CN109354037B - A kind of HZSM-5 molecular sieve with nanorod binding structure and its preparation method and application - Google Patents
A kind of HZSM-5 molecular sieve with nanorod binding structure and its preparation method and application Download PDFInfo
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Abstract
一种具有纳米棒捆绑结构的HZSM‑5分子筛是由多个长为1000‑3000 nm，粗为100‑200 nm的纳米棒晶体HZSM‑5分子筛进行同一轴向有序堆积形成的微米级颗粒。其制备是以正硅酸乙酯、四丙基氢氧化铵和偏铝酸钠为合成主原料进行均相水热合成；在合成料液中引入碳纳米管以调控水热过程中的晶体生长方向和最终结构；所得产物在空气气氛下焙烧一次性脱除模板剂和碳管，形成具备纳米棒捆绑结构的NaZSM‑5分子筛。该结构分子筛经酸化后具有强的传质效应和高的酸催化性能，特别适用于甲醇制烃反应。
A HZSM-5 molecular sieve with a nanorod binding structure is a micron-sized particle formed by orderly stacking a plurality of nanorod crystal HZSM-5 molecular sieves with a length of 1000-3000 nm and a thickness of 100-200 nm in the same axial direction. Its preparation is homogeneous hydrothermal synthesis using ethyl orthosilicate, tetrapropylammonium hydroxide and sodium metaaluminate as the main raw materials for synthesis; carbon nanotubes are introduced into the synthesis liquid to control the crystal growth in the hydrothermal process orientation and final structure; the resulting product was calcined in an air atmosphere to remove the template agent and carbon tubes at one time to form a NaZSM-5 molecular sieve with a nanorod-bundled structure. The structural molecular sieve has strong mass transfer effect and high acid catalytic performance after acidification, and is especially suitable for methanol to hydrocarbon reaction.
Description
Technical Field
The invention relates to an H-ZSM-5 molecular sieve catalyst with a nanorod binding structure and a preparation method and application thereof.
Background
The methanol-to-hydrocarbon reaction is an important chemical reaction in C1 chemistry, is an important way for synthesizing basic chemical and chemical products by a non-petroleum route at present, and is considered as a bridge between the coal or natural gas chemical industry and the modern petrochemical industry. In this process, acidic molecular sieves are important catalysts. As a crystalline silicate material, the ZSM-5 molecular sieve has excellent methanol-to-hydrocarbon reaction performance due to good thermal stability, strong acidity and an ordered microporous structure. However, the ZSM-5 molecular sieve has a regular and ordered microporous structure, so that the diffusion of reaction molecules is limited, acid sites in the molecular sieve cannot fully contact with reaction raw materials for reaction, and the reaction activity is reduced. More importantly, the micropore structure can block the outward diffusion of macromolecular hydrocarbon products, so that the accumulation of related reaction products in micropores is caused, the mass transfer effect and the catalytic conversion of macromolecules are seriously influenced, and the catalytic efficiency is lower and the catalyst is quickly inactivated.
In order to solve the diffusion limitation problem, the diffusion performance can be improved by introducing mesopores into a ZSM-5 microporous system or synthesizing a nanoscale molecular sieve. The introduction of the mesopores into the micropore system can promote the diffusion of the carbon deposit precursor from the inner surface to the outer surface, reduce the possibility of generating carbon deposit by polymerization of the carbon deposit precursor, promote the contact of reactant molecules and acid sites, and have good promotion effects on reaction activity and reaction stability. There are two general methods for introducing mesopores into ZSM-5 crystals, one is in-situ synthesis introduction, and the other is chemical post-treatment. In-situ introduction generally requires adding a mesoporous template agent in hydrothermal synthesis to induce the formation of mesopores. CN105271299A discloses a mesoporous ZSM-5 molecular sieve synthesized by using a bridged silsesquioxane monomer as a mesoporous template, and a large amount of intragranular mesopores with regular pore size distribution are introduced on the basis of micropores. The ZSM-5 mesoporous channels synthesized by the method are uniform, but the industrial application of the mesoporous ZSM-5 synthesized by the method is limited by the lower yield and the environmental pollution generated by removing the template agent. The chemical post-treatment is a method for introducing mesopores, which is simple to operate and comprises selective dealumination and selective desilication. Among them, selective dealumination is usually carried out by means of hydrothermal treatment or acid treatment, but damaged Al species are easy to remain after treatment, and blocking of the pore channels is not favorable for improvement of the mass transfer performance of the zeolite molecular sieve. Selective desiliconization is the most efficient method for introducing mesopores, and the introduction of the mesopores is usually realized by an alkali treatment method, so that the mass transfer performance of the zeolite is obviously improved. However, this method often results in poor yields of the final product due to differences in the distribution of the aluminum in the ZSM-5 bulk phase (more external than internal), more inhibitory removal of external silicon by aluminum, internal preferential desilication, formation of large and even Mesoporous structures, difficulty in achieving uniform Mesoporous architecture, and disposal of large amounts of the molecular sieve structured material (Wang Y, Lin M, Tuel a, microporus and mesoporus Materials 2007,102(1-3), 80-85).
