Abstract

This study investigates the effect of feedstock drying on the emissions of polycyclic aromatic hydrocarbons (PAHs) associated with the particulate matter (PM) produced during the co-generation of biochar and bioenergy. Raw pyrolysis volatile mixtures were generated from the pyrolysis of rice husk at 400, 500, 600, 700, and 800 °C using a laboratory-scale continuous pyrolysis-combustion system and combusted at 850 °C. PM samples from the combustion were collected and analysed for 15 priority PAH species with a gas chromatography/mass spectrometer (GC/MS). It was found that the utilization of the as received (AR) rice husk resulted in significantly greater energy-based yields of PM10 (1.2 times at 400 °C and 1.6 times at 800 °C) than the dried rice husk. The majority of the increase was of the PM2.1-10 size fraction. The PM-bound PAH concentration was found to be 2.1 and 2.8 times higher for the AR rice husk at 400 and 800 °C, respectively. This resulted in a significant increase in the energy-based yield of PAHs over the entire volatile production temperature range for the AR rice husk. Nevertheless, the majority of the PM-bound PAH species generated from the AR rice husk consisted of 2 and 3 ring PAHs (naphthalene, acenapthylene, and acenaphthene) with relatively low toxicity. The concentration of 4, 5, and 6 ring PAHs was generally lower than that generated from the dried rice husk. This resulted in the benzo(a)pyrene-equivalent toxicity of the PM generated from the AR rice husk being lower than the dried counterpart.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call