Flue Gas CO2 Capture by Microalgae in Photobioreactor: a Sustainable Technology

This paper addresses the development of pilot scale sustainable technology for microalgae capture of CO2 from power plant flue gas in alkaline solutions to produce biodiesel from algal oil. A combination of computer tools for process simulation, economic evaluation, and environmental impact allow sustainable process assessment. Laboratory scale experiments for growth and culture for algae in laboratory photobioreactor are considered. Based on them, CO2 biocapture, biomass harvesting and algal oil extraction are evaluated. Process flowsheet for pilot scale CO2 biocapture from flue gas, growth and separation of biomass, as well as algal oil separation is implemented in SuperProDesigner (R) v8.5 simulator. Solvent is recovered by distillation and recycled. Experiment information allows to setup flowsheet, unit operations and unit procedures mass balance. As semi-batch process is considered, feedstock quantity/ flowrate and processing times are calculated. Process simulation predicts for similar to 1,400 kg CO2/y biocapture with similar to 45 % yield, similar to 200 kg algal oil/y is produced. Technology sustainability is evaluated by economic and environmental performance. Process economics is evaluated with SuperProDesigner (R) and environmental impact with WAR software tool.