Method for rapidly removing molecular sieve template agent

Abstract

The invention discloses a method for rapidly removing a molecular sieve template agent, which comprises the following steps: a flame spray gun is used for carrying out flame calcination treatment on a molecular sieve containing the template agent, and the temperature of the outer flame of the flame spray gun is 700-800 DEG C. Compared with a method for removing the template agent by calcining the molecular sieve through a muffle furnace, the method for removing the template agent by calcining the molecular sieve through a flame method has the advantages that the removal period can be directly shortened to be within five minutes, and a thermogravimetric test of the calcined molecular sieve shows that the method can effectively remove the template agent of the molecular sieve and is a novel method for rapidly removing the template agent of the molecular sieve; and energy consumption and waste gas pollution can be reduced. The catalytic performance of the molecular sieve obtained by using a flame method to quickly calcine and remove the template agent in a methanol-to-olefin reaction is close to that of a traditional molecular sieve obtained by using a muffle furnace to calcine and remove the template agent.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieves, and in particular to a method for rapidly removing a molecular sieve template agent. Background Art

[0002] Molecular sieve is a porous material with an ordered pore structure, a large specific surface area, adjustable acidity, excellent thermal stability and good selectivity. It is widely used in the fields of gas adsorption and separation, catalysis, etc. Except for a few molecular sieves that can be synthesized by cation guidance, most molecular sieve syntheses require the use of templates, such as organic amines, quaternary ammonium salts or organic metal complexes. The template added during the synthesis process mainly exists in the micropores in the molecular sieve structure. In order to make the molecular sieve have an ordered pore structure, it is necessary to calcine it at high temperature to remove the template before using it. The temperature used by this method is generally 550°C or above, and the calcination time is relatively long, generally 4 to 12 hours. For example, Xiao et al. calcined the nanosheet S-1 (MFI) with tetrapropylammonium hydroxide at 550°C for 4 hours in an air atmosphere to remove the template (Nat. Nanotechnol. 2022.7.17); Li et al. calcined the nanosheet S-1 (MFI) with tetrapropylammonium hydroxide at 550°C for 4 hours in an air atmosphere to remove the template (Inorg. Chem. Front. 2021.8.2315). The prior art method of removing the template by high-temperature calcination uses high-temperature and long-term calcination, which has a slow removal rate and takes a long time, resulting in a long synthesis cycle and high energy consumption. The oxidation reaction of the template during the calcination process produces waste gas, so long-term calcination is not environmentally friendly. A muffle furnace is generally used for high-temperature calcination. The cost of the muffle furnace is high, and the internal space of the muffle furnace is limited, so the amount of air is limited. A large number of samples cannot be calcined at one time, otherwise the template will not be completely removed. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a method for quickly removing the molecular sieve template.

[0004] The above object of the present invention is achieved through the following technical solutions:

[0005] A method for rapidly removing a molecular sieve template comprises the following steps: using a flame spray gun to flame calcine a molecular sieve containing the template, wherein the temperature of the outer flame of the flame spray gun is 700-800°C.

[0006] The present invention adopts a flame method to calcine the molecular sieve to remove the template agent. The outer flame of the flame spray gun is in direct contact with the molecular sieve. The temperature of the outer flame of the spray gun is sufficient to remove the template agent of the molecular sieve, and the template agent in the molecular sieve pores can be completely removed in a very short time. The method solves the disadvantage of the long calcination time of the muffle furnace, thereby shortening the exhaust gas emission time and reducing energy consumption. Moreover, more molecular sieves can be calcined at one time without using the muffle furnace, and there is sufficient air to calcine the molecular sieve until the template agent is completely removed. From the cost aspect, the cost of using the flame spray gun in the present invention is lower than that of the muffle furnace.

[0007] Furthermore, the template agent is selected from one or more of organic ammonium, quaternary ammonium salt and metal organic complex.

[0008] Furthermore, the molecular sieve is a non-metallic molecular sieve.

[0009] Furthermore, the molecular sieve is one or more selected from pure silicon molecular sieve, silicon aluminum molecular sieve, silicon aluminum phosphate molecular sieve and aluminum phosphate molecular sieve.

[0010] Furthermore, the content of the template in the molecular sieve is 5 to 30 wt%.

