基于CAPE-OPEN标准的萃取精馏过程模拟研究

萃取精馏过程模拟计算对工业生产具有重要指导作用,为进行基于CAPE-OPEN标准的萃取精馏过程模拟研究,首先了解其处理体系的特点,确定萃取精馏塔功能建立其数学模型,采用内外层算法进行求解计算;然后,使用VisualC++与COM组件思想对模块进行开发;最后,采用苯-环己烷和四氢呋喃-水两个体系进行测试。将主要工艺参数同Aspen Plus化工模拟软件的计算结果对比,结果表明萃取精馏塔各平衡级的组成、流量和温度分布等参数结果准确可靠,满足分离指标,证明了该单元模块可用于萃取精馏过程模拟研究。     

浓度对传质系数的影响及多元物系传质

在筛板塔中对甲醇-乙醇-水三元物系进行精馏传质过程实验,考虑浓度对传质系数的影响建立了一个数学模型,对各组分在塔中的浓度分布进行模拟计算,计算结果能正确反映各组分在塔中浓度分布的变化规律.实验与计算结果都表明在某些浓度范围内乙醇呈现出比较复杂的变化规律.     

精馏过程稳态模拟计算方法的研究进展

精馏过程稳态模拟主要是针对实际精馏操作过程中精馏塔内的温度、压力、汽液相流量及汽液相组成分布进行分析,并通过模拟找到制约生产的瓶颈。稳态精馏过程模拟计算的难点是求解MESH方程组。国内外已经提出了许多稳态精馏过程模拟的计算方法,主要包括三对角矩阵法、牛顿法、内外层法、松弛法以及其他方法。精馏过程的数学模型及其求解方法直接影响到精馏过程模拟结果的准确性。随着计算机的发展,许多精馏过程的稳态计算方法已被编成程序应用于精馏过程模拟。主要介绍了精馏过程的数学模型,国内外稳态精馏过程模拟计算方法的发展历程,归纳了几类主要稳态精馏过程模拟计算方法的应用及优缺点,旨在为稳态精馏过程模拟计算方法的后续研究提供基础。     

精馏过程稳态模拟计算方法的研究进展

精馏过程稳态模拟主要是针对实际精馏操作过程中精馏塔内的温度、压力、汽液相流量及汽液相组成分布进行分析,并通过模拟找到制约生产的瓶颈。稳态精馏过程模拟计算的难点是求解MESH方程组。国内外已经提出了许多稳态精馏过程模拟的计算方法,主要包括三对角矩阵法、牛顿法、内外层法、松弛法以及其他方法。精馏过程的数学模型及其求解方法直接影响到精馏过程模拟结果的准确性。随着计算机的发展,许多精馏过程的稳态计算方法已被编成程序应用于精馏过程模拟。主要介绍了精馏过程的数学模型,国内外稳态精馏过程模拟计算方法的发展历程,归纳了几类主要稳态精馏过程模拟计算方法的应用及优缺点,旨在为稳态精馏过程模拟计算方法的后续研究提供基础。     

间歇萃取精馏过程模拟计算

提出了一种可用于间歇萃取精馏过程模拟计算的快捷模型－准稳态模型，并对该方法的数学模型进行了推导。用此方法对间歇萃取精馏过程中塔顶、塔釜浓度，各塔板温度随时间的变化进行模拟，其结果与实验值吻合较好。它具有计算精度高、计算速度快等优点。     

理想热耦合精馏的特性研究

建立了理想热耦合精馏的模型,采用PRO/Ⅱ对此模型进行模拟计算,将计算结果与普通精馏过程对比,证明理想热耦合精馏的节能效果明显.通过研究精馏塔内温度和气液分布特点,提出了对塔内件的设计要求,分析了不同因素对理想热耦合精馏的影响.     