The grain size is reduced, the prepared nano HZSM-5 molecular sieve can effectively increase the external specific surface area, expose more acid sites to participate in the reaction, shorten the diffusion path, reduce the retention time of macromolecular hydrocarbons in the pore channel, effectively reduce the carbon deposition generation rate, prolong the service life of the catalyst and improve the catalytic efficiency. However, the nano HZSM-5 molecular sieve is difficult to separate from the reaction system during the synthesis process, and the synthesized nano HZSM-5 molecular sieve has low crystallinity and more defect sites (Zhang H, Ma Y, Song K, et al. journal of Catalysis 2013,302, 115-125). The layered ZSM-5 molecular sieve can have a large size and a short diffusion path, the specific surface area of the layered ZSM-5 molecular sieve can reach 2 times of that of the conventional molecular sieve, and the anti-carbon performance is obviously improved, but the type of molecular sieve needs a bifunctional surfactant (Choi M, Na K, Kim J, Sakamoto Y, Terasaki O, Ryoo R, Nature 2009,461(7261), 246-one 249) with complicated preparation steps. Therefore, it is significant to synthesize a ZSM-5 molecular sieve having a large particle size but good diffusion properties.
Disclosure of Invention
The invention aims to provide a nanorod bundled HZSM-5 molecular sieve, and a preparation method and application thereof. The obtained molecular sieve can effectively improve the mass transfer effect and the catalytic conversion of macromolecules in the catalytic reaction process, and the separation process is easy, thereby being easy to realize industrialization.
The invention provides an HZSM-5 molecular sieve with a nanorod binding structure, wherein the binding structure of the molecular sieve is micron-sized particles formed by orderly stacking 50-100 nanorod HZSM-5 molecular sieves with the length of 1000-3000nm and the thickness of 100-200nm in the same axial direction, and SiO of the micron-sized particles is SiO2/Al2O3The molar ratio is 30-600, the external specific surface is 106-142m2g-1The mesoporous volume is 0.13-0.65cm3g-1。
The invention provides a preparation method of an HZSM-5 molecular sieve with a nanorod bundled structure, which comprises the following steps:
(1) mixing ethyl orthosilicate, tetrapropyl ammonium hydroxide and deionized water to obtain solution A; mixing carbon nanotubes with different diameters and deionized water, carrying out ultrasonic treatment to obtain a solution B, adding the solution B into the solution A, and aging to prepare a silicon precursor solution, wherein the molar ratio of ethyl orthosilicate to deionized water in the solution A is 1: 50-100, wherein the molar ratio of the carbon nano tubes in the solution B to the deionized water is 1: 15-60 parts of;
(2) dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution for continuous aging;
(3) carrying out rotary crystallization, centrifugation, washing, drying, primary roasting, ion exchange and secondary roasting on the solution to obtain the HZSM-5 molecular sieve with the nanorod bundled structure with different sizes;
wherein: tetraethoxysilane with SiO2Calculated as Al, sodium metaaluminate2O3Calculated by TPAOH, calculated by tetrapropylammonium hydroxide and calculated by Na, calculated by sodium hydroxide2Calculated by O, the molar ratio of each substance of the carbon nano tube calculated by MWCNT is SiO2：Al2O3：TPAOH：Na2O：MWCNT＝60:(0.1-2.0):(50-70):(1.5-60):(20-100)。
The ultrasonic treatment in the step (1) is carried out for 30-60min at normal temperature, the aging process is carried out by stirring for 15-30h at 50-90 ℃, and the diameter of the adopted carbon nano tube is 10-20 nm;
in the step (2), the mixed feed liquid of sodium hydroxide and sodium metaaluminate is dropwise added into the silicon precursor solution in the step (1) by a peristaltic pump, and the aging process is to stir for 3-8h at 50-90 ℃.
