过量进料反应隔离壁蒸馏塔的设计与比较

采用反应物过量技术克服反应蒸馏塔在分离具有较不利动力学特性的反应混合物时的缺陷,提出针对此类反应精馏的最优蒸馏塔结构设计策略。针对具有较不利相对挥发度排序的四元理想可逆放热反应,分别设计常规反应蒸馏塔(RDC)与采用反应物进料过量技术的反应隔离壁蒸馏塔(ER-DWDC),并对其稳态性能进行评价。结果显示,反应物中轻组分进料过量的反应隔离壁蒸馏塔能够最大程度强化蒸馏塔内部物质和能量耦合,具有优越的稳态性能,能够显著降低工业分离过程中的设备投资成本和操作能耗。     

多反应段蒸馏塔的设计与控制

针对多步连续可逆反应,系统地探究了多反应段蒸馏塔设计的有效性与可行性。以两步连续可逆反应合成碳酸二乙酯和三步连续可逆反应制备硅烷为例,从稳态到动态进行了单反应段蒸馏塔和多反应段蒸馏塔的比较与分析。结果显示,多反应段的引入有助于协调多步反应之间以及反应操作与分离操作之间的相互关联,不仅能够提升系统的稳态性能,还能够改善动态特性与可控性。因此,针对多步连续可逆反应物系的分离问题,多反应段设计方法是一种行之有效的过程强化手段。     

外部环流强化乙酸丁酯反应隔离壁蒸馏塔

针对具有较不利相对挥发度排序的四元可逆反应体系,使用常规反应蒸馏塔分离会使未反应的最重和次轻反应物堆集在塔底和反应段的顶部,降低反应的转化率。为解决这一问题,提出了2种不同的外部环流反应隔离壁蒸馏塔结构:中部环流反应隔离壁蒸馏塔和底部-中部环流双反应段隔离壁蒸馏塔。通过设置外部环流,将塔内未反应的反应物引回至反应段进行反应,同时环流实现的前提是在塔内设置隔离壁。以乙酸丁酯和乙醇的转酯反应的分离为例,对2种外部环流反应隔离壁蒸馏塔结构的有效性和可行性进行评估。研究结果表明:外部环流反应隔离壁蒸馏塔与传统反应蒸馏塔相比,稳态性能显著提高,具有更好的分离效果和经济性能。     

乙酸甲酯外部环流隔离壁反应蒸馏塔的设计与比较

选择了3种不同的外部环流设计并采用隔离壁蒸馏塔的拓扑结构。以乙酸和甲醇酯化反应生成乙酸甲酯和水反应体系为例,分别设计了底部-中部环流隔离壁反应蒸馏塔、中部-中部环流隔离壁反应蒸馏塔和双环流隔离壁反应蒸馏塔,并对其稳态性能进行了分析与比较。结果显示,双环流隔离壁反应蒸馏塔能够最大限度地强化内部物质和能量耦合,因而拥有最佳的稳态性能。     

单环流反应隔离壁蒸馏塔的设计与控制

提出了一种单环流反应隔离壁蒸馏塔,基于合成乙酸甲酯的酯化反应,以全年总投资(TAC)为目标函数,设计了最优的单环流反应隔离壁蒸馏塔结构,采用两点温度控制策略研究了单环流反应隔离壁蒸馏塔的动态性能。结果表明:相比于外部环流反应蒸馏塔,单环流反应隔离壁蒸馏塔的设备投资费用降低了0.63%,操作费用降低了11.62%,TAC减少了7.86%。对于进料流量以及进料组分的扰动影响,两点温度控制能够使得产品浓度能够在很短的时间内恢复到误差允许范围内的稳定值,表明该控制策略能够有效应对进料流量以及进料组分的扰动。     

化工专利

一种催化蒸馏生产二甲醚的方法公开(公告)号:CN101475452公开(公告)日:2009.07.08一种催化蒸馏生产二甲醚的方法,包括以下步骤:①将原料引入到一个催化蒸馏塔中,使一部分原料在催化蒸馏塔的反应段反应生成二甲醚和水;②催化蒸馏塔塔顶的     

双反应段蒸馏塔的动态特性与控制

针对理想两步连续可逆反应,通过开环和闭环仿真研究了双反应段蒸馏塔(RDC-DRS)的动态特性和可控性。开环仿真结果显示:对于调节通道,尽管双反应段的安排使得塔顶产品浓度和回流流量之间的过程增益有所降低,但也减弱了塔顶产品浓度和再沸器之间的相互耦合。相比于单反应段蒸馏塔(RDC-SRS),RDC-DRS的可控性仍有所提高。对于扰动通道,双反应段的安排并没有改变系统对进料流量扰动的灵敏度。闭环仿真结果显示:在进料流量扰动和组分扰动的情况下,相比于RDC-SRS,RDC-DRS表现出更好的抗干扰性能。综合上述结果可知,针对理想两步连续可逆反应的分离操作,RDC-DRS比RDC-SRS具有更优越的动态特性和可控性。     

