Catalytic Fast Pyrolysis of Bamboo over Micro‐mesoporous Composite Molecular Sieves

Abstract

AbstractTo upgrade biocrude oils from biomass pyrolysis, a novel micro‐mesoporous composite molecular sieve with HZSM‐5 structure as the core and MCM‐41 structure as the shell is synthesized and utilized. The synthesized hierarchical catalyst is characterized using X‐ray diffraction, N2 adsorption–desorption measurements, and transmission electron microscopy. Catalytic fast pyrolysis of bamboo over the composite molecular sieve is implemented using quantitative pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS). The experimental results demonstrate that the highest relative content of hydrocarbons (34.41 %) is obtained at 600 °C when bamboo is pyrolyzed by only HZSM‐5, which has significant shape‐selective effect on the products of aromatic hydrocarbons but is easily coked. When a two‐layer catalyst bed of MCM‐41 and HZSM‐5 is used to obtaining higher catalytic activity, the two‐layer catalyst bed is capable of the promotion of hydrocarbon production with a relative content of 41.44 % because the hierarchical catalyst has higher flexibility than the two‐layer catalyst bed. It is found that the concentration of alkali solution used significantly influences the catalytic effects of composite molecular sieve. Additionally, the catalyzed transformation of oxygenated chemicals into hydrocarbons can be facilitated with the utilization of hexadecyl trim‐ethyl ammonium bromide (CTAB) in comparison with NaOH.