Reaction apparatus and methods for preparing low-carbon olefins and their applications

Abstract

This invention relates to the field of low-carbon olefin preparation, and discloses a reaction apparatus and a method for preparing low-carbon olefins, as well as their applications. The apparatus includes: at least one fast bed reactor, a descending bed, a mixing zone, a pre-regeneration inclined tube, and a regeneration inclined tube. The outlet of each fast bed reactor is independently connected to the mixing zone. Along the axial direction of the fast bed reactor, each fast bed reactor independently contains m internal components, where m ≥ 1. The porosity of each internal component is independently 80-98%. The mixing zone is connected to the descending bed and the pre-regeneration inclined tube, respectively, for mixing and gas-solid separation. A portion of the pre-regeneration catalyst obtained from gas-solid separation is sent out of the reaction apparatus through the pre-regeneration inclined tube for regeneration. The regeneration inclined tube is connected to the regeneration catalyst inlet of the mixing zone, for sending the regenerated catalyst into the mixing zone to mix with the remaining pre-regeneration catalyst, and then sending it back to the fast bed reactor through the descending bed. When this apparatus is used for the preparation of low-carbon olefins, the yields of ethylene and propylene are high.

Description

Technical Field

[0001] This invention relates to the field of low-carbon olefin preparation, specifically to a reaction apparatus and a method for preparing low-carbon olefins and their applications. 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. Technologies for converting raw materials to produce ethylene and propylene are receiving increasing attention. 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, which can be produced from coal or natural gas, has a very mature process and can achieve a production scale of millions of tons. Therefore, in recent years, the methanol-to-olefins (MTO) process has seen significant development, with three technologies already in industrial application and numerous related patents.

[0003] CN102464534A and CN102372538A disclose a partitioned method for methanol conversion to low-carbon olefins, in which methanol enters a lower premixing zone or catalyst mixing tube and an upper main reaction zone for reaction. In the method disclosed in CN102276398A, liquid methanol enters an initial contact zone and exchanges heat with the catalyst before rising to the main reaction zone to react and produce ethylene and propylene. In the prior art, because the reaction conditions in the premixing zone, catalyst mixing tube, and initial contact zone are unsuitable for methanol conversion, it is difficult to simultaneously achieve high gas velocity and high catalyst density, resulting in carbon-based methanol loss and low diene selectivity. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of difficulty in balancing high gas velocity and high catalyst density and low diene selectivity in the preparation of low-carbon olefins in the prior art, and to provide a reaction apparatus and a method for preparing low-carbon olefins and their applications. When using this reaction apparatus to prepare low-carbon olefins, the selectivity of ethylene and propylene is high.

[0005] To achieve the above objectives, the first aspect of the present invention provides a reaction apparatus comprising: at least one fast bed reactor 1, a descending bed 2, a mixing zone 3, a pre-regeneration inclined tube 7, and a regeneration inclined tube 10;

[0006] in,

[0007] Each fast bed reactor 1 has its outlet independently connected to the mixing zone 3, and the reaction stream containing the catalyst is fed into the mixing zone 3. Along the axial direction of the fast bed reactor 1, each fast bed reactor 1 is independently provided with m internal components 16, where m≥1; the porosity of each internal component 16 is independently 80-98%.

[0008] The mixing zone 3 is connected to the descending bed 2 and the waiting inclined tube 7 respectively, and is used for mixing and gas-solid separation. Part of the waiting catalyst obtained from gas-solid separation is sent out of the reaction device through the waiting inclined tube 7 for regeneration. The regeneration inclined tube 10 is connected to the regeneration catalyst inlet of the mixing zone 3, and is used to send the regeneration catalyst into the mixing zone 3 to mix with the remaining part of the waiting catalyst, and then send it into the fast bed reactor 1 through the descending bed 2.

[0009] A second aspect of the present invention provides a method for preparing low-carbon olefins, wherein the preparation method is carried out in the reaction apparatus described in the first aspect, and includes the following steps:

[0010] S1. The reaction raw material containing methanol is reacted with the catalyst in a fast bed reactor 1 to obtain a mixture including the catalyst and the reaction product;

[0011] S2. The mixture, stripping medium and regenerated catalyst are mixed and separated in mixing zone 3 to obtain reaction products and catalyst to be generated;

[0012] S3. A portion of the unregenerated catalyst is sent out of the reaction device through the unregenerated inclined tube 7 for regeneration, to obtain a regenerated catalyst;

[0013] S4. The regenerated catalyst is fed into the mixing zone 3 through the regeneration inclined tube 10, mixed with the remaining catalyst to be generated, and then fed into the fast bed reactor 1 through the descending bed 2.

[0014] The third aspect of this invention provides the application of the reaction apparatus described in the first aspect or the method for preparing low-carbon olefins described in the second aspect in the preparation of low-carbon olefins.

[0015] The reaction apparatus provided by this invention achieves high catalyst density and linear velocity in the fast bed reactor through the synergistic effect of internal components in the descending bed and fast bed reactors. Simultaneously, by directly returning the regenerated catalyst to the mixing zone, it helps ensure uniform catalyst activity within the fast bed reactor, thereby improving the methanol reaction efficiency. When used for the preparation of low-carbon olefins, this apparatus exhibits high selectivity for ethylene and propylene. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the reaction device in one embodiment of the present invention;

[0017] Figure 2This is a cross-sectional schematic diagram of the connection structure of the mixing zone, the pre-generation inclined tube, and the regeneration inclined tube in this invention.

