传质分离过程-课件.ppt

1、化工分离过程化工分离过程Chemical Separation Processesclass hours : 48credits: 3.0中文教材中文教材刘家祺 主编，李韡、吴洪、姜忠义 参编. 化学工业出版社，2005年12月.曾用教材曾用教材20021995TextbookJ.D.Seader, E.J.Henley. Separation Process PrinciplesJ. D. Seader199820062002J. D. Seader20041. Development of new mathematical methods for solving large sets of

2、 nonlinear equations to obtain multiple solutions. 2. Mathematical studies of computer- aided process synthesis and design. References-Books Phillip C. Wankat Separation Process Engineering (2006) J.L.Humphrey, G.E. Keller Separation Process Technology (1997) Kirk-othmer Encyclopedia of Chemical Tec

3、hnology. 4th ed, New York, Wiley. Cary Judson King Separation processes (1980) Ernest J. Henley, J. D. Seader Equilibrium-stage separation operations in chemical engineering (1981)References-JournalsAIChE Journal, ACSChemical Engineering Science, Elsevier ScienceIndustrial & Engineering Chemistry Re

4、search, ACSChemical EngineeringTechnology, WileySeparation and Purification Technology，Elsevier ScienceReferences-JournalsJournal of membrane Science,Elsevier ScienceFundamentals of various separation processes and the tools necessary for selecting the most suitable separation sequence for a require

5、d task. Equilibrium-based processes such as distillation, extraction, absorption and stripping, adsorption and crystallization as well as rate-governed processes such as membrane separation.Discussion of comparative energy requirements, economics, advantage and disadvantages of proposed separation t

6、asks. Course DescriptionCourse objectivevGet an overview on separation processes relevant to the chemical and process industryvLearn some of these separation processes in varying degrees of detail: Principles Applications CalculationsChemical Separation PrinciplesContents Chapter 1 SeparationProcess

7、es Chapter 2 Thermodynamics of Separation Operations Chapter 3 Mass Transfer and Diffusion Chapter 4 Singer Equilibrium Stages and Flash Calculations Chapter 5 Cascades Chapter 6 Absorption and Stripping of Dilute Mixtures Chapter 7 Distillation of Binary Mixtures Chapter 8 Liquid-liquid Extraction

8、with Ternary Systems Chapter 9 Approximate Methods for Multicomponent, Multistage Separations Chapter 10 Equilibrium-based Methods for Multicomponent Absorption, Stripping, Distillation, and Extration Chapter 11 Enhanced pproximate Methods for Multicomponent, Multistage Separations Chapter 12 Rate-b

9、ased Models for Distillation Chapter 13 Batch Distillation Chapter 14 Membrane Separations Chapter 15 Adsorption, Ion Exchange, and ChromatographyContents (contd)传质分离过程传质分离过程第第1 1章章 绪论绪论第第2 2章章 传质分离过程的热力学基础传质分离过程的热力学基础第第3 3章章 气液传质分离过程气液传质分离过程第4章 液液传质分离过程第第5 5章章 传质分离过程的严格模拟计算传质分离过程的严格模拟计算第6章 气固、液固传质分

10、离过程第第7 7章章 分离过程的节能优化与集成分离过程的节能优化与集成教学目标教学目标-Objective 利用已学的利用已学的物理化学、化工原理、物理化学、化工原理、化工热力学、传递过程化工热力学、传递过程等课程中有等课程中有关相平衡热力学和动力学机理，传关相平衡热力学和动力学机理，传热、传质和动量传递理论来研究化热、传质和动量传递理论来研究化工生产实际中复杂物系的分离和提工生产实际中复杂物系的分离和提纯技术。纯技术。 着重基本概论的理解，为分离过着重基本概论的理解，为分离过程的选择、特性分析和计算奠定基程的选择、特性分析和计算奠定基础。从分离过程的础。从分离过程的共性共性出发，讨论出发，讨

