A method for rapidly preparing propiolalcohol by using a fluidized bed reactor

Abstract

The application belongs to the field of fine chemical industry, and particularly relates to a method for rapidly preparing propargyl alcohol by using a fluidized bed reactor. 1,4-butynediol is used as raw material to produce propargyl alcohol and formaldehyde through a catalytic cracking reaction in a fluidized bed reactor under the action of a catalyst. After being separated and purified, the product is propargyl alcohol. The deactivated catalyst is regenerated in a catalyst regenerator and then recycled. The cracking reaction process is safe, dangerous gas acetylene is not used, the one-way conversion rate of 1,4-butynediol is greater than or equal to 65%, and the main reaction selectivity in the product is greater than or equal to 85%.

Description

Technical Field

[0001] This invention belongs to the field of fine chemicals, and specifically relates to a method for rapidly preparing propynyl alcohol using a fluidized bed reactor. Background Technology

[0002] Propynol contains both alkynyl and hydroxyl groups, making it an important chemical intermediate widely used in the pharmaceutical, electroplating, and resin industries. It is primarily used to prepare brighteners for nickel plating, rust removers, slow-release agents, and corrosion inhibitors. Propynol exhibits unique properties in inhibiting the corrosion of metals such as iron, copper, and nickel by acidic substances like acetic acid, phosphoric acid, sulfuric acid, and hydrochloric acid. Internationally, it is widely used as an acidification and corrosion inhibitor in oil and gas wells under high temperature, high pressure, and high-concentration hydrochloric acid conditions.

[0003] Currently, the commonly used method for preparing propargyl alcohol is the acetylene-aldehyde process. The Reppe process uses acetylene and formaldehyde as raw materials, and the synthesis is carried out under the catalytic action of copper acetylene as the active component. Under low pressure, due to the low solubility of acetylene gas in formaldehyde aqueous solution, the formaldehyde concentration on the catalyst surface is always much higher than that of acetylene. This makes it very easy for one molecule of acetylene to react with two molecules of formaldehyde to produce 1,4-butynediol, rather than stopping the reaction at the stage of one molecule of acetylene reacting with one molecule of formaldehyde to produce propargyl alcohol. The yield of propargyl alcohol is extremely low or even non-existent. Therefore, the yield of propargyl alcohol, a byproduct in the traditional acetylene-aldehyde process for producing 1,4-butynediol, is extremely low, difficult to separate and purify, and cannot be utilized.

[0004] To improve propargyl alcohol yield, current production processes consider increasing reaction pressure by reacting high-pressure acetylene with a very low concentration of formaldehyde solution to increase the acetylene / formaldehyde ratio and thus improve propargyl alcohol selectivity. However, the propargyl alcohol content in the solution after the reaction is very low; even with increased acetylene partial pressure, the highest propargyl alcohol yield is only 37%. This low yield significantly impacts the economic benefits of enterprises. Furthermore, high-pressure acetylene is dangerous, frequently causing combustion and explosion accidents, severely hindering the healthy development of propargyl alcohol and downstream industries.

[0005] GB1232257A discloses the introduction of tetrahydrofuran and dimethyltetrahydrofuran, which are miscible with formaldehyde solution and are good solvents for acetylene, into the reaction system as a reaction medium to increase the yield of propargyl alcohol by improving the solubility of acetylene. The technical solution disclosed in US2712560A directly uses acetone as the reaction medium, where acetylene dissolves in the liquid reaction solution during the reaction, thereby improving the selectivity and yield of propargyl alcohol. While good solvents for acetylene are beneficial to increasing the yield of propargyl alcohol to some extent, they also increase the difficulty of product purification. The purification process requires handling large amounts of reaction medium, involves numerous and complex purification steps, results in significant waste emissions, and consumes enormous amounts of energy.

[0006] CN109772353A discloses a catalyst for the preparation of 1,4-butynediol and its preparation method. Although the catalyst has the advantages of high activity and high yield of propynediol, the selectivity of propynediol is only 20.5-28.7% according to the published examples, and the yield of the target product is still low.

[0007] CN 113751039A discloses an acetylation catalyst for the synthesis of propynyl alcohol, its preparation method, and its application. Based on Cu-based catalysts, an anionic promoter and surface activity are introduced to prepare an Au-Cu2C2 catalyst with interfacial activity. Although it can improve the selectivity and yield of propynyl alcohol to a certain extent, the catalyst active component uses the precious metal Au, resulting in high catalyst cost.