[0018] Explanation of reference numerals in the attached figures

[0019] 1. Rapid bed reactor 2. Downward flowing bed reactor 3. Mixing zone

[0020] 4. Conveying area; 5. Gas-solid rapid separation equipment; 6. Cyclone separator

[0021] 7. Preparing inclined tube; 8. Heat exchanger; 9. Circulating inclined tube.

[0022] 10 Regeneration inclined tube 11 Reaction feedstock 12 Stripping medium

[0023] 13 Regenerated catalyst 14 Catalyst awaiting regeneration 15 Reaction products

[0024] 16 Internal components 17 Transition zone 18 Rapid fluidization reaction zone Detailed Implementation

[0025] 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.

[0026] In the description of this invention, it should be understood that the terms "length," "upper," "lower," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0027] In this invention, "catalyst awaiting production" refers to the catalyst after it has reacted with the reactants; "regenerated catalyst" refers to the catalyst after it has been regenerated.

[0028] The first aspect of the present invention provides a reaction apparatus comprising: at least one fast bed reactor 1, a descending bed 2, a mixing zone 3, a pre-regeneration inclined tube 7, and a regeneration inclined tube 10;

[0029] in,

[0030] Each fast bed reactor 1 has its outlet independently connected to the mixing zone 3, and the reaction stream containing the catalyst is fed into the mixing zone 3. Along the axial direction of the fast bed reactor 1, each fast bed reactor 1 is independently provided with m internal components 16, where m≥1; the porosity of each internal component 16 is independently 80-98%.

[0031] The mixing zone 3 is connected to the descending bed 2 and the waiting inclined tube 7 respectively, and is used for mixing and gas-solid separation. Part of the waiting catalyst obtained from gas-solid separation is sent out of the reaction device through the waiting inclined tube 7 for regeneration. The regeneration inclined tube 10 is connected to the regeneration catalyst inlet of the mixing zone 3, and is used to send the regeneration catalyst into the mixing zone 3 to mix with the remaining part of the waiting catalyst, and then send it into the fast bed reactor 1 through the descending bed 2.

[0032] According to the present invention, an internal component 16 with a porous structure is provided in the fast bed reactor 1, which helps to increase the catalyst density in the fast bed reactor. The present invention has a wide range of choices for the specific structure and shape of the internal component 16, as long as the porosity requirement mentioned above is met. For example, the internal component 16 can be a porous plate, a grid, or a flow guide baffle.

[0033] According to a specific embodiment of the present invention, the extending direction of the inner member 16 is not parallel to the axial direction of the fast bed reactor 1, so that the catalyst is densified by the inner member 16 when it flows rapidly in the fast bed reactor 1.

[0034] According to the present invention, as long as the extending direction of the internal component 16 is not parallel to the axial direction of the fast bed reactor 1, the extending direction of the internal component 16 can be set at any angle to the axial direction of the fast bed reactor 1. The extending directions of each internal component 16 can be the same or different. To further effectively utilize the function of the internal component 16, preferably, the extending direction of the internal component 16 is perpendicular to the axial direction of the fast bed reactor 1. Adopting the above preferred embodiment is beneficial for maintaining the catalyst density within the fast bed reactor 1 under high linear velocity conditions.

[0035] In this invention, the number of internal components 16 provided in the fast bed reactor 1 is wide-ranging, and can be one or more, preferably three to ten. Those skilled in the art can choose according to actual needs, as long as it is conducive to achieving a high catalyst density and linear velocity in the fast bed reactor.

[0036] In this invention, there are no particular restrictions on the arrangement of the internal components 16 in the rapid bed reactor 1. Preferably, two or more internal components 16 are arranged vertically along the axial direction of the rapid bed reactor 1.

[0037] In this invention, the spacing between adjacent internal components 16 in three or more of the above internal components 16 can be the same or different. This is as long as it facilitates achieving a high catalyst density and linear velocity within the fast bed reactor. According to a preferred embodiment of the invention, the spacing between adjacent internal components 16 decreases sequentially from bottom to top along the axial direction of the fast bed reactor 1, with a reduction in spacing of 5-80%, preferably 10-60%. In this invention, the shortest distance between the extended surfaces of adjacent internal components 16 is denoted as the spacing between adjacent internal components. The percentage of the difference between the upper spacing and the lower spacing in any two spacings formed by three adjacent internal components 16 is denoted as the reduction in spacing.

[0038] In this invention, preferably, the porosity of each internal component 16 is independently 80-95%, more preferably 85-95%. The porosity of each internal component 16 may be the same or different; preferably, the porosity of each internal component 16 is different. In a further preferred embodiment, along the axial direction of the fast bed reactor 1 from bottom to top, the porosity of adjacent internal components 16 decreases sequentially, and the reduction in porosity is preferably 0.1-18%. Under the above preferred embodiments, it is beneficial to achieve uniform radial density within the fast bed reactor.

[0039] In existing technologies, both regenerated and fresh catalysts typically enter the reactor through the bottom of the fast bed reactor. However, the inventors of this invention have creatively proposed a method where the regenerated catalyst is directly fed into the mixing zone 3 by connecting the regeneration inclined tube 10 to the mixing zone 3, where it mixes with the remaining catalyst to be generated. This implementation method facilitates uniform mixing of the catalyst and the catalyst to be generated within the mixing zone 3, meeting the activity and temperature requirements for the high selective conversion of methanol to ethylene and propylene. It also helps ensure uniform catalyst activity within the fast bed reactor, reduces methanol carbon deposition losses, and improves the overall yield of ethylene and propylene.

