Preparation Of Pt/A Zeolite Catalysts And Its Application In Selective Hydrogen Combustion In The Presence Of Propane And Propylene

Propylene is an important chemical raw material.With the gap between propylene demand and supply expanded and the price of propane reduced in recent years,propane to propylene technology has become the third largest source of propylene production.Among the three technologies of propane to propylene,propane dehydrogenation-selective hydrogen combustion(DH-SHC),taking advantage of selective oxidation technique to remove hydrogen in the process of propane dehydrogenation should be beneficial to both the reaction equilibrium and the supplement of heat and steam to catalyst bed as well.The propylene productivity and the catalyst life could thereby be promoted while the energy consumption could be cut down.In the present study,the effects of support structure,Pt deposition position and Pt loading process on the structure and performance of Pt/A zeolite catalysts were studied in DH-SHC process.Firstly,by means of manipulating zeolite support structure and studying its effects on the performance of catalysts,the independent reactions on catalyst in different temperature range were clarified,and the reason for good performance of Pt/3A was revealed.On this basis,the effects of Pt deposition position on catalytic behavior were investigated.The activity and selectivity of the catalyst were improved by reducing the deposition of Pt outside pore channels of 3A zeolite.Finally,the effects of Pt loading process especially Pt loading amount on the structure and performance of catalysts were studied.The relationship between Pt loading amount and Pt atoms distribution as well as catalytic performance was established.Eventually,a simple and efficient catalytic system with low Pt expense for the SHC process was built.The high activity(96.6%)and high selectivity(100%)for SHC can be achieved on 0.5 wt.%Pt/3A at 300℃.