[0008] CN103896737A provides a method for preparing propargyl alcohol using a microstructured reactor, which uses Grignard reagent, acetylene, and aldehyde or ketone as raw materials. The method uses a microstructured reactor to ensure intrinsic safety, but Grignard reagent is expensive.

[0009] CN 111747824A discloses a method for the continuous and rapid preparation of propargyl alcohol using a microreactor. Under anhydrous and oxygen-free conditions, metallic magnesium, elemental iodine, and a solvent are added to the reactor and stirred until homogeneous. Then, a haloalkane is added dropwise while continuously stirring, resulting in a alkyl magnesium halide Grignard reagent. In the microreactor, using the prepared alkyl magnesium halide and acetylene as raw materials, a Grignard exchange reaction is carried out under continuous flow conditions to obtain acetylenyl magnesium halide. Then, using acetylenyl magnesium halide and formaldehyde as raw materials, a nucleophilic addition reaction is carried out under continuous flow conditions to prepare propargyl alcohol. However, the Grignard reagent needs to be prepared under anhydrous and oxygen-free conditions, which is not only complex to operate but also costly.

[0010] CN108503505A uses the synthesis catalyst of 1,4-butynediol as a catalyst to catalytically crack 1,4-butynediol to prepare propynyl alcohol. However, this method has problems such as low yield, slow reaction rate, and the need to add reaction solvent and difficult separation of catalyst. In addition, the whole process needs to be operated under acetylene protection, which not only leads to high production cost, but also poses potential operational risks.

[0011] CN109317156A discloses a solid superbase catalyst and process conditions for the cracking of 1,4-butynediol to propynyl alcohol, which can increase the conversion rate of butynediol to 46.3% and the selectivity of propynyl alcohol to 57.4%. However, it has disadvantages such as more by-products, low feed space velocity, and rapid catalyst deactivation.

[0012] It is evident that existing propynyl alcohol preparation processes all have significant drawbacks, and the question of whether a simpler method for preparing propynyl alcohol can be provided is an urgent problem to be solved. Summary of the Invention

[0013] This invention addresses the shortcomings of existing technologies by providing a method for the rapid preparation of propargyl alcohol using a fluidized bed reactor. Using 1,4-butynediol as a raw material, the product undergoes a catalytic cracking reaction in the fluidized bed reactor under the action of a catalyst to produce propargyl alcohol and formaldehyde. The products are separated and purified to obtain propargyl alcohol. The deactivated catalyst is regenerated in a catalyst regenerator and recycled. This invention features a safe cracking reaction process that does not use the hazardous gas acetylene. The single-pass conversion rate of 1,4-butynediol is ≥65%, and the main reaction selectivity in the products is ≥85%.

[0014] The specific technical solution adopted in this invention is as follows:

[0015] A method for the rapid preparation of propynyl alcohol using a fluidized bed reactor, the specific process flow is as follows:

[0016] 1,4-Butynediol is prepared into a solution with a mass fraction of 10%-55%, and the solvent used is one or more of water, ethanol, methanol, and isopropanol.

[0017] Choosing the above solvent to prepare the solution has several advantages: firstly, it allows 1,4-butynediol to have good fluidity at room temperature; secondly, it helps to reduce the partial pressure of the product during the reaction; and thirdly, it helps to suppress catalyst coking and inhibit side reactions.

[0018] The reaction solution is pressurized by a pump, and the raw material is heated to 120℃-360℃ by a heat exchanger. The material is fully atomized and then evenly sprayed into the fluidized bed reactor for reaction. The atomized raw material comes into uniform contact with the high-temperature pyrolysis catalyst and undergoes a pyrolysis reaction.

[0019] In the above reaction process, the reaction temperature in the fluidized bed reactor is 180℃-700℃, the reaction pressure is 0.1-0.6 MPa, the mass ratio of catalyst to raw material is 0.5-6.0:1, and the reaction time is 0.5s-30.0s;

[0020] The preferred reaction temperature is 300℃-600℃, the reaction pressure is 0.1-0.4 MPa, the mass ratio of catalyst to raw material is 1.0-6.0:1, and the reaction time is 1.5s-20.0s.

