Novel Control Structure Design of Differential Pressure Thermally Coupled Reactive Distillation for Methyl Acetate Hydrolysis

In this paper, the novel control structures of differential pressure thermally coupled reactive distillation process for methyl acetate hydrolysis were proposed. The RadFrac module of Aspen Plus was adopted in the steady-state simulation. Sensitive analysis was applied to find the stable intial value and provide a basis for the improved control structure design. The Aspen Dynamics software was adopted to study the process dynamic behaviors, and two novel control structures provided with feed ratio controllers and sensitive tray temperature controllers were proposed. The reflux ratio controllers were applied in the improved novel control structures. Both control structures abandoned the composition controllers that were replaced by simpler controllers with which the product purity could meet the specification requiring under a ± 20% disturbance to the total feed flowrate / MeAc composition.

Design and Control of Thermally Coupled Reactive Distillation Sequence for Biodiesel Production

Decreasing petroleum reserves and growing alternative fuels requirements have promoted the study of biodiesel production. In this work, two thermally coupled reactive distillation designs for biodiesel production were investigated, and the sensitivity analysis was conducted to obtain the appropriate design values. The thermodynamic analysis and economics evaluation were performed to estimate the superiority of the thermally coupled designs over the base case. The proposed biodiesel production processes were simulated using the simulator Aspen Plus, and calculation results show that the exergy loss and economic cost in the two thermally coupled designs can be greatly reduced. It is found that the thermally coupled side-stripper reactive distillation design provides more economic benefits than the side-rectifier one. The dynamic performance of the thermally coupled side-stripper design was investigated and the results showed that the proposed control structure could effectively handle large feed disturbances.

A Novel Thermally Coupled Reactive Distillation Column for the Hydrolysis of Methyl Acetate

A different pressure thermally coupled reactive distillation column(DPT-RD) for the hydrolysis of methyl acetate(Me Ac) is developed, and its design and optimization procedures are investigated. The sensitivity analysis is carried out to minimize the energy consumption, which is associated with the total annual cost(TAC). The influence of the proposed DPTRD scheme on energy consumption and economic efficiency are evaluated in comparison with the conventional reactive distillation column(CRD). Both the DPT-RD and CRD are simulated with the Aspen Plus?, and it can be observed that for the DPT-RD the energy consumption and the TAC are reduced, and the thermodynamic efficiency is increased as compared with the CRD process.

Process intensification and energy saving of reactive distillation for production of ester compounds

Reactive distillation(RD) process is an innovative hybrid process combining reaction with distillation, which has recently come into sharp focus as a successful case of process intensification. Considered as the most representative case of process intensification, it has been applied for many productions, especially for production of ester compounds. However, such problems existing in the RD system for ester productions are still hard to solve,as the removal of the water which comes from the esterification, and the separation of the azeotropes of ester–alcohol(–water). Many methods have been studying on the process to solve the problems resulting in further intensification and energy saving. In this paper, azeotropic–reactive distillation or entrainer enhanced reactive distillation(ERD) process, reactive extractive distillation(RED) process, the method of co-production in RD process, pressure-swing reactive distillation(PSRD) process, reactive distillation–pervaporation coupled process(RD–PV), are introduced to solve the problems above, so the product(s) can be separated efficiently and the chemical equilibrium can be shifted. Dividing-wall column(DWC) structure and novel methods of loading catalyst are also introduced as the measures to intensify the process and save energy.

催化重整过程苯-甲苯分离体系的模拟与优化

针对催化重整装置中的苯-甲苯分离体系能量利用率低的问题,采用差压热耦合精馏技术及热泵精馏技术提高体系的能量利用率,并在差压热耦合精馏单元与热泵精馏单元之间进行热集成,充分利用体系中的余热。应用Aspen HYSYS V11流程模拟软件对优化前后的模型进行模拟计算和分析。模拟结果表明,在产品纯度和收率相同的条件下,采用热泵精馏、差压热耦合精馏和热集成3种节能技术的工艺与原工艺相比可使苯-甲苯分离体系能量节约23.33%。

差压热耦合蒸馏节能技术

开发了一种广泛适用于蒸馏分离过程的新型差压热耦合蒸馏技术,该技术将精馏塔分割为两个压力不同的塔,利用高压塔顶蒸汽作为低压塔底的热源,实现热能的耦合匹配,达到蒸馏过程大幅度节能的目的。利用计算机模拟方法对该技术应用在丙烯-丙烷分离和混合C4分离过程中的节能效果进行了计算和分析,结果表明与现有常规蒸馏过程相比,差压热耦合低能耗蒸馏过程能耗可以分别降低92.3%和87.1%,节能效果显著。

