A catalyst for improving the ethylene yield in the preparation of low-carbon olefins from methanol coupled light hydrocarbons, a preparation method and application thereof

Abstract

The application provides a catalyst for improving the ethylene yield in the preparation of low-carbon olefins from methanol and light hydrocarbons, a preparation method and application thereof, and the preparation method of the catalyst for improving the ethylene yield in the preparation of low-carbon olefins from methanol and light hydrocarbons comprises the following steps: performing alkaline hydrolysis treatment on biomass particles, and performing solid-liquid separation to obtain a biomass derivative compound solution; mixing a template agent with water, aging, and then mixing with a molecular sieve to obtain a molecular sieve precursor solution; mixing the molecular sieve precursor solution with the biomass derivative compound solution to obtain a molecular sieve precursor solution containing biomass; mixing a metal salt solution with the molecular sieve precursor solution containing biomass, granulating after reaction, and calcining to obtain the catalyst for improving the ethylene yield in the preparation of low-carbon olefins from methanol and light hydrocarbons. The catalyst can significantly improve the ethylene yield in the preparation of low-carbon olefins from methanol and light hydrocarbons.

Description

Technical Field

[0001] This invention belongs to the field of low-carbon olefin preparation technology, and relates to a catalyst for improving the ethylene yield in methanol-coupled light hydrocarbon production of low-carbon olefins, its preparation method, and its application. Background Technology

[0002] Ethylene and propylene, among other light olefins, are major petrochemical products and crucial raw materials for various organic compounds, including synthetic plastics, synthetic fibers, and rubber. Ethylene, in particular, is widely used in the plastics industry to produce polyethylene, polyvinyl chloride (PVC), and polyester, with enormous industrial consumption and high economic benefits. Currently, high-temperature steam cracking of naphtha hydrocarbons is the primary source of ethylene production. Despite significant progress in this process, its energy consumption remains the highest in the petrochemical industry. This production method typically involves heating to temperatures of 700-800°C, or even above 1000°C, resulting in complex cracking reactions that account for approximately 40% of petrochemical fuel consumption, leading to substantial carbon dioxide emissions.

[0003] Compared to energy-intensive high-temperature steam cracking processes for hydrocarbons, the methanol-hydrocarbon cracking coupled process (CMHC) combines exothermic methanol conversion with high-endothermic hydrocarbon cracking reactions on zeolites with MFI structures in a fixed-bed reactor, yielding low-carbon olefins through a thermally neutralized reaction. Residual oil, paraffin wax, and other hydrocarbons are obtained from refinery byproducts, while methanol can be obtained through gasification from sources other than petroleum, such as natural gas and coal, contributing to reduced carbon dioxide emissions. The CMHC process is an upgrade of naphtha steam cracking and methanol-to-olefins (MTO) processes.

[0004] Chinese patent application CN102531821A discloses a method for catalyzing methanol-naphtha catalytic cracking using a modified ZSM-5 molecular sieve catalyst. The catalyst used in this method is a ZSM-5 molecular sieve supported on lanthanum and phosphorus. Chinese patent application CN106607089A discloses a methanol-naphtha coupled catalytic cracking catalyst, its preparation method, and its application. The catalyst is a composite catalyst of lanthanum, phosphorus, or manganese with ZSM-5 or SAPO-34. Chinese invention patent CN111606771B discloses a methanol-light hydrocarbon coupled cracking apparatus and method, in which the catalyst used is a ZSM-5 molecular sieve. Chinese patent application CN114632544A discloses a catalyst for naphtha coupled with low-carbon alcohol ethers to produce olefins, its preparation method, and its application. The catalyst provided in this scheme is prepared from spent Fischer-Tropsch synthesis catalyst and molecular sieve. Chinese patent application CN115869863A discloses an apparatus and method for the coupled production of aromatics from naphtha and methanol, using a metal-modified HZSM-5 zeolite molecular sieve catalyst. Chinese patent application CN116410045A discloses a method and apparatus for the co-production of olefins and aromatics from light hydrocarbons coupled with methanol conversion, using one or two of ZSM-5 molecular sieves, ZSM-11 molecular sieves, and ZSM-5 / ZSM-11 eutectic molecular sieves as catalysts. Chinese patent application CN117625230A discloses a method and apparatus for the co-production of low-carbon olefins and aromatics under hypergravity reaction, using one or more of ZSM-5 molecular sieves, ZSM-11 molecular sieves, ZSM-5 / ZSM-11 eutectic molecular sieves, MCM-56 molecular sieves, and β-zeolites as catalysts.

[0005] In summary, the CMHC process currently mainly uses zeolite molecular sieves as the main catalyst, which has a large surface area, good thermal stability and abundant active sites. However, the microporous characteristics of zeolite molecular sieves cause mass transfer limitations and prevent large molecules from entering the active sites, resulting in a relatively low ethylene yield.

