CN110841701B

CN110841701B - Combined catalyst and white oil production method

Info

Publication number: CN110841701B
Application number: CN201810948148.6A
Authority: CN
Inventors: 毕云飞; 夏国富; 郭庆洲; 方文秀; 李洪辉
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: 2018-08-20
Filing date: 2018-08-20
Publication date: 2021-12-17
Anticipated expiration: 2038-08-20
Also published as: CN110841701A

Abstract

The invention relates to a combined catalyst and a white oil production method, the combined catalyst comprises a first catalyst and a second catalyst, wherein the first catalyst contains a ten-membered ring molecular sieve M1, the second catalyst contains a twelve-membered ring molecular sieve M2, and the first catalyst and the second catalyst are respectively filled in different reactors; wherein the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 has the following characteristics: the molar ratio of silicon oxide to aluminum oxide is 120-300; contains a mesoporous structure and has a closed hysteresis loop at a low-temperature nitrogen adsorption-desorption curve P/P0-0.4-0.99, and the starting position of the closed hysteresis loop is at a position P/P0-0.4-0.7. The method of the invention is adopted to produce white oil, and better aromatic saturation effect can be obtained.

Description

Combined catalyst and white oil production method

Technical Field

The invention relates to the field of white oil hydrotreatment, in particular to a combined catalyst and a white oil production method.

Background

The molecular sieve material has high acidity and high specific surface area, and is an excellent acidic catalyst. Meanwhile, the molecular sieve material has strong chemical stability and hydrothermal stability, and is difficult to be corroded and dissolved by reactants to be damaged. Compared with the commonly used homogeneous catalyst, the molecular sieve material catalyst can be directly recycled without separation, and simultaneously, the environmental pollution and the product pollution are avoided. The specific surface area and other pore structure parameters of the molecular sieve material have important influence on the catalytic performance of the molecular sieve, so that the preparation of the molecular sieve with special pores is an important research direction in the chemical field.

CN104353484A discloses a preparation method of a cheap strong-acid hierarchical pore Beta zeolite, relating to a preparation method of a hierarchical pore Beta zeolite. The invention aims to solve the problem of acidity weakening of the existing desilication post-treatment hierarchical pore Beta zeolite molecular sieve. The method comprises the following steps: (1) calcining Beta zeolite to obtain microporous hydrogen type Beta zeolite; (2) adding the microporous hydrogen type Beta zeolite into an alkaline solution, stirring, washing and drying to obtain sodium type desiliconized hierarchical porous Beta zeolite; (3) adding the sodium desiliconized hierarchical pore Beta zeolite into an ammonium nitrate aqueous solution for exchange, and calcining to obtain hydrogen desiliconized hierarchical pore Beta zeolite; (4) and (3) adding the hydrogen-type desiliconized hierarchical pore Beta zeolite into an acid solution, stirring, washing, drying, and then repeating the step (3) to obtain the strong-acid hierarchical pore Beta zeolite.

CN103073020A discloses a hierarchical pore zeolite molecular sieve and a preparation method and application thereof. The preparation method specifically comprises the following steps: the method for preparing the hierarchical zeolite molecular sieve by assembling silanized zeolite seed crystals under hydrothermal conditions by using a cationic surfactant as a template. The method overcomes the problem that the multistage pore zeolite cannot be prepared due to the mismatching between the conventional cationic surfactant and the zeolite template. The prepared material realizes the composition of micropores and mesopores, and is a highly crystallized multi-level pore channel zeolite molecular sieve. In the method, substantially, organosilane is grafted to a seed crystal by utilizing a specific functional group reaction, and is matched with a cationic surfactant to prepare a mesoporous molecular sieve, wherein mesopores are formed by guiding the cationic surfactant, and the mesopores with the aperture of about 2.4nm are formed by utilizing the hard template action of the organosilane. The seed crystal selected in the invention is microporous molecular sieve, which is added into a preparation system after silanization, the hydrophobic property of the seed crystal is utilized to increase the effect of the seed crystal on the hydrophobic end of a surfactant micelle so as to reduce the interaction between two guiding agents, but the formed mesopores still do not have a regular structure, and whether the addition of the seed crystal reduces the dosage of a template agent is not reported.

CN104891526A discloses a preparation method of a mesoporous molecular sieve with high hydrothermal stability. The method comprises the following steps: (1) preparing a first Y-type molecular sieve precursor: (2) and (3) crystallization: adding seed crystals into a first Y-type molecular sieve precursor, adjusting the pH value to 0.5-5, stirring at 20-50 ℃ for 10-24 h, aging at 20-50 ℃ for 2-24 h to obtain an assembled product, transferring the assembled product into a microreactor with a polytetrafluoroethylene lining, transferring the assembled product and the reactor into an autoclave, crystallizing at 100-200 ℃ for 10-48 h, filtering, washing and drying to obtain the high-stability mesoporous molecular sieve. Firstly, a precursor of the microporous molecular sieve is prepared, the mesoporous-microporous molecular sieve is used for preparing the mesoporous molecular sieve as a seed crystal, two methods of molecular sieve precursor assembly and seed crystal are combined, and the mesoporous molecular sieve with high stability is obtained under the condition of not using an organic template agent. Not only greatly reduces the preparation cost of the molecular sieve, but also saves the process of calcining the template agent and reduces the energy consumption.

CN102050459A discloses a method for preparing a high-silicon molecular sieve, wherein the method comprises flowing the molecular sieve with an inert carrier gas under the carrying of the inert carrier gas flow, and mixing with gas-phase SiCl₄Contacting molecular sieve with gas-phase SiCl in a flowing state₄The contact time of (a) is from 10 seconds to 100 minutes. The method for preparing the high-silicon molecular sieve can realize the molecular sieve and SiCl₄The contact reaction of (2) is continuously carried out, and the molecular sieve and SiCl can be controlled by controlling the flow rate of the carrier gas and the length of the tubular reactor₄The time of contact, thereby enabling the molecular sieve to be contacted with SiCl₄The contact reaction of (2) is sufficiently carried out in the tubular reactor.

