Pilot plant studies demonstrate the ability of a powdered activated carbon to simultaneously remove multiple impurities from a refinery syrup

Authors: Lima, Isabel; JIMENEZ, ANA - Carboua International; EGGLESTON, G - Audubon Sugar Institute; PABON, BENHUR - Carboua International; SARIR, EMMANUEL - Carboua International; THOMPSON, JACK - Lsr Refinery, Llc

Submitted to: Sugar Journal
Publication Type: Trade Journal
Publication Acceptance Date: 3/12/2021
Publication Date: 4/1/2021
Citation: Lima, I.M., Jimenez, A., Eggleston, G., Pabon, B., Sarir, E., Thompson, J. 2021. Pilot plant studies demonstrate the ability of a powdered activated carbon to simultaneously remove multiple impurities from a refinery syrup. Sugar Journal. MARCH-APRIL:13-20.

Interpretive Summary: This study reports on scaled up pilot plant studies on the ability of powdered activated carbon (PAC) to remove multiple impurities from sugarcane refinery streams. Clarified refined liquor, at 75 or 80°C, was spiked with either 0.5 or 1 ppm of high temperature stable a-amylase and treated with PAC at doses of 250, 500, or 750 ppm on a Brix basis. PAC effectiveness to simultaneously remove color and protein was monitored up to 45 min residence time to determine best performance conditions. Amylase (protein) removal improved with PAC application rate, with an overall amylase percent removal (across syrup temperatures and amylase doses) of 77.1%, 86.2%, and 87.3% respectively for 250, 500, and 750 ppm of PAC at 45 min. Highest percent color removal of 37.9%, 42.5% and 55.1%, respectively for color measured at pH 4, 7, and 9, occurred for 750 ppm PAC and 45 min, across both liquor temperatures and amylase doses. Significant adsorption of protein and color compounds occurred readily within the first 20 min. A concomitant decrease in the indicator value (I.V.) of up to 21%, at the 750 ppm PAC dose, was also observed. PAC followed by filtration with diatomaceous earth was also able to decrease turbidity by 42%. 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: This study reports on scaled up pilot plant studies on the ability of powdered activated carbon (PAC) to remove multiple impurities from sugarcane refinery streams. Clarified refined liquor, at 75 or 80°C, was spiked with either 0.5 or 1 ppm of high temperature stable a-amylase and treated with PAC at doses of 250, 500, or 750 ppm on a Brix basis. PAC effectiveness to simultaneously remove color and protein was monitored up to 45 min residence time to determine best performance conditions. Amylase (protein) removal improved with PAC application rate, with an overall amylase percent removal (across syrup temperatures and amylase doses) of 77.1%, 86.2%, and 87.3% respectively for 250, 500, and 750 ppm of PAC at 45 min. Highest percent color removal of 37.9%, 42.5% and 55.1%, respectively for color measured at pH 4, 7, and 9, occurred for 750 ppm PAC and 45 min, across both liquor temperatures and amylase doses. Significant adsorption of protein and color compounds occurred readily within the first 20 min. A concomitant decrease in the indicator value (I.V.) of up to 21%, at the 750 ppm PAC dose, was also observed. PAC followed by filtration with diatomaceous earth was also able to decrease turbidity by 42%.