In the step (3), the rotary crystallization process is performed in a homogeneous reactor at 100-180 ℃ for 30-80 h.
In step (3), the first calcination is performed to further remove the residual organic template and carbon nanotubes, the calcination process is usually performed in an air atmosphere at a temperature of 500-600 ℃ for 2-10h, and the second calcination is performed to remove NH in ion exchange4 +The roasting process is to roast at 550 ℃ for 6H to obtain the H-type ZSM-5.
The operation conditions of applying the obtained HZSM-5 molecular sieve to the methanol-to-hydrocarbon reaction are as follows: and tabletting and crushing the obtained powder, screening 80-100-mesh particles, and evaluating the reaction performance of the methanol-to-hydrocarbon reaction in a fixed bed reactor. The reaction temperature is 380--1。
The invention discloses a method for preparing HZSM-5 molecular sieve with nanorod bundled structure and application thereof, and the invention has the following remarkable advantages:
(1) according to the method, the carbon nano tubes are added into the feed liquid for the rotary hydrothermal synthesis of the ZSM-5 molecular sieve, the surface hydrophobicity and the stirring effect generated in the rotary synthesis process of the micron size of the carbon nano tubes can inhibit the transverse growth of single crystal grains of the molecular sieve, and finally micron-sized particles which are small in transverse size and have a binding structure in the same axial direction are obtained.
(2) The molecular sieve product prepared by the invention has high crystallinity and few defects, and the particle structure has micron size which enables the particle structure to be easily separated from a synthetic solution.
(3) The molecular sieve prepared by the invention has a binding and stacking structure, generates mesopores and has small transverse size, and is beneficial to improving the mass transfer and carbon deposition resistance of molecules in the reaction of preparing hydrocarbon from methanol.
(4) The structure of the HZSM-5 molecular sieve with the nanorod bundled structure can be optimally regulated and controlled by regulating and controlling the formula of raw materials (such as the addition amount of carbon nanotubes, the silicon-aluminum ratio, the water-silicon ratio and the like) influencing the grain growth of the molecular sieve and the preparation process parameters (such as the temperature, the time and the like of the rotary crystallization) in the preparation process.
(5) The nanorod HZSM-5 prepared by the invention and bundled in the same axial direction shows good catalytic stability, and has the advantages of reaction temperature of 380-450 ℃, reaction pressure of 0.3-2.0MPa and mass space velocity WHSV of 2.0-12.0h-1Under the condition of (1), the conversion rate reaches 100%, the catalytic life is 105-132h, and the liquid hydrocarbon yield is 23.0-26.5%.
Drawings
FIG. 1 is an XRD pattern of HZSM-5 having a nanorod bundled structure in example 1.
FIG. 2 is a TEM image of the nanorod bundled structure HZSM-5 of example 1.
FIG. 3 is an enlarged TEM image of the nanorod-bundled structure HZSM-5 in example 1.
Detailed Description
The following further details embodiments of the present invention by way of specific embodiments:
example 1
(1) Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water with certain composition, wherein SiO is2：H2The molar ratio of O is 1: 50, obtaining solution A; carbon nanotubes with the diameter of 10nm and deionized water are mixed according to the molar ratio of 1: 15, mixing, and carrying out ultrasonic treatment for 30min to obtain a solution B; adding the solution B into the solution A, and aging in a water bath kettle at 50 ℃ for 28h to prepare a silicon precursor solution.