[0006] In conclusion, the problem of how to combine the exothermic methanol conversion with the endothermic hydrocarbon cracking reaction while significantly increasing the ethylene yield remains to be solved. Summary of the Invention

[0007] To address the problems of the prior art, this invention provides a catalyst for improving the ethylene yield in methanol-coupled light hydrocarbon-to-low-carbon olefins production, its preparation method, and its application. The catalyst for improving the ethylene yield in methanol-coupled light hydrocarbon-to-low-carbon olefins production can significantly increase the ethylene yield in methanol-coupled light hydrocarbon-to-low-carbon olefins production.

[0008] This invention is achieved through the following technical solution: A method for preparing a catalyst to improve the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin production process includes the following steps: S1, the biomass particles are subjected to alkaline hydrolysis and solid-liquid separation to obtain a biomass-derived compound solution; the template agent is mixed with water, aged, and then mixed with molecular sieves to obtain a molecular sieve precursor solution; S2, mix the molecular sieve precursor solution with the biomass-derived compound solution to obtain a molecular sieve precursor solution containing biomass; S3 involves mixing a metal salt solution with a molecular sieve precursor solution containing biomass, reacting the mixture, granulating it, and calcining it to obtain a catalyst that improves the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin production process.

[0009] Preferably, in S1, the biomass pellets are one of sugarcane bagasse, lignin, and cellulose.

[0010] Preferably, in S1, the alkaline solution used in the alkaline hydrolysis treatment is a sodium hydroxide solution.

[0011] Preferably, in S1, the molecular sieve is one or two of SAPO-34, SAPO-11, and AlPO4-5 molecular sieves.

[0012] Preferably, in S1, the mass ratio of the molecular sieve to the biomass particles is (40-80):(1-10).

[0013] Preferably, in S1, the template agent is at least one selected from tetrapropylammonium hydroxide, tetraethyl orthosilicate, aluminum isopropoxide, diisopropylamine, n-butylamine, hexadecyltrimethylammonium bromide, and cyclohexylamine.

[0014] Preferably, in S3, the metal salt in the metal salt solution is one or two of calcium nitrate, calcium sulfate, and calcium carbonate. Preferably, in step S3, the calcination temperature is 500-800℃ and the time is 3-12h.

[0015] The present invention also provides a catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons, obtained by the preparation method described above.

[0016] The present invention also provides the application of the catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons in improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons, specifically: using methanol and light hydrocarbons as raw materials, and using the catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons as described above as a catalyst, a catalytic reaction is carried out to obtain low-carbon olefins containing ethylene.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The catalyst preparation method of this invention first involves fusing a template agent with a molecular sieve to obtain a molecular sieve precursor solution. Then, the molecular sieve precursor solution is mixed with a biomass-derived compound solution. During the calcination stage, biomass acts as a hard template. Utilizing the supramolecular interactions between biomass and inorganic materials, the molecular sieve is transformed into a layered, porous zeolite molecular sieve. This effectively reduces stress concentration between pores, playing a crucial role in enhancing the catalyst's thermal stability. It also facilitates molecular adsorption and desorption, thereby minimizing pore blockage. Simultaneously, metal modification is used to regulate the catalyst's topology, acidity, and particle size, further improving the yield of ethylene in the methanol-coupled light hydrocarbon to low-carbon olefin production process. Therefore, this invention, by introducing a green and inexpensive biomass template combined with various metal modification strategies to regulate the pore structure and acidity of the molecular sieve, further improves its performance in catalysis and adsorption, thereby increasing the yield of ethylene in low-carbon olefins. Furthermore, the use of biomass can alleviate the chemical industry's dependence on non-renewable resources, helping to reduce negative environmental and production cost impacts.

[0018] The catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons, obtained by the preparation method described in this invention, is a layered porous zeolite molecular sieve. This effectively reduces stress concentration between pores, plays a crucial role in enhancing the thermal stability of the catalyst, and also facilitates molecular adsorption and desorption, thereby minimizing pore blockage.

[0019] This invention utilizes a catalyst obtained through supramolecular interactions between biomass and inorganic materials to perform a methanol-coupled light hydrocarbon to low-carbon olefin reaction. Using light hydrocarbons and methanol as raw materials, the methanol conversion reaction provides heat for the catalytic cracking of light hydrocarbons. Under the action of the catalyst, the reaction generates low-carbon olefins. The reaction conditions are mild, the raw material conversion rate is high, the yield of low-carbon olefin products is high, and the yield of ethylene in low-carbon olefins is significantly improved. Detailed Implementation

[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0021] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0022] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention. Unless otherwise specified, all raw materials and reagents used in this invention are pure reagent raw materials (concentration greater than 99%), requiring no distillation or purification treatment.

