隔板塔精馏分离丙酮-乙酸乙酯-水-杂质体系的研究

提出一种隔板塔精馏处理丙酮-乙酸乙酯-水-色素杂质混合物的新工艺。采用aspen plus软件对隔板塔精馏工艺进行模拟,考察回流比和液相分配比对隔板塔分离效果的影响,探讨液相分配比对隔板两侧液相浓度分布的影响规律。结果表明,当回流比为4,气相分配比为0.5时,液相分配比在0.05~0.1范围内,隔板塔的分离效果较好;液相分配比减小,预分馏段液相中乙酯浓度增大,侧线采出段上部的乙酯浓度减小,侧线采出段下部的乙酯浓度增大,预分馏段内乙酯的分割比增大;与原四塔精馏工艺相比,完成相同的分离任务,隔板塔精馏工艺再沸器可节能28.09%,冷凝器可节能27.01%,且节省了设备投资。     

隔板精馏塔分离氯化亚砜的模拟及工艺优化

利用AspenPlus软件对常规的两塔间接序列精馏工艺分离氯化亚砜进行了模拟计算,并提出了一种新型分离工艺—隔板精馏塔工艺。通过对隔板精馏塔的模拟计算,研究了预分离段进料位置、侧线采出位置、回流进料比和分配比对产品纯度和再沸器能耗的影响,结果说明最佳的工艺条件为:预分离段第6块板进料,主塔第55块板采出,回流进料比为4.45,液相分配比为1.60,汽相分配比为1.98。将隔板塔在最佳操作条件下的能耗与常规两塔工艺操作能耗和设备投资进行比较,隔板精馏塔节约冷凝器负荷和再沸器负荷分别为34.62%和34.64%;然后运用专业的设备投资计算软件CAPCOST计算2种工艺设备投资,结果表明,隔板精馏塔新工艺可以降低17.27%的设备投资。综上可知隔板精馏分离氯化亚砜是一种节能、高效的新型分离工艺。     

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。     

用于分离三氯氢硅合成过程中主副产品的隔壁塔模拟

以三氯氢硅合成过程中得到的主副产品混合物二氯二氢硅-三氯氢硅-四氯化硅为分离物系,提出采用隔壁塔代替常规精馏序列分离的新工艺.利用Aspen Plus软件对隔壁塔进行模拟,考察回流比、隔板位置、进料位置、侧线采出位置、液相分配比以及气相分配比对塔顶、侧线以及塔釜产品摩尔分数的影响,得到隔壁塔的最佳工艺参数,并通过模拟比较隔壁塔与常规精馏序列分离此混合物的能耗情况.模拟结果表明:当回流比为6、隔板位置为主塔的第8块板和第24块板、进料位置为预分馏塔的第10块板、侧线采出位置为主塔的第15块板、液相分配比为0.21、气相分配比为0.5时,隔壁塔的分离效果最佳,主产品三氯氢硅的摩尔分数为99.999%;相比于常规精馏序列,隔壁塔再沸器节能29.09%以上,冷凝器节能29.48%以上.     

完全能量耦合精馏塔的设计、模拟与优化

本文针对完全能量耦合精馏塔,基于Fenske-Underwood-Gilliland方程建立了完整的简捷设计方法,得到了各塔的实际理论板数、适宜的进料和侧线液相采出位置以及各塔回流比等参数。并在此基础上通过严格模拟,对完全热耦合精馏塔的中间组分分配比β、气相分割比R_v和液相分割比R_l等参数进行了优化,得出了它们对再沸器热负荷的影响规律。     

Aspen Plus在模拟分离乙腈-水过程中的应用

采用加压-常压双塔精馏分离工艺,对乙腈-水的共沸物进行分离。借助Aspen Plus软件,用Wilson活度系数方程为物性计算方法,以满足乙腈产品纯度分别达到99.5%。以再沸器总热负荷为指标,对理论板数、回流比以及进料位置进行优化,所得最佳工艺参数为:加压塔理论板数为12,回流比为0.7,进料位置为6;常压塔理论板数为11,回流比为0.3,进料位置为7。     

间歇共沸精馏法分离乙二醇单甲醚和水的工艺

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     

萃取精馏分离四氢呋喃-水共沸物的模拟研究

利用化工流程模拟软件Aspen Plus,以DMSO为萃取剂,模拟研究四氢呋喃-水共沸物的分隔壁萃取精馏和单塔侧线采出萃取精馏过程。分隔壁萃取精馏优化后工艺参数为:主塔22块理论板,萃取剂3块理论板处进料,原料17块理论板处进料,回流比0.5,溶剂比0.45;副塔10块理论板,回流比2.4。可得到摩尔分数为99.90%的四氢呋喃和99.19%的水,回收萃取剂的摩尔分数为99.72%。和常规双塔萃取精馏相比,冷凝器热负荷降低18.63%,再沸器热负荷降低15.58%,实现了有效节能。而单塔侧线采出萃取精馏不能实现四氢呋喃和水的有效分离。     

变压精馏分离甲醇与乙腈过程模拟与分析

针对甲醇-乙腈共沸体系的分离,建立了一种加压-常压的变压精馏分离工艺.采用Aspen Plus软件模拟计算,优化加压塔和常压塔的理论板数、回流比、进料位置及能耗.结果表明,较优工艺参数为加压塔操作压力500.0 k Pa,回流比2.4,35块理论板、第23块理论板进料;常压塔操作压力101.3 k Pa,回流比5.6,40块理论板、第13块理论板进料.该条件下高压塔塔釜可得到合格乙腈产品,低压塔塔釜可得到合格甲醇产品.优化后再沸器节约能耗约35.3%,冷凝器节约能耗约45.8%.     

