特殊精馏热耦合强化技术研究进展

在石油、医药、化工等行业生产和分离过程中,常伴随着共沸或沸点相近混合物的产生,其高效节能分离是工业清洁生产和可持续发展的前提。作为一种分离共沸或近沸等难分离混合物的重要手段,特殊精馏引起了广泛关注。然而,特殊精馏对能源的消耗量非常大,开发低成本、性能可靠的特殊精馏强化技术对实现经济和能源的可持续发展具有重要意义。基于对特殊精馏塔内外传质传热规律的研究,本文从强化原理和工艺改进技术两方面,重点介绍了热耦精馏、隔壁塔、侧线精馏、有机朗肯循环、热泵精馏、差压热耦合等内外热耦合强化技术在特殊精馏节能增效等方面的研究进展,并展望了其未来发展的挑战和机遇,以期为特殊精馏在热耦合强化方面的理论研究与应用提供参考。     

Distillation technology – still young and full of breakthrough opportunities

Throughout history, distillation has been the most widespread separation method. However, despite its simplicity and flexibility, distillation still remains very energy inefficient. Novel distillation concepts based on process intensification, can deliver major benefits, not just in terms of significantly lower energy use, but also in reducing capital investment and improving eco‐efficiency. While very likely to remain the separation technology of choice for the next decades, there is no doubt that distillation technology needs to make radical changes in order to meet the demands of the energy‐conscious modern society. This article aims to show that in spite of its long age, distillation technology is still young and full of breakthrough opportunities. Moreover, it provides a broad overview of the recent developments in distillation based on process intensification principles, for example heat pump assisted distillation (e.g. vapor compression or compression–resorption), heat‐integrated distillation column, membrane distillation, HiGee distillation, cyclic distillation, thermally coupled distillation systems (Petlyuk), dividing‐wall column, and reactive distillation. These developments as well as the future perspectives of distillation are discussed in the context of changes towards a more energy efficient and sustainable chemical process industry. Several key examples are also included to illustrate the astonishing potential of these new distillation concepts to significantly reduce the capital and operating cost at industrial scale. © 2013 Society of Chemical Industry     

裂解C_5馏分分离技术的研究进展

简要介绍了C5馏分的用途以及国内外C5馏分分离技术的研究进展,叙述了几种主要分离工艺流程的特点和近年来开发的一些新技术,如在节能降耗和提高经济效益方面具有很大潜力的热耦精馏、热集成、化学吸收及膜分离等方法,展望了C5馏分分离技术在工艺优化、节能、开发新型萃取溶剂等方面的前景。     

Reduction of Energy Consumption and Greenhouse Gas Emissions in a Plant for the Separation of Amines

The chemical industry comprises of the companies that produce industrial chemicals. It is central to the modern world economy, converting raw materials into more than 70 000 different products. However, environmental regulations and the risk of climate change are putting pressure on the chemical industry to minimize greenhouse gas emissions. In this work, we use the concept of process intensification (using thermally coupled distillation) to reduce energy consumption and CO₂ emissions in a plant for the separation of amines. The results show that the use of thermally coupled distillation sequences can be related to a reduction in energy consumption, greenhouse gas emissions, and good theoretical control properties in the re‐designed plant.     

精馏技术研究进展与工业应用

精馏是化学工业中应用最广泛的关键共性技术,广泛应用于石油、化工、化肥、制药、环境保护等行业。精馏具有应用广泛、技术成熟等优点,但存在设备投资大、分离能耗高等问题,因此研究开发新型高效传质元件、开发新型节能精馏技术,具有重要的社会意义和经济价值。本文从精馏塔类型、流体力学性能、传质性能、塔器大型化、过程节能、过程强化等方面,介绍了精馏技术的研究进展与工业应用。对于板式塔,从气液两相流动状态、压降、漏液和雾沫夹带方面研究了塔板的流体力学性能;对于填料塔,从压降、液泛和持液量方面研究了填料塔的流体力学性能,但目前的研究仍以经验关联式为主,缺乏严谨的的理论模型。对于气液两相的传质性能研究,简述了气液两相传质理论,但科学、精准的传质模型尚未提出。对于塔器大型化的应用研究,介绍了塔板、气液分布器和支撑装置等大型化关键技术的工业应用。从精馏过程典型节能技术、耦合节能技术、流程节能技术、低温余热回收和特殊精馏等方面,介绍了精馏过程节能与强化的应用进展。文章最后对精馏过程的传质、强化和集成进行了展望。     

