Triboplasma assisted chemical conversion in granular systems: a semi-analytic model

TL;DR

This paper introduces a semi-analytic model for plasma-assisted chemical conversion in granular systems, highlighting the role of triboplasmas generated in granular flows and their potential in chemical synthesis processes.

Contribution

The work extends triboelectric charge relaxation theory to include plasma energy and particle balance, enabling prediction of reactive species formation in triboplasma systems.

Findings

High excited nitrogen species densities comparable to existing plasma pathways.

Regime diagram for triboplasma formation based on Paschen breakdown parameters.

Particle velocity, radius, and space charge significantly influence plasma densities.

Abstract

We present a semi-analytic model for a novel plasma-assisted chemical conversion pathway using triboplasmas generated in granular flows. Triboelectric charge relaxation is a well known phenomena where the potential generated from contact charging of particles exceeds the breakdown voltage of the background gas. In this work, we extend the triboelectric charge relaxation theory to include non equilibrium plasma energy and particle balance equations to predict the formation of dissociated and excited species that act as precursors to chemical conversion, for example in plasma-assisted ammonia synthesis. Our example case study with nitrogen background gas and teflon/aluminum tribomaterial system yielded high excited nitrogen species densities per collision that are comparable to current plasma-assisted conversion pathways. We also present a regime diagram for various gases where Paschen breakdown parameters are used to determine whether triboplasmas can be formed for a given effective work-function difference between two materials. Our sensitivity studies indicate particle velocity, particle radius, solids fraction and space charge effects play a critical role in overall plasma densities and excited species production.