Method and device for preparing olefin from methanol

Abstract

The present invention relates to the technical field of olefin preparation, and discloses a methanol-to-olefin method and apparatus, the method comprises: a) carrying out gas-solid separation on a product flow obtained by contacting methanol with a molecular sieve catalyst to obtain a spent catalyst and an olefin-containing gas phase product; and b) mixing a part of the spent catalyst serving as a circulating agent with a fresh catalyst, and returning to the reaction cavity in a rotational flow state to contact with methanol. According to the present invention, the defects of non-uniform catalyst mixing, poor fluidization state and low low-carbon olefin selectivity can be effectively eliminated.

Description

Technical Field

[0001] This invention relates to the field of olefin preparation technology, and more specifically to a method and apparatus for methanol-to-olefin production. Background Technology

[0002] Low-carbon olefins, namely ethylene and propylene, are two important basic chemical raw materials, and their demand is constantly increasing. Generally, ethylene and propylene are produced via the petroleum route, but due to the limited supply and high price of petroleum resources, the cost of producing ethylene and propylene from petroleum resources is constantly increasing. In recent years, efforts have been made to develop technologies for converting raw materials into ethylene and propylene. One important class of alternative raw materials for low-carbon olefin production are oxygen-containing compounds, such as alcohols (methanol, ethanol), ethers (dimethyl ether, methyl ethyl ether), and esters (dimethyl carbonate, methyl formate). These oxygen-containing compounds can be converted from energy sources such as coal, natural gas, and biomass. Some oxygen-containing compounds can already be produced on a large scale; for example, methanol can be produced from coal or natural gas using mature processes, achieving production scales of millions of tons. Due to the wide availability of oxygen-containing compounds and the economic viability of converting them into low-carbon olefins, processes for converting oxygen-containing compounds into olefins (OTO), especially methanol-to-olefins (MTO), are receiving increasing attention.

[0003] In existing technologies, the uneven distribution of the regenerated catalyst at the bottom of the methanol-to-olefins reactor leads to large fluctuations in bed temperature, which significantly affects the selection of dienes. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem in the prior art where the bottom regeneration catalyst distribution in the methanol-to-olefins reactor is uneven, resulting in large temperature fluctuations in the bed and a significant impact on the selection of dienes. This invention provides a method and apparatus for methanol-to-olefins that can effectively eliminate the defects of uneven catalyst mixing, poor fluidization state, and low selectivity for low-carbon olefins.

[0005] To achieve the above objectives, the present invention provides a method for methanol-to-olefins, the method comprising:

[0006] a) The product stream obtained by contacting methanol with the molecular sieve catalyst is subjected to gas-solid separation to obtain the catalyst to be generated and the gaseous product containing olefins.

[0007] b) A portion of the spent catalyst is mixed with the fresh catalyst as a recycling agent and returned to the reaction chamber in a swirling state to contact with methanol.

[0008] A second aspect of the present invention provides an apparatus for methanol-to-olefins, the apparatus comprising:

[0009] The reaction section is used to react methanol with a molecular sieve catalyst to obtain an olefin-containing product stream.

[0010] The separation section, connected to the reaction section, is used to perform gas-solid separation of the product stream to obtain the catalyst to be generated and the olefin-containing gaseous product.

[0011] The separation section and the reaction section are connected by an external circulation pipeline. The feed end of the external circulation pipeline is connected to the fresh catalyst port. The external circulation pipeline is equipped with a swirling structure so that the fresh catalyst entering the external circulation pipeline is mixed with the circulating agent and returned to the reaction section in a swirling state to contact methanol.

[0012] Through the above technical solutions, the present invention enhances the heat and mass transfer between raw materials by allowing the catalyst to enter the reaction chamber in a swirling state and fully contact it with methanol. Furthermore, the methanol-to-olefins apparatus of the present invention enhances the contact between the two materials by setting up a mixing structure and a swirling structure, and controls the flow field distribution to achieve mixing optimization, effectively suppressing uneven temperature distribution and low diene selectivity. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of a methanol-to-olefins apparatus according to some embodiments of the present invention;

[0014] Figure 2 This is a schematic diagram of the spiral component in a circulation pipe according to some embodiments of the present invention;

[0015] Figure 3 These are schematic diagrams of the structure of the spiral component according to some embodiments of the present invention;

[0016] Figure 4 yes Figure 3 A schematic diagram of the spiral component from another perspective;

[0017] Figure 5 This is a schematic diagram of the first layer mixing structure in the reaction chamber in some embodiments of the present invention;

[0018] Figure 6 This is a schematic diagram of the second layer mixing structure in the reaction chamber in some embodiments of the present invention;

[0019] Figure 7 This is a schematic diagram of the orthographic projection of two adjacent spiral components on the radial section of the circulation pipe in some embodiments of the present invention.

