乙酸乙酯提浓塔的模拟与优化

通过选取合适的热力学模型,对乙酸乙酯提浓塔的操作进行模拟,与实际操作数据相比,误差在5%以内。对提浓塔的理论板数、回流量和进料位置等参数进行分析,得到了最优化的设计参数。     

ASPEN PLUS模拟与优化乙酸异丙酯提浓塔

以试验数据为基础．采用ASPENPLUS建立乙酸异丙酯提浓塔的模型,并考察进料板位置、回流比、塔板数等操作条件对目标产物的影响。结果表明,当进料板位置2-17、回流质量比1．5。2．5、理论塔板数为25块时,提浓塔塔釜采出的低沸物的质量分数在O．02％以下。塔釜采出乙酸异丙酯的质量分数可达到98．68％;尤其当回流比为1．5时,比原操作条件的塔釜热负荷减少24％。     

提浓塔灵敏板温控的改进

<正> 提浓塔是聚甲醛生产过程中的重要工序,提浓塔灵敏板温度又是该塔的主要控制指标,稳定温度对提高三聚甲醛精单体纯度(即提高聚甲醛产率)起着很大作用,达到一定的经济效果。为了获得高质量、高产量的聚甲醛产品,厂里多年来不断地作了各方面的改进,其中从温控方案的单回路调节、串级调节,直至采用了以灵敏板温度为主参数、回流量为副参数,以进料量为静态前馈,组成了前馈—串级调节系统,如图1所示:     

增设稀甲醛提浓塔

在生产1,4-丁二醇工艺中,增加稀甲醛提浓塔,可以解决原料甲醛浓度偏低,回收的稀甲酵量增多时,无法全部用于甲醛配制而制约产量的矛盾。     

乙炔提浓装置塔和换热设备优化

对原引进乙炔提浓技术经过消化、吸收并有所发展、创新,在对流程进行模拟的基础上,发现其中的谬误加以改正,并对局部流程进行优化,得出可靠的数据进行对塔和换热设备的优化核算。较多换热设备的尺寸更是有明显的减小,较大地节约了设备的成本,也更好地实现装置的安全、稳定、高效运行。     

提高醋酸提浓塔负荷的工艺分析

讨论了影响回收醋酸提浓塔(TQ506)塔负荷提高的诸因素,探讨用最佳工艺控制条件提高其负荷。     

盐析萃取应用于乙酸乙酯的提浓

采用盐析萃取应用于稀乙酸为原料制备己酸乙酯的提浓,对不同的萃剂比和含水不同的乙酸乙酯的盐析萃取效果进行了探讨,经盐析萃取可把乙酸乙酯含量提浓至96%以上.     

PVA装置中醋酸提浓塔D—436的现状分析

分析了ＰＶＡ装置醋酸提浓塔的现状，根据全塔的负荷性能和铜在醋酸中的腐蚀情况，可适当增加塔釜汽化量和增大回流比，对孔径增大１０％以上的塔板则予更换。     

循环提浓法回收净氨塔上层稀氨水

我厂3^#铜液再生系统净氨塔下层氨水循环提浓后回收使用,上层稀氨水由于浓度低,原设计就地排放。为解决环保问题,上层也采用了循环提浓法回收使用。具体办法是：将回收的氨水收集到氨水槽内冷却,再用泵打到上层循环使用。当氨水浓度达到2％时,送人净氨塔下层继续循环提浓至8．0％,送氨罐出售或解吸。     

Experimental and simulation of the reactive dividing wall column based on ethyl acetate synthesis

Reactive dividing wall column(RDWC) is a highly integrated unit which combines reaction distillation(RD) with dividing wall column separation technology into one shell, and it realized the chemical reaction and the separation of multiple product fractions simultaneously. In this paper, the reaction of esterification with acetic acid and ethanol to produce ethyl acetate was used as the research system, experiments and simulations of the RDWC were carried out. This system in the traditional process mostly used the homogeneous catalyst(e.g. sulfuric acid). However, in view of the corrosion of the equipment caused by the acidity of the catalyst, we used the heterogeneous catalysts – iron exchange resins – Amberlyst15 and proposed a novel catalyst loading method. Firstly,the reliability of the model of the simulation was verified by the experimental study on the change of liquid split ratio and reflux ratio. After that, the four-column model was established in Aspen Plus to analyze the effects of the amount of azeotropic agent, reflux ratio and acetic acid concentration. Finally, for a fair comparison, the economic analysis was conducted between traditional RD column and RDWC. The results showed that RDWC can save34.7% of total operating costs and 18.5% of TAC.     

