm, there is also a certain mesopore distribution at higher pore diameters. The catalyst prepared from conventional pseudo-boehmite has a mesopore distribution only at 3.8 nm.

[0157]

Table 3

[0158]

Table 4

[0159] As can be seen from Table 4, the catalytic cracking catalyst provided by the present invention has significantly low coke selectivity, higher gasoline yield, and liquefied gas yield. In particular, when D (130) of pseudo-boehmite having specific properties is 7.8 - 8.2 and D (130) / D (020) is higher than 1.2, significantly high gasoline yield and liquefied gas yield can be achieved.

Claims

1. The crystal size D of pseudo - boehmite （１３０） and D （０２０） The ratio of is D （１３０） / D （０２０） = 1.0 to 1.5, preferably 1.1 to 1.3, characterized in that it is pseudo - boehmite.

2. The crystal size D is measured by powder X - ray diffraction (XRD), The crystal size D is calculated by Scherrer's formula 【Equation 1】 where K = 1.075, λ is the wavelength of the anode radiation Kα1 spectral line, β is the full - width at half - maximum (unit: radian) of a specific diffraction peak of pseudo - boehmite, θ is the Bragg diffraction angle (unit: degree) of the diffraction peak, D represents the crystal size of the sample perpendicular to the (130) crystal plane, （１３０） 【Equation 2】 β １３０ is the full - width at half - maximum of the (130) diffraction peak of the sample (corresponding to 2θ = 38.3°) D （０２０） represents the crystal size of the sample perpendicular to the (020) crystal plane, 【Equation 3】 β ０２０ is the full - width at half - maximum of the (020) diffraction peak of the sample (corresponding to 2θ = 14.1°), characterized in that it is the pseudo - boehmite according to Claim 1.

3. The molecular formula of the pseudo - boehmite is AlOOH·nH ２ O, n = 0.08 to 0.62, The crystal size D of the pseudo - boehmite （１３０） is 10 nm or less, characterized in that it is the pseudo - boehmite according to Claim 1 or 2.

4. The crystal size of the pseudo - boehmite is D （１３０）It is 4 nm to 10 nm, preferably 6.5 nm to 8.2 nm, or 7.8 nm to 8.2 nm, and is characterized in that it is the pseudo-boehmite according to any one of claims 1 to 3.

5. It has a most probable pore diameter exceeding 4.5 nm and not exceeding 12 nm, for example 4.8 nm to 11 nm, or 5 nm to 10 nm, and is characterized in that it is the pseudo-boehmite according to any one of claims 1 to 4.

6. It has a crystallinity of 85% to 110%, for example 88% to 108%, and is characterized in that it is the pseudo-boehmite according to any one of claims 1 to 5.

7. The peptization index of the pseudo-boehmite is 90% to 100%, for example 93% to 99%, and is characterized in that it is the pseudo-boehmite according to any one of claims 1 to 6.

8. The pore volume of the pseudo-boehmite is 0.3 cm ３ / g to 0.58 cm ３ / g, for example 0.31 cm ３ / g to 0.52 cm ３ / g, and is characterized in that it is the pseudo-boehmite according to any one of claims 1 to 7.

9. A method for preparing pseudo-boehmite, comprising the following steps: (1) A step of reacting a sodium aluminate solution with CO ２ to form a first slurry; (2) Aging the first slurry under certain conditions to obtain an aged slurry; The aging under certain conditions includes first static aging and then aging under stirring, and the temperature of the aging is above 100 °C and below 185 °C, step; (3) A step of filtering, washing, and drying the aged slurry.

10. In the step (1), the concentration of the sodium aluminate solution is 5 g / L to 60 g / L in terms of Al ２ O ３ ; and, Sodium aluminate solution and CO ２ The method for preparing pseudo-boehmite according to claim 9, characterized in that the pH value at the end point of the reaction with is 8.5 to 10.

5.

11. In the step (1), the reaction conditions of the sodium aluminate solution and CO ２ are such that the starting temperature of the reaction is 10°C to 35°C, and CO ２ The concentration is 20% to 100% by volume of CO ２ The contained gas (the balance is an inert gas such as nitrogen) is introduced into the sodium aluminate solution to carry out the reaction, and the end temperature of the reaction is preferably 15°C to 55°C. The method for preparing pseudo-boehmite according to claim 9 or 10, characterized by including this.

12. In the step (2), for the slurry, the aging temperature is 120°C to 180°C, the aging pressure is 0.2 MPa to 1 MPa, and the aging time is 2 hours to 12 hours, for example, 2 hours to 10 hours. The method for preparing pseudo-boehmite according to any one of claims 9 to 11, characterized by this.

