MTO (methanol to olefin) device and method for preparing low-carbon olefin from methanol

Abstract

The invention relates to the field of chemical engineering, in particular to the field of preparation of olefins from methanol, and discloses an MTO device and a method for preparing low-carbon olefins from methanol, the MTO device comprises a reactor, N (N > = 1) reaction tubes are arranged in a reaction cavity of the reactor, each reaction tube comprises a supporting layer, a cavity defined by the supporting layers in a surrounding mode forms a product flow channel, and the product flow channel is communicated with the reactor. A catalyst layer is arranged outside the supporting layer, a raw material inlet of the reactor is communicated with the reaction cavity, and a product flow channel of each reaction tube is communicated with a discharging part of the reactor; wherein methanol fed through the raw material inlet is in contact with the catalyst layer, and a product obtained after reaction enters the product flow channel through the supporting layer. The problems of non-uniform catalyst distribution, overlong contact time of raw materials and the catalyst and low yield of low-carbon olefin in the prior art can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical equipment, and particularly relates to an MTO device and a method for producing lower olefins from methanol. Background Art

[0002] Lower olefins, namely ethylene and propylene, are two important basic chemical raw materials, and their demand is increasing continuously. Generally, ethylene and propylene are produced through the petroleum route. However, due to the limited supply and high price of petroleum resources, the cost of producing ethylene and propylene from petroleum resources is increasing continuously. In recent years, people have begun to vigorously develop technologies for converting alternative raw materials into ethylene and propylene.

[0003] US 6166282 A discloses a technology and reactor for converting oxides into lower olefins. A fast fluidized bed reactor is adopted. After the gas phase completes the reaction in the dense-phase reaction zone with a lower gas velocity, it rises to the fast zone where the inner diameter rapidly decreases, and then a special gas-solid separation device is used to preliminarily separate out most of the entrained catalyst. Since the product gas and the catalyst are rapidly separated after the reaction, the occurrence of secondary reactions is effectively prevented. However, this method still has the problem of low yield of lower olefins.

[0004] CN 1723262 A discloses a multi-stage riser reaction device with a central catalyst loop for the process of converting oxides into lower olefins. This set of devices includes multiple riser reactors, a gas-solid separation zone, multiple offset elements, etc. Each riser reactor has its own port for injecting catalyst, which converges to the set separation zone to separate the catalyst from the product gas. However, this method still has the problem of low yield of lower olefins.

[0005] US 6166282 A discloses a technology and reactor for converting methanol into lower olefins. A fast fluidized bed reactor is adopted. After the gas phase completes the reaction in the dense-phase reaction zone with a lower gas velocity, it rises to the fast zone where the inner diameter rapidly decreases, and then a special gas-solid separation device is used to preliminarily separate out most of the entrained catalyst. Since the product gas and the catalyst are rapidly separated after the reaction, the occurrence of secondary reactions is effectively prevented. Through simulation calculations, compared with the traditional bubbling fluidized bed reactor, the inner diameter of this fast fluidized bed reactor and the catalyst inventory required are both greatly reduced. However, this method has the problem of low yield of lower olefins.

[0006] The existing technologies all have the problem of low yield of lower olefins. The present invention specifically solves this problem. Summary of the Invention

[0007] The object of the present invention is to overcome the problems existing in the prior art of methanol to olefins, such as uneven catalyst distribution, excessive contact time between raw materials and catalyst, and low yield of light olefins, and to provide an MTO device and a method for producing light olefins from methanol, so that energy transfer, reaction and rapid separation can be achieved under the action of the flow field for the raw materials.

[0008] To achieve the above object, on the one hand, the present invention provides an MTO device, which includes a reactor. In the reaction chamber of the reactor, N (N≥1) reaction tubes are arranged. The reaction tubes include a support layer, and the cavity surrounded by the support layer forms a product flow channel. A catalyst layer is arranged outside the support layer. The raw material inlet of the reactor is communicated with the reaction chamber, and the product flow channel of each reaction tube is communicated with the discharge part of the reactor;

[0009] Among them, methanol fed through the raw material inlet contacts with the catalyst layer, and the reaction product passes through the support layer and enters the product flow channel.

[0010] On the second aspect, the present invention provides a method for producing light olefins from methanol. The method uses the reaction device MTO device of the present invention, including feeding gaseous methanol into the reaction chamber of the reactor through the raw material inlet, making the gaseous methanol contact with the catalyst on the reaction tube to obtain light olefins, and making the light olefins enter the product flow channel and discharge the reactor through the pressure difference inside and outside the reaction tube.

