The invention relates to a process for controlling an electrolyzer. Determination of four different electrolyte flow rates at certain positions in the electrolyzer makes it possible to determine a compensation flow rate which establishes a fluidic connection between the anode side and the cathode side of the electrolyzer. The compensation system makes it possible to achieve at least partial concentration compensation between the electrolyte concentration on the anode side and the electrolyte concentration on the cathode side. The compensation flow rate makes it possible to draw conclusions about the operating state of the electrolyzer. The compensation flow rate makes it possible to determine a permeation flow rate between the anode space and the cathode space of one or more electrolysis cells. The permeation flow rate is correlated with a predetermined differential pressure between the anode space and the cathode space which improves the efficiency of the electrolyzer.

The invention relates to a process for controlling an electrolyzer. Determination of four different electrolyte flow rates at certain positions in the electrolyzer makes it possible to determine a compensation flow rate which establishes a fluidic connection between the anode side and the cathode side of the electrolyzer. The compensation system makes it possible to achieve at least partial concentration compensation between the electrolyte concentration on the anode side and the electrolyte concentration on the cathode side. The compensation flow rate makes it possible to draw conclusions about the operating state of the electrolyzer. The compensation flow rate makes it possible to determine a permeation flow rate between the anode space and the cathode space of one or more electrolysis cells. The permeation flow rate is correlated with a predetermined differential pressure between the anode space and the cathode space which improves the efficiency of the electrolyzer.

A flow cell for reducing carbon dioxide may include a first chamber having a gold coated gas diffusion layer working electrode, a reference electrode, and a water-in-salt electrolyte comprising a super concentrated aqueous solution of lithium bis-(trifluoromethanesulfonyl)imide (LiTFSI). A second chamber adjacent the first chamber has a gold coated gas diffusion layer counter electrode and the water-in-salt electrolyte. The second chamber being separated from the first chamber by a proton exchange membrane. A reservoir coupled to each of the first and the second chambers with a pump contains a volume of the water-in-salt electrolyte and a head space.

A method for operating a water electrolyzer includes applying a voltage to a water electrolysis cell such that a current having a target current value flows through the water electrolysis cell and stopping the current that flows through the water electrolysis cell upon a voltage applied to the water electrolysis cell being increased to a predetermined threshold value or more when a water electrolysis reaction is performed.

A method for operating a water electrolyzer includes applying a voltage to a water electrolysis cell such that a current having a target current value flows through the water electrolysis cell and stopping the current that flows through the water electrolysis cell upon a voltage applied to the water electrolysis cell being increased to a predetermined threshold value or more when a water electrolysis reaction is performed.

A method of operating a solid oxide electrolysis cell (SOEC) system at partial load, where the SOEC system includes a plurality of branches electrically connected in parallel, and each branch includes at least one SOEC stack. The method includes determining a thermally neutral target voltage below which operation is endothermic and above which operation is exothermic; and executing pulse width modulation current control by cycling an ON phase and an OFF phase for each branch such that the SOEC system operates at an average operating power equal to a chosen percentage of the operating power at the thermally neutral target voltage. In the ON phase, all of the SOEC stacks in a branch operate at the thermally neutral target voltage, and in the OFF phase, all of the SOEC stacks in the branch operate at 0% power. Each branch is configured to be operated independently of the other branches.

Large scale exploitation of Solar energy is proposed by using floating devices which use solar energy to produce compressed hydrogen by electrolysis of deep sea water. Natural ocean currents are used to allow the devices to gather solar energy in the form of compressed hydrogen from over a large area with minimum energy transportation cost. The proposal uses a combination of well understood technologies, and a preliminary cost analysis shows that the hydrogen produced in this manner would satisfy the ultimate cost targets for hydrogen production and pave the way for carbon free energy economy.

Large scale exploitation of Solar energy is proposed by using floating devices which use solar energy to produce compressed hydrogen by electrolysis of deep sea water. Natural ocean currents are used to allow the devices to gather solar energy in the form of compressed hydrogen from over a large area with minimum energy transportation cost. The proposal uses a combination of well understood technologies, and a preliminary cost analysis shows that the hydrogen produced in this manner would satisfy the ultimate cost targets for hydrogen production and pave the way for carbon free energy economy.

An electrolysis cell 20 includes: a cathode 31 to reduce a reducible gas; an anode 41 to oxidize an oxidizable substance in an electrolytic solution, the cathode 41 containing titanium; and a separator 50 separating the cathode 31 from the anode 41. The separator 50 includes a porous membrane. The porous membrane gives a pore size distribution defined by a graph having a horizontal axis and a vertical axis, the horizontal axis representing pore sizes of through holes of the porous membrane, the pore sizes being determined by using a porometer, the vertical axis representing a pore size flow distribution of pore volumes corresponding to the pore sizes, and the pore size distribution having a peak top in a range of not less than 0.01 m nor more than 0.3 m. The porous membrane has an ISO air permeance of not less than 0.8 m/Pa.Math.s nor more than 150 m/Pa.Math.s.

An electrolysis cell 20 includes: a cathode 31 to reduce a reducible gas; an anode 41 to oxidize an oxidizable substance in an electrolytic solution, the cathode 41 containing titanium; and a separator 50 separating the cathode 31 from the anode 41. The separator 50 includes a porous membrane. The porous membrane gives a pore size distribution defined by a graph having a horizontal axis and a vertical axis, the horizontal axis representing pore sizes of through holes of the porous membrane, the pore sizes being determined by using a porometer, the vertical axis representing a pore size flow distribution of pore volumes corresponding to the pore sizes, and the pore size distribution having a peak top in a range of not less than 0.01 m nor more than 0.3 m. The porous membrane has an ISO air permeance of not less than 0.8 m/Pa.Math.s nor more than 150 m/Pa.Math.s.