乙烯精馏塔模拟分析与运用

乙烯精馏塔分离出产品乙烯,该塔控制的好坏直接影响乙烯产品质量和回收率,利用Aspen Plus模拟软件对乙烯装置的乙烯精馏塔进行了分析,确定了乙烯精馏塔进料塔板、灵敏板位置,并通过灵敏度分析得到各工艺参数对乙烯产品规格的影响.通过模拟指导,乙烯精馏塔增加灵敏板温度控制,塔釜液位控制,优化乙烯精馏塔压与回流量的控制,实现...     

MTBE装置的全流程模拟与优化

采用Aspen Plus软件,对MTBE(甲基叔丁基醚)装置进行了全流程模拟,模拟结果与实际值吻合良好。在此基础上,考察了工艺参数对催化精馏塔、萃取塔和甲醇回收塔影响,得到了优化的工艺参数:醇烯比为1.5,催化精馏塔回流比为1.05,萃取塔溶剂比为0.21,甲醇回收塔塔顶采出率为0.107,甲醇回收塔回流比为5。通过工艺参数优化,MTBE产品质量分数达98.8%,MTBE回收率达99.71%,异丁烯转化率达98.52%,催化精馏塔和甲醇回收塔的总热负荷可降低7.4%。     

甲醇精馏塔静态模型分析与仿真设计

以甲醇精馏四塔双效工艺流程为研究对象,基于物料平衡和能量守恒,分析影响甲醇精馏的过程参数,并将甲醇精馏过程分塔顶、塔板、塔釜、再沸器、冷凝器等几部分,分别对其进行静态数学模型的构建。分别使用Kingview和Aspen plus在进料量温度为45℃、55℃下进行静态仿真。运行的数据结果相差较小,验证了甲醇精馏塔静态模型的准确性,对于精馏过程的分析以及控制的深入研究有一定的意义。     

甲醇三塔精馏工艺设计

介绍了甲醇三塔精馏工艺,并对三塔精馏工艺进行模拟。在满足塔顶甲醇纯度要求的条件下探讨了常压塔塔釜甲醇浓度对塔系热负荷的影响,侧线采出量对塔系热负荷、塔釜杂醇浓度的影响。计算结果可用于甲醇精馏塔的设计及优化。     

ASPEN PLUS在煤制甲醇三塔精馏工艺中的应用

对煤制甲醇的合成产物分离体系进行了研究,应用Aspen Plus化工模拟软件里模型,选用WLSON方程进行物性计算,对甲醇三塔精馏工艺进行了仿真模拟计算。建立并模拟计算了脱醚塔-加压塔-常压塔精馏工艺模型,得到了各个精馏塔的较优的主要工艺参数,为工业设计提供了依据。     

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。     

乙烯装置乙烯精馏塔系统的模拟与优化

通过Aspen Plus软件模拟计算了某乙烯装置1 100 kt/a改扩建前、后乙烯精馏塔系统,针对生产中乙烯精馏塔塔釜乙烯损失较大的问题,从工艺角度分析中沸和再沸换热器热负荷,从设备角度分析乙烯精馏塔的水力学模型。结合现场实际情况提出工艺优化措施,通过降低中沸,提高再沸解决精馏段液泛问题;通过降低冷凝罐(D-410)取液点、或适当提高乙烯制冷压缩机四段出口压力或通过适当降低热流股温度强化相变传热来增加热流股流量,最终满足所需热负荷。     

精馏塔塔釜液位波动原因分析及解决方案

针对脱氢装置脱异丁烷精馏塔塔釜液位波动的现象,分析了液位波动产生的原因,使用Aspen Dynamics进行了动态模拟,找出了液位波动产生的原因,并提出了可行的解决方案。采用该方案后,塔釜液位得到平稳控制。     

PTA装置醋酸脱水塔的动态模拟及控制策略分析

以PTA装置醋酸脱水塔为研究对象,在该醋酸脱水塔的稳态模型的基础上,通过建立的平衡级动态数学模型以及补充设置好的动态参数,利用Aspen Plus软件建立好动态模型。以Aspen Dynamics软件为工具,用回流流量控制灵敏板温度,塔釜再沸器热负荷与进料流量F ₁呈比例控制,模拟设计出了控制策略CS1。又为了保证在进料流量扰动时塔底醋酸浓度更加稳定,利用塔釜再沸器热负荷来控制塔釜醋酸浓度,设计出了控制策略CS2。将两种不同的控制策略对其动态响应进行分析比较,得出在相同目标条件下表现更优的控制策略,为实际生产和控制方案的设计提供方向和指导。     

