A method, system and application for propane oxidation to propylene using a microchannel reactor

Abstract

This invention belongs to the field of propylene preparation, and relates to a method, system, and application for the oxidation of propane to propylene using a microchannel reactor. The method includes a mixing reaction of propane and oxygen in a microchannel reactor in the presence of an acid solution to obtain propylene. The microchannel reactor is made of a catalyst material used for the catalytic oxidation of propane to propylene, and the copper content in the catalyst material is above 97 wt%. This invention conducts the reaction within a microchannel reactor made of a catalyst, avoiding the problem of catalyst loading. Because the gas is separated into small bubbles by segments of acid solution within the microchannel reactor, the problem of easy explosion during propane oxidation is solved. By utilizing the efficient mass and heat transfer characteristics of the microreactor, high conversion of propane and high selectivity of propylene are achieved at room temperature or near room temperature.

Description

Technical Field

[0001] This invention belongs to the field of propylene preparation, and relates to a method, system and application of propylene production by propane oxidation using a microchannel reactor. Background Technology

[0002] In recent years, with the development of shale gas, my country's propane production has further increased. However, currently, my country mostly utilizes propane for energy through combustion, resulting in low utilization value. Converting propane into high-value-added products is one of the key technologies for improving propane utilization efficiency and achieving efficient utilization of carbon-based energy, with broad practical prospects and significant economic benefits. Among propane's downstream products, propylene is a very important chemical raw material, which can be used to produce high-value-added products such as polypropylene, acrylonitrile, propylene oxide, acrylic acid, butanol, octanol, and nylon 66. With the global economic recovery, the demand for propylene is also increasing year by year; therefore, the production of propylene from propane has broad application prospects.

[0003] Propane production mainly involves two methods: direct dehydrogenation and oxidative dehydrogenation. Direct propane dehydrogenation has been industrialized, but it is an endothermic reaction requiring a high energy input. Furthermore, the reaction is limited by thermodynamic equilibrium, necessitating higher temperatures to achieve higher conversion rates. However, high temperatures can lead to cracking and catalyst coking, hindering the reaction's continuation. Oxidative dehydrogenation, on the other hand, is exothermic and not limited by thermodynamic equilibrium. Theoretically, it can achieve high conversion rates at lower temperatures and also reduces the likelihood of catalyst deactivation due to coking. Therefore, oxidative dehydrogenation has attracted considerable research interest. However, due to the introduction of O2, propylene is more easily oxidized into unusable CO compared to propane. x Therefore, improving the selectivity and yield of propylene has become a major challenge.

[0004] Currently, patents related to the oxidation of propane to propylene mainly focus on the composition of catalysts and their preparation processes. The catalysts are primarily powdered particles containing elements such as V, Mo, Ce, and Zn. CN1396146 discloses a catalyst using SBA-15 molecular sieve as a support and V as the active component, achieving a propane conversion of 50% and a propylene selectivity of 72% at 600℃, with a yield of 36%. CN1073893A discloses a Ce-containing catalyst, achieving a propane conversion of 53.4% ​​and a propylene selectivity of 67.5% at 500℃, with a yield of 35%. Furthermore, patents CN106944088A, CN103030496A, CN115055182A, CN114819770A, and CN103769136A provide similar catalysts. Patents CN114835545A and CN104447164A provide process technology for the production of propylene from propane, which adopts a fixed-bed oxidation process and achieves a propane conversion rate of 45.2% and a propylene selectivity of 75.1% at 500℃.

