Development of a General Theory of Intensified Reactive Separation for Palm Oil Refining Processes Using Dividing Wall Columns

The intensification of chemical processes through simultaneous reaction and separation in novel column configurations offers fundamental energy and capital cost reduction opportunities for the Nigerian palm oil refining industry, yet no theoretical framework exists in the literature for the systematic application of dividing wall column technology to oleochemical reactive separation systems. This study develops a general theory of intensified reactive separation for palm oil refining, focusing on the simultaneous esterification of free fatty acids and fractionation of crude palm oil in a dividing wall column. A rigorous rate-based equilibrium stage model was developed in gPROMS incorporating the UNIFAC thermodynamic model for fatty acid-glyceride-methanol systems, solid acid catalyst effectiveness factors for the esterification reaction, heat integration between divided sections, and dynamic column hydraulics. The theoretical framework systematises the design space for reactive dividing wall columns in terms of dimensionless separation-reaction interaction parameters that determine whether intensification delivers net energy reduction or operational instability. Steady-state multiplicity analysis using continuation methods revealed that the reactive dividing wall column exhibits up to three stable steady states in certain feed composition ranges, a phenomenon not previously reported for oleochemical systems. An original stability criterion is proposed for the operating region of interest. Experimental validation was conducted using a pilot-scale dividing wall distillation column with catalytic packing sections. Energy savings of 34 to 41% relative to conventional esterification-fractionation configurations were achieved in validated steady-state simulations. The study establishes the theoretical foundations for commercial dividing wall column implementation in Nigerian palm oil refining. Keywords: dividing wall column, reactive separation, palm oil refining, process intensification, steady-state multiplicity