High-temperature pyrolysis reaction system and application thereof
By using a two-stage high-temperature pyrolysis reaction system and a biomimetic catalyst, combined with a microchannel separator, the problems of low conversion rate and poor selectivity in isobutyric anhydride pyrolysis were solved, and efficient DMK preparation was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YIXING HENGXING FINE CHEM
- Filing Date
- 2026-03-03
- Publication Date
- 2026-06-26
Smart Images
Figure CN122273406A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical synthesis technology, and specifically discloses a high-temperature pyrolysis reaction system and its application. Background Technology
[0002] 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (CBDO), a key raw material for the production of high-performance Tritan copolyesters, has long been subject to a technological monopoly by foreign companies. The core of CBDO preparation lies in obtaining dimethyl ketene (DMK) intermediates, currently the mainstream process being the high-temperature pyrolysis of isobutyric acid or isobutyric anhydride. This process involves multiple steps, including temperature-increasing pyrolysis, rapid cooling, gas-liquid separation, and product collection. Among these, uniform heating of the raw materials, rapid cooling of the pyrolysis gas, control of the mass transfer process, and suppression of side reactions are crucial factors determining product yield and selectivity.
[0003] While existing technologies have attempted to improve conversion rates using molecular sieves or silica-coated catalysts, most employ a single catalyst and fail to fully consider the differences in the cracking mechanisms of isobutyric acid and isobutyric anhydride, resulting in limited single-pass feed utilization. Regarding catalyst structure, existing patents primarily focus on optimizing micropores, neglecting the impact of the macroscopic packing structure on system pressure drop and mass transfer. Conventional powder or granular packing methods often lead to high bed resistance and severe backmixing, making precise control of the cracking time difficult and exacerbating the reverse reaction. Furthermore, while introducing low-carbon hydrocarbons or organic acids can reduce carbon buildup, this often introduces additional impurities, increasing the difficulty of subsequent separation and easily leading to catalyst deactivation.
[0004] In the product separation stage, existing methods typically cool the pyrolysis gas as a whole, which suffers from low heat exchange efficiency. Insufficient cooling leads to prolonged contact time of the product in the high-temperature zone, significantly exacerbating the reverse reaction and causing the target product to polymerize, thus reducing selectivity. In summary, existing technologies still suffer from numerous shortcomings, including high isobutyric acid content, low DMK yield, easy catalyst carbonization, and poor bed mass transfer. Therefore, there is an urgent need to develop a high-temperature pyrolysis reaction system that achieves high conversion, high selectivity, and efficient mass transfer and separation capabilities, based on the reaction mechanism. Summary of the Invention
[0005] To address the problems existing in the prior art, the first aspect of this invention proposes a high-temperature pyrolysis reaction system for preparing dimethyl ketene, characterized in that it comprises: The first preheater, the outlet of which is connected to the inlet of the mixer and the inert gas pipeline; A mixer that receives inert gas and feedstock from a first preheater for mixing the vaporized feedstock with the inert gas; A high-temperature pyrolysis reactor, wherein the inlet of the high-temperature pyrolysis reactor is connected to the outlet of the mixer, and the interior of the high-temperature pyrolysis reactor is provided with a first catalyst bed, an intermediate mixing zone and a second catalyst bed in sequence along the direction of raw material flow; The first preheater and the second preheater are used to vaporize the raw materials and intermediate components, respectively. The intermediate mixing zone is provided with an intermediate air inlet, which is connected to the outlet of the second preheater; A microchannel separator, the inlet of which is connected to the outlet of the high-temperature pyrolysis reactor, is used to rapidly cool the pyrolysis mixture. A gas-liquid separation and collection system, wherein the inlet of the gas-liquid separation and collection system is connected to the outlet of the microchannel separator, for collecting the gas phase containing the target product.
