带侧线反应精馏-渗透汽化生产乙酸乙酯集成过程模拟与分析

针对乙酸酯化法生产乙酸乙酯分离过程复杂、能耗大的缺点,提出了一种带侧线反应精馏-渗透汽化(RDPV)集成过程。通过反应精馏塔侧线采出和渗透汽化膜组件及时移出水分,促进酯化反应向正反应方向进行,在达到乙酸高转化率的同时使乙酸乙酯产品达到高纯度。研究了反应精馏塔侧线采出位置、采出比、反应段塔板数、精馏段塔板数以及膜组件个数等对年度总成本(TAC)的影响,获得了TAC达到最小的过程参数。与传统双塔精馏分离过程对比,RD-PV集成过程节省能耗26.6%,但膜材料价格对RD-PV集成过程的TAC有较大影响,随着渗透汽化技术的成熟,当膜材料价格低于1913 CNY·m-2时,RD-PV集成过程在经济上占据优势。     

带多台侧反应器的间歇反应精馏生产氯化苄非稳态模拟与过程设计

建立了带多台侧反应器的间歇反应精馏过程,采用Aspen Plus模拟软件构建该过程的非稳态模拟方法。以甲苯氯化生产氯化苄为对象,研究了侧反应器台数、侧线采出率和采出位置、氯气分配、反应精馏时间及再沸器蒸发量等设计参数对间歇反应精馏过程的影响规律。模拟结果表明反应能力和分离达到最佳匹配的最优设计参数为:精馏塔塔板数8块、侧反应器2台、氯气分配7:3、从第3块塔板侧线采出、采出率85%、再沸器蒸发量25 kmol?h?1。在此结构参数和操作条件下完成50 kmol甲苯氯化所需时间为9 h,甲苯的转化率和氯化苄的选择性均可达到98.0%以上。     

分隔壁精馏塔在乙苯装置分离工艺中的应用及能耗分析

采用分隔壁精馏塔(DWC)精馏技术对乙苯装置分离工艺进行了改进,将传统分离工艺中的苯塔和乙苯塔集成为1个分隔壁精馏塔,不仅可以实现烷基化产物的分离,而且可以有效降低装置能耗。使用Aspen Plus流程模拟软件对基于DWC的新分离工艺进行了全流程模拟,并对传统分离工艺和分隔壁塔新工艺的能耗进行了对比。计算结果表明,分隔壁塔总塔板数为58块,分隔壁在第15块到第40块塔板之间,进料位置在第24块塔板,侧线抽出苯位置在第4块板,侧线采出乙苯产品位置在第26块板,塔顶回流比为2.3。侧线抽出苯和塔顶采出苯的质量分数分别为99.44%和99.20%,中间侧线采出乙苯的质量分数为99.94%,塔釜物料中乙苯的质量分数为0.06%。分隔壁精馏塔实现了苯、乙苯和多乙苯物系的清晰分离。计算结果还表明,采用DWC分离工艺的能耗比传统的顺序分离工艺降低约41%。     

不同温度反应与精馏集成生产醋酸叔丁酯的过程模拟

针对醋酸与异丁烯加成酯化可逆反应温度低、精馏分离温度高的特点,采用带侧反应器的反应精馏集成过程(SRC)建立了低温反应与高温精馏集成的醋酸叔丁酯生产新工艺。固定塔釜上升汽化量100 kmol·h^-1,规定新鲜醋酸进料的转化率达到99.9%、醋酸叔丁酯选择性达到97.0%,采用过程模拟考察了进入侧反应器的精馏塔采出量、精馏段塔板数、侧反应器进出口间隔塔板数和侧反应器台数等参数对合成醋酸叔丁酯的SRC过程的影响。模拟结果表明,醋酸与异丁烯加成酯化生产醋酸叔丁酯的SRC过程中只有反应能力与分离能力达到最佳匹配才能使单位产品的生产成本最小。研究结果为醋酸叔丁酯生产新工艺的放大设计与优化奠定了基础。     

“背包式”反应精馏生产丙烯酸叔丁酯工艺

针对丙烯酸与异丁烯酯化加成反应具有反应温度较低、精馏温度较高的特点,文中设计了加压较低温度反应-减压较高温度精馏集成的"背包式"反应精馏生产丙烯酸叔丁酯新工艺。以年度总成本(TAC)为目标,采用序贯优化法对过程工艺参数进行优化设计。规定新鲜丙烯酸进料量为10 kmol/h,塔顶产品中丙烯酸叔丁酯质量分数不低于98%,新鲜丙烯酸转化率达到99%,得到最佳过程配置参数和操作参数:侧反应器台数为2,进入侧反应器1(R1)的侧线采出量为10 kmol/h,进入侧反应器2(R2)的侧线采出量为5 kmol/h,以及催化剂总装填量为200 kg且分配比为0.7/0.3,总塔板数为28块(包括冷凝器和再沸器),精馏段塔板数为15块,侧反应器进出口间隔塔板数为5,回流比为0.64,此时TAC最小为1.439×10~6元/a。     

