CN116020531A

CN116020531A - Binder-free ZSM-35 molecular sieve catalyst and preparation method and application thereof

Info

Publication number: CN116020531A
Application number: CN202111250648.0A
Authority: CN
Inventors: 吕建刚; 刘波; 王迪; 邵益; 许烽
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2023-04-28

Abstract

The invention discloses a non-binder ZSM-35 molecular sieve catalyst, a preparation method and application thereof. The binder-free ZSM-35 molecular sieve catalyst takes the weight of aluminum in the catalyst as a reference, the content of skeleton aluminum is 58-82%, and the content of non-skeleton aluminum is 18-42%. The catalyst is used for carbon tetraolefin skeleton isomerization reaction, and has higher yield of target product isobutene and good long-term stability.

Description

Binder-free ZSM-35 molecular sieve catalyst and preparation method and application thereof

Technical Field

The invention relates to the field of olefin skeleton isomerization, in particular to a non-binder ZSM-35 molecular sieve catalyst for n-butene skeleton isomerization, a preparation method thereof and application thereof in n-butene skeleton isomerization reaction.

Background

With the rapid development of oil refining and petrochemical industries, the processing and utilization of carbon four resources are gradually more visible. Isobutene is a carbon four component with wide application, can be used for producing MTBE blended gasoline or producing high-purity isobutene products, and can also be used for producing a plurality of high-added-value fine chemical products such as polyisobutene and the like, so that n-butene is converted into isobutene through skeleton isomerization reaction, and the isobutene has good application value.

In the early 70 th century, oxide catalysts such as alumina are mainly used, the market demand of isobutene is suddenly increased to the 90 th year, meanwhile, the discovery of molecular sieve catalysts enables the n-butene skeleton isomerization process to be rapidly developed, and the molecular sieve catalytic process adopts molecular sieves such as silicon-aluminum ZSM type and silicon-aluminum-phosphorus-SAPO type as the n-butene skeleton isomerization catalyst, so that the activity of the n-butene skeleton isomerization catalyst is more ideal than that of the traditional oxide. Research results in the last thirty years show that the FER molecular sieve catalyst with ten-membered ring pore channels and special FER cages is more suitable for the skeletal isomerization reaction of linear olefins.

Method for preparing isobutene by skeletal isomerization of n-butene disclosed in CN103772112A adopts SiO ₂ /Al ₂ O ₃ The sodium-potassium hydrogen type FER molecular sieve with the molar ratio of 10-50 is used as a catalyst, and the catalyst is prepared by mixing and molding the sodium-potassium hydrogen type FER molecular sieve, a binder, an extrusion aid, inorganic acid and water. Although the catalyst can make the yield reach the stable period in a short time, the yield of the target product isobutene is still lower and still needs to be further improved.

The catalyst needs to be added with a certain amount of binder in the forming process, and the binder-free catalyst converts the binder into the effective components of the molecular sieve, so that the binder-free catalyst contains no binder or only a small amount of binder, and therefore, the binder-free catalyst has higher molecular sieve content in unit volume, higher catalyst activity and higher treatment load, and meanwhile, the binder does not block pore channels any more, so that the catalyst has higher utilization efficiency and stronger carbon deposition resistance. CN109701606a discloses a skeletal isomerization catalyst comprising, in weight percent: 95.5-100% molecular sieve (such as ZSM-35 molecular sieve) and 0-4.5% binder, and is prepared by mixing molecular sieve powder and binder to obtain precursor, subjecting the binder to hydrothermal reaction to convert the binder into molecular sieve, subjecting the molecular sieve to ammonium exchange, and calcining to obtain the binder-free catalyst.

For the n-butene skeletal isomerization reaction, the research and development of a catalyst with higher activity and selectivity and better stability and a simple preparation method thereof are technical problems which are constantly strived for in the field.

Disclosure of Invention

Aiming at the problems of poor stability, low yield of target products and the like of the normal butene skeletal isomerization catalyst in the prior art, the invention provides a novel binder-free ZSM-35 molecular sieve catalyst for normal butene skeletal isomerization, and a preparation method and application thereof. The non-binder ZSM-35 molecular sieve catalyst has the characteristics of high yield and excellent stability of target products when being used for n-butene skeleton isomerization.

The first aspect of the invention provides a binderless ZSM-35 molecular sieve catalyst in which the content of framework aluminium is 58% to 82%, preferably 65% to 80%, and the content of non-framework aluminium is 18% to 42%, preferably 20% to 35% based on the weight of aluminium in the catalyst.

In the present invention, the aluminum in the catalyst is divided into framework aluminum and non-framework aluminum.

According to some embodiments of the invention, the catalyst has a total acid amount of 0.40 to 0.70 mmol.g ^-1 Preferably 0.45 to 0.70 mmol.g ^-1 。

According to some embodiments of the invention, the catalyst has a strong acid content of 55% -75% and a strong acid content of 25% -45%; preferably, the content of the medium strong acid is 60% -70%, and the content of the strong acid is 30% -40%.

In the present invention, the binder-free is a binder having a mass content of 5% or less, preferably 3% or less, and more preferably 2% or less, based on the weight of the catalyst.

According to some embodiments of the invention, the catalyst has a specific surface area of 250 to 350m ² ·g ^-1 Preferably 270 to 320m ² ·g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the Pore volume of 0.1-0.3 cm ³ ·g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The average pore diameter is 2.0-5.0 nm.

According to some embodiments of the invention, the SiO of the catalyst ₂ /Al ₂ O ₃ The molar ratio is 10-30, preferably 15-25; na (Na) ₂ The mass content of O is less than or equal to 0.03 percent.

According to some embodiments of the invention, the catalyst has a radial crush strength of 4 to 10 N.mm ^-1 Preferably 5 to 8 N.multidot.mm ^-1 。

The second aspect of the invention provides a method for preparing a binder-free ZSM-35 molecular sieve catalyst, comprising the following steps:

a) Mixing a silicon source, an aluminum source, a first alkali source, a binder precursor and an auxiliary agent, molding, first drying and first roasting to obtain a precursor;

b) Mixing a solution containing a second alkali source and a template agent with the precursor obtained in the step a), performing hydrothermal crystallization, drying and roasting to obtain a catalyst intermediate;

c) And c), carrying out ammonium exchange on the catalyst intermediate obtained in the step b), and then carrying out steam treatment to obtain the non-binder ZSM-35 molecular sieve catalyst.

According to some embodiments of the invention, the silicon source of step a) is white carbon black. The aluminum source is one or more of sodium aluminate, aluminum sulfate, kaolin and pseudo-boehmite. The first alkali source is one or more of sodium carbonate and potassium carbonate. The binder is amorphous silica, and the binder precursor is silica sol. The auxiliary agent is one or more of sesbania powder, cellulose and starch.

