Environmental Impact and Scalability of Utilizing Coal Fired Power Plant Flue Gas in Microalgal Biofuel Production

摘要

Large scale production of microalgal based biofuels will require the integration of point source CO_2 sources. Flue gas integration from coal fired power plants fulfills this requirement while providing an environmental service. Heavy metals inherent in coal will ultimately be introduced to the culture system. Introduction of heavy metals have the potential to impact growth and negatively impact the quality of biofuel and other products. Heavy metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn were added to microalgae (Nannochioropsis salina) growth medium at concentrations representative of 7-day growth periods using coal flue gas as the carbon source. Heavy metal introduction resulted in an average decrease of 52% in biomass yield and 19% in lipid content. Microalgae biomass was processed into biofuel through one of two different in-situ transesterification techniques. Total production of biofuel from the heavy metal contaminated system decreased by over 50% for both conversion types.