| Popis: |
Catalytic cracking is the major source of light olefins. And it is proved that some aromatics can also be obtained via catalytic cracking. Products are always impacted by many factors, especially catalysts. After a long time of development of industrial and commercial catalysts, a general kind of catalysts used in FCC (Fluid Catalytic Cracking) process is molecular sieves. Zeolites molecular sieves are normally applied to enhance the products of light olefins and BTX(Benzene-Toluene-Xylene). This paper highlights some methods to improve the zeolites from different perspectives based on those conditions that can affect zeolites. Some characteristics are discussed like structure, acid sites, acidity, etc. Besides, the cost of synthesis and regeneration should be considered as well. Some ideas about the modification of zeolites are summarized in this article like ion exchange of zeolites by rare earth metals or acids, which all prove the great success of improvements of zeolites. Olefin and BTX production increase effectively with these modified catalysts. There will be more kinds of catalysts in the future by combinations and modifications. |
