Pilot plant study on the use of powdered activated carbons to remove various impurities from a sugar refinery liquor

Authors: Lima, Isabel; JIMENEZ, ANA - Carboua International; Eggleston, Gillian; PABON, BENHUR - Carboua International; SARIR, EMMANUEL - Carboua International; THOMPSON, JACK - Lsr Refinery, Llc

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/28/2019
Publication Date: 11/6/2019
Citation: Lima, I., Jimenez, A., Eggleston, G., Pabon, B., Sarir, E., Thompson, J. 2019. Pilot plant study on the use of powdered activated carbons to remove various impurities from a sugar refinery liquor. In: Proceedings of the Advances in Sugar Crop Processing and Conversion 2018 Conference, May 15-18, 2018, New Orleans, Louisiana. 2:237-249.

Interpretive Summary: Prior laboratory studies identified a set of ideal treatment conditions to remove colorants, soluble and insoluble starch, as well as residual amylase enzyme from refinery liquors (syrups). Herein reported are pilot plant studies carried out to scale-up laboratory results. Clarified refined syrup, at 75 or 80°C was spiked with either 0.5 or 1 ppm of high temperature stable'a-amylase and treated with powdered activated carbon (PAC) at doses of 250, 500, or 750 ppm on a Brix basis. PAC effectiveness to simultaneously remove various impurities was monitored over 45 min to determine best performance conditions and confirm prior laboratory results. Amylase (protein) removal improved with PAC application rate, with an overall amylase percent removal (across residence times and amylase doses) of 81.8%, 84.8%, and 94.0% respectively for 250, 500, and 750 ppm of PAC at 75°C. Highest percent color removal of 37.9%, 42.5% and 55.1%, respectively for color compounds measured at pH 4, 7, and 9, occurred for 750 ppm PAC and 45 min residence time, across both syrup temperatures and amylase doses. A concomitant decrease in the indicator value (I.V.) of up to 21% at the 750 ppm PAC dose, was also observed. PAC was also able to decrease turbidity by 42% on average. The small-scale pilot plant unit was successfully utilized to perform scale-up studies yielding valuable information prior to large-scale industrial trials.

Technical Abstract: Prior laboratory studies identified a set of ideal treatment conditions to remove colorants, soluble and insoluble starch, as well as residual amylase enzyme from refinery liquors (syrups). Herein reported are pilot plant studies carried out to scale-up laboratory results. Clarified refined syrup, at 75 or 80°C was spiked with either 0.5 or 1 ppm of high temperature stable'a-amylase and treated with powdered activated carbon (PAC) at doses of 250, 500, or 750 ppm on a Brix basis. PAC effectiveness to simultaneously remove various impurities was monitored over 45 min to determine best performance conditions and confirm prior laboratory results. Amylase (protein) removal improved with PAC application rate, with an overall amylase percent removal (across residence times and amylase doses) of 81.8%, 84.8%, and 94.0% respectively for 250, 500, and 750 ppm of PAC at 75°C. Highest percent color removal of 37.9%, 42.5% and 55.1%, respectively for color compounds measured at pH 4, 7, and 9, occurred for 750 ppm PAC and 45 min residence time, across both syrup temperatures and amylase doses. A concomitant decrease in the indicator value (I.V.) of up to 21% at the 750 ppm PAC dose, was also observed. PAC was also able to decrease turbidity by 42% on average. The small-scale pilot plant unit was successfully utilized to perform scale-up studies yielding valuable information prior to large-scale industrial trials.