[0040] To ensure thorough mixing of the regenerated catalyst in mixing zone 3, the angle θ between the longitudinal section of the regenerated inclined tube 10 and the longitudinal section of the unregenerated inclined tube 7 is preferably 90-180°, and more preferably 100-180°. A cross-sectional schematic diagram of the connection structure between the mixing zone, the unregenerated inclined tube, and the regenerated inclined tube is shown below. Figure 2 As shown, under the above-described preferred embodiments, it is beneficial to further improve the reaction effect.

[0041] The present invention allows for a wide range of choices regarding the number of rapid bed reactors; the reaction apparatus can include two or more rapid bed reactors. Preferably, the number of rapid bed reactors 1 is 2-10. Two or more rapid bed reactors are connected in parallel, each independently connected to the mixing zone 3 and the descending bed 2.

[0042] In a further preferred embodiment, two or more fast bed reactors 1 are circumferentially distributed around the axial direction of the mixing zone 3. This preferred embodiment facilitates achieving high linear velocity and high-density reaction conditions within the fast bed reactors. The number of internal components 16 in each fast bed reactor can be the same or different, but is preferably the same, which is more conducive to ensuring product consistency.

[0043] According to a specific embodiment of the present invention, along the axial direction from bottom to top of the rapid bed reactor 1, the rapid bed reactor 1 includes a rapid fluidization reaction zone 18, a transition zone 17, a conveying zone 4, and a gas-solid rapid separation device 5. The rapid fluidization reaction zone 18 is provided with a catalyst inlet, and the catalyst to be generated from the descending bed (2) is fed into the rapid fluidization reaction zone 18, so that the catalyst to be generated 14 passes through the transition zone 17, the conveying zone 4, and the gas-solid rapid separation device 5 in sequence; wherein, the internal component 16 is provided in the rapid fluidization reaction zone 18.

[0044] Preferably, the gas-solid rapid separation device 5 and at least part of the conveying zone 4 are located inside the mixing zone 3 for the initial separation of reaction products and the catalyst to be generated.

[0045] According to a preferred embodiment of the present invention, the height ratio of the rapid fluidization reaction zone 18, the transition zone 17, and the transport zone 4 is 1:(0.08-0.2):(0.5-3), preferably 1:(0.1-0.18):(0.55-2.5). This preferred embodiment facilitates the effective suppression of secondary reactions of the product gas by increasing the product gas linear velocity and enhancing the separation of the product gas and the catalyst.

[0046] According to a preferred embodiment of the present invention, the ratio of the inner diameter of the rapid fluidization reaction zone 18 to the inner diameter of the transport zone 4 is (1.2-3):1, preferably (1.3-2.2):1.

[0047] In this invention, to fully utilize the function of the internal component 16, preferably, the connection point between the internal component 16 and the rapid fluidization reaction zone 18 is higher than the catalyst inlet of the rapid fluidization reaction zone 18. It is understood that when only one internal component 16 is provided, its connection point with the rapid fluidization reaction zone 18 is higher than the catalyst inlet of the rapid fluidization reaction zone 18; when two or more internal components 16 are provided, the connection point between the lowest internal component 16 and the rapid fluidization reaction zone 18 is higher than the catalyst inlet of the rapid fluidization reaction zone 18.

[0048] According to a preferred embodiment of the present invention, the ratio of the distance from the catalyst inlet to the bottom of the fast bed reactor 1 in the fast fluidized bed reaction zone 18 to the total height of the fast fluidized bed reaction zone 18 is (0.01-0.3):1, preferably (0.05-0.25):1. Under this preferred embodiment, it is beneficial for methanol to contact the catalyst more fully within the fast bed reactor, while ensuring uniform gas-solid contact.

[0049] In a further preferred embodiment, the ratio of the distance between the lowest inner component 16 and the bottom of the fast bed reactor 1 to the total height of the rapid fluidization reaction zone 18 along the axial direction of the fast bed reactor 1 from bottom to top is 0.05-0.6:1, preferably 0.1-0.5:1.

[0050] In a further preferred embodiment, the ratio of the distance between the uppermost inner component 16 and the bottom of the fast reactor 1 to the total height of the fast fluidized reaction zone 18 along the axial direction of the fast bed reactor 1 from bottom to top is 0.6-0.9:1, preferably 0.6-0.8:1.

[0051] Preferably, the bottom of the fast bed reactor 1 is provided with a reaction raw material inlet 11, which is not higher than the catalyst inlet of the fast fluidized bed reaction zone 18.

[0052] According to a specific embodiment of the present invention, at least one circulating inclined tube 9 is provided at the bottom of the descending bed 2, which is respectively connected to the catalyst inlet of the rapid fluidization reaction zone 18 of each descending bed 2. The circulating inclined tube is used to feed the catalyst into each descending bed 2 respectively, and the number of circulating inclined tubes is not less than the number of descending beds. Preferably, the number of circulating inclined tubes is the same as the number of descending beds.

[0053] In one specific embodiment, a catalyst flow controller 21 is provided on the upper part of the descending bed 2 to control the flow rate of the catalyst entering the descending bed.

[0054] In one specific embodiment, the mixing zone 3 is equipped with a cyclone separator 6 and an optional heat exchanger 8. The cyclone separator 6 is used to separate the reaction stream containing the catalyst to be generated into a gas-solid mixture. The heat exchanger is used to maintain the reaction temperature of the fast bed reactor, and the heat load is controlled by the actual temperature of the fast bed reactor.

