High temperature aerosol
processing
•
•
•
•
•
•
Overview
Example of TiO2
Vapor phase generators
Spray pyrolysis
Spray generation
Jung Hyeun Kim’s presentation
Aerosol Reactors
• Vapor Phase Reactors - Titania, Fumed
Silica, Nitrides, etc. - Hot Wall, Flame,
Plasma, Laser Ablation, Laser Pyrolysis
• Spray Pyrolysis - Ferrites, Single and
Multicomponent oxides, metals and alloys
- Spray Nozzles - single and two fluid,
Acoustic Sprayers and Nebulizers
Problem Particles
• Process Effluents - Power Plant Fly Ash,
Smelter Emissions, Sintering Plants
• Contaminants - Contamination in
Pharmaceutical, Semiconductor Industries
(Mr. Doug Kremer on Thursday)
• Occupational Exposure
Process Players
• Solid/gas reactors - Reactant Feeding
• Size Classification - Powder Dispersion in
Gases
• Coatings on Surfaces - Condensation
PRODUCTS
• Titania pigment, Carbon blacks, Fumed
silica, Alumina etc.
• Metals and alloys - Ni, Ag, Au, Pd electronics circuits
• Multicomponent Oxides - Ferrites,
Superconductors,Dielectrics
• Nanoscale Materials
Vapor Phase Reactors
•Precursor is in vapor phase
•Chemical reaction to condensable species or
condensation of vapor happens to make products
(can have combination of both)
•Chemically reactive environment can be: flame,
plasma, thermal with resistive heating, thermal
via laser etc…
•Condensation induced by mixing, expansion
(big pressure gradients!) or both
Titania Process
Oxygen
Agglomerates
Flame
Fuel
Fabric Filter
Molecular
Clusters
Thermophoresis Wall Deposits
TiCl4
Product
Titania Process
•
•
•
•
Nucleation - Particle Formation
Coagulation and Aggregate Formation
Thermophoresis and Wall Losses
Solid/Gas Separation - Fabric Filter(Bag
House Collectors)
Agglomeration and Aggregation
Spray Pyrolysis
•Very common method for making particles
•Here precursor starts as droplets or solid
particles
•Thermal, plasma, flame also used as reaction
environment but reaction is in liquid or solid
phase (tiny microreactors!)
•Mr. JH Kim will discuss this…
Droplet Drying and Conversion
•Drying and conversion rates affect
morphology of the particles
•Can have hollow particles or can shatter
particles
•Mr. Kim will talk about effect of solvent on
chemistry of particles
•How to make spray? Some examples…
Video Images of Drying Droplet
Time: 0 sec
Time: 71 sec
Time: 95 sec
Time: 117 sec
Time: 145 sec
Time: 188 sec
Condensation Aerosol Generator
Gas
Condenser
Vaporizer
Heater
Nebulizer
Aerosol
Impaction Target
Nebulizer/Condensation
Generator
Condenser
Evaporator
Nebulizer
Aerosol