[0006] In some specific embodiments of the high-temperature pyrolysis reaction system for preparing dimethyl ketene in the first aspect, the inlet of the mixer is connected to the outlet of the first preheater and the inert gas pipeline, for mixing the vaporized feedstock with the inert gas and conveying it to the high-temperature pyrolysis reactor; The inlet of the high-temperature pyrolysis reactor is connected to the outlet of the mixer, and the high-temperature pyrolysis reactor is provided with a first catalyst bed, an intermediate mixing zone and a second catalyst bed. The intermediate mixing zone is connected to the outlet of the second preheater and is used to receive the preheated intermediate components; The vaporized feedstock undergoes a catalytic reaction in the first catalyst bed to obtain a first cracked gas. The first cracked gas is mixed with the preheated intermediate components and enters the second catalyst bed to undergo a catalytic reaction to obtain a high-temperature cracked mixed gas.
[0007] In some specific embodiments of the high-temperature pyrolysis reaction system for preparing dimethyl ketene in the first aspect, the inlet of the gas-liquid separation and collection system is connected to the outlet of the microchannel separator for separating the condensate from the gas phase containing the target product.
[0008] The microchannel separator is equipped with a variable diameter straight pipe channel inside, and the ratio of the inlet inner diameter to the outlet inner diameter of the variable diameter straight pipe channel is 1:1 to 8:1.
[0009] In some specific embodiments of the high-temperature pyrolysis reaction system for preparing dimethyl ketene in the first aspect, a condenser sleeve with a cooling medium is provided on the outside of the microchannel separator.
[0010] In some specific embodiments of the high-temperature pyrolysis reaction system for preparing dimethyl ketene in the first aspect, the gas-liquid separation and collection system includes an absorption tower or a freezer.
[0011] In some specific embodiments of the high-temperature cracking reaction system for preparing dimethyl ketene in the first aspect, the first catalyst bed is filled with a first catalyst, and the second catalyst bed is filled with a second catalyst, wherein both the first catalyst and the second catalyst are catalysts with a biomimetic structure of cancellous bone from animals.
[0012] In some specific embodiments of the high-temperature cracking reaction system for preparing dimethyl ketene in the first aspect, the preparation process of the first catalyst and the second catalyst includes: (a) Obtaining the model structure: First, the cancellous bone of the animal is scanned by Micro-CT, and then the scanned images are used to create a three-dimensional digital model to obtain the model structure.
[0013] (b) Preparation of printing slurry: The catalyst substrate, photosensitive resin, binder, dispersant and deionized water are mixed evenly to form a slurry.
[0014] (c) Based on the model structure obtained in a, the slurry obtained in b is 3D printed to obtain the initial block.
[0015] (d) The initial bulk material is dried and calcined to obtain a biomimetic monolithic catalyst.
[0016] The catalyst material for the first stage is selected from molecular sieves, specifically MOR, ZSM, SAPO-34, Silicalite1, Y-type molecular sieves, beta molecular sieves, and FER. The catalyst material for the second stage is a metal oxide, such as SiO2, TiO2, MgO, Al2O3, magnesium aluminum spinel, etc. In some specific embodiments of the high-temperature cracking reaction system for preparing dimethyl ketene in the first aspect, the main material of the first catalyst is a molecular sieve; and the main material of the second catalyst is a metal oxide.
[0017] In some specific embodiments of the high-temperature cracking reaction system for preparing dimethyl ketene in the first aspect, the catalyst porosity is 30-80%. In some specific embodiments of the high-temperature pyrolysis reaction system for preparing dimethyl ketene in the first aspect, the shell of the high-temperature pyrolysis reactor is equipped with a heating device to maintain the internal pyrolysis temperature at 300~800℃; the ratio of the internal height of the reactor to the thickness of the catalyst bed is set such that the residence time of gas in each catalyst bed is 0.01~10 s.
