Cascade photoelectrocatalysis reaction device for preparing alcohols by alkane conversion

Abstract

The utility model relates to a cascade photoelectrocatalytic reaction device for preparing alcohols by alkane conversion, which comprises an electrocatalytic reaction component, a photocatalytic reaction component, an alkane gas cylinder (6), a three-way valve a (7), a continuous flow reactor (11) and a product collecting tank (12). A three-way valve a (7) is arranged on the connecting pipeline, the three-way valve a (7) is further connected with an alkane gas cylinder (6), and the photocatalytic reaction assembly is sequentially connected with a continuous flow reactor (11) and a product collecting tank (12) through pipelines. Compared with the prior art, the device has excellent alcohol selectivity and production efficiency, and is a more efficient and stable reaction system compared with the currently reported electro-catalysis or photocatalysis technology.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of alkane conversion preparation alcohol, especially, it is involved in a kind of cascade photoelectrocatalysis reaction device for alkane conversion preparation alcohol. BACKGROUND

[0002] Low-carbon alcohols such as methanol, ethanol and propanol are important bulk chemicals and are widely used in various fields. Currently, the production of low-carbon alcohols usually relies on a multi-step thermal catalytic process under high temperature and high pressure, which has the problems of low reaction efficiency and high energy consumption. Based on the problems of high carbon emission and high energy consumption in current industrial alcohol production, using renewable electricity and water, small molecule alkanes can be directly synthesized into alcohols under normal temperature and pressure, which is a revolutionary technology for low-energy and low-carbon chemical industry.

[0003] As an efficient catalytic method using clean energy, electrocatalysis and photocatalysis can be used for cascade conversion of alkanes to prepare alcohols. Patent CN202210881505.8 discloses a horizontal opposed double light window gas diffusion electrolytic cell for photoelectrocatalysis and application, which includes a gas diffusion photo-cathode cell and a gas diffusion photo-anode cell in a horizontal opposed same-side light receiving configuration. The gas diffusion photo-cathode cell includes a quartz window assembly connected by bolts, a photo-cathode liquid flow chamber, a gas diffusion photo-cathode and a cathode flow channel plate. The photo-cathode liquid flow chamber is installed with a reference electrode at the outer end. The gas diffusion photo-anode cell includes a quartz window assembly connected by bolts, a photo-anode liquid flow chamber, a gas diffusion photo-anode and an anode flow channel plate. This technology optimizes the photo-cathode and photo-anode to a horizontal opposed same-side light receiving configuration, and includes a gas diffusion electrode assembly, which improves the utilization of photoelectric catalytic conversion light energy and the mass transfer efficiency of small molecules. However, in the reaction of alkane conversion to prepare alcohols, the application of this device is still limited. First, the solubility of alkanes in aqueous solution system is very low, which directly leads to insufficient concentration of effective reactants in the reactor, which not only limits the mass transfer efficiency of catalytic reaction, but also makes it difficult to fully realize the advantages of photoelectric cathode and anode synergistic effect. Second, although this technology uses a horizontal opposed same-side light receiving configuration, which can reduce the operating cost by using a single light source, the reaction of alkane conversion to alcohol often involves a complex multi-step cascade process. The existing design lacks segmented fine control of the reaction path, which easily leads to accumulation of intermediate products or by-products, thereby reducing the selectivity and yield of target products.

[0004] Therefore, the existing technology still lacks a device that can effectively combine electrocatalysis and photocatalysis to achieve efficient conversion of alkanes to alcohols. UTILITY MODEL CONTENT

[0005] The utility model disc purposes to overcome the defects of the prior art and provide a cascade photoelectrocatalytic reaction device for preparing alcohol from alkane, realize the synergistic effect of electrocatalysis and photocatalysis, and improve product conversion efficiency and selectivity.

[0006] The utility model disc purposes to overcome the defects of the prior art and provide a cascade photoelectrocatalytic reaction device for preparing alcohol from alkane, realize the synergistic effect of electrocatalysis and photocatalysis, and improve product conversion efficiency and selectivity.

[0007] Further, the electrocatalytic reaction assembly comprises a membrane electrode electrolytic cell and a cathode liquid tank and an anode liquid tank connected thereto.