CN1703490A discloses a catalyst combination method for producing lube base oil. The invention relates to a process for converting waxes containing heavy components to high quality lube basestocks by using a linear mesoporous molecular sieve having a near circular pore structure with an average diameter of 0.50nm to 0.65nm, wherein the difference between the maximum and minimum diameters is 0.05nm or less, followed by a molecular sieve beta zeolite catalyst. Both catalysts comprise one or more group VIII metals. For example, a cascaded two-bed catalyst system consisting of a first bed Pt/ZSM-48 catalyst followed by a second bed Pt/beta catalyst facilitates the treatment of heavy lube oils.

CN1803998A discloses a dewaxing catalyst containing a composite molecular sieve, which contains a molecular sieve with a one-dimensional mesoporous structure and a molecular sieve with a macroporous structure, wherein the weight ratio of the molecular sieve with the one-dimensional mesoporous structure to the molecular sieve with the macroporous structure is 80-99: 1-20, the molecular sieve with the macroporous structure contains non-framework silicon, and the content of the silicon is 1-20 wt% calculated by oxide and based on the molecular sieve.

Disclosure of Invention

The invention aims to provide a combined catalyst and a method for producing white oil.

In order to achieve the above object, the present invention provides a combined catalyst comprising a first catalyst containing a ten-membered ring molecular sieve M1 and a second catalyst containing a twelve-membered ring molecular sieve M2, the first and second catalysts each independently containing an active metal component and the first and second catalysts being packed in different reactors, respectively;

wherein the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 has the following characteristics: the molar ratio of silicon oxide to aluminum oxide is 120-300; contains a mesoporous structure and has a closed hysteresis loop at a low-temperature nitrogen adsorption-desorption curve P/P0-0.4-0.99, and the starting position of the closed hysteresis loop is at a position P/P0-0.4-0.7.

Optionally, in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2, the molecular sieve has a silica/alumina molar ratio of 150-.

Optionally, in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2, the mesoporous area of the molecular sieve is 50M²/g-250m²The proportion of the mesoporous area in the specific surface area is 20-70%, preferably 25-65%.

Optionally, in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2, the start position of the closed hysteresis loop is at P/P0 ═ 0.4 to 0.6.

Optionally, the amount of penta-coordinated aluminum in the precursor of the molecular sieve in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 is 4 to 30 wt%, preferably 10 to 30 wt%, calculated as oxide and based on the total alumina amount of the molecular sieve.

Optionally, in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2, the amount of penta-coordinated aluminum in the final molecular sieve is 3 wt% or less, preferably 1 wt% or less, and more preferably no penta-coordinated aluminum, calculated as oxide and based on the total alumina amount of the molecular sieve.

Alternatively, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 is prepared according to the following steps:

(1) filtering the crystallized mother liquor to form a filter cake with the dry basis content of 5-30%;

(2) directly roasting the filter cake to obtain a molecular sieve precursor;

(3) subjecting the molecular sieve precursor to a hydrothermal treatment;

(4) and filtering, washing and drying the hydrothermal treatment product.

Optionally, in step (1), the filter cake formed by the filtration has a dry content of 6-15%.

Optionally, in the step (2), the temperature of the calcination is 400-.

Optionally, in the step (3), the medium for the hydrothermal treatment is acidic water;

preferably, the acidic water contains inorganic acid and/or organic acid, and the content of the inorganic acid and/or organic acid is 0.1M-5M, preferably 0.2M-2M;

more preferably, the acidic water contains at least one of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, citric acid, acetic acid, maleic acid, oxalic acid, nitrilotriacetic acid, 1, 2-cyclohexanediaminetetraacetic acid, tartaric acid, and malic acid.

Optionally, in the step (3), the liquid-solid volume ratio of the hydrothermal treatment is 5-200, preferably 20-100; the temperature of the hydrothermal treatment is 100-300 ℃, and preferably 100-200 ℃; the time of the hydrothermal treatment is 0.5 to 24 hours, preferably 1 to 12 hours, and more preferably 1 to 4 hours;

preferably, the hydrothermal treatment is carried out in a closed container, and the pressure of the hydrothermal treatment is the autogenous pressure of the closed container under the hydrothermal condition.

Optionally, in the step (4), the washing process is water washing with deionized water, and the water washing is completed until the pH value of the filtrate is 6-8, preferably 6-7.

Optionally, the reactor filled with the first catalyst is located upstream or downstream of the reactor filled with the second catalyst, according to the flow direction of the reaction mass.

Optionally, the ten-membered ring molecular sieve M1 is selected from one or more of ZSM-22, ZSM-48, ZSM-5 and SSZ-32, and the twelve-membered ring molecular sieve M2 is selected from one or more of ZSM-12 molecular sieve, beta molecular sieve, Y molecular sieve, USY molecular sieve and LaY molecular sieve.

Optionally, the difference between the silica/alumina molar ratio of the ten-membered ring molecular sieve M1 and the silica/alumina molar ratio of the twelve-membered ring molecular sieve M2 is 5 to 60, preferably 20 to 40.

