Title: Saccharification of sugarcane bagasse for ethanol production using the Organosolv process
Abstract: The scope of this work is the reduction of the production cost of fuel ethanol, through hydrolysis of surplus bagasse from sugar mills with annexed distilleries. Ethanol could be obtained from the sugar liquor after fermentation and distillation. An Organosolv process using an ethanol-water mixture as solvent and diluted sulfuric acid (0.1-0.25%) as the reaction catalyst was developed. Reaction was done at 170-185°C and 20-25 kg/cm 2 . The work was done on a bench scale unit (20 kg/h of raw bagasse). Processing for conversion to hexose and pentose sugars was in a short residence time reactor. Reaction products were totally dissolved in the organosolv solvent. Solvent was removed and sugar liquor recovered after removal of precipitated lignin. Results obtained in the pilot plant were: global conversion of bagasse in total reducing sugars was 59%, being sugar content in liquor 80 g/L, after 10-12 minutes of residence time. The final liquor containing reducing sugars was fermented successfully to ethanol after blending with cane juice and molasses. Fermentation used a yeast strain adapted to ferment the hexose fraction despite the high concentration of inhibitors present, such as short chain organic acid, furfural and hydroximetilfurfural. The ratio of hydrolysis liquor to cane sugar components was adjusted to match a maximum level of inhibitor in must. Results of the bench unit were scaled up to a 5000 litres/day pilot and demonstration unit (PDU). Our preliminary feasibility calculations allow us to forecast that the ethanol produced by the organosolv process should be competitive with current ethanol produced directly from cane juice and molasses. There is also a large potential for cost reduction once the hydrolysis reaction is optimised. Development of fermentation of the pentose sugar fraction to ethanol, to be done in the future, will improve the economy of this process. The organosolv technology for bagasse hydrolysis is of medium complexity and Brazil or other developing countries can rapidly have access to it. This process could increase the production of alcohol in Brazil, using the same cane planted area and reducing the production costs, besides allowing the use of many other lignocellulose residues from agriculture, forest industry and others for ethanol production.
Publication Year: 2005
Publication Date: 2005-01-01
Language: en
Type: article
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Cited By Count: 19
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