Abstract: The invention relates to a method for recycling educt-containing process gas (residual gas) in electrochemical processes with at least one gas diffusion electrode while using a gas jet pump for directly reintroducing the residual gas in the electrochemical process.

Abstract: An electrochemical cell comprising: (i) an anode half-cell with an anode, (ii) a cathode half-cell with a cathode, (iii) an ion-exchange membrane arranged between the anode half-cell and the cathode half-cell, the anode and/or the cathode comprising a gas diffusion electrode, (iv) a gap between the gas diffusion electrode and the ion-exchange membrane, (v) an electrolyte feed inlet above the gap, (vi) an electrolyte drain beneath the gap, (vii) a gas inlet, (viii) a gas outlet, and (ix) an electrolyte holding vessel comprising an overflow connected with the electrolyte feed inlet.

Abstract: The present invention describes an electrochemical cell, comprising at least an anode half-cell with an anode, a cathode half-cell with a cathode, and an ion exchange membrane arranged between the anode half-cell and the cathode half-cell, the anode and/or the cathode is a gas diffusion electrode. And a gap is provided between the gas diffusion electrode and the ion exchange membrane, and the half-cell with the gas diffusion electrode has an electrolyte feed and an electrolyte discharge as well as a gas inlet and a gas outlet. The electrochemical cell preferably has an electrolyte feed that is hermetically connected to the gap.

Abstract: The invention describes an electrochemical cell for the electrolysis of an aqueous solution of hydrogen chloride, comprising at least an anode half-cell with an anode, a cathode half-cell with a gas diffusion electrode as cathode and an ion exchange membrane arranged between the anode half-cell and the cathode half-cell, the membrane consisting of at least a perfluorosulfonic acid polymer, wherein the gas diffusion electrode and the ion exchange membrane are adjacent to each other, characterised in that the gas diffusion electrode and the ion exchange membrane, under a pressure of 250 g/cm2 and at a temperature of 60° C., have a contact area of at least 50%, with respect to the geometric area.

Abstract: The present invention describes an electrochemical half-cell, comprising a gas space, an electrolyte space and a gas diffusion electrode in the form of a cathode or anode. The gas diffusion electrode separates the gas space from the electrolyte space and comprises an electrically conductive substrate and an electrochemically active coating. The gas diffusion electrode includes a coating-free edge region and is connected to a support structure in the coating-free edge region via an electrically conductive plate, which covers at least the coating-free edge region as well as a coated edge region.

Abstract: A method is described for the electrolysis of an aqueous solution of hydrogen chloride or alkali metal chloride in an electrolysis cell. The cell includes at least of an anode half-element and an anode, a cathode half-element and a gas diffusion electrode as the cathode, and a cation exchange membrane for separating the anode half-element and the cathode half-element. A gas containing oxygen is supplied to the cathode half-element and excess gas containing oxygen is discharged from the cathode half-element. Excess gas containing oxygen discharged from the cathode half-element is subjected to catalytic oxidation of hydrogen.

Abstract: The invention relates to a method for recycling educt-containing process gas (residual gas) in electrochemical processes with at least one gas diffusion electrode while using a gas jet pump for directly reintroducing the residual gas in the electrochemical process.

Abstract: The present invention describes an electrochemical half-cell, comprising a gas space, an electrolyte space and a gas diffusion electrode in the form of a cathode or anode. The gas diffusion electrode separates the gas space from the electrolyte space and comprises an electrically conductive substrate and an electrochemically active coating. The gas diffusion electrode includes a coating-free edge region and is connected to a support structure in the coating-free edge region via an electrically conductive plate, which covers at least the coating-free edge region as well as a coated edge region.

Abstract: An electrolysis cell, suitable for the electrochemical production of chlorine from aqueous solutions of hydrogen chloride. The cell preferably comprises an anode space formed from an anode, an anode frame, and a back wall, the anode frame supporting the anode, and the anode space having an inlet and an outlet for the electrolyte, a cathode space formed from a current collector. The cell further preferably comprises a cathode frame and a back wall, the cathode frame supporting the current collector and the cathode space having an inlet and an outlet for the gas, a gas diffusion electrode arranged between anode and current collector and an cation exchange membrane arranged between anode and gas diffusion electrode, wherein the gas diffusion electrode is fixed on the current collector.

Abstract: Electrode at least comprising an electroconductive support of a titanium-palladium alloy, titanium, tantalum or compounds or alloys of titanium or of tantalum, an electrochemically active coating and an interlayer between the support and the electrochemically active coating, wherein the interlayer consists of titanium carbide and/or titanium boride and is applied to the support by flame or plasma spraying. Process for producing these electrodes and their use in an electrochemical cell for producing chlorine or chromic acid.

Abstract: The present invention discloses a process for the production of a gas diffusion electrode, in particular for the electrolysis of an aqueous solution of hydrogen chloride, in a first step a) a dispersion of a catalyst containing a noble metal and of a proton-conducting ionomer in an organic solvent being sprayed onto an electrically conductive support optionally provided with a coating material containing an acetylene black/polytetrafluoroethylene mixture and, in a second step b), the organic solvent being removed.

