A team of scientists led by a WSU researcher has found a way to tune a major industrial chemical process to create commercially important fuels, lubricants and detergents in a simple, one-step process.
Led by Norbert Kruse, Voiland Distinguished Professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, the group has discovered a new way to control and direct the Fischer-Tropsch process, which is used to produce synthetic fuel and oils. The discovery that varying relative amounts of reactants change the catalyst composition and the product portfolio is a breakthrough in the foundational understanding of the reaction.
The researchers, including Yizhi Xiang, a postdoctoral researcher at WSU and Libor Kovarik of Pacific Northwest National Laboratory, have co-authored a paper on the work in the high-impact journal Nature Communications.
The Fischer-Tropsch process uses a catalyst to turn hydrogen and carbon monoxide into mostly diesel and is an alternative to petroleum processing. By varying the ratio of hydrogen and carbon monoxide in the reaction over a wide range, the team was able to change the products of the reaction from diesel fuel to oils containing large amounts of alcohols and aldehydes, which are used to make lubricants, plasticizers and detergents.
“For the first time ever, we are able to regulate and direct this reaction to produce diesel fuel, alcohols or aldehydes,” said Kruse. “This discovery opens up new avenues to tune the catalytic performance of the reaction ultimately leading to high product selectivity and avoiding undesired waste formation.”
At low hydrogen to carbon monoxide ratios, the team found that the cobalt used as a catalyst changes its composition, becoming cobalt carbide. The formation of cobalt carbide changes the selectivity of the reaction, causing the production of mostly alcohols and aldehydes. At higher ratios, diesel is mostly produced instead. All these products contain long-chain hydrocarbon skeletons.
“We can jump back and forth in creating these products. One could even think to bring this reaction into a self-oscillatory state,” said Kruse. “Our process provides a simple way to direct the production of these valuable hydrocarbons, saving time and reducing overhead. We have known about the Fischer Tropsch process for nearly a hundred years, but we did not really understand many important aspects of it.”
The reactants, carbon monoxide and hydrogen, could also be produced from biomass, like sawdust, shavings, bark and other forestry residues, so an environmentally friendly, overall green process could be designed.