Electrolytic bath runner structure capable of enhancing mass transfer

Abstract

The invention discloses a mass transfer enhanced electrolytic bath runner structure which comprises a runner field formed on a polar plate, the runner field is composed of a runner groove, a plurality of bottom rotational flow grooves are uniformly distributed in the bottom of the runner groove, and a plurality of side rotational flow grooves are uniformly distributed in the wall of the runner groove; the two ends of the bottom rotational flow groove are communicated with the side rotational flow grooves in the groove walls on the two sides. According to the flow channel structure of the electrolytic cell, laminar flow in a traditional flow channel can be changed into rotary torsional flow in a gun barrel rifling imitating flow channel under the condition of low flow speed, so that mass transfer of a bulk phase electrolyte to the surface of an electrode is enhanced, and the Faraday efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electrosynthesis and hydrogen production, and in particular relates to an electrolytic cell flow channel structure for enhancing mass transfer. Background Art

[0002] For the electrolysis of dilute substances in water, the mass transfer problem is one of the important factors limiting the industrial application of the electrolysis system. Therefore, analyzing the mass transfer limitation phenomenon in the electrolysis of dilute substances in water is crucial to promote the technical development and practical application of the electrolysis of dilute substances in water.

[0003] In electrocatalytic organic oxidation / reduction, nitrate reduction, carbon dioxide reduction and other reactions, the substrate concentration in the electrolyte is often low. After the electrolysis begins, the substrate on the electrode surface is consumed by the reaction and the concentration decreases. However, the mass transfer between the substrate and the electrode in the electrolytic liquid phase is poor, and the substrate molecules cannot fully contact the electrode surface, resulting in a slow reaction rate and side reactions on the electrode surface.

[0004] However, due to the limitation of single-pass conversion rate and ion exchange membrane, it is impossible to enhance convective mass transfer by increasing flow rate in electrochemical reactors. Therefore, designing a flow channel design that can change the flow mode in the flow channel under low flow rate conditions to enhance convective mass transfer is an urgent problem to be solved in this field. Summary of the invention

[0005] The present invention is proposed to overcome the shortcomings of the prior art, and its purpose is to provide an electrolytic cell flow channel structure that enhances mass transfer.

[0006] The present invention is achieved through the following technical solutions:

[0007] A flow channel structure of an electrolytic cell for enhancing mass transfer includes a flow channel field formed on an electrode plate, the flow channel field is composed of flow channel grooves, a plurality of bottom swirl grooves are evenly distributed on the bottom of the flow channel grooves, and a plurality of side swirl grooves are evenly distributed on the groove walls of the flow channel grooves; both ends of the bottom swirl grooves are connected to the side swirl grooves on the groove walls on both sides.

[0008] In the above technical solution, the groove cross-section of the bottom swirl groove and the side swirl groove is any one of a hexagon, a triangle or a semicircle.

[0009] In the above technical solution, the angle between the groove direction of the bottom swirl groove and the liquid flow direction is 5° to 85°.

[0010] In the above technical solution, the angle between the groove direction of the side swirl groove and the vertical direction is 5° to 85°.

[0011] In the above technical solution, the groove depths of the bottom swirl groove and the side swirl groove are both 0.05 to 0.5 times the groove depth of the flow channel groove.

[0012] In the above technical solution, the width of the bottom swirl groove is 0.1 to 2 times the depth of the bottom swirl groove; the width of the side swirl groove is 0.1 to 2 times the depth of the side swirl groove.

[0013] In the above technical solution, the vertical distance between adjacent groove walls of two adjacent bottom swirl grooves is 0.5 to 3 times the groove width of the bottom swirl groove.

[0014] In the above technical solution, the vertical distance between adjacent groove walls of two adjacent side swirl grooves is 0.5 to 3 times the groove width of the side swirl groove.

[0015] In the above technical solution, the groove depth of a single flow channel groove is 0.5 mm to 5 mm; the groove width of a single flow channel groove is 0.5 mm to 5 mm.

[0016] In the above technical solution, the length and width of the square area where the flow field is located are both 10 mm to 500 mm.

[0017] In the above technical solution, the flow field is Figure 2 Any of the single-channel serpentine flow field, straight-channel parallel flow field, multi-channel serpentine flow field, mixed serpentine flow field or cross-finger flow field shown.