Reactive dividing-wall column for the co-production of ethyl acetate and n-butyl acetate

Reactive dividing-wall column (RDWC) technology plays a critical role in the energy saving and high efficiency of chemical process. In this article, the process of co-producing ethyl acetate (EA) and n-butyl acetate (BA) with RDWC was studied. BA was not only the product, but also acted as entrainer to remove the water generated by the two esterification reactions. Experiments and simulations of the co-production process were carried out. It was found that the experimental results were in good agreement with the simulation results. Two kinds of RDWC structures (RDWC-FC and RDWC-RS) were proposed, and the co-production process operating parameters of the two types of RDWC were optimized by Aspen Plus respectively. The optimal operating parameters of the RDWC-FC were determined as follows: 0.6 of the reflux ratio of aqueous phase (RR), 0.66 of the vapor split (R_V) and 0.51 of the liquid split (R_L). And the optimal operating parameters of the RDWC-RS were shown as follows: RR was 0.295 and R_V was 0.61. Furthermore, the energy saving analysis of the co-production process was based on the annual output of 10000 tons of EA, compared with the traditional reaction distillation (RD) to prepare EA and BA, the reboiler duty of the RDWC-FC column could save 20.4%, TAC saving 23.6%; RDWC-RS reboiler energy consumption could save 17.0%, TAC 22.2%.     

乙酸乙酯脱水精馏塔的模拟与优化

通过选择合适的热力学方法,采用Aspen Plus流程模拟软件对乙酸乙酯生产过程中脱水精馏系统进行了流程模拟和工艺参数优化,考察了进料位置、分相器加水量、再沸器热负荷等参数对乙酸乙酯产品质量的影响,产品质量达到GB/T3728—2007优等品标准,确定了最优的工艺条件,为工程设计和项目开车提供了理论指导。     

Kinetics modelling of ethyl acetate oxidation in flame conditions

To optimize the good working of the common thermal oxidizers, a better understanding of the high temperature oxidation kinetic of volatile organic compounds (VOCs) in flame conditions is needed. So the experimental study of Ethyl Acetate (EA) oxidation in CH₄/EA/O₂/N₂ low pressure flames has been investigated. Molecular species concentration profiles of CH₄, O₂, CO, CO₂, H₂O, C₂H₂, C₂H₄, C₂H₆, C₃H₆, C₃H₈, EA, CH₃OH, C₂H₅OH, CH₃CHO, C₂H₅CHO, CH₃COCH₃, CH₃OCH₃, CH₃COOCHCH₂ and CH₃COOH have been obtained by coupling microprobe sampling with gas chromatography-mass spectrometry (GC/MS) analysis. A detailed kinetic mechanism has been developed to model the EA oxidation in these conditions. The kinetic scheme includes 23 oxygenated species involved in 142 reversible reactions. It takes into account the first steps of the EA oxidation and the oxidation processes of all the measured oxygenated intermediate compounds. The proposed mechanism globally well predicts the experimental results obtained in the methane/air flames even if some discrepancies are pointed out. Sensitivity analysis allows the determination of the main reactional pathways involved in the thermal degradation of EA.     

Experiments and dynamic modeling of a reactive distillation column for the production of ethyl acetate by considering the heterogeneous catalyst pilot complexities

Great effort has been applied to model and simulate the dynamic behavior of the reactive distillation as a successful process intensification example. However, very little experimental work has been carried out in transient conditions. The work presents a series of experiments for the production of ethyl acetate from esterification of acetic acid and ethanol in a reactive distillation pilot column. The steady-state approach performed experiments with both excess of alcohol and stoichiometric feed configuration. Predicted and measured results show good agreement and reveal a strong dependency of the structured packing catalyst activity on the pilot geometry and its operating conditions. The transient process behavior of the heterogeneously catalyzed system was deeply investigated and continuous and dynamic data were collected for an equilibrium model validation, after different perturbations on parameters. The experimental validation is shown to be essential to provide realistic hydrodynamic parameters, to understand the sensitive parameters such as heat losses and to adapt values for the catalyst holdup as a function of the system.     

