Experimental investigation of catalytic cracking of rice husk tar for hydrogen production

The presence of tar content in the product gas is a major problem with the biomass gasification process as it prevents its further utilization. Heterogeneous cracking of tar using catalyst is the most effective way to overcome this problem. The present study provides specially a method for converting biomass to hydrogen-rich syngas in a two-stage process. The first stage refers to pyrolysis process and the second stage refers to gasification process. The heterogeneous experiments of rice husk tar cracking were performed in a two-stage gasifier using different catalysts such as char formed from pyrolysis of rice husk in the same reactor, commercial activated carbon, sand silica, and nickel containing stainless steel turnings obtained from mechanical workshop. The products of heterogeneous tar cracking were evaluated for optimizing hydrogen-rich syngas formation considering the effects such as temperature, carrier gas and quantity of catalyst. The mild steel turnings were found to be the best catalyst giving 0.31 vol% tar, 53.60 vol% of hydrogen, 22.73 vol% of carbon monoxide, 0.0 vol% of methane and 23.35 vol% of carbon dioxide in product gas at 900 °C.