Making Hydrogen Gas from Sulfur Dioxide and Water at Low Temperatures

This patent describes a method for producing hydrogen gas using an electrochemical cell that reacts gaseous sulfur dioxide and water at a relatively low temperature, generating protons that become hydrogen.

What it covers

This patent details a process for making hydrogen gas using an electrochemical cell. The cell has an anode, a cathode, and a membrane separating them. A voltage is applied across the anode and cathode. Gaseous sulfur dioxide (SO2) is fed to the anode, and water (H2O) is fed to the cathode. A portion of the water travels through the membrane to the anode. At the anode, the SO2 reacts with the H2O in the gas phase, with the H2O being the limiting reactant, to produce sulfuric acid (H2SO4) and hydrogen protons (H+). These protons then pass through the membrane to the cathode, where they are reduced to form hydrogen gas. For instance, this process could be used to convert sulfur dioxide, a common industrial emission, into valuable hydrogen fuel.

What it doesn't cover

• —Does not cover hydrogen production methods that do not use an electrochemical cell with a membrane separating the anode and cathode.
• —Does not cover processes where gaseous sulfur dioxide (SO2) is not fed to the anode as a reactant.
• —Does not cover hydrogen production where water (H2O) is not the limiting reactant in the anode reaction.
• —Does not cover methods where the specific reaction SO2 + 2H2O → H2SO4 + 2H+ + 2e− does not occur at the anode.
• —Does not cover high-temperature hydrogen production, as the claims specify operation at 80° Celsius or below.

The clever bit

The novelty lies in the specific electrochemical reaction at the anode, where gaseous sulfur dioxide reacts with water (which is the limiting reactant) to efficiently produce protons for hydrogen generation, all while operating at a comparatively low temperature.

Why it matters

Hydrogen is a clean energy carrier, and finding efficient, low-cost ways to produce it is crucial for a sustainable future. This patent focuses on a method that operates at a relatively low temperature (around 80° Celsius, as per claim 3), which could reduce the energy input and cost compared to high-temperature electrolysis methods. This could make hydrogen production more economically viable for various industrial and energy applications.

Real-world examples

• 1.Industrial hydrogen production
• 2.Fuel cell applications
• 3.Chemical manufacturing processes requiring hydrogen
• 4.Energy storage systems