Influence of chemical pretreatment on the internal structure and reactivity of pyrolysis chars produced from sugar cane bagasse
The characterization of char obtained from the vacuum pyrolysis (8 kPa abs, 460 °C, 18 °C/min) of sugar cane bagasse followed by steam gasification (60 wt % of steam, 700-900 °C) was studied. The influence of different chemical pretreatments prior to pyrolysis (acetone, ethanol, HNO 3 and HF) on the ash content, the pore structure, and chemical composition of resulting chars and activated carbons were investigated. Changes in the pore structure were observed during the pyrolysis process and the steam gasification, namely, the development of a channel network and the increase of meso- and macroporosity distributions, respectively. These porous changes affect the pyrolytic yields. Clear influences of the surface area and ash content on the pyrolytic water yields and the inorganic devolatilization effect on the meso- and macropore distributions of chars were shown. Furthermore, the structural reorganization of chars obtained during the vacuum pyrolysis of HF and solvent-leached bagasse was beneficial to their reactivity toward steam gasification. © 2012 American Chemical Society.