REACTORS By: Shaimaa Soarkati, CHBE446 Section: 0301 A.James Clark School of Engineering By: Shaimaa Soarkati, CHBE446 Section: 0301 A.James Clark School of Engineering

Constant Stirred Tank Reactor (CSTR)  Steady-state continuous flow of reactants (A) and Products (B). Well- mixed reactor, so exit stream has the same composition as reactants in the tank  Phases present:  Liquid, Gas-liquid, Solid-liquid  Advantages:  Continuous process  Maintainable temperature  Simple design  Easy to clean  Low operating cost  Disadvantages:  Low conversion per unit volume  Steady-state continuous flow of reactants (A) and Products (B). Well- mixed reactor, so exit stream has the same composition as reactants in the tank  Phases present:  Liquid, Gas-liquid, Solid-liquid  Advantages:  Continuous process  Maintainable temperature  Simple design  Easy to clean  Low operating cost  Disadvantages:  Low conversion per unit volume

CSTR Equations

Plug Flow Reactor (PFR)  A long reactor tube with consisting of many “plugs”  Concentration changes down the reactor (length-wise)  No radial variation in reaction rate/ concentration  For large scale  Heterogeneous and homogeneous reactions (fast)  Advantages:  High conversion per unit volume  Efficient heat transfer  Continuous process  Easy maintenance  Typically contain catalyst  Disadvantages:  Poor temperature control  Undesired thermal gradients possible  Poor mixing (static mixers)  A long reactor tube with consisting of many “plugs”  Concentration changes down the reactor (length-wise)  No radial variation in reaction rate/ concentration  For large scale  Heterogeneous and homogeneous reactions (fast)  Advantages:  High conversion per unit volume  Efficient heat transfer  Continuous process  Easy maintenance  Typically contain catalyst  Disadvantages:  Poor temperature control  Undesired thermal gradients possible  Poor mixing (static mixers)

PFR Equations

BATCH REACTOR  Reactants are supplied via the top two holes on the reactor and nothing can be added or extracted while the reaction process occurs.  Can be heated or cooled via jacket  Small scale  Used mostly for pharmaceutical or fermentation processes  Advantages:  High conversion per unit volume  Can be used for multiple operations  Easy to clean  Disadvantages:  Varied product quality  High operation cost  Reactants are supplied via the top two holes on the reactor and nothing can be added or extracted while the reaction process occurs.  Can be heated or cooled via jacket  Small scale  Used mostly for pharmaceutical or fermentation processes  Advantages:  High conversion per unit volume  Can be used for multiple operations  Easy to clean  Disadvantages:  Varied product quality  High operation cost

Batch Reactor Equations

Heterogeneous Catalysis  Form of catalysis where the catalyst phase is different from the reactants  Adsorption is an essential first step in heterogeneous catalysis  Molecule in gas phase binds to a liquid or solid surface  Surface Reactions  Langmuir-Hinshelwood mechanism  Rideal-Eley mechanism  Precursor mechanism  Form of catalysis where the catalyst phase is different from the reactants  Adsorption is an essential first step in heterogeneous catalysis  Molecule in gas phase binds to a liquid or solid surface  Surface Reactions  Langmuir-Hinshelwood mechanism  Rideal-Eley mechanism  Precursor mechanism