Principles and applications of micro-structured chemical system

介绍了微化工系统是以微米尺度微结构化工装备为核心的化工系统,是实现化工过程绿色、安全、高效的重要途径之一。阐述了微化工系统基于微尺度下流动可控以及混合传递高效的特点,可以有效地提高反应和分离过程的表观速率,大幅度缩小装备尺寸,提高过程的安全性。指出了近年来微化工系统在材料可控制备、新型测试技术和反应分离强化等方面发展迅速,与传统化工系统相比,微化工系统在诸多领域中显现出了优势。     

Prozeßentwicklung: Von der Exergieanalyse bis zur EDV-gestützten Optimierung

Process development: From exergy analysis to computer-aided optimisation. In processes in which chemical compositions or states are altered, limiting case analyses based on the first and second laws of thermodynamics are often of use during preliminary process analyses. Since the introduction of computers for process calculations exergy analyses can be carried out in a simple way and weak points in initial designs in the sense of the second law conveniently located. It is also possible to use exergy analyses to make product predictions if transferable practical exergy losses are available from past experience. In low temperature and energy technology the use of suitably defined efficiencies have been of use for many years in eliminating less attractive processing routes and thus reducing the number of possible designs to be investigated. For many decades so-called ?Sum Q/T Diagrams”? have been used in low temperature processing to visualize and improve temperature profiles in heat exchanger networks. Recently technology has been further developed into ?Pinch Technology”?. At the end of process development comes the final detailed optimization. The expensive and time consuming sequential way of working used in the past is being gradually replaced today with equation-oriented simulation and optimization tools such as the OPTISIM program. Expert systems, in principal, offer the chance of supporting the chemical engineer during the initial design of complete and complex processes. However, the experience with such systems to date has shown that a practical solution lies a long way into the future.     

Rechnergestützte exergetische Optimierung verfahrenstechnischer Prozesse

Computer-aided exergy optimization of chemical engineering processes. Methods of exergy evaluation as the basis of energy and material analysis of chemical processes have been used for some years to evaluate these processes from the view point of the First and Second Law of Thermodynamics and with regard to their influence on the environment. This paper introduces a tool for computer-aided exergy analysis and optimization of complex process plants. This tool is based on a flowsheeting program that is extended to calculate the exergy of material, heat, and work flows. The optimization problem of process plants is solved in a two level approach by parameter optimization and structural optimization. The parameter optimization is realized automatically by the extended flowsheeting program. The structural optimization is based on heuristic rules and experiences of the process engineer.     

Exergetic and engineering analyses of sulphuric acid decomposition process

The purpose of this study was to evaluate the exergetic efficiency of the sulphuric acid decomposition process, which occurs in hydrogen producing thermochemical cycles and chemical energy storage systems. It is a process in which sulphuric acid is decomposed to a gaseous mixture consisting of water, sulphur dioxide and oxygen, using high temperature thermal energy, oxygen as a vector and mostly adiabatic equipment. Parts of the basic process with excessive exergy losses have been identified and a modified flow sheet has been developed and analyzed from thermodynamic and engineering points of view. Thermodynamic analysis of the modified flow sheet indicates that the overall exergetic efficiency of the decomposition process is 79.86%, which represents an improvement of 14.17% over the basic process. Engineering analysis of a plant producing 10⁶ mol of SO₂ per hour shows that the typical levelized cost of chemical exergy production was $ 2.25/GJ exergy from the basic process and $ 1.79/GJ exergy from the modified process.     

Process intensification aspects for steam methane reforming: An overview

Steam methane reforming (SMR) is the most widely used process in industry for the production of hydrogen, which is considered as the future generation energy carrier. Having been perceived as an important source of H₂, there are abundant incentives for design and development of SMR processes mainly through the consideration of process intensification and multiscale modeling; two areas which are considered as the main focus of the future generation chemical engineering to meet the global energy challenges. This article presents a comprehensive overview of the process integration aspects for SMR, especially the potential for multiscale modeling in this area. The intensification for SMR is achieved by coupling with adsorption and membrane separation technologies, etc., and using the concept of multifunctional reactors and catalysts to overcome the mass transfer, heat transfer, and thermodynamic limitations. In this article, the focus of existing and future research on these emerging areas has been drawn. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