[0055] A second aspect of the present invention provides a method for preparing low-carbon olefins, wherein the preparation method is carried out in the reaction apparatus described in the first aspect, and includes the following steps:

[0056] S1. The reaction raw material containing methanol is reacted with the catalyst in a fast bed reactor 1 to obtain a mixture including the catalyst to be generated and the reaction product;

[0057] S2. The mixture and stripping medium are mixed and separated in mixing zone 3 to obtain reaction products and catalyst to be generated;

[0058] S3. A portion of the unregenerated catalyst is sent out of the reaction device through the unregenerated inclined tube 7 for regeneration, to obtain a regenerated catalyst;

[0059] S4. The regenerated catalyst is fed into the mixing zone 3 through the regeneration inclined tube 10, mixed with the remaining catalyst to be generated, and then fed into the fast bed reactor 1 through the descending bed 2.

[0060] In this invention, a catalyst cycle is established between the mixing zone and the fast bed reactor through a fast bed reactor, a mixing zone, and a descending bed connected in sequence. The regenerated catalyst and the catalyst to be generated are fully mixed in the mixing zone to provide a catalyst with suitable activity and temperature for the fast bed reactor. By setting internal components in the fast bed reactor, a high catalyst density and linear velocity are achieved in the fast bed reactor. When this device is used for the preparation of low-carbon olefins, ethylene and propylene have high selectivity.

[0061] It is understandable that when the reaction is initially initiated, the catalyst in step S1 is a fresh catalyst (a catalyst with suitable activity and temperature). When the reaction is running continuously, since some of the spent catalyst is returned to the fast bed reactor 1, the catalysts participating in the reaction include the regenerated catalyst and some spent catalyst.

[0062] According to the present invention, preferably, in step S1, the contact conditions include: a reaction temperature of 430-550°C, a reaction pressure of 0.01-0.5 MPa (gauge pressure), a gas phase linear velocity of 1.5-3 m / s, and a catalyst density of 100-300 kg / m³. 3 Preferably, the reaction temperature is 440-520℃, the reaction pressure is 0.05-0.4MPa (gauge pressure), the gas phase linear velocity is 1.5-2.5m / s, and the catalyst density is 120-250kg / m³. 3 .

[0063] In existing technologies, when the gas phase linear velocity is 1.5-3 m / s, the catalyst density is generally only 20-60 kg / m³. 3 In such cases, the product yield is unsatisfactory. However, the reaction apparatus provided by this invention can achieve both high gas phase linear velocity and catalyst density.

[0064] According to a specific embodiment of the present invention, in step S3, the mass ratio of the catalyst to be generated in the descending bed 2 to the catalyst to be generated in the inclined tube 7 is (10-60):1, preferably (20-50):1. Under the above preferred embodiment, it is beneficial to obtain suitable catalyst activity for the methanol conversion reaction.

[0065] According to a specific embodiment of the present invention, in step S3, the regeneration includes: coking regeneration of a portion of the spent catalyst in the presence of a regeneration medium. The present invention does not particularly limit the specific operating conditions for the coking regeneration; conventional methods in the art can be used, as long as the regeneration of the spent catalyst can be achieved. Preferably, based on the total mass of the regenerated catalyst, the carbon content in the regenerated catalyst is 0.01-3.5 wt%, more preferably 0.5-2.5 wt%. In the prior art, to ensure the reactivity of the catalyst, a very low carbon content is usually required in the regenerated catalyst. However, in the present invention, since a portion of the spent catalyst and the regenerated catalyst are thoroughly mixed in the mixing zone and then refluxed to the downward flowing bed 2, the uniformity of catalyst activity in the fast bed reactor can be improved. Controlling the carbon content of the regenerated catalyst within the above-mentioned preferred range helps to reduce methanol carbon deposition consumption and improve the MTO reaction effect.

[0066] According to a specific embodiment of the present invention, the conditions for coke regeneration include: a regeneration temperature of 550-700℃, an oxygen volume percentage of 5-40% in the regeneration medium, and a linear velocity of 0.3-1.2 m / s in the regeneration medium.

[0067] In this invention, a wide range of catalysts can be selected, and any conventional catalysts in the art capable of producing low-carbon olefins from methanol can be used. Preferably, the catalyst is a SAPO-34 molecular sieve catalyst. Using the above-mentioned preferred catalyst can further improve the yield of low-carbon olefins. The SAPO-34 molecular sieve catalyst can be commercially available or prepared using conventional methods in the art, and this invention does not have any particular limitations on this.

[0068] According to the present invention, the reaction raw material containing methanol can be methanol or a mixture containing methanol, such as water, dimethyl ether, ethanol, acetaldehyde, acetone, butanone, etc.; the selection range of methanol content in the reaction raw material is relatively wide. In order to further improve the effect of methanol catalytic conversion, preferably, the methanol content in the reaction raw material is 30-100 wt%.

[0069] In this invention, the selection of the stripping medium is relatively broad. Preferably, the stripping medium is selected from at least one of steam, nitrogen, and by-product oxygenated compound feedstock. The by-product oxygenated compound feedstock can be derived from oxygenated compounds produced during the preparation of low-carbon olefins, including water and oxygenated compounds. These oxygenated compounds include alcohols, aldehydes, and ketones, such as methanol and at least one of ethanol, propanol, butanol, acetaldehyde, propionaldehyde, butyraldehyde, acetone, butanone, formic acid, acetic acid, and propionic acid. Preferably, the mass percentage of oxygenated compounds in the by-product oxygenated compound feedstock is 5-80%, and based on the total mass of oxygenated compounds, the mass percentage of aldehydes and ketones is 30-60%, and the mass percentage of methanol is 40-70%.