[0008] Further, the membrane electrode electrolytic cell comprises a proton exchange membrane and a cathode and an anode arranged on both sides of the proton exchange membrane; the cathode liquid tank is connected to the cathode, and the anode liquid tank is connected to the anode.

[0009] Further, the anode electrolyte outlet of the membrane electrode electrolytic cell is connected to the three-way valve a.

[0010] Further, the electrolyte stored in the cathode liquid tank and the anode liquid tank is a NaCl, KCl, NaBr, KBr, Nal or KI solution.

[0011] Further, the photocatalytic reaction assembly comprises a light source and a photocatalytic reactor.

[0012] Further, the photocatalytic reactor outlet is connected to the continuous flow reactor through a pipeline, a three-way valve b is arranged on the connecting pipeline, and the three-way valve b is further connected to the electrocatalytic reaction assembly through a pipeline.

[0013] Further, the photocatalytic reactor is a transparent microchannel with an inner diameter of 1.5-10 mm.

[0014] Further, the light source used is an LED lamp, the output power of the LED lamp is 3-20 W, and the wavelength is 320-365 nm.

[0015] Further, the continuous flow reactor is a reactor with an inner diameter of 1.5-10 mm and made of PFA, glass or quartz.

[0016] The utility model relates to the cascade photoelectric catalytic device for realizing the efficient conversion of alkane to alcohol compound.

[0017] The gaseous product after separation is mixed with the cathode electrolyte from the electrocatalytic reaction tank in another three-way valve and is delivered to the continuous flow reactor through the pipeline.

[0018] Compared with the prior art, the utility model has the following excellent effects:

[0019] (1) The utility model connects the electrocatalytic reaction tank and the photocatalytic reaction tank through cascade design, realizes the synergistic effect of electrocatalysis and photocatalysis, and improves the product conversion efficiency and selectivity. - The surface wave oscillation formed by the gas-liquid interface in the photo reactor can accelerate the interface update, thereby improving the alkane mass transfer coefficient, and finally realizing the matching of photoelectric reaction rate.

[0020] Compared with the prior art, the utility model realizes double breakthrough in current density and selectivity, and the maximum partial current density exceeds 240mA / cm 2 (while the currently reported technology is generally lower than 20mA / cm 2 ), and still maintains excellent alcohol selectivity and production efficiency for more than 100 hours of continuous operation. Compared with the currently reported electrocatalytic or photocatalytic technology, it is a more efficient and stable reaction system, suitable for high-selectivity alcohol preparation under industrial-grade current density.

[0021] (2) The utility model adopts continuous flow operation mode, optimizes mass transfer efficiency, overcomes the problem of low mass transfer efficiency of the existing closed system, and ensures the uniformity and stability of the reaction.

[0022] (3) The utility model realizes accurate control of the mixing ratio of gas-liquid / gas, and improves the material utilization efficiency in the reaction process.

[0023] (4) The LED light source is introduced in the photocatalytic reaction stage to provide efficient and stable light conditions and enhance the photocatalytic conversion effect of alkanes.

[0024] (5) The modular device design enhances the stability of the system and makes the operation more simple and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the structure front view schematic drawing of the utility model;

[0026] Figure 2 It is the isometric view of the utility model;

[0027] Figure 3 It is the enlarged view of the photocatalytic reactor structure of the utility model.

[0028] In the drawing, 1 is a cathode liquid tank, 2 is an anode liquid tank, 3 is a membrane electrode electrolytic cell, 4 is an electrolytic cell cathode, 5 is an electrolytic cell anode, 6 is an alkane gas cylinder, 7 is a three-way valve a, 8 is an LED lamp, 9 is a photocatalytic reactor, 10 is a three-way valve b, 11 is a continuous flow reactor, and 12 is a product collection tank. DETAILED DESCRIPTION

[0029] The utility model will be described in detail below in combination with specific embodiments. The embodiments are implemented on the premise of the technical scheme of the utility model, and detailed implementation modes and specific operation processes are given, but the protection scope of the utility model is not limited to the following examples.

[0030] In the following examples, if there is no special description of components or processing technology, it means that they are all conventional commercially available components or conventional processing technology in the art.

