A system and method for micro-photocatalytic dehydrogenation of low-carbon alkanes to olefins in the absence of oxygen

Abstract

The present application relates to a kind of micro light catalytic low carbon alkane oxygen-free dehydrogenation system and method of olefin, belong to photocatalytic energy conversion technical field, including the reaction atmosphere control system, photocatalytic reaction-catalyst regeneration circulation system, gas switching system and product detection system being sequentially communicated;The photocatalytic reaction-catalyst regeneration circulation system includes light source and quartz reactor, the light source and quartz reactor are provided with multiple groups, the quartz reactor is used to load catalyst and quartz sand, the reaction atmosphere control system is used to transport atmosphere to quartz reactor, the gas switching system is used to transmit the product of quartz reactor to product detection system.The system and method in the present application realize the alternative synergic circulation of photocatalytic alkane oxygen-free dehydrogenation reaction and catalyst in-situ regeneration, and realize continuous flow alkane oxygen-free dehydrogenation high selectivity olefin reaction and catalyst fast in-situ regeneration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photocatalytic energy conversion, in particular to a system and method for micro-photocatalytic dehydrogenation of low-carbon alkanes to olefins. BACKGROUND

[0002] The traditional route for alkanes to olefins is to crack crude oil or naphtha at high temperature, which is a harsh reaction condition, and has the characteristics of high cost and high energy consumption. Moreover, the high temperature leads to easy carbon deposition on the catalyst, thus reducing the catalytic efficiency. In recent years, photocatalytic technology has shown great vitality in the dehydrogenation of alkanes (including aerobic and anaerobic dehydrogenation). Light can reduce the energy barrier of the rate-limiting step of the catalytic reaction, or change the adsorption and desorption behavior of the reaction intermediates on the catalyst surface, thus changing the reaction selectivity. Therefore, compared with thermal catalysis, the catalyst can exhibit higher activity and ideal selectivity under solar-driven conditions, which fundamentally reduces energy consumption and production cost.

[0003] Generally, the process of catalytic dehydrogenation of low-carbon alkanes to the same carbon olefins requires the participation of O2 and generates water, completing the periodic reaction cycle. However, the aerobic dehydrogenation of alkanes with molecular oxygen is prone to over-oxidation of alkanes or product olefins, i.e. combustion of alkanes and olefins, generating CO, CH4 or CO2, which greatly reduces the yield and selectivity of the target product olefins; at the same time, the aerobic dehydrogenation reaction of alkanes releases a large amount of heat, which easily leads to the loss of control of the reactor; in addition, due to the flammability of the alkane-oxygen mixture, the conventional oxygen co-feeding catalytic system has serious safety hazards and needs an expensive air separation device to provide oxygen on site.

[0004] Compared with aerobic dehydrogenation, anaerobic dehydrogenation of alkanes can effectively inhibit over-oxidation and improve the selectivity of product olefins; however, anaerobic dehydrogenation of alkanes faces serious problems such as catalyst carbon deposition and sintering of the catalyst under high temperature conditions, which leads to easy deactivation of the catalyst. In addition, alkanes can also be partially oxidized on the surface of the catalyst by reacting with the lattice oxygen of the metal oxide catalyst, avoiding the direct participation of oxygen in the oxidation dehydrogenation reaction process of alkanes, i.e. reducing the production cost and improving the safety of the reaction system.

[0005] Using the lattice oxygen of the oxide to catalyze the anaerobic dehydrogenation of low-carbon alkanes under anaerobic and light conditions can significantly improve the selectivity of the same carbon olefins, but the lattice oxygen of the catalyst is gradually consumed due to uninterrupted participation in the oxidation dehydrogenation reaction, leading to deactivation of the catalyst.

[0006] In view of the above technical phenomena, the present application provides a micro-continuous photocatalytic dehydrogenation of low-carbon alkanes to olefins-catalyst in-situ regeneration system and method, to realize the efficient cycle of anaerobic dehydrogenation of low-carbon alkanes and in-situ regeneration of the catalyst. SUMMARY

[0007] The present application aims to provide a micro light catalytic system and method for dehydrogenation of low carbon alkane to olefin without oxygen, so as to realize the efficient cycle of low carbon alkane dehydrogenation reaction and catalyst in-situ regeneration.