[0005] As can be seen from existing patents, the existing problems with propane oxidation to propylene technology are low propane conversion rate and selectivity. At the same time, due to the high reaction temperature (400-600℃), the conversion of propane to COx leads to high material loss and explosion risk. Therefore, it is urgent to develop new technologies to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to address the problems of low propane conversion, poor propylene selectivity, high propane loss at high temperatures, and susceptibility to explosion in existing propane oxidative dehydrogenation processes. This invention provides a method, system, and application for the oxidative production of propylene from propane using a microchannel reactor at a lower temperature. The reaction is carried out within a microchannel reactor made of a catalyst, avoiding the problem of catalyst loading. Because the gas is separated into small bubbles by segments of acid solution within the microchannel reactor, the problem of easy explosion during propane oxidation is solved. By utilizing the efficient mass and heat transfer characteristics of the microreactor, high conversion of propane and high selectivity of propylene are achieved at or near room temperature.

[0007] The first aspect of the present invention is to provide a method for oxidizing propane to propylene using a microchannel reactor, comprising mixing and contacting a mixture of propane and oxygen in a microchannel reactor in the presence of an acid solution to obtain propylene; wherein the microchannel reactor is made of a catalyst material for catalyzing the oxidation of propane to propylene.

[0008] The copper content in the catalyst material is more than 97 wt%.

[0009] According to the present invention, the content of copper in the catalyst material is more than 97 wt%. According to some preferred embodiments of the present invention, the catalyst material contains copper, optional iron and optional oxygen. Preferably, the content of iron in the catalyst material is 0-1 wt%, and / or the content of oxygen is 0-1.5 wt%.

[0010] More preferably, the catalyst material contains 0.5-1 wt% iron and / or 0.5-1.5 wt% oxygen. In the presence of an acidic solution, a significant portion of the iron and Cu oxide will be lost during the reaction, forming an uneven structure on the inner wall of the microchannel reactor. This increases the specific surface area of ​​the reaction, improving the conversion rate and selectivity of the product.

[0011] According to some preferred embodiments of the present invention, the equivalent diameter of the microchannel reactor is 0.4-1 mm, preferably 0.4-0.8 mm. The equivalent diameter of the microchannel reactor refers to the equivalent diameter of the reaction channel cross-section. Under this preferred equivalent diameter condition, the formed gas column / bubble has a smaller equivalent diameter, resulting in a shorter mass transfer distance from the gas to the catalyst surface during flow within the microchannel reactor. Simultaneously, the gas convection within the gas phase is stronger due to the drag resistance from the surface of the microchannel reactor, leading to higher propane conversion and better propylene selectivity.

[0012] According to the present invention, the length of the microchannel reactor can be selected from a wide range. According to some preferred embodiments of the present invention, the length of the microchannel reactor is 2-3m.

[0013] According to the present invention, the channel cross-sectional shape of the microchannel reactor has a wide range of selection. According to some preferred embodiments of the present invention, the channel cross-section of the microchannel reactor is a combination of one or more shapes selected from T-shape, Y-shape, cross-shape, and coaxial ring tube, preferably T-shape and / or Y-shape.

[0014] According to some preferred embodiments of the present invention, the molar ratio of oxygen to propane in the mixed gas is (2-3.5):1, preferably (2-3):1.

[0015] In this invention, for this reaction, the acid solution (i.e., liquid) acts as a gas separator, dividing the gas into segments, and does not participate in the oxidation reaction. Therefore, the gas-liquid flow rate can be adjusted within a wide range. According to some preferred embodiments of the invention, during feeding, the volumetric flow rate ratio of the mixed gas to the acid solution is (3-80):1, preferably (3-40):1. Under these preferred conditions, safety and convective mass transfer within the gas phase are further improved.

[0016] According to some preferred embodiments of the present invention, the acid solution is selected from one or more of sulfuric acid solution, hydrochloric acid solution, and acetic acid solution, preferably sulfuric acid solution.

[0017] According to some preferred embodiments of the present invention, the concentration of the acid solution is 0.6-1.2 mol / L, calculated as the concentration of hydrogen ions in the acid solution.

[0018] According to some preferred embodiments of the present invention, the conditions for the mixed contact reaction include: the temperature of the mixed contact reaction is 15-40°C, preferably 20-40°C, and / or the reaction pressure is 1-1.5 atm; and / or the residence time of the reaction is 0.1-3 min.

