Preparation method of bax-ZSM-5 membrane / coal gangue catalyst

Abstract

A preparation method of a bax-ZSM-5 membrane / coal gangue catalyst belongs to the technical field of catalysts, and comprises the following three key steps: preparation of a flaky coal gangue carrier material, synthesis of bax-ZSM-5 seed crystal / coal gangue, and hydrothermal preparation of the bax-ZSM-5 membrane / coal gangue catalyst. The coal gangue carrier can form a porous structure after deliming, desulfurization and pore forming, and can form a quartz crystal phase after calcination, so that b-axis orientation pre-planting of ZSM-5 crystal seeds is promoted; the prepared bax-ZSM-5 membrane / coal gangue catalyst has highly unified b-axis orientation, and compared with a traditional ZSM-5 molecular sieve, the bax-ZSM-5 membrane / coal gangue catalyst can promote methanol and an intermediate product to be diffused more quickly, and the methanol conversion rate and the target product selectivity are further improved in an MTA reaction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalysts, and particularly relates to a preparation method of a methanol-to-aromatics catalyst. BACKGROUND

[0002] Light aromatic hydrocarbons such as benzene (B), toluene (T), xylene (X) and the like are important raw materials for organic chemicals and polymer industries and are widely used. Methanol-to-aromatics (MTA), especially light aromatic hydrocarbons such as BTX, is a strategic process technology, which is of great significance for realizing low-cost synthesis of high-quality aromatic hydrocarbons through a non-petroleum route and expanding the application of methanol. ZSM-5 molecular sieves are widely used in the methanol-to-aromatics reaction due to their high stability, high specific surface area and shape-selective catalytic function, which is conducive to improving the selectivity of aromatic hydrocarbons. In particular, the straight channel structure of the b-axis of ZSM-5 molecular sieves can enable methanol molecules to rapidly diffuse in the one-dimensional straight channel, shorten the molecular diffusion path, and thus reduce the possibility of deep product side reactions and inhibit the formation of coke. Therefore, the b-oriented ZSM-5 molecular sieves have more advantages than randomly oriented molecular sieves.

[0003] Coal gangue, as one of the solid waste materials, has a low comprehensive utilization rate. It is gradually developed and applied in the preparation of molecular sieve materials due to the fact that it contains a large amount of SiO2 and Al2O3 and the like. A common method is to use the silicon and aluminum sources in the coal gangue as a precursor solution of the molecular sieve. Although ZSM-5 molecular sieves can be prepared by this method, filter residue is generated during the preparation process due to the treatment of the coal gangue. In addition, the molecular sieves prepared by these methods do not have a unified b-axis orientation, and thus the role of the b-axis channel cannot be better played. SUMMARY

[0004] To solve the above technical problems, the application provides a preparation method of a b-axis-ZSM-5 membrane / coal gangue catalyst to improve the performance of ZSM-5 molecular sieves in the methanol-to-aromatics reaction.

[0005] To achieve the above object, the technical scheme adopted by the application is as follows: a preparation method of a b-axis-ZSM-5 membrane / coal gangue catalyst, comprising the following steps:

[0006] Preparation of a flaky coal gangue carrier material: coal gangue powder is sequentially subjected to a first acidic deashing treatment and an oxidant desulfurization treatment, and then sequentially subjected to filtration, washing, drying, calcination and a second acidic deashing and drying to obtain a coal gangue pretreated powder; the coal gangue pretreated powder and a pore-forming agent are mixed, and then subjected to tabletting and calcination to obtain a flaky coal gangue carrier material CG.

[0007] b-axis-ZSM-5 seed / coal gangue synthesis: mixing tetrapropylammonium hydroxide, water and tetraethyl orthosilicate and aging; placing flaky coal gangue carrier material CG vertically at the bottom of the aged solution, then sequentially going through crystallization, washing, drying and calcination to obtain b-axis-ZSM-5 seed / coal gangue b-ZSM-5 seed / CG seed / CG;

[0008] b-axis-ZSM-5 membrane / coal gangue catalyst hydrothermal preparation: mixing tetrapropylammonium hydroxide, tetraethyl orthosilicate, water and sodium aluminate and aging to obtain a mixed solution; placing b-axis-ZSM-5 seed / coal gangue b-ZSM-5 seed / CG at the bottom of the mixed solution, and then washing and drying after hydrothermal treatment to obtain b-axis-ZSM-5 membrane / coal gangue catalyst b-ZSM-5 / CG.

[0009] Preferably, in the preparation of the flaky coal gangue carrier material, the coal gangue powder comprises: 45%-55% of silicon oxide, 20%-30% of aluminum oxide, and 1.5%-2.5% of titanium dioxide;

[0010] The particle size of the coal gangue powder is 150-200 mesh;

[0011] Preferably, in the preparation of the flaky coal gangue carrier material, the mixed acid used in the first and second acid deashing is prepared by mixing 15% HCl and 25% H2SO4 in a volume ratio of 1:(0.5-1.5);

[0012] The mass ratio of the coal gangue powder and the mixed acid is 1:(5-10), and the treatment temperature of the first and second acid deashing is 40-50°C, and the treatment time is 5-6h.

[0013] Preferably, in the desulfurization treatment with the oxidant, the oxidant is potassium permanganate solution with a concentration of 0.05mol / L-0.1mol / L, the mass ratio of the coal gangue powder and the oxidant is 1:(5-10), the oxidation time is 15min-20min, and the oxidation temperature is 363K-383K.

[0014] Preferably, the calcination temperature between the first and second acid deashing treatments is 873K-1123K, and the calcination time is 2h-3h.