According to some embodiments of the invention, the shaping described in step a) may be performed by conventional shaping methods, such as extrusion, etc. The first drying conditions are as follows: the first drying temperature is 80-200 ℃, the first drying time is 12-48 h, and the first roasting condition is as follows: the first roasting temperature is 400-600 ℃, and the first roasting time is 3-12 h. Both the first drying and the first calcination are carried out under an oxygen-containing atmosphere, such as air.

According to some embodiments of the invention, the second alkali source of step b) is one or more of sodium hydroxide, potassium hydroxide. The template agent is one or more of cyclohexane, n-butylamine, 1, 4-cyclohexanediamine and ethylenediamine.

According to some embodiments of the invention, in the solution containing the second alkali source and the template agent in the step b), the mass concentration of the second alkali source is 1% -3%, and the mass concentration of the template agent is 3% -15%.

According to some embodiments of the invention, in step a) a silicon source, an aluminum source, a first alkali source, a binder precursor and an auxiliary agent are mixed, wherein the silicon source is in the form of SiO ₂ The aluminum source is Al ₂ O ₃ Calculated as oxide M from a first alkali source ₂ The material ratios of the silicon source, the aluminum source and the first alkali source are as follows: siO (SiO) ₂ With Al ₂ O ₃ The molar ratio of (2) is 10-20: 1, M ₂ O and Al ₂ O ₃ The molar ratio of (2) is 0.4-1.0: 1. the usage amount of the binder precursor is calculated by the binder and is calculated by the silicon source and the SiO ₂ Meter and aluminum source in Al ₂ O ₃ 40-60% of total mass, and the dosage of the auxiliary agent is silicon source and SiO ₂ Meter and aluminum source in Al ₂ O ₃ 1 to 5 percent of the total mass.

According to some embodiments of the invention, step b) mixes a solution containing a second alkali source and a templating agent with the precursor obtained in step a), the second alkali source being present as oxide M in the resulting mixture ₂ O meter, M ₂ O and step a) aluminum source with Al ₂ O ₃ The calculated molar ratio is 0.30-0.6: 1, a step of; template agent and step a) aluminum source are prepared by using Al ₂ O ₃ The molar ratio is 1-6: 1.

according to some embodiments of the invention, the hydrothermal crystallization in step b) adopts gradient temperature rising crystallization, the initial temperature is 80-140 ℃, the end temperature is 150-200 ℃, and the total crystallization time is 48-192 h. Wherein, the gradient heating crystallization adopts at least 2 gradients, further 2-10 gradients, and the temperature difference between two adjacent gradients is at least 5 ℃ or more, further 10 ℃ or more, and preferably 10-30 ℃. Further, the crystallization time per gradient is 10 to 30 hours. The crystallization time of each gradient may be the same or different.

According to some embodiments of the invention, after the hydrothermal crystallization of step b) is completed, preferably after a washing treatment before the second drying, deionized water washing may be used. The second drying conditions are as follows: the drying temperature is 80-120 ℃, the drying time is 12-48 h, and the second roasting condition is as follows: roasting temperature is 400-600 ℃, and roasting time is 3-12 h. The second drying and the second calcination are both carried out under an oxygen-containing atmosphere, such as air.

According to some embodiments of the invention, the ammonium exchange in step c) may be carried out by conventional methods, and the ammonium salt used may be one or more of ammonium nitrate, ammonium acetate, ammonium sulphate, etc. The mass concentration of the ammonium salt solution can be 5% -15%, and the ammonium exchange conditions are as follows: the temperature is 30-90 ℃, and the ammonium exchange time is 0.5-2 h each time. The ammonium exchange may be performed a plurality of times, and may further be performed 2 to 6 times.

According to some embodiments of the invention, the steam treatment process of step c) is carried out in a rotary tube furnace, preferably at a rotational speed of 1rpm or more, further 1 to 5rpm.

According to some embodiments of the invention, the conditions of the water vapour treatment according to step c) are as follows: the mass airspeed of the water vapor is 0.3 to 5 hours ^-1 Preferably 0.5 to 3.0h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The treatment temperature is 400-700 ℃, preferably 450-600 ℃; the treatment pressure is 0-1 MPa, preferably 0-0.5 MPa; the treatment time is 1 to 10 hours, preferably 3 to 8 hours.

According to some embodiments of the present invention, the binderless ZSM-35 molecular sieve catalyst prepared by the method, wherein the content of framework aluminum is 58% to 82%, preferably 65% to 80%, and the content of non-framework aluminum is 18% to 42%, preferably 20% to 35%, based on the weight of aluminum in the catalyst.

According to some embodiments of the invention, the total acid amount of the binderless ZSM-35 molecular sieve catalyst prepared by the method is 0.40 to 0.70 mmol.g ^-1 Preferably 0.45 to 0.70 mmol.g ^-1 。

According to some embodiments of the invention, the binder-free ZSM-35 molecular sieve catalyst prepared by the method has a strong acid content of 55% -75% and a strong acid content of 25% -45%; preferably, the content of the medium strong acid is 60% -70%, and the content of the strong acid is 30% -40%.

According to some embodiments of the invention, the specific surface area of the binderless ZSM-35 molecular sieve catalyst prepared by the method is 250-350 m ² ·g ^-1 Preferably 270 to 320m ² ·g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the Pore volume of 0.1-0.3 cm ³ ·g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The average pore diameter is 2.0-5.0 nm.

According to some embodiments of the invention, the method produces a binderless ZSM-35 molecular sieve catalyst of SiO ₂ /Al ₂ O ₃ The molar ratio is 10-30, preferably 15-25; na (Na) ₂ The mass content of O is less than or equal to 0.03 percent.

According to some embodiments of the invention, the binderless ZSM-35 molecular sieve catalyst prepared by the method has a radial crush strength of from 4 to 10 N.mm ^-1 Preferably 5 to 8 N.multidot.mm ^-1 。

The third aspect of the invention also provides the use of a catalyst according to the first aspect of the invention or a catalyst prepared by a preparation method according to the second aspect of the invention in a skeletal isomerisation reaction of a carbon tetraolefin.

According to some embodiments of the invention, the carbon tetraolefin is n-butene or a mixed hydrocarbon containing n-butene, and more preferably the mass content of 1, 3-butadiene or other diolefin in the mixed hydrocarbon is less than 1%.

According to some embodiments of the invention, the temperature of the reaction is 200-500 ℃, preferably 300-450 ℃.

According to some embodiments of the invention, the pressure of the reaction is between 0 and 1MPa, preferably between 0 and 0.5MPa, more preferably between 0 and 0.2MPa.