[0019] According to some preferred embodiments of the present invention, the method includes: mixing propane with oxygen, then carrying out a mixing contact reaction of the mixed gas in the presence of an acid solution in the microchannel reactor to obtain a reacted mixture, and separating the gas and liquid at the outlet of the reacted mixture to obtain propylene.

[0020] According to the present invention, the microchannel reactor is made of a catalyst material for catalytic oxidation of propane to propylene; the copper content in the catalyst material is 97 wt% or more. Preferably, the catalyst material contains copper, optional iron, and optional oxygen; more preferably, the iron content in the catalyst material is 0-1 wt%, and / or the oxygen content is 0-1.5 wt%; even more preferably, the iron content in the catalyst material is 0.5-1 wt%, and / or the oxygen content is 0.5-1.5 wt%. Therefore, the material of the microchannel reactor of the present invention can be selected from pure copper or copper material containing a small amount of oxygen and / or iron. The copper material for preparing the microchannel reactor can be obtained by directly purchasing it commercially or by customizing it through a service manufacturer, depending on the elemental composition of the material. For example, pure copper can be purchased directly from the market, while copper material containing a small amount of oxygen and / or iron can be purchased by customizing it by providing the material composition to the manufacturer.

[0021] The microchannel reactor of the specific material described in this invention can be prepared using existing technologies. In the prior art, it is common to machine metal raw materials, such as stainless steel, into microchannel reactors according to their size requirements, essentially machining them into metal tubes that meet the size requirements. For this invention, the specific copper material is machined into copper tubes that meet the requirements to serve as microchannel reactors. Preferably, a protective sleeve can be provided on the outside of the copper tube. The protective sleeve can be made of conventional materials used in microchannel reactor channels, such as pipes made of reaction-inert materials, or further, stainless steel tubes, nickel metal tubes, glass tubes, or ceramic tubes. Furthermore, this invention provides the specific material composition and specific size specifications of the microchannel reactor to a microchannel reactor manufacturer, who then manufactures the microchannel reactor according to existing conventional processes such as machining, meeting the specific material requirements and size specifications of this invention.

[0022] A second aspect of the present invention is to provide a microchannel reaction system, preferably used in the method for producing propylene from propane using a microchannel reactor as described in the first aspect;

[0023] This includes: propane source, oxygen source, acid solution source, and microchannel reactor.

[0024] The outlets of the propane source, oxygen source, and acid solution source are each connected to the inlet of the microchannel reactor via pipelines.

[0025] The microchannel reactor is made of a catalyst material used for the catalytic oxidation of propane to propylene, wherein the copper content in the catalyst material is above 97 wt%; preferably,

[0026] It also includes a temperature control device for controlling the temperature of the microchannel reactor.

[0027] The propane source in this invention includes, but is not limited to, Figure 1 The propane tanks used can also be pipelines supplying propane from upstream. Similarly, the oxygen source and acid solution source can also be supplied via pipelines, including but not limited to those using… Figure 1 The oxygen tank and sulfuric acid solution tank are among them.

[0028] According to some preferred embodiments of the invention, the catalyst material contains copper, optionally iron, and optionally oxygen.

[0029] According to some preferred embodiments of the present invention, the iron content in the catalyst material is 0-1 wt%, and / or the oxygen content is 0-1.5 wt%; more preferably,

[0030] The catalyst material contains 0.5-1 wt% iron and / or 0.5-1.5 wt% oxygen.

[0031] According to some preferred embodiments of the present invention, the equivalent diameter of the microchannel reactor is 0.4-1 mm, preferably 0.4-0.8 mm.

[0032] According to some preferred embodiments of the present invention, the length of the microchannel reactor is 2-3m.

[0033] According to some preferred embodiments of the present invention, the channel cross-section of the microchannel reactor is a combination of one or more shapes selected from T-shape, Y-shape, cross-shape, and coaxial ring tube, preferably T-shape and / or Y-shape.