[0018] In the above technical solution, when the flow channel field is a single-channel serpentine flow channel field, the flow channel field is a square area composed of a serpentine-shaped winding flow channel groove;

[0019] When the flow channel field is a multi-channel serpentine flow channel field, the flow channel field is a square area composed of a plurality of serpentine-shaped flow channel grooves, and the plurality of flow channel grooves are parallel to each other;

[0020] When the flow channel field is a straight channel parallel flow channel field, the flow channel field is a square area composed of a plurality of parallel linear flow channel grooves;

[0021] When the flow channel field is a mixed serpentine flow channel field, the flow channel field is a square area composed of a plurality of serpentine winding flow channels and parallel straight flow channels arranged in a mixed manner;

[0022] When the flow channel field is a cross-finger flow channel field, the flow channel field is a directional structure composed of two groups of cross-shaped flow channel grooves, the cross-shaped flow channel grooves are composed of a horizontal groove and multiple vertical grooves perpendicular to the horizontal grooves, the multiple vertical grooves are arranged at intervals, and the vertical grooves of one group of cross-shaped flow channel grooves are inserted into the gap between the two vertical grooves of another group of cross-finger flow channel grooves; the liquid inlet end and liquid outlet end flow channels of the cross-finger flow channel field are not connected to each other and the finger shape is crossed.

[0023] An electrolytic cell has the above-mentioned electrolytic cell flow channel structure for enhancing mass transfer; the material of the electrode plate is selected from any one of titanium, stainless steel, nickel or graphite; the central reaction area of ​​the electrode plate is 10cm×10cm.

[0024] A reactor comprises the electrode plate mentioned above.

[0025] The beneficial effects of the present invention are:

[0026] The present invention provides an electrolytic cell flow channel structure for enhancing mass transfer, which can transform the fluid from laminar flow in a traditional flow channel to a rotational torsional flow in a gun barrel rifling flow channel under low flow rate conditions to enhance the mass transfer of bulk electrolyte to the electrode surface, thereby improving the Faraday efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the electrode plate having the electrolytic cell flow channel structure for enhancing mass transfer of the present invention;

[0028] Figure 2 Schematic diagrams of the structures of five flow channel fields involved in the present invention (a, single-channel serpentine flow channel field; b, straight-channel parallel flow channel field; c, multi-channel serpentine flow channel field; d, mixed serpentine flow channel field; e, cross-finger flow channel field);

[0029] Figure 3 This is a comparison diagram of the Faradaic efficiency, yield, selectivity and productivity of coupled hydrogen production by oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) at different current densities in an electrochemical reactor using the flow channel structure of the present invention and an electrochemical reactor using a traditional flow channel structure in Example 2 of the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of the electrode plate using a traditional flow channel structure.

[0031] 1. Pole plate; 2. Flow channel groove; 3. Inlet groove; 4. Outlet groove; 5. Bottom swirl groove.

[0032] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0034] Example 1

[0035] A flow channel structure of an electrolytic cell for enhancing mass transfer, comprising a flow channel field formed on an electrode plate, wherein the flow channel field is a multi-channel serpentine flow channel field, and the multi-channel serpentine flow channel field is a square structure composed of a plurality of serpentine-shaped winding flow channel grooves 2; the plurality of flow channel grooves 2 are parallel to each other;

[0036] The flow channel 2 is composed of a plurality of horizontal sections and a plurality of vertical sections, and the vertical sections are arranged at the bends of the flow channel 2;

[0037] The bottom of the horizontal section of the flow channel groove 2 is evenly distributed with a plurality of spaced bottom swirl grooves 5, and the groove wall of the horizontal section of the flow channel groove 2 is evenly distributed with a plurality of spaced side swirl grooves, and the two ends of the bottom swirl groove are connected with the side swirl grooves on the groove walls on both sides;

[0038] The groove cross-section of the bottom swirl groove 5 and the side swirl groove is a semicircle with a radius of 0.2 mm.

[0039] The angle between the groove direction of the bottom swirl groove 5 and the liquid flow direction is 45°;

[0040] The angle between the slotting direction of the side swirl groove and the vertical direction is 45°;

[0041] The groove depths of the bottom swirl groove 5 and the side swirl grooves are both 0.2 mm;

[0042] The groove widths of the bottom swirl groove 5 and the side swirl grooves are both 0.5 mm;

[0043] The vertical distance between the adjacent groove walls of two adjacent bottom swirl grooves 5 is 0.5 mm;

[0044] The vertical distance between adjacent groove walls of two adjacent side swirl grooves is 0.5 mm;

[0045] The groove depth of the flow channel groove is 1 mm;

[0046] The groove width of the flow channel groove is 2mm;

[0047] The total length of the flow channel along the liquid flow direction is 100 mm;

[0048] The liquid inlet and the liquid outlet of the flow channel 2 are arranged diagonally;

[0049] An inlet groove 3 is provided at the front end of the liquid inlet of the flow channel groove 2, and the inlet groove 3 is connected with the liquid inlet of the plurality of flow channel grooves 2, and the inlet groove 3 is connected with the liquid inlet of the electrode plate 1;

[0050] The outlet end of the flow channel groove 2 is provided with an outlet groove 4; the outlet groove 4 is connected with the outlets of the plurality of flow channel grooves 2, and the outlet groove 4 is connected with the outlet of the electrode plate 1;

[0051] The inlet slot 3 and the outlet slot 4 are both arranged vertically;

[0052] The material of the electrode plate 1 is titanium, and the central reaction area covered by the flow channel is 10 cm×10 cm.