[0008] The present application provides a micro light catalytic system for dehydrogenation of low carbon alkane to olefin without oxygen, which adopts the following technical scheme:

[0009] A micro light catalytic system for dehydrogenation of low carbon alkane to olefin without oxygen comprises a reaction atmosphere control system, a light catalytic reaction-catalyst regeneration circulation system, a gas switching system and a product detection system which are sequentially connected;

[0010] The light catalytic reaction-catalyst regeneration circulation system comprises a light source and a quartz reactor, and the light source and the quartz reactor are provided in multiple groups. The quartz reactor is used for loading catalyst and quartz sand. The reaction atmosphere control system is used for delivering atmosphere into the quartz reactor. The gas switching system is used for transmitting the product of the quartz reactor to the product detection system.

[0011] Preferably, the reaction atmosphere control system comprises at least one group of first valve bodies, and the first valve body is any one of a three-way valve, a four-way valve or a six-way valve.

[0012] The gas switching system comprises at least one group of second valve bodies, and the second valve body is any one of a three-way valve, a four-way valve or a six-way valve.

[0013] Preferably, in the case that the light catalytic reaction-catalyst regeneration circulation system comprises two groups of quartz reactors, the reaction atmosphere control system comprises one group of first valve bodies, the gas switching system comprises one group of second valve bodies, and the light source is arranged above each group of quartz reactors.

[0014] One group of valve ports of the first valve body is used for delivering alkane dehydrogenation reaction gas into one group of quartz reactors. One group of valve ports of the second valve body is used for delivering the product of alkane dehydrogenation reaction to the product detection system.

[0015] The other group of valve ports of the first valve body is used for delivering air into the other group of quartz reactors for reducing the catalyst in the quartz reactor.

[0016] Preferably, in the case that the light catalytic reaction-catalyst regeneration circulation system comprises three groups of quartz reactors, the reaction atmosphere control system comprises two groups of first valve bodies, the gas switching system comprises two groups of second valve bodies, and the light source is provided in multiple groups, and the multiple groups of light sources are respectively arranged above each group of quartz reactors.

[0017] One group of valve ports of the first valve body is used to transport alkane dehydrogenation reaction gas into one group of quartz reactors, and one group of valve ports of the second valve body is used to transport alkane dehydrogenation reaction product into the product detection system;

[0018] One group of valve ports of the first valve body is used to transport argon into one group of quartz reactors for purging the quartz reactors.

[0019] One group of valve ports of the first valve body is used to transport air into one group of quartz reactors for reducing catalyst in the quartz reactors.

[0020] Preferably, the quartz reactor includes any one of a serpentine reactor, an elliptical reactor or a rectangular reactor.

[0021] Preferably, the light source is any one of a xenon lamp, a mercury lamp or an LED lamp.

[0022] Preferably, the product detection system includes any one of gas chromatography or liquid chromatography.

[0023] The present application also provides a micro-photocatalytic low-carbon alkane dehydrogenation method for producing olefins, which uses the above-mentioned micro-photocatalytic low-carbon alkane dehydrogenation system for producing olefins, and includes the following steps:

[0024] S1, sequentially and end-to-end connecting the reaction atmosphere control system, the photocatalytic reaction-catalyst regeneration circulation system, the gas switching system and the product detection system, wherein the quartz reactors in the photocatalytic reaction-catalyst regeneration circulation system are loaded with catalyst and quartz sand, and the light source is arranged above each group of quartz reactors;

[0025] S2, turning on the light source, opening one group of valve ports of the first valve body to introduce alkane dehydrogenation reaction gas into one group of quartz reactors to perform photocatalytic alkane dehydrogenation reaction, opening one group of valve ports of the second valve body to transport the product of the photocatalytic alkane dehydrogenation reaction to the product detection system for online analysis, simultaneously, opening another group of valve ports of the first valve body to introduce air into another group of quartz reactors, and opening another group of valve ports of the second valve body to exhaust the air in the other group of quartz reactors;

[0026] S3, 10 minutes later, simultaneously switch the first valve body and the second valve body in the reaction atmosphere control system and the gas switching system, a group of valve ports of the first valve body transports air into the quartz reactor for ending the photocatalytic alkane dehydrogenation reaction to perform in-situ regeneration of the catalyst, a group of valve ports of the second valve body is used for emptying the air in the quartz reactor for ending the photocatalytic alkane dehydrogenation reaction; another group of valve ports of the first valve body transports alkane dehydrogenation reaction gas into another group of quartz reactors to perform the photocatalytic alkane dehydrogenation reaction, and another group of valve ports of the second valve body transports the product of the photocatalytic alkane dehydrogenation reaction to the product detection system for online analysis.