(2) Dropwise adding the mixed solution of sodium hydroxide and sodium metaaluminate into the solution, and continuously aging for 5.5h at 50 ℃. The feeding molar composition of each raw material is as follows: 60SiO2：1Al2O3：60TPAOH：3Na2O：20MWCNT。
(3) Placing the above solution into a stainless steel crystallization kettle, placing into a homogeneous reactor, performing rotary crystallization at 120 deg.C for 72 hr, centrifuging, washing, drying, grinding, calcining at 550 deg.C in air atmosphere for 6 hr to obtain Na type ZSM-5 molecular sieve, and adding 0.8M NH4NO3Ion exchange of the solution is carried out for 3h multiplied by 3 times, and the solution is roasted for 6h in a muffle furnace at the temperature of 550 ℃, thus obtaining the HZSM-5 molecular sieve, SiO, bundled by 50-60 nanorods with the length of 1500nm and the thickness of 200nm2：Al2O3The ratio is 60.
In the method, the crystal form of the prepared molecular sieve is characterized by an XRD means. The test apparatus was an X-ray diffractometer model Rigaku D/max2500, japan, which used a Cu target K α ray (λ: 0.154056nm) as a radiation source, a tube voltage of 40kV, and a tube current parameter of 30 mA. The scanning speed is 8 DEG/min-1Step size 0.01 deg. and scan range 5-50 deg.. The X-ray diffraction results showed that the sample prepared in example 1 had the basic characteristic diffraction peaks of the MFI structure in the ranges of 7-10 ° and 22-25 °, indicating that the sample synthesized in example 1 had the HZSM-5 molecular sieve crystal structure, and the results are shown in fig. 1.
TEM characterization was performed on a JEOL-JEM-2100F field emission transmission electron microscope, sample preparation: the sample is developed by an agate mortar to be less than 200 meshes, dispersed by an ethanol solution, subjected to ultrasonic treatment for 30min by ultrasonic waves, dropped on a copper mesh carbon film to prepare a sample, and naturally dried. Then, photographing was performed under the condition that the acceleration voltage was 200 kV. The transmission electron microscope analysis shows that the prepared HZSM-5 molecular sieve sample has a nanorod bundled structure, and the obtained results are shown in the figure 2 and the figure 3.
The texture properties of the molecular sieve, such as external specific surface area, mesoporous pore volume and the like, are tested by a BET method on a Behcet 3H-2000PS2 model static capacity method specific surface area pore size analyzer, and a sample before measurement is carried out at 250 ℃ and 10 DEG C-2And (3) processing for 4h under the condition of Pa, and then carrying out nitrogen adsorption-desorption process on the sample at-196 ℃. The external specific surface area and the mesoporous pore volume of the prepared HZSM-5 molecular sieve with the nanorod bundled structure are shown in Table 1.
The HZSM-5 molecular sieve obtained above is used for the reaction of preparing hydrocarbon by methanol, and the operation condition is: the obtained catalyst is pressed into tablets and sieved to prepare particles of 80-100 meshes, and the particles are mixed with quartz sand of 40-60 meshes to be subjected to reaction evaluation of preparing hydrocarbon from methanol in a fixed bed reactor. The reaction temperature is 430 ℃, the reaction pressure is 0.5MPa, and the mass space velocity WHSV is 4.7h-1And after the reaction product passes through a condenser and a gas-liquid separator, the liquid phase product is stored in a liquid storage tank. The oil phase product was analyzed by a gas chromatograph analyzer model SHIMADZU GC2014C, and the results of catalyst life, liquid hydrocarbon yield and methanol conversion are shown in table 1.
Example 2
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：1.5Al2O3：60TPAOH：3Na2O: 80 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 80, obtaining a solution A; and then mixing carbon nanotubes with the diameter of 15nm and deionized water according to a molar ratio of 1: 45, carrying out ultrasonic treatment for 30min, adding the solution A, and aging at 70 ℃ for 22h to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 5.5h at 70 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 72 hours at the temperature of 160 ℃. Then centrifuging, washing, drying, roasting at 600 deg.C for 2 hr to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, and the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve, SiO, bound by 55-70 nanorods with the length of 2000nm and the thickness of 180nm2：Al2O3The ratio is 40.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 2, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted at a reaction temperature of 400 ℃, a reaction pressure of 1.0MPa, and a mass space velocity WHSV of 4.7h-1Evaluation of catalytic reaction, the nanorod-bundled structure obtained in example 2The results of HZSM-5 molecular sieve lifetime, liquid hydrocarbon yield and methanol conversion are shown in Table 1.
