Multi-stage hydroisomerization catalyst combination method and multi-stage hydroisomerization method

Abstract

The present invention relates to the field of catalysts, and discloses a multi-stage hydroisomerization catalyst combination method and a multi-stage hydroisomerization method. The combination method comprises a first hydroisomerization catalyst and a second hydroisomerization catalyst sequentially loaded along a logistics direction, wherein the first hydroisomerization catalyst is loaded in a first hydrogenation reactor, and the second hydroisomerization catalyst is loaded in a second hydrogenation reactor, wherein the first hydroisomerization catalyst and / or the second hydroisomerization catalyst independently comprise a ZSM-48 molecular sieve, wherein the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve is not less than 40, and the specific surface area of ​​the ZSM-48 molecular sieve is not less than 200 m 2 / g, the crystals of the ZSM-48 molecular sieve are ellipsoidal, the major diameter does not exceed 700 nm and the ratio of major diameter to minor diameter is 1-3: 1. The multi-stage hydroisomerization catalyst combination method provided by the present invention helps to improve the efficiency of the catalytic reaction. When the method of the present invention is used to process oil products, the product pour point is lower and the product yield is higher.

Description

Technical Field

[0001] The invention relates to the field of catalysts, and in particular to a multi-stage hydroisomerization catalyst combination method and a multi-stage hydroisomerization method. Background Art

[0002] ZSM-48 molecular sieve is a new type of high-silicon molecular sieve developed in the 1980s. It has a two-dimensional ten-membered ring pore structure and belongs to the orthorhombic crystal system. The pores are connected by 5-membered rings, and the pore diameter is about 0.6nm. It is characterized by a high silicon-aluminum molar ratio and tubular linear pores, which can accommodate organic molecules with a smaller kinetic radius than benzene. Theoretically, ZSM-48 molecular sieve has a smaller pore "self-restraint effect", and the pore size is suitable for the shape-selective isomerization of chain alkanes. At present, ZSM-48 molecular sieve can be synthesized using a variety of organic templates. For example, N-methylpyridine (US4585747), ethylenediamine (US5961951), alkylamine and tetramethylammonium (CN101330975A), N,N-diethylhexamethyleneimine quaternary ammonium (CN102040231A), hexamethyldiamine chloride (US7482300 / US7625478), 1,6-hexanediamine or 1,8-octanediamine (US6923949A), etc.

[0003] The lubricating base oil produced by the hydroisomerization dewaxing method has a higher paraffin content and a lower S and N content, and has higher antioxidant stability, lower volatility, higher viscosity index (VI) and excellent low-temperature flow properties. Compared with traditional solvent dewaxing, hydrocracking and other methods, it shows good performance and economic and environmental advantages. The core of the hydroisomerization dewaxing technology is mainly composed of isomerization dewaxing catalysts. Isomerization dewaxing catalysts are bifunctional catalysts, which usually load precious metals Pt and / or Pd onto molecular sieves with special pore structures. However, in the existing technology, the yield of hydroisomerization dewaxing is still low, and the pour point of the product is high. Therefore, it is crucial to use special catalytic materials and matching processes to improve the efficiency of lubricating oil production. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of poor isomerization selectivity and low product yield in the prior art when processing heavy waxy raw materials such as Fischer-Tropsch wax. A multi-stage hydrogenation isomerization catalyst combination method and a multi-stage hydrogenation isomerization method are provided, which can adjust and control the isomerization reaction in stages through a specific catalyst combination.

[0005] In order to achieve the above-mentioned object, the present invention provides a multi-stage hydroisomerization catalyst combination method, which comprises a first hydroisomerization catalyst and a second hydroisomerization catalyst sequentially loaded along the logistics direction, wherein the first hydroisomerization catalyst is loaded in a first hydrogenation reactor, and the second hydroisomerization catalyst is loaded in a second hydrogenation reactor, wherein the first hydroisomerization catalyst and / or the second hydroisomerization catalyst independently comprise ZSM-48 molecular sieve, wherein the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve is not less than 40, and the specific surface area of ​​the ZSM-48 molecular sieve is not less than 200 m 2 / g, the crystal grains of the ZSM-48 molecular sieve are ellipsoidal, the major diameter does not exceed 700nm and the ratio of major diameter to minor diameter is 1-3:1.

[0006] The second aspect of the present invention provides a multi-stage hydroisomerization method, which comprises: under hydroisomerization conditions, injecting a feedstock to be hydroisomerized into a hydroisomerization device for reaction, wherein the catalyst in the hydroisomerization device is loaded according to the combination method described in the first aspect.

[0007] The multi-stage hydroisomerization catalyst combination method provided by the present invention helps to improve the efficiency of the catalytic reaction. When the method of the present invention is used to process oil products, the product pour point is lower and the product yield is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is the X-ray diffraction pattern of the seed crystal A1 obtained in Preparation Example 1-1 after calcination;

[0009] Figure 2 is the X-ray diffraction pattern of the seed crystal A3 obtained in Preparation Example 1-3 after calcination;

[0010] Figure 3 is a SEM image of the ZSM-48 molecular sieve in Preparation Example 2-1;

[0011] Figure 4 It is a schematic diagram of the Fischer-Tropsch wax hydrogenation reaction unit. DETAILED DESCRIPTION

[0012] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0013] The first aspect of the present invention provides a multi-stage hydroisomerization catalyst combination method, which comprises a first hydroisomerization catalyst and a second hydroisomerization catalyst sequentially loaded along a logistics direction, wherein the first hydroisomerization catalyst is loaded in a first hydrogenation reactor, and the second hydroisomerization catalyst is loaded in a second hydrogenation reactor, wherein the first hydroisomerization catalyst and / or the second hydroisomerization catalyst each independently comprises a ZSM-48 molecular sieve, wherein the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve is not less than 40, and the specific surface area of ​​the ZSM-48 molecular sieve is not less than 200 m 2 / g, the crystal grains of the ZSM-48 molecular sieve are ellipsoidal, the major diameter does not exceed 700nm and the ratio of major diameter to minor diameter is 1-3:1.

