Synthesis of monoglycerides/diglycerides via glycerolysis of palm oil using multifunctional reactors

Abstract

Glycerolysis of palm oil is an important process for producing monoglycerides (MG) and diglycerides (DG) for food, pharmaceutical, and cosmetic applications. However, the reaction is often limited by mass transfer resistance between the immiscible glycerol and oil phases. In this study, the continuous glycerolysis of palm oil was investigated using a spinning disc reactor (SDR), a multifunctional reactor which enhances heat and mass transfer. The effects of rotational disc speed (R), total volumetric flow rate (Q), glycerol to oil molar ratio (G/O), and NaOH loading on glycerolysis performance were evaluated at a reaction temperature of 200 °C. Three-dimensional CFD simulations were performed to investigate the hydrodynamic behavior within the SDR. A partial cone disc (PC) was optimized using a design of experiments (DoE) approach, giving an optimum recess depth of 3 mm and cone angle of 60°. Under the optimum operating conditions; R of 1000 rpm, G/O of 3:1, NaOH loading of 0.3 wt.% and Q of 100 mL/min, the SDR equipped with a smooth disc achieved 88% oil conversion, 66% MG selectivity, and 58% MG yield with a residence time of less than 1 s. The optimized PC increased the average shear rate from 13,419 s-1 to 19,476 s-1, resulting in an increase in MG yield from 57% to 66% at 1500 rpm. An oscillatory baffled reactor (OBR) was also preliminarily evaluated for glycerolysis of palm oil. Although the OBR achieved higher oil conversion and MG yield, the SDR equipped with the optimized PC exhibited higher MG yield efficiency due to its rapid micromixing and short residence time. Overall, the results demonstrate that both SDR and OBR are promising intensified reactors for continuous glycerolysis, while the optimized PC significantly enhances SDR performance and provides useful insights for reactor design and scale-up.