Abstract
Decomposition of Japanese cypress volatiles has been found to proceed efficiently under a prepared Ni loaded brown coal (LY-Ni) char at extremely low temperatures around 400–450°C. This temperature range is much lower than conventional gasification methods (600–800°C for catalytic and 800–950°C for non-catalytic). For the low temperature decomposition of biomass volatiles, the LY-Ni coal with about 20 wt% Ni loading content by ion-exchange and impregnation methods showed a higher activity when compared with the lower LY-Ni coal by ion-exchange only and the higher Ni content of 27 wt%. Nickel particles in the 20 wt% LY-Ni coal dispersed well in the brown coal, with a mean particle size of 5 nm after devolatilization treatment at temperatures of 400–500°C. In the presence of 20 wt% LY-Ni char, tarry materials converted fairly significantly into gases so that the carbon amount in tarry materials was less than 2% (based on carbon). Compared with the cases of sand, the LY-Ni char increased the total gases, mainly including H2, CO, CO2 and CH4, by 3.5–4.5 times, and hydrogen practically by 5.4–6.9 times at decomposition temperatures of 450 to 600°C. Steam addition advanced the tarry materials gasification and carbon conversion into gas products greatly.