[0023] The preparation method of the catalyst for improving the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin production according to the present invention includes the following steps: (1) The biomass particles are subjected to alkaline hydrolysis and solid-liquid separation to obtain a solution of biomass-derived compounds.

[0024] Specifically, the biomass pellets described in this invention can be prepared using sugarcane bagasse, lignin, or cellulose. The specific preparation method is as follows: Untreated sugarcane bagasse, lignin, or cellulose are dried in the sun, ground, sieved, washed with water at room temperature, and dried to obtain biomass particles for the synthesis of molecular sieves.

[0025] In some specific embodiments of the present invention, a 20-80 mesh sieve is preferably used for sieving to separate particles of 20-80 mesh size as biomass pellets.

[0026] In some specific embodiments of the present invention, the drying temperature is 90-130℃ and the drying time is 2-12h.

[0027] This invention involves alkaline hydrolysis of biomass particles to fully biomineralize them, enabling the zeolite molecular sieve framework to interact with them and self-assemble into micron-sized components. Preferably, a sodium hydroxide solution is used, and the ratio of biomass particles to sodium hydroxide solution can be (1-10) g : (50-100) mL.

[0028] (2) Mix the template agent with water and age it to obtain a template agent mixed solution, and then mix it with molecular sieve to obtain a molecular sieve precursor solution.

[0029] Specifically, the template agent is mixed with water, aged, and then evaporated to obtain a template agent mixture. The template agent mixture is then mixed with molecular sieves to obtain a molecular sieve precursor solution.

[0030] The template agent described in this invention may be selected from at least one of tetrapropylammonium hydroxide, tetraethyl orthosilicate, aluminum isopropoxide, diisopropylamine, n-butylamine, hexadecyltrimethylammonium bromide, and cyclohexylamine.

[0031] The molar ratio of the template agent to water is (1-5):(20-100); the mass ratio of the template agent mixture to the molecular sieve is 1:(1-8).

[0032] As a preferred option, the stirring temperature is room temperature - 80℃, the stirring time is 0.5-6h, the aging time is 0.5-4h, and the evaporation treatment is rotary evaporation at 60-90℃ for 20-60min.

[0033] The molecular sieve described in this invention is one or two of SAPO-34, SAPO-11 and AlPO4-5 molecular sieves, and the preferred molar silica-alumina ratio of the molecular sieve is 10-50.

[0034] (3) Mix the molecular sieve precursor solution with the biomass-derived compound solution to obtain a molecular sieve precursor solution containing biomass.

[0035] In specific implementation, the molecular sieve precursor solution and the biomass-derived compound solution are stirred evenly and then sterilized under high pressure to obtain a molecular sieve precursor solution containing biomass. The molecular sieve precursor solution and the biomass-derived compound solution are mixed evenly at a mass ratio of (50-100) mL: (10-30) mL, wherein the mass ratio of molecular sieve to biomass particles is (40-80) g: (10-20) g. The stirring temperature is room temperature to 80℃, and the stirring time is 0.5-4 h.

[0036] (4) Mix the metal salt solution with the molecular sieve precursor solution containing biomass, react and then granulate to obtain the catalyst precursor.

[0037] In practice, a molecular sieve precursor solution containing biomass is added to a metal salt solution, ultrasonically treated, and stirred at a certain temperature for a certain time. Then, a spray dryer is used to convert the metal-supported catalyst into aerosol particles, which are then placed in an oven to dry to remove residual moisture, thus producing the catalyst precursor.

[0038] The metal salt in the metal salt solution may be selected from one or two of calcium nitrate, calcium sulfate, and calcium carbonate, and the mass concentration of the metal salt is 10%-15%.

[0039] In a specific embodiment, the mass ratio of the biomass-containing molecular sieve precursor solution to the metal salt solution is 1:(1-5), and the mass ratio of the metal salt to the molecular sieve, based on the content of metal elements, is (10-30)g:(40-80)g; the ultrasonic treatment temperature is room temperature to 50℃, and the ultrasonic treatment time is 0.5-4h; the stirring temperature is room temperature to 80℃, and the stirring time is 2-24h.

[0040] The spray dryer atomizer generates droplets at a speed of 15-50 revolutions per minute, and rapidly evaporates moisture at a temperature of 200-300℃ to obtain a solid metal-supported catalyst. The drying temperature is 60-150℃ and the drying time is 2-24 hours.

[0041] (5) The catalyst precursor is shaped and calcined to obtain a catalyst that improves the yield of ethylene in methanol coupled with light hydrocarbons to produce low-carbon olefins.

[0042] Specifically, the catalyst precursor and binder are mixed evenly, dried and shaped, and then calcined to obtain a catalyst for improving the ethylene yield in methanol-coupled light hydrocarbons to low-carbon olefins; wherein the calcination temperature is 400-800℃ and the calcination time is 3-12h.

