真空间歇精馏法精制双环戊二烯的研究

采用真空间歇精馏技术精制聚酯级双环戊二烯中的双环戊二烯,考察了操作压力、回流比、塔釜和塔顶温度对双环戊二烯质量分数和收率的影响,优化得到较佳精馏操作条件.实验结果表明:适宜的工艺条件为塔顶压力9kPa,回流比为3,塔釜温度为68～106℃,塔顶温度为45～87℃,在以上条件下,产品中双环戊二烯质量分数达到96％以上,收率达到90％以上,为工业化提纯双环戊二烯提供了实验依据.     

Multicomponent batch distillation with distillate receiver

Based on the assumption of adiabatic equilibrium stages, a rigorous calculation procedure applicable to a multicomponent batch distillation with a distillate receiver under total reflux condition was developed. Provided that the operating conditions including the desired product purity of the most volatile component in the receiver are specified, the proposed model estimates the volume of the distillate receiver, changes in compositions in the receiver and still, concentration profiles of the column, and the batch time required to complete the separation. In order to test the validity of the proposed model, experimental data for the separation of acetone-methanol-2-propanol mixture using a 10 cm I.D. column having six theoretical stages were compared with the simulation results for the two cases when the distillate receiver is initially empty and initially full.     

间歇萃取精馏分离环戊烷–四氢呋喃–环己烷

根据环戊烷–四氢呋喃–环己烷的汽液平衡关系,通过选择适当的溶剂(N,N–二甲基甲酰胺),提出了采用同一溶剂分离三元混合物的间歇萃取精馏方法.考察了溶剂比对该三元物系间相对挥发度的影响,进行了实验室小试研究.实验结果表明,所选溶剂N,N–二甲基甲酰胺可以增大环戊烷-四氢呋喃的相对挥发度,同时也可使四氢呋喃–环己烷共沸物的共沸现象消失,实验室萃取精馏小试可以得到纯度高于99%的环戊烷和环己烷产品.     

Recovery of lactic acid by batch reactive distillation

Lactic acid, being virtually a non‐boiling compound, is difficult to separate from its aqueous solution by conventional methods such as distillation. It is necessary to convert it to the relatively volatile ester and the separation of the ester, followed by hydrolysis, is recommended as an appropriate method of recovery. In the present work, we explore and investigate a novel reactive distillation strategy to perform esterification, distillation and hydrolysis in a single unit. The experiments were performed in a batch reactive distillation set‐up and the results have been explained with the help of an appropriate model. An unsteady state mathematical model based on an equilibrium stage concept was developed for batch reactive distillation. A pseudo‐homogeneous model was used for the determination of reaction kinetics. The effect of operating parameters such as feed concentration, mole ratio, catalyst loading, boil‐up rate, etc. on the recovery of lactic acid was studied with the help of simulation and experimental results. The feasibility issue of reactive distillation has been discussed based on the results obtained. Copyright © 2006 Society of Chemical Industry     

以苯胺为溶剂间歇萃取精馏分离甲醇-乙腈

提出和研究了以苯胺作为溶剂的甲醇-乙腈间歇萃取精馏分离工艺。根据溶剂极性相似相溶原理,结合ChemCAD软件模拟汽液平衡和汽液平衡实验确定苯胺为合适的溶剂。结果表明,不仅苯胺能够消除甲醇-乙腈物系的共沸现象,效果优于N,N-二甲基甲酰胺（DMF）,而且可以采用Wilson模型对苯胺作为溶剂的甲醇-乙腈共沸物系汽液平衡进行模拟。通过实验考察了间歇萃取精馏的分离效果。采用有33块理论板的填料塔进行间歇萃取精馏甲醇-乙腈共沸混合物分离实验,其中净化回收段填料层3块理论板,萃取精馏段填料层30块理论板,回流比为4,苯胺作为溶剂,溶剂质量比为2.5∶1时,在塔顶得到产品甲醇质量分数为98.97%,高于DMF作为溶剂时的95.76%;表明苯胺更加适合作为萃取精馏分离甲醇-乙腈共沸物系的溶剂。     

