醋酸生产精馏装置改造的研究

吉化电石厂的醋酸生产目前仍采用乙醛氧化法制取醋酸的工艺技术,精馏工艺采用的流程为高低高的双塔精馏方式.鉴于此,本研究采用的工艺为单塔精馏,减小物料在精馏过程中的停留时间,以达到节能、省时、减少费用的目的,避免双塔精馏所造成的设备与能源的浪费.     

大型醋酸直接精馏系统的改造设计

引言 醋酸/水体系的直接精馏是一个非常特殊的汽液分离过程，这里所述的直接精馏指的是普通精馏而非共沸精馏或萃取精馏。该体系在精馏操作过程中不仅具有严重的腐蚀性，因而要求较高标号的设备用材，而且需要较多的理论塔板数，以实现较高的分离要求。尤其是在塔上部至塔顶部分，     

气相色谱法测定醋酸仲丁酯装置醋酸精馏塔顶物的组成

文章介绍了利用Agilent7820色谱,对醋酸仲丁酯装置醋酸精馏塔顶物分析方法的创新。此方法采用GDX-103 2 m*3 mm不锈钢填充色谱柱,TCD检测器,校正归一化法定量,分析结果符合定性定量要求,快速、简捷、准确度高。     

几种醋酸精馏工艺的比较

对三种改进后的醋酸精馏工艺进行较，分别适合于不同的公用工程，仪表，设备等条件。     

反应精馏回收糠醛生产中产生的甲酸和醋酸

二步法甲酸/醋酸催化玉米芯生产糠醛工艺的水解过程会产生少量的醋酸和甲酸,因此水解液中醋酸和甲酸的质量分数不断增加。为了使糠醛生产中甲酸和醋酸质量分数适合工艺条件,文中采用反应精馏法回收该工艺中过量的醋酸和甲酸。分别考察了回流比、酸水进料流量、甲醇与醋酸进料摩尔比、醋酸质量分数和甲酸质量分数等因素对反应精馏回收甲酸和醋酸效果的影响。通过实验得出了适宜的工艺条件:对甲酸质量分数在0.5%以上、醋酸质量分数20%以下的水解液,酸水进料流量在9.0 mL/min、甲醇醋酸进料摩尔比为3∶1和回流比为5等条件下的处理效果最佳。最佳反应条件下对于醋酸质量分数为20%的水解液,醋酸转化率为50.4%,同时甲酸质量分数降低到0.5%。实验证明此方法在满足二步法生产糠醛工艺对水解液甲酸和醋酸质量分数的要求的同时,可回收过量的甲酸和醋酸。     

醋酸生产分离装置的腐蚀研究

对醋酸分离装置的腐蚀进行了实验,研究了操作温度、氯离子浓度、醋酸浓度和甲酸浓度对腐蚀速率的影响规律。对实验结果进行了拟合与分析,得到了有关数学关联式,发现腐蚀速率与温度和介质浓度之间呈指数函数关系,且氯离子浓度和溶液温度对腐蚀速率的影响最大。从工艺角度讨论了减缓设备腐蚀的途径。     

精馏装置节能改造分析

本文就大庆化工有限公司甲醇分公司（简称甲醇分公司）一甲醇车间精馏装置优化改造进行分析。通过对加压塔、常压塔的优化调整,迎合了高端市场的需求,提高了市场竞争力,同时使能耗大幅度降低。     

精馏工序醋酸精制系统工艺改进

在醋酸乙烯精馏工序中，将醋酸精制系统中TQ-206釜排工艺进行改进，可获得较好的节能效果，改进前的工艺为进TQ-506提浓，改进后将其进CC-217，取代五塔工艺水。     

导向筛板塔在醋酸精馏中的研究与应用

导向筛板是一种近年来研究开发和应用较为成功的高效塔板,醋酸精馏是工业上一个重要的精馏过程.本文对醋酸分离的醋酸-水分离体系进行了相平衡的研究,对导向筛板上流体力学过程做了分析.将导向筛板塔板替换原普通筛板用于醋酸精馏后,可将醋酸的含量从97%～98%提高到99%以上,并将操作的回流比从55降低到40,其经济效益非常可观.在处理能力为9.5m3/h的醋酸回收塔中,采用导向筛板可取得230万元/年以上的经济效益.     