[0027] S4, 10 minutes later, repeat steps S2 and S3, and cycle in this way.

[0028] Preferably, the quartz reactor in step S1 comprises at least two groups.

[0029] Preferably, the catalyst in step S1 is any one of CuO catalyst and MnCo2O4 catalyst.

[0030] The quartz sand in step S1 is 40-60 mesh.

[0031] The mass ratio of the catalyst to the quartz sand is 1: (1-2).

[0032] In summary, the present application has the following beneficial technical effects:

[0033] 1. The reaction atmosphere system in the system of the present application is used to control the atmosphere for photocatalytic low-carbon alkane dehydrogenation reaction and in-situ regeneration of the photocatalyst, that is, through the reaction atmosphere control system, alkane dehydrogenation reaction gas and catalyst regeneration gas are alternately introduced into different quartz reactors through the gas pipeline to complete photocatalytic reaction or in-situ regeneration of the catalyst, the gas switching system controls the continuous online analysis of the product of the alkane dehydrogenation reaction to determine the photocatalytic reaction efficiency, product selectivity and catalyst stability, realizes continuous flow photocatalytic alkane dehydrogenation to olefins, and the present application realizes the alternative and cooperative circulation of photocatalytic alkane dehydrogenation reaction and in-situ regeneration of the catalyst, does not need to replace the photocatalyst, does not use additional catalyst regeneration device, at the same time avoids repeated disassembly and installation of the quartz reactor, is convenient for actual use, improves the photocatalytic efficiency, and realizes continuous flow alkane dehydrogenation with high selectivity to olefins and rapid in-situ regeneration of the catalyst.

[0034] 2. The method in this application includes adjusting the atmosphere supplied to the photocatalytic reaction-catalyst in-situ regeneration cycle system through a reaction atmosphere control system. The atmosphere enters multiple quartz reactors through the reaction atmosphere control system to achieve alternating and coordinated circulation of photocatalytic alkane dehydrogenation to olefins and in-situ catalyst regeneration (or introducing gas pipelines in an inert gas purging device to the reactor). Through a product control system, alkane products are continuously fed into a product detection system for online analysis. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of a micro-photocatalytic system for the oxygen-free dehydrogenation of low-carbon alkanes to olefins, as described in Example 1 of this invention.

[0036] Figure 2 This is a schematic diagram of the structure of a micro-photocatalytic system for the oxygen-free dehydrogenation of low-carbon alkanes to olefins, as described in Example 2 of this invention.

[0037] Figure 3 This is a schematic diagram of the photocatalytic CuO ethane dehydrogenation performance in Example 1 of the present invention.

[0038] Figure 4 This is a schematic diagram of the photocatalytic dehydrogenation performance of MnCo2O4 propane in Example 2 of the present invention.

[0039] Explanation of reference numerals in the attached figures: 1. Reaction atmosphere control system; 11. First valve body; 2. Photocatalytic reaction-catalyst regeneration cycle system; 21. Quartz reactor; 22. Light source; 3. Gas switching system; 31. Second valve body; 4. Product detection system. Detailed Implementation

[0040] The following is in conjunction with the embodiments and appendices Figures 1-4 The present invention will be described in further detail below.

[0041] This invention provides a micro-photocatalytic system for the oxygen-free dehydrogenation of low-carbon alkanes to olefins, referring to... Figure 1 and Figure 2 The system includes a reaction atmosphere control system 1, a photocatalytic reaction-catalyst regeneration circulation system 2, a gas switching system 3, and a product detection system 4, which are connected in sequence. The reaction atmosphere control system 1 is used to control the atmosphere supplied to the photocatalytic reaction-catalyst regeneration circulation system 2. The photocatalytic reaction-catalyst regeneration circulation system 2 is used for photocatalytic reaction or in-situ regeneration of the catalyst. The gas switching system 3 is used to control the continuous delivery of the products of the alkane dehydrogenation reaction to the product detection system 4 for online analysis, so as to determine the photocatalytic reaction efficiency, product selectivity and catalyst stability, and realize continuous flow photocatalytic alkane dehydrogenation to olefins.

