Kinetic Characteristic Of Acetylene Hydrogenation Over Supported PdCatalysts

Hydrogenation of acetylene is an important purification reaction for ethylene production in which the concentration of acetylene is lowered from 1 vol% to several ppm. Since the change of concentration cross four orders of magnitude, it’s difficult to build a kinetic models. In this thesis, the microkinetic analysis method is adopted to build a kinetic model applicable to wide operation ranges. DFT results of catalytic hydrogenation of acetylene over Pd(111) obtained by different groups are used as the sources of microkinetic parameters and the a set of parameters is chosen according to the kinetic experimental results obtained over a real Pd/Al2O3 catalyst with a Pd particle size of 3.4nm, the experimental data is obtained under a series of reaction conditions(C2H2,0.6%～0.9%; C2H4,65%～75%; H2,1.5%～1.8%; T, 75℃～80℃). A macrokinetic model and the relevant parameters is then deduced directly from the microkinetic analysis results. The obtained kinetic model is as following: It’s found that this kinetic model can well predict the kinetic results collected outside the original kinetic experimental condition range(H2>1.4%, C2H2<0.9%). The model can also be used for Pd/Al2O3 catalyst with a particle size of 1.6nm. But, the kinetic model is not suitable for kinetic experimental over the Pd/Al2O3 catalyst with a particle size of 6.2nm...