Conversion of biomass products to energy sources in the presence of nanocatalysts and membrane-catalyst systems

Abstract

A particular role in the harmonious exploitation of raw materials is assigned to organic sources of fuels based on renewable biomass. The most promising feedstocks of major energy sources, such as hydrogen and organic components of motor fuels, include ethanol and other bioalcohols, i.e., the primary products of its conversion. In this work, we describe the results for new reactions of conversion of ethanol and a mixture of ethanol and glycerol, which are the major products of biomass, to the C3–C10 alkane-olefin fraction in the presence of nanoscale mono- and bimetal-containing active components supported on γ-Al2O3 (〈d〉 = 5–8 nm) and on the inner surface of microchannels of ceramic membranes (〈d〉 = 15–20 nm). Mono- and bimetallic alkoxide and acetate complexes are used as precursors. It is found that the selectivity for the ethanol conversion to aliphatic hydrocarbons, as well as the content of branched structures, heavily depends on the nuclearity and composition of metal-complex precursors supported on γ-Al2O3. It is found for the first time that glycerol exhibits high reactionary ability in the reaction of cross-condensation of the carbon skeleton of alcohols of different nature. In the presence of a Ta-Re-containing system, a mixture of ethanol and glycerol is converted to 60% of C4–C10+ olefins, which contain up to 50% of branched structures. It is shown that by varying the composition of Pd-Zn-containing active components, it is possible to targetedly convert ethanol to the olefin, alkane, or alkane-olefin fraction. Porous membrane-catalyst systems are designed to produce hydrogen and syngas from biomass products; the systems exhibit high activity in the carbon dioxide and steam reforming of ethanol, a mixture of ethanol and glycerol, and acetic acid. A scheme for the production of a wide range of valuable organic products based on bioalcohols containing no toxic impurities and independent of crude oil is described. According to this scheme, alkanes derived from ethanol and other bioalcohols are the major components of motor fuels; a large number of organic synthesis products can be derived from olefins, hydrogen, and carbon monoxide in the carbonylation/hydrocarbonylation processes.