Co-Production of Hydrogen and Sulfuric Acid by Electrolysis

Hydrogen gas is the cleanest fuel which produces only water as a combustion product with no greenhouse or toxic gases. The combustible hydrogen fuel is an energy carrier but not an energy source. As an element, hydrogen is widely available in nature as a component of water and of hydrocarbons. An energy source is needed to extract the element from these compounds and convert it to the combustible hydrogen gas. Today, the energy source for nearly all hydrogen production is fossil fuel, principally natural gas. The supply of natural gas is limited and its price is increasing. Greenhouse gas and air pollutants are emitted when natural gas is used. Electrolytic extraction of hydrogen from water can overcome these stated problems but is more expensive with the present price of natural gas. Manufacturing the hydrogen with a valuable co-product would address this cost disadvantage. Sulfuric acid is a valuable chemical that is produced in large quantities. This research project helps to develop a procedure for extracting hydrogen from water while producing sulfuric acid as a co-product. An electrochemical cell was designed and developed for the production of hydrogen which uses sulfuric acid as electrolyte. In this electrochemical cell with sulfuric acid as an electrolyte we produce hydrogen at the negative electrode while the positive electrode is bathed in sulfur dioxide which it oxidizes to sulfuric acid. The sulfuric acid is collected at the bottom of the cell as valuable co-product. The presence of SO2 to scavenge the anode substantially reduces the equilibrium voltage required for the direct dissociation of water into hydrogen and oxygen. Various design parameters and the fabrication of the reactor are discussed briefly in the thesis. Experimental results of hydrogen production and current voltage curves are discussed. Sulfuric acid corrosion of cell materials is also discussed