共沸精馏分离乙醇-异丙醇

为了分离乙醇-异丙醇混合物,研究了共沸精馏在乙醇-异丙醇物系中的应用。根据共沸剂的选取原则选定出1-己烯作为共沸精馏分离乙醇-异丙醇混合物的共沸剂,使用ASPEN模拟软件模拟连续和间歇共沸精馏分离乙醇-异丙醇工艺流程,并通过间歇共沸精馏实验考察了所选共沸剂的分离效果。结果表明：使用1-己烯作为共沸剂能成功的分离乙醇-异丙醇混合物;采用有30块理论板的填料塔,回流比为25,共沸剂1-己烯与乙醇的质量比为4∶1,塔釜异丙醇的质量分数达到99.77%。     

共沸精馏在丙烯醇脱水工艺中的应用

南京树脂厂生产中,产生一定数量的含水丙烯醇,为了回收利用,采用共沸精馏脱水工艺,可得到合格丙烯醇。本文就共沸剂的选择、工艺、装置与操作作了介绍.     

异丙醇-水间歇共沸精馏模拟研究

运用两点隐含法求解间歇共沸精馏过程平衡级恒摩尔持液模型的非线性刚性方程组。以异丙醇-水-环己烷为例进行模拟计算,并将模拟计算结果同实验结果相比较。结果表明,当共沸剂塔顶回流的回流比为1∶5时,分离得到的异丙醇浓度可以达到99.5%(质量分数);异丙醇的收率最高,最大收率可达78%;模拟计算结果与实验结果吻合得较好,模拟计算可以反映实际过程。     

用共沸反应精馏制取叔丁醇钾的工艺设备及放大

采用将反应和共沸精馏结合为一体的工艺和具有大比表面积的填料塔,由氢氧化钾制取叔丁醇钾。小试及放大研究表明氢氧化钾的转化率达到９３％以上。     

叔丁醇脱水制异丁烯的共沸反应精馏过程研究

以环己烷为共沸剂,磺酸树脂为催化剂对叔丁醇常压脱水共沸反应精馏工艺进行了模拟和实验研究,实验验证了该工艺制备异丁烯的可行性。通过Fortran编写动力学子程序接口,以NRTL为热力学模型,采用Aspen Plus建立反应精馏模型对该过程进行模拟,模拟结果与实验结果吻合较好,证明模拟计算方法是可靠的。进一步通过模拟计算考察了塔顶冷凝温度、分相器温度、塔板数、上升蒸汽量、进料位置、叔丁醇水溶液质量分数对共沸反应精馏过程的影响,获得在进料流率0.25 g/min、催化剂填充量为10 g时的最佳工艺条件:塔顶冷凝温度和分相器分别为2℃和50℃,总塔板板数为6块,上升蒸汽量为3.0 g/min,叔丁醇进料位置为2—5块板。在此最佳条件下,当进料中叔丁醇质量分数在75%以上时,叔丁醇的转化率达到96.00%以上。     

共沸精馏中共沸剂的选择

1前言在化工生产中，生产原料、中间产品和最终产品都需要采用适当的分离方法而达到一定的纯度，而最常用和最有效的分离方法是“精馏”。然而当被分离物系组分间的相对挥发度接近于1或等于1时，采用普通精馏方法分离这样的物系，在经济上是不合理的，在技术上也是不可能的。因此需采用某些特殊精馏方法，如共沸精馏方法来实现分离的目的。所谓共沸精馆分离方法是向待分离系统中加入一个新组分，而加入的新组分和被分离物系中一个或几．八分形成最低共沸物，并从塔顶蒸出，所加入的新组分Ji‘1共沸刑或挟带剂．在共沸精馏过程中，共沸剂选…     

隔壁共沸精馏塔分离异丙醇水溶液的模拟

提出一种单塔共沸精馏生产无水异丙醇的新工艺流程,即采用隔壁塔替代常规共沸精馏流程中的脱水塔及提浓塔。应用Aspen Plus模拟软件,对隔壁共沸精馏塔流程及常规共沸精馏流程进行了模拟,比较了两种流程的液相组成、温度、汽液相流量及能耗,结果显示新工艺流程可以节省能耗14.6%,并能降低设备投资费用和操作费用。其模拟结果还需试验进一步验证。     

