Diffusion kinetic parameters from bulk diffusion limited gas release processes

TL;DR

This paper presents an analytical method to extract diffusion kinetic parameters from gas release experiments in spherical pebbles, emphasizing the use of the time integral of the diffusion coefficient for arbitrary temperature schedules.

Contribution

It introduces highly accurate approximations for analytic expressions and a method to determine activation energy and preexponential factor ratio from a single heating ramp.

Findings

Accurate analytical expressions for bulk diffusion in spherical pebbles.

A practical method to extract kinetic parameters from single heating experiments.

Enhanced analysis of temperature-dependent diffusion processes.

Abstract

The diffusion of a bulk absorbed gas species out of spherical pebbles is studied analytically, stressing the usefulness of the time integral of the diffusion coefficient for analysis of arbitrary temperature schedule experiments. Highly accurate approximations are introduced where the numeric evaluation of the analytic expressions takes considerable time. A method is proposed to extract the diffusion kinetic parameters from a single linear heating ramp, namely, the activation energy of the diffusion coefficient and the ratio of the corresponding preexponential factor to the radius of spherical pebbles.