[0011] Through the above technical solutions, the present invention mainly solves the problems existing in the prior art of methanol to olefins, such as uneven catalyst distribution, excessive contact time between raw materials and catalyst, and low yield of light olefins. The present invention uniformly coats the catalyst on the reaction tube, and energy transfer, reaction and rapid separation are achieved under the action of the flow field for the raw materials; further, by adding segmented isolation plates inside the device, the flow field in the reactor is optimized; further, the MTO device is modularly designed, which is convenient for improving the olefin yield and enlarging the production capacity, overcomes the problems of separation and low olefin yield in the existing reactor, and can be used in the industrial production of light olefins. Description of the Drawings

[0012] Figure 1 is a connection schematic diagram of the MTO device in some embodiments of the present invention;

[0013] Figure 2 is Figure 1 the structural schematic diagram of the reactor in

[0014] Figure 3 is Figure 2 the structural schematic diagram of the reaction tube in

[0015] Description of the Reference Numerals

[0016] 1 Methanol / regenerated gas; 2 Unreacted methanol / regenerated gas after passing through the reactor; 3 Product discharge pipeline; 4 Reactor; 5 Pressure regulator; 6 Raw material inlet; 7 Raw material outlet; 8 First flange; 9 Second flange; 10 Partition plate; 11 Reaction tube; 12 Product outlet; 13 Catalyst layer; 14 Support layer; 15 Product flow channel. Detailed implementation manners

[0017] The following will describe in detail the specific implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0018] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0019] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are generally in the direction shown in the accompanying drawings or in the vertical, perpendicular or gravitational direction for describing the relative positional relationship of each component, and "inner, outer" refer to the inner and outer of the contour of each component itself.

[0020] The present invention discloses an MTO device, as Figure 2 shown, the MTO device includes a reactor 4, and N (N≥1) reaction tubes 11 are arranged in the reaction cavity of the reactor 4, as Figure 3 shown, the reaction tube 11 includes a support layer 14 and a catalyst layer 13 from the inside to the outside. Among them, the support layer 14 forms a product flow channel 15 around the defined cavity shape, and the support layer 14 is provided with a product discharge part communicating with the product flow channel 15. The raw material inlet 6 of the reactor 4 communicates with the reaction cavity, and the product discharge part of each reaction tube 11 communicates with the discharge part of the reactor 4;

[0021] Among them, the methanol fed through the raw material inlet 6 contacts the catalyst layer 13, and the reaction product passes through the support layer 14 and enters the product flow channel 15.

[0022] It should be noted that the catalyst is coated on the support layer 14. Compared with the fluidized gas-solid contact method in the prior art, the catalyst distribution is more uniform. Methanol contacts the catalyst and enters the product flow channel 15 through the pores in the catalyst layer and the pores in the support layer 14. In this way, energy transfer, reaction, and rapid separation can be achieved. Among them, the support layer surrounding the defined cavity can be set to be closed at both ends, and a material port communicating with the product flow channel 15 is opened on the support layer, and this discharge port forms a product discharge part. Or, one end of the cavity is closed, and the end face at the other end is opened to form a product discharge part.

[0023] In the present invention, conventional catalyst coating methods are applicable to the present invention. For example, the high-efficiency spraying equipment for a purification catalyst in CN201721428487.9 in the prior art can be adopted.

[0024] In some embodiments of the present invention, the porosity of the support layer 14 is 20-45%. Thus, it has excellent gas permeation amount and can improve the yield of the target product.

[0025] In some embodiments of the present invention, the pore diameter in the support layer 14 is 20-100 nm. Thus, it has excellent support for the catalyst coating film.

[0026] In some embodiments of the present invention, the material of the support layer 14 includes at least one of aluminum oxide, silicon carbide, or stainless steel sintered film. It can be understood that since alumina has acid and alkali resistance and a mature preparation process, alumina material is preferably used.

[0027] In some embodiments of the present invention, the thickness of the catalyst in the catalyst layer 13 is 20-100 μm.

[0028] In some embodiments of the present invention, the particle diameter in the catalyst layer 13 is 50-5000 nm.

[0029] In some embodiments of the present invention, the axis of the reaction tube 11 is arranged parallel to the axis of the reaction cavity, and N reaction tubes 11 are arranged at intervals; preferably N≥0.8*(diameter of the reactor 4 / diameter of the reaction tube 11), and N is rounded to an integer.

[0030] In some embodiments of the present invention, as Figure 2 shown, a raw material inlet 6 and a raw material outlet 7 are opened on the wall of the reactor 4. Among them, the raw material inlet 6 is opened on the wall of the reactor 4 at one end far from the product discharge part of the reaction tube 11, and the raw material outlet 7 is opened on the wall of the reactor 4 at one end close to the product discharge part of the reaction tube 11.

[0031] In some embodiments of the present invention, the reaction tube is fixed in the reaction cavity through a flange, as Figure 2As shown in the figure, the flange includes a first flange 8 and a second flange 9 provided at both ends of the reaction chamber. Both ends of the reaction tube are respectively connected to the first flange 8 and the second flange 9. Among them, the second flange 9 divides the reaction chamber into two non - communicating first space and second space. Among them, the product outlet 12 is opened on the chamber wall of the second space, and the product discharging part of the reaction tube is located in the second space. The raw material inlet 6 and the raw material outlet 7 are opened on the chamber wall of the first space and are located at both ends of the first space. In this way, the raw materials enter the reaction chamber from the raw material inlet 6 to contact and react with the catalyst. The reacted products are discharged from the product outlet 12, and the unreacted raw materials are discharged from the raw material outlet 7.

[0032] To optimize the flow field in the reaction chamber, in some embodiments of the present invention, as Figure 2 shown in the figure, along the axial direction, a plurality of partition plates 10 are staggeredly arranged at intervals in the reaction chamber. One side of each partition plate is tightly connected to the chamber wall, and the other side is spaced from the chamber wall so that the material can flow in the reaction chamber. The reaction tube 11 penetrates through the partition plate 10. Among them, the raw material inlet 6 is opened between the first flange 8 and the partition plate 10 adjacent to the first flange 8, and the raw material outlet 7 is opened between the second flange 9 and the partition plate 10 adjacent to the second flange 9. In this way, the reaction materials flow from the raw material inlet to the raw material outlet through the gaps formed between the flange and the partition plate, and between the partition plates.

[0033] In some embodiments of the present invention, it is preferred that the ratio of the length of the partition plate 10 in the radial direction of the reactor 4 to the diameter of the reactor 4 is 1:1 - 5.

[0034] In some embodiments of the present invention, it is preferred that the number of the partition plates 10 is an integer of the ratio of the length to the diameter of the reactor 4.

[0035] In some embodiments of the present invention, the MTO device includes an additional pressure regulator 5. The product discharging part of each reaction tube 11 is communicated with the pressure regulator 5. Specifically, for example, the pressure regulator 5 is communicated with the product discharging part of each reaction tube 11 through the product outlet 12 opened on the reactor 4. The pressure regulator 5 is provided with a product discharge pipeline 3.

[0036] For the present invention, there is no special requirement for the pressure regulator 5, as long as the required pressure adjustment can be achieved. The following is a demonstration, but does not limit the scope of the present invention for this reason. In some embodiments of the present invention, the pressure regulator 5 includes a vacuum pump and / or a blower.

[0037] To facilitate the amplification of production capacity, in some embodiments of the present invention, at least two reactors 4 are provided. The reactors 4 are connected in series or in parallel. In this way, modularization, production capacity amplification and yield improvement of the MTO device can be achieved. It can be understood that, as Figure 1As shown, when multiple reactors are connected in series, in two adjacent reactors, the raw material outlet 7 in the previous reactor is connected to the raw material inlet of the next reactor, and the product outlet 12 of each reactor is connected to the pressure regulator 5. Alternatively, the product outlets of the reactors are connected in series in sequence and finally connected to the pressure regulator 5. The present invention has no special requirements for this and will not be elaborated further.

[0038] Based on the foregoing disclosure, the present invention discloses a method for producing lower olefins from methanol. This method uses the MTO device of the present invention, including feeding gaseous methanol into the reaction chamber of the reactor 4 through the raw material inlet 6, contacting the gaseous methanol with the catalyst on the reaction tube 11 to obtain lower olefins, and enabling the lower olefins to enter the product flow channel 15 and be discharged from the reactor through the pressure difference inside and outside the reaction tube 11.