[0014] In the present invention, it can be understood by those skilled in the art that the first hydroisomerization catalyst and the second hydroisomerization catalyst may both contain ZSM-48 molecular sieve, or the first hydroisomerization catalyst may contain ZSM-48 molecular sieve while the second hydroisomerization catalyst may not contain ZSM-48 molecular sieve, or the first hydroisomerization catalyst may not contain ZSM-48 molecular sieve while the second hydroisomerization catalyst may contain ZSM-48 molecular sieve. The multi-stage hydroisomerization catalyst combination method provided by the present invention helps to improve the efficiency of the catalytic reaction.

[0015] According to a preferred embodiment of the present invention, the specific surface area of ​​the ZSM-48 molecular sieve is 200-280m 2 / g.

[0016] According to a preferred embodiment of the present invention, the ratio of the length to the short diameter of the ZSM-48 molecular sieve is 1-2:1.

[0017] According to a preferred embodiment of the present invention, the pore volume of the ZSM-48 molecular sieve is 0.20-0.30 ml / g.

[0018] According to a preferred embodiment of the present invention, the crystal size of the ZSM-48 molecular sieve is 300-700 nm, preferably 400-600 nm.

[0019] According to a preferred embodiment of the present invention, the method for preparing the ZSM-48 molecular sieve comprises the following steps:

[0020] (1) providing a mixture containing a silicon source, an alkali source, an aluminum source, a template, water, a molecular sieve mother liquor, and a seed crystal;

[0021] (2) subjecting the mixture to a crystallization reaction; the conditions of the crystallization reaction include: reacting at 20° C.-50° C. for 1-24 h, reacting at 50° C.-80° C. for 0.5-36 h, and then reacting at 80° C.-180° C. for 0.5-72 h;

[0022] (3) The mixture obtained by the crystallization reaction in step (2) is subjected to solid-liquid separation to obtain ZSM-48 molecular sieve and molecular sieve mother liquor, and the molecular sieve mother liquor is returned to step (1);

[0023] The method further comprises an optional step (4), which comprises: acidifying and precipitating the molecular sieve mother liquor, and then performing solid-liquid separation, and returning the obtained filtrate to step (1);

[0024] The mass percentage of the added seed crystals in step (1) is not less than 10% of the mass percentage of the silicon source, where the silicon source is calculated as SiO2.

[0025] According to the present invention, the molecular sieve mother liquor is recycled and seed crystals are introduced to obtain smaller crystal nuclei. In the present invention, the progress and temperature of the crystallization reaction are strictly controlled through three stages of crystallization processes at different temperatures. Compared with the prior art, the crystallization reaction process is set at a low temperature, which helps to control the growth of the crystal nuclei.

[0026] In the present invention, it is understood by those skilled in the art that the molecular sieve mother liquor can be obtained by selecting the above step (3), or by steps (3) and (4). When the molecular sieve mother liquor is obtained by steps (3) and (4), it is understood by those skilled in the art that the filtrate in step (4) provides at least part of the molecular sieve mother liquor in step (1).

[0027] According to the present invention, the amount of seed crystals used in step (1) is relatively large. According to a preferred embodiment of the present invention, the mass percentage of the seed crystals added in step (1) is 10-30% of the mass percentage of the silicon source, and more preferably 20-30%. In the above preferred case, it is conducive to forming more crystal nuclei in the solution, and the prepared molecular sieve has the characteristics of small grains.

[0028] According to the present invention, preferably, in the mixture of step (1), the amount of water is greater than the amount of molecular sieve mother liquor, and further preferably, the mass percentage of the molecular sieve mother liquor added in step (1) to the total mass percentage of the molecular sieve mother liquor and water in step (1) is no more than 50%, more preferably 10-30%. The above preferred embodiment is helpful to increase the specific surface area of ​​the molecular sieve.

[0029] According to a preferred embodiment of the present invention, the water may be deionized water.

[0030] In the present invention, the ratio of each raw material in the reactants has a certain influence on the silicon-aluminum ratio and the final performance of the molecular sieve. According to a preferred embodiment of the present invention, specifically, the composition of each component in the mixture in step (1) calculated by molar amount satisfies the following relationship:

[0031] R / SiO2=0.01-0.5, preferably 0.01-0.1;

[0032] M + / SiO2=0.01-0.50, preferably 0.1-0.3;

[0033] Al2O3 / SiO2=0-0.02, preferably 0.01-0.015;

[0034] H2O / SiO2=5-50, preferably 10-30;

[0035] Wherein, SiO2 refers to SiO2 in the silicon source, R represents the template, and M + Indicates alkaline source.

[0036] There is no particular limitation on the types of silicon source, alkali source and aluminum source in step (1) of the present invention, and the above raw materials are conventionally selected in the art. Preferably, they can be mixed into a uniform colloid by corresponding means, for example, by stirring.

