气流床气化炉气化过程的分区模拟

基于气流床气化炉的三区及短路混合模型,将气化炉炉内空间按流场-化学反应特征划分为燃烧区、射流区二次反应区、回流区二次反应区和管流区二次反应区。对一次均相反应采用Gibbs平衡模型,二次均相反应、非均相反应采用动力学模型进行了模拟计算,得到了气化炉中各分区的温度和气体组成,并将其结果与Gibbs平衡模型的计算结果进行了对比,吻合良好;在气化炉适宜的操作温度范围内,采用该模型预测了最优的氧煤比和蒸汽煤比的调节范围。     

脱油沥青气化炉内气化反应数值模拟

对以脱油沥青(DOA)为原料的气流床气化炉内多相反应流动进行了数值模拟,考察了氧油质量比、蒸汽加入量和气化压力对气化性能的影响.结果表明:随氧油质量比[m(o2)/m(DOA)]增大,气化炉内温度逐渐升高;当m(o2)/m(DOA)=0.93时,有效气含率达到最大值0.837.随蒸汽量增大,气化炉出口气体温度降低,而有...     

煤新型气化技术的温度场研究

以煤和石英砂为原料。采用多热源电热气化方法，实现了煤的高效洁净转化。通过对气化炉内空间温度分布、温度梯度的研究，掌握了气化炉内温度场的变化规律。研究结果表明，煤气化过程中集气罩最高温度为440℃，炉表最高温度为1050℃；炉内温度梯度随距炉表距离的增大而减小，靠近集气罩区域，温度梯度随高度增加而增加；集气空间离炉表近的区域各点温度受辐射场影响较大，而离集气罩近区域各点温度受对流场影响显著。     

基于Shell煤气化工艺的干煤粉加压气流床气化炉性能研究

以Shell煤气化工艺为基础，利用干煤粉加压气流床气化过程模拟模型，对干煤粉加压气流床气化工艺的性能进行了数学模拟和性能研究．分析了煤气化过程中氧气和蒸汽对气化炉性能的影响，为整体煤气化联合循环(IGCC)电站系统设计中气化工艺及参数的选择提供了依据．研究表明，氧气煤比和蒸汽煤比是影响气化炉出口煤气成分、碳转化率和其他性能的主要因素，气化炉温度随着氧气煤比的增加而增加，随着蒸汽煤比的增加而下降；当蒸汽煤比一定时，随着氧气煤比的变化，冷煤气效率有一个最佳值，氧气煤比要比蒸汽煤比对气化炉性能的影响更为显著．     

基于停留时间分布的气流床气化炉通用网络模型

气流床气化炉的数学模型是气化装置设计和操作优化的基础,气固停留时间分布是影响气流床气化炉出口组成和碳转化率的关键因素。以气固停留时间分布为依据,结合反应动力学建立气流床气化炉的通用网络模型,模拟值与工业值吻合。对于神府煤,考察了氧煤比改变对气化结果的影响,结果表明:最佳氧煤比(氧气体积与煤(干基)质量之比)期望值约为0.655Nm3/kg,生产中为保证液态排渣,氧煤比应控制在0.663Nm3/kg左右。该通用网络模型计算速度快,适用于建立气化炉的动态模型。     

煤气化炉动态数学模型的建立与分析

以Texaco气化炉为研究对象,分析气化炉内流动、燃烧和气化反应特性,将Texaco气化炉膛分成3个模拟区域,即燃烧区、气化区和回流区,分别对各区运用质量守恒和能量守恒方程,得到集总参数动态数学模型。该模型考虑了气固两相流动、煤热解、辐射换热及包括均相和异相在内的气化反应过程。在模型基础上进行动态与静态仿真,并进行参数化研究和仿真结果分析,得出了一些重要参数的变化趋势和结论。模型的优点在于能对气化炉内喷动区的组分及温度分布进行更加准确的预测,从而具有较好的工程应用价值。     

水煤浆水冷壁气化炉的反应器网络模型

以中国新开发的分级给氧式水煤浆水冷壁气化炉为对象,建立了可应用于系统流程模拟的气化炉单元模型。该模型采用搭建反应器网络的方法模拟反应室内不同流动区域,然后耦合壁面两相渣层模型和水冷壁传热模型进行计算。模型计算得到的出口气化温度、合成气成分和水冷壁产汽量与工业运行数据基本吻合,炉内气体温度分布与三维数值模拟结果相近。炉内温度、壁面渣层厚度和水冷壁温度的分布结果显示出水煤浆水冷壁气化炉独特的传热特性。     

气流床煤加氢气化反应器的数值模拟及流场特性分析

该文通过对Rockwell公司开发的6t/d的气流床煤加氢气化反应器的3维数值模拟,模拟了加氢气化反应器内的流场和反应过程。模拟采用了Johnson和Tran的加氢热解动力学模型,并且考虑了焦油的加氢裂解反应。数值模拟预测结果和6t/d加氢气化反应器的实验结果符合得较好。模拟结果表明:加氢气化反应器内的流场可以分为交叉撞击区、射流-回流区和管流区3个区域。一次脱挥发分反应在煤粉和炽热氢气快速混合后的很短时间内就能完成,甲烷主要在交叉撞击区和射流-回流区生成,加氢气化反应器下部大部分区域为管流区。在交叉撞击区及射流-回流区,颗粒粒径越小则颗粒升温及失去质量越早;在管流区,颗粒粒径对颗粒的质量变化及温度历程影响不大。     

蒸汽煤比对湍动循环流化床煤气化的影响

以空气和水蒸气为气化剂,在压力为0.3 MPa的湍动循环流化床热态实验台上对淮北烟煤进行了煤气化试验,研究了蒸汽煤比(质量比)对气化过程的影响.气化炉提升段具有下宽上窄的特点,床料采用宽筛分石英砂.气化试验过程中,实现了提升段下部湍动流化、上部环核流动.试验结果表明:随着蒸汽煤比的增加,煤气中CH4体积分数基本保持不变,CO体积分数从13.12%下降到11.98%,H2体积分数从初始12.3%增加到14.63%而后下降至14.19%,CO2体积分数从13.84%下降至12.94%后,略微上升至13.06%.蒸汽煤比的变化对干煤气产率、冷煤气效率及碳转化率都有影响,其最大值分别为2.89 m3/kg, 59%, 81%.     

几种干煤粉加压气化炉结构特点

干煤粉加压气化技术具有氧、煤消耗低、冷煤气效率高、碳转化率高、污水较容易处理、能气化高灰熔点煤、煤种适应行广、很短时间内即可转化为无副产品的气体等优点。针对国外有代表性的三种干煤粉加压气化炉和德士古加压气化炉进行对分析,阐述了各炉型在结构的特点和差异,阐明了干煤粉加压气化技术炉型发展的趋势。     

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