多进料填补隔离壁精馏塔的黑洞问题

由于隔离壁精馏塔(DWDC)的预分离塔和主精馏塔之间存在着强烈的物质耦合与能量耦合,其在四点浓度(3个主要产品的采出浓度和中间产物的杂质浓度比)的控制条件下,存在设计和操作的黑洞问题。利用多进料策略的综合设计方法有效地对黑洞进行了填补,通过对实际物系乙醇、丙醇、丁醇分离系统的稳态分析和动态研究,验证了该方法的可行性及有效性,并证明了该方法的节能优势。     

外部环流反应隔离壁精馏塔的综合与设计

提出了一种外部环流反应隔离壁精馏塔,隔板的设置使得未转化的反应物能够被限制在隔板的进料一侧和塔的两端,尽可能地减少通过侧线采出位置的未转化反应物。基于乳酸和甲醇的酯化反应,以年总投资(TAC)为目标函数,分别设计了最优的外部环流反应精馏塔和外部环流反应隔离壁精馏塔。对比结果显示,后者相对前者TAC减小了27.92%。     

分壁精馏塔分离对二甲苯吸附抽出液的工艺分析

分壁精馏塔具有投资少、能耗低的优点。以芳烃联合装置中的吸附抽出液分离为例,采用ASPEN软件进行模拟计算,考察了分壁精馏塔的各段理论板数、气液相分配比、回流比、进出料位置对分离结果的影响。结果表明,在分壁精馏塔的理论板数为80～90、分壁段的理论板数为40～50、公共精馏段和公共提馏段的理论板数为15～20、进料位置为进料段的第15～25块理论板、侧线采出位置为侧线产品段的第25～30块理论板、回流比为100～110、气相分配比为0.85～1.75、液相分配比为0.5～0.9的条件下,分离得到的甲苯、对二甲苯、对二乙苯的纯度均不低于99.9%;在相同的产品质量和收率下,采用分壁精馏塔较现有的两塔分离工艺总能耗降低22.02%,具有明显的节能优势。     

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%。     

异戊橡胶生产中溶剂回收和单体精制工艺节能优化研究

利用Aspen plus(version:11.1)软件对稀土异戊橡胶溶剂回收和单体精制流程进行模拟,在确保从侧线采出的精制己烷和精制异戊二烯产品满足聚合要求的前提下,将传统的四塔流程优化为双塔侧线采出流程。通过分析比较2个侧线采出精馏塔之间的冷、热量平衡关系,将2个精馏塔进行了热集成,并对热集成后异戊二烯精制塔塔釜再沸器的控制方案进行初步探讨。通过软件模拟,在相同操作条件下,双塔侧线热集成精馏流程能够节省约46.98%的热量和45.90%的冷量消耗。     

低温精馏过程模拟及其分离特性分析(Ⅱ)带有侧线返回进料的低温精馏塔模拟

应用严格的热力学模型研究了带有侧线返回进料的氢同位素低温精馏塔的分离特性.根据氢同位素低温精馏体系的特点，以平衡级模型为基础建立了氢同位素低温精馏稳态模拟模型，确定了模型方程适宜的求解方法.塔的一股侧线出料流股经过一个平衡反应器完成平衡反应后，作为内部进料流股，与原外部进料混合后重新进入精馏塔内进行分离操作.通过对带有侧线返回进料的塔的计算模拟阐明了这一侧线流股对塔分离特性的影响.在平衡反应器内，HD部分分解为H₂和D₂，塔顶产品中H₂的浓度增加了8.635%，塔底D₂的浓度增加了11.327%.     

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。     

一种新型双隔壁反应精馏塔及其性能

采用常规反应精馏塔系分离具有最不利相对挥发度排序的四元可逆反应物系会要求反应精馏塔侧线出料具有过低的反应物浓度,这既不利于反应物的转化又增加了系统的能耗。为解决这一问题,可对常规反应精馏塔系做如下改进:从常规精馏塔引出一条气相物流加热反应精馏塔;在两塔连接物流中引入物质传递操作;将两塔集成于一个塔壳中,由此给出了一种新型的双隔壁反应精馏塔。该双隔壁反应精馏塔能够容忍左隔离壁顶端处轻反应物浓度较高。以四元理想反应物系的分离为例,对常规反应精馏塔系与该双隔壁结构进行比较与分析。结果表明,后者明显优于前者,具有较低的设备投资与操作能耗。基于化学平衡常数和产物摩尔分数进行摄动分析,所得结果也表明该双隔壁反应精馏塔的稳态性能具有较强的鲁棒性。     