[0039] In this way, the lower olefins generated after the raw material contacts the catalyst directly penetrate the tube wall of the reaction tube and enter the product flow channel 15, which can avoid the problem of excessive contact time between the raw material and the catalyst. Moreover, the catalyst is coated on the reaction tube using the prior art, which can avoid the problem of uneven catalyst distribution compared with the existing methods for preparing lower olefins.

[0040] In some embodiments of the present invention, the reaction conditions include: the pressure in the reactor 4 is 0 - 0.3 MPa in gauge pressure, the average temperature is 350 - 560 °C, the temperature difference < 5 °C, and the material linear velocity in the reactor 4 is 1 - 10 m / s.

[0041] In some embodiments of the present invention, the vacuum degree of the product outlet 12 of the reactor 4 is controlled at 500 - 4000 Pa.

[0042] In the present invention, the catalysts for conventionally preparing lower olefins are all applicable to the present invention. The following is a demonstration but does not limit the scope of the present invention. In some embodiments of the present invention, the catalyst includes at least one of SAPO - 34, SAPO - 44, SAPO - 47, or ZSM - 5.

[0043] In the present invention, the raw materials for conventionally preparing lower olefins are not limited to methanol only. For example, gaseous ethanol, dimethyl ether, or methyl formate are all applicable to the present invention, and the present invention will not elaborate on this further.

[0044] In some embodiments of the present invention, when the catalyst activity decreases, the gaseous methanol is replaced with a regeneration gas to regenerate the catalyst. Among them, when the diene yield in the product is lower than 75%, it is determined that the catalyst activity is low. The present invention has no special requirements for the regeneration gas of the catalyst, and the regeneration gas and regeneration conditions for conventionally regenerating catalysts for preparing lower olefins can all be used in the present invention. For example, the regeneration gas can be selected from oxygen, CO 2 or H 2At least one of O, and the regeneration conditions include introducing regeneration gas through the raw material inlet 6 at 550-650°C. After the gas composition at the raw material outlet 7 (if multiple reactors are connected in series, the raw material outlet 7 of the last reactor) is stable, the regeneration ends.

[0045] The advantages of the present invention will be illustrated by the following examples, but the present invention is not limited thereto.

[0046] Example 1

[0047] Adopt an MTO device as Figure 1 - Figure 2 shown. The MTO device includes a vacuum pump and 4 reactors 4 connected in series. In the reaction chamber of each reactor 4, multiple reaction tubes 11 are provided. The axis of the reaction tube 11 is arranged parallel to the axis of the reaction chamber. The reaction tube is fixed in the reaction chamber through the first flange 8 and the second flange 9. The second flange 9 divides the reaction chamber into two non-communication first spaces and second spaces. The product outlet 12 is opened on the chamber wall of the second space. The product discharge part of the reaction tube is located in the second space. The raw material inlet 6 and the raw material outlet 7 are opened on the chamber wall of the first space and are located at both ends of the first space. The vacuum pump is connected to the product discharge part of each reaction tube 11 through the product outlet 12.

[0048] Axially, multiple partition plates 10 are arranged in the reaction chamber at staggered intervals, and the reaction tube 11 passes through the partition plate 10.

[0049] Each reaction tube 11 includes a support layer 14 and a catalyst layer 13 from the inside to the outside. Among them, the support layer 14 forms a single-channel product flow channel 15 around the defined cavity shape. One end of the product flow channel 15 is closed, and the end face of the other end is opened to form a product discharge part.

[0050] The porosity of the support layer 14 is 33%, the pore diameter is 60 nm, the material is alumina, the thickness of the catalyst in the catalyst layer 13 is 60 μm, and the particle diameter is 3000 nm.

[0051] The number N of the reaction tubes is an integer of the diameter of the reactor 4 divided by the diameter of the reaction tube 11. The proportion of the length of the partition plate 10 in the radial direction of the reactor 4 to the diameter of the reactor 4 is 1:3. The number of the partition plates 10 is an integer of the ratio of the length to the diameter of the reactor 4.

[0052] Feed gaseous methanol to the raw material inlet 6. The reaction conditions include: the pressure in the reactor 4 is 0.2 MPa in gauge pressure, the average temperature is 450°C, the temperature difference <5°C, and the material linear velocity in the reactor 4 is 5 m / s. Control the vacuum degree of the product outlet 12 of the reactor 4 to be 2000 Pa, and the catalyst is SAPO-34.

[0053] Result: The methanol conversion rate is 99.995%, and the total yield (by mass) of ethylene and propylene is 84.8%.

