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使用Aspen Plus V8.4对环己烷/异丁醇共沸物系的共沸精馏和变压精馏流程进行了模拟与优化。选用乙醇为共沸剂,分别建立了共沸精馏和变压精馏的全局流程,研究了原料进料位置、回流比和共沸剂进料位置对分离效率的影响,得到了2种分离方法的操作参数和工艺参数。结果表明,共沸精馏流程的原料最佳进料位置为14块板,最小回流比为3.00,共沸剂的最佳进料位置为第一块板。变压精馏流程中减压塔最佳进料位置为第8块板,总理论板数为10块板,最小回流比为1.144,最小理论板数为8块板。同时,对2个工艺流程进行了经济分析。结果表明,变压精馏的年总费用比共沸精馏下降了62.7%。 相似文献
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《精细化工原料及中间体》2016,(9)
正一种变压热耦合精馏分离甲缩醛与甲醇的工艺是甲醇与甲缩醛混合溶液从低压精馏塔上部进入进入塔内,循环物流从塔下部进入,甲缩醛甲醇共沸物蒸汽从塔顶流出,经冷凝后一部分回流至塔内作为回流液,另一部分作为高压精馏塔进料采出,塔釜得到纯净甲醇;在高压精馏塔塔顶得到甲缩醛甲醇共沸物蒸汽,该蒸汽去低压精馏塔再沸器冷凝后一部分回流至高压精馏塔作为回流液,另一部分作为循环物流返回至低压精馏塔,高压精馏塔塔釜得到纯净甲缩醛。本发明具有分离过程简单,成本低,分离 相似文献
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以洗油为原料,通过精馏-共沸精馏法,研究了喹啉的分离精制。首先精馏洗油,切取不同温度段的馏分,然后分别与共沸剂乙二醇进行共沸精馏试验;在共沸精馏中,通过改变馏分与共沸剂的质量比和回流比,考察了不同条件对喹啉纯度的影响。结果表明:①精馏洗油切取喹啉馏分的较佳条件为:回流比为10∶1,切取温度范围为220~230℃;②共沸精馏的较佳条件为:回流比为10∶1,喹啉馏分与共沸剂的质量比为1∶2.4,切取温度范围为188.4~188.8℃,喹啉的纯度可达98.5%。该方法具有操作简单、步骤少、纯度高、无污染的特点。 相似文献
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《精细化工原料及中间体》2018,(6)
正本发明为一种间歇共沸精馏法分离乙二醇单甲醚和水的工艺,该工艺包括1)共沸精馏脱水:按质量比原料:共沸剂=(4~8):1,将原料和共沸剂加入精馏塔1的塔釜中,操作回流比为1~2.5,当精馏塔1塔顶温度T1=89℃~90℃,共沸精馏脱水结束;2)乙二醇单甲醚产品精制:继续精馏,操作回流比1~2.5,当精馏塔塔顶温度T1=124.6℃时,釜液为乙二醇单甲醚成品;3)回收共沸剂:塔釜采用再沸器2进行加 相似文献
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甲醇-碳酸二甲酯二元共沸物的分离 总被引:1,自引:0,他引:1
分别用共沸精馏法和萃取精馏法对甲醇一碳酸二甲酯(DMC)二元共沸体系进行了分离,通过正交实验分别得到了最佳分离工艺条件。实验结果表明,共沸精馏法的最佳分离工艺条件:共沸剂正己烷用量为总质量(共沸剂+甲醇)的76%,回流比控制在3:1,馏出速率为6mL/min;萃取精馏法的分离最佳工艺条件:以糠醛为萃取剂,回流比控制在3:1,萃取剂滴加速率为3mL/min,萃取剂配比为4:1。并分别从装置和纯度方面对两种方法进行比较,结果表明萃取精馏法占优。 相似文献
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乙酸甲酯和甲醇共沸物对压力变化敏感,因此采用变压精馏工艺对共沸物进行高效分离。低压塔和高压塔压力分别设置为101.325 kPa和810.600 kPa。基于相图分析,确定了精馏序列和工艺流程。以年度总费用(TAC)最小为原则,优化了进料位置、回流比、塔板数等设计变量,确定了最佳工艺参数。工艺优化完成后,通过调节双塔的回流比,对高压塔的冷凝器和低压塔的再沸器进行了完全热集成。由结果可知:在低压塔回流比为0.9,高压塔回流比为2.07时,完全热集成变压精馏工艺的TAC最小。相比无热集成的变压精馏工艺,完全热集成工艺的设备投资和能耗费用均明显降低,最终TAC费用节约31.40%,在经济上更合理,也为类似的共沸物分离工艺提供了一定的技术参考。 相似文献
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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。 相似文献
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Leland M Vane Franklin R Alvarez 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(9):1275-1287
BACKGROUND: Energy efficient alternatives to distillation for alcohol recovery from dilute solution are needed to improve biofuel sustainability. A process integrating steam stripping with a vapor compression step and a vapor permeation membrane separation step is proposed. The objective of this work is to estimate the energy and process costs required to make a fuel grade ethanol (0.5 wt% water) from 1 and 5 wt% ethanol aqueous streams using the proposed process. RESULTS: Using process simulation and spreadsheeting software, the proposed membrane‐assisted vapor stripping process was estimated to require as little as 8.9 MJ of fuel‐equivalent energy per kg of fuel grade ethanol recovered from a 1 wt% ethanol feed stream, 2.5 MJ kg?1 for a 5 wt% ethanol solution. This represents an energy saving of at least 43% relative to standard distillation producing azeotropic