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。     

甲醇精馏系统常见问题的处理

介绍甲醇精馏工艺流程,分析了精甲醇产品酸度和碱度高的原因。在精馏操作中,通过预精馏塔p H和预塔不凝气温度的控制、合成反应气体成分和空速的控制、常压精馏塔侧线采出量的控制、加压塔与常压塔回流比的控制等方法,可保证产品酸碱度在合格指标之内。     

Elevating the flexibility and operability of dividing-wall distillation columns via feed thermal condition adjustment

Because of the complicated interplay between the prefractionator and main distillation column involved,the black-hole problem might occur and prohibit the assignment of four specifications to dividing-wall distillation columns (DWDCs) (e.g.,the three main product compositions plus an impurity ratio in the intermediate product),which lowers terribly process flexibility and operability.In this paper,a feed thermal condition adjustment strategy,achieved by the installation of a pre-heater in feed pipeline,is employed to eliminate the black-hole problem and serve to enhance process flexibility and operability.Through the strong influence to the overall mass and energy balance of the DWDC,the feed thermal condition adjustment can alter the interlinking flows between the thermally coupled prefractionator and main distillation column and work effectively to coordinate their relationship.A DWDC separating a benzene,toluene,and o-xylene mixture is chosen to ascertain the feasibility of the philosophy proposed.The static and dynamic studies demonstrate that the feed thermal condition adjustment is an effective way to refine process design and can completely eliminate the black-hole problem and elevate consequently process flexibility and operability.     

基于粒子群算法的隔离壁精馏塔的综合与设计

隔离壁精馏塔（dividing-wall distillation column,DWDC）是提高两个或者多个传统精馏塔热力学效率的有效手段。由于隔离壁精馏塔内部结构复杂、相互作用强,传统的序贯优化方法计算时间长,很难达到全局最优解。标准粒子群算法应用广泛、易于实现,但易于早熟、易于陷入局部极值点。因此,本工作采用改进的元胞粒子群算法对Kaibel隔离壁精馏塔进行综合与设计研究。元胞粒子群算法通过改进粒子的学习策略,采用元胞邻域的方法可有效地将粒子分散在多个子空间。对比标准粒子群优化和元胞粒子群优化两种方法的50次优化效果,结果表明,两种粒子群算法能够对内部结构复杂、相互作用强的四组分Kaibel隔离壁精馏塔这一复杂分离系统进行优化,优化效果显著。     

Vapor recompressed dividing-wall distillation columns: Structure and performance

Due to the topological structure of double columns and multiple separating sections in dividing-wall distillation columns (DWDCs), the development of vapor recompressed dividing-wall distillation columns (DWDC-VRHPs) represents a challenging issue with great complexities and tediousness. For the separations of light-component dominated and wide boiling-point ternary mixtures, because the purification of the light-component from the intermediate-and heavy-components incurs the primary energy dissipation, the application of vapor recompressed heat pumps (VRHP) should be aimed to reduce the irreversibility and this leads to the generation of the optimum topological structures of the DWDC-VRHPs, i.e., a DWDC plus a two-stage VRHP. The first-stage VRHP is to preheat feed, not only taking the advantages of the small temperature elevation available but also favoring the mass transfer between the vapor and liquid phases through feed splitting. The second-stage VRHP is to reduce further separation irreversibility. The philosophy can be applied to any DWDCs no matter where the dividing wall locates. Two case studies on the separations of ternary mixtures of benzene, toluene, and o-xylene and n-pentane, n-hexane, and n-heptane demonstrate the economic optimality of the proposed DWDC-VRHPs and reveal the inherent interplay between internal and external process integration.     

Design and control of butyl acrylate reactive distillation column system

In this study, the design and control of a reactive distillation column system for the production of butyl acrylate has been investigated. The proposed design is quite simple including only one reactive distillation column and an overhead decanter. The optimal design is selected based on the minimization of total annual cost (TAC) for the overall system. At this optimized flowsheet condition, output multiplicity was found with reboiler duty or feed ratio as the bifurcation parameter. The highest purity stable steady state was selected as the base case condition for the control study. The overall control of this system can be achieved with no on-line composition measurements. Simple single-point tray temperature control loop is designed to infer final product purity. From results of dynamic simulation, the proposed control strategy performs very well in rejecting various disturbances while maintaining butyl acrylate product at high purity. One of the important finding in this paper is that it is better to operate this reactive distillation column not at the exact feed stoichiometric balance point for better operability reason. The control performances of the proposed operating point and the operating condition right at the exact stoichiometric balance point will be compared.     

