Review:Resuspension of wall deposits in spray dryers

Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product contamination risk and a fire or explosion risk when spray drying products that oxidize exothermically, such as milk powder. Re-entrainment is the resuspension of spray dryer wall deposits into the main gas stream for collection as product. Literature suggests that the process for re-entrainment of particles from spray dryer wall deposits is strongly dependent on particle size and gas velocity.     

Prediction of wall deposition behaviour in a pilot-scale spray dryer using deposition correlations for pipe flows

INTRODUCTION Abbott (1990) reported that wall deposition inspray dryers may pose a potential fire risk and com-promise hygiene requirements, and reduce productquality and yield. Spray dryer hazards include igni-tion of explosible dust clouds, dust deposits, bulkpowder deposits and flammable vapour. Kieviet(1997) noted that wall deposition affected the resi-dence time distribution of particles, and particularlythat an important factor in determining residencetimes with high wall deposition…     

Multidimensional modeling of Dimethyl Ether （DME） spray combustion in DI diesel engine

INTRODUCTION The use of dimethyl ether (DME) as an alterna-tive fuel appears to be a promising approach for si-multaneously minimizing NOx and soot emissionfrom conventional diesel engines. The lowself-ignition temperature of 508 K and the high oxy-gen content of 34.8 percent (mass fraction) are twomajor factors characterizing low soot and unburnedtotal hydrocarbon (THC) emissions. Since the firstintroduction of the concept by Sorenson and Mik-kelsen (19…     

Semi-analytical Monte Carlo simulation of laser-induced fluorescence propagation in an optically participating spray

A semi-analytical Monte Carlo (SMC) simulation was developed to simulate the propagation of laser-induced fluo- rescence (LIF) in an optically participating spray, which simultaneously exhibits spectrally dependent emission, anisotropic scattering, absorption, and re-emission. The SMC simulation is described and then applied to an experimental configuration of a cloud of polydisperse droplets composed of water and sulforhodamine B dye. In the SMC simulation, the collected LIF flux on the remote receptor element is calculated as the global contribution from the emissive source, single, twice, … and nth collision events in any sequence. The effects on the fluorescence photons propagation of spray parameters like the dye concentration, droplets concentration, and droplets size are examined. Three spectral bands representing different optical properties are chosen to analyze the interference of absorption, scattering and re-emission on the detected LIF flux. The obtained spectral LIF flux distribution on the receptor demonstrates a “red shift” phenomenon.     

Morphology and Structure Analyses of SnO2 Thin Film Coated on Al2O3 Ultrafine Particles by Gas Phase Reaction in Fluidized Bed

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