Apparatus and method for producing cyclohexanone by oxidizing cyclohexene using adipic acid production off-gas

Abstract

The present application relates to a kind of equipment and method for producing cyclohexanone by oxidizing cyclohexene with adipic acid production exhaust gas, raw gas A containing nitrous oxide in adipic acid production line is entered into raw gas A storage tank, then enter the deoxygenation device of pressure swing adsorption and remove oxygen, enter raw gas B storage tank, enter adipic acid production exhaust gas measuring tank;Through nitrogen tank, cyclohexene measuring tank, adipic acid production exhaust gas measuring tank, high-pressure heat exchanger, high-pressure preheater, fixed bed reactor, high-pressure cooler, high-pressure separator, deep cooling gas discharge tank and low-pressure separator processing generates cyclohexanone.The main purpose product cyclohexanone is generated, the selectivity of cyclohexene to cyclohexanone is greater than 98.0%, the conversion rate of nitrous oxide is greater than or equal to 99.9%, the exhaust gas containing nitrous oxide in adipic acid production line is only treated by removing oxygen, other gases contained do not need to be separated, the gas part of process device high-pressure separator refluxes in certain proportion, more stable.

Description

Technical Field

[0001] This invention belongs to the field of chemical manufacturing and relates to an equipment and method for oxidizing cyclohexene to produce cyclohexanone using the exhaust gas from the adipic acid production process, which contains nitrous oxide. Background Technology

[0002] N2O generated by human activities mainly comes from industrial and agricultural production. Since the Industrial Revolution, the concentration of N2O in the atmosphere has been continuously increasing, and it is projected that by 2100, the atmospheric concentration will be 1.5 times its current level. Therefore, the elimination of N2O has gradually become a hot topic in international research. A large amount of N2O is emitted from the Earth every year. Simply eliminating N2O through catalytic decomposition or selective catalytic reduction is not the best approach, especially for industrial production with high N2O emissions. For example, the traditional adipic acid production process generates a large number of byproducts, and the waste gas produced can increase the N2O content in the atmosphere by about 10%. Therefore, the recycling and utilization of N2O is of great significance. Domestic and international efforts are focused on further research and treatment to increase its utilization value, thereby achieving the goal of controlling N2O emissions. Research has found that N2O research mainly focuses on three aspects: firstly, N2O purification research; purified N2O can then be utilized to achieve N2O emission reduction. High-purity N2O can often be used in industries such as medical treatment, electronics manufacturing, and food processing aids, improving product quality while reducing production costs. This has led to a series of purification methods. Dolan Williams B et al. invented a method for separating N2O from a mixture of N2, O2, and N2O using Pressure Swing Adsorption (PSA) technology, selectively adsorbing N2O with an adsorbent to achieve purification. However, the mixed gases produced by industrial plants contain not only N2, O2, and N2O, but also large amounts of CO2 and other impurities. In response, Chevalier Gilbert et al. proposed using a selective permeation membrane to recover N2O from gas mixtures, but this is only suitable for recovering N2O from gas mixtures with small emissions. Nagamura Takashi invented a process for recovering N2O, first feeding N2O gas containing N2, O2, and water vapor into a compressor, then distilling it, with pure N2O discharged from the bottom of the distillation column. However, this N2O recovery process is complex to operate, and the lubricating oil in the compressor may cause secondary pollution to the N2O mixture. Therefore, the separation and purification of N2O is often costly and difficult to operate, which limits its further development. On the other hand, research focuses on the decomposition of N2O. Catalytic decomposition is an effective method for eliminating N2O. Based on the different active components of the catalyst, catalysts can be classified into ion-exchange molecular sieves, supported noble metals, and transition metal oxides, among others. L. Yan, R.J. Lu, and M. Tursun, among others, have reported on their applications. The adipic acid production unit of China National Petroleum Corporation's Liaoyang Petrochemical Company has a designed capacity of approximately 50,000 tons of N2O per year as a byproduct. The traditional N2O emission reduction unit uses catalytic decomposition technology from BASF (Germany) and a newly built unit using a process package from STEULER (Germany), aiming to reduce the emission of the inert greenhouse gas N2O.During the production of adipic acid, approximately 5330 kg of N2O gas is generated per hour. After treatment by the N2O emission reduction unit, over 95% of the N2O is decomposed into N2 and O2. The Liaohua Traditional N2O emission reduction unit, initially built in August 2007, mainly consists of an N2O emission reduction reaction unit, a waste heat recovery unit, and an air compressor unit. Completed and put into operation in March 2008, the Liaohua Traditional N2O emission reduction unit is designed to reduce N2O gas emissions by 41,000 tons annually, with a designed operating time of 8000 hours per year. The decomposition method releases the generated N2 and O2 into the atmosphere. Domestic adipic acid production plants produce approximately 1 million tons of N2O as a byproduct annually. While catalysts can decompose N2O into environmentally non-toxic and harmless N2 and O2, the stability of the catalyst and the demanding reaction conditions such as high temperature and high pressure required for the catalytic process pose challenges to the production process, and the effective reuse of N2O has generally not been achieved. The nitrous oxide decomposition method has high labor costs, power consumption, and equipment investment. Although it meets environmental protection requirements and international emission standards, this method only recovers heat. In contrast, the investment in this project, which uses nitrous oxide to oxidize cyclohexene to produce cyclohexanone, is not much larger than that of the decomposition method. The recovered heat is used to provide a heat source for subsequent products. Furthermore, while solving environmental problems, nitrous oxide is used as an oxidant in the oxidation of cyclohexene to cyclohexanone, reducing costs and achieving the goal of reuse. Finally, N2O is mainly used as an oxidant in chemical reactions. Among them, the oxidation of aromatics to phenol and the dehydrogenation of propane to propylene by N2O have been studied extensively. The key technology for producing phenol is the high selectivity of the catalyst. IVANOV.AA et al. reported the use of zeolite and its modified catalysts to catalyze the oxidation of benzene to phenol, with N2O as an oxygen carrier for the direct oxidation of benzene to phenol. In the reaction of benzene oxidation to phenol involving N2O, the main and side reactions are shown in equations (1) to (3).

[0003]

[0004] From a thermodynamic perspective, the reaction probabilities of equations (1), (2), and (3) are all very high. Due to the occurrence of side reactions, the selectivity of the products is greatly reduced, and greenhouse gas CO2 is also produced, resulting in very poor overall economic efficiency. In the process of N2O oxidation of propane to propylene, researchers have verified the different conversion rates exhibited by different oxidants under the same catalyst conditions. Bulánek R et al. investigated the effects of O2 and N2O as oxidants on the reaction activity of propane oxidation to propylene under the same reaction conditions, but catalyst deactivation was found. Therefore, for the propane dehydrogenation to propylene process, catalyst research is crucial, especially the stability and catalytic efficiency of the catalyst, which restricts its industrial production.