[0043] The catalyst precursor forming may include the following steps: A catalyst precursor is mixed with one of the following: alumina (such as boehmite), guar gum powder, silica sol, or alumina sol. The mixture is then extruded using a dilute nitric acid solution and dried to obtain a catalyst with metal encapsulation after extrusion, which improves the yield of ethylene in the production of low-carbon olefins from methanol coupled with light hydrocarbons.

[0044] The drying temperature can be 60-200℃, the drying time can be 4-24 h, and the mass ratio of catalyst precursor to binder in the catalyst is (5-9):(1-4).

[0045] The present invention uses the catalyst prepared by the above steps to improve the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin reaction. Specifically, it includes: loading a certain amount of the catalyst to improve the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin reaction into a fixed-bed reactor; introducing methanol and light hydrocarbons into the reactor by a pump; and reacting under certain temperature, pressure and space velocity conditions; and analyzing the composition of the products by gas chromatography.

[0046] The methanol mentioned refers to a methanol solution with a purity of 99% or higher, not a mixture of methanol and water.

[0047] The light hydrocarbon may be selected from one or more of the following: hydrocracked naphtha, straight-run naphtha, hydrotreated light wax oil, reforming residue oil, and reforming topping oil.

[0048] The reaction temperature is 380-440℃, the pressure is 0-1.0MPa, and the space velocity is 1-5h. -1 .

[0049] Example 1 Sugarcane bagasse was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, the particles were dried at 120℃ for 10 hours to obtain biomass pellets. The biomass pellets were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 1 g: 50 mL, and filtered to obtain a biomass-derived compound solution. Tetrapropylammonium hydroxide (template), tetraethyl orthosilicate, and water were mixed at a molar ratio of 2:2:100, stirred at room temperature for 2 hours, aged for 2 hours, and then placed in a rotary evaporator and evaporated at 80℃ for 30 minutes. The resulting template mixture was then mixed with SAPO-34 molecular sieve (silicon-to-aluminum ratio of 50) at a mass ratio of 1:1 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 90:30 and stirred at 40℃. After mixing for 1 hour, the mixture was sterilized at 180℃ for 40 hours to obtain a molecular sieve precursor solution containing biomass. A 10.6% calcium nitrate solution was mixed uniformly with the biomass-containing molecular sieve precursor solution at a mass ratio of 3:1. The mixture was ultrasonicated at room temperature for 2 hours, then stirred in a 50℃ water bath for 24 hours. The mixture was then placed in a spray dryer, where it was rapidly converted into aerosol particles at 230℃ and a speed of 30 rpm. The particles were then dried in an oven at 120℃ for 12 hours to remove residual moisture, yielding a calcium metal-modified catalyst precursor. The calcium metal-modified catalyst precursor was mixed uniformly with the binder, pseudoboehmite, at a mass ratio of 7:3. 2% dilute nitric acid was added to form extruded strips, which were then dried in an oven at 120℃ for 4 hours and calcined in a muffle furnace at 550℃ for 6 hours to obtain a 10.6% Ca@SAPO-34 catalyst.

[0050] A 10.6% Ca@SAPO-34 strip catalyst was applied to a methanol-coupling light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:reform raffinate = 1:1 (mass ratio), and the reaction was carried out at 440℃, atmospheric pressure, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 32.4%.

[0051] Example 2 Cellulose was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, it was dried at 105℃ for 12 hours to obtain biomass pellets. The biomass pellets were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 3g:50mL, and filtered to obtain a biomass-derived compound solution. A template agent, n-butylamine, tetraethyl orthosilicate, aluminum isopropoxide, and water were mixed at a molar ratio of 1:1:1:100, stirred at 35℃ for 2.5 hours, aged for 3 hours, and then placed in a rotary evaporator and evaporated at 90℃ for 20 minutes. The resulting template agent mixture was then mixed with SAPO-11 molecular sieve with a silica-to-alumina ratio of 50 at a mass ratio of 1:1 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 70:30. The mixture was stirred at room temperature for 2 hours and then sterilized at 180°C for 40 hours to obtain a molecular sieve precursor solution containing biomass. An 11.2% calcium sulfate solution was mixed with the biomass-containing molecular sieve precursor solution at a mass ratio of 3:1. The mixture was ultrasonicated at 35°C for 2 hours and then stirred at room temperature for 24 hours. The mixture was then placed in a spray dryer, where it was rapidly converted into aerosol particles at 200°C and a speed of 40 rpm. The particles were then dried in an oven at 150°C for 8 hours to remove residual moisture, yielding a metal-modified catalyst precursor. The metal-modified catalyst precursor was mixed with the binder guar gum powder at a mass ratio of 7:3. 2% dilute nitric acid was added to form extruded strips, which were then dried in an oven at 120°C for 6 hours and calcined in a muffle furnace at 550°C for 6 hours to obtain an 11.2% Ca@SAPO-11 catalyst.