11、论各种分离方法的特征。强调将工程各种分离方法的特征。强调将工程和工艺相结合的观点及设计和分析和工艺相结合的观点及设计和分析能力的训练；强调理论联系实际，能力的训练；强调理论联系实际，提高解决问题的能力。提高解决问题的能力。教学要求教学要求-Requirements掌握各种常用分离过程的基掌握各种常用分离过程的基本原理，操作特点，简捷和本原理，操作特点，简捷和严格计算方法，强化改进分严格计算方法，强化改进分离过程操作的途径，并了解离过程操作的途径，并了解一些新型分离技术。一些新型分离技术。 讲授内容讲授内容第第1章章 绪论绪论第第2章章 传质分离过程的热力学基础传质分离过程的热力学基础 两组分平

12、衡计算，已知一相中的浓度，求另一相的浓度。 泡点温度、露点温度、闪蒸计算。第第3章章 气液传质分离过程气液传质分离过程 过程分析：e.g.精馏中温度分布、组成分布、流量分布。 简捷计算（short-cut）：确定关键组分、最少理论板、最小回流比、实际板数、实际回流比。 萃取精馏和共沸精馏特殊精馏。 气体吸收：过程分析；吸收的简捷计算。讲授内容讲授内容第第5章章 传质分离过程的严格模拟计算传质分离过程的严格模拟计算 建立通用模型，求解三对角矩阵（泡点法，流率加合法）。第第7章章 分离过程的节能优化与集成分离过程的节能优化与集成 分离过程最小功和热力学效率，精馏的节能技术，分离流程优化和集成第一章

13、第一章 绪绪 论论第一章第一章 绪绪 论论Chapter 1 Introduction1.1 传质分离过程的分类传质分离过程的分类 Classes of Separation Operation1.2 分离过程的研究和技术开发分离过程的研究和技术开发 Study on Separation Process and Development 主要内容及要求：主要内容及要求： 了解分离操作在化工生产中的重要性，了解分离操作在化工生产中的重要性，分离过程的分类。分离过程的分类。 了解化工分离过程的研发现状和发展了解化工分离过程的研发现状和发展趋势。趋势。What is Separation?Basic

14、 Description of OperationsOperations are classified as key operations and auxiliary operations Key Operation: involves reaction or separationsExamples: distillation, leaching, reactor Auxiliary Operation: involves no change in chemical compositionExamples: pumps, heaters, compressorsWhat is Separati

15、on?纯组分变成混合物，是熵增自发过程，反之，纯组分变成混合物，是熵增自发过程，反之，混合物变成纯净物则需作功。混合物变成纯净物则需作功。Mixing is inherent in nature: The increase in entropy associated with the randomness of a mixture lowers the Gibbs free energy.To “unmix” a solution we must overcome the entropic driving force to mix.What is Separation?借助一定的分离剂，实现混

16、合物中的组分分级借助一定的分离剂，实现混合物中的组分分级（Fractionalization）、浓缩）、浓缩（Concentration）、富集（）、富集（Enrichment）、）、纯化（纯化（Purification）、精制（）、精制（Refining）与）与隔离（隔离（Isolation）等的过程称为分离过程。）等的过程称为分离过程。Why Separate？In Human BodySeparation processes: Our life depends on theseKidney: the perfect ultrafilter静脉静脉动脉动脉肾小球肾小球输尿管输尿管Separ

17、ation of oxygen from air and of CO2 from blood in the lungsSelective removal of water and waste products of metabolism from blood in the kidneysSelective absorption of nutrients in the intestines. In IndustryWhy Separate？ 工程应用需要纯物质（如半导体材料）；工程应用需要纯物质（如半导体材料）；Need for pure material in engineering appl

18、ication (semiconductors) 原料提纯；原料提纯； Preparation of raw materials into their components 材料加工需要纯物质；材料加工需要纯物质；Need for pure material for materials processing 有毒有害物质或非活性物质的去除（如药物）；有毒有害物质或非活性物质的去除（如药物）；Need to remove toxins or inactive components from solution (drugs) 测试或检测用超纯标准品；测试或检测用超纯标准品； Need for ul

19、trapure samples for testing 混合物组成检测（如混合物组成检测（如DNA检测）；检测）；Need for analysis of the components of the mixture (DNA testing) Separation ProcessThe separation process may be defined as those operations which transform a mixture of substances into two or more products which differ from one another in com

