The researchers’ idea is to use heat and oxygen to gasify biomass and produce a medium-Btu synthesis gas that a new catalyst can convert directly into ethanol. They’ll also generate the gas using air to make a low-Btu gas (called producer gas) that can be used in gas-fired heating and drying equipment.

This project partners the thermochemical conversion of biomass with ethanol production. We’re not intending to replace grain ethanol production. We want to complement it.

—Robert C. Brown, the Iowa Farm Bureau Director of Iowa State’s Bioeconomy Institute, an Anson Marston Distinguished Professor in Engineering and the Gary and Donna Hoover Chair in Mechanical Engineering

The burner. Song-Charng Kong, an Iowa State assistant professor of mechanical engineering who is leading development of the new burner (and is overall project leader), said the technology could replace natural gas in conventional ethanol production. That would provide ethanol plants with a clean and renewable source of steam and heat.

Synthesis and producer gases have been used in burners designed for natural gas and other fuels. But Kong said the biomass-based gases aren’t the same kind of fuel.

Biomass, for example, contains fixed nitrogen from the air and from fertilizers used to produce the biomass. Gasifying biomass releases the fixed nitrogen as ammonia in the generated gases. Improperly burning gases containing ammonia could produce nitrogen oxide emissions. Kong’s goal is to develop a burner that will minimize the emission of such pollutants while maximizing combustion efficiency.

A conventional gas burner now at the Iowa Energy Center’s Biomass Energy Conversion Facility in Nevada will provide baseline data to develop computer models of the burner’s performance. Those models will test new designs that optimize the combustion of producer gas from biomass, and lead to the construction and testing of a prototype.

The catalyst. Victor Lin, a professor of chemistry, director of Iowa State’s Center for Catalysis, director of Chemical and Biological Sciences for the US Department of Energy’s Ames Laboratory and founder of Catilin Inc., an Ames-based company that produces catalysts for biodiesel production is leading the development of a new catalyst for ethanol production. Lin says it may be possible to efficiently produce liquid fuel directly from synthesis gas.

The key will be carbon-based nanoparticles just a few billionths of a meter wide. The particles are made from graphite and carry a transition metal that produces a chemical reaction. That reaction converts synthesis gas to ethanol.

Lin said there is an existing chemical catalyst that can convert synthesis gas to ethanol. But that catalyst has a very low yield of ethanol, produces greenhouse gases such as methane, needs heat up to 540 °F (282 ° C) and requires high pressures.

Lin said the new catalyst should work at lower temperatures and pressures while delivering a higher yield of ethanol.

In addition to Brown, Kong and Lin, the research team includes Samuel Jones, an assistant scientist for the Center for Sustainable Environmental Technologies plus seven graduate students and two post-doctoral researchers.

The project also includes two industrial partners: Frontline BioEnergy, an Ames-based company that builds commercial-scale gasification systems; and Hawkeye Energy Holdings, an Ames-based ethanol producer with plants in Iowa Falls, Fairbank, Menlo and Shell Rock.