[0020] Explanation of reference numerals in the attached figures

[0021] 1 Methanol inlet; 2 Fresh catalyst inlet; 4 Cyclone separator gas outlet; 5 Catalyst pipe; 6 Reaction section; 7 Separation section; 8 Cyclone separator; 10 Circulation pipe; 12 Methanol distributor; 13 Mixing structure; 15 Riser; 16 Swirl structure; 19 Reaction chamber; 20 Settling chamber; 23 Spiral component; 231 Arc blade. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions. "Inner" and "outer" refer to the inner and outer contours of each component itself.

[0025] This invention provides a method for producing olefins from methanol, the method comprising:

[0026] a) The product stream obtained by contacting methanol with the molecular sieve catalyst is subjected to gas-solid separation to obtain the catalyst to be generated and the gaseous product containing olefins.

[0027] b) The remaining catalyst is used as a recycling agent and mixed with the fresh catalyst and returned to the reaction chamber in a swirling state. Compared with the existing technology of directly returning to the reaction chamber, the swirling return method can enhance the contact between the catalyst and methanol, improve the fluidization state of the material, and improve the selectivity of low carbon olefins.

[0028] In some embodiments of the present invention, the fresh catalyst and the circulating agent are circulated in the fluid by the eddies and centrifugal force generated by the swirling flow, thereby achieving enhanced mixing and maintaining the swirling state before returning to the reaction chamber to contact with methanol.

[0029] In some embodiments of the present invention, the pressure in the reaction chamber is 0-0.5 MPa and the average temperature is 350-560°C.

[0030] Catalysts commonly used in the prior art for reacting methanol to produce low-carbon olefins can be used in this invention. The following is an illustrative description, but it does not limit the scope of the invention. In some embodiments of the invention, the catalyst is SAPO-34, and the fluidized bed linear velocity U is 1-10 m / s, for example, 1 m / s, 2 m / s, 3 m / s, 4 m / s, 5 m / s, 6 m / s, 7 m / s, 8 m / s, 9 m / s, 10 m / s, preferably 2-10 m / s.

[0031] In some embodiments of the present invention, the fresh catalyst is derived from the regenerated catalyst.

[0032] In some embodiments of the present invention, the mass ratio of fresh catalyst to recycled catalyst is between 0.2 and 1, for example 0.2, 0.5, 0.8, 1.

[0033] In some embodiments of the present invention, a cyclone separator is used to perform gas-solid separation of the product stream.

[0034] This invention provides an apparatus for methanol-to-olefins, such as... Figure 1 As shown, the device includes:

[0035] Reaction section 6 is used to react methanol with molecular sieve catalyst to obtain olefin-containing product stream;

[0036] Separation section 7, connected to reaction section 6, is used to separate the product stream into gas and solid phases to obtain the catalyst to be generated and the olefin-containing gaseous product.

[0037] The separation section 7 and the reaction section 6 are connected by an external circulation pipeline. The feed end of the external circulation pipeline is connected to the fresh catalyst port 2. A swirling structure is provided in the external circulation pipeline so that the fresh catalyst entering the external circulation pipeline is mixed with the circulating agent and returned to the reaction section 6 in a swirling state to contact the methanol.

[0038] In some embodiments of the present invention, a swirling structure is provided in the external circulation pipeline to mix the fresh catalyst and the circulating agent through the eddies and centrifugal force generated by the swirling flow and maintain the swirling state before returning to the reaction chamber to contact methanol.

[0039] In some embodiments of the present invention, the separation section 7 is connected to the feed inlet of the catalyst regenerator to regenerate part of the catalyst to be regenerated to obtain a regenerator, and the discharge outlet of the regenerator is connected to the fresh catalyst outlet 2.

