Pyrolysis of hazelnut shells in a fixed-bed tubular reactor: yields and structural analysis of bio-oil

Abstract

Fixed-bed pyrolysis experiments have been conducted on a sample of hazelnut shells to determine the possibility of being a potential source of renewable fuels and chemical feedstocks. The effects of pyrolysis temperature and well-sweep gas atmosphere (N 2) on the pyrolysis yields and chemical compositions have been investigated. The maximum bio-oil yield of 23.1 wt.% was obtained in N 2 atmosphere at a pyrolysis temperature of 500°C and heating rate of 7 K min −1. The pyrolysis products were characterised by elemental analysis and various chromatographic and spectroscopic techniques and also compared with currently utilised transport fuels by simulated distillation. Bio-oil was then fractionated into pentane soluble and insoluble compounds (asphaltenes). Pentane soluble was then solvent fractionated into pentane, toluene, ether and methanol subfractions by fractionated column chromatography. The aliphatic and low-molecular-weight aromatic subfractions of the bio-oil were then analyzed by capillary column gas-liquid chromatography and GC/MS. Further structural analysis of bio-oil and aromatic and polar subfractions FTIR and 1H-NMR spectra were obtained. The chemical characterization has shown that the bio-oil obtained from hazelnut shells was quite similar to the crude oil and shale oil.