FeCrAl丝网负载FAU沸石膜的制备及其催化性能

摘要

采用水热法制备FeCrAl丝网负载FAU沸石膜,考察了合成液老化、载体预涂晶种以及晶种液中添加聚乙烯醇(PVA)等因素的影响,评价了FeCrAl丝网负载FAU沸石膜对模型吸热燃料正辛烷裂解的催化活性.结果表明,载体表面预涂Y分子筛晶种后有助于增加载体表面分子筛负载量,采用老化后的合成液,效果更显著,并且更易在金属丝上生长出一层连续致密的FAU沸石膜.在相同水热合成条件下,载体表面用含PVA的晶种液预涂晶种后,可增加分子筛负载量.正辛烷在FeCrAl丝网负载FAU沸石膜上的初始裂解转化率(7.2％ ～ 13.2％,500℃)高于其在空白载体上的裂解转化率(4.4％),FAU沸石膜的初始催化活性不仅与载体表面分子筛负载量有关,也与分子筛膜的形貌有关.%The preparation of FAU-type zeolite films on FeCrAl grids by hydrothermal synthesis was studied with an emphasis on effects of ageing of the synthesis mixture, seeding of the support and addition of poly vinyl alcohol (PVA) in the seed solution. The catalytic activity of FAU-type zeolite films was evaluated for cracking of a model endothermic fuel (n-octane). The results show that coating of the support with Y-type zeolite seeds could increase the loading of zeolite crystals on the support and thus facilitate to grow a continuous and dense FAU-type zeolite film around the wire, especially using an aged synthesis mixture. Under the same synthesis conditions, the loading of zeolite crystals was enhanced using a PVA-containing seed solution for seeding. The initial conversion of n-octane at 500 ℃ was higher over FAU-type zeolite films (7.2% ~13.2%) than that over the bare support (4.4% ). The activity of zeolite films depends on not only the loading of zeolite crystals but also the morphology of the film.