From Biomass to Chemicals in One Step

A startup's catalytic process converts biomass directly into components of gasoline.

An early-stage company spun out of the University of Massachusetts, Amherst, plans to commercialize a catalytic process for converting cellulosic biomass into five of the chemicals found in gasoline. These chemicals are also used to make industrial polymers and solvents. Anellotech, which is seeking venture funding, plans to build a pilot plant next year.

Sawdust to gasoline: A process called catalytic pyrolysis converts biomass, such as sawdust, into valuable chemicals. From left to right: sawdust; sludge-like chemicals produced without the catalyst; the powder catalyst; the mixture of aromatic molecules made with the catalyst. Credit: Torren Carlson, UMass

Anellotech's reactors perform a process called "catalytic pyrolysis," which converts three of the structural molecules found in plants--two forms of cellulose and the woody molecule lignin--into fuels. Ground-up biomass is fed into a high-temperature reactor and blended with a catalyst. The heat causes the cellulose, lignin, and other molecules in the biomass to chemically decompose through a process called pyrolysis; a catalyst helps control the chemical reactions, turning cellulose and lignin into a mix of carbon-ring-based molecules: benzene, toluene, and xylenes.

The global market for this group of chemicals is $80 billion a year and growing at a rate of 4 percent a year, says Anellotech CEO David Sudolsky. "We're targeting to compete with oil priced at $60 a barrel, assuming no tax credits or subsidies," he says. The company's founder, George Huber, says his catalytic pyrolysis process can create 50 gallons of the chemicals per metric ton of wood or other biomass, with a yield of 40 percent. The other products of the reaction include coke, used to fuel the reactor.

"The advantage of pyrolysis is that it uses whole biomass," says John Regalbuto, an advisor to the Catalysis and Biocatalysis Program at the National Science Foundation. On average, lignin accounts for 40 percent of the energy stored in whole biomass. But because it can't be converted into sugars the way cellulose can, lignin can't be used as a feedstock for fermentation processes such as those used by some biofuels companies to convert sugarcane into fuels.

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Pyrolysis is also different from gasification, another process for using whole biomass. Gasification results in a mixture of carbon and hydrogen called syngas, which can then be used to make fuel. Pyrolysis, by contrast, turns biomass into liquid fuels in a single step. And while gasification can only be done economically at a very large scale, says Regalbuto, catalytic pyrolysis could be done at smaller refineries distributed near the supply of biomass.

Pyrolysis is an efficient way to use biomass, but it's difficult to control the products of the reaction, and it's difficult to get high yields. The keys to Anellotech's process, says Huber, are a specially tailored catalyst and a reactor that allows good control over reaction conditions. Huber's group at UMass, where he is a professor of chemical engineering, was the first to develop a catalytic process for converting biomass directly into gasoline, and Anellotech's processes are based on this work.