Catalytic Cracking of Biomass High-Temperature Pyrolysis Tar Using NiO/AC Catalysts

Nickel oxide supported on activated carbon (NiO/AC) catalysts were prepared and used for catalytic cracking of tars from inert high-temperature pyrolysis of biomass. Rice husk was selected as the feedstock, and pyrolyzed at 800 degrees C using a lab-scale pyrolysis set. The pyrolysis vapors were subjected to either thermal cracking or catalytic cracking under 500-700 degrees C. The results indicated the thermal cracking was not very efficient to convert the tars, while the catalytic cracking reduced both the light and heavy tars significantly. The yield of the light and heavy tars were decreased from 4.4 wt% and 1.9 wt% in the non-catalytic process to 0.2 wt% and 0.1 wt% in the catalytic process by the NiO/AC (4.3 wt%) at 700 degrees C. The catalytic cracking also increased the gas product remarkably, mainly the H-2 and CO2. The catalytic performance of the NiO/AC catalyst could enhance at elevated catalytic temperatures and increased NiO content of the catalyst.