[0037] According to a preferred embodiment of the present invention, the silicon source is selected from at least one of silica sol, water glass, fumed silica, white carbon black and tetraethyl orthosilicate; more preferably, it is silica sol.

[0038] According to a preferred embodiment of the present invention, the alkali source is selected from alkaline metal salts, preferably at least one of calcium hydroxide, potassium hydroxide and sodium hydroxide; more preferably sodium hydroxide.

[0039] According to a preferred embodiment of the present invention, the aluminum source is selected from at least one of pseudo-boehmite, aluminum sulfate, aluminum isopropoxide and sodium aluminate; more preferably, sodium aluminate.

[0040] According to a preferred embodiment of the present invention, the template is selected from at least one of ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-hexanediamine, hexamethylammonium chloride, hexamethylammonium bromide and hexamethylammonium hydroxide, and is further preferably at least one of hexamethylammonium chloride, hexamethylammonium bromide and hexamethylammonium hydroxide.

[0041] According to a preferred embodiment of the present invention, the conditions of the crystallization reaction in step (2) include: reacting at 20°C-50°C for 6-24h, reacting at 50°C-80°C for 12-36h, and then reacting at 80°C-180°C for 48-72h. Wherein, 20°C-50°C means 20°C≤t1<50°C, 50°C-80°C means 50°C≤t2≤80°C, and 80°C-180°C means 80°C<t3≤180°C. Under the above preferred embodiment, the formation of small-grained ZSM-48 is favorable.

[0042] According to a preferred embodiment of the present invention, in step (4), the acidification precipitation comprises: adding acid to the molecular sieve mother liquor to adjust the pH value to 3-7, preferably 5-6.5.

[0043] Preferably, the acidification deposition time is 0.5-4h.

[0044] Under the above preferred implementation mode, it is beneficial to prepare molecular sieves with high specific surface area.

[0045] In the present invention, the selection range of the type of acid described in step (4) is relatively wide, as long as the pH can be adjusted to the above range. Preferably, the acid can be at least one of hydrochloric acid, nitric acid, ammonium chloride, ammonium nitrate, and ammonium oxalate.

[0046] According to a preferred embodiment of the present invention, the seed crystal is a ZSM-48 molecular sieve seed crystal, and the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve seed crystal is not less than 40, preferably 45 to 500. The silicon-aluminum ratio in the ZSM-48 molecular sieve seed crystal mainly depends on the feeding and preparation method of the silicon source and aluminum source in the raw material.

[0047] According to a preferred embodiment of the present invention, the method for preparing the seed crystal comprises contacting a reaction mixture under crystallization conditions, wherein the reaction mixture comprises a silicon source, an alkali source, an aluminum source, a template and water.

[0048] According to a preferred embodiment of the present invention, the preparation method of the seed mainly includes three steps of crystallization, and the temperature of each crystallization is higher than the previous crystallization temperature. Specifically, the first step crystallization temperature t1 satisfies 15℃≤t1<50℃, preferably carried out at room temperature, more preferably 20℃≤t1≤45℃, and the first step crystallization time is 5-24h, preferably 6-15h; the second step crystallization temperature t2 satisfies 50℃≤t2<100℃, preferably 60℃≤t2≤80℃, and the second step crystallization time is 0.5-36h, preferably 5-30h; the third step crystallization temperature t3 satisfies 100℃≤t3≤200℃, preferably 120℃≤t3≤190℃, and the third step crystallization time is 10-96h, preferably 20-80h.

[0049] According to a preferred embodiment of the present invention, the selection range of the silicon source, alkali source, aluminum source and template agent in the seed crystal preparation process is the same as that described above, and no further description is given here; the types of the selected silicon source, alkali source, aluminum source and template agent can be the same as or different from the types of the silicon source, alkali source, aluminum source and template agent described in the molecular sieve preparation process. Specifically, the content of each component in the reaction mixture satisfies the following relationship:

[0050] R / SiO2=0.01-0.50, more preferably 0.01-0.3;

[0051] H2O / SiO2=5-50, more preferably 5-20;

[0052] M + / SiO2=0.01-0.50, more preferably 0.01-0.15;

[0053] Al2O3 / SiO2=0-0.02; more preferably 0.01-0.017;

[0054] Wherein, R represents a template, and M+ represents an alkali source.

[0055] According to a preferred embodiment of the present invention, the process of preparing the seed crystals further includes performing solid-liquid separation on the crystallization product to obtain the seed crystals.

[0056] In the X-ray diffraction pattern of the seed crystal after calcination at 400-700°C for 1-8h, the peak height of the diffraction peak with a 2θ angle of 21°-22° is taken as the reference value, and the peak height of the diffraction peak with a 2θ angle of 7°-8° is not less than 70% of the reference value.

[0057] The seed crystals obtained by the above preferred embodiment are used for the preparation of the above molecular sieve, which is conducive to obtaining a ZSM-48 molecular sieve with a high specific surface area.

[0058] In order to obtain the molecular sieve raw powder of the present invention, the reaction system after the above crystallization can be further subjected to solid-liquid separation and drying and other operations. The methods and conditions for solid-liquid separation and drying are conventional operations in the art and are not repeated here. For example, the reaction product can be filtered and then dried at 120° C. for 6 hours to obtain the molecular sieve.

