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1、化工热力学课件章第1页,本讲稿共34页 热力热力 学学(thermodynamics)作为一门科学诞生于作为一门科学诞生于19世纪,最初用世纪,最初用于研究和描述蒸汽机于研究和描述蒸汽机(steam engine)的操作以及蒸汽机工作的极限,的操作以及蒸汽机工作的极限,后来上升到热机后来上升到热机(heat engine)的研究和应用。的研究和应用。“热力学热力学”名称的本身名称的本身就意味着就意味着“来自热的能量来自热的能量”,因为,因为thermo代表热,代表热,dynamics代表动代表动力。热力学在研究热机工作的基本原理过程中,总结、归纳出了力。热力学在研究热机工作的基本原理过程中,总
2、结、归纳出了著名的热力学第一定律和热力学第二定律。著名的热力学第一定律和热力学第二定律。第2页,本讲稿共34页 热力学第一定律和热力学第二定律没有任何数学意义上的证明,它热力学第一定律和热力学第二定律没有任何数学意义上的证明,它是自然界基本规律的总结,迄今为止,没有任何人对这二个定律提出异是自然界基本规律的总结,迄今为止,没有任何人对这二个定律提出异议(除了一些科学狂人),自然界发生的过程或出现的现象也都遵循这议(除了一些科学狂人),自然界发生的过程或出现的现象也都遵循这二个定律。二个定律。第3页,本讲稿共34页 热力学第一和第二定律奠定了热力学科学的理论基础。从热力学第热力学第一和第二定律奠
3、定了热力学科学的理论基础。从热力学第一和第二定律出发,通过一系列数学推导,建立了一整套的热力学公式,一和第二定律出发,通过一系列数学推导,建立了一整套的热力学公式,形成了完整的热力学理论体系。这就是我们今天所认识的热力学。形成了完整的热力学理论体系。这就是我们今天所认识的热力学。伴随热力学科学的形成和发展,产生了一批著名的数学家伴随热力学科学的形成和发展,产生了一批著名的数学家和化学家,其中,贡献最大的是美国数学家和化学家,其中,贡献最大的是美国数学家Josiah Willard Gibbs。下面是下面是Josiah Willard Gibbs的介绍。的介绍。第4页,本讲稿共34页Josiah
4、 Willard Gibbs(1839-1903)第5页,本讲稿共34页 Josiah Willard Gibbs(1839-1903)has been reckoned as one of the greatest American scientists of the 19th century.He provided a sound thermodynamic foundation to much of Physical Chemistry.“Gibbs Phase Rule”is well known to all in the field today.Yale educated,he w
5、as awarded the first Doctor of Engineering in the U.S.,and was appointed Professor of Mathematical Physics at Yale in 1871.In 1873 he published his first major works,Graphical Methods in the Thermodynamics of Fluids.In 1876 came his most famous paper:On the Equilibrium of Heterogeneous Substances.第6
6、页,本讲稿共34页John M.Prausnitz第7页,本讲稿共34页 The research purpose of Prausnitz is to obtain,interpret and correlate thermodynamic properties of a variety of mixtures as required for process and product design in the chemical and related industries,including biotechnology.Toward that end,we obtain experiment
7、al data,perform Monte-Carlo molecular simulations and develop molecular-thermodynamic models based on the statistical mechanics of fluids and solids.Attention is given to crude oils,natural gas,polymers and protein solutions.While these research studies contribute to our fundamental understanding of
8、 condensed matter,their primary application is for economic,industrial-scale chemical engineering design.目前目前Prof Prausnitz 的研究领域和研究方法的研究领域和研究方法第8页,本讲稿共34页Kenneth S.Pitzer(1914-1997)另一个近代热力学著名学者另一个近代热力学著名学者第9页,本讲稿共34页 Kenneth S.Pitzer was born in Pomona,California,in 1914.He received his B.S.in 1935
9、 from Caltech and his Ph.D.in chemistry from UC Berkeley in 1937.He was immediately appointed to the faculty of the Department of Chemistry at Berkeley,where he spent most of his distinguished career.Professor Pitzer took leave to serve in Washington,D.C.,during World War II and again from 1949 to 1
10、951,when he was Director of Research for the Atomic Energy Commission.Upon returning to Berkeley,he was appointed Dean of the College of Chemistry,a position that he held until 1960.He subsequently became President first of Rice University(1961-1968)and then of Stanford University(1969-1971).In 1971
11、,he returned to Berkeley,becoming Professor Emeritus in 1984.第10页,本讲稿共34页 Professor Pitzer was the founder of modern theoretical chemistry at Berkeley.He not only used quantum and statistical mechanics to explain the thermodynamic and conformational properties of molecules,but he also pioneered quan
12、tum scattering theory for describing chemical reactions at the most fundamental level.He also made contributions to relativistic effects in chemical bonding and the theory of fluids and electrolyte solutions.第11页,本讲稿共34页化工热力学面临的问题化工热力学面临的问题 化工热力学面临的最大问题是:化工热力学面临的最大问题是:理论研究多理论研究多,实际应用少实际应用少。美国美国 Univ
13、ersity of California,Berkeley 的的Prausnitz 教授是近教授是近代化工热力学领域最著名的一位学者,下面引用他在论文代化工热力学领域最著名的一位学者,下面引用他在论文“Thermodynamics and Other Chemical Engineering Sciences:Old Models for New Chemical Products and Processes”(Fluid Phase Equilibria 158-160,1999)中的一段话)中的一段话,说明目前化工热力学存在,说明目前化工热力学存在的问题。的问题。第12页,本讲稿共34页
