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High‐performance HTLcs‐derived CuZnAl catalysts for hydrogen production via methanol steam reforming
Ying Tang Ye Liu Ping Zhu Qingsong Xue Li Chen Yong Lu 《American Institute of Chemical Engineers》2009,55(5):1217-1228
A series of CuZnAl oxide‐composite catalysts were prepared via decomposition of CuZnAl hydrotalcite‐like compounds (HTLcs). The catalysts derived from CuZnAl HTLcs (Cu: 37%, Zn: 15%, Al: 48% mol; using metal nitrate or acetate precursors) at 600°C provided excellent activity and stability for the methanol steam reforming. CuZnAl HTLcs were almost decomposed completely at 600°C to form highly dispersed CuO with large specific surface area while forming CuAl2O4 spinel that played a key role in separating and stabilizing the nano‐sized Cu and ZnO during the reaction. The CuZnAl catalyst prepared from metal acetates could highly convert H2O/MeOH (1.3/1, mol/mol) mixture into hydrogen with only ~0.05% CO at 250°C or ~0.005% at 210°C. It is evidenced that the former afforded stronger Cu‐ZnO interaction, which might be the intrinsic reason for the significant promotion of catalyst selectivity. © 2009 American Institute of Chemical Engineers AIChE J, 2009 相似文献
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甲醇具有结构简单、含氢量高、产能大等优点,利用甲醇与水蒸气进行重整是一种节能高效的现场制氢方式。甲醇水蒸气重整(MSR)与燃料电池联用能够实现多场景应用,但由于反应温度较高(250~300℃),存在启动速度较慢、副产CO含量较高和热效率较低等问题。低温甲醇水重整(LT-Methanol Water Reforming, LT-MWR)包括低温甲醇水蒸气重整(LT-MSR)与液相甲醇水重整(Aqueous-phase Reforming of Methanol, APRM),反应通常在200℃以下进行,同时保持较高的反应活性,进而能够减少预热时间、减弱副反应发生,且能与燃料电池实现更强的热耦合。本工作首先介绍了商用催化剂优异的性能与存在的缺陷,然后对低温甲醇水重整制氢催化剂,诸如Cu基催化剂、贵金属催化剂与光协同催化剂的研究进展进行了回顾。归纳了低温铜基催化剂的改性策略,包括合成方法、结构设计与元素掺杂。对国内外商用CuZnAlOx催化剂结构与性能的测试表明,其转化率高和稳定性好,存在的缺陷是价格较贵且在低温区催化活性急剧下降。Cu基催化剂活性受温度影响较大,在低温区活性很低,但通过适当的改性能够实现其应用价值,其改性策略包括合成方法、结构设计与元素掺杂。贵金属催化剂低温下活性较高,但存在价格昂贵、合成复杂等缺点。光协同催化剂则是在光照条件下进行催化重整,尚处于研究阶段。对于Cu基催化剂,合成方法的改进能够大大改善催化剂的微观混合程度与可重现性。适当的结构设计可提升催化剂的比表面积与热稳定性。元素掺杂则能够提升活性组分的分散度,修饰催化剂表面结构。三种改性策略能够有效提升Cu基催化剂低温下甲醇重整制氢的性能,在保持较高活性的同时,降低CO副产物的含量。展望了低温甲醇水重整制氢催化剂的发展前景和挑战,对催化剂的开发与应用有指导意义。 相似文献
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近年来,随着能源需求与日俱增,化石燃料的燃烧造成的温室效应使得地球气候变得更加恶劣,如何有效实现碳减排成为各国科学家的研究重点。将二氧化碳转化为绿色液体燃料(如甲醇)是一个重要方向。通过甲醇合成(MS)实现碳捕获,再在需要能量时进行甲醇水蒸气重整(MSR)制备氢气,实现二氧化碳的闭路循环和氢能的储存,因此MSR反应具有很高的研究价值。在众多应用于甲醇水蒸气重整的催化剂中,Cu基催化剂因其价格低廉和高活性等优点受到广泛关注。综述了Cu基催化剂在甲醇水蒸气重整中的研究进展,包括机理探索,催化剂优化及未来的发展方向,提出铜基催化剂中铜的高分散、价态调控和复合氧化物与铜的协同是性能优化的关键。 相似文献
