CN109721074B

CN109721074B - Phosphorus-containing molecular sieve, and preparation method and application thereof

Info

Publication number: CN109721074B
Application number: CN201711046511.7A
Authority: CN
Inventors: 毛以朝; 李明丰; 张润强; 赵阳; 赵广乐
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-10-31
Filing date: 2017-10-31
Publication date: 2021-03-12
Anticipated expiration: 2037-10-31
Also published as: CN109721074A

Abstract

The invention relates to a phosphorus-containing molecular sieve and a preparation method and application thereof, wherein the phosphorus content of the molecular sieve is 0.3-5 wt%, the pore volume is 0.2-0.95 ml/g, the ratio of pyridine infrared B acid to L acid is 2-15, and Al of the molecular sieve is calculated by oxide²⁷In NMR structural spectrum, I_60ppm/I_‑1ppmIs 5 to 15, I_‑1ppm/I_±6ppm0.4 to 2. The molecular sieve has higher ratio of B acid amount to L acid amount, and shows higher hydrocracking activity and ring opening selectivity when being used for preparing a hydrocracking catalyst.

Description

Phosphorus-containing molecular sieve, and preparation method and application thereof

Technical Field

The present disclosure relates to a phosphorus-containing molecular sieve, a preparation method and applications thereof.

Background

The industrial hydrocracking feed comprises 350-540 ℃ fractions such as VGO and the like, and contains a large amount of polycyclic aromatic hydrocarbons and cycloparaffins, and researches show that in a hydrocracking high-conversion-rate area, the content of the aromatic hydrocarbons in the heavy fraction is reduced, and the content of the cycloparaffins is high, so that the ring opening performance becomes an effective means for improving the quality of tail oil and increasing the smoke point of aviation kerosene. However, since the beta bond in the cycloalkane is in the vertical direction of the empty p orbital of the cycloalkane carbonium ion, so that the two are not easily formed into a coplanar conformation, this makes the cycloalkane ring-opening require stronger acidity. The molecular sieve has high acidity and is widely applied to hydrocracking reaction. However, the common HY molecular sieve has an unstable structure, framework dealumination is easy to occur in the catalyst preparation and use processes, non-framework aluminum generated in the molecular sieve preparation process is generally weak in acid, a B acid center is shielded, and the catalyst performance is reduced. The molecular sieve structure can be stabilized by performing the ultra-stabilization treatment in the modes of hydrothermal treatment, introduction of a second component and the like. The second component introduced therein generally comprises an olefinic component and a phosphorus component. As phosphorus and non-framework aluminum removed from the molecular sieve form a phosphorus-aluminum oxide complex with larger molecular weight in the roasting process, the complex has higher thermal stability and is beneficial to preventing framework dealumination, so that the complex can replace the function of rare earth components to a certain extent.

Patent CN1279130A discloses a process for preparing a phosphorus-containing Y-type molecular sieve, which comprises mixing a phosphorus-containing Y-type molecular sieve containing 0.5-5 wt% (as P)₂O₅Calculated) phosphorus, Na₂P-NH with O content of 0.5-6 wt% and unit cell constant of 2.460-2.475 nm₄Carrying out hydrothermal roasting on the NaY molecular sieve for 0.5-4 hours at 450-700 ℃ in a roasting furnace under the atmosphere of 100% steam; carrying out liquid-phase aluminum extraction and silicon supplement reaction on the roasted product; then filtered and washed. The obtained phosphorus-containing ultrastable Y-type molecular sieve has good product selectivity, hydrothermal stability and good vanadium poisoning resistance, and when the cracking catalyst containing the molecular sieve is used for hydrocarbon cracking reaction, the yield of light oil is high, the yield of coke is low, the conversion capacity of heavy oil is high, and the olefin content in gasoline is low.

Patent ZL200410071122.6 discloses a phosphorus-containing molecular sieve containing 85-99.9 wt% of molecular sieve and P₂O₅0.1 to 15% by weight of phosphorus, based on the weight of the molecular sieve³¹In PMAS-NMR spectrum, the percentage of peak area of peak with chemical shift of 0 + -1.0 ppm in total peak area is less than 1%. The preparation method of the molecular sieve comprises the step of introducing the molecular sieve into the molecular sieveAdding phosphorus, and washing the molecular sieve with an aqueous solution containing acid, wherein the acid is selected from one or more of water-soluble organic acid and inorganic acid, the acid content is 0.0001-10.0 mol/L, and the washing temperature is room temperature-95 ℃. The invention is characterized in that after the introduction of phosphorus, the method comprises a step of washing the molecular sieve by an acid solution, and the hydrocracking catalyst prepared by the phosphorus-containing molecular sieve has higher hydrocracking activity while maintaining high selectivity.

The prior art generally post-treats phosphorus-containing molecular sieves to further improve the stability and acidity of the molecular sieves. These post-treatment methods typically include hydrothermal treatment and acid treatment. In general, the introduction mode of water in the hydrothermal treatment process comprises two modes, namely introducing water vapor in the roasting process and releasing the water by the self-heating roasting of materials. In the two modes, as the water vapor pressure is increased sharply along with the rise of the temperature, in order to enable the existing equipment to bear the requirement of the reaction pressure, an open system is usually adopted, so that the powder is continuously taken out of the system along with the water vapor in the hydrothermal process, the reaction system is in unsteady operation, the product quality is not high, and the obtained molecular sieve has certain ring-opening capacity but still cannot meet the actual requirement.

Disclosure of Invention

The purpose of the present disclosure is to provide a phosphorus-containing molecular sieve, and a preparation method and an application thereof, wherein the molecular sieve has higher ratio of B acid to L acid and higher reaction activity.