14、“Chemical engineering thermodynamics has many talented researchers working on a wide variety of projects.But all too often when I read erudite articles in the literature,the author seems to be saying:“I have an answer.But I dont know the question.”“Do the best work in Thermodynamics that you possibl
15、y can and enjoy it thoroughly.But dont lose sight of the goal.Thermodynamics comes second.First comes Chemical Engineering.”第13页,本讲稿共34页 热力学问题的分类热力学问题的分类1.For a given process with prescribed(or idealized)internal constraints and boundary conditions,how do the properties of the system vary?第14页,本讲稿共3
16、4页2.To cause given changes in system properties,what external interactions must be imposed?(This is the inverse of Type 1.)3.Of the many alternative processes to effect a given change in a system,what are the efficiencies of each with respect to the resources at our disposal?第15页,本讲稿共34页How to solve
17、 these problems?Type 1 和和 Type 2 二类问题的解决需要应用热力学第一定律二类问题的解决需要应用热力学第一定律(the First Law),如在物理化学课程中学习的封闭体系第一定律,如在物理化学课程中学习的封闭体系第一定律在化工热力学课程中学习的稳流体系第一定律在化工热力学课程中学习的稳流体系第一定律 热力学第一定律可以广义地写成如下形式:热力学第一定律可以广义地写成如下形式:Internal changes=interactions occurring at boundaries第16页,本讲稿共34页 第一定律中体系的能量变化可以同体系其它的一些性质,第一定律
18、中体系的能量变化可以同体系其它的一些性质,如如 T、P、V 等相关联,因此,可以通过改变体系的等相关联,因此,可以通过改变体系的T、P、V 等性质,实现体系的状态变化。等性质,实现体系的状态变化。Type 3 问题的解决,需要热力学第二定律(问题的解决,需要热力学第二定律(the Second Law)。)。这时,引入一个被称为可逆过程(这时,引入一个被称为可逆过程(reversible process)的理想化过)的理想化过程,作为比较实际过程效率的标准。程,作为比较实际过程效率的标准。第17页,本讲稿共34页 任何一个热力学问题,原则上都可以用下面的三步法解决。任何一个热力学问题,原则上都
19、可以用下面的三步法解决。1.Problem definition and modeling The real-world situation must be modeled by specifying the internal constrains and boundary conditions.Idealizations must frequently be introduced to make the problem tractable.Is a boundary permeable,semipermeable,or impermeable?Are the contents of the
20、system well-mixed and homogeneous?第18页,本讲稿共34页Is heat transfer fast or slow relative to the time span of interest?Which chemical reactions are known to occur under the conditions of interest?2.Application of thermodynamic laws and mathematical reasoning For example,for a simple,non-reacting system o
21、f fixed moles undergoing a process in which the temperature and pressure are observed to change from T1,P1 to T2,P2,we might wish to know the necessary heat and work interaction.第19页,本讲稿共34页Applying the First LawMathematical reasoningWhere第20页,本讲稿共34页3.Evaluation of property data For example,we must
22、 evaluate the following property functions to calculate(nU),第21页,本讲稿共34页高等化工热力学高等化工热力学的主要内容的主要内容第22页,本讲稿共34页主要任务:主要任务:深入理解热力学的基本原理和理论公式,掌握用热力学解决深入理解热力学的基本原理和理论公式,掌握用热力学解决化工以及与化工有关的技术问题的方法和理论知识。化工以及与化工有关的技术问题的方法和理论知识。第23页,本讲稿共34页 第一章第一章 热力学基础热力学基础 主要讲解敞开体系主要讲解敞开体系热力学第一定律和第二定律的应用热力学第一定律和第二定律的应用热力学第一定律
23、和第二定律的应用热力学第一定律和第二定律的应用、热力学体系平衡判据的建立及其在膜平衡、相平衡和热力学体系平衡判据的建立及其在膜平衡、相平衡和化学反应平衡中的应用。化学反应平衡中的应用。第24页,本讲稿共34页第第第第二二二二章章章章 统统统统计计计计热热热热力力力力学学学学基基基基础础础础 (The The elements elements of of statistical statistical thermodynamicsthermodynamics)重点介绍量子力学基础和统计热力学基础,以及应用统重点介绍量子力学基础和统计热力学基础,以及应用统计热力学知识进行简单体系热力学性质计算。
24、计热力学知识进行简单体系热力学性质计算。第25页,本讲稿共34页 第三章第三章 流体状态方程流体状态方程(The Equations of State for Fluids)重点讲解立方型状态方程及其混合规则。重点讲解立方型状态方程及其混合规则。第26页,本讲稿共34页 第四章第四章 纯流体热力学性质纯流体热力学性质(The Thermodynamic Properties of Pure Fluids)第27页,本讲稿共34页 第第五五章章 溶溶液液热热力力学学性性质质(The Thermodynamic properties of Solutions)第28页,本讲稿共34页 第第六六章章
25、 活活度度系系数数模模型型(The Models of Activity Coefficients)重点介绍非电解溶液常用的活度系数模型重点介绍非电解溶液常用的活度系数模型 。第29页,本讲稿共34页 第七章第七章 相平衡相平衡(Phase Equilibrium)第30页,本讲稿共34页教教 材材第31页,本讲稿共34页许文,高等化工热力学许文,高等化工热力学,天津大学出版社,天津大学出版社,2004。第32页,本讲稿共34页参考资料参考资料第33页,本讲稿共34页1 Jefferson W.Tester and Michael Modell,Thermodynamics and Its Application,3rd Edition,Prentice Hall PTR.1997.2 J.M.Smith,H.C.Van Ness,and M.M.Abbott,Introduction to Chemical Engineering Thermodynamics,6th Edition.McGraw-Hill Companies,Inc.2001.3 胡英胡英,近代化工热力学近代化工热力学,上海科学技术文献出版社上海科学技术文献出版社,1994.第34页,本讲稿共34页
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