Engineering aspects of collecting corn stover for bioenergy

More than 216 million t (238 million tons) of corn stover (dry basis) is produced annually in the USA of which a portion could possibly be collected for conversion to ethanol and other industrial products. This paper examines published data on collecting corn stover using field machinery, including moisture content, mass fractions, and the amount of stover removed from the field. It is shown that a typical sequence of shredding, windrowing and round baling operations may result in a collection efficiency of < 40%. Other factors such as weather, season, and leaving stover for environmental reasons may also reduce the amount of stover collected per unit area. Collection cost would depend on the amount of stover collected per unit area, the number of operations, machine efficiency in each operation, and bulk density. A typical cost calculated for round baling and delivering the bales to a storage 8 km (5 miles) away from a harvested field amounted to $21.60/dry t ($19.70/dry ton). (C) 2002 Published by Elsevier Science Ltd.