丙酮-氯仿共沸体系萃取精馏过程模拟与优化

应用化工过程模拟软件Aspen Plus对丙酮-氯仿最低共沸物系的连续萃取精馏过程进行了模拟与优化。通过Aspen物性分析,筛选出合适的萃取剂为二甲基亚砜。确定了双塔连续萃取精馏的工艺流程,并利用灵敏度分析工具考察了萃取精馏塔的理论塔数、回流比、原料进料位置、萃取剂进料位置、溶剂比(萃取剂对原料的物质的量比)对分离效果的影响。确定的最佳工艺方案为:全塔理论板数为45,原料和萃取剂分别在第11块和第3块理论板进料,回流比为2.5,溶剂比为1.9。在此工艺条件下:萃取精馏塔塔顶丙酮的分离效果达99.95%,萃取剂回收塔塔顶氯仿的纯度达到98.34%;萃取剂二甲基亚砜的循环补充量为5.557mol/h。模拟与优化结果为丙酮-氯仿共沸物连续萃取精馏分离过程的设计和操作提供了参考。     

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%。     

Effects of Thermal Feed Quality on the Performance of a Divided Wall Distillation Column

The present work deals with the effect of thermal feed quality on the performance of a divided wall distillation column (DWC). The thermal condition of the feed alters the pressure profile across the two sides of the dividing wall, thereby affecting not only the mass transfer characteristics but also the hydrodynamics of a DWC. It was observed that the natural (feasible) vapor split ratio does not depend on the liquid split ratio and the reflux flow rate when the feed is saturated liquid or sub-cooled liquid (q ≥ 1). However, for q < 1, that is, for two phase (vapor-liquid), saturated vapor, or superheated vapor feed, the liquid split ratio and the reflux flow rate have profound effect on the feasible vapor split ratio, and the pressure profiles are altered significantly. For the stable operation of a DWC, the feed should be either saturated liquid or sub-cooled liquid or the feed quality may be manipulated to adjust the vapor split ratio.     

Separation of ethyl acetate–isooctane mixture by heteroazeotropic batch distillation

This paper studies the separation of an ethyl acetate–isooctane mixture by heterogeneous azeotropic distillation in a batch rectifying column. An initial list of 60 candidates was studied but only methanol and acetonitrile were obtained as potential heterogeneous entrainers. These entrainers form a low boiling heterogeneous azeotrope with isooctane. Experimental verification of the miscibility gap with isooctane was performed at 25 °C for each entrainer giving a smaller region for methanol than for acetonitrile. Feasibility of the heterogeneous azeotropic batch distillation was carried out experimentally in a laboratory batch distillation column having 44 theoretical equilibrium stages and using a high reflux ratio. Several distillate fractions were taken as a function of the temperature at the top of the column. For both methanol and acetonitrile, the main fraction was defined by the condensed vapor providing a liquid–liquid split of the isooctane/entrainer heteroazeotrope into the decanter. Ethyl acetate impurity was detected in both decanted phases, but in much lower amount when using acetonitrile as entrainer. The process with acetonitrile also resulted in a shorter operating time and higher purity and recovery yield of isooctane as the main distillate product. Pure ethyl acetate remained into the boiler at the end of each process.     

内部热耦合精馏塔的操作性能与模拟

对同轴式内部热耦合精馏塔的操作性能和节能效果进行了研究,考察了全回流操作条件下,压缩比对回流量、冷凝器负荷和再沸器负荷的影响。结果表明,随着压缩比的增大,回流量、冷凝器负荷和再沸器负荷均降低。通过实验数据计算得到了该塔的理论板数和两塔间的传热量,精馏段为9块理论板,提馏段为4块理论板,当压缩比为2.2:1时,两塔间传热量为9.98kW。连续操作条件下,对内部热耦合精馏塔的节能效果进行了分析,通过与常规精馏塔的比较,内部热耦合精馏塔可节约52.3%的冷量,输入的再沸器和压缩机总负荷可节约20.34%。另外,基于实验数据,对该内部热耦合精馏塔进行了动态模拟,经连续操作下的实验验证,该内部热耦合精馏塔可在2h后达到稳定操作。     

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%.     

分壁精馏塔分离苯/甲苯/二甲苯的模拟工艺研究

分壁精馏塔（简称分壁塔）在节能和节约投资方面都有很大的优势和潜力,因此近几年来人们对它的深入研究也越来越多。以等比例的苯、甲苯和二甲苯为原料,通过模拟工艺流程,研究分析了分壁塔的进料位置、隔板位置、回流比、侧线采出位置以及液汽相分流比与能耗、组分纯度的关系。研究结论显示,分壁塔的最适宜液相分流比和汽相分流比分别为0.65和0.45,与常规精馏塔相比,分壁塔分离所得的苯、甲苯和二甲苯的纯度高,冷凝负荷和热负荷分别比常规精馏塔降低31.066 9%和34.167 5%。     

萃取精馏分离异丙醇-水共沸体系的模拟与优化

对异丙醇-水共沸体系的萃取精馏过程进行模拟与优化。以乙二醇为萃取剂,基于UNIFAC模型,使用Aspen Plus化工模拟软件中的RadFrac模块进行萃取精馏模拟,并利用灵敏度分析模块对各工艺参数进行灵敏度分析与优化。结果表明,以乙二醇做萃取剂分离异丙醇-水共沸体系是可行的。对于处理流量5000kg·h-1的异丙醇-水共沸溶液,精馏塔具有22块塔板时,原料进料位置在第16块塔板,萃取液进料位置在第3块塔板,摩尔回流比为1.4,萃取剂与原料的进料比为2∶1,塔顶异丙醇质量分数可达0.9981,萃取精馏塔的分离效果和热负荷达到最优。模拟和优化的结果对工业化设计和生产具备指导意义。     

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.