丁二烯分离装置热偶精馏的操作特性

以丁二烯分离装置为对象，对热偶精馏ＴＣＳ－Ｒ用于非理想体系的操作特性和节能效果进行了模拟分析与研究。根据分离要求确定主塔最小馏出的液量后，热偶精馏ＴＣＳ－Ｒ的分离能力和节能效果受汽相连接流股流率的影响最大，其次为汽相连接流股的抽出位置。丁二烯分离装置中应用热偶精馏ＴＣＳ－Ｒ后可以在满足分离要求的前提下节能４０％左右。在此基础上，对这种偶合塔计算了主塔底乙烯基乙炔含量变化对汽相连接流率变化的灵敏度。     

Feasibility study of a thermally coupled reactive distillation process for biodiesel production

Biodiesel fuel represents an interesting alternative as a clean and renewable substitute of fossil fuels. A typical biodiesel production process involves the use of a catalyst, which implies high energy consumptions for the separation of the catalyst and the by-products of the reaction, including those of undesirable side reactions (such as the saponification reaction). A recently proposed process involves the use of short-chain alcohols at supercritical conditions, avoiding the use of a catalyst and the occurrence of the saponification reaction. This process requires fewer pieces of equipment than the conventional one, but its high energy requirements and the need of special materials that support the reaction conditions makes the main product, biodiesel fuel, more expensive than petroleum diesel. In this work, a modification of the supercritical process for the production of biodiesel fuel is proposed. Two alternatives are proposed. The process involves the use of either reactive distillation or thermally coupled reactive distillation. Simulations have been carried out by using the Aspen One™ process simulator to demonstrate the feasibility of such alternatives to produce biodiesel with methanol at high pressure conditions. A design method for the thermally coupled system is also proposed. Both systems have been tested and the results indicate favorable energy performance when compared to the original scheme. Furthermore, the thermally coupled system shows lower energy consumptions than the reactive distillation column.     

内部热耦合空分塔的节能优化分析

内部热耦合精馏是迄今为止所提出的节能效果最好,而唯一没有商业化的节能技术。将内部热耦合技术用于空分塔,可以带来良好的节能效果。根据低温空气分离过程以及三组分精馏的特点,提出了一种新的内部热耦合空分精馏塔优化模型。在优化模型基础上,对热耦合塔进行了深入的节能优化与分析,并且与常规空分仿真结果进行了比较分析,压缩机能耗下降20.75%,产值增加17.46%,单位产值能耗下降32.53%。内部热耦合空分塔的提取率以及能耗均优于常规热耦合空分塔,节能效果显著。     

Effect of Recycle Streams on the Closed-Loop Dynamics of Thermally Coupled Distillation Sequences

The effects of thermal links on the closed-loop dynamics of thermally coupled distillation sequences for the separation of quaternary mixtures have been studied in this work by using rigorous dynamic simulations. The incorporation of thermal links into conventional distillation sequences can lower the energy consumption up to 40% without introducing additional control problems to the resulting thermally coupled distillation sequences. In some cases, the thermally coupled distillation sequences outperformed the dynamic behavior of the conventional distillation sequences for set point tracking. This result is important to establish that thermally coupled distillation sequences not only can have significant energy savings but also good dynamic properties.     