Optionally, the loading weight ratio of the first catalyst to the second catalyst is 1: (0.1-1.0);

the active metal component is Pt;

the first catalyst also comprises a refractory inorganic oxide, wherein the content of the ten-membered ring molecular sieve M1 is 20-80 wt%, preferably 25-55 wt%, and the content of the active metal component is 0.1-5 wt%, preferably 0.2-3 wt%, more preferably 0.4-1 wt%, based on the weight of the first catalyst;

the second catalyst also comprises a refractory inorganic oxide, the twelve-membered ring molecular sieve M2 is present in an amount of 20 to 80 wt.%, preferably 25 to 55 wt.%, and the active metal component is present in an amount of 0.1 to 5 wt.%, preferably 0.2 to 3 wt.%, more preferably 0.4 to 1 wt.%, based on the weight of the second catalyst.

The invention also provides a method for producing white oil, which comprises the step of injecting the white oil raw material into a reaction device for hydrotreating, wherein the catalyst filled in the reaction device contains the combined catalyst provided by the invention.

Optionally, the distillation range of the white oil raw material is 100-600 ℃;

the hydrotreating conditions for the different reactors independently comprise: the temperature is 100-500 ℃, preferably 200-400 ℃, and more preferably 220-300 ℃; the pressure is 1-30MPa, preferably 2-20MPa, more preferably 5-20 MPa; the volume space velocity is 0.1-5h^-1Preferably 0.1 to 3h^-1More preferably 0.5 to 2 hours^-1(ii) a The volume ratio of the hydrogen to the oil is 50-3000, preferably 300-3000, more preferably 400-600.

According to the method for producing the white oil, the two catalysts containing the molecular sieve with special physicochemical properties are combined and used in different reactors, so that a better aromatic saturation effect can be obtained.

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

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic structural view of one embodiment of a reaction apparatus used in the method of the present invention.

Description of the reference numerals

1 first reactor 2 second reactor

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The combined catalyst comprises a first catalyst and a second catalyst, wherein the first catalyst contains a ten-membered ring molecular sieve M1, and the second catalyst contains a twelve-membered ring molecular sieve M2.

In the combined catalyst, at least one of the ten-membered ring molecular sieve M1 and the twelve-membered ring molecular sieve M2 is high in silicon and contains mesopores. Preferably, both the ten-membered ring molecular sieve M1 and the twelve-membered ring molecular sieve M2 have the characteristics of being high in silicon and containing mesopores.

Preferably, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 are high in silicon. The ten-and twelve-membered ring molecular sieves prepared according to conventional methods in the art typically have a silica to alumina mole ratio of less than 100. The mole ratio of silica/alumina of the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 in the present invention is 120-300, and specifically, may be, for example, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 or any value in the range defined by any two of these values. Preferably, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 have a silica/alumina molar ratio of 150-200.

Preferably, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 according to the present invention have a mesoporous structure. The ten-membered ring molecular sieves and the twelve-membered ring molecular sieves prepared according to the conventional methods in the art are generally microporous molecular sieves and do not contain a mesoporous structure. On the low temperature nitrogen adsorption-desorption curves of the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 of the present invention, the adsorption branch and the desorption branch show a closed hysteresis loop at P/P0 ═ 0.4 to 0.99, and the start position of the closed hysteresis loop is at P/P0 ═ 0.4 to 0.7, whereas the ten-membered ring molecular sieve and the twelve-membered ring molecular sieve prepared by the prior art do not have this feature, i.e., no hysteresis loop or the start position of the hysteresis loop appears at higher partial pressures in this interval (typically at P/P0> 0.7). Preferably, the start position of the closed hysteresis loop is at P/P0-0.4-0.6.

Preferably, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 are/is characterized by a nitrogen adsorption BET (Brunner-Emmet-Teller) method, and the mesoporous area in the molecular sieve can be 50M²/g-250m²The specific surface area of the molecular sieve can be 150m²/g-400m²The proportion of the mesoporous area to the specific surface area can be 20-70%, preferably 25-65%.

Preferably, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 of the present invention, which have the characteristics of high silicon, mesoporous, and closed hysteresis rings, are rich in penta-coordinated aluminum in the precursor, while the amount of penta-coordinated aluminum in the final molecular sieve is very small, even substantially free of penta-coordinated aluminum. Specifically, the content of penta-coordinated aluminum in the precursor of the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 is 4 to 30% by weight, preferably 10 to 30% by weight; and the penta-coordinated aluminum content in the finished molecular sieve is 3% by weight or less, preferably 2.5% by weight or less, more preferably 2% by weight or less, even more preferably 1% by weight or less, even more preferably 0.5% by weight or less, and most preferably no penta-coordinated aluminum is contained.

Generally, the preparation of the aluminum-containing molecular sieve can be divided into steps of colloid formation, crystallization, post-treatment and the like. In order to obtain the high-silicon and mesoporous-containing ten-membered ring molecular sieve M1 and/or twelve-membered ring molecular sieve M2, a post-treatment step in the synthesis process of the aluminum-containing molecular sieve needs to be specially treated. Preferably, the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 is prepared according to the following steps:

(1) filtering the crystallized mother liquor to form a filter cake with the dry basis content of 5-30 wt%;

(2) directly roasting the filter cake to obtain a molecular sieve precursor;

(3) subjecting the molecular sieve precursor to a hydrothermal treatment;

(4) and filtering, washing and drying the hydrothermal treatment product.

In the step (1), the mother liquor after crystallization is filtered for the purpose of removing the synthesis mother liquor. The invention is particularly limited with respect to the dry content of the filter cake formed by filtration. In particular, the filter cake has a dry content of 5 to 30% by weight, preferably 6 to 15% by weight. When the dry basis content in the filter cake is out of the above range, the physicochemical properties of the prepared molecular sieve are out of the range defined by the present invention. In the present invention, "dry basis" is defined as: the mass percentage of the material after roasting at 600 ℃ for 4 hours to the mass of the material before roasting.

