Browsing by Subject "Corn ethanol"

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    Industrial symbiosis: corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion
    (2012-12) Wood, Brandon M.
    The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial co-products. Alternative treatment methods, specifically hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion were investigated to determine if they provide an opportunity to recover some of this value. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65-73% were achieved, while hydrochar, fatty acids, treated process water, and biogas co-products were generated, providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all co-products were again produced, as well as a high quality animal feed. Anaerobic digestion of the undiluted aqueous product stream from thin stillage hydrothermal carbonization reduced chemical oxygen demand (COD) in this product stream by more than 90% and converted 83% the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce natural gas overall usage.
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    Production and purification of phytic acid from distillery wastewater via ion exchange
    (2016-12) Reyes Gaibor, Felipe, S; Rodrigues Reis, Cristiano
    Phytate (inositol hexakisphosphate) is the major form of organic phosphorus present in corn. Phytate is partially degraded during the corn ethanol fermentation process and it still represents over 40% of the phosphorus present in the main co-product generated – distiller’s grains. Phytate has a high market value and its extraction can help decrease phosphorus pollution from distiller’s grains use as animal feed. An ion exchange system has been developed for phytate extraction and purification using the ethanol co-products streams. The feedstock rich in phytate for this study is complex and presents different competing ions for the ion exchange system. The anion exchange resin used is selective for phytate, but is also able to adsorb sulfate, inorganic phosphate, and nitrate – all of which are as concentrated as phytate in the feedstock stream. This study evaluated some of the experimental conditions for better understanding the phytate extraction and purification system, and include the development of multi-component isotherms and multi-anion adsorption kinetics. The adsorption breakthrough for the four anions has also been evaluated on a packed-bed chromatographic column, on a similar design that would be used for larger scale approaches. Desorption from fully loaded resin, followed by a phytate precipitation step, provided salts with purities higher than 90%. This system can, thus, lead to a potential industrial application in order to enhance the profitability of ethanol plants, and simultaneously providing a solution for phosphorus pollution from distiller’s grains use.