Production of hydrocarbons from a green algae (Oscillatoria) with exploration of its fuel characteristics over different reaction atmospheres

Abstract

Authors conducted non-catalytic, catalytic, and hydropyrolysis at 550 °C temperature and 1 bar pressure to produce biofuels from an ignored algal biomass of Oscillatoria by thermo-chemical degradation study in a tubular reactor having an internal diameter of 25 mm and 300 mm of active length covered by a furnace of a single heating zone. The catalysts used for the catalytic pyrolysis and hydropyrolysis study are TiO2: ZnO on 1:1 basis. Characterization of bio-oils by Fourier Transform Infrared Spectroscopy (FTIR) shows substantial variation in functional groups of all three types of bio-oils. Gas Chromatography-Mass Spectroscopy (GCMS) gives a detailed list of available hydrocarbons in bio-oil samples and proton NMR confirms the functionality of bio-oil by available proton assignments. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) shows morphology and the structural analogy of biochars with respect to biomass. Calorific values of three types of bio-oils ranges from 16.597 to 16.664 MJ/kg; and revealed that this particular biomass has potential as a resource of feedstock with an approximate yield of one-third of biomass on the dry weight basis. The pH of these bio-oils obtained from green algae varies in the range of 8.25 to 6.07 that indicates the less number of oxygenated compounds unlike very low pH bio-oils obtained from other types of biomass feedstock. Additionally, present results revealed that these bio-oils include formative compounds of most popular hydrocarbons, i.e., benzene, toluene and xylene (BTX). Further, they also include furans, phenols, benzaldehyde, guaiacol, caprolactam, styrene, oximes, etc. which can be used as green chemicals.