Catalytic pyrolysis of several kinds of bamboos over zeolite NaY

The catalytic pyrolysis of four kinds of bamboo, Neosinocalamus affinis, Pubescens, Bambusa rigida and Dendrocalamus latiflorus, was performed in a fixed bed reactor in an inert atmosphere of nitrogen at 773 K and 873 K for 10 h using zeolite NaY as catalyst. For Neosinocalamus affinis and Pubescens, the influence of pyrolysis temperature on the product distribution was also studied over the temperature range of 573-873 K at an interval of 50 K. As the pyrolysis temperature increases, the yield of gaseous products increases, while the yield of liquid products goes through a maximum value, and the amount of residue reduces. For the four kinds of samples, the liquid yield at 873 K increases to 64.1-68.8 wt% in the presence of NaY catalyst, in compared to that of 19.7-53.3 wt% from direct pyrolysis. In addition, the non-catalytic liquid contains numerous species including mainly carboxylic, carbonylic, lactonic, phenolic and furan compounds, while the catalytic liquid contains markedly reduced number of species composed mainly of carboxylic and carbonylic compounds, of which acetic acid is the major component. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the catalysts before and after use at 873 K. The results show that during the pyrolysis the NaY catalyst interacts with the primary pyrolysis intermediates of bamboos and thus leads to in situ reconstruction involving the impairment of [111] and [220] planes, and the enhancement of the [311] plane.