According to Physorg, natural gas is the second largest expense at most ethanol plants behind the cost of the corn. Natural gas is present throughout the production process. It's used in boilers to create steam to liquefy corn starch, distill alcohol and dry leftover distiller grains. Physorg notes an unsourced estimate which states Iowa's total ethanol production accounts for 16 percent of the state's demand for natural gas.
The researchers at Iowa State want to replace the natural gas with producer gas. Producer gas is created by injecting biomass into a fluidized bed gasifier. Inside the gasifier, the biomass reacts with a hot sand-air mixture and creates a blend of hydrogen, carbon monoxide, methane and other flammable gases. The efficient and reliable process releases enough of its own heat for the reaction to be self-sustainable and supposedly produces few emissions. Also, the resulting gas can be easily integrated into a plant's existing boilers.
The primary focus of the study is to design a gasifier large enough to provide energy for an entire ethanol plant.