Electric resistence hysteresis of platinum filament in chilled air/hydrogen mixtures

V V Каlіnchak,A V Fedorenko,O S Chernenko

doi:10.15330/pcss.21.3.420-425

Abstract

Ignition of gaseous combustible mixtures on catalytically active hot solid surfaces has numerous applications in many industrial processes and is a complex process that involves close interaction between surface processes and transfer processes in the gas mixture. In this paper, stable and critical states catalytic oxidation of hydrogen impurities in air on a platinum filament are considered. It is shown that filament temperature and its resistance depending on the mixture temperature and hydrogen concentration are of the hysteresis features. Within this hysteresis region, it is possible to achieve the catalytic combustion mode of hydrogen as a result preheating the catalyst filament above a certain critical value. The dependence of the limiting hydrogen's concentration on catalyst filament's diameter, above which is observed in the cold gas mixture self-sustaining catalytic combustion without electric current.

Highlights

The use of wire meshes, which is coated with a thin layer of platinum or metal oxide [1,2,3], has an advantage over powder catalysts primarily due to the ease of removing them from the reaction zone and the need for filtration
Thin metallic catalyst filament is normally applied as an initