醇-水体系汽液相平衡的盐效应及其在精馏过程的应用

加盐精馏是一种新型分离技术。本文讨论了盐对醇-水体系汽液相平衡的影响,并在理论上进行了探讨。进而论述了加盐精馏在醇-水体系分离过程的应用,包括溶盐精馏、加盐萃取精馏和加盐反应萃取精馏等,并讨论了它们的优缺点。最后,展望了加盐精馏分离醇-水体系的发展。     

利用溶盐精馏法分离乙醇—水体系的研究

乙醇浓度达到95.57%时,乙醇—水形成共沸体系无法继续分离,必须通过其他途径实现无水乙醇的制备。目前工业上采用共沸精馏、萃取精馏、溶盐精馏等方法制备无水乙醇。本文采用溶盐精馏法,研究无水氯化钙及醋酸钾在乙醇—水体系中的分离作用。     

加盐萃取精馏分离酯水溶液的研究

将加盐精馏和萃取精馏结合起来的加盐萃取精馏新方法,由醋酸甲酯-水体系的汽液平衡试验结果表明,盐的加入破坏了共沸点组成,加盐萃取精馏比单纯的加盐精馏和萃取精馏工艺更优.     

盐效应制取无水乙醇的研究现状及发展前景

无水乙醇广泛应用于制药、化工、能源等行业,需求量日益剧增。目前,利用盐效应制取无水乙醇的方法主要有溶盐精馏、加盐萃取精馏。文章对盐效应方法做了分析,对盐的选择和盐效应在分离工艺中的研究进展做了详细的阐述。     

燃料乙醇制备方法研究进展

综述了燃料乙醇制备方法的研究进展。介绍了溶盐精馏法、萃取精馏法、加盐萃取精馏法、吸附法及渗透汽化法等多种乙醇脱水提纯的方法,并对上述方法作用机理及特点进行对比。其中,吸附法能在常温常压下吸附脱除乙醇中的水,如能通过研究,进一步降低再生成本,是一项具有广阔前景的燃料乙醇制备技术。     

溶剂加盐对乙醇—水分离效果的研究

无水乙醇是指纯度为99.5%以上的乙醇,乙醇在水中形成的是一种二元共沸体系,故不能用一般的方法制取无水乙醇。工业中比较有效果的两种分离方法:溶盐精馏和萃取精馏,两种方法都有各自的缺点,采用加盐萃取精馏的方法,研究新型萃取剂丙三醇+氯化锌对乙醇—水体系分离的影响。     

工业生产中醋酸甲酯回收技术的研究进展

综述了聚乙烯醇和精对苯二甲酸生产过程中分离回收醋酸甲酯的主要方法,并对加盐萃取精馏等盐效分离方法、催化精馏方法和萃取精馏方法进行比较研究。结果表明,加盐萃取精馏方法能分离出高纯度醋酸甲酯,且生产工艺简单,有较好的应用前景。     

新型分离法回收制药废液中四氢呋喃

为了从制药废液中回收四氢呋喃 ,研究了萃取精馏技术和加盐萃取精馏技术在分离甲醇 四氢呋喃 水体系中的应用 ,选择了萃取精馏及加盐萃取精馏所用溶剂 ,设计了工艺流程 ,确定了操作条件 ,采用以上技术从废液中回收的四氢呋喃 ,纯度可达到 99.5 % (质量 )     

乙醇-水体系分离技术研究进展

乙醇是重要的化工有机原料之一，被广泛应用于医疗、化妆品、卫生用品、油脂及染料等领域，与人们生活息息相关。乙醇作为一种二次清洁能源，成为各个国家能源工业发展的热点。主要介绍了乙醇-水体系分离技术（包括吸附分离、膜分离、共沸精馏、萃取精馏、溶盐精馏及加盐萃取等）的研究现状和发展前景。     

加盐萃取精馏分离邻二甲苯-苯乙烯的研究

测定了不同萃取剂和盐对邻二甲苯-苯乙烯近沸程物系相对挥发度的影响,研究了盐质量浓度、萃取剂加入速率和回流比对加盐萃取精馏的影响,并建立了反映塔顶馏出液中邻二甲苯质量分数与各因素关系的回归模型。研究结果表明,环丁砜(DMSO)-水(质量分数3%)-硫氰酸钾(KCNS,0.03 g/mL)可作为加盐萃取精馏分离邻二甲苯和苯乙烯体系的最佳加盐萃取剂。     

Reducing the energy demand of corn‐based fuel ethanol through salt extractive distillation enabled by electrodialysis