热耦合精馏醇醚共沸混合物的设计与优化

为了获得节能经济的分离仲丁醇(SBOH)-仲丁氧基甲氧基甲烷(SMMB)-二仲丁氧基甲烷(DSBM)共沸物系的精馏工艺,文中基于热耦合精馏原理及萃取精馏原理构建了6种分离序列,以TAC(年总成本费用)最小为优化目标,采用序贯迭代优化方法考察理论塔板数、回流比、进料位置、侧线采出位置等设计参数对节能、投资的影响。研究结果表明:分隔壁侧线精馏塔(DWC-SR)与萃取隔壁精馏塔(EDWC)组合分离序列,节能与降低成本效果显著。与其他5种分离序列比,再沸器热负荷分别减少3.34%,26.44%,0.34%,3.66%,26.63%,TAC分别节约2.19%,23.77%,1.67%,3.78%,24.74%。     

芳烃生产工艺改进与经济性分析

围绕芳烃生产过程节能降耗需求,采用Aspen模拟平台建立了二甲苯精馏单元、吸附分离单元、异构化单元机理模型,并以此为基础进行模拟仿真,提出了从二甲苯精馏塔侧线采出OX的工艺改进方案。在工业操作条件下,考察了二甲苯精馏塔不同塔板位置对侧线OX最大抽出量的影响规律,并获得最优采出位置和采出量;结合实际工业对象,分析了侧线抽出方案对吸附分离和异构化单元能耗的联动效应,并对芳烃全流程生产的经济性进行测算。结果表明,侧线抽出可直接减少13. 25 t/h的大循环量,显著降低吸附分离单元能耗,同时也重新配置了精馏单元芳烃资源,降低了精馏单元内部能耗,为芳烃生产节能降耗提供了有益思路。     

乳酸过量进料反应精馏合成乳酸甲酯研究

针对乳酸与甲醇酯化反应体系中乳酸和甲醇的沸点分别为最高沸点与最低沸点,属于反应精馏设计中最劣沸点序列,导致乳酸甲酯反应精馏过程反应段效率低下的问题,设计了乳酸过量进料的反应精馏合成乳酸甲酯工艺。以年度总费用(TAC)为目标,采用序贯优化法对过程工艺参数进行优化设计,结果表明当乳酸过量比为1.3、反应精馏塔反应塔板数为7块、提馏段塔板数为16块(包括塔底再沸器)时,过程年度总费用达到最小为3.05×10~6 CNY×a~(-1)。相比于等比进料合成乳酸甲酯反应精馏工艺,乳酸过量进料反应精馏工艺能耗降低70.4%,TAC减小51.2%,更具经济效益。     

一种渗透汽化-加压精馏集成分离碳酸二甲酯和甲醇的工艺

正本发明提供了一种渗透汽化-加压精馏集成分离碳酸二甲酯和甲醇的工艺,其特征在于反应精馏塔得到的碳酸二甲酯和甲醇的共沸液经过渗透汽化膜系统时,渗透汽化膜有效突破了甲醇-碳酸二甲酯共沸瓶颈,碳酸二甲酯低浓度侧料液返回至反应精馏塔进行循环分离,碳酸二甲酯高浓度侧料液输送至加压精馏塔,经加压精馏塔分离后塔釜得到质量纯度为99.6%以上的碳酸二甲酯产品,塔顶得到甲醇含量较高的碳酸二甲酯和甲醇混合液,也返回到反应精馏塔中,进入下一次循环分离。本发明工艺     

侧线精馏塔高效分离二甲醚-甲醇-水的稳态模拟与动态控制研究

利用Aspen Plus模拟软件对二甲醚-甲醇-水分离过程中的侧线精馏塔进行稳态研究,在设计规定下对侧线精馏塔的设计与操作参数进行确定与优化,最终获得侧线精馏塔的理论板数为52块,最佳进料位置为第32块塔板,侧线出料位置为第12块塔板,回流比为41,灵敏板为第3块塔板。通过Aspen Dynamics考察了进料流量扰动(±5%)和进料组成扰动(±5%)的工况下,侧线精馏塔采出的产品纯度、灵敏板温度、采出量、再沸器热负荷等参数均可达到平衡,恢复至设定值,模拟结果说明侧线精馏塔的控制方案有效可行。     