[0070] According to a specific embodiment of the present invention, the preparation of the low-carbon olefin is carried out in a low-carbon olefin reaction apparatus, such as... Figure 1 As shown, the methanol-containing reactant 11 and the catalyst are reacted in the rapid fluidized bed reaction zone 18 of the rapid bed reactor 1. The catalyst is densified by at least one internal component 16 in the rapid bed reactor 1 to obtain a mixture including the unregenerated catalyst and the reaction product. The porosity of the internal component 16 is 90-98%. The mixture flows from bottom to top along the axial direction of the rapid bed reactor 1 through the transition zone 17, the conveying zone 4, and the gas-solid rapid separation device 5. Then, the mixture is mixed with the stripping medium 12 in the mixing zone 3 and separated by the cyclone separator 6. The resulting reaction product 15 is sent to the reaction device. The separated portion of the unregenerated catalyst 14 is sent out of the reaction device through the unregenerated inclined tube 7 and then regenerated by coking to obtain the regenerated catalyst 13. The regenerated catalyst 13 is sent to the mixing zone 3 through the regeneration inclined tube 10 and mixed with the remaining portion of the unregenerated catalyst 14 and sent to the descending bed 2. It is then returned to the rapid bed reactor 1 through the circulating inclined tube 9.

[0071] The third aspect of this invention provides the application of the reaction apparatus described in the first aspect or the method for preparing low-carbon olefins described in the second aspect in the preparation of low-carbon olefins.

[0072] The present invention will be described in detail below through embodiments.

[0073] Example 1

[0074] The reaction apparatus used is as follows Figure 1As shown, the device includes: three rapid bed reactors 1, a mixing zone 3, and a descending bed 2; a cyclone separator 6 is installed in the mixing zone 3. Two circulating inclined tubes 9 are installed at the bottom of the descending bed 2, which are connected to the catalyst inlet of the rapid bed reactors 1 via the circulating inclined tubes 9. A catalyst flow controller 21 is installed at the top of the descending bed 2. The outlet of the catalyst to be generated in the mixing zone 3 is connected to the catalyst to be generated inclined tube 7. The heat exchanger 8 is an internal heat exchanger installed inside the mixing zone 3. The inlet of the regenerated catalyst in the mixing zone 3 is connected to the regeneration inclined tube 10. The angle θ between the longitudinal section of the regeneration inclined tube 10 and the longitudinal section of the catalyst to be generated inclined tube 7 is 150°.

[0075] Along the axial direction of each rapid bed reactor 1 from bottom to top, the rapid bed reactor 1 includes a rapid fluidization reaction zone 18, a transition zone 17, a conveying zone 4, and a gas-solid rapid separation device 5. The height ratio of the rapid fluidization reaction zone 18, the transition zone 17, and the conveying zone 4 is 1:0.12:1.5, and the diameter ratio of the rapid fluidization reaction zone 18 to the diameter of the conveying zone 4 is 2:1.

[0076] The rapid fluidized bed reaction zone 18 is provided with a catalyst inlet connected to the circulating inclined tube 9. The ratio of the distance from the catalyst inlet in the rapid fluidized bed reaction zone 18 to the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.15:1. Along the axial direction of the rapid bed reactor 1, the rapid fluidized bed reaction zone 18 is provided with 4 internal components 16. The extension direction of the internal components 16 is perpendicular to the axial direction of the rapid bed reactor 1. The ratio of the distance between the bottommost internal component 16 and the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.2:1; the ratio of the distance between the topmost internal component 16 and the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.7:1. The distances between the 4 internal components 16 are not the same, and the spacing between adjacent internal components (16) decreases by 30%. The 4 internal components 16 are all porous plates, and the porosities of the internal components 16 from bottom to top are 93%, 90%, 90%, and 87%, respectively.

[0077] The preparation of low-carbon olefins is carried out in the above-mentioned reaction apparatus.

[0078] 100 wt% methanol and SAPO-34 molecular sieve catalyst (commercially purchased, brand: SMTO-II) are reacted in the rapid fluidized bed reaction zone 18 of the fast bed reactor 1 to obtain a mixture including catalyst and reaction products. The catalyst is densified by internal components 16 in the fast bed reactor 1. The mixture flows from bottom to top along the axial direction of the fast bed reactor 1 through the transition zone 17, the conveying zone 4, and the gas-solid rapid separation device 5. The mixture is mixed with steam and by-product oxygen-containing raw materials in the mixing zone 3 and separated by a cyclone separator 6 to obtain the reaction products and the catalyst to be recycled. A portion of the catalyst to be recycled is sent out of the reaction device through the recycled inclined tube 7 and then regenerated by coking at 630°C, with an oxygen volume percentage of 21% in the regeneration medium and a linear velocity of 0.7 m / s in the regeneration medium to obtain a regenerated catalyst with a carbon content of 2.0 wt%. The regenerated catalyst is fed into the mixing zone 3 through the regeneration inclined tube 10, where it is mixed with the remaining unregenerated catalyst and fed into the descending bed 2. It is then returned to the fast bed reactor 1 through the circulating inclined tube 9 to react with the reactants. The mass ratio of the unregenerated catalyst fed into the descending bed 2 to the unregenerated catalyst fed into the unregenerated inclined tube 7 is 30:1.

[0079] The by-product oxygenated compound feedstock includes oxygenated compounds and water; based on the mass of water as 100%, the mass content of oxygenated compounds is 35%, and the mass content of water is 65%; the oxygenated compounds include alcohols, aldehydes, and ketones; based on the mass of oxygenated compounds as 100%, the mass content of ketones is 40%, the mass content of aldehydes is 10%, and the remainder is alcohols. The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low-carbon olefins is calculated.