PTA装置醋酸脱水塔的动态模拟及控制策略分析

以PTA装置醋酸脱水塔为研究对象,在该醋酸脱水塔的稳态模型的基础上,通过建立的平衡级动态数学模型以及补充设置好的动态参数,利用Aspen Plus软件建立好动态模型。以Aspen Dynamics软件为工具,用回流流量控制灵敏板温度,塔釜再沸器热负荷与进料流量F1呈比例控制,模拟设计出了控制策略CS1。又为了保证在进料流量扰动时塔底醋酸浓度更加稳定,利用塔釜再沸器热负荷来控制塔釜醋酸浓度,设计出了控制策略CS2。将两种不同的控制策略对其动态响应进行分析比较,得出在相同目标条件下表现更优的控制策略,为实际生产和控制方案的设计提供方向和指导。     

简化外部热耦合双精馏塔的控制与优化

针对具有3个换热器结构的外部热耦合双精馏塔(S-EHIDDiC),提出了一种新型的控制与优化策略。顶部与底部换热器的热负荷能够改变高压精馏塔的回流量和低压精馏塔的上升汽量,因而可以用来控制高压精馏塔塔顶和低压精馏塔塔底的产品质量。这种控制方法与常规精馏塔的LV控制结构相似。S-EHIDDiC还有多余的决策变量(如进料分流比,高压精馏塔塔压和中间换热器的热负荷),可以对稳态操作进行优化。闭环仿真证明了这种控制结构的可行性,稳态优化也提高了系统的热力学效率。     

面向热集成耦合的精馏过程集成控制与优化

针对具有塔底产品和进料换热热集成的精馏过程，通过机理分析和基于流程模拟软件的仿真分析，说明了再沸热负荷与塔底液位、进料温度等变量的耦合关系，提出了一种面向热集成耦合的集成控制和优化策略，使用再沸热负荷对原料的焓值变化进行补偿，并兼顾塔底液位，保证产品质量合格。集成策略在实际装置上进行了应用研究，解决了塔底产品流量与再沸热负荷之间的协调控制问题。     

间歇提馏塔的操作

A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity. The operation modes of a batch stripping are believed to be the same as those of a rectifier. However, the control system of a stripper is different. In this paper, we explore three different control methods with Hysys (Hyprotech Ltd. 1997) for a batch stripper. The main difference is the control scheme for reboiler liquid level: (a) controlled by reflux flow; (b) controlled by reboiler heat duty; (c)controlled by bottom product flow. The main characteristics of operating a batch stripper with different control scheme are presented in this paper. Guidelines are provided for the startup of a batch stripper, the effects of some control tuning parameters on the column performance are discussed.     

A novel multi-effect methanol distillation process

Crude methanol distillation is an energy-intensive separation process and contributes significantly to the cost of methanol production. Although a number of energy-efficient distillation systems have been proposed, there is potential for energy savings in methanol distillation. To further reduce the energy consumption of methanol distillation, a novel five-column multi-effect distillation process is proposed in this work, which is essentially an improved version of an existing four-column scheme. The four-column scheme is made up of a pre-run column, a higher-pressure column, an atmospheric column and a recovery column. The new five-column scheme adds a medium-pressure column after the original higher-pressure column. In this way, the load of the original higher-pressure and atmospheric columns can be decreased by about 30%. The five-column arrangement creates a multi-effect distillation configuration involving efficient heat integration between higher-pressure and medium-pressure columns, atmospheric and recovery columns, and recovery and pre-run columns. Steady-state process simulation results indicate that temperature differences at two sides of each heat exchanger are appropriate, allowing effective heat transfer. Economic analysis shows that the energy consumption of the five-column scheme can be reduced by 33.6% compared to the four-column scheme. Significant savings in operating costs can therefore be achieved, resulting in an economically viable process for methanol distillation.     