[0059] According to a preferred embodiment of the present invention, the second hydroisomerization catalyst includes the ZSM-48 molecular sieve. It can be understood by those skilled in the art that when the second hydroisomerization catalyst includes the ZSM-48 molecular sieve, the first hydroisomerization catalyst may contain or not contain the above molecular sieve. Preferably, the second hydroisomerization catalyst includes the ZSM-48 molecular sieve, while the first hydroisomerization catalyst does not contain the ZSM-48 molecular sieve. In the above preferred case, it is beneficial to improve the yield of the isomerized product.

[0060] According to a preferred embodiment of the present invention, the first hydroisomerization catalyst includes other types of one-dimensional ten-membered ring channel molecular sieves, preferably, the other types of one-dimensional ten-membered ring channel molecular sieves are selected from at least one of ZSM-22, SAPO-11, ZSM-23, and SSZ-32, more preferably ZSM-22. The above preferred embodiment is used to help match the molecular reaction process and thus improve the product yield.

[0061] According to a preferred embodiment of the present invention, the first hydroisomerization catalyst and the second hydroisomerization catalyst each independently contain an active metal and optionally a binder.

[0062] According to a preferred embodiment of the present invention, the active metal is selected from at least one of Pt, Pd, Ni and Co.

[0063] In the present invention, the selection range of the binder type is relatively wide. Preferably, the binder is selected from at least one of alumina, pseudo-boehmite, amorphous silica-alumina, silicon oxide and titanium oxide.

[0064] According to a preferred embodiment of the present invention, based on the total amount of the first hydroisomerization catalyst, the content of other types of one-dimensional ten-membered ring channel molecular sieves is 20-80% by weight, preferably 30-70%; calculated as oxide, the content of the active metal is 0.1-2% by weight, preferably 0.3-0.6%; the content of the binder is 20-80% by weight, preferably 30-70%.

[0065] According to a preferred embodiment of the present invention, based on the total amount of the second hydroisomerization catalyst, the content of ZSM-48 molecular sieve is 20-80% by weight, preferably 40-70%; the content of the active metal is 0.1-2% by weight, preferably 0.3-0.6% in terms of oxide; the content of the binder is 20-80% by weight, preferably 40-70%. The use of the above preferred molecular sieve content is conducive to controlling the catalyst activity.

[0066] In the present invention, the first hydroisomerization catalyst and the second hydroisomerization catalyst can be prepared by conventional methods in the art as long as they meet the above component requirements.

[0067] The method provided by the present invention has a wide range of selection for the volume loading ratio of the first hydroisomerization catalyst and the second hydroisomerization catalyst. Preferably, the volume loading ratio of the first hydroisomerization catalyst and the second hydroisomerization catalyst is 0.5-2:1.

[0068] The second aspect of the present invention provides a multi-stage hydroisomerization method, which comprises: under hydroisomerization conditions, injecting a feedstock to be hydroisomerized into a hydroisomerization device for reaction, wherein the catalyst in the hydroisomerization device is loaded according to the combination method described in the first aspect.

[0069] According to the present invention, the hydroisomerization device comprises: connecting a first hydroisomerization reactor and a second hydroisomerization reactor in series, loading a first hydroisomerization catalyst in the first hydroisomerization reactor, loading a second hydroisomerization catalyst in the second hydroisomerization reactor, and the raw material flows through the first hydroisomerization reactor and then enters the second hydroisomerization reactor for reaction.

[0070] According to a preferred embodiment of the present invention, the raw material to be hydroisomerized is selected from at least one of cracked tail oil, bio-jet fuel production raw material, C5C6 isomerization raw material, and Fischer-Tropsch synthesis wax.

[0071] Preferably, the hydroisomerization conditions include: temperature of 200-500°C, preferably 250-400°C; pressure of 1-30MPa, preferably 2-20MPa; volume space velocity of 0.1-5h -1 , preferably 0.1-3h -1 ; The volume ratio of hydrogen to oil is 50-3000, preferably 300-3000.

[0072] According to a preferred embodiment of the present invention, the hydrogenation isomerization conditions in the first hydrogenation reactor and the second hydrogenation reactor can be adjusted respectively according to the loaded catalyst. Preferably, the pressure in the first hydrogenation reactor is greater than the pressure in the second hydrogenation reactor; further preferably, the pressure in the first hydrogenation reactor is ≥5.0MPa, and the pressure in the second hydrogenation reactor is <5.0MPa.

[0073] According to a preferred embodiment of the present invention, the temperature in the first hydrogenation reactor is different from that in the second hydrogenation reactor. Preferably, the temperature difference between the first hydrogenation reactor and the second hydrogenation reactor is ≥10°C. It can be understood by those skilled in the art that, according to the different catalysts loaded in the reactors, the temperature in the first hydrogenation reactor can be greater than the temperature in the second hydrogenation reactor, or the temperature in the second hydrogenation reactor can be greater than the temperature in the first hydrogenation reactor, as long as the temperature difference between the two hydrogenation reactors meets the above range. The above preferred embodiment is adopted to help improve the product yield.

[0074] The present invention will be described in detail below through examples.