[0053] Example 2

[0054] An electrolytic cell, wherein the anode plate has the electrolytic cell flow channel structure for enhancing mass transfer as described in Example 1;

[0055] An electrolytic cell was assembled with nickel electrodeposited on nickel foam as anode and ruthenium oxide sprayed on anion exchange membrane as membrane electrode cathode, and an experiment was carried out on electrocatalytic oxidation of HMF to produce FDCA under alkaline conditions.

[0056] The electrolyte was 1.5 M KOH, the HMF concentration was 300 mM, the flow mode was one-way flow, and the test was carried out under constant current conditions with current densities of 400, 500, and 600 mA cm -2 .

[0057] In the electrolytic cell equipped with the traditional flow channel structure, the conversion rates at three current densities were 88.45%, 81.89%, and 81.89%, respectively; in the electrolytic cell equipped with the flow channel structure of the present invention, the conversion rates at three current densities were 88.45%, 88.32%, and 86.05%, respectively.

[0058] Use with Figure 4 The specific numerical comparisons of the conversion rate, Faraday efficiency, yield, selectivity and productivity of 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA) coupled hydrogen production at different current densities in an electrochemical reactor with a conventional plate having a flow channel structure as shown and an electrochemical reactor with a plate having a flow channel structure of the present invention are shown in Tables 1 and Figure 3 ;

[0059] Table 1

[0060]

[0061] As can be seen from Table 1, the Faraday efficiency (>88%), yield (>81%), selectivity (>88%) and productivity of FCDA in the electrolyzer equipped with the flow channel structure of the present invention are significantly higher than those in the electrolyzer equipped with the traditional flow channel structure. Figure 3 The data show that the FDCA Faradaic efficiency, selectivity and yield at the same current density in the reactor using the flow channel structure of the present invention are higher, proving the superiority of the present invention over the traditional flow channel structure.

[0062] Example 3

[0063] An electrolytic cell, wherein the cathode plate has the electrolytic cell flow channel structure for enhancing mass transfer as described in Example 1;

[0064] An electrolytic cell was assembled with oxidized copper foam as cathode, nickel electrodeposited on nickel foam as anode and an anion exchange membrane as diaphragm, and an experiment was carried out on electrocatalytic reduction of HMF to produce 2,5-furan dimethanol (BHMF) under alkaline conditions.

[0065] The electrolyte was 1.5 M KOH, the HMF concentration was 300 mM, the flow mode was one-way flow, and the test was carried out under constant current conditions with current densities of 400, 500, and 600 mA cm -2 .

[0066] In the electrolytic cell equipped with the traditional flow channel structure, the conversion rates at three current densities are 85.23%, 79.52%, and 79.69%, respectively; in the electrolytic cell equipped with the flow channel structure of the present invention, the conversion rates at three current densities are 88.65%, 88.44%, and 87.07%, respectively.

[0067] The Faraday efficiency (>87%), yield (>81%), selectivity (>89%) and productivity of BHMF in the electrolyzer equipped with the flow channel structure of the present invention are significantly higher than those of the electrolyzer equipped with the traditional flow channel structure, proving the superiority of the present invention over the traditional flow channel structure.

[0068] Example 4

[0069] An electrolytic cell, wherein the cathode plate has the electrolytic cell flow channel structure for enhancing mass transfer as described in Example 1;

[0070] The electrolytic cell was assembled with oxidized copper foam as cathode, nickel electrodeposited on nickel foam as anode, and anion exchange membrane as diaphragm to electrocatalyze nitrate (NO 3 - ) reduction to produce ammonia (NH 3 ) experiment.

[0071] The electrolyte is 1.5M KOH, KNO 3 The concentration was 300 mM, the flow mode was one-way flow, and the test was carried out under constant current conditions with current densities of 400, 500, and 600 mA cm -2 .

[0072] In the electrolytic cell equipped with the traditional flow channel structure, the conversion rates at three current densities are 88.77%, 80.43%, and 79.98%, respectively; in the electrolytic cell equipped with the flow channel structure of the present invention, the conversion rates at three current densities are 88.96%, 88.32%, and 87.12%, respectively.