[0042] Reference Figure 1 and Figure 2, photocatalytic reaction-catalyst regeneration cycle system 2 includes light source 22 and quartz reactor 21, the quartz reactor 21 in the embodiment is one of existing conventional equipment, the quartz reactor 21 includes any one of serpentine reactor, oval reactor or rectangle reactor, for loading catalyst and quartz sand, enhance the contact area of catalyst and alkane dehydrogenation reaction gas, the catalyst can be any one of transition metal oxide semiconductor, the catalyst in the embodiment is preferably selected from any one of CuO catalyst, MnCo2O4 catalyst, the light source 22 plays an irradiation role to the quartz reactor 21, the light source 22 in the embodiment is any one of xenon lamp, mercury lamp or LED lamp; reaction atmosphere control system 1 is used to deliver atmosphere to the quartz reactor 21, so that the quartz reactor 21 carries out alkane dehydrogenation reaction, the light source 22 and the quartz reactor 21 are provided with multiple groups, the specific number of light source 22 and quartz reactor 21 in the embodiment is determined according to experiment; gas switching system 3 is used to transmit the product through the quartz reactor 21 to product detection system 4, the product detection system 4 includes any one of gas chromatography or liquid chromatography, the product detection system 4 in the embodiment is gas chromatography-mass spectrometer.

[0043] Referring to Figure 1 and Figure 2 , reaction atmosphere control system 1 at least includes a group of first valve body 11, the first valve body 11 is any one of three-way valve, four-way valve or six-way valve; gas switching system 3 at least includes a group of second valve body 31, the second valve body 31 is any one of three-way valve, four-way valve or six-way valve.

[0044] Referring to Figure 1 , the quartz reactor 21 in the embodiment is provided with two groups, and the light source 22 is arranged above each group of quartz reactor 21; reaction atmosphere control system 1 includes a group of first valve body 11, the first valve body 11 in the embodiment is selected as four-way valve, and gas switching system 3 includes a group of second valve body 31, the second valve body 31 in the embodiment is selected as four-way valve. One group of valve ports of the first valve body 11 is used to deliver alkane dehydrogenation reaction gas to one group of quartz reactor 21, and one group of valve ports of the second valve body 31 is used to deliver alkane dehydrogenation reaction product to product detection system 4; and the other group of valve ports of the first valve body 11 is used to deliver air to the other group of quartz reactor 21, so as to reduce the catalyst in the other group of quartz reactor 21, and the other group of valve ports of the second valve body 31 is used to empty the air in the quartz reactor 21.

[0045] Referring to Figure 2The quartz reactor 21 in the embodiment is provided with three groups, the light source 22 is provided with two groups, and the two groups of light sources 22 are located above each group of quartz reactors 21; the reaction atmosphere regulation system 1 includes two groups of first valve bodies 11, the first valve body 11 in the embodiment is selected as a six-way valve, the gas switching system 3 includes two groups of second valve bodies 31, and the second valve body 31 in the embodiment is selected as a four-way valve. Two groups of valve ports located in the two groups of first valve bodies 11 are connected in communication to convey alkane dehydrogenation reaction gas into one group of quartz reactors 21, two groups of valve ports located in the two groups of second valve bodies 31 are connected in communication to convey alkane dehydrogenation reaction products to the product detection system 4; the second group of valve ports located in the two groups of first valve bodies 11 are connected in communication to convey argon into the second group of quartz reactors 21, for purging the quartz reactor 21, and one group of valve ports of the second valve body 31 discharges the purge gas; the third group of valve ports located in the two groups of first valve bodies 11 are connected in communication to convey air into the third group of quartz reactors 21, for reducing the catalyst in the quartz reactor 21, and one group of valve ports of the second valve body 31 discharges the air in the third group of quartz reactors 21.

[0046] The application further provides a method for preparing olefins by micro-photocatalytic dehydrogenation of low-carbon alkanes without oxygen.