[0052] An 11.2% Ca@SAPO-11 strip catalyst was applied to the methanol-coupled light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:hydrocracked naphtha = 1:1 (mass ratio), and the reaction was carried out at 390℃, atmospheric pressure, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 37.5%.

[0053] Example 3 Sugarcane bagasse was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, the particles were dried at 125℃ for 8 hours to obtain biomass pellets. The biomass pellets were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 2g:90mL, and filtered to obtain a biomass-derived compound solution. The template agent, hexadecyltrimethylammonium bromide, was mixed with water at a molar ratio of 5:80, stirred at 55℃ for 1.5 hours, aged for 0.5 hours, and then placed in a rotary evaporator and evaporated at 70℃ for 50 minutes. The resulting template agent mixture was then mixed with SAPO-34 molecular sieve with a silica-to-alumina ratio of 40 at a mass ratio of 1:3 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 50:10 at 55℃. After stirring for 1 hour, the mixture was sterilized at 180℃ for 40 hours to obtain a molecular sieve precursor solution containing biomass. A 10% calcium sulfate solution was mixed uniformly with the biomass-containing molecular sieve precursor solution at a mass ratio of 3:1. The mixture was ultrasonicated at room temperature for 2.5 hours, then stirred at 40℃ for 15 hours. The mixture was then placed in a spray dryer, where it was rapidly converted into aerosol particles at 180℃ and a speed of 50 rpm. The particles were then dried in an oven at 100℃ for 15 hours to remove residual moisture, yielding a calcium metal-modified catalyst precursor. This calcium metal-modified catalyst precursor was mixed uniformly with a binder aluminum sol at a mass ratio of 5:2. 2% dilute nitric acid was added to form extruded strips, which were then dried in an oven at 150℃ for 4 hours and calcined in a muffle furnace at 530℃ for 6 hours to obtain a 10% Ca@SPAO-34 catalyst.

[0054] A 10% Ca@SPAO-34 strip catalyst was applied to a methanol-coupling light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:reform raffinate = 3:1 (mass ratio), and the reaction was carried out at 420℃, 0.3 MPa, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 29.8%.

[0055] Example 4 Lignin was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, it was dried at 90℃ for 12 hours to obtain biomass particles. The biomass particles were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 2 g: 60 mL, and filtered to obtain a biomass-derived compound solution. The template agent hexadecyltrimethylammonium bromide, cyclohexylamine, and water were mixed at a molar ratio of 2:3:80, stirred at 70℃ for 1 hour, aged for 2 hours, and then placed in a rotary evaporator and rotary evaporated at 90℃ for 30 minutes. The resulting template agent mixture was mixed with AlPO4-5 molecular sieves with a silica-alumina ratio of 30 at a mass ratio of 1:6 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 80:20. After stirring at room temperature for 4 hours, the mixture was sterilized at 180℃ for 40 hours to obtain a molecular sieve precursor solution containing biomass. A 15% calcium nitrate solution was mixed uniformly with the biomass-containing molecular sieve precursor solution at a mass ratio of 5:1. The mixture was ultrasonicated at room temperature for 4 hours, then stirred at room temperature for 20 hours. The mixture was then placed in a spray dryer, where it was rapidly converted into aerosol particles at 260℃ and a speed of 30 rpm. The particles were then dried in an oven at 120℃ for 8 hours to remove residual moisture, yielding a metal-modified catalyst precursor. The metal-modified catalyst precursor was mixed uniformly with the binder pseudoboehmite at a mass ratio of 6:4. 2% dilute nitric acid was added to form extruded strips, which were then dried in an oven at 110℃ for 3 hours and calcined in a muffle furnace at 600℃ for 4 hours to obtain a 15% Ca@AlPO4-5 catalyst.

[0056] A 15% Ca@AlPO4-5 strip catalyst was applied to the methanol-coupling light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:hydrogenated light wax oil = 2:1 (mass ratio), and the reaction was carried out at 400℃, 0.1 MPa, and a space velocity of 2 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 38.7%.

