A process and apparatus for the production of aromatics from methanol

Abstract

This invention discloses a method and apparatus for preparing aromatics from methanol. The method includes: sequentially performing a hydrocarbonation reaction and an aromatization reaction on methanol under the action of a hydrocarbonation catalyst to obtain an aromatization product; performing preliminary separation on the aromatization product to obtain a light component, mixed aromatics, and water, with the light component returned to the aromatization reaction step; separating the mixed aromatics to obtain light aromatics and heavy aromatics; and performing a cracking reaction on the heavy aromatics under the action of a cracking catalyst, with the cracking product returned to the preliminary separation step. The process flow, catalyst selection, and three-stage reaction conditions of this application for preparing aromatics from methanol achieve gradient separation and directional conversion of the reaction products, effectively suppressing side reactions and improving the purity and yield of the target product.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and more specifically, to a method and apparatus for preparing aromatics from methanol. Background Technology

[0002] Aromatics, as a key component of the basic organic chemical raw material system, especially light aromatics (BTX, benzene, toluene, and xylene), rank third globally in terms of industrial scale, second only to ethylene and propylene. These basic chemicals are core raw materials for the chemical fiber industry, engineering plastics manufacturing, and the synthesis of high-performance materials, playing an irreplaceable role in the three major synthetic materials fields of synthetic resins, synthetic fibers, and synthetic rubber. They are also important precursors for pharmaceutical preparations, dye chemicals, and pesticide production. Given the current increasingly strained global oil resources, developing new aromatic preparation technologies based on non-petroleum routes to diversify raw material sources has become a research and development direction of significant strategic importance.

[0003] Recent technological advancements have given coal-based methanol production significant advantages: the successful development of efficient, long-cycle methanol catalysts and the mature application of large-scale plant technology have significantly reduced production costs. Industry data shows that in 2024, global methanol production capacity reached 177 million tons, while actual consumption was 139 million tons; it is predicted that global capacity will further increase to 189 million tons in 2025, leading to a relative oversupply in the market. This production capacity structure provides a highly cost-effective raw material guarantee for downstream methanol products (including olefins and aromatics). Moreover, while methanol-to-olefins technology is fully mature, effective routes for methanol-to-aromatics production, as well as the development of industrial-scale routes, have not yet been established domestically or internationally. Therefore, the development of methanol-based light aromatics production technology is of great strategic significance.

[0004] A significant characteristic of the methanol-to-aromatics (MTO) process lies in its complex product distribution: in addition to the target aromatics, C2-C3 low-carbon hydrocarbons and a large amount of hydrogen are also generated. To improve the aromatics yield, the low-carbon hydrocarbons need to undergo aromatization conversion and recovery. However, this technology still faces several key challenges: First, all reactions must be coupled within a single reactor under constant temperature conditions, leading to complex interrelationships between the reaction systems; second, the severe backmixing phenomenon prevalent in the dense phase region of the fluidized bed not only weakens the driving force of the aromatization reaction but also promotes the hydrogen transfer reaction, resulting in an increase in alkane byproducts. These factors collectively lead to technical bottlenecks in the current MTO technology, such as low BTX selectivity and excessively high energy consumption for product separation, severely restricting the industrial-scale promotion of this process. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for preparing aromatics from methanol, which is beneficial to improving the selectivity of aromatics and the yield of BTX.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a method for preparing aromatics from methanol, comprising: The alkylation reaction involves alkylating methanol with a catalyst to obtain the alkylation product. Aromatization reaction: The hydrocarbon product is subjected to an aromatization reaction in the presence of an aromatization catalyst to obtain the aromatized product. Preliminary separation: The aromatized products are preliminarily separated to obtain a light component, mixed aromatics and water. The light component is returned to the aromatization reaction step. The mixed aromatics are separated to obtain light aromatics and heavy aromatics; The cracking reaction involves cracking heavy aromatics in the presence of a cracking catalyst, and the resulting cracking products are returned to the preliminary separation step.

[0007] In an optional embodiment, the reactor used for the hydrocarbonation reaction is selected from one of a fixed-bed reactor, a moving-bed reactor, and a fluidized-bed reactor; And / or, the hydrocarbonation reaction catalyst includes a first active metal and a first molecular sieve support loaded with the first active metal, wherein the first molecular sieve support is selected from at least one of SAPO-34 molecular sieve, SAPO-18 molecular sieve and ZSM-5 molecular sieve, and the first active metal is selected from at least one of Ni, Mo and Zn; In an optional embodiment, the hydrocarbonation reaction is carried out at a temperature of 400–550°C, a pressure of 0.01–2.0 MPa, and a mass hourly space velocity of 0.1–8 h⁻¹. -1 ; And / or, the olefin yield in the alkylation reaction is not less than 80 wt%.