[0080] The total yield of low-carbon olefins refers to the total yield of ethylene and propylene.

[0081] Total yield of low-carbon olefins (%) = Total mass of ethylene and propylene in the product / Mass of methanol carbon-based product × 100%;

[0082] The mass of methanol carbon-based methanol = the mass of methanol × 14 / 32.

[0083] Example 2

[0084] The reaction apparatus used and Figure 1Similarly, the device includes: five fast bed reactors 1, a mixing zone 3, and a descending bed 2, with each fast bed reactor evenly distributed circumferentially around the axis of the mixing zone 3. A cyclone separator 6 is installed in the mixing zone 3. Ten circulating inclined tubes 9 are installed at the bottom of the descending bed 2, and the descending bed 2 is connected to the catalyst inlet of the fast bed reactor 1 via the circulating inclined tubes 9. A catalyst flow controller 21 is installed at the top of the descending bed 2. The outlet of the catalyst to be generated in the mixing zone 3 is connected to the catalyst to be generated inclined tube 7. The heat exchanger 8 is an external heat exchanger, and the mixing zone 3 is connected to the heat exchanger 8. The inlet of the regenerated catalyst in the mixing zone 3 is connected to the regenerated inclined tube 10. The angle θ between the longitudinal section of the regenerated inclined tube 10 and the longitudinal section of the catalyst to be generated inclined tube (7) is 120°.

[0085] Along the axial direction of each rapid bed reactor 1 from bottom to top, the rapid bed reactor 1 includes a rapid fluidization reaction zone 18, a transition zone 17, a conveying zone 4, and a gas-solid rapid separation device 5. The height ratio of the rapid fluidization reaction zone 18, the transition zone 17, and the conveying zone 4 is 1:0.15:2, and the ratio of the diameter of the rapid fluidization reaction zone 18 to the diameter of the conveying zone 4 is 1.5:1.

[0086] The rapid fluidized bed reaction zone 18 is provided with a catalyst inlet connected to the circulating inclined tube 9. The ratio of the distance from the catalyst inlet in the rapid fluidized bed reaction zone 18 to the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.25:1. Along the axial direction of the rapid bed reactor 1, the rapid fluidized bed reaction zone 18 is provided with 6 internal components 16, each extending perpendicular to the axial direction of the rapid bed reactor 1. The ratio of the distance between the bottommost internal component 16 and the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.1:1; the ratio of the distance between the topmost internal component 16 and the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.75:1. The distances between the 6 internal components 16 are not the same, and the spacing between adjacent internal components 16 decreases by 50%. The 6 internal components 16 are grids, each with a porosity of 90%.

[0087] The preparation of low-carbon olefins is carried out in the above-mentioned reaction apparatus.

[0088] Methanol with a content of 80 wt% was reacted with SAPO-34 molecular sieve catalyst (commercially purchased, brand: SMTO-II) in the rapid fluidized bed reaction zone 18 of the rapid bed reactor 1 to obtain a mixture including catalyst and reaction products. The catalyst was densified by internal components 16 in the rapid bed reactor 1. The mixture flowed from bottom to top along the axial direction of the rapid bed reactor 1 through the transition zone 17, the conveying zone 4, and the gas-solid rapid separation device 5. The mixture was mixed with nitrogen and water vapor in the mixing zone 3 and separated by a cyclone separator 6 to obtain the reaction products and the catalyst to be recycled. A portion of the catalyst to be recycled was sent out of the reaction device through the recycled inclined tube 7 and then regenerated by coking at 600°C, with an oxygen volume percentage of 21% in the regeneration medium and a linear velocity of 0.6 m / s in the regeneration medium to obtain the regenerated catalyst with a carbon content of 3.0 wt%. The regenerated catalyst is fed into the mixing zone 3 through the regeneration inclined tube 10, mixed with the remaining catalyst to be generated, and then fed into the descending bed 2. It is then returned to the fast bed reactor 1 through the circulating inclined tube 9 to react with the raw materials. The mass ratio of the catalyst to be generated fed into the descending bed 2 to the catalyst to be generated fed into the inclined tube 7 is 40:1.

[0089] The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low-carbon olefin carbon-based products was calculated.

[0090] Example 3

[0091] The same reaction apparatus as in Example 1 is used, except that eight internal components 16 with different porosities are arranged in the rapid fluidization reaction zone 18 along the axial direction of the rapid bed reactor 1. From bottom to top along the axial direction of the rapid bed reactor, the bottom five internal components 16 are grids, and the top three internal components 16 are perforated plates; the porosities of the internal components 16 from bottom to top are 95%, 93%, 90%, 88%, 88%, 85%, 85%, and 85%, respectively. The distances between the eight internal components 16 are not the same, and the spacing between adjacent internal components (16) decreases by 20%.

[0092] The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low-carbon olefin carbon-based products was calculated.

[0093] Example 4

[0094] The method is the same as in Example 1, except that the mass ratio of the portion of the catalyst to be generated fed into the descending bed 2 to the mass of the catalyst to be generated fed into the inclined tube 7 is 15:1.

[0095] The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low carbon olefins was calculated.

[0096] Example 5

[0097] The method is the same as in Example 1, except that the rapid fluidized bed reaction zone 18 is provided with an inner component 16. The extension direction of the inner component 16 is perpendicular to the axis of the rapid bed reactor 1. The ratio of the distance between the inner component 16 and the bottom of the rapid bed reactor 1 to the total height of the rapid fluidized bed reaction zone 18 is 0.6:1. The inner component 16 is a porous plate with a porosity of 80%.

