CRE is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place Lecture 18 Web Lecture 18 Class Lecture 23 Tuesday 452011 ID: 640858
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Slide1
Chemical 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.
Lecture 18Slide2
Web Lecture 18Class Lecture 23 – Tuesday 4/5/2011
Catalytic Mechanisms
Data Analysis
Chemical Vapor Deposition
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(a) The initial rate of reaction is shown below (A) (B)
(C)
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Where K
A
= 4
atm
–1
and K
C = 6
atm–11) At what is the ratio of sites with A adsorbed to those sites with C adsorbed when the conversion is 50%?
2) What is the conversion when the sites with A adsorbed are equal to those with C adsorbed?Slide9
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1) At X = 0.5
2) At an equal concentrations of A and C sites, the conversion will be Slide11
Dimethyl
Either
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Initially water does not exit the reactor the same as DME because
Which of the following best describes the data
A
There is more DME than water.
B
Steady state has been reached.
C
Water reacts with ME.
D
Water is adsorbed on the surface.Slide12
Dimethyl
Either
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Which of the following are true
The concentration of DME reaches a maximum because
A
the rate of reaction is very rapid initially.
B
all the sites are vacant initially so that (Methanol) ME is rapidly adsorbed.
C
there is very little water initially adsorbed on the surface.
D
DME is probably not on the surface.Slide13
Chemical Reaction Engineering in the Electronics Industry Slide14
Chemical Reaction Engineering in the Electronics Industry
ChE
342
Czochralski
Crystal Growth – Heat Transfer
Doping of n/p junction – DiffusionChE 344
Chemical Vapor Deposition (Catalysis Analogy) Photo Resist Formation Photo Resist Dissolution EtchingThe 5 steps 1. Postulate Mechanism (sometimes first includes a gas phase reaction( then adsorption, surface reaction and desorption)
2. Postulate Rate Limiting Step 3. Evaluate Parameters in Terms of Measured Variables 4. Surface Area Balance 5. Evaluate Rate Law ParametersSlide15
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Chemical Vapor
DespositionSlide17
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Chemical Vapor
Desposition
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1) Mechanism
Gas Phase
Homogeneous
HeterogeneousSlide19
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2) Rate Limiting Step
3) Express
f
i
in terms of P
i
4) Area BalanceSlide20
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4) Area Balance
5) CombineSlide21
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Homogeneous ReactionSlide22
End of Web Lecture 18
End of Class Lecture 23
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