Conversion of Inedible Biomass Wastes to Petroleum-related Useful Chemicals Using Iron Oxide Catalysts

摘要

Biomass has been expected to become an alternative resource as useful chemicals for exhaustible petroleum oil. Therefore, many studies have been reported on recovering chemicals from the biomass on the basis of biotechnology including fermentation technique, and so on. There are, however, few reports on biomass-refinery aimed at producing useful chemicals from inedible biomass wastes with the concept of chemical process using solid catalysts, which enables to achieve high productivity and to handle huge amounts. We developed iron-oxide catalysts for producing petroleum-related chemicals from inedible biomass wastes containing water by oxidative cracking. These catalysts composed basically of iron-oxide and zirconia. Lattice oxygen of iron-oxide in the catalysts reacts with biomass-derived organic compounds, yielding ketones and phenols. Consumed lattice oxygen atoms were supplied by active oxygen species generated through decomposition of water over zirconia. The usefulness of the catalysts was examined by the reactions of several inedible biomass wastes, such as palm waste, livestock excreta, fermentation residue, raw glycerin, raw bioethanol and lignin. Biomass wastes were treated under hydrothermal conditions in advance, yielding water solutions containing organic compounds, called black waters. Thus obtained black waters were reacted over the iron oxide catalysts using fixed bed reactors. It was found that ketones, mainly acetone, were produced from palm waste, livestock excreta, fermentation residue and raw bioethanol at high yields. Phenol was obtained from palm waste. In the case of raw glycerin, even if high contents of alkali, allyl-alcohol, propene and acetone were successfully produced. Furthermore, phenols could be recovered from lignin.