Kinetic analysis and parameter optimization of shrimp shell liquefaction

This study addresses the environmental issues caused by massive global shrimp shell waste by optimizing its liquefaction conditions and analyzing liquefaction kinetics at different temperatures. Liquefaction was conducted using polyethylene glycol 400-glycerol as the mixed solvent and concentrated sulfuric acid as the catalyst. Response surface methodology (RSM) was employed to optimize reaction temperature, liquefaction time, liquid-solid ratio, and catalyst dosage. A kinetic model based on chemical reaction kinetics and transition state theory was established to evaluate the effect of temperature on the liquefaction rate. The optimal conditions were 173 °C, a liquid-solid ratio of 14:1, a catalyst dosage of 7%, and a reaction time of 108 min, achieving a liquefaction rate of 42.35% ± 0.84%. The process was confirmed as a complex multistage reaction; the apparent rate constant rose with increasing temperature, and the activation energy was 64.52 kJ/mol. Kinetic analysis showed that activation Gibbs free energy, enthalpy, and entropy varied with temperature, suggesting the formation of activated complexes. Overall, shrimp shell liquefaction is a temperature-dependent multistage process, and the kinetic activation parameters lay a theoretical basis for revealing its liquefaction mechanism.