Rapid pyrolysis of rice hull in a curie-point pyrolyzer

Rapid pyrolysis of rice hull was studied in a Curie-Point pyrolyzer with heating rates between 1500 and 2000°C s^-1, depending upon the Pyrofoil used. Primary pyrolysis occurred vigorously between 400 and 600°C to yield tar, light organics, H₂O, CO₂ and CO. As temperature went over 600°C a small amount of heavier primary products was further cracked into CO and light hydrocarbons. The amount of char residue decreased with temperature and finally reached an asymptote of 24%; this value was about 10% lower than that obtained in a slow heating thermogravimetric analyzer (TGA). Below 800°C the effect of residence time on rice hull devolatilization was significant whereas, at higher temperatures, the pyrolysis was so rapid that it virtually completed during the heating up period. Pyrolysis of cellulose and lignin yielded liquid tar and solid char, respectively, as the major products; the yield of char and total volatiles from the pyrolysis of rice hull could be estimated from their yields in the pyrolysis of cellulose and lignin.