Experimental Study On Catalytic Pyrolysis Of Arundo Donax To Bio-oil

As a huge ouput of energy grass plant,Arundo donax is widely distributed,and has a strong ecological adaptability,however,only a few researchers have studied its feasibility as a pyrolysis material and improving the quality of the bio-oil.The fast pyrolysis and catalytic pyrolysis of Arundo donax was conducted in a two-stage fixed-bed reactor in order to explore the effect of the pyrolysis parameter on the product distribution,and the influence of the catalysts on the bio-oil quality in this work.The results of the fast pyrolysis of Arundo donax showed that the pyrolysis temperature was the most important pyrolysis parameter that had a graet influence on the product disrribution.When the pyrolysis temperature was increasing from 400 ? to 600 ?,the yields of the liquid firstly increased and then decreased,and the maximum value of 49.53 wt% was obtained at 500 ?.The yields of the liquid were also affected by the nitrogen flow rate and the particle size.Synthetically considering the results,the maximum value of the liquid was obtained at 500 ?,with the nitrogen flow rate of 300 mL/min and the particle size of 0.18~0.5 mm.Moreover,the pyrolysis temperature also has an important effect on the compositions of the gas and the bio-char.With increasing the pyrolysis temperature,the higher heating value(HHV)of the bio-char increased,and the maximum value of 24.71 MJ/kg was obtained at 600 ?.In order to improve the quality of the bio-oil,catalytic pyrolysis of Arundo donax was carried out in a two-stage fixed-bed reactor with the HZSM-5.The experments were to explore the effect of catalytic temperature,the height of catalysts and the Si/Al of the HZSM-5 on the compositions of the bio-oil.The results showed that:with considering the cost of the catalysts,the yields of the bio-oil and its quality,the catalytic effect was the best when the Si/Al was 50,with the catalytic temperature was 500 ? and the height of catalysts was 10 cm.The content of the oxygenates in the bio-oil that obtained at this conditions was decreased compared to the the bio-oil obtained from direct pyrolysis.The content of the aromatics increased to 29.47%,the amount of the oxygen decreased to 28.26 wt% and the HHV increased to 29.21 MJ/kg.It can be concluded that the quality of bio oil is effectively improved by catalytic pyrolysis.To improve the quality of the bio-oil,HZSM-5 with the Si/Al of 50 was used as the the support for loading metals including Mo,Zn,Fe,Zn and Cu,and the effects of this modified catalysts on the quality of the bio-oil were studied.The results showed that the Mo-Zn/HZSM-5 had the best performance in improving the quality of the bio-oil,and it was maimly displayed in the following aspects: the content of the xygenates decreased to 21.60%,the amounts of the aromatics increased to 37.29%,and the mnocylic aomatics was up to 28.77%,the HHV was reached 34.12 MJ/kg.