Selection of Microalgae Harvesting Technology for Bio-crude Oil Production

Abstract

Energy consumption of fossil fuel which keeps increasing has led to the urgency of research and development on the field of renewable energy for the future. Microalgae are considered to be the most promising new source of biomass compared with first and second-generation feedstocks. A great challenge is a choice of an effective approach for microalgae harvesting. Additional challenges of microalgae harvesting come from the small size of microalgae cells (3-30µm) and the similarity of the density of the microalgae cells to the growth medium. This research is aimed to determine the appropriate microalgae harvesting technology for bio-crude oil production. Several potential microalgae harvesting technologies are centrifugation, filtration, inorganic flocculation, organic flocculation, bioflocculation, electrocoagulation, and flocculation-sedimentation. The method used in this research is Analytic Hierarchy Process (AHP). The results indicate that the parameters taken into consideration are energy need (0.339), cost (0.214), risk of contamination (0.098), efficiency (0.133), technology availability (0.066), microalgae strain flexibility (0.079), and production time (0.071). In a case study, the pairwise comparison of seven alternatives each for the harvesting and seven criteria are compared. The best alternative that can be recommended as a microalgae harvesting technology is flocculation-sedimentation with a weight of 0.202.