反应/分离集成系统塔板组成线设计法研究

反应/分离系统的集成是对现有工业过程进行强化的主要途径之一。文中在精馏塔板组成线的基础上,推导出了反应精馏塔板组成线基本方程及设计可行性判据,提出了给定进料和一个目标产品组成的塔板组成线反应精馏设计的新策略,并对非理想性较强的MTBE反应体系进行了实例设计计算。结果表明,提出的设计策略能同时获得多组可行设计方案,可有效地对单一和集成型反应精馏塔进行设计,结果与Aspen P lus的模拟结果吻合较好。     

非理想溶液间歇精馏的计算机辅助设计

为了提高二元非理想溶液间歇精馏的设计效率,提出了恒馏出液组成和恒回流比两种间歇精馏操作方式的计算机辅助设计法。采用由智能拟合法得到的汽液相平衡方程逐板计算求理论塔板数,高斯-勒让德数值积分法求有关积分,可视化的Visual Basic 6.0语言编制设计软件。将设计参数输入软件,可快速准确地求出二元非理想溶液间歇精馏的众多设计和操作参数,还可求出回流比与釜液温度的关系,实现由釜液温度前馈控制间歇精馏过程。计算机辅助设计法极大地提高了二元非理想溶液间歇精馏的设计效率。     

催化重整精馏装置的模拟仿真与操作优化

为了优化精馏装置的操作参数,提高工业生产过程中芳烃的产品收率,提出了50万t/a催化重整装置的设计方案。首先对催化重整芳烃精馏过程进行了认知与分析,指出关键参数的选取与判断是设计过程中的难点。在此基础上运用流程模拟软件Aspen Plus建立模型并对芳烃精馏过程进行模拟,包括对苯塔、甲苯塔、二甲苯塔的模拟与分析,得出每个精馏塔的主要操作条件与参数。然后结合芳烃精馏模拟结果,分析塔板数、回流比、进料位置、操作压力对精馏的影响,确定最优操作参数。模拟结果表明,参数优化有效且可行,对工业生产过程中相关参数的设定有重要的指导意义。     

乙醇平流双效及三效精馏节能工艺模拟研究

本文以典型的平流双效精馏和平流三效精馏为例,以高度非理想体系乙醇-水溶液为物系,建立起非理想体系平流多效精馏数学模型并求解,得到各效精馏塔的工艺参数,研究结果表明,平流三效精馏比平流双效精馏节约生蒸汽用量21.4%,但塔板数比双效精馏增加了36.4%;在设计多效精馏塔时还应考虑压力的影响,随着效数的增加,首效精馏塔的压力也是急剧增大,对分离不利,同时要考虑高压设备的投资及维护费用,不建议采用四效以上的多效精馏工艺流程。研究结果为平流多效精馏这一重要的分离过程提供基础数据,对精馏过程的节能降耗具有重要的指导意义。     

变压精馏分离甲醇-丙酮的工艺模拟及优化

采用Aspen Plus软件,以塔釜能耗为目标,以甲醇、丙酮纯度为约束函数,对双效变压精馏分离甲醇-丙酮工艺过程进行模拟。分析了操作压力、理论板数、回流比、进料位置和进料温度等参数对精馏过程的影响。确定了最优工艺参数：减压塔操作压力40 kPa,理论板数37,回流比2.4,进料塔板数26,进料温度25 ℃;常压塔理论板数30,回流比4.2,进料塔板数23。减压塔所得甲醇质量分数为99.0%,常压塔所得丙酮质量分数为99.7%。对比变压精馏和萃取精馏过程,变压精馏更容易得到高纯度丙酮产品,节能约13.4%。模拟结果对工业设计和设备改造具有一定指导意义。     

反应精馏法合成醋酸丁酯的模拟研究

文章采用Aspen Plus对反应精馏法生产醋酸丁酯过程进行稳态模拟。对塔板数、进料位置及进料比进行了优化,得到了精馏塔理论板上的温度、汽(液)相流量组成分布和再沸器热负荷。结果表明进料位置和进料比对年总成本TAC影响很大。该计算对反应精馏法合成醋酸丁酯工艺的设计和操作具有实际意义。     

