RU2211885C1 - Electrochemical facility - Google Patents

Abstract

FIELD: production of oxygen and hydrogen by method of water electrolysis. SUBSTANCE: given electrochemical facility is of filter- press type. Electrochemical cells separated by plate 7 are located between end plates 1. Damping current taps 3, electrodes 4, 5 and solid polymer electrolyte 6 separating them are installed in sealing frames 2. Holes 12, 14, 16, 18 forming conduits 17, 19 to feed reagents and 13, 15 to discharge reaction products are made in end plates 1, sealing frames 2 and solid polymer electrolyte 6. Slit grooves 8, 9, 10, 11 reinforced with inserts 20 join electrode working zones with conduits 17, 19 to feed reagents and with conduits 13, 15 to discharge reaction products. Slit groove 8, 9, 10, 11 are made in sealing frames 2 and have width less than width of frame. EFFECT: decreased usage of materials and technological expenses. 3 dwg, 1 tbl

Description

 The invention relates to electrochemical devices of a filter-press type and can be used, for example, to produce hydrogen and oxygen of high purity by water electrolysis.

A filter-press type electrolyzer is known, including end plates, between which at least a pair of electrochemical electrically connected cells are located, including down conductors, electrodes and solid-polymer electrolyte separating electrodes, which form electrode work areas assembled (Patent for invention 2041291, RF, published 09.08.1995, IPC ⁶ 25 V 9/00. Electrolyzer). The electrolyzer contains a distribution device for supplying reagents and removal of reaction products, placed between adjacent electrochemical cells.

 The disadvantage of this cell is the complexity of the design as a whole and the high metal consumption of the structural elements: down conductors and switchgear.

The closest technical solution to the claimed device is an electrochemical filter-press type device, including end plates, between which at least a pair of sealing frames with damping current collectors and electrodes installed in them and a solid polymer electrolyte separating the electrodes forming the electrode working zones . Openings are made in the end plates, sealing frames and in the solid polymer electrolyte, which form complete channels for supplying reagents and removing reaction products (Utility Model Certificate 22308, Russian Federation, publ. March 20, 2002, IPC ⁷ C 22 V 9/00. Electrochemical device )

 The electrode working zones, the anode and cathode, are connected to the corresponding channels for the removal of the reaction product and the supply of the reagent by means of distribution devices located between the end plates and adjacent cells. Distribution devices include separation plates with coaxial holes and openings for communication with the anode and cathode and elastic gaskets of insulating material, each with four windows with slotted channels, sandwiched between the separation plates or separation plates and end plates.

 A significant drawback of the described design is its lack of manufacturability due to the large number of parts and operations used in the manufacture and assembly of structural elements of switchgears and the electrochemical device as a whole.

 The inventors had the task of simplifying the design of the electrochemical device, reducing material consumption and technological costs while maintaining the operational and technical characteristics of the device.

 This object is achieved in that in an electrochemical device of a filter-press type, including end plates, between which at least a pair of sealing frames are installed with damping current leads and electrodes installed in them and a solid polymer electrolyte separating the electrodes, which form the electrode working zones, with holes made in the end plates, sealing frames and in the solid polymer electrolyte, forming complete channels for supplying reagents and removal of reaction products to the seal On the opposite side from the electrolyte side, slotted grooves are made connecting each electrode working area with corresponding channels for withdrawing the reaction product and supplying the reagent, while slotted grooves are not made over the entire thickness of the frame and are reinforced with inserts.

 Thus, in the claimed technical solution, the switchgear is formed inside the electrochemical cell. The sealing frame in this technical solution combines several functions at the same time: sealing the electrode working areas and the design of the device as a whole, forming the volume of the electrode working area in which the electrochemical reaction proceeds, and creating a transport stream between the channels for supplying reagents to the electrode working areas and removal of reaction products from them.

 The execution in the sealing frames on the opposite side of the electrolyte of the slit grooves connecting each electrode working area with the corresponding channels for the removal of the reaction product and the supply of the reagent, allows you to form a switchgear inside the cell and as a result to abandon a large number of parts and operations used in the manufacture and assembly elements of the known design of the switchgear and the electrochemical device as a whole.

 Performing slotted grooves not across the entire thickness of the frame and reinforcing them with inserts allows simultaneously with an increase in the manufacturability of the electrochemical device to ensure reliable removal of reaction products and reagent supply to the working electrode zones and to maintain the operational and technical characteristics of the filter-press type electrochemical device due to the rigidity of the structure, preservation of the flatness of the electrodes during operation of the device, uniform current distribution over the solid polymer electrolyte.

 Preserving the integrity of the sealing frames on the side of the solid polymer electrolyte due to the implementation of slotted grooves not across the entire thickness of the frame and their reinforcement with inserts allows preserving the flatness of the solid polymer electrolyte and tightness of the structure under pressure drops between the anode and cathode working zones, preventing the reaction products from flowing from one zone to another .