多晶硅生产中三氯氢硅精馏节能工艺

简述了多晶硅行业概况和差压耦合蒸馏节能技术。详述了一种高纯三氯氢硅差压耦合精馏工艺,利用高压塔塔顶蒸汽作为低压塔塔釜再沸器热源,实现了能量的集成与过程优化。运用化工模拟软件PRO/Ⅱ8.1模拟了两塔高纯三氯氢硅差压耦合精馏工艺和三塔高纯三氯氢硅差压耦合精馏工艺的设计参数。结果显示,两塔耦合三氯氢硅一次收率为92.0%,理论节能50.1%;三塔耦合三氯氢硅一次收率为92.0%,理论节能66.7%,效果更好。该技术已成功实现工业化,可使精馏单元实际能耗平均降低40%～60%,同时大幅减少了设备投资。

差压热耦合精馏回收处理含二甲基乙酰胺废水的工艺研究

采用差压热耦合精馏工艺对含二甲基乙酰胺(DMAC)的废水进行回收处理。利用ASPEN PLUS过程模拟软件中的RADFRAC严格精馏计算模型,采用NRTL-RK方程计算气液相平衡数据,对单塔精馏工艺进行模拟。在此基础上,对提出的差压热耦合精馏工艺进行过程模拟与参数优化,得到了差压热耦合精馏处理含DMAC废水的最佳工艺参数、塔内气液浓度分布、精馏塔设备参数等。模拟结果表明,差压热耦合精馏工艺比常规的单塔精馏工艺节能约73.4%。

反应精馏应用于差压热耦合精馏技术的模拟

将差压热耦合反应精馏塔应用于乙酸甲酯的合成,利用Aspen Plus软件建立了模型并进行了流程模拟。对提出的工艺进行了单变量分析,进一步确定了各个变量的最佳值。在此基础上,对差压热耦合反应精馏流程的能耗、CO_2排放量方面与常规反应精馏流程进行了全面的分析与比较。结果表明,与传统流程相比,差压热耦合流程可节能达58.79%,并有很好的减排效果。

一种改进的差压热耦合精馏流程

为深入研究差压热耦合精馏的节能特性,进而得到节能效果更佳的改进差压热耦合精馏流程,引入中间冷却器,提出了一种改进的差压热耦合精馏流程。以甲基环戊烷/苯二元物系为例,以标准煤能耗计算为基准,对改进前后2种流程的节能效果进行比较,考察了中间冷却器负荷变化对其热耦合程度的影响,以及进料温度对改进流程能耗的影响;通过对差压热耦合工艺系统分析,建立了差压热耦合精馏的一般通用模型,系统地考察了差压热耦合精馏3种典型的操作状态。结果表明,相对于原差压热耦合精馏流程,改进的差压热耦合精馏流程的节能效率达3.50%,并得到了两塔热量完全耦合时的中间冷却器负荷。

差压热耦合萃取精馏工艺分离甲基环己烷和甲苯的模拟研究

以苯酚为萃取剂,采用萃取精馏对甲基环己烷(MCH)-甲苯(MB)物系进行分离,比较了常规萃取精馏工艺流程和差压热耦合萃取精馏工艺流程;采用Aspen Plus化工流程模拟软件对萃取精馏工艺分离MCH-MB物系进行了模拟计算,考察了差压热耦合萃取精馏工艺中萃取剂进料位置、原料进料位置、萃取剂与原料的摩尔比(溶剂比)、回流比和压缩比等参数对MCH产品纯度及工艺能耗的影响。模拟得到差压热耦合萃取精馏塔优化的操作参数:萃取剂进料位置为第6块理论板,原料进料位置为第4块理论板,溶剂比为2.95,回流比为6,压缩比为12。模拟结果表明,差压热耦合萃取精馏工艺节能效果显著,比常规萃取精馏工艺可节能74.97%,得到MCH产品的含量可达99.54%(x)。

差压热耦合精馏分离甲基环戊烷/苯过程的动态性能研究

以环戊烷/苯二元物系为例,采用动态模拟软件Aspen Plus Dynamics,对差压热耦合精馏的动态控制性能进行研究与分析。根据其工艺流程特点与分离操作要求建立了一种合理的控制方案。同时,对进料的流量、温度和组成扰动进行分析,考察塔顶、塔釜产品组成和流量等对进料扰动的闭环响应特性,分析该控制方案下差压热耦合精馏工艺对不同干扰因素的抗干扰性能和动态稳定特性。结果显示,该流程动态可控性强,各指标均能在干扰施加后较短时间内达到稳定,对各项干扰的稳定性能良好。