[0008] In an optional embodiment, the reactor used for the aromatization reaction is a fixed-bed reactor; And / or, the aromatization reaction catalyst includes a second active metal and a second molecular sieve support on which the second active metal is supported, wherein the second molecular sieve support is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve and ZSM-12 molecular sieve, and the second active metal is selected from at least one of Zr, Zn, Cs and Mo.

[0009] In an optional embodiment, the aromatization reaction is carried out at a temperature of 160–350 °C, a pressure of 0.1–2.0 MPa, and a mass hourly space velocity of 0.1–8 h⁻¹. -1 .

[0010] In an optional embodiment, the reactor used for the pyrolysis reaction is a fluidized bed reactor; And / or, the cracking reaction catalyst comprises a hydrogenation active metal and a third molecular sieve support on which the hydrogenation active metal is supported, wherein the third molecular sieve support is selected from at least one of mordenite, ZSM-5 molecular sieve and β-zeolite, and the hydrogenation active metal is selected from at least one of Zn, Fe, Ni, Pt, Cu and Co.

[0011] In an optional embodiment, the pyrolysis reaction temperature is 500~700℃, the pressure is 0.1~2.0 MPa, and the mass hourly space velocity is 0.1~8 h⁻¹. -1 .

[0012] In an optional embodiment, in the method for preparing aromatics from methanol, the methanol conversion rate is above 99.5 wt%, the aromatic yield is not less than 85 wt%, and the BTX yield is not less than 70 wt%.

[0013] In an optional embodiment, the hydrocarbonation reaction catalyst includes a first active metal and a first molecular sieve support loaded with the first active metal, wherein the first molecular sieve support is selected from at least one of SAPO-34 molecular sieve and ZSM-5 molecular sieve, and the first active metal is selected from at least one of Ni and Zn. And / or, the aromatization reaction catalyst comprises a second active metal and a second molecular sieve support loaded with the second active metal, wherein the second molecular sieve support is selected from ZSM-5 molecular sieve, and the second active metal is selected from at least one of Zr and Zn; And / or, the cracking reaction catalyst comprises a hydrogenation active metal and a third molecular sieve support on which the hydrogenation active metal is supported, wherein the third molecular sieve support is selected from ZSM-5 molecular sieve, and the hydrogenation active metal is selected from at least one of Zn, Fe, Ni, Pt, Cu and Co.

[0014] Secondly, the present invention provides an apparatus for the method of preparing aromatics from methanol according to any one of the foregoing embodiments, comprising: A hydrocarbonation reactor is used to carry out the hydrocarbonation reaction. The hydrocarbonation reactor has a methanol inlet at the bottom and a hydrocarbonation product outlet at the top. An aromatization reactor is used to carry out the aromatization reaction. The top of the aromatization reactor is provided with a light component outlet and a hydrocarbon product inlet connected to the hydrocarbon product outlet, and the bottom is provided with an aromatization product outlet. A preliminary separator is provided for the preliminary separation. The preliminary separator has an aromatization product inlet connected to the aromatization product outlet at the bottom, a drain outlet at the bottom, a pyrolysis product inlet at the top, and a light component outlet connected to the light component inlet. A secondary separator is used to perform the separation. The secondary separator has a mixed aromatics inlet at the top, a light aromatics outlet at the bottom, and a heavy aromatics outlet at the bottom. A pyrolysis reactor is used to carry out the pyrolysis reaction. The bottom of the pyrolysis reactor is provided with a heavy aromatics inlet connected to the heavy aromatics outlet, and the top is provided with a pyrolysis product outlet connected to the pyrolysis product inlet.

[0015] The present invention has the following beneficial effects: This application discloses a three-stage reaction-two-stage separation method for preparing aromatics from methanol. The process, along with the selection of catalysts and the matching of reaction conditions for the three-stage reaction, successfully solves the key technical bottlenecks in the methanol-to-aromatics process, such as complex reaction pathways, diverse intermediate products, numerous by-reaction products, high energy consumption, and low BTX yield. It realizes the gradient separation and directional conversion of reaction products, effectively suppresses the occurrence of side reactions, and improves the purity and yield of the target product. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the equipment for preparing aromatics from methanol.

