超临界水中花生壳气化制氢催化剂的筛选与研究

在釜式反应装置上,以原生生物质花生壳为原料、CMC为添加剂,对不同种类的催化剂在超临界水中生物质催化气化制氢的影响进行了实验研究.温度水平选择为400℃,压力控制在22～24 Mea范围内,物料的质量分数为10%,催化剂包括ZnCl2、K2CO3、KOH、Na2CO3、NaOH、LiOH、Ca(OH)2、Raney-Ni、橄榄石和白云石.实验结果表明:各种催化剂的催化效果有很大的区别,骨架催化剂Raney-Ni的大比表面积和特殊的电子层结构,使得生物质在超临界水中较低温度条件下可以达到良好的气化效果,在所考察的几种类型催化剂中,Raney-Ni的产氢效率最高,达到28.03 g/kg,是一种极具潜力的超临界水生物质制氢催化剂.     

原位捕集CO2条件下的木粉热解气化实验研究

生物质制氢研究是可再生能源的重要方向之一,但生物质气化过程中产生的CO2导致燃气中氢气含量降低.本文在一种整体式新型生物质气化催化反应器上,进行了木粉热解气化CaO原位捕集CO2的实验研究,结果表明：在最佳热解条件下产生的燃气中H2,CO,CO2体积百分数为：26.89%,27.00%,10.34%.XRD分析表明加入的CaO有明显的原位捕集CO2作用,CaO对CO2的捕集率可高达47.5%.此外,加入的CaO对木粉气化过程中产生的焦油有部分催化裂解作用,主要为芳香或多环芳香化合物.     

煤与生物质共超临界水催化气化制氢的实验研究

在压力为20～25MPa、停留时间为15～30s、：NaOH添加量(质量分数)为0．1％、反应器外壁温度为650℃的条件下，对煤与生物质的模型化合物羧甲基纤维素钠(CMC)在超临界水环境中的催化气化制氢性能进行了研究，探讨了物料浓度、压力以及停留时间对煤与CMC共气化制氢的影响．实验结果表明：煤与CMC二共超临界水催化气化制氢的主要气体产物是H2、CO2和CH4，H2的体积分数可高达60％以上；增加物料浓度、升高压力有利于提高产氢率，但延长停留时间不利于氢气的制取．     

污泥微波热解过程中CaO,ZnCl_2和水蒸气对富氢气体生成特性的影响

在单模微波反应炉中进行了污泥高温微波裂解试验,考察了CaO,ZnCl2和水蒸气对H2,CH4,CO2和CO污泥热解气组分的影响规律及影响机理.研究结果表明,在800~950℃高温条件下,引入CaO或者ZnCl2均能促进热解气中H2体积分数的提升.当CaO和DS(干基污泥)质量比从0增至1∶4时,H2的体积分数从34%提升至39.5%,然而,进一步提高CaO和DS的质量比对H2体积分数的影响并不显著.ZnCl2的效果较CaO更为显著,当ZnCl2和DS质量比从0增至1∶2时,H2的体积分数从34%提升至47.5%.高温微波热解过程中引入水蒸气有利于富氢气体的生成,在800~950℃条件下,引入0.69g/min的水蒸气时,H2体积分数达到50%,提高了49.2%.研究还表明,CaO或ZnCl2与水蒸气进行联合催化气化时,在促进富氢气体生成方面优于催化剂或水蒸气单独作用下的效果.     

甘氨酸燃烧法制备Co/CeO_2催化剂用于CO选择性氧化脱除

采用甘氨酸燃烧法制备了不同负载量的Co/CeO_2催化剂,考察了钴负载量和反应温度对其在富氢气氛中选择性催化氧化CO的反应性能,并与浸渍法制备的Co/CeO_2催化剂进行了对比;同时采用XRD、SEM和H_2-TPR等手段对催化剂进行了表征.结果表明,在富氢气氛下,甘氨酸燃烧法制备的Co/CeO_2催化剂,对CO的选择性催化氧化反应,具有较好的低温反应活性和较高的选择性.当钴金属氧化物负载量为30%时,在150~200℃,催化剂对CO的催化氧化率达到99%以上;并且在反应温度为150℃时,催化剂对CO催化氧化的选择性达到100%.另外,通过用XRD、Raman和TPR对催化剂进行分析表征,在甘氨酸燃烧法制备的催化剂中Co_3O_4具有较好的分散度,Co和Ce之间的相互协同作用提高了催化剂的催化氧化活性和选择性.     