[0047] Test Example 1

[0048] A method for preparing olefins by micro-photocatalytic dehydrogenation of low-carbon alkanes using the system, referring to Figure 1 and Figure 3 , comprises the following steps:

[0049] S1, the reaction atmosphere regulation system 1, the photocatalytic reaction-catalyst regeneration circulation system 2, the gas switching system 3 and the product detection system 4 are sequentially connected in communication, the reaction atmosphere regulation system 1 in the test example includes one group of first valve bodies 11, the first valve body 11 is selected as a four-way valve, the photocatalytic reaction-catalyst regeneration circulation system 2 includes two groups of quartz reactors 21, the quartz reactor 21 is loaded with 0.15g of catalyst and 0.2g of quartz sand, the catalyst is selected as CuO catalyst, the quartz sand is 40-60 mesh, the light source 22 is arranged above each group of quartz reactors 21, the light source 22 adopts an LED lamp with a wavelength of 365nm, the position of the light source 22 is adjusted to converge directly above the quartz reactor 21, the gas switching system 3 includes one group of second valve bodies 31, and the second valve body 31 is selected as a four-way valve;

[0050] S2, turn on the light source 22, open two groups of valve ports of the first valve body 11, under the action of the gas flow, one group of valve ports of the first valve body 11 introduces the alkane dehydrogenation reaction gas into one of the quartz reactors 21, the alkane dehydrogenation reaction gas in this test example is ethane, the quartz reactor 21 carries out the photocatalytic alkane dehydrogenation reaction gas dehydrogenation reaction, opens one group of valve ports of the second valve body 31 connected with the output end of the quartz reactor 21 to transport the product of the photocatalytic alkane dehydrogenation reaction gas dehydrogenation reaction to the product detection system 4 for online analysis (i.e. A1→A2→R1→C1→C2→GCMS); at the same time, the other group of valve ports of the first valve body 11 is introducing air into the other quartz reactor 21 to reduce the catalyst in the other quartz reactor 21, opens the other group of valve ports of the second valve body 31 connected with the quartz reactor 21 to exhaust the air in the other quartz reactor 21 (i.e. A3→A4→R2→C3→C4);

[0051] S3, after 10 min, simultaneously switch the first valve body 11 and the second valve body 31 in the reaction atmosphere control system 1 and the gas switching system 3, one group of valve ports of the first valve body 11 transports air into the quartz reactor 21 ending the photocatalytic alkane dehydrogenation reaction gas dehydrogenation reaction for in-situ regeneration of the catalyst, one group of valve ports of the second valve body 31 is used to exhaust the air in the quartz reactor 21 ending the photocatalytic alkane dehydrogenation reaction gas dehydrogenation reaction; the other group of valve ports of the first valve body 11 transports the alkane dehydrogenation reaction gas into the other quartz reactor 21 for photocatalytic alkane dehydrogenation reaction gas dehydrogenation reaction, the other group of valve ports of the second valve body 31 transports the product of the photocatalytic alkane dehydrogenation reaction gas dehydrogenation reaction to the product detection system 4 for online analysis;

[0052] S4, after 10 min, repeat steps S2 and S3, and cycle in this way.

[0053] In this test example, the first valve body 11 is marked as A, the four groups of valve ports of the first valve body 11 are marked as A1, A2, A3, and A4; the two groups of reactors are marked as R1 and R2; the second valve body 31 is marked as B, the four groups of valve ports of the second valve body 31 are marked as B1, B2, B3, and B4; the product detection system 4 is marked as GCMS.

[0054] Test Example 2

[0055] A method for using a micro photocatalytic low-carbon alkane dehydrogenation system to produce olefins, referring to Figure 2 and Figure 4 , comprising the following steps:

[0056] S1, the reaction atmosphere control system 1, photocatalytic reaction-catalyst regeneration cycle system 2, gas switching system 3 and product detection system 4 are sequentially connected in order, the reaction atmosphere control system 1 in the test example includes two sets of first valve body 11, the two sets of first valve body 11 are selected as six-way valve, the photocatalytic reaction-catalyst regeneration cycle system 2 includes three sets of quartz reactor 21, the quartz reactor 21 is loaded with 0.2g catalyst and 0.2g quartz sand, the catalyst is selected as MnCo2O4 catalyst, the quartz sand is 40-60 mesh, the light source 22 is arranged above each set of quartz reactor 21, the light source 22 is selected as full-waveband light source, in the test example, it is 300 W xenon lamp, the position of the light source 22 is adjusted to make it converge directly above the quartz reactor 21, the gas switching system 3 includes two sets of second valve body 31, the second valve body 31 is selected as four-way valve;

