Preparing bioethanol from oat hulls pretreated with a dilute nitric acid: Scaling of the production process on a pilot plant

Abstract

The full cycle of bioethanol production from pretreated oat hulls is scaled for a pilot plant. The one-stage pretreatment of oat hulls with a dilute nitric acid at atmospheric pressure is scaled for a 250-L reactor. The total amount of hydrolysable polysaccharides in the resulting substrate is 87.2%. Using the commercially available enzyme preparations CelloLux-A and BrewZyme BGX and the industrial strain BKPM Y-1693 of Saccharomyces cerevisiae yeast, the process of enzymatic hydrolysis and alcoholic fermentation is successfully scaled for a 63-L reactor. The scaling factor is 1: 400. Bioethanol is obtained with a high yield of 17.9 daL/t. After rectification, the test sample of bioethanol meets the standards for high-purity alcohol from food raw materials according to the mass concentration of aldehydes, esters, and by the content of methanol.