Product sampling during transient continuous countercurrent hydrolysis of canola oil and development of a kinetic model

• A kinetic model for continuous triglyceride hydrolysis was developed based on lab-scale experimental data.
• All neutral components from hydrolysis experiments were quantified through GC-FID.
• Thermodynamic estimations were applied to determine the equilibrium constants.
• The model predicted experimental results within uncertainties for most of the data.
• The model suggested that diglycerides accelerated the transition from emulsive to rapid hydrolysis.

A chemical kinetic model has been developed for the transient stage of the continuous countercurrent hydrolysis of triglycerides to free fatty acids and glycerol. Departure functions and group contribution methods were applied to determine the equilibrium constants of the four reversible reactions in the kinetic model. Continuous countercurrent hydrolysis of canola oil in subcritical water was conducted experimentally in a lab-scale reactor over a range of temperatures and the concentrations of all neutral components were quantified. Several of the rate constants in the model were obtained by modeling this experimental data, with the remaining determined from calculated equilibrium constants. Some reactions not included in the present, or previous, hydrolysis modeling efforts were identified from glycerolysis kinetic studies and may explain the slight discrepancy between model and experiment. The rate constants determined in this paper indicate that diglycerides in the feedstock accelerate the transition from “emulsive hydrolysis” to “rapid hydrolysis”.