According to some embodiments of the invention, the mass space velocity of the carbon tetraolefin is 0.1-10 h ^-1 Preferably 0.5 to 6 hours ^-1 。

Compared with the prior art, the invention has the following beneficial effects:

1. the inventor of the invention has found through a great deal of researches that by controlling the content of framework aluminum and non-framework aluminum in the binderless ZSM-35 molecular sieve catalyst, especially controlling the total acid amount and acid amount distribution, the method has higher isobutene yield for the skeletal isomerization reaction of the carbon tetraolefin, not only can reach the stable period of high isobutene yield in a short time, but also can maintain the stability for a longer time of more than 1300 hours.

2. The catalyst of the invention is prepared by synchronously preparing and shaping ZSM-35 molecular sieve, and then carrying out steam treatment under specific conditions to obtain the non-binder ZSM-35 molecular sieve catalyst. The preparation method of the catalyst disclosed by the invention is simple, seed crystals are not needed, pollution of waste acid, waste alkali and the like is reduced, the preparation method has obvious cost advantages and environmental protection advantages, and the obtained catalyst has good isomerization activity and good stability.

Drawings

FIG. 1 is an XRD spectrum of catalyst intermediates Z-1 to Z-6 obtained in examples 1 to 6;

FIG. 2 is an SEM photograph of the catalyst intermediate Z-1 obtained in example 1;

FIG. 3 is an SEM photograph of the catalyst intermediate Z-2 obtained in example 2;

FIG. 4 is an SEM photograph of the catalyst intermediate Z-3 obtained in example 3;

FIG. 5 is an SEM photograph of a catalyst intermediate Z-4 obtained in example 4;

FIG. 6 is an SEM photograph of a catalyst intermediate Z-5 obtained in example 5;

FIG. 7 is an SEM photograph of a catalyst intermediate Z-6 obtained in example 6;

FIG. 8 is NH of catalyst intermediates Z-1 to Z-6 obtained in examples 1 to 6 ₃ -TPD profile;

FIG. 9 is a schematic representation of NH of catalyst Z-1-7 from example 7, catalyst Z-1-12 from example 12, catalyst Z-2-20 from example 20, and catalyst Z-1-C1 from comparative example 1, catalyst Z-1-C3 from comparative example 3 ₃ -TPD profile;

FIG. 10 is a graph showing the results of evaluation of the long-period performance of the catalyst of example 18.

Detailed Description

The present invention will be described in detail with reference to examples, but the examples do not limit the scope of the present invention.

In the present invention, specific surface area, pore volume and pore size were measured on an automatic adsorption apparatus of Tristar-3000 type manufactured by Micromeritics, usa. The sample was degassed at 350℃for 2 hours under vacuum, and then the specific surface area of the sample was tested by nitrogen adsorption capacity method in liquid nitrogen (-196 ℃) and the result was calculated by BET method. The pore size and pore volume are calculated from the BJH formula.

In the invention, XRD test adopts a D8 advanced type polycrystalline powder diffractometer manufactured by Bruker company, germany, cu K

The tube voltage is 40kV, the tube current is 40mA, the scanning range 2 theta is 5-85 degrees, and the step size is 0.02 degrees.

In the characterization means of the catalyst without the binder, XRD is used for testing the phase contained and the content of each phase, and a scanning electron microscope is used for observing the situation of binder crystal transformation and the morphology of the generated molecular sieve. In the invention, when the binder adopted in the preparation of the catalyst is silica sol, the prepared binder-free catalyst does not contain amorphous silica.

In the invention, the analysis of the surface morphology of the catalyst is mainly completed by a Scanning Electron Microscope (SEM). The instrument used for SEM testing was the Nova NanoSEM 450 instrument from FEI company, usa.

In the invention, the Si/Al ratio element analysis is determined by an X-ray fluorescence spectrometer (XRF), the used instrument is a Bruce S4 Pioneer type analyzer in Germany, and the sample is prepared by adopting a tabletting mode.

In the present invention, ²⁷ al NMR is measured by a VNMR 400 instrument of Agilent company, signals of skeleton aluminum and non-skeleton aluminum species in a sample can be obtained through a small-plate chamfering single-pulse solid nuclear magnetic aluminum spectrum, wherein a spectrum peak near 55ppm is skeleton aluminum, spectrum peaks at other high-field chemical shift positions are non-skeleton aluminum, and the proportion composition of the skeleton aluminum and the non-skeleton aluminum is obtained through peak-division fitting integral calculation.

In the invention, the intensity is measured by using a DLIII intelligent particle intensity measuring instrument of the Ministry of technology development of Dacron Lian Peng.

In the invention, NH is used ₃ The surface acidity of the catalyst is measured for the probe molecules, and ammonia gas is subjected to temperature programmed desorption (NH ₃ -TPD) experimental conditions are as follows: 150mg of fresh catalyst (sieved to 20-40 mesh) was taken into a U-shaped quartz tube filled with quartz wool, and the catalyst was warmed from room temperature to 550℃at a heating rate of 10℃per minute in an atmosphere of He, followed by purging for 1h. Cooling to room temperature, and introducing 10vol.% NH ₃ The ammonia helium mixture is adsorbed for 30min, and then is converted into He carrier gas to be purged for 1h at 100 ℃ until the baseline is flat. And finally, heating the ammonia gas from 100 ℃ to 620 ℃ at a heating rate of 10 ℃/min to perform programmed temperature desorption, and detecting the desorbed ammonia molecules by adopting a TCD detector. The total acid amount is calibrated by ammonia gas with standard content, and the total acid amount is the sum of the amount of medium strong acid and the amount of strong acid, wherein the medium strong acid refers to the acid with the desorption temperature less than 330 ℃, and the strong acid refers to the acid with the desorption temperature of 330-620 ℃.

In the examples and comparative examples of the present invention, the evaluation conditions of the catalyst were as follows: crushing and sieving the catalyst into particles with 20-40 meshes, mixing the raw materials of carbon four (the mass fraction of n-butene is 71%, the mass fraction of isobutene is 1%, and the rest is butane and a small amount of propane and propylene) after using ether, and reacting at the temperature of 330 ℃ under the pressure of 0.12MPa for 3.0h at the mass space velocity of the carbon four ^-1 The catalyst activity was evaluated using an adiabatic fixed bed reactor with a catalyst loading of 5 g.

In the invention, the isobutene yield is calculated as follows:

isobutene mass yield (wt%) = (isobutene mass in product-isobutene mass in feed)/normal butene mass in feed x 100%.