CFC-113反应精馏合成CFC-113a的过程模拟与优化

将反应精馏技术应用于CFC-113转产CFC-113a的工艺,利用Aspen Plus软件对反应精馏制备CFC-113a的稳态工艺过程进行了研究。分别从操作压力、精馏段塔板数、反应段塔板数、提馏段塔板数和回流比等方面对该反应精馏系统进行了优化,该优化结果的获取旨在推动新工艺的工业化。     

间歇精馏操作型快速计算方法

本文讨论双组分混合物在间歇精馏中的操作型计算方法,该法是在适当的近似假设下获得无穷多块塔板时的间歇精馏操作型计算式,过程简明,不需图解。同时发现,有限塔板数与无穷多块塔板数的计算结果十分相近。     

反应精馏制备乙酸乙酯的工艺分析

为揭示反应精馏法制备乙酸乙酯的特性及得到较高纯度的产品,并为反应精馏工艺过程的深入研究及工业化提供理论依据,应用Aspen Plus软件模拟分析反应精馏过程。结果表明：给定回流比的情况下,理论塔板数、精馏段塔板数及进料位置、进料比、催化剂用量等参数均对产品纯度及分离效果产生影响。     

多组分精馏故障诊断和生产优化

应用多组分精馏原理,从设计角度对实际运行的精馏装置的不稳定操作进行了故障诊断,考察了回流比、回收率、进料温度和热状态对塔的加料位置和实际塔板数的影响;同时应用正交设计对各工艺条件进行了优化.实际操作数据证明故障判断准确,处理有效,获得了较好的经济效益.     

用夹紧区原理确定多元恒回流比分批精馏最小回流比

夹紧区是精馏塔内出现的浓度几乎不变的区域,对于三元物系来说,根据夹紧区在塔内出现的位置可分为：上、中和下加紧区.在无穷板数和任一瞬时釜浓下选择不同的回流比可使分批精馏处于不同夹紧区下操作.文中讨论了三元恒回流比分批精馏过程中夹紧区的演变,在Rayleigh方程的基础上建立了应用夹紧区原理确定多元恒回流比分批精馏最小回流比的方法.该方法并不要求相对挥发度为常数,并且能准确计算顶浓,克服了通常所采用的Underwood公式法的缺陷,为多元分批精馏的简捷设计奠定了基础.     

Minimum reflux calculation for multicomponent distillation in multi-feed,multi-product columns: Mathematical model

Multi-feed, multi-product distillation columns are ubiquitous in multicomponent distillation systems. The minimum reflux ratio of a distillation column is directly related to its energy consumption and capital cost. Thus, it is a key parameter for distillation systems design, operation, and comparison. In this series, we present the first accurate shortcut based algorithmic method to determine the minimum reflux condition for any general multi-feed, multi-product (MFMP) distillation column separating any ideal multicomponent mixture. The classic McCabe-Thiele or Underwood method is a special case of this general approach. Compared with existing techniques, this method does not involve any rigorous tray-by-tray calculation, nor does it require guessing of key components. In this first part of the series, we present the mathematical model for a general MFMP column, derive constraints for feasible separation and minimum reflux condition, discuss their geometric interpretations, and present an illustrative example to demonstrate the effectiveness of our approach.     

An iteratively refined distillation line method

The focus of this article is distillation design feasibility. It is shown that existing methods for determining feasibility can give incorrect results or produce feasible designs that waste energy due to over‐specification and mass balance errors. An iterative refinement procedure based on direct substitution is proposed within the distillation line method of Lucia et al. that automatically adjusts one product composition to determine feasibility. Direct substitution equations are presented in detail and 14 literature examples are used to illustrate the efficacy of iterative refinement. Numerical results show that iterative refinement can find feasible designs that other methods cannot find, often resulting in significant reductions in energy requirements, and that it is all product compositions, not just trace compositions that affect most shortcut methods for distillation design. Iterative refinement can also find minimum energy requirements and identify sets of specifications that give infeasible designs. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