In the step (2), the filter cake formed in the step (1) is directly roasted at a high temperature without being dried. In the present invention, the temperature of the calcination may be 400-600 ℃, preferably 450-550 ℃. The heating rate during the calcination can be 10-100 deg.C/min, preferably 20-50 deg.C/min. The calcination time may be 1 hour to 12 hours, preferably 2 hours to 6 hours. The roasting environment can be a natural environment, namely oxygen-containing gas is not required to be specially introduced during roasting. Even if the calcination is carried out in the natural environment, the water in the filter cake can oxidize the template agent and can react with the aluminum in the molecular sieve to form non-framework aluminum. In particular, the product treated by step (2) in the present invention (i.e., the molecular sieve precursor) contains a significant amount of penta-coordinated non-framework aluminum (i.e., penta-coordinated aluminum). Penta-coordinated non-framework aluminum is defined as²⁷The chemical shift Be in the Al NMR spectrum is a peak of 15-40 ppm.²⁷Al NMR spectroscopic measurement conditions can be found in publications such as Guoling Zhao et Al, Applied Catalysis A: General 299(2006) 167-.

In the present invention, the amount of penta-coordinated aluminum in the product treated in step (2) (i.e., the molecular sieve precursor) is 4 to 30% by weight, preferably 10 to 30% by weight; in the step (2), the sample after the roasting treatment can be naturally cooled, and the target temperature is preferably room temperature.

In step (3), the medium for the hydrothermal treatment is preferably acidic water. In the present invention, the acidic water means containing H⁺H of (A) to (B)₂And (4) O solution. Wherein H₂O is a conventional process to obtain a liquid material called "water". H⁺Is the ion released by the dissociation of organic acid and/or inorganic acid. To obtain the acidic water, hydrochloric acid, sulfuric acid, phosphoric acid may be added to the "waterAt least one of nitric acid, citric acid, acetic acid, maleic acid, oxalic acid, nitrilotriacetic acid, 1, 2-cyclohexanediaminetetraacetic acid, tartaric acid and malic acid, preferably hydrochloric acid and/or citric acid. The content of the inorganic acid and/or the organic acid in the acidic water can be 0.1M-5M, preferably 0.2M-2M.

In step (3), the liquid-solid volume ratio of the hydrothermal treatment may be 5 to 200, preferably 20 to 100; in the step (3), the temperature of the hydrothermal treatment may be 100 to 300 ℃, preferably 100 to 200 ℃; in step (3), the time of the hydrothermal treatment may be 0.5 to 24 hours, preferably 1 to 12 hours, more preferably 1 to 4 hours; in step (3), the hydrothermal treatment is preferably performed in a closed vessel, and the pressure of the hydrothermal treatment is preferably the autogenous pressure of the closed vessel under the hydrothermal conditions.

In the step (4), the molecular sieve is required to be filtered and washed after being treated in the step (3). Among them, the filtration method may be a method known to those skilled in the art. The washing process can be water washing with deionized water, and the water washing is finished until the pH value of the filtrate is 6-8, preferably 6-7. The pH measurement of the solution may be performed using pH paper or a pH meter, and the measurement method is well known to those skilled in the art.

In the step (4), the drying treatment of the molecular sieve is not particularly limited, and may be carried out, for example, by drying at 120 ℃ for 6 hours in accordance with a conventional method.

In the present invention, the mother liquid after crystallization can be prepared according to the conventional method in the art, for example, when the ten-membered ring molecular sieve is ZSM-22 molecular sieve, the mother liquid after crystallization can be prepared according to the method disclosed in the document O.Murazaet, Microporous and Mesoporous Materials 206(2015) 136-143. When the decacycloaluminosilicate molecular sieve is ZSM-48 molecular sieve, the preparation method of the mother liquor after crystallization can be referred to the literature P.Me' riaudeau et al/Journal of Catalysis,1999(185), 435-444, or the U.S. patent application No. 5961951. In one embodiment, the process for preparing the crystallized mother liquor comprises: preparing silicon-containing solution, aluminum-containing solution and alkaline liquid, mixing the above-mentioned liquids, making colloid, then making crystallization at a certain temperature.

In the combined catalyst of the present invention, the arrangement of the first catalyst and the second catalyst is not particularly limited. The reactor filled with the first catalyst is located upstream or downstream of the reactor filled with the second catalyst, according to the flow direction of the reaction mass. Specifically, the first catalyst may be disposed in a first reactor and the second catalyst disposed in a second reactor along the flow direction of the reactant stream, such that the reactant first contacts and reacts with the first catalyst and then contacts and reacts with the second catalyst; alternatively, the second catalyst may be disposed in a first reactor, and the first catalyst may be disposed in a second reactor, such that the reaction material first contacts and reacts with the second catalyst and then contacts and reacts with the first catalyst; or the first catalyst and the second catalyst are arranged in a staggered way, so that the reaction materials are sequentially and alternately in contact reaction with the first catalyst and the second catalyst.

In the combined catalyst of the present invention, the loading weight ratio of the first catalyst to the second catalyst is preferably 1: 0.1 to 10, more preferably 1: 1-2.5, more preferably 1: 1-2.

In the present invention, the weight ratio of the first catalyst to the second catalyst means the weight ratio of the first catalyst distributed in all the reactor catalyst beds to the second catalyst distributed in all the reactor catalyst beds.

In the combined catalyst of the present invention, the types of the twelve-membered ring molecular sieve and the ten-membered ring molecular sieve are not particularly limited, for example, the ten-membered ring molecular sieve M1 is selected from one or more of ZSM-22, ZSM-48, ZSM-5 and SSZ-32, and the twelve-membered ring molecular sieve M2 is selected from one or more of ZSM-12 molecular sieve, beta molecular sieve, Y molecular sieve, USY molecular sieve and LaY molecular sieve. Preferably, the twelve-membered ring molecular sieve M2 is a ZSM-12 molecular sieve and/or a beta molecular sieve.

