0
TECHNICAL PAPERS

Effect of Atomization Method on the Morphology of Spray-Generated Particles

[+] Author and Article Information
Morteza Eslamian

Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road Toronto, ON, Canada M5S 3G8

Nasser Ashgriz1

Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road Toronto, ON, Canada M5S 3G8ashgriz@mie.toronto.edu

1

Corresponding author.

J. Eng. Mater. Technol 129(1), 130-142 (Sep 08, 2006) (13 pages) doi:10.1115/1.2400270 History: Received September 24, 2005; Revised September 08, 2006

Effect of various atomization methods and solute concentration on the morphology of spray dried magnesium sulphate particles is investigated. Four types of atomizers are characterized and tested including (i) a vibrating mesh nebulizer, (ii) a splash plate nozzle, (iii) an air mist atomizer, and (iv) a pressure atomizer. Several types of particle morphologies are identified in this research. Spray characteristics, such as droplet number density, droplet size, and velocity, and accompanying atomizing air have major influence on the drying and morphology of the particles. High initial solute concentrations result in the formation of thick-walled particles, and this prevents the particles to burst. It is found to be difficult to obtain fully filled magnesium sulphate particles, even for saturated solutions at room temperature because the solution equilibrium saturation changes substantially with temperature.

Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Basic processes of spray drying and pyrolysis. In spray pyrolysis after crust formation, if the reactor temperature is high enough, then a chemical decomposition may occur in the droplet.

Grahic Jump Location
Figure 2

Experimental setup

Grahic Jump Location
Figure 3

A schematic of the phase Doppler particle analyzer (PDPA) system

Grahic Jump Location
Figure 4

(a) A schematic of the vibrating mesh nebulizer, (b) a spray image using laser sheet lighting in open atmosphere, (c) droplet diameter histogram, and (d) droplet velocity histogram, for a 1M solution of magnesium sulphate at 2cm from the mesh plate. Droplet mean size dave and droplet mean velocity vave are shown on the plots.

Grahic Jump Location
Figure 5

SEM images of the particles produced from a 0.7M solution of magnesium sulphate by spray drying, using a vibrating mesh nebulizer; (a) and (b) show population of the particles, (c) a hollow, but very thick-walled particle, and (d) a cracked particle

Grahic Jump Location
Figure 6

SEM images of the particles produced from a 1M solution of magnesium sulphate by spray drying, using a vibrating mesh nebulizer; (a)–(c) particle morphologies at different magnifications; (d) two particles with holes among the other particles

Grahic Jump Location
Figure 7

(a) A schematic of the splash plate nozzle, (b) an image of the resulting spray using laser sheet lighting, (c) droplet diameter histogram, and (d) droplet velocity histogram for a 1M solution of magnesium sulphate at 2cm from the center of the nozzle. Droplet average size dave and droplet average velocity vave are shown on the plots

Grahic Jump Location
Figure 8

SEM images of the particles produced from a 0.7M solution of magnesium sulphate by spray drying, using a splash plate atomizer; (a) shows population of the particles, (b) contracted particles, (c) smooth surface particle with a hole, and (d) a nondisrupted particle

Grahic Jump Location
Figure 9

SEM images of the particles produced from a 1M solution of magnesium sulphate using the splash plate atomizer; (a) shows population of the particles, (b) a broken particle among several contracted particles, and (c) and (d) orderly disrupted particles among the contracted particles

Grahic Jump Location
Figure 10

SEM images of the particles produced from a 2.8M solution of magnesium sulphate by spray drying, using a splash plate atomizer; (a) and (b) particles morphologies at two different magnifications, (c) a contracted particle next to a smooth surface particle, and (d) different types of particles and a half shell

Grahic Jump Location
Figure 11

(a) A schematic of the air mist atomizer, (b) an image of the resulting spray, using laser sheet lighting, (c) droplet diameter histogram, and (d) droplet velocity histogram, for a 1M solution of magnesium sulphate at 2cm from the center of the nozzle. Droplet average size dave, and droplet average velocity vave are shown on the plots.

Grahic Jump Location
Figure 12

SEM images of the particles produced from a 0.7M solution of magnesium sulphate by spray drying, using an air mist atomizer; (a) contracted and smooth-surface particles, (b) disrupted particle, (c) orderly disrupted particle, and (d) disrupted particle

Grahic Jump Location
Figure 13

SEM images of the particles produced from a 1M solution of magnesium sulphate by spray pyrolysis, using an air mist atomizer; (a)–(c) particles at different magnifications and (d) several half-shell particles among the other particles

Grahic Jump Location
Figure 14

SEM images of the particles produced from a 2.8M solution of magnesium sulphate by spray drying, using the air mist atomizer; (a) and (b) particle morphologies at two different magnifications, (c) smooth-surface nondisrupted particle, (d) contracted particle

Grahic Jump Location
Figure 15

(a) A schematic of the pressure atomizer: the liquid swirls inside the nozzle, (b) an image of the resulting spray, using laser sheet lighting, (c) droplet diameter histogram, and (d) droplet velocity histogram, for a 1M solution of magnesium sulphate at 2cm from the center of the nozzle. Droplet average size dave and droplet average velocity vave are shown on the plots.

Grahic Jump Location
Figure 16

Different possibilities for hollow particle formation during spray drying: (a) Uniform shell disruption, (b) nonuniform shell disruption, (c) contracted shell particle, (d) nondisrupted smooth surface particle, (e) nonuniform shell disruption, and (f) porous particle

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In