To achieve the above object, a first aspect of the present disclosure: the phosphorus-containing molecular sieve comprises 0.3-5 wt% of phosphorus, 0.2-0.95 ml/g of pore volume, 2-15 of pyridine infrared B acid and L acid, and calculated by oxide, wherein Al in the molecular sieve²⁷In NMR structural spectrum, I_60ppm/I_-1ppmIs 5 to 15, I_-1ppm/I_±6ppm0.4 to 2.

In a second aspect of the present disclosure: there is provided a process for preparing the phosphorus-containing molecular sieve of claim 1, the process comprising:

a. placing the phosphorus-containing molecular sieve raw material in a hydrothermal kettle, and carrying out hydrothermal treatment for 0.5-10h at the temperature of 350-700 ℃ in the presence of water vapor to obtain a molecular sieve material after the hydrothermal treatment; the outlet of the hydrothermal kettle is connected with a filter, an open pipeline is arranged on the filter, inert particle fillers are arranged in the filter, and the pressure of hydrothermal treatment is 0.1-2 MPa; calculated by oxide and based on the dry weight of the phosphorus-containing molecular sieve raw material, the phosphorus content of the phosphorus-containing molecular sieve raw material is 0.1-15 wt%, and the sodium content is 0.5-4.5 wt%;

b. b, adding water into the molecular sieve material subjected to the hydrothermal treatment obtained in the step a for pulping to obtain molecular sieve slurry, heating the molecular sieve slurry to 40-95 ℃, keeping the temperature, and continuously adding an acid solution into the molecular sieve slurry, wherein the ratio of the weight of acid in the acid solution to the dry weight of the phosphorus-containing molecular sieve raw material is (0.01-0.6): 1, after the acid is added, reacting for 0.5-20h at constant temperature, and then collecting a solid product.

Optionally, in the step a, the inert particles are spherical, and the diameter of the inert particles is 1-100 mm.

Optionally, in step a, the diameter of the inert particles is 3-30 mm.

Optionally, in step a, the material of the inert particles is at least one selected from the group consisting of silicon oxide, aluminum oxide and zirconium oxide.

Optionally, in the step a, the phosphorus-containing molecular sieve is a phosphorus-containing Y-type molecular sieve, the unit cell constant of the phosphorus-containing Y-type molecular sieve is 2.425-2.47 nm, and the specific surface area is 250-750 m²The pore volume is 0.2 to 0.95 ml/g.

Optionally, in the step a, the water content of the phosphorus-containing molecular sieve raw material is 10-40 wt%;

the phosphorus-containing molecular sieve raw material is granular, the content of the phosphorus-containing molecular sieve raw material with the granularity range of 1 mm-500 mm is 10-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material, and the granularity is calculated by the diameter of a circumscribed circle of the granules.

Optionally, the content of the phosphorus-containing molecular sieve raw material with the particle size range of 1 mm-500 mm is 30-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material.

Optionally, the content of the phosphorus-containing molecular sieve raw material with the particle size range of 5 mm-100 mm is 30-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material.

Optionally, in step b, the ratio of the weight of water in the molecular sieve slurry obtained after pulping to the dry weight of the phosphorus-containing molecular sieve raw material is (14-5): 1.

optionally, in the step b, the acid concentration of the acid solution is 0.01-15.0 mol/L, and the acid is at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid and acetic acid.

Optionally, in step b, the acid solution is added in a manner that: based on 1L of the molecular sieve slurry, taking H as the reference⁺The acid solution is added to the molecular sieve slurry at a rate of 0.05 to 10 moles/hour.

Optionally, the method further comprises: in the step b, adding ammonium salt into the molecular sieve slurry in the process of adding the acid solution, wherein the ammonium salt is at least one selected from ammonium nitrate, ammonium chloride and ammonium sulfate, and the weight ratio of the ammonium salt to the dry basis weight of the phosphorus-containing molecular sieve raw material is (0.1-2.0): 1.

optionally, the method further comprises: collecting the solid product, then washing with water and drying to obtain a phosphorus-containing molecular sieve; the drying conditions are as follows: the temperature is 50-350 ℃, and preferably 70-200 ℃; the time is 1-24 h, preferably 2-6 h.

A third aspect of the disclosure: there is provided the use of a phosphorus-containing molecular sieve according to the first aspect of the present disclosure in a hydrocracking reaction of a hydrocarbon feedstock.

Optionally, the hydrocarbon feedstock is at least one selected from the group consisting of straight run gas oil, vacuum gas oil, demetallized oil, atmospheric residue, deasphalted vacuum residue, coker distillate, catalytically cracked distillate, shale oil, tar sand oil, and coal liquefaction oil;

the conditions of the hydrocracking reaction are as follows: the reaction temperature is 200-650 ℃, preferably 300-510 ℃; the reaction pressure is 3-24 MPa, preferably 4-15 MPa; the liquid hourly space velocity is 0.1-10 hours^-1Preferably 0.2 to 5 hours^-1(ii) a The volume ratio of hydrogen to oil is 100-1000。

Through the technical scheme, the phosphorus-containing molecular sieve raw material is subjected to special hydrothermal treatment and acid washing treatment to prepare the molecular sieve with excellent performance, and the ratio of B acid to L acid is further improved. Particularly, the filter is additionally arranged at the outlet of the closed kettle for hydrothermal treatment, and inert particles are filled in the filter, so that the filtering effect can be indirectly provided, the material loss is reduced, and the operation stability is improved. The phosphorus-containing molecular sieves of the present disclosure exhibit higher hydrocracking activity and ring opening selectivity when used to prepare hydrocracking catalysts relative to conventional processes.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is Al of molecular sieves prepared in preparation examples and preparation comparative examples²⁷-NMR structural spectrum.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The first aspect of the disclosure: the phosphorus-containing molecular sieve is provided, wherein the phosphorus content of the molecular sieve is 0.3-5 wt% calculated by oxide, the pore volume is 0.2-0.95 ml/g, and the ratio of pyridine infrared B acid to pyridine infrared L acid is 2-15.