[0057] Example 5 Cellulose was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, it was dried at 130℃ for 10 hours to obtain biomass pellets. The biomass pellets were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 1.5 g: 60 mL, and filtered to obtain a biomass-derived compound solution. Tetraethyl orthosilicate, a template agent, was mixed with water at a molar ratio of 2:30, stirred at 60℃ for 3 hours, aged for 4 hours, and then placed in a rotary evaporator and rotary evaporated at 80℃ for 45 minutes. The resulting template agent mixture was then mixed with SAPO-34 (silicon-to-aluminum ratio of 15) and SAPO-11 (silicon-to-aluminum ratio of 10) molecular sieves (SAPO-34 to SAPO-11 mass ratio of 6:4) at a mass ratio of 1:6 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution according to... A molecular sieve precursor solution containing biomass was obtained by stirring at 66℃ for 2 hours and then sterilizing at 180℃ for 40 hours at a mass ratio of 70:6. A 14.2% calcium nitrate solution was then uniformly mixed with the biomass-containing molecular sieve precursor solution at a mass ratio of 2:1, sonicated at 40℃ for 4 hours, and stirred at room temperature for 22 hours. The mixture was then placed in a spray dryer and rapidly converted into aerosol particles at 240℃ and a speed of 20 rpm. The particles were then dried in an oven at 130℃ for 12 hours to remove residual moisture, yielding a metal-modified catalyst precursor. The metal-modified catalyst precursor was then uniformly mixed with a binder silica sol at a mass ratio of 5:2, and 2% dilute nitric acid was added to form extruded strips. The strips were then dried in an oven at 80℃ for 6 hours and calcined in a muffle furnace at 600℃ for 6 hours to obtain a 14.2% Ca@SAPO-34-SAPO-11 catalyst.

[0058] A 14.2% Ca@SAPO-34-SAPO-11 strip catalyst was applied to a methanol-coupled light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:DC naphtha = 1:2 (mass ratio), and the reaction was carried out at 420℃, 0.2 MPa, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 39.5%.

[0059] Example 6 Sugarcane bagasse was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, the particles were dried at 90℃ for 15 hours to obtain biomass pellets. The biomass pellets were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 8g:80mL, and filtered to obtain a biomass-derived compound solution. Cyclohexylamine, diisopropylamine, and water were mixed at a molar ratio of 2:3:100, stirred at 55℃ for 1.5 hours, aged for 2.5 hours, and then placed in a rotary evaporator and evaporated at 75℃ for 35 minutes. The resulting template agent mixture was then mixed with AlPO4-5-SPAO-34 molecular sieve (AlPO4-5 to SPAO-34 mass ratio of 7:3) at a mass ratio of 1:6 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 100... A molecular sieve precursor solution containing biomass was obtained by stirring at 61℃ for 1.5h and then sterilizing at 180℃ for 40h at a mass ratio of 1:1 with a 13.5% calcium nitrate solution. The mixture was then sonicated at 35℃ for 2.5h and stirred at 65℃ for 10h. The mixture was then placed in a spray dryer and rapidly converted into aerosol particles at 230℃ and a speed of 35 rpm. The particles were then dried in an oven at 80℃ for 18h to remove residual moisture, resulting in a metal-modified catalyst precursor. The metal-modified catalyst precursor was then mixed with guar gum powder as a binder at a mass ratio of 5:2. After adding 2% dilute nitric acid, the mixture was extruded and dried in an oven at 120℃ for 4h. Finally, it was calcined in a muffle furnace at 500℃ for 6h to obtain a 13.5% Ca@AlPO4-5-SPAO-34 catalyst.

[0060] A 13.5% Ca@AlPO4-5-SPAO-34 strip catalyst was applied to the methanol-coupled light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:DC naphtha = 1:2 (mass ratio), and the reaction was carried out at 440℃, atmospheric pressure, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 31.2%.

[0061] Example 7 Lignin was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, it was dried at 108℃ for 10 hours to obtain biomass particles. The biomass particles were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 5g:70mL, and filtered to obtain a biomass-derived compound solution. Tetrapropylammonium hydroxide, a template agent, was mixed with water at a molar ratio of 3:50, stirred at 42℃ for 1 hour, aged for 1 hour, and then placed in a rotary evaporator and rotary evaporated at 60℃ for 55 minutes. The resulting template agent mixture was mixed with SAPO-34 molecular sieve with a silica-alumina ratio of 15 at a mass ratio of 1:2 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 90:30 and stirred at 37℃. After 3 hours, the mixture was sterilized at 180℃ for 40 hours to obtain a molecular sieve precursor solution containing biomass. A 12.1% calcium carbonate solution was mixed uniformly with the biomass-containing molecular sieve precursor solution at a mass ratio of 2:1. The mixture was ultrasonicated at 40℃ for 3 hours, then stirred at 30℃ for 20 hours. The mixture was then placed in a spray dryer, where it was rapidly converted into aerosol particles at 230℃ and a speed of 40 rpm. The particles were then dried in an oven at 150℃ for 4 hours to remove residual moisture, yielding a metal-modified catalyst precursor. The metal-modified catalyst precursor was mixed uniformly with the binder, pseudoboehmite, at a mass ratio of 6:2. 2% dilute nitric acid was added to form extruded strips, which were then dried in an oven at 100℃ for 6 hours and calcined in a muffle furnace at 520℃ for 5 hours to obtain a 12.1% Ca@SAPO-34 catalyst.

