碳五粗异戊二烯选择性加氢非贵金属催化剂的制备OA

To address the high energy consumption and lengthy dual-extraction process for removing alkynes from C5 cracking fractions,a non-noble-metal selective hydrogenation catalyst Ni/Al2O3-MOx-TiO2(YN-5S)was developed to meet the demand for canceling the second extraction unit by selectively hydrogenating alkynes in C5 fractions.An Al2O3-MOx-TiO2 composite support was prepared by the co-precipitation method.The optimal preparation conditions for YN-5S catalyst were determined as follows:NiO content of 3A,MOx content of 3B,and carrier calcination temperature of 850℃.The catalyst exhibits high catalytic activity and high alkyne conversion.The catalyst was characterized by XRD,SEM,Py-FTIR,NH3-TPD,and TEM.The results show that the metal oxides in the support combine to form a uniform composite support.NiO is the main active component and is uniformly dispersed on the support surface.The catalyst surface predominantly contains L acid sites,exhibiting weak to medium acid strength.The appropriate medium-strong acidity and good dispersion of the active metal facilitate the activation of unsaturated bonds,thereby enhancing the hydrogenation activity of the catalyst.Under the conditions of 80℃,1.5 MPa,and LHSV of 1.5 h-1,crude isoprene from a petrochemical plant(0.1%(w)alkynes)is hydrogenated in one step to less than or equal to 0.001%(w)alkynes with minimal isoprene loss;activity remains undiminished after 1 000 h of continuous operation.The catalyst exhibits high tolerance to sulfur-and nitrogen-containing impurities,showing excellent resistance to poisons.It shows promise for industrial scale-up,providing a technical basis for eliminating the second extraction unit in C5 separation plants.