**KINETICS & REACTOR**

DESIGN

DESIGN

**chapter 1**

**MOLE BALANCES**

**chapter 2**

**CONVERSION AND REACTOR SIZING**

**RATE LAWS AND STOICHIOMETRY**

**chapter 3**

general mole balance equation

IN - OUT + GENERATION = ACCUMULATION

Batch reactor

Continuous-Stirred Tank Reactor

Plug flow

reactor

Packed bed

reactor

types of reactors

fixed volume

continuous

flow

Mole balance

Reactor

Batch

CSTR

PFR

PBR

Conversion, X, is the moles of A

reacted per mole A feed.

Batch system

X=

N -N

A0 A

N

AO

Flow system

X=

F -F

F

A0 A

A0

For reactors in series with no side streams

X =

total moles of A reacted up to point i

moles A fed to the first reactor

i

Series of CSTR and PFR

Conversion, X

For

irreversible reactions

, the maximum value of conversion, X, is that for complete conversion, i.e. X=1.0.

For

reversible reactions

, the maximum value of conversion, X, is the equilibrium conversion, i.e. X=Xe.

Batch :

Flow :

Design Equations

Reactor Sizing

Given -rA=f(X), we can size any reactor using

Levenspiel Plot.

Space time

The

Space time

, tau, is obtained by dividing the reactor volume by the volumetric flow rate entering the reactor.

PART 1

**RATE LAWS**

PART 2

STOICHIOMETRY

A

rate law

describes the behavior of a reaction. The

rate of a reaction

is a function of temperature (through the rate constant) and concentration.

RELATIVE RATES OF REACTION

POWER LAW MODEL

RATE CONSTANT, k

Elementary Rate Laws

A reaction follows an elementary rate law if and only if the (iff) stoichiometric coefficients are the same as the individual reaction order of each species.

eg : Rate law for

would be

Non-elementary Rate Laws

then the reaction is said to be 2nd order in A, 1st order in B, and 3rd order overall.

If rate law for non-elementary reaction

is

REVERSIBLE REACTIONS

The net rate of formation of any species is equal to its rate of formation in the forward reaction plus its rate of formation in the reverse reaction:

At equilibrium, ratenet=~ 0 and the rate law must reduce to an equation that is thermodynamically consistent with the equilibrium constant for the reaction.

To set up stoichiometry tables, we use A as our basis of calculation. C = f(x) is combined with rate law to obtain -r =f(x)

A

BATCH SYSTEM

STOICHIOMETRIC TABLE

FLOW SYSTEM

Flow gas phase

FLOW SYSTEM

STOICHIOMETRIC TABLE

i

**chapter 4**

**MOLE BALANCES**

Solution Conversion Algorithm

1. Mole balance and design equation

2. Rate Law

3. Stoichiometry

4. Combine

5. Evaluate

A. Graphically

B Numerical

C. Analytical

D. Software Packages

Measures other than Conversion

1. Gases :

2. Liquids :

Membrane Reactors

Mole Balance

Rate Law

Semibatch Reactor