In the combined catalyst of the present invention, in order to further improve the effect of the combined catalyst, the difference between the molar ratio of silica/alumina of the ten-membered ring molecular sieve M1 and the molar ratio of silica/alumina of the twelve-membered ring molecular sieve M2 is preferably 5 to 60, and specifically may be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or any value in the range of any two of these values. More preferably, the difference is 20-40.

In the combined catalyst of the present invention, the first catalyst may be a supported catalyst, and the preparation process may include: the ten-membered ring molecular sieve M1 is mixed with a refractory inorganic oxide, formed, and then loaded with an active metal component, for example, by impregnation, followed by activation and reduction.

In the combined catalyst of the present invention, the second catalyst may be a supported catalyst, and the preparation process may include: the twelve-membered ring molecular sieve M2 is mixed with a refractory inorganic oxide, shaped, and then loaded with an active metal component, for example, by impregnation, and then subjected to activation and reduction.

In the present invention, the heat-resistant inorganic oxide is preferably alumina.

In the present invention, the first catalyst and the second catalyst further optionally include an active metal component, which may be a group VIII metal component. Group VIII metals such as Ru, Os, Rh, Ir, Pd and Pt. Preferably, the group VIII metal is selected from Pd and/or Pt, more preferably Pt.

In the present invention, the content of the molecular sieve (ten-membered ring molecular sieve M1 or twelve-membered ring molecular sieve M2) in the first catalyst and the second catalyst may be 20 to 80% by weight, preferably 25 to 55% by weight, based on the total weight of the catalysts; the content of the heat-resistant inorganic oxide (such as alumina) is 35 to 80 wt%, preferably 42 to 72 wt%; the content of the active metal component is 0.1 to 5% by weight, preferably 0.2 to 3% by weight, more preferably 0.4 to 1% by weight.

The method for producing the white oil comprises the step of injecting the white oil into a reaction device for hydrotreating, wherein the catalyst filled in the reaction device is the combined catalyst provided by the invention, and the reaction device at least comprises two reactors.

In the present invention, the distillation range of the white oil can be generally 100-.

In the method of the present invention, the hydrotreating is not particularly limited as long as it is sufficient to cause a hydrogenation saturation reaction of the white oil. Generally, the reaction conditions may include: the temperature is 100-500 ℃, preferably 200-400 ℃, and more preferably 220-300 ℃; a pressure of 1 to 30MPa, preferably 2 to 20MPa, more preferably 5 to 20MPa, the pressure referred to herein being an absolute pressure; the volume space velocity is 0.1-5h^-1Preferably 0.1 to 3h^-1More preferably 0.5 to 2 hours^-1(ii) a The volume ratio of the hydrogen to the oil is 50-3000, preferably 300-3000, more preferably 400-600. The first catalyst and the second catalyst are respectively filled in different reactors, and the reaction conditions of the different reactors can be adjusted according to the factors such as catalyst activity and the like to optimize the reaction effect, namely the hydrotreating conditions of the different reactors can be the same or different.

The method of the invention contacts the white oil raw material with the combined catalyst of the invention, and can obtain higher yield of aromatic saturated products.

The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.

In the following examples and comparative examples, the content of each element in the measurement sample was analyzed and measured by a 3271E type X-ray fluorescence spectrometer commercially available from Nippon chemical and electric machines industries, and the sample was baked at 600 ℃ for 3 hours before the measurement.

In the following examples and comparative examples, the specific surface area, the external surface area and the nitrogen adsorption-desorption curve of a sample were measured by using an automatic adsorption apparatus model DIGISORB 2500 of Micromeritics, USA, and the sample was baked at 600 ℃ for 3 hours before the test, and the measurement method was performed according to the ASTM D4222-98 standard method.

In the following examples and comparative examples, dry basis means the percentage of the weight of the product obtained after calcination of a certain amount of material in a muffle furnace at 600 ℃ for 4 hours in an air atmosphere, to the weight of the material before calcination. I.e. dry basis (weight of product obtained after calcination ÷ weight of material before calcination) × 100%.

Preparation example 1

(1) Preparation of crystallized mother liquor

36.3 g of a 40% by weight SiO solution were taken₂1.77 g of analytically pure Al₂(SO₄)₃·18H₂O, 3.94 g of analytically pure KOH and 8.44 g of hexamethylenediamine are used. Mixing hexamethylenediamine with silica sol, adding KOH and Al₂(SO₄)₃·18H₂O and 89.4 g of deionized water, then mixing the two solutions, stirring for 1 hour, transferring the mixture into a reaction kettle, and crystallizing for 72 hours at 160 ℃.

(2) Preparation of the Filter cake

Filtering the crystallized mother liquor prepared in the step (1), and continuing to pump and filter for 5 minutes when no filtrate exists on a filter cake to obtain a filter cake F-1, wherein the dry content of the filter cake F-1 is 11.2 wt%, and the molar ratio of silicon oxide to aluminum oxide is 60.

(3) Preparation of molecular Sieve precursors

The filter cake F-1 was warmed from room temperature to 450 ℃ at a temperature rise rate of 25 ℃ per minute and held at that temperature for 4 hours. And in the temperature rising process, the roasting furnace is a closed roasting furnace, and the molecular sieve precursor C-1 is obtained.

