LM Arévalo, JG Rodríguez, DF Teuta and NJ Gil
Colombian Sugarcane Research Center (CENICAÑA), Experimental Station, Cali-Florida Highway Km 26, Valle del Cauca, Colombia
Over the past 5 years, the Colombian sugarcane industry has faced rising impurity levels in cane supply due to increased mechanical harvesting (from 64 to 75%), fluctuating weather, and varying cultivation practices, resulting in a 2.3% decline in mixed juice purity and a 20% increase in final molasses losses by 2024 compared to 2019. To address these challenges, a three-fold strategy was implemented, focusing on material characterization, reducing impurity formation and addition, and improving impurity removal using processing aids. Impurity balances, including organic acids, minerals, and microbial metabolites, were conducted in three juice and five syrup clarification stations to identify critical points of impurity accumulation and generation. Control strategies were implemented in four mills to stabilize pH and mixed juice flow, with precise dosing of processing aids. The effectiveness of a terpen-based biocide in juices, along with the application of dextranase and surfactants in molasses, was evaluated under various conditions on laboratory and pilot scale to minimize the impact of impurities on sucrose recovery. Results showed significant variations in sucrose losses among mills (0.04 to 0.33 kg/t of cane), linked to operational practices. Classifying recirculation streams by soluble solids (Brix) and ensuring a hygienic equipment design proved effective in maximizing sucrose recovery. Clarification removed <10% of soluble impurities, highlighting the need for control strategies and complementary treatments. Implemented measures stabilized process variables (coefficients of variation below 7%), yielding sucrose recoveries of 0.03-0.05 kg/t of cane, reduced lime consumption, and decreased scaling in the evaporation train. Biocide application reduced mannitol production rates in raw juice by 87-91% and 30-64% in mixed juice. Dextranase and surfactant use significantly reduced crystal elongation by 27% and increased crystal growth rates (53.14 and 78.21 μm/h). This integrated approach effectively optimized key operational practices, stabilized critical variables, and enhanced production efficiency, providing robust solutions to reduce impurity impacts and improve sucrose recovery.