Nickel-based molecular sieve catalyst prepared by ammonia distillation / in-situ synthesis method and preparation method thereof

Abstract

The invention relates to the technical field of molecular sieve catalyst preparation, and is a nickel-based molecular sieve catalyst prepared by an ammonia evaporation / in-situ synthesis method and a preparation method thereof. The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained by the preparation method of the invention has high dispersion of the active component nickel in the molecular sieve, thereby increasing the active surface area, and the nickel is relatively evenly dispersed, without clogging the internal pores of the molecular sieve, thereby greatly improving the activity of the catalyst. When applied to a methanol-coupled light hydrocarbon to olefin reaction system, the catalyst increases the yield of the product olefins, increases the stability, and the performance of the regenerated catalyst is comparable to that of the fresh catalyst. At the same time, the preparation cost is low, the preparation process is simple, and the problems of easy carbon deposition and deactivation, low product yield, and poor catalyst regeneration performance existing in existing metal-loaded molecular sieve catalysts can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieve catalyst preparation, in particular to a nickel-based molecular sieve catalyst prepared by an ammonia distillation / in-situ synthesis method and a preparation method thereof. Background Art

[0002] ZSM-5 zeolite molecular sieve has a three-dimensional cross-shaped "Z" pore structure. Due to its suitable pore and acid properties and good anti-coking ability, this catalyst is often used as the main active component or carrier of the catalyst. However, the microporous structure and large particle size of the ZSM-5 molecular sieve make it difficult for methanol molecules to contact the reaction center and the product to diffuse. In addition, its acid distribution is uneven, which easily produces a large amount of non-target products and rapidly forms carbon deposits, resulting in a shortened catalyst life. In order to improve the stability and activity of the catalyst and at the same time increase the selectivity and yield of light olefins, the in-situ synthesis method is currently often used to load metals on the ZSM-5 molecular sieve. This can improve its mass transfer properties and adjust its acid properties, thereby improving its catalytic performance.

[0003] Light olefins are important basic raw materials for the petrochemical industry. Their downstream products include polyethylene (PE), ethylene glycol, ethylene oxide, styrene, and polyvinyl chloride (PVC), which are used in industries such as packaging, agriculture, construction, electronics, machinery, and the automotive industry. Currently, there are three main methods for producing light olefins: petrochemicals, coal chemical industry, and natural gas synthesis. Among them, catalytic cracking of petroleum to produce light olefins is the most common production method.

[0004] In recent years, the production of light olefins has largely relied on cracking C3 to C12 light hydrocarbons (light hydrocarbons and naphtha). However, the light hydrocarbon-to-olefins reaction is endothermic, associated with high energy consumption, low yields, and high temperatures, hindering its development. Therefore, addressing the efficient utilization of light hydrocarbons is crucial. Besides catalytic cracking of light hydrocarbons to produce ethylene, the most successful non-petroleum-based routes to produce light olefins are the MTO and MTP processes, using methanol as a feedstock. Methanol can be produced from coal, natural gas, or biomass. MTO technology primarily produces a mixture of light olefins, including ethylene and propylene, while MTP technology primarily produces propylene. Because methanol-to-olefins is a highly exothermic reaction with adiabatic temperature rises exceeding 400°C, it places very high demands on the heat exchange of fixed-bed reactors. Therefore, the mixed feedstock of methanol and light hydrocarbons to produce light olefins not only allows for thermal coupling of the methanol and light hydrocarbon reactions but also allows for the full utilization of lower-value-added alkanes, potentially improving the selectivity or yield of light olefins and extending the catalyst's single-pass life.

[0005] Chinese patent document CN106745050A discloses a method for in-situ synthesis of precious metal-loaded ZSM-5 molecular sieves. The method comprises the following steps: stirring and mixing an aluminum source, water, a template solution, and a precious metal salt solution; adding a silicon source; stirring and mixing the mixture; crystallizing the mixture in a reactor to obtain a crystal; and washing and drying the crystals to obtain the precious metal-loaded molecular sieve.

[0006] Chinese patent document CN113731478A discloses a Zn-ZSM-5 / ZSM-11 catalyst and a preparation method thereof, which utilizes a one-step in-situ synthesis method, comprising: (1) adding a silicon source and an alkali raw material to water to obtain a mixed solution A; (2) adding an aluminum source, a template, and a zinc source to the mixed solution A, and refluxing the reaction system at 80°C to 150°C for 2 to 8 hours to obtain a mixed solution B; (3) subjecting the mixed solution B to a crystallization reaction at 130°C to 170°C for 18 to 96 hours to obtain a mixed solution C; (4) cooling the mixed solution C to room temperature, filtering, washing, and drying, and subjecting the obtained solid product to a first calcination treatment to obtain a catalyst precursor; and (5) subjecting the catalyst precursor to ammonium exchange, and subjecting the exchanged product to a second calcination treatment to obtain a Zn-ZSM-5 / ZSM-11 catalyst. While the one-step reduction method for metal loading simplifies the traditional zeolite molecular sieve-loaded metal catalyst preparation process by eliminating the calcination and H2 reduction steps, reducing operating costs, and producing a molecular sieve significantly superior to metal-loaded molecular sieves prepared by the traditional impregnation method, this process, however, prevents the metal active components from being completely and evenly spread on the support, causing the active metal particles on the support to aggregate, resulting in reduced catalyst activity and stability. Summary of the Invention

[0007] The present invention provides a nickel-based molecular sieve catalyst prepared by an ammonia evaporation / in-situ synthesis method and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of low catalytic activity and low stability of existing nickel-based catalysts.

[0008] One of the technical solutions of the present invention is achieved by the following measures: a nickel-based molecular sieve catalyst prepared by an ammonia distillation / in-situ synthesis method is obtained by the following method:

[0009] S1, adding silicon source and alkali source to deionized water in sequence and stirring evenly to form solution a;

[0010] S2, adding aluminum source, ZSM-5 seed crystals and template agent to deionized water in sequence and stirring to form solution b;

[0011] S3, adding solution b dropwise to solution a, stirring and mixing until uniform, to form gel solution A;

[0012] S4, dissolving the nickel salt in deionized water to obtain a nickel salt aqueous solution, and adjusting the pH of the nickel salt aqueous solution with ammonia water to obtain a nickel ammonia solution B;

[0013] S5, adding nickel ammonia solution B to gel solution A in a sealed manner with stirring, and then heating to evaporate ammonia to obtain a mixed gel solution C;

[0014] S6, crystallizing the mixed gel solution C, filtering the obtained reaction product, washing it to neutrality, and then drying and calcining it once to obtain a catalyst precursor;

[0015] S7, immersing the obtained catalyst precursor in an ammonium salt solution for ammonium exchange, filtering and washing the impregnated catalyst precursor until the pH is 5 to 8, and then drying and calcining it twice to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0016] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0017] The molar ratio of the silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water is (30 to 290): (0.4 to 28): 1: (5.5 to 31): (2500 to 6500).