[0015] Preferably, the mixed mass ratio of the coal gangue pretreated powder and the pore-forming agent is 1:(0-0.1), and the pore-forming agent is ammonium bicarbonate;

[0016] In the tabletting forming in the preparation of the flaky coal gangue carrier material, the forming pressure is 0.8MPa-1.2MPa, and the pressure holding time is 60s-80s.

[0017] Preferably, the molar ratio of tetrapropylammonium hydroxide, water and tetraethyl orthosilicate in the b-axis-ZSM-5 seed / coal gangue synthesis is (0.25-0.35):165:1; the aging temperature is 25-35℃, and the aging time is 20-24h.

[0018] Preferably, in the b-axis-ZSM-5 seed / coal gangue synthesis, the flaky coal gangue carrier material CG is crystallized in the mixed solution at a temperature of 430-470K for 70-90min, and the dried calcination temperature is 823K, and the calcination time is 2h.

[0019] Preferably, in the b-axis-ZSM-5 membrane / coal gangue catalyst hydrothermal preparation, the molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, water and sodium aluminate is (0.25-0.35):1:165:0.005, the aging temperature is 70-90℃, and the aging time is 2-3h.

[0020] Preferably, in the b-axis-ZSM-5 membrane / coal gangue catalyst hydrothermal preparation, the b-axis-ZSM-5 seed / coal gangue b-ZSM-5 seed / CG is hydrothermally treated at the bottom of the mixed solution at a temperature of 400-440K for 23-25h.

[0021] Compared with the prior art, the application has the following beneficial effects:

[0022] The application can significantly enhance the diffusion rate of methanol molecules and intermediates in the ZSM-5 channel, improve the transfer efficiency of target products in the coal gangue base, and improve the performance of ZSM-5 molecular sieve in the methanol-to-aromatics process. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments are described below in detail. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope.

[0024] The application provides a preparation method of a b-axis-ZSM-5 membrane / coal gangue catalyst, which comprises the following steps:

[0025] The flaky coal gangue carrier material is prepared as follows: the coal gangue powder is sequentially subjected to a primary acidic deashing treatment and an oxidant desulfurization treatment, and then is sequentially subjected to filtration, washing, drying, calcination and secondary acidic deashing and drying to obtain a coal gangue pretreated powder; the coal gangue pretreated powder and a pore-forming agent are mixed, and then are subjected to tabletting and calcination to obtain the flaky coal gangue carrier material CG.

[0026] b-axis-ZSM-5 seed / coal gangue synthesis: mixing tetrapropylammonium hydroxide, water and tetraethyl orthosilicate and aging; placing flaky coal gangue carrier material CG vertically at the bottom of the aged solution, then sequentially going through crystallization, washing, drying and calcination to obtain b-axis-ZSM-5 seed / coal gangue b-ZSM-5 / CG. seed

[0027] b-axis-ZSM-5 membrane / coal gangue catalyst hydrothermal preparation: mixing tetrapropylammonium hydroxide, tetraethyl orthosilicate, water and sodium aluminate and aging to obtain a mixed solution; placing b-axis-ZSM-5 seed / coal gangue b-ZSM-5 / CG at the bottom of the mixed solution, and after hydrothermal treatment, washing and drying to obtain b-axis-ZSM-5 membrane / coal gangue catalyst b-ZSM-5 / CG. seed

[0028] In a further embodiment of the present embodiment, in the preparation of the flaky coal gangue carrier material, the coal gangue powder comprises: 45%-55% of silicon oxide, 20%-30% of aluminum oxide, and 1.5%-2.5% of titanium dioxide;

[0029] The particle size of the coal gangue powder is 150-200 mesh;

[0030] In a further embodiment of the present embodiment, in the preparation of the flaky coal gangue carrier material, the mixed acid used for the first and second acid deashing is prepared by mixing 15% HCl and 25% H2SO4 in a volume ratio of 1:(0.5-1.5);

[0031] The mass ratio of the coal gangue powder and the mixed acid is 1:(5-10), and the treatment temperature of the first and second acid deashing is 40-50°C, and the treatment time is 5-6h.

[0032] In a further embodiment of the present embodiment, in the desulfurization treatment with the oxidant, the oxidant is potassium permanganate solution with a concentration of 0.05-0.1 mol / L, the mass ratio of the coal gangue powder and the oxidant is 1:(5-10), the oxidation time is 15-20 min, and the oxidation temperature is 363-383K.

[0033] In a further embodiment of the present embodiment, the calcination temperature between the first and second acid deashing treatments is 873-1123K, and the calcination time is 2-3h.

[0034] In a further embodiment of the present embodiment, the mixing mass ratio of the coal gangue pretreated powder and the pore-forming agent is 1:(0-0.1), and the pore-forming agent is ammonium bicarbonate;

[0035] ​​The forming pressure in the tabletting forming in the preparation of the flaky coal gangue carrier material is 0.8 MPa-1.2 MPa, and the pressure maintaining time is 60 s-80 s.

[0036] In a further implementation form of the present embodiment, in the b-axis ZSM-5 seed / coal gangue synthesis, the molar ratio of TPAOH, water and TEOS is (0.25-0.35):165:1; the aging temperature is 25℃-35℃, and the aging time is 20h-24h.

[0037] In a further implementation form of the present embodiment, in the b-axis ZSM-5 seed / coal gangue synthesis, the flaky coal gangue carrier material CG is crystallized in the mixed solution at a temperature of 430K-470K for 70min-90min, and the dried and calcined temperature is 823K, and the calcination time is 2h.

[0038] In a further implementation form of the present embodiment, in the b-axis ZSM-5 seed / coal gangue synthesis, the molar ratio of TPAOH, water and TEOS is (0.25-0.35):165:1; the aging temperature is 25℃-35℃, and the aging time is 20h-24h.