The molecular sieve provided by the present disclosure has a higher ratio of the amount of the B acid to the amount of the L acid. Particularly, the molecular sieve provided by the disclosure not only retains a high ratio of framework aluminum to non-framework aluminum, but also retains certain non-framework aluminum at a position of-4 to-6 ppm or at a position of 3 to 7 ppm. In particular, Al of the molecular sieve²⁷-NMR structural spectrum at 60. + -.1 ppm and-1. + -.1 ppm of framework and non-framework aluminiumPeak height ratio I_60ppm/I_-1ppm5 to 15; and the chemical shift position of 0ppm of non-framework aluminum has two obvious characteristic peaks: -1 + -1 ppm, and-5.5 + -2 ppm or 3-7 ppm, the peak height ratio of the two being I_-1ppm/I_±6ppm0.4 to 2, preferably 0.8 to 2, wherein I_±6ppmTaking the larger value of peak height of-5.5 +/-2 ppm and 3-7 ppm.

In a second aspect of the present disclosure: there is provided a process for preparing a phosphorus-containing molecular sieve according to the first aspect of the present disclosure, the process comprising:

According to the method, the filter is additionally arranged at the outlet of the hydrothermal kettle, and the inert particles are filled in the filter, so that the filtering effect can be indirectly provided, the molecular sieve material in the reaction process cannot be directly taken out of the system, but needs to be intercepted by the filter, the molecular sieve material loss can be greatly reduced, and the operation stability is improved. Meanwhile, an opening pipeline arranged on the filter can ensure that the pressure in the hydrothermal kettle is maintained at a required constant pressure, and operation failure caused by overhigh pressure is avoided.

According to the present disclosure, in the step a, the inert particles in the filter may be uniformly spherical, and the diameter of the inert particles may be 1 to 100mm, preferably 3 to 30 mm. The inert particles are made of a material resistant to high temperature and corrosion, and may be made of at least one material selected from the group consisting of silica, alumina, and zirconia, for example. The present disclosure does not particularly limit the shape and size of the filter as long as the object of the present disclosure can be achieved. The open line may be conventional in the art, and may be, for example, an open line having a diameter of 10 to 300 mm.

According to the present disclosure, in step a, the phosphorus-containing molecular sieve raw material refers to a phosphorus-containing molecular sieve. The method adopts the phosphorus-containing molecular sieve as a raw material, and phosphorus aluminum species outside the molecular sieve framework can improve the framework stability of the molecular sieve, so that the performance of the molecular sieve is further improved. The structure of the phosphorus-containing molecular sieve raw material can be an octahedral zeolite molecular sieve structure, preferably a phosphorus-containing Y-type molecular sieve, the unit cell constant of the phosphorus-containing molecular sieve raw material can be 2.425-2.47 nm, and the specific surface area of the phosphorus-containing molecular sieve raw material can be 250-750 m²The pore volume may be 0.2 to 0.95 ml/g. Further, the specific selection of the Y-type molecular sieve may be widely varied as long as the phosphorus-containing molecular sieve raw material satisfies the above conditions, and for example, the Y-type molecular sieve may be selected from NaY, HNaY (hydrogen Y-type molecular sieve), REY (rare earth Y-type molecular sieve), USY (ultra stable Y-type molecular sieve), and the like. The cation position of the phosphorus-containing Y-type molecular sieve can be occupied by one or more of sodium ions, ammonium ions and hydrogen ions; alternatively, the sodium, ammonium, and hydrogen ions may be replaced by other ions, either before or after the molecular sieve is introduced with phosphorus, by conventional ion exchange. The phosphorus-containing molecular sieve raw material can be a commercial product, and can also be prepared by any prior art, for example, a method for preparing USY disclosed in a patent ZL00123139.1, or a method for preparing PUSY disclosed in a patent ZL200410071122.6 and the like can be adopted, and the details of the disclosure are not repeated.

According to the disclosure, in the step a, the water content of the phosphorus-containing molecular sieve raw material is preferably 10 to 40 wt%. The phosphorus-containing molecular sieve raw material with the water content can be obtained by adding water into the molecular sieve, pulping, filtering and drying. The phosphorus-containing molecular sieve raw material is preferably granular, and the content of the phosphorus-containing molecular sieve raw material with the granularity range of 1 mm-500 mm can be 10-100 wt%, preferably 30-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material. Further, the content of the phosphorus-containing molecular sieve raw material with the granularity range of 5 mm-100 mm is 30-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material. Wherein the particle size is in terms of the diameter of the circumscribed circle of particles. The adoption of the phosphorus-containing molecular sieve raw material with the granularity range for hydrothermal treatment can obviously improve the mass transfer effect of the hydrothermal treatment, reduce the material loss and improve the stability of operation. The particle size control method of the molecular sieve raw material can be conventional in the field, such as a sieving method, an extrusion strip method, a rolling ball method and the like.

According to the present disclosure, the meaning of the water-adding beating in step b is well known to those skilled in the art, and the ratio of the weight of water in the molecular sieve slurry obtained after beating to the dry weight of the phosphorus-containing molecular sieve raw material can be (14-5): 1.

according to the present disclosure, in the step b, the molecular sieve slurry is preferably heated to 50-85 ℃, and then the temperature is maintained and the acid solution is continuously added to the molecular sieve slurry until the weight of the acid in the added acid solution reaches a set amount. The acid solution may be added in a manner of: based on 1L of the molecular sieve slurry, taking H as the reference⁺The acid solution is added to the molecular sieve slurry at a rate of 0.05 to 10 moles/hour. The continuous acid adding mode is adopted, acid adding and acid washing reaction are carried out simultaneously, and the acid adding speed is low, so that the dealumination process is more moderate, and the improvement of the performance of the molecular sieve is facilitated.