 The proposed gap connection of the electrode working areas with the corresponding channels for the removal of the reaction product and the supply of the reagent reduces the transient resistance by reducing the structural elements of the switchgear and improving the electrical contact between the collectors and electrodes.

 In the inventive device, the integrity of the solid polymer electrolyte is ensured by equalizing the mechanical effects on the electrolyte and eliminating electrical breakdowns in the electrode working areas.

 The specified set of distinctive features indicates the conformity of the claimed electrochemical device to the criterion of "novelty."

 The positive effect of the claimed design, expressed in reducing material consumption and technological costs for the manufacture of the device while maintaining its operational and technical characteristics, does not follow explicitly from the specified set of essential features, which indicates the compliance of the claimed technical solution with the criterion of "inventive step".

 The claimed device solves all the main technological problems of creating electrochemical devices of a filter-press type: tightness, preservation of the volume of electrode working zones, reliable electrical contacts, organization of the supply of reagents and removal of reaction products, maintaining the integrity of the solid polymer electrolyte during operation.

 The extreme simplicity of the design and its operational reliability make it possible to consider the question of optimizing the design of this type of device practically resolved and shift the attention on improving electrochemical devices to the problems of electrochemistry.

 The invention is illustrated by drawings and a description of the design of the claimed electrochemical device of a filter-press type.

 In FIG. 1 is a perspective view of an electrochemical device consisting of two electrochemical cells connected electrically in series and hydraulically in parallel. Figure 2 shows in isometric sealing frame with slotted grooves. Figure 3 shows the reinforcing insert of the slotted groove.

 The electrochemical device of the filter-press type consists of end plates 1, between which sealing frames are placed 2. Within 2, damping down conductors 3 and electrodes are installed, some of which serve as anodes 4 and others as cathodes 5. Anode 4 and cathode 5 are separated by a solid polymer electrolyte 6. The sealing frame 2, the collector 3 and the anode 4, limited on one side by the end plate 1, and on the other by the solid polymer electrolyte 6, form an electrode (anode) working area. The sealing frame 2, the collector 3 and the cathode 5, limited on the one hand by the same solid polymer electrolyte 6, and on the other hand by the dividing plate 7, form an electrode (cathode) working area. The separation plate 7 performs the function of the end plate for a separate electrochemical cell and the function of the separation plate in a device consisting of two electrochemical cells connected electrically in series and hydraulically in parallel. An increase in the number of electrochemical cells between the end plates increases the productivity of the electrochemical process by increasing the total area of the electrode working zones, and their number is the result of a compromise between the productivity of the electrochemical device (the number of reaction products per unit time) and the life of the device as a whole.

 In the sealing framework 2, slotted grooves 8, 9, 10 and 11 are made on the opposite side from the electrolyte 6.

 In the end plates 1, in the sealing frame 2 and in the solid polymer electrolyte 6, coaxial openings 12 are formed, which form a channel 13 for removing the reaction product through the slot groove 10 from the cathode working zone, for example, hydrogen during electrolysis of water.

 In the end plates 1, in the sealing frame 2 and in the solid polymer electrolyte 6, coaxial holes 14 are made which form a channel 15 for removing the reaction product through the slot groove 9 from the anode working zone, for example, oxygen.

 In the end plates 1, in the sealing frame 2 and in the solid polymer electrolyte 6, coaxial holes 16 are formed that form the channel 17, and holes 18 that form the channel 19 are used to supply reagents through slotted grooves 8 and 11 to both electrode working areas, for example for water supply.

 The slotted grooves 8, 9, 10, 11 (see FIG. 2) are not made to the entire thickness of the frame 2 and are reinforced with inserts 20 (see FIG. 3).

 In the end plates 1, in the sealing frame 2, in the solid polymer electrolyte 6 and in the separation plate 7, coaxial holes 21 are made (see FIG. 2) for assembling the device elements into a single filter-press type structure.

 End plates 1 have overall dimensions, for example, in height, width and length, respectively 90, 70 and 10 mm, and are made of titanium VT 1-0 GOST 23755-79.

 The sealing frame 2 is made of a mixture of rubber 51-1742NTA TU 38405584-85 with overall dimensions of 90, 70 and 3 mm (see figure 2).

 The damping down conductors 3 are made of a profiled volumetric mesh formed of titanium sheet VT 1-0-0.2 OST 196027-71 with a thickness of 0.2 mm. The grid is a volume relief surface with a height of 2-2.2 mm with intermittent channels formed inside, and all the channels in the gap are offset relative to each other by 1/3 of the channel profile length, forming openings that provide a strong connection between the channels.

 The vertices of the mesh profile provide reliable conductive contact with the electrodes 4 and 5, on the one hand, and on the other hand, with end plates 1 and dividing plate 7.

 The discontinuous channels of the network form a flow of reagents, such as water, and the output of reaction products, such as oxygen and hydrogen. Longitudinal intermediate grooves between the profiles help to equalize the pressure of the reactants and reaction products in all channels, redistributing the pressure through the slots between the profiles, which eliminates possible local drying out or the formation of standing bubbles, providing water and gas exchange.