[0011] Furthermore, the dosage of the molecular sieve is 0.1 to 1 g.

[0012] Furthermore, the molecular sieve is dried.

[0013] Furthermore, the drying treatment method is selected from one or more of heating drying, freeze drying and supercritical drying.

[0014] Furthermore, the flame calcination treatment time is 1 to 5 minutes, preferably 2 to 4 minutes.

[0015] Beneficial effects of the present invention:

[0016] The present invention adopts a flame method to calcine the molecular sieve to remove the template agent. Compared with the method of removing the template agent by calcining in a muffle furnace, the removal cycle can be directly shortened to within five minutes. Thermogravimetric test of the molecular sieve after calcination shows that the method can effectively remove the template agent of the molecular sieve. The method is a new method for quickly removing the template agent of the molecular sieve, which can reduce energy consumption and waste gas pollution.

[0017] The method for rapidly removing the template agent of the molecular sieve provided by the present invention eliminates the limitation of the muffle furnace on the sample quality and can remove the template agent of a large amount of molecular sieves at one time.

[0018] The catalytic performance of the molecular sieve obtained by the invention with the template agent removed is equivalent to the catalytic performance of the molecular sieve with the template agent removed by using a muffle furnace, and has a high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The XRD diagrams and thermogravimetric diagrams of the SAPO-34-nanosheet molecular sieve and SAPO-34-block molecular sieve with the template removed are shown; wherein (a) is the XRD diagram of the SAPO-34-nanosheet molecular sieve with the template removed obtained in Example 1 and Comparative Example 1, the SAPO-34-block molecular sieve with the template removed obtained in Example 2 and Comparative Example 2, and the SAPO-34-nanosheet molecular sieve and SAPO-34-block molecular sieve with the template not removed; (b) is the thermogravimetric diagram of the SAPO-34-nanosheet molecular sieve with the template removed obtained in Example 1 and the SAPO-34-block molecular sieve with the template removed obtained in Example 2.

[0020] Figure 2 The XRD diagram and thermogravimetric diagram of the AlPO-34 molecular sieve with the template removed; wherein, (a) is the XRD diagram of the AlPO-34 molecular sieve with the template removed obtained in Example 3 and Comparative Example 3 and the AlPO-34 molecular sieve with the template not removed, and (b) is the thermogravimetric diagram of the AlPO-34 molecular sieve with the template removed obtained in Example 3.

[0021] Figure 3 The figures are XRD diagrams and thermogravimetric diagrams of the SAPO-18 molecular sieve with the template removed; wherein, (a) is the XRD diagram of the SAPO-18 molecular sieve with the template removed obtained in Example 4 and Comparative Example 4 and the SAPO-18 molecular sieve with the template not removed, and (b) is the thermogravimetric diagram of the SAPO-18 molecular sieve with the template removed obtained in Example 4.

[0022] Figure 4 The figures are XRD diagrams and thermogravimetric diagrams of the SAPO-35 molecular sieve with the template removed; wherein, (a) is the XRD diagram of the SAPO-35 molecular sieve with the template removed obtained in Example 5 and Comparative Example 5 and the SAPO-35 molecular sieve with the template not removed, and (b) is the thermogravimetric diagram of the SAPO-35 molecular sieve with the template removed obtained in Example 5.

[0023] Figure 5 The figures are XRD diagrams and thermogravimetric diagrams of the ZSM-5 molecular sieve with the template removed; wherein, (a) is the XRD diagram of the ZSM-5 molecular sieve with the template removed obtained in Example 6 and Comparative Example 6 and the ZSM-5 molecular sieve with the template not removed, and (b) is the thermogravimetric diagram of the ZSM-5 molecular sieve with the template removed obtained in Example 6.

[0024] Figure 6The figures are the XRD diagram and thermogravimetric diagram of the S-1 molecular sieve with the template removed; wherein, (a) is the XRD diagram of the S-1 molecular sieve with the template removed obtained in Example 7 and Comparative Example 7 and the S-1 molecular sieve with the template not removed, and (b) is the thermogravimetric diagram of the S-1 molecular sieve with the template removed obtained in Example 7.