[0018] Diagram: 1- Hydrocarbonization reactor; 2- Aromatization reactor; 3- Cracking reactor; 4- Primary separator; 5- Secondary separator. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] The SAPO-34 molecular sieve, SAPO-18 molecular sieve, ZSM-5 molecular sieve, ZSM-11 molecular sieve and ZSM-12 molecular sieve in the examples are all from Sichuan Aolifen Catalytic Materials Co., Ltd.

[0021] The mordenite used in the examples was sourced from Sichuan Aolifen Catalytic Materials Co., Ltd.

[0022] The β-zeolite molecular sieve used in the examples was sourced from Sichuan Aolifen Catalytic Materials Co., Ltd.

[0023] This invention provides a method for preparing aromatics from methanol, comprising: The alkylation reaction involves alkylating methanol with a catalyst to obtain the alkylation product. Aromatization reaction: The hydrocarbon product is subjected to an aromatization reaction in the presence of an aromatization catalyst to obtain the aromatized product. Preliminary separation: The aromatized products are preliminarily separated to obtain a light component, mixed aromatics and water. The light component is returned to the aromatization reaction step. The mixed aromatics are separated to obtain light aromatics and heavy aromatics; The cracking reaction involves cracking heavy aromatics in the presence of a cracking catalyst, and the resulting cracking products are returned to the preliminary separation step.

[0024] This application discloses a three-stage reaction-two-stage separation method for preparing aromatics from methanol. The process, along with the selection of catalysts and the reaction conditions of the three-stage reaction, successfully solves the key technical bottlenecks in the methanol-to-aromatics process, such as complex reaction paths, diverse intermediate products, numerous by-reaction products, high energy consumption, and low BTX yield. It achieves gradient separation and directional conversion of reaction products, effectively suppresses the occurrence of side reactions, and improves the purity and yield of the target product.

[0025] In the method for preparing aromatics from methanol in this application, methanol produces olefins and water under the action of a hydrocarbonation catalyst. The olefins and water are transferred to aromatization reactor 2, where they are further reacted with the aromatization catalyst to produce mixed aromatics (BTX and C9+ aromatics) and a small amount of unreacted light olefin components. The mixed products enter a primary separation unit for preliminary separation. In this unit, the differences in boiling point and density of the components are utilized: the densest water settles to the bottom and is discharged; the intermediate oil phase (mixed aromatics) is extracted and sent to the next separation unit; the light olefin gas with the lowest boiling point and lowest density escapes from the top, is collected, pressurized, and recycled back to aromatization reactor 2 for further reaction. The mixed aromatics from the primary separation enter the separation step to separate the target product BTX; the C9+ aromatics undergo a cracking reaction under the action of a cracking catalyst, and the products undergo primary separation again. This cycle greatly improves the yield of aromatics and BTX.

[0026] In optional embodiments, the reactor used for the hydrocarbonation reaction is selected from one of a fixed-bed reactor, a moving-bed reactor, and a fluidized-bed reactor. These three different types of reactors have distinct structural designs, but all can effectively achieve the goal of efficiently catalytically converting methanol into aromatics. Fixed-bed reactors offer advantages such as simple structure and convenient operation; moving-bed reactors enable continuous catalyst regeneration, improving reaction efficiency; and fluidized-bed reactors feature excellent mass and heat transfer performance. Regardless of the reactor type used, by optimizing reaction conditions and the catalyst system, a significant improvement in methanol conversion rate and aromatics selectivity can be ensured, ultimately achieving the process goal of efficiently converting methanol into aromatics.

[0027] And / or, the hydrocarbonation reaction catalyst includes a first active metal and a first molecular sieve support loaded with the first active metal, wherein the first molecular sieve support is selected from at least one of SAPO-34 molecular sieve, SAPO-18 molecular sieve and ZSM-5 molecular sieve, and the first active metal is selected from at least one of Ni, Mo and Zn; In an optional embodiment, the hydrocarbonation reaction is carried out at a temperature of 400–550°C, a pressure of 0.01–2.0 MPa, and a mass hourly space velocity of 0.1–8 h⁻¹. -1 ; And / or, the olefin yield in the alkylation reaction is not less than 80 wt%.

[0028] In an optional embodiment, the reactor used for the aromatization reaction is a fixed-bed reactor; And / or, the aromatization reaction catalyst includes a second active metal and a second molecular sieve support on which the second active metal is supported, wherein the second molecular sieve support is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve and ZSM-12 molecular sieve, and the second active metal is selected from at least one of Zr, Zn, Cs and Mo.

[0029] In an optional embodiment, the aromatization reaction is carried out at a temperature of 160–350 °C, a pressure of 0.1–2.0 MPa, and a mass hourly space velocity of 0.1–8 h⁻¹. -1 .