[0057] S2, turn on the light source 22, open three sets of valve ports of two sets of first valve body 11, under the action of airflow, the first set of valve ports of two sets of first valve body 11 introduce propane into the first set of quartz reactor 21, the quartz reactor 21 carries out photocatalytic alkane dehydrogenation reaction, the valve port of two sets of second valve body 31 is opened to communicate with the output end of the first set of quartz reactor 21, so that the product of photocatalytic alkane dehydrogenation reaction is transported to the product detection system 4 for online analysis (i.e. A2→A1→B1→B2→R1→C2→C1→D1→D2→GCMS); at the same time, the second set of valve ports of two sets of first valve body 11 is introducing argon into the second set of quartz reactor 21, so as to purge the second set of quartz reactor 21, a set of valve ports of second valve body 31 is opened to communicate with the second set of quartz reactor 21, so as to exhaust the argon in the second set of quartz reactor 21 (i.e. A4→A3→B3→B4→R2→C4→C3); at the same time, the third set of valve ports of two sets of first valve body 11 is introducing air into the third set of quartz reactor 21, so as to reduce the catalyst in the third set of quartz reactor 21, the valve port of second valve body 31 is opened to communicate with the third set of quartz reactor 21, so as to exhaust the air in the third set of quartz reactor 21 (i.e. A6→A5→B5→B6→R3→D3→D4);

[0058] S3, after 10 min, switch one set of first valve body 11 and one set of second valve body 31, so as to introduce air into the first set of quartz reactor 21, to reduce the catalyst (i.e. A6→A1→B1→B2→R1→C2→C3); introduce propane into the second set of quartz reactor 21, to carry out photocatalytic propane dehydrogenation reaction, and then pump the product into the product detection system 4 through the gas switching system 3 for online analysis (i.e. A2→A3→B3→B4→R2→C4→C1→D1→D2→GC); introduce argon into the third set of quartz reactor 21 to purge (i.e. A4→A5→B5→B6→R3→C2→C4→D3);

[0059] S4, 10 min later, switch one group of first valve body 11 and second valve body 31 to the default state, and switch the other group of first valve body 11 and second valve body 31, to the first group of reactors to pass in argon for purging (i.e. A4→A3→B3→B2→R1→C2→C1→D1→D4); to the second group of reactors to pass in air for catalyst reduction (i.e. A6→A5→B5→B4→R2→C4→C3); to the third group of reactors to pass in propane for photocatalytic propane anaerobic dehydrogenation reaction (i.e. A1→A1→B1→B6→R3→D3→C2→GCMS);

[0060] S5, 10 min later, switch the other group of first valve body 11 and second valve body 31 to the default state, repeat the operation of step S2, step S3 and step S4, and perform multiple cycle reactions.

[0061] In the test example, the two groups of first valve body 11 are respectively marked as A and B, the four groups of valve ports of A are marked as A1, A2, A3, A4, A5, A6, and the four groups of valve ports of B are marked as A1, A2, A3, A4, A5, B6; the three groups of reactors are respectively marked as R1, R2, R3; the two groups of second valve body 31 are respectively marked as C and D, the four groups of valve ports of C are marked as C1, C2, C3, C4, and the four groups of valve ports of D are marked as D1, D2, D3, D4; the product detection system 4 is marked as GCMS.

