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Chemical Reaction Engineering

Chemical Reaction Engineering

Chemical Engineering

1

Chemical Reaction EngineeringChemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place.

Chemical reaction engineering is at the heart of virtually every chemical process. It separates the chemical engineer from other engineers.

Industries that Draw Heavily on Chemical Reaction Engineering (CRE) are:

CPI (Chemical Process Industries)Dow, DuPont, Amoco, Chevron

Lets Begin CREChemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place.

A chemical species is said to have reacted when it has lost its chemical identity.

Chemical Identity

A chemical species is said to have reacted when it has lost its chemical identity.

The identity of a chemical species is determined by the kind, number, and configuration of that species atoms.Chemical Identity

A chemical species is said to have reacted when it has lost its chemical identity.

1. DecompositionChemical Identity

A chemical species is said to have reacted when it has lost its chemical identity.

1. Decomposition2. Combination Chemical Identity

A chemical species is said to have reacted when it has lost its chemical identity.

1. Decomposition2. Combination 3. Isomerization Chemical Identity

The reaction rate is the rate at which a species looses its chemical identity per unit volume.

Reaction Rate

The reaction rate is the rate at which a species looses its chemical identity per unit volume.The rate of a reaction (mol/dm3/s) can be expressed as either

the rate of Disappearance: -rA or as the rate of Formation (Generation): rA

Reaction Rate

Reaction RateConsider the isomerization ABrA = the rate of formation of species A per unit volume -rA = the rate of a disappearance of species A per unit volume rB = the rate of formation of species B per unit volume

Reaction RateEXAMPLE: AB If Species B is being formed at a rate of 0.2 moles per decimeter cubed per second, ie,

rB = 0.2 mole/dm3/s

Reaction RateEXAMPLE: AB rB = 0.2 mole/dm3/s

Then A is disappearing at the same rate:

-rA= 0.2 mole/dm3/s

Reaction RateEXAMPLE: ABrB = 0.2 mole/dm3/s

Then A is disappearing at the same rate:-rA= 0.2 mole/dm3/s

The rate of formation (generation of A) is rA= -0.2 mole/dm3/s

Reaction RateFor a catalytic reaction, we refer to -rA', which is the rate of disappearance of species A on a per mass of catalyst basis. (mol/gcat/s)

NOTE: dCA/dt is not the rate of reaction

Reaction RateConsider species j: rj is the rate of formation of species j per unit volume [e.g. mol/dm3/s]

Reaction Raterj is the rate of formation of species j per unit volume [e.g. mol/dm3*s]

rj is a function of concentration, temperature, pressure, and the type of catalyst (if any)

Reaction Raterj is the rate of formation of species j per unit volume [e.g. mol/dm3/s] rj is a function of concentration, temperature, pressure, and the type of catalyst (if any)

rj is independent of the type of reaction system (batch reactor, plug flow reactor, etc.)

Reaction Raterj is the rate of formation of species j per unit volume [e.g. mol/dm3/s] rj is a function of concentration, temperature, pressure, and the type of catalyst (if any) rj is independent of the type of reaction system (batch, plug flow, etc.)

rj is an algebraic equation, not a differential equation

General Mole Balance

General Mole Balance

Batch Reactor Mole Balance

CSTRMole Balance

Plug Flow Reactor

Plug Flow Reactor Mole BalancePFR:

The integral form is:

This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to theexit molar flow rate of FA.

Packed Bed Reactor Mole BalancePBR

The integral form to find the catalyst weight is:

Reactor Mole Balance Summary

Fast Forward to the Future Thursday March 20th, 2008

Reactors with Heat Effects

Production of Propylene Glycol in an Adiabatic CSTR

What are the exit conversion X and exit temperature T?SolutionLet the reaction be represented by

KEEPING UP

Separations These topics do not build upon one anotherFiltrationDistillationAdsorption

Reaction EngineeringThese topics build upon one another Mole BalanceRate LawsStoichiometry

Mole BalanceRate LawsStoichiometryIsothermal DesignHeat Effects

Mole BalanceRate Laws

Mole BalanceRate LawsStoichiometryIsothermal DesignHeat Effects

Batch Reactor Mole Balance

Batch Reactor Mole Balance

Batch Reactor Mole Balance

Batch Reactor Mole Balance

Batch Reactor Mole Balance

Continuously Stirred Tank Reactor Mole Balance

Continuously Stirred Tank Reactor Mole Balance

Continuously Stirred Tank Reactor Mole Balance

C S T R Mole Balance

CSTRMole Balance

Plug Flow Reactor

Plug Flow Reactor Mole BalancePFR:

Plug Flow Reactor Mole BalancePFR:

Plug Flow Reactor Mole BalancePFR:

Plug Flow Reactor Mole BalancePFR:

Plug Flow Reactor Mole BalancePFR:

Plug Flow Reactor Mole BalancePFR:

The integral form is:

Plug Flow Reactor Mole BalancePFR:

The integral form is:

This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to theexit molar flow rate of FA.

Packed Bed Reactor Mole BalancePBR

Packed Bed Reactor Mole BalancePBR

Packed Bed Reactor Mole BalancePBR

Packed Bed Reactor Mole BalancePBR

Packed Bed Reactor Mole BalancePBR

The integral form to find the catalyst weight is:

Reactor Mole Balance Summary

Reactor Mole Balance Summary

Reactor Mole Balance Summary

Reactor Mole Balance Summary

Chemical Reaction Engineering

Asynchronous Video Series Chapter 1:General Mole Balance Equation Applied to Batch Reactors, CSTRs, PFRs, and PBRs

H. Scott Fogler, Ph.D.

http://www.engin.umich.edu/~cre

Chemical Reaction EngineeringChemical reaction engineering is at the heart of virtually every chemical process. It separates the chemical engineer from other engineers.

Industries that Draw Heavily on Chemical Reaction Engineering (CRE) are:

CPI (Chemical Process Industries)Dow, DuPont, Amoco, Chevron

Pharmaceutical Antivenom, Drug Delivery

Medicine Tissue Engineering, Drinking and Driving

Compartments for perfusionPerfusion interactions between compartments are shown by arrows.

VG, VL, VC, and VM are -tissue water volumes for the gastrointestinal, liver, central and muscle compartments, respectively.

VS is the stomach contents volume.

StomachVG = 2.4 lGastrointestinalVG = 2.4 ltG = 2.67 minLiver

AlcoholVL = 2.4 l tL = 2.4 minCentralVC = 15.3 l tC = 0.9 minMuscle & FatVM = 22.0 l tM = 27 min

Chemical Reaction EngineeringChemical reaction engineering is at the heart of virtually every chemical process. It separates the chemical engineer from other engineers.

Industries that Draw Heavily on Chemical Reaction Engineering (CRE) are:

CPI (Chemical Process Industries)Dow, DuPont, Amoco, Chevron

Pharmaceutical Antivenom, Drug Delivery

Medicine Pharmacokinetics, Drinking and Driving

Microelectronics CVD

The end

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