[0040] In some embodiments of the present invention, the top of the reaction chamber 19 tapers and the top opening extends upward into the settling chamber 20 of the separation section 7 to form a riser 15. Preferably, the distance between the outlet of the riser 15 and the bottom of the settling chamber 20 is 1 / 4H to 1 / 2H, where H is the height of the settling chamber 20.

[0041] In some embodiments of the present invention, the external circulation pipeline is configured as at least two circulation pipes 10 connecting the settling chamber 20 and the reaction chamber 19, preferably each circulation pipe 10 is equipped with a swirl structure 16.

[0042] In some embodiments of the present invention, the outlet of the circulation pipe 10 is connected to the side wall of the reaction chamber 19, the methanol inlet 1 is opened on the bottom wall of the reaction chamber 19, and a methanol distributor 12 is installed in the reaction chamber 19 located between the outlet of the circulation pipe 10 and the methanol inlet 1. The present invention has no special requirements for the methanol distributor and can use the gas distribution plate in the prior art. The present invention will not elaborate further on this.

[0043] Methanol reacts with a molecular sieve catalyst in reaction chamber 19 to produce a product gas of low-carbon olefins. The product gas and the entrained catalyst then enter a settling chamber 20 via a riser 15. A cyclone separator 8 in settling chamber 20 separates the product gas and the entrained catalyst. A portion of the separated catalyst is directly transported to reaction chamber 19 via a circulation pipe 10, while the other portion, after regeneration, is fed back into circulation pipe 10 for mixing and then returned to reaction chamber 19. In some embodiments of the invention, multiple cyclone separators 8 connected in series are installed in the settling chamber 20 of separation section 7 to perform multi-stage gas-solid separation of the product stream from reaction section 6. Specifically, the inlet of the first-stage cyclone separator is connected to the upper region of settling chamber 20, the gas outlet of the first-stage cyclone separator is connected to the inlet of the second-stage cyclone separator, and the product gas is obtained from the gas outlet 4 of the latter-stage cyclone separator. The solid outlets of all cyclone separators are connected to the middle region of settling chamber 20.

[0044] In some embodiments of the present invention, such as Figure 1 As shown, at least two layers of mixing structures 13, spaced apart along the height, are installed above the outlet of the circulation pipe 10 in the reaction chamber 19 to enhance the mixing between materials. In this invention, by installing a swirling structure 16 in the circulation pipe 10, the mixed catalyst particles enter the reaction chamber 19 from the side in a swirling state while the regenerator and the circulating agent are premixed, and come into contact with the methanol entering from the bottom. After passing through at least two layers of mixing structures, it should be noted that the MTO reaction is a rapid reaction. According to the structural arrangement of the methanol-to-olefins apparatus of this invention, all effective reaction space is mainly in the lower part of the reactor. Through at least two layers of mixing structures, the catalyst distribution and methanol can be made to contact as fully as possible at the bottom of the reactor, effectively suppressing uneven temperature distribution and low diene selectivity, thereby better solving the above-mentioned problems and making it suitable for industrial production of low-carbon olefins.

[0045] In some embodiments of the present invention, the mixing structure 13 and the swirling structure 16 each include multiple spiral elements 23. In the MTO process, since the reactivity of the two materials is relatively different, the mixing structure and the swirling structure enhance the contact between the two materials, optimize the uniformity of the internal temperature of the reactor, and effectively suppress side reactions.

[0046] To further improve diene selectivity, in some embodiments of the present invention, such as Figures 5-6 As shown, preferably from bottom to top, the number of spiral components 23 in the (i+1)th layer of the hybrid structure is 1 / 4 to 1 / 2 of that in the i-th layer, where i is an integer ≥ 1. It can be understood that the uniform distribution of the multiple spiral components 23 in each layer of the hybrid structure can, for example, be a circumferentially distributed arrangement on the same plane at equal intervals. That is, the multiple spiral components 23 form multiple spiral rings concentrically arranged on the same plane, and each spiral ring includes multiple spiral components 23 arranged at equal intervals along the circumferential direction.

[0047] To further improve diene selectivity, in some embodiments of the present invention, N spiral components 23 are uniformly distributed in the first layer of the mixed structure 13 from bottom to top, where N≥k*U*π*D*ε / (d*L), k is a correction coefficient of 0.00895, U is the fluidized bed linear velocity, ε is the bed porosity, D is the diameter of the reaction chamber body, d is the maximum dimension of the spiral component 23 in the radial direction of the reaction chamber, and L is the distance between the first layer and the second layer of the mixed structure 13.

