Experimental study and aspen HYSYS modeling of Jojoba biodiesel production and Wax Ester vacuum distillation

Abstract

Jojoba oil offers a sustainable biofuel alternative; however, its long-chain wax ester composition creates significant separation bottlenecks. This study utilizes an integrated experimental and computational approach to resolve these challenges. Laboratory transesterification achieved raw reaction yield of 89.64%, but standard gravity decanting failed because of persistent 1-Eicosanol emulsions. To overcome these physical limitations, the researchers developed an Aspen HYSYS model (NRTL package) to simulate an optimized two-stage vacuum distillation framework. Sensitivity analysis on the second column showed that increasing the distillation ratio (DR = 7.5–10.0) at a fixed reflux ratio (RR = 8) enhances Methyl Eicosenoate (ME) purity up to 97.50%, However, it is constrained by noticeable yield trade-offs. An optimal operating condition was established at)DR = 9.0, RR = 8), balancing ME purity (96.30%), process yield (80.89% relative to the maximum theoretical yield), and fuel viscosity (6.892 cSt). Thermophysical analysis at standard conditions (40 °C, 101.3 kPa) confirmed optimized fuel properties with a density of 852.00 kg/m 3 . The specific thermal energy consumption (STEC) was estimated at 1.917 kWh/kg of purified biodiesel. Recovering 1-eicosanol and recycling methanol may improve process utilization, whereas petroleum diesel blending (B10/B20) is recommended to achieve commercial compliance.