According to the present disclosure, the acid solution may be continuously added to the molecular sieve slurry at one time, that is, the whole acid solution is continuously added according to a specific acid adding speed, and then the reaction is performed at a constant temperature. In particular, the acid solution may also be added in multiple portions in order to increase the utilization of the material and reduce the waste output. For example, the acid solution can be added to the molecular sieve slurry at a specific acid addition rate of 2-10 times, and after each acid addition, the reaction can be carried out at constant temperature for a period of time to continue the next acid addition until the set amount of the acid solution is added. When the acid solution is added in multiple portions, the ratio of the weight of acid in the acid solution to the dry weight of the phosphorus-containing molecular sieve starting material is preferably (0.01-0.6): 1. the acid concentration of the acid solution can be 0.01-15.0 mol/L, and the pH value can be 0.01-3. The acid may be a conventional inorganic acid and/or organic or acid, and for example, may be at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid and acetic acid.

According to the present disclosure, the method may further comprise: in step b, adding an ammonium salt into the molecular sieve slurry during the adding of the acid solution, wherein the ammonium salt can be at least one selected from ammonium nitrate, ammonium chloride and ammonium sulfate, and the weight ratio of the ammonium salt to the dry weight of the phosphorus-containing molecular sieve raw material can be (0.1-2.0): 1. the ammonium salt may be added to the molecular sieve slurry independently of the acid solution, or an aqueous solution containing the ammonium salt and the acid may be prepared in a desired amount and added to the molecular sieve slurry.

According to the present disclosure, the method may further comprise: and collecting the solid product, and then washing and drying to obtain the phosphorus-containing molecular sieve. The washing and drying are conventional steps for preparing the molecular sieve, and the disclosure is not particularly limited. For example, the drying may be performed by using an oven, a mesh belt, a converter, or the like, and the drying conditions may be: the temperature is 50-350 ℃, and preferably 70-200 ℃; the time is 1-24 h, preferably 2-6 h.

The phosphorus-containing molecular sieve raw material is subjected to special hydrothermal treatment and acid washing treatment, so that the molecular sieve with excellent performance can be prepared, and higher hydrocracking activity and ring opening selectivity can be shown when the phosphorus-containing molecular sieve raw material is used for preparing a hydrocracking catalyst.

The molecular sieve provided by the present disclosure can be used as various acid catalytic catalysts in catalytic cracking, hydroisomerization, alkylation, hydrocracking and other reactions, and is particularly suitable for hydrocracking hydrocarbon raw materials to produce hydrocarbon fractions with lower boiling points and lower molecular weights. Accordingly, the third aspect of the present disclosure: there is provided the use of a phosphorus-containing molecular sieve according to the first aspect of the present disclosure in a hydrocracking reaction of a hydrocarbon feedstock.

The hydrocarbon feedstock may be various heavy mineral oils or synthetic oils or their mixed distillates, such as straight run gas oil (straight run gas oil), vacuum gas oil (vacuum gas oil), demetalized oils (demetalized oils), atmospheric residues (atmospheric residues), deasphalted vacuum residues (deasphalted vacuum residues), coker distillates (coker distillates), catalytic cracker distillates (cat distillates), shale oils (shell oils), tar sand oils (tar sand oils), coal liquefied oils (coal liquids), etc. In particular, the catalyst provided by the present disclosure is particularly suitable for hydrocracking of heavy and poor distillate to produce a hydrocracking process of middle distillate with distillation range of 149-371 ℃, especially with distillation range of 180-370 ℃.

The hydrocracking process can be one or more of conventional hydrocracking processes such as a fixed bed, an ebullated bed, a slurry bed, a suspended bed and the like.

The catalyst provided by the present disclosure can be used under conventional hydrocracking process conditions when used for distillate oil hydrocracking, for example, the hydrocracking reaction conditions are as follows: the reaction temperature is 200-.

The present disclosure is further illustrated by the following examples, but is not limited thereto.

The pore volume and the specific surface area of the molecular sieve are measured by a static low-temperature adsorption capacity method (by adopting a national standard GB/T5816-1995 method) by adopting an ASAP 2400 model automatic adsorption instrument of American micromeritics instruments, and the specific method comprises the following steps: vacuumizing and degassing at 250 deg.C and 1.33Pa for 4 hr, contacting with nitrogen as adsorbate at-196 deg.C, and statically reaching adsorption balance; and calculating the nitrogen adsorption amount of the adsorbent according to the difference between the nitrogen gas inflow and the nitrogen gas remaining in the gas phase after adsorption, calculating the pore size distribution by using a BJH (British Ribose) formula, and calculating the specific surface area and the pore volume by using a BET (BET) formula.

The unit cell constant is determined by an X-ray diffractometer model D5005 of Siemens Germany, and is in accordance with the method of industry standard SH/T0339-92. The experimental conditions are as follows: cu target, Ka radiation, solid detector, tube voltage 40kV, tube current 40mA, step scanning, step width of 0.02 degrees, prefabrication time of 2s and scanning range of 5-70 degrees.

The phosphorus content and the sodium content of the molecular sieve are measured by a 3271E type X-ray fluorescence spectrometer of Japan science and Motor industry Co., Ltd, and the measuring method comprises the following steps: tabletting and forming a powder sample, carrying out rhodium target, detecting the spectral line intensity of each element by a scintillation counter and a proportional counter under the laser voltage of 50kV and the laser current of 50mA, and carrying out quantitative and semi-quantitative analysis on the element content by an external standard method.