乙腈法萃取精馏丁二烯过程模拟与工艺优化Ⅰ.萃取精馏塔内各组分的摩尔分数、温度和气液流量的分布

采用Unifac基团结构法在乙腈法萃取精馏丁二烯装置中建立了乙腈-C4系统相平衡关系,利用PRO Ⅱ化工模拟软件对第一萃取精馏塔、第二萃取精馏塔内各组分的摩尔分数、温度和气液流量的分布进行了模拟计算,并对各分布曲线进行了系统分析。结果表明,在第一萃取精馏塔和第二萃取精馏塔中,各组分并非均匀分布,而是在特定的部分塔板分离,进而实现各组分按质量要求进行分离。     

DMF法萃取精馏异戊二烯过程模拟

异戊二烯作为裂解C5馏分中最重要的组成之一,为精细化工产品提供原料.本文介绍了二甲基甲酰胺(DMF)法萃取精馏法提取异戊二烯,利用PRO II 化工模拟软件对第一萃取精馏塔、第二萃取精馏塔内各组分的质量分数、温度和汽液流量的分布进行了模拟计算,并对各分布曲线进行了系统分析.结果表明,在第一萃取精馏塔和第二萃取精馏塔中,各组分并非均匀分布,而是在特定的部分塔板分离,进而实现各组分按质量要求进行分离.     

哌嗪精馏塔的模拟计算

以ChemCAD软件对哌嗪精馏塔进行模拟计算,以确定该精馏塔的理论板数、进料位置、各塔板的温度、压力及流率分布。模拟计算结果精馏塔的理论板数为22块,精馏可使哌嗪的质量分数达到99.38%。间歇精馏实验表明,实验值与模拟值基本吻合。     

大型反应精馏塔板上传质的二维定数混合池模拟

介绍了大型塔板涉及反应精馏的传质与操作过程,通过对塔板上液体流动分布以及化学反应过程的分析,建立了能够关联液体流速分布和化学反应的塔板液相浓度计算模型。最后将二维定数混合池模型与描述传质的微分方程联立,利用有限元法求解了大型反应精馏塔板上的液相浓度分布。     

一个用于精馏塔模拟的新模型

A new computational mass transfer model is proposed for simulating the distillation process by solving the fluctuating mass flux for the closure of turbulent mass transfer equation in order to obtain the concentration profile and the separation efficiency of distillation column. The feather of the proposed model is to abandon the conventional way of introducing the turbulent mass transfer diffusivity (dispersion coefficient) to the turbulent mass transfer equation. To verify the validity of the proposed model, a commercial scale packed column and a sieve tray column were simulated and compared with published experimental data. The simulated results were satisfactorily confirmed in both concentration distribution and separation efficiency.     

Modeling of batch extractive distillation

New data on the concentration profiles in a packed column during extractive distillation of benzene–heptane mixture in the presence of N-methylpyrrolidone as a separating agent have been obtained. A calculation method for the process based on partial mass transfer coefficients in the vapor and liquid has been proposed. The calculated and experimental data have been compared. It has been shown that both continuous and batch extractive distillation are calculated more precisely using the proposed model compared to the equilibrium model.     

On the modelling of mass transfer in extractive distillation

Mass transfer in extractive distillation in plate columns on a laboratory and pilot-plant scale was investigated experimentally by the separation of an azeotropic mixture, acetone—methanol, with water and 1,2-propylene glycol as solvents. The decrease in mass transfer efficiency with increasing solvent concentration was explained by a decrease and partial blocking of the interfacial area caused by the solvent. A mathematical model was established for mass transfer in extractive distillation on valve plates of diameter 0.4 m. This model was applied successfully to an industrial column.     

非理想多组分混合物中质量传递过程基于Maxwell-Stefan扩散理论的建模及数值分析(英文)

The Intalox metal tower packing was used to simulate an industrial relevant extractive distillation column for purifying azeotropic multicomponent mixture.In order to explain the inconsistencies in the modeling of transfer process in nonideal multicomponent distillation column,a method was developed with equilibrium stage models(EQ)and non-equilibrium model(NEQ)incorporated with Maxwell-Stefan diffusion equations in the framework of AspenONE  simulator.Dortmund Modified UNIFAC(UNIFAC-DMD)thermodynamic model was employed to estimate activity coefficients.In addition,to understand the reason for the diffusion against driving force and the different results by EQ and NEQ models,explicit investigations were made on diffusion coefficients, component Murphree efficiency and mass transfer coefficients.The results provide valuable information for basic design and applications associated with extractive distillation.     