[0018] The mass ratio of the ZSM-5 seed crystal to the template is 1:(0.5 to 5.0).

[0019] The silicon source is one or more of silica sol, silica gel, tetraethyl orthosilicate, sodium silicate nonahydrate and fumed silica.

[0020] The alkali source is one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide.

[0021] The aluminum source is one or more of aluminum sulfate, sodium metaaluminate, aluminum chloride, aluminum nitrate, aluminum isopropoxide and aluminum oxide.

[0022] The template agent is one or more of n-butylamine, ethylenediamine, tetrabutylammonium hydroxide and hexadecyltrimethylammonium bromide.

[0023] The molar ratio of silicon to aluminum in the ZSM-5 seed crystals is 30, 150 or 300.

[0024] The nickel salt is one of Ni(NO3)2·6H2O and NiSO4·6H2O.

[0025] In the above step S4, the pH value of the nickel salt aqueous solution is adjusted to 9 to 12 with ammonia water having a mass concentration of 20% to 30%, thereby obtaining a nickel ammonia solution B having a nickel concentration of 0.1 mol / L to 4.0 mol / L.

[0026] In the above step S5, during the closed stirring, the temperature is 20°C to 40°C and the time is 2 hours to 10 hours; during the heating and ammonia evaporation, the temperature is 50°C to 100°C and the time is 1 hour to 6 hours, and the pH value of the mixed gel solution C is 5 to 8.

[0027] In the above steps S6 and S7, during the first and second calcinations, the calcination temperatures are both 530° C. to 600° C., and the calcination times are both 3 h to 10 h.

[0028] In the above step S7, the concentration of the ammonium salt solution is 1 mol / L to 5 mol / L, the ammonium salt is one of ammonium chloride and ammonium nitrate, the ammonium exchange temperature is 30°C to 60°C, the ammonium exchange time is 3h to 12h, and the number of immersions is 1 to 2 times.

[0029] In the above step S6, the crystallization reaction temperature is 100° C. to 220° C., and the reaction time is 24 h to 96 h.

[0030] In the above step S6, the crystallization reaction temperature is 140° C. to 180° C., and the reaction time is 48 h to 72 h.

[0031] In the above steps S6 and S7, during the primary and secondary calcinations, the heating rate is controlled to be 1° C. / min to 5° C. / min, the drying time is 50° C. to 180° C., and the drying temperature is 1 h to 24 h.

[0032] In the above steps S6 and S7, during the primary and secondary calcinations, the heating rate is controlled to be 2°C / min to 3°C / min, the drying time is 90°C to 150°C, and the drying temperature is 3h to 12h.

[0033] In the above step S3, the stirring temperature is 10° C. to 50° C., and the stirring time is 2 h to 10 h.

[0034] In the above step S3, the stirring temperature is 20° C. to 30° C., and the stirring time is 2 h to 5 h.

[0035] The second technical solution of the present invention is achieved by the following measures: a method for preparing a nickel-based molecular sieve catalyst prepared by an ammonia distillation / in-situ synthesis method is carried out as follows:

[0036] S1, adding silicon source and alkali source to deionized water in sequence and stirring evenly to form solution a;

[0037] S2, adding aluminum source, ZSM-5 seed crystals and template agent to deionized water in sequence and stirring evenly to form solution b;

[0038] S3, slowly adding solution b dropwise to solution a, stirring vigorously to mix evenly, to form gel solution A;

[0039] S4, dissolving the nickel salt in deionized water to obtain a nickel salt aqueous solution, and adjusting the pH of the nickel salt aqueous solution with ammonia water to obtain a nickel ammonia solution B;

[0040] S5, adding nickel ammonia solution B to gel solution A in a sealed manner with stirring, and then heating to evaporate ammonia to obtain a mixed gel solution C;

[0041] S6, crystallizing the mixed gel solution C, filtering the obtained reaction product, washing it to neutrality, and then drying and calcining it once to obtain a catalyst precursor;

[0042] S7, immersing the obtained catalyst precursor in an ammonium salt solution for ammonium exchange, filtering and washing the impregnated catalyst precursor until the pH is 5 to 8, and then drying and calcining it twice to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0043] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained by the preparation method of the present invention has high dispersion of the active component nickel in the molecular sieve, which increases the active surface area. The nickel is dispersed more evenly and will not block the internal pores of the molecular sieve, thereby greatly improving the activity of the catalyst. When applied to a methanol-coupled light hydrocarbon to olefin reaction system, the yield of the product olefins is increased, the stability is enhanced, and the performance of the regenerated catalyst is equivalent to that of the fresh catalyst. At the same time, the preparation cost is low and the preparation process is simple, and the problems of easy carbon deposition and deactivation, low product yield, and poor catalyst regeneration performance existing in existing metal-loaded molecular sieve catalysts can be effectively solved. DETAILED DESCRIPTION

[0044] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals commonly known in the prior art; unless otherwise specified, percentages in the present invention are by mass; unless otherwise specified, solutions in the present invention are all aqueous solutions in which the solvent is water; for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution.