[0034] According to some preferred embodiments of the present invention, a valve is also provided on the pipeline between the outlet of the propane source and the outlet of the oxygen source and the inlet of the microchannel reactor.

[0035] According to some preferred embodiments of the present invention, a horizontal flow pump is also included in the pipeline disposed between the outlet of the acid solution source and the inlet of the microchannel reactor.

[0036] According to some preferred embodiments of the present invention, a mixer is provided before the feed inlet of the microchannel reactor, and the feed inlet of the mixer is connected to the outlet of the propane source and the outlet of the oxygen source; preferably, the mixer is a three-way valve.

[0037] According to some preferred embodiments of the present invention, the outlet of the microchannel reactor is provided with a valve.

[0038] According to some preferred embodiments of the present invention, the microchannel reactor is disposed in a temperature control device, including but not limited to a water bath.

[0039] A third aspect of the present invention is to provide a method for the oxidation of propane to propylene using a microchannel reactor as described in the first aspect, or the application of a microchannel reaction system as described in the second aspect in the oxidation of propane to propylene.

[0040] The advantages of this invention are:

[0041] As mentioned above, the present invention provides a new method and system for the oxidation of propane to propylene using a microchannel reactor. Propane and oxygen are first mixed, and then the mixed gas and acid solution are mixed and reacted in a microchannel reactor made of catalyst. After a certain period of time, the gas and liquid are separated at the outlet due to the density difference between the gas and liquid.

[0042] The method provided by this invention solves the problems of low propane conversion rate, poor propylene selectivity, high propane loss at high temperatures, and easy explosion in the propane oxidation to propylene technology. The method of this invention can be carried out at room temperature or near room temperature (e.g., 15-40℃), which is safer than conventional catalytic reactions that require high temperature conditions.

[0043] This invention directly prepares the catalyst into a microchannel reactor, avoiding the problem of catalyst loading. Since the gas is separated into small bubbles by segments of acid solution in the microchannel reactor, the problem of easy explosion of propane oxidation is solved, which has great reference value for industrial application.

[0044] By utilizing the efficient mass and heat transfer characteristics of microreactors, propane can be prepared into propylene at room temperature or near room temperature, reducing the reaction time by more than 10 times compared to traditional reactors.

[0045] In addition to the advantages mentioned above, this invention also features high propane conversion rate, strong propylene selectivity, short reaction time, and higher efficiency, making it highly valuable for widespread application. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating a method and system according to one specific embodiment of the present invention.

[0047] Figure 1 In the middle: 1. Propane tank; 2. Oxygen tank; 3. Sulfuric acid solution tank; 4. Valve; 5. Valve; 6. Horizontal flow pump; 7. T-junction; 8. Microchannel reactor; 9. Outlet valve. Detailed Implementation

[0048] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0049] The following examples use Figure 1 The process proceeds from... Figure 1 It can be seen that propane from propane tank 1 via valve 4 and oxygen from oxygen tank 2 via valve 5 are mixed in three-way valve 7, and then mixed and reacted with dilute sulfuric acid from sulfuric acid solution tank 3 via horizontal flow pump 6 in microchannel reactor 8. The reaction products are separated from the liquid due to the gas-liquid density difference after passing through outlet valve 9. The microchannel reactor 8 is placed in a temperature control device. In the following embodiments, the temperature control device is a water bath.

[0050] In the following examples, the microchannel reactors used for catalyst preparation are simple T-shaped structures. The equivalent diameter (equivalent diameter of the channel cross-section) of the microchannel reactor is 0.4-1 mm, and the length is 2-3 m. The specific diameter and length are described in the examples. All microchannel reactors were customized by Tianjin Jinbin Petrochemical Equipment Co., Ltd.

[0051] In the following embodiments, the conversion rate in the table refers to propylene conversion rate; selectivity refers to propylene selectivity.

