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.