[0030] In an optional embodiment, the reactor used for the pyrolysis reaction is a fluidized bed reactor; And / or, the cracking reaction catalyst comprises a hydrogenation active metal and a third molecular sieve support on which the hydrogenation active metal is supported, wherein the third molecular sieve support is selected from at least one of mordenite, ZSM-5 molecular sieve and β-zeolite, and the hydrogenation active metal is selected from at least one of Zn, Fe, Ni, Pt, Cu and Co.

[0031] In an optional embodiment, the pyrolysis reaction temperature is 500~700℃, the pressure is 0.1~2.0 MPa, and the mass hourly space velocity is 0.1~8 h⁻¹. -1 .

[0032] In an optional embodiment, in the method for preparing aromatics from methanol, the methanol conversion rate is above 99.5 wt%, the aromatic yield is not less than 85 wt%, and the BTX yield is not less than 70 wt%.

[0033] In an optional embodiment, the hydrocarbonation reaction catalyst includes a first active metal and a first molecular sieve support loaded with the first active metal, wherein the first molecular sieve support is selected from at least one of SAPO-34 molecular sieve and ZSM-5 molecular sieve, and the first active metal is selected from at least one of Ni and Zn. And / or, the aromatization reaction catalyst comprises a second active metal and a second molecular sieve support loaded with the second active metal, wherein the second molecular sieve support is selected from ZSM-5 molecular sieve, and the second active metal is selected from at least one of Zr and Zn; And / or, the cracking reaction catalyst comprises a hydrogenation active metal and a third molecular sieve support on which the hydrogenation active metal is supported, wherein the third molecular sieve support is selected from ZSM-5 molecular sieve, and the hydrogenation active metal is selected from at least one of Zn, Fe, Ni, Pt, Cu and Co.

[0034] The present invention also provides an apparatus for the method of preparing aromatics from methanol as described in any of the foregoing embodiments, such as... Figure 1 As shown, it includes: Hydrocarbonization reactor 1 is used to carry out the hydrocarbonization reaction. The bottom of the hydrocarbonization reactor 1 is provided with a methanol inlet and the top is provided with a hydrocarbonization product outlet. The aromatization reactor 2 is used to carry out the aromatization reaction. The top of the aromatization reactor 2 is provided with a light component outlet and a hydrocarbon product inlet connected to the hydrocarbon product outlet, and the bottom is provided with an aromatization product outlet. A preliminary separator 4 is used for the preliminary separation. The preliminary separator 4 has an aromatization product inlet connected to the aromatization product outlet at the bottom, a drain outlet at the bottom, a pyrolysis product inlet at the top, and a light component outlet connected to the light component inlet; specifically, it can be a three-phase separator. A secondary separator 5 is used to perform the separation. The secondary separator 5 is provided with a mixed aromatic hydrocarbon inlet at the top and a light aromatic hydrocarbon outlet at the bottom. The secondary separator 5 is also provided with a heavy aromatic hydrocarbon outlet at the bottom. Specifically, it can be a distillation column. The cracking reactor 3 is used to carry out the cracking reaction. The bottom of the cracking reactor 3 is provided with a heavy aromatics inlet connected to the heavy aromatics outlet, and the top is provided with a cracking product outlet connected to the cracking product inlet.

[0035] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0036] Example 1: This embodiment provides an apparatus for preparing aromatics from methanol, such as... Figure 1 As shown, it includes: Hydrocarbonization reactor 1 is used to carry out the hydrocarbonization reaction. The bottom of the hydrocarbonization reactor 1 is provided with a methanol inlet and the top is provided with a hydrocarbonization product outlet. The aromatization reactor 2 is used to carry out the aromatization reaction. The top of the aromatization reactor 2 is provided with a light component outlet and a hydrocarbon product inlet connected to the hydrocarbon product outlet, and the bottom is provided with an aromatization product outlet. A preliminary separator 4 is used for the preliminary separation. The preliminary separator 4 has an aromatization product inlet connected to the aromatization product outlet at the bottom, a drain outlet at the bottom, a pyrolysis product inlet at the top, and a light component outlet connected to the light component inlet. A secondary separator 5 is used to perform the separation. The secondary separator 5 is provided with a mixed aromatic hydrocarbon inlet at the top and a light aromatic hydrocarbon outlet at the bottom. The secondary separator 5 is also provided with a heavy aromatic hydrocarbon outlet at the bottom. The cracking reactor 3 is used to carry out the cracking reaction. The bottom of the cracking reactor 3 is provided with a heavy aromatics inlet connected to the outlet of the heavy aromatics (C9+ aromatics), and the top is provided with a cracking product outlet connected to the inlet of the cracking product.