Example 1

Weighing silica Sol (SiO) as precursor of white carbon black, sodium aluminate, kaolin and adhesive ₂ 40% of mass concentration), sodium carbonate and sesbania powder (wherein, white carbon black is prepared by SiO ₂ Calculated as Al with respect to sodium aluminate and kaolin ₂ O ₃ Calculated by Na and calculated by Na carbonate ₂ The mole ratio of sodium aluminate to kaolin to sodium carbonate to white carbon black is 1Al ₂ O ₃ ：0.7Na ₂ O：15SiO ₂ Sodium aluminate and kaolin in Al ₂ O ₃ The molar ratio is 1:1, a step of; silica sol addition amount as SiO ₂ Counting white carbon black by SiO ₂ Calculated on sodium aluminate and kaolin as Al ₂ O ₃ 55% of total mass, and the addition of sesbania powder is white carbon black and SiO ₂ Calculated on sodium aluminate and kaolin as Al ₂ O ₃ 2% of the total mass), extruding, granulating, drying at 110 ℃ for 24h, and roasting at 550 ℃ for 6h to obtain the precursor. The precursor and dissolved sodium hydroxide and cyclohexylamine (C) ₆ H ₁₃ N) (the mass concentration of sodium hydroxide is 2.2%, the mass concentration of cyclohexylamine is 8.5%) (wherein the addition amount of cyclohexylamine is as follows in mol): 1Al ₂ O ₃ ：1.5C ₆ H ₁₃ N, sodium hydroxide with Na ₂ The addition amount of the O meter is calculated as follows: 1Al ₂ O ₃ ：0.45Na ₂ O), transferring the mixture into a hydrothermal synthesis reaction kettle, and crystallizing at a gradient temperature rise, namely, crystallizing for 24 hours at 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃ and 160 ℃ step by step. And washing with distilled water, drying at 110 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the binder-free ZSM-35 molecular sieve catalyst intermediate. 2kg of the catalyst intermediate was taken and added to 10L of a 10wt% aqueous solution of ammonium nitrate and stirred at 80℃for 2 hours. The above steps were repeated three times. Filtering, washing with distilled water, drying at 110 ℃ for 24h, and roasting at 550 ℃ for 6h to obtain the hydrogen-free ZSM-35 catalyst intermediate, which is marked as Z-1.

XRD pattern of catalyst intermediate Z-1 is shown in figure 1, and has obvious ZSM-35 characteristic peak, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-1 is 97%.

SEM photographs of catalyst intermediate Z-1 are shown in fig. 2, and it can be seen from fig. 2 that the catalyst intermediate Z-1 is substantially free of amorphous binder species.

Acid test of catalyst intermediate Z-1: the results are shown in FIG. 3 and Table 3.

The results of the performance evaluation of the catalyst intermediate Z-1 are shown in Table 5.

Example 2

Weighing silica Sol (SiO) as precursor of white carbon black, aluminum sulfate, kaolin and adhesive ₂ 40% of mass concentration), potassium carbonate and sesbania powder (wherein, white carbon black is prepared by SiO ₂ Calculated as Al with aluminum sulfate and kaolin ₂ O ₃ Counting potassium carbonate by K ₂ The mole ratio of aluminum sulfate to kaolin to potassium carbonate to white carbon black is 1Al ₂ O ₃ ：0.7K ₂ O：15SiO ₂ Aluminum sulfate and kaolin in Al ₂ O ₃ The molar ratio is 1:1, a step of; silica sol addition amount as SiO ₂ Counting white carbon black by SiO ₂ Calculated on aluminum sulfate and kaolin as Al ₂ O ₃ 55% of total mass, and the addition of sesbania powder is white carbon black and SiO ₂ Calculated on aluminum sulfate and kaolin as Al ₂ O ₃ 2% of the total mass), extruding, granulating, drying at 100 ℃ for 24h, and roasting at 500 ℃ for 6h to obtain the precursor. The precursor and the potassium hydroxide and the n-butylamine (C) ₄ H ₁₁ N) (mass concentration of potassium hydroxide is 3%, mass concentration of N-butylamine is 6.5%) is added (wherein, the addition amount of N-butylamine is as follows in mole): 1Al ₂ O ₃ ：1.5C ₄ H ₁₁ N, potassium hydroxide in K ₂ The addition amount of the O meter is calculated as follows: 1Al ₂ O ₃ ：0.45K ₂ O), transferring the mixture into a hydrothermal synthesis reaction kettle, and crystallizing at a gradient temperature, namely, crystallizing for 24 hours at 110 ℃, 130 ℃, 150 ℃, 160 ℃ and 170 ℃ step by step. And then washing with distilled water, drying at 100 ℃ for 24 hours, and roasting at 500 ℃ for 6 hours to obtain the binder-free ZSM-35 molecular sieve catalyst intermediate. 2kg of catalyst intermediate was taken and 15L 8 wt% was added% ammonium sulfate in aqueous solution, NH is performed ₄ ⁺ Ion exchange and stirring at 70℃for 3h. The above steps were repeated three times. Filtering, washing with distilled water, drying at 120 ℃ for 18h, and roasting at 600 ℃ for 4h to obtain the hydrogen-free ZSM-35 catalyst intermediate, which is marked as Z-2.

XRD pattern of catalyst intermediate Z-2 is shown in figure 1, and has obvious ZSM-35 characteristic peak, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-2 is 97%.

SEM photographs of catalyst intermediate Z-2 are shown in fig. 3, and it can be seen from fig. 3 that the amorphous binder species are substantially absent from catalyst intermediate Z-2.

The results of the acidity test of catalyst intermediate Z-2 are shown in FIG. 8 and Table 3.

The results of the performance evaluation of the catalyst intermediate Z-2 are shown in Table 5.

