Sugarcane or sweet sorghum processing techniques for production of alcohol by fermentation

Abstract

Experimental and theoretical studies of processing techniques for production of alcohol from sugarcane or sweet sorghum were conducted. Stalk chopping, juice extraction, and pulp extraction were the feedstock processing areas evaluated. These areas were evaluated in laboratory conditions from the following viewpoints: (1) yield of ethanol and production efficiency, (2) theoretical production process energy, (3) production process volume and water requirements and, (4) materials handling. The effect of each feedstock processing option was determined. The results of the tests demonstrated that chopping stalks 1 cm (0.39 in) long and subsequent fermentation will produce a high yield of alcohol but required the most energy, the most process volume, the most process water and presented materials handling problems. Results indicated that juice extraction and fermentation resulted in a loss of alcohol production but was the most feasible from an energy and production viewpoint. The highest yield of alcohol was 79.9 L/t (19.1 gal/ton) for sugarcane and 74.0 L/t (17.8 gal/ton) for sweet sorghum with stalks chopped into 1 cm (0.39 in) lengths. Juice extracted with a roller mill produced 47.7 L/t (11.5 gal/ton) for sugarcane and 43.7 L/t (10.5 gal/ton) for sweet sorghum. Extracted juice required the least amount of theoretical energy for cooking and distillation for sugarcane and sweet sorghum. The juice required no process water and was very favorable from a materials handling viewpoint.