Effect of droplet size distribution on spray drying kinetics

Abstract Previous work showed that particle behaviors in ultrasonic atomization pyrolysis (UAP) reactor have a great influence on the transport and collection of particles. In this study, the effects of droplet behaviors (i.e. droplet collision and breakage) and solvent evaporation on the droplet size, flow field and collection efficiency during the preparation of ZnO particles by UAP were investigated. The collision, breakage and solvent evaporation conditions which affect the droplet size distribution and flow pattern were considered in CFD simulation based on Eulerian-Lagrangian method. The results showed that droplet collision and breakage would increase the droplet size, broaden the droplet size distribution and hinder the transport of droplets. Solvent evaporation obviously changed the flow pattern of droplets. In addition, both droplet behaviors and solvent evaporation reduced the collection efficiency. This study could provide detail information for better understanding the effect of droplet behaviors and solvent evaporation on the particle production process via UAP reactor.

Download Full-text

Predicting Droplet Size Distribution by Image Processing Technique for an Air Blast Atomizer

Drying Technology ◽

10.1080/07373937.2014.915553 ◽

2014 ◽

Vol 32 (14) ◽

pp. 1655-1663 ◽

Cited By ~ 2

Author(s):

Leila Kavoshi ◽

Mohammad S. Hatamipour ◽

Amir Rahimi ◽

Mehdi Momeni

Keyword(s):

Image Processing ◽

Size Distribution ◽

Droplet Size ◽

Droplet Size Distribution ◽

Processing Technique ◽

Image Processing Technique ◽

Air Blast

Download Full-text

Numerical Study toward Optimization of Spray Drying in a Novel Radial Multizone Dryer

Energies ◽

10.3390/en14051233 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1233

Author(s):

Umair Jamil Ur Rahman ◽

Artur Krzysztof Pozarlik ◽

Thomas Tourneur ◽

Axel de Broqueville ◽

Juray De Wilde ◽

...

Keyword(s):

Spray Drying ◽

Droplet Size ◽

Separation Efficiency ◽

Numerical Study ◽

Three Dimensional ◽

Droplet Size Distribution ◽

Vortex Chamber ◽

Temperature Pattern ◽

Multiphase Model ◽

Drying Technology

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.

Download Full-text

Remote sensing of water cloud droplet size distributions using the backscatter glory: a case study

Atmospheric Chemistry and Physics ◽

10.5194/acp-4-1255-2004 ◽

2004 ◽

Vol 4 (5) ◽

pp. 1255-1263 ◽

Cited By ~ 35

Author(s):

B. Mayer ◽

M. Schröder ◽

R. Preusker ◽

L. Schüller

Keyword(s):

Remote Sensing ◽

Size Distribution ◽

Droplet Size ◽

Cloud Droplet ◽

Droplet Size Distribution ◽

Single Scattering ◽

Effective Radius ◽

Radiative Properties ◽

High Angular Resolution ◽

Size Distributions

Abstract. Cloud single scattering properties are mainly determined by the effective radius of the droplet size distribution. There are only few exceptions where the shape of the size distribution affects the optical properties, in particular the rainbow and the glory directions of the scattering phase function. Using observations by the Compact Airborne Spectrographic Imager (CASI) in 180° backscatter geometry, we found that high angular resolution aircraft observations of the glory provide unique new information which is not available from traditional remote sensing techniques: Using only one single wavelength, 753nm, we were able to determine not only optical thickness and effective radius, but also the width of the size distribution at cloud top. Applying this novel technique to the ACE-2 CLOUDYCOLUMN experiment, we found that the size distributions were much narrower than usually assumed in radiation calculations which is in agreement with in-situ observations during this campaign. While the shape of the size distribution has only little relevance for the radiative properties of clouds, it is extremely important for understanding their formation and evolution.

Download Full-text