[0037] Example 2: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 is a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction is 5% Ni / SAPO-34. A methanol-containing reactant (100% methanol) is introduced into hydrocarbonation reactor 1, the reaction temperature is 450℃, the reaction pressure is 1.2 MPa, and the mass hourly space velocity (HHSV) is 1.0 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 99.5% or higher, the catalyst was considered to be stable. The final methanol conversion rate was 100%, and the olefin yield was 91 wt%.

[0038] The hydrocarbonation product was passed through aromatization reactor 2, with 4% Zn / ZSM-5 as the aromatization catalyst. The reaction temperature was 180℃, the reaction pressure was 1.2 MPa, and the mass hourly space velocity (WHSV) was 2.3 h⁻¹.-1 .

[0039] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated heavy aromatics, i.e., C9+ aromatics, are then fed into a cracking reactor 3. A 3% Pt / mordenite catalyst is used, and the reaction temperature is 560℃, the reaction pressure is 1.0 MPa, and the mass hourly space velocity (HHSV) is 1.0 h⁻¹. -1 .

[0040] The final yield of the mixed aromatics (sample taken from the BTX outlet of the secondary separator, and this description will be understood as the same hereafter) was 78.6 wt%, and the BTX yield was 67.7 wt%.

[0041] Example 3: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 is a fixed-bed reactor, and the catalyst for the hydrocarbonation reaction is 3% Zn / ZSM-5. A methanol-containing reactant (100% methanol) is introduced into hydrocarbonation reactor 1, the reaction temperature is 500℃, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (HHSV) is 2.0 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 99.5% or higher, the catalyst was considered to be stable. The final methanol conversion rate was 100%, and the olefin yield was 89 wt%.

[0042] The hydrocarbonation product was passed through aromatization reactor 2, with 5% Zr / ZSM-11 as the aromatization catalyst. The reaction temperature was 160℃, the reaction pressure was 1.0 MPa, and the mass space velocity was 1.5 h⁻¹. -1 .

[0043] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst is 6% Ni / β zeolite, the reaction temperature is 580℃, the reaction pressure is 2.0 MPa, and the mass hourly space velocity (HHSV) is 2.0 h⁻¹. -1 .

[0044] The final yield of mixed aromatics was 83.6 wt%, and the yield of BTX was 71.3 wt%.

[0045] Example 4: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 7% Zn / SAPO-34. A methanol-containing reactant (100% methanol) was introduced into hydrocarbonation reactor 1, the reaction temperature was 470℃, the reaction pressure was 1.3 MPa, and the mass hourly space velocity (HHSV) was 2.5 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 99.5% or higher, the catalyst was considered to be stable. The final methanol conversion rate was 100%, and the olefin yield was 87 wt%.

[0046] The hydrocarbonation product was passed through aromatization reactor 2, with 4% Mo / ZSM-12 as the aromatization catalyst. The reaction temperature was 200℃, the reaction pressure was 1.2 MPa, and the mass hourly space velocity (WHSV) was 3.2 h⁻¹. -1 .

[0047] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst used is 5% Cu / ZSM-5, the reaction temperature is 600℃, the reaction pressure is 1.7 MPa, and the mass hourly space velocity (HHSV) is 2.3 h⁻¹. -1 .

[0048] The final yield of mixed aromatics was 80.8 wt%, and the yield of BTX was 69.9 wt%.

[0049] Example 5: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 is a moving bed reactor, and the catalyst for the hydrocarbonation reaction is 2% Mo / ZSM-5. A methanol-containing reactant (100% methanol) is introduced into hydrocarbonation reactor 1, the reaction temperature is 450℃, the reaction pressure is 1.3 MPa, and the mass hourly space velocity (HHSV) is 3.5 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 99.5% or higher, the catalyst was considered to be stable. The final methanol conversion rate was 100%, and the olefin yield was 84 wt%.

[0050] The hydrocarbonation product was passed through aromatization reactor 2. The aromatization catalyst was 4% Zr / ZSM-11. The reaction temperature was 160℃, the reaction pressure was 0.8 MPa, and the mass space velocity was 2.5 h⁻¹. -1 .

[0051] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst is 7% Co / ZSM-5, the reaction temperature is 580℃, the reaction pressure is 1.0 MPa, and the mass hourly space velocity (HHSV) is 4.5 h⁻¹. -1 .

[0052] The final yield of mixed aromatics was 76.4 wt%, and the yield of BTX was 62.8 wt%.

