Reaction Engineering Lecture 1

8/20/2019 Reaction Engineering Lecture 1

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Chemical Reaction Engineering (CRE) is the field that studiesthe rates and mechanisms of chemical reactions and the design of

the reactors in which they take place.

TODAY’S LECTURE

Introduction

Definitions

General Mole alance E!uation

atch

C"#R $%R

$R









Materials on the e* and CDR+M

http,--www.engin.umich.edu-cre-













De&eloping Critical #hinking "kills

"ocratic /uestioning

is the

0eart of Critical #hinking

R. . $aul1s 2ine #ypes of "ocratic /uestions



3et1s egin CRE

Chemical Reaction Engineering (CRE) isthe field that studies the rates and

mechanisms of chemical reactions and thedesign of the reactors in which they take place.



• chemical species is said to ha&e reacted

when it has lost its chemical identity.

Chemical Identity



• chemical species is said to ha&e reacted when it has lost its chemical

identity.

• #he identity of a chemical species is determined *y the kind ' number '

and configuration of that species1 atoms.

Chemical Identity





4. Decom%osition

Chemical Identity





4. Decomposition

5. Com&ination

Chemical Identity





4. Decomposition

5. Com*ination

6. Isomeri'ation

Chemical Identity



7 #he reaction rate is the rate at which a

species looses its chemical identity per unit

&olume.

Reaction Rate



7 The reaction rate is the rate at which aspecies looses its chemical identity per unit

&olume.

7#he rate of a reaction (mol-dm

6

-s) can *ee8pressed as either

the rate of Disappearance, (rA

or as

the rate of %ormation (Generation), rA

Reaction Rate



Reaction Rate

Consider the isomeri9ation A )

rA * the rate o+ +ormation o+ s%ecies A %er unit olume

(rA * the rate o+ a disa%%earance o+ s%ecies A %er unit olume

r) * the rate o+ +ormation o+ s%ecies ) %er unit olume



Reaction Rate

7 E:M$3E, A )

If "pecies is *eing formed at a rate of

;.5 moles per decimeter cu*ed per second' ie'

r) * ,-. mole/dm0/s



Reaction Rate

7 E:M$3E,

r < ;.5 mole-dm6

-s

Then A is disa%%earing at the same rate$

(rA* ,-. mole/dm0/s



Reaction Rate

7 E:M$3E, A )

r < ;.5 mole-dm6-s

#hen is disappearing at the same rate,

=r (< ;.5 mole-dm6-s

The rate o+ +ormation "generation o+ A# is

rA* (,-. mole/dm0/s



Reaction Rate

7 %or a catalytic reaction' we refer to =r (>'

which is the rate of disappearance of

species on a per mass of catalyst *asis.

(mol-gcat-s)

2+#E, dC(-dt is not the rate of reaction



Reaction Rate

Consider species ?,

7 r 1 is the rate o+ +ormation o+ s%ecies 1 %er

unit olume 2e-g- mol/dm0/s3



Reaction Rate

7 r ? is the rate of formation of species ? per

unit &olume @e.g. mol-dm6AsB

7 r 1 is a +unction o+ concentration4

tem%erature4 %ressure4 and the t!%e o+

catal!st "i+ an!#



Reaction Rate

7 r ? is the rate of formation of species ? per unit

&olume @e.g. mol-dm6-sB

7 r ? is a function of concentration' temperature'

pressure' and the type of catalyst (if any)

7 r 1 is inde%endent o+ the t!%e o+ reaction s!stem"&atch reactor4 %lug +low reactor4 etc-#



Reaction Rate

7 r ? is the rate of formation of species ? per unit&olume @e.g. mol-dm6-sB

7 r ? is a function of concentration' temperature'

pressure' and the type of catalyst (if any)7 r ? is independent of the type of reaction

system (*atch' plug flow' etc.)