[0073] The electrolytic cell equipped with the flow channel structure of the present invention contains NH 3The Faradaic efficiency (>89%), yield (>83%), selectivity (>88%) and productivity are significantly higher than those of the electrolyzer equipped with a traditional flow channel structure, proving the superiority of the present invention over the traditional flow channel structure.

[0074] Working principle of the present invention:

[0075] The mass transfer-enhanced electrolytic cell flow channel structure of the present invention has grooves with a certain angle to the flow channel direction processed on the bottom and side surfaces of the electrolytic cell flow channel, so that a gun barrel rifling structure is presented in the electrolytic cell, which is similar to the gun barrel rifling causing the bullet to rotate. The electrolytic cell flow channel structure can force the electrolyte to transform from laminar flow in the traditional flow channel to rotational torsional flow under low Reynolds number conditions. The bottom surface grooves in the flow channel have the function of changing the laminar flow to torsional flow, and the side surface grooves can enhance the flow velocity on the catalyst surface, thereby enhancing the mass transfer from the substrate electrolytic liquid to the catalyst surface of the electrode, thereby achieving higher Faraday efficiency, substrate conversion rate and product yield.

[0076] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0077] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0078] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0079] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. An electrolytic cell flow channel structure for enhancing mass transfer, characterized in that: It includes a flow channel field formed on the electrode plate, the flow channel field is composed of at least one flow channel groove, a plurality of bottom swirl grooves are evenly distributed on the bottom of the flow channel groove, and a plurality of side swirl grooves are evenly distributed on the groove wall of the flow channel groove; the two ends of the bottom swirl groove are connected with the side swirl grooves on the groove walls on both sides.

2. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: The groove cross-sections of the bottom swirl groove and the side swirl groove are any one of hexagonal, triangular or semicircular.

3. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: The angle between the groove direction of the bottom swirl groove and the liquid flow direction is 5° to 85°; the angle between the groove direction of the side swirl groove and the vertical direction is 5° to 85°.

4. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: The groove depths of the bottom swirl groove and the side swirl groove are both 0.05 to 0.5 times the groove depth of the flow channel groove; the groove width of the bottom swirl groove is 0.1 to 2 times the groove depth of the bottom swirl groove; the groove width of the side swirl groove is 0.1 to 2 times the groove depth of the side swirl groove.

5. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: The vertical distance between the adjacent groove walls of two adjacent bottom swirl grooves is 0.5 to 3 times the groove width of the bottom swirl groove; the vertical distance between the adjacent groove walls of two adjacent side swirl grooves is 0.5 to 3 times the groove width of the side swirl groove.

6. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: The groove depth of the flow channel groove is 0.5mm-5mm; the groove width of the flow channel groove is 0.5mm-5mm; the length and width of the square area where the flow channel field is located are both 10mm-500mm.

7. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: The flow channel field is any one of a single-channel serpentine flow channel field, a straight-channel parallel flow channel field, a multi-channel serpentine flow channel field, a mixed serpentine flow channel field or a cross-finger flow channel field.

8. The electrolytic cell flow channel structure for enhancing mass transfer according to claim 1, characterized in that: When the flow channel field is a single-channel serpentine flow channel field, the flow channel field is a square area consisting of a serpentine-shaped winding flow channel groove; When the flow channel field is a multi-channel serpentine flow channel field, the flow channel field is a square area composed of a plurality of serpentine-shaped flow channel grooves, and the plurality of flow channel grooves are parallel to each other; When the flow channel field is a straight channel parallel flow channel field, the flow channel field is a square area composed of a plurality of parallel linear flow channel grooves; When the flow channel field is a mixed serpentine flow channel field, the flow channel field is a square area composed of a plurality of serpentine winding flow channels and parallel straight flow channels arranged in a mixed manner; When the flow channel field is a cross-finger flow channel field, the flow channel field is a directional structure composed of two groups of cross-shaped flow channel grooves, the cross-shaped flow channel grooves are composed of a horizontal groove and multiple vertical grooves perpendicular to the horizontal grooves, the multiple vertical grooves are arranged at intervals, and the vertical grooves of one group of cross-shaped flow channel grooves are inserted into the gap between the two vertical grooves of another group of cross-finger flow channel grooves; the liquid inlet end and liquid outlet end flow channels of the cross-finger flow channel field are not connected to each other and the finger shape is crossed.

9. An electrode plate, characterized in that: An electrolytic cell flow channel structure with enhanced mass transfer as claimed in any one of claims 1 to 8.

10. An electrolytic cell, characterized in that: A electrode plate according to claim 9.

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