(4) Preparation of molecular sieve finished product

Putting the molecular sieve precursor C-1 into a HCl solution with the concentration of 1M for closed hydrothermal treatment. Wherein, the liquid-solid volume ratio is 50, the temperature of the hydrothermal treatment is 180 ℃, the time of the hydrothermal treatment is 3 hours, after the hydrothermal treatment is finished, the product is filtered and washed until the pH value of the filtrate is 7, and after the filtrate is dried for 4 hours at 120 ℃, the product is roasted for 4 hours at 550 ℃, and the finished product H-1 of the ZSM-22 molecular sieve is obtained. As can be seen from the nitrogen adsorption-desorption curve (measured by the BET method) of the molecular sieve, the ZSM-22 molecular sieve shows a closed hysteresis loop at a low-temperature nitrogen adsorption-desorption curve P/P0 of 0.4 to 0.99, and the start position of the closed hysteresis loop is at a P/P0 of 0.4 to 0.5.

(5) Preparation of the catalyst

40g (dry basis) of molecular sieve H-1 was ground to 120 mesh and then mixed with 60g (dry basis) of alumina, shaped, calcined at 560 ℃ and loaded with 0.4 wt% of metallic Pt. Activating for 3h at 400 ℃, and reducing for 3h at 400 ℃ to prepare the catalyst, which is named as Cat-1.

Preparation of comparative example 1

A ZSM-22 molecular sieve and a catalyst were prepared according to the method of preparation example 1, except that, in the step (2), when there was no filtrate on the filter cake, the suction filtration was continued for 50 minutes to obtain a filter cake DF-1, the dry content of which filter cake DF-1 was 46.5% by weight. To prepare a ZSM-22 molecular sieve finished product DH-1 and a catalyst D-Cat-1.

Preparation of comparative example 2

The mother liquor after crystallization was prepared according to procedure (1) of preparation example 1, followed by filtration, and the filter cake obtained after filtration was dried at 120 ℃ for 6 hours and then calcined at 550 ℃ for 4 hours to obtain a solid product and NH₄Exchanging Cl for 3 times, and drying to form the ammonium molecular sieve finished product DH-2. Then, catalyst D-Cat-2 was prepared using molecular sieve DH-2 and following the procedure of preparation example 1.

Preparation example 2

(1) Preparation of crystallized mother liquor

38.5mL of a 40 wt.% SiO solution was taken₂1.48 g of analytically pure sodium aluminate, and 17.5mL of tetraethylammonium hydroxide (40% by weight) were used. Tetraethyl ammonium hydroxide and sodium aluminate were mixed with 37 g of deionized water, and then the silica sol was added, stirred for 1 hour, transferred to a reaction kettle, and crystallized at 160 ℃ for 132 hours.

(2) Preparation of the Filter cake

Filtering the crystallized mother liquor prepared in the step (1), and continuing to pump and filter for 5 minutes when no filtrate exists on a filter cake to obtain a filter cake F-2, wherein the dry content of the filter cake F-2 is 11.2 weight percent, and the molar ratio of silicon oxide to aluminum oxide is 60.

(3) Preparation of molecular Sieve precursors

The filter cake F-2 was warmed from room temperature to 450 ℃ at a temperature rise rate of 25 ℃/min and held at that temperature for 4 hours. And in the temperature rising process, the roasting furnace is a closed roasting furnace, and the molecular sieve precursor C-2 is obtained.

(4) Preparation of molecular sieve finished product

And putting the molecular sieve precursor C-2 into a 1M HCl solution for closed hydrothermal treatment. Wherein, the liquid-solid volume ratio is 50, the temperature of the hydrothermal treatment is 180 ℃, the time of the hydrothermal treatment is 3 hours, after the hydrothermal treatment is finished, the product is filtered and washed until the pH value of the filtrate is 7, and after the filtrate is dried for 4 hours at 120 ℃, the product is roasted for 4 hours at 550 ℃, and the finished product H-2 of the ZSM-12 molecular sieve is obtained. As can be seen from the nitrogen adsorption-desorption curve (measured by the BET method) of the molecular sieve, the ZSM-12 molecular sieve shows a closed hysteresis loop at the low-temperature nitrogen adsorption-desorption curve P/P0 of 0.4 to 0.99, and the start position of the closed hysteresis loop is at the P/P0 of 0.4 to 0.5.

(5) Preparation of the catalyst

40g (dry basis) of molecular sieve H-2 was ground to 120 mesh and then mixed with 60g (dry basis) of alumina, shaped, calcined at 560 ℃ and loaded with 0.4 wt% of metallic Pt. Activating for 3h at 400 ℃, and reducing for 3h at 400 ℃ to prepare the catalyst, which is named as Cat-2.

Test example 1

(1) The mesoporous area and the specific surface area (measured by the BET method) of the molecular sieve products prepared in the above preparation examples and preparation comparative examples were measured by using an automatic adsorption apparatus model DIGISORB 2500, Micromeritics, usa, and the ratio of the mesoporous area to the specific surface area was calculated, and the results are shown in table 1 below.

(2) The contents of the respective elements in the molecular sieve precursors and the molecular sieve finished products prepared in the above preparation examples and preparation comparative examples were analyzed and measured by a 3271E type X-ray fluorescence spectrometer commercially available from japan physical and electrical machinery industries, and the silicon-aluminum ratio and the content of penta-coordinated aluminum were determined, and the results are shown in table 1 below.

Example 1

As shown in FIG. 1, 50g of catalyst Cat-1 and 150g of catalyst Cat-2 were placed in a first reactor 1 and a second reactor 2 of a high-pressure hydrogenation reaction apparatus, respectively. The white oil raw materials (parameters shown in Table 2) were fed into the reactor from top to bottom to react under the conditions shown in Table 3 below. And (3) after the reaction is finished, performing ultraviolet light absorption characterization on the product (ASTM D2008-91), wherein the lower the absorbance is, the lower the content of the aromatic hydrocarbon in the oil product is.

