Effects of Titania Based Catalysts on In-Situ Pyrolysis of Pavlova Microalgae

Abstract

Pavlova microalga was pyrolysed in presence of titania based catalysts in a fixed bed reactor at various temperatures. The effects of catalysts on Pavlova microalga pyrolysis were investigated. A large fraction of the starting energy (similar to 63-74% daf) was recovered in the bio-oils when the catalysts were used. The bio-oil yield was 20% higher in presence of Ni/TiO2 (22.55 wt%) at 500 degrees C. The High Heating Values of the produced bio-oils were in the range of similar to 35-37 Mykg and suffered strong deoxygenation, with O content (% daf) diminished from 51 wt% to similar to 9-12 wt%. The H-1 Nuclear Magnetic Resounance and Gas Chromatography Mass Spectrometry suggested that the titania catalysts enlarged the aliphatics and aromatic compounds and decreased oxygenates in the bio-oils. Ni/TiO2 had the greatest activity in increasing aliphatic protons (60%) and decreasing coke formation. Its enhanced cracking activity was due to its higher availability on the catalyst surface, compared to Co and Ce, and to strong interaction between Ni and TiO2 support. Despite the fact that the bio-oils were partially de-nitrogenated, the N-content still represent a major limitation for their use as bio-fuels without further upgrading. (C) 2017 Published by Elsevier B.V.