Investigation on chlorella Sp. HS2 microalgae growth using CO₂ from engine exhaust to study carbon sequestration

A functional method of exploiting engine exhaust waste has been explored in current investigation. In experimentation, a direct injection (DI) 4-stroke diesel engine has been considered. The engine was operated at varying injection pressures and injection timings. The exhaust emissions such as CO₂, NO, HC, and CO were determined at different engine load conditions. To capture CO₂ emissions at an optimal temperature desired for microalgae cultivation within a designed photobioreactor (PBR) tank, a shell and tube type heat exchanger was designed and operated to cool exhaust gases. Highest volume of CO₂ produced through the engine exhaust was used to cultivate Chlorella sp. HS2 microalgae. The results of biomass productivity and growth rate were compared for photobioreactor tanks, one with CO₂ supplementation and the other without any external CO₂ supply. The results derived in this study depict the effective usage of exhaust gases to harness CO₂ in the form of microalgae.