Example 3

Weighing silica Sol (SiO) as precursor of white carbon black, pseudo-boehmite, kaolin and adhesive ₂ 40% by mass concentration), sodium carbonate and methylcellulose (wherein white carbon black is formed by SiO ₂ Calculated, pseudo-boehmite and kaolin are mixed with Al ₂ O ₃ Calculated by Na and calculated by Na carbonate ₂ O is calculated, the mol ratio of pseudo-boehmite to kaolin to sodium carbonate to white carbon black is 1Al ₂ O ₃ ：0.7Na ₂ O：15SiO ₂ Pseudo-boehmite and kaolin are prepared with Al ₂ O ₃ The molar ratio is 1:1, a step of; silica sol addition amount as SiO ₂ Counting white carbon black by SiO ₂ Meter and simulate boehmite and kaolin in Al ₂ O ₃ The total mass is 55 percent, and the added amount of the methyl cellulose accounts for the SiO of the white carbon black ₂ Meter and simulate boehmite and kaolin in Al ₂ O ₃ 2% of the total mass), extruding, granulating, drying at 110 ℃ for 24h, and roasting at 550 ℃ for 6h to obtain the precursor. Precursor and sodium hydroxide and 1, 4-cyclohexanediamine (C) ₆ H ₁₄ N ₂ ) (wherein, the addition amount of 1, 4-cyclohexanediamine is as follows in terms of mole) of the aqueous solution of (the mass concentration of sodium hydroxide is 2.2%, the mass concentration of 1, 4-cyclohexanediamine is 5.5%): 1Al ₂ O ₃ ：0.83C ₆ H ₁₄ N ₂ Sodium hydroxide in Na ₂ The addition amount of the O meter is calculated as follows: 1Al ₂ O ₃ ：0.45Na ₂ O), transferring the mixture into a hydrothermal synthesis reaction kettle, and crystallizing at gradient temperature rise, namely crystallizing for 24 hours at 100 ℃, 120 ℃, 140 ℃, 160 ℃ and 170 ℃ step by step. And washing with distilled water, drying at 110 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the sodium type ZSM-35 molecular sieve catalyst intermediate without the binder. 2kg of catalyst intermediate was taken and added to 10L of an aqueous ammonium acetate solution having a concentration of 10wt% to conduct NH ₄ ⁺ Ion exchange and stirring at 50℃for 4h. The above steps were repeated three times. Filtering, washing with distilled water, drying at 110 ℃ for 24h, and roasting at 550 ℃ for 6h to obtain the hydrogen-free ZSM-35 catalyst intermediate, which is marked as Z-3.

XRD pattern of catalyst intermediate Z-3 is shown in figure 1, and has obvious ZSM-35 characteristic peak, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-3 is 98%.

SEM photographs of catalyst intermediate Z-3 are shown in fig. 4, and it can be seen from fig. 4 that the amorphous binder species are substantially absent from catalyst intermediate Z-3.

The results of the acidity test for catalyst intermediate Z-3 are shown in FIG. 8 and Table 3.

The results of the performance evaluation of the catalyst intermediate Z-3 are shown in Table 5.

Example 4

Weighing silica Sol (SiO) as precursor of white carbon black, sodium aluminate, kaolin and adhesive ₂ 40% by mass concentration), sodium carbonate and microcrystalline cellulose (wherein white carbon black is formed by SiO ₂ Calculated as Al with respect to sodium aluminate and kaolin ₂ O ₃ Calculated by Na and calculated by Na carbonate ₂ The mole ratio of sodium aluminate to kaolin to sodium carbonate to white carbon black is 1Al ₂ O ₃ ：0.7Na ₂ O：15SiO ₂ Sodium aluminate and kaolin in Al ₂ O ₃ The molar ratio is 1:1, a step of; silica sol addition amount as SiO ₂ Counting white carbon black by SiO ₂ Calculated on sodium aluminate and kaolin as Al ₂ O ₃ The total mass is 52 percent, and the addition amount of microcrystalline cellulose accounts for the white carbon black and SiO is used as the raw material ₂ Sum of sodium aluminate and highThe kaolin is prepared from Al ₂ O ₃ 2.5 percent of the total mass is calculated, the precursor is obtained after the extrusion molding, the pelleting and the baking are carried out at 110 ℃ for 24 hours and 550 ℃ for 6 hours. Precursor and dissolved sodium hydroxide and ethylenediamine (C) ₂ H ₈ N ₂ ) (the mass concentration of sodium hydroxide is 2.2%, and the mass concentration of ethylenediamine is 10%), wherein the amount of ethylenediamine added is as follows in terms of mole: 1Al ₂ O ₃ ：2.9C ₂ H ₈ N ₂ Sodium hydroxide in Na ₂ The addition amount of the O meter is calculated as follows: 1Al ₂ O ₃ ：0.45Na ₂ O), transferring the mixture into a hydrothermal synthesis reaction kettle, and crystallizing at gradient temperature rise, namely crystallizing for 20 hours at 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃ and 170 ℃ respectively. And then washing with distilled water, drying at 110 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the sodium type ZSM-35 molecular sieve catalyst intermediate without the binder. 2kg of the catalyst intermediate was taken and added to 10L of 15wt% aqueous ammonium nitrate solution to conduct NH ₄ ⁺ Ion exchange and stirring at 80℃for 2h. The above steps were repeated three times. Filtering, washing with distilled water, drying at 110 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the hydrogen-type ZSM-35 catalyst intermediate without the binder, which is denoted as Z-4.

XRD pattern of catalyst intermediate Z-4 is shown in figure 1, and has obvious ZSM-35 characteristic peak, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-4 is 96%.

SEM photographs of catalyst intermediate Z-4 are shown in fig. 5, and it can be seen from fig. 5 that the catalyst intermediate Z-4 is substantially free of amorphous binder species.

The results of the acidity test for catalyst intermediate Z-4 are shown in FIG. 8 and Table 3.

The results of the performance evaluation of the catalyst intermediate Z-4 are shown in Table 5.

Example 5

Weighing white carbon black, sodium aluminate, pseudo-boehmite and a precursor silica Sol (SiO) of a binder ₂ 40% of mass concentration), sodium carbonate and sesbania powder (wherein, white carbon black is prepared by SiO ₂ Calculated as Al with sodium aluminate and pseudo-boehmite ₂ O ₃ Calculated by Na and calculated by Na carbonate ₂ The mole ratio of the sodium aluminate to the pseudo-boehmite, the sodium carbonate and the white carbon black is 1Al ₂ O ₃ ：0.7Na ₂ O：15SiO ₂ Sodium aluminate and pseudo-boehmite in Al ₂ O ₃ The molar ratio is 1:1, a step of; silica sol addition amount as SiO ₂ Counting white carbon black by SiO ₂ Calculated and calculated on sodium aluminate and pseudo-boehmite as Al ₂ O ₃ 50% of total mass, the sesbania powder accounts for SiO as white carbon black ₂ Calculated and calculated on sodium aluminate and pseudo-boehmite as Al ₂ O ₃ 2.5 percent of the total mass is calculated, the mixture is cut into particles after extrusion molding, and then dried at 110 ℃ for 24 hours and baked at 550 ℃ for 6 hours to obtain a precursor mixture. Precursor mixture and dissolved sodium hydroxide and cyclohexylamine (C ₆ H ₁₃ N) (the mass concentration of sodium hydroxide is 1.8%, the mass concentration of cyclohexylamine is 8.5%) (wherein the addition amount of cyclohexylamine is as follows in mol): 1Al ₂ O ₃ ：1.5C ₆ H ₁₃ N, sodium hydroxide with Na ₂ The addition amount of the O meter is calculated as follows: 1Al ₂ O ₃ ：0.40Na ₂ O), transferring the mixture into a hydrothermal synthesis reaction kettle, and crystallizing at gradient temperature rise, namely, crystallizing for 24 hours at 120 ℃, 130 ℃, 140 ℃, 150 ℃ and 160 ℃ respectively. And then washing with distilled water, drying at 110 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the sodium type ZSM-35 molecular sieve catalyst intermediate without the binder. 2kg of the catalyst intermediate was taken and added to 10L of 15wt% aqueous ammonium acetate and stirred at 40℃for 2 hours. The above steps were repeated three times. Filtering, washing with distilled water, drying at 110 ℃ for 24h, and roasting at 550 ℃ for 6h to obtain the hydrogen-free ZSM-35 catalyst intermediate, which is marked as Z-5.