[0048] In some embodiments of the present invention, N ≥ 4 is preferred.

[0049] In some embodiments of the present invention, such as Figures 2-3 As shown, the swirl structure 16 includes at least two helical elements 23, wherein the arrangement of the at least two helical elements 23 in the circulation pipe 10 includes form one or form two:

[0050] Form 1: At least two spiral components 23 are evenly arranged on the same cross section of the circulation pipe 10. In this invention, there are no special requirements for the uniform arrangement of the spiral components 23. As long as they can be evenly distributed on the same cross section of the vertical central axis of the circulation pipe, the spiral component arrangement in the hybrid structure of this invention can be adopted.

[0051] Form 2: At least two spiral components 23 are arranged at intervals along the central axis of the circulation pipe 10, and along the flow direction of the material in the circulation pipe 10, such as... Figure 7 As shown, in two adjacent spiral members 23, the next spiral member 23 and the previous spiral member 23 have a misalignment angle α on the radial cross section of the circulation tube 10; in some embodiments of the present invention, the range of α can be 0-45°.

[0052] The swirling structure 16 of the present invention enables the swirling mixing of the catalyst to be generated and the regenerator, and also allows the mixed catalyst to enter the reaction chamber in a swirling state and disperse rapidly to contact the raw material gas.

[0053] In some embodiments of the present invention, such as Figures 3-4 As shown, the spiral component 23 includes at least two arc-shaped blades 231, the bottom ends of which are connected and the top ends are far apart from each other, as shown. Figures 3-4 As shown, for example, the spiral component 23 can be made of a thin sheet material with a semi-circular end. Along the overall axial direction, the thin sheet is cut from the semi-circular end but not completely cut off to form two blades with connected bottom ends. These two blades are bent in a direction away from each other to form two arc-shaped blades 231 with their top ends far apart, so that the spiral component 23 forms an approximate "γ" shape. Under the action of airflow, the catalyst runs from the lower end of the spiral component 23 to the arc-shaped blades, which can avoid the collision and wear of the catalyst as much as possible. Compared with the conventional right-angle baffle separation structure or threaded separation structure in the prior art, the structure of the spiral component 23 of the present invention can achieve low pressure drop and fast mixing to prepare low-carbon olefins.

[0054] In some embodiments of the present invention, the spiral component 23 includes two arc-shaped blades 231, and the included angle θ formed by the two arc-shaped blades is 30°≤θ≤150°.

[0055] The advantages of the present invention will be illustrated by the following examples, but the present invention is not limited thereto.

[0056] Example 1

[0057] This embodiment adopts Figures 1-7 The methanol-to-olefins (MTO) apparatus includes a reaction section 6 and a separation section 7 connected to each other. The separation section 7 is connected to the inlet of a catalyst regenerator. The top outlet of the reaction chamber 19 in the reaction section 6 extends upward into the settling chamber 20 of the separation section 7 to form a riser 15. The inlet end of the circulation pipe 10 is connected to the settling chamber 20 and the regenerator, and the outlet end of the circulation pipe 10 is connected to the reaction chamber 19. A swirl structure 16 is provided in the circulation pipe 10. The outlet of the circulation pipe 10 is connected to the side wall of the reaction chamber 19. A methanol inlet 1 is opened on the bottom wall of the reaction chamber 19. A gas distribution plate is installed in the reaction chamber 19 located between the outlet of the circulation pipe 10 and the methanol inlet 1. Two layers of mixing structures 13 are arranged at intervals along the height direction in the reaction chamber 19 located above the outlet of the circulation pipe 10. Multiple cyclone separators 8 connected in series are installed in the settling chamber 20. The inlet of the first-stage cyclone separator is connected to the upper section of the settling chamber 20, and the gas outlet of the first-stage cyclone separator is connected to the inlet of the second-stage cyclone separator. Product gas is obtained from the gas outlet 4 of the next-stage cyclone separator. The solid outlets of all cyclone separators are connected to the middle section of the settling chamber 20.

