隔壁精馏塔应用于空气分离的研究

以空气分离为例,考察了将隔壁精馏塔应用于空气分离的建模与基于年总成本的优化过程。首先对于空分上塔的氩浓度剖面进行了分析,提出了两种应用隔壁精馏塔的可能性,最终选择了带侧线精馏段的隔壁塔。然后考察了空分隔壁精馏塔上塔的各个结构参数与操作参数对其年总成本的影响,在保证产品质量的基础上得到优化的结构参数与操作参数。研究表明,与传统流程相比,将隔壁精馏塔应用于空气分离过程可使年总成本减少7.69%。     

石脑油分离隔壁塔综合性能模拟研究

在流程模拟软件Aspen Plus中建立石脑油分离隔壁塔模拟流程,利用传统石脑油分离两塔流程工艺参数作为初值,使用单因素变量法对隔壁塔工艺参数进行调整和优化。研究隔壁塔内主要操作和结构参数,如隔板位置、气液分配比、公共精馏段塔板数和提馏段塔板数对于隔壁塔能耗的影响。同时,研究了进料组成变化对于隔壁塔性能的影响。     

分隔壁萃取精馏塔分离醋酸水溶液的模拟

提出了一种新的单塔萃取精馏精制醋酸水溶液的新工艺,该工艺采用分隔壁萃取精馏塔(DWC-E)替代常规萃取精馏流程的萃取精馏塔及溶剂回收塔,不仅节省了设备投资,而且降低了总能耗。利用Aspen Plus模拟软件,对DWC-E塔及常规萃取流程进行了模拟。DWC-E塔的操作条件:塔板数40块,侧线精馏段的板数10块,回流比2,溶剂摩尔比2.5,在此条件下,比较了常规萃取精馏流程与分隔壁精馏塔内温度、液相组成及汽液相流量的变化。结果表明,DWC-E塔比常规的2塔萃取精馏流程节能23.91%。     

隔壁精馏塔的热力学等效模拟研究

对隔壁精馏塔的热力学等效模拟进行研究。隔壁精馏塔和全热耦合精馏Petlyuk塔在热力学上等效,通过三塔模型对隔壁精馏塔进行简捷计算,计算结果作为初值,利用Aspen Plus软件中Multifrac-Petlyuk模块对DWC进行严格模拟计算,并利用灵敏度分析模块,分别对各参数进行优化,确定最佳的塔参数及操作条件。以甲醇-乙醇-正丙醇三元体系为例,隔壁精馏塔的热力学等效模拟结果为:主塔塔板数62,预分塔塔板数30,互连位置N1为20,N2为50,基于预分塔的进料位置在第10块板,基于主塔的侧线出料位置为第38块板,主塔回流比为8,互连物流qL,12=340 kmol/h,qV,12=880 kmol/h,在此参数下,可以得到质量分数99.2%的甲醇、97.9%的乙醇和97.3%的正丙醇,满足分离要求。     

隔壁塔流程模拟及节能效益的研究

隔壁塔技术是一种效果优良的过程强化与精馏节能技术。具有特殊结构的隔壁塔相比常规精馏塔具有较高的热力学效率。对于相同的分离任务,隔壁塔所需的能耗较低,同时隔壁塔技术的应用也降低了设备数量和投资。文中通过对隔壁塔内部结构的讨论和热力学有效能转化的分析,阐释了隔壁塔的节能原理;并以粗苯精制流程中甲苯-二甲苯-重苯的分离为例,在三组元精馏流程的分析之上设计了2套精馏流程方案,对其进行了严格计算和优化,相比于传统的顺序分离双塔流程,隔壁塔可节省能耗41.5%,同时减少了设备的数目和投资。     

反应精馏隔壁塔应用于酯转换过程的研究

提出了一种应用反应精馏隔壁塔把乙酸甲酯废液处理成乙酸正丁酯的新工艺流程,即采用反应精馏隔壁塔替代常规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,考察了进料位置、反应段位置及高度、耦合位置等结构参数对反应精馏隔壁塔的影响,并在保证产品纯度的前提下对反应精馏隔壁塔进行了最优化分析。分析结果显示反应精馏隔壁塔可以节能17.34%,并能有效降低设备投资费用和操作费用。     