[0025] Figure 7 The catalytic performance comparison chart of SAPO-34-block molecular sieve without calcination treatment, SAPO-34-block molecular sieve with template removed obtained in Example 2 and SAPO-34-block molecular sieve with template removed obtained in Comparative Example 2 for methanol to olefins (MTO) reaction is shown in FIG. 1 ; wherein (a) is a comparison chart of MTO lifetime, and (b) is a comparison chart of diene selectivity. DETAILED DESCRIPTION

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] The invention provides a method for rapidly removing a molecular sieve template, comprising the following steps: using a flame spray gun to flame calcine a molecular sieve containing the template, wherein the temperature of the outer flame of the flame spray gun is 700-800°C.

[0028] In a specific embodiment, the molecular sieve containing the template is placed in a porcelain boat, the porcelain boat is placed on an iron net, and the molecular sieve is directly flame-calcined using the outer flame of a spray gun.

[0029] The molecular sieve used in the present invention is a non-metallic molecular sieve, and the provided method of direct flame calcination to remove the template is applicable to most molecular sieve configurations, such as pure silicon molecular sieve S-1, silicon aluminum molecular sieve ZSM-5, silicon aluminum phosphate molecular sieve SAPO-18, silicon aluminum phosphate molecular sieve SAPO-34, silicon aluminum phosphate molecular sieve SAPO-35, aluminum phosphate molecular sieve AlPO-34, etc.

[0030] The template used in the present invention is a compound that serves as a structural guide during the synthesis of the molecular sieve, and may be an organic ammonium, a quaternary ammonium salt, a metal organic complex, or the like.

[0031] The molecular sieve used in the present invention is dried, and the drying can be carried out by conventional operation methods in the art, such as heating drying, freeze drying, supercritical drying, etc.

[0032] In a specific embodiment, the molecular sieve can be placed in an oven at 80-100° C. and dried in an air atmosphere for 8-12 hours.

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0034] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0035] In the following examples, the organic matter content of the sample is determined based on the results of thermogravimetric analysis. The test method is as follows: a TGAQ600 instrument is used for testing, wherein the sample loading amount is 10 mg, and the temperature is increased from 30°C to 800°C in an air atmosphere at a heating rate of 10°C / min. Whether the sample has a weight loss peak after 300°C is used to determine whether the molecular sieve template is completely removed.

[0036] In the following examples and comparative examples, SAPO-34-nanosheet molecular sieves were prepared by the following method: the synthesis ratio (molar ratio) of Al2O3:P2O5:SiO2:TEAOH:H2O was 1:1.2:0.6:2:40. 10.2 g aluminum isopropoxide (C9H 21 AlO3) was added to 21g tetraethylammonium hydroxide (TEAOH, 35wt%) in three portions and stirred for 1 hour. 6.9g phosphoric acid (H3PO4, 85wt%) was slowly dripped thereinto. After stirring for 2 hours, 2.25g silica sol (SiO2, 40wt%) was dripped in and continued to be stirred for 2 hours. The mixture was placed in a stainless steel hydrothermal reactor and crystallized in an oven at 170°C for 3 days. The obtained solid was centrifuged and washed 3 times with deionized water, and dried overnight in an oven at 80°C for use.

[0037] In the following examples and comparative examples, SAPO-34-block molecular sieves were prepared by the following method: the synthetic ratio (molar ratio) of Al2O3:P2O5:SiO2:TEA:H2O was 1:1:0.4:4.7:70. 3.49 g of pseudo-boehmite was added to 27.2 g of water and stirred for 1 hour, then 5.12 g of phosphoric acid (85 wt%) was added dropwise and stirred for 2 hours, 10.47 g of triethylamine (TEA) was added dropwise and stirred for 2 hours, and finally 0.52 g of white carbon black was added and stirred for 2 hours, and then placed in a stainless steel hydrothermal reactor and placed in a 200°C oven for crystallization for 36 hours. The obtained solid was centrifuged and washed 3 times with deionized water, and placed in an oven at 80°C for overnight drying for use.