分隔壁萃取精馏塔分离醋酸水溶液的模拟

提出了一种新的单塔萃取精馏精制醋酸水溶液的新工艺,该工艺采用分隔壁萃取精馏塔(DWC-E)替代常规萃取精馏流程的萃取精馏塔及溶剂回收塔,不仅节省了设备投资,而且降低了总能耗。利用Aspen Plus模拟软件,对DWC-E塔及常规萃取流程进行了模拟。DWC-E塔的操作条件:塔板数40块,侧线精馏段的板数10块,回流比2,溶剂摩尔比2.5,在此条件下,比较了常规萃取精馏流程与分隔壁精馏塔内温度、液相组成及汽液相流量的变化。结果表明,DWC-E塔比常规的2塔萃取精馏流程节能23.91%。     

计算传质法预测精馏塔效率(英文)

A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for de-sorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the ex-perimental measurement. The validation of the proposed model was further tested by comparing the simulated re-sult with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the strip-ping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray effi-ciencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column re-ported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.     

间歇萃取精馏制备高纯甲醇模拟与实验研究

针对工业甲醇制备高纯甲醇的间歇萃取精馏过程,建立了准稳态模型,采用Newton迭代法进行求解。模拟分析了影响高纯甲醇收率的溶剂流率、溶剂加入位置、回流比等因素,并通过实验验证了模型的准确性和可靠性。在实验与模拟计算的基础上,确定了工业甲醇制备高纯甲醇的最佳工艺条件:总理论板数35,萃取剂二甲基亚砜在第10块理论板加入,萃取剂与原料甲醇的体积比0.3,前馏分段回流比8,产品段回流比5,此时,高纯甲醇单程收率可达60%。     

Analysis of Energy‐Efficient Complex Distillation Options to Purify Bioethanol

Three complex extractive distillation options were studied for the purification of a dilute mixture of ethanol and water. The first option uses an extractive distillation column and the other two options use thermally coupled extractive distillation sequences. The results indicate that the fully thermally coupled extractive option can reduce energy consumption by ca. 30 % compared to the scheme that uses an extractive distillation column. This fully thermally coupled extractive distillation sequence can produce ethanol as distillate with a mass fraction of 0.995, the entrainer as the bottoms product and a mixture of ethanol and water as the sidestream.     

萃取精馏分离苯乙酮与α-苯乙醇的模拟研究

苯乙酮与α-苯乙醇属近沸点物系,用普通精馏方法很难将二者进行有效地分离。在对已报道的分离方法进行比较分析的基础上,提出了采用萃取精馏方法来分离苯乙酮和α-苯乙醇。文中首先通过定性判断和基团贡献法定量地估算选择了该二元物系合适的萃取剂为丙三醇。然后采用Aspen Plus化工模拟软件中的RadFrac模块进行了萃取精馏塔的模拟,分别考察了溶剂与原料进料位置、回流比、溶剂比对分离效果的影响。结果表明:对于处理量为1 000 kg/h的待分离物系,操作压力为5 kPa,在塔板数为30的条件下萃取精馏塔在原料进料位置为第19块塔板,溶剂进料位置为第6块塔板,回流比为3∶1(质量比),溶剂流率为800 kg/h的优化条件下,可以使塔顶苯乙酮质量分数达到99.8%,且塔釜几乎不含苯乙酮。模拟结果对进一步的实验研究和工业生产具有一定的指导意义。     

一种改进的多元精馏塔动态模型

综合了精馏塔的物料及能量平衡、塔板水力学方程、塔板效率及再沸器动态特性,给出一种改进的非理想多元物系精馏塔通用动态数学模型.增加了汽液平衡计算,从而弥补了文献[1]所提出的动态模型的缺陷,提高了其精度和通用性.模型仿真算法采用Gear积分方法,稳定性好,对解刚性比很高的精馏塔微分方程组十分有效.通过对某丙烯腈萃取精馏塔的仿真表明,该动态模型能够较好地反映对象的动态形为.