Comparison between the "slow" and "fast" pyrolysis of tobacco residue

In this study, the trends in yields and product compositions of slow pyrolysis and fast pyrolysis were determined and compared with each other. Slow pyrolysis of tobacco residues with particles of between 0.425 and 0.850 mm were conducted in a fixed-bed tubular reactor with a heating rate of 7 degrees C min-(1) for various pyrolysis temperatures (400, 500, 550 and 700 degrees C) and various nitrogen flow rates (50, 100, 200 and 400 cm(3) min(-1)). The maximum oil yield was 27% at the pyrolysis temperature of 550 degrees C with the sweeping gas flow rate of 100 cm(3) min-(1). Increasing heating rate up to 300 degrees C min(-1) caused 10% increase of liquid yields. Chemical compositions of the oils were investigated by using chromatographic and spectroscopic techniques such as column chromatography, Fourier transform infrared spectroscopy (FT-IR), gas chromatography (GC), H-1 NMR and elemental analysis. Bio-oil obtained from fast pyrolysis has lower C distribution and higher H/C ratio than bio-oil obtained from slow pyrolysis. Consequently, the chemical characterization has shown that the obtained bio-oils could be used as conventional fuels. (C) 2007 Elsevier B.V. All rights reserved.