[0018] A second aspect of the present invention provides a method for preparing dimethyl ketene using any of the high-temperature pyrolysis reaction systems described in the first aspect, characterized by comprising the steps of: Step 1: Isobutyric anhydride or isobutyric acid liquid is vaporized in the first preheater, and the vaporized raw material gas is mixed evenly with the inert gas in the mixer; Step 2: The intermediate components are fed into the second preheater for vaporization; Step 3: The mixed gas obtained in Step 1 is introduced into the high-temperature pyrolysis reactor. It first undergoes preliminary pyrolysis in the first catalyst bed to obtain the first pyrolysis gas. The intermediate component after vaporization in Step 2 enters the intermediate mixing zone and mixes with the first pyrolysis gas. The mixed gas then enters the second catalyst bed to obtain the high-temperature pyrolysis mixed gas after the reaction. Step 4: Cool the high-temperature pyrolysis mixture after the reaction, separate the gas and liquid, and collect the products to obtain dimethyl ketone.
[0019] In some specific embodiments of the method described in the second aspect, the vaporization temperature in step 1 is controlled to be 200~280°C.
[0020] In some specific embodiments of the method described in the second aspect, in step 2, the intermediate component is selected from at least one of acetone, isobutyl acetate, butyl propionate, butyl butyrate, n-butyl ether, and carbon dioxide.
[0021] In some specific embodiments of the method described in the second aspect, the intermediate component after vaporization in step 2 enters the intermediate mixing zone from the intermediate air inlet in the middle of the reactor and mixes with the first cracked gas to obtain a mixed gas, wherein the content of the intermediate component is 0.01~10% based on the total amount of inert gas, raw materials and intermediate components.
[0022] In some specific embodiments of the method described in the second aspect, the mixed gas enters a second catalyst bed for further pyrolysis reaction, the pyrolysis temperature is maintained at 300~800℃, and the reaction pressure is 10~120kPa.
[0023] In some specific embodiments of the method described in the second aspect, the time for the mixed gas obtained in step 1 to undergo preliminary pyrolysis in the first catalyst bed is 0.01 to 10 s.
[0024] In some specific embodiments of the method described in the second aspect, the gas pyrolysis time after mixing in step 3 and entering the second catalyst bed is 0.01~10s.
[0025] The collected components were analyzed by gas chromatography under the following conditions: Chromatographic column: RTX®-Wax capillary column (PEG): 50 m × 0.20 mm × 0.5 μm Heating conditions: 180 °C held for 1 min, then increased to 200 °C at 10 °C / min and held for 16 min.
[0026] The cancellous bone of the animal in this invention can be selected from the vertebrae, lumbar vertebrae, tibia and femur of cattle, pigs and horses, wherein Examples 1, 2 and 1-1 are lumbar vertebrae of cattle.
[0027] Advantages of this invention: The high-temperature pyrolysis reaction system of this invention significantly improves the feed conversion rate and the selectivity of the target product by employing a two-stage reactor design and loading differentiated catalysts, combined with intermediate component feeding between the two packing stages. The biomimetic monolithic catalyst macroscopically solves the problems of poor mass transfer, high pressure resistance, and severe backmixing caused by traditional packing materials, achieving precise control of the pyrolysis time. Combined with the rapid cooling technology achieved by the variable-diameter microchannel separator, it effectively curbs the secondary polymerization and reverse reaction of the product at high temperatures. Through synergistic optimization of reactor configuration, catalyst structure, and separation technology, the entire system effectively suppresses carbon deposition while achieving efficient and stable preparation of dimethyl ketene. Furthermore, this technology has good scalability. A complete high-temperature pyrolysis reaction system, encompassing pyrolysis reactor design, catalyst structure design, and improved separation technology, has been developed and applied to the pyrolysis of isobutyric anhydride to produce dimethyl ketene, achieving high feed conversion rate and high selectivity of the target product. Attached Figure Description
[0028] Figure 1 This diagram shows the connection diagram of each device in the high-temperature pyrolysis reaction system of the present invention; 11. First preheater; 12. Second preheater; 2. Mixer; 4. High-temperature pyrolysis reactor; 41. First catalyst bed; 42. Intermediate mixing zone; 43. Second catalyst bed; 5. Microchannel separator; 6. Gas-liquid separation and collection system. Detailed Implementation
[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0030] A high-temperature pyrolysis reaction system for preparing dimethyl ketene, comprising, The outlet of the first preheater 11 is connected to the inlet of the mixer 2 and the inert gas pipeline. Mixer 2, which receives inert gas and raw material from first preheater 11, is used to mix vaporized raw material with inert gas; The first preheater 11 is used to vaporize the raw material, wherein isobutyric anhydride / isobutyric acid liquid enters the first preheater 11 through a metering pump for vaporization to obtain vaporized raw material.
