Role of catalyst and its fluidization in the catalytic gasification of biomass to syngas at low temperature

The catalytic gasification of cellulose at much lower temperature than the usual methods such as noncatalytic and dolomite-catalyzed gasification became possible by the combination of the high-performance catalyst and fluidized-bed reactor. In the catalyst development, it is found that the Rh/CeO₂/SiO₂ with 35% CeO₂ content showed the best performance with respect to the carbon conversion and product distribution. Enough fluidization is very important for the removal of char deposition on the catalyst surface. In addition, the introduction of air from the bottom of the reactor is also very important because of the direct contact between the catalyst and oxygen molecule. The catalyst for this process has the high activity of combustion and reforming and the smooth redox properties. The fluidized-bed reactor plays important roles in the mixing of the catalyst and pyrolyzed products of cellulose and catalyst circulation between reduced and oxidized states. Almost no tar and char were yielded under the conditions of feeding rate = 12 g/h, equivalence ratio = 0.12, steam feeding rate = 1.80 g/h, and weight of catalyst/feeding rate of biomass = 0.25 h at 873 K, and this makes the process useful.