Aqueous hydrolysis of tallow for the production of glycerin: Model development and study on parametric sensitivity

Abstract

Glycerin is produced by aqueous hydrolysis of tallow fat under high pressure and temperature in the absence of catalysts in a countercurrent extractor. A mathematical model describing the material and energy flows across different phases is formulated to study the degree of hydrolysis at different temperatures as well as at different feed raw material ratios. As the temperature and pressure play important roles in the degree of hydrolysis, it is necessary to understand the reaction mechanism and kinetics to find out the safer dynamics of the process. Degree of hydrolysis is found for different operating parameters under the influence of phase equilibrium. Mathematical model consisting of partial differential equation (PDE), ordinary differential equation (ODE), and algebraic equation representing mass and energy balances under both steady and transient operating conditions using first principle method are solved to find temperature profiles along the hydrolyzer which are validated using real-time data. The validation of process model using real plant data shows best fit ensuring the accuracy of process model with negligible model mismatch. Bifurcation/sensitivity analysis has been done to investigate the nature of process parameters.