A review on process intensification in internally heat-integrated distillation columns

Internally heat-integrated distillation column (HIDiC) is the most radical approach of a heat pump design, making efficient use of internal heat-integration: the rectifying section of a distillation column operating at a higher pressure becomes the heat source, while the stripping part of the column acts as a heat sink. Remarkably, a HIDIC can bring up to 70% energy savings compared to conventional distillation columns. This is highly appealing regarding the fact that distillation is one of the most energy intensive operations in the chemical process industry accounting for over 40% of the energy usage. This review paper describes the latest developments concerning this promising but difficult to implement process intensification technology, covering all the major aspects related to the working principle, thermodynamic analysis, potential energy savings, various design configurations and construction options (ranging from inter-coupled or concentric columns, shell and tube and plate–fin heat exchanger columns to SuperHIDiC), design optimization, process control and operation issues, as well as pilot-scale and potential industrial applications. Further advancement, i.e., development of HIDiC technology for multi-component mixture separations is an extremely challenging research topic, especially when HIDiC becomes associated with other technologies such as dividing-wall column (DWC) or reactive distillation (RD).     

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。     

An industrial perspective on membrane distillation processes

Process intensification has led to significant developments in both distillation and membrane technology. Membrane distillation (MD) is an emerging technology for fluid separations that are typically performed by conventional separation processes, such as distillation or reverse osmosis (e.g. water desalination, or water removal). Compared with other membrane technologies, the driving force in MD is the difference in vapor pressure across the hydrophobic membrane, rather than the total pressure. MD can be a cost effective separation process, especially when more sustainable alternative sources of energy (e.g. geothermal and solar) or waste heat sources are used. Many review papers on MD are available in the open literature, but most of them focus on the membrane characteristics (e.g. material aspects). This industrial perspective paper assesses the MD technology and reports on relevant issues by offering a concise overview of MD technology, addressing different MD configurations, current major applications, operating parameters and their effect on the MD process, commercially available membranes, as well as cost estimations to determine the feasibility of MD processes. While successfully applied in desalination and a few other niche applications, MD has failed to make a strong industrial impact in other areas still dominated by distillation. A key message is that membrane distillation is still a growing technology for separation and purification processes, but it needs further exploration and optimization to become a mature technology applicable to more industrial processes in the chemical process industry. © 2018 Society of Chemical Industry     

生物乙醇原位分离技术的研究进展

生物乙醇是一种重要的可再生生物燃料,使用生物乙醇可大幅减少温室气体排放。为了建立更高效低能耗的生物乙醇回收工艺,原位分离（ISPR）技术应运而生。本文综述了近年来乙醇原位分离的研究进展,从原理及应用等进行多方面详细地介绍,包括气提、真空发酵、吸附、液-液萃取、渗透汽化、膜蒸馏等分离技术。针对分离性能、能耗成本等问题分析了不同分离技术耦合发酵过程的优势及不足,重点回顾了以渗透汽化为代表的膜分离技术,总结了渗透汽化膜材料的选择以及膜的制备方法,旨在提升乙醇分离膜性能优化乙醇分离工艺。为整合不同分离技术的特点及优势,聚焦多级耦合分离系统的开发对各级分离技术联用的性能及潜力进行剖析与评价,并在此基础上研判其发展前景。     

Hybrid Distillation/Melt Crystallization Process Using Thermally Coupled Arrangements: Optimization with evolutive algorithms

Innovative hybrid processes offer significant cost savings, particularly for azeotropic or close-boiling mixtures. Hybrid separation processes are characterized by the combination of two or more different unit operations, which contribute to the separation task by different physical separation principles. Despite of the inherent advantages of hybrid separation processes, they are not systematically exploited in industrial applications due to the complexity of the design and optimization of these highly integrated processes. In this work we study a hybrid distillation/melt crystallization process, using conventional and thermally coupled distillation sequences. The design and optimization were carried out using, as a design tool, a multi-objective genetic algorithm with restrictions coupled with the process simulator Aspen Plus™, for the evaluation of the objective function. The results show that this hybrid configuration with thermally coupled arrangements is a feasible option in terms of energy savings, capital investment and control properties.     