Example 3
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：2Al2O3：60TPAOH：3Na2O: 100 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 36, obtaining a solution A; and then mixing carbon nanotubes with the diameter of 20nm and deionized water according to a molar ratio of 1: 60, carrying out ultrasonic treatment for 30min, adding the solution A, and aging at 90 ℃ for 18h to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 5.5h at 90 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 72 hours at the temperature of 150 ℃. Then centrifuging, washing, drying, roasting at 500 deg.C for 10 hr to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, and the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve, SiO, bound by 50-100 nano rods with the length of 3000nm and the thickness of 100nm2：Al2O3The ratio is 30.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 3, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted so that the reaction temperature was 380 ℃, the reaction pressure was 2.0MPa, and the mass space velocity WHSV was 12.0h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure prepared in example 3 are shown in table 1.
Example 4
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：1.5Al2O3：60TPAOH：1.5Na2O: 50 MWCNT. Mixing ethyl orthosilicate, tetrapropyl ammonium hydroxide and deionized waterWherein SiO is2：H2The molar ratio of O is 1: 500, obtaining a solution A; and then mixing carbon nanotubes with the diameter of 10nm and deionized water according to a molar ratio of 1: 30, carrying out ultrasonic treatment for 30min, adding the solution A, and aging at 80 ℃ for 22h to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 8 hours at 80 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 48 hours at the temperature of 170 ℃. Then centrifuging, washing, drying, roasting at 550 ℃ for 6h in air atmosphere to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, and the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve, SiO, bound by 50-100 nano rods with the length of 2000nm and the thickness of 100nm2：Al2O3The ratio is 40.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 4, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted so that the reaction temperature was 430 ℃, the reaction pressure was 0.5MPa, and the mass space velocity WHSV was 12.0h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure obtained in example 4 are shown in table 1.
Example 5
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：1Al2O3：60TPAOH：4500H2O：3Na2O: 50 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 75, obtaining solution A; and then mixing carbon nanotubes with the diameter of 10nm and deionized water according to a molar ratio of 1: 30, adding the solution A after ultrasonic treatment for 30min, and aging for 20h at 80 ℃ to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 5 hours at 80 ℃. Then will beThe solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 48 hours at the temperature of 170 ℃. Then centrifuging, washing, drying, roasting at 600 deg.C for 2 hr to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, and the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve, SiO, bound by 60-90 nanorods with the length of 1500nm and the thickness of 120nm2：Al2O3The ratio is 60.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 5, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted so that the reaction temperature was 430 ℃, the reaction pressure was 0.5MPa, and the mass space velocity WHSV was 2.0h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure obtained in example 5 are shown in table 1.
Example 6
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：0.5Al2O3：60TPAOH：6Na2O: 50 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 100, obtaining a solution A; and then mixing carbon nanotubes with the diameter of 10nm and deionized water according to a molar ratio of 1: 30, adding the solution A after ultrasonic treatment for 30min, and aging for 18h at 80 ℃ to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 3h at 80 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 48 hours at the temperature of 170 ℃. Then centrifuging, washing, drying, roasting at 500 deg.C for 10 hr to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange of the solution is carried out for 3h multiplied by 3 times, and roasting is carried out for 6h at 550 ℃ to obtain the nano-rod binding by 55-70 nano-rods with the length of 1000nm and the thickness of 180nmHZSM-5 molecular sieve, SiO2：Al2O3The ratio is 120.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 6, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted so that the reaction temperature was 380 ℃, the reaction pressure was 0.3MPa, and the mass space velocity WHSV was 4.7h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure obtained in example 6 are shown in table 1.