XRD pattern of catalyst intermediate Z-5 is shown in figure 1, and has obvious ZSM-35 characteristic peak, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-5 is 96%.

SEM photographs of catalyst intermediate Z-5 are shown in fig. 6, and it can be seen from fig. 6 that the amorphous binder species are substantially absent from catalyst intermediate Z-5.

The results of the acidity test of catalyst intermediate Z-5 are shown in FIG. 8 and Table 3.

The results of the performance evaluation of the catalyst intermediate Z-5 are shown in Table 5.

Example 6

Weighing silica Sol (SiO) as precursor of white carbon black, sodium aluminate, kaolin and adhesive ₂ 40% by mass concentration), sodium carbonate and methylcellulose (wherein white carbon black is formed by SiO ₂ Calculated as Al with respect to sodium aluminate and kaolin ₂ O ₃ Calculated by Na and calculated by Na carbonate ₂ The mole ratio of sodium aluminate to kaolin to sodium carbonate to white carbon black is 1Al ₂ O ₃ ：0.7Na ₂ O：15SiO ₂ Sodium aluminate and kaolin in Al ₂ O ₃ The molar ratio is 1:1, a step of; silica sol addition amount as SiO ₂ Counting white carbon black by SiO ₂ Calculated on sodium aluminate and kaolin as Al ₂ O ₃ 50% of total mass, the sesbania powder accounts for SiO as white carbon black ₂ Calculated on sodium aluminate and kaolin as Al ₂ O ₃ 2.5 percent of the total mass is calculated, the precursor is obtained after the extrusion molding, the pelleting and the baking are carried out at 110 ℃ for 24 hours and 550 ℃ for 6 hours. The precursor and sodium hydroxide and n-butylamine (C) ₄ H ₁₁ N) (the mass concentration of sodium hydroxide is 1.8%, the mass concentration of N-butylamine is 6.5%) (wherein, the addition amount of N-butylamine is as follows in mol): 1Al ₂ O ₃ ：1.5C ₄ H ₁₁ N, sodium hydroxide with Na ₂ The addition amount of the O meter is calculated as follows: 1Al ₂ O ₃ ：0.40Na ₂ O), transferring the mixture into a hydrothermal synthesis reaction kettle, and crystallizing at a gradient temperature rise, namely, crystallizing for 24 hours at 110 ℃, 125 ℃, 140 ℃, 155 ℃, 170 ℃ and 185 ℃ respectively. And then washing with distilled water, drying at 110 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the sodium type ZSM-35 molecular sieve catalyst intermediate without the binder. 2kg of the catalyst intermediate was taken and added to 10L of 15wt% aqueous ammonium sulfate solution and stirred at 80℃for 2 hours. The above steps were repeated three times. Filtering, washing with distilled water, drying at 110 ℃ for 24h, and roasting at 550 ℃ for 6h to obtain the hydrogen-free ZSM-35 catalyst intermediate, which is marked as Z-6.

XRD pattern of catalyst intermediate Z-6 is shown in figure 1, and has obvious ZSM-35 characteristic peak, and the mass content of ZSM-35 molecular sieve in catalyst intermediate Z-6 is 97%.

SEM photographs of catalyst intermediate Z-6 are shown in fig. 7, and it can be seen from fig. 7 that the amorphous binder species are substantially absent from catalyst intermediate Z-6.

The results of the acidity test of catalyst intermediate Z-6 are shown in FIG. 8 and Table 3.

The results of the performance evaluation of the catalyst intermediate Z-6 are shown in Table 4.

Example 7

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at the temperature of 450 ℃ and the water vapor mass space velocity of 1.5h under the conditions of the rotating speed of 5rpm and the pressure of 0.3MPa ^-1 And (3) carrying out steam treatment on the catalyst for 8 hours under the condition of stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-7.

The results of the acidity test for catalysts Z-1-7 are shown in FIG. 9 and Table 3.

The results of the performance evaluation of the catalysts Z-1-7 are shown in Table 5.

Example 8

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at 475 ℃ and the water vapor mass space velocity is 1.5h under the conditions of the rotating speed of 5rpm, the pressure of 0.2MPa and the temperature of 475 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 6.5 hours under the condition of stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-8.

The results of the acidity test for catalysts Z-1-8 are shown in Table 3.

The results of the performance evaluation of catalysts Z-1-8 are shown in Table 5.

Example 9

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at the temperature of 500 ℃ and the water vapor mass space velocity of 1.5h under the conditions of the rotating speed of 4rpm, the pressure of 0.2MPa and the temperature of 500 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 5.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-9.

The results of the acid test of catalysts Z-1-9 are shown in Table 3.

The results of the performance evaluation of catalysts Z-1-9 are shown in Table 5.

Example 10

40 is taken0g of catalyst intermediate Z-1 is placed in a rotary tube furnace, and the rotating speed is 3rpm, the pressure is 0.1MPa, the temperature is 525 ℃ and the water vapor mass airspeed is 1.5h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-10.

The results of the acid test of catalysts Z-1-10 are shown in Table 3.

The results of the performance evaluation of catalysts Z-1-10 are shown in Table 5.

Example 11

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst is heated at the temperature of 550 ℃ and the steam mass space velocity of 1.5h under the conditions of the rotating speed of 3rpm, the pressure of 0.1MPa ^-1 And (3) carrying out steam treatment on the catalyst for 3.5 hours under the condition of stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-11.

The results of the acid test of catalysts Z-1-11 are shown in Table 3.

The results of the performance evaluation of catalysts Z-1-11 are shown in Table 5.

Example 12

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at the temperature of 575 ℃ and the water vapor mass space velocity for 1.5h under the conditions of the rotating speed of 2rpm, the pressure of normal pressure and the temperature of 575 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 3.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-12.

The results of the acidity test for catalysts Z-1-12 are shown in FIG. 9 and Table 3.

The results of the performance evaluation of catalysts Z-1-12 are shown in Table 5.

Example 13

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at the temperature of 600 ℃ and the water vapor mass space velocity for 1.5h under the conditions of the rotating speed of 2rpm, the pressure of normal pressure and the temperature of 600 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 2.5 hours under the condition of stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-13.