The thermal energy demand for producing fuel ethanol from the fermentation broth of a contemporary corn‐to‐fuel ethanol plant in the U.S. is largely satisfied by combustion of fossil fuels, which impacts the possible economical and environmental advantages of bioethanol over fossil fuels. To reduce the thermal energy demand for producing fuel ethanol, a process integrating salt extractive distillation—enabled by a new scheme of electrodialysis and spray drying for salt recovery—in the water‐ethanol separation train of a contemporary corn‐to‐fuel ethanol plant is investigated. Process simulation using Aspen Plus® 2006.5, with the electrolyte nonrandom two liquid Redlich‐Kwong property method to model the vapor liquid equilibrium of the water‐ethanol‐salt system, was carried out. The integrated salt extractive distillation process may provide a thermal energy savings of about 30%, when compared with the contemporary process for separating fuel ethanol from the beer column distillate. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Reducing the Energy Demand of Cellulosic Ethanol through Salt Extractive Distillation Enabled by Electrodialysis

One of the main challenges when a biochemical conversion technique is employed to produce cellulosic ethanol is the low concentration of ethanol in the fermentation broth, which increases the energy demand for recovering and purifying ethanol to fuel grade. In this study, two design cases implementing salt extractive distillation—with salt recovery enabled by a novel scheme of electrodialysis and spray drying—along with heat integrated distillation techniques of double-effect distillation and direct vapor recompression are investigated through process simulation with Aspen Plus® 2006.5 for reducing the thermal energy demand. Conventional distillation along with molecular sieve based dehydration is considered as the base case. Salt extractive distillation along with direct vapor recompression is found to be the most economical ethanol recovery approach for cellulosic ethanol with a thermal energy demand of 7.1 MJ/L (natural gas energy equivalents, higher heating value), which corresponds to a thermal energy savings of 23% and cost savings of 12% relative to the base case separation train thermal energy demand and total annual cost.     

加盐反应萃取精馏分离醇水溶液

将加盐萃取精馏和反应萃取精馏结合起来提出了加盐反应萃取精馏分离醇水溶液的新方法。由异丙醇－水体系的汽液平衡试验结果表明加盐反应萃取精馏比单独的加盐萃取精馏更优,工艺试验证明当溶剂为1：1时,容易得到产品纯度96％以上的异丙醇。     

加盐萃取精馏的研究进展

阐述了加盐萃取精馏的原理和定标粒子理论在加盐萃取精馏中的应用,对加盐萃取精馏分离极性物系和非极性物系的现状进行了评述,并提出了若干需要深入研究的问题。     

A new process for fuel ethanol dehydration based on modeling the phase equilibria of the anhydrous MgCl2 + ethanol + water system

The use of ethanol as a fuel for motor engines has attracted significant attention because of its possible environmental and economic advantages over fossil fuel. However, the energy demand for the ethanol dehydration process significantly impacts its production cost. A new and energy efficient process is developed on the basis of salt extractive distillation, which uses recycled MgCl₂ granules as a separating agent. Vapor‐liquor‐equilibria (VLE) data for the ternary MgCl₂ + ethanol + water system, and the three constituent binary systems were measured at 30, 60, 90, and 101.3 kPa. A large enhancement of relative volatility of the ethanol + water system in the presence of MgCl₂ is observed throughout the entire ethanol concentration range, which completely broke the azeotrope. The salt effect of MgCl₂ is thought to be the result of energetic interactions and the hydration equilibrium reaction of the Mg²⁺ ion with water molecules. The calculation results by the mixed‐solvent electrolyte model embedded in the OLI platform equipped with new model interaction parameters and equilibrium constant (obtained via the regression of experimental VLE data), provided for a satisfactory means of simulating the MgCl₂ salt extractive distillation process. Finally, the process was proven feasible at the laboratory‐scale resulting in large granules of recovered MgCl₂ and a product of 99.5 wt % ethanol. © 2014 American Institute of Chemical Engineers AIChE J, 61: 664–676, 2015     

加盐萃取精馏法制无水异丙醇过程模拟

对加盐萃取精馏法制备无水异丙醇过程进行了模拟计算,采用有序双液程(NRTL)模型对异丙醇-水-乙二醇-醋酸钾体系异丙醇-水气液平衡数据进行了回归,得到了该条件下的NRTL交互作用参数,在此基础上采用Aspen软件进行模拟计算;对理论塔板数、回流比(质量比)与进料位置进行了优化,模拟结果与现场数据吻合较好,说明采用的方法适用于加盐萃取精馏过程的模拟。