[0058] The distance between the outlet of the riser 15 and the bottom of the settling chamber 20 is 1 / 2H, where H is the height of the settling chamber 20; the mixing structure 13 and the swirling structure 16 each include multiple spiral components 23, each spiral component 23 including two arc-shaped blades 231, the bottom ends of the arc-shaped blades 231 are connected, and the top ends are far apart from each other, the included angle θ formed by the two arc-shaped blades is 150°, two spiral components 23 are installed in each circulation pipe 10, and along the flow direction of the material in the circulation pipe 10, the next spiral component 23 and the previous spiral component 23 have a misalignment angle α of 15° on the radial section of the circulation pipe 10; the reaction chamber In the first layer of the mixed structure, the spiral components 23 are evenly distributed in a circular pattern on the same plane. The number of spiral components 23 in the second layer of the mixed structure is half that of the first layer. In the first layer of the mixed structure 13, N spiral components 23 are evenly distributed, N≥k*U*π*D*ε / (d*L), where the correction coefficient k is 0.00895, the fluidized bed linear velocity U is 2m / s, the bed porosity ε is 0.45, the diameter D of the reaction chamber is 10m, the maximum dimension d of the spiral component 23 in the radial direction of the reaction chamber is 1 / 20D, the distance L between the first and second layers of the mixed structure 13 is 0.5d, and N is 6.

[0059] The method for methanol-to-olefins (MTO) includes: reacting 95% pure methanol feed gas with a molecular sieve catalyst in reaction chamber 19 to obtain low-carbon olefins as product gas, and the entrained spent catalyst entering settling chamber 20 via riser 15. Cyclone separator 8 in settling chamber 20 separates the product gas and the entrained spent catalyst. A portion of the separated spent catalyst is used as a recirculating agent and directly enters reaction chamber 19 via circulation pipe 10. The other portion is regenerated and enters recirculating agent via circulation pipe 10, where it is mixed with the recirculating agent via swirl structure 16 before returning to reaction chamber 19. The pressure in the reaction chamber is 0.1 MPa, the average temperature is 450℃, the catalyst is SAPO-34, the total amount is 300 tons, and the mass ratio of regenerated agent to recirculating agent is 0.5.

[0060] Results: The reactor bed temperature difference was 3℃, the methanol conversion rate was 99.97%, and the total yield (mass) of ethylene and propylene was 87.2%.

[0061] Example 2

[0062] Unlike Example 1, and along the flow direction of the material in the circulation pipe 10, the next spiral component 23 and the previous spiral component 23 have a misalignment angle α of 15° on the radial section of the circulation pipe 10. The distance between the outlet of the riser pipe 15 and the bottom of the settling chamber 20 is 1 / 2H. The included angle θ formed by the two arc-shaped blades is 90°. From bottom to top, the number of spiral components 23 in the second layer of the mixing structure is 1 / 2 of that in the first layer. Among them, N spiral components 23 are uniformly distributed in the first layer of the mixing structure 13, N≥k*U*π*D*ε / (d*L), where the correction coefficient k is 0.00895, the fluidized bed linear velocity U is 2m / s, the bed porosity ε is 0.45, the diameter D of the reaction chamber body is 10m, the maximum dimension d of the spiral component 23 in the radial direction of the reaction chamber is 1 / 20D, the distance L between the first layer and the second layer of the mixing structure 13 is 0.5d, and N is 6.

[0063] The pressure in the reaction chamber is 0.1 MPa, the average temperature is 450℃, and the catalyst is SAPO-34. The mass ratio of regenerator to recycled agent is 0.5.

[0064] Results: The reactor bed temperature difference was 4℃, the methanol conversion rate was 99.96%, and the total yield (mass) of ethylene and propylene was 86.8%.

[0065] Example 3

[0066] Unlike Example 1, and along the flow direction of the material in the circulation pipe 10, the next spiral component 23 and the previous spiral component 23 have a misalignment angle α of 15° on the radial section of the circulation pipe 10. The distance between the outlet of the riser pipe 15 and the bottom of the settling chamber 20 is 1 / 2H. The included angle θ formed by the two arc-shaped blades is 30°. From bottom to top, the number of spiral components 23 in the second layer of the mixing structure is 1 / 4 of that in the first layer. Among them, N spiral components 23 are evenly distributed in the first layer of the mixing structure 13, N≥k*U*π*D*ε / (d*L), where the correction coefficient k is 0.00895, the fluidized bed linear velocity U is 2m / s, the bed porosity ε is 0.45, the diameter D of the reaction chamber body is 10m, the maximum dimension d of the spiral component 23 in the radial direction of the reaction chamber is 1 / 20D, the distance L between the first layer and the second layer of the mixing structure 13 is 0.5d, and N is 4.