[0039] In a further implementation form of the present embodiment, in the b-axis ZSM-5 seed / coal gangue synthesis, the molar ratio of TPAOH, water and TEOS is (0.25-0.35):165:1; the aging temperature is 25℃-35℃, and the aging time is 20h-24h. seed / CG in the mixed solution is hydrothermally treated at a temperature of 400K-440K for 23h-25h.

[0040] It should be noted that the coal gangue carrier can form a porous structure after being deashed, desulfurized and pore-forming, and can form a quartz crystal phase after calcination, thereby promoting the b-axis orientation of the ZSM-5 seed; the prepared b-axis ZSM-5 membrane / coal gangue catalyst has a highly uniform b-axis orientation, compared with the traditional ZSM-5 molecular sieve, which can promote the rapid diffusion of methanol and intermediate products, and further improve the methanol conversion rate and the selectivity of the target product in the MTA reaction.

[0041] The present application will be further described in detail below with reference to specific examples, wherein TPAOH is tetrapropylammonium hydroxide, TEOS is tetraethyl orthosilicate, and MTA reaction is the chemical process of methanol to aromatics.

[0042] Example 1

[0043] The coal gangue from Zhouyuanshan coal mine was crushed by a crusher, and the powder was obtained by passing through a 200-mesh sieve. The sample was acid-treated with a mixed acid prepared by mixing 15% HCl and 25% H2SO4 at a volume ratio of 1:0.5, and the amount of mixed acid used was 5g for 1g of powder.

[0044] The mixed solution was continuously stirred at 40°C for 5h, and finally left at room temperature for 12h, and centrifuged and dried. Subsequently, the acid-treated coal gangue powder was placed in a 0.05 mol / L potassium permanganate solution at a temperature of 373K and stirred for 15 min, and the mass ratio of the coal gangue powder to the potassium permanganate solution was 1:5. Then, the sample was filtered, washed, and dried to obtain the acid-treated coal gangue H-CG1.

[0045] The H-CG1 was placed in a muffle furnace at 873K for calcination for 2h to obtain a quartz crystal phase. After the reaction was completed, the sample was left to cool at room temperature, and then the coal gangue powder was again subjected to acid treatment with a mixed acid prepared by mixing 15% HCl and 25% H2SO4 at a volume ratio of 1:0.5, and the amount of the mixed acid used was 5g for 1g of the powder.

[0046] The acid-treated coal gangue powder 10g was pressed into a tablet by a tablet press, and then calcined at 100°C for 30 min in a muffle furnace, and the pressing intensity of the tablet press was constant at 1 MPa and the pressing time was 1 min. Then, the coal gangue tablet was sequentially subjected to ultrasonic cleaning in acetone, anhydrous ethanol, and deionized water for 10 min, and then dried and placed in an oven at 373K for drying for 12h. The obtained solid sample was used as a base material CG1.

[0047] The TPAOH, water, and TEOS in a molar ratio of 0.25:165:1 were uniformly mixed and aged at 25°C for 24h. The base material CG1 was vertically placed at the bottom of a polytetrafluoroethylene liner, and the aged solution was poured into the liner, and the liner was placed in a crystallization kettle and sealed, and then crystallized in an oven at 430K for 70 min. Finally, the obtained sample was washed and dried, and then placed in a tube furnace and calcined at 823K for 2h to obtain a b-axis oriented ZSM-5 seed material b1-ZSM-5. seed / CG, and the heating and cooling rates were 0.5K / min.

[0048] The TPAOH, TEOS, water, and sodium metaaluminate in a molar ratio of 0.25:1:165:0.005 were uniformly mixed and aged at 70°C for 2h. The above b1-ZSM-5 seed / CG was placed in a hydrothermal kettle, and then the synthesis solution was poured into the kettle, and hydrothermal treatment was performed at 400K for 23h. After the treatment was completed, the sample was centrifuged, washed, and dried in an oven at 80°C for 24h to obtain a b1-ZSM-5 / CG molecular sieve membrane sample.

[0049] Table 1 is the ash analysis of coal gangue from Zhouyuanshan coal mine. As can be seen from Table 1, after calcination at 873 K, the coal gangue mainly becomes SiO2, showing quartz crystal phase, so that the ZSM-5 seed can be pre-planted on the surface of the coal gangue with b-axis orientation. Table 2 is the pore structure parameters of the coal gangue sheet CG and the prepared b1-ZSM-5 / CG sample. As can be seen from Table 2, the coal gangue sheet CG is mainly microporous, and after acid washing, the micropore specific surface area decreases, the volume also decreases, and the mesopore volume increases, indicating that acid washing produces more mesopores in the coal gangue, which is beneficial to the rapid transfer of reaction products. After the b-axis oriented ZSM-5 molecular sieve is loaded on the coal gangue carrier, the specific surface area of the mesopore increases, the pore volume becomes larger, while the specific surface area of the micropore decreases, and the pore volume becomes smaller, indicating that the number of micropores in the prepared ZSM-5 molecular sieve membrane sample decreases and the number of mesopores increases, which is not easy to block the pore channel, and is beneficial to the mass transfer of macromolecular substances. Table 3 is the data of methanol conversion rate and aromatic selectivity after 2h of reaction, which shows that compared with the conventional ZSM-5, the b-axis oriented ZSM-5 has higher conversion rate and aromatic selectivity in catalyzing methanol, indicating that the prepared b-axis-ZSM-5 membrane / coal gangue catalyst has more excellent performance.

