The Engineer

Biomass gasification process doubles fuel production

News

A new method of converting feedstock into fuel not only reduces greenhouse gas emissions but also doubles the amount of fuel that can be made from an acre of biomass.

The gasification process was developed by researchers at the University of Massachusetts (UMass) Amherst and Minnesota University.

Paul Dauenhauer of the UMass Amherst chemical engineering department said that the new approach involves the gasifications of biomass in the presence of precisely controlled amounts of carbon dioxide and methane in a special catalytic reactor.

He said that applying the new technique allows the researchers to use 100 per cent of the carbon in the biomass for making biofuels. That doubles the proportion of fuel-producing carbon produced by a conventional gasification process done in one reactor while converting biomass to biofuels.

Dauenhauer claims that the new method, when perfected in as little as two years, could be a major step forward in the quest for a production-ready process to convert biomass to biofuel.

Currently, biomass can be converted to fuels by gasification, which uses high temperatures to break feedstock down into carbon monoxide and hydrogen, which can then be made into various fuels, including hydrocarbons. However, there is 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. The question for Dauenhauer and the research team was how to improve that technology. One of the ways is to control the breakdown environment.

To increase the yields from gasification, the researchers added carbon dioxide, which promotes a well-known reaction: the carbon dioxide combines with hydrogen to produce water and carbon monoxide. However, adding carbon dioxide isn’t enough to convert all of the carbon in biomass into carbon monoxide instead of carbon dioxide. It is also necessary to add hydrogen, which helps, in part, by providing the energy needed to drive the reactions.

The new gasification process uses methane, the main component of natural gas, to generate the hydrogen within the reactor. While it has been possible previously to perform 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, which is the key to making the process affordable, according to Dauenhaer.

A commercial version of the process could be set up near an existing natural gas power plant, which would provide ready access to methane and carbon dioxide.