基于SIMULINK系统的间歇萃取精馏动态模拟

间歇萃取精馏属于非理想性极强的非稳态过程,很难找到一种快捷有效且易于执行的求解方法.基于此,分别建立了全回流开工、加溶剂全同流及产品采出3个阶段的平衡级动态模型,编写S函数将该模型求解过程嵌套于SIMULINK模块中,并在此基础上开发了间歇萃取精馏的动态模拟平台.通过将不同解法与实验值进行对比,确定了该研究条件下动态模型的求解策略:ODE45解法适于求解全回流开工和加溶剂全回流动态模型;ODE 15s解法和ODE 23s解法适于求解产品采出动态模型,其中ODE 23s的计算过程相对更快捷.     

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.     

间歇萃取精馏分离环己烷-正丙醇的研究

首次研究了间歇萃取精馏方法分离环己烷-正丙醇二元共沸物。通过溶剂选择原理选出DMF作为分离此共沸物系的溶剂,采用UNIFAC模型对常压下环己烷-正丙醇物系和加入溶剂DMF后的物系进行气液平衡模拟,并进行了实验验证,其中模拟结果与实验数据吻合较好。通过间歇萃取精馏分离此共沸物的实验研究来进一步考察所选萃取剂的效果。结果表明,DMF能够消除环己烷-正丙醇共沸物系的共沸点,采用有30块理论板的填料塔,萃取剂进料位置为第4块板,溶剂质量比为1∶1,回流比为3∶1时,塔顶环己烷产品质量分数为96.2%,回收率为72.2%。     

间歇反应精馏合成乙酸异丙酯

以乙酸和异丙醇为原料通过间歇式反应精馏合成乙酸异丙酯,正交实验给出最佳合成条件为:回流比3、反应时间1.5h、乙酸与异丙醇的物质的量比1∶1.5、催化剂用量为乙酸体积2%,乙酸异丙酯的最大收率为92.8%。     

间歇共沸精馏分离乙二醇单甲醚-水物系

通过绘制乙二醇单甲醚-水-共沸剂的简捷剩余曲线,提出了以乙酸异丙酯作为间歇共沸精馏法分离乙二醇单甲醚-水物系的共沸剂。然后完成剩余曲线数据的测定实验,根据实验数据绘制乙二醇单甲醚-水-乙酸异丙酯三元物系的剩余曲线图,确定了乙二醇单甲醚-水共沸物系的分离工艺。并通过实验研究了共沸剂加入量对乙二醇单甲醚回收率的影响,从而确定了适宜的共沸剂配比：当共沸剂与原料中水的质量比为2～2.5时,乙二醇单甲醚的一次性收率在90%以上。     

常规间歇萃取精馏分离苯-环己烷的研究

通过一个常规间歇萃取精馏实验装置,考察了不同萃取剂在不同回流比及萃取溶剂加入速率情况下对分离苯-环己烷共沸体系的影响。结果表明,二元混合溶剂能够解决单一溶剂的选择性与溶解性相矛盾的问题;且在同等条件下,综合性能优于单一溶剂;随着溶剂加入速率和操作回流比的增加,产品的产量逐渐提高,尤其重要的是混合溶剂间歇萃取精馏技术与简单溶剂间歇萃取精馏技术相比并不复杂。     

带有过渡段循环的多元间歇精馏优化计算

采用最大馏出量、最小时间及最大负荷因子作为目标函数,以采出速率作为优化变量,间歇精馏过程采用分段恒回流比操作,利用改进的模拟退火算法进行了带有过渡段循环的三元体系间歇精馏过程的优化。分别获得了3种目标函数下的最优操作条件及最优值,并与文献结果进行了比较。采用改进的模拟退火算法得到的优化计算结果均优于文献值。不同的目标函数下得到的优化操作策略不同,且随着过渡段循环次数的增加精馏过程趋于稳定。     

