Catalytic Pyrolysis of Waste Achyranthes Root Over Al-MCM-41.

This study examined the thermal and catalytic pyrolysis of waste Achyranthes Root (AR) using pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). The non-catalytic pyrolysis of waste AR produced various kinds of oxygenates, such as acetic acid, hydroxy propanone, furfural, phenol, cresol, guaiacols, syringols, and so on. By applying nanoporous Al-MCM-41 with acidic properties and mesopores to the pyrolysis of waste AR, the levels of furan and aromatic hydrocarbons production increased with a concomitant decrease in the other oxygenates. The formation efficiency of furans was improved further by increasing the amount of Al-MCM-41 applied to the catalytic pyrolysis of waste AR.

Kinetic analysis and catalytic pyrolysis of spent medicinal herb over HZSM-5 and HY.

In this study, the kinetic analysis on the pyrolysis of a spent medicinal herb, namely spent Achyranthes root, is performed using a thermogravimetric analyzer and a model-free kinetic analysis method, allowing the calculation of activation energy values without the assumption of kinetic model. Owing to the structural change of lignin and elimination of hemicellulose during the decoction of raw Achyranthes root, the thermogravimetric analysis results show a large difference between the derivative thermogravimetry curves of spent and raw Achyranthes roots. The average apparent activation energy value of spent Achyranthes root, obtained from the non-isothermal thermogravimetric analysis, are found to be lower than those of raw Achyranthes root. This comes as a result of the much lower content of hemicellulose in spent Achyranthes root caused by the hemicellulose elimination from raw Achyranthes root during the decoction process. The catalytic fast pyrolysis of spent Achyranthes root over HZSM5-30 (HZSM-5 with SiO2/Al2O3 = 30) and HY30 (HY with SiO2/Al2O3 = 30) was performed using a two-stage fixed-bed reactor system. The catalytic fast pyrolysis of spent Achyranthes root over both HY30 and HZSM5-30 produced the much larger amount of aromatic hydrocarbons, compared to the non-catalytic fast pyrolysis, with a parallel decrease of oxygen-containing pyrolyzates. Owing to its robust pore structure and high acidity, it was the HZSM5-30 that produced the highest quality oil during the catalytic fast pyrolysis of spent Achyranthes root, having higher selectivity of mono-aromatic hydrocarbons compared to HY30.