[0031] The high-temperature pyrolysis reactor 4 has its inlet connected to the outlet of the mixer 2. Inside the high-temperature pyrolysis reactor 4, a first catalyst bed 41, an intermediate mixing zone 42, and a second catalyst bed 43 are arranged sequentially along the raw material flow direction. The second preheater 12 is used to vaporize intermediate components (acetone, isobutyl acetate, butyl propionate, butyl butyrate, n-butyl ether, carbon dioxide, etc., heated to a suitable temperature according to the different intermediate components). The intermediate mixing zone 42 is provided with an intermediate air inlet, which is connected to the outlet of the second preheater 12 and is used to deliver the vaporized intermediate components to the intermediate mixing zone.
[0032] The inlet of the mixer 2 is connected to the outlet of the first preheater 11 and the pipeline of inert gas (nitrogen, argon, helium), and is used to mix the vaporized raw material F1 with the inert gas G1 and transport it to the high-temperature pyrolysis reactor 4. The vaporized raw material F1 is mixed with the inert gas (nitrogen, argon, helium) in the mixer 2 to obtain a mixed gas, which then enters the high-temperature pyrolysis reactor 4.
[0033] The mixed gas is introduced into the high-temperature pyrolysis reactor 4 and first undergoes preliminary pyrolysis through the first catalyst bed 41 to obtain the first pyrolysis gas. The vaporized intermediate component F2 enters the intermediate mixing zone 42 and mixes with the first pyrolysis gas. The mixed gas (mixture A) enters the second catalyst bed 43 and is pyrolyzed again to obtain the high-temperature pyrolysis mixed gas after the reaction.
[0034] The shell of the high-temperature pyrolysis reactor 4 is equipped with a heating device to maintain the pyrolysis temperature of the first catalyst bed 41 and the second catalyst bed 43 inside at 300~800℃.
[0035] The ratio of the internal height of the high-temperature pyrolysis reactor 4 to the thickness of the catalyst bed, and the flow rate of the mixed gas in the first catalyst bed 41, are set such that the residence time of the mixed gas in the first catalyst bed 41 is 0.01~10 s.
[0036] The ratio of the internal height of the reactor to the thickness of the catalyst bed, and the flow rate of the mixture A in the second catalyst bed 43, are set such that the residence time of the mixed gas in the second catalyst bed 43 is 0.01~10 s.
[0037] The high-temperature pyrolysis mixture from the pyrolysis reactor 4 is cooled by the microchannel separator 5 and then enters the gas-liquid separation and collection system 6 to obtain liquid and gas. The gas is then absorbed by solvent / frozen with liquid nitrogen to obtain the target product.
[0038] The microchannel separator 5 has its inlet connected to the outlet of the high-temperature pyrolysis reactor 4 and is used to rapidly cool the high-temperature pyrolysis mixture. The gas-liquid separation and collection system 6 has its inlet connected to the outlet of the microchannel separator 5 and is used to separate the condensate from the gas phase containing the target product. The gas-liquid separation and collection system 6 includes an absorption tower or a freezer.
[0039] Preferably, the microchannel separator is provided with a condenser sleeve with a cooling medium on its outer side.
[0040] In some preferred embodiments, the microchannel separator 5 is provided with a variable diameter straight pipe channel inside, and the ratio of the inner diameter of the inlet to the inner diameter of the outlet of the variable diameter straight pipe channel is 1:1 to 8:1.
[0041] The first catalyst bed is filled with a first catalyst 41, and the second catalyst bed 43 is filled with a second catalyst. Both the first catalyst and the second catalyst are catalysts with a biomimetic structure of cancellous bone from animals, and the porosity of the catalysts is 30-80%.
