Effect of Torrefaction on Thermal and Kinetic Behavior of Kenaf during Its Pyrolysis and CO Gasification.

Torrefaction is an appealing pretreatment method for improving the fuel properties of kenaf biomass before its utilization in thermochemical processes. This study evaluated and compared the impact of torrefaction on thermal behavior and kinetics during pyrolysis and gasification. Thermogravimetric analysis experiments were conducted at temperatures of 300-1173 K at several heating rates under N and CO atmospheres. The raw and torrefied kenaf (RK and TK) during CO gasification in the low-temperature region (<900 K) was found to exhibit a tendency that was similar to that of N. However, TK during CO gasification resulted in a lower maximum mass loss rate, delayed initiating temperature, and lower devolatilization index due to lower reactivity. In addition, the gasification reaction of CO and char was observed to occur in the high-temperature region (> 900 K), thus improving conversion efficiencies. The activation energy for TK in a CO atmosphere depending on the conversion was calculated using the distributed activation energy method. The activation of RK during CO gasification was higher than that of N. However, TK during CO gasification exhibited a lower activation energy compared to that of N, indicating its potential as a better feedstock during the CO gasification process and the ability to save energy.