The ratio of the B acid amount to the L acid amount of the molecular sieve is measured by a Bio-Rad IFS-3000 type infrared spectrometer. The specific method comprises the following steps: the molecular sieve sample is ground and pressed into 10mg/cm²The self-supporting sheet is placed in an in-situ cell of an infrared spectrometer at 350 ℃ and 10 DEG C^-3Surface purification treatment is carried out for 2 hours under Pa vacuum degree, pyridine saturated steam is introduced after the surface purification treatment is carried out to the room temperature, after adsorption equilibrium is carried out for 15 minutes, vacuum desorption is carried out for 30 minutes at 350 ℃, and the adsorption and determination of pyridine vibration spectrum are measured after the surface purification treatment is carried out to the room temperature. The scanning range is 1400cm^-1-1700cm^-1At 1540 + -5 cm^-1The ratio of the infrared absorption of the band to the weight and area of the sample piece defines the amount of B acid [ infrared absorption per unit area, per unit mass of the sample, expressed as: AB (cm)²·g)^-1]. At 1450 + -5 cm^-1The ratio of the infrared absorption value of the band to the weight and area of the sample piece defines the L acid amount [ infrared absorption value per unit area, unit mass of the sample, expressed as: AL (cm)²·g)^-1]The value of AB/AL is defined as the ratio of the amount of B acid to the amount of L acid of the zeolite molecular sieve.

The molecular sieve adopts a Varian UNITYINOVA300M nuclear magnetic resonance instrument to perform sample analysis, wherein the resonance frequency of Al MAS is 78.162MHzs, the rotor speed is 3000Hz, the repetition delay time is 0.5s, the sampling time is 0.020s, the pulse width is 1.6 mus, the spectrum width is 54.7kHz, the data is collected at 2000 points, the cumulative frequency is 800 times, and the test temperature is room temperature.

Yield (%) of the molecular sieve is dry basis weight of the molecular sieve obtained by preparation/dry basis weight of the hydrothermal-treated molecular sieve raw material × 100%.

Preparative examples 1-3 are provided to illustrate methods of preparing phosphorus-containing molecular sieves provided by the present disclosure.

Preparation of example 1

Taking NaY molecular sieve (product of China petrochemical catalyst Chang Ling Branch, product name NaY, unit cell constant of 2.468nm, specific surface area of 680m²Per g, pore volume of 0.30ml/g, Na₂O content 13.0 wt%, Al₂O₃22 wt.%) was added 2.0mol/L of (NH)₄)₂HPO₄Pulping the aqueous solution, filtering, repeating the above process for three times, drying at 100 deg.C for 1h to obtain phosphorus-containing molecular sieve raw material with unit cell constant of 24.48nm and specific surface area of 590m²Per g, pore volume of 0.37ml/g, P₂O₅The content was 4.8% by weight, Na₂The O content was 3.5% by weight.

100Kg of the phosphorus-containing molecular sieve raw material is placed into a hydrothermal kettle, a filter is connected with an outlet of the hydrothermal kettle, an open pipeline with the pipe diameter of 100mm is arranged on the filter, silica particle fillers with the diameter of 1-60mm are filled in the filter, 100% of steam is introduced into the hydrothermal kettle, the temperature is raised to 580 ℃, the pressure in a device is controlled to be 0.8MPa, and the molecular sieve material after hydrothermal treatment is taken out after constant hydrothermal treatment is carried out for 8 hours.

According to the weight ratio of 0.2: 0.4: 1 preparing 100ml of hydrochloric acid-ammonium chloride aqueous solution, wherein the concentration of hydrochloric acid in the aqueous solution is 0.05mol/L, and the concentration of ammonium chloride in the aqueous solution is 0.07 mol/L.

Taking 50g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain molecular sieve slurry, and heating the molecular sieve slurry to 80 ℃. Based on 1L of molecular sieve slurry and H⁺And adding the prepared hydrochloric acid-ammonium chloride aqueous solution into the molecular sieve slurry at a constant speed for three times at a speed of 2mol/h, reacting for 4 hours at a constant temperature after each time of adding acid, filtering, and taking a filter cake to continue to add acid for the next time in the same manner. The last time of acid addition is finished andafter 4h of reaction, collecting the solid product, drying at 180 ℃ for 3h to obtain the phosphorus-containing molecular sieve Y-1, Al of which²⁷The NMR structural spectrum is shown in FIG. 1, and the properties are shown in Table 1.

Preparation of example 2

Taking PSRY molecular sieve (product name PSRY of China petrochemical catalyst Changling Brand, Inc.), wherein the unit cell constant is 2.456nm, and the specific surface area is 620m²Per g, pore volume of 0.39ml/g, Na₂O content 2.2 wt.%, P₂O₅Content of 1.5 wt.%, Al₂O₃Content of 18 wt%) of the phosphorus-containing molecular sieve, adding deionized water, pulping, wherein the total amount of water is 1000ml, filtering, and drying at 70 ℃ for 2h to obtain the phosphorus-containing molecular sieve raw material with the water content of 35 wt%.

Crushing the phosphorus-containing molecular sieve raw material, sieving to 5-20 meshes (wherein 1-500 mm particles account for 70 wt% of the total weight of the phosphorus-containing molecular sieve raw material), putting 100Kg of the phosphorus-containing molecular sieve raw material into a hydrothermal kettle, connecting a filter to an outlet of the hydrothermal kettle, arranging an open pipeline with the pipe diameter of 100 on the filter, filling silicon oxide particle fillers with the diameter of 1-60mm into the filter, introducing 100% of steam into the hydrothermal kettle, heating to 580 ℃, controlling the pressure in a device to be 0.4MPa, carrying out hydrothermal treatment for 2 hours constantly, and taking out the molecular sieve material after the hydrothermal treatment.

