共查询到19条相似文献,搜索用时 46 毫秒
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Pd/C催化剂的失活与再生 总被引:4,自引:1,他引:4
对用于加氢反应的Pd/C催化剂的失活原因进行了研究分析。结果表明,杂质覆盖是催化剂失活的主要原因。提出了加催化剂防护层、碱液再生催化剂等方法来延长催化剂的使用寿命。 相似文献
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以硝酸镍为镍源,分别以NH3.H2O,NH4HCO3,NH3.H2O+NH4HCO3为沉淀剂采用沉淀法制备镍/硅藻土催化剂,用于1,2-环己二醇脱氢制备邻苯二酚,考察了不同沉淀剂、焙烧温度、沉淀温度制备的催化剂对1,2-环己二醇脱氢反应性能的影响,并通过XRD,BET,CO2-TPD(热设计功耗)等方法对催化剂进行了表征。结果表明:不同的沉淀剂对镍的分散度、孔结构及表面碱量都有影响,以NH3.H2O+NH4HCO3复合沉淀剂制备的镍/硅藻土催化剂上活性组分镍晶粒度小、分散度较高,催化剂平均孔径较大,催化剂表面碱中心数目多、碱量大,表现出良好的催化活性和邻苯二酚选择性。另外,催化剂适宜沉淀温度为90℃、焙烧温度为350℃。上述适宜条件制备的催化剂在320℃下用于1,2-环己二醇脱氢制备邻苯二酚,1,2-环己二醇转化率达到99.1%,邻苯二酚选择性达到86.8%。 相似文献
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环己酮二聚体脱氢是以环己酮为原料制备邻苯基苯酚的一步重要反应。但是有多种原因会引起环己酮二聚体脱氢催化剂失活,影响其使用寿命及选择性。根据有关测试数据及实验,分析了脱氢催化剂失活的原因,并提出了改进的具体措施。 相似文献
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Deactivation of hydroprocessing catalysts 总被引:9,自引:0,他引:9
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Kaolin as a raw material for mesoporous support was firstly modified by calcination, acid treatment, and then was used to prepare nickel catalysts. The amount of alumina which was activated in kaolin during thermal treatment and then leached out in the acid was different. XRD pattern of the kaolin calcined at 600℃ or 900℃ exhibited only the diffraction peaks for amorphous silica and quartz while that calcined at 1100℃ showed obvious peaks for γ-Al2O3. Therefore, the nickel-based catalysts exhibited different physic-chemical properties. Atmospheric syngas methanation over the catalysts clarified an activity order of CA-1100 > CA-900 > CA-1400 > CA-600 > KA ≈ 0 at temperatures of 350-650℃ and a space velocity of 120 L·g-1·h-1. Metallic nickel with small diameter which has medium interaction with the modified kaolin and is well dispersed on the support would have reasonably good activity and carbon-resistance for syngas methanation. 相似文献
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B. N. Kuznetsov 《Catalysis in Industry》2009,1(3):250-259
Increasing interest in the use of resources of organic raw materials alternative to petroleum stimulates researchers to study the catalytic intensification of fossil coal and vegetable biomass conversion. The industrial use of the developed technologies is restricted by the problem of enhanced catalyst deactivation. The main reasons for catalyst deactivation in solid organic raw materials conversion are considered in the review. The possible ways of the successful solution of the problem of catalyst deactivation in the processes of coal and biomass liquefaction and gasification and wood delignification and hydrolysis are exemplified by the studies accomplished over the last decade. In the case of technologies using the synthetic catalysts, the methods of their regeneration developed for the catalytic processing of heavy petroleum residues can be applied. The catalyst regeneration is not demanded for the processes accomplished in a fluidized catalytic bed under the conditions of catalyst loss as a result of its attrition and in the case of the application of melted catalysts, cheap iron-containing catalysts, catalytically active slag materials, and natural minerals. The substitution of dissolved catalytic systems for solid catalysts allows for the diminishing of their deactivation in the processes of wood delignification and hydrolysis. 相似文献
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镍基催化剂是一种由多孔结构的镍铝合金的细小晶粒组成的固态异相催化剂。镍基催化剂因具有机械强度高、催化活性好、制备简单、价格低廉等优点,被广泛地应用到石油、化工、制药、油脂、香料、双氧水、合成纤维等方面的加氢、脱氢、脱卤、脱硫等转化反应过程中。随着催化工业的逐步发展,对催化剂性能的要求也越来越高,原始的镍基催化剂利用率低、抗酸性差等缺点限制了该催化材料的进一步应用。因此,近年来,许多研究者一直在尝试对镍基催化剂进行改性,以改善其使用寿命、催化活性、抗酸性等性能。着重介绍了镍基催化剂的强化措施以及镍基催化剂的应用,并对镍基催化剂在各类催化反应中的应用情况进行了详细概述,在此基础上展望了镍基催化剂的未来发展。 相似文献
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负载型Ni基催化剂是应用于CO甲烷化反应的重要催化剂,其金属分散度、活性位结构和化学组成是决定催化剂活性与稳定性的关键因素。综述了金属Ni活性中心结构、载体与助剂对负载型Ni基催化剂甲烷化反应活性和稳定性的影响,在提高催化剂活性的基础上,为开发低成本的负载型Ni基催化剂具有重要意义。 相似文献
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用于过氧化氢异丙苯分解反应的沸石催化剂失活与再生的研究 总被引:1,自引:0,他引:1
摘要 本文主要分析了改性 俘沸石催化剂失活的原因并考察其再生方法 。研究表明 ,钠的毒化作用可经水洗过氧化氢异丙苯 而抑制。程序升温氧化 表明改性 日沸石催化剂上的积碳量较少。色质联用分析表明,改性月沸石催化剂上的积炭物质主要是对甲乙苯、枯酚及二元梭酸醋等。这些物质是由于苯酚聚合或苯酚与副产物发生副反应而产生 的。第一次再生后的催化剂活性和单程寿命虽有一定程度的下降,但在后续再生后,催化剂活性和单程寿命基本稳定。 相似文献