[0045] The present invention will be further described below in conjunction with the embodiments:

[0046] Example 1: The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method was obtained by the following method:

[0047] S1, adding silicon source and alkali source to deionized water in sequence and stirring evenly to form solution a;

[0048] S2, adding aluminum source, ZSM-5 seed crystals and template agent to deionized water in sequence and stirring to form solution b;

[0049] S3, adding solution b dropwise to solution a, stirring and mixing until uniform, to form gel solution A;

[0050] S4, dissolving the nickel salt in deionized water to obtain a nickel salt aqueous solution, and adjusting the pH of the nickel salt aqueous solution with ammonia water to obtain a nickel ammonia solution B;

[0051] S5, adding nickel ammonia solution B to gel solution A in a sealed manner with stirring, and then heating to evaporate ammonia to obtain a mixed gel solution C;

[0052] S6, crystallizing the mixed gel solution C, filtering the obtained reaction product, washing it to neutrality, and then drying and calcining it once to obtain a catalyst precursor;

[0053] S7, immersing the obtained catalyst precursor in an ammonium salt solution for ammonium exchange, filtering and washing the impregnated catalyst precursor until the pH is 5 to 8, and then drying and calcining it twice to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0054] Compared with the prior art, the nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained by the preparation method of the present invention can load the active ingredient, metallic nickel, in the molecular sieve while synthesizing the molecular sieve in situ, and effectively adjust the size of the nickel crystals, reduce the size of the nickel crystals, make the nickel crystals highly dispersed inside the molecular sieve, strengthen the interaction between the metal and the carrier, and thus improve the stability of the catalyst.

[0055] Example 2: As an optimization of the above example, the molar ratio of the silicon source (calculated as SiO2), the alkali source (calculated as Na2O), the aluminum source (calculated as Al2O3), the template and deionized water is (30 to 290): (0.4 to 28): 1: (5.5 to 31): (2500 to 6500).

[0056] Example 3: As an optimization of the above example, the mass ratio of ZSM-5 seed crystals to template is 1:(0.5 to 5.0).

[0057] Example 4: As an optimization of the above example, the silicon source is one or more of silica sol, silica gel, tetraethyl orthosilicate, sodium silicate nonahydrate and fumed silica.

[0058] Example 5: As an optimization of the above example, the alkali source is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0059] Example 6: As an optimization of the above example, the aluminum source is one or more of aluminum sulfate, sodium aluminate, aluminum chloride, aluminum nitrate, aluminum isopropoxide and aluminum oxide.

[0060] Example 7: As an optimization of the above example, the template agent is one or more of n-butylamine, ethylenediamine, tetrabutylammonium hydroxide and hexadecyltrimethylammonium bromide.

[0061] Example 8: As an optimization of the above example, the molar ratio of silicon to aluminum in the ZSM-5 seed crystals is 30, 150 or 300.

[0062] Example 9: As an optimization of the above example, the nickel salt is one of Ni(NO3)2·6H2O and NiSO4·6H2O.

[0063] Example 10: As an optimization of the above example, in step S4, the pH value of the nickel salt aqueous solution is adjusted to 9 to 12 with ammonia water having a mass concentration of 20% to 30%, to obtain a nickel ammonia solution B with a nickel concentration of 0.1 mol / L to 4.0 mol / L.

[0064] Example 11: As an optimization of the above example, in step S5, during the closed stirring, the temperature is 20°C to 40°C, and the time is 2 hours to 10 hours; during the heating to evaporate ammonia, the temperature is 50°C to 100°C, and the time is 1 hour to 6 hours, and the pH value of the mixed gel solution C is 5 to 8.

[0065] Example 12: As an optimization of the above example, in steps S6 and S7, the roasting temperature during the first roasting and the second roasting is 530° C. to 600° C., and the roasting time is 3 h to 10 h.

[0066] Example 13: As an optimization of the above example, in step S7, the concentration of the ammonium salt solution is 1 mol / L to 5 mol / L, the ammonium salt is one of ammonium chloride and ammonium nitrate, the ammonium exchange temperature is 30°C to 60°C, the ammonium exchange time is 3h to 12h, and the number of immersions is 1 to 2 times.

[0067] Example 14: As an optimization of the above example, in step S6, the crystallization reaction temperature is 100°C to 220°C, and the reaction time is 24h to 96h.

[0068] Example 15: As an optimization of the above example, in step S6, the crystallization reaction temperature is 140°C to 180°C, and the reaction time is 48h to 72h.

[0069] Example 16: As an optimization of the above example, in steps S6 and S7, during the first and second roasting, the heating rate is controlled to be 1°C / min to 5°C / min, the drying time is 50°C to 180°C, and the drying temperature is 1h to 24h.

[0070] Example 17: As an optimization of the above example, in steps S6 and S7, during the first and second roasting, the heating rate is controlled to be 2°C / min to 3°C / min, the drying time is 90°C to 150°C, and the drying temperature is 3h to 12h.

[0071] Example 18: As an optimization of the above example, in step S3, the stirring temperature is 10°C to 50°C, and the stirring time is 2h to 10h.

[0072] Example 19: As an optimization of the above example, in step S3, the stirring temperature is 20°C to 30°C, and the stirring time is 2h to 5h.

[0073] Example 20:

[0074] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0075] S1, add silicon source (silica sol) and alkali source (sodium hydroxide) to deionized water in sequence and stir evenly to form solution a;

[0076] S2, adding an aluminum source (aluminum sulfate), ZSM-5 seed crystals (silicon-aluminum ratio of 30) and a template (n-butylamine) to deionized water in sequence, stirring evenly to form solution b;

[0077] S3, slowly adding solution b dropwise to solution a, vigorously stirring at 10°C for 2 h to mix evenly, to form gel solution A; wherein the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 30:0.4:1:5.5:2500, and the mass ratio of ZSM-5 seed crystals to template is 1:0.5;

[0078] S4, dissolving nickel salt (Ni(NO3)2·6H2O) in deionized water to obtain a nickel salt aqueous solution, adjusting the pH of the nickel salt aqueous solution to 9 with 20% ammonia water to obtain a nickel ammonia solution B with a nickel concentration of 0.1 mol / L;

[0079] S5, adding nickel ammonia solution B to gel solution A, stirring in a sealed container at 20°C for 2 hours, and then heating at 50°C for 1 hour to evaporate ammonia until the pH value of the solution is 5, thereby obtaining a mixed gel solution C;

[0080] S6, crystallizing the mixed gel solution C at 100° C. for 24 hours, filtering and washing the obtained reaction product until it is neutral, then drying it at 50° C. for 1 hour, and finally calcining it at 530° C. at a heating rate of 1° C. / min for 3 hours to obtain a catalyst precursor;