中空纤维渗透汽化复合膜及组件研究进展

中空纤维渗透汽化膜组件具有器件小型化及成本较低等方面的优势,其工业应用潜力巨大。本文介绍了中空纤维渗透汽化复合膜及组件的研究进展,阐述了膜材料、成膜方法以及组件结构参数等对组件渗透汽化性能的影响,并对中空纤维渗透汽化膜组件的中试研究进行了总结。通过组件放大及中试研究发现,中空纤维渗透汽化膜组件的装填密度、长度以及抽吸方式均会影响其下游侧的真空度,从而影响其渗透汽化性能。膜材料的分子设计、组件的结构参数优化以及耐溶剂耐高温封装将是中空纤维渗透汽化膜组件未来工业放大过程中的关键环节。     

PDMS/ZSM-5膜的制备及渗透汽化分离水中乙酸正丁酯和乙酸乙酯

为探究出适合分离水中的乙酸正丁酯和乙酸乙酯的新型渗透汽化膜材料，选用沸石ZSM-5 对聚二甲基硅氧烷(PDMS)材料进行填充改性，以聚偏氟乙烯(PVDF)为支撑层，采用刮涂法制备PDMS/ZSM-5/PVDF复合膜渗透汽化分离水中的乙酸正丁酯和乙酸乙酯。采用SEM、接触角测量仪、FTIR、TGA和XRD等对膜材料物理化学性能进行表征，考察了膜材料的溶胀行为及渗透汽化性能。结果表明，ZSM-5在 PDMS 膜中分散均匀，且没有发生化学作用，并提高了膜材料的疏水性和热稳定性。随着ZSM-5添加量的增加，膜在乙酸正丁酯和乙酸乙酯的溶胀度和待分离组分在膜材料中的扩散速率不断增加。随着进料浓度和温度的增加，渗透通量不断增大，分离因子先增大后减小。随着ZSM-5在PDMS/ZSM-5/PVDF复合膜中含量的增加，总渗透通量增加，而分离因子呈现先增加后减小的趋势。当添加量为10%（质量）时，分离因子达到最大值。对于乙酸正丁酯/水体系，渗透通量和分离因子最大值分别为319 g·m ^-2·h ^-1和131；而对于乙酸乙酯/水体系，渗透通量和分离因子最大值分别为1385 g·m ^-2·h ^-1和121。     

用于生产TAEE的反应精馏和全蒸发的混合过程

In this study, a reactive distillation column in which chemical reaction and separation occur simultaneously is applied for the synthesis of tert-amyl ethyl ether （TAEE） from ethanol （EtOH） and tert-amyl alcohol （TAA）. Pervaporation, an efficient membrane separation technique, is integrated with the reactive distillation for enhancing the efficiency of TAEE production. A user-defined Fortran subroutine of a pervaporation unit is developed, allowing the design and simulation of the hybrid process of reactive distillation and pervaporation in Aspen Plus simulator. The performance of such a hybrid process is analyzed and the results indicate that the integration of the reactive distillation with the pervaporation increases the conversion of TAA and the purity of TAEE product, compared with the conventional reactive distillation.     

Energy-Efficient Process with a Decanter to Separate Toluene-Methanol-Water Ternary Azeotropic Mixtures

An extractive distillation process with two columns and a decanter was proposed to separate ternary toluene-methanol-water azeotropic mixtures in a previous study. Based on this process, six processes were established to explore further energy-efficient schemes to separate the ternary azeotropic system. The optimal parameters of the process were determined in terms of the minimum total annual cost (TAC). The processes with heat integration perform better than those with a side stream or thermal coupling in terms of energy savings and TAC reduction. A process in which both the feed stream of the extractive distillation column and the entrainer recovery column are preheated by the entrainer recycle stream can reduce energy consumption by up to 27.69 % and TAC by 21.36 %.     

High‐performance PDMS membranes for pervaporative removal of VOCs from water: The role of alkyl grafting

To improve the pervaporation performance of PDMS membrane, alkyl groups with different chain length were grafted into PDMS matrix. The prepared membranes were characterized by ATR‐IR, DSC, TGA, PALS, and tensile testing. The effects of alkyl grafting on pervaporation performance of PDMS membrane were investigated in separation of ethyl acetate/water mixture. Experimental results show that the separation factor of PDMS membrane is largely improved by alkyl grafting because of the enhanced preferential sorption of ethyl acetate, and this improvement depends on alkyl grafting ratio and alkyl chain length. The total flux of PDMS membrane reduces after alkyl grafting owing to the decreased free volume. When grafting ratio is above 6.9%, membrane grafted with shorter alkyl groups is preferred for pervaporation. The best pervaporation performance is achieved by 9% octyl grafted PDMS membranes with a separation factor of 592 and a total flux of 188 gm^?2 h^?1 in separation of 1% ethyl acetate/water mixture at 40 °C. Moreover, this octyl grafted PDMS membrane also exhibits excellent separation performance in removal of butyl acetate, methyl‐tert‐butyl ether, and n‐butanol from water. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43700.     

