The Effects of Different Catalysts on the Pyrolysis of Thistle, Onopordum Acanthium L.

Abstract

Fixed-bed fast pyrolysis experiments have been conducted on a sample of thistle, Onopordum Acanthium L. The experiments were performed in a fixed-bed tubular pyrolysis reactor to investigate the effects of sweeping gas flow rate and types of catalysts on the pyrolysis product yields. The optimal sweeping gas flow rate is 100 cm3 min−1. In order to increase the oil yield, biomass pyrolysis experiments were performed in a fixed bed reactor with two selected catalysts, namely sepiolite and clinoptilolite. All experiments were conducted in a nitrogen atmosphere with a heating rate of 300°C min−1, pyrolysis temperature of 550°C, and mean particle size of +0.6–0.85 mm. In the experiments, all the catalysts were used with various percentages, and the effects of the variable catalysts on the yields and chemical composition of the oils obtained were investigated. Oil yield reached 29.5% with the use of sepiolite and 32.1% with clinoptilolite, while it was only 18.9% without a catalyst. Chromatographic and spectroscopic studies on the pyrolytic oil showed that the oil obtained from thistle could be used as a renewable fuel and chemical feedstock.