The purpose of this work was to evaluate the stability of a countercurrent steep system to ensure that variables, including temperature, pump flow rate and steepwater profiles remain stable during long periods of operation. Four runs of alaboratory-scale continuous countercurrent steep system were used to evaluate its thermal and mechanical stability. One run was started with fresh steepwater while the other three were inoculated with light steepwater obtained from a wet-milling plant.Variables, such as steep temperature, steepwater recycle rate and light steepwater draw rate, were monitored. Steepwater characteristics, including pH, SO{sub}2 concentration, lactic acid concentration and steepwater solids content were determined. Six to eight days were required for all of the steepwater variables (pH, SO{sub}2 and lactic acid concentration and steepwater solids content) to reach steady state when light steepwater from a plant was used to inoculate the system. When fresh steepwater wasused, 12 d were needed. The average steep temperature of the 16 tanks during 16 d of continuous operation was 50± 1℃ with a set-point of 50± 2℃. The average pump flow rate for the 8 pumps was 5.0± 0.1 mL/s when the set-point was 5.0 mL/s. The average light steepwater draw rate over nine days was 593 + 49 mL/kg when the setpoint was 600 mL/kg. Corn steeped in this system was wet-milled and product yields were reproducible.
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