[0005] From a green chemistry perspective, research on using N2O as an oxidant in chemical raw material production is of great significance. It not only solves environmental problems but also brings significant economic benefits to production, representing a green chemical technology that turns waste into treasure. Therefore, new methods for N2O emission reduction are urgently needed. Among these, using N2O as a selective oxygen donor for the catalytic oxidation of hydrocarbons has attracted widespread attention from researchers. Numerous studies have found that N2O can non-catalytically oxidize olefins to produce carbon-based compounds. Panov.GI et al. introduced a highly efficient method for oxidizing olefins to carbon-based compounds, transferring oxygen from N2O to unsaturated carbon atoms with near 100% selectivity. This oxidation method can be applied to a variety of organic compounds, including aliphatic, cyclic, and heterocyclic olefins and their numerous derivatives.

[0006] Based on this, this project utilizes N2O to oxidize cyclohexane, an important chemical raw material, to synthesize cyclohexanone. Cyclohexanone is generally classified into two main categories according to its uses: amide-grade and non-amide-grade. Amide-grade cyclohexanone is mainly used to manufacture caprolactam and adipic acid, both of which are important raw materials for manufacturing fiber PA6 and engineering plastic PA66. Simultaneously, cyclohexanone is an important industrial solvent and can also be used in the production of pharmaceutical intermediates. Domestic cyclohexanone plants are mostly downstream caprolactam and adipic acid supporting facilities; its market as an organic solvent has not yet been fully developed. With the gradual maturation of the polyamide industry chain, more cyclohexanone production capacity will be released, and its application in high-end inks, additives, adhesives, and other fields will increase significantly. The main domestic manufacturers are as follows:

[0007]

[0008] Currently, the commonly used methods for synthesizing cyclohexanone are: ① phenol hydrogenation, ② cyclohexane oxidation, and ③ cyclohexene hydration. Among them, the phenol hydrogenation method mainly involves the catalytic hydrogenation of phenol under the action of hydrogen and a catalyst, as shown in reaction formula (4). Compared with other processes, the phenol hydrogenation method for producing cyclohexanone is safer, easier to separate and purify the product, and produces a better quality cyclohexanone. However, the main problems it faces are the design of the catalyst and the substitution of the hydrogen source. In addition, during the reaction, there is an intermediate active substance in the form of an enol before the conversion of phenol to cyclohexanone, resulting in the presence of cyclohexane, cyclohexanol, ethers, and alkane derivatives of phenol as byproducts, leading to a low yield of the target product, cyclohexanone.

[0009]

[0010] Another method is the cyclohexane oxidation process, as shown in (5). Cyclohexane is produced by hydrogenating benzene, and then cyclohexanone is obtained by oxidation. More than 90% of the cyclohexanone product is produced by this method. There are two oxidation process routes for cyclohexane oxidation: one is a catalytic oxidation process, and the other is a non-catalytic oxidation process. The catalytic oxidation process mainly uses cobalt salts, boric acid, or metaboric acid as catalysts. However, overall, this method has high energy consumption and high pollution, and with the continuous improvement of environmental awareness and requirements, it faces the need for improvement.

[0011]

[0012] Cyclohexene hydration is an important method for producing cyclohexanone, as shown in reaction formula (6). Benzene, as a substrate, is selectively hydrogenated under the action of a hydrogenation catalyst to prepare a cyclohexene intermediate. The intermediate can then be hydrated to efficiently produce cyclohexanol, which can be dehydrogenated to generate cyclohexanone. However, the process of preparing cyclohexanol via cyclohexene hydration is relatively cumbersome, with low single-pass conversion and high energy consumption, making it unsuitable for industrial production.

[0013]

[0014] Currently, there are two main caprolactam production processes in China: cyclohexane oxidation and cyclohexene hydration. As of the end of 2020, the total caprolactam production capacity in China was 4.37 million tons. Of this, the cyclohexene hydration process accounted for 2.31 million tons (53% of the total capacity), the cyclohexane oxidation process accounted for 1.66 million tons (38% of the total capacity), and the phenol process accounted for 400,000 tons (9% of the total capacity). New caprolactam projects under construction will add 3 million tons of capacity; except for the Baling Petrochemical relocation project, which plans to use the cyclohexene esterification process, all others will use the cyclohexene hydration process. Both methods involve the use of cyclohexanone as an intermediate.

[0015] (1) Cyclohexane oxidation method: using benzene and hydrogen as raw materials, benzene is hydrogenated to produce cyclohexane, cyclohexane is oxidized with air to produce a mixture of cyclohexanone and cyclohexanol (KA oil), and cyclohexanol is dehydrogenated to produce cyclohexanone.

[0016] (2) Cyclohexene hydration method: using benzene and hydrogen as raw materials, benzene is selectively hydrogenated to generate cyclohexene (byproduct cyclohexane), cyclohexene undergoes hydration reaction to generate cyclohexanol, and cyclohexanol undergoes dehydrogenation reaction to generate cyclohexanone.

[0017] (3) Nitrous oxide method: This project adopts the nitrous oxide oxidation of cyclohexene method, which generates cyclohexanone in one step with high selectivity.

[0018] (a) A comparison of the consumption quotas for the three methods is as follows:

[0019]

[0020] (b) Comparison of production costs and economic benefits

[0021]

[0022] Among the three processes for producing cyclohexanone, the nitrous oxide method has the lowest cost. In summary, the nitrous oxide method for producing cyclohexanone is highly competitive due to its rational process flow, low material consumption, ability to solve the air pollution problem caused by nitrous oxide, and low production cost.

[0023] In conclusion, the oxidation of cyclohexene with N₂O to produce cyclohexanone has significant practical implications. BASF has already built and put into operation a 30,000-ton-per-year cycloolefin oxidation production facility in Europe using this theory, although detailed process flow information has not been reported. Therefore, the use of N₂O to produce cyclohexanone, while bringing certain economic benefits, will also inevitably promote research on N₂O emission reduction and utilization, thereby meeting the needs of sustainable development. Transforming N₂O from an atmospheric pollutant into an important industrial raw material not only solves the environmental problems associated with N₂O but also provides a new technological route for the industrial production of cyclohexanone. Therefore, this research has significant social and economic value. Summary of the Invention

[0024] Purpose of the invention

[0025] To address the problems existing in the aforementioned technical processes, this invention provides an apparatus and method for producing cyclohexanone by oxidizing cyclohexene using waste gas from adipic acid production. This invention utilizes the waste gas from adipic acid production line, specifically the tail gas containing nitrous oxide emitted during the adipic acid production process, to oxidize cyclohexene and produce cyclohexanone.