[0081] S7, immersing the obtained catalyst precursor in an ammonium salt (ammonium chloride) solution with a concentration of 1 mol / L at 30°C for ammonium exchange for 3 to 12 hours, repeating the immersion once, filtering and washing the impregnated catalyst precursor until the pH reaches 5, then drying at 50°C for 1 hour, and finally calcining it for a second time at 530°C at a heating rate of 1°C / min for 3 hours to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0082] Example 21:

[0083] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0084] S1, add silicon source (silica gel) and alkali source (potassium hydroxide) to deionized water in sequence and stir evenly to form solution a;

[0085] S2, adding an aluminum source (sodium metaaluminate), ZSM-5 seed crystals (silicon-aluminum ratio of 150) and a template (ethylenediamine) to deionized water in sequence, stirring evenly to form solution b;

[0086] S3, slowly adding solution b dropwise to solution a, vigorously stirring at 50°C for 10 h to mix evenly, to form gel solution A; wherein the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 290:28:1:31:6500, and the mass ratio of ZSM-5 seed crystals to template is 1:5.0;

[0087] S4, dissolving nickel salt (NiSO4·6H2O) in deionized water to obtain a nickel salt aqueous solution, adjusting the pH of the nickel salt aqueous solution to 12 with 30% ammonia water to obtain a nickel ammonia solution B with a nickel concentration of 4.0 mol / L;

[0088] S5, adding nickel ammonia solution B to gel solution A, stirring in a sealed container at 40°C for 10 hours, and then heating at 100°C to evaporate ammonia for 6 hours until the pH value of the mixed solution reaches 8, thereby obtaining a mixed gel solution C;

[0089] S6, crystallizing the mixed gel solution C at 220° C. for 96 hours, filtering and washing the obtained reaction product until it is neutral, then drying it at 180° C. for 24 hours, and finally calcining it at 600° C. at a heating rate of 5° C. / min for 10 hours to obtain a catalyst precursor;

[0090] S7, immersing the obtained catalyst precursor in an ammonium salt (ammonium nitrate) solution with a concentration of 5 mol / L at 60°C for ammonium exchange for 12 hours, repeating the immersion twice, filtering and washing the impregnated catalyst precursor until the pH reaches 8, then drying at 180°C for 24 hours, and finally calcining it for a second time at 600°C with a heating rate of 5°C / min for 10 hours to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0091] Example 22:

[0092] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0093] S1, add silicon source (tetraethyl orthosilicate) and alkali source (calcium hydroxide) to deionized water in sequence and stir evenly to form solution a;

[0094] S2, adding an aluminum source (aluminum chloride), ZSM-5 seed crystals (silicon-aluminum ratio of 300) and a template (tetrabutylammonium hydroxide) to deionized water in sequence, stirring evenly to form solution b;

[0095] S3, slowly adding solution b dropwise to solution a, vigorously stirring at 50°C for 10 h to mix evenly, to form gel solution A; wherein the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 200:15:1:20:5000, and the mass ratio of ZSM-5 seed crystals to template is 1:3;

[0096] S4, dissolving nickel salt (Ni(NO3)2·6H2O) in deionized water to obtain a nickel salt aqueous solution, adjusting the pH of the nickel salt aqueous solution to 11 with 25% ammonia water to obtain a nickel ammonia solution B with a nickel concentration of 2 mol / L;

[0097] S5, adding nickel ammonia solution B to gel solution A, stirring in a sealed container at 30°C for 6 hours, and then heating at 70°C to evaporate ammonia for 3 hours until the pH value of the mixed solution is 7, thereby obtaining a mixed gel solution C;

[0098] S6, crystallizing the mixed gel solution C at 150° C. for 50 h, filtering and washing the obtained reaction product until neutral, then drying it at 100° C. for 15 h, and finally calcining it at 570° C. at a heating rate of 3° C. / min for 6 h to obtain a catalyst precursor;

[0099] S7, immersing the obtained catalyst precursor in an ammonium salt (ammonium chloride) solution with a concentration of 3 mol / L at 45°C for ammonium exchange for 9 hours, repeating the immersion twice, filtering and washing the impregnated catalyst precursor until the pH is 5 to 8, then drying at 100°C for 15 hours, and finally calcining it for a second time at 570°C at a heating rate of 3°C / min for 6 hours to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0100] Example 23:

[0101] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0102] S1, add 190g of ethyl orthosilicate and 12ml of 7mol / L NaOH to 300g of deionized water, and stir at room temperature to form solution a;

[0103] S2, 0.987 g of sodium aluminate, 10 g of ZSM-5 seed crystals and 11.74 g of tetrabutylammonium hydroxide were added to 100 g of deionized water in sequence, and stirred at room temperature to form solution b;

[0104] S3, slowly add solution b dropwise to solution a, and vigorously stir at 30 °C for 5 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 152:8:1:7.53:3703);

[0105] S4, taking 0.5 g of Ni(NO3)2·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0106] S5, adding nickel ammonia solution B to gel solution A at 30°C, sealing and stirring for 8 hours, then heating and distilling ammonia at 70°C and stirring for 6 hours until the solution pH is 6, to obtain mixed gel solution C;

[0107] S6, transferring the mixed gel solution C to a stainless steel hydrothermal synthesis reactor, heating at 160°C for crystallization reaction for 48 hours, filtering and washing the mixed solution in the reactor until it is neutral, drying at 100°C for 8 hours, and finally calcining at 550°C for 2 hours to obtain a catalyst precursor;

[0108] S7. Weigh 19 g of the catalyst precursor and add it to 500 mL of a 1 mol / L NH4Cl solution. Stir in a 60°C water bath for 2 h. Then, add deionized water, filter, and wash until the pH is 6 to 7. Place the filtered filter cake back into the NH4Cl solution and repeat the above steps once. Then, dry it in an oven at 100°C for 8 h, then calcinate it again in a muffle furnace at 550°C for 2 h to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0109] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 23 of the present invention was applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0110] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 23 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0111] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the inlet of the fixed bed reactor at a mass ratio of 3:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 500 °C, a pressure of 1.5 MPa (N2), and a total mass space velocity (WHSV) of 0.5 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0112] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 48.9%, and the reaction time reached 960h when the methanol conversion rate was 100%.

