Conversion of Existing Dry-Mill Ethanol Operations to Biorefineries

Basic corn - to - ethanol manufacturing processes have provided important first steps for biorefining operations but have barely scratched the surface with respect to overall biorefining opportunities. Multiple options exist to modify or supplement existing processes to make these plants more productive and increase the types and quantities of valuable materials that they produce. Some low - value byproducts and wastes generated from these facilities can be converted into higher value products. Additionally, byproducts and wastes from other industries, such as food processing, landscaping, paper, and municipal solid waste facilities, could be substituted for crops as feedstocks and processed into ethanol. This chapter focuses on two incremental modifi cations that dry - mill ethanol plants could implement that would enlarge their feedstock options and also expand the products and associated value of their output. The proposed modifications include (1) incorporation of cellulosic feedstocks into existing operations and (2) recovery of oil for sale as a value - added product. Modification of existing processes to accommodate cellulosic feedstocks could greatly improve the diversity and fl exibility of feedstock options. Recovery of oil from by products such as germ, thin stillage syrup, or dried distillers ’ grains and solubles (DDGS) could expand greatly the quantities and value of products produced from dry - mill plants and also provide valuable feedstock options for biodiesel producers. Multiple other opportunities exist for expanding and diversifying dry - mill ethanol plant feedstocks, processes, and products but are beyond the scope of this chapter. For instance, DDGS could be further fractionated to separate and pelletize high - protein/high - value components from lower value materials. Cogeneration systems could be implemented to burn lignin and other coproducts to simultaneously produce steam and electricity, thereby reducing electricity requirements from external sources and providing electrical power for additional biorefi ning operations. Ethanol is an important industrial ingredient and has widespread use as a base chemical for other organic compounds. These include ethyl halides, ethyl esters, diethyl ether, acetic acid, butadiene, and ethyl amines.