# Lecture 21 - PowerPoint PPT Presentation

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Lecture 21. 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. Today’s lecture. CSTR With Heat Effects Multiple Steady States Ignition and Extinction Temperatures.

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Lecture 21

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## Lecture 21

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.

### Today’slecture

• CSTR With Heat Effects

• Ignition and Extinction Temperatures

### CSTR with Heat Effects

Courtesy of Pfaudler, Inc.

Neglect

Using

We obtain after some manipulation:

Collecting terms with and high coolant flow rates,and

If G(T) > R(T) TemperatureIncreases

If R(T) > G(T) TemperatureDecreases

Solving for X.

Solving for X

Solving for T

### Energy balance for CSTRs

Increasing T0

R(T)

Variation of heat removal line with inlettemperature.

T

Energy balance for CSTRs

κ=∞

R(T)

κ=0

T0

Increase κ

Ta

T

Variation of heat removal line with κ (κ=UA/CP0FA0)

1) Mole Balance:

2) Rate Law:

3) Stoichiometry:

4) Combine:

Variation of heat generation curve with space-time.

Finding Multiple Steady States with T0 varied

Finding Multiple Steady States with T0 varied

Temperature ignition-extinction curve

Stability of multiple state temperatures

MSS - Generating G(T) and R(T)

Need to solve for X after combining mole balance rate law and stoichiometry.

MSS - Generating G(T) and R(T)

For a first order irreversible reaction

Parameters

Thenplot G and R as a function of T.