[0062] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A system for the micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins, characterized in that, It includes a reaction atmosphere control system (1), a photocatalytic reaction-catalyst regeneration cycle system (2), a gas switching system (3), and a product detection system (4) that are connected in sequence. The photocatalytic reaction-catalyst regeneration cycle system (2) includes a light source (22) and a quartz reactor (21). Multiple sets of the light source (22) and the quartz reactor (21) are provided. The quartz reactor (21) is used to load the catalyst and quartz sand. The reaction atmosphere control system (1) is used to supply the atmosphere into the quartz reactor (21). The gas switching system (3) is used to transfer the product of the quartz reactor (21) to the product detection system (4). The reaction atmosphere control system (1) includes at least one set of first valves (11); the gas switching system (3) includes at least one set of second valves (31). In the state where the photocatalytic reaction-catalyst regeneration cycle system (2) includes two sets of quartz reactors (21), the reaction atmosphere control system (1) includes a set of first valves (11), the gas switching system (3) includes a set of second valves (31), and the light source (22) is set above each set of quartz reactors (21); A set of valve ports of the first valve body (11) is used to deliver alkane dehydrogenation reaction gas into a set of quartz reactors (21), and a set of valve ports of the second valve body (31) delivers alkane oxygen-free dehydrogenation reaction products to the product detection system (4). The other set of valve ports of the first valve body (11) is used to supply air into another set of quartz reactors (21) for reducing the catalyst in the quartz reactors (21); In the state where the photocatalytic reaction-catalyst regeneration cycle system (2) includes three sets of quartz reactors (21), the reaction atmosphere control system (1) includes two sets of first valve bodies (11), the gas switching system (3) includes two sets of second valve bodies (31), and multiple sets of light sources (22) are provided, with each set of light sources (22) being located above each set of quartz reactors (21). One set of valve ports of the two sets of first valve bodies (11) is used to deliver alkane dehydrogenation reaction gas into a set of quartz reactors (21), and one set of valve ports of the two sets of second valve bodies (31) delivers alkane oxygen-free dehydrogenation reaction products to the product detection system (4). One set of valve ports of the two sets of first valve bodies (11) is used to deliver argon gas into a set of quartz reactors (21) for purging the quartz reactors (21). One set of valve ports of the two sets of first valve bodies (11) is used to supply air into a set of quartz reactors (21) for reducing the catalyst in the quartz reactors (21).

2. The system for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins according to claim 1, characterized in that, The first valve body (11) is any one of a three-way valve, a four-way valve, or a six-way valve; The second valve body (31) is any one of a three-way valve, a four-way valve, or a six-way valve.

3. The system for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins according to claim 1, characterized in that, The quartz reactor (21) includes any one of a serpentine reactor, an elliptical reactor, or a rectangular reactor.

4. The system for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins according to claim 1, characterized in that, The light source (22) is any one of a xenon lamp, a mercury lamp, or an LED lamp.

5. The system for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins according to claim 1, characterized in that, The product detection system (4) includes either gas chromatography or liquid chromatography.

6. A method for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins, characterized in that, The system for micro-photocatalytic dehydrogenation of low-carbon alkanes to olefins as described in any one of claims 1-5 includes the following steps: S1. Connect the reaction atmosphere control system (1), photocatalytic reaction-catalyst regeneration cycle system (2), gas switching system (3) and product detection system (4) in sequence. The quartz reactor (21) in the photocatalytic reaction-catalyst regeneration cycle system (2) is loaded with catalyst and quartz sand. The light source (22) is set above each group of quartz reactors (21). S2. Turn on the light source (22), open a set of valves of the first valve body (11), and introduce alkane dehydrogenation reaction gas into a set of quartz reactors (21) to carry out photocatalytic alkane dehydrogenation reaction. Open a set of valves of the second valve body (31) to transport the product of the photocatalytic alkane dehydrogenation reaction to the product detection system (4) for online analysis. At the same time, open another set of valves of the first valve body (11) to introduce air into another set of quartz reactors (21) and open another set of valves of the second valve body (31) to exhaust the air in the other set of quartz reactors (21). S3, 10 min later, the first valve body (11) and the second valve body (31) in the reaction atmosphere control system (1) and the gas switching system (3) are switched simultaneously. One set of valves of the first valve body (11) supplies air to the quartz reactor (21) after the photocatalytic alkane dehydrogenation reaction has ended to regenerate the catalyst in situ. One set of valves of the second valve body (31) is used to vent the air from the quartz reactor (21) after the photocatalytic alkane dehydrogenation reaction has ended. Another set of valves of the first valve body (11) supplies alkane dehydrogenation reaction gas to another set of quartz reactors (21) to carry out the photocatalytic alkane dehydrogenation reaction. Another set of valves of the second valve body (31) supplies the product of the photocatalytic alkane dehydrogenation reaction to the product detection system (4) for online analysis. S4. After 10 minutes, repeat steps S2 and S3, and continue this cycle.

7. The method for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins according to claim 6, characterized in that, The quartz reactor (21) in step S1 includes at least two sets.

8. The method for micro-photocatalytic oxygen-free dehydrogenation of low-carbon alkanes to olefins according to claim 6, characterized in that, The catalyst in step S1 is either a CuO catalyst or a MnCo2O4 catalyst. The quartz sand in step S1 is 40-60 mesh; The mass ratio of the catalyst to the quartz sand is 1:(1-2).

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