Effects of operating parameters on products yield and volatiles composition during fast pyrolysis of food waste in the presence of hydrogen

Abstract

Recently, the resource utilization of food waste is receiving more attention by government and scholars. In this investigation, the high-temperature fast pyrolysis in the presence of hydrogen of food waste carried out by the laboratory-scale downdraft tube reactor, to explore the impact of operating parameters including pyrolysis temperature (700–900 °C), carrier gas flow rate (100–250 mL min−1) and hydrogen content (0–15%). The products yields were calculated based on experimental results, it can be found that the yield of gas, bio-oil and bio-char under Run 6 (900 °C, 100 mL min−1 and 10% hydrogen) were 63.01%, 5.02% and 31.97%, respectively. The gas composition in volatiles at different conditions was detected by Gas Chromatograph, which can be inferred that increasing the pyrolysis temperature, shortening the carrier gas flow rate and improving the hydrogen content were beneficial to improve the gaseous product yield, quality and heating value. In the presence of hydrogen, the molar content of H2 and CH4 in gas increased significantly. Moreover, the bio-oil composition was analyzed by Gas Chromatograph/Mass Spectrometry, and the effect of operating parameters on product species and typical compounds were also explored in this investigation. The results showed that hydrogen can inhibit the formation of nitrogen-containing heterocycles and improve the selectivity of phenols in bio-oil during pyrolysis. It can be found that food waste pyrolysis in the presence of hydrogen can improve products yield and quality under the proper operating conditions.