Reaction of Microparticles by the Diffusion of Reactive Gases through Porous Shells
Abstract
A new experimental technique, single particle electrodynamic balance (SPEB), was used to study the heterogeneous reaction between single acid droplets and basic gases. Experiments with phosphoric acid droplets and ammonia gas show that the droplet reaction dynamics are sequentially controlled by surface phase, gas phase diffusion-controlled, and porous shell diffusion- controlled reactions. Gas phase diffusion-controlled reactions terminate when ammonium phosphate crystallizes at the droplet surface, and porous shell diffusion-controlled reactions become rate limiting. We derive a semiempirical model to describe the porous shell diffusion-controlled reactions of acid droplets with surface layers of crystallized solids. The model is parameterized with an effective porous shell diffusion coefficient to describe the transport of reactive gases through the porous shell. Keywords: Heterogeneous reaction, Gas phase diffusion, Porous shell diffusion, Surface phase, Crystallization. (mjm)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1988
- Accession Number
- ADA196656
Entities
People
- Glenn O. Rubel
- James W. Gentry