The world has spent billions to develop ethanol fuel additives, says Mark Snyder, but relatively little to make hydrocarbon fuels directly from biomass, which could potentially provide nearly half of America’s energy.
Snyder, the P.C. Rossin Assistant Professor of chemical engineering, is seeking to convert biomass more efficiently into chemicals and fuels. He collaborates with researchers from six other universities and one national lab in a project funded by a DOE Energy Frontier Research Center (EFRC) at the University of Delaware.
Ethanol additives are derived primarily by fermenting sugars produced from corn. Snyder wants to convert woody residues that are mostly waste products into fuels that are chemically no different from gasoline. Auto engines would not distinguish biomass-derived fuel from regular unleaded, nor would refineries need significant retrofitting. The chemicals produced from biomass could be used in textiles, food packaging, cleaners, plastics, dyes, clothing and cosmetics.
Snyder is developing new, hydrothermally stable titania materials whose pore structure and customized catalytic surface hold promise for liquid-phase biomass catalysis. In this type of catalysis, sugary biomass molecules derived from the breakdown of woody materials are reacted in water at moderate temperatures. The process has advantages over high-temperature gas-phase reactions. It uses less energy, it can process sugar molecules that are unstable at high temperatures, and it can tune solution conditions like pH to control reactions.
Porous titania has been explored for other catalytic applications, but Snyder is the first to use titania to achieve efficient and selective biomass catalysis in the liquid phase. Conventional catalysts used in petroleum and petrochemical refining are unstable under liquid-phase conditions. The challenge in designing new catalysts is to tailor pore size, connectivity and surface function to control how biomass molecules access catalytic sites and how they are transformed into fuels or chemicals.
“The overall biomass-to-liquid-fuels process is essentially carbon-neutral,” says Snyder. “The natural process of photosynthesis during the regrowth of new woody biomass effectively cleans from the atmosphere any CO2 produced during the burning of biomass-derived fuels.”
“Liquid phase biomass conversion has a way to go,” says Snyder. “It’s very promising, but how much it contributes will depend on its level of development.”