The Study On Isomerization Of N-heptane Over Mo₂C/Different Molecular Sieve

With the stringent environmental regulations and people's awareness of environmental protection gradually increased,the petroleum industry has paid their attention to energy conservation and environmental protection.In the petroleum industry,isomerization can not only improve the octane number of gasoline and the quality of oil,but also can improve our living environment.Under the condition of high temperature and high pressure,n-heptane is more likely to cause spontaneous combustion,resulting in the phenomenon of shock explosion,and the octane number of n-heptane is zero.So heptane isomerization has received widespread concern.The main catalysts of n-heptane isomerization are Pt and Pd supported on molecular sieves?SAPO-11,Y,beta,etc.?.Molecular sieves have good pore size distribution,suitable acidity and good metal dispersion.Because of the scarcity of precious metals such as Pt and Pd,molybdenum carbide is chosen to replace precious metal Pt and Pd,and has the properties of resistance to sulfur and nitrogen and resistance to roasting.In this paper,SAPO-11,USY,H-Mordenite?H-MOR?were used as the catalyst support,then ammonium molybdate was impregnated on the support,then Mo₂C/SAPO-11,Mo₂C/USY,Mo₂C/H-MOR catalyst are prepared.The effects of the content of Mo,calcination temperature,reduction temperature,reduction time,carbonization temperature,carbonization time and heating rate on the catalytic performance of n-heptane isomerization were investigated for Mo₂C/SAPO-11,Mo₂C/USY and Mo₂C/USY And the reaction conditions were investigated.Under the same conditions,the effect of three catalysts on the catalytic performance of n-heptane isomerization was compared,and the optimum n-heptane isomerization catalyst was found out.The results showed that the content of Mo was 3%,the calcination temperature was 550?,the reduction temperature was 450?,the reduction time was 4h,the carbonation temperature was 700?,and the heating rate was 2?/min.The optimum isomerization catalyst was Mo₂C/SAPO-11 zeolite catalyst.The conversion and isomerization selectivity of n-heptane were 69.28% and 74.53%,respectively.