[0021] After the reaction, the reactants are separated from the catalyst. The separated reactants then enter a coarse separation section for further purification, and the separated catalyst is reactivated. Depending on the type of fluidized bed, separate gas-solid separators and catalyst reactivators can be installed, such as in riser reactors or downflow reactors; alternatively, separate gas-solid separators and catalyst reactivators can be omitted, such as in fixed fluidized bed reactors.

[0022] The catalyst used consists of a matrix, an active component, and an additive. The active component accounts for 8%-18% of the catalyst mass, the additive accounts for 0.2%-3%, and the remainder is the matrix.

[0023] The catalyst matrix is ​​composed of one or more of alumina, silica, activated carbon, magnesium oxide, calcium oxide, and silica-alumina molecular sieves, preferably one or more of alumina, silica, and silica-alumina molecular sieves; the active component is composed of one or more of nickel oxide, molybdenum oxide, zinc oxide, copper oxide, and cobalt oxide; and the additives are composed of one or more of sodium oxide, potassium oxide, bismuth oxide, titanium oxide, and zirconium oxide.

[0024] The catalyst described above can be prepared by first mixing the matrix in a certain proportion and slurrying it, then spray-molding, drying, and calcining it to obtain the matrix, which is then mixed with the active component and additives. Alternatively, it can be prepared by a one-pot method where the matrix, active component, and additives are first mixed in a certain proportion and slurryed, then spray-molded, dried, and calcined. Examples provided by the inventors are as follows:

[0025] The specific preparation process of catalyst 1 is as follows:

[0026] ① The preparation process of the carrier matrix is ​​as follows: Weigh 5.2 parts by weight of alumina dry adhesive, 1 part by weight of hydrochloric acid, and 60 parts by weight of water, mix them evenly into a slurry, add 81.9 parts by weight of silica powder, and continue stirring until uniform. Spray the mixed material into shape using an LPG-5 centrifugal spray gun, controlling the average particle size of the carrier matrix to be 55-75 μm. The shaped carrier is then calcined in a muffle furnace at a temperature of 350℃-600℃ for 2-12 hours.

[0027] ② Take 9.2 parts of copper nitrate, 3.2 parts of cobalt nitrate, and 0.5 parts of bismuth nitrate to prepare an impregnation solution. After uniformly and fully impregnating the above carrier matrix with 50-90 parts of water, dry it at 105-180℃ for 6-24 hours and calcine it at 350-580℃ for 2-12 hours to prepare the solution.

[0028] Catalyst 2 was prepared using a one-pot method, and the specific process is as follows:

[0029] Weigh 40 parts of alumina dry adhesive, 8 parts of hydrochloric acid, and 60 parts of water, and mix them evenly into a slurry. Add 55.5 parts of silica powder and stir evenly. Then add 6.3 parts of copper nitrate, 2.9 parts of cobalt nitrate, and 0.3 parts of bismuth nitrate and stir thoroughly. Spray the mixture using an LPG-5 centrifugal spray gun, controlling the average particle size of the carrier matrix to be 55-75 μm. Calcine the shaped carrier in a muffle furnace at 350-580℃ for 2-12 hours to prepare the final product.

[0030] The catalyst can be recycled through a regeneration process after use. The catalyst regenerator used during regeneration is one of the following: riser regenerator, dense phase fluidized bed regenerator, tank fluidized bed regenerator, or fixed fluidized bed regenerator. The regeneration temperature is 400℃-700℃ and the pressure is 0.1-0.6 MPa. Compressed air or oxygen needs to be added during the regeneration process. To ensure the regeneration temperature, fuel or heat extraction measures can also be added. To ensure the reaction effect, the residual carbon of the catalyst after regeneration is controlled to be <0.1 wt%.

[0031] After the reaction, the product and catalyst enter a gas-solid separator for separation. The separated catalyst enters a catalyst regenerator for catalyst reactivation. The reactivated catalyst is then recycled.

[0032] The separated products enter the product separation unit for crude product separation. The hydrocarbons other than propargyl alcohol are used as fuel for the system, while the crude propargyl alcohol enters the distillation column for purification.

[0033] The various devices used in the above reactions are all commonly used existing devices. The inventors have recombined them and defined the process parameters.

