Abstract: Online catalytic upgrading of vapors from vacuum pyrolysis of biomass was performed on MCM-41. The effects of operating parameters including catalyzing temperature, catalyzing bed height and system pressure on the organic yields were inverstigated. The optimization of organic phase yield was further conducted by employing response surface methodology (RSM). Analysis of physicochemical properties, composition of organic phase in bio-oil and durability analysis of catalyst were also carried out. The results showed that operating parameters had significant effects on the yield of organic phase. The yield firstly increased and then decreased with the increment of catalyzing temperature and catalyzing bed height, and decreased as system pressure increased. When catalyzing temperature was 502℃, catalyzing bed height was 2.7 cm and system pressure was 7 kPa, the yield of organic phase reached 15.84% and the high heat value of organic phase was 31.08 MJ/kg. After catalytic pyrolysis of biomass with MCM-41, the aliphatic hydrocarbons and alcohols in organic phase increased significantly, while the contents of aromatic and carbonyl compounds reduced at the same time. Durable research of MCM-41 zeolite found that when the catalyst used for 100 min, the index of physical and chemical properties of bio-oil had decreased dramatically. This indicated that the quality of bio-oil had deteriorated significantly. Meanwhile, the weightlessness of catalyst had significantly increased. It suggested that the coke deposited on the catalyst had increased gradually and the catalytic activity had decreased significantly till the catalyst completely lost its activity.

Key words: biomass, organic phase yield, response surface methodology (RSM), durability, MCM-41