Rapidly Drying Sorghum Biomass for Potential Biofuel Production

Abstract

The Southern U.S. has an ideal climate that may aid in growing large amounts of biomass potentially suitable for biofuel; however, short-term droughts during the growing season may reduce yields. Sorghum may have great potential as an energy crop, because it is capable of high biomass yields and is drought resistant. Sorghum could be integrated into a conservation system as part of a crop rotation. However, sorghum biomass has relatively high moisture content and should be conditioned and dried before transported to reduce costs. Sorghum-sudan hybrid was harvested with two different headers on a self-propelled windrower: a Massey Ferguson 9145 (sickle) and a Massey Ferguson 9185 (disc). The disc header was comprised of two pairs (rear / front) of metal conditioner rollers which compressed the biomass, thus improving the drying process. The roller pairs were used with three different pressures (0, 3500 and 7000 kPa), and with different gaps (0 and 0.02 m). Sorghum biomass samples were collected after harvest and moisture content (%) evaluated daily until they remained constant. Results revealed that the higher pressures and smaller gaps resulted in faster drying of biomass. Thus, the best settings for the disc header were "7000 kPa - 0 m" or "7000 kPa - 0.02 m" which showed, respectively, moisture content levels of 13.6 % and 16.8 % after 14 days. However, when the disc header was set to "0 kPa - 0.02 m", the moisture content was significantly higher (43.2%). These results indicate that proper setting of the disc header including properly setting the pressures and gaps are important to achieve optimum drying of biomass.