间歇共沸精馏法回收制药废液中的乙醇

结合制药厂的规模、现有设备等实际情况,研究了以正己烷作为共沸剂,采用间歇共沸精馏法回收该厂生产废水中乙醇的过程,得到了该条件下间歇共沸精馏的流程,以及共沸剂正己烷与乙醇的最佳配比、回收水相中的共沸剂正己烷和原料乙醇时适宜的回流比等操作参数.实验结果证明,该方法可行并且是经济的.     

间歇共沸精馏法回收制药废液中的乙醇

结合制药厂的实际情况,研究了以正己烷作为共沸剂,采用间歇共沸精馏法回收该厂生产废液中乙醇的过程,得到了该条件下间歇共沸精馏的工艺流程,以及共沸剂正己烷与乙醇的最佳配比、回收正己烷及乙醇时适宜的回流比等操作参数.实验结果证明,该方法是经济可行的.     

1,1,2-三氯乙烷生产工艺的研究进展

1,1,2-三氯乙烷在化学工业中十分重要,可以用来作溶剂、萃取剂、杀虫剂,并且可以用于医学领域起麻醉作用,也可以是制作修正液的原料以及用来生成1,1-二氯乙烷。综述了氯乙烯氯化法、塔式合成法、1,2-二氯乙烷反应精馏法、利用烯烃混合废气法、共沸精馏法等1,1,2-三氯乙烷的生产方法。     

非均相共沸精馏法分离2-氯乙醇-水

以环己烷、甲苯和1,2-二氯乙烷为候选共沸剂,采用非均相共沸精馏法从2-氯乙醇/水共沸物中分离出高浓度2-氯乙醇产品。通过ASPEN物性分析功能研究了不同共沸剂与2-氯乙醇/水体系形成共沸物的情况,并根据三元相图进行了过程的概念设计。在此基础上,通过ASPEN模拟和优化了采用不同共沸剂的分离过程的工艺条件,并以年度总费用最小为依据选择了甲苯为共沸剂,此时最优工艺条件为:共沸塔总理论板数为20块塔板,进料位置在第8块塔板,回流比为2;脱水塔总理论板数为30块塔板,进料位置在第20块塔板,回流比为1.5。在此工艺条件基础上进行了实验,结果表明2-氯乙醇产品纯度可达到99%以上,且回收率在93.5%,实验结果与模拟结果能较好吻合,文中的研究可为2-氯乙醇-水分离的工业化提供参考。     

非均相共沸间歇精馏模拟

提出了非均相共沸间歇精馏过程计算模型。将共沸精馏塔分为再沸器，塔体，冷凝器和液相分层器几部分，用Newton-Raphson法与泡点法结合对这4个部分进行迭代计算。经实例模拟表明，操作条件指定合理，本模型只需要用很简单的初值，能以较快的速度收敛到正确解。本模型对间歇精馏操作具有一定的指导作用。     

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…     

1,1,2-三氟三氯乙烷转产为1,1,1-三氟三氯乙烷的新方法

1,1,2-三氟三氯乙烷(CFC-113)是亟需淘汰的消耗臭氧层物质(ODS)之一,而其同分异构体1,1,1-三氟三氯乙烷却属于非ODS物质。介绍了以CFC-113为原料转产为CFC-113a的技术进展,并使用了一种新型添加剂和调节剂,使其转化率达到了99.5%以上,极大地提高了产率。并且省去了精馏的过程,节约了成本。     

萃取、共沸精馏技术联用回收废液中的醋酸

针对化工生产过程中产生的稀醋酸溶液难以回收高纯度醋酸的问题,首先采用乙酸乙酯和苯的混合溶剂萃取浓缩稀醋酸溶液;再通过精馏蒸出溶液中的萃取剂和部分水;最后采用乙酸丁酯作为挟带剂,用共沸精馏法分离得到醋酸。得到的醋酸质量分数达96.84%,回收率达84.97%。对工业化回收稀醋酸溶液中的醋酸有一定的实用价值。     