[0052] The method for calculating propylene conversion rate is as follows:

[0053] The method for calculating propylene selectivity is as follows:

[0054] Example 1

[0055] To verify the effectiveness of this invention, an oxygen to propane molar ratio of 2 was used as the research object. The sulfuric acid solution concentration was 0.3 mol / L (i.e., the concentration as hydrogen ions was 0.6 mol / L), the reaction temperature was 40℃, the reaction pressure was 1 atm, and the catalyst consisted of copper, iron, and oxygen elements, with iron content of 0.5 wt%, oxygen content of 0.5 wt%, and copper content of 99 wt%. The microchannel reactor made of the catalyst had an equivalent diameter of 0.4 mm and a length of 3 m. The flow rate of the mixed gas was controlled at 1.5 mL / min, the flow rate of the sulfuric acid solution was 0.5 mL / min, and the residence time was 0.19 min.

[0056] The results are as follows:

[0057] Propane oxidative dehydrogenation performance ％ Conversion rate 54 Selective 91

[0058] Comparative Example 1

[0059] To verify the effectiveness of this invention, an oxygen to propane molar ratio of 2 was used as the research object. The sulfuric acid solution concentration was 0.3 mol / L, the reaction temperature was 40℃, the reaction pressure was 1 atm, and the catalyst consisted of copper, iron, and oxygen elements, with iron content of 0.5%, oxygen content of 0.5%, and copper content of 99%. The catalyst dosage was 50.1 g, and the catalyst was in granular form. The reaction was carried out in a fixed bed with a diameter of 1 cm and a height of 0.6 m. The mixed gas flow rate was controlled at 160 mL / min, the sulfuric acid solution flow rate at 60 mL / min, and the residence time at 0.2 min. The results are as follows:

[0060] Propane oxidative dehydrogenation performance ％ Conversion rate 14 Selective 35

[0061] Example 2

[0062] The sulfuric acid concentration was 0.6 mol / L, and other parameters were the same as in Example 1. The results are as follows.

[0063]

[0064]

[0065] Example 3

[0066] The reaction temperature was 15°C, and other conditions were the same as in Example 1. The results are as follows.

[0067] Propane oxidative dehydrogenation performance ％ Conversion rate 45 Selective 85

[0068] Example 4

[0069] The reaction pressure was 1.5 atm, and other conditions were the same as in Example 1. The results are as follows.

[0070] Propane oxidative dehydrogenation performance ％ Conversion rate 56 Selective 89

[0071] Example 5

[0072] The iron content was 1 wt%, the oxygen content was 0 wt%, and the copper content was 99 wt%. Other parameters were the same as in Example 1. The results are as follows.

[0073] Propane oxidative dehydrogenation performance ％ Conversion rate 58 Selective 93

[0074] Example 6

[0075] The oxygen content was 1.5 wt%, the iron content was 0 wt%, and the copper content was 98.5 wt%. Other parameters were the same as in Example 1. The results are as follows.

[0076]

[0077]

[0078] Example 7

[0079] The microchannel reactor had an equivalent diameter of 1 mm, the mixed gas flow rate was controlled at 9.5 mL / min, the sulfuric acid solution flow rate was controlled at 3.2 mL / min, and the residence time was 0.19 min; other parameters were the same as in Example 1, and the results are as follows.

[0080] Propane oxidative dehydrogenation performance ％ Conversion rate 45 Selective 84

[0081] Example 8

[0082] The microchannel reactor was 2m long, and other parameters were the same as in Example 1. The residence time was 0.13min, and the results are as follows.

[0083] Propane oxidative dehydrogenation performance ％ Conversion rate 53 Selective 91

[0084] Example 9

[0085] The molar ratio of oxygen to propane was 3.5, and other parameters were the same as in Example 1. The results are as follows.

[0086] Propane oxidative dehydrogenation performance ％ Conversion rate 63 Selective 82

[0087] Example 10

[0088] The reaction temperature was 35°C, and other conditions were the same as in Example 1. The results are as follows.