[0113] Example 24:

[0114] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0115] S1, add 500g of tetraethyl orthosilicate and 24ml of 18mol / L NaOH to 500g of deionized water in sequence, and stir evenly at room temperature to form solution a;

[0116] S2, 1.968g of sodium aluminate, 23.7g of ZSM-5 seed crystals and 15.8g of n-butylamine were added to 150g of deionized water in sequence, and stirred at room temperature to form solution b;

[0117] S3, slowly add solution b dropwise to solution a, and vigorously stir at 25 °C for 4 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 200:19:1:18:3009.26);

[0118] S4, taking 1.02 g of Ni(NO3)2·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0119] Subsequent steps S5 to S7 are the same as those in Example 23 of the present invention.

[0120] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 24 of the present invention was applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0121] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 24 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0122] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 480 °C, a pressure of 0.5 MPa (N2), and a total mass space velocity (WHSV) of 1.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0123] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 57.8%, and the reaction time reached 1080h when the methanol conversion rate was 100%.

[0124] Example 25:

[0125] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0126] S1, add 42.5g of fumed silica and 12ml of 2.5mol / L NaOH to 100g of deionized water, and stir at room temperature to form solution a;

[0127] S2, 2.25 g Al(NO3)3·9H2O, 4.25 g ZSM-5 seed crystals and 3.606 g ethylenediamine were added to 50 g deionized water in sequence, and stirred at room temperature to form solution b;

[0128] S3, slowly add solution b dropwise to solution a and vigorously stir at 30°C for 3 h to mix evenly to form gel solution A3 (the molar ratio of silicon source (in terms of SiO2), alkali source (in terms of Na2O), aluminum source (in terms of Al2O3), template and deionized water in gel solution A is 235.8:5:1:10:2777.78).

[0129] S4, taking 1.98 g of Ni(NO3)2·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0130] Subsequent steps S5, S6 and S7 are the same as those in Example 23 of the present invention.

[0131] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 25 of the present invention is applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0132] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 25 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0133] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 480 °C, a pressure of 0.5 MPa (N2), and a total mass space velocity (WHSV) of 1.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0134] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 45.42%, and the reaction time reached 950h when the methanol conversion rate was 100%.

[0135] Example 26:

[0136] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0137] S1, add 430g of tetraethyl orthosilicate and 30ml of 8mol / L NaOH to 600g of deionized water in sequence, and stir at room temperature to form solution a;

[0138] S2, 1.968g of sodium aluminate, 12.456g of ZSM-5 seed crystals and 62.28g of tetrabutylammonium hydroxide were added to 415g of deionized water in sequence, and stirred at room temperature to form solution b;

[0139] S3, slowly add solution b dropwise to solution a and vigorously stir at 30°C for 3 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 172:22:1:20:4699.07);

[0140] S4, taking 0.90 g of NiSO4·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0141] S5, adding nickel ammonia solution B to gel solution A at 40°C, sealing and stirring for 4 hours, then heating and distilling ammonia at 90°C and stirring for 4 hours until the solution pH is 6, to obtain mixed gel solution C;

[0142] S6, transferring the mixed gel solution C to a stainless steel hydrothermal synthesis reactor, heating at 140°C for crystallization reaction for 72 hours, filtering and washing the mixed solution in the reactor until it is neutral, drying at 90°C for 12 hours, and finally calcining at 530°C for 4 hours to obtain a catalyst precursor;

[0143] S7. Weigh 19 g of the catalyst precursor and add it to 500 mL of a 1 mol / L NH4Cl solution. Stir in a 40°C water bath for 4 hours. Then, add deionized water, filter, and wash until the pH is 6 to 7. Place the filtered filter cake back into the NH4Cl solution and repeat the above steps once. Then, dry it in an oven at 90°C for 12 hours and calcine it again in a muffle furnace at 530°C for 4 hours to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0144] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 26 of the present invention was applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0145] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 26 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0146] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 480 ° C, a pressure of 1.0 MPa (N2), and a total mass space velocity (WHSV) of 1.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0147] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 58.9%, and the reaction time reached 1104h when the methanol conversion rate was 100%.

[0148] Example 27:

[0149] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0150] S1, add 52.325g of ethyl orthosilicate and 12ml of 7mol / L NaOH to 200g of deionized water, and stir at room temperature to form solution a;

[0151] S2, add 4g Al2(SO4)3·18H2O, 4.28g ZSM-5 seed crystals and 8.56g tetrabutylammonium hydroxide to 100g deionized water in sequence, and stir evenly at room temperature to form solution b;

[0152] S3, slowly add solution b dropwise to solution a, and vigorously stir at 20°C for 5 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 41.86:7:1:5.5:2777.78).

[0153] S4, taking 1.98 g of Ni(NO3)2·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0154] Subsequent steps S5, S6 and S7 are the same as those in Example 23 of the present invention.

[0155] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 27 of the present invention was applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0156] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 27 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0157] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 500 °C, a pressure of 0.5 MPa (N2), and a total mass space velocity (WHSV) of 2.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0158] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 59.1%, and when the methanol conversion rate was above 95%, the reaction time reached 1224h.

[0159] Example 28:

[0160] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0161] S1, add 51.12g of fumed silica and 17ml of 3mol / L NaOH to 300g of deionized water in sequence, and stir evenly at room temperature to form solution a;

[0162] S2, 2.26 g Al(NO3)3·9H2O, 10 g ZSM-5 seed crystals and 9.48 g hexadecyltrimethylammonium bromide were added to 50 g deionized water in sequence, and stirred at room temperature to form solution b;

[0163] S3, slowly add solution b dropwise to solution a, and vigorously stir at 30°C for 2 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 283.62:8.5:1:8.67:6481.48);

[0164] S4, taking 0.90 g of NiSO4·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0165] S5, adding nickel ammonia solution B to gel solution A at 20°C, sealing and stirring for 10 hours, then heating and distilling ammonia at 50°C and stirring for 6 hours until the solution pH is 8, to obtain mixed gel solution C;

[0166] S6, transferring the mixed gel solution C to a stainless steel hydrothermal synthesis reactor, heating at 140°C for crystallization reaction for 72 hours, filtering and washing the mixed solution in the reactor until it is neutral, drying at 150°C for 4 hours, and finally calcining at 570°C for 4 hours to obtain a catalyst precursor;

[0167] S7. Weigh 19 g of the catalyst precursor and add it to 500 mL of a 1 mol / L NH4Cl solution. Stir in a 60°C water bath for 2 h. Then, add deionized water, filter, and wash until the pH is 6 to 7. Place the filtered filter cake back into the NH4Cl solution and repeat the above steps once. Then, dry it in an oven at 150°C for 4 h, then calcine it again in a muffle furnace at 570°C for 4 h to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0168] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 28 of the present invention was applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0169] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 28 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0170] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 480 °C, a pressure of 0.5 MPa (N2), and a total mass space velocity (WHSV) of 1.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0171] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 56.7%, and the reaction time reached 1080h when the methanol conversion rate was 100%.