[0067] The pressure in the reaction chamber is 0.1 MPa and the average temperature is 450℃; the catalyst is SAPO-34 and the mass ratio of regenerator to circulating agent is 0.5.

[0068] Results: The reactor bed temperature difference was 4.5℃, the methanol conversion rate was 99.955%, and the total yield (mass) of ethylene and propylene was 86.6%.

[0069] Example 4

[0070] Unlike Example 1, the mass ratio of regenerator to recycling agent is 0.1.

[0071] Results: The reactor bed temperature difference was 4.5℃, the methanol conversion rate was 94.14%, and the total yield (mass) of ethylene and propylene was 80.75%.

[0072] Example 5

[0073] Unlike Example 1, the distance between the outlet of the riser pipe 15 and the bottom of the settling chamber 20 is 1 / 8H.

[0074] Results: The reactor bed temperature difference was 12℃, the methanol conversion rate was 98.921%, and the total yield (mass) of ethylene and propylene was 81.2%.

[0075] Example 6

[0076] Unlike Example 1, the number of spiral elements 23 in the hybrid structure of the second layer is the same as that in the first layer.

[0077] Results: The reactor bed temperature difference was 8℃, the methanol conversion rate was 99.921%, and the total yield (mass) of ethylene and propylene was 81.8%.

[0078] Example 7

[0079] Unlike Example 1, N is 2, which means that N≥k*U*π*D*ε / (d*L) is not satisfied.

[0080] Results: The reactor bed temperature difference was 16℃, the methanol conversion rate was 97.921%, and the total yield (mass) of ethylene and propylene was 80.3%.

[0081] Example 8

[0082] Unlike Example 1, θ is 15°.

[0083] Results: The reactor bed temperature difference was 25℃, the methanol conversion rate was 96.995%, and the total yield (mass) of ethylene and propylene was 80.2%.

[0084] Example 9

[0085] Unlike Example 1, a screw element, as used in the prior art, is installed in the circulation pipe 10. The screw is used to mix the regenerant and the circulating agent and feed them into the reaction chamber.

[0086] Results: The reactor bed temperature difference was 30℃, the methanol conversion rate was 95.985%, and the total yield (mass) of ethylene and propylene was 79.5%.

[0087] Comparative Example 1

[0088] The methanol-to-olefins apparatus and reaction method with catalyst mixer disclosed in CN 105561895 A were used to prepare olefins using the same raw materials and catalyst as in Example 1. The average temperature was 480°C, the gas phase linear velocity was 0.5 m / s, the temperature in the catalyst mixer was 480°C, and the reaction pressure was 0.1 MPa (gauge pressure).

[0089] Results: With a bed temperature difference of 15℃, the methanol conversion rate was 95.2%, and the total yield (by mass) of ethylene and propylene at the reactor outlet was 85.029%.

[0090] Comparative Example 2

[0091] The methanol-to-olefins apparatus and reaction method with catalyst mixer disclosed in CN 105561895 A were used to prepare olefins using the same raw materials and catalyst as in Example 1. The average temperature was 480°C, the gas phase linear velocity was 2 m / s, the temperature in the catalyst mixer was 480°C, and the reaction pressure was 0.1 MPa (gauge pressure).

[0092] Results: The bed temperature difference was 18℃, the methanol conversion rate was 95.5%, and the total yield (mass) of ethylene and propylene at the reactor outlet was 78.24%.

[0093] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing olefins from methanol, characterized in that, The method includes: a) The product stream obtained by contacting methanol with the molecular sieve catalyst is subjected to gas-solid separation to obtain the catalyst to be generated and the gaseous product containing olefins. b) A portion of the spent catalyst is mixed with the fresh catalyst as a recycling agent and returned to the reaction chamber in a swirling state to contact with methanol.

