# Lecture 1

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

1. Introduction
2. Definitions
3. General Mole Balance Equation
• Batch
• CSTR
• PFR
• PBR

## Applications to Chemical Engineering

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

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.

## 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.

1. Decomposition     CH3CH3→H2+H2C=CH2
2. Combination         N2+O2→2NO
3. Isomerization       C2H5CH=CH2→CH2=C(CH3)2

## 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

Consider the isomerization A\$rarr;B

rA = 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

EXAMPLE: A→B

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

• rj 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

The rate law is an algebraic equation. For example for the reaction, A→B

The rate law could be of the form

## General Mole Balance

Batch Reactor Mole Balance

CSTR Mole Balance

Plug Flow Reactor

Plug Flow Reactor Mole Balance

Packed Bed Reactor Mole Balance

Reactor Mole Balance Summary

## Keeping Up

Reaction Engineering

These topics build upon one another

But if you cut corners like this

Then this will happen

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