[0050] Table 1 Ash analysis of coal gangue after calcination and activation (chemical composition / w%)

[0051]

[0052] Table 2 Pore structure parameters of ZSM-5 molecular sieve membrane

[0053]

[0054] Table 3 Catalytic performance of molecular sieve

[0055]

[0056] Example 2

[0057] The coal gangue from Xuzhou coal mine was crushed by a crusher and passed through a 200-mesh sieve to obtain a powder. The sample was acid treated with a mixed acid prepared by mixing 15% HCl and 25% H2SO4 at a volume ratio of 1:0.5, and the amount used was 5 g of mixed acid for 1 g of powder.

[0058] The mixed solution was continuously stirred at 40°C for 5h, and finally left at room temperature for 12h, and centrifuged and dried. Subsequently, the acid-treated coal gangue powder was placed in a 0.05 mol / L potassium permanganate solution at a temperature of 373 K and stirred for 15 min, and the mass ratio of coal gangue powder to potassium permanganate solution was 1:5. Then it was filtered, washed and dried to obtain the acid-treated coal gangue H-CG2.

[0059] H-CG2 was calcined in a muffle furnace at 873 K for 2 h to obtain quartz crystalline phase. After the reaction, the sample was cooled at room temperature and then the coal gangue powder was treated with a mixed acid of 15% HC1 and 25% H2SO4 with a volume ratio of 1:0.5, and the amount of the mixed acid was 5 g for 1 g of the powder.

[0060] The acid-treated coal gangue powder 10 g was pressed into a tablet by a tablet press, and then the tablet was calcined in a muffle furnace at 100 °C for 30 min, and the pressing intensity of the tablet press was 1 MPa and the pressing time was 1 min. Then the coal gangue tablet was sequentially cleaned with acetone, anhydrous ethanol and deionized water by ultrasonic cleaning for 10 min, and then dried in an oven at 373 K for 12 h. The obtained solid sample was used as the base material CG2.

[0061] TPAOH, water and TEOS with a molar ratio of 0.25:165:1 were uniformly mixed and aged at 25 °C for 24 h. The base material CG2 was vertically placed at the bottom of a polytetrafluoroethylene liner, and the aged solution was poured into the liner, and then the liner was placed in a crystallization kettle and sealed, and then crystallized in an oven at 430 K for 70 min. Finally, the obtained sample was washed and dried, and then calcined in a tube furnace at 823 K for 2 h to obtain the b-axis oriented ZSM-5 seed material b2-ZSM-5 / CG. seed / CG, and the heating and cooling rates were 0.5 K / min.

[0062] TPAOH, TEOS, water and sodium metaaluminate with a molar ratio of 0.25:1:165:0.005 were uniformly mixed and aged at 70 °C for 2 h. The above b2-ZSM-5 / CG was placed in a hydrothermal kettle, and then the synthesis solution was poured into the kettle, and then hydrothermally treated in an oven at 400 K for 23 h. After the treatment, the sample was centrifuged and washed, and then dried in an oven at 80 °C for 24 h to obtain the b2-ZSM-5 / CG molecular sieve membrane sample. seed / CG, and the heating and cooling rates were 0.5 K / min.

[0063] Table 4 Analysis of ash content of coal gangue after calcination and activation (chemical composition / w%)

[0064]

[0065] Table 5 Catalytic performance of molecular sieve

[0066]

[0067] Table 4 shows the ash analysis of coal gangue from the Xuzhou coal mine. As can be seen from Table 4, after calcination at 873K, the gangue primarily becomes SiO2, exhibiting a quartz phase. This allows for the pre-implantation of ZSM-5 seeds with a b-axis orientation on the gangue surface. Table 5 shows the methanol conversion and aromatics selectivity data 2 hours after the reaction. It can be seen that the b-axis-oriented ZSM-5 exhibits higher methanol conversion and aromatics selectivity than conventional ZSM-5, demonstrating the superior performance of the prepared b2-ZSM-5 / CG catalyst.

[0068] Example 3

[0069] Gangue from the Zhouyuanshan coal mine was crushed with a crusher and passed through a 200-mesh sieve to obtain a powder. The sample was then treated with a mixed acid of 15% HCl and 25% H2SO4 in a volume ratio of 1:0.5, using 5g of mixed acid per 1g of powder.

[0070] The mixture was stirred continuously at 40°C for 5 hours, then allowed to stand at room temperature for 12 hours, centrifuged, and dried. The acid-treated gangue powder was then placed in a 0.05 mol / L potassium permanganate solution at 373K and stirred for 15 minutes. The mass ratio of gangue powder to potassium permanganate solution was 1:5. The mixture was then filtered, washed, and dried to obtain the acid-treated gangue H-CG3.

[0071] H-CG3 was calcined in a muffle furnace at 973K for 2 hours to produce a quartz crystal phase. After the reaction, the sample was cooled to room temperature. The gangue powder was then treated again with a mixed acid solution of 15% HCl and 25% H2SO4 at a volume ratio of 1:0.5, using 5g of the mixed acid per 1g of powder.

[0072] Weigh 10g of acid-treated coal gangue powder and press it into tablets. The tablets were then calcined in a muffle furnace at 100°C for 30 minutes, maintaining a constant pressure of 1 MPa for 1 minute. The coal gangue tablets were then ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water for 10 minutes each. After drying, they were placed in an oven at 373K for 12 hours. The resulting solid sample served as the base material CG3.

[0073] TPAOH, water, and TEOS at a molar ratio of 0.25:165:1 were uniformly mixed and aged at 25°C for 24 hours. The matrix material CG3 was placed vertically at the bottom of the polytetrafluoroethylene liner, and the aged solution was poured into it. The liner was placed in a crystallization kettle and sealed, and then crystallized in a constant temperature box at 430K for 70 minutes. Finally, the obtained sample was washed and dried, and then calcined in a tube furnace at 823K for 2 hours to obtain the b-axis oriented ZSM-5 seed material b3-ZSM-5. seed / CG, the heating and cooling rates are 0.5 K / min.

