The Potential for Biomass Production and Conversion in Iowa

Grant # 93-13-02
Principal Investigator: Robert C. Brown
Organization: Iowa State University
Graduate Students: Nate Brown, Colin Brue,
Ming Xu
Undergraduate Students: Matt Borden
Staff Support: Jerod Smeenk, Glenn Norton,
Andy Suby
Technical Area: Renewable Energy

Background and Significance

Thermal gasification is the conversion of biomass into flammable gas mixtures, sometimes known as producer gas, consisting of carbon monoxide (CO), hydrogen, methane (CH4), nitrogen (N2), carbon dioxide (CO2), and smaller quantities of higher hydrocarbons. This gas can be burned directly in a furnace to generate process heat or it can fuel internal combustion engines, gas turbines or fuel cells. The gas can also serve as feedstock for production of liquid fuels. Because of this flexibility of application, gasification has been proposed as the basis for “biorefineries” that would provide a variety of energy and chemical products, including electricity and transportation fuels.

Gasification consists of two processes acting in parallel: combustion and pyrolysis. Combustion is the rapid oxidation of fuel accompanied by the release of large quantities of heat (that is, a fast, exothermic reaction). Pyrolysis is the thermal degradation of solid fuel into a variety of simple gases and organic vapors and liquids. Pyrolysis is an endothermic process, requiring an external source of heat for the reaction to progress. Combustion is encouraged by the addition of air or oxygen to the gasifier only to the extent that heat is required to drive pyrolysis.

Objectives

The objective of this project is to develop a biomass gasifier at the pilot plant scale. Work includes evaluating new gasification technologies, developing hot gas cleanup systems and quantifying gas quality. Some specific activities include production of hydrogen from switchgrass and conversion of syngas to biodegradable polymers.