MTBE-C_4-甲醇的蒸馏-渗透汽化集成分离过程设计

<正>国内现有甲基叔丁基醚（MTBE）生产装置20余套,年生产能力约50万t,分化工及炼油型2种工艺路线。1994年以前建成的大多采用筒式反应器技术,1994年以后则以齐鲁石化公司研究院开发的预反应加催化蒸馏技术为多。无论是化工型还是炼油型工艺路线,无论是采用筒式反应器还是催化蒸馏技术,最后均需用水洗工艺将C_4中的甲醇脱除,此工艺设备投资大、操作繁、耗能高。渗透汽化（PVAP）膜分离是近十几年来颇受注目的一项新型膜分离技术,具有一次性分离度高、设备简单、无污染、低能耗等优点,对某些用常规分     

A generalized methodology for optimal configurations of hybrid distillation-pervaporation processes

The aim of this work is to illustrate the structural and parametric optimization of continuous hybrid distillation-pervaporation process with different configurations such as series, parallel, and series-parallel arrangement of pervaporation modules in the pervaporation network, and to propose a generalized methodology for difficult separations. A superstructure representation of hybrid process is considered and the process is modeled and optimized using an MINLP approach. The optimization strategy is to obtain the desired degree of either the retentate or the distillate purity without violating the composition constraints of products and heat exchange policy which minimizes the required membrane area by increasing the flux through the membrane. The structural and operating parameters such as number of trays required, feed tray location, reflux ratio, retentate recycle location, permeate recycle location, membrane feed location, number of pervaporation modules required, target composition (which is directly related to membrane area), and membrane selectivity are optimized for each configuration by minimizing the total annual cost (TAC) for the separation system. The optimization studies have been carried out with General Algebraic Modeling System software (GAMS/SBB/CONOPT) and the results of different configurations have been compared on the basis of TAC required for the separation. A total of three industrial case studies have been dealt with. The separation of isopropanol-water as an azeotropic mixture, propylene-propane as a close boiling mixture (system with a low relative volatility) and acetone-water as a tangent pinch mixture have been studied as representative examples.     

Esterification of Acetic Acid and Ethanol in a Flow‐Through Membrane Reactor Coupled with Pervaporation

The esterification of acetic acid is an important industrial process for the synthesis of ethyl acetate. A membrane reactor with a sulfonated polyethersulfone/polyethersulfone/non‐woven fabrics composite catalytic coupled with a poly(vinyl alcohol) pervaporation membrane was applied in continuous esterification of ethanol with acetic acid in a flow‐through mode. High equilibrium conversion was obtained for esterification in a closed‐loop mode. For the pervaporation‐assisted esterification in this mode, the experimental conversion was very close to the theoretical value.     

Transport of Small Molecules through Polyphenylene Oxide Membranes Modified by Fullerene

Abstract

Homogeneous membranes based on fullerene‐polyphenylene oxide compositions containing up to 2 wt% fullerene C₆₀ were prepared. The effect of fullerene addition on PPO transport properties was studied in gas separation and pervaporation processes. Permeability coefficients of H₂, O₂, N₂, CH₄, and CO₂ were measured; a correlation between gas transport properties and membrane free volume was established. Pervaporation properties were studied for the system with ethyl acetate synthesis reaction: quaternary system ethanol—acetic acid—water—ethyl acetate and some constituent binary and ternary mixtures. Pervaporation in binary systems, ethanol–water and ethyl acetate–water was considered with the use of the data on sorption capacities and interaction parameters. In pervaporation of a quaternary reacting mixture, the permeate containing essentially ethyl acetate was obtained. Results show that membranes with fullerene additives exhibit improved transport properties.     

基于MVR热泵精馏的混合醇热集成分离工艺

机械蒸汽再压缩(MVR)热泵技术是把低品位的蒸汽通过压缩转变为高品位的蒸汽,循环用于热源的供热以减少能耗。而热集成技术则是合理的匹配冷热物流的换热,以提高物流的有效能利用率。鉴于精馏过程的高能耗和低热力学效率,本文以四元混合醇的分离为研究对象,把基于MVR热泵技术的热集成精馏工艺应用于该体系的分离,提出并研究了该体系带热集成与不带热集成各种MVR精馏工艺;以能耗和年总费用(TAC)为评价指标,采用Aspen Plus 软件对各分离工艺进行模拟与优化,确定各分离工艺的操作参数与设备参数。研究结果表明,与常规顺序分离工艺相比,MVR精馏工艺节约能耗50%以上,节约年总费用约61%。带热集成MVR精馏工艺与不带热集成MVR精馏工艺相比,在能耗和年总费用方面,优势相当,但前者热力学效率提高了约9.5%。