共沸精馏法对苯酚-水混合物的分离

在双酚A生产中，缩合反应产生的水和过量的苯酚形成大量苯酚-水混合物。脱除混合物中的水和回收苯酚供缩合反应循环使用，是双酚A生产工艺中非常重要的单元操作。由于苯酚和水能形成共沸物，因此不能用普通精馏方法将它们分离。如果在苯酚-水物系中加入一种共沸剂甲苯，使甲苯与水形成更易分离的甲苯-水共沸物，用共沸精馏法即可实现苯酚-水混合物的分离。分离后的水可以直接送到生化装置进行处理，苯酚回收供反应系统循环使用。     

共沸法回收吡啶的研究和设计

介绍了利用共沸精馏的方法,对比选择不同共沸剂进行高纯度吡啶回收的理论和实验研究,设计出合适的工艺流程和工艺条件,得到了满意的结果。并在实验数据的指导下设计建立了一套工业装置,得到了纯度大于99.5%的吡啶产品。实践证明,用共沸精馏的原理所设计的分离工艺对于处理一系列含水共沸物系是行之有效的。     

1,2-二氯乙烷反应精馏制备1,1,2-三氯乙烷

以1,2-氯乙烷和氯气为原料,用反应精馏法制备1,1,2-三氯乙烷,并考察了反应温度,1,2-氯乙烷进料位置、填料类型和空塔气速对反应的影响。结果表明,较好的条件为1,2-氯乙烷进料位置在塔的中上段,反应段温度为105-110℃,增大空塔气速和使用规整填料能明显提高1,1,2-三氯乙烷的选择性和生成速率。     

具有最低共沸点难分离物系变压精馏分离

变压精馏是根据物系压力改变引起液体混合物共沸点组成变化,进而使共沸物系得以分离的一种有效分离方法。具有最低共沸点的液体混合物分离是化工过程中常见的分离难题。本文在热力学分析基础上研究了四氢呋喃与乙醇、环己烷与苯混合物这类典型的最低共沸液体混合物的变压精馏可行性,提出变压精馏分离四氢呋喃-乙醇液体混合物工艺流程,以NRTL-RK为物性计算方法,利用Aspen Plus模拟软件对变压精馏分离工艺过程进行分析及模拟,并对工艺参数进行优化。结果表明:在常压塔和8atm高压塔组成的双塔流程中变压精馏能将四氢呋喃-乙醇最低共沸混合物进行较好的分离,指出本文提出的研究方法可为具有最低共沸点液体混合物分离工艺的建立提供更加有效的指导。     

PBT废液回收焚烧处理

采用有机热载体炉焚烧处理了PBT生产过程中四氢呋喃三级蒸馏回收后排放的有机废液。消除了四氢呋喃有机废液储存及运输安全隐患,增加了有机热载体炉热量供给,达到了节能减排保护环境的目的。     

A review of extractive distillation from an azeotropic phenomenon for dynamic control

Extractive distillation is an effective method for separating azeotropic or close boiling point mixtures by adding a third component. Various technologies for performing the extractive distillation process have been explored to protect the environment and save resources. This paper focuses on the improvement of these advanced technologies in recent years. Extractive distillation is retrieved and analyzed from the view of phase equilibrium, selection of solvent in extractive distillation, process design, energy conservation, and dynamic control. The quantitative structure–property relationship used in extractive distillation is discussed, and the future development of extractive distillation is proposed to determine how the solvent affects the relative volatility of the separated mixture. In the steady state design, the relationship between the curvature of the residue curve and parameters of the optimal steady state is also highlighted as another field worthy of further study to simplify the distillation process.     