[0026] Technical solution

[0027] Equipment and method for producing cyclohexanone by oxidizing cyclohexene using waste gas from adipic acid production. Method: Raw material gas A containing nitrous oxide from the adipic acid production line enters the raw material gas A storage tank. The raw material gas A storage tank is a floating head type gas tank with an operating pressure of 0.01–1.0 MPa and an operating temperature of 0–50°C. The raw material gas A from the storage tank enters a pressure swing adsorption (PSA) deoxygenation device to remove oxygen, reducing the oxygen content in the gas to less than 10 ppm. The qualified gas after oxygen removal by the PSA deoxygenation device is gas composition B. Gas composition B enters the raw material gas B storage tank. The raw material gas B storage tank is also a floating head type tank with an operating pressure of 0.01–1.0 MPa and an operating temperature of 0–50°C. Gas composition B is pressurized to 1.0–5.0 MPa and a temperature of 37–60°C by a first gas booster and then enters the raw material gas B metering tank.

[0028] An inert porous material is added inside the fixed-bed reactor. The gas constituting component B, originating from the feed gas B metering tank, is metered and pressurized to a pressure of 5–30 MPa, forming gas stream M1. Gas stream M1 is mixed with gas stream M3, a portion of which is returned from the high-pressure separator via a second gas booster. The standard state volume ratio of gas stream M1 to gas stream M3 is controlled at 1:1–1:50. This mixture then enters a high-pressure heat exchanger to exchange heat with the reaction product stream M4 from the fixed-bed reactor packed with inert porous material. After heat exchange, the temperature of the M1–M3 mixture reaches 90–200°C. It then enters a high-pressure preheater to be preheated to 210–350°C. After preheating, the gas stream M1–M3 mixture enters the fixed-bed reactor packed with inert porous material. Cyclohexene or cyclohexene-saturated... The alkane mixture stream M2 originates from a cyclohexene metering tank. After pressurization and metering, it enters a high-pressure heat exchanger to exchange heat with the reaction product stream M4 from a fixed-bed reactor packed with inert porous material. After heat exchange, the temperature reaches 90–200°C. It then enters a high-pressure preheater for preheating, reaching the required temperature of 100–350°C for the fixed-bed reactor. The cyclohexene reacts with the feed gas B in the fixed-bed reactor to produce the target product, cyclohexanone. The cyclohexene or a mixture of cyclohexene and saturated alkanes is continuously fed into the fixed-bed reactor along with the feed gas B via the high-pressure heat exchanger and preheater. The molar ratio of nitrous oxide in cyclohexene and feed gas B is 1:0.05–1:1.0, and the following reaction occurs:

[0029] C n H 2n-2 (Cyclohexene) + N₂O (nitrous oxide) → C n H 2n-2 O (product cyclohexanone) + N2↑ (nitrogen gas) where: n is a positive integer of 6;

[0030] The reaction temperature in the fixed-bed reactor is controlled at 100–350℃, and the pressure in the fixed-bed reactor is 5–30 MPa. The main target product, cyclohexanone, is generated. The selectivity of cyclohexene to cyclohexanone is greater than 98.0%, and the conversion rate of nitrous oxide in feed gas B is greater than or equal to 99.9%.

[0031] The inlet stream of the high-pressure separator is called M6. Part of the gas phase is mixed with the gas stream M1 by the stream M3 compressed and returned by the second gas booster of the circulation system. Part of the stream is called M8 and enters the cryogenic gas discharge tank. In the cryogenic gas discharge tank, the liquid phase enters the low-pressure separator for recycling. The gas phase is called gas stream M9. After testing, the N2O content is less than 0.1% of the total volume and is qualified before being discharged.

[0032] The liquid phase from the high-pressure separator enters the low-pressure separator. The liquid phase in the low-pressure separator consists of cyclohexanone product and unreacted cyclohexene, or a mixture of cyclohexanone product, unreacted cyclohexene, and saturated alkanes, referred to as stream M7. Stream M7 undergoes qualitative analysis by chromatographic mass spectrometry and quantitative analysis by chromatographic chromatography. The target product, cyclohexanone, is obtained by distillation, and unreacted cyclohexene is obtained by further distillation. The mixture of cyclohexene and saturated alkanes is recycled.

[0033] Equipment: Includes a nitrogen tank, a cyclohexene metering tank, a feed gas B metering tank, a high-pressure heat exchanger, a high-pressure preheater, a fixed-bed reactor, a high-pressure cooler, a high-pressure separator, a cryogenic gas exhaust tank, and a low-pressure separator. The cyclohexene metering tank has a cyclohexene inlet. Its outlet is connected to the inlet of the fixed-bed reactor via a pipeline through the high-pressure heat exchanger and preheater. Similarly, the outlet of the feed gas B metering tank is connected to the inlet of the fixed-bed reactor via a pipeline through the high-pressure heat exchanger and preheater. The outlet of the fixed-bed reactor is connected to the inlet of the high-pressure separator via a pipeline through the high-pressure heat exchanger and preheater. The outlet at the top of the high-pressure separator is connected to the inlet of the cryogenic gas exhaust tank via a pipeline. The cryogenic gas exhaust tank has a nitrogen exhaust port at its top. The outlet at the bottom of the high-pressure separator is connected to the inlet of the low-pressure separator via a pipeline. The low-pressure separator has a product collection port at its bottom and a gas exhaust port at its top. (The equipment also includes a cyclohexene metering tank, a feed gas B metering tank, a high-pressure heat exchanger, and a high-pressure preheater.) The apparatus includes a fixed-bed reactor, a high-pressure cooler, a high-pressure separator, a cryogenic gas discharge tank, and a low-pressure separator, all connected to a nitrogen tank via pipelines. The nitrogen tank is equipped with a nitrogen inlet. It also includes a raw material gas A storage tank, a pressure swing adsorption (PSA) deoxygenation unit, a raw material gas B storage tank, a first gas booster, and a second gas booster. The raw material gas A storage tank has an adipic acid raw material gas inlet. The outlet of the raw material gas A storage tank is connected to the inlet of the PSA deoxygenation unit via a pipeline. The outlet of the PSA deoxygenation unit is connected to the inlet of the raw material gas B storage tank via a pipeline. The outlet of the raw material gas B storage tank is connected to the inlet of the first gas booster via a pipeline. The raw material gas B metering tank has a raw material gas B inlet. The outlet of the first gas booster is connected to the raw material gas B inlet of the raw material gas B metering tank via a pipeline. The outlet of the high-pressure separator, before entering the cryogenic gas discharge tank, is connected to the inlet of the second gas booster. The outlet of the cyclohexene metering tank, before entering the high-pressure heat exchanger, is connected to the outlet of the second gas booster via a pipeline.

