System requirement

- The system shall be able to produce caustic soda (typically 30-32%).

Physical requirements

- Temperature: 80-90°C. Heat exchangers or cooling systems might be needed to maintain this temperature.

- Pressure: Slightly above atmospheric pressure (typically 1-3 bar) to prevent boiling of the brine solution.

- The electrodes shall be able to withstand the electrolysis temperature.

- The pipe system shall be able to withstand a temperature of up to 100°

- The valves shall be able to resist temperature and pressure.

- The separator shall be able to separate NaOH liquid from H₂ gas and NaCl from Cl₂ gas.

Chemical requirements

- Brine Concentration: 25–32% by weight NaCl

- The electrodes shall be able to withstand the corrosion with NaOH since the pH in the cathode compartment will be high (around 13–14).

- The membrane shall be able to allow the ions to pass through so that electrolysis takes place when the current is connected.

- The membrane shall be able to insulate the two half-cells chemically. 

- The membrane shall be made of Nafion.

- Valves shall be made of polypropylene (PP) or PFA (perfluoroalkoxy) for chlorine gas and brine and nickel alloys or special stainless steel for sodium hydroxide to be compatible with the corrosive environment.

- Pumps are similar to valves, material selection is crucial for compatibility with the pumped liquids (brine, sodium hydroxide). Consider materials like PP, PFA, or metallic options with appropriate corrosion resistance.

- The pipe system used shall be able to withstand corrosion with NaOH and Cl_2.

- The metal separator used shall be able to withstand corrosion with NaOH and Cl₂.

Mechanical requirements

- The electrodes shall be thick enough to withstand the pressing (the pressing of the screw rods).

- The electrodes shall be thick enough to press the gaskets so that no gas can exit.

- The gaskets shall be able to prevent the leakage of gases and liquids from the cells.

- The gaskets shall be made of thermal caoutchouc.

- The pipe connections shall be able to resist the gas pressure without letting gas exit through.

- The pressure of the pump shall be sufficient to fill the cells and not too high for the pipe system.

- The valves shall be able to close completely.

- The valves shall be able to open or close with independent pressure.

- System shall be manufactured following the Freecad Chlor-alkali mechanical design 28/03/2024

Electrical requirements

- For power supply, DC the current that passes through one cell shall be 25-97 A with a needed voltage of 2-4 V

- The power supply shall be able to let the electrolysis generate enough hydrogen so that we can burn it.

- The valves shall be able to be controlled from the GUI.

- The conditions to obtain a minimum value for cell voltage and highest current efficiency shall be as follow: pH=2, T=90C, flow=5.9 cm/s, brine concentration=300 g/L, current density=1 kA/m².

Safety requirements

- The hydrogen burner shall be able to burn the produced hydrogen gas to avoid the risk of its explosion.

- Installment of Flashback arrestors to allow the gas to flow in the intended direction towards the torch but restricts the flame from traveling back up the hoses towards the gas source (tanks or cylinders).