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采用简单的改变焙烧气氛的方法改变水热法合成的CeO2纳米材料的形貌,得到的CeO2纳米材料再通过浸渍法制备CuO/CeO2催化剂,并将其应用于甲醇水蒸汽重整制氢反应。采用SEM、XRD、BET、H2-TPR、N2O滴定和XPS等对催化材料进行了表征,着重探讨了氧化铈形貌对催化剂结构、性质和性能的影响。结果表明,纳米棒状结构的CeO2负载CuO后得到的CuO/CeO2催化剂性能最佳,这主要是因为纳米棒状结构的CeO2与CuO的相互作用较强,表面存在较多的晶格缺陷和氧空穴,进而使得CuO/CeO2催化剂表相Cu含量增加,Cu物种的还原温度较低,催化活性较好。当反应温度为260 °C、水醇物质的量比为1.2、甲醇气体空速为800 h-1时,甲醇转化率可达100%,重整气中CO摩尔含量为0.16%。 相似文献
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Pan Xu Zhiming Zhou Changjun Zhao Zhenmin Cheng 《American Institute of Chemical Engineers》2014,60(10):3547-3556
Ni/CaO‐Al2O3 bifunctional catalysts with different CaO/Al2O3 mass ratios were prepared by a sol–gel method and applied to the sorption‐enhanced steam methane reforming (SESMR) process. The catalysts consisted mainly of Ni, CaO and Ca5Al6O14. The catalyst structure depended strongly on the CaO/Al2O3 mass ratio, which in turn affected the CO2 capture capacity and the catalytic performance. The catalyst with a CaO/Al2O3 mass ratio of 6 or 8 possessed the highest surface area, the smallest Ni particle size, and the most uniform distribution of Ni, CaO, and Ca5Al6O14. During 50 consecutive SESMR cycles at a steam/methane molar ratio of 2, the thermodynamic equilibrium was achieved using the catalyst with a CaO/Al2O3 mass ratio of 6, and H2 concentration profiles for all the 50 cycles almost overlapped, indicating excellent activity and stability of the catalyst. Moreover, a high CO2 capture capacity of 0.44 was maintained after 50 carbonation–calcination cycles, being almost equal to its initial capacity (0.45 ). © 2014 American Institute of Chemical Engineers AIChE J, 60: 3547–3556, 2014 相似文献
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热解油模型化合物甲醇的蒸汽转化制氢研究 总被引:1,自引:0,他引:1
研究了Ce促进的Ni基镁橄榄石催化剂上热解油模型化合物甲醇的水蒸汽转化制氢反应过程,得到活性和稳定性较好的催化剂。浸渍法制备了添加Ce的Ni基镁橄榄石催化剂,Ce的添加改善了催化剂的活性和稳定性。催化剂活性受镍铈原子比的影响,选择合适的镍铈原子比可以得到性能较好的催化剂。在750 ℃、水与甲醇物质的量比为1.5和气体体积空速11 200 h-1条件下,6%Ni-3%Ce/Olivine催化剂有最好的催化效果,此条件下,甲醇转化率达到85.72%,氢气收率为55.31%。 相似文献
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甲醇蒸汽重整制氢技术对于解决汽车、船舶等交通工具上燃料电池的氢源问题具有重要意义,近年来已成为碳氢燃料重整制氢的研究热点。本文首先综述了甲醇蒸汽重整制氢的5种反应机理,该方面的研究仍处于定性和推理阶段,尚未达成统一的结论。然后分析了甲醇蒸汽重整反应动力学的研究进展,发现大多研究是基于Cu系催化剂提出,反应温度集中在160~350℃,反应压力多为1atm,研究表明反应物水醇比最优值为1.3~1.4。最后,整理了研究中所提出的动力学模型,指出相较于单速率和三速率模型,双速率模型可反映产物中CO的含量及其对反应速率的影响,且模型相对简单,动力学方程的求解过程也相对容易,但其适用性还有待进一步验证。本文可为甲醇蒸汽重整制氢系统的设计与优化提供理论依据。 相似文献
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研究了并流共沉淀法制备的Pd/ZnO催化剂上的甲醇水蒸气重整制氢反应.考察了钯含量、还原温度、反应温度、重时空速(WHSV)和水-甲醇摩尔比(水醇比)对反应的影响.研究结果表明,当钯质量分数为15.9%,反应温度为523~573 K,还原温度为523~573 K,水醇比为1.0~1.2,WHSV=17.2 h-1时,反应具有较好的CH3OH转化率、CO2选择性、H2产率及较低的出口CO摩尔分数.与铜基催化剂相比,Pd/ZnO催化剂表现出较好的稳定性. 相似文献