20、position.Analytical Separations small scale quantitative analysisPreparative Separations small scale materials for R&DIndustrial Separations large scale economicalExample:ChromatographyExample:CentrifugationExample:DistillationDistillation ColumnExample: Refinery of crude oilRefinery for converting

21、crude oil into a variety of marketable products.Example: Production of p-xylene16. 1orthopara02. 1metaparaDistillationCrystallizationExample: Production of p-xyleneThere are four different classes of separation process involved in the production1. Vapor-Liquid Separation (Hydrogen recovery); 2. Dist

22、illation (Debutanizer,Regenerator,Splitter, Recover; 3. Extraction; 4. Crystallization先修课程先修课程物理化学、化工热力学、物理化学、化工热力学、化工原理、传递过程化工原理、传递过程化工原理（化工原理（unit operations），涉及热），涉及热力学（物理化学）、三传力学（物理化学）、三传两组分精馏两组分精馏多组分非理想物系如何分离？多组分非理想物系如何分离？单元操作与分离过程单元操作与分离过程Unit Operation vs. Separation Process单元操作单元操作 尽管人们在尽管人们

23、在1893年对单元操作就有所认年对单元操作就有所认识，但真正的提出是在识，但真正的提出是在1915年。年。 Arthur D Little（1863-1935）在给）在给MIT校校长的信中写到：长的信中写到： 任何化学过程，不管规模大小，都可以任何化学过程，不管规模大小，都可以认为是由一系列可以被称为认为是由一系列可以被称为“单元操作单元操作”的过程组成的。的过程组成的。 Arthur D Little coined the term “unit operations” in 1915 to distinguish chemical engineering from all other pro

24、fessions and also to give chemical engineering programs a common focus, and headed up AIChEs Committee on Chem. Eng. Education which emphasized the unit operation concept along with accreditation to standardize courses in chemical engineering programs. 分离过程分离过程“分离过程分离过程”形成一个独立领域的两形成一个独立领域的两个重大事件是：个重

25、大事件是：1984年年Norman Lee组组织召开的分离技术工程基础会议和织召开的分离技术工程基础会议和1987年美国国家研究院的研究报告提年美国国家研究院的研究报告提出：出：“分离和纯化：迫切需要和现实分离和纯化：迫切需要和现实机会机会”，对分离过程的定义、分类、，对分离过程的定义、分类、研究目标和任务等进行了更为明确的研究目标和任务等进行了更为明确的描述。描述。 1991年，美国化学工程师协会（年，美国化学工程师协会（AIChE）把国家项目委员会（把国家项目委员会（National Program Committee）中的第二组由）中的第二组由“单元操作组单元操作组”更名为更名为“分离组

26、分离组”，标志着单元操作向，标志着单元操作向分离过程的过渡。分离过程的过渡。 对于大学教育来说，分离过程对于大学教育来说，分离过程是为数不多的带有纯粹工程特点是为数不多的带有纯粹工程特点的课程。同反应器和过程设计一的课程。同反应器和过程设计一样，分离过程是一门帮助化学工样，分离过程是一门帮助化学工程与工艺专业的学生建立起工程程与工艺专业的学生建立起工程概念的很好的课程。概念的很好的课程。Separation processes The legacyExamples for early separation techniquesvSalt by evaporating sea water 晒盐晒

27、盐vMetals extracted from ores 冶金冶金vPerfumes extracted from plants 香料提取香料提取vVarious drinks, medicines extracted from plants 天然饮料和药物生产天然饮料和药物生产vLiquors distilled from plants 果酒生产果酒生产Separations in Modern Chemical Industry Crucial in Chemical Engineering Most equipments - purifying products Chemical Pla

28、nts50 - 90 % capital investment化工厂中分离设备投资约占化工厂中分离设备投资约占总投资的总投资的50509090 ！Basis of Separation Size 尺寸尺寸 Shape 形状形状 Charge 荷电性荷电性 Polarity 极性极性 Solubility 溶解性溶解性 Volatility 挥发性挥发性 Mobility 运动性运动性Distillation Separation depends on distribution of components between gas and liquid phase All components d

