The influence of pyrolysis conditions on yield and microporosity of lignocellulosic chars

Chars were prepared from lignocellulosic precursors (plant tissues) by pyrolysis under argon at varying heating rates to final temperatures of 500–900°C. Char yield was found to depend on precursor composition, heating rate below 500°C, and the final temperature attained. Char microporosity, determined by adsorption of CO₂ at 298 K, was found to be relatively independent of the precursor composition and pyrolysis heating rate. The basic microstructure defining the micropore system appeared to be formed by 500°C, although access to the pore volume was restricted at such low temperatures by mass that would be volatilized at higher temperatures.