酯交换法制备碳酸二甲酯过程模拟与系统火用分析

针对酯交换制备过程中甲醇?碳酸二甲酯共沸体系难分离的问题,分别选择变压精馏、碳酸乙烯酯(EC)萃取精馏与乙二醇(EG)萃取精馏3种分离过程进行模拟与能量集成,对比了3种工艺流程的分离能耗,采用有效能(?)分析方法分析了能耗最低的变压分离过程的有效能(?)损失. 结果表明,3种工艺流程的能耗EG萃取精馏>EC萃取精馏>变压精馏,碳酸二甲酯生产过程中内部循环物流能量是输入总能量的1.55倍,变压共沸分离过程的?损失为7.9%。     

Exergetic criteria in process optimisation and process synthesis: Opportunities and limitations

The exergy concept is a well established way to express the quality of any kind of process stream, be it energy or matter. Thus detailed exergy analysis of chemical processes can in general be performed and several such applications have been reported in the literature. However, systematic methods for exergetic process optimisation only exist for the comparably less complex area of power systems. For chemical processes a solid optimisation approach based on exergy analysis has yet to be derived. This paper presents a thorough investigation of opportunities and limitations of the exergy concept in both process optimisation and process synthesis. The two tasks are treated separately since their specific requirements and solution strategies are different. As a result of the presented evaluation, concepts for the efficient use of exergetic criteria are proposed.     

Perspektiven für die Forschung im Chemieingenieurwesen: Die französische Politik

The future of chemical engineering research – the French policy . Future prospects of chemical engineering research are set forth, as they result from discussions organized by the French government. In the first part, the situation in French Research Institutes is briefly described: programmes, structure, financial support and co-operation with industry. In the second part, the role of Chemical Engineering in solving problems in industrial societies is discussed. Prominence is given to cases of successful industrial scaling-up of laboratory processes, with emphasis given to the following: systems approach, modelling methods for fast and safe design, rapid adaptation of process industries to changes in economic conditions, application of chemical engineering concepts to new areas of biology, nutritional and soil sciences, electrochemical, solar and nuclear engineering etc. Problems which remain unsolved and future research topics are presented: heat and mass transfer in multiphase media, exergetic process analysis and causes of exergy losses in unit processes, new separation processes and reactor types, processes based on materials which can be regenerated, and automation of chemical processes.     

2003年石油化工绿色化学与化学工程的进展

2003年国际上更加重视绿色化学与技术的研究开发,绿色化学被认为是应用于解决全球环保问题的多学科交叉的科学与工程.中石化己内酰胺生产中三套绿色新工艺从基础研究到工业化,证明我国科技人员具有开发崭新工艺以推动跨越式技术进步的能力.美国实现了从玉米工业化生产1,3-丙二醇和聚乳酸热塑体,表明从可再生资源生产大宗有机化工产品不仅技术可行,而且经济合理,具有里程碑意义.最后回顾了2003年在离子液体、超临界反应工程和化工过程强化等领域的进展,这些领域都是可能导致绿色石化新工艺的科技前沿.     

典型过程强化技术在纳米材料制备中的应用进展

纳米材料被誉为21世纪的新材料,广泛应用于化工、电子、国防、陶瓷等领域.传统的纳米材料制备方法面临粒径控制较困难、批次间重复性差,存在放大效应等不足.过程强化技术是化学工程学科的研究前沿和热点方向之一,旨在通过在生产过程中采用新工艺、新设备等手段,实现缩减操作单元、减小设备体积、提高生产能力及能量利用效率的目的,是实现...     

On maximum power of reverse osmosis separation processes

This paper considers the application of finite time thermodynamics (FTT) to reverse osmosis (RO) processes. A new thermodynamically ideal model of the endoreversible RO process is proposed and combined with basic transport equations for the irreversible mass transfer through the membrane. This approach is then applied to a simplified case of RO desalting of a concentrated sodium chloride solution. The results emphasize the trade-off between the permeate flow rate and the recovery rate. It also shows the existence of a maximum value for the power of separation which corresponds to the maximum conversion rate of mechanical exergy into chemical exergy. Finally the environmental and technical significances of the criteria such as power of separation are discussed on an example of the RO process.     

