Advanced BioFuels USA

(National Renewable Energy Laboratory) National laboratory researchers demonstrate improvements in bio-oil yield through catalyst and process development.  —  Researchers from the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Argonne National Laboratory (ANL) have identified an approach to improve the efficiency and reduce costs of biofuel production that moves beyond conventional strategies.

A culmination of years of catalyst development research, “Driving towards cost-competitive biofuels through catalytic fast pyrolysis by rethinking catalyst selection and reactor configuration,” was published in Energy and Environmental Science and details the catalytic fast pyrolysis (CFP) process in which researchers modified catalyst composition and reactor configuration to boost bio-oil yields.

Leveraging the Advantages of the CFP Route to Biofuels and Bioproducts

One benefit of CFP is its compatibility with a wide variety of lignocellulosic biomass. This feedstock flexibility, coupled with a diverse set of potential products, provides the foundation for a robust biorefinery concept. However, existing CFP processes use zeolite catalysts in riser reactors and suffer from lower than desired bio-oil yields. Recently, researchers from three national labs developed an alternative CFP approach that uses bifunctional catalysts in a fixed-bed reactor configuration and operates at atmospheric pressure. The modifications in catalyst type and reactor configuration have made all the difference in terms of increased bio-oil yields and lower costs.

“Zeolites form a lot of coke. As result they are used in a riser reactor system equipped with inline catalyst regeneration,” said NREL Senior Process Research Scientist Calvin Mukarakate, a co-author of the study. “In our case, we targeted a catalyst that doesn’t form a lot of coke and can achieve long reaction time on stream in a fixed bed reactor system. We noticed that, in addition to increased reaction times, we saw a significant increase in the yields of upgraded bio-oil compared to standard methods.”

New Approach Improves Overall Economics and Environmental Impact

A first-of-its-kind technical and economic evaluation of this alternative approach revealed a 50% relative improvement in overall carbon efficiency to fuel blendstocks, as compared to conventional CFP strategies.

“The techno-economic analysis included in the report provides a unique perspective,” said NREL’s Mike Griffin, a chemical engineer and lead author. “The calculations showed that our approach was cost-advantaged compared to conventional CFP processes. That’s really interesting because the catalyst—platinum on titanium dioxide—uses an expensive noble metal. However, the extended lifetime of the catalyst and the improved carbon yields of the process translated to an overall reduction in the fuel blendstock production cost.”

The environmental benefits of the process are also worth noting. Results of a life cycle analysis showed that total supply chain greenhouse gas emissions for the fuel blendstock is approximately 80% lower compared to conventional gasoline. READ MORE