[0074] TPAOH, TEOS, water, sodium metaaluminate in a molar ratio of 0.25:1:165:0.005 were mixed uniformly and aged at 70°C for 2h. The above b3-ZSM-5 / CG was placed in a hydrothermal kettle, then poured into the synthesis solution, and hydrothermally treated in a 400K oven for 23h. After the end of the reaction, centrifugal washing and drying in an oven at 80°C for 24h were performed to obtain a b3-ZSM-5 / CG molecular sieve membrane sample. seed / CG was placed in a hydrothermal kettle, then poured into the synthesis solution, and hydrothermally treated in a 400K oven for 23h. After the end of the reaction, centrifugal washing and drying in an oven at 80°C for 24h were performed to obtain a b3-ZSM-5 / CG molecular sieve membrane sample.

[0075] Table 6 Catalytic performance of the molecular sieve

[0076]

[0077] Table 6 is the methanol conversion rate and aromatic selectivity data 2h after the reaction, it can be seen that the b-axis oriented ZSM-5 has higher methanol conversion rate and aromatic selectivity than the conventional ZSM-5, which indicates that the prepared b3-ZSM-5 / CG has more excellent performance.

[0078] Example 4

[0079] The coal gangue from Zhouyuanshan coal mine was crushed by a crusher and sieved through a 200-mesh sieve to obtain a powder. The sample was acid-treated with a mixed acid prepared from 15% HCl and 25% H2SO4 in a volume ratio of 1:0.5, and the amount of the mixed acid was 5g for 1g of the powder.

[0080] The mixed solution was continuously stirred at 40°C for 5h, and finally left to stand at room temperature for 12h, and then centrifuged and dried. Subsequently, the acid-treated coal gangue powder was placed in a 0.05mol / L potassium permanganate solution at a temperature of 373K and stirred for 15min, and the mass ratio of the coal gangue powder to the potassium permanganate solution was 1:5. Then, the sample was filtered, washed, and dried to obtain the acid-treated coal gangue H-CG4.

[0081] The H-CG4 was placed in a muffle furnace and calcined at 873K for 2h to obtain a quartz crystal phase. After the reaction, the sample was left to cool at room temperature, and then the coal gangue powder was again acid-treated with a mixed acid prepared from 15% HCl and 25% H2SO4 in a volume ratio of 1:0.5, and the amount of the mixed acid was 5g for 1g of the powder.

[0082] A mass fraction of 5% pore-forming agent ammonium bicarbonate powder was added to the acid-treated coal gangue powder, and the mixture was uniformly mixed, 10g of which was pressed into a tablet by a tablet press, and then calcined at 100°C for 30min in a muffle furnace. The pressing intensity of the tablet press was constant at 1MPa, and the pressing time was 1min. The coal gangue tablet was sequentially ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water for 10min, and then dried and placed in an oven at 373K for 12h. The obtained solid sample was used as a substrate material CG4.

[0083] A mixture of TPAOH, water and TEOS in a molar ratio of 0.25:165:1 was mixed homogeneously and aged at 25°C for 24 h. The substrate CG4 was placed vertically at the bottom of a polytetrafluoroethylene liner, the aged solution was poured into the liner, which was then placed in a crystallization kettle and sealed, and then crystallized in an oven at 430 K for 70 min. Finally, the obtained sample was washed, dried and calcined in a tube furnace at 823 K for 2 h to obtain the b-axis oriented ZSM-5 seed material b4-ZSM-5 / CG. seed The temperature was raised and lowered at a rate of 0.5 K / min.

[0084] A mixture of TPAOH, TEOS, water and sodium aluminate in a molar ratio of 0.25:1:165:0.005 was mixed homogeneously and aged at 70°C for 2 h. The above b4-ZSM-5 / CG was placed in a hydrothermal kettle, and then the synthesis solution was poured into the kettle, which was then hydrothermally treated in an oven at 400 K for 23 h. After the end of the reaction, the sample was washed by centrifugation and dried in an oven at 80°C for 24 h to obtain the b4-ZSM-5 / CG molecular sieve membrane sample. seed The temperature was raised and lowered at a rate of 0.5 K / min.

[0085] Table 7 Catalytic performance of the molecular sieve

[0086]

[0087] Table 7 shows the methanol conversion and aromatic selectivity data 2 h after the reaction. It can be seen that the b-axis oriented ZSM-5 has higher methanol conversion and aromatic selectivity than the conventional ZSM-5, indicating that the prepared b4-ZSM-5 / CG has more excellent performance.

[0088] Example 5

[0089] The coal gangue from Zhouyuanshan coal mine was crushed by a crusher and passed through a 200-mesh sieve to obtain a powder. The sample was acid-treated with a mixed acid prepared from 15% HC1 and 25% H2SO4 in a volume ratio of 1:0.5, and the amount of the mixed acid was 5 g for 1 g of the powder.

[0090] The mixed solution was continuously stirred at 40°C for 5 h, and finally left to stand at room temperature for 12 h, and then centrifuged and dried. Subsequently, the acid-treated coal gangue powder was placed in a 0.05 mol / L potassium permanganate solution at a temperature of 373 K and stirred for 15 min, and the mass ratio of the coal gangue powder to the potassium permanganate solution was 1:5. Then, the sample was filtered, washed and dried to obtain the acid-treated coal gangue H-CG5.

