Ref 8 chemical reaction engineering

Chemical Reaction EngineeringReaction Mechanism and Kinetics Catalyst and Reactor Design Material, Energy and Momentum Balances Chemical engineering processes, Thermodynamics and fluid

Chemical Reaction Engineering

Reaction Mechanism and Kinetics

Catalyst and Reactor Design

Material, Energy and Momentum Balances

Chemical engineering processes, Thermodynamics and fluid mechanics

Transport Kinetics

Mass and heat transfer

Scale-up

Scale-up of technical reactor

Reactor Operation and Control

Control of reactor processes

atomic level pellet level laboratory level production level atomic level pellet level laboratory level production level

(RO)2 Si Si(OR)2

Si OSi SiO SiO

Si OSi SiO

Si OSi SiO

Si OSi SiO

Si OSi SiO

Si OSi SiO SiO

Si OSi SiO SiO

Si OSi SiO

Si OSi SiO

agglomerates powder

Chemical Transformation -2

Sol-gel Process

Silica nanoparticles

Crystallization?

Solar Energy Conversion in Chloroplast

Catalyst speed up the rate of reaction by lowering the activation

energy (Ea)

It does not change the thermodynamics of the reaction,

It equally speed up the forward and reverse reactions,

It may undergo transformation during reaction, but is not

consumed by the reaction

(1.5) What are the other characteristics of a catalyst?

Reactions occurs on the catalyst surface, therefore

a large surface area is advantageous

Surface: XPS, AES, SIMS, FTIR

Localized: EDXS, EPM

Electronic

ESR, UV-Vis, IR, XPS

Screening Combinatorial screening Laboratory Reactor Batch, differential and integral In-situ Reaction

Reaction conducted under direct observation

CENG 511 (Spring 04)

Sintering Clay Intercalation Microfabrication Thin film processes Polymerization Chemical Grafting Ligand Chemistry Enzyme and Proteins Etc…

Biological Catalysts

Enzymes

Catalase

(1.7) Give five more enzymes and the

reactions that they catalyzes

System

Material Balances

A government population survey of a new town shows that in a year 15,000 people establish residence in the town but during the same year 5000 people moves to the surrounding suburbs 8000 birth and 2000 death was recorded during the year How many people live in the city if the last year population is 350,000 people How many women in the city if the average male-female ratio is 0.82

Accounts for chemical reaction

Material Balances

Batch Reactor

Experiment conducted using methanol solvent,

Large excess of 1-pentene was used,

Reaction conducted at room temperature.

= k’cA

(1.8) Derive the reaction equation for a second order reversible reaction (A

to 2B) Plot CA/CA0vs reaction time

Material Balances

Determine the concentration of 1-epoxypentene product

Batch Reactor

Energy Balances

General Energy Balance Equation for Batch Reactor

Heat of Reaction Sensible Heat

Expansion term Latent Heat

Energy Balances

General Energy Balance Equation for Batch Reactor

Heat of Reaction Sensible Heat

Expansion term Latent Heat

Energy Balances

Heat of Reactions

Heat associated breaking and forming of chemical bonds in a molecule

Energy Balances

Standard Heat of Combustion

Energy Balances

Constant Pressure

Energy Balances

Constant Volume (Ideal Gas)

(2.1) Derive the above equation from the general energy balance equation for a batch reactor

Energy Balances

Constant Volume vs Constant Pressure

Energy Balances

Liquid phase batch reactor – 1

The exothermic elementary liquid phase reaction:

was carried out in a batch reactor with a cooling coil to keep the reactor isothermal at 27C The reactor was filled with 2 mol/L of reactant A

(a) How long does it take to reach 95 % conversion?

(b) What is the total amount of heat (kcal) removed by the cooling coil when this conversion is reached?

(c) What is the maximum rate by which the heat must be removed by the heating coil (kcal/min) and at what time does this maximum occurs?(d) What is the adiabatic temperature rise for this reactor and its

significance?

Energy Balances

Additional information:

Liquid phase batch reactor – 2

(2.2) Repeat the calculation for a second order irreversible reaction:

Energy Balances

Adiabatic Heating and Temperature Rise

.

0 100 200 300

Why study chemical reaction equilibrium when operating reactors

are never at chemical equilibrium?

Chemical Reaction Equilibrium

(1) Determine the limits of reactor performance,

(2) Explore possible design and operation changes that overcomes

these restriction and optimizes reactor performance

Thermodynamics

Gibbs Energy (∆G)

Physical and Chemical Precondition for Biochemical Reactions

including Cell Metabolism and Enzymatic Catalysis

∆G < 0 Spontaneous, Energy releasing process –Exergonic Process

∆G = 0 Equilibrium process

∆G > 0 Non-spontaneous, Energy consuming process – Endergonic Process

Energy (Photon, Heat)

Nutrient (Reduced molecules)

cell metabolism

STORED ENERGY

Condition for Reaction Equilibrium

The Gibbs free energy:

Extend of Reaction

Thermodynamics

Condition for Reaction Equilibrium

The Gibbs free energy:

Extend of Reaction

Condition for Reaction Equilibrium

Necessary condition for reaction equilibrium

Standard Gibbs energy

activity fugacity

Thermodynamics

Condition for Reaction Equilibrium

The Gibbs free energy for a reaction system:

Standard Gibbs energy

of change

Equilibrium constant

Ideal Gas Equilibrium – 1

High octane fuel additives are produced by reaction of isobutane with 1-butene hydrocarbons:

Determine the equilibrium composition of the reaction mixture at a pressure of 2.5 atm and temperature of 400 K The standard Gibbs

energy change for this reaction at 400 K is –3.72 kcal/mol

Assume that equimolar amounts of isobutane and 1-butene are present

in the initial mixture

(2.3) Please repeat the calculation if the initial ratio of I/B = 100, 10, 0.1