[0089]

[0090]

[0091] Example 11

[0092] The microchannel reactor has an equivalent diameter of 1 mm, the mixed gas flow rate is controlled at 0.6 mL / min, the sulfuric acid solution flow rate is controlled at 0.2 mL / min, the residence time is 3 min, and other parameters are the same as in Example 1.

[0093] Propane oxidative dehydrogenation performance ％ Conversion rate 42 Selective 81

[0094] Example 12

[0095] The molar ratio of oxygen to propane was 3, and other parameters were the same as in Example 1. The results are as follows.

[0096] Propane oxidative dehydrogenation performance ％ Conversion rate 61 Selective 92

[0097] Example 13

[0098] The flow rate of the mixed gas was controlled at 2 mL / min, and the flow rate of the sulfuric acid solution was controlled at 0.05 mL / min. Other parameters were the same as in Example 1. The results are as follows.

[0099] Propane oxidative dehydrogenation performance ％ Conversion rate 58 Selective 87

[0100] As mentioned earlier, other types of catalysts cannot currently be effectively loaded into microchannels, and the gas-phase reaction requires temperatures above 500°C, which presents numerous drawbacks. As shown in Comparative Example 1, at a reaction temperature of 40°C, both the conversion rate and selectivity are particularly low, making it unsuitable for industrial production.

[0101] As can be seen from the above embodiments, the present invention uses a microchannel reactor made of copper-based material (copper content in the catalyst material is more than 97 wt%) to produce propylene from propane oxidative dehydrogenation, implements propylene preparation under low temperature conditions, and also has high conversion rate and propylene selectivity.

[0102] Furthermore, since the catalyst of this invention is an alloy or metallic catalyst, it can be easily fabricated into a microchannel reactor. As the reaction proceeds, a small portion of the catalyst (such as copper or iron) will be oxidized, and the oxides will be carried away by the sulfuric acid solution. Therefore, no special regeneration process is required, and the catalytic reaction can proceed continuously. At the same time, the acid solution used in the reaction system will remove a small amount of oxides from the catalyst surface, resulting in an uneven microstructure that increases the specific surface area. Under the condition of equivalent diameter, this is more conducive to the reaction.

[0103] After a long period of operation, such as six months or a year, the microchannel reactor can be replaced with a new microchannel reactor made of a new catalyst, depending on its specific condition (e.g., whether the equivalent diameter is too large). Since the microchannel reactor of this invention is made primarily of copper, it has the advantage of lower cost compared to conventional catalysts, and the materials from the old microchannel reactor can also be recycled.

[0104] As can be seen from the comparison of Examples 3, 7 and 11 with Example 1, under the preferred reaction temperature and preferred equivalent diameter conditions of the present invention, the method of the present invention has higher propylene conversion and selectivity.

[0105] As can be seen from the examples, the oxidative dehydrogenation of propane to propylene in a microchannel reactor can achieve propylene selectivity and comparable propane conversion rates far exceeding those reported in existing patents. Furthermore, by fabricating the catalyst into a microchannel reactor, the problem of catalyst loading is avoided. Moreover, because the gas is separated into small bubbles by segments of sulfuric acid solution within the microchannel reactor, the problem of easy explosion during propane oxidation is solved. This has significant implications for industrial applications. Based on this invention, changes to the catalyst composition and the use of other microchannel reactors will be readily apparent to those skilled in the art. Therefore, any improvements and modifications made without departing from the spirit of this invention are within the scope of protection claimed by this invention.

[0106] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0107] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0108] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0109] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0110] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0111] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A method for producing propylene from propane using a microchannel reactor, comprising reacting a mixture of propane and oxygen in the presence of an acid solution in a microchannel reactor to obtain propylene; wherein, The microchannel reactor is made of a catalyst material used for the catalytic oxidation of propane to propylene. The copper content in the catalyst material is more than 97 wt%.

