Formation of methanol and dimethyl ether from a model gas of blast furnace by-product gas

For the purpose of suppressing greenhouse gases emitted from iron-making systems, the synthesis of methanol and dimethyl ether was studied by using mixture of CO, CO₂ and H₂ gases as a model gas of the blast furnace by-product gas. Since the equilibrium yield of dimethyl ether is estimated to be essentially higher than that of methanol from the blast furnace by-product gases, the objective of this study is to prepare highly active catalysts, based on Cu-ZnO-Al₂O₃, for direct syntheses of dimethyl ether, as well as methanol. Cu-ZnO-Al₂O₃ (Cu/ZnO=4/6, Al₂O₃=14.3% in molar basis) catalyst exhibited the highest activity in the synthesis of dimethyl ether among catalysts tested. From the XPS analysis on the surface of the catalyst, the surface Al₂O₃ content Cu-ZnO-Al₂O₃ (Cu/ZnO=4/6, Al₂O₃=14.3% in molar basis) was remarkably higher than the Cu-ZnO-Al₂O₃ (Cu/ZnO=3/7, Al₂O₃=14.3% in the molar basis). The enhancement of the activity by the increase in Cu content may be attributed to the enrichment of Al₂O₃ species on the surface, Because Al₂O₃ was known to be active in the formation of dimethyl ether from methanol.