Catalytic Effects of MgSO4 and ZnCl2 On Fast Pyrolysis of Pine for the Production of Bio-Oils

The effects of MgSO4 and ZnCl2 as catalysts on fast pyrolysis of pine were investigated in a bench-scale bubbling fluidized bed reactor. The study showed that both MgSO4 and ZnCl2 could shift the pyrolysis of pine to a lower temperature zone , that is , most of pyrolytic reactions for cellulose and hemicellulose would happen at lower temperature while lignin at higher temperature , which results in different composition of bio-oils from that without adding any of these two salts. Compared to the bio-oils obtained without catalysts (base case) , glucopyranose in bio-oils was increased to 20.69 % from less than 1% (base case) when 20 wt% of MgSO4 was added; while ketones decreased from 26.71 % (base case) to 8.41 % , 2-Propanone , 1-hydroxy from 9.94 % (base case) to 0.62 %. When 30 wt% of ZnCl2 is added , glucopyranose in bio-oils hiked to 20.21 % from less than 1% (base case); while phenols reduced to 6.25% from 27.09 % (base case). The pH of bio-oils rises whether MgSO4 or ZnCl2 was added. This study suggests that by adding specific salts into biomass , the composition of bio-oils obtained from fast pyrolysis can be of greatly different. Therefore , we can increase the content of certain chemicals in bio-oils on purpose , which could make the extraction of value-added chemicals from bio-oils more feasible and economical.