2. The method according to claim 1, characterized in that: The catalyst material contains copper, optionally iron, and optionally oxygen; preferably, The catalyst material contains 0-1 wt% iron and / or 0-1.5 wt% oxygen; more preferably, The catalyst material contains 0.5-1 wt% iron and / or 0.5-1.5 wt% oxygen.

3. The method according to claim 1, characterized in that: The equivalent diameter of the microchannel reactor is 0.4-1 mm, preferably 0.4-0.8 mm; and / or, The microchannel reactor is 2-3 m in length; and / or, The cross-section of the microchannel reactor is a combination of one or more shapes selected from T-shape, Y-shape, cross-shape, and coaxial ring tube, preferably T-shape and / or Y-shape.

4. The method according to claim 1, characterized in that: The molar ratio of oxygen to propane in the gas mixture is (2-3.5):1, preferably (2-3):1; and / or, During feeding, the volumetric flow rate ratio of the mixed gas to the acid solution is (3-80):1, preferably (3-40):1; and / or, The acid solution is selected from one or more of sulfuric acid solution, hydrochloric acid solution, and acetic acid solution, preferably a sulfuric acid solution; and / or, The concentration of the acid solution is 0.6-1.2 mol / L, calculated based on the concentration of hydrogen ions in the acid solution.

5. The method according to claim 1, characterized in that: The conditions for the mixed contact reaction include: a temperature of 15-40°C, preferably 20-40°C, and / or a reaction pressure of 1-1.5 atm; and / or a residence time of 0.1-3 min.

6. The method according to any one of claims 1-5, characterized in that, The method includes: Propane is mixed with oxygen, and then the mixed gas is subjected to a mixing contact reaction in the microchannel reactor in the presence of an acid solution to obtain a reaction mixture. The reaction mixture is then subjected to gas-liquid separation at the outlet to obtain propylene.

7. A microchannel reaction system, preferably used in the method for producing propylene from propane using a microchannel reactor as described in any one of claims 1-6; include: Propane source, oxygen source, acid solution source, and microchannel reactor. The outlets of the propane source, oxygen source, and acid solution source are each connected to the inlet of the microchannel reactor via pipelines. The microchannel reactor is made of a catalyst material used for the catalytic oxidation of propane to propylene, wherein the copper content in the catalyst material is above 97 wt%; preferably, It also includes a temperature control device for controlling the temperature of the microchannel reactor.

8. The microchannel reaction system according to claim 7, characterized in that: The catalyst material contains copper, optionally iron, and optionally oxygen; preferably, The catalyst material contains 0-1 wt% iron and / or 0-1.5 wt% oxygen; more preferably, The catalyst material contains 0.5-1 wt% iron and / or 0.5-1.5 wt% oxygen; and / or The equivalent diameter of the microchannel reactor is 0.4-1 mm, preferably 0.4-0.8 mm; and / or, The length of the microchannel reactor is 2-3m; And / or, the channel cross-section of the microchannel reactor is a combination of one or more shapes selected from T-shape, Y-shape, cross-shape, and coaxial ring tube, preferably T-shape and / or Y-shape.

9. The microchannel reaction system according to claim 7 or 8, characterized in that: It also includes valves installed on the pipeline between the outlets of the propane source and oxygen source and the inlet of the microchannel reactor; and / or, It also includes a horizontal flow pump installed on the pipeline between the outlet of the acid solution source and the inlet of the microchannel reactor; and / or, A mixer is provided before the feed inlet of the microchannel reactor, and the feed inlet of the mixer is connected to the outlet of the propane source and the outlet of the oxygen source; preferably, the mixer is a three-way valve. And / or, the outlet of the microchannel reactor is equipped with a valve; And / or, the microchannel reactor is disposed in a temperature control device.

10. A method for oxidizing propane to propylene using a microchannel reactor according to any one of claims 1-6, or the application of a microchannel reaction system according to any one of claims 7-9 in the oxidization of propane to propylene.

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