[0034] Compared with the prior art, the advantages of the present invention are as follows:

[0035] 1. The reaction process does not use gaseous acetylene, making the preparation method safer;

[0036] 2. The fluidized bed reactor facilitates continuous input and output of solid catalysts, thus addressing the issue of high catalyst deactivation rates; the internal temperature of the bed is uniform, making it easy to control side reactions.

[0037] 3. The ratio of catalyst to reactants has been increased, with the mass ratio of catalyst to reactants reaching 1.0-6.0:1, thereby improving the raw material conversion rate. The single-pass conversion rate of 1,4-butynediol is ≥65%.

[0038] 4. Using a special catalyst combination, it has better selectivity for the target product, with the main reaction selectivity in the product being ≥85%. Attached Figure Description

[0039] Figure 1 This is a process flow diagram of the equipment used in Example 1 for the rapid preparation of propynyl alcohol using a fluidized bed reactor;

[0040] Figure 2 This is a process flow diagram of the equipment used in Example 3 for the rapid preparation of propynyl alcohol using a fluidized bed reactor;

[0041] In the diagram: 1 is the regeneration reactor; 2 is the pyrolysis reactor; 3 is the gas-solid separator; 4 is the product separation tower; and 5 is the fixed fluidized bed. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and all percentages are by weight. The reactors used are all existing, commonly used devices.

[0043] Example 1

[0044] Catalyst 1 was prepared by first preparing the support matrix and then impregnating the active component for experimental evaluation. The composition of catalyst 1 is shown in Table 1.

[0045] Table 1

[0046]

[0047] The specific preparation process of catalyst 1 is as follows:

[0048] ① The preparation process of the carrier matrix is ​​as follows: Weigh 5.2 parts by weight of alumina dry adhesive, 1 part by weight of hydrochloric acid, and 60 parts by weight of water, mix them evenly into a slurry, add 81.9 parts by weight of silica powder, and continue stirring until uniform. Spray the mixed material into shape using an LPG-5 centrifugal spray gun, controlling the average particle size of the carrier matrix to be 55-75 μm. The shaped carrier is then calcined in a muffle furnace at a temperature of 350℃-600℃ for 2-12 hours.

[0049] ② Take 9.2 parts by weight of copper nitrate, 3.2 parts by weight of cobalt nitrate and 0.5 parts by weight of bismuth nitrate to prepare an impregnation solution, and 50-90 parts by weight of water solvent. After uniformly and fully impregnating the above-mentioned carrier matrix, dry at 120°C for 12 hours and calcine at 550°C for 6 hours to prepare the product.

[0050] Adopting such Figure 1 The evaluation was conducted using an evaluation device, and the reaction conditions were as follows:

[0051] 1,4-Butynediol was prepared into a 25% aqueous solution. The feedstock was heated to 140℃-160℃ and atomized and uniformly sprayed into the fluidized bed reactor through a feedstock atomizer. The atomized feedstock came into uniform contact with the high-temperature pyrolysis catalyst and underwent a pyrolysis reaction. The catalyst and the reactant flowed upwards in the same direction to react. The inlet catalyst temperature was controlled at 400-420℃, the feed material temperature was controlled at 140-160℃, the catalyst to material weight ratio was 5:1, the reactor outlet pressure was 0.30-0.35 MPa, and the average reaction time was 2.8 s.

[0052] The reaction products and the catalyst to be regenerated are separated in a gas-solid separator at an operating pressure of 0.26-0.29 MPa using an adiabatic system. The separated catalyst to be regenerated is then regenerated in a catalyst reactivator at an operating temperature of 450-500℃ and an operating pressure of 0.32-0.35 MPa. Air and natural gas are added during the reaction process to control the oxygen content in the reactivation tail gas at 1.5-2.8% (v / v). The regenerated catalyst is then recycled.

[0053] The separated products are then sent to the product separation unit for propynyl alcohol purification. The hydrocarbons other than propynyl alcohol and butynediol are removed and used as fuel for the system. The reaction results are shown in Table 3.

[0054] Example 2

[0055] Catalyst 2, prepared by a one-pot method, was used for experimental evaluation. The composition of the catalyst is shown in Table 2.

[0056] Table 2. Composition of catalysts used in the experiment.

