CO2 as a gasifying agent for gas production from pine sawdust at low temperatures using a Ni/Al coprecipitated catalyst

Catalytic CO2 gasification of pine sawdust has been carried out at a relatively low temperature, 700 degreesC, and at atmospheric pressure. The Ni/Al catalyst used was prepared by coprecipitation and calcined at 750 degreesC for 3 h. The influence of the catalyst weight/biomass flow rate (W/mb) ratio on product distribution and gas composition was analyzed. Using a CO2/biomass ratio of around 1, the increase of the W/mb ratio increases H-2 and CO yields while CH4 and C-2 yields decrease. Deactivation of the catalyst was also observed under the experimental conditions employed. The influence of the W/mb ratio on the initial gas yields has been also analyzed. For W/mb ratios greater than or equal to 0.3 h, no significant modifications are observed on the initial yields of different gases, and it is confirmed that under these conditions the initial gas composition is close to that for thermodynamic equilibrium. The influence of the reaction atmosphere on gas yields has also been carried out, analyzing the results obtained in pyrolysis, steam gasification and CO2 gasification. (C) 2001 Elsevier Science B.V. All lights reserved.