[0062] A 12.1% Ca@SAPO-34 strip catalyst was applied to a methanol-coupling light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:reform raffinate = 1:1 (mass ratio), and the reaction was carried out at 430℃, atmospheric pressure, and a space velocity of 2 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 38.5%.

[0063] Example 8 Cellulose was sun-dried, ground, and sieved to obtain 20-80 mesh particles. After washing with water at room temperature, it was dried at 116℃ for 8 hours to obtain biomass pellets. The biomass pellets were then subjected to alkaline hydrolysis with sodium hydroxide solution at a ratio of 6g:80mL, and filtered to obtain a biomass-derived compound solution. The template agent n-butylamine was mixed at a ratio of 4:80, stirred at 60℃ for 2.5 hours, aged for 2.5 hours, and then placed in a rotary evaporator and rotary evaporated at 68℃ for 35 minutes. The resulting template agent mixture was mixed with SAPO-11 molecular sieve with a silica-to-alumina ratio of 50 at a mass ratio of 1:1 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with the biomass-derived compound solution at a mass ratio of 60:20 and stirred at 45℃ for 2 hours. After sterilization at 180℃ for 40 hours, a molecular sieve precursor solution containing biomass was obtained. A 10% calcium sulfate solution was mixed uniformly with the biomass-containing molecular sieve precursor solution at a mass ratio of 3:1. The mixture was ultrasonicated at 35℃ for 2 hours, stirred at room temperature for 13 hours, and then placed in a spray dryer. The atomizer was used to rapidly convert the mixture into aerosol particles at 200℃ and a speed of 30 rpm. The particles were then dried in an oven at 130℃ for 7 hours to remove residual moisture, yielding a metal-modified catalyst precursor. The metal-modified catalyst precursor was mixed uniformly with the binder guar gum powder at a mass ratio of 7:3. 2% dilute nitric acid was added to form extruded strips, which were then dried in an oven at 120℃ for 6 hours and calcined in a muffle furnace at 800℃ for 12 hours to obtain a 10% Ca@SAPO-11 catalyst.

[0064] A 10% Ca@SAPO-11 strip catalyst was applied to the methanol-coupled light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:hydrocracked naphtha = 1:1 (mass ratio), and the reaction was carried out at 400℃, atmospheric pressure, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 100% and the ethylene yield was 30.4%.

[0065] Comparative Example 1 Except for the uniform mixing of 10.6% copper sulfate solution and biomass-containing molecular sieve precursor solution at a ratio of 3:1, the catalytic reaction was carried out using the same catalyst preparation method and methanol-coupled light hydrocarbon process conditions as in Example 1. Analysis of the products revealed a methanol conversion rate of 88%, with an ethylene yield of 5.5%.

[0066] Comparative Example 2 Except for the experimental method involving the addition of biomass, the reaction was carried out using the same catalyst preparation method and methanol-coupled light hydrocarbon process conditions as in Example 3: The template agent, hexadecyltrimethylammonium bromide, was mixed with water at a molar ratio of 5:80, stirred at 55°C for 1.5 h, and aged for 0.5 h. The mixture was then placed in a rotary evaporator and evaporated at 70°C for 50 min. The resulting template agent mixture was then mixed with SAPO-34 molecular sieve (silicon-to-aluminum ratio 40) at a mass ratio of 1:3 to obtain a molecular sieve precursor solution. The molecular sieve precursor solution was then mixed with a biomass-derived compound solution at a mass ratio of 50:10, stirred at 55°C for 1 h, and then sterilized at 180°C for 40 h to obtain a biomass-containing molecular sieve precursor solution. A 10% calcium sulfate solution was then mixed with the biomass-containing molecular sieve precursor solution. The precursor solution was uniformly mixed at a mass ratio of 3:1, sonicated at room temperature for 2.5 h, stirred at 40 °C for 15 h, and then placed in a spray dryer. The atomizer was used to rapidly convert the precursor into aerosol particles at a speed of 50 rpm and a temperature of 180 °C. The atomizer was then dried in an oven at 100 °C for 15 h to remove residual moisture, yielding a calcium metal modified catalyst precursor. The calcium metal modified catalyst precursor was mixed uniformly with the binder aluminum sol at a mass ratio of 5:2, and 2% dilute nitric acid was added to form extruded strips. The strips were then dried in an oven at 150 °C for 4 h and calcined in a muffle furnace at 530 °C for 6 h to obtain a 10% Ca@SPAO-34 catalyst.

[0067] A 10% Ca@SPAO-34 strip catalyst was applied to a methanol-coupling light hydrocarbon to low-carbon olefin reaction in a fixed-bed reactor. The feedstock was methanol:reform raffinate = 3:1 (mass ratio), and the reaction was carried out at 420℃, 0.3 MPa, and a space velocity of 1 h⁻¹. -1 The reaction was carried out over time, and the product analysis showed that the methanol conversion rate was 75%, of which the ethylene yield was 5.4%.