一种通用的反应蒸馏塔综合与设计方法

反应精馏是反应过程和分离过程耦合为一体的单元操作,已成为当今研究的重要领域。然而,到目前为止并没有一套通用简便的方法去指导反应精馏过程的综合与设计,严重限制了它的广泛应用。本文在过程强化原理的基础上提出了一种反应蒸馏塔通用的综合与设计方法,并利用2种反应蒸馏系统来评价所提出的设计策略。结果表明,该综合设计方法可以简便高效地搜索出反应蒸馏塔的最优结构,适用于不同类型的反应蒸馏塔的综合与设计。     

异戊烯装置催化蒸馏塔的工艺优化

从催化蒸馏的工艺操作入手,针对操作过程中出现的催化蒸馏塔内二聚反应的发生及控制、催化蒸馏塔釜TAME含量的控制、催化蒸馏塔内二甲醚副反应的发生及控制等问题,进行探讨、分析并进行优化。     

醚化蒸馏塔设计总结

大连石化公司汽油质量升级100万t/a轻汽油醚化装置醚化蒸馏塔具有塔内装有填料和塔盘、外形尺寸大、变径以及由于物料反应介质腐蚀性较大的特点,正确的设计对于醚化蒸馏塔的长周期安全使用具有重要意义。阐述了醚化蒸馏塔的主体材料选用、结构型式和制造安装技术要求编制等方面的设计要点。     

Quantitative comparison of dynamic controllability between a reactive distillation column and a conventional multi-unit process

A comparison of the steady-state economic optimum designs of two alternative chemical processes was presented in a previous paper [Kaymak, D. B., & Luyben, W. L. (2004). A quantitative comparison of reactive distillation with conventional multi-unit reactor/column/recycle systems for different chemical equilibrium constants. Industrial & Engineering Chemistry Research, 43, 2493–2507]. A generic exothermic reversible reaction A + B ↔ C + D occurs in both flowsheets, which consist of a conventional multi-unit reactor/separator/recycle structure and a reactive distillation column. Results showed that the reactive distillation process is significantly less expensive than the conventional process for a wide range of the chemical equilibrium constant when there is no mismatch between the temperature favorable for reaction and the temperature favorable for vapor–liquid separation.

A reactive distillation column has fewer control degrees of freedom than a conventional multi-unit system. Therefore a reactive distillation column may have worse dynamic response than a conventional process. The purpose of this paper is to compare the dynamic controllability of these two alternative processes.

Three different chemical equilibrium constants are considered. Several control structures are developed for each flowsheet, and their effectiveness is evaluated. Disturbances in production rate and fresh feed compositions are considered.

The conventional multi-unit process provides significantly better control. The operability region is much larger, there is less variability in product quality and the dynamic responses are faster than those of the reactive column. Thus, these results demonstrate that there is a significant trade-off in this system between optimum economic steady-state design and dynamic controllability.     

反应冷凝和蒸发模型及其在反应精馏中的应用

为考察反应精馏过程中反应和分离间的耦合现象,建立了连续反应冷凝和反应蒸发模型。通过利用该模型对甲基叔戊基醚(TAME)合成反应精馏过程,考察了惰性组分的存在与不存在2种情况下,不同反应强度Da数对该过程的影响。指出了该反应精馏过程合理的塔结构形式、合适的反应强度范围、甲醇的过量程度以及产物组成状况。     

Towards further internal heat integration in design of reactive distillation columns—Part II. The process dynamics and operation

In the first paper of this series, it has been demonstrated that the capital investment and operating cost can frequently be reduced substantially through seeking further internal heat integration between the reaction operation and separation operation for a reactive distillation column involving reactions with highly thermal effect. In this paper, the dynamics and operation of the resultant reactive distillation system is to be examined, with special emphasis focused on the dynamic effect of the supplementary internal heat integration. It has been found that seeking further internal heat integration can sometimes improve process dynamics and lessen difficulties in process operation. This outcome stems from the refined relationship between the reaction operation and separation operation involved and is of great significance in tightening process design for a reactive distillation column containing reactions with highly thermal effect.It should, however, be pointed out that seeking further internal heat integration might also confine severely the flexibility of the resultant reactive distillation column due to the reduction of mass transfer driving forces. When encountering a sharp increase in the product specification that is more relevant to the supplementary internal heat integration, the process might show deteriorated dynamic performance and can even converge to an undesirable steady state where the economical advantages of the supplementary internal heat integration are lost totally. Therefore, some effective measures to increase the redundancy of the resultant process design have to be taken to deal with the side-effect during process development.     