间歇恒沸精馏法从异丙醇水溶液中回收异丙醇

采用单塔间歇恒沸精馏法将异丙醇与水分离,从含水１２．６％左右的醇溶液可制得含水小于０．５％的异丙醇产品,醇的回收率达９７．０％。对恒沸剂选择、用量,流程和操作要点作了推荐及说明     

非均相共沸精馏研究进展

非均相共沸精馏广泛应用于共沸物和近沸物的分离。文章介绍了非均相连续共沸精馏和非均相间歇共沸精馏关键技术的研究进展。对共沸精馏中的关键问题如共沸剂的选择做了详细论述和验证。利用残余曲线法对非均相共沸精馏的过程可行性进行了分析和讨论。     

乙醇脱水塔内两相和三相共沸精馏

研究了乙醇脱水塔内的两相共沸精馏和汽液液三相共沸精馏过程。利用Aspen plus模拟软件对乙醇脱水塔内4种工况的精馏曲线、共沸剂浓度分布、回流量和再沸器能耗进行了分析比较。结果表明,苯做共沸剂时,脱水塔内两相共沸精馏和汽液液三相共沸精馏的精馏曲线、共沸剂浓度分布、回流量和再沸器能耗相近,脱水塔精馏曲线都跨越了精馏边界,并且共沸剂在塔内大多数板上都有较高浓度分布。而环己烷做共沸剂时,两相共沸精馏工况和汽液液三相共沸精馏工况条件下的脱水塔内精馏曲线、共沸剂浓度分布、回流量和再沸器能耗有较大差别。汽液液三相共沸精馏工况条件下,环己烷在塔内大多数板上有较高浓度分布,起到较好的脱水作用,而两相共沸精馏工况条件下脱水塔内共沸剂仅分布在塔顶几块塔板上,塔内多数板上没有起到共沸剂作用。     

共沸蒸馏脱水技术在纳米材料制备中的应用

介绍了共沸蒸馏脱水的基本原理和置换剂的选择条件,综述了共沸蒸馏脱水技术在纳米材料制备中的应用,探讨了共沸蒸馏脱水在纳米粉体制备过程中的防团聚机理,指出了共沸蒸馏脱水技术目前还存在的问题和今后的研究方向.     

Implementation of Ethanol Dehydration Using Dividing-Wall Heterogeneous Azeotropic Distillation Column

In this article, the design and optimization procedures of a dividing-wall column for heterogeneous azeotropic distillation (DWC-A) using cyclohexane as an entrainer for ethanol dehydration are investigated. The proposed procedures can detect the optimal values of the design variables and thereby guarantee the minimum energy requirements, which is related to the minimum CO₂ emissions and the lowest total annual cost (TAC). Since ethanol and water form an azeotrope under atmosphere pressure, a conventional heterogeneous azeotropic distillation sequence (CHADS), including an azeotropic column and a recovery column, is usually used to perform the ethanol dehydration process. However, due to high energy requirements and equipment investments of CHADS, the TAC is at a relatively high level. DWC-A can be used to eliminate the condenser of the second column and decrease the degree of back-mixing. Both CHADS and DWC-A are simulated with Aspen Plus®, and the results show that DWC-A has an energy saving of 42.17% and the TAC reduction of 35.18% along with higher thermodynamic efficiency and reduction in greenhouse gas emissions.     

