|ZHENG, YINGYING - University Of Illinois
|ENGESETH, NICKI - University Of Illinois
|SINGH, VIJAY - University Of Illinois
|TUMBLESON, M - University Of Illinois
|RAUSCH, KENT - University Of Illinois
Submitted to: Food and Bioproducts Processing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2020
Publication Date: 11/21/2020
Citation: Zheng, Y., Johnston, D., Engeseth, N.J., Singh, V., Tumbleson, M.E., Rausch, K.D. 2020. Effects of compositional variables on fouling behavior of thin stillage. Food and Bioproducts Processing. https://doi.org/10.1016/j.fbp.2020.11.009.
Interpretive Summary: Removing water in processing streams for the fuel ethanol process requires the use of significant energy. The fouling of heat exchange surfaces in the evaporators that are used to remove water can significantly increase the energy required. Having a better understanding of the components that can cause fouling or accelerate deposit formation could potentially allow the prevention or minimization and result in energy savings. In order to investigate specific components that might be contributing to fouling of the thin stillage stream from an ethanol plant, an annular probe and compositionally modified thin stillage streams were used. The results showed that sugar alone did not increase the fouling tendency, but insoluble starch did have an impact. Additionally, increasing the suspended solids by adding back solids previously removed from the thin stillage stream also increased fouling. Each of these fouling agents can be minimized with specific processing modifications. This information will be very useful to ethanol processors and others studying the fuel ethanol process.
Technical Abstract: The presence of fouling in evaporators can increase energy consumption as well as capital and labor costs. Limited studies have been conducted on fouling of corn ethanol processing. Process streams are biological in origin and have variable compositions. The objective of this study was to develop an improved understanding of components that accelerate fouling of thin stillage evaporators. An annular fouling probe was used to evaluate compositional variables on fouling behavior of dry grind corn thin stillage. Three experiments were performed with commercial processing streams. In the first experiment, the effects of carbohydrate materials in thin stillage on evaporator fouling were investigated by adding starch and sucrose. In the second experiment, commercial thin stillage samples were treated by adding wet cake. The third experiment was designed to observe if the age of thin stillage sample would affect fouling. The results indicate that fouling resistances increased with starch addition, as well as with wet cake addition, at equal total solids contents. Insoluble starch addition had larger effects than soluble sucrose addition. Sucrose alone did not cause increased rapid fouling.