Ni/HZSM-5催化热解玉米秸秆制取生物油的研究

Study on production of bio-oil by catalyst fast pyrolysis of corn stalks using Ni/HZSM-5

在固定床中考察Ni/HZSM-5对生物质催化热解的影响,采用浸渍法制备Ni负载量不同的Ni/HZSM-5分子筛催化剂,通过粒度分析、SEM、XRD和BET表征催化剂,在不同催化剂条件下热解玉米秸秆制取生物油,对生物油的理化特性和液相产物的化学组成进行分析.结果表明,Ni在HZSM-5表面负载均匀,Ni改性未影响HZSM-5的晶体结构,改性HZSM-5的比表面积随着Ni负载量的增加而减小.与不加入催化剂相比,在HZSM-5作用下得到的生物油得率降低,同时,酸类、醛类、呋喃类等含氧化合物的含量降低,酚类的含量增加;在Ni/HZSM-5作用下,与在HZSM-5作用下相比,所得生物油的得率上升,含水率下降,酮类含量明显降低,酚类含量进一步提高,说明Ni改性HZSM-5分子筛对生物质热解产物中的酮类、酚类含量具有明显的调控作用.

In this study,Ni was selected to modify the HZSM-5 zeolite for further improving the production and quality of bio-oil derived from biomass catalytic fast pyrolysis (CFP).The Ni/HZSM-5 samples prepared using impregnation method were characterized with laser particle size analyzer,SEM,XRD and BET.The influence of Ni/HZSM-5 on the physicochemical properties of bio-oil and chemical compositions of aqueous phase were investigated.The results showed that the crystalline structure of HZSM-5 was not affected by the modification process,and a uniform distribution of Ni on HZSM-5 surface was achieved.Meanwhile,the BET surface area of modi-fied Ni/HZSM-5 decreased with Ni loading amount increasing.Compared with non-catalytic fast pyrolysis (non-CFP),the bio-oil yield decreased significantly during CFP process with original HZSM-5.Besides,the relative contents of acids,aldehydes and furans (oxygenated organic com-pounds)in bio-oil decreased,while the relative contents of alcohols and phenols in bio-oil in-creased significantly.Additionally,the modified Ni/HZSM-5 increased the bio-oil yield in con-trast with original HZSM-5.Moreover,the relative content of ketones in bio-oil reduced dramat-ically and the relative content of phenols further increased,indicating that Ni/HZSM 5 has obvi-ous control effect on the production of ketones and phenols in biomass pyrolysis products.