[0053] Example 6: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 6% Ni / SAPO-18. A methanol-containing reactant (100% methanol) was introduced into hydrocarbonation reactor 1, the reaction temperature was 450℃, the reaction pressure was 1.2 MPa, and the mass hourly space velocity (HHSV) was 1.5 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 99% or higher, the catalyst was considered to be stable. The final methanol conversion rate was 100%, and the olefin yield was 86 wt%.

[0054] The hydrocarbonation product was passed through aromatization reactor 2. The aromatization catalyst was selected as 5% Zn / ZSM-11. The reaction temperature was 180℃, the reaction pressure was 1.2 MPa, and the reaction mass hourly space velocity was 2.5 h⁻¹. -1 .

[0055] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst used is 6% Ni / mordenite, the reaction temperature is 560℃, the reaction pressure is 1.2 MPa, and the mass hourly space velocity (HHSV) is 2.5 h⁻¹. -1 .

[0056] The final yield of mixed aromatics was 77.5 wt%, and the yield of BTX was 66 wt%.

[0057] Example 7: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 6% Zn / SAPO-34. A methanol-containing reactant (100% methanol) was introduced into hydrocarbonation reactor 1, the reaction temperature was 450℃, the reaction pressure was 1.1 MPa, and the mass hourly space velocity (HHSV) was 2.0 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 99.5% or higher, the catalyst was considered to be stable. The final methanol conversion rate was 100%, and the olefin yield was 82 wt%.

[0058] The hydrocarbonation product was passed through aromatization reactor 2, with 3% Zr / ZSM-5 as the aromatization catalyst. The reaction temperature was 160℃, the reaction pressure was 1.3 MPa, and the mass hourly space velocity (HHSV) was 2.8 h⁻¹.-1 .

[0059] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst used is 5% Fe / ZSM-5, the reaction temperature is 550℃, the reaction pressure is 1.4 MPa, and the mass hourly space velocity (HHSV) is 1.5 h⁻¹. -1 .

[0060] The final yield of mixed aromatics was 79.8 wt%, and the yield of BTX was 69.6 wt%.

[0061] Comparative Example 1: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 10% Mg / SAPO-34. A methanol-containing reactant (100% methanol) was introduced into hydrocarbonation reactor 1, the reaction temperature was 450℃, the reaction pressure was 1.2 MPa, and the mass hourly space velocity (HHSV) was 2.0 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 90% or above, the catalyst was considered to be stable. The final methanol conversion rate was 91%, and the olefin yield was 65 wt%.

[0062] The hydrocarbonation product was passed through aromatization reactor 2, with 5% Fe / ZSM-5 as the aromatization catalyst. The reaction temperature was 160℃, the reaction pressure was 0.8 MPa, and the mass hourly space velocity (WHSV) was 2.8 h⁻¹. -1 .

[0063] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst used is 10% Al / ZSM-5, the reaction temperature is 550℃, the reaction pressure is 1.4 MPa, and the mass hourly space velocity (HHSV) is 1.5 h⁻¹. -1 .

[0064] The final yield of mixed aromatics was 65 wt%, and the yield of BTX was 52.2 wt%.

[0065] Comparative Example 2: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 6% Zn / SAPO-34. A methanol-containing reactant (100% methanol) was introduced into hydrocarbonation reactor 1, the reaction temperature was 350℃, the reaction pressure was 0.8 MPa, and the mass hourly space velocity (HHSV) was 2.0 h⁻¹. -1Gas samples were collected at the outlet. When the methanol conversion rate reached 90% or above, the catalyst was considered to be stable. The final methanol conversion rate was 92%, and the olefin yield was 63 wt%.

[0066] The hydrocarbonation product was passed through aromatization reactor 2, with 5% Zr / ZSM-5 as the aromatization catalyst. The reaction temperature was 80℃, the reaction pressure was 1.3 MPa, and the mass hourly space velocity (HHSV) was 2.8 h⁻¹. -1 .

[0067] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst used is 5% Fe / ZSM-5, the reaction temperature is 400℃, the reaction pressure is 0.6 MPa, and the mass hourly space velocity (HHSV) is 1.5 h⁻¹. -1 .

[0068] The final yield of mixed aromatics was 58.3 wt%, and the yield of BTX was 32.3 wt%.

[0069] Comparative Example 3: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 4% Ni / SAPO-18. A methanol-containing reactant (100% methanol) was introduced into hydrocarbonation reactor 1, the reaction temperature was 450℃, the reaction pressure was 1.2 MPa, and the mass hourly space velocity (HHSV) was 1.5 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 90% or above, the catalyst was considered to be stable. The final methanol conversion rate was 94%, and the olefin yield was 66 wt%.