[0054] Example 2

[0055] Different from Example 1, the porosity of the support layer 14 is 20%, the pore diameter is 20 nm, and the material is aluminum trioxide.

[0056] The thickness of the catalyst in the catalyst layer 13 is 20 μm, and the particle diameter is 100 nm.

[0057] The number N of the reaction tubes is the diameter of the reactor 4 / the diameter of the reaction tube 11. The proportion of the length of the partition plate 10 in the radial direction of the reactor 4 to the diameter of the reactor 4 is 1:2, and the number of the partition plates 10 is an integer of the ratio of the length to the diameter of the reactor 4.

[0058] The reaction conditions include: the pressure in the reactor 4 is 0.1 MPa in gauge pressure, the average temperature is 360 °C, the temperature difference < 5 °C, and the linear velocity of the material in the reactor 4 is 3 m / s. Control the vacuum degree of the product outlet 12 of the reactor 4 to be 1000 Pa.

[0059] Result: The methanol conversion rate is 99.985%, and the total yield of ethylene and propylene (by mass) is 83.58%.

[0060] Example 3

[0061] Different from Example 1, this MTO device includes 2 reactors 4 connected in series. The porosity of the support layer 14 is 45%, the pore diameter is 100 nm, and the material is aluminum trioxide.

[0062] The thickness of the catalyst in the catalyst layer 13 is 100 μm, and the particle diameter is 5000 nm.

[0063] The number N of the reaction tubes is 0.8 * the diameter of the reactor 4 / the diameter of the reaction tube 11. The proportion of the length of the partition plate 10 in the radial direction of the reactor 4 to the diameter of the reactor 4 is 1:5, and the number of the partition plates 10 is an integer of the ratio of the length to the diameter of the reactor 4.

[0064] The reaction conditions include: the pressure in the reactor 4 is 0.3 MPa in gauge pressure, the average temperature is 500 °C, the temperature difference < 5 °C, and the linear velocity of the material in the reactor 4 is 10 m / s. Control the vacuum degree of the product outlet 12 of the reactor 4 to be 4000 Pa.

[0065] Result: The methanol conversion rate is 99.981%, and the total yield of ethylene and propylene (by mass) is 83.14%.

[0066] Example 4

[0067] Different from Example 1, the porosity of the support layer 14 is 15%, the pore diameter is 150 nm, and the material is aluminum trioxide.

[0068] Result: Methanol conversion rate is 99.945%, and the total yield of ethylene and propylene (by mass) is 81.71%.

[0069] Example 5

[0070] Different from Example 1, the thickness of the catalyst in catalyst layer 13 is 150 μm, and the particle diameter is 6000 nm.

[0071] Result: Methanol conversion rate is 99.93%, and the total yield of ethylene and propylene (by mass) is 81.01%.

[0072] Example 6

[0073] Different from Example 1, the number N of reaction tubes 11 is 0.5 * (diameter of reactor 4 / diameter of reaction tube 11).

[0074] Result: Methanol conversion rate is 99.89%, and the total yield of ethylene and propylene (by mass) is 80.91%.

[0075] Example 7

[0076] Different from Example 1, partition plate 10 is not provided in the reaction chamber.

[0077] Result: Methanol conversion rate is 99.78%, and the total yield of ethylene and propylene (by mass) is 80.56%.

[0078] Example 8

[0079] Different from Example 1, the number N of reaction tubes satisfies N ≤ 0.8 * (diameter of reactor 4 / diameter of reaction tube 11), and the ratio of the length of partition plate 10 in the radial direction of reactor 4 to the diameter of reactor 4 is 1:10.

[0080] Result: Methanol conversion rate is 99.15%, and the total yield of ethylene and propylene (by mass) is 80.22%.

[0081] Example 9

[0082] Different from Example 1, the average temperature is 325 °C.

[0083] Result: Methanol conversion rate is 98.89%, and the total yield of ethylene and propylene (by mass) is 77.25%.

[0084] Example 10

[0085] Different from Example 1, the vacuum degree of product outlet 12 of reactor 4 is controlled at 100 Pa.

[0086] Result: Methanol conversion rate is 98.69%, and the total yield of ethylene and propylene (by mass) is 77.02%.

[0087] Example 11

[0088] Different from Example 1, only one reactor is set up.

[0089] Result: The methanol conversion rate is 96.89%, and the total yield of ethylene and propylene (by mass) is 73.02%.