[0098] The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low carbon olefins was calculated.

[0099] Example 6

[0100] The method is the same as in Example 1, except that the angle θ between the longitudinal section of the regenerated inclined tube 10 and the longitudinal section of the unregenerated inclined tube 7 is 60°.

[0101] The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low carbon olefins was calculated.

[0102] Comparative Example 1

[0103] The method described in Example 1 was used, except that the regeneration inclined tube was connected to the bottom of the fast bed reactor and was at the same height as the catalyst inlet of the fast fluidized bed reaction zone 18. The reaction conditions of the fast bed reactor 1 are shown in Table 1. After 500 hours of continuous reaction, the total yield of low-carbon olefins was calculated.

[0104] Comparative Example 2

[0105] The same reaction apparatus as in Example 1 is used, except that the fast bed reactor 1 does not contain internal components 16.

[0106] The reaction conditions of the fast bed reactor 1 are shown in Table 1. After continuous reaction for 500 h, the total yield of low carbon olefins was calculated.

[0107] Table 1

[0108]

[0109] As can be seen from the results in Table 1, the present invention can achieve a high catalyst density and linear velocity in the fast bed reactor. At the same time, the regenerated catalyst and the catalyst to be generated are mixed in the mixing zone, which helps to ensure the uniformity of catalyst activity in the fast bed reactor and obtain the total yield of high and low carbon olefins.

[0110] The preferred embodiments of the present invention have been described in detail above; 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 technical features in any other suitable manner. 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 reaction apparatus, characterized in that, The device includes: at least one fast bed reactor (1), a descending bed (2), a mixing zone (3), a pre-regeneration inclined tube (7), and a regeneration inclined tube (10); in, Each fast bed reactor (1) has its outlet independently connected to the mixing zone (3), and the reactant stream containing the catalyst to be generated is fed into the mixing zone (3). Along the axial direction of the fast bed reactor (1), each fast bed reactor (1) is independently provided with m internal components (16), where m≥1; the porosity of each internal component (16) is independently 80-98%; the internal component (16) is a porous plate, grid or flow guide baffle; the extension direction of the internal component (16) is not parallel to the axial direction of the fast bed reactor (1); two or more of the internal components (16) are arranged vertically along the axial direction of the fast bed reactor (1); The mixing zone (3) is connected to the descending bed (2) and the regenerating inclined tube (7) respectively, and is used for mixing and gas-solid separation. Part of the regenerating catalyst obtained from gas-solid separation is sent out of the reaction device through the regenerating inclined tube (7) for regeneration. The regeneration inclined tube (10) is connected to the regeneration catalyst inlet of the mixing zone (3), and is used to send the regenerated catalyst into the mixing zone (3) to mix with the remaining part of the regenerating catalyst, and then send it into the fast bed reactor (1) through the descending bed (2).

2. The reaction apparatus according to claim 1, wherein, In three or more of the aforementioned inner components (16), the spacing between adjacent inner components (16) may be the same or different.

3. The reaction apparatus according to claim 2, wherein, Along the axial direction of the fast bed reactor (1) from bottom to top, the spacing between adjacent internal components (16) decreases sequentially, with the reduction in spacing being 5-80%.

4. The reaction apparatus according to claim 1, wherein, The porosity of each internal component (16) is independently 80-95%, and the m is 1-20.

5. The reaction apparatus according to claim 4, wherein, The porosity of each internal component (16) is independently 85-95%; m is 3-10.

6. The reaction apparatus according to claim 5, wherein, The porosity of the m internal components (16) is different, and the porosity of adjacent internal components (16) decreases sequentially from bottom to top along the axial direction of the fast bed reactor (1).

7. The reaction apparatus according to claim 6, wherein, The porosity of the m internal components (16) is different. Along the axial direction of the fast bed reactor (1) from bottom to top, the porosity of adjacent internal components (16) decreases by 0.1-18%.

8. The reaction apparatus according to claim 1, wherein, The angle θ between the longitudinal section of the regenerated inclined tube (10) and the longitudinal section of the ungenerated inclined tube (7) is 90-180°.

9. The reaction apparatus according to claim 8, wherein, The angle θ between the longitudinal section of the regenerated inclined tube (10) and the longitudinal section of the ungenerated inclined tube (7) is 100-180°.

10. The reaction apparatus according to claim 1, wherein, The number of the fast bed reactors (1) is two or more.

11. The reaction apparatus according to claim 10, wherein, The number of the fast bed reactors (1) is 2-10.

12. The reaction apparatus according to claim 10, wherein, Two or more of the fast bed reactors (1) are circumferentially distributed around the axial direction of the mixing zone (3).

13. The reaction apparatus according to claim 1, wherein, Along the axial direction of the fast bed reactor (1) from bottom to top, the fast bed reactor (1) includes a rapid fluidization reaction zone (18), a transition zone (17), a transport zone (4), and a gas-solid rapid separation device (5). The rapid fluidized bed reaction zone (18) is provided with a catalyst inlet connected to the downflow bed (2), and a portion of the catalyst to be generated from the downflow bed (2) is fed into the rapid fluidized bed reaction zone (18), so that the catalyst passes through the transition zone (17), the transport zone (4) and the gas-solid rapid separation device (5) in sequence; wherein, the internal components (16) are provided in the rapid fluidized bed reaction zone (18). The gas-solid rapid separation device (5) and at least part of the conveying zone (4) are located inside the mixing zone (3).