[0034] Furthermore, the bottom of the cyclohexene metering tank, the raw material gas B metering tank, the high-pressure heat exchanger, the high-pressure preheater, the fixed-bed reactor, the high-pressure cooler, the high-pressure separator, the cryogenic gas discharge tank, and the low-pressure separator are provided with low-pressure discharge ports.

[0035] Furthermore, the outlet pipe of the cyclohexene metering tank is equipped with a cyclohexene metering booster pump, the outlet pipe of the raw material gas B metering tank is equipped with a nitrous oxide metering booster pump, the outlet pipe of the fixed bed reactor is equipped with a high-pressure filter, and the inlet pipe of the fixed bed reactor is also connected to the nitrogen tank.

[0036] Furthermore, after adding inert porous material inside the fixed-bed reactor, the entire equipment needs to be purged with N2 gas from a nitrogen tank before the reaction begins. The subsequent reaction is carried out under N2 protection. After mixing gases M1 and M3, the temperature reaches 90-200℃ after passing through a high-pressure heat exchanger, and then reaches 210-350℃ after passing through a high-pressure preheater. The reaction temperature inside the fixed-bed reactor is controlled at 100-350℃, and the pressure inside the fixed-bed reactor is 5-30MPa. The material entering the high-pressure cooler is cooled to 0-35℃ by the high-pressure cooler.

[0037] Furthermore, the fixed-bed reactor is equipped with a cage-type heat exchanger. The cage-type heat exchanger is of the type specified in Chinese Patent Publication No. CN209197530U, entitled "A Cage-Type Heat Exchanger in a Catalytic Hydrogenation Reactor." A heat carrier at 100-350°C is introduced into the cage-type heat exchanger in the catalytic hydrogenation reactor to remove the heat released during the reaction of cyclohexene and nitrous oxide. An inert porous material is added to the inner cavity of the fixed-bed reactor. The fixed-bed reactor is a tubular fixed-bed reactor with a jacket layer. A heat carrier at 100-350°C passes through the jacket to remove the heat released during the reaction of cyclohexene and nitrous oxide. The tubular fixed-bed reactor is a single-tube or multi-tube parallel fixed-bed reactor. Furthermore, the inert porous material is one or more of porous ceramics, porous glass, or porous alumina. The inert porous material has a cylindrical or spherical structure. The cylindrical shape has dimensions of φ5mm × 5mm to φ20mm × 20mm, and the spherical shape has a radius R of 5mm to 20mm. The inert porous material has a specific surface area of ​​30 to 260 m². 2 / g, pore size 5~300nm, compressive strength >150kgf / cm 2 .

[0038] Furthermore, the inert porous material has a specific surface area of ​​30–170 m². 2 / g, pore size 5~230nm.

[0039] Furthermore, the fixed-bed reactor is a vertical reactor. Cyclohexene is injected all at once from the top of the fixed-bed reactor. Nitrous oxide gas streams M1 and M3 are injected all at once from the top of the fixed-bed reactor, or nitrous oxide gas streams M1 and M3 are injected into the fixed-bed reactor in three parts from the top, middle, and bottom. The top feed position refers to 0.0% to 20% of the feed volume from the top of the fixed-bed reactor, the middle feed position refers to 20% to 40% of the feed volume from the top of the fixed-bed reactor, and the bottom feed position refers to 40% to 70% of the feed volume from the top of the fixed-bed reactor. The proportion of nitrous oxide feed in the three parts accounts for 20% to 40% of the total nitrous oxide feed volume, respectively. Alternatively, nitrous oxide gas streams M1 and M3 are injected evenly from the top of the fixed-bed reactor at positions ranging from 0.0% to 70%.

[0040] Furthermore, in the cyclohexene-saturated alkane mixture, the mol ratio of cyclohexene to saturated alkane is 1:1 to 1:20, and the saturated alkane refers to straight-chain alkanes, branched alkanes, or cycloalkanes from C4 to C20.

[0041] Advantages and effects

[0042] The waste gas containing nitrous oxide from the nitrous oxide production line only undergoes oxygen removal treatment. Other gases it contains do not need to be separated and directly enter a fixed-bed reactor filled with inert porous material. The fixed-bed reactor is equipped with a cage heat exchanger (CN209197530U). The nitrous oxide in the mixed gas reacts with cyclohexene in the fixed-bed reactor to generate the highly selective target product cyclohexanone.

[0043] Secondly, the gas section of the high-pressure separator in this process unit adopts a certain proportion of reflux. The refluxed gas is mixed with the raw material gas B, which increases the inert gas content in the reactor, enhances the mass and heat transfer effect in the fixed bed reactor, and makes the operation of the fixed bed reactor more stable. Attached Figure Description

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.

[0045] Figure 1This is a schematic diagram of the equipment connection structure for producing cyclohexanone by oxidizing cyclohexene using waste gas from adipic acid production; Reference numerals: E101. High-pressure heat exchanger, E102. High-pressure preheater, F101. High-pressure filter, K101. Fixed-bed reactor, P101. Cyclohexene metering booster pump, P102. Nitrous oxide metering booster pump, R101. Cyclohexene metering tank, R102. Raw material gas B metering tank, R103. High-pressure cooler, R104. High-pressure separator, R105. Cryogenic gas exhaust tank, R106. Low-pressure separator, V101. Nitrogen tank, T101. Raw material gas A storage tank, U101. Pressure swing adsorption deoxygenation device, T102. Raw material gas B storage tank, H101. First gas booster, H201. Second gas booster. Detailed Implementation

[0046] like Figure 1 As shown in the figure, L represents a level gauge, T represents a temperature transmitter, and P represents a pressure transmitter.

