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Title:Technical and economic viability of value added product recovery in the corn dry grind ethanol process
Author(s):Kurambhatti, Chinmay
Director of Research:Singh, Vijay
Doctoral Committee Chair(s):Singh, Vijay
Doctoral Committee Member(s):Rausch, Kent D; Tumbleson, Mike E; Jin, Yong-Su; Kumar, Deepak
Department / Program:Engineering Administration
Discipline:Agricultural & Biological Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Corn dry grind
Purple corn
Abstract:Although ethanol is the primary product of the corn dry grind ethanol process, other coproducts in the dry grind process also contribute to sustainability. However, low coproduct value is responsible for high dependence of plant profitability on ethanol revenue. Improving coproduct value and recovering high value coproducts would improve economic performance of the dry grind process and reduce dependence on revenue from ethanol. Developments in process engineering, breeding and genetic engineering have enabled process modifications for improving coproduct value and recovering value added products in the dry grind ethanol process. Use of corn fractionation techniques in the dry grind process increase the number of coproducts, enhance their value, generate an inexpensive feedstock for cellulosic ethanol production and potentially increase profitability of the corn dry grind process. The aim of this study was to develop process simulation models in SuperPro Designer and evaluate commercial scale technoeconomic feasibility of eight wet and dry corn fractionation techniques recovering germ, pericarp fiber and/or endosperm fiber. Ethanol yields for dry grind plants processing 1113 MT corn/day were 37.2 to 40.0 million gal/yr for wet fractionation and 31.3 to 37.3 million gal/yr for dry fractionation, compared to 40.2 million gal/yr for a conventional process. Capital costs were higher for wet fractionation processes ($92.9 to 97.4 million) in comparison to conventional ($83.95 million) and dry fractionation ($83.4 to 84.9 million) processes. Due to higher values of coproduct, ethanol production costs in plants with fractionation technologies ($1.29 to 1.59/gal) were lower than conventional ($1.36/gal) process. Internal rate of return for wet (8.6 to 4.1%) and dry fractionation (6.5 to 7.0%) processes were higher than the conventional (6.4%) process. The wet fractionation process designed for germ and pericarp fiber recovery was most profitable among processes studied. Water based anthocyanin recovery provides a ‘natural’ anthocyanin extract with diverse applications in the food industry. The objectives of our study were to improve water based anthocyanin recovery from purple corn and to assess technoeconomic feasibility of integrating improved anthocyanin recovery processes and ethanol production at a commercial scale. Anthocyanin recoveries of 48.6, 68.6, 77.9 and 66.8% with single stage, two stage, three stage sequential and two stage countercurrent water based extractions, respectively, from corn pericarp were higher than recoveries (30.8%) with previously optimized process conditions. Annual ethanol and anthocyanin yields for plants processing 1113 MT purple corn/day were between 35.2 and 36.3 million gal/yr and 496 and 795 MT/yr, respectively for processes modified for water based anthocyanin extraction, compared to 42.0 million gal for conventional dry grind process. Capital costs for modified processes ($97.4 to 101.4 million) were higher than conventional process ($87.2 million). Due to high value of anthocyanins, ethanol production costs for modified processes ($0.48 to 0.98/gal) were lower than the conventional process ($1.34/gal). Internal rate of return for modified technologies (17.2 to 27.4%) were 1.9 to 3.1 times that of conventional processes (8.9%). Anthocyanin extraction process with three stage anthocyanin recovery had highest internal rate of return among the processes. 2’-fucosyllactose (2’-FL) is one of the most abundant human milk oligosaccharides and has been linked with reduced risks of fatality and intestinal dysfunction in infant piglets. However, high costs associated with synthesis and purification restrict its commercial production. Distillers dried grains with solubles (DDGS) is a post-fermentation coproduct of corn dry grind ethanol process that is extensively used in swine diet formulations. Genetically engineered Saccharomyces cerevisiae strains are capable of producing 2’-fucosyllactose using glucose and lactose as substrates. Enriching DDGS in 2’-fucosyllactose by using these genetically engineered strains for fermentation in dry grind ethanol process would be a cost-effective option to supplement swine diets with 2’-fucosyllactose. The objectives of our study were to optimize dry grind ethanol process using genetically engineered Saccharomyces cerevisiae strain in terms of ethanol and 2’-fucosyllactose yields and evaluate technoeconomic feasibility of the process for commercial scale application. Concentrations of 19.8 g 2’-FL/kg dry DDGS was achieved using staged glucoamylase and whey addition and 25% w/w solid loading in the modified dry grind ethanol process. Ethanol yields in the modified process were less than 10% lower than conventional dry grind process. Capital costs for modified dry grind ethanol processes using whey and whey powder were 48.5% and 38.4% higher than conventional dry grind process, respectively. Use of lower solid loading and whey addition were responsible for the increased capital costs in modified processes. Ethanol production costs and IRR for modified processes were dependent the selling price of 2’-FL enriched DDGS. For DDGS selling prices similar to or more than $300/MT, IRR of the modified processes was higher than conventional dry grind ethanol process.
Issue Date:2021-07-09
Rights Information:Copyright 2021 Chinmay Kurambhatti
Date Available in IDEALS:2022-01-12
Date Deposited:2021-08

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