[0068] Comparative Example 3 The portion using the spray dryer-supported catalyst was removed, and the unsupported SPAO-34 catalyst was used directly. The remaining portion was the same as in Example 3. Analysis of the product showed that the methanol conversion rate was 72%, and the ethylene yield was 4.6%.

[0069] Comparative Example 4 Using the same catalyst as in Example 4, the reaction of methanol to low-carbon olefins was carried out. Except for the reaction raw materials, which were different from those in Example 4, namely, methanol was used as the raw material, the reaction process conditions were completely the same. The analysis of the products showed that the methanol conversion rate was 83%, and the ethylene yield was 6.8%.

[0070] Comparative Example 5 Using the same catalyst as in Example 4, the reaction of light hydrocarbons to low-carbon olefins was carried out. Except for the reaction raw materials, which were different from those in Example 4, namely, using light hydrocarbons alone as raw materials, the reaction process conditions were completely the same. The analysis of the products showed that the ethylene yield was 3.2%.

[0071] Comparing Comparative Example 1 with Example 1, it can be seen that changing the metal element significantly alters the ethylene yield compared to using a 6% copper sulfate solution, indicating that metal modification also has a regulatory effect on the internal structure of the catalyst.

[0072] Comparing Comparative Example 2 with Example 3, it can be seen that the catalyst with added biomass significantly improves the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin reaction compared to the catalyst without biomass. This is because the addition of biomass promotes the formation of stratified zeolite molecular sieves, effectively reduces stress concentration between pores, and plays a crucial role in enhancing the thermal stability of the catalyst. It also facilitates molecular adsorption and desorption, thereby minimizing pore blockage.

[0073] Compared with Comparative Examples 4 and 5, and Example 4, combining the exothermic methanol conversion with the endothermic hydrocarbon cracking reaction can promote the occurrence of the reaction, indicating that the active sites of the catalyst are suitable for the methanol-coupled light hydrocarbon to olefin reaction system, and the resulting coupling modification effect favorably promotes the occurrence of the catalytic reaction.

Claims

1. A method for preparing a catalyst to improve the ethylene yield in the methanol-coupled light hydrocarbon to low-carbon olefin production process, characterized in that, Includes the following steps: The biomass pellets were subjected to alkaline hydrolysis and solid-liquid separation to obtain a solution of biomass-derived compounds. The template agent is mixed with water, aged, and then mixed with molecular sieve to obtain a molecular sieve precursor solution; The molecular sieve precursor solution is mixed with the biomass-derived compound solution to obtain a molecular sieve precursor solution containing biomass. A metal salt solution was mixed with a molecular sieve precursor solution containing biomass, and after reaction, the mixture was granulated and calcined to obtain a catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons.

2. The method for preparing the catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons according to claim 1, characterized in that, The biomass pellets are one of sugarcane bagasse, lignin, and cellulose.

3. The method for preparing the catalyst for improving the ethylene yield in methanol-coupled light hydrocarbons to low-carbon olefins according to claim 1, characterized in that, The alkaline solution used in the alkaline hydrolysis treatment is a sodium hydroxide solution.

4. The method for preparing the catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons according to claim 1, characterized in that, The molecular sieve is one or two of SAPO-34, SAPO-11 and AlPO4-5 molecular sieves.

5. The method for preparing the catalyst for improving the ethylene yield in methanol-coupled light hydrocarbons to low-carbon olefins according to claim 1, characterized in that, The mass ratio of the molecular sieve to the biomass pellets is (40-80):(1-10).

6. The method for preparing the catalyst for improving the ethylene yield in methanol-coupled light hydrocarbons to low-carbon olefins according to claim 1, characterized in that, The template agent is at least one selected from tetrapropylammonium hydroxide, tetraethyl orthosilicate, aluminum isopropoxide, diisopropylamine, n-butylamine, hexadecyltrimethylammonium bromide, and cyclohexylamine.

7. The method for preparing the catalyst for improving the ethylene yield in methanol-coupled light hydrocarbons to low-carbon olefins according to claim 1, characterized in that, The metal salt in the metal salt solution is one or two of calcium nitrate, calcium sulfate, and calcium carbonate.

8. The method for preparing the catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons according to claim 1, characterized in that, The roasting temperature is 500-800℃, and the time is 3-12h.

9. A catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons, obtained by the preparation method according to any one of claims 1-8.

10. The application of the catalyst for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons according to claim 9 in improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons, characterized in that, Using methanol and light hydrocarbons as raw materials, and the catalyst described in claim 9 for improving the ethylene yield in the production of low-carbon olefins from methanol coupled with light hydrocarbons as a catalyst, a catalytic reaction is carried out to obtain low-carbon olefins containing ethylene.