Direct conversion of calcium carbonate to C1–C3 hydrocarbons

Abstract

With the objective of investigating the direct conversion of inorganic carbonates such as CaCO₃ to hydrocarbons, assisted by transition metal ions, we have carried out studies on CaCO₃ in an intimate admixture with iron oxides (FeCaCO) with a wide range of Fe/Ca mole ratios (x), prepared by co-precipitation. The hydrogen reduction of FeCaCO at 673 K gives up to 23% yield of the hydrocarbons CH₄, C₂H₄, C₂H₆ and C₃H₈, leaving solid iron residues in the form of iron metal, oxides and carbide particles. The yield of hydrocarbons increases with x and the conversion of hydrocarbons occurs through the formation of CO. While the total yield of hydrocarbons obtained by us is comparable to that in the Fischer–Tropsch synthesis, the selectivity for C₂–C₃ hydrocarbons reported here is noteworthy.