Abstract: The invention describes an electrochemical cell for the electrolysis of an aqueous solution of hydrogen chloride, comprising at least an anode half-cell with an anode, a cathode half-cell with a gas diffusion electrode as cathode and an ion exchange membrane arranged between the anode half-cell and the cathode half-cell, the membrane consisting of at least a perfluorosulfonic acid polymer, wherein the gas diffusion electrode and the ion exchange membrane are adjacent to each other, characterised in that the gas diffusion electrode and the ion exchange membrane, under a pressure of 250 g/cm2 and at a temperature of 60° C., have a contact area of at least 50%, with respect to the geometric area.

Abstract: A method for the electrolysis of aqueous solutions of hydrogen chloride in order to produce chlorine, characterized in that the following process parameters are maintained for initial operation: the anode half-element is filled with a 5 to 20% strength by weight hydrochloric acid, the concentration of the hydrochloric acid is more than 5% by weight during initial operation, the volumetric flow of the hydrochloric acid through the anode half-element is set in such a way that, at the start of electrolysis, the velocity of the hydrochloric acid in the anode space is from 0.05 cm/s to 0.15 cm/s, the electrolysis is started with a current density of 0.5 to 2 kA/m2, and the current density is then increased continuously or discontinuously until the desired current density is reached.

Abstract: The invention describes an electrochemical cell for the membrane electrolysis process for electrolyzers with single-element technology. The cell consists of at least of 2 half-shells (8, 10), which surround an anolyte chamber (16) and a cathode chamber (22) with a membrane (5) arranged in between, and an anode (6) in the anolyte chamber (16), with the cathode chamber (22) being provided with an oxygen-consuming cathode (4), with a plurality of pressure-compensated gas pockets (15) arranged one above the other, a catholyte gap (14) and optionally a back chamber (19), where electrically conducting supporting elements (7) are provided in the anolyte chamber (16) and supporting elements (3, 2, 1) are provided in the cathode chamber (22) at the same position opposite one another.

Abstract: An electrochemical cell comprising: (i) an anode half-cell with an anode, (ii) a cathode half-cell with a cathode, (iii) an ion-exchange membrane arranged between the anode half-cell and the cathode half-cell, the anode and/or the cathode comprising a gas diffusion electrode, (iv) a gap between the gas diffusion electrode and the ion-exchange membrane, (v) an electrolyte feed inlet above the gap, (vi) an electrolyte drain beneath the gap, (vii) a gas inlet, (viii) a gas outlet, and (ix) an electrolyte holding vessel comprising an overflow connected with the electrolyte feed inlet.

Abstract: The present invention describes an electrochemical half-cell, comprising a gas space, an electrolyte space and a gas diffusion electrode in the form of a cathode or anode. The gas diffusion electrode separates the gas space from the electrolyte space and comprises an electrically conductive substrate and an electrochemically active coating. The gas diffusion electrode includes a coating-free edge region and is connected to a support structure in the coating-free edge region via an electrically conductive plate, which covers at least the coating-free edge region as well as a coated edge region.

Abstract: An electrolysis cell, suitable for the electrochemical production of chlorine from aqueous solutions of hydrogen chloride. The cell preferably comprises an anode space formed from an anode, an anode frame, and a back wall, the anode frame supporting the anode, and the anode space having an inlet and an outlet for the electrolyte, a cathode space formed from a current collector. The cell further preferably comprises a cathode frame and a back wall, the cathode frame supporting the current collector and the cathode space having an inlet and an outlet for the gas, a gas diffusion electrode arranged between anode and current collector and an cation exchange membrane arranged between anode and gas diffusion electrode, wherein the gas diffusion electrode is fixed on the current collector.

Abstract: The invention describes a process for the electrolysis of an aqueous solution of alkali metal chloride, in particular sodium chloride, by the membrane process with an aqueous solution of alkali metal hydroxide, in particular sodium hydroxide, as catholyte, where the temperature of the alkali metal chloride solution in the anode half-element and/or the volume flow rate of the alkali metal chloride solution in the anode half-element are set in such a way that the difference between the temperature of the alkali metal hydroxide solution at the entry into the cathode half-element and the temperature of the alkali metal hydroxide solution at the exit from the cathode half-element are not greater than 15° C.

Abstract: The invention describes a structural unit for bipolar electrolysers according to the filter press technique, at least comprising a first half-shell, a second half-shell and a frame-shaped carrier element, in which at least one of the half-shells contains plastics material, the two half-shells are arranged within the carrier element so that the rear wall of the first half-shell and the rear wall of the second half-shell abut one another, the carrier element as well as the two half-shells have at least two openings for the inflow and outflow of electrolyte and/or gas, and the two half-shells have passages lying above one another in the floor for accommodating at least one electrically conducting connecting element, to which is secured in the first half-shell a first electrode and in the second half-shell a second electrode.

Abstract: The invention relates to a method for producing textile constructions for gas diffusion electrodes, particularly for use in electrolysis cells, according to which the textile construction is produced by rolling a dry power mixture containing at least one catalyst or one catalyst mixture and one binder. In a first preferred embodiment of the method, a liquid organic compound, particularly an alcohol, a ketone, an ester or a mixture of liquid organic compounds of this type is applied to the roll surfaces of the roll pair before bringing it into contact with the powder mixture, whereupon the roll surfaces are dried. In a second preferred embodiment, optionally in addition to the treatment of the roll surfaces with the liquid organic compound, ground powder made of polytetrafluoroethylene is rolled into a textile construction before rolling the dry power mixture.