H Y/MC M-41分子筛的制备及改性后在吸附脱硫中的应用

摘要

采用附晶生长法合成了 HY/MCM-41复合分子筛,利用 X射线衍射仪(XRD)、N2吸附脱附、扫描电镜(SEM)、透射电镜(TEM)、智能重量分析仪(IGA)、吡啶原位红外(Py-IR)等技术对其物化性质进行了表征,发现HY/MCM-41复合分子筛具有微孔和介孔的双重孔道分布,且形貌为核壳结构。通过对金属 Ce离子改性制得吸附剂的吸附脱硫性能考察,发现固相研磨法改性的吸附剂在空速为5 h-1时吸附穿透硫容量可达1.81 mg/g,大于液相离子交换法改性的吸附剂吸附穿透硫容量1.32 mg/g。采用静态间歇法时,固相改性的吸附剂的脱硫率可达90.6%,高于液相改性的吸附剂脱硫率81.2%。同时发现,吸附剂表面的 B酸对吸附脱硫有着抑制作用,而 L 酸尤其是弱的 L酸的酸量与吸附脱硫性能有着正相关关系。%HY/MCM-41 meso-micro-porous composite materials composed of a core of HY zeolite and a thin layer of MCM-41 have been synthesized by the overgrown crystallization.The samples were characterized by means of X-ray diffraction (XRD),N2 adsorption-desorption,scanning electron microscope (SEM),transmission electron microscope (TEM),Pyridine in situ infrared (Py-IR)and Intelligent Gravimetric Analyzer (IGA)instruments.It was found that the composite material exhibited both properties of mesoporous MCM-41 and microporous HY-zeolite sieves.Adsorptive desulfurization performances of Ce ion supported over the synthesized composites as a sulfur adsorbent were evaluated.It was found that when the adsorbent was prepared by a solid-state grinding method with sulfur capacity of 1.81 mg/g can be obtained.While for the liquid ion exchange method,only 1.32 mg/g sulfur capacity can be reached.Through the batch methods it is found that for the former modified adsorbents the desulfurization degree can be reached to 90.6% while the latter only 81.2%.It also can be found that the Brönsted (B)acid of the adsorbent inhibited the adsorption desulfurization whereas the Lewis (L)acid,especially weak L acid,had a positive effecton adsorption desulfurization.