The results of the acidity test for catalysts Z-1-13 are shown in Table 3.

The results of the performance evaluation of catalysts Z-1-13 are shown in Table 5.

Example 14

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at 625 ℃ under the conditions of 2rpm, normal pressure and 625 ℃ and the water vapor mass space velocity is 1.5h ^-1 And (3) carrying out steam treatment on the catalyst for 2.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-14.

The results of the acidity test for catalysts Z-1-14 are shown in Table 3.

The results of the performance evaluation of catalysts Z-1-14 are shown in Table 5.

Example 15

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-2 is heated at 515 ℃ under the conditions of the rotating speed of 1rpm, the pressure of 0.1MPa and the water vapor mass space velocity of 0.5h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-15.

The results of the acidity test for catalyst Z-2-15 are shown in Table 3.

The results of the performance evaluation of the catalyst Z-2-15 are shown in Table 5.

Example 16

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-2 is heated at 515 ℃ under the conditions of the rotating speed of 1rpm, the pressure of 0.1MPa and the water vapor mass space velocity of 0.6h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-16.

The results of the acidity test for catalysts Z-2-16 are shown in Table 3.

The results of the performance evaluation of the catalysts Z-2-16 are shown in Table 5.

Example 17

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-2 is heated at 515 ℃ under the conditions of the rotating speed of 1rpm, the pressure of 0.1MPa and the water vapor mass space velocity of 1.0h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-17.

The results of the acidity test for catalyst Z-2-17 are shown in Table 3.

The results of the performance evaluation of the catalyst Z-2-17 are shown in Table 5.

Example 18

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst is heated at 515 ℃ under the conditions of the rotating speed of 1rpm, the pressure of 0.1MPa and the water vapor mass space velocity of 1.2h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-18.

The results of the acidity test for catalyst Z-2-18 are shown in Table 3.

The results of the performance evaluation of the catalysts Z-2-18 are shown in Table 5.

The long cycle performance of the Z-2-18 catalyst was evaluated and the results are shown in FIG. 10. As can be seen from fig. 10: the catalyst runs stably for more than 56d at the reaction temperature of 330-345 ℃, the single-pass average yield of isobutene is 39.2%, and the catalyst has good stability.

Example 19

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst is heated at 515 ℃ under the conditions of the rotating speed of 1rpm, the pressure of 0.1MPa and the water vapor mass space velocity of 1.5h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-19.

The results of the acid test of catalyst Z-2-19 are shown in Table 3.

The results of the performance evaluation of the catalysts Z-2-19 are shown in Table 5.

Example 20

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-2 is heated at 515 ℃ under the conditions of the rotating speed of 1rpm, the pressure of 0.1MPa and the water vapor mass space velocity of 2.3h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-20.

The results of the acidity test for catalyst Z-2-20 are shown in FIG. 9 and Table 3.

The results of the performance evaluation of the catalyst Z-2-20 are shown in Table 5.

Example 21

400g of catalyst intermediate Z-2 was taken and placed in a rotary reactorIn the tube furnace, the water vapor mass space velocity is 3.0h at the rotating speed of 1rpm, the pressure of 0.1MPa and the temperature of 515 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-21.

The results of the acidity test for catalyst Z-2-21 are shown in Table 3.

The results of the performance evaluation of the catalyst Z-2-21 are shown in Table 5.

Example 22

400g of catalyst intermediate Z-3 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-3 is heated at the temperature of 520 ℃ and the water vapor mass space velocity for 1.0h under the conditions of the rotating speed of 2rpm, the pressure of normal pressure and the temperature of 520 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-3-22.

The results of the acidity test for catalyst Z-3-22 are shown in Table 3.

The results of the performance evaluation of the catalyst Z-3-22 are shown in Table 5.

Example 23

400g of catalyst intermediate Z-4 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-4 is heated at the temperature of 530 ℃ and the water vapor mass space velocity of 1.2h under the conditions of the rotating speed of 1rpm and the pressure of 0.05MPa ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-4-23.

The results of the acid test of catalyst Z-4-23 are shown in Table 3.

The results of the performance evaluation of the catalyst Z-4-23 are shown in Table 5.

Example 24

400g of catalyst intermediate Z-5 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-5 is heated to 580 ℃ at a rotating speed of 1rpm and a pressure of normal pressure for 2.0h at a water vapor mass space velocity ^-1 And (3) carrying out steam treatment on the catalyst for 3.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-5-24.

The results of the acidity test for catalyst Z-5-24 are shown in Table 3.

The results of the performance evaluation of the catalysts Z-5-24 are shown in Table 5.

Example 25

400g of catalyst intermediate Z-6 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-6 is heated at the temperature of 500 ℃ and the steam mass space velocity of 1.0h under the conditions of the rotating speed of 2rpm and the pressure of 0.1MPa ^-1 And (3) carrying out steam treatment on the catalyst for 5.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-6-25.

The results of the acid test of catalyst Z-6-25 are shown in Table 3.

The results of the performance evaluation of the catalyst Z-6-25 are shown in Table 5.

Comparative example 1

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, the catalyst is subjected to steam treatment for 3.0h under the conditions of 2rpm, normal pressure, 575 ℃ and 0 steam mass airspeed, heating is stopped, nitrogen is switched, purging and cooling are carried out, and the catalyst is obtained and is marked as Z-1-C1.

The results of the acid test of catalysts Z-1-C1 are shown in FIG. 9 and Table 3.

The results of the performance evaluation of the catalysts Z-1 to C1 are shown in Table 5.

Comparative example 2

400g of catalyst intermediate Z-2 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-2 is heated at 515 ℃ under the conditions of the rotating speed of 0, the pressure of 0.1MPa and the water vapor mass airspeed of 0.5h ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-C2.

The results of the acid test of the catalyst Z-2-C2 are shown in Table 3.

The results of the catalyst Z-2-C2 performance evaluation are shown in Table 5.

Comparative example 3

400g of catalyst intermediate Z-1 is taken and placed in a rotary tube furnace, and the catalyst intermediate Z-1 is heated at the temperature of 350 ℃ and the water vapor mass space velocity for 1.5h under the conditions of the rotating speed of 2rpm, the pressure of normal pressure and the temperature of 350 DEG C ^-1 And (3) carrying out steam treatment on the catalyst for 3.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-1-C3.

The results of the acid test of catalysts Z-1 to C3 are shown in FIG. 9 and Table 3.

The results of the performance evaluation of the catalysts Z-1 to C3 are shown in Table 5.

