|CHALLA, RAVI - University Of Illinois
|SINGH, VIJAY - University Of Illinois
|TUMBLESON, MIKE - University Of Illinois
|RAUSCH, KENT - University Of Illinois
Submitted to: Journal of Food and Bioproducts Processing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2014
Publication Date: 10/7/2014
Citation: Challa, R., Johnston, D., Singh, V., Tumbleson, M., Rausch, K. 2014. Fouling characteristics of model carbohydrate mixtures and their interaction effects. Journal of Food and Bioproducts Processing. 93:197-204.
Interpretive Summary: Evaporators used for water removal in fuel ethanol plants develop deposits on the heating surface that cause fouling and significantly reduce energy efficiency and performance. The composition of the material being evaporated is known to influence the rate and degree of fouling. To better understand how we may decrease the fouling problem, we tested solutions with known amounts of material in a model evaporator system. We found that the amount of residual starch present in the model solution as well as the type of starch significantly influenced the rate and the degree of fouling. This information will be of direct benefit to fuel ethanol producers who can use the information to improve operations. US taxpayers will indirectly benefit through relative reductions in fuel cost.
Technical Abstract: Fouling resistances of carbohydrate mixtures were measured using an annular probe at bulk fluid temperatures of 75°C and initial probe surface temperature of 120°C. Induction period, maximum fouling resistance and mean fouling rates were determined. Two experiments were performed with two varieties of starch, waxy and high amylose and short chain carbohydrates, corn syrup solids (CSS) and glucose (GLU). Interaction effects of GLU with starch varieties were studied. In the first experiment, short chain carbohydrates individual and interaction effects with starch (STA) was studied. GLU and CSS showed no fouling, whereas starch (STA), a long glucose polymer, showed marked fouling. CSS and GLU mixed with pure starch decreased the mean fouling rates and maximum fouling resistances. Between CSS and GLU, STA fouling rates were reduced with addition of GLU. Induction periods of pure mixtures of either GLU or CSS were longer than the test period (5 h). Pure starch mixture had no induction period. Maximum fouling resistance was higher for mixtures with higher concentration of longer polymers. Waxy starch had a longer induction period than high amylose starch. Maximum fouling resistance was higher for waxy than high amylose starch. Addition of GLU to waxy or high amylose starch increased induction period of mixtures longer than 5 h test period.