Effect Of Supports On The Deoxygenation Of Methyl Laurate Over Ni Based Catalyst

With the continuing depletion of the reserves of non–renewable petroleum and the worsening environment pollution,Grease,as a renewable energy,has attracted much attention.But amounts of oxygenates content in the grease limit their application.To convert triglycerides into hydrocarbons identical to petroleum fuels,eliminating oxygen atoms from grease is required.In this study,the deoxygenation of methyl laurate has been studied with a variety of supported Ni catalysts prepared by the excessive impregnation method at 280oC in the absence or presence of H₂,to explore the influence of the support?Al₂O₃,ZrO₂,C,HZSM-5,USY and H??.Methyl laurate is selected as model compound for grease.The product compositions have also been investigated by GC and GC-MS.The catalysts were characterized by means of XRD,NH₃-TPD,BET,SEM.Experimental results show that,methyl laurate is more likely to deoxygenation in H₂ than in N₂.Compared to other supports,three highly acidic molecular sieve supports gave higher conversion and total alkane selectivity.In the presence of H₂,Ni/HZSM-5catalyst showed a significantly high deoxygenation activity,producing 53.5%alkanes.The acidity of the carrier played a significantly role to deoxygenation activity.According to the analysis of intermediate product,the deoxygenation of methyl laurate in the absence of H₂ is decarboxylation,which generates C₁₁ hydrocarbons.In H₂,due to the dual role of nickel metal and the acidity of supports,a series of hydrogenation-hydrogenolysis-dehydration reaction generates C₁₂ hydrocarbons as main product.Hierarchical HZSM-5 zeolites were prepared using better performance HZSM-5zeolite as raw material by different concentration of NaOH aqueous solution pretreatment methods.The results show that,on hierarchical HZSM-5 supported Ni based catalyst,the conversion of methyl laurate and the yield of alkanes are improved.On Ni/HZSM-5-1.0 pretreatment by 1.0mol/L NaOH aqueous solution,the catalyst has the highest catalytic activity,the conversion is 89.5%and the total alkane yield is 81.5%.The life of the catalyst is also extended.