Introduction to mass and heat transfer Yeon Ho Im yeonhoim@jbnu.ac.kr Course description The subjects of energy transport (heat conduction, convection, and radiation), and mass transport (diffusion, and convection) will be presented for each topic. Process engineers will also take lessons on how to analyze and solve problems occurring in cutting edge technologies of chemical processes. Main textbooks 1. S. Middlman, An Introduction to Mass and Heat Transfer : Principles of Analysis 이번Inc. 학기에 and Design, 1998, John Wiley and Sons, Reference Books 1. W. L. McCabe, J. C. Smith, Peter Harriot, Unit Operation of Chemical Engineering, McGraw-Hill, 2005 2. R.B.Bird, W.E.Stewart, and E. N.Lightfoot, Transport Phenomena, Second Edition, 2005, John Wiley and Sons, Inc. 3. C. J. Geankoplis, Transport Processes and Separation Process Principles, Fourth Edition, 2003, Prentice Hall. 4. J.D.Seader and E. J. Henley, Separation Process Principles, Second Edition, 2006, John Wiley and Sons, Inc. Chemical Engineering • • No universally accepted de nition of ChE. However, aimed towards design of processes that change materials from one form to another more useful (and so more valuable) form, economically, safely and in an environmentally acceptable way. Application of basic sciences (math, chemistry, physics & biology) and engineering principles to the development, design, operation & maintenance of processes to convert raw materials to useful products and improve the human environment. Chemistry Mathematics Air Natural Gas Coal Minerals Energy fi • Economics Physics Biology First Paradigm : Unit Operations First Paradigm : Unit Operations • Arthur D. Little, industrialist and chair of visiting committee of chemical engineering at MIT, wrote report in 1908 –“Unit Operations should be the foundation of chemical engineering” First textbook Walker-Lewis-McAdams “Principles of Chemical Engineering” 1923 • fi From its beginning chemical engineering was tailored to ful ll the needs of the chemical industry which, in the USA, was mostly based on petroleum derived feedstocks. Competition between manufacturers was brutal, and all strove to be the "low cost producer." However, to stay ahead of the pack chemical plants had to be optimized. This necessitated things such as; continuously operating reactors (as opposed to batch operation), recycling and recovery of unreacted reactants, and cost effective puri cation of products. These advances in-turn required plumbing systems (for which traditional chemists where unprepared) and detailed physical chemistry knowledge (unbeknownst to mechanical engineers). The new chemical engineers were capable of designing and operating the increasingly complex chemical operations which were rapidly emerging. fi • First Paradigm : Unit Operations Momentum, Heat and Mass Transfer • In transforming matter from inexpensive raw materials to highly desired products, chemical engineers became very familiar with the physical and chemical operations necessary in this metamorphosis. Examples of this include: ltration, drying, distillation, crystallization, grinding, sedimentation, combustion, catalysis, heat exchange, coating, and so on. • The "unit operations" concept had been latent in the chemical engineering profession ever since George Davis had organized his original 12 lectures around the topic. But, it was Arthur Little who rst recognized the potential of using “Unit Operations" to separate chemical engineering from other professions “Civil Engineers use it in water/ wastewater treatment”. While mechanical engineers focused on machinery, and industrial chemists concerned themselves with products, and applied chemists studied individual reactions, no one, before chemical engineers, had concentrated upon the underlying processes common to all chemical products, reactions, and machinery. The chemical engineer, utilizing the conceptual tool that was unit operations, could now make claim to industrial territory by fi showing his or her uniqueness and worth to the chemical manufacturer. fi • First Paradigm : Unit Operations Momentum (Fluid Mechanics), Heat and Mass Transfer First Paradigm : Unit Operations Momentum (Fluid Mechanics), Mass and Heat Transfer Diffusion vs. Convection First Paradigm : Unit Operations Momentum (Fluid Mechanics), Mass and Heat Transfer Diffusion vs. Convection https://www.youtube.com/watch?v=o4gpt-5YHLg First Paradigm : Unit Operations Momentum (Fluid Mechanics), Mass and Heat Transfer Example : Distillation Example : Biochemical engineering Example : Filtration Example : Distillation Example : Polymer engineering Solvent evaporation Polymer solution First Paradigm : Unit Operations Momentum (Fluid Mechanics), Mass and Heat Transfer First Paradigm : Unit Operations Momentum (Fluid Mechanics), Mass and Heat Transfer https://www.youtube.com/watch?v=NKZSImhSn6k First Paradigm : Unit Operations Momentum (Fluid Mechanics), Mass and Heat Transfer Example : Heat exchanger Example : Packed bed reactor Example : Batch reactor T Ta Second Paradigm : Transport Phenomena • World War II creation of new technologies by scientists without engineering education: atomic bomb, radar. • Engineering students needed to master new concepts and tools in chemistry and physics. • Unit Operations no longer created streams of exciting new research problems that were challenging to professors and students, and useful in industry. • First textbook “Transport Phenomena” by Bird-Stewart-Lightfoot, 1960, based on kinetic theory of gases. • The Engineering Science movement became dominant in the US, and taught at all the leading universities. • AIChE accreditation requires differential equations, transport phenomena. • Research funding agencies and journals turn their backs on empirical and qualitative research as “old fashioned”. Second Paradigm : Transport Phenomena Momentum (Fluid Mechanics), Mass and Heat Transfer A blood vessel, embedded in a biological tissue, is deformed during the flow of blood through pressure applied to the internal surfaces. Momentum, Mass and Heat Transfer fi (a) Macroscopic level consider a set of e q u a t i o n s c a l l e d t h e “ m a c ro s c o p i c balances”. In studying an engineering, it is a good idea to start with this macroscopic description in order to make a global assessment of the problem. (b) Microscopic level consider a set of equations which describe how the mass, momentum, energy change within this small region. The aim here is to get information about velocity, temperature, pressure, and concentration pro les within the system. (c) Molecular level pursuits a fundamental understanding of the mechanisms of mass, momentum, energy transport in terms of molecular structure and intermolecular forces. Unit operations Transport Phenomena Analogy among Momentum, Mass and Heat Transfer Type of transport Momentum Energy Mass Transport by molecular motion Viscosity and momentum flux Thermal conductivity and the heat flux Diffusivity and the mass flux General transport equations Equation of change and their use including computerAided analysis Equation of change and their use including computer-aided analysis Equation of change and their use including computeraided analysis Transport across phase boundaries Friction factor; Use of empirical correlations Heat-transfer coefficients; use of empirical correlations Mass-transfer coefficients ; use of empirical correlations Transport in large system, such as pieces of equipment Macroscopic balances [ Isothermal ] Macroscopic balances [Nonisothermal ] Macroscopic balances [ mixtures ] 21 century cutting -edge technology 21 century cutting -edge technology Polysilicon Manufacturing Issues 21 century cutting -edge technology Semiconductor & Display Process 21 century cutting -edge technology Reactor system of nanoparticle synthesis 21 century cutting -edge technology Reactor system of nanoparticle synthesis Unit cell of NaAlH4 Conceptual image of solid-state hydrogen tank Ref. MBN Nanomaterialia [Website], “Hydrogen tank”, (2018. Aug 17), http://www.mbn.it/eng/index.php (a) system #1 (b) system #2 (c) system #3 (d) system #4 (a) system #1 (b) system #2 (c) system #3 (d) system #4 Ref. Chem tube 3D, University of Liverpool [Website], “NaAlHx”. (2018. Aug 17). http://www.chemtube3d.com/solidstate/SS-NaAlHx.htm Hydrogen storage and temperature for small system’s simulation results with different geometry