[0070] The hydrocarbonation product was passed through aromatization reactor 2. The aromatization catalyst was selected as 6% Zn / ZSM-11. The reaction temperature was 180℃, the reaction pressure was 1.2 MPa, and the reaction mass hourly space velocity was 2.5 h⁻¹. -1 .

[0071] The aromatization products are directly fed into secondary separator 5 for separation. The separated C9+ aromatics then enter cracking reactor 3. The catalyst selected is 5% Ni / mordenite, the reaction temperature is 560℃, the reaction pressure is 0.9 MPa, and the reaction mass hourly space velocity is 2.5 h⁻¹. -1 .

[0072] The final yield of mixed aromatics was 64.1 wt%, and the yield of BTX was 46.4 wt%.

[0073] Comparative Example 4: This embodiment provides a method for preparing aromatics from methanol, using the same equipment as in Example 1, and the specific steps include: Hydrocarbonation reactor 1 was selected as a fluidized bed reactor, and the catalyst for the hydrocarbonation reaction was 3% Zn / SAPO-34. A methanol-containing feedstock (80% methanol, 20% water) was introduced into hydrocarbonation reactor 1. The reaction temperature was 450℃, the reaction pressure was 1.5 MPa, and the mass hourly space velocity (HHSV) was 2.0 h⁻¹. -1 Gas samples were collected at the outlet. When the methanol conversion rate reached 90% or above, the catalyst was considered to be stable. The final methanol conversion rate was 96%, and the olefin yield was 67 wt%.

[0074] The hydrocarbonation product was passed through aromatization reactor 2, with 6% Zr / ZSM-5 as the aromatization catalyst. The reaction temperature was 160℃, the reaction pressure was 1.3 MPa, and the mass hourly space velocity (WHSV) was 2.8 h⁻¹. -1 .

[0075] The aromatization products are separated in a primary separator 4 and a secondary separator 5. The separated C9+ aromatics are then fed into a cracking reactor 3. The catalyst used is 8% Fe / ZSM-5, the reaction temperature is 550℃, the reaction pressure is 1.4 MPa, and the mass hourly space velocity (HHSV) is 1.5 h⁻¹. -1 .

[0076] The final yield of mixed aromatics was 68.5 wt%, and the yield of BTX was 55.8 wt%.

[0077] (1) This application discloses a three-stage reaction-two-stage separation method for preparing aromatics from methanol. This process, along with the selection of catalysts and the matching of reaction conditions for the three stages, successfully solves key technical bottlenecks in the methanol-to-aromatics process, such as complex reaction pathways, diverse intermediate products, numerous by-products, high energy consumption, and low BTX aromatics yield. It achieves gradient separation and directional conversion of reaction products, effectively suppressing side reactions and improving the purity and yield of the target product. Furthermore, it possesses the flexibility to independently control key process parameters such as reaction temperature, pressure, and space velocity, allowing for precise adjustment based on raw material characteristics and product requirements. This provides efficient and reliable technical support for the industrial production of methanol-to-aromatics. Specifically, the methanol conversion rate in this application reaches 100%, indicating that the raw materials are fully converted; the total aromatics yield exceeds 85 wt%, with the high-value-added BTX aromatics yield reaching over 70 wt%. These data fully verify the technological advancement of this process in the field of aromatics production, enabling efficient conversion of methanol into high-value-added aromatics products such as BTX, which are in high market demand, demonstrating significant economic feasibility.

[0078] (2) The method described in this application has advantages such as simple process and easy product separation, which can significantly reduce equipment investment and operating costs, thereby improving the overall economic benefits of the process. At the same time, the method has good adaptability to raw materials and can be compatible with methanol raw materials of different qualities, further broadening the raw material supply channels.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing aromatics from methanol, characterized in that, include: The alkylation reaction involves alkylating methanol with a catalyst to obtain the alkylation product. Aromatization reaction: The hydrocarbon product is subjected to an aromatization reaction in the presence of an aromatization catalyst to obtain the aromatized product. Preliminary separation: The aromatized products are preliminarily separated to obtain a light component, mixed aromatics and water. The light component is returned to the aromatization reaction step. The mixed aromatics are separated to obtain light aromatics and heavy aromatics; The cracking reaction involves cracking heavy aromatics in the presence of a cracking catalyst, and the resulting cracking products are returned to the preliminary separation step.

