以天然凹凸棒石为原料合成Fe/Ti-ZSM-5沸石分子筛及其催化裂化性能

以天然凹凸棒石为硅源、铁源和钛源,一步合成了Fe/Ti-ZSM-5分子筛.X射线衍射、扫描电镜和N₂吸附等温线测定结果表明,所合成的样品具有良好的结晶度和较大的比表面积;NH₃程序升温脱附和H₂程序升温还原结果表明,该样品具有强的酸性和氧化还原性能.更为重要的是,与常规方法制备的ZSM-5沸石相比,Fe/Ti-ZSM-5在催化裂解原料油(LGO,加拿大)的测试中,丙烯的产率提高0.21%,总轻烯烃的产率提高0.33%.由此可见,Fe与Ti物种在ZSM-5沸石分子筛中的存在有利于提高轻烯烃的产率,有望在石油炼制过程中提高烯烃产率.

Synthesis and catalytic cracking performance of Fe/Ti-ZSM-5 zeolite from attapulgite mineral

Fe/Ti-ZSM-5 zeolite was synthesized successfully from treated attapulgite (ATP). This mineral consists of amorphous silica containing Fe and Ti species. X-ray diffraction patterns, scanning electron microscopy images, and nitrogen sorption isotherms indicate that the sample has a typical MFI structure, high crystallinity, and large specific surface area. Temperature-programmed desorption of ammonia and H₂ temperature-programmed reduction indicates that the Fe/Ti-ZSM-5 zeolite is strongly acidic and has superior redox properties. More importantly, compared with conventional ZSM-5 zeolite, Fe/Ti-ZSM-5 performs well, resulting in an increase in yield of 0.21% propylene and 0.33% total light olefins in the catalytic cracking of Canadian LGO (light gas oil). These results suggest that the presence of Fe and Ti species in ZSM-5 zeolite is favorable for enhancing light olefin yields, which is potentially important for oil refining in the future.