[0042] In some specific embodiments of the high-temperature cracking reaction system for preparing dimethyl ketene in the first aspect, the main material of the first catalyst is a molecular sieve.
[0043] The catalyst material for the first stage is selected from molecular sieves, specifically MOR, ZSM, SAPO-34, Silicalite1, Y-type molecular sieves, beta molecular sieves, and FER.
[0044] The main material of the second catalyst is a metal oxide, such as SiO2, TiO2, MgO, Al2O3, magnesium aluminum spinel, etc.
[0045] Example 1 Taking ZSM as the main material as an example, the preparation process of the first catalyst is explained as follows: (a) Obtaining the model structure: First, the cancellous bone of the animal is scanned by Micro-CT, and then the scanned images are used to create a three-dimensional digital model to obtain the model structure.
[0046] (b) Preparation of printing slurry: 40 wt% catalyst host material (ZSM), 25 wt% epoxy acrylate resin, 8 wt% binder (hydroxypropyl methylcellulose), 7 wt% dispersant (4 wt% sodium dodecylbenzenesulfonate, 3 wt% silane coupling agent 3-trimethoxysilane propylene acrylate) and 20 wt% deionized water are mixed evenly to prepare slurry.
[0047] (c) Based on the model structure obtained in a, the slurry obtained in b is 3D printed to obtain the initial block.
[0048] (d) The initial bulk material was dried and calcined at 550℃ for 4-6 hours under air atmosphere by heating at a rate of 5℃ / min to obtain the biomimetic monolithic catalyst ZSM molecular sieve.
[0049] Example 1-1 Taking MgO as the main material as an example, the preparation process of the second catalyst is explained as follows: (a) Obtaining the model structure: First, the cancellous bone of the animal is scanned by Micro-CT, and then the scanned images are used to create a three-dimensional digital model to obtain the model structure.
[0050] (b) Preparation of printing slurry: 40 wt% catalyst host material (MgO), 25 wt% epoxy acrylate resin, 8 wt% binder (hydroxypropyl methylcellulose), 7 wt% dispersant (4 wt% sodium dodecylbenzenesulfonate, 3 wt% silane coupling agent 3-trimethoxysilane propylene acrylate) and 20 wt% deionized water are mixed evenly to prepare slurry.
[0051] (c) Based on the model structure obtained in a, the slurry obtained in b is 3D printed to obtain the initial block.
[0052] (d) The initial bulk material was dried and calcined at 550℃ for 4-6 hours under air atmosphere by heating at a rate of 5℃ / min to obtain a biomimetic monolithic catalyst MgO; Example 2 The present invention discloses a method for preparing dimethyl ketene using the aforementioned high-temperature pyrolysis reaction system, comprising the following steps: Step 1: Isobutyric anhydride is introduced into the first preheater 11 at a flow rate of 0.2 ml / min via a metering pump for vaporization at a vaporization temperature of 230℃. Specifically, the vaporized raw material gas is mixed evenly with N2 at a flow rate of 200 ml / min in a mixer 2. Acetone is vaporized in the second preheater 12 via a metering pump at a flow rate of 0.01 ml / min, and then enters the pyrolysis reactor through the inlet in the middle of the pyrolysis unit. The mixed gas passes through the first stage catalyst, which is a biomimetic monolithic catalyst ZSM molecular sieve; the first pyrolysis mixed gas is then mixed with acetone gas and then passes through the second stage catalyst, which is a biomimetic monolithic catalyst MgO.
[0053] Step 2: Acetone (intermediate component) is fed into the first preheater 12 and vaporized at 200~280°C. The vaporized intermediate component enters the intermediate mixing zone 42 from the intermediate air inlet of the high-temperature pyrolysis reactor and mixes with the first pyrolysis gas to obtain a mixed gas, wherein the content of the intermediate component is 4.0~6.0%.