[0172] Example 29:

[0173] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0174] S1, add 183g silica sol (SiO2 content 30%) and 12ml 8mol / L NaOH to 400g deionized water in sequence, and stir evenly at room temperature to form solution a;

[0175] S2, 4.5 g Al(NO3)3·9H2O, 30 g ZSM-5 seed crystals and 10.98 g ethylenediamine were added to 200 g deionized water in sequence, and stirred at room temperature to form solution b;

[0176] S3, slowly add solution b dropwise to solution a, and vigorously stir at 30°C for 5 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 152.3:8:1:30.45:5555.56);

[0177] S4, taking 1.8 g of NiSO4·6H2O as nickel salt, adding 20 ml of deionized water, adding 20% ​​ammonia water dropwise to the nickel aqueous solution, adjusting the pH value of the nickel salt aqueous solution to 11, and stirring to prepare nickel ammonia solution B;

[0178] S5, adding nickel ammonia solution B to gel solution A at 40°C, sealing and stirring for 4 hours, then heating and evaporating ammonia at 100°C and stirring for 2 hours until the solution pH is 8, to obtain mixed gel solution C;

[0179] S6, transferring the mixed gel solution C to a stainless steel hydrothermal synthesis reactor, heating at 140°C for crystallization reaction for 72 hours, filtering and washing the mixed solution in the reactor until it is neutral, drying at 120°C for 6 hours, and finally calcining at 570°C for 4 hours to obtain a catalyst precursor;

[0180] S7. Weigh 19 g of the catalyst precursor and add it to 500 mL of a 1 mol / L NH4Cl solution. Stir in a 60°C water bath for 2 h. Then, add deionized water, filter, and wash until the pH is 6 to 7. Place the filtered filter cake back into the NH4Cl solution and repeat the above steps once. Then, dry it in an oven at 120°C for 6 h, and calcine it again in a muffle furnace at 570°C for 4 h to obtain a nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0181] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 29 of the present invention was applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0182] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 29 of the present invention and the 75 wt % Al 2 O 3 carrier were tableted or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0183] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the inlet of the fixed bed reactor at a mass ratio of 3:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 500 °C, a pressure of 1.5 MPa (N2), and a total mass space velocity (WHSV) of 0.5 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0184] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 48.9%, and the reaction time reached 960h when the methanol conversion rate was 100%.

[0185] Example 30:

[0186] The nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method is obtained by the following method:

[0187] S1, add 183g silica sol (SiO2 content 30%) and 12ml 7mol / L NaOH to 170g deionized water in sequence, and stir evenly at room temperature to form solution a;

[0188] S2, add 4 g Al2(SO4)3·18H2O, 10 g ZSM-5 seed crystals and 20 g hexadecyl ammonium bromide to 100 g deionized water in sequence, and stir evenly at room temperature to form solution b;

[0189] S3, slowly add solution b dropwise to solution a and vigorously stir at 25°C for 4 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 152.3:7:1:9.15:2500);

[0190] Subsequent steps S4 to S7 are the same as those in Example 28 of the present invention.

[0191] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 30 of the present invention is applied to the methanol coupling reaction of light hydrocarbons to light olefins. The specific steps are as follows:

[0192] First, the nickel-based molecular sieve catalyst solid particles prepared by the ammonia evaporation / in-situ synthesis method obtained in Example 30 of the present invention and the 75 wt % Al 2 O 3 carrier are pressed into tablets or extruded into strips, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0193] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 420 °C, a pressure of 3.0 MPa (N2), and a total mass space velocity (WHSV) of 2.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0194] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 55.4%, and the reaction time reached 1124h when the methanol conversion rate was 100%.

[0195] Comparative Example 1:

[0196] The nickel-based molecular sieve catalyst is obtained by the following method:

[0197] S1, add 190g of ethyl orthosilicate and 12ml of 7mol / L NaOH to 300g of deionized water, and stir at room temperature to form solution a;

[0198] S2, 0.987 g of sodium aluminate, 0.5 g of Ni(NO3)2·6H2O, 10 g of ZSM-5 seed crystals and 11.74 g of tetrabutylammonium hydroxide were added to 100 g of deionized water in sequence, and stirred at room temperature to form solution b;

[0199] S3, slowly add solution b dropwise to solution a, and vigorously stir at 30°C for 3 h to mix evenly to form gel solution A (the molar ratio of silicon source (calculated as SiO2), alkali source (calculated as Na2O), aluminum source (calculated as Al2O3), template and deionized water in gel solution A is 152.3:8:1:0.28:7.54:3703);

[0200] S4, transferring gel solution A to a stainless steel hydrothermal synthesis reactor, heating at 150°C for crystallization reaction for 36 hours, filtering and washing the mixed solution in the reactor until it is neutral, drying at 120°C for 6 hours, and finally calcining at 550°C for 3 hours to obtain a catalyst precursor;

[0201] S5. Weigh 19 g of the catalyst precursor and add it to 500 mL of a 1 mol / L NH4Cl solution. Stir in a 60°C water bath for 2 h. Then, add deionized water, filter, and wash until the pH is 6 to 7. Place the filtered filter cake back into the NH4Cl solution and repeat the above steps once. Then, dry it in an oven at 120°C for 6 h, and calcine it again in a muffle furnace at 550°C for 4 h to obtain a nickel-based molecular sieve catalyst.