基于分壁式精馏塔的甲醇-碳酸二甲酯分离新工艺研究

提出了利用分壁式萃取精馏塔分离甲醇-碳酸二甲酯共沸物的新工艺,分析并建立了分壁式萃取精馏塔的热力学等效模型,利用Aspen Plus对该塔进行模拟和参数优化。主塔理论板数为36块,侧线精馏段理论板数为5块,隔板底端在主塔第27块塔板上,原料进料在第15块板,萃取剂进料在第3块板,回流比为1.2,溶剂比为1.2,在此参数下对分壁式萃取精馏塔进行严格模拟,可得到质量分数99.58%的碳酸二甲酯和99.82%的甲醇,回收萃取剂的质量分数可达到100%。与常规萃取精馏工艺相比,再沸器热负荷降低16.01%,冷凝器热负荷降低13.47%。     

隔壁塔分离乙醇-正丙醇-正丁醇体系

以乙醇-正丙醇-正丁醇为分离体系,研究回流比、气液分配比等操作参数对隔壁塔分离效果的影响。将常规双塔精馏序列转化为隔壁精馏序列并保证各操作参数的最优值,利用Aspen Plus模拟软件对乙醇-正丙醇-正丁醇三组元的常规精馏序列和隔壁塔精馏序列进行模拟分析,探究隔壁精馏工艺最佳操作区域及节能效果,模拟结果表明,在满足分离要求下,气液分配比存在一个相互关联关系,使隔壁塔精馏序列存在一个再沸器热负荷最小的最佳操作区域。与常规精馏序列相比,完成相同的分离任务,隔壁塔精馏序列再沸器节能6 954.368 k W,冷凝器热负荷减少2 934.291 k W。结果表明,隔壁塔精馏序列不但提高了热力学效率、降低了能耗,并且大幅降低设备投资。     

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%。     

分壁式精馏塔分离醇类三元物系的模拟研究

采用分壁式精馏塔分离乙醇-正丙醇-正丁醇三元物系,通过Aspen Plus软件对其进行严格计算.模拟优化之后的塔设备参数和操作条件为：主塔理论板数为35块,进料段理论板数为16块,回流比为9.15,在进料段的第9块板处进料,侧线出料位置为第18块板,隔板的上下端连接位置分别为主塔第10块板和第27块板.与常规的两塔精馏相比,再沸器热负荷减少33.79%.     

分壁式精馏塔精制丁二烯流程模拟

丁二烯是一种重要的石油化工烯烃原料,由于其生产过程能耗高,因此节能降耗成为丁二烯生产工艺的研究热点。利用Aspen Plus模拟软件对丁二烯精制工艺的两套流程进行了模拟研究,考察了分壁式精馏塔(DWC)中内部互连物流连接位置、预分离塔气液相流量和回流比对分离效果和热负荷的影响,对比了相同分离条件下DWC分离流程和传统顺序分离流程的能耗,并根据两套分离流程中塔内液相丁二烯浓度分布情况,分析DWC的节能原因。结果表明,当主塔理论板数105,预分离塔理论板数56,进入预分离塔气相流量1020kmol/h,液相流量890kmol/h,回流比7800时,DWC分离效果最好,丁二烯质量分数可达99.7%,这为DWC精制丁二烯工艺的工业化提供了理论依据。由于DWC有效减少了精馏过程中的返混效应,提高了能量利用率,使其冷凝器可节能29.36%,再沸器可节能29.19%,存在明显的节能优势。     

三元混合物分壁塔精馏分离的研究

提出了甲醇-乙醇-正丙醇三元混合物分壁塔精馏分离的新工艺。通过模拟和灵敏度分析,考察了分壁塔的进料位置、隔板位置、液体分配比、回流比等工艺参数对分离效果的影响,确定了分壁塔的最佳操作条件,并对分壁塔的能耗进行了分析。结果表明,单个分壁塔能达到常规三元混合物分离的要求,并且比常规精馏流程的分离过程节能约30%。     

Energy conserving effects of dividing wall column☆

The energy-conserving performance of dividing wal column (DWC) is discussed in this paper. The heat transfer through the dividing wall is considered and the results are compared with that of common heat insulation dividing wall column (HIDWC). Based on the thermodynamic analysis of heat transfer dividing wall column (HTDWC) and HIDWC, both computer simulation and experiments are employed to analyze the energy-conserving situation. Mixtures of n-hexane, n-heptane and n-octane are chosen as the example for separation. The results show that the energy consumption of HTDWC is 50.3%less than that of conventional distillation column, while it is 46.4% less than that of HIDWC. It indicates that DWC is efficient on separating three-component mixtures and HTDWC can save more energy than HIDWC. Thus it is necessary to consider the heat transfer while applying DWC to industry.     

