Hydrogen production from catalytic gasification of cellulose in supercritical water

Interests in large-scale use of biomass for energy and in hydrogen are motivated largely by global environmental issues. Cellulose and sawdust were gasified in supercritical water to produce hydrogen-rich gas in this paper, and Ru/C, Pd/C, CeO₂ paticles, nano-CeO₂ and nano-(CeZr) _xO₂ were selected as catalysts. The experimental results showed that the catalytic activities were Ru/C > Pd/C > nano-(CeZr) _xO₂ > nano-CeO₂ > CeO₂ particle in turn. Low-concentration sodium carboxymethylcellulose (CMC) (2-3 wt.%) was mixed with particulate biomass and water to form a uniform and stable viscous paste which can be efficiently gasified. The 10 wt.% cellulose or sawdust with CMC can be gasified near completely with Ru/C catalyst to produce 2-4 g hydrogen yield and 11-15 g potential hydrogen yield per 100 g feedstock at the condition of 500 °C, 27 MPa, 20 min residence time in supercritical water.