7 r 1 is an alge&raic e5uation4 not a

di++erential e5uation



General Mole alance



General Mole alance



atch Reactor Mole alance



C"#R

Mole alance



$lug %low Reactor



$lug %low Reactor Mole alance

PFR:

The integral form is: V =dF

A

rA

FA 0

FA

∫

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

exit molar flow rate of FA.

$acked ed Reactor



$acked ed Reactor

Mole alance

PBR

The integral form to find the catalyst weight is: W =dF

A

′rAFA 0

FA

∫

FA0 −FA + ′rAdW =dNA

dt∫



Reactor Mole alance "ummary



%ast %orward to the %uture

#hursday March 5;th' 5;;

Reactors with 0eat Effects



Production of Propylene Glycol in an Adiabatic

CSTR



What are the exit conversion X and exit temperature T?

Solution

Let the reaction be represented by



















EE$I2G $



"eparations

#hese topics do not *uild upon one another

Filtration Distillation Adsorption



Reaction Engineering

#hese topics *uild upon one another

Mole Balance Rate Laws Stoichiometry



Mole Balance

Rate Laws

Stoichiometry

Isothermal Design

Heat Effects



Mole Balance Rate Laws



Mole Balance

Rate Laws

Stoichiometry

Isothermal Design

Heat Effects

















t h R t M l l




t h R t M l l




t h R t M l l




t h R t M l l




t h R t M l l




Continuously "tirred #ank Reactor




Mole alance





Mole alance





Mole alance

C " # R



C " # R

Mole alance

C"#R



C"#R

Mole alance



$lug %low Reactor





PFR:





PFR:





PFR:





PFR:





PFR:







PFR:

The integral form is: V =dF

A

rA

FA 0

FA

∫

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

exit molar flow rate of FA.

$acked ed Reactor Mole



alance

PBR




alance

PBR


dt∫




alance

PBR


dt∫




alance

PBR


dt∫




alance

PBR

The integral form to find the catalyst weight is: W =dF

A

′rAFA 0

FA

∫


dt∫





































Chemical Reaction Engineering

synchronous Fideo "eries

Chapter 4,

General Mole alance E!uation

pplied toatch Reactors' C"#Rs' $%Rs'

and $Rs

htt%$//www-engin-umich-edu/6cre



















Chemical reaction engineering is at the heart of &irtually

e&ery chemical process. It separates the chemical engineerfrom other engineers.

Industries that Draw Heail! on Chemical ReactionEngineering "CRE# are$

C$I (Chemical $rocess Industries)

Dow' Du$ont' moco' Che&ron

$harmaceutical nti&enom' Drug Deli&ery

Medicine #issue Engineering' Drinking and Dri&ing

Compartments for perfusion



Compartments for perfusion

Perfusion interactions between

compartments are shown by arrows.

V G, V

L, V

C , and V

M are -tissue water

volumes for the gastrointestinal,

liver, central and muscle

compartments, respectively.

V S is the stomach contents volume.

Stomach

VG = 2. l

Gastrointestinal

VG = 2. l

tG = 2.!" min

#iver

$lcohol

V# = 2. l

t# = 2. min

%entral

V% = &'.( l

t% = ).* min

+uscle at

V+ = 22.) l

t+ = 2" min






C e ca eact o g ee g

Chemical reaction engineering is at the heart of &irtually e&ery

chemical process. It separates the chemical engineer from otherengineers.

Industries that Draw Heail! on Chemical ReactionEngineering "CRE# are$

C$I (Chemical $rocess Industries)Dow' Du$ont' moco' Che&ron

$harmaceutical nti&enom' Drug Deli&ery

Medicine $harmacokinetics' Drinking and Dri&ing

Microelectronics CFD



Reaction Rate

Consider the isomeri9ation A

)




Reaction Rate

Consider the isomeri9ation A )


(rA * the rate o+ a disa%%earance o+ s%ecies A %er unit olume




y

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Reaction Engineering Lecture 1