2. The method for preparing aromatics from methanol according to claim 1, characterized in that, The reactor used for the hydrocarbonation reaction is selected from one of a fixed-bed reactor, a moving-bed reactor, and a fluidized-bed reactor; And / or, the hydrocarbonation catalyst comprises a first active metal and a first molecular sieve support on which the first active metal is supported, wherein the first molecular sieve support is selected from at least one of SAPO-34 molecular sieve, SAPO-18 molecular sieve and ZSM-5 molecular sieve, and the first active metal is selected from at least one of Ni, Mo and Zn.

3. The method for preparing aromatics from methanol according to claim 1, characterized in that, The hydrocarbonation reaction is carried out at a temperature of 400-550°C, a pressure of 0.01-2.0 MPa, and a mass space velocity of 0.1-8 h -1 ; And / or, the olefin yield in the alkylation reaction is not less than 80 wt%.

4. The method for preparing aromatics from methanol according to claim 1, characterized in that, The reactor used for the aromatization reaction is a fixed-bed reactor; And / or, the aromatization reaction catalyst includes a second active metal and a second molecular sieve support on which the second active metal is supported, wherein the second molecular sieve support is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve and ZSM-12 molecular sieve, and the second active metal is selected from at least one of Zr, Zn, Cs and Mo.

5. The method for preparing aromatics from methanol according to claim 1, characterized in that, The aromatization reaction was carried out at a temperature of 160–350 °C, a pressure of 0.1–2.0 MPa, and a mass hourly space velocity of 0.1–8 h⁻¹. -1 .

6. The method for preparing aromatics from methanol according to claim 1, characterized in that, The reactor used for the pyrolysis reaction is a fluidized bed reactor; And / or, the cracking reaction catalyst comprises a hydrogenation active metal and a third molecular sieve support on which the hydrogenation active metal is supported, wherein the third molecular sieve support is selected from at least one of mordenite, ZSM-5 molecular sieve and β-zeolite, and the hydrogenation active metal is selected from at least one of Zn, Fe, Ni, Pt, Cu and Co.

7. The method for preparing aromatics from methanol according to claim 1, characterized in that, The pyrolysis reaction was carried out at a temperature of 500–700 °C, a pressure of 0.1–2.0 MPa, and a mass hourly space velocity (HHSV) of 0.1–8 h⁻¹. -1 .

8. The method for preparing aromatics from methanol according to claim 1, characterized in that, In the method for preparing aromatics from methanol, the conversion rate of methanol is above 99.5 wt%, the yield of aromatics is not less than 85 wt%, and the yield of BTX is not less than 70 wt%.

9. The method for preparing aromatics from methanol according to claim 1, characterized in that, The hydrocarbonation catalyst includes a first active metal and a first molecular sieve support loaded with the first active metal, wherein the first molecular sieve support is selected from at least one of SAPO-34 molecular sieve and ZSM-5 molecular sieve, and the first active metal is selected from at least one of Ni and Zn. And / or, the aromatization reaction catalyst comprises a second active metal and a second molecular sieve support loaded with the second active metal, wherein the second molecular sieve support is selected from ZSM-5 molecular sieve, and the second active metal is selected from at least one of Zr and Zn; And / or, the cracking reaction catalyst comprises a hydrogenation active metal and a third molecular sieve support on which the hydrogenation active metal is supported, wherein the third molecular sieve support is selected from ZSM-5 molecular sieve, and the hydrogenation active metal is selected from at least one of Zn, Fe, Ni, Pt, Cu and Co.

10. An apparatus used in the method for preparing aromatics from methanol according to any one of claims 1-9, characterized in that, include: A hydrocarbonation reactor is used to carry out the hydrocarbonation reaction. The hydrocarbonation reactor has a methanol inlet at the bottom and a hydrocarbonation product outlet at the top. An aromatization reactor is used to carry out the aromatization reaction. The top of the aromatization reactor is provided with a light component outlet and a hydrocarbon product inlet connected to the hydrocarbon product outlet, and the bottom is provided with an aromatization product outlet. A preliminary separator is provided for the preliminary separation. The preliminary separator has an aromatization product inlet connected to the aromatization product outlet at the bottom, a drain outlet at the bottom, a pyrolysis product inlet at the top, and a light component outlet connected to the light component inlet. A secondary separator is used to perform the separation. The secondary separator has a mixed aromatics inlet at the top, a light aromatics outlet at the bottom, and a heavy aromatics outlet at the bottom. A pyrolysis reactor is used to carry out the pyrolysis reaction. The bottom of the pyrolysis reactor is provided with a heavy aromatics inlet connected to the heavy aromatics outlet, and the top is provided with a pyrolysis product outlet connected to the pyrolysis product inlet.

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