[0031] Example 1

[0032] As shown in Figures 1-2 A cascade photoelectrocatalytic reaction device for converting alkanes to alcohols comprises:

[0033] Catholyte tank 1: used for storing catholyte for electrolysis process. In this embodiment, NaCl solution is chosen as electrolyte.

[0034] Anolyte tank 2: used for storing anolyte to ensure the continuous progress of anodic reaction. In this embodiment, NaCl solution is chosen as electrolyte.

[0035] Membrane electrode electrolytic cell 3: the key device for electrocatalytic reaction, including cathode 4, anode 5 and the separator membrane (usually proton exchange membrane, i.e. cathode 4 and anode 5 are sandwiched on both sides of the proton exchange membrane to form the membrane electrode electrolytic cell), to ensure efficient reaction.

[0036] Cathode 4: set inside the electrolytic cell, used for cathodic electrochemical reaction, and catholyte tank 1 is connected to cathode 4.

[0037] Anode 5: set inside the electrolytic cell, used for anodic electrochemical reaction, and anolyte tank 2 is connected to anode 5.

[0038] Alkane gas cylinder 6: provides alkane gas raw materials required for the reaction, ensuring the stability of raw material supply.

[0039] Three-way valve a7: used for mixing the solution after anodic electrolysis with alkane gas to achieve efficient delivery of reactants. Three-way valve a7 is connected to the anodic electrolyte outlet of membrane electrode electrolytic cell 3, alkane gas cylinder 6 and photocatalytic reactor 9 respectively.

[0040] LED lamp 8: as a light source device, providing the required light conditions for photocatalytic reaction.

[0041] Photocatalytic reactor 9: the key device for photocatalytic reaction, ensuring precise control of reaction conditions. Generally, a transparent microchannel with an inner diameter of 1.5-10 mm can be chosen, and its material includes PFA, glass or quartz, etc. In this embodiment, a quartz tube with an inner diameter of 1.5 mm is used to realize the sealing of gas and liquid in the micro reaction channel, control the reaction pressure in photocatalytic reactor 9 to be 0.5-5 bar, and control the light source output power to be 3-20 W and the wavelength to be 320-365 nm.

[0042] Three-way valve b10: used for mixing the solution after cathode electrolysis with alkane / haloalkane mixed gas, optimizing the composition of the material before reaction. Three-way valve b10 is connected with photocatalytic reactor 9, continuous flow reactor 11 and the cathode electrolyte outlet of membrane electrode electrolysis cell 3 respectively, and the material obtained after reaction from photocatalytic reactor 9 is mixed with the cathode electrolyte discharged from the cathode electrolyte outlet of membrane electrode electrolysis cell 3 in three-way valve b10;

[0043] Continuous flow reactor 11: under the conditions of controlled heating and flow, the sufficient conversion of reactants is promoted, and the generation of target product is realized. Continuous flow reactor 11 is a reactor with an inner diameter of 1.5-10 mm, and the material is PFA, glass or quartz. In this embodiment, a quartz tube with an inner diameter of 1.5 mm is selected as a microreactor, see Figure 3 , and is provided with a heating device, which can control the reaction temperature of continuous flow reactor 11 to be 60-100℃. Under the conditions of controlled light and flow, the sufficient conversion of reactants is promoted, and the optimization of photocatalytic reaction is realized.

[0044] Product collection tank 12: used for collecting alcohol products after reaction, ensuring the effective separation and storage of products.

[0045] The above device can be used for the preparation of alcohol by alkane conversion, including methane, ethane, propane and butane, etc. The following takes the photocatalytic coupling selective oxidation of methane to prepare methanol as an example for illustration:

[0046] Membrane electrode electrolysis cell 3 is the core component of the device for electrocatalytic reaction, and the cathode and anode electrolyte both use 5.4M NaCl, and the reaction is carried out at room temperature and normal pressure, and the current of 300mA / cm 2 is applied to control. After reaction, anode electrolyte (aqueous solution containing Cl2) and cathode electrolyte (NaOH solution) are obtained.