Design and optimization of a dividing wall column for debottlenecking of the acetic acid purification process

The dividing wall column (DWC) has gained increasing application in a variety of chemical processes because of its potentiality in energy and capital cost savings in multicomponent separations. The main objective in this work is investigation of its use for removing the bottleneck phenomenon within the column when increasing the throughput of an existing distillation process, particularly, the acetic acid (AA) purification process. Optimal column sequence design, involving both conventional and DWC, is considered. The internal recycle flow distribution around the dividing wall was investigated as a primary optimizing variable. Several column arrangements were analyzed to show that the DWC requires less investment and energy costs than conventional distillation, the Petlyuk column, or the prefractionator arrangement.     

Optimal retrofit of a side stream column to a dividing wall column for energy efficiency maximization

A side distillation column is widely used to separate multicomponent mixtures into three products. However, this kind of column consumes considerable amounts of energy due to thermodynamic restrictions and the nature of the distillation process. Retrofit of the side distillation column to a dividing wall column (DWC) can result in significant energy savings. This study evaluated a systematic method for optimal retrofit of a side stream column to a DWC. The minimum energy requirement for the separation of a multicomponent mixture was used for a feasibility study. Subsequently, design and optimization was performed using shortcut, rigorous and response surface methodology. One case study was illustrated to demonstrate the proposed methodology. The results showed that the optimal retrofit of a side distillation column to the DWC could not only save a significant amount of energy, but also increase the capacity. This study highlights the potential for retrofitting a side stream column to a DWC from a techno economic point of view.     

Revamping Dimethyl Ether Separation to a Single‐Step Process

Process intensification techniques were recently proposed to improve the eco‐efficiency of the conventional dimethyl ether (DME) purification and methanol recovery distillation sequence, but they all require new specific equipment and hence rather high investment costs leading to several years of payback time. However, the alternative of reusing the existing equipment to revamp the two distillation columns of the downstream processing section into a single‐step separation was so far overlooked in the open literature. To solve the problem of costly DME separation, a novel single‐step DME separation taking place in a dividing‐wall column (DWC) is proposed that effectively integrates in one shell the tasks of DME purification and methanol recovery. The new process is optimized in terms of minimal energy requirements, taking into account the restrictions caused by reusing one distillation column like, such as limited diameter or reboiler/condenser heat duty. The results demonstrate that the DWC alternative is feasible and has better performances as compared to the classic sequence, i.e., 28 % lower operating costs and 20 % less capital investment.     

Response surface methodology in optimization of a divided wall column

dividing wall column (DWC) is a thermally coupled distillation system with a high energy efficiency that requires lower space and investment compared to the conventional column system. The design of a DWC involves a number of structural and process parameters that need to be optimized simultaneously to improve energetic and economic potential and reduce space requirement. We used response surface methodology (RSM) to optimize DWC nonlinearly and to figure out the effect of parameters and their interactions on energy consumption, product quality, and dimensions of a DWC. Results demonstrate that process variables have significant effects on the energy efficiency of a DWC as compared to the effect of structural variables. The optimum DWC parameters can be found by RSM with minimal simulation runs and the prediction results of RSM agree well with the rigorous simulation results.     

Study of the structural characteristics of a divided wall column using the sloppy distillation arrangement

An efficient design method is proposed for determining the optimal design structure of a dividing wall column (DWC). The internal section of the DWC is divided into four separate sections and matched to the sloppy arrangement with three conventional simple columns. The light and heavy key component mole-fractions are used as the design variables in each column. The structure that gives superior energy efficiency in the shortcut sloppy case also brings superior energy efficiency in the DWC, while the optimal internal flow distribution of the DWC is different from that obtained from the sloppy configuration. Based upon an extensive simulation study, a two-step approach is proposed for the DWC design: the optimal DWC structure is first determined by applying the shortcut method to the sloppy configuration; the optimal internal flow distribution is then found from the corresponding DWC configuration. The simulation study shows that the DWC designed by the proposed method gives a near-optimal structure.     

气相进料对隔板精馏塔优化设计的影响

隔板精馏塔（DWC）在节能和节省设备投资方面具有十分突出的优势,隔板精馏塔中隔板位置是重要的设计变量,影响分离效果及能耗,当进料中含有气相时这种影响更加显著。选用苯、甲苯和对二甲苯三元物系,研究了进料的气相分率对隔板位置的影响并确定最优隔板位置。采用严格模拟方法,以年度总费用（TAC）为评价指标,比较不同进料气相分率下隔板塔的经济性,其中气相进料较液相进料TAC最高可节省23.33%。并通过灵敏度分析展示了在进料中含有气相时确定最优隔板位置的重要性。