The renewable energy prospect via pyro-oil blends of Chlorella vulgaris: A Feasibility study

Microalgae are selective polyphyletic entrants for industrial biomass production and microalgae-derived bio-fuels via pyrolysis have been attracted the research towards the commercial interest for improving their sustainability. In this present work, Chlorella vulgaris is considered to be a future sustainable source in favour of the production of bio-energy via transesterification and pyrolysis. The Chlorella vulgaris was pyrolyzed at three different temperatures, within the range of 550–650 °C. It was apparent that a maximum yield at 600 °C were 41.0, 32.0 and 27.0 %, respectively for pyro-oil, bio-char and pyro-gas. This study reveals the non-catalytic thermal pyrolysis of Chlorella vulgaris can produce a high complex pyro-oil composition of ethers, fatty acids, ketones, phenolics, etc., along with alkanes, aromatics, and nitrogenous compounds, from the carbohydrate, lipid, and protein fractions of the microalgae. Moreover, the pyro–oil characteristics were explained by means of GC–MS analysis, specific heat, spectral characterization viz FT-IR, UV–vis, 1H NMR and 13C NMR spectra. Further, enthalpy of vaporization, specific heat and dynamic viscosity of pyro–oil were evaluated. Besides, the Brake specific fuel consumption (BSFC), Ignition Delay (ID), pyro–oil-In–Cylinder pressure (PO-ICP) for the blends and petro-diesel were also examined. A minimum and maximum (NO)x emission observed at 25 & 100 % loads were of about 8.90, 8.24 and 9.24 & 16.25, 15.77 and 17.88 g/kWh, respectively for the CV-PO-B10, CV-PO-B15 blends and diesel. Additionally, the anti-oxidative and anticorrosion measurements of pyro–oil blends were performed. The blend CV-PO-B15 possesses comparable engine as well as emission characteristics.