29、istribute at equilibrium Gas phase - application of heat Liquid phase - removal of heatAbsorption/Stripping Gas mixture contacted with liquid Absorption - dissolving components of gas into liquid Stripping - mass transfer goes from liquid to gasAdsoprtionA surface phenomenonDepends on selective bind

30、ing of a solute to a surfaceUsed for:Gas separation Fractionation of industrial chemicalWaste treatmentDe-hydration or de-humidification of gasesWater purificationFractionation and recovery of biopolymersChromatographyUtilizes differential migration velocities of components within a separation devic

31、eA novel separation processUsed for:Pharmaceutical and fine chemical fractionationsBioseparationEnvironmental separationsAnalysis of chemicalsDiagnosticsSample analysis for process controlLiquid Extraction Liquid solution contacted with another insoluble liquid. Constituents distribute differently b

32、etween the two liquid phasesSupercritical fluid extractionA novel separation processUsed for:Separation and purification of oils, flavours and medicinal componentsRemoval of greasy materialConversion of azeotropic water-ethanol mixture to an anhydrous ethanolFractionation and purification of polymer

33、sMembrane separation processes Novel separation processes Utilizes selective barrier Used for: Bioseparation Medical separations Clarification Recovery of cells from bioreactors Waste treatment Gas separationSeparation processesLiquid-liquid extraction 液液萃取液液萃取Adsorption 吸附吸附Filtration 过滤过滤Solid-liq

34、uid extraction (leaching) 固液萃取固液萃取Elution chromatography 洗脱色谱洗脱色谱Membrane separation processes 膜分离膜分离Distillation 精馏精馏Affinity separation processes 亲和分离亲和分离Drying and evaporation 干燥和蒸发干燥和蒸发Freeze-drying 冷冻干燥冷冻干燥Precipitation 沉淀沉淀Crystallization 结晶结晶Electrophoresis 电泳电泳Centrifugation 离心分离离心分离Mechanic

35、al sieving 机械筛分机械筛分Technological and use maturities of separation processes分离过程的分类分离过程的分类级数级数：相态相态：单级、多级单级、多级固固固、固固、固液、固液、固气、气气、气液、液、液液液、气液、气气气操作方式操作方式：连续、间歇、半连续连续、间歇、半连续规模规模：分析型分离、制备型分离、工业分离分析型分离、制备型分离、工业分离分离方法按机理的分类分离方法按机理的分类phase creationMechanism of Separationphase additionbarriersolid agentforc

36、e fieldMost commonGaining popularityOften in labsPhase CreationPhase AdditionPhase 1Phase 2FeedMSAPhaseCreationPhase 1Phase 2FeedSeparation by phase creation or addition通过相的创造和加入来进行分离通过相的创造和加入来进行分离Phase 1Phase 2FeedBarrierSeparation by barrier通过障碍物分离通过障碍物分离分离过程的分类分离过程的分类有无传质发生：有无传质发生：机械分离、传质分离机械分离、传

37、质分离处理两相以上的混合物处理两相以上的混合物如过滤、沉降、离心分离等。如过滤、沉降、离心分离等。处理均相混合物处理均相混合物Classificatin of Separation OperationMechanical Separation processes(feed consisting of more than one phase of matter and simply serves to separation the phases from one another) Heterogeneous MixtureMass transfer Separation processes(Th

38、ere is only one phase in feed) Homogeneous MixtureSettlingFiltrationCentrifugationVortrapSEPARATIONPROCESSESMechanism of Separations UNMIXING is not a spontaneous process in natureA process requiring no external driving forceReduces randomness and thus the entropy of the system Separations involve n

39、onspontaneous processes Usually the mixture to separate is a homogeneous, single phase: If not, then often one will phase separate first gravity centrifugation filtration.1.1 Classifications of Mass Transfer Separation Processes按物理化学原理的不同，传质分离可分为：按物理化学原理的不同，传质分离可分为：传质分离过程的分类传质分离过程的分类平衡分离过程：平衡分离过程：速率