Comparative example 1

A white oil was produced according to the method of example 1, except that the first reactor and the second reactor of the high-pressure hydrogenation reaction apparatus were filled with the catalyst D-Cat-1 and the catalyst D-Cat-2, respectively, in respective weights.

Comparative example 2

A white oil was produced according to the method of example 1, except that the high-pressure hydrogenation reaction apparatus was charged with only 200g of the catalyst D-Cat-1.

Comparative example 3

A white oil was produced according to the method of example 1, except that the high-pressure hydrogenation reaction apparatus was charged with only 200g of the catalyst D-Cat-2.

Example 2

A white oil was produced according to the method of example 1, except that the first reactor of the high-pressure hydrogenation reaction apparatus was charged with a corresponding weight of catalyst D-Cat-1 in place of the catalyst Cat-1.

Example 3

A white oil was produced according to the method of example 1, except that the second reactor of the high-pressure hydrogenation reaction apparatus was charged with the corresponding weight of the catalyst D-Cat-2 in place of the catalyst Cat-2.

Example 4

A white oil was produced according to the method of example 1, except that 100g of the catalyst Cat-1 and 100g of the catalyst Cat-2 were charged in the first reactor and the second reactor of the high-pressure hydrogenation reaction apparatus, respectively.

Example 5

A white oil was produced according to the method of example 1, except that 150g of the catalyst Cat-1 and 50g of the catalyst Cat-2 were charged in the first reactor and the second reactor of the high-pressure hydrogenation reaction apparatus, respectively.

Example 6

A white oil was produced according to the method of example 1, except that 20g of the catalyst Cat-1 and 180g of the catalyst Cat-2 were charged in the first reactor and the second reactor of the high-pressure hydrogenation reaction apparatus, respectively.

Example 7

A white oil was produced according to the method of example 1, except that 180g of the catalyst Cat-1 and 20g of the catalyst Cat-2 were charged in the first reactor and the second reactor of the high-pressure hydrogenation reaction apparatus, respectively.

As can be seen from the data in Table 4, the process for producing white oil according to the present invention can achieve better aromatics saturation effect.

The preferred embodiments of the present invention have been described in detail, however, the present invention 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 invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the content of the present invention as long as it does not depart from the gist of the present invention.

TABLE 1

TABLE 2

Analysis item	Analyzing data
		Density/(g cm) at 20 DEG C^-3)	0.8795
Pour point/. degree.C	-24
		Distillation range/. degree.C
IBP/(5％/10％/70％/90％)	184/272/328/451/512
		S mass fraction/(μ g/g)	9.2
N mass fraction/(μ g/g)	4.8
		Bromine number/(gBr. 100g)^-1)	0.01
Mass fraction of aromatic hydrocarbons/%	9.3

TABLE 3

Reaction conditions	Condition
		Pressure, MPa	12.0
Volumetric space velocity h^-1	10
		Reaction temperature of	220
Hydrogen to oil ratio, v/v	500

TABLE 4

Claims

1. A combined catalyst, which is characterized in that the combined catalyst comprises a first catalyst and a second catalyst, wherein the first catalyst contains a ten-membered ring molecular sieve M1, the second catalyst contains a twelve-membered ring molecular sieve M2, the first catalyst and the second catalyst respectively and independently contain an active metal component, and the first catalyst and the second catalyst are respectively loaded in different reactors;

wherein the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 has the following characteristics: the molar ratio of silicon oxide to aluminum oxide is 120-300; contains a mesoporous structure and has a closed hysteresis loop at a low-temperature nitrogen adsorption-desorption curve P/P0=0.4-0.99, and the starting position of the closed hysteresis loop is at P/P0= 0.4-0.7;

the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 was prepared according to the following steps:

(1) filtering the mother liquor after the molecular sieve precursor is crystallized to form a filter cake with the dry basis content of 5-30 wt%; "dry basis content" is defined as: the mass of the material after roasting for 4 hours at 600 ℃ accounts for the mass of the material before roasting;

(2) directly roasting the filter cake without drying to obtain a molecular sieve precursor;

(3) subjecting the molecular sieve precursor to a hydrothermal treatment; the medium of the hydrothermal treatment is an acidic aqueous solution;

(4) and filtering, washing and drying the hydrothermal treatment product.

2. The combination catalyst as claimed in claim 1, wherein the molecular sieve has a silica/alumina molar ratio of 150-200 in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2.

3. The combined catalyst according to claim 1, wherein in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2, the mesoporous area in the molecular sieve is 50M²/g-250m²The proportion of the mesoporous area in the specific surface area is 20-70 percent.

4. The combined catalyst according to claim 3, wherein the proportion of mesoporous area in the molecular sieve in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 is 25% to 65% of the specific surface area.

5. A combined catalyst according to claim 1 wherein the closed hysteresis loop in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2 has a starting position at P/P0= 0.4-0.6.

6. The combination catalyst of claim 1 wherein the amount of penta-coordinated aluminum in the molecular sieve precursor ranges from 4 to 30 wt.% on an oxide basis and based on the total alumina amount of the molecular sieve in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2.

7. A combined catalyst according to claim 6 wherein the amount of penta-coordinated aluminium in the molecular sieve precursor is in the range 10 to 30 wt% calculated as oxide and based on total alumina amount of molecular sieve in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2.

8. A combined catalyst as claimed in claim 1 wherein in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2, the amount of penta-coordinated aluminum in the finished molecular sieve is 3% by weight or less, calculated as oxide and based on the total alumina amount of the molecular sieve.

9. A combined catalyst according to claim 8 wherein the amount of penta-coordinated aluminium in the finished molecular sieve is 1% by weight or less calculated as oxide and based on the total alumina content of the molecular sieve in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2.