催化精馏脱除乙醇-水共沸混合物中水的模拟研究

采用异丁烯(IB)水合生成叔丁醇(TBA)的方法和催化精馏工艺脱除乙醇中的水.选用Equilibrium模型描述催化精馏塔中反应段的反应过程.应用Aspen Plus系统的讨论了操作压力、塔顶采出率(D/F)、回流比、异丁烯/水摩尔进料比、进料位置、反应段位置、理论板数对脱水效果的影响.结果表明,在较少能量消耗下,异丁烯很容易水合生成叔丁醇,但是叔丁醇选择性较低,生成乙基叔丁基醚(ETBE)的反应占主导.当采用叔丁醇选择性高的催化剂,通过催化精馏,能够在较低的能耗和较少的IB消耗下实现乙醇的脱水.     

Analysis of closed multivessel batch distillation of ternary azeotropic mixtures using elementary VLE cells

Introducing the concept of elementary topological cells, we illustrate how vapor-liquid equilibrium (VLE) diagrams like distillation lines and isotherms maps may be used in analysis of the closed (total reflux) multivessel batch distillation column. An indirect level control strategy is implemented that eliminates the need for pre-calculated vessel holdups and makes the closed operating policy flexible and simple to implement in practice.     

催化反应精馏脱除异丁醇-水共沸物中水的工艺模拟

基于异丁烯的催化水合反应生成叔丁醇的原理,提出了催化反应精馏脱除异丁醇-水共沸物中水的方法.应用Aspen Plus模拟软件,选用Equilibrium模型描述精馏塔中反应段的催化反应过程,利用软件中的Radfrac模块模拟催化反应精馏塔.研究了反应段塔板数、操作压力、回流比、烯醇比、理论板数等工艺参数对脱水效果的影响.研究结果表明,采用NKC-9强酸型树脂催化剂作填料,在优化得到的工艺操作条件下,通过催化反应精馏的方法,异丁醇-水共沸物中水的脱除率高达99.8％.     

Energy saving in acetic acid process using an azeotropic distillation column with a side stripper

Dilute acetic acid is obtained primarily from fermentation and synthesis processes and cannot be produced by simple distillation due to relatively low volatility of acetic acid compared to water. Instead, an azeotropic distillation is applied to increase the concentration of dilute acetic acid. When acetic acid is extracted from a dilute aqueous solution using a solvent mixture of ester and alcohol, its recovery requires an energy-intensive azeotropic distillation. In the water stripping process that follows azeotropic distillation, two distillation columns handle the acetic acid and water mixture in similar composition. Therefore, the two columns can be combined as a side stripper connected to the azeotropic distillation column. The energy-saving effect is examined with the HYSYS (Aspentech Corporation) evaluation of the process. Compared to the conventional process, the modified process suggests 39% reduction in heating duty and 24% coolant savings. The economic analysis shows 32% decrease in investment and 36% utility savings. Based on heat utilization analysis, the thermodynamic efficiency is enhanced by 11%.     

Studies on the feasibility of electrochemical recovery of palladium from high-level liquid waste

The electrochemical behavior of palladium (II) in nitric acid medium has been studied at platinum and stainless steel electrodes by cyclic voltammetry. The cyclic voltammogram consisted of a surge in cathodic current occurring at platinum electrode at a potential of −0.1 V (vs. Pd), which culminates in a peak at −0.3 V was due to the reduction of Pd(II) to Pd. This was accompanied by a broad scant anodic peak at 0.25 V during scan reversal. Reduction of Pd(II) was irreversible and the diffusion coefficient was found to be 2.35 × 10⁻⁸ cm²/s at 298 K. At stainless steel electrode, a surge in the cathodic current occurring at −0.4 V (vs. Pd) was due to palladium deposition, which was immediately followed by a steep increase in cathodic current at −0.66 V due to H⁺ reduction. Electrolysis of palladium nitrate from 1 M to 4 M nitric acid medium at stainless steel electrode resulted in complete recovery of palladium with reasonably high Faradaic efficiency depending upon nitric acid concentration. However, the recovery and Faradaic efficiency were significantly lowered (to 40%) in the case of electrolysis from simulated high-level liquid waste due to other interfering competitive reactions.