精馏过程多定态现象及其分析

精馏传质过程存在多定态现象 ,而产生多定态的原因有多种 .文中针对流量之间非线性转换产生的多定态 ,进行研究和分析 .当操作处于多定态区域时 ,塔内各塔板的温度与组成等参数的分布 ,以及塔顶和塔底产品浓度等参数都存在多种可能的数值 .对于一个处于多定态区域操作的工业塔 ,当某些操作参数产生波动或受外界微扰时 ,塔内各塔板的温度与组成等参数可能由正常的分布向不正常的分布突跃迁移 ,使塔的正常操作遭到破坏 .对多定态的实验结果和产生原因进行分析 ,结果表明理论上在一定条件下存在多定态的可能性 ,不同定态下的组成参数均能满足物料衡算和塔的分离能力检验     

隔板塔(DWC)多定态解的净物质流分析

与传统精馏分离工艺相比,完全热耦合精馏技术(隔板塔)有更多的操作变量(即自由度),这些操作变量在实现优化设计的同时,也会引起多定态现象。采用单组分净物质流,针对隔板塔在三组分分离过程中存在多定态解的现象进行分析,通过等效热耦合四塔模型,研究其多解现象。在不同定态解的条件下,计算并分析隔板塔内部的净物质流。结果表明,多个定态解对应的塔内部组分净物质流之间存在差异。     

间歇萃取精馏分离二氯甲烷-乙醇-水体系的模拟及实验研究

基于NRTL模型,以乙二醇为萃取剂,用Aspen Plus软件对二氯甲烷-乙醇-水三元体系间歇萃取精馏过程进行模拟,分别考虑了溶剂比、回流比、塔板数、溶剂进料位置和溶剂进料温度对整个精馏过程的影响.原料为100 kg含95％二氯甲烷(质量分数)、3％水、2％乙醇的混合溶液,利用模拟结果对各工艺参数进行分析和优化,得出了最佳的操作条件:精馏塔塔板数为20块、溶剂进料位置在第2块塔板、溶剂进料温度为38℃、回流比为2.5、溶剂比为0.575.在该操作条件下,塔顶的二氯甲烷的质量分数可达99.8％以上,回收率为96.65％,满足溶剂回收再利用的要求.通过实验对该模拟结果进行验证,得到的二氯甲烷质量分数高达99.8％,回收率为90％左右,与模拟结果基本一致.     

氯乙酸甲酯精馏工艺理论塔板数计算及设计

针对氯乙酸甲酯精馏塔塔釜液中水和氯乙酸甲酯的二元体系,采用安托因方程、Clapeyron方程、OrrickErbar法和图解法对塔板数进行了计算,得出精馏塔的理论塔板数为7块,实际塔板数34块,全塔效率0.21,并根据计算结果设计了带有"液-液分离器"的氯乙酸甲酯精馏装置,取得了很好的应用效果.     

乙腈废液渗透汽化脱水过程工艺设计

对渗透汽化脱水过程处理医药行业乙腈废液的工艺进行了研究.采用渗透汽化与精馏的耦合方式对乙腈废液脱水进行工艺设计,通过对渗透汽化和精馏工序的工艺计算,得到相关工艺参数,即当进料量为100kg/h时,渗透汽化采用单板逐级串联操作,级数为31级,膜面积为12.4m2;在精馏工序中,理论塔板数为30块,预精馏塔最佳操作点回流比为0.5,进料塔板为11层,成品精馏塔最佳操作点回流比为3.0,进料塔板12层.此时乙腈成品水份含量≤0.01%,满足工业化生产最优标准.     

环己醇精馏塔底液中环己醇回收装置的塔板数计算

针对环己醇精馏塔塔底液中环己醇和二环己基醚的二元体系,采用安托因方程、Clapeyron方程、Van Velzen-Cardozo-Langen Kamp方程和图解法等对塔板数进行了计算,得出精馏塔的理论塔板数为7块,实际塔板数23块,全塔效率0.31,并依据计算结果设计了"两段式减压精馏"环己醇回收装置.     

萃取精馏分离醋酸乙烯-甲醇的计算机模拟及工业应用

利用化工模拟软件Aspen Plus 7.3对萃取精馏分离醋酸乙烯-甲醇共沸物流程进行模拟和优化,对塔板数、回流比、进料位置、萃取剂流率和温度等操作参数进行灵敏度分析。模拟优化得到萃取精馏塔的设计参数为：塔板数31,回流比0.27,萃取剂进料位置第2块塔板,萃取剂流率21932kg/h,混合物进料位置第22块塔板,塔顶采出量18477kg/h。溶剂回收塔的设计参数为：塔板数24,回流比1.80,进料位置第19块塔板,塔顶采出量12626kg/h。在此基础上,对优化前后能耗进行对比,节省循环水、蒸汽和萃取剂用量分别为285。9万t/a、3.2万t/a和4.4万t/a,每年共带来经济效     

DMF与CHCl3混合液精馏分离工艺的研究

采用模拟的二甲基甲酰胺（DMF）与三氯甲烷（CHCl3）混合液（DMF质量分数为47％）,通过精馏塔进行分离。当进料量为2L·h^-1时,得出最佳的操作条件如下：进料状态为泡点进料,加料位置为第七块塔板进料,回流比为4。最终结果为：理论塔板数为4．5块,塔板效率为37．5％,塔顶产品DMF质量分数低于0．01％,塔底产品DMF质量分数达到96．03％。该新方法与传统的直接精馏法相比既能减少精馏能耗,又能回收利用DMF,还可使萃取剂CHCl3重复使用,对环境友好不造成污染。     

硫酸氢根吡啶催化制备乙酸正丁酯的酯化反应精馏过程模拟

采用离子液体硫酸氢根吡啶（[Hpy][HSO4]）作为催化剂,对乙酸和正丁醇在反应精馏塔中进行酯化反应生成乙酸正丁酯的过程进行模拟研究。在缺乏实验数据的情况下,使用真实溶剂似导体屏蔽模型(COSMO-RS)方法预测了离子液体与其他物质的汽液相平衡,得到了离子液体与反应体系的二元交互参数。基于共沸精馏概念设计了带有分相器的反应精馏塔,实现了离子液体的循环利用。分析了反应精馏塔总塔板数、进料模式、进料塔板位置、再沸器热值和塔板持液量对于产品质量和乙酸转化率的影响,结果表明,当反应精馏塔塔板总数为28,反应物从第4块塔板同时进料,离子液体从第2块塔板进料,且塔板持液量为0.05m3时,乙酸正丁酯纯度和乙酸转化率均可达99.9%。     

含水乙腈萃取精馏分离丙烷/丙烯的新工艺

对乙烯生产工艺中丙烷和丙烯的分离进行了研究 ,提出以含水乙腈为萃取剂的萃取精馏新工艺。选择合适的汽液平衡模型 ,利用 PRO/ II软件对原有工艺和新工艺进行模拟计算 ,计算结果表明这种新工艺具有显著的优越性。在此基础上对原有工艺和新工艺精馏塔板进行设计 ,塔板选用近年来广泛应用的新型多溢流复合斜孔塔板。新工艺对于丙烷和丙烯的精馏分离有一定的工业意义。     

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     

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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