[0057]

[0058] Catalyst 2 was prepared using a one-pot method, and the specific process is as follows:

[0059] Weigh 40 parts of alumina dry adhesive, 8 parts of hydrochloric acid, and 60 parts of water, and mix them evenly into a slurry. Add 55.5 parts of silica powder and stir evenly. Then add 6.3 parts of copper nitrate, 2.9 parts of nickel nitrate, and 0.3 parts of bismuth nitrate and stir thoroughly. Spray the mixture using an LPG-5 centrifugal spray gun, controlling the average particle size of the carrier matrix to be 55-75 μm. Calcination of the shaped carrier in a muffle furnace at 540℃ for 4 hours yields the final product.

[0060] Adopting such Figure 1 The evaluation was conducted using an evaluation device, and the reaction conditions were as follows:

[0061] 1,4-Butynediol was prepared into a 35% solution using water and ethanol in a mass ratio of 1:5. The feedstock was heated to 140℃-160℃ and atomized and uniformly sprayed into the fluidized bed reactor using a feed atomizer. The atomized feedstock came into uniform contact with the high-temperature pyrolysis catalyst and underwent a pyrolysis reaction. The catalyst temperature at the reactor inlet was controlled at 450-470℃, the feed temperature at 140-160℃, the catalyst-to-feed ratio at 4.7-4.9:1, the reactor outlet pressure at 0.22-0.24 MPa, and the average reaction time at 4.2 s.

[0062] The reaction products and the catalyst to be generated are fed into a gas-solid separator for separation. The separator operates at a pressure of 0.21-0.23 MPa and is operated in an adiabatic manner.

[0063] The separated spent catalyst enters a catalyst reactivator for reactivation. The reactivation reactor operates at a temperature of 450-500℃ and a pressure of 0.28-0.32 MPa. Air and natural gas are added during the reaction process to control the oxygen content in the reactivation tail gas at 1.1-2.3% (v / v). The reactivated catalyst is recycled. The separated product enters a product separation unit for propynyl alcohol purification, removing hydrocarbons other than propynyl alcohol and butynediol, which are then used as fuel for the system. The reaction results are shown in Table 3.

[0064] Example 3

[0065] Catalyst 1 prepared in Example 1 was used for experimental evaluation, and the following methods were employed: Figure 2 The evaluation device and evaluation conditions are as follows:

[0066] Reaction process: 1,4-Butynediol was prepared into a 15% solution using water as the solvent. The raw material was heated to 140℃-160℃ and atomized uniformly into the fluidized bed reactor using a raw material atomizer. The atomized raw material came into uniform contact with the high-temperature pyrolysis catalyst and underwent a pyrolysis reaction. The reactor reaction temperature was controlled at 320-350℃, the catalyst-to-material feed ratio was 4.0-5.0:1, the reactor outlet pressure was 0.12-0.15 MPa, and the average reaction time was 19.5 s. After the reaction, the product and the catalyst were separated at the top of the fixed fluidized bed reactor. The separated product entered the product separation unit for propynediol purification. The reaction results are shown in Table 3.

[0067] Regeneration process: As the reaction proceeds, the catalyst activity decreases. The reaction feed is stopped, and nitrogen or steam is used for purging and replacement. The process is then switched to regeneration. The temperature inside the reactor is raised to 450-520℃. Air or oxygen is added during the regeneration process to control the carbon dioxide content in the regeneration tail gas to be below 0.1% (v / v). Once the catalyst is reactivated, the system is cooled and replaced before entering the reaction process. This process is repeated.

[0068] Comparative Example 1

[0069] Catalyst 1, prepared according to Example 1, was used for experimental evaluation in a fixed-bed reaction apparatus. The evaluation conditions were as follows:

[0070] Reaction process: 1,4-Butynediol was prepared into a 15% solution using water as the solvent. The raw material was heated to 140℃-200℃ and atomized uniformly into the reactor using a raw material atomizer. The atomized raw material came into uniform contact with the high-temperature pyrolysis catalyst and underwent a pyrolysis reaction. The reactor reaction temperature was controlled at 320-350℃, the catalyst loading was 5g, the feed rate was 10g / min, the average reaction time was 0.7s, and the reactor outlet pressure was atmospheric pressure. The products after the reaction were analyzed and the results are shown in Table 3.