高纯三氯氢硅精馏节能工艺的模拟分析

针对多晶硅生产中高纯三氯氢硅精馏提纯过程能耗较高的特点,分别将热泵和差压热耦合精馏节能工艺应用到高纯三氯氢硅精馏提纯过程中,并使用Aspen Plus软件对这2种节能工艺进行模拟分析比较,计算得到各工艺流程的能耗,实现了过程的节能和优化。模拟结果表明,热泵和差压热耦合精馏节能工艺对三氯氢硅传统二塔精馏过程均起到了显著的节能效果,其中塔顶蒸汽压缩型、塔釜液闪蒸型热泵精馏过程分别节能66.1%、62.8%,差压热耦合精馏过程节能50.1%。

内部热耦合反应精馏塔塔构型的研究

以乙酸甲酯水解为例,利用模拟软件Aspen Plus建立了内部热耦合反应精馏塔模型,研究了内部热耦合反应精馏塔各种可能塔构型的节能效果,并且在相同的产品要求和最小传热温差下对内部热耦合反应精馏塔各构型的能耗进行了对比。结果表明,塔构型对乙酸甲酯水解的内部热耦合反应精馏流程的操作性能有重要的影响,并且存在最佳构型。其最佳构型的特征为,反应段全部在内部热耦合反应精馏塔的精馏塔内且精馏塔与提馏塔中理论板均参与传热的塔构型。

差压热耦合反应精馏塔的模拟研究

为了降低反应精馏塔能耗,将差压热耦合技术与反应精馏技术结合,提出了一种新型的差压热耦合反应精馏的流程,并将其应用于乙酸正丁酯的合成中。应用Aspen Plus模拟软件对新工艺流程以及常规反应精馏流程进行了模拟,通过考察压缩比、进料位置、进料醇酸摩尔比等因素对差压热耦合反应精馏合成乙酸正丁酯工艺的影响,得到最优条件。同时,将该工艺与常规反应精馏工艺进行比较,结果显示,新工艺能够大幅度降低能耗,与常规反应精馏装置相比可节能40%左右。

丙烯差压热耦合精馏塔动态模拟与控制

以炼厂气体分馏装置丙烯精馏为例,利用Aspen Plus建立差压热耦合精馏稳态模拟,在此基础上运用Aspen Dynamics对RR-BR控制方案和D-B控制方案的动态特性进行研究,并与常规精馏进行比较。结果表明,该系统没有因为热耦技术的引入而使其对抗进料量和组成干扰的动态性能变差,RR-BR控制方案控制质量要优于D-B控制方案,主换热器的换热负荷和换热面积是差压热耦合精馏系统关键。

差压热耦合反应精馏应用于乙酸甲酯水解研究

结合差压热耦合和反应精馏工艺优势,提出形成差压热耦合反应的精馏工艺方法,将其应用于乙酸甲酯水解过程。在验证UNIQ-HOC模型对模拟该体系适用性的基础上,对影响该工艺的主要影响因素进行考察,得出优化后的主要操作参数,并对比差压热耦合精馏和常规流程的能耗。结果表明,差压热耦合反应精馏增加813.33 kW的功耗,减少7062.3 kW的热量,节能效果显著。

一种用于多晶硅的无关联塔差压热耦合技术

本文提供了一种多晶硅精馏提纯无关联塔之间的差压热耦合技术。该技术可以是两塔或三塔,各塔各自有进料、塔顶采出、塔底采出,物料之间无任何关系,实现了不同塔组不同塔之间的塔差压热耦合,扩大了常规差压热耦合的使用范围。

热泵与差压热耦合精馏系统模拟优化与控制方案设计

以炼厂气体分馏装置丙烯精馏为例,利用Aspen Plus建立精馏稳态模拟,计算了压缩机功耗;并在分析各影响系统功耗因素的基础上,对系统进行了优化;进一步运用Aspen Dynamics对D-B和RR-BR控制方案的动态特性进行了研究。结果表明,差压热耦合精馏流程由于降低了低压塔的气液相负荷故压缩机功耗较小,A、B型热泵精馏流程通过增加膨胀阀前过冷度使功耗明显降低;B型热泵精馏塔顶塔底耦合度较小,动态性能较好;差压热耦合精馏塔顶塔底耦合度与B型热泵精馏相仿,对控制塔顶产品质量也具有优势,但在塔底产品质量控制上相对较差;A型热泵精馏流程在控制过程中出现了不稳定现象。

醋酸戊酯差压热耦合反应精馏过程的节能优化

为了实现醋酸戊酯反应精馏系统反应-分离-能量集成的优化设计,建立了差压热耦合反应精馏(DPTRD)新工艺。采用Aspen软件对DPT-RD流程进行模拟,考察了塔板持液量、降压分馏塔压力、HAc进料位置、两塔耦合方式等对DPT-RD过程的影响。结果表明,在塔板持液量为0.25m3、降压分馏塔压力为0.16bar、HAc第6块板进料、常规分馏塔塔板数为24的最优条件下,DPT-RD比常规反应精馏节能约78.22%,节能效果显著。