共查询到20条相似文献,搜索用时 62 毫秒
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用XRD参比强度法,测定了分子本硫和萘在活性炭、硅胶和TiO2上自发分散后的残余晶相量,由图解外推法得到了硫和萘的最大分散量(阈值)。证实了这些体系存在自发单层分散的倾向,并对其原因进行了讨论。 相似文献
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简述了SAPO-11分子筛的结构和合成原理,介绍了传统水热合成方法。通过几种方法对其进行改进,比较了改进前后分子筛的结构和性能。同时归纳和总结了金属负载改性对SAPO-11分子筛应用于烷烃异构化性能的影响。 相似文献
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为回收工业废气中的磷化氢(PH3)并资源化,采用浸渍法制备了一种CaCl2改性13X分子筛吸附剂,通过容积法研究了25—70℃PH3气体在改性13X分子筛上的等温吸附行为。结果表明,在实验条件范围内25,40,55,70℃下PH3的饱和吸附量(质量分数)分别为2.528,1.901,1.591,0.925mg/g。Freundlich吸附等温方程很好地模拟了改性13X分子筛对PH3的等温吸附,Langmuir和Henry吸附等温方程对吸附平衡数据的拟合效果不佳表明了改性13X分子筛表面吸附位的不均匀分布。当初始吸附量为0.10mg/g时,等量吸附热值最大,为17.81353kJ/mol,即等量吸附热不超过18kJ/mol,过程为物理吸附,便于PH3气体的解吸。 相似文献
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ZSM-5分子筛的研究进展 总被引:1,自引:0,他引:1
介绍了ZSM-5分子筛的基本结构,比较了ZSM-5分子筛在不同条件下合成情况,阐述了ZSM-5分子筛的改性的现状,促进ZSM-5分子筛催化剂的研发工作进一步发展。 相似文献
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Zn, La, Zr, Sn and Ti loaded molecular sieves were prepared by impregnation method. Conversions of benzothiophene and dibenzothiophene over the metal oxides modified ultra stable zeolite Y(USY), ZSM-5, β and MSU-2 molecular sieve catalysts were investigated by means of micro-activity test (MAT) experiments. The results showed that Zn and La loaded catalysts were better than the other metals, and ZSM-5 with lower SiO2/Al2O3 mole ratio showed better results than those with higher SiO2/Al2O3 as far as desulfurization reaction is considered. A comparison of the desulfurization activities of the La/Zn-USY catalyst with USY catalyst indicated that the bimetal loaded USY catalyst gave good products selectivity when sulfur containing heavy oil was used as the feedstock. The sulfur content in gasoline fraction was decreased by 25%, and there was no loss in the Research Octane Number. 相似文献
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采用密度泛函理论研究金属离子(La~(3+),Ce~(3+),Y~(3+),Ga~(3+),Cr~(3+),Zn~(2+),Cu~(2+))改性Y型分子筛的水热化学。结果表明,金属离子取代Y型分子筛骨架Al的能力较弱,以M(OH)(Z-1)+形式存在的金属离子能够进入分子筛β笼,且更倾向定位于β笼Ⅰ'位,增强分子筛Al和相邻骨架O原子之间的作用力,提高分子筛的结构稳定性。探讨制备金属离子改性Y型分子筛应考虑金属离子性能和金属离子与分子筛骨架元素的作用。 相似文献
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介绍了沸石作为一种具有独特结构的催化剂在炼油与石化生产过程的应用现状与发展趋势。其中包括在催化裂化、加氢裂化与加氢精制、异构化、烷基化加工过程以及乙苯、异丙苯、直链烷基苯、己内酰胺等石化产品生产中的应用新进展。认为沸石催化剂无毒无害的特性及其相关绿色工艺适应环保发展趋势,将获得越来越广泛的应用。 相似文献
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Effects of metal modifications of Y zeolites on sulfur reduction performance in fluid catalytic cracking process 总被引:2,自引:0,他引:2
The acidity of catalytically active component, e.g., ultra stable Y zeolite (USY), plays an important role in determining their cracking activity and selectivity. To develop advanced sulfur reduction catalytic cracking catalysts, different type of elements were used to modify USY and the resulting catalysts were evaluated in a confined fluidized bed reactor and a micro-activity testing unit. The relation between the acidity of the zeolite and the conversion of sulfur compounds as well as the distributions of fluid catalytic cracking (FCC) products were discussed. The results showed that the rare earth (RE) metal can stabilize the catalyst and increase the conversion, but cannot increase the selectivity to thiophene compounds; V can reduce the sulfur content by 36.3 m%, but decreases the overall conversion compared with the base catalyst. An optimum catalyst was obtained by the combined RE and V modification, over which the sulfur content in FCC gasoline can be decreased and the selectivity for the target products can be improved, with the sulfur content reduced by 30 m% and the selectivity to coke even decreased by 0.20 m% at a comparable conversion level of the base catalyst. 相似文献
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为了改善L型沸石的催化性能,优化其在FCC中的应用,对L沸石进行离子交换和脱铝的改性研究。考察离子交换时间和离子交换方式对降低L沸石中氧化钾含量的影响及水热焙烧和化学脱铝对提高L沸石硅铝物质的量比的影响。结果表明,L型沸石离子交换时间不易过长,较适宜的时间为3 h。离子交换和水蒸汽处理相结合对降低L型沸石的钾含量更有效,离子交换和水蒸汽处理交替进行3次的样品氧化钾质量分数可降至0.82%。水热焙烧和化学脱铝能使L型沸石显著脱铝,其中,经过700 ℃水蒸汽处理1 h,再进行盐酸处理而制得改性L型沸石样品的硅铝物质的量比可达21.91,相对结晶度高于80%。 相似文献
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HY which is loaded with SbF5, BCl3, or BF3 at low coverages, one metal halide molecule per Brønsted acid site, is shown to be active in the isomerization and cracking of n-hexane and n-butane at room temperature. In contrast, NaY with the same metal halide loading shows greatly reduced activity under identical reaction conditions. The cracking reaction was repeated with DY in place of HY, demonstrating deuterium incorporation into the hexane isomer and light alkane products through interaction with the Brønsted site. Flow reactor studies demonstrate that the conversion is not constant as a function of time on stream, going through an induction period, reaching a maximum, at around 400 s, and then decaying to ~1% after 1 h. 相似文献
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选择氧化锌(Zn O)、铝掺杂氧化锌(AZO)、氧化锡锑(ATO)以及ATO包覆硫酸钡(Ba SO4)4种纳米粉体抗静电剂球磨分散得到其水相悬浮液,利用喷雾共混的方法制备改性聚丙烯腈(PAN)纺丝原液,进行湿法纺丝,研究了表面活性剂种类、研磨工艺对纳米粉体在水相中沉降性的影响,以及改性PAN纤维的抗静电性能。结果表明:采用自制的非离子/阴离子表面活性剂复配物(FCY)作为分散剂,FCY质量分数(相对于纳米粉体)为2%,研磨时间3 h,纳米粉体的水相分散效果好,分散工艺对4种纳米粉体均有很好的适用性;ATO改性PAN纤维具有较好的抗静电效果,当添加ATO质量分数为2.0%时,PAN纤维的体积比电阻为3.1×109Ω·cm,具有耐久性,可以满足抗静电织物对原料的要求。 相似文献