Simulation studies on reactive distillation for synthesis oftert-amyl ethyl ether

In this work, a reactive distillation column in which chemical reactions and separations occur simultaneously is applied for the synthesis of tert-amyl ethyl ether (TAEE) from ethanol (EtOH) and tert-amyl alcohol (TAA). A rate-based kinetic model for liquid-phase etherification and an equilibrium stage model for separation are employed to study the reactive distillation. The calculation is carried out using the commercial software package, Aspen Plus. Simulations are performed to examine the effects of design variables, i.e., a number of rectifying, reaction and stripping stages on the performance of reactive distillation column. It has been found that an optimal column configuration for the TAEE production under the study is designed with no rectifying, 4 reaction and 8 stripping stages. With such an appropriate specification of the reactive distillation column, the effects of various operating variables on the TAA conversion and TAEE selectivity are further investigated and the results have shown that the reflux ratio and operating pressure are the most important factors to the operation of the reactive distillation.     

Design and control of reactive distillation for hydrolysis of methyl lactate

Esterification of raw lactic acid from fermentation broth and then hydrolysis of lactate ester in reactive distillation column is an effective process for purification of lactic acid. Reactive distillation for hydrolysis of methyl lactate is studied. First, the thermodynamic properties and reaction kinetics are analyzed; then the reactive distillation column is designed based on the objective function total annual cost. The effects of tray number of rectifying section, tray number of reactive section, and feed location on the total annual cost are investigated. And a dual-temperature control structure is proposed for the optimal reactive distillation column, and the results show that it works quite well for this hydrolysis system.     

反应精馏技术的研究现状及应用进展

反应精馏是化学反应和精馏过程耦合为一体的单元操作,已成为当今的重要研究领域。本文对反应精馏技术的研究现状及其应用进行了综述,介绍了反应精馏塔及催化剂,对催化剂床中传质及流体力学特征,数学模型和反应精馏塔设计方程进行了总结;同时介绍了反应精馏技术的应用现状及其可能的应用领域．     

Nonlinear model based control of two-product reactive distillation column

Nonlinear feedback control scheme for reactive distillation column has been proposed. The proposed control scheme is derived in the framework of Nonlinear Internal Model Control. The product compositions and liquid and vapor flow rates in sections of the reactive distillation column are estimated from selected tray temperature measurements by an observer. The control scheme is applied to an example reactive distillation column in which two products are produced in a single column and the reversible reaction A+B=C+D occurs. The relative volatilities are favorable for reactive distillation so that the reactants are intermediate boilers between the light product C and the heavy product D. Ideal physical properties, kinetics, and vapor-liquid equilibrium are also assumed. It is shown that the proposed control scheme keeps tight product composition control.     

外部环流反应精馏塔的分散控制方案设计

对于具有最不利相对挥发度排序（即反应物为最轻和最重组分，生成物为中间组分）的四元反应分离物系而言，在反应精馏塔的顶部和底部之间引入外部环流能够提高系统的反应分离效率，从而大幅度地降低系统的能量消耗和固定投资成本。以理想四元可逆放热反应的分离为例，研究了外部环流反应精馏塔的分散控制方案的设计问题。结果表明外部环流的引入提高了系统的反应速率，使得外部环流反应精馏塔的闭环控制效果更好（与传统反应精馏塔相比），对干扰的处理能力更强。另外，由于外部环流反应精馏塔比常规反应精馏塔有更多的操作变量（即外部环流流量），利用该变量对出料浓度进行控制，可以进一步提高系统的闭环控制效果。     

基于(火用)损失分析的反应精馏塔板上反应体积的优化设计

针对以选择性为主要目标的反应精馏塔设计中反应段塔板上反应体积或催化剂的分配问题,提出一种基于热力学(火用)损失分析和流程模拟计算相结合的优化设计策略。为了深层次分析反应精馏塔板上(火用)损失的原因并为制定调优方向提供理论依据,将塔板上的总(火用)损失区分为物理(火用)损失和化学(火用)损失两部分并分别进行计算。在此基础上,将建立的(火用)损失计算方法和流程模拟技术相结合,将反应段塔板上的反应体积的分配和对应的(火用)损失分布相关联,以再沸器热负荷最小为目标,通过建立的方法对反应体积的分配逐步调优,可实现反应精馏塔的优化设计。方法的有效性通过环氧乙烷水合制乙二醇反应精馏体系进行了验证。结果表明,与普遍采用的塔板上等反应体积分配的设计方法相比,通过本文建立的优化分配方法,可使系统的能耗降低18%以上,同时结果优于文献值。     

反应精馏隔壁塔生产乙酸正丁酯的优化与控制

对反应精馏隔壁塔生产乙酸正丁酯过程进行了模拟、优化与控制的系统研究。利用Aspen Plus软件模拟乙酸甲酯与正丁醇的酯交换反应过程,以年总费用（TAC）为目标函数进行过程优化,通过稳态敏感性分析及相对增益矩阵（RGA）判据得到不同的操纵变量与控制变量匹配关系,以此为基础,在Aspen Dynamics平台建立了若干控制结构并进行分析对比。结果表明,利用两股反应物呈比例进料可较为有效地抵抗进料扰动,最后提出的无再沸器热负荷与混合物进料量比值（Q_r/F）控制的改进控制结构CS3,在降低反应精馏隔壁塔控制过程超调量方面有较大的优越性。