[0202] The nickel-based molecular sieve catalyst obtained in Comparative Example 1 of the present invention is applied to the reaction of methanol coupling with light hydrocarbons to produce light olefins, and the specific steps are as follows:

[0203] First, the nickel-based molecular sieve catalyst solid particles obtained in Comparative Example 1 of the present invention and the 75wt% Al2O3 carrier are pressed into tablets or extruded, crushed and sieved to obtain a catalyst with a particle size of 0.8 cm to 2.0 cm;

[0204] Then, 50 g of catalyst particles were loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the fixed bed reactor at a mass ratio of 1:1 and came into contact with the catalyst bed to undergo a coupled reforming reaction. The process conditions were a reaction temperature of 480 °C, a pressure of 0.5 MPa (N2), and a total mass space velocity (WHSV) of 1.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0205] Finally, the results of methanol coupling light hydrocarbon reforming to enrich low-carbon olefins while taking into account the aromatic hydrocarbon reaction were: the yield of ethylene + propylene + butene was 25.6%, and the reaction time reached 144h when the methanol conversion rate was 100%.

[0206] Example 31:

[0207] The catalytic performance of the nickel-based molecular sieve catalyst prepared by the ammonia distillation / in-situ synthesis method of the present invention and regenerated after being deactivated by the reaction was investigated.

[0208] (1) The specific steps of the catalyst regeneration process are as follows:

[0209] First, the nickel-based molecular sieve catalysts prepared by the ammonia evaporation / in-situ synthesis method of Examples 24 and 26 of the present invention and the nickel-based molecular sieve catalyst of Comparative Example 1, which were deactivated after being applied to the methanol coupling reaction of light hydrocarbons to light olefins, were unloaded from the fixed bed reactor, and the porcelain ball powder was filtered out to leave a catalyst with a particle size of 0.8 cm to 2.0 cm.

[0210] Then, the deactivated nickel-based molecular sieve catalyst particles prepared by the ammonia evaporation / in-situ synthesis method were placed in a fixed bed reactor and regenerated by N2 at a regeneration temperature of 530°C and a regeneration time of 4 hours to obtain the regenerated nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method.

[0211] (2) The regenerated catalyst is used again in the methanol coupling reaction to produce light olefins. The specific steps are as follows:

[0212] 50 g of nickel-based molecular sieve catalyst particles prepared by the ammonia evaporation / in-situ synthesis method after regeneration in Example 24 and Example 26 of the present invention and the nickel-based molecular sieve catalyst particles after regeneration in Comparative Example 1 were respectively taken and loaded into the middle of the reaction tube in the fixed bed reactor. The reaction materials methanol and hydrocracked light naphtha were introduced into the inlet of the fixed bed reactor in a mass ratio of 1:1 and contacted with the catalyst bed to cause a coupled reforming reaction. The process conditions were as follows: reaction temperature of 500 ° C, pressure of 0.5 MPa (N2), and total mass space velocity WHSV = 1.0 h -1 After the reaction is completed, the reaction product is condensed and separated, and samples are collected for chromatographic analysis;

[0213] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method after regeneration in Example 24 of the present invention was again applied to the methanol coupling light hydrocarbon reforming reaction to enrich the production of light olefins while taking into account the aromatic hydrocarbons. The results showed that the yield of ethylene + propylene + butene was 55.4%, and the reaction time reached 960 hours when the methanol conversion rate was 100%.

[0214] The nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method after regeneration in Example 26 of the present invention was again applied to the methanol-coupled light hydrocarbon reforming reaction to enrich the production of light olefins while taking into account the aromatic hydrocarbons. The results showed that the yield of ethylene + propylene + butene was 53.7%, and the reaction time reached 860 hours when the methanol conversion rate was 100%.

[0215] The nickel-based molecular sieve catalyst regenerated in comparative example 1 of the present invention was again applied to the methanol coupling light hydrocarbon reforming to enrich the low-carbon olefins while taking into account the aromatic hydrocarbon reaction results: ethylene + propylene + butene yield was 39.8%, and when the methanol conversion rate was 100%, the reaction time reached 600h.

[0216] Compared to the nickel-based molecular sieve catalyst obtained in Comparative Example 1 of the present invention, the nickel-based molecular sieve catalysts prepared by the ammonia evaporation / in-situ synthesis method obtained in Examples 23 and 30 of the present invention performed better in the coupled reforming reaction of methanol and light hydrocarbons. At reaction temperatures of 400°C to 600°C, the gas-phase olefin (ethylene + propylene + butene) yield was 45% to 60%, and the catalyst was stable for 850 to 1230 hours. After the reaction, the catalyst was regenerated and used in the coupled reforming reaction of methanol and light hydrocarbons. The methanol conversion rate remained at 100%, and the olefin yield was not reduced. The catalytic performance of the regenerated catalyst was comparable to that of the fresh catalyst (the catalyst used for the first time).

[0217] In summary, the nickel-based molecular sieve catalyst prepared by the ammonia evaporation / in-situ synthesis method obtained by the preparation method of the present invention has high dispersion of the active ingredient nickel in the molecular sieve, which increases the active surface area. The nickel is dispersed more evenly and will not clog the internal pores of the molecular sieve, thereby greatly improving the activity of the catalyst. When applied to a methanol-coupled light hydrocarbon to olefin reaction system, the yield of the product olefins is increased, the stability is increased, and the performance of the regenerated catalyst is comparable to that of the fresh agent. At the same time, the preparation cost is low and the preparation process is simple, which can effectively solve the problems of easy carbon deposition and deactivation, low product yield, and poor catalyst regeneration performance of existing metal-loaded molecular sieve catalysts.

[0218] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by an ammonia distillation / in-situ synthesis method, characterized in that Obtained as follows: S1, adding silicon source and alkali source to deionized water in sequence and stirring evenly to form solution a; S2, adding an aluminum source, ZSM-5 seed crystals, and a template agent to deionized water in sequence and stirring uniformly to form a solution b, wherein the mass ratio of the ZSM-5 seed crystals to the template agent is 1:0.5 to 5.0; S3, adding solution b dropwise to solution a, stirring and mixing until uniform, to form gel solution A; S4, dissolving the nickel salt in deionized water to obtain a nickel salt aqueous solution, adjusting the pH of the nickel salt aqueous solution to 9 to 12 with ammonia water having a mass concentration of 20% to 30% to obtain a nickel ammonia solution B having a nickel concentration of 0.1 mol / L to 4.0 mol / L; S5, adding nickel ammonia solution B to gel solution A, stirring in a sealed container at a temperature of 20° C. to 40° C. for 2 to 10 hours, and then heating at a temperature of 50° C. to 100° C. to evaporate ammonia for 1 to 6 hours to obtain a mixed gel solution C, wherein the pH value of the mixed gel solution C is 5 to 8; S6, crystallizing the mixed gel solution C at a temperature of 100° C. to 220° C. for 24 to 96 hours, filtering the obtained reaction product, washing it to neutrality, and then drying and calcining it once to obtain a catalyst precursor; S7. Immersing the obtained catalyst precursor in an ammonium salt solution for ammonium exchange, filtering and washing the impregnated catalyst precursor until the pH is 5 to 8, and then drying and secondary calcining the catalyst precursor to obtain a nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by an ammonia evaporation / in-situ synthesis method, wherein the molar ratio of the silicon source, the alkali source, the aluminum source, the template and deionized water is 30 to 290:0.4 to 28:1:5.5 to 31:2500 to 6500.

2. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by the ammonia distillation / in-situ synthesis method according to claim 1, characterized in that The silicon source is one or more of silica sol, silica gel, tetraethyl orthosilicate, sodium silicate nonahydrate and fumed silica; or / and, the alkali source is one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide; or / and, the aluminum source is one or more of aluminum sulfate, sodium metaaluminate, aluminum chloride, aluminum nitrate, aluminum isopropoxide and aluminum oxide.

3. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by the ammonia distillation / in-situ synthesis method according to claim 1 or 2, characterized in that The template agent is one or more of n-butylamine, ethylenediamine, tetrabutylammonium hydroxide and hexadecyltrimethylammonium bromide; or / and, the molar ratio of silicon to aluminum in the ZSM-5 seed crystal is 30, 150 or 300; or / and, the nickel salt is one of Ni(NO3)2·6H2O and NiSO4·6H2O.

4. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by the ammonia distillation / in-situ synthesis method according to claim 1 or 2, characterized in that In steps S6 and S7, during the first and second roasting processes, the roasting temperatures are both 530° C. to 600° C., and the roasting times are both 3 to 10 hours; or / and, in step S7, the concentration of the ammonium salt solution is 1 mol / L to 5 mol / L, the ammonium salt is one of ammonium chloride and ammonium nitrate, the ammonium exchange temperature is 30° C. to 60° C., the ammonium exchange time is 3 to 12 hours, and the number of immersions is 1 to 2 times.

5. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by the ammonia distillation / in-situ synthesis method according to claim 3, characterized in that In steps S6 and S7, during the first and second roasting processes, the roasting temperatures are both 530° C. to 600° C., and the roasting times are both 3 to 10 hours; or / and, in step S7, the concentration of the ammonium salt solution is 1 mol / L to 5 mol / L, the ammonium salt is one of ammonium chloride and ammonium nitrate, the ammonium exchange temperature is 30° C. to 60° C., the ammonium exchange time is 3 to 12 hours, and the number of immersions is 1 to 2 times.

6. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by the ammonia distillation / in-situ synthesis method according to claim 1, 2 or 5, characterized in that In steps S6 and S7, during the first and second roasting, the heating rate is controlled to be 1°C / min to 5°C / min, the drying time is 50°C to 180°C, and the drying temperature is 1h to 24h; or / and, in step S3, the stirring temperature is 10°C to 50°C, and the stirring time is 2h to 10h.

7. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by ammonia distillation / in-situ synthesis method according to claim 3, characterized in that In steps S6 and S7, during the first and second roasting, the heating rate is controlled to be 1°C / min to 5°C / min, the drying time is 50°C to 180°C, and the drying temperature is 1h to 24h; or / and, in step S3, the stirring temperature is 10°C to 50°C, and the stirring time is 2h to 10h.

8. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by ammonia distillation / in-situ synthesis method according to claim 4, characterized in that In steps S6 and S7, during the first and second roasting, the heating rate is controlled to be 1°C / min to 5°C / min, the drying time is 50°C to 180°C, and the drying temperature is 1h to 24h; or / and, in step S3, the stirring temperature is 10°C to 50°C, and the stirring time is 2h to 10h.

9. The nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by ammonia distillation / in-situ synthesis method according to claim 6, characterized in that In steps S6 and S7, during the first and second roasting, the heating rate is controlled to be 2°C / min to 3°C / min, the drying time is 90°C to 150°C, and the drying temperature is 3h to 12h; or / and, in step S3, the stirring temperature is 20°C to 30°C, and the stirring time is 2h to 5h.

10. A method for preparing a nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by the ammonia distillation / in-situ synthesis method according to any one of claims 2 to 9, characterized in that Proceed as follows: S1, adding silicon source and alkali source to deionized water in sequence and stirring evenly to form solution a; S2, adding an aluminum source, ZSM-5 seed crystals, and a template agent to deionized water in sequence and stirring uniformly to form a solution b, wherein the mass ratio of the ZSM-5 seed crystals to the template agent is 1:0.5 to 5.0; S3, adding solution b dropwise to solution a, stirring and mixing until uniform, to form gel solution A; S4, dissolving the nickel salt in deionized water to obtain a nickel salt aqueous solution, adjusting the pH of the nickel salt aqueous solution to 9 to 12 with ammonia water having a mass concentration of 20% to 30% to obtain a nickel ammonia solution B having a nickel concentration of 0.1 mol / L to 4.0 mol / L; S5, adding nickel ammonia solution B to gel solution A, stirring in a sealed container at a temperature of 20° C. to 40° C. for 2 to 10 hours, and then heating at a temperature of 50° C. to 100° C. to evaporate ammonia for 1 to 6 hours to obtain a mixed gel solution C, wherein the pH value of the mixed gel solution C is 5 to 8; S6, crystallizing the mixed gel solution C at a temperature of 100° C. to 220° C. for 24 to 96 hours, filtering the obtained reaction product, washing it to neutrality, and then drying and calcining it once to obtain a catalyst precursor; S7. Immersing the obtained catalyst precursor in an ammonium salt solution for ammonium exchange, filtering and washing the impregnated catalyst precursor until the pH is 5 to 8, and then drying and secondary calcining the catalyst precursor to obtain a nickel-based molecular sieve catalyst for methanol coupling to light hydrocarbons to olefins prepared by an ammonia evaporation / in-situ synthesis method, wherein the molar ratio of the silicon source, the alkali source, the aluminum source, the template and deionized water is 30 to 290:0.4 to 28:1:5.5 to 31:2500 to 6500.