[0047] Equipment and methods for producing cyclohexanone by oxidizing cyclohexene using waste gas from adipic acid production:

[0048] Method: Nitrous oxide-containing raw material gas A from the oxalic acid production line enters raw material gas storage tank T101. Tank T101 is a floating head type gas storage tank. The operating pressure of tank T101 is 0.01–1.0 MPa, and the operating temperature is 0–50°C. Raw material gas A from tank T101 then enters a pressure swing adsorption (PSA) deoxygenation unit U101 to remove oxygen, reducing the oxygen content in the gas to less than 10 ppm. The gas that has been deoxygenated by the deoxygenation device U101 is gas composition B. Gas composition B enters the raw material gas B storage tank T102. The raw material gas B storage tank T102 is a floating head tank. The operating pressure of the raw material gas B storage tank T102 is 0.01~1.0Mpa, and the operating temperature is 0~50℃. Gas composition B is pressurized to 1.0~5.0Mpa and 37~60℃ by the first gas booster H101 and then enters the raw material gas B metering tank R102.

[0049] An inert porous material is added inside the fixed-bed reactor K101. The gas constituting B from the feed gas metering tank R102 is metered and pressurized to a pressure of 5-30 MPa, forming gas stream M1. Gas stream M1 is mixed with gas stream M3, which is partially transported back from the high-pressure separator R104 via the second gas booster H201. The standard state volume ratio of gas stream M1 to gas stream M3 is controlled at 1:1 to 1:50. Then, it enters the high-pressure heat exchanger E101 and mixes with the gas from the packing material. The reaction product stream M4 in the fixed-bed reactor K101, which is filled with inert porous material, undergoes heat exchange. After heat exchange, the temperature of the mixture stream of M1 and M3 reaches 90-200℃, and then it enters the high-pressure preheater E102 for preheating to 210-350℃. After preheating, the mixture stream of gaseous streams M1 and M3 enters the fixed-bed reactor K101 filled with inert porous material. The cyclohexene or cyclohexene-saturated alkane mixture stream M2 comes from the cyclohexene metering tank R101. In this process, the molar ratio of cyclohexene to saturated alkanes is 1:1 to 1:20. Saturated alkanes refer to straight-chain alkanes, branched alkanes, or cycloalkanes from C4 to C20. After pressurization and metering, the product stream M4 from the fixed-bed reactor K101, packed with inert porous material, undergoes heat exchange in the high-pressure heat exchanger E101. After heat exchange, the temperature reaches 90–200°C. Then, it enters the high-pressure preheater E102 for preheating, reaching the temperature required by the fixed-bed reactor K101, which is 100–350°C. At ℃, cyclohexene enters a fixed-bed reactor K101 filled with inert porous material. Cyclohexene reacts with feed gas B within the fixed-bed reactor K101 to produce the target product, cyclohexanone. The mixture of cyclohexene or cyclohexene and saturated alkanes is continuously fed into the fixed-bed reactor K101 via a high-pressure heat exchanger E101 and a high-pressure preheater E102. The molar ratio of cyclohexene to nitrous oxide in feed gas B is 1:0.05 to 1:1.0, and the following reaction occurs:

[0050] C n H 2n-2 (Cyclohexene) + N₂O (nitrous oxide) → C n H 2n-2 O (product cyclohexanone) + N2↑ (nitrogen gas) where: n is a positive integer of 6;

[0051] The reaction temperature in the fixed-bed reactor K101 is controlled at 100–350℃, and the pressure in the fixed-bed reactor K101 is 5–30 MPa. The main target product, cyclohexanone, is generated, with a selectivity of cyclohexene to cyclohexanone greater than 98.0%. The conversion rate of nitrous oxide in the feed gas B is greater than or equal to 99.9%. The inlet stream of the high-pressure separator R104 is called M6. Part of the gas phase is mixed with the gas stream M1 by the compressed and returned stream M3 from the second gas booster H201. The other part is called M8 and enters the cryogenic gas discharge tank R105. In the cryogenic gas discharge tank R105, the liquid phase enters the low-pressure separator R106 for recycling, and the gas phase is called gas stream M9. After testing, the N2O content is less than 0.1% of the total volume and is qualified before being discharged.

[0052] The liquid phase in high-pressure separator R104 enters low-pressure separator R106. The liquid phase in low-pressure separator R106 consists of cyclohexanone product and unreacted cyclohexene, or a mixture of cyclohexanone product, unreacted cyclohexene, and saturated alkanes, referred to as stream M7. Stream M7 undergoes qualitative analysis by chromatographic mass spectrometry and quantitative analysis by chromatographic chromatography. The target product, cyclohexanone, is obtained by distillation, and unreacted cyclohexene is obtained by further distillation. The mixture of cyclohexene and saturated alkanes is recycled.

[0053] Equipment includes a nitrogen tank V101, a cyclohexene metering tank R101, a feed gas B metering tank R102, a high-pressure heat exchanger E101, a high-pressure preheater E102, a fixed-bed reactor K101, a high-pressure cooler R103, a high-pressure separator R104, a cryogenic gas exhaust tank R105, and a low-pressure separator R106. The cyclohexene metering tank R101 has a cyclohexene inlet. The outlet of the cyclohexene metering tank R101 is connected to the inlet of the fixed-bed reactor K101 via a pipeline through the high-pressure heat exchanger E101 and the high-pressure preheater E102. The outlet of the feed gas B metering tank R102 is connected to the fixed bed reactor K101 via a pipeline through the high-pressure heat exchanger E101 and the high-pressure preheater E102. The inlet of reactor K101 and the outlet of fixed-bed reactor K101 are connected to the inlet of high-pressure separator R104 via pipelines through high-pressure heat exchanger E101 and high-pressure cooler R103. The outlet at the upper end of high-pressure separator R104 is connected to the inlet of cryogenic gas exhaust tank R105 via pipelines. A nitrogen exhaust port is located at the upper end of cryogenic gas exhaust tank R105. The outlet at the lower end of high-pressure separator R104 is connected to the inlet of low-pressure separator R106 via pipelines. A product collection port is located at the lower end of low-pressure separator R106, and a gas exhaust port is located at the upper end of low-pressure separator R106. Cyclohexene metering tank R101, raw material gas B metering tank R102, and high-pressure heat exchanger E104 are also present. 101. The high-pressure preheater E102, fixed-bed reactor K101, high-pressure cooler R103, high-pressure separator R104, cryogenic gas exhaust tank R105, and low-pressure separator R106 are all connected to nitrogen tank V101 via pipelines. Nitrogen tank V101 is equipped with a nitrogen inlet. The system also includes a feed gas A storage tank T101, a pressure swing adsorption (PSA) deoxygenation device U101, a feed gas B storage tank T102, a first gas booster H101, and a second gas booster H201. Feed gas A storage tank T101 is equipped with an adipic acid feed gas inlet. The outlet of feed gas A storage tank T101 is connected to the inlet of the PSA deoxygenation device U101 via a pipeline. The pressure swing adsorption (PSA) deoxygenation device U101... The outlet of gas 1 is connected to the inlet of raw material gas storage tank T102 via a pipeline. The outlet of raw material gas storage tank T102 is connected to the inlet of the first gas booster H101 via a pipeline. Raw material gas metering tank R102 is provided with raw material gas inlet. The outlet of the first gas booster H101 is connected to the raw material gas inlet of raw material gas metering tank R102 via a pipeline. The outlet of high-pressure separator R104 is connected to the inlet of second gas booster H201 via a pipeline that does not enter cryogenic gas discharge tank R105. The outlet of cyclohexene metering tank R101 is connected to the outlet of second gas booster H201 via a pipeline that does not enter high-pressure heat exchanger E101.