生物质催化气化重整制取富氢气体的实验研究

以流化床为气化反应器,以固定床为重整反应器,进行了生物质气化与重整制取富氢气体的实验研究.在不同的气化温度条件下,探讨Ni基催化剂、Ca基催化剂和两者的机械混合型催化剂对制取富氢气体的影响.实验结果表明:随着气化反应器温度的提高,3种催化剂均促进了重质烃类的分解转化,而Ni基和混合型催化剂使轻质烃的催化转化能力得到提升;在750---950 ℃范围内,混合型催化剂具有最佳的催化效果,H2产率达到79.4 g/kg,产物气中的H2体积分数为53.6%～59.7%;分别添加Ni基和Ca基催化剂时,H2产率分别达到64.0 g/kg和57.9 g/kg,产物气中的H2体积分数均达到40.3%以上.     

K2O对Pt/γ-Al2O3上CO选择性氧化反应的助催效应

采用等体积浸渍法制备Pt/γ-Al2O3催化剂,通过添加K2O考察其对改善富氢气氛中CO选择性氧化性能的影响.结果表明,当加入K2O的质量分数为0.034,且采取在负载Pt后再添加的方式时,可显著改善催化剂的低温活性,在120 °C时CO转化率可达90%.降低富氢气中CO浓度有助于提高CO转化率.O2/CO增加也可提高CO转化率,但O2/CO的增加并不能提高CO氧化的选择性.为了同时得到CO高转化率和CO氧化高选择性,O2/CO(V∶V)为1.0～1.8.用BET、XRD和CO-TPD等表征方法说明了K2O的助催效应.     

碱金属对生物质化学链气化过程的影响

在固定床上研究了碱金属对稻杆水蒸气气化和化学链气化过程的双重影响规律.实验发现:700℃下碱金属盐浸渍处理后生物质水蒸气气化产气率显著提高,H_2体积分数提高到56%~57%,而CO降低到13%左右,表明碱金属极大促进了焦的重整反应和水煤气反应,且原料中固有有机钾元素作用大于添加的无机钾;提高气化温度到900℃后,碱金属催化含氧官能团的二次裂解提高了CO产率,但催化水煤气反应同时消耗CO,两者相互竞争造成CO的产气呈现非线性特性.在5%碳酸钾浸渍浓度附近获得最高的CO、H_2综合含量和最高气化效率;相比于传统生物质水蒸气气化,添加载氧体后H_2产率得到了提升,钾修饰后的载氧体可明显提高H_2含量和产气率,750℃时H_2产气率都达到最大值0.82 m~3/kg,且气化效率达到75%;提高温度虽然增加了CO产率但H_2产率反而下降,分析认为钾修饰后的载氧体在高温下易于形成熔融硅酸钾盐,在阻塞载氧体表面的同时抑制焦和水蒸气反应.     

农业生物质在超临界水中气化制氢的实验研究

以农业生物质(包括玉米秸秆、玉米芯、麦秸、稻草、稻壳、花生壳、高粱秆)为原料，羧甲基纤维素钠为添加剂，利用连续管流反应器，在反应器壁温为650℃、压力为25MPa的条件下进行了生物质气化制氢实验研究．讨论了运行时间、生物质类型、颗粒大小、反应器壁面状况等因素对气化结果的影响．实验结果表明：农业生物质在超临界水中气化生成以氢气、二氧化碳、一氧化碳、甲烷以及少量的乙烷和乙烯为主要成分的气体；气化周期内大约经过100min气体产物组成以及产量趋于稳定；在相同的实验条件下不同生物质气化得到了相似的气体组分，气体产物中一氧化碳体积分数大约为1％，甲烷体积分数超过10％，氢气的体积分数最高可以达41．28％；小颗粒的生物质气化能生成更多的氢气；反应器壁面对生物质气化有明显的催化作用．     

改性白云石在生物质制氢中的催化作用

文章对改性白云石作为催化剂进行了研究,考察了白云石、镍/改性白云石催化剂、镍/介孔改性白云石催化剂对氢气和H2 CO在产物气中的含量及氢气产率的影响。并以氢气产率为评价指标对三种催化剂的寿命进行了比较。试验结果表明无论在催化活性、强度和寿命方面镍/改性白云石和镍/介孔改性白云石相对于白云石都得到了很大的提高。镍/改性白云石和镍/介孔改性白云石是生物质催化气化制氢较好的催化剂。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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