[0090] Comparative Example 1

[0091] The reactor disclosed in CN102294205A is used to prepare light olefins, and the reaction raw materials and reaction conditions are the same as those in Example 1.

[0092] Result: The methanol conversion rate is 99.971%, and the total yield of ethylene and propylene (by mass) is 82.64%.

[0093] Comparative Example 2

[0094] Different from Example 1, the system and method disclosed in CN 115869861 A are used to prepare light olefins, and the reaction raw materials and reaction conditions are the same as those in Example 1.

[0095] Result: The methanol conversion rate is 98.971%, and the total yield of ethylene and propylene (by mass) is 81.57%.

[0096] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any suitable combination of each specific technical feature. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. But these simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. An MTO device, characterized in that, the MTO device includes a reactor (4), and N (N≥1) reaction tubes (11) are arranged in the reaction chamber of the reactor (4). The reaction tube (11) includes a support layer (14), and a product flow channel (15) is formed around the cavity defined by the support layer (14). A catalyst layer (13) is arranged outside the support layer (14). The raw material inlet (6) of the reactor (4) communicates with the reaction chamber, and the product flow channel (15) of each reaction tube (11) is connected to the discharge part of the reactor (4); wherein, methanol fed through the raw material inlet (6) contacts the catalyst layer (13), and the reaction product passes through the support layer (14) and enters the product flow channel (15).

2. The MTO device according to claim 1, characterized in that, the porosity of the support layer (14) is 20-45%; and / or the pore diameter in the support layer (14) is 20-100 nm; and / or the material of the support layer (14) includes at least one of aluminum oxide, silicon carbide or stainless steel sintered film.

3. The MTO device according to claim 1 or 2, characterized in that, the thickness of the catalyst in the catalyst layer (13) is 20-100 μm; and / or the particle diameter in the catalyst layer (13) is 50-5000 nm.

4. The MTO device according to any one of claims 1-3, characterized in that, the axis of the reaction tube (11) is arranged parallel to the axis of the reaction chamber, and the N reaction tubes (11) are arranged at intervals; preferably N≥0.8*(diameter of the reactor (4) / diameter of the reaction tube (11)).

5. The MTO device according to any one of claims 1-4, characterized in that, along the axial direction, a plurality of partition plates (10) are alternately arranged at intervals in the reaction chamber, and the reaction tubes (11) penetrate through the partition plates (10); preferably, the ratio of the length of the partition plate (10) in the radial direction of the reactor (4) to the diameter of the reactor (4) is 1:1-5; and / or preferably, the number of the partition plates (10) is an integer of the ratio of the length to the diameter of the reactor (4).

6. The MTO device according to any one of claims 1-5, characterized in that, the raw material inlet (6) and the raw material outlet (7) are arranged on the wall of the reactor (4). Among them, the raw material inlet (6) is located at one end far from the product discharge part of the reaction tube (11), and the raw material outlet (7) is located at one end close to the product discharge part of the reaction tube (11); and / or at least two reactors (4) are arranged in the MTO device, and the reactors (4) are connected in series or in parallel.

7. The MTO device according to any one of claims 1-6, characterized in that, the MTO device includes a pressure regulator (5), and the product discharge part of each reaction tube (11) is connected to the pressure regulator (5); the pressure regulator (5) includes a vacuum pump and / or a draft fan.

8. A method for producing light olefins from methanol, characterized in that, the method uses the MTO device described in any one of claims 1-7, including feeding methanol into the reaction chamber of the reactor (4) through the raw material inlet (6), contacting the methanol with the catalyst on the reaction tube (11) to obtain light olefins, and enabling the light olefins to enter the product flow channel (15) and be discharged from the reactor through the pressure difference inside and outside the reaction tube (11).

9. The method according to claim 8, wherein, the reaction conditions include: the pressure in the reactor (4) is 0 to 0.3 MPa in gauge pressure, the average temperature is 350 to 560 °C, the temperature difference < 5 °C, and the material linear velocity in the reactor (4) is 1-10 m / s; and / or controlling the vacuum degree at the product outlet (12) of the reactor (4) to be 500-4000 Pa.

10. The method according to claim 8 or 9, wherein, the catalyst includes at least one of SAPO-34, SAPO-44, SAPO-47 or ZSM-5; and / or when the catalyst activity decreases, replace methanol with regeneration gas to regenerate the catalyst.

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