[0054] The bottom of the cyclohexene metering tank R101, the raw material gas B metering tank R102, the high-pressure heat exchanger E101, the high-pressure preheater E102, the fixed bed reactor K101, the high-pressure cooler R103, the high-pressure separator R104, the cryogenic gas discharge tank R105, and the low-pressure separator R106 are equipped with low discharge ports.

[0055] The outlet pipe of the cyclohexene metering tank R101 is equipped with a cyclohexene metering booster pump P101, the outlet pipe of the raw material gas B metering tank R102 is equipped with a nitrous oxide metering booster pump P102, the outlet pipe of the fixed bed reactor K101 is equipped with a high-pressure filter F101, and the inlet pipe of the fixed bed reactor K101 is also connected to the nitrogen tank V101.

[0056] After adding inert porous material inside the fixed-bed reactor K101, the entire equipment needs to be purged with N2 gas from nitrogen tank V101 before the reaction begins. The subsequent reaction is carried out under N2 protection. After mixing gases M1 and M3, the mixture passes through high-pressure heat exchanger E101, where the temperature reaches 90-200℃. After passing through high-pressure preheater E102, the temperature reaches 210-350℃. The reaction temperature inside the fixed-bed reactor K101 is controlled at 100-350℃. The pressure inside the fixed-bed reactor K101 is maintained at 5-30MPa. The material R103 entering the high-pressure cooler is cooled to 0-35℃ by the high-pressure cooler R103.

[0057] The fixed-bed reactor K101 is equipped with a cage-type heat exchanger. The model of the cage-type heat exchanger is Chinese Patent Publication No.: CN209197530U, patent name: A cage-type heat exchanger in a catalytic hydrogenation reactor. A heat carrier at 100-350°C is introduced into the cage-type heat exchanger in the catalytic hydrogenation reactor to remove the heat released during the reaction of cyclohexene and nitrous oxide. An inert porous material is added to the inner cavity of the fixed-bed reactor. The fixed-bed reactor is a tubular fixed-bed reactor with a jacket layer. A heat carrier at 100-350°C passes through the jacket to remove the heat released during the reaction of cyclohexene and nitrous oxide. The tubular fixed-bed reactor is a single-tube or multi-tube parallel fixed-bed reactor.

[0058] Inert porous materials are one or more of porous ceramics, porous glass, or porous alumina. The structure of these materials is cylindrical or spherical. Cylindrical materials have dimensions of φ5mm × 5mm to φ20mm × 20mm, while spherical materials have a radius R of 5mm to 20mm. These inert porous materials have a specific surface area of ​​30 to 260 m². 2 / g, pore size 5~300nm, compressive strength >150kgf / cm 2 Inert porous materials have a specific surface area of ​​30–170 m². 2 / g, pore size 5~230nm.

[0059] The fixed-bed reactor K101 is a vertical reactor. Cyclohexene is injected into the fixed-bed reactor K101 in a single injection from the top. Nitrous oxide gas streams M1 and M3 are injected into the fixed-bed reactor K101 in a single injection from the top, or in three separate injection points (top, middle, and bottom) from the top, middle, and bottom of the fixed-bed reactor K101. The top feed point refers to the 0° position from the top of the fixed-bed reactor K101 downwards. The feed positions are 0% to 20%, the middle feed position refers to the position from the top of the fixed bed reactor K101 from 20% to 40% from top to bottom, and the lower feed position refers to the position from the top of the fixed bed reactor K101 from 40% to 70% from top to bottom. The proportion of nitrous oxide feed in the three positions is 20% to 40% of the total nitrous oxide feed, respectively. Alternatively, gaseous streams M1 and M3 containing nitrous oxide are uniformly injected from the top of the fixed bed reactor K101 from 0.0% to 70%.

[0060] In summary:

[0061] First, this invention uses an inert porous material, based on the Kelvin equation.

[0062]

[0063] Where P 凹 The saturated vapor pressure of the inert porous membrane.

[0064] P 0 The saturated vapor pressure representing the vapor in the liquid plane state;

[0065] r 凹 The radius representing the pore size of an inert porous material;

[0066] T represents thermodynamic temperature;

[0067] M represents the molecular weight of cyclohexene;

[0068] R represents a thermodynamic constant.

[0069]

[0070] σ can be viewed as the value of free enthalpy per unit surface area at a specified temperature and pressure, also known as surface free enthalpy.

[0071] ρ represents the density of the liquid;

[0072] n j It represents the composition of the liquid.

[0073] As can be seen from Formula 1, the inert porous material r 凹 The smaller the value, the better for the same T and n. j Under the condition, P 凹 <P 0 This forms a liquid film; in other words, the presence of inert porous materials reduces the reaction pressure between cyclohexene and nitrous oxide.

[0074] Second, the inert porous material allows cyclohexene to be adsorbed on its surface, forming a liquid film with a large surface area. This provides sufficient opportunity for nitrous oxide and cyclohexene to collide and react to form cyclohexanone. The presence of the porous material gives the cyclohexene liquid film a large surface activation energy, which provides sufficient activation energy for the reaction between cyclohexene and nitrous oxide.

[0075] Third, inert porous materials have a large specific surface area, which can remove the branched free radicals generated during the reaction of cyclohexene and nitrous oxide, thus preventing the occurrence of an explosive reaction.

[0076] Combining the above three advantages, the monopolymer conversion rate of the reaction between cyclohexene and nitrous oxide is higher than the conventional level of existing technologies.

[0077] Material unit conversion rate definition:

[0078] Material conversion rate (%) is defined as (AB) / A*100%.