Dividing wall columns: Fundamentals and recent advances

Different distillation sequences for the separation of near-ideal multicomponent mixtures have been proposed in the past. These sequences included both conventional and thermally coupled distillations. Investigations of these sequences based on thermodynamics and steady-state simulations aimed for identifying the economic and energetic favourable configuration. Dividing wall columns have shown to be superior to conventional distillation sequences in certain cases. For this reason dividing wall columns gained increasing application in the last years. More than 90 applications in production scale are known. The advantages are obvious. Depending on the case considered the energy and investment costs are reduced up to 30% compared to conventional technologies. The footprint is significantly smaller. Also advantageous is the higher flexibility of these systems in comparison to conventional column sequences. For temperature-sensitive products the thermal stress is reduced since the product is reboiled only once. Especially for high price products the product quality can be raised by simultaneously increasing the separation yield.     

考虑不同产品选择性目标的乙醇胺反应精馏塔模拟与优化

提出以环氧乙烷和液氨为原料,水为催化剂,反应精馏塔合成乙醇胺的工艺。分别以一乙醇胺（MEA）和二乙醇胺（DEA）的选择性最大为目标,探讨了在同一反应精馏塔中实现不同产物选择性目标的可行性和可达到的最大选择性。研究在Aspen Plus模拟软件上进行,通过考察操作压力、水进料量、进料氨烷比、再沸比、环氧乙烷进料位置等参数对反应精馏的影响规律,取得实现不同产物选择性目标的参数优化调节方法。研究表明,大的氨烷比、水进料量和再沸比有利于提高MEA选择性,小的氨烷比、水进料量和再沸比则有利于提高DEA选择性,在优化条件下,MEA选择性可达70.30%,DEA选择性可达41.89%。与文献方法比较,采用反应精馏合成乙醇胺具有明显的优越性和操作柔性。     

Structural design of fully thermally coupled distillation column using approximate group methods

The thermally coupled distillation column systems can save energy and capital cost compared with traditional distillation columns. Since the thermally coupled column system was introduced, the design concerns have been peeped out due to more degrees of freedom. This paper introduces a new design method that can be used to determine the structure of thermally coupled distillation column systems, namely the number of stages in all sections of the column system. The design method employs the approximate group methods. To explore the design performance of the proposed design method, three feed systems are analyzed to investigate its usefulness. The design procedure gives the optimum structure for a given ternary separation; with given product specifications various design methods can yield approximately the same results. Like structure designs, the optimal internal flow distributions are examined. The results indicate that the method works well for a variety of process conditions.     

乙酰丙酸乙酯的反应精馏模型及隔壁塔节能优化设计

乙酰丙酸乙酯是一种潜在的生物质基平台化合物,在工业上具有很高的应用价值。乙酰丙酸乙酯传统的生产方法主要为间歇反应法,效率较低,产物分离困难且工艺流程较长。因此,本文提出了反应精馏工艺生产乙酰丙酸乙酯,在以中试实验结果为依据的基础上,使用Aspen Plus模拟软件建立了工艺流程,并考察了回流比、进料位置、进料摩尔比以及理论塔板数等关键参数,得到了常规单塔反应精馏工艺生产乙酰丙酸乙酯的最优配置。而后,为了得到纯度大于99.9%的乙酰丙酸乙酯,本文进一步提出了反应精馏双塔精制流程以及反应精馏隔壁塔流程,并通过对两种流程所得到的产品纯度以及能耗的对比,验证了反应精馏隔壁塔工艺生产乙酰丙酸乙酯的有效性以及在节能方面较大的优势。     

浅析预精馏塔在甲醇精馏过程中的重要意义

介绍了预精馏塔的工艺流程,通过控制不凝气温度、萃取水、碱液等几个调节方法,分析了预精馏塔在甲醇精馏中的主要作用。     

分壁精馏塔分离芳烃的稳态及动态研究

采用分壁精馏塔（DWC）严格稳态模型,对比苯、甲苯、二甲苯以及均三甲苯四组分混合物的常规分离和分壁精馏塔分离方法,稳态分析结果表明：直接序列分壁精馏塔流程较常规三塔分离序列可减小再沸器负荷18.9%,年度总成本TAC可降低13.0%,DWC有效避免了常规塔器分离过程中中间组分的返混现象。在Aspen Dynamic环境下对最优序列进行组分控制,结果表明组分控制可很好地应对进料流量和组分组成波动。