[0075] In the following examples and comparative examples, a Bruker D5005 diffractometer was used to perform XRD characterization on the samples, Cu Kα rays (λ=0.154 nm), tube voltage 40 kV, tube current 30 mA, scanning range 5°-35°, step 0.013°, 1 step per second. The S-4800 scanning electron microscope (SEM) produced by Hitachi was used to characterize the morphology and size of the samples, with an acceleration voltage of 20 kV. The ESCA Lab250 X-ray photoelectron spectrometer produced by Thermo Scientific was used for XPS characterization, with the excitation source being monochromatic Al Kα X-rays, power 300 W, and the basic vacuum degree of the analysis chamber being about 3×10 -7 Pa.

[0076] The composition of the samples was determined using a 3271E X-ray fluorescence spectrometer (XRF) produced by Rigaku Corporation. The sample preparation method was the tablet pressing method, and the measurement conditions were an end-window rhodium target, a tube voltage of 50 kV, and a tube current of 50 mA.

[0077] The dry basis of molecular sieve and pseudo-boehmite in the examples refers to the weight after calcination at 600° C. for 2 h.

[0078] The pore structure parameters of the product, such as specific surface area and pore volume, were measured using the BET method.

[0079] The method for measuring element content in the product is DZ / T0279.1-2016.

[0080] The isomerization catalyst RIW-1 used in the examples is a commercial product from Changling Catalyst Factory, wherein the molecular sieve is SAPO-11.

[0081] The following preparation examples are used to illustrate the preparation of seed crystals.

[0082] Preparation Example 1-1

[0083] Aluminum sulfate, hexamethyldiamine hydroxide (HMOH), sodium hydroxide and deionized water were mixed in a certain proportion, stirred for 30 minutes and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMOH):n(Na + ):n(H2O):n(SiO2)=0.01:0.03:0.3:8:1, the mixture was transferred into a crystallization kettle, and crystallized for 6 hours at room temperature with stirring at a speed of 400rpm; then crystallized for 24 hours at 80℃, and then heated to 180℃ for crystallization for 48 hours. After the crystallization, the solid product was filtered and dried at 120℃ for 6 hours, and the obtained product was seed A1. After the crystallization, the product obtained by filtering and drying was seed A1. After the seed A1 was calcined at 600℃ for 4 hours, the XRD diffraction peak was seen Figure 1 .

[0084] Preparation Example 1-2

[0085] Sodium aluminate, hexamethyldiamine chloride (HMCl), sodium hydroxide and deionized water were mixed in a certain proportion, stirred for 30 minutes and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.004:0.03:0.3:21:1, the mixture was transferred into a crystallization kettle, and crystallized for 12h under stirring at room temperature, with a stirring speed of 350rpm; crystallized for 12h at 60℃ and for 48h at 160℃. After the crystallization, the product was filtered and dried at 120℃ for 6h. The product obtained by filtering and drying after the crystallization was seed A2.

[0086] Preparation Example 1-3

[0087] Sodium aluminate, hexamethyldiamine chloride (HMCl), sodium hydroxide and deionized water were mixed in a certain proportion, stirred for 30 minutes and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.004:0.03:0.3:21:1, the mixture was transferred into a crystallization kettle, and crystallized for 12h under stirring at room temperature, with a stirring speed of 350rpm; crystallized for 60h at 170℃, and the product obtained by filtering and drying after the crystallization was seed A3. After calcining seed A3 at 600℃ for 4h, XRD showed Figure 2 .

[0088] The following preparation example is used to illustrate the preparation of ZSM-48 molecular sieve.

[0089] Preparation Example 2-1

[0090] (1) Aluminum sulfate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.01:0.03:0.3:10:1. The added mass percentage of the molecular sieve mother liquid accounts for 30% of the total mass percentage of the molecular sieve mother liquid and water in step (1), and 25% of the mass of SiO2 is added as ZSM-48 seed crystal A1;

[0091] (2) The mixture was transferred into a crystallization reactor, stirred at room temperature for 6 h, crystallized at 80 °C for 24 h, and crystallized at 170 °C for 48 h;

[0092] (3) After the crystallization is completed, the ZSM-48 molecular sieve and the molecular sieve mother liquor are obtained by filtering, and the molecular sieve mother liquor is returned to step (1);

[0093] After drying at 120°C for 6 hours, the product ZSM-48 molecular sieve was obtained and recorded as Z-1. The XRF analysis results of the silicon-aluminum ratio and the specific surface area of ​​the prepared ZSM-48 molecular sieve are shown in Table 1, and the scanning electron microscope image is shown in Figure 3 Its morphology is ellipsoidal, the particle major diameter is 300-700nm, and the ratio of major diameter to minor diameter is about 1.1-1.4:1.

[0094] Preparation Example 2-2

[0095] (1) Sodium aluminate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.004:0.03:0.3:20:1, the mass percentage of the added molecular sieve mother liquor to the total mass percentage of the molecular sieve mother liquor and water in step (1) is 20%, and 15% of the mass of SiO2 ZSM-48 seed crystals A2 are added;

[0096] (2) transferring the above mixture into a crystallization kettle, crystallizing at 40°C for 12 h, at 80°C for 10 h, and at 170°C for 48 h;

[0097] (3) After the crystallization is completed, the ZSM-48 molecular sieve and the molecular sieve mother liquor are obtained by filtering, and the molecular sieve mother liquor is returned to step (1);

[0098] After drying at 120°C for 6 hours, the product ZSM-48 molecular sieve was obtained and recorded as Z-2. The XRF analysis results and specific surface area data of the prepared ZSM-48 molecular sieve are shown in Table 1. Its morphology is ellipsoidal, the particle major diameter is 300-600nm, and the ratio of major diameter to minor diameter is about 1.1-1.4:1.