14. The reaction apparatus according to claim 13, wherein, The height ratio of the rapid fluidization reaction zone (18), the transition zone (17), and the transport zone (4) is 1:(0.08-0.2):(0.5-3).

15. The reaction apparatus according to claim 13, wherein, The ratio of the inner diameter of the rapid fluidization reaction zone (18) to the inner diameter of the transport zone (4) is (1.2-3):

1.

16. The reaction apparatus according to claim 13, wherein, The ratio of the distance from the catalyst inlet of the rapid fluidized bed reactor (1) to the bottom of the rapid fluidized bed reactor (1) to the total height of the rapid fluidized bed reactor (18) is (0.01-0.3):

1.

17. The reaction apparatus according to claim 16, wherein, The ratio of the distance from the catalyst inlet of the rapid fluidized bed reactor (1) to the bottom of the rapid fluidized bed reactor (1) to the total height of the rapid fluidized bed reactor (18) is (0.05-0.25):

1.

18. The reaction apparatus according to claim 13, wherein, Along the axial direction of the fast bed reactor (1) from bottom to top, the ratio of the distance between the lowest inner component (16) and the bottom of the fast bed reactor (1) to the total height of the fast fluidized reaction zone (18) is (0.05-0.6):

1.

19. The reaction apparatus according to claim 18, wherein, Along the axial direction of the fast bed reactor (1) from bottom to top, the ratio of the distance between the lowest inner component (16) and the bottom of the fast bed reactor (1) to the total height of the fast fluidized reaction zone (18) is (0.1-0.5):

1.

20. The reaction apparatus according to claim 13, wherein, Along the axial direction of the fast bed reactor (1) from bottom to top, the ratio of the distance between the uppermost inner component (16) and the bottom of the fast reactor (1) to the total height of the fast fluidized reaction zone (18) is (0.6-0.9):

1.

21. The reaction apparatus according to claim 20, wherein, Along the axial direction of the fast bed reactor (1) from bottom to top, the ratio of the distance between the uppermost inner component (16) and the bottom of the fast reactor (1) to the total height of the fast fluidized reaction zone (18) is (0.6-0.8):

1.

22. The reaction apparatus according to claim 1, wherein, The bottom of the downflow bed (2) is provided with at least one circulating inclined tube (9), which is connected to the catalyst inlet of the fast fluidization reaction zone (18) of each downflow bed (2).

23. The reaction apparatus according to claim 1, wherein, A catalyst flow controller (21) is installed on the upper part of the descending bed (2).

24. The reaction apparatus according to claim 1, wherein, The mixing zone (3) is equipped with a cyclone separator (6) and an optional heat exchanger (8).

25. A method for preparing low-carbon olefins, characterized in that, The preparation method is carried out in the reaction apparatus according to any one of claims 1-24, and includes the following steps: S1. The reaction raw material containing methanol is contacted with the catalyst in a fast bed reactor (1) to react and obtain a mixture including the catalyst to be generated and the reaction product; S2. The mixture and stripping medium are mixed in the mixing zone (3), and then the reaction products and the catalyst to be generated are separated. S3. A portion of the catalyst to be regenerated is sent out of the reaction device through the regenerated inclined tube (7) to be regenerated, and a regenerated catalyst is obtained. S4. The regenerated catalyst is fed into the mixing zone (3) through the regeneration inclined tube (10) and mixed with the remaining catalyst to be generated. The mixture is then fed into the fast bed reactor (1) through the descending bed (2).

26. The preparation method according to claim 25, wherein, In step S1, the contact conditions include: a reaction temperature of 430-550℃, a reaction pressure of 0.01-0.5 MPa (gauge pressure), a gas phase linear velocity of 1.5-3 m / s, and a catalyst density of 100-300 kg / m³. 3 .

27. The preparation method according to claim 26, wherein, The reaction temperature is 450-520℃, the reaction pressure is 0.05-0.4 MPa (gauge pressure), the gas phase linear velocity is 1.5-2.5 m / s, and the catalyst density is 120-250 kg / m³. 3 .

28. The preparation method according to any one of claims 25-27, wherein, In step S3, the mass ratio of the catalyst to be generated in the descending bed (2) to the catalyst to be generated in the inclined tube (7) is (10-60):

1.

29. The preparation method according to claim 28, wherein, In step S3, the mass ratio of the catalyst to be generated in the descending bed (2) to the catalyst to be generated in the inclined tube (7) is (20-50):

1.

30. The preparation method according to any one of claims 25-27, wherein, In step S3, the regeneration includes: in the presence of a regeneration medium, performing coking regeneration on a portion of the catalyst to be regenerated.

31. The preparation method according to claim 30, wherein, The carbon content in the regenerated catalyst is 0.01-3.5 wt% based on the total mass of the regenerated catalyst.

32. The preparation method according to claim 31, wherein, The carbon content in the regenerated catalyst is 0.5-2.5 wt% based on the total mass of the regenerated catalyst.

33. The preparation method according to any one of claims 25-27, wherein, The catalyst is a SAPO-34 molecular sieve catalyst.

34. The preparation method according to any one of claims 25-27, wherein, The methanol content in the reaction raw materials is 30-100 wt%.

35. The preparation method according to any one of claims 25-27, wherein, The stripping medium is selected from at least one of steam, nitrogen, and by-product oxygenated compound feedstock.

36. The application of the reaction apparatus according to any one of claims 1-24 or the method for preparing low-carbon olefins according to any one of claims 25-35 in the preparation of low-carbon olefins.

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