Production of hydrogen by steam gasification from lignin with Al₂O₃·Na₂O·xH₂O/NaOH/Al(OH)₃ catalyst

Some influencing factors on hydrogen production from steam gasification of lignin with Al₂O₃·Na₂O·xH₂O/NaOH/Al(OH)₃ catalyst in a fixed bed reactor were examined. The results show that the formation rates of hydrogen increase with increasing ratio of Na₂O/C and ratio of vapor to lignin as a whole. Higher flow rate of vapor is conducive to inhibit the generation of CO and CO₂ at lower temperature. H₂O(g) produced by the hydrates contained in the catalyst can bring on more Na+ and OH^- ions to be formed by dissociation of NaOH within the catalyst. This leads to more remarkable reduction of the C—H bond energies of lignin. The conversion degree of hydrogen of lignin at 473K~973K reaches 134.94%, which shows that the present catalyst has good catalytic activity on hydrogen production from steam gasification of lignin at low temperature.