Ethanol Production from Corn Fiber Separated after Liquefaction in the Dry Grind Process

Conversion of corn fiber to ethanol in the dry grind process can increase ethanol yields, improve coproduct quality and contribute to process sustainability. This work investigates the use of two physio-chemical pretreatments on corn fiber and effect of cellulase enzyme dosage to improve ethanol yields. Fiber separated after liquefaction of corn was pretreated using (I) hot water pretreatment (160 °C for 5, 10 or 20 min) and (II) wet disk milling and converted to ethanol. The conversion efficiencies of hot water pretreated fiber were higher than untreated fiber, with highest increase in conversion (10.4%) achieved for 5 min residence time at 160 °C. Disk milling was not effective in increasing conversion compared to other treatments. Hydrolysis and fermentation of untreated fiber with excess cellulase enzymes resulted in 33.3% higher conversion compared to untreated fiber

Fouling Rates of Synthetic Thin Stillage

Proteins, carbohydrates, fats, ash and fiber in corn thin stillage are involved in evaporator fouling. It is not understood which components increase fouling rates. Costs associated with fouling include labor and equipment needed to clean fouled heat transfer surfaces, increased capital, antifoulant chemicals and production losses. Effects of starch (STA) and glucose (GLU) composition in a synthetic thin stillage fluid on fouling resistance (Rf) were studied. Effects of total solids (TS) content (1 to 10% db) on Rf (m2K/kW) was investigated. Synthetic thin stillage viscosity was measured using a Rapid Visco Analyzer to determine the synthetic thin stillage Reynolds Number (NRe). Fluid flow was turbulent (NRe > 4000) for synthetic thin stillage with 1% TS and was constant, irrespective of STA:GLU ratio. NRe for synthetic thin stillage with 5 and 10% TS and having various starch:glucose (STA:GLU) ratios was laminar (NRe < 2100) and ranged from 500 to 1100. An annular probe was used to measure fouling tendencies of synthetic thin stillage and Rf was found at the end of 10 hr or until the probe temperature reached 170°C. Treatments with 1% TS, 10 hr long and STA:GLU composition varying from 1:9 to 9:1 ratio had Rf range of 0.254 to 0.303 m2K/kW. Synthetic thin stillage with STA only had Rf range of 0.287 to 0.365 m2K/kW. Synthetic thin stillage with 5% TS and GLU only did not foul after 10 hr while 5% TS and STA only reached the maximum probe temperature, 170°C in 4.2 hr and had Rf = 0.264 m2K/kW. Synthetic thin stillage with 10% TS and STA:GLU of 1:9 had Rf = 0.163 m2K/kW at the end of 10 hr but did not reach the maximum probe temperature, 170°C. As STA:GLU increased to 3:7, maximum probe temperature was reached in 4.2 hr with final Rf = 0.264 m2K/kW. Therefore, for 1, 5 and 10% TS, Rf increased mainly because of the starch present in synthetic thin stillage, while glucose had a smaller effect on Rf. Higher concentrations of starch in synthetic thin stillage had shortened the time to reach the maximum probe temperature.published or submitted for publicationnot peer reviewedU of I OnlyUnpublished dat

Design of an aerosol mass spectral interface

Issued as final reportThis item was temporarily removed from SMARTech at the request of the Georgia Tech Research Institute on May 8, 2009