[0099] Preparation Example 2-3

[0100] (1) Aluminum sulfate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing an acidified molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.01:0.03:0.3:10:1, the added mass percentage of the molecular sieve mother liquor accounts for 30% of the total mass percentage of the molecular sieve mother liquor and water in step (1), and 25% of the mass of SiO2 ZSM-48 seed crystals A1 are added;

[0101] (2) The mixture was transferred into a crystallization reactor, stirred at room temperature for 6 h, crystallized at 80 °C for 24 h, and crystallized at 170 °C for 48 h;

[0102] (3) After the crystallization is completed, the ZSM-48 molecular sieve and the molecular sieve mother liquor are filtered to obtain, and the molecular sieve mother liquor is acidified and precipitated. The acidification process is to adjust the pH value of the mother liquor to 6.2 with ammonium chloride, stand for 2 hours, and return the filtrate obtained by filtration to step (1);

[0103] After drying at 120°C for 6 hours, the product ZSM-48 molecular sieve was obtained and recorded as Z-3. The XRF analysis results and specific surface area data of the prepared ZSM-48 molecular sieve are shown in Table 1. Its morphology is ellipsoidal, the particle major diameter is 300-600nm, and the ratio of major diameter to minor diameter is about 1.1-1.5:1.

[0104] Preparation Example 2-4

[0105] (1) Sodium aluminate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.004:0.03:0.3:20:1, the mass percentage of the added molecular sieve mother liquor to the total mass percentage of the molecular sieve mother liquor and water in step (1) is 20%, and 15% of the mass of SiO2 ZSM-48 seed crystals A2 are added;

[0106] (2) transferring the above mixture into a crystallization kettle, crystallizing at 40°C for 12 h, at 80°C for 10 h, and at 170°C for 48 h;

[0107] (3) After the crystallization is completed, the ZSM-48 molecular sieve and the molecular sieve mother liquor are filtered to obtain, and the molecular sieve mother liquor is acidified and precipitated. The acidification process is to adjust the pH value of the mother liquor to 5.6 with ammonium chloride, stand for 3 hours, and return the filtrate obtained by filtration to step (1);

[0108] After drying at 120°C for 6 hours, the product ZSM-48 molecular sieve was obtained and recorded as Z-4. The XRF analysis results and specific surface area data of the prepared ZSM-48 molecular sieve are shown in Table 1. Its morphology is ellipsoidal, the particle major diameter is 400-700nm, and the ratio of major diameter to minor diameter is about 1.1-1.4:1.

[0109] Comparative Preparation Example 1

[0110] (1) Aluminum sulfate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.01:0.03:0.3:10:1. Add 25% of the mass of SiO2 in ZSM-48 seed crystal A3. The mass percentage of the added molecular sieve mother liquid to the total mass percentage of the molecular sieve mother liquid and water in step (1) is 20%;

[0111] (2) The mixture was transferred into a crystallization reactor, stirred at room temperature for 6 h, crystallized at 80 °C for 24 h, and crystallized at 170 °C for 48 h;

[0112] (3) After the crystallization is completed, the ZSM-48 molecular sieve DZ-1 is obtained by filtering and drying. The XRF analysis results and specific surface area data of the obtained ZSM-48 molecular sieve are shown in Table 1. Its morphology is rod-shaped, and the ratio of the length to the short diameter is about 7:1.

[0113] Comparative Preparation Example 2

[0114] (1) Aluminum sulfate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.01:0.03:0.3:30:1. Add 25% of the mass of SiO2 ZSM-48 seed crystal A3;

[0115] (2) The mixture was transferred into a crystallization reactor, stirred at room temperature for 6 h, crystallized at 80 °C for 24 h, and crystallized at 170 °C for 48 h;

[0116] (3) After the crystallization is completed, the ZSM-48 molecular sieve DZ-2 is obtained by filtering and drying. The XRF analysis results and specific surface area data of the obtained ZSM-48 molecular sieve are shown in Table 1. Its morphology is rod-shaped, and the ratio of the length to the short diameter is about 5:1.

[0117] Comparative Preparation Example 3

[0118] (1) Aluminum sulfate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.0125:0.03:0.3:30:1. Add 25% of the mass of SiO2 in ZSM-48 seed crystal A1. The mass percentage of the added molecular sieve mother liquid to the total mass percentage of the molecular sieve mother liquid and water in step (1) is 20%;

[0119] (2) transferring the above mixture into a crystallization kettle and crystallizing at 170° C. for 48 h;

[0120] (3) After the crystallization is completed, the ZSM-48 molecular sieve DZ-3 is obtained by filtration and drying. DZ-3 is a rod-shaped molecular sieve with a ratio of about 6:1 in length to short diameter. The XRF analysis results of the obtained ZSM-48 molecular sieve and data such as specific surface area are shown in Table 1.

[0121] Comparative Preparation Example 4

[0122] (1) Aluminum sulfate, hexamethyldiamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain proportion, stirred for 30 minutes, and then silica sol was added. The molar ratio of each substance was n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2)=0.01:0.03:0.3:30:1. Add 5% of the mass of SiO2 in ZSM-48 seed crystal A1. The mass percentage of the added molecular sieve mother liquid to the total mass percentage of the molecular sieve mother liquid and water in step (1) is 20%;

[0123] (2) transferring the above mixture into a crystallization kettle and crystallizing at 170° C. for 48 h;

[0124] (3) After the crystallization is completed, the ZSM-48 molecular sieve DZ-4 is filtered and dried to obtain a rod-shaped ZSM-48 molecular sieve with a length-to-short diameter ratio of about 7: 1. The XRF analysis results of the obtained ZSM-48 molecular sieve and data such as specific surface area are shown in Table 1.

