CENG 211 Reaction and Reactor Engineering

 

Lecturer:     Dr. Xijun Hu (Room 4557; Tel: 2358 7134;

Email: kexhu; web: http://ihome.ust.hk/~kexhu)

              

Aims:

·       To understand the basic concepts and principles homogeneous and heterogeneous reaction processes

·       To develop the skills to solve the reactor design problems

 

Textbook:

Fogler, H.S. “Elements of Chemical Reaction Engineering”, 4th ed., Prentice Hall, 2006.

 

References:

Levenspiel, O., “Chemical Reaction Engineering”, 3rd ed., Wiley, New York, 1999.

Smith, J.M., “Chemical Engineering Kinetics”, 3rd ed., McGraw Hill, 1981.

Lee, H.H., “Heterogeneous Reactor Design”, Butterworth, 1985.

Satterfield, C.N., “Heterogeneous Catalysis in Industrial Practice”, 2nd ed., McGraw Hill, 1991.

 

Assessments:

          Assignments:                          20%

          3 Quizes:                                 30%

          Final Exam:                            50%

 

Course Content

 

UNIT 1: Introduction to Chemical Reaction Engineering

   Module 1: General introduction

·      General definition; importance of the subject.

·      Overall plan.

   Module 2: Review of the concepts of reaction kinetics

·      Classification of chemical reaction systems.

·      Concepts of reaction rate constant, reaction order, molecularity.

·      Elementary and non-elementary reactions, multiple reaction: parallel/series.

·      Examples illustrating the basic concepts of activation energy.

·      Definition of conversion and mole balance equation.

 

UNIT 2: Homogeneous System/Homogeneous Reactor Design

   Module 1: Isothermal reactors design

·      Single ideal reactors: CSTR, batch, plug flow reactors. Stoichiometry relationship. Analysis of total pressure data obtained in a constant-volume system.

·      Reaction rate law expressed as a function of conversion. Concept of space velocity and residence time.

·      Multiple reactor system. CSTR and plug flow reactors in series/parallel, different size and type.

·      General design structure of isotheral reactors.

   Module 2: Collection and analysis of rate data

·      Batch reactor data: differential and integral methods.

·      Method of initial rates.

·      Method of half lives.

·      Evaluation of laboratory reactors.

·      Experimental design. Examples.

   Module 3: Non-isothermal reactors design

·      Thermodynamics of chemical reactions: heat of reaction, chemical equilibrium.

·      Energy balance of CSTR, plug flow and batch reactors at steady state. Adiabatic and non-adiabatic design.

·      Multiple steady states. Heat removed and heat generated in CSTR. Ignition and extinction curves.

·      Equilibrium conversion: adiabatic temperature and equilibrium conversion. Optimum feed temperature and progression.

·      Multistage non-isothermal operation, cold-shot cooling.

   Module 4: Non ideal reactors

·      Distribution of residence times (RTD) for chemical reactors, pulse input, tracer experiments.

·      Characteristic of RTD integral relationship, mean residence time, normalized RTD function, integral age distribution.

·      RTD and chemical reactors: CSTR and plug flow.

·      Analysis of non-ideal reactors: modeling real reactors with combination of ideal reactors, model of CSTR and tubular reactors, segregation and dispersion model.

 

 

UNIT 3: Heterogeneous System/Heterogeneous Reactor Design

   Module 1: Introduction of catalytic system

·      Definition of catalysts. Properties and principal reactions.

·      Concept of physical and chemical adsorption on solid surface and their importance in catalysis.

·      Requirements for an industrial catalyst.

   Module 2: Kinetics of catalytic reactions

·      Dependence of reaction rate on surface area and gas volume.

·      Mechanism of a catalytic reaction: adsorption isotherm, surface reaction, desorption. Rate limiting step.

·      Synthesizing a rate law mechanism and rate limiting step. Examples.

·      Evaluation of the rate law parameters. Deducing and finding a mechanism from experimental observation. Examples.

 


 Module 3: Diffusion and reaction in porous media

·      Importance and origin of catalyst pore structure. Experimental methods for investigating pore structure.

·      Reaction regimes. Mass transport of gases through pellet.

·      Diffusion and reaction in catalyst pellet. Derivation of the first order differential equation.

·      Internal effectiveness factor. The effect of intrapellet mass transfer on observed rates.

·      Effect of external diffusion on heterogeneous reactions. Overall effectiveness factor.

·      Estimation of diffusion and reaction on limited regimes. Weisz-Prater criterion for internal diffusion. Mears criterion for external diffusion.

   Module 4: Catalyst deactivation

·      General mechanism of catalyst deactivation. Concept of chemical physical deactivation and sintering.

·      Kinetics, mechanism and regeneration.

·      Finding the mechanism of decay from experiment.

·      The importance of catalyst deactivation at industrial scale. Examples.

   Module 5: Design of catalytic reactors

·      Commercially significant types of heterogeneous catalytic reactors. Advantages and disadvantages.

·      Design of a fixed bed reactor. Reactor modeling: one and two dimensional models.

·      Design of a moving bed reactor.

·      Design of a fluidized bed reactor.