[0054] Step 3: The mixed gas obtained in Step 1 is introduced into the high-temperature pyrolysis reactor 4. It first undergoes preliminary pyrolysis at 400°C through a first catalyst bed loaded with ZSM molecular sieve prepared in Example 1 to obtain the first pyrolysis gas. The time for the mixed gas obtained in Step 1 to undergo preliminary pyrolysis through the first catalyst bed is 0.1~10 s. The acetone (intermediate component) vaporized in Step 2 enters the intermediate mixing zone 42 and mixes with the first pyrolysis gas. The mixed gas then enters the second catalyst bed 43 loaded with biomimetic monolithic catalyst MgO for pyrolysis. The pyrolysis time is 0.1~10 s. The pyrolysis temperature is maintained at 300~800°C and the reaction pressure is 10~120 kPa.
[0055] Step 4: The high-temperature pyrolysis mixture after the reaction is cooled by the microchannel separator 5 and then enters the gas-liquid separation and collection system 6 to collect the liquid and gas components to obtain dimethyl ketene.
[0056] Comparative Example 1 Compared to Example 2, Comparative Example 1 is the same as Example 2 except that the intermediate component acetone in Example 2 is replaced with butyl butyrate.
[0057] Comparative Example 2 Compared to Example 2, Comparative Example 2 changed the first catalyst in Example 2 to a spherical ZSM molecular sieve with a particle size of 2-5 mm, and changed the second catalyst in Example 2 to a spherical MgO with a particle size of 2-5 mm. The rest was the same as in Example 2.
[0058] Comparative Example 3 Compared to Example 2, no acetone was introduced into the intermediate mixing zone in Comparative Example 3.
[0059] Comparative Example 4 Compared to Example 2, Comparative Example 4 uses ZSM molecular sieves for both the first and second catalyst stages.
[0060] Comparative Example 5 Compared to Example 2, Comparative Example 5 uses MgO catalysts for both the first and second stages of catalyst.
[0061] Example 3 The isobutyric anhydride conversion (%), DMK selectivity (%), single-pass yield (%), bed pressure drop / fluctuation (kPa), and catalyst coking (g / 100h) of Examples 2 and Comparative Examples 1 to 5 are shown in Table 1: Table 1
[0062] This high-temperature pyrolysis reaction system employs a two-stage differentiated catalyst configuration. The primary pyrolysis capability of the first stage molecular sieve and the deep conversion of metal oxides in the second stage satisfy the trade-off between activity and selectivity inherent in single catalysts. The monolithic catalyst with an animal cancellous bone-inspired structure provides high porosity, reduces bed pressure drop, and minimizes gas backmixing, thereby enabling precise control of gas residence time within 0.01–10 s to suppress reverse reactions. Furthermore, the introduction of acetone intermediates between the two bed stages can suppress carbon deposition by regulating the reaction environment, meeting the requirements of high feed conversion and high selectivity of the target product.
Claims
1. A high-temperature pyrolysis reaction system for preparing dimethyl ketene, characterized in that, include, The outlet of the first preheater (11) is connected to the inlet of the mixer (2) and the inert gas pipeline; A mixer (2) receives an inert gas and a raw material from a first preheater (11) for mixing the vaporized raw material with the inert gas; A high-temperature pyrolysis reactor (4) is provided inside the mixer (2) with its inlet connected to the outlet of the mixer (2). The reactor has a first catalyst bed (41), an intermediate mixing zone (42), and a second catalyst bed (43) arranged sequentially in the direction of raw material flow. The intermediate mixing zone (42) is provided with an intermediate air inlet, which is connected to the outlet of the second preheater (12) and is used to receive the preheated intermediate components. A microchannel separator (5) is provided, the inlet of which is connected to the outlet of the high-temperature pyrolysis reactor (4) for rapidly cooling the high-temperature pyrolysis mixture.
2. The high-temperature pyrolysis reaction system for preparing dimethyl ketene according to claim 1, characterized in that, After the vaporized raw material undergoes catalytic reaction in the first catalyst bed (41), it is mixed with the preheated intermediate components and enters the second catalyst bed (43) to undergo catalytic reaction, resulting in a high-temperature cracked mixed gas. The high-temperature cracked mixed gas is rapidly cooled by the microchannel separator (5) and then transported to the gas-liquid separation and collection system (6).