[0125] The following preparation examples are used to illustrate the preparation of the catalyst.

[0126] Example of Preparation of Hydroisomerization Catalyst

[0127] 100 g of each of the Z-1 to Z-4 molecular sieves in Preparation Examples 2-1 to 2-4 was mixed with 100 g of pseudo-boehmite, extruded and dried to obtain a carrier.

[0128] Pour 1 gram of dichlorotetraammineplatinum (containing 57.3% Pt by mass) into 100 grams of deionized water and stir until uniform. Pour 100 grams of the carrier into the above solution and soak at room temperature for 4 hours. Subsequently, the above catalyst precursor is dried at 120°C for 4 hours. Then, it is calcined under the condition of air flow, the calcination temperature is 450°C, and the time is 4 hours. The semi-finished catalyst is placed in a hydrogen atmosphere again and reduced at 400°C for 4 hours to obtain a hydroisomerization catalyst named IC-1 to IC-4.

[0129] Comparative Example of Preparation of Hydroisomerization Catalyst

[0130] The method is the same as the hydroisomerization catalyst preparation example, except that the molecular sieve is replaced with the DZ-1 to DZ-4 molecular sieves in the comparative preparation examples 1-4, and the obtained hydroisomerization catalysts are named DIC-1 to DIC-4.

[0131] The following examples are used to illustrate the multi-stage hydroisomerization catalyst combination method

[0132] The reaction device used is as follows Figure 4 As shown, Examples 1-5 and Comparative Examples 1-4 were loaded according to the catalyst combination in Table 2, and the Fischer-Tropsch wax was injected into the reactor for reaction. After the reaction, the product was distilled to remove light components less than 370 degrees, and the components greater than 370 degrees were analyzed and the yield was calculated. The reaction conditions and results are shown in Table 2.

[0133] Table 1

[0134]

[0135]

[0136] Table 2

[0137]

[0138] The multi-stage hydroisomerization catalyst combination method provided by the present invention helps to improve the efficiency of the catalytic reaction. When the method of the present invention is used to process oil products, the product pour point is lower and the product yield is higher.

[0139] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A multi-stage hydroisomerization catalyst combination method, the combination method comprising a first hydroisomerization catalyst and a second hydroisomerization catalyst sequentially loaded along a logistics direction, the first hydroisomerization catalyst loaded in a first hydrogenation reactor, the second hydroisomerization catalyst loaded in a second hydrogenation reactor, the first hydroisomerization catalyst and / or the second hydroisomerization catalyst each independently comprising a ZSM-48 molecular sieve, the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve being not less than 40, and the specific surface area of ​​the ZSM-48 molecular sieve being not less than 200 m 2 / g, the ZSM-48 molecular sieve has an ellipsoidal grain shape, a major diameter not exceeding 700nm and a major to minor diameter ratio of 1-3:1; The volume filling ratio of the first hydroisomerization catalyst to the second hydroisomerization catalyst is 0.5-1.5:

1.

2. The combined method according to claim 1, wherein: The specific surface area of ​​the ZSM-48 molecular sieve is 200-280m 2 / g.

3. The combined method according to claim 1, wherein: The length-to-short diameter ratio of ZSM-48 molecular sieve is 1-2:

1.

4. The combined method according to claim 1, wherein: The pore volume of ZSM-48 molecular sieve is 0.20-0.30 ml / g.

5. The combined method according to claim 1, wherein: The crystal size of the ZSM-48 molecular sieve is 300-700 nm.

6. The combined method according to claim 1, wherein: The crystal size of the ZSM-48 molecular sieve is 400-600 nm.

7. The combined method according to any one of claims 1 to 6, wherein: The preparation method of the ZSM-48 molecular sieve comprises the following steps: (1) providing a mixture containing a silicon source, an alkali source, an aluminum source, a template, water, a molecular sieve mother liquor, and a seed crystal; (2) subjecting the mixture to a crystallization reaction; the conditions of the crystallization reaction include: reacting at 20° C.-50° C. for 1-24 h, reacting at 50° C.-80° C. for 0.5-36 h, and then reacting at 80° C.-180° C. for 0.5-72 h; (3) The mixture obtained by the crystallization reaction in step (2) is subjected to solid-liquid separation to obtain ZSM-48 molecular sieve and molecular sieve mother liquor, and the molecular sieve mother liquor is returned to step (1); The method further comprises an optional step (4), which comprises: acidifying and precipitating the molecular sieve mother liquor, and then performing solid-liquid separation, and returning the obtained filtrate to step (1); The mass percentage of the added seed crystals in step (1) is 15-30% of the mass percentage of the silicon source, where the silicon source is calculated as SiO2; The seed crystals are ZSM-48 molecular sieve seed crystals, and the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve seed crystals is 45-500.

8. The combined method according to claim 7, wherein: The mass percentage of the added seed crystals in step (1) is 20-30% of the mass percentage of the silicon source.

9. The combined method according to claim 7, wherein: The mass percentage of the added molecular sieve mother liquid in step (1) to the total mass percentage of the molecular sieve mother liquid and water in step (1) is no more than 50%.

