Three factors, (i) the ethanol “blend
wall”, which
limits its market as a transportation fuel, (ii) advances in production
efficiency, and (iii) feedstock diversification, could lead to excess
ethanol at competitive prices. Those factors have already motivated
a search for value-added derivatives (e.g., distillate fuels, olefins,
and asymmetric amines). Siting small, low cost, flexible conversion
facilities to process ethanol at or near the fermentation plant could
encourage the growth of an enterprise. Decreasing the barriers to
entry, matching supply and demand, and enhancing access to production
incentives are enabling success factors. This review discusses the
process chemistries that might be employed by such ethanol conversion
facilities based on market prices. Then, we describe how these technologies
might benefit from process intensification to simplify the processing
and to avoid large pressures or large temperature gradients typically
employed in conventional, large scale facilities.