Biomass can be converted to fuels via a process called gasification, which uses high temperatures to break feedstock down into carbon monoxide and hydrogen, which can then be made into various fuels, including hydrocarbons. But there’s a major drawback–about half of the carbon in the biomass gets converted to carbon dioxide rather than into carbon monoxide, a precursor for fuels. Now researchers in University of Minnesota and the University of Massachusetts, Amherst, have developed a method for gasifying biomass that converts all of the carbon into carbon monoxide.
In the new approach, the researchers gasify biomass in the presence of precisely controlled amounts of carbon dioxide and methane, the main component of natural gas, in a special catalytic reactor that the researchers developed. When they did this, all of the carbon in both the biomass and the methane was converted to carbon monoxide. “In the chemical industry, even a few percent improvement makes a big impact. The increase from 50 percent to 100 percent is profound,” says Dionisios Vlachos, the director of the Catalysis Center for Energy Innovation at the University of Delaware.
To increase the yields from gasification, researchers at the University of Minnesota and UMass Amherst added carbon dioxide, which promotes a well-known reaction: the carbon dioxide combines with hydrogen to produce water and carbon monoxide. But adding carbon dioxide isn’t enough to convert all of the carbon in biomass into carbon monoxide instead of carbon dioxide. It’s also necessary to add hydrogen, which helps in part by providing the energy needed to drive the reactions. It’s long been possible to do each of these steps in separate chemical reactors. The researchers’ innovation was to find a way to combine all of these reactions in a single reactor, the key to making the process affordable.