Example 7
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：1Al2O3：50TPAOH：6Na2O: 60 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 75 obtaining a solution A; and then mixing carbon nanotubes with the diameter of 20nm and deionized water according to a molar ratio of 1: 45, adding the solution A after ultrasonic treatment for 30min, and aging for 30h at 50 ℃ to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 8 hours at 50 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 80 hours at the temperature of 100 ℃. Then centrifuging, washing, drying, roasting at 500 deg.C for 10 hr to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, and the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve, SiO, bound by 60-80 nanorods with the length of 1000nm and the thickness of 120nm2：Al2O3The ratio is 60.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 7, and the external specific surface area and the mesoporous volume are shown in table 1.
Preparation of nail in example 1The evaluation conditions of the alcohol-to-hydrocarbon reaction were that the reaction temperature was 380 ℃, the reaction pressure was 1.0MPa, and the mass space velocity WHSV was 4.7h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure obtained in example 7 are shown in table 1.
Example 8
The molar composition of each raw material in example 1 was adjusted to: 60SiO2：0.5Al2O3：60TPAOH：3Na2O: 40 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 75, obtaining solution A; and then mixing carbon nanotubes with the diameter of 15nm and deionized water according to a molar ratio of 1: 30, adding the solution A after ultrasonic treatment for 30min, and aging for 20h at 70 ℃ to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 4.5h at 70 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 25 hours at the temperature of 150 ℃. Then centrifuging, washing, drying, roasting at 550 ℃ for 6h in air atmosphere to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, and the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve, SiO, bound by 50-80 nanorods with the length of 2000nm and the thickness of 150nm2：Al2O3The ratio is 120.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 8, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted so that the reaction temperature was 450 ℃, the reaction pressure was 0.5MPa, and the mass space velocity WHSV was 2.0h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure obtained in example 8 are shown in table 1.
Example 9
Adjustment of the sources in example 1The material molar composition is as follows: 60SiO2：0.1Al2O3：70TPAOH：1.5Na2O: 20 MWCNT. Mixing ethyl orthosilicate, tetrapropylammonium hydroxide and deionized water, wherein SiO is2：H2The molar ratio of O is 1: 75, obtaining solution A; and then mixing carbon nanotubes with the diameter of 10nm and deionized water according to a molar ratio of 1: 15, carrying out ultrasonic treatment for 30min, adding the solution A, and aging at 90 ℃ for 15h to prepare a silicon precursor solution. Dropwise adding the mixed feed liquid of sodium hydroxide and sodium metaaluminate into the silicon precursor solution, and continuously aging for 3 hours at 90 ℃. Then the solution is put into a stainless steel crystallization kettle and put into a homogeneous reactor for rotary crystallization for 30 hours at 180 ℃. Then centrifuging, washing, drying, roasting at 600 deg.C for 2 hr to obtain Na-type ZSM-5 molecular sieve, and finally adding 0.8M NH4NO3Ion exchange is carried out on the solution for 3h multiplied by 3 times, the solution is roasted for 6h at 550 ℃ to obtain the HZSM-5 molecular sieve bound by 60-80 nanorods with the length of 2500nm and the thickness of 170nm, and SiO is finally fed2：Al2O3The ratio is 600.
The method for testing the external specific surface area and the mesoporous volume of the molecular sieve in example 1 is adopted to characterize the HZSM-5 molecular sieve with the nanorod bundled structure prepared in example 9, and the external specific surface area and the mesoporous volume are shown in table 1.
The conditions for evaluating the methanol to hydrocarbon reaction in example 1 were adjusted so that the reaction temperature was 380 ℃, the reaction pressure was 0.5MPa, and the mass space velocity WHSV was 2.0h-1The catalytic reaction evaluation was carried out, and the results of the life, liquid hydrocarbon yield and methanol conversion of the HZSM-5 molecular sieve having a nanorod bundled structure obtained in example 9 are shown in table 1.
TABLE 1 texture Properties of samples referred to in examples 1-9 and their catalytic reaction Performance in the MTH reaction
Note: the liquid hydrocarbon yield in table 1 refers to the maximum liquid hydrocarbon yield in the case where the catalyst catalyzes the MTH reaction, the lifetime is the reaction time taken for the catalytic liquid hydrocarbon yield to decrease to 5%, and the methanol conversion rate is the methanol conversion rate corresponding to the decrease in the liquid hydrocarbon yield of the MTH reaction to 5%.
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