According to the weight ratio of 0.02: 1 preparing 250ml of sulfuric acid aqueous solution, wherein the concentration of sulfuric acid in the aqueous solution is 0.2 mol/L.

Taking 50g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain molecular sieve slurry, and heating to 80 ℃. Based on 1L of molecular sieve slurry and H⁺Adding the prepared sulfuric acid aqueous solution into the molecular sieve slurry at a constant speed for three times at a speed of 0.5mol/h, reacting for 2 hours at a constant temperature after each time of acid addition, filtering, and taking a filter cake to continue to add acid for the next time in the same manner. After the last time of acid addition and reaction for 2 hours, collecting the solid product, and drying at 100 ℃ for 8 hours to obtain the phosphorus-containing molecular sieve Y-2, Al of which²⁷The NMR structural spectrum is shown in FIG. 1, and the properties are shown in Table 1.

Preparation of example 3

A phosphorus-containing molecular sieve was prepared according to the method of preparation example 2, except that the phosphorus-containing molecular sieve raw material was crushed, sieved to 5 to 20 mesh (wherein 5mm to 100mm particles account for 70 wt% of the total weight of the phosphorus-containing molecular sieve raw material), and then subjected to hydrothermal treatment and subsequent operations according to the method of preparation example 2, to obtain a phosphorus-containing molecular sieve Y-3, properties of which are shown in table 1.

Preparation of example 4

A phosphorus-containing molecular sieve was prepared according to the method of preparation example 2, except that the filter was packed with silica particle packing having a diameter of 3 to 30mm to obtain molecular sieve Y-4, properties of which are shown in Table 1.

Preparation of comparative examples 1-4 to illustrate a different method of preparing a phosphorus-containing molecular sieve from the present disclosure, the hydrothermal kettle employed in comparative examples 1-4 was not connected at its outlet to a filter.

Preparation of comparative example 1

The phosphorus-containing molecular sieve of this comparative preparation example is the same PSRY molecular sieve as in preparation example 2, and the preparation method thereof can refer to the preparation method of a phosphorus-containing zeolite disclosed in CN1088407C, which comprises directly mixing a phosphorus-containing compound with a raw material zeolite in a weight ratio of 0.1 to 40, heating at 50 to 550 ℃ for at least 0.1 hour under a closed condition, washing the obtained product with deionized water until no acid radical ion exists, and recovering the phosphorus-containing zeolite. It was designated as RY-1, its Al²⁷The NMR structural spectrum is shown in FIG. 1, and the properties are shown in Table 1.

Preparation of comparative example 2

Taking phosphorus-free HY molecular sieve (product name HY, unit cell constant 2.465nm, specific surface area 580m, produced by Zhongshiedian catalyst Chang Ling division Co., Ltd.)²Per g, pore volume of 0.33ml/g, Na₂0.3 wt.% of O, Al₂O₃Content of 22 wt%) was put into a hydrothermal treatment apparatus, 100% steam was introduced, the temperature was raised to 450 ℃, the pressure in the apparatus was controlled at 0.8MPa, and the molecular sieve material after hydrothermal treatment was taken out after constant hydrothermal treatment for 8 hours.

According to the weight ratio of 0.08 of hydrochloric acid, ammonium chloride and phosphorus-containing molecular sieve raw materials: 1.5: 1 preparing 50ml of hydrochloric acid-ammonium chloride aqueous solution, wherein the concentration of hydrochloric acid in the aqueous solution is 0.1mol/L, and the concentration of ammonium chloride in the aqueous solution is 0.14 mol/L.

Taking 50g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain molecular sieve slurry, and heating the molecular sieve slurry to 80 ℃. Based on 1L of molecular sieve slurry and H⁺And adding the prepared hydrochloric acid-ammonium chloride aqueous solution into the molecular sieve slurry at a constant speed for three times at a speed of 2mol/h, reacting for 4 hours at a constant temperature after each time of adding acid, filtering, and taking a filter cake to continue to add acid for the next time in the same manner. After the last time of acid addition and reaction for 4 hours, collecting the solid product, and drying at 180 ℃ for 3 hours to obtain the phosphorus-containing molecular sieve RY-2 and Al thereof²⁷The NMR structural spectrum is shown in FIG. 1, and the properties are shown in Table 1.

Preparation of comparative example 3

300g of PSRY molecular sieve (same as preparation example 2) was taken, and NH at a concentration of 0.5mol/L was added₄600ml of Cl aqueous solution is pulped by deionized water, the total amount of water is 1000ml, the temperature is heated to 90 ℃, and ammonium exchange is carried out for 3 h. Then filtered, washed twice with deionized water and the filter cake heated at 600 ℃ for 4h at atmospheric pressure.

According to the weight ratio of 0.5: 0.36: : 1 preparing 300ml of hydrochloric acid-ammonium chloride aqueous solution, wherein the concentration of hydrochloric acid in the aqueous solution is 0.6mol/L, and the concentration of ammonium chloride in the aqueous solution is 0.3 mol/L.

Taking 50g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain molecular sieve slurry, and heating the molecular sieve slurry to 80 ℃. Based on 1L of molecular sieve slurry and H⁺And adding the prepared hydrochloric acid-ammonium chloride aqueous solution into the molecular sieve slurry at a constant speed for three times at a speed of 2mol/h, reacting for 4 hours at a constant temperature after each time of adding acid, filtering, and taking a filter cake to continue to add acid for the next time in the same manner. After the last time of acid addition and reaction for 4 hours, collecting a solid product, and drying at 180 ℃ for 3 hours to obtain a phosphorus-containing molecular sieve RY-3, Al of which²⁷The NMR structural spectrum is shown in FIG. 1, and the properties are shown in Table 1.