Catalytic oxidation of ethyl acetate over a cesium modified cryptomelane catalyst

Cryptomelane-type manganese oxide was synthesized by redox reaction under acid and reflux conditions. Cesium was incorporated into the tunnel structure by the ion-exchange technique. The catalytic oxidation of ethyl acetate in low concentration (1600 ppmv) was used to test the performance of the catalysts prepared. The presence of small amounts of cesium was found to improve the catalytic performance of cryptomelane. This behaviour was correlated with the basic properties of the catalyst. Temperature programmed experiments, and tests without oxygen in the feed, suggest that lattice oxygen atoms can react with ethyl acetate at low temperatures and are involved in the mechanism of ethyl acetate oxidation.     

反应精馏隔壁塔内合成乙酸甲酯的模拟

提出了一种应用反应精馏隔壁塔合成乙酸甲酯的新工艺流程,采用反应精馏隔壁塔替代常规反应精馏流程中的反应精馏塔及甲醇回收塔。利用Aspen Plus模拟软件,对反应精馏隔壁塔及常规流程进行了模拟,比较分析了两种流程塔内液相组成分布,并分析了塔顶回流比与气相分配比对反应精馏隔壁塔的影响。结果显示新流程可以节能11.9%,并能降低设备投资费用和操作费用。     

SO2 promoted oxidation of ethyl acetate, ethanol and propane

The effect of SO₂ addition on the oxidation of ethyl acetate, ethanol, propane and propene, over Pt/γ-Al₂O₃ and Pt/SiO₂ has been investigated. The reactants (300–800 vol. ppm) were mixed with air and led through the catalyst bed. The conversions below and above light-off were recorded both in the absence and in the presence of 1–100 vol. ppm SO₂. For the alumina-supported catalyst, the conversion of ethyl acetate, ethanol and propane was promoted by the addition of SO₂, while the conversion of propene was inhibited. The effect of SO₂ was reversible, i.e. the conversion of the reactants returned towards the initial values when SO₂ was turned off. However, this recovery was quite slow. The oxidation of propane was inhibited by water, both in absence and presence of SO₂. For the silica-supported catalyst no significant effect of SO₂ could be observed on the conversion of ethyl acetate, ethanol or propane, whereas the conversion of propene was inhibited by the presence of SO₂. In situ FTIR measurements revealed the presence of surface sulphates on the Pt/γ-Al₂O₃ catalyst with and after SO₂ addition. It is proposed that these sulphate groups enhance the oxidation of propane, ethyl acetate and ethanol by creating additional reaction pathways to Pt on the surface of the Pt/γ-Al₂O₃ catalyst.     

磺酸型固体催化剂催化合成乙酸乙酯

苯乙烯/丙烯磺酸共聚物(St-c-AS)作为一种高效、无污染、可重复利用的固体酸催化剂被用于乙酸和乙醇的酯化反应中。实验结果表明,该催化剂具有较高的催化活性,催化剂不需分离可重复使用10次,酯化产率达到90%以上。与传统的硫酸催化剂相比,St-c-AS为催化剂所得的产品无需除酸,后处理简单,对环境无污染,是一条合成乙酸乙酯的绿色途径。     

Supported catalytic packing prepared from ceramic packing for reactive distillation of ethyl acetate

In this work, a strategy of “etching-modification filling-graft copolymerization” was proposed to load the acidic ionic polyionic liquid on the smooth ceramic surface. In this way, commercial ceramic Raschig rings were successfully transformed into the supported catalytic packing for the reactive distillation, and were further evaluated with esterification reaction of ethyl acetate by means of the fully mixed reactor, the ultrasonic destruction, the cyclic catalysis reaction and the lab-scale distillation column experiment. This catalyst coating has good adhesion with the substrate. It can withstand 24 h of ultrasound damage and shows good stability in three cycle catalytic experiments. This kind of coated catalyst has better catalytic activity than the commercial Amberlyst 15 dry. In the lab-scale reaction distillation, the supported catalyst Raschig ring can achieve a higher conversion in comparison with the tea bag catalytic packing of Amberlyst 15 dry under some conditions.