Effects of physical properties and operating parameters on soybean flaking

Abstract

AbstractThe soybean crushing industry aims at attaining greater oil extraction by optimizing flake thickness. This involves modifying the physical and viscoelastic properties of cracked soybeans and adjusting operational settings of the flaking roll stands. Vibratory feeders distributed 20–32% fewer cracked soybeans at the roll ends and 12% fewer cracks at the center. This increased the variability in roll wear and flake thickness along the length of the rolls. The flow rate distribution produced by rotary feeders was more uniform. Vibratory feeders produced a uniform particle size distribution of cracks (diameter range 2.71–2.76 mm) along the length of the rolls. At constant roll pressure, the increased flow rate of cracks increased the flake thickness and power consumption. While roll stands were operating at their rated flow capacity, the desired flake thickness range (0.25–0.38 mm) could not be obtained by merely increasing the roll pressure, because it caused hot spots in the rolls. Modifications of the metallurgical properties of the rolls and the viscoelastic properties of the soybeans are possible means of reducing flake thickness. During six plant visits, 73.2% of the sampled flakes were thicker than the maximum desired value (0.38 mm). This may be costing the U.S. soybean milling industry an annual loss in oil revenues of S7–16 million.