Preparation of comparative example 4

Taking 300g of PSRY molecular sieve (same as preparation example 2), adding deionized water for pulping, wherein the total amount of water is 1000ml, filtering, and drying at 70 ℃ for 2h to obtain the phosphorus-containing molecular sieve raw material with the water content of 65%.

And (3) putting the obtained phosphorus-containing molecular sieve raw material into a hydrothermal treatment device, heating to 580 ℃, controlling the pressure in the device to be 0.4MPa, performing hydrothermal treatment for 2 hours constantly, and taking out the molecular sieve material after the hydrothermal treatment.

According to the weight ratio of 0.8: 1 preparing 500ml of sulfuric acid aqueous solution, wherein the concentration of sulfuric acid in the aqueous solution is 0.2 mol/L.

Taking 50g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain molecular sieve slurry, and heating to 80 ℃. Adding the prepared sulfuric acid aqueous solution into the molecular sieve slurry for three times, wherein the acid adding mode for each time is directly pouring, then reacting for 2 hours at constant temperature, filtering, and taking the filter cake to continue to add acid for the next time according to the same mode. After the last time of acid addition and reaction for 2 hours, collecting a solid product, and drying at 100 ℃ for 8 hours to obtain a phosphorus-containing molecular sieve RY-4, Al of which²⁷The NMR structural spectrum is shown in FIG. 1, and the properties are shown in Table 1.

TABLE 1

As can be seen from table 1, the phosphorus-containing molecular sieve provided by the present disclosure has a higher ratio of the amount of the acid B to the amount of the acid L, and can improve the yield of the molecular sieve by connecting a filter to the outlet of the hydrothermal kettle, or by controlling the particle size range of the phosphorus-containing molecular sieve raw material.

Examples 1-4 are intended to illustrate catalysts prepared using the molecular sieves provided in this disclosure. Comparative examples 1-4 are presented to illustrate catalysts prepared using different molecular sieves than those of the present disclosure.

Example 1

583.3g of pseudo-boehmite powder PB90 (produced by Zhongpetrochemical catalyst ChangLing division, with a pore volume of 0.9ml/g and a water content of 28 wt%) and 98.8g Y-1 molecular sieve (with a water content of 19 wt%) and 18 g of sesbania powder are mixed uniformly, 580ml of aqueous solution containing 18ml of nitric acid (65-68 wt% in Beijing chemical reagent factory) is added, and the mixture is extruded into trilobal strips with a circumscribed circle diameter of 1.6 mm, dried at 120 ℃ and roasted at 600 ℃ for 3 hours to obtain the carrier CS-1.

After cooling to room temperature, 100g of the CS-1 carrier was immersed in 80ml of an aqueous solution containing 52 g of ammonium metatungstate (82 wt% tungsten oxide, available from Sichuan tribute carbide Co., Ltd.), 8.7 g of basic nickel carbonate (51 wt% nickel oxide, available from Jiangsuxing Xunxi chemical Co., Ltd.), and 10.5g of citric acid, and dried at 120 ℃ for 10 hours to obtain the catalyst prepared in this example.

Examples 2 to 4

A catalyst was prepared by the method of example 1 except that the molecular sieves used were Y-2, Y-3 and Y-4, respectively.

Comparative examples 1 to 4

A catalyst was prepared by the method of example 1 except that the molecular sieves used were RY-1, RY-2, RY-3 and RY-4, respectively.

Test examples

This test example was used to test the catalytic activity of the catalysts of examples 1 to 4 and comparative examples 1 to 4 for hydrocracking reactions. Wherein, the used raw oil is the Shashuaishui vacuum gas oil, and the physicochemical properties are shown in Table 2.

TABLE 2

Item	Raw oil
		Density (20 ℃ C.) (g/cm)³)	0.8885
S (wt%)	16000
		N(mg/L)	352
Simulated distillation (ASTM D-2887) (° C)
		Initial boiling point	291
50% by weight	391
		90% by weight	421

In the present test example, the evaluation method of the catalyst was: the catalyst was crushed into particles of 2 to 3 mm in diameter, 20 ml of the catalyst was charged into a30 ml fixed bed reactor, and before the reaction, the catalyst was first sulfurized with kerosene containing 2% by weight of carbon disulfide under a hydrogen atmosphere according to the following procedure, and then the reaction materials were switched to carry out the reaction.

And (3) vulcanization procedure: heating to 150 ℃, introducing vulcanized oil, keeping the temperature for 1h, allowing the adsorbed temperature wave to pass through two reactors, heating to 230 ℃ at the speed of 60 ℃/h, stabilizing for 2h, heating to 360 ℃ at the speed of 60 ℃/h, and stabilizing for 6 h. Replacing the raw oil, adjusting the reaction conditions below the reaction temperature, and stabilizing for at least 20 h.

Reaction conditions are as follows: at the reaction temperature of 365 ℃, the hydrogen partial pressure of 6.4MPa and the Liquid Hourly Space Velocity (LHSV) of 1h^-1The hydrocracking reaction was carried out under the condition that the hydrogen-oil ratio (volume) was 800. The results are shown in Table 3.

Conversion (%) - (% of fraction at more than 350 ℃ in the feed-fraction at more than 350 ℃ in the product oil)/amount of fraction at more than 350 ℃ in the feed X100%.

