乙烯精馏塔控制中降液管时滞效应影响分析

在精馏塔动态建模中忽略了降液管容积对液相流动及传质的滞后,导致模型与实际精馏塔存在明显差异。针对某实际乙烯精馏塔,通过机理分析建模,建立理论降液管模型,并在原精馏塔模型基础上构建了考虑降液管时滞效应的乙烯精馏塔动态模型。通过仿真,将该模型与原模型的动态特性进行比较,其差异性说明考虑降液管能够更加准确地把握精馏过程的动态特性。另外,对两种动态模型分别设计控制器,整定得到的控制器参数差别很大,说明忽略降液管的影响造成在此基础上设计的控制器可能不适用于实际装置。因此,在动态建模中考虑降液管能够更加准确地对精馏塔进行分析、控制和优化,具有一定的现实意义。     

乙烯精馏塔控制中降液管时滞效应影响分析

在精馏塔动态建模中忽略了降液管容积对液相流动及传质的滞后,导致模型与实际精馏塔存在明显差异。针对某实际乙烯精馏塔,通过机理分析建模,建立理论降液管模型,并在原精馏塔模型基础上构建了考虑降液管时滞效应的乙烯精馏塔动态模型。通过仿真,将该模型与原模型的动态特性进行比较,其差异性说明考虑降液管能够更加准确地把握精馏过程的动态特性。另外,对两种动态模型分别设计控制器,整定得到的控制器参数差别很大,说明忽略降液管的影响造成在此基础上设计的控制器可能不适用于实际装置。因此,在动态建模中考虑降液管能够更加准确地对精馏塔进行分析、控制和优化,具有一定的现实意义。     

正丁醇-水混合物双塔精馏流程的稳态模拟及优化

本文采用UNIFAC模型计算正丁醇-水混合物的汽液平衡数据,应用SRK状态方程计算气、液相的焓值,对正丁醇-水混合物双塔精馏流程进行了稳态模拟和优化,得到了各物料流的温度、压强、流量和组成以及精馏塔理论板上的温度分布、汽(液)相流量分布和组成分布及再沸器的热负荷,该计算对正丁醇-水系统双塔精馏工艺的设计和操作具有实际意义。     

异类多模型动态融合软测量方法研究与应用

提出一种基于动态Gauss-Markov估计的多模型融合软测量建模方法。分别使用静态模型RBF网络、动态模型OELM和OLS-SVM进行建模,再用动态Gauss-Markov估计进行融合。该方法的精度要高于任何一个子模型,且能够跟踪时变系统的动态特性。将此方法应用于乙烯精馏塔塔釜乙烯浓度预测,结果表明该方法比其它方法具有更好的泛化效果和预报精度,显示出其良好的应用潜力。     

乙醇-苯混合物变压精馏的稳态模拟及优化

本文采用UNIFAC模型计算乙醇-苯混合物的汽液平衡数据,应用SRK状态方程计算汽、液相的焓值,对乙醇-苯混合物变压精馏(PSD-Pressure Swing Distillation)流程进行了稳态模拟和优化,得到了各物料流的温度、压强、流量和组成以及精馏塔理论板上的温度分布、液相流量分布和组成分布以及冷凝器和再沸器的热负荷。     

多项式正交配置建立精馏塔简化动态模型

根据多项式正交配置原理,系统地给出了一种通用的精馏塔简化动态模型.其建模基本原理是将精馏塔的状态变量考虑成塔的轴向距离的连续可微函数,并用多项式近似描述,使得逐板机理模型大为简化,在简化动态模型中,综合考虑了物料及能量平衡、塔板水力学及再沸器动态特性,避免了汽液平衡的迭代计算,节省了计算时间.通过对脱乙烷精馏塔进行仿真,证明了该简化模型可以给出满意的计算精度.     

溶气气浮池气液两相流二维数值模拟

采用计算流体力学软件FLUENT对溶气气浮池进行了二维数值模拟,分别对液相单相流动和气液两相流动进行了研究。模拟采用了RNG k-ε湍流模型,气液两相流的模拟采用了欧拉模型。计算得到了溶气气浮池内液相流场情况和气相在溶气气浮池内的体积分数分布,模拟结果与实验结果符合。     

基于OpenFOAM的精馏塔内气液两相流传热传质模拟

对于精馏塔内的多相传质过程,计算流体力学(Computational Fluid Dynamics, CFD)不仅可用于模拟流动现象,而且可以用于研究传热传质过程及其与流动的相互作用规律。基于之前精馏塔板气液流动模拟的研究工作,本研究应用OpenFOAM平台的多相流求解器,考虑了能量方程与组分输运方程,构建了精馏体系的传热传质模型,分别对环己烷-正庚烷理想体系与乙醇-水非理想体系进行了模拟,并分析了塔板上气液两相流动、组分浓度及温度等参数的分布规律。对于理想体系,理想溶液传质模型能够较准确地预测多层塔板上的温度及浓度场;对于非理想体系,需要在理想溶液传质模型的基础上引入活度系数模型,为此对比了UNIQUAC与NRTL两种活度系数模型的效果。在当前模拟框架下,引入活度系数模型有助于提升非理想体系温度场与浓度场的模拟精度,两种活度系数模型预测的整体趋势与文献结果基本一致,但在数值上UNIQUAC模型与文献结果吻合更好。此外,气液两相流场与浓度场分布的对比分析表明,液相的循环流动能够提升塔板的局部传质效率,导致液相入口与塔板堰处的效率高于塔板中心,但是循环区域内气液两相无法及时更新,将导致塔...     

氢、氮及轻烃混合物热焓的计算

在进行轻烃系统(主要是烯烃生产及天然气液化工业)的生产流程及设备设计工作中,需要H_2、N_2及轻烃的气液相平衡数据及焓热数据,据以进行冷凝、汽化、节流、以及蒸馏、吸收等化工过程的计算。关于气液平衡的计算方法,国内有关单位已陆续发表了一些资料及综述性文章对平衡常数作了较为全面的评述。本文试图对H_2、N_2及轻烃混合物的热焓计算作一简单的评述和介绍。     

复杂精馏塔的设计型算法

本文建立了用于复杂精馏塔(可有多股进料、汽、液相侧线出料和中间换热器的塔)的设计型算法.本算法可根据指定的独立变量值,通过优化计算确定能满足各项设计指标的一组优化设计参数值.本算法应用SHBWR(BWRS)及PR汽-液平衡和焓模型对金山乙烯装置中的典型塔等进行了考核,取得满意的结果.     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.