13. The time of the static aging in the step (2) is 1 hour to 8 hours, for example, 2.5 hours to 7 hours, or 1 hour to 4 hours, for example, 2 hours to 3 hours, and the time of the aging under stirring is 1 hour to 6 hours. The method for preparing pseudo-boehmite according to any one of claims 9 to 12, characterized by this.

14. The aging temperature is 135°C to 180°C, and the aging is preferably aging at a constant temperature. The method for preparing pseudo-boehmite according to any one of claims 9 to 13, characterized by this.

15. The stirring speed of the aging under stirring is 50 r / min to 450 r / min, 100 r / min to 400 r / min. The method for preparing pseudo-boehmite according to any one of claims 9 to 14, characterized by this.

16. In the step (2), The conditions for the static aging include that the temperature is 120°C to 180°C, preferably 135°C to 180°C, the pressure is 0.2 MPa to 1 MPa, the time is 1 hour to 8 hours, for example, 2.5 hours to 7 hours, and the stirring speed is 100 r / min to 450 r / min; The conditions for the aging under stirring include that the temperature is 120°C to 180°C, preferably 135°C to 180°C, the pressure is 0.2 MPa to 1 MPa, the time is 1 hour to 6 hours, for example 1 hour to 5 hours; Preferably, the ratio of the time of static aging to the time of aging under stirring is 1 to 5:1, preferably 1.25 to 3:

1. The method for preparing pseudo-boehmite according to any one of claims 9 to 15 is characterized in that.

17. The washing conditions in the step (3) are washing with deionized water at 70°C to 100°C until the pH value of the wet filter cake reaches 7 to 7.5; and the drying in the step (3) is carried out at a drying temperature of 70°C to 98°C. The method for preparing pseudo-boehmite according to any one of claims 9 to 16 is characterized in that.

18. As a catalyst, carrier and binder in the petroleum industry; as a carrier coating for automotive exhaust treatment catalysts in the automotive industry; as an additive for flame-retardant materials in the fire protection field; as an ink absorption coating agent for high-grade inkjet printing paper in the paper industry; as a gas purification adsorbent, drinking water defluorination agent, industrial wastewater decolorization and deodorization agent in the environmental protection industry; as a coating additive in the construction industry; and as a reinforcing material in ceramic composite materials. The use of pseudo-boehmite according to any one of claims 1 to 8.

19. It contains 10% to 50% by weight of Y-type molecular sieve on a dry basis, 0 to 40% by weight of other molecular sieves on a dry basis, 10% to 40% by weight of pseudo-boehmite according to any one of claims 1 to 8 calculated as alumina, 3% to 20% by weight of a binder calculated as an oxide, and 10% to 80% by weight of clay on a dry basis; Preferably, the other molecular sieve is one or more of MFI structure zeolite, beta zeolite, and non-zeolite molecular sieve; more preferably, the other molecular sieve is one or more of HZSM-5, ZRP, and ZSP; and / or, Preferably, the Y-type molecular sieve is one or more of REY, REHY, DASY, SOY, PSRY, HSY, and HRY. Cracking catalyst.

20. A method for preparing the cracking catalyst according to claim 19, comprising the following steps: A step of preparing the pseudo-boehmite according to any one of claims 1 to 8; A step of forming a slurry containing the pseudo-boehmite, Y-type molecular sieve, optionally another molecular sieve, binder, viscosity, and water, and A step of spray drying.

21. A method for preparing the cracking catalyst according to claim 20, characterized by comprising the following steps: A step of slurrying the pseudo-boehmite according to claims 1 to 8 with water to form a pseudo-boehmite slurry, wherein the solid content is preferably 5% by weight to 25% by weight; A step of adding hydrochloric acid, wherein the mass ratio of HCl to the pseudo-boehmite calculated as alumina is 0.037 to 0.104, and the concentration of hydrochloric acid can be 10% by weight to 37% by weight; Then, mixing it with a slurry containing Y-type molecular sieve, optionally another molecular sieve, binder, clay, and water to obtain a colloidal slurry, wherein the solid content of the slurry is preferably 20% by weight to 40%; A step of spray drying; and Optionally, a step of washing and drying.

22. A catalytic cracking method comprising a step of bringing a heavy oil into contact with and reacting it with a catalytic cracking catalyst under FCC conditions, wherein the catalytic cracking catalyst is the catalytic cracking catalyst according to claim 19, or a catalytic cracking catalyst obtained by the method for preparing a catalytic cracking catalyst according to claim 20 or 21; For example, the FCC conditions include that the reaction temperature is 480°C to 530°C, the reaction time is 1 to 10 seconds, and the weight ratio of the catalyst to the oil is 3 to 20:

1. A catalytic cracking method characterized by this.

Images