Removal Of Novel Olefins From Aromatics With Modified-clay Catalysts

In this thesis, Linan clay and Yixian clay, which come from East China and Northeast China separately, were used in removal of trace olefins from aromatics. Activated clay samples were analyzed using the BET and pyridine-FTIR measurements to investigate their physical and chemical properties. The results showed that the Yixian clay, which has greater specific surface area and weak Lewis acid, has a higher activity and lifetime in removal of olefins. Modify Linan clay and Yixian clay with different Lewis acid and rare earth compounds to make a series of supported catalysts. The catalytic study showed that catalyst prepared with Lewis acid zeolite had the best catalytic activity and the longest lifetime in different Lewis acid compounds. The influence of loading amount and calcination temperature were also studied. BET, XRD, pyridine-FTIR characterization methods were used to investigate the change of structure, crystal form and acid property between clay and modified-clay catalysts. The influence of these change on catalytic activity and lifetime were discussed. The results showed that the modified-clay catalyst had a smaller specific surface area and increased weak Lewis acid amount, while the crystal form remained the same. The increase of weak Lewis acid amount could improve the catalytic activity and lifetime, while the increase of B acid restrained the reaction. The industrial test in Sinopec Qilu company showed that the lifetime of modified-clay catalyst was about5times as long as commercial clay. Temperature programmed Oxidation showed two kinds of different carbon deposition on deactivated catalyst. The regeneration experiments of deactivated catalyst showed that calcination couldn’t recover the activity of catalyst.