 The damping down conductors 3 are located in an electrochemical device, for example, in such a way that the guides of the discontinuous channels of the grid are perpendicular to the reagent flow in the electrode working zones.

 The electrodes, some of which serve as anodes 4, and others as cathodes 5, are made of porous titanium PPT-EM-MP-0.8 TU 14-1-1895-76 and have geometric sizes 50, 50 and 0.8-1, 0 mm From the side of the solid polymer electrolyte, the electrodes have coatings: anode 4 - a coating of platinum and iridium, cathode 5 - a coating of platinum black. Coating materials are catalysts for the effective conduct of an electrochemical reaction, for example, in the electrolysis of water.

 Solid polymer electrolyte 6 is a membrane of the type MF-4sk-4 TU 6-05-041-944-87 with a thickness of 0.2 mm and overall dimensions of 90 and 70 mm.

 The separation plate 7 is made of titanium sheet VT 1-0-0.8 GOST 22178-76 and has dimensions of 90, 70 and 0.8 mm.

 In the sealing frames 2, slotted grooves 8, 9, 10 and 11 are made with a depth of 2 mm and a width of 6 mm on the opposite side from the electrolyte 6. The slotted grooves are reinforced with inserts from titanium sheet VT 1-0-0.5 GOST 22178-76 with a thickness of 0.5 mm over the entire generatrix of the slotted groove.

 In the end plates 1, in the sealing frame 2, in the solid polymer electrolyte 6 and in the separation plate 7, coaxial holes 12, 14, 16 and 18 are made with a diameter of 8 mm, which assembled to form channels 13, 15, 17 and 19 for the removal of reaction products, for example hydrogen (channel 13) and oxygen (channel 15), from the electrode working areas and for supplying reagent (channels 17 and 19), for example, water.

 The coaxial holes 21 in the end plates 1, in the sealing frames 2, in the solid polymer electrolyte 6 and in the separation plate 7 have a diameter of 11 mm and are used to assemble the device into a single filter press type design using bolts and nuts.

The inventive electrochemical device of the filter-press type operates as follows, for example, in the electrolysis of water. In the anode working zone, under the influence of an electric field in the presence of catalysts, the water coming from the channel 19 through the slot groove 11 undergoes dissociation of H ₂ O <----> 2H ⁺ + O ^-2 . Hydrated cations (H ^{+ +} n • H ₂ O) penetrate through the solid polymer electrolyte into the cathode 6, a working area where a catalyst formed hydrogen 2H ^{+ +} 2e ^{- ->} H _2, which water flow entering the cathode working area of the channel 17 through the slot groove 8, is discharged through the slot groove 10 into the channel 13. Anions O ^-2 (the result of dissociation of water) in the anode working zone form oxygen 2O ^-2 -4e -> O ₂ , which ^is diverted by the water flow through the slot groove 9 into channel 15.

 FSUE NII NPO Luch manufactured pilot batches of a modular series of the claimed electrochemical devices for electrolysis of water to produce hydrogen and oxygen. The modifications differ in the number of electrochemical cells from 1 to 18 with a working size of electrode zones of 50x50 mm, power consumption from 0.020 to 0.688 kW and with a productivity of hydrogen from 5 to 124 l / h and oxygen from 2.5 to 62 l / h.

Comparative data on the operational and technical characteristics of the known device adopted for the prototype, and the inventive device for the production of hydrogen and oxygen by electrolysis of distilled water (specific resistance is more than 10 ⁶ Ohm • cm) are given in the table.

 Compared with the well-known design of an electrochemical device adopted as a prototype and manufactured by FSUE "Research Institute of NPO" Luch "in series, the inventive filter-type electrochemical device is characterized by a significant simplification of the design, a reduction in the average material consumption of the device as a whole to 30%, and reduction of technological costs to 40% while maintaining the operational and technical characteristics of the device.

 Conducted by FSUE "Scientific Research Institute of NPO" Luch "for 1 year and ongoing comparative tests of commercially available electrochemical devices adopted as a prototype, and the claimed device show a steady trend in superior operational and technical characteristics of the claimed device with a significant simplification of the design of the claimed electrochemical device, reducing material consumption and technological costs in its manufacture.

Claims (1)

 An electrochemical device of a filter-press type, including end plates, between which at least a pair of sealing frames with damping current conductors and electrodes installed in them and a solid polymer electrolyte separating the electrodes, forming electrode working zones in assembly, are installed in the end plates, sealing Within the framework and in the solid polymer electrolyte, holes are made that form complete channels for supplying reagents and for removing reaction products, characterized in that in the sealing frames with otivopolozhnoy formed on the electrolyte side of the slit grooves connecting each electrode working zone with respective ducts for discharging the reaction product and reactant feed, wherein the slotted recesses are not formed on the entire thickness of the reinforced frame and inserts.

Images