Comparative example 4

400g of catalyst Z-2 is taken and placed in a rotary tube furnace, and the temperature is 515 ℃ and the water vapor mass space velocity is 0.20h at the rotating speed of 1rpm and the pressure of 0.1MPa ^-1 And (3) carrying out steam treatment on the catalyst for 4.0h, stopping heating, switching to nitrogen, purging and cooling to obtain the catalyst, which is marked as Z-2-C4.

The results of the acid test of the catalyst Z-2-C4 are shown in Table 3.

The results of the catalyst Z-2-C4 performance evaluation are shown in Table 5.

Table 1 properties of the catalysts obtained in each example

TABLE 2 radial crush strength of the catalysts obtained for each example

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TABLE 3 acidity of the catalysts obtained in each example

TABLE 4 composition of framework aluminum and non-framework aluminum in the catalyst structures obtained in each case

Table 5 evaluation results of the Activity of the catalysts obtained in each example

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As can be seen from Table 5, the catalyst of the present invention is used in the skeletal isomerization reaction of carbon tetraolefins, and can improve the yield of isobutene, and the stability of the catalyst is obviously enhanced.

Claims

1. The non-binder ZSM-35 molecular sieve catalyst is characterized in that the content of skeleton aluminum is 58% -82%, preferably 65% -80% and the content of non-skeleton aluminum is 18% -42%, preferably 20% -35% based on the weight of aluminum in the catalyst.

2. The catalyst according to claim 1, wherein the total acid content of the catalyst is 0.40 to 0.70 mmol.g ^-1 Preferably 0.45 to 0.70 mmol.g ^-1 ；

And/or, in the catalyst, the content of the medium strong acid is 55-75%, and the content of the strong acid is 25-45%; preferably, the content of the medium strong acid is 60% -70%, and the content of the strong acid is 30% -40%.

3. The catalyst according to claim 1, wherein the specific surface area of the catalyst is 250 to 350m ² ·g ^-1 Preferably 270 to 320m ² ·g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the Pore volume of 0.1 to the whole0.3cm ³ ·g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The average pore diameter is 2.0-5.0 nm.

4. The catalyst according to claim 1, wherein the catalyst has a SiO ₂ /Al ₂ O ₃ The molar ratio is 10 to 30, preferably 15 to 25.

5. The catalyst of claim 1, wherein the catalyst has a radial crush strength of from 4 to 10 n.mm ^-1 Preferably 5 to 8 N.multidot.mm ^-1 。

6. A preparation method of a non-binder ZSM-35 molecular sieve catalyst comprises the following steps:

7. The method of claim 6, wherein in step a) the silicon source is white carbon black; the aluminum source is one or more of sodium aluminate, aluminum sulfate, kaolin and pseudo-boehmite; the first alkali source is one or more of sodium carbonate and potassium carbonate; the binder is amorphous silica, and the binder precursor is silica sol; the auxiliary agent is one or more of sesbania powder, cellulose and starch;

and/or, the second alkali source in the step b) is one or more of sodium hydroxide and potassium hydroxide; the template agent is one or more of cyclohexylamine, n-butylamine, 1, 4-cyclohexanediamine and ethylenediamine;

and/or, in the solution containing the second alkali source and the template agent in the step b), the mass concentration of the second alkali source is 1-3%, and the mass concentration of the template agent is 3-15%.

8. The method of claim 6, wherein the first drying conditions of step a) are as follows: the first drying temperature is 80-200 ℃, the first drying time is 12-48 h, and the first roasting condition is as follows: the first roasting temperature is 400-600 ℃, and the first roasting time is 3-12 h;

and/or, the second drying conditions in step b) are as follows: the drying temperature is 80-120 ℃, the drying time is 12-48 h, and the second roasting condition is as follows: roasting temperature is 400-600 ℃, and roasting time is 3-12 h.

9. The process according to claim 6, wherein in step a) a silicon source, an aluminum source, a first alkali source, a binder precursor and an auxiliary agent are mixed, wherein the silicon source is SiO ₂ The aluminum source is Al ₂ O ₃ Calculated as oxide M from a first alkali source ₂ The material ratios of the silicon source, the aluminum source and the first alkali source are as follows: siO (SiO) ₂ With Al ₂ O ₃ The molar ratio of (2) is 10-20: 1, M ₂ O and Al ₂ O ₃ The molar ratio of (2) is 0.4-1.0: 1, a step of; the usage amount of the binder precursor is calculated by the binder and is calculated by the silicon source and the SiO ₂ Meter and aluminum source in Al ₂ O ₃ 40-60% of total mass, and the dosage of the auxiliary agent is silicon source and SiO ₂ Meter and aluminum source in Al ₂ O ₃ 1 to 5 percent of the total mass;

and/or, step b) mixing a solution containing a second source of alkalinity and a templating agent with the precursor obtained in step a), the second source of alkalinity being present as the oxide M in the resulting mixture ₂ O meter, step a) aluminum source is calculated as Al ₂ O ₃ The calculated molar ratio is 0.30-0.6: 1, a step of; template agent and step a) aluminum source are prepared by using Al ₂ O ₃ The molar ratio is 1-6: 1.

10. the preparation method according to claim 6, wherein the hydrothermal crystallization in step b) adopts gradient heating crystallization, the initial temperature is 80-140 ℃, the end temperature is 150-200 ℃, and the total crystallization time is 48-192 h; wherein, the gradient heating crystallization adopts at least 2 gradients, further 2-10 gradients, and the temperature difference between two adjacent gradients is at least 5 ℃ or more, further 10 ℃ or more, and preferably 10-30 ℃.

11. The process according to claim 6, wherein the steam treatment in step c) is carried out in a rotary tube furnace (preferably, the rotation speed is not less than 1rpm, more preferably 1 to 5 rpm); the conditions for the steam treatment in step c) are as follows: the mass airspeed of the water vapor is 0.3 to 5 hours ^-1 Preferably 0.5 to 3.0h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The treatment temperature is 400-700 ℃, preferably 450-600 ℃; the treatment pressure is 0-1 MPa, preferably 0-0.5 MPa; the treatment time is 1 to 10 hours, preferably 3 to 8 hours.

12. Use of the catalyst of any one of claims 1 to 5 or the catalyst prepared by the preparation method of any one of claims 6 to 11 in a skeletal isomerization reaction of a carbon tetraolefin.

13. Use according to claim 12, wherein the carbon tetraolefin is n-butene or a mixed hydrocarbon containing n-butene; and/or the temperature of the reaction is 200-500 ℃, preferably 300-450 ℃; and/or the pressure of the reaction is 0 to 1MPa, preferably 0 to 0.5MPa, more preferably 0 to 0.2MP; and/or the mass space velocity of the carbon tetraolefin is 0.1-10 h ^-1 Preferably 0.5 to 6 hours ^-1 。