体现“三海一核”特色的化学工程与工艺专业课程群建设

选择化工传递过程、化工热力学、分离工程、化学反应工程、化工工艺学五门课程构建化学工程与工艺专业核心课程群,并对核心课程内容进行整合,教学内容体现“三海一核”特色。在此基础上,通过加大选修课比重,我们在实验教学、毕业设计、毕业实习等环节中,强化工程意识,提高学生创新能力。     

Exergy analysis of thermal processes in the building materials industry

A method is proposed to calculate the chemical exergy with allowance for the chemical composition and the ambient temperature. The exergy analysis of cement clinker burning is performed. It is found that the maximal energy saving for a rotary cement kiln can be achieved by decreasing the sludge humidity and optimizing the fuel combustion and the clinker cooler operation. The analysis of thermal processes in terms of exergy characteristics is demonstrated to be more efficient than that in terms of thermal parameters, since the optimization and intensification of industrial kilns requires not only heat loss reduction but also more efficient use of heat.     

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。     

Exergy analysis of desalination by solar-powered membrane distillation units

There has been an increasing interest in using exergy as a potential tool for analysis and performance evaluation of desalination processes where the optimal use of energy is considered an important issue. Unlike energy, exergy is consumed or destroyed due to irreversibilies in any real process and thus provides deeper insight into process analysis. Exergy analysis method was employed to evaluate the exergy efficiency of the “compact” and “large” solardriven MD desalination units. The exergy efficiency of the compact and large units with reference to the exergy collected by the solar collector was about 0.3% and 0.5% but was 0.01% and 0.05%, respectively, when referenced to the exergy of solar irradiance. The exergy efficiency of the flat plate solar collectors in both units varied diurnally and the maxima was 6.5% ad 3% for the compact and large units, respectively. The highest exergy destruction was found to occur within the membrane distillation module.     

Stoff- und Energiewandlungen bei verfahrenstechnischen Prozessen

Mass and Energy Conversion in Processes of Chemical Engineering . Being the practice of chemical engineering, chemical industry is among the industrial branches with a high energy consumption. This is scientifically based on the unity of mass and energy conversion. Although theoretically well-known these interconnections have only little influence on engineering investigations. That's why incomplete and untrue evaluations of the energetic conditions of chemical processes can occur. After a brief historical survey, a classification of the different kinds of energy for chemical processes will be proposed as a help in solving this problem. This classification facilitates a deeper understanding of the energetics of chemical processes. To increase these investigations the term cumulative exergy expenses can be used for the evaluation of chemical processes. This evaluation considers both the conversion of energy and the conversion of mass. These connections are discussed by one example. If these research purposes are generalised for strategic development, they will lead to a new generation of chemical and energetical plants.     

旋流分离过程强化新技术

旋流器作为一种典型的非热物理分离设备,具有结构简单、分离效率高、处理能力大、运行和维护成本低等技术优势,在石油、化工、环保、采矿等众多领域中获得了广泛的应用。随着旋流分离过程强化技术的发展,旋流分离精度也从毫米级发展到微米级、纳米级甚至是离子分子级。本文围绕旋流分离过程强化的科学原理和工程应用,介绍了旋流分离过程强化新技术方面的研究进展。系统总结了由一维点到二维面,再到三维体的旋流场连续相流场测试方法,介绍了基于微流控技术和高速摄像技术的适用于检测快速螺旋迁移颗粒运动速度的同步高速运动分析（S-HSMA）系统,以及基于该系统发现的旋流场中颗粒高速自转等新现象。旋流自转已经实现从现象发现到工程应用的突破,本文还介绍了基于颗粒高速自转的旋流吸收、旋流萃取、旋流脱附等分离强化过程新原理以及气泡强化废水旋流除油、颗粒排序强化微细颗粒旋流分离、多孔颗粒旋流自转除油等旋流分离过程强化新方法及设备。     

一种新型反应设备——旋转填料床技术及其应用

旋转填料床技术是一种突破性的过程强化新技术，在化工、能源、环保、材料、生物化工等工业领域中有广阔的商业化应用前景，笔者概要介绍了该新技术的特点，国内外研究开发和应用。     

绿色过程工程

论述了绿色过程工程科学的产生背景与科学内涵,并以研究实例进行解析,讨论了在环境-经济综合评价体系下资源利用-物质转化过程的研究方法、目标、内容和前景. 指出绿色过程工程中的化学-物理-生物-计算信息与环境学科的交叉整合、物质与能量流程优化集成、反应-分离过程强化与序列综合、操作控制优化与多尺度工程研究理论,并归纳为过程工业绿色过程的工程放大优化设计,为过程工业的绿色化升级更新和21世纪生态工业新模式提供科学与工程依据