反应精馏过程图解法设计策略研究

从反应精馏过程图解法设计的理论研究出发,探讨了反应空间、转换组成变量以及剩余曲线等应用范围和局限性;通过分析反应精馏操作线方程的变化,提出了图解法设计反应精馏过程的策略;（1）用奇异点判断法结合实验数据可判定应用反应精馏过程的可行性;（2）借助反应空间可判断该过程能否在单塔中得到完全分离;（3）图解法设计的多种设计结果及相应对策。采用实例验证了该策略的可行性。     

分批蒸馏优化策略与微机控制的研究(Ⅰ)——分批蒸馏的优化策略

本文提出了塔顶累积全回流及变压强综合回流两个分批蒸馏的新操作策略及相应的优化操作法,通过数学模拟和θ收敛计算法求出了二元(乙醇—异丙醇)和多元(正庚烷—正辛烷—正壬烷—正癸烷)物系的数值解.计算结果表明,两种新操作法分别较传统的操作法缩短生产周期30%和50%以上.     

A method for the design of flexible distillation sequence

A simple method has been developed to optimally design a distillation sequence with a fixed degree of flexibility in feed composition and flowrate, and accounts for uncertainty in stage efficiency, K-value and beat transfer coefficient calculations. The method minimizes a weighted cost function and ensures both optimal and feasible operation in the range of flexibility/uncertainty by using an approach termed “practical feasibility”. The method was tested on a 4 column distillation sequence separating a 5 component light alkane feed mixture. Results are presented to illustrate the effect of uncertainty on sequence cost and column overdesign.     

基于优化的反应精馏塔简捷设计

基于G ibbs自由能最小原理达到反应和相平衡的假设,提出了一种适用于初步设计的新的设计方法。以甲基叔丁基醚和碳酸二乙酯的反应精馏过程为例,应用Aspen软件模拟,经分析发现,通过改变理论级数和回流比,可得到合理的塔内温度分布,从而使塔底产品组成得到最大程度的提高,为此提出基于优化的设计法:以产品组成最大为目标函数,以回流比、精馏段和提馏段理论板数为决策变量,采用遗传算法进行优化计算。结果表明,2个设计实例均能在保证低能耗的同时得到较高的产品纯度,说明该设计方法可以设计出较好的反应精馏塔。     

Heat‐integrated distillation columns: Vapor recompression or internal heat integration?

Internally, heat‐integrated distillation columns (HIDiC) and vapor recompression (VRC) constitute alternative design options to provide sustainable distillation processes. However, the design is often based on heuristic rules or the experience of the designer, as no systematic methodology driven by economics has been established so far. The increased complexity of heat‐integrated columns can hardly be dealt with using simulation studies but rather calls for a systematic design procedure. A new design methodology is presented here; it builds on a superstructure, mixed‐integer minimization of total annualized cost of operation and rigorous thermodynamic modeling. Optimal VRC and HIDiC designs are identified for the separation of binary, multicomponent, and nonideal mixtures and benchmarked against conventional distillation column designs. A small number of intermediate heat exchangers is optimal for these HIDiC configurations, eventually reducing to a single heat exchanger similar to VRC. Therefore, VRC designs are often more cost efficient due to simpler equipment. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

REDUCING STATIC DEVIATIONS OF PRODUCT QUALITIES IN THE TEMPERATURE CONTROL OF AN IDEAL HEAT-INTEGRATED DISTILLATION COLUMN

Two strategies are proposed in this work for the reduction of static deviations of product qualities in the dual-point temperature control of a simulated ideal heat-integrated distillation column. The key to achieve this purpose is to sense the changes in operating conditions and make appropriate adjustments simultaneously to the set-points of the top and bottom control loops. The first method is based on the inferential signals extracted from the composition of products and the second one from the temperatures of the top and bottom stages. Both strategies are intensively studied through the operation of the simulated ideal heat-integrated distillation column separating a binary equimolar mixture of benzene and toluene, and it is found that they could work effectively to decrease the static deviations in product qualities. The strategies are characterized by great simplicity in principle and a relatively small effort in process modeling, thereby allowing wide applications in the operation of various distillation columns with a dual-point temperature control scheme.