[0038] In the following examples and comparative examples, the AlPO-34 molecular sieve was prepared by the following method: the synthetic ratio (molar ratio) of Al2O3:P2O5:HF:MOR:H2O was 1:1:1:2.5:100. 3.49 g of pseudo-boehmite was added to 37.3 g of distilled water, followed by dropwise addition of 5.12 g of phosphoric acid, stirring for 1 h, then dropwise addition of 4.84 g of morpholine, continued stirring for 1 h, and finally addition of 1.11 g of hydrofluoric acid (40 wt%), stirring for 2 h, and then placed in a stainless steel reactor and placed in a 200°C oven for crystallization for 3 days. The obtained solid was centrifuged and washed 3 times with deionized water, and placed in an 80°C oven to dry overnight for use.

[0039] The SAPO-18 molecular sieve in the following examples and comparative examples was prepared by the following method: the synthetic ratio (molar ratio) of Al2O3:P2O5:SiO2:DIPEA:H2O was 1:1.2:0.3:2:50. 11.5g phosphoric acid (98wt%) was added to 43.7g distilled water, and 7.8g aluminum hydroxide was added after stirring for 10min, and stirred for 2h, and then 12.9g N,N-diisopropylethylamine (DIPEA, 99wt%) was added thereto, stirred for 1h, and finally 2.25g silica sol (40wt%) was added, and after stirring for 2h, it was loaded into a stainless steel reactor and placed in an oven at 180°C for crystallization for 2 days. The obtained solid was centrifuged and washed 3 times with deionized water, and placed in an oven at 80°C for overnight drying for use.

[0040] The SAPO-35 molecular sieve in the following examples and comparative examples was prepared by the following method: the synthetic ratio (molar ratio) of Al2O3:P2O5:SiO2:NMP:H2O was 1:1.2:0.6:6.15:123.8. 1.05g of boehmite was dispersed in 8mL of water, 1.66g of phosphoric acid (98wt%) was added and stirred for 1h, 0.45g of tetraethyl orthosilicate was slowly added and stirred for 3h, then 2.70mL of N-methylpiperidine was added dropwise, stirred for 2h, loaded into a stainless steel reactor and placed in an oven at 180°C for crystallization for 3 days. The obtained solid was centrifuged and washed 3 times with deionized water, and placed in an oven at 80°C for overnight drying for use.

[0041] The ZSM-5 molecular sieve in the following examples and comparative examples is prepared by the following method: the synthetic ratio (molar ratio) of TEOS:TPAOH:NaAlO2:NaOH:H2O is 1:1.4:0.1:0.02:7. 25.21g of tetrapropylammonium hydroxide (TPAOH) and 10.82g of distilled water are mixed and stirred for 10min, then 17.95g of tetraethyl orthosilicate is added, stirred for 2h, then 0.071g of sodium aluminate is added, stirring is continued for 1h, and finally 0.063g of sodium hydroxide (>98wt%) is added dropwise, stirred for 2h, and then loaded into a stainless steel reactor and placed in a 200°C oven for crystallization for 3 days. The prepared ZSM-5 is ion exchanged 3 times using ammonium chloride (99wt%) solution. The obtained solid is centrifuged and washed 3 times with deionized water, and placed in an oven at 80°C for overnight drying for use.

[0042] The S-1 molecular sieve in the following examples and comparative examples is prepared by the following method: the synthesis ratio (molar ratio) of TEOS:TPAOH:H2O is 1:0.24:20. 8.32g of tetraethyl orthosilicate (TEOS) and 7.81g of tetrapropylammonium hydroxide (TPAOH) are added to 7.50g of deionized water. The mixed liquid is stirred at room temperature for 18h and then transferred to a 100mL stainless steel hydrothermal reactor. The reactor is placed in an oven at 90°C and crystallized for 2 days under static conditions. The resulting solid is centrifuged and washed 3 times with deionized water, and placed in an oven at 80°C to dry overnight for use.

[0043] Example 1

[0044] A method for removing a SAPO-34-nanosheet molecular sieve template comprises the following steps:

[0045] Take 1g of SAPO-34-nanosheet molecular sieve, divide it into 5 portions and put it into a porcelain boat. Place the porcelain boat on an iron net and use the outer flame of a flame spray gun (temperature is about 750°C) to directly flame calcine the molecular sieve for 2 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black and finally to white, thereby obtaining the SAPO-34-nanosheet molecular sieve with the template removed.

