Heat and mass transfer at sublimation of a single chromium (III) and zirconium (IV) β-diketonate particle in the inert gas mixture

Igor Igumenov,Sofya Makarova,Maksim Makarov,S.V Alekseenko

doi:10.1051/matecconf/201711508001

Abstract

The paper proposes a physical and mathematical model of nonstationary sublimation of single spherical particles of volatile chromium (III) and zirconium (IV) β-diketonates, floating in the flow of a binary helium-argon mixture. The influence of the carrier gas composition on the kinetics of sublimation has been analyzed. The addition of helium to the carrier gas is shown to increase the intensity of sublimation.

Highlights

Heat and mass transfer at sublimation of solid particles is important for optimizing the operation modes of cryogenic systems, for intensifying the low-temperature drying of pharmaceuticals and food products, as well as in the development of new technologies of chemical vapor deposition (CVD)
This paper presents the physical and mathematical model of sublimation of a single particle of the metalorganic compound, floating in a binary mixture of inert gases
At a high concentration of argon in the environment ( KeAr 0.95 ) the vapor-gas mixture at the phase change boundary is more enriched in helium, and at low concentration it is the other way around

Summary

Introduction

Heat and mass transfer at sublimation of solid particles is important for optimizing the operation modes of cryogenic systems, for intensifying the low-temperature drying of pharmaceuticals and food products, as well as in the development of new technologies of chemical vapor deposition (CVD). A method of chemical deposition from the gas phase using volatile compounds of metals with organic ligands (MO CVD) is promising for obtaining such coatings [1, 2]. The necessary high concentration of precursor in the vapor phase can be achieved through sublimation under the conditions of intensive heat and mass transfer. High intensity of heat supply to the surface of particles suspended in an inert carrier gas may be obtained in a centrifugal fluidized bed of large inert particles in the vortex chamber [3]. For the optimum design of the vortex chamber the essential is the kinetics of substance sublimation, depending on the thermodynamic and transport properties of the precursor and carrier gas

Methods

Results

Conclusion