[0091] The H-CG5 was calcined in a muffle furnace at 873 K for 2 h to obtain a quartz crystal phase. After the reaction, the sample was left to cool at room temperature, and then the coal gangue powder was again acid-treated with a mixed acid prepared from 15% HC1 and 25% H2SO4 in a volume ratio of 1:0.5, and the amount of the mixed acid was 5 g for 1 g of the powder.

[0092] To the acid treated coal gangue powder, 5% of pore forming agent ammonium bicarbonate powder was added, and after uniform mixing, 10 g was weighed and pressed into a tablet by a tablet press. The tablet was calcined at 100°C for 30 min in a muffle furnace. The pressing intensity of the tablet press was constant at 1 MPa, and the time was 1 min. Then the coal gangue tablet was sequentially placed in acetone, anhydrous ethanol and deionized water for ultrasonic cleaning for 10 min, and then dried in an oven at 373 K for 12 h. The obtained solid sample was used as the base material CG5.

[0093] The TPAOH, water and TEOS with a molar ratio of 0.30:165:1 were uniformly mixed and aged at 25°C for 24 h. The base material CG5 was vertically placed at the bottom of a polytetrafluoroethylene liner, and the aged solution was poured into the liner. The liner was placed in a crystallization kettle and sealed, and then crystallized in a constant temperature oven at 430 K for 70 min. Finally, the obtained sample was washed and dried, and then placed in a tube furnace and calcined at 823 K for 2 h to obtain the b-axis oriented ZSM-5 seed material b5-ZSM-5 / CG. seed The heating and cooling rates were 0.5 K / min.

[0094] The TPAOH, TEOS, water and sodium metaaluminate with a molar ratio of 0.25:1:165:0.005 were uniformly mixed and aged at 70°C for 2 h. The above b5-ZSM-5 / CG was placed in a hydrothermal kettle, and then the synthesis solution was poured into the kettle. The hydrothermal reaction was carried out in an oven at 400 K for 23 h. After the reaction, the sample was washed by centrifugation and dried in an oven at 80°C for 24 h to obtain the b5-ZSM-5 / CG molecular sieve membrane sample. seed

[0095] Table 8 Catalytic performance of molecular sieves

[0096]

[0097] Table 8 shows the methanol conversion rate and aromatic selectivity data 2 h after the reaction. It can be seen that, compared with the conventional ZSM-5, the b-axis oriented ZSM-5 has higher methanol conversion rate and aromatic selectivity, which indicates that the prepared b5-ZSM-5 / CG has more excellent performance.

[0098] Example 6

[0099] The coal gangue from Zhouyuanshan coal mine was crushed by a crusher, and the powder was obtained by passing through a 200 mesh sieve. The sample was acid treated with a mixed acid prepared by mixing 15% HCl and 25% H2SO4 at a volume ratio of 1:0.5, and the amount of mixed acid used was 5 g for 1 g of powder.

[0100] ​The mixed solution was continuously stirred at 40°C for 5 h, and finally left to stand at room temperature for 12 h, and centrifuged and dried. Subsequently, the acid-treated coal gangue powder was placed in a 0.05 mol / L potassium permanganate solution at a temperature of 373 K and stirred for 15 min, and the mass ratio of the coal gangue powder to the potassium permanganate solution was 1:5. Then, the sample was filtered, washed, and dried to obtain the acid-treated coal gangue H-CG6.

[0101] The H-CG6 was placed in a muffle furnace and calcined at 873 K for 2 h to obtain a quartz crystal phase. After the reaction was completed, the sample was left to cool at room temperature, and then the coal gangue powder was again subjected to acid treatment with a mixed acid prepared by mixing 15% HCl and 25% H2SO4 at a volume ratio of 1:0.5, and the amount of the mixed acid used was 5 g for 1 g of the powder.

[0102] The acid-treated coal gangue powder 10 g was pressed into a tablet by a tablet press, and then calcined at 100°C for 30 min in a muffle furnace, and the pressing intensity of the tablet press was constant at 1 MPa and the pressing time was 1 min. Then, the coal gangue tablet was sequentially subjected to ultrasonic cleaning in acetone, anhydrous ethanol, and deionized water for 10 min, and then dried and placed in an oven at 373 K for 12 h. The obtained solid sample was used as a base material CG6.

[0103] The TPAOH, water, and TEOS in a molar ratio of 0.25:165:1 were uniformly mixed and aged at 25°C for 24 h. The base material CG6 was vertically placed at the bottom of a polytetrafluoroethylene liner, and the aged solution was poured into the liner, which was then sealed in a crystallization kettle, and then crystallized in an oven at 430 K for 70 min. Finally, the obtained sample was washed and dried, and then placed in a tube furnace and calcined at 823 K for 2 h to obtain a b-axis oriented ZSM-5 seed material b6-ZSM-5. seed / CG, and the heating and cooling rates were 0.5 K / min.

[0104] The TPAOH, TEOS, water, and sodium metaaluminate in a molar ratio of 0.30:1:165:0.005 were uniformly mixed and aged at 70°C for 2 h. The above b6-ZSM-5 / CG was placed in a hydrothermal kettle, and then the synthesis solution was poured into the kettle, and then hydrothermally treated in an oven at 400 K for 23 h. After the treatment was completed, the sample was centrifuged, washed, and dried in an oven at 80°C for 24 h to obtain a b6-ZSM-5 / CG molecular sieve membrane sample. seed / CG, and the heating and cooling rates were 0.5 K / min.

[0105] Table 9 Catalytic properties of the molecular sieves

[0106]

[0107] Table 9 is the methanol conversion and aromatic selectivity data after 2h of reaction, it can be seen that the b-axis oriented ZSM-5 has higher conversion and aromatic selectivity than the conventional ZSM-5, which indicates that the prepared b6-ZSM-5 / CG has more excellent performance.