[0046] Example 2

[0047] A method for removing SAPO-34-block molecular sieve templates comprises the following steps:

[0048] Take 1g of SAPO-34-block molecular sieve, divide it into 5 portions and put it into a porcelain boat, place the porcelain boat on an iron net, and use the outer flame of a flame spray gun (temperature is about 750°C) to directly flame calcinate the molecular sieve for 2 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black, and finally to white, to obtain the SAPO-34-block molecular sieve with the template removed.

[0049] Example 3

[0050] A method for removing an AlPO-34 molecular sieve template comprises the following steps:

[0051] Take 1g of AlPO-34 molecular sieve, divide it into 5 parts and put it into a porcelain boat. Place the porcelain boat on an iron net and use the outer flame of a flame spray gun (temperature is about 750°C) to directly flame calcine the molecular sieve for 5 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black and finally to white, thereby obtaining the AlPO-34 molecular sieve with the template removed.

[0052] Example 4

[0053] A method for removing a SAPO-18 molecular sieve template comprises the following steps:

[0054] Take 1g of SAPO-18 molecular sieve, divide it into 5 parts and put it into a porcelain boat, place the porcelain boat on an iron net, and use the outer flame of a flame spray gun (temperature is about 750°C) to directly flame calcinate the molecular sieve for 4 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black, and finally to white, to obtain the SAPO-18 molecular sieve with the template removed.

[0055] Example 5

[0056] A method for removing a SAPO-35 molecular sieve template comprises the following steps:

[0057] Take 1g of SAPO-35 molecular sieve, divide it into 5 parts and put it into a porcelain boat. Put the porcelain boat on an iron net and use the outer flame of a flame spray gun (temperature is about 750℃) to directly flame calcine the molecular sieve for 3 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black and finally to white, thereby obtaining the SAPO-35 molecular sieve with the template removed.

[0058] Example 6

[0059] A method for removing a ZSM-5 molecular sieve template comprises the following steps:

[0060] Take 1g of ZSM-5 molecular sieve, divide it into 5 parts and put it into a porcelain boat, place the porcelain boat on an iron net, and use the outer flame of a flame spray gun (temperature is about 750℃) to directly flame calcine the molecular sieve for 4 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black and finally to white, thereby obtaining the ZSM-5 molecular sieve with the template removed.

[0061] Example 7

[0062] A method for removing an S-1 template comprises the following steps:

[0063] Take 1g of S-1 molecular sieve, divide it into 5 portions and put it into a porcelain boat. Place the porcelain boat on an iron net and use the outer flame of a flame spray gun (temperature is about 750°C) to directly flame calcine the molecular sieve for 5 minutes. During the flame calcination treatment, it is necessary to move back and forth to prevent the porcelain boat from local overheating and cracking. During the flame calcination process, the molecular sieve changes from white to yellow to black and finally to white, thereby obtaining the S-1 molecular sieve with the template removed.

[0064] Comparative Example 1

[0065] A method for removing a SAPO-34-nanosheet molecular sieve template agent comprises the following steps: taking 1 g of the SAPO-34-nanosheet molecular sieve, placing it in a muffle furnace, and calcining it at 550° C. for 6 hours in an air atmosphere to obtain a SAPO-34-nanosheet molecular sieve with the template agent removed.

[0066] Comparative Example 2

[0067] A method for removing a SAPO-34 block molecular sieve template agent comprises the following steps: taking 1 g of the SAPO-34 block molecular sieve, placing it in a muffle furnace, and calcining it at 550° C. for 6 hours in an air atmosphere to obtain the SAPO-34 block molecular sieve with the template agent removed.

[0068] Comparative Example 3

[0069] A method for removing a template agent from an AlPO-34 molecular sieve comprises the following steps: taking 1 g of the AlPO-34 molecular sieve, placing it in a muffle furnace, and calcining it at 550° C. for 6 hours in an air atmosphere to obtain the AlPO-34 molecular sieve from which the template agent has been removed.

[0070] Comparative Example 4

[0071] A method for removing a SAPO-18 molecular sieve template agent comprises the following steps: taking 1 g of the SAPO-18 molecular sieve, placing it in a muffle furnace, and calcining it at 550° C. for 6 hours in an air atmosphere to obtain the SAPO-18 molecular sieve with the template agent removed.

