Catalytic gasification of pine-sawdust: Effect of primary and secondary catalysts

Abstract Pine sawdust steam gasification in a fixed double bed reactor and continuous flow was investigated. K 2 CO 3 as primary catalyst and cobalt supported on γ-Al 2 O 3 and SiO 2 -Al 2 O 3 as secondary catalyst was investigated. Thermal and catalytic steam gasification was compared. The effect of the support in tar yield and the H 2 /CO ratio was pursued. It is noteworthy to observe that the primary catalyst increases the biomass gasification. It is also marked the total consumption of CH 4 species by the primary catalyst. The catalysts (K 2 CO 3 and K 2 CO 3 -Co/γ-Al 2 O 3 ) reduced tar formation from 11% in the thermal gasification to a value of 2.0% and 0.5% respectively. This tar yield reduction could be explained due to the action of potassium actives species of the primary catalyst combined with the lower acid strength of the support; high metal dispersion of cobalt species and the higher fraction of metallic cobalt species in Co/γ-Al 2 O 3 catalyst. The catalysts decrease the formation of CO 2 from 21% in the thermal gasification to values on the order of 3%. The highest H 2 /CO ratio with a value of 1.6 was obtained by K 2 CO 3 -γ-Al 2 O 3 catalytic system. The presence of cobalt supported catalysts favored hydrogen consumption reactions such as reverse water gas shift reaction.