催化精馏塔装填方式的研究进展

综述了催化精馏塔催化剂的 4种装填方式 ,即板式塔装填方式、填充式装填方式、悬浮式装填方式和催化剂散装填料的技术进展 ,介绍了这些方式的优缺点及适用范围 ,提出了装填方式的发展趋势。     

Strategies for Starting Up Azeotropic Distillation Columns with Multiple Steady States

The operability of azeotropic distillation columns with multiplicity is analysed during start‐up by dynamic simulation. Different steady states can be reached by applying different start‐up configurations and/or policies. The well‐known benzene‐heptane‐acetone (BHA) system is studied. The process by which the column reaches these steady states can be seen through the examination of profile evolutions corresponding to the given start‐up policies. Indeed, a clear partition of the start‐up policies space yielding different solutions is achieved. Some properties of this space are explained and start‐up critical values can be identified. Finally, some guidelines for start‐up supervision are outlined for the study case.     

规整填料内气液两相流动与传质的计算传质学模型

Detailed investigation of flow behavior in structured packing distillation columns is of great importance in accurate prediction of process efficiency and development of more efficient and optimal equipment internals. In this study, a three-dimensional two-phase flow model based on VOF method for simulating the hydrodynamics and mass-transfer behavior in a typical representative unit of the structured packing is developed. In the proposed model, the model is used for the closure of turbulent mass transfer equation. By solving the proposed model, the velocity distribution, phase fraction profile and concentration field are obtained. Using these data, the total liquid holdup, the wetted area and the separation efficiency [height equivalent to a theoretical plate (HETP)] are estimated. For testing the model validation, the simulated HETPs are compared with our previous experimental data obtained in a 150 mm-diameter column containing Mellapak 350Y operating at the pressures of 0.6-1.8 MPa. The compari-son shows that they are in satisfactory agreement, with an average absolute deviation (AAD) of 25.4%.     

萃取精馏分离乙腈-正丙醇的研究

采用萃取精馏的方法分离乙腈-正丙醇的共沸物系。首先利用溶剂选择原理和UNIFAC基团贡献法选出N-甲基吡咯烷酮作为萃取精馏的萃取剂,同时采用NRTL模型对常压下乙腈-正丙醇物系和加入萃取剂N-甲基吡咯烷酮后的汽液平衡进行模拟和实验验证,模拟结果与实验数据吻合较好。然后通过间歇萃取精馏实验进一步考察所选萃取剂的分离效果。结果表明,N-甲基吡咯烷酮能够打破共沸,有效分离乙腈-正丙醇共沸物系。采用有28块理论板的填料塔,萃取剂进料位置为第4块板,溶剂比为1.0,回流比为3,可以从塔顶得到质量分数为98.6%的乙腈产品。最后,用Aspen Plus软件对乙腈-正丙醇物系的连续萃取精馏流程进行了模拟,得出的参数为进一步的工业应用奠定基础。     

PBT废水共沸精馏提纯THF的方法

利用THF-水体系在不同压力下共沸物组成差异大的特点,选择合理的差压精馏方案,结合少量杂质侧线出料,THF再精制,实现PBT废水中THF的提纯。THF质量分数计算值达到99．99％,排放废水中水含量99．9％,耗能200kJ／mol THF。     

Dehydration of Ethanol-Water Azeotropic Mixture by Adsorption Through Phillipsite Packed-Column

Abstract

Phillipsite is a natural zeolite material available in several locations in Jordan. Phillipsite with and without treatment was used for dehydrating ethanol in the adsorptive distillation process. Molecular sieves 4A was taken as a reference material. According to the breakthrough curves phillipsite treated with 1 M calcium chloride solution gave the best performance. The water uptake using the 1 M-phillipsite was 0.1054 g H₂O/g adsorbent while the water uptake using the 4A molecular sieves was 0.1030 g H₂O/g adsorbent. The Guggenheim, Anderson, and De Boer (GAB) model and the Frenkel, Halsey, and Hill (FHH) model were used to represent the isotherms for water sorption on the adsorbents used. The GAB model fit the experimental data relatively better than the FHH model for all cases, except for the case of using 2 M-phillipsite. Using the Crank diffusion model the effective diffusivity of water vapor in raw phillipsite is 10.40 × 10^?8 mm²s^?1 while it is 6.9 × 10^?8 mm²s^?1 in the 1 M treated phillipsite.