炭化型煤的水蒸气气化特性及动力学

以褐煤等粉煤为原料,采用冷压成型和低温炭化工艺,研制出高热稳定性的气化用炭化型煤。在固定床气化装置中,研究了炭化型煤的水蒸气气化特性和动力学。研究表明,气化温度从880℃提高到1 000℃,碳转化率达到85%的时间从40~50min缩短至20min以内;反应进行5~8min时,炭化型煤气化反应速率达到最大值;气化温度为880℃时,反应全程处在化学反应控制区;气化温度为920℃、960℃和1 000℃时,反应过程由化学控制区向内扩散控制区转移,转移的拐点在碳转化率为90%~95%之间出现。炭化型煤气化动力学可用二维扩散模式的缩核模型描述,在化学反应控制区,表观活化能为93.83~104.11kJ/mol,表观活化能与指前因子存在动力学补偿效应;在内扩散控制区,表观活化能为76.45~87.05kJ/mol。     

煤和煤焦在压力下加氢气化的动力学研究——Ⅰ.温度的影响

在固定床加压反应器和加压热天平上,对五种中国气化用煤及其煤焦进行了加氢气化的动力学研究。发现在升温过程中各类产品气体的生成速率都随温度而变化,甲烷和乙烷的生成速率在600℃左右可达到最大值。沈北、蔚县煤焦在850～1000℃,2.1 MPa下加氢反应的表观活化能分别为108和95kJ/mol。随着煤焦制备温度的提高,煤焦加氢反应的平均比气化速率和最终转化率都下降。     

高炉熔渣中煤-CO2气化反应性的实验研究

利用STA409PC综合热分析仪以等温热重法对高炉熔渣中煤焦-CO2气化反应性进行了研究,主要考察了渣煤比、气化反应温度和煤种对气化反应的影响,并用反应速率方程法对其动力学参数进行求算.实验结果表明:煤焦的碳转化率、气化反应速率与渣煤比正相关;在煤焦的气化反应中,高炉熔渣具有一定的促进作用;在1673K以下,煤焦的碳转化率、气化反应速率峰值随温度的升高而上升,而当温度高于1673K后,煤焦的碳转化率、气化反应速率峰值随温度的上升呈现下降的趋势;不同煤种,其气化反应性有很大的差异,大同煤的气化反应性要好于阜新煤和焦炭;不同条件下,煤焦的气化反应动力学参数具有很大的差异,焦炭的表观活化能和指前因子随渣煤比的增大而升高,阜新煤的表观活化能和指前因子随渣煤比的增加先降低、后升高.     

SrFeO3-x氧脱附和吸附的热重法分析

用热分析仪研究了具有钙钛矿结构的材料SrFeO3-x在200℃～900℃温度区间氧的脱附和吸附，等温氧吸附动力学的测量表明，SrFeO3-x在200℃时仍然有较快的吸附速率，饱和吸附量随温度的降低而增大，用多个升温速率法测量了SrFeO3-x的氧脱附活化能，在500℃～600℃温区，活化能约为200kJ/mol。     

煤焦-CO_2高温气化反应特性的实验研究

利用STA409PC综合热分析仪以等温法研究煤焦-CO2高温气化反应,考察了煤种、气化温度及气流速度对煤焦气化反应的影响,并对其动力学参数进行了求算.实验结果表明:当气化温度低于煤焦灰熔点温度时,煤焦的碳转化率和反应速率峰值随气化温度的升高而增大,当气化温度高于煤焦的灰熔点温度时,煤焦的碳转化率和反应速率变化十分缓慢,甚至有下降的趋势;不同煤种的气化反应动力学参数有很大的差异,鞍钢煤焦和本钢煤焦的活化能均为140kJ/mol,阜新煤焦的活化能为70kJ/mol.当煤焦的气化反应温度高于煤焦的灰熔点温度时,扩散成为煤焦气化反应的主要限制环节,提高气流速度有利于煤焦气化反应的进行.     

用差热法研究平鲁煤焦的水蒸气加压气化动力学

用自行改造组装的多气氛高压高温差热分析装置研究了平鲁煤焦的水蒸气加压气化动力学。水蒸气分压为0.01,0.03,0.11和0.33MPa,最高反应温度为1450K.实验结果表明,反应温度对气化速率有显著影响;水蒸气分压对气化速率在低压时有明显影响;气化反应的活化能随转化率变化。与实验值基本吻合的计算值表明虑及压力和孔结构变化的动力学方程可以较好地描述平鲁煤焦在加压水蒸气中的气化行为。整个工作还表明,DTA技术也是研究煤气化动力学的一种有效手段。     

稻草快速热解半焦的CO_2气化动力学

利用热重分析仪研究了快速热解温度为400,500,600℃时得到的稻草半焦的CO2气化动力学。研究了温度为850,900,950,1 000℃时半焦的CO2气化过程。结果表明,随着稻草热解温度的提高,半焦的气化反应速率呈下降趋势。利用随机孔模型进行了模拟,并计算出了其动力学参数。结果表明,随机孔模型能较好地反映快速热解稻草半焦气化反应速率达到最大值后再下降的现象,与实验结果相吻合,半焦的活化能随着快速热解温度的升高而升高。     

升温速率对煤焦-CO_2高温气化反应性的影响

利用STA409PC综合热分析仪以程序升温法来研究煤焦-CO2气化反应,主要考察了高温下升温速率对煤焦气化反应性的影响,并用Ozawa法和单一升温速率法对其动力学参数进行了求算.实验结果表明:升温速率对煤焦气化反应有明显影响,升温速率越大,相同时间内,煤焦的碳转化率越高,但是其升温速率存在一上限值,而且这一上限值随煤种的不同而不同;随升温速率的增大,DTG曲线向高温方向移动,峰值温度和最大反应速率也随之增大;利用Ozawa法求得的鞍钢煤焦和本钢煤焦的活化能均在110 kJ/mol左右,阜新煤焦的活化能为87 kJ/mol.     

玉米芯热重分析及气化反应动力学研究

利用热重分析实验得出玉米芯气化可大致分为3个阶段：水分蒸发、挥发分析出和焦炭阶段．研究表明,当升温速率为20℃／min时,物料的最大失重率只有85．75％,在所有的升温速率中最小;当升温速率为10℃／min时,物料的最大失重率可达到97．94％．以升温速率为5℃／min的热重曲线研究玉米芯气化过程中的挥发分析状况,当温度在250℃-330℃时,气化反应属于2级反应,其拟合方程Y=-2332．3x-7．9534,活化能E和指前因子A分别为19．4kJ／mol和3．4×10^4min;温度在330℃～530℃时,气化反应属于1级反应,其拟合方程Y=-1960．5x-9．7076,活化能E和指前因子A分别为16．3kJ／mol和5．0×10^1min^-1．     

煤焦加压Boudouard反应动力学

将3种不同变质程度煤于1173K下制成煤焦,在PBBR装置上于1073～1223K温度和0.29～2.47MPa下进行煤焦Boudouard反应试验。提高反应温度和压力均能使煤焦的基碳转化率和平均比气化速率增大,且显示温度的影响大于压力。随着原煤变质程度加深,其煤焦的气化活性减小。未反应芯表面反应模型能较好描述此气化过程,并可计算出反应动力学参数。活化能,频率因子和反应级数。用Na_2CO_3和K_2CO_3作催化剂能明显加速官地煤焦与CO_2气化反应速率,并显著降低其反应活化能,且K_2CO_3的催化效果大于Na_2CO_3。     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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