Dr. John Uhlrich, Editor-in-Chief of Energy Technology, talks to Professor George W. Huber, University of Wisconsin–Madison, USA, about his recent article on the production of sustainable liquid transportation fuels from lignocellulosic biomass. The work details the hydrodeoxygenation (HDO) of pyrolysis oils and the relative yields of the different types of product fuel produced.
Could you briefly explain the focus and findings of your article?
Hydrotreating of pyrolysis oils is a technology to produce renewable gasoline, jet, and diesel fuel from wood. Previously, there have been questions about the chemistry that is involved in this process. In our article, we have more clearly analyzed the products and described the reaction chemistry that occurs in hydrotreating. We also show some of the challenges and suggest ways in which they might be overcome.
Could you please explain the motivation behind the study?
The motivation is to develop economical technologies that can produce low-carbon liquid transportation fuels from biomass. These technologies will improve the environment and help improve rural economies. The challenge is that they are not economical yet because less than 40 % of the energy in the biomass is converted into liquid transportation fuels.
How long did this investigation take?
It took around six months to set up the experimental equipment for these experiments and around twelve months to collect all the data and analyze it.
What is the role of such fundamental chemical engineering process development for the next-generation biorefinery?
Chemical engineering is central to all aspects of developing the next-generation biorefinery. Chemical engineers need to understand the chemistry, the catalysis, the analytical challenges, the different unit operations, how to control the technology, the economics of the technology, and how to scale it up. Chemical engineering is all about creating value out of lower value products by refining them. The most surprising finding to me was how many cyclic alkanes were generated in this process. In hindsight, they all come from the lignin.
What are some of the most important research areas for realizing a biomass-to-fuels process?
The most important future development in this area is to demonstrate highly carbon-efficient technologies at larger scale. A lot of things have been demonstrated in the lab, but until they are demonstrated in continuous studies at the pilot plant scale, they will not be practiced commercially. There are major issues with catalyst stability and improving the overall yield. There are also lots of challenges with solids handling. Academics have a lot more freedom to talk about the critical challenges and problems with such technologies than industry or even national labs. Academic research really is critical to developing these technologies.
How will you follow up on this work?
We have continued work on this technology and on identifying the chemistry that lignin undergoes during pyrolysis and hydrotreating. We have also developed non-precious metal catalysts that are stable under these conditions.
The article they talked about
- Hydrodeoxygenation of Pyrolysis Oils,
Kamalakanta Routray, Kevin J. Barnett, George W. Huber,
Energy Technol. 2017, 5, 80–93.
Also of Interest
- Special Issue: Pyrolysis for Energy Technologies,
Energy Technol. 2017, 5 (1).
Contributions on catalysis, biomass chemistry, and process engineering; Guest Editors George W. Huber and Robert Brown