University of Massachusetts Amherst chemical engineers have developed a way to produce high-volume chemical feedstocks including benzene, toluene, xylenes, and olefins from pyrolytic bio-oils - the cheapest liquid fuels available today derived from biomass.
Instead of buying petroleum by the barrel, chemical manufacturers will be able to use relatively cheaper, widely available pyrolysis oils made from waste wood, agricultural waste, and non-food energy crops to produce the same high-value materials for making everything from solvents and detergents to plastics and fibers.
As chemical engineer George Huber, the Armstrong Associate Professor at UMass Amherst, explains, "We can meet the need to make commodity chemical feedstocks entirely through processing pyrolysis oils. We are making the same molecules from biomass that are currently being produced from petroleum, with no infrastructure changes required."
He adds, "We think this technology will provide a big boost to the economy because pyrolysis oils are commercially available now. The major difference between our approach and the current method is the feedstock; our process uses a renewable feedstock, that is, plant biomass. Rather than purchasing petroleum to make these chemicals, we use pyrolysis oils made from non-food agricultural crops and woody biomass grown domestically. This will also provide United States farmers and landowners a large additional revenue stream."
In the past, these compounds were made in a low-yield process, Huber adds. "But here we show how to achieve three times higher yields of chemicals from pyrolysis oil than ever achieved before. We’ve essentially provided a roadmap for converting low-value pyrolysis oils into products with a higher value than transportation fuels."
Huber and doctoral students Tushar Vispute, Aimaro Sanno, and Huiyan Zhang made olefins such as ethylene and propylene, the building blocks of many plastics and resins, plus aromatics such as benzene, toluene, and xylenes found in dyes, plastics, and polyurethane, from biomass-based pyrolysis oils. They used a two-step, integrated catalytic approach starting with a "tunable," variable-reaction hydrogenation stage followed by a second, zeolite catalytic step. The zeolite catalyst has the proper pore structure and active sites to convert biomass-based molecules into aromatic hydrocarbons and olefins.
The team's findings indicate that the olefin-to-aromatic ratio and the types of olefins and aromatics produced can be adjusted according to market demand. Using the new techniques, chemical producers can manage the carbon content from biomass they need, as well as hydrogen amounts.
A pilot plant on the UMass Amherst campus is now producing these chemicals on a liter-quantity scale using the new method. The technology has been licensed to Anellotech Corp., co-founded by Huber and David Sudolsky.
Sudolsky, Anellotech’s CEO, says, "There are several companies developing technology to produce pyrolysis oil from biomass. The problem has been that pyrolysis oils must be upgraded to be useable. But with the new UMass Amherst process, Anellotech can now convert these pyrolysis oils into valuable chemicals at higher efficiency and with very attractive economics. "