Mathematical Modeling of Hydrodynamic Cavitation as Low Energy Extraction Technique for Lipid Removal from Nannochloropsis sp.

Lipid extraction assisted by hydrodynamic cavitation (HCLE) is one of the promising processes with low energy requirements. This study aims to reduce the energy requirement using a discrete flow system and evaluate two models to calculate the volumetric mass transfer coefficient. The variations of the number of repetitions, cavitation number, microalgae concentration, and temperature have affected the energy requirement value.  The first model uses total lipid mass transfer approximation (Model 1) and the second uses separated lipid mass transfer approximation (Model 2). Based on Model 1 the value of total volumetric mass transfer coefficient ( ) f were 1.166 x 10-2, 3.113 x 10-3 and 1.285 x 10-3 min-1 with coefficient of determination (R2) is 0.9797. Whereas, based on Model 2 the value of volumetric mass transfer coefficient from disrupted microalgae ( ) were 1.131 x 10-2, 2.925 x 10-3 and 1.260 x 10-3 min-1 and from the intact microalgae ( ) was 0.051, 0.030 and 0.011 1/min with R2 of 0.9766. Both models gave a similar result. It was shown that lipid release from disrupted microalgae was dominant compared to the intact microalgae. Therefore, the discrete flow system of HCLE is a promising technique for extracting lipids from microalgae