10. The combined method according to claim 9, wherein: The mass percentage of the added molecular sieve mother liquid in step (1) to the total mass percentage of the molecular sieve mother liquid and water in step (1) is 10-30%.

11. The combined method according to claim 7, wherein: The composition of each component in the mixture of step (1) calculated by molar amount satisfies the following relationship: R / SiO2=0.01-0.50; M + / SiO2=0.01-0.50; Al2O3 / SiO2=0-0.02; H2O / SiO2=5-50; Wherein, SiO2 refers to SiO2 in the silicon source, R represents the template, and M + Indicates alkaline source.

12. The combined method according to claim 11, wherein: The composition of each component in the mixture of step (1) calculated by molar amount satisfies the following relationship: R / SiO2=0.01-0.1; M + / SiO2=0.1-0.3; Al2O3 / SiO2=0.01-0.015; H2O / SiO2=10-30; Wherein, SiO2 refers to SiO2 in the silicon source, R represents the template, and M + Indicates alkaline source.

13. The combined method according to claim 7, wherein: The conditions of the crystallization reaction in step (2) include: reacting at 20°C-50°C for 6-24h, reacting at 50°C-80°C for 12-36h, and then reacting at 80°C-180°C for 48-72h.

14. The combined method according to claim 7, wherein: In step (4), the acidification precipitation comprises: adding acid to the molecular sieve mother liquor and adjusting the pH value to 3-7.

15. The combined method according to claim 14, wherein: In step (4), the acidification precipitation comprises: adding acid to the molecular sieve mother liquor and adjusting the pH value to 5-6.

5.

16. The combined method according to claim 7, wherein: The acidification deposition time is 0.5-4h.

17. The combined method according to claim 7, wherein: The preparation method of the seed crystal comprises contacting a reaction mixture under crystallization conditions, wherein the reaction mixture comprises a silicon source, an alkali source, an aluminum source, a template and water, and the crystallization conditions comprise: crystallizing at a temperature t1 for 5-24 hours, crystallizing at a temperature t2 for 0.5-36 hours, and crystallizing at a temperature t3 for 10-96 hours, 15°C≤t1<50°C, 50°C≤t2<100°C, and 100°C≤t3≤200°C; in an XRD diffraction peak pattern of the seed crystal after being calcined at 600°C for >3 hours, the peak height of the diffraction peak with a 2θ angle of 21°-22° is taken as a reference value, and the peak height of the diffraction peak with a 2θ angle of 7°-8° is not less than 70% of the reference value.

18. The combined method according to claim 1, wherein: The second hydroisomerization catalyst includes the ZSM-48 molecular sieve.

19. The combined method according to claim 1, wherein: The first hydroisomerization catalyst includes other types of one-dimensional ten-membered ring channel molecular sieves.

20. The combined method according to claim 19, wherein: The other types of one-dimensional ten-membered ring channel molecules are selected from at least one of ZSM-22, ZSM-23, SAPO-11 and SSZ-32.

21. The combined method according to claim 20, wherein: The other type of one-dimensional ten-membered ring channel molecular sieve is ZSM-22.

22. The combined method according to claim 1, wherein: The first hydroisomerization catalyst and the second hydroisomerization catalyst each independently contain an active metal and optionally a binder.

23. The combined method according to claim 22, wherein: The active metal is selected from at least one of Pt, Pd, Ni and Co.

24. The combined method according to claim 22, wherein: The binder is selected from at least one of alumina, pseudo-boehmite, silicon oxide, amorphous silicon aluminum and titanium oxide.

25. The combined method according to claim 22, wherein: Based on the total amount of the first hydroisomerization catalyst, the content of other types of one-dimensional ten-membered ring channel molecular sieves is 20-80% by weight, calculated as oxide, the content of the active metal is 0.1-2% by weight, and the content of the binder is 20-80% by weight.

26. The combined method according to claim 22, wherein: Based on the total amount of the second hydroisomerization catalyst, the content of ZSM-48 molecular sieve is 20-80% by weight, calculated as oxide, the content of the active metal is 0.1-2% by weight, and the content of the binder is 20-80% by weight.

27. A multi-stage hydroisomerization method, the method comprising: Under hydroisomerization conditions, the raw material to be hydroisomerized is injected into a hydroisomerization device for reaction, wherein the catalyst in the hydroisomerization device is loaded according to the combination method described in any one of claims 1 to 26.

28. The method according to claim 27, wherein: The raw material to be hydroisomerized is selected from at least one of cracking tail oil, bio-jet fuel production raw material, C5C6 isomerization raw material, and Fischer-Tropsch synthesis wax.

29. The method according to claim 28, wherein: The hydroisomerization conditions include: temperature of 200-500°C; pressure of 1-30MPa; volume space velocity of 0.1-5h -1 ; The volume ratio of hydrogen to oil is 50-3000.

30. The method of claim 29, wherein: The hydroisomerization conditions include: temperature of 250-400°C; pressure of 2-20 MPa; volume space velocity of 0.1-3 h -1 ; The volume ratio of hydrogen to oil is 300-3000.

31. The method according to any one of claims 27 to 30, wherein: The pressure in the first hydrogenation reactor is ≥5.0 MPa, the pressure in the second hydrogenation reactor is <5.0 MPa, and the temperature difference between the first hydrogenation reactor and the second hydrogenation reactor is ≥10°C.

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