摘要
以HZSM-5为原料,在不同焙烧条件下处理了HZSM-5分子筛,并采用X射线衍射、X射线荧光光谱、吡啶吸附红外光谱、NH3-程序升温热脱附等方法对其进行表征,考察了焙烧条件对HZSM-5分子筛对称性、结晶度和酸性的影响。结果表明,高温水蒸气焙烧可加速分子筛晶体对称性的转变,分子筛从正交晶系Pnma空间群转变为单斜晶系P21空间群。高温水蒸气焙烧导致分子筛B酸中心和强酸中心的大量损失,随着水蒸气焙烧温度升高,分子筛酸中心尤其B酸中心的损失更为明显。
HZSM - 5 catalysts were synthesized with HZSM -5 zeolite as raw materials at different calcination condition, and the effect of calcinations conditions on their crystal symmetrical property, crystallinity and acid traits were characterized by x - ray diffraction, pyridine - infrared spectroscopy and NH3 temperature programmed desporption method. The results showed that calcination at high temperature with steam could accelerate the transition of crystal symmetry from orthorhombic space group Pmax to monoclinic space group P21. Calcination at high temperature with steam led to the substantial loss of B acid sites and strong acid sites, and the loss of acid sites, especially B acid sites, increased with temperature.
出处
《石化技术与应用》
CAS
2010年第4期289-292,共4页
Petrochemical Technology & Application