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。     

Feasibility of heterogeneous batch distillation processes

Synthesis of heterogeneous batch distillation is discussed, which aims at splitting azeotropic mixtures by adding an entrainer partially miscible with one of the initial binary mixture components. Key operational parameters are identified such as the amount of entrainer added in the ternary feed, the reflux policy, and the vapor line position by examples. Synthesis and operation are less straightforward for heterogeneous batch distillation than those for the homogeneous case, but offer many advantages: more design alternatives, simplified distillation sequences, a lower consumption of entrainer, and a crossing of distillation boundaries by the still path. Feasibility is assessed using simplified modeling and confirmed using a commercial batch process simulator package. Synthesis expectations and simulated results are verified throughout bench-plant experiments for the separation of the acetonitrile—water mixture using acrylonitrile as a light heterogeneous entrainer.     

减压间歇萃取精馏分离乙酸乙酯和乙醇

通过减压间歇萃取精馏实验装置,选用N,N-二甲基甲酰胺(DMF)作为萃取剂,对乙酸乙酯和乙醇二元共沸物系的分离进行了实验研究。考察了操作参数中操作压强、回流比(体积比)、溶剂比(体积比)对分离过程的影响。实验结果表明:减小压强、提高回流比和溶剂比都能不同程度地增强分离效果,实验得出减压操作情况下的间歇萃取精馏的较佳分离条件:操作压力为10 kPa,回流比为3,溶剂比为1,产品中乙酸乙酯的质量分数为97%以上。     

Cyclic total reflux batch distillation with two reflux drums

The present work proposes a novel cyclic total reflux (CTR) operation of batch distillation with two reflux drums working alternatively. A mathematical model is set up for the process. The computational comparison of the novel policy with the regular constant reflux and non-cyclic total reflux (NCTR) operations is also presented. The experimental runs of the new mode show that it can be operated and controlled more easily. The novel operation is significantly time saving compared to the mode of regular constant reflux theoretically and experimentally. The two reflux drum mode of CTR is also suitable for the separation of the mixture containing a large amount of light component.     

间歇精馏过程模拟的发展与应用

介绍了间歇精馏模拟过程中常用的数学建模的经典方法以及近两年在数学建模及其算法领域的发展,讨论各模型的特点及其在精馏工业和试验中的应用实例。     

混合溶剂间歇萃取精馏分离过程的模拟

由于混合溶剂存在"混合溶剂效应",能够解决简单溶剂选择性与互溶性相互矛盾的问题,因此混合溶剂间歇萃取精馏技术可以大大拓宽传统单一溶剂间歇萃取精馏分离技术的应用空间。文章建立了反映常规混合溶剂间歇萃取精馏过程的恒摩尔持液数学模型,并运用2点隐含法对其求解,结果表明,模拟计算结果与实验结果吻合较好。随后运用该模型探讨了塔身持液量、混合溶剂进料位置等因素对混合溶剂常规间歇萃取精馏的影响。得出以下结论,产品馏出速率随塔身持液量的增大而减小,塔顶馏分产量与塔身持液量的关系不大。另外,混合溶剂进料位置的选定对分离效果也有较大的影响,需要正确选择。     

Feasibility of separation of ternary mixtures by pressure swing batch distillation

Feasibility of the pressure swing batch distillation separation of ternary homoazeotropic mixtures in different single and double column configurations is investigated by assuming maximal separation. Feasibility regions where the ternary mixture can be separated into its pure components (by applying in at least one step pressure swing) and the separation steps for the recommended configurations are determined. The method is presented in details for the most frequent types of ternary mixtures with minimum azeotrope(s).     

间歇萃取精馏操作过程的实验研究

采用复合式精馏塔实现了萃取精馏的间歇操作,塔顶产品物质的量分数达95%以上。以取得合格产品的量与时间之比作为目标函数,研究了回流比R、中间回流量Vm(中间罐向提馏段进料流量)、萃取剂用量S对萃取精馏过程的影响,在R=5～10,Vm=3.2～7.2mL/min,S=1.2～2.2mL/min范围内,随以上操作参数的增大,目标函数均呈先增大后减小的趋势。