Variation with time of cell voltage for coal slurry electrolysis in sulfuric acid

• Cell voltage improves with decreasing coal rank (lignite < anthracite).
• Addition of Fe2+ improves cell voltage compared with that of Fe3+.
• Electrolytic cell voltage reduces in the order Co2+ < Ni2+ < Fe2+.
• Cell voltage reduces with increasing coal water slurry concentration.

To explain the time dependence of cell voltage in CWS (coal water slurry) electrolysis, the effects of three coal types along with graphite, CWS concentration and catalysts on cell voltage are examined. Results show that the overall cell voltage for CWS electrolysis is lowered as coal rank decreases. The four overall types carbonaceous material show successive reductions in Uθ + η for CWS electrolysis which are greater than those of iR, where Uθ is the theoretical reversible potential for water electrolysis, and η is the sum of the anodic and cathodic over-potentials. The cell voltage for DLWS(demineralized lignite water slurry ) electrolysis is lowered by addition of Fe2+ or Fe3+ ions, the former being more effective. The cell voltage for DBWS (demineralized bituminous water slurry) electrolysis decreases with the addition of transition metal ions in the order Fe2+