醋酸生产技术发展动向

对国外现有主要醋酸生产技术和正在开发的醋酸新工艺和新技术作了比较和评述 ,为我国醋酸工业发展提供借鉴。     

乙酸液相催化氧化动力学的研究

以乙酸钴、乙酸锰为催化剂，四溴乙烷为促进剂，在半间歇搅拌釜式钛材反应器中对乙酸的液相催化氧化动力学进行了研究，弄清了乙酸氧化损失的规律，提出了降低乙酸氧化速率的可行措施，得到了二氧化碳及乙酸甲酯的生成速率方程。     

PREPARATION OF ULTRAPURE PIVALIC ACID BY RECTIFICATION

A rectification method was developed for the purification of pivalic acid (PVA) on an experimental scale. Ultrapure PVA with a purity of 99.993% was prepared at a rate of 250 mL a week by multistep rectifications, a more convenient and much faster method than the traditional zone refining method. Typical operational conditions were: head pressure around 1 kPa, reboiler temperature 85°C, head vapor temperature 55°C, condenser temperature 36.5°C, and reflux ratio of 6:1. A formula was given to determine the purity of PVA based on the relationship of freezing point and purity. The freezing point of ultrapure PVA, which was obtained by measuring solidification temperature curve using an inner sheath method, is 35.912 ± 0.001°C.     

茂名石化乙苯/苯乙烯精馏塔的改造

茂名石化采用新型高效脉冲规整填料成功对原板波纹填料乙苯/苯乙烯精馏塔进行了改造,取得了很好的效果,塔顶苯乙烯质量分数由原来的5%降至1%以下,苯乙烯质量分数达到99.9%以上,乙苯质量分数小于500×10-6。     

导向浮阀塔板在醋酸生产中的应用

导向浮阀塔板是在F1型浮阀塔板的基础上开发成功的，较早应用于炼油装置的常减压蒸馏塔，在提高轻油的收率上获得了较大的经济效益，在化工产品的分离中应用较少。该项目在醋酸装置的精馏工序中，采用先进的导向浮阀塔板改造原有的F1型浮阀塔板，达到节能降耗，提高醋酸收率，增加醋酸产量，提高经济效益的目的。     

EFFECT OF ACETIC ACID ON CO2 CORROSION OF CARBON STEEL IN VAPOR-WATER TWO-PHASE HORIZONTAL FLOW

The effect of acetic acid on the corrosion behavior of X 65 and C 1018 carbon steel in vapor-water two-phase stratified flow (Vsg: 2 m/s; Vsl: 0.1 m/s) at 2 bars total pressure, 1.54 bars CO₂ partial pressure, pH 5.5, and 80°C was studied in a low pressure-high temperature multiphase flow horizontal loop using electrochemical and mass loss techniques. The liquid phase is composed of 1% NaCl aqueous solution containing different concentrations of acetic acid (500 to 5000 ppm total acetic acid), and the gas phase is composed of CO₂-acetic acid-water vapor mixture. The corrosion rates, on both the top and bottom of the line, increase with increase in acetic acid concentration, which was attributed to the contribution of hydrogen ions by the free acetic acid to the cathodic reaction. Partial coverage of the metal surface by FeCO₃ on both the top and bottom of the line is reported to be responsible for the observed localized corrosion. Surface analysis investigated with SEM and XRD is reported.

A vapor-liquid equilibrium model was developed for the system studied.     

ACETIC ACID AS AN OXYGEN CARRIER BETWEEN TWO PHASES FOR EPOXIDATION OF OLEIC ACID

Acetic acid was found to be an effective oxygen carrier for epoxidation of oleic acid. The reaction model of oleic acid epoxidation in the two-phase reaction system was systematically analyzed and the rate determining step was experimentally identified.

The results indicated that the rate of oxidation of the unsaturated acid was independent of the concentration of oleic acid and depended on the mixing rate and the rate of formation peracetic acid which in turn depended on the concentration of acetic acid, strength of acid catalyst and the oxygen source, hydrogen peroxide. In the region of reaction control, the rate equation of epoxidation was found to be

$

where k = 2.98 × 10^-2 M^-2 min^-1 at temperature of 35^°C.     

醋酸裂化生产醋酐工艺的技改

重点介绍了醋酐生产工艺的技术改造,通过改造,降低了消耗,提高了工葳物经济效益。     

DESIGN STRATEGY FOR ACETIC ACID RECOVERY

Acetic add is recovered from dilute aqueous solutions by extraction followed by azeotropic distillation. The heat required for distillation accounts for the major proportion of the cost of the process. Therefore, the proper selection of the entrainer is of great importance. In this paper, a procedure for preliminary entrainer selection is developed combining the well proved heuristic approaches and the latest developments for the synthesis phase based on residue curve maps and liquid-liquid equilibria plots. The energy requirements for the most promising entrainers are calculated using a commercial process simulator. It was found that methyl tert-butyl ether is a promising entrainer for the acetic acid dehydration process.