[0079] A: Under stable operating conditions of a fixed-bed reactor, the temperature, pressure, flow rate, and composition of each bed in the fixed-bed reactor have constant values ​​per unit time. The number of mol of cyclohexene entering from the inlet of the fixed-bed reactor per unit time is A, and the number of mol of cyclohexene that has not participated in the reaction at the outlet of the fixed-bed reactor is B.

[0080] The number of mol of the target compound cyclohexanone generated at the outlet of the fixed-bed reactor is C.

[0081] Selective definition:

[0082] The selectivity (%) for generating the target compound cyclohexanone = C / (AB)*100%.

[0083] Table 1: Gas composition of mixed gas A containing nitrous oxide emitted during the oxidation of nitric acid to produce adipic acid.

[0084]

[0085]

[0086] Table 2: Gas composition of gas mixture B

[0087] Gas composition Content, %V / V <![CDATA[N2O]]> 36.65～44.68 <![CDATA[N2]]> 47.12～53.19 <![CDATA[NO X ]]> 0.021～0.043 <![CDATA[O2]]> Less than or equal to 10 ppm CO 0.16～0.32 <![CDATA[CO2]]> 5.86～6.70 Moisture 1.88～2.66

[0088] The composition of raw material gas A is shown in Table 1. The source of raw material gas A is limited by the unstable production process of the adipic acid production line; its composition varies with hourly flow rate, pressure, and temperature. Raw material gas A is stored in raw material gas A storage tank T101, where it undergoes mixing and balancing to stabilize the process. After stabilization, the raw material gas A, with its temperature, pressure, and flow rate, is deoxygenated by the pressure swing adsorption deoxygenation unit U101. The composition of the raw material gas B supplied to the first gas booster H101 is shown in Table 2.

[0089] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all embodiments here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. Process for the oxidation of cyclohexene with adipic acid production off-gas to produce cyclohexanone, characterized in that: The feed gas A, containing nitrous oxide, from the oxalic acid production line enters the feed gas A storage tank (T101). The feed gas A storage tank (T101) is a floating head type gas storage tank. The operating pressure of the feed gas A storage tank (T101) is 0.01–1.0 MPa, and the operating temperature is 0–50℃. The feed gas A from the feed gas A storage tank (T101) enters the pressure swing adsorption (PSA) deoxygenation unit (U101) to remove oxygen, reducing the oxygen content in the gas to less than 10 ppm. After PSA deoxygenation... The oxygen unit (U101) removes qualified oxygen to produce gas composition B. Gas composition B enters the raw material gas B storage tank (T102). The raw material gas B storage tank (T102) is a floating head type tank. The operating pressure of the raw material gas B storage tank (T102) is 0.01~1.0MPa, and the operating temperature is 0~50℃. Gas composition B is pressurized to 1.0~5.0MPa and 37~60℃ by the first gas booster (H101) and then enters the raw material gas B metering tank (R102). An inert porous material is added inside the fixed-bed reactor (K101). The gas constituting B from the feed gas metering tank (R102) is metered and pressurized to a pressure of 5–30 MPa, forming gas stream M1. Gas stream M1 is mixed with gas stream M3, part of the gas from the high-pressure separator (R104) and partially returned by the second gas booster (H201). The standard state volume ratio of gas stream M1 to gas stream M3 is controlled at 1:1 to 1:50, and then the mixture enters the high-pressure reactor. The high-pressure heat exchanger (E101) exchanges heat with the reaction product stream M4 from the fixed-bed reactor (K101) packed with inert porous material. After heat exchange, the temperature of the mixture of gas streams M1 and M3 reaches 90–200°C, and then it enters the high-pressure preheater (E102) for preheating to 210–350°C. After preheating, the mixture of gas streams M1 and M3 enters the fixed-bed reactor (K101) packed with inert porous material, containing cyclohexene or cyclohexene-saturated alkane. Hydrocarbon mixture stream M2 originates from the cyclohexene metering tank (R101). After pressurization and metering, it enters the high-pressure heat exchanger (E101) to exchange heat with the reaction product stream M4 from the fixed-bed reactor (K101) packed with inert porous material. After heat exchange, the temperature reaches 90–200°C. It then enters the high-pressure preheater (E102) for preheating, reaching the temperature required by the fixed-bed reactor (K101) of 100–350°C before entering the fixed-bed reactor packed with inert porous material. In a fixed-bed reactor (K101), cyclohexene reacts with feed gas B within a fixed-bed reactor (K101) packed with inert porous material to produce the target product cyclohexanone. The cyclohexene, or a mixture of cyclohexene and saturated alkanes, is continuously fed into the fixed-bed reactor (K101) along with feed gas B via a high-pressure heat exchanger (E101) and a high-pressure preheater (E102). The molar ratio of cyclohexene to nitrous oxide in feed gas B is 1:0.05 to 1:1.0, and the following reaction occurs: C6H 10 (Cyclohexene) + N₂O (nitrous oxide) → C₆H₂O 10 O (product cyclohexanone) + N2↑ (nitrogen gas); The reaction temperature in the fixed-bed reactor (K101) is controlled at 100-350℃, and the pressure in the fixed-bed reactor (K101) is 5-30MPa. The main target product, cyclohexanone, is generated. The selectivity of cyclohexene to cyclohexanone is greater than 98.0%, and the conversion rate of nitrous oxide in feed gas B is greater than or equal to 99.9%. The inlet stream of the high-pressure separator (R104) is called M6. Part of the gas phase is mixed with gas stream M3, which is compressed and returned by the second circulating gas booster (H201), and part of the stream is called M8. It enters the cryogenic gas discharge tank (R105). In the cryogenic gas discharge tank (R105), the liquid phase enters the low-pressure separator (R106) for recycling. The gas phase is called gas stream M9. After testing, the N2O content is less than 0.1% of the total volume and is qualified, it is discharged. The liquid phase in the high-pressure separator (R104) enters the low-pressure separator (R106). The liquid phase in the low-pressure separator (R106) consists of cyclohexanone product and unreacted cyclohexene, or a mixture of cyclohexanone product, unreacted cyclohexene, and saturated alkanes, referred to as stream M7. Stream M7 undergoes qualitative analysis by chromatographic mass spectrometry and quantitative analysis by chromatographic chromatography. The target product, cyclohexanone, is obtained by distillation, and unreacted cyclohexene is obtained by further distillation. The mixture of cyclohexene and saturated alkanes is recycled.