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液体碳氢燃料具有能量密度高、氢含量大及便于储存和运输的特点,以其为原料经重整制氢并应用到移动式的燃料电池/加氢站对民用设备及国防武器等具有现实意义。本文首先对液体碳氢燃料蒸汽重整机理进行概述,明确当前催化剂面临的积炭、硫中毒等主要问题,从而指导高性能催化剂的设计和开发;其次,总结了几种典型液体碳氢燃料(汽油、煤油、柴油、焦油、含硫碳氢燃料等)蒸汽重整催化剂的相关进展,对比了不同催化剂在相应工艺条件下的活性及稳定性;最后,归纳了几类蒸汽重整过程强化技术包括等离子体重整、化学链重整、吸附增强重整及反应与分离耦合重整,说明了各类强化技术的优点及存在的不足,提出通过构建高效催化剂与蒸汽重整强化技术耦合有望实现液体碳氢燃料的高效转化制氢。希望本综述能为进一步研究液体碳氢燃料重整制氢提供相关指导。 相似文献
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为了强化微通道中甲醇水蒸气重整制氢,考察了催化表面活性分布对该反应过程的影响。利用计算流体力学软件FLUENT中的通用有限速率模型对微通道中甲醇水蒸气重整进行了二维数值研究。计算表明,在相同的反应条件下,通过微通道壁面上催化活性的合理分布可以提高反应器出口甲醇的转化率,这一效果在低进口温度和高速度下更为明显,在进口温度为453 K、进口速度为1.0 m/s下转化率最大提高46%。合理的活性分布应是进口处活性较低,沿着反应通道活性逐渐增加。这种催化活性分布还可降低反应通道中的冷点温差。 相似文献
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Nobuhiro Iwasa Satoshi Kudo Hiroyuki Takahashi Satoshi Masuda Nobutsune Takezawa 《Catalysis Letters》1993,19(2-3):211-216
Steam reforming of methanol, CH3OH + H2O 3H2 + CO2, was carried out over various Pd catalysts (Pd/SiO2, Pd/Al2O3, Pd/La2O3, Pd/Nb2O5, Pd/Nd2O3, Pd/ZrO2, Pd/ZnO and unsupported Pd). The reaction was greatly affected by the kind of support. The selectivity for the steam reforming was anomalously high over Pd/ZnO catalysts. 相似文献
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María A. Sánchez Vanina A. Mazzieri Javier M. Grau Juan C. Yori Carlos L. Pieck 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(9):1198-1204
BACKGROUND: The main purpose of the naphtha reforming process is to obtain high octane naphtha, aromatic compounds and hydrogen. The catalysts are bifunctional in nature, having both acid and metal sites. The metal function is supplied by metal particles (Pt with other promoters like Re, Ge, Sn, etc.) deposited on the support. The influence of the addition of Pb to Pt‐Re/Al2O3 naphtha reforming catalysts was studied in this work. The catalysts were prepared by co‐impregnation and they were characterized by means of temperature programmed reduction, thermal programmed desorption of pyridine and several test reactions such as cyclohexane dehydrogenation, cyclopentane hydrogenolysis and n‐heptane reforming. RESULTS: It was found that Pb interacts strongly with the (Pt‐Re) active phase producing decay in the metal function activity. Hydrogenolysis is more affected than dehydrogenation. Part of the Pb is deposited over the support decreasing the acidity and the strength of the most acidic sites. CONCLUSION: The n‐heptane reforming reaction shows that Pb modifies the stability and selectivity of the Pt‐Re catalysts. Small Pb additions increase the stability and greatly improve the selectivity to C7 isomers and aromatics while they decrease the formation of low value products such as methane and gases. Copyright © 2011 Society of Chemical Industry 相似文献