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item Dickey, Leland
item Parris, Nicholas

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2004
Publication Date: 3/3/2005
Citation: Dickey, L.C., Parris, N. 2005. Improving particle separation from an ethanol extract to water: settling dependence on fine particle content. Industrial Crops and Products. V.21/3. p.379-385.

Interpretive Summary: Production of ethanol from corn has created a surplus of zein-rich byproducts. Distillers' dried grains and corn gluten, are increasingly difficult to sell but which must be sold to make ethanol plants viable. We have shown that zein extraction and sales can significantly reduce the overall cost of producing ethanol. Sale of extracted zein for non-feed products will enable U.S. corn producers to obtain and maintain higher return from the non-starch component of corn. Zein commercially extracted from corn gluten costs $14 /lb and only a few tons are extracted each year; sales and use of greater amounts are inhibited by its cost. Commercialization of less expensive, larger scale, zein extraction facilities depends on demonstrating a low cost process and demonstration requires capital investment within the financial reach of prospective pioneers. We have previously shown that extracted corn can be separated from the liquid extract with inexpensive equipment. This article explains how the equipment can be operated to obtain useful zein solutions at affordable cost.

Technical Abstract: Separating solid particles from ethanolic corn extracts by gravitational settling into a water layer has been studied as part of a project to develop a low cost method to extract ethanol-soluble protein from corn meal. During settling some of the liquid part of the extract (extract liquid) is entrained by the settling particles. The amount of liquid entrained was determining by measuring the ethanol transferred to the water after settling a batch of extract. When sufficient fine particles were pumped to the settling tank they formed a layer at the extract liquid/water interface. No particle layer formed when the mass fraction of fine particles in the extract was .03 or less. Overall entrainment for the settling was 15% lower than entrainment by centrifuged particles. In-line measurements and recordings of ethanol concentration, density and particle content of the water stream carrying settled coarse particles from the settling tank showed that specific entrainment was greater for finer particles.