40、分离过程速率分离过程：借助分离剂使均相混合物系统变成两相系统，借助分离剂使均相混合物系统变成两相系统，再利用混合物中各组分在处于相平衡的两相中再利用混合物中各组分在处于相平衡的两相中的不等同分配而实现分离。的不等同分配而实现分离。在某种推动力（浓度差、压力差、温度差、电在某种推动力（浓度差、压力差、温度差、电位差等）的作用下，利用各组分扩散速率的差位差等）的作用下，利用各组分扩散速率的差异实现分离。异实现分离。如精馏、吸收、萃取、结晶、吸附等。如精馏、吸收、萃取、结晶、吸附等。如微滤、超滤、反渗透、电渗析等。如微滤、超滤、反渗透、电渗析等。Mass transfer Separation pr

41、ocesses Equilibration Separation ProcessesIf the mixture to be separated is a homogeneous single-phase solution, a second phase must generally be developed before separation, and the subsequent separation of chemical species can be achieved by employing difference in partition for different species

42、between two phases. This second phase can be created by an energy separation agent (ESA) or by a mass separation agent (MSA). 平衡分离过程平衡分离过程混合物混合物（气、液、固）（气、液、固）分分 离离 过过 程程产品产品1产品产品2产品产品n能量分离剂能量分离剂 ESA质量分离剂质量分离剂 MSA极限程度极限程度- 热力学热力学分离速率分离速率- 动力学动力学Limits:Extent = Thermodyanmics Rate = TransportBackgroun

43、d Material for SeparationsThe fundamentals that we will apply to study separations in this course involve: Materials and energy balances: conservation of energy and matter Thermodynamics: phase equilibrium and solution thermodynamics Transport phenomena Chemical reaction kinetics: rate of conversion

44、 of one species to anotherFor the most part our analysis of various separations processes will focus on using phase equilibrium and materials and energy balances.An MSA may be partially immiscible with one or more of the species in the mixture. In this case, the MSA is frequently the constituent of

45、highest concentration in the second phase. Application of an ESA involves heat transfer and/or work transfer to or from the mixture to be separated. Alternatively, a second phase may be created by reducing the pressure.ESA & MSA闪蒸闪蒸 （Flash）部分冷凝部分冷凝 （Partial Condensation）精馏精馏 （Distillation）特殊精馏特殊精馏 （

46、Enhanced Distillation） 萃取精馏萃取精馏 （Extractive Distillation） 共沸精馏共沸精馏 （Azeotropic Distillation）萃取萃取 （Extraction）、超临界流体萃取）、超临界流体萃取 （SCFE）吸收吸收 （Absorption）、解吸）、解吸 （Desorption）结晶结晶 （Crystallization）吸附吸附 （Adsorption）、离子交换）、离子交换 （Ion Exchange）膜蒸馏、膜萃取、双水相萃取、反胶团萃取膜蒸馏、膜萃取、双水相萃取、反胶团萃取 、变压吸附、变压吸附Examples of Equi

47、libration Separation Processes The rate-governed separation processes is usually diffusion under the influence of a concentration field, temperature difference, electrical field, etc. A separation of species can be achieved based on difference in transport rates. Separation processes produce product

48、 streams which are the same phase of feed streams and which are miscible with one another. Rate-governed Separation Processes速率分离过程速率分离过程在某种推动力（浓度差、压力差、温度差、电位差等）在某种推动力（浓度差、压力差、温度差、电位差等）的作用下，或在选择性透过膜的配合下，利用各组分的作用下，或在选择性透过膜的配合下，利用各组分扩散速率的差异实现分离。扩散速率的差异实现分离。 膜分离过程示意膜分离过程示意 Membrane Separation Processes

49、The use of microporous and nonporous membranes as semipermeable barriers for application to difficult and highly selective separation is rapidly gaining adherents in industrial separation processes. For the microporous membranes, separation is effected by differing rates of diffusion through the por

50、es; while for nonporous membranes, separation occur because of difference in both solubility in the membrane and the rate of diffusion through the membrane.Membrane Separation MechnismsSolution-diffusionRestricted diffusionDiffusion through poresBulk flow through poresDiffusion through a membranemem