[0047] After mixing the anode electrolyte obtained by electrolysis of membrane electrode electrolysis cell 3 with the methane output by alkane gas cylinder 6 through three-way valve a7, the mixture is introduced into photocatalytic reactor 9, and the flow rate of the gas is 50mL / min, and the flow rate of the electrolyte is 5mL / min, and the pressure is 1bar. The methane / chloromethane mixed gas prepared after reaction from photocatalytic reactor 9 is mixed with the cathode electrolyte after reaction of membrane electrode electrolysis cell 3 in three-way valve b10. The mixed electrolyte / gas is introduced into continuous flow reactor 11 for heating, and the heating temperature is 80℃ in this embodiment. The product obtained by reaction is collected in product collection tank 12.

[0048] The product is mainly methanol by nuclear magnetic resonance hydrogen spectrum 1 (H NMR), and the yield of methanol is 1.6*10 8 μmol / g cath, Faradic efficiency 82% (current density 300 mA / cm 2 ), electrical energy utilization efficiency 69% (current density 300 mA / cm 2 ). Breakthroughs in all aspects of methanol yield, Faradic efficiency, and electrical energy utilization efficiency are achieved.

[0049] The above description of the embodiments is to facilitate the ordinary skilled in the art to understand and use the utility model. The person skilled in the art can obviously easily make various modifications to these embodiments, and the general principles described herein are applied to other embodiments without having to go through creative labor. Therefore, the utility model is not limited to the above embodiments, and the improvements and modifications made by the person skilled in the art according to the disclosure of the utility model without departing from the scope of the utility model should be within the protection scope of the utility model.

Claims

1. A cascade photoelectrocatalytic reactor device for the conversion of alkanes to alcohols, characterized in that, The application relates to a continuous flow reactor for alkane oxidation, which comprises an electro-catalytic reaction component, a photo-catalytic reaction component, an alkane gas bottle (6), a three-way valve a (7), a continuous flow reactor (11) and a product collection tank (12), wherein the electro-catalytic reaction component is connected with the photo-catalytic reaction component through a pipeline, and the three-way valve a (7) is arranged on the connecting pipeline; the three-way valve a (7) is further connected with the alkane gas bottle (6); the photo-catalytic reaction component is sequentially connected with the continuous flow reactor (11) and the product collection tank (12) through pipelines.

2. A cascade photoelectrocatalytic reactor device for the conversion of alkanes to alcohols according to claim 1, characterized in that, The electro-catalytic reaction component comprises a membrane electrode electrolysis cell (3) and a cathode liquid tank (1) and an anode liquid tank (2) connected with the membrane electrode electrolysis cell (3).

3. A cascade photoelectrocatalytic reactor device for the conversion of alkanes to alcohols according to claim 2, characterized in that, The membrane electrode electrolysis cell (3) comprises a proton exchange membrane and a cathode (4) and an anode (5) arranged on two sides of the proton exchange membrane; the cathode liquid tank (1) is connected with the cathode (4), and the anode liquid tank (2) is connected with the anode (5).

4. The cascade photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 2, characterized in that, The anode electrolyte outlet of the membrane electrode electrolysis cell (3) is connected with the three-way valve a (7).

5. The cascade photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 2, characterized in that, The electrolyte stored in the cathode liquid tank (1) and the anode liquid tank (2) is a NaCl, KCl, NaBr, KBr, NaI or KI solution.

6. The cascaded photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 1, wherein, The photo-catalytic reaction component comprises a light source and a photo-catalytic reactor (9).

7. The cascade photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 6, characterized in that, The outlet of the photo-catalytic reactor (9) is connected with the continuous flow reactor (11) through a pipeline, and the three-way valve b (10) is arranged on the connecting pipeline; the three-way valve b (10) is further connected with the electro-catalytic reaction component through a pipeline.

8. The cascade photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 6, characterized in that, The photo-catalytic reactor (9) is a transparent micro-channel with an inner diameter of 1.5-10 mm.

9. The cascade photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 6, characterized in that, The light source is an LED lamp, the output power of the LED lamp is 3-20 W, and the wavelength is 320-365 nm.

10. The cascaded photoelectrocatalytic reactor for the conversion of alkanes to alcohols according to claim 1, wherein, The continuous flow reactor (11) is a reactor with an inner diameter of 1.5-10 mm and made of PFA, glass or quartz.

Images