Prof. Abu-Omar tests a catalytic process to create productive chemical products (Purdue University photo/Mark Simons).
Researchers have discovered a catalytic process that converts biomass into chemical products that are traditionally produced from non-renewable sources. The resultant chemicals are frequent additives for fragrances, flavourings and high-octane fuels.
Researchers at Purdue’s Center for Direct Catalytic Conversion of Biomass into Biofuels (C3Bio) developed the process. The biomass feed contains sustainable and untreated wood chips from poplar, eucalyptus or birch trees.
The process involves a recyclable chemical catalyst, a solvent, pressure and heat. When these are combined the method converts lignin into chemical products over a period of several hours. The resultant liquid stream contains the solvent (which is evaporated and recycled), two phenols and aromatic hydrocarbons used in perfumes and flavourings.
Using another catalytic process, the phenols can be converted into high-octane fuel for cars, jets and race cars. Traditionally, car fuels have an octane rating in the 80s while the fuel produced by the C3Bio team has a rating over 100.
While the catalyst is expensive, the C3Bio team is looking for better ways to recycle it and scale up the system. "A biorefinery that focuses not only on ethanol, but on other products that can be made from the biomass is more efficient and profitable overall," said Mahdi Abu-Omar, Chemical Engineering Professor and team lead. "It is possible that lignin could turn out to be more valuable than cellulose and could subsidize the production of ethanol from sustainable biomass."
The C3Bio Team: Ian Klein (left), Basudeb Saha, Trenton Parsell, and Prof. Abu-Omar (Purdue University photo/Mark Simons).
Traditionally, lignin is considered a biomass waste product. It is a complex molecule that is responsible for the rigidity of plant cell wall structures. Prof. Abu-Omar explains, "We are able to take lignin – which most biorefineries consider waste to be burned for its heat – and turn it into high-value molecules that have applications in fragrance, flavoring and high-octane jet fuels … We can do this while simultaneously producing from the biomass lignin-free cellulose, which is the basis of ethanol and other liquid fuels. We do all of this in a one-step process."
Lignin is typically a hurdle in biomass processes. It will often block the release of sugars or poison enzymes that convert sugars into ethanol. Therefore, many refineries will pre-treat biomass with harsh processes to remove or breakdown the lignin.
Abu-Omar said, "Lignin is far more than just a tough barrier preventing us from getting the good stuff out of biomass, and we need to look at the problem differently … While lignin accounts for approximately 25 percent of the biomass by weight, it accounts for approximately 37 percent of the carbon in biomass. As a carbon source lignin can be very valuable, we just need a way to tap into it without jeopardizing the sugars we need for biofuels."
For more information on the catalytic process, check out the following paper. You can also read about the C3Bio project with On-Step Biofuel production process announced late last year, or check out the video below on Purdue’s green technologies:
Source Purdue.