[0108] Example 7

[0109] The coal gangue from Zhouyuanshan coal mine was crushed by a crusher and sieved to obtain a powder through a 200-mesh sieve. The sample was acid-treated with a mixed acid prepared from 15% HC1 and 25% H2SO4 at a volume ratio of 1:0.5, and the amount used was 5g of mixed acid for 1g of powder.

[0110] The mixed solution was continuously stirred at 40°C for 5h, and finally left to stand at room temperature for 12h, and centrifuged and dried. Subsequently, the acid-treated coal gangue powder was placed in a 0.05mol / L potassium permanganate solution at 373K and stirred for 15min, and the mass ratio of the coal gangue powder to the potassium permanganate solution was 1:5. Then, it was filtered, washed, and dried to obtain the acid-treated coal gangue H-CG7.

[0111] The H-CG7 was calcined in a muffle furnace at 873K for 2h to obtain a quartz crystal phase. After the reaction was completed, it was left to cool at room temperature, and then the coal gangue powder was again acid-treated with a mixed acid prepared from 15% HC1 and 25% H2SO4 at a volume ratio of 1:0.5, and the amount used was 5g of mixed acid for 1g of powder.

[0112] 10g of the acid-treated coal gangue powder was pressed into a tablet by a tablet press and then calcined in a muffle furnace at 100°C for 30min, and the pressing intensity of the tablet press was constant at 1.2MPa and the time was 1min. Then, the coal gangue tablet was sequentially ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water for 10min, and then dried and placed in an oven at 373K for 12h. The obtained solid sample was used as the base material CG7.

[0113] The TPAOH, water, and TEOS at a molar ratio of 0.25:165:1 were uniformly mixed and aged at 25°C for 24h. The base material CG7 was vertically placed at the bottom of a polytetrafluoroethylene liner, and the aged solution was poured into the liner, which was then placed in a crystallization kettle and sealed, and then crystallized in a constant-temperature box at 430K for 70min. Finally, the obtained sample was washed, dried, and placed in a tube furnace and calcined at 823K for 2h to obtain the b-axis oriented ZSM-5 seed material b7-ZSM-5 / CG. seed / CG, and the heating and cooling rates were 0.5K / min.

[0114] The TPAOH, TEOS, water, and sodium metaaluminate at a molar ratio of 0.25:1:165:0.005 were uniformly mixed and aged at 70°C for 2h. The above b7-ZSM-5 / CG was placed in a 0.05mol / L potassium permanganate solution at 373K and stirred for 15min, and the mass ratio of the b7-ZSM-5 / CG to the potassium permanganate solution was 1:5. Then, it was filtered, washed, and dried to obtain the b-axis oriented ZSM-5 seed material b7-ZSM-5 / CG.seed The / CG was placed in a hydrothermal kettle, then the synthesis solution was poured in, and hydrothermal reaction was carried out in a 400 K oven for 23 h. After the end of the reaction, centrifugal washing was carried out and drying was carried out in an oven at 80 °C for 24 h to obtain a b7-ZSM-5 / CG molecular sieve membrane sample.

[0115] Table 10 catalytic performance of the molecular sieve

[0116]

[0117] Table 10 is the methanol conversion rate and aromatic selectivity data 2 h after the reaction, it can be seen that the b-axis oriented ZSM-5 has higher methanol conversion rate and aromatic selectivity than the conventional ZSM-5, which indicates that the prepared b7-ZSM-5 / CG has more excellent performance.

[0118] Example 8

[0119] The coal gangue from Zhouyuanshan coal mine was crushed by a crusher and passed through a 180-mesh sieve to obtain a powder. The sample was acid-treated with a mixed acid prepared from 15% HC1 and 25% H2SO4 in a volume ratio of 1:1, and the amount used was 8 g of mixed acid for 1 g of powder.

[0120] The mixed solution was continuously stirred at 45 °C for 5.5 h, and finally left to stand at room temperature for 12 h, and centrifuged and dried. Then the acid-treated coal gangue powder was placed in a 0.08 mol / L potassium permanganate solution at a temperature of 373 K and stirred for 18 min, and the mass ratio of the coal gangue powder to the potassium permanganate solution was 1:8. Then it was filtered, washed and dried to obtain the acid-treated coal gangue H-CG8.

[0121] The H-CG8 was placed in a muffle furnace and calcined at 1123 K for 2.5 h to obtain a quartz crystal phase. After the reaction was completed, it was cooled at room temperature, and then the coal gangue powder was again acid-treated with a mixed acid prepared from 15% HC1 and 25% H2SO4 in a volume ratio of 1:1, and the amount used was 8 g of mixed acid for 1 g of powder.

[0122] A mass fraction of 0.5% pore-forming agent ammonium bicarbonate powder was added to the acid-treated coal gangue powder, and after uniform mixing, 10 g of the acid-treated coal gangue powder was weighed and pressed into a tablet by a tablet press, and then calcined at 100 °C in a muffle furnace for 30 min, and the pressing intensity of the tablet press was constant at 1.0 MPa and the time was 70 s. Then the coal gangue tablet was sequentially ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 10 min, and dried and placed in an oven at 373 K for 12 h. The obtained solid sample was used as the base material CG8.

[0123] TPAOH, water and TEOS in a molar ratio of 0.3:165:1 were mixed uniformly and aged at 30°C for 24h. The substrate material CG8 was vertically placed at the bottom of a polytetrafluoroethylene lined autoclave, the aged solution was poured into the lined autoclave, which was then sealed and crystallized in an oven at 450K for 80min. Finally, the obtained sample was washed, dried and calcined in a tube furnace at 823K for 2h to obtain the b-axis oriented ZSM-5 seed material b8-ZSM-5 seed The temperature was raised and lowered at a rate of 0.5K / min.