2. The method according to claim 1, characterized in that: After adding inert porous material inside the fixed-bed reactor (K101), the entire equipment needs to be purged with N2 gas from the nitrogen tank (V101) before the reaction begins. The subsequent reaction is carried out under N2 protection. After the gas streams M1 and M3 are mixed, the temperature reaches 90-200℃ after passing through the high-pressure heat exchanger (E101), and then reaches 210-350℃ after passing through the high-pressure preheater (E102). The reaction temperature in the fixed-bed reactor (K101) is controlled at 100-350℃. The pressure in the fixed-bed reactor (K101) is 5-30MPa. The material entering the high-pressure cooler (R103) is cooled to 0-35℃.

3. The method according to claim 1, characterized in that: The inert porous material is one or more of porous ceramics, porous glass, or porous alumina. The inert porous material has a cylindrical or spherical structure. The cylindrical shape has dimensions of φ5mm × 5mm to φ20mm × 20mm, and the spherical shape has a radius R of 5mm to 20mm. The inert porous material has a specific surface area of ​​30 to 260 m². 2 / g, pore size 5~300nm, compressive strength >150kgf / cm 2 .

4. The method according to claim 3, characterized in that: The inert porous material has a specific surface area of ​​30–170 m². 2 / g, pore size 5~230nm.

5. The method according to claim 1, characterized in that: The fixed-bed reactor (K101) is a vertical reactor. Cyclohexene is injected into the fixed-bed reactor (K101) all at once from the top. Nitrous oxide gas streams M1 and M3 are also injected into the fixed-bed reactor (K101) all at once from the top, or the nitrous oxide gas streams M1 and M3 are injected into the fixed-bed reactor (K101) in three parts from the top, middle, and bottom. The top feed position refers to the feed starting from the top of the fixed-bed reactor (K101). The feed amounts of nitrous oxide are 0.0% to 20% from the bottom, the middle feed position refers to 20% to 40% from the top of the fixed bed reactor (K101), and the lower feed position refers to 40% to 70% from the top of the fixed bed reactor (K101). The proportion of nitrous oxide feed amounts in these three positions is 20% to 40% of the total nitrous oxide feed amount, respectively. Alternatively, gaseous streams M1 and M3 containing nitrous oxide are uniformly injected from the top of the fixed bed reactor (K101) at positions ranging from 0.0% to 70%.

6. The method of claim 1, wherein: In the cyclohexene-saturated alkane mixture, the mol ratio of cyclohexene to saturated alkane is 1:1 to 1:20, and the saturated alkane refers to straight-chain alkanes, branched alkanes, or cycloalkanes from C4 to C20.

7. An apparatus for use in a process for the oxidation of cyclohexene to cyclohexanone using an adipic acid production off-gas according to claim 1, characterized in that: The reactor includes a nitrogen tank (V101), a cyclohexene metering tank (R101), a feed gas B metering tank (R102), a high-pressure heat exchanger (E101), a high-pressure preheater (E102), a fixed-bed reactor (K101), a high-pressure cooler (R103), a high-pressure separator (R104), a cryogenic gas exhaust tank (R105), and a low-pressure separator (R106). The cyclohexene metering tank (R101) has a cyclohexene inlet. The outlet of the cyclohexene metering tank (R101) is connected to the inlet of the fixed-bed reactor (K101) via a pipeline through the high-pressure heat exchanger (E101) and the high-pressure preheater (E102). The outlet of the feed gas B metering tank (R102) is connected to... The pipeline connects to the inlet of the fixed-bed reactor (K101) via a high-pressure heat exchanger (E101) and a high-pressure preheater (E102). The outlet of the fixed-bed reactor (K101) connects to the inlet of the high-pressure separator (R104) via a pipeline through the high-pressure heat exchanger (E101) and a high-pressure cooler (R103). The outlet at the upper end of the high-pressure separator (R104) connects to the inlet of a cryogenic gas exhaust tank (R105), which has a nitrogen exhaust port at its upper end. The outlet at the lower end of the high-pressure separator (R104) connects to the inlet of a low-pressure separator (R106) via a pipeline. The lower end of the low-pressure separator (R106) has a nitrogen exhaust port. The product collection port and the upper end of the low-pressure separator (R106) are equipped with gas exhaust ports; the cyclohexene metering tank (R101), raw material gas B metering tank (R102), high-pressure heat exchanger (E101), high-pressure preheater (E102), fixed-bed reactor (K101), high-pressure cooler (R103), high-pressure separator (R104), cryogenic gas exhaust tank (R105), and low-pressure separator (R106) are all connected to the nitrogen tank (V101) through pipelines, and the nitrogen tank (V101) is equipped with a nitrogen inlet; it also includes a raw material gas A storage tank (T101), a pressure swing adsorption deoxygenation device (U101), a raw material gas B storage tank (T102), and a first gas pressurization unit. The unit consists of a gas compressor (H101) and a second gas booster (H201). The raw material gas A storage tank (T101) is equipped with an adipic acid raw material gas inlet. The outlet of the raw material gas A storage tank (T101) is connected to the inlet of the pressure swing adsorption deoxygenation device (U101) via a pipeline. The outlet of the pressure swing adsorption deoxygenation device (U101) is connected to the inlet of the raw material gas B storage tank (T102) via a pipeline. The outlet of the raw material gas B storage tank (T102) is connected to the inlet of the first gas booster (H101) via a pipeline. The raw material gas B metering tank (R102) is equipped with a raw material gas B inlet. The outlet of the first gas booster (H101) is connected to the raw material gas B inlet of the raw material gas B metering tank (R102) via a pipeline.The outlet of the high-pressure separator (R104), before entering the cryogenic gas discharge tank (R105), is connected to the inlet of the second gas booster (H201). The outlet of the cyclohexene metering tank (R101), before entering the high-pressure heat exchanger (E101), is connected to the outlet of the second gas booster (H201).

8. The apparatus of claim 7, wherein: The bottom of the cyclohexene metering tank (R101), the raw material gas B metering tank (R102), the high-pressure heat exchanger (E101), the high-pressure preheater (E102), the fixed bed reactor (K101), the high-pressure cooler (R103), the high-pressure separator (R104), the cryogenic gas discharge tank (R105), and the low-pressure separator (R106) are provided with low-pressure discharge ports.

9. The apparatus of claim 7, wherein: The outlet pipe of the cyclohexene metering tank (R101) is equipped with a cyclohexene metering booster pump (P101), the outlet pipe of the raw material gas B metering tank (R102) is equipped with a nitrous oxide metering booster pump (P102), the outlet pipe of the fixed bed reactor (K101) is equipped with a high-pressure filter (F101), and the inlet pipe of the fixed bed reactor (K101) is also connected to the nitrogen tank (V101).

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