[0072] Comparative Example 5

[0073] A method for removing a template agent from a SAPO-35 molecular sieve comprises the following steps: 1 g of the SAPO-35 molecular sieve is placed in a muffle furnace and calcined at 550° C. for 6 hours in an air atmosphere to obtain a SAPO-35 molecular sieve with the template agent removed.

[0074] Comparative Example 6

[0075] A method for removing a template agent from a ZSM-5 molecular sieve comprises the following steps: taking 1 g of the ZSM-5 molecular sieve, placing it in a muffle furnace, and calcining it at 550° C. for 6 hours in an air atmosphere to obtain a ZSM-5 molecular sieve with the template agent removed.

[0076] Comparative Example 7

[0077] A method for removing a template agent of an S-1 molecular sieve comprises the following steps: taking 1 g of the S-1 molecular sieve, placing it in a muffle furnace, and calcining it at 550° C. for 6 hours in an air atmosphere to obtain the S-1 molecular sieve with the template agent removed.

[0078] X-ray diffractometer (XRD) was used to characterize the crystal structure of the molecular sieve, and the results of thermogravimetric analysis were used to determine whether the molecular sieve template was completely removed. Figure 1 The XRD diagram and thermogravimetric diagram of SAPO-34-nanosheet molecular sieve and SAPO-34-block molecular sieve with the template removed; wherein, (a) is the XRD diagram of the SAPO-34-nanosheet molecular sieve with the template removed obtained in Example 1 and Comparative Example 1, the SAPO-34-block molecular sieve with the template removed obtained in Example 2 and Comparative Example 2, and the SAPO-34-nanosheet molecular sieve and SAPO-34-block molecular sieve without the template removed; (b) is the thermogravimetric diagram of the SAPO-34-nanosheet molecular sieve with the template removed obtained in Example 1 and the SAPO-34-block molecular sieve with the template removed obtained in Example 2 (the solid line represents the change in the mass of the molecular sieve sample with the increase in temperature; the dotted line represents the change in the weight loss rate of the molecular sieve sample with the increase in temperature). Figure 1 As can be seen in (b), the SAPO-34-nanosheet molecular sieve and SAPO-34-block molecular sieve without the template have no obvious weight loss peak after 300°C, proving that the flame calcination treatment can completely remove the template.

[0079] Figure 2 The XRD graph and thermogravimetric graph of the AlPO-34 molecular sieve with the template removed; (a) is the XRD graph of the AlPO-34 molecular sieve with the template removed obtained in Example 3 and Comparative Example 3 and the AlPO-34 molecular sieve without the template removed, (b) is the thermogravimetric graph of the AlPO-34 molecular sieve with the template removed obtained in Example 3. Figure 2As can be seen in (b), the AlPO-34 molecular sieve without the template has no obvious weight loss peak after 300°C, proving that the flame calcination treatment can completely remove the template.

[0080] Figure 3 The XRD patterns and thermogravimetric patterns of the SAPO-18 molecular sieves with the template removed are shown in Figures 4 and 4; (a) is the XRD pattern of the SAPO-18 molecular sieves with the template removed and the SAPO-18 molecular sieves without the template removed obtained in Example 4 and Comparative Example 4; (b) is the thermogravimetric pattern of the SAPO-18 molecular sieves with the template removed obtained in Example 4. Figure 3 As can be seen in (b), the SAPO-18 molecular sieve without the template has no obvious weight loss peak after 300°C, proving that the flame calcination treatment can completely remove the template.

[0081] Figure 4 The XRD diagram and thermogravimetric diagram of the SAPO-35 molecular sieve with the template removed are shown in Figures 5 and 6; (a) is the XRD diagram of the SAPO-35 molecular sieve with the template removed obtained in Example 5 and Comparative Example 5 and the SAPO-35 molecular sieve without the template removed, and (b) is the thermogravimetric diagram of the SAPO-35 molecular sieve with the template removed obtained in Example 5. Figure 4 As can be seen in (b), the SAPO-35 molecular sieve without the template has no obvious weight loss peak after 300°C, proving that the flame calcination treatment can completely remove the template.