[0124] TPAOH, TEOS, water and sodium aluminate in a molar ratio of 0.30:1:165:0.005 were mixed uniformly and aged at 80°C for 2.5h. The above b8-ZSM-5 seed / CG was placed in an autoclave, and then the synthesis solution was poured into the autoclave, which was then hydrothermally treated in an oven at 420K for 24h. After the end of the treatment, the sample was centrifuged, washed and dried in an oven at 80°C for 24h to obtain the b8-ZSM-5 / CG molecular sieve membrane sample.

[0125] Table 11 Catalytic performance of the molecular sieve

[0126]

[0127] Table 11 shows the conversion of methanol and the selectivity of aromatic hydrocarbons 2h after the reaction. It can be seen that the b-axis oriented ZSM-5 has higher conversion of methanol and selectivity of aromatic hydrocarbons than the conventional ZSM-5, which indicates that the prepared b8-ZSM-5 / CG has better performance.

[0128] From the above Examples 1-8, it can be seen that the optimal preparation conditions are described in Example 8. Under the preparation conditions, the b8-ZSM-5 seed / CG has the highest degree of b-axis orientation, the surface of the b8-ZSM-5 / CG molecular sieve membrane is continuous and the smoothest, and the catalytic activity is the best.

[0129] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a b-axis-ZSM-5 membrane / coal gangue catalyst, characterized in that: The following steps are involved: Preparation of flaky gangue carrier material: Gangue powder is sequentially subjected to primary acid deashing treatment and oxidant desulfurization treatment, and then sequentially subjected to filtration, washing, drying, calcination and secondary acid deashing and drying to obtain gangue pretreated powder; The pretreated coal gangue powder and the pore-forming agent are mixed, pressed into tablets and calcined to obtain the flaky coal gangue carrier material CG. Synthesis of b-axis-ZSM-5 seed crystals / coal gangue: Tetrapropylammonium hydroxide, water and ethyl orthosilicate were mixed and aged; the flaky coal gangue carrier material CG was placed vertically at the bottom of the aged solution, and then crystallized, washed, dried and calcined in sequence to obtain b-axis-ZSM-5 seed crystals / coal gangue b-ZSM-5. seed / CG; Hydrothermal preparation of b-axis-ZSM-5 membrane / coal gangue catalyst: Tetrapropylammonium hydroxide, ethyl orthosilicate, water and sodium metaaluminate were mixed and aged to obtain a mixed solution; b-axis-ZSM-5 seed crystals / coal gangue b-ZSM-5 seed / CG is placed at the bottom of the mixed solution, washed and dried after hydrothermal treatment to obtain the b-axis-ZSM-5 membrane / coal gangue catalyst b-ZSM-5 / CG.

2. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: In the preparation of the flaky gangue carrier material, the gangue powder comprises: 45%-55% silicon oxide, 20%-30% aluminum oxide, and 1.5%-2.5% titanium dioxide; The particle size of the coal gangue powder is 150 meshes to 200 meshes.

3. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: In the preparation of the flaky gangue carrier material, the mixed acid used for the primary acid deashing and the secondary acid deashing is 15% HCl and 25% H2SO4 in a volume ratio of 1: (0.5-1.5); The mass ratio of the coal gangue powder to the mixed acid is 1:(5-10), the treatment temperature of the primary acid deashing and the secondary acid deashing are both 40-50° C., and the treatment time is both 5-6 hours.

4. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: The oxidant in the oxidant desulfurization treatment is potassium permanganate solution with a concentration of 0.05mol / L-0.1mol / L, the mass ratio of the coal gangue powder to the oxidant is 1:(5-10), the oxidation time is 15min-20min, and the oxidation temperature is 363K-383K.

5. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: The calcination temperature between the primary acid deashing treatment and the secondary acid deashing treatment is 873K-1123K, and the calcination time is 2h-3h.

6. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: The mixing mass ratio of the coal gangue pretreatment powder and the pore-forming agent is 1:(0-0.1), and the pore-forming agent is ammonium bicarbonate; The forming pressure in the tableting process of the flaky gangue carrier material preparation is 0.8 MPa-1.2 MPa, and the holding time is 60s-80s.

7. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: In the b-axis-ZSM-5 seed / coal gangue synthesis, the molar ratio of tetrapropylammonium hydroxide, water and ethyl orthosilicate is (0.25-0.35):165:1; the aging temperature is 25°C-35°C, and the aging time is 20h-24h.

8. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: In the b-axis-ZSM-5 seed / gangue synthesis, the flaky gangue carrier material CG has a crystallization temperature of 430K-470K in a mixed solution, a crystallization time of 70min-90min, a calcination temperature of 823K after drying, and a calcination time of 2h.

9. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: In the hydrothermal preparation of the b-axis-ZSM-5 membrane / coal gangue catalyst, the mixing molar ratio of tetrapropylammonium hydroxide, ethyl orthosilicate, water, and sodium aluminate is (0.25-0.35):1:165:0.005, the aging temperature is 70°C-90°C, and the aging time is 2h-3h.

10. The method for preparing the b-axis-ZSM-5 membrane / coal gangue catalyst according to claim 1, characterized in that: In the hydrothermal preparation of the b-axis-ZSM-5 membrane / coal gangue catalyst, the b-axis-ZSM-5 seed crystal / coal gangue b-ZSM-5 seed The hydrothermal temperature of / CG at the bottom of the mixed solution is 400K-440K, and the time is 23h-25h.

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