[0071] Table 3

[0072]

[0073]

[0074] As can be seen from the experimental results of Examples 1 and 2 in Table 3, the catalysts prepared by both methods exhibit excellent performance, with a single-pass conversion rate of ≥65% and a main reaction selectivity of ≥85% in the product. Example 2 shows higher conversion rate and main reaction selectivity, making it the best example overall. Comparing Examples 1 and 3, the experimental results show that Example 3 has a higher raw material conversion rate, but poor target product selectivity, which is presumably caused by the longer reaction time and secondary reactions of the target product.

[0075] Comparing Example 1 and Comparative Example 1, it can be seen that Comparative Example 1 uses a fixed-bed reactor, which has a short reaction time and a low agent-to-oil ratio. This results in not only a low raw material conversion rate but also a low selectivity for the main reaction.

[0076] For those skilled in the art, the specific embodiments are merely illustrative descriptions of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A method for rapid production of propiolic alcohol using a fluidized bed reactor, characterized by: The specific process flow is as follows: 1,4-butynediol is configured into a solution with a mass fraction of 10%-55%, the reaction solution is pressurized by a pump, the raw material is heated to 120-360 DEG C through a heat exchanger, and then the material is fully atomized and uniformly sprayed into a fluidized bed reactor for reaction, the atomized raw material uniformly contacts the high-temperature cracking catalyst and cracking reaction occurs; The fluidized bed reactor is one or more of a riser reactor, a downflow tube reactor, and a fixed fluidized bed reactor; the reaction temperature of the fluidized bed reactor is 180-700 DEG C, the reaction pressure is 0.1-0.6 MPa, the mass ratio of catalyst to raw material is 0.5-6.0:1, and the reaction time is 0.5-30.0 s; The catalyst is composed of a substrate, an active component, and an additive, the active component accounts for 8%-18% of the mass percentage of the catalyst, the additive accounts for 0.2%-3%, and the rest is the substrate; the catalyst substrate is composed of one or more of alumina, silica, activated carbon, magnesium oxide, calcium oxide, and silica-alumina molecular sieve; the active component is composed of one or more of nickel oxide, molybdenum oxide, zinc oxide, copper oxide, and cobalt oxide; and the additive is composed of one or more of sodium oxide, potassium oxide, bismuth oxide, titanium oxide, and zirconium oxide.

2. The method for rapidly preparing propiolic alcohol using a fluidized bed reactor according to claim 1, wherein: When 1,4-butynediol is configured into a solution, the solvent used is one or more of water, ethanol, methanol, and isopropanol. 3.The method for rapidly preparing propiolic alcohol using a fluidized bed reactor according to claim 1, wherein: The reaction temperature of the fluidized bed reactor is 300-600 DEG C, the reaction pressure is 0.1-0.4 MPa, the mass ratio of catalyst to raw material is 1.0-6.0:1, and the reaction time is 1.5-20.0 s.

4. The method for rapidly preparing propiolic alcohol using a fluidized bed reactor according to claim 1, wherein: The catalyst substrate is composed of one or more of alumina, silica, and silica-alumina molecular sieve.

5. The method for rapidly preparing propiolic alcohol using a fluidized bed reactor according to claim 1, wherein the fluidized bed reactor is a fluidized bed reactor having a fluidized bed of a solid material. The product and the catalyst after the reaction enter a gas-solid separator for separation, the separated catalyst enters a catalyst regenerator for catalyst rejuvenation, and the rejuvenated catalyst is recycled; The separated product enters a product separation unit for crude separation, and the carbon, hydrogen, and oxygen materials other than propargyl alcohol are used as fuel required by the system, and the crude propargyl alcohol enters a rectifying column for refined separation. 6.The method for rapidly preparing propiolic alcohol using a fluidized bed reactor according to claim 1, wherein: The catalyst regenerator is one of a riser regenerator, a dense-phase fluidized bed regenerator, a tank-type fluidized bed regenerator, and a fixed fluidized bed regenerator, the regeneration temperature is 400-700 DEG C, the pressure is 0.1-0.6 MPa, compressed air or oxygen is needed for the regeneration process, and the carbon residue of the regenerated catalyst is controlled to be less than 0.1 wt% to ensure the reaction effect.

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