2. The method according to claim 1, wherein, The fresh catalyst is mixed with the circulating agent by a vortex generated by swirl and centrifugal force, and returned to the reaction chamber in a swirling state to contact methanol; and / or The pressure in the reaction chamber is 0-0.5 MPa, and the average temperature is 350-560℃; and / or The catalyst includes SAPO-34, and the fluidized bed linear velocity U is 1-10 m / s; and / or The fresh catalyst is derived from the regenerated catalyst.

3. The method according to claim 1 or 2, wherein, The mass ratio of fresh catalyst to recycled catalyst is between 0.2 and 1; and / or A cyclone separator is used to perform gas-solid separation on the product stream.

4. An apparatus for methanol-to-olefins production, characterized in that, The device includes: The reaction section (6) is used to react methanol with the molecular sieve catalyst to obtain an olefin-containing product stream; The separation section (7) is connected to the reaction section (6) and is used to perform gas-solid separation of the product stream to obtain the catalyst to be generated and the gas phase product containing olefins. The separation section (7) and the reaction section (6) are connected by an external circulation pipeline. The feed end of the external circulation pipeline is connected to the fresh catalyst port (2). The external circulation pipeline is provided with a swirling structure so that the fresh catalyst entering the external circulation pipeline is mixed with the circulating agent and returned to the reaction section (6) in a swirling state to contact with methanol.

5. The apparatus according to claim 4, characterized in that, The separation section (7) is connected to the inlet of the catalyst regenerator to regenerate a portion of the catalyst to be regenerated into a regenerator, and the outlet of the regenerator is connected to the inlet (2) of the fresh catalyst; and / or The top outlet of the reaction chamber (19) of the reaction section (6) extends upward into the settling chamber (20) of the separation section (7) to form a riser (15). Preferably, the distance between the outlet of the riser (15) and the bottom of the settling chamber (20) is 1 / 4H to 1 / 2H, where H is the height of the settling chamber (20); and / or The external circulation pipeline is configured as at least two circulation pipes (10) connecting the settling chamber (20) and the reaction chamber (19), preferably each circulation pipe (10) is equipped with the swirling structure (16); and / or The separation section (7) is equipped with multiple cyclone separators (8) connected in series for multi-stage gas-solid separation of the product stream from the reaction section (6).

6. The apparatus according to claim 4 or 5, characterized in that, At least two layers of mixing structures (13) arranged at intervals along the height direction are installed in the reaction chamber (19) above the outlet of the circulation pipe (10) to enhance the mixing of material components; and / or A methanol distributor (12) is installed in the reaction chamber (19) located below the outlet of the circulation pipe.

7. The apparatus according to any one of claims 4-6, characterized in that, The hybrid structure (13) and the swirling structure (16) each include multiple helical elements (23); Preferably, from bottom to top, the number of spiral components (23) in the hybrid structure of the (i+1)th layer is 1 / 4 to 1 / 2 of that of the i-th layer, where i is an integer ≥1.

8. The apparatus according to any one of claims 4-7, characterized in that, N spiral components (23) are evenly distributed in the first layer of the mixed structure (13) from bottom to top, N≥k*U*π*D*ε / (d*L), where k is the correction coefficient 0.00895, U is the fluidized bed linear velocity in m / s, ε is the bed porosity, D is the diameter of the main body of the reaction chamber in m, d is the maximum dimension of the spiral component (23) in the radial direction of the reaction chamber in m, and L is the distance between the first layer and the second layer of the mixed structure (13) in m; Ideally, N ≥ 4.

9. The apparatus according to any one of claims 4-8, characterized in that, The helical component (23) includes at least two arcuate blades (231), the bottom ends of which are connected and the top ends are far apart from each other; and / or The spiral component (23) includes two arc-shaped blades (231), and the included angle θ formed by the two arc-shaped blades is 30°≤θ≤150°.

10. The apparatus according to any one of claims 4-9, characterized in that, The swirl structure (16) includes at least two helical elements (23), wherein the arrangement of the at least two helical elements (23) in the circulation pipe (10) includes: At least the two spiral components (23) are evenly arranged at the same cross section of the circulation pipe (10); or At least two spiral components (23) are arranged at intervals along the central axis of the circulation pipe (10), and the orthographic projections of two adjacent spiral components (23) on the radial section of the circulation pipe (10) have a misalignment angle α, the range of α being 0 to 45°.

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