ethanol (6 wt% water). Process costs were also found to be lower than for distillation at the 3.0 × 106 kg‐ethanol year?1 scale modeled. CONCLUSION: In this hybrid system, the stripping column provides high ethanol recoveries and low effluent concentrations while the vapor compression‐membrane component enables the efficient recovery of latent and sensible heat from both the retentate and permeate streams from the membrane system. Published in 2008 by John Wiley & Sons, Ltd. 相似文献
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间歇共沸精馏法回收制药废液中的乙醇 总被引:1,自引:0,他引:1
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. 相似文献
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Ethanol is a biofuel, produced through the fermentation of sugars derived from biomass. Its usefulness as a fuel is limited by the energy intensive nature of the ethanol separation process. The ethanol recovery process is inefficient due to the dilute nature of the fermentation product and the presence of the ethanol?water azeotrope. This investigation presents a new hybrid separation process for energy efficient ethanol recovery. The new process is a hybrid of distillation and pervaporation. However, as opposed to most other hybrid processes, the distillation and pervaporation processes are combined into single unit. An overview of the proposed system was provided and differences to the conventional separation process were highlighted. A mathematical model was derived to explain the transport phenomena occurring in the hybrid process. The model was then used to compare the process to distillation. It was shown that the hybrid process is capable of breaking the ethanol-water azeotrope. It was also demonstrated that the pervaporation process, which is associated with both material and energy transfer, induces partial condensation of the vapor and thereby affects the efficiency of vapor?liquid contacting. Simulations were presented to show the impact of reflux ratio and pervaporation flux on the performance of the process. 相似文献
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Antonio Meirelles Siegfried Weiss Herbert Herfurth 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1992,53(2):181-188
Experiments and process simulation enable favourable operating conditions to be determined for the extractive distillation of ethanol—water, with ethylene glycol as a solvent. The solvent molar rate to feed molar rate ratio S/F = 0·6 and the reflux ratio R = 0·5 were determined in order to achieve at least 99·5 mole % purity of ethanol. Other parameters examined include feed concentration, purity of solvent, and number of plates. Extractive distillation can be used to achieve high purity of ethanol at low energy consumption and under simple operating conditions. 相似文献
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《分离科学与技术》2012,47(10):1518-1528
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. 相似文献
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《分离科学与技术》2012,47(8):1365-1375
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. 相似文献