TABLE 3

Catalyst and process for preparing same	Conversion (%)
		Example 1	58.3
Example 2	62.1
		Example 3	61.1
Example 4	63.1
		Comparative example 1	34.3
Comparative example 2	38.2
		Comparative example 3	27.8
Comparative example 4	50.4

As can be seen from table 3, under the same reaction conditions, the catalytic activity of the catalyst containing the phosphorus-containing molecular sieve provided by the present disclosure is improved by 7.9 to 35.3% compared to the molecular sieve prepared by the conventional method.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. The phosphorus-containing molecular sieve is characterized in that the phosphorus content of the molecular sieve is 0.3-5 wt% calculated by oxides, the pore volume is 0.2-0.95 mL/g, the ratio of pyridine infrared B acid to L acid is 2-15, and Al of the molecular sieve is²⁷In NMR structural spectrum, I_60ppm/I_-1ppm5 to 15 of the above-mentioned Al²⁷Two characteristic peaks at 0ppm chemical shift of the NMR structural spectrum: the chemical shift of the first characteristic peak is-1 +/-1 ppm, the chemical shift of the second characteristic peak is-5.5 +/-2 ppm or 3-7 ppm, and the peak height ratio of the first characteristic peak to the second characteristic peak is I_-1ppm/I_±6ppmSaid I is_-1ppm/I_±6ppm0.4 to 2, wherein I_±6ppmTaking the larger value of peak height of-5.5 +/-2 ppm and 3-7 ppm.

2. The phosphorous containing molecular sieve of claim 1, wherein I is_-1ppm/I_±6ppm0.8 to 2.

3. A process for preparing the phosphorus-containing molecular sieve of claim 1 or 2, comprising:

a. putting the phosphorus-containing molecular sieve raw material into a hydrothermal kettle, and carrying out hydrothermal treatment for 0.5-10h at the temperature of 350-700 ℃ in the presence of water vapor to obtain a molecular sieve material after the hydrothermal treatment; the outlet of the hydrothermal kettle is connected with a filter, an open pipeline is arranged on the filter, inert particle fillers are arranged in the filter, and the pressure of hydrothermal treatment is 0.1-2 MPa; calculated by oxide and based on the dry weight of the phosphorus-containing molecular sieve raw material, the phosphorus content of the phosphorus-containing molecular sieve raw material is 0.1-15 wt%, and the sodium content is 0.5-4.5 wt%; the phosphorus-containing molecular sieve is a Y-type molecular sieve containing phosphorus;

4. The method according to claim 3, wherein in the step a, the inert particles are spherical, and the diameter of the inert particles is 1-100 mm.

5. The method according to claim 3, wherein in step a, the inert particles have a diameter of 3 to 30 mm.

6. The method according to claim 3, wherein in step a, the inert particles are made of at least one material selected from the group consisting of silica, alumina and zirconia.

7. The method of claim 3, wherein in the step a, the phosphorus-containing Y-type molecular sieve has a unit cell constant of 2.425 to 2.47nm and a specific surface area of 250 to 750m²The pore volume is 0.2 to 0.95 mL/g.

8. The method of claim 7, wherein in step a, the water content of the phosphorus-containing molecular sieve raw material is 10-40 wt%;

9. The method of claim 8, wherein the phosphorous-containing molecular sieve feedstock having a particle size range of 1mm to 500mm is present in an amount of 30 to 100 wt.% based on the total weight of the phosphorous-containing molecular sieve feedstock.

10. The method of claim 9, wherein the phosphorus-containing molecular sieve feedstock having a particle size in the range of 5mm to 100mm is present in an amount of 30 to 100 wt% based on the total weight of the phosphorus-containing molecular sieve feedstock.

11. The method of claim 3, wherein in step b, the weight of water in the molecular sieve slurry obtained after beating and the dry basis weight of the phosphorus-containing molecular sieve feedstock are in a ratio of (14-5): 1.

12. the method according to claim 3, wherein in the step b, the acid solution has an acid concentration of 0.01 to 15.0mol/L, and the acid is at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid and formic acid.

13. The method according to claim 3, wherein the acid solution is added in step b by: based on 1L of the molecular sieve slurry, taking H as the reference⁺The acid solution is added to the molecular sieve slurry at a rate of 0.05 to 10 moles/hour.

14. The method of claim 3 or 13, wherein the method further comprises: in the step b, adding ammonium salt into the molecular sieve slurry in the process of adding the acid solution, wherein the ammonium salt is at least one selected from ammonium nitrate, ammonium chloride and ammonium sulfate, and the weight ratio of the ammonium salt to the dry basis weight of the phosphorus-containing molecular sieve raw material is (0.1-2.0): 1.

15. the method of claim 3, wherein the method further comprises: collecting the solid product, then washing with water and drying to obtain a phosphorus-containing molecular sieve; the drying conditions are as follows: the temperature is 50-350 ℃; the time is 1-24 h.

16. The method according to claim 15, wherein the drying temperature is 70 to 200 ℃.

17. The method according to claim 15, wherein the drying time is 2-6 h.

18. Use of a phosphorus-containing molecular sieve as claimed in claim 1 or 2 in a hydrocracking reaction of a hydrocarbon feedstock.

19. The use according to claim 18, wherein the hydrocarbon feedstock is at least one selected from the group consisting of straight run gas oil, vacuum gas oil, demetallized oil, atmospheric residue, deasphalted vacuum residue, coker distillate, catalytically cracked distillate, shale oil, tar sand oil, and coal liquefied oil;

the conditions of the hydrocracking reaction are as follows: the reaction temperature is 200-650 ℃; the reaction pressure is 3-24 MPa; the liquid hourly space velocity is 0.1-10 hours^-1(ii) a The volume ratio of hydrogen to oil is 100-5000.

20. The use as claimed in claim 18, wherein the reaction temperature of the hydrocracking reaction is 300-510 ℃.

21. Use according to claim 18, wherein the hydrocracking reaction is carried out at a reaction pressure of 4-15 mpa.

22. The use of claim 18, wherein the liquid hourly space velocity of the hydrocracking reaction is in the range of 0.2 to 5 hours^-1。

23. The use as claimed in claim 18, wherein the hydrogen to oil volume ratio of the hydrocracking reaction is 200-1000.