萃取精馏分离苯/环己烷共沸体系的控制策略

将常规萃取精馏、差压热耦合萃取精馏以及隔壁塔萃取精馏技术应用于以糠醛为萃取剂的苯和环己烷共沸物分离过程。在稳态模型的基础上,利用Aspen Dynamics软件进行控制研究,对三工艺流程提出了若干控制策略。结果表明,对于常规萃取精馏过程,再沸器热负荷与进料量比值控制结构在降低控制过程超调量方面表现出明显优势;对于差压热耦合萃取精馏过程,带有压力-补偿控温策略的方案控制效果更佳;而对于隔壁塔,则选择了无隔板下方气液分离比控制的结构来作为较优的控制策略。     

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.     

Argon production from air distillation: Use of a heat pump in a ternary distillation with a side rectifier

A ternary feed mixture ABC can be separated into individual components through the use of a main distillation column with a thermally linked side rectifier. To enhance such a separation, a heat pump can be implemented to transfer heat from the condenser at the top of the side rectifier to the reboiler at the bottom of the main column. In this paper, one such heat pump is described and applied to an air distillation system separating the ternary mixture containing nitrogen, oxygen and argon. The separation is performed by a conventional double column with a crude argon side column. When this system is operated at an elevated pressure to obtain higher product pressures, the separation of oxygen and argon becomes very difficult and leads to reduced argon recovery. The proposed heat pump enhances the separation by providing a supplementary crude argon condensing duty through the vaporization of a liquid oxygen stream from the bottom of the low pressure (LP) column. This scheme improves the liquid/vapour ratio (L/V) in the bottom section of the LP column and, more importantly, increases the vapour feed to the crude argon column. This increased feed rate leads to a substantial increase in argon recovery for the elevated pressure air distillation process.     

甲基氯硅烷精馏流程的模拟与优化

采用Aspen plus软件对工业七塔精馏过程进行全流程建模与模拟,优化工艺参数,研究了新的精馏节能工艺。对一甲塔等7个精馏塔采用双因素水平的灵敏度分析,考察了塔釜采出率、回流比、进料位置和塔顶压力对产品浓度和热负荷的影响,确定一甲塔最优的工艺参数：塔釜摩尔采出率为0.92,摩尔回流比为130,塔顶压力为0.18 MPa,总理论板数为400,在210块理论板位置进料。在此基础上,针对高能耗的脱高塔/脱低塔,模拟研究了双效精馏新工艺,新工艺可节省39.70%的年总成本;针对一甲塔模拟研究了热泵精馏新工艺,新工艺可降低41.42%的年总成本。     

Design and Control of Extraction Distillation for Dehydration of Tetrahydrofuran

Design and control of an extractive distillation system for tetrahydrofuran (THF) dehydration with ethylene glycol as entrainer is investigated. The main module is a two‐column system containing an extractive distillation column, whose top stream is the desired product THF, and an entrainer recovery column. Economic analysis with total annual cost as the objective function is developed. Two kinds of control strategies are explored for THF dehydration. The responses reveal that the control structure with fixed reflux ratio cannot maintain the bottom liquid level of the entrainer recovery column, while the control scheme with fixed reboiler heat duty/feed flow ratio exhibits good control performance in spite of large deviations in feed flow rate and feed composition.     

Design and control of extractive distillation for the separation of methyl acetate-methanol-water

The azeotrope of methyl acetate methanol and water was isolated using extractive distillation with water as entrainer. The pressure-swing extractive distillation (PSED) process and vapor side-stream distillation column (VSDC) with the rectifier process were designed to separate the methyl acetate, methanol and water mixture. It was revealed that the VSDC with the rectifier process had a reduction in energy consumption than the PSED process. Four control schemes of the two process were investigated: Double temperature control scheme (CS1), Q_R/F feedforward control of reboiler duty scheme for PESD (CS2), Q_R/F feedback control scheme for VSDC (CS3), the feedback control scheme of sensitive plate temperature of side-drawing distillation column to dominate the compressor shaft speed (CS4). Feed flow and composition disturbance were used to evaluate the dynamic performance. As a result, CS4 is a preferable choice for separation of methyl acetate-methanol-water mixture. A control scheme combining the operating parameters of dynamic equipment with the control indicators of static equipment was proposed in this paper. It means using the sensitive plate temperature of side-drawing column to control the compressor shaft speed. This is a new control scheme for extractive distillation.