973 resultados para Zeolite ZSM-5
Resumo:
一种小晶粒含锆ZSM-5分子筛催化剂的百分重量组成为SiO2:Al2O3:NaO2:锆=70-95:1-4:1-2:0.05-3,平均晶粒度为0.2-0.5μm总酸量为0.8-1.1毫摩尔/克分子筛,其平均晶粒度为0.2-0.5μm。本发明具有由合成气经甲醇/二甲醚制汽油反应中,甲醇/二甲醚转化率100%,汽油馏分(C5↑[+])选择性高,且产物油品烯烃含量<10%,更具有环保性,且催化剂抗积碳性能强,单程寿命可达1000小时以上的。
Resumo:
一种快速合成含锆原子ZSM-5分子筛的方法是将硅源、钠盐和去离子水配制成A溶液;将铝源、酸和去离子水按摩尔比为配制成B溶液;将锆源、去离子水配制成C溶液,在剧烈搅拌下,将B溶液滴加到A溶液中,然后加入有机模板剂,再加入溶液C,搅拌使其混合均匀,老化、晶化、固液分离,对滤饼干燥、焙烧2得到分子筛原粉。本发明具有合成出含锆原子ZSM-5分子筛的结晶度(90%>)。合成周期短,晶化时间少的优点。
Resumo:
一种快速合成强酸型ZSM-5分子筛的方法是按一定比例将硅源与模板剂、去离子水总量的一半配置成A溶液,铝源、无机酸与另一半去离子水配置成均匀的B溶液,将B溶液滴加至A溶液中,制成导向剂;再按一定比例将硅源与模板剂、去离子水总量的一半配置成C溶液,铝源、无机酸与另一半去离子水配置成D溶液,D溶液滴加入C溶液,最后再加入占总体积5-10%的导向剂,得到强酸型ZSM-5分子筛;本发明具有合成时间短,酸性强的优点。
Resumo:
一种导向剂快读合成小晶粒ZSM-5分子筛的方法,主要包括导向剂制备、分子筛合成两步。第一步导向剂制备首先根据配料比将硅源与无离子水制成A溶液后将模板剂加入,在搅拌下再将由无机酸碱调节适当碱度的铝源滴入均匀反应,按趁虚升温完成后,将合成液体中接近透明的部分分离出即为导向剂。分子筛的合成过程同导向剂相同,只是将原料配比中的有机胺模板剂由导向剂取代,晶化过程需65-75小时即可完成,得到平均粒径0.1μm的ZSM5分子筛。本发明制备简单,合成周期短。
Resumo:
ZSM-5 zeolites were synthesized in situ onto cordierite honeycombs by vapor phase transport (VPT) for the first time. The as-synthesized ZSM-5/cordierite honeycombs were impregnated with IrCl3 and tested for NOx reduction with a simulated exhaust gas as the reducing agent. Under the conditions of excess oxygen, the Ir/ZSM-S/cordierite monolith catalyst exhibited NO reduction of 73% at a temperature of 573 K and a space velocity of 20,000 h(-1).
Resumo:
Selective reduction of NO by CH4 on an In-Fe2O3/H-ZSM-5 catalyst was investigated in the presence of excess oxygen. Compared with In/H-ZSM-5, the In-Fe2O3/H-ZSM-5 catalyst with high Fe2O3 contents showed higher activity in a wide range of reaction temperatures. It was found that the addition of Fe2O3 yielded a promotion effect on CH4 activation. The influence of water vapor on NO conversion was also investigated. The activity of the In/H-ZSM-5 catalyst has been found to be strongly inhibited by water vapor, while the In-Fe2O3/H-ZSM-5 catalyst remained fairly active in the presence of 3.3% steam. (C) 2000 Elsevier Science B.V. All rights reserved.
Resumo:
The catalytic performance of Ir-based catalysts was investigated for the reduction of NO under lean-burn conditions over binderless Ir/ZSM-5 monoliths, which were prepared by a vapor phase transport (VPT) technique. The catalytic activity was found to be dependent not only on the Ir content, but also on the ZSM-5 loading of the monolith. With the decreasing of the Ir content or the increasing of the ZSM-5 loading of the monolith, NO conversion increased. When the ZSM-5 loading on the cordierite monolith was raised up to ca. 11% and the metal Ir content was about 5 g/l, the NO conversion reached its maximum value of 73% at 533 K and SV of 20 000 h(-1). Furthermore, both the presence of 10% water vapor in the feed gas and the variation of space velocity of the reaction gases have little effect on the NO conversion. A comparative test between Ir/ZSM-5 and Cu/ZSM-5, as well as the variation of the feed gas compositions, revealed that Ir/ZSM-5 is very active for the reduction of NO by CO under lean conditions, although it is a poor catalyst for the C3H8-SCR process. This unique property of Ir/ZSM-5 makes it superior to the traditional three-way catalyst (TWC) for NO reduction under lean conditions. (C) 2001 Elsevier Science B.V. All rights reserved.