10. The combination catalyst of claim 9, wherein no penta-coordinated aluminum is present in the finished molecular sieve in the ten-membered ring molecular sieve M1 and/or the twelve-membered ring molecular sieve M2.

11. The combined catalyst according to claim 1, wherein in step (1), the filter cake formed by the filtration has a dry content of 6-15 wt%.

12. The combined catalyst according to claim 1, wherein, in the step (2), the calcination temperature is 400-600 ℃.

13. The combined catalyst according to claim 12, wherein, in the step (2), the temperature of the calcination is 450-550 ℃.

14. The combined catalyst according to claim 1, wherein in step (3), the acidic aqueous solution contains an inorganic acid and/or an organic acid, and the content of the inorganic acid and/or the organic acid is 0.1M to 5M.

15. The combined catalyst according to claim 14, wherein in step (3), the content of the inorganic acid and/or the organic acid is 0.2M to 2M.

16. The combination catalyst of claim 14, wherein the acidic aqueous solution comprises at least one of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, citric acid, acetic acid, maleic acid, oxalic acid, nitrilotriacetic acid, 1, 2-cyclohexanediaminetetraacetic acid, tartaric acid, and malic acid.

17. The combined catalyst according to claim 1, wherein in step (3), the liquid-solid volume ratio of the hydrothermal treatment is 5-200; the temperature of the hydrothermal treatment is 100-300 ℃; the time of the hydrothermal treatment is 0.5 to 24 hours.

18. The combined catalyst according to claim 17, wherein in step (3), the liquid-solid volume ratio of the hydrothermal treatment is 20-100; the temperature of the hydrothermal treatment is 100-200 ℃; the time of the hydrothermal treatment is 1 hour to 12 hours.

19. The combined catalyst of claim 18, wherein the hydrothermal treatment is for a time of 1 hour to 4 hours.

20. The combined catalyst according to claim 17, wherein the hydrothermal treatment is carried out in a closed vessel and the pressure of the hydrothermal treatment is the autogenous pressure of the closed vessel under hydrothermal conditions.

21. The combined catalyst according to claim 1, wherein in step (4), the washing process is water washing with deionized water, and the water washing is completed until the pH value of the filtrate is 6-8.

22. The combination catalyst of claim 21, wherein the washing is performed with deionized water until the filtrate pH is 6-7.

23. The combined catalyst of claim 1, wherein the reactor packed with the first catalyst is located upstream or downstream of the reactor packed with the second catalyst in terms of the reactant stream direction.

24. The combination catalyst of claim 1, wherein the ten-membered ring molecular sieve M1 is selected from one or more of ZSM-22, ZSM-48, ZSM-5 and SSZ-32, and the twelve-membered ring molecular sieve M2 is selected from one or more of ZSM-12 molecular sieve, beta molecular sieve and Y molecular sieve.

25. The combined catalyst of claim 24, wherein the Y molecular sieve is a USY molecular sieve and/or LaY molecular sieve.

26. The combination catalyst of claim 1, wherein the difference between the silica/alumina mole ratio of the ten-membered ring molecular sieve M1 and the silica/alumina mole ratio of the twelve-membered ring molecular sieve M2 is from 5 to 60.

27. The combination catalyst of claim 26, wherein the difference between the silica/alumina mole ratio of the ten-membered ring molecular sieve M1 and the silica/alumina mole ratio of the twelve-membered ring molecular sieve M2 is 20-40.

28. The combined catalyst of claim 1, wherein the loading weight ratio of the first catalyst to the second catalyst is 1: (0.1-1.0);

the active metal component is Pt;

the first catalyst also comprises a heat-resistant inorganic oxide, and the content of the ten-membered ring molecular sieve M1 is 20-80 wt% and the content of the active metal component is 0.1-5 wt% based on the weight of the first catalyst;

the second catalyst also comprises a heat-resistant inorganic oxide, and the content of the twelve-membered ring molecular sieve M2 is 20-80 wt% and the content of the active metal component is 0.1-5 wt% based on the weight of the second catalyst.

29. The combined catalyst of claim 28,

based on the weight of the first catalyst, the content of the ten-membered ring molecular sieve M1 is 25-55 wt%, and the content of the active metal component is 0.2-3 wt%;

the content of the twelve-membered ring molecular sieve M2 is 25 to 55 wt% and the content of the active metal component is 0.2 to 3 wt% based on the weight of the second catalyst.

30. The combined catalyst of claim 29, wherein,

the content of the active metal component is 0.4-1 wt% based on the weight of the first catalyst;

the active metal component is present in an amount of 0.4 to 1 wt% based on the weight of the second catalyst.

31. A process for the production of a white oil, which process comprises injecting a white oil feedstock into a reaction unit for hydroprocessing, wherein the reaction unit is packed with a catalyst comprising a combined catalyst according to any one of claims 1 to 30; in the combined catalyst, the first catalyst and the second catalyst are respectively filled in different reactors.

32. The process as claimed in claim 31, wherein the distillation range of the white oil feedstock is 100-600 ℃;

the hydrotreating conditions for the different reactors independently comprise: the temperature is 100-500 ℃; the pressure is 1-30 MPa; the volume space velocity is 0.1-5h^-1(ii) a The volume ratio of hydrogen to oil is 50-3000.

33. The method of claim 32, wherein the hydrotreating conditions for different reactors each independently comprise: the temperature is 200-400 ℃; the pressure is 2-20 MPa; the volume space velocity is 0.1-3h^-1(ii) a The volume ratio of hydrogen to oil is 300-3000.

34. The method of claim 33, wherein the hydrotreating conditions for different reactors each independently comprise: the temperature is 220 ℃ and 300 ℃; the pressure is 5-20 MPa; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of the hydrogen to the oil is 400-600.