共查询到16条相似文献,搜索用时 125 毫秒
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通过甲醇-水蒸汽化学反应,本文提出中低温太阳热能与甲醇重整反应结合的制氢新方法,探讨了中低温太阳热能与甲醇重整制氢过程的能量转换机理,分析了不同压力条件下的水碳比、反应温度对中低温太阳热能-甲醇重整制氢的影响规律.研究结果表明:集热180~240 ℃的低品位太阳热能(品位为0.34~0.42)将能更好地与甲醇重整反应所需的品位相匹配.在反应压力为1×1.01325×105 Pa,反应产物中H2浓度可有望达到72%~75%,中低温太阳热能转化为化学能占燃料化学能的份额可达12%.该研究为低能耗制取清洁燃料氢提供了一条新途径. 相似文献
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利用浸渍方法制备的Ni/HZSM-5催化剂在生物油低温水蒸汽重整合成中表现了较高的催化活性. 探讨了催化剂的组成、重整温度、水碳比例对重整过程的影响.在电催化重整研究中,发现催化剂上通过的电流可以显著地促进生物油水蒸汽重整.通过对不同负载量的Ni/HZSM-5催化剂和Ni20/Al2O3催化剂的催化活性的比较,NiO在催化剂中负载量为20%(Ni20/ZSM)时表现出了最高的催化活性; 即使在450 oC时, 在Ni20/ZSM催化剂上也可以达到碳转化率接近完全, 氢气产率约为90%的效果. 利用XRD、ICP/AES、H2-TPR、BET等表征手段对Ni/HZSM-5催化剂的形态和结构进行了表征. 相似文献
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用电催化重整方法和NiCuZn-Al2O3催化剂进行生物油模型化合物苯甲醚的水蒸气重整制氢研究,结果表明,在700 oC和4 A条件下,获得的最高碳转化率和氢产率分别为98.3%和88.7%,电催化重整过程中发现的电流促进效应主要归结于重整反应床中温度分布的改变和电阻丝发射的热电子影响. 利用X射线衍射方法分析了反应前后的NiCuZn-Al2O3催化剂结构变化. 实验导出的苯甲醚重整反应表观活化能为99.54 kJ/mol,明显高于乙醇、乙酸和生物油轻质组分的重整反应表观活化能. 相似文献
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一种新的由共沉淀法合成的多种金属(铜、镁、铈)掺杂的镍基混合氧化物催化剂,在250~500 oC用于生物油高效重整制氢. 摩尔比为Ni:Cu:Mg:Ce:Al=5.6:1.1:1.9:1.0:9.9的催化剂表现出较高的催化重整活性,在传统的水蒸气重整模式和500 oC条件下,氢产率达82.8%;电催化重整模式中,在400 oC 和3.1 A,氢产率达91.1%.ECR模式中重整温度和通过催化剂电流促进生物油的重整和热裂解.另外催化剂在300~600 oC显示出较高的水煤气变化反应活性,生物油重整过程中催化剂性质的变化利用ICP、XRD、XPS和BET进行了表征. 生物油重整机理基于基元反应、催化剂表征进行了讨论. 相似文献
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利用La/HZSM-5催化剂,研究了催化裂解粗生物油及其模型化合物(包括甲醇、乙醇、乙酸、丙酮和苯酚)制取轻烯烃的过程. 获得的最大轻烯烃产率为0.19 kg/kg粗生物油. 研究表明,温度、重时空速和镧对HZSM-5分子筛的改性等因素可用来调制烯烃产率和选择性. 分子筛中添加镧,可适当的调节催化剂酸度和强弱酸位比例,从而提高烯烃选择性、产率和催化剂稳定性. 生物油制备轻烯烃的效率与原料的化学成分和氢碳有效比(H/Ce? )密切相关. 此外,比较了粗生物油催化裂解和热裂解过程,同时利用模型化合物研究了生物油转化为轻烯烃的相关反应历程和机理. 相似文献
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V. V. Kuznetsov O. V. Vitovsky O. A. Gasenko 《Journal of Engineering Thermophysics》2009,18(3):187-196
Regularities of methane conversion in the presence of water steam were obtained experimentally while activating chemical conversions
on the inner convex wall of an annular microchannel. The steam methane reforming was done on the Rh/Al2O3 nanocatalyst with the heat applied through the microchannel gap from the outer wall. Concentrations of the products of chemical
reactions in the outlet gas mixture are measured at different temperatures of the outer microchannel wall. The range of channel
wall temperatures at which the ratio of hydrogen and carbon oxide in the outlet mixture grows substantially is determined.
Data on the composition of methane conversion products for the ratio H2O/CH4 = 1.77 and the activation energy of methane steam reforming at reactor outer wall temperatures of up to 880°C are obtained.
The effect of the radiation heat exchange and the external diffuse limitation on the rate of chemical conversions in methane
steam reforming in an annular microchannel with external heat supply is determined. 相似文献
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Steam methane reforming is a very important chemical process in hydrogen production and solid oxide fuel cells (SOFCs). Cobalt (Co) is an important catalyst for dry and steam methane reforming. However, previous studies have confirmed that metal Co surfaces only have weak adsorption activity for H2O, which is evidently unfavorable for steam reforming. In this work we used first-principles simulations to study the activity of MnO–Co catalysts for the adsorption of H2O. Compared with the Co (111) surface and pristine Co clusters, the MnO–Co catalytic layer has a stronger adsorption capability for H2O because of the introduction of the MnO substrate, which is crucial for improving the steam reforming reaction and inhibiting carbon disposition in SOFCs. The cooperation mechanism between MnO and Co is discussed based on the analysis of electronic structures. The conclusions from this work are universal for other metal-oxide composite catalyst layers. 相似文献
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In order to produce a hydrogen stream for fuel cell utilization, the study of the ethanol steam reforming process over an
alumina supported palladium commercial catalyst was carried out. The effect of the reaction temperature, the H2O/C2H6O molar ratios and the contact time on catalytic activity and stability was studied. It was found that even at very low temperature
values complete ethanol conversion was possible. Hydrogen selectivities up to 98% were obtained at temperature values close
to 625 °C. It was also observed that for different reactant molar ratios carbon monoxide concentration exhibits a minimum
at a temperature value close to 450 °C. Furthermore, carbon formation was found to be negligible even for H2O/C2H6O molar ratios equal to the stoichiometric one.
Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15–21, 2002 相似文献