A team of University of Massachusetts Amherst chemical engineers report in Science that they 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. The new process could reduce or eliminate industry's reliance on
fossil fuels to make industrial
chemicals worth an estimated $400 billion annually.
Instead of buying
petroleum by the barrel, chemical manufacturers will now 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 principal investigator George
Huber, associate professor of
chemical engineering at UMass Amherst, explains, "Thanks to this breakthrough, 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, the chemical engineer 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."
In the
paper, he and doctoral students Tushar Vispute, Aimaro Sanno and Huiyan Zhang show how to make
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 use 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.
Huber, Vispute and colleagues discuss how to choose among three options including low- and high-
temperature hydrogenation steps as well as the zeolite conversion for optimal results. Their findings indicate that "the olefin-to-aromatic ratio and the types of olefins and aromatics produced can be adjusted according to market demand." That is, using the new techniques, chemical producers can manage the
carbon content from biomass they need, as well as
hydrogen amounts. Huber and colleagues provide economic calculations for determining the optimal mix of hydrogen and pyrolytic oils, depending on market prices, to yield the highest-grade product at the lowest cost.
A pilot plant on the UMass Amherst campus is now producing these chemicals on a liter-quantity scale using this new method. The technology has been licensed to Anellotech Corp., co-founded by Huber and David Sudolsky of New York City. Anellotech is also developing UMass Amherst technology invented by the Huber research team to convert solid biomass directly into chemicals. Thus, pyrolysis oil represents a second renewable feedstock for Anellotech.