Distributed Physical and Molecular Separations for Selective Harvest of Higher Value Wheat Straw Components Project

Wheat straw (Triticum aestivum L.) is an abundant source of plant fiber. It is regenerated, in large quantities, every year. At present, this potentially valuable resource is greatly under-exploited. Most of the excess straw biomass (i.e., tonnage above that required for agronomic cropping system sustainability) is managed through expensive chopping/tillage operations and/or burnt in the field following harvest, resulting in air pollution and associated health problems. Potential applications for wheat straw investigated within this project include energy and composites manufacture. Other methods of straw utilization that will potentially benefit from the findings of this research project include housing and building, pulp and paper, thermal insulation, fuels, and chemicals. This project focused on components of the feedstock assembly system for supplying a higher value small grains straw residue for (1) gasification/combustion and (2) straw-thermoplastic composites. This project was an integrated effort to solve the technological, infrastructural, and economic challenges associated with using straw residue for these bioenergy and bioproducts applications. The objective of the research is to contribute to the development of a low-capital distributed harvesting and engineered storage system for upgrading wheat straw to more desirable feedstocks for combustion and for straw-plastic composites. We investigated two processes for upgrading wheat straw to a more desirable feedstock: (1) An efficient combine-based threshing system for separating the internodal stems from the leaves, sheaths, nodes, and chaff. (2) An inexpensive biological process using white-rot fungi to improve the composition of the mechanically processed straw stems