液化天然气分离的节能蒸馏工艺

采用严格模拟计算的方法,对液化天然气分离过程的现有常规蒸馏工艺与热耦蒸馏工艺、侧线提馏工艺、双效蒸馏工艺和热集成工艺进行了模拟,并比较了其能量消耗。模拟计算结果显示,复杂蒸馏工艺都比常规蒸馏工艺减少了能耗和操作成本。其中,热耦蒸馏工艺可比常规蒸馏工艺节能21.4%,侧线提馏工艺节约13.3%,双效蒸馏工艺可节约34.7%,热集成工艺节约则达37.6%左右,表明新工艺在此分离过程中都有较好的应用前景,尤以多效蒸馏和热耦蒸馏最有优势。     

膜蒸馏技术研究及应用进展

膜蒸馏作为一种新型分离技术,具有操作温度低、设备简单、脱盐率高等特点,在海水淡化、苦咸水脱盐、果汁浓缩等过程具有良好的应用前景。本文简述了膜蒸馏的工作原理、特点和膜材料的制备方法,指出当前膜材料的研究方向。综述了直接接触式、气隙式、真空式和气扫式4种基本膜蒸馏形式和几种改进的膜蒸馏形式的传热传质原理、研究现状和发展方向。重点介绍了可再生能源以及工业低温余热驱动膜蒸馏的技术特点、研究现状和应用,包括太阳能光伏/光热驱动膜蒸馏技术、太阳能热泵耦合驱动膜蒸馏技术、太阳池膜蒸馏技术、地热能梯级利用驱动膜蒸馏技术和低温余热驱动膜蒸馏技术等,并指出其发展方向。最后,探讨了膜蒸馏技术亟待研究和解决的问题,为该技术的进一步发展提供参考。     

蒸馏过程强化技术研究进展

蒸馏过程强化技术作为我国现代化学工业发展的重要研究领域,是过程强化概念在化学工业成功应用的典范之一。随着近些年的发展,蒸馏过程强化技术的研究已形成了一套较完整的体系,但也出现了一系列新的难题与挑战。为此,本文针对混合物相对挥发度与气液传质两个蒸馏过程强化的基础理论本质问题,以基础理论创新、关键技术突破和关键装备研究进展为主线,从强化原理、研究进展、工业应用及发展3方面系统介绍共沸蒸馏、萃取蒸馏、反应蒸馏这3类典型的引入质量分离剂强化的蒸馏过程及其耦合技术;微波、超重力场等典型外场作用下的引入能量分离剂强化的蒸馏过程,并系统介绍以新型塔内件及新型塔结构为切入点的基于先进设备强化的蒸馏过程,为迎接这一领域新的难题和挑战提供新思路。     

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.     

Esterification of fatty acids in a thermally coupled reactive distillation column by the two-step supercritical methanol method

Biodiesel fuel has been shown as a clean energy alternative to petroleum diesel. Conventional biodiesel production involves the use of catalyst, which implies high energy consumptions for the separation of both the catalyst and the by-products of the reaction, including those of the undesirable reaction of saponification. Recently, a process involving the use of short-chain alcohols at supercritical conditions has been proposed (Saka-Dadan process); one of the main advantages of that process is that it avoids the need for a catalyst as well as the occurrence of the saponification reaction. However, although the process requires less pieces of equipment than the conventional one, its energy requirements are still high, making biodiesel fuel more expensive than petroleum diesel. This work proposes the use of reactive distillation and thermally coupled reactive distillation configurations to produce biodiesel fuel by the supercritical methanol method. First-order kinetics is used to represent the esterification reaction, obtaining high conversions in a single shell. Both of the configurations proposed reduce energy requirements when compared to the conventional (Saka-Dadan) process. Calculations were also performed to estimate CO₂ emissions, thermodynamic efficiency and cost. The thermally coupled reactive distillation configuration shows to be the best alternative in terms of energy consumption, CO₂ emissions and thermodynamic efficiency. Further, cost estimations also show that the use of a thermally coupled scheme considerably reduces both utilities and capital costs.