[0082] Figure 5 The XRD graph and thermogravimetric graph of the ZSM-5 molecular sieve with the template removed are shown in Figures 6 and 6; (a) is the XRD graph of the ZSM-5 molecular sieve with the template removed and the ZSM-5 molecular sieve without the template removed obtained in Example 6 and Comparative Example 6, and (b) is the thermogravimetric graph of the ZSM-5 molecular sieve with the template removed obtained in Example 6. Figure 5 As can be seen in (b), the ZSM-5 molecular sieve without the template has no obvious weight loss peak after 300°C, proving that the template can be completely removed by flame calcination.

[0083] Figure 6 The XRD graph and thermogravimetric graph of the S-1 molecular sieve with the template removed; wherein (a) is the XRD graph of the S-1 molecular sieve with the template removed obtained in Example 7 and Comparative Example 7 and the S-1 molecular sieve without the template removed, and (b) is the thermogravimetric graph of the S-1 molecular sieve with the template removed obtained in Example 7. Figure 6 As can be seen in (b), the S-1 molecular sieve without the template has no obvious weight loss peak after 300°C, proving that the template can be completely removed by flame calcination.

[0084] Figure 7The catalytic test performance comparison chart of the SAPO-34-block molecular sieve with the template removed obtained in Example 2 and the SAPO-34-block molecular sieve with the template removed obtained in Comparative Example 2 for methanol to olefins (MTO) reaction. The specific operation of the MTO reaction is as follows: First, 300 mg of solid catalyst is loaded into a quartz reaction tube, activated for 90 minutes at 500°C and a nitrogen flow rate of 30 mL / min, and then the temperature is lowered to the catalytic reaction temperature of 450°C to start the catalytic reaction. Nitrogen is used as a carrier gas, and nitrogen is passed into methanol, and raw methanol is continuously introduced into the reactor. By controlling the carrier gas flow rate (15 mL / min) and the temperature of methanol (40°C), the mass space velocity is controlled to be 2h -1 The reaction products were analyzed online using a gas chromatograph (FULIGC9790 II) equipped with a hydrogen ion flame detector (FID) and a Plot-Q column (Kromat, KB-PLOT / Q, with dimensions of 30 m × 320 μm × 10 μm).

[0085] from Figure 7 It can be seen that the SAPO-34-block molecular sieve without calcination treatment has almost no catalytic performance for methanol to olefins. This is because the organic template exists in the pores of the SAPO-34-block molecular sieve, and the reactant methanol cannot enter the interior of the molecular sieve and contact the acidic sites, and no reaction can occur. The catalyst life of the SAPO-34-block molecular sieve obtained in Example 2 without the template is almost the same as that of the SAPO-34-block molecular sieve obtained in Comparative Example 2 without the template, and the diene yield is comparable to that of the SAPO-34-block molecular sieve obtained in Comparative Example 2 without the template.

[0086] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art should understand that other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for rapidly removing a molecular sieve template, characterized in that: The following steps are involved: The molecular sieve containing the template is flame calcined by using a flame spray gun, wherein the temperature of the outer flame of the flame spray gun is 700-800°C.

2. The method according to claim 1, characterized in that: The template agent is selected from one or more of organic ammonium, quaternary ammonium salt and metal organic complex.

3. The method according to claim 1, characterized in that The molecular sieve is a non-metallic molecular sieve.

4. The method according to claim 1 or 3, characterized in that: The molecular sieve is one or more selected from pure silicon molecular sieve, silicon aluminum molecular sieve, silicon aluminum phosphate molecular sieve and aluminum phosphate molecular sieve.

5. The method according to claim 1, characterized in that The content of the template in the molecular sieve is 5-30wt%.

6. The method according to claim 1, characterized in that The molecular sieve is used in an amount of 0.1 to 1 g.

7. The method according to claim 1, characterized in that The molecular sieve is dried.

8. The method according to claim 7, characterized in that The drying treatment method is selected from one or more of heating drying, freeze drying and supercritical drying.

9. The method according to claim 1, characterized in that: The outer flame of the flame spray gun is in direct contact with the molecular sieve.

10. The method according to claim 1, characterized in that The flame calcination treatment time is 1 to 5 minutes.

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