研究了甲醇制丙烯(MTP)催化剂经过多周期反应后失活的本质原因,据此提出了一种简便易行的催化剂再生方法,即二次晶化法,并将其应用到失活MTP催化剂的再生中。采用X射线衍射(XRD)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)、N_2吸附、^...研究了甲醇制丙烯(MTP)催化剂经过多周期反应后失活的本质原因,据此提出了一种简便易行的催化剂再生方法,即二次晶化法,并将其应用到失活MTP催化剂的再生中。采用X射线衍射(XRD)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)、N_2吸附、^(27)Al魔角旋转固体核磁共振(^(27)Al MAS NMR)、NH_3程序升温脱附(NH_3-TPD)、吡啶吸附红外(Py-IR)光谱等测试技术对再生前后HZSM-5分子筛催化剂的晶体结构、硅铝比、织构性质、酸性质等进行了表征。并在常压(甲醇分压为30 k Pa)、反应温度为470°C、甲醇质量空速(WHSV)为1 h^(-1)的条件下,研究了再生前后HZSM-5分子筛催化剂的催化性能。结果表明,分子筛晶体结构被破坏、活性位流失是多周期反应后HZSM-5分子筛催化剂活性下降的主要原因。经过二次晶化再生后,催化剂的相对结晶度、比表面积、孔容和酸量都明显提高,晶体结构和活性位得到了有效修复,再生催化剂在MTP反应中重新表现出优异的甲醇转化能力和丙烯选择性。展开更多
Zeolites Y of FAU type containing different transition metal hetero-atoms(MY or M1M2Y,where M = Ti,Co,Ni,Mo,Zr,etc) in the framework were synthesized.The effect of different hetero-atoms on the crystallinity of zeolit...Zeolites Y of FAU type containing different transition metal hetero-atoms(MY or M1M2Y,where M = Ti,Co,Ni,Mo,Zr,etc) in the framework were synthesized.The effect of different hetero-atoms on the crystallinity of zeolite Y was characterized by XRD and SEM.The zeolites MY or M1M2Y exhibit the same phase profiles as zeolite Y by XRD.SEM results showed that MY zeolite is provided with well-defined crystal and larger crystal size.Zeolite Y containing single transition metal hetero-atom(MY) exhibits lower crystallinity than zeolite Y.However,the zeolite Y containing two suitable hetero-atoms(M1M2Y) has a much higher crystallinity than MY due to the collaboration of M1 and M2;there is an optimum composition for two hetero-atoms to get a high crystallinity.展开更多
文摘研究了甲醇制丙烯(MTP)催化剂经过多周期反应后失活的本质原因,据此提出了一种简便易行的催化剂再生方法,即二次晶化法,并将其应用到失活MTP催化剂的再生中。采用X射线衍射(XRD)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)、N_2吸附、^(27)Al魔角旋转固体核磁共振(^(27)Al MAS NMR)、NH_3程序升温脱附(NH_3-TPD)、吡啶吸附红外(Py-IR)光谱等测试技术对再生前后HZSM-5分子筛催化剂的晶体结构、硅铝比、织构性质、酸性质等进行了表征。并在常压(甲醇分压为30 k Pa)、反应温度为470°C、甲醇质量空速(WHSV)为1 h^(-1)的条件下,研究了再生前后HZSM-5分子筛催化剂的催化性能。结果表明,分子筛晶体结构被破坏、活性位流失是多周期反应后HZSM-5分子筛催化剂活性下降的主要原因。经过二次晶化再生后,催化剂的相对结晶度、比表面积、孔容和酸量都明显提高,晶体结构和活性位得到了有效修复,再生催化剂在MTP反应中重新表现出优异的甲醇转化能力和丙烯选择性。
文摘Zeolites Y of FAU type containing different transition metal hetero-atoms(MY or M1M2Y,where M = Ti,Co,Ni,Mo,Zr,etc) in the framework were synthesized.The effect of different hetero-atoms on the crystallinity of zeolite Y was characterized by XRD and SEM.The zeolites MY or M1M2Y exhibit the same phase profiles as zeolite Y by XRD.SEM results showed that MY zeolite is provided with well-defined crystal and larger crystal size.Zeolite Y containing single transition metal hetero-atom(MY) exhibits lower crystallinity than zeolite Y.However,the zeolite Y containing two suitable hetero-atoms(M1M2Y) has a much higher crystallinity than MY due to the collaboration of M1 and M2;there is an optimum composition for two hetero-atoms to get a high crystallinity.