3. The high-temperature pyrolysis reaction system for preparing dimethyl ketene according to claim 2, characterized in that, The inlet of the gas-liquid separation and collection system (6) is connected to the outlet of the microchannel separator (5) for separating the condensate from the gas phase containing the target product; The microchannel separator (5) is provided with a variable diameter straight pipe channel inside, and the ratio of the inner diameter of the inlet to the inner diameter of the outlet of the variable diameter straight pipe channel is 1:1 to 8:
1.
4. The high-temperature pyrolysis reaction system for preparing dimethyl ketene according to claim 3, characterized in that, The microchannel separator (5) is provided with a condenser sleeve with a cooling medium on its outer side.
5. The high-temperature pyrolysis reaction system for preparing dimethyl ketene according to claim 4, characterized in that, It also includes a gas-liquid separation and collection system (6), the inlet of which is connected to the outlet of the microchannel separator (5) for collecting the gas phase containing the target product. The gas-liquid separation and collection system (6) includes an absorption tower or a freezer.
6. The high-temperature pyrolysis reaction system for preparing dimethyl ketene according to any one of claims 1 to 5, characterized in that, The first catalyst bed (41) is filled with a first catalyst, and the second catalyst bed (43) is filled with a second catalyst. Both the first catalyst and the second catalyst are catalysts with a biomimetic structure of cancellous bone from animals; and / or, the main material of the first catalyst is a molecular sieve; and the main material of the second catalyst is a metal oxide.
7. The high-temperature pyrolysis reaction system for preparing dimethyl ketene according to claim 1, characterized in that, The shell of the high-temperature pyrolysis reactor (4) is equipped with a heating device to maintain the internal pyrolysis temperature at 300~800℃; the ratio of the internal height of the reactor to the thickness of the catalyst bed is set so that the residence time of the gas in each catalyst bed is 0.01~10s.
8. A method for preparing dimethyl ketene using the high-temperature pyrolysis reaction system according to any one of claims 1 to 7, characterized in that, Including the following steps: Step 1: Isobutyric anhydride or isobutyric acid liquid is vaporized in the first preheater (11), and the vaporized raw material gas is mixed evenly with the inert gas in the mixer (2); Step 2: The intermediate components are fed into the second preheater (12) for vaporization; Step 3: The mixed gas obtained in Step 1 is introduced into the high-temperature pyrolysis reactor (4). It first undergoes preliminary pyrolysis in the first catalyst bed (41) to obtain the first pyrolysis gas. The intermediate component after vaporization in Step 2 enters the intermediate mixing zone (42) and mixes with the first pyrolysis gas. The mixed gas enters the second catalyst bed (43) to obtain the high-temperature pyrolysis mixed gas after reaction. Step 4: Cool the high-temperature pyrolysis mixture after the reaction, separate the gas and liquid, and collect the products to obtain dimethylketene.
9. The method according to claim 8, characterized in that, In step 1, the vaporization temperature is controlled at 200~280℃; and / or, in step 2, the intermediate component is selected from at least one of acetone, isobutyl acetate, butyl propionate, butyl butyrate, n-butyl ether, and carbon dioxide; and / or, the intermediate component after vaporization in step 2 enters the intermediate mixing zone (42) from the middle air inlet in the middle of the reactor and mixes with the first cracked gas to obtain a mixed gas, wherein, based on the total amount of inert gas, raw materials and intermediate components, the content of the intermediate component is 0.01~10%; and / or, the mixed gas enters the second catalyst bed (43) for further cracking reaction, wherein the cracking temperature is maintained at 300~800℃ and the reaction pressure is 10~120kPa.
10. The method according to claim 8, characterized in that, The time for the mixed gas obtained in step 1 to undergo preliminary pyrolysis in the first catalyst bed (41) is 0.01~10 s; and / or, the time for the mixed gas to enter the second catalyst bed (43) in step 3 to undergo pyrolysis is 0.01~10 s.