Scientists at Pacific Northwest have created the first-ever multi-step catalytic process that converts levulinic acid, a compound derived from waste cellulosic materials, into an alternative fuel component called methyltetrahydrofuran, or MTHF. MTHF would be used with ethanol and pentanes from natural gas liquids as the P-series alternative fuel under a recent DOE proposal. The proposal seeks to meet Energy Policy Act mandates for agencies with a fleet of cars and trucks.
"Our system incorporates multiple chemical reaction steps into one process and creates greater yields than previously available," said Doug C. Elliott, principal investigator and staff scientist with Pacific Northwest's chemical process development group. "It represents a new ability to use levulinic acid in creating environmentally friendly products."
This catalytic process possesses high yield capacity, which means less waste and fewer byproducts. Lab tests indicate an 83 percent yield on a theoretical (molar) basis, equivalent to a yield of nearly 110 gallons of MTHF for every 100 gallons of levulinic acid. On a weight basis, the yield is 63 pounds of MTHF for every 100 pounds of levulinic acid.
DOE has funded the research with about $185,000 over the last two years. An additional $40,000 has been provided by research partners Biofine Inc., of Waltham, Mass., and the New York State Energy Research and Development Authority.
The project is one of several in the alternative feedstock research area that is being pursued through Pacific Northwest's Agriculture and Food Processing Initiative. Pacific Northwest uses levulinic acid produced by Biofine. Levulinic acid is a platform chemical that can be converted into a variety of commercial chemicals, such as solvents and pesticides.
The catalytic process developed by Pacific Northwest is conducted at elevated temperatures and pressures inside a catalytic, continuous flow reactor. Levulinic acid is pumped into a tube, where it is warmed to a range of 40 degrees Celsius then mixed with hydrogen. Both compounds then are mixed together with a catalyst in the reactor. A series of chemical reactions takes place, including multiple hydrogenations (three moles of hydrogen per mole of levulinic acid) and two dehydration reaction steps, to create MTHF.
"Industry has not pursued these conversions of levulinic acid previously because of its high cost," Elliott said.
However, Biofine has created a patented process that produces levulinic acid at low cost by breaking down cellulosic waste, such as paper mill sludge or municipal solid waste. This development makes it affordable for industry to seek new uses of levulinic acid, such as the MTHF application.
Pacific Northwest's project is part of a larger DOE program to create value-added, environmentally friendly products. DOE and the New York State Energy Research and Development Authority have paid Biofine $5 million to construct and operate a full-scale demonstration plant for its new levulinic acid process. DOE's National Renewable Energy Laboratory of Golden, Colo., and Chemical Industry Services Inc. of West Lafayette, Ind., also are working with Biofine on alternative uses of levulinic acid.
Pacific Northwest is one of DOE's nine multiprogram national laboratories and conducts research in the fields of environment, energy, health sciences and national security. Battelle, based in Columbus, Ohio, has operated Pacific Northwest for DOE since 1965.