Master of Science in Biological and Agricultural Engineering (MSBAE)


Biological and Agricultural Engineering

Document Type



In the recent years, processing sweet sorghum feedstock to obtain syrup for biofuels production is an option that has gained attention, especially where sugar cane milling infrastructure is already available; however, the leafy matter and panicles (trash) in the feedstock could negatively impact the process. Therefore, it seems sensible to reduce the trash level in the feedstock prior to milling and expand the current knowledge on the effect of trash in the juice and syrup. In this project, a pneumatic system to separate the leaves from sweet sorghum harvested with a sugar cane billet harvester was tested and a panicles separator was developed, since the panicles separation with air has proven before to be ineffective. In addition, the effect of the trash on the fermentable sugars, starch, ash and organic acids in juice was investigated by milling four different treatments of feedstock and four different levels of trash % feedstock. Also a computer simulation of a sugar cane mill and a basic economic analysis was conducted to assess the effect of the trash in the sweet sorghum syrup. The results on the pneumatic separator showed that the highest leaves separation efficiency of 56 ± 3% (no billets lost) is obtained at an air stream angle of 45° in between 0.6 m below the conveyor and with the splitter located at a horizontal distance of 2.06 ± 0.06 m from the conveyor. The panicles separator prototype achieved a selectivity of 9.5 ± 1 at 30° when operated at 43 rpm. Finally, it was demonstrated that by reducing the trash level in the feedstock, there was a decrease in the bagasse and a decrease in the starch and ash in the juice but an increase in the amount of fermentable sugars per tonne of feedstock in the syrup. Also the brix extraction in the milling tandem was improved and the energy consumption to produce syrup was reduced. Furthermore, in terms of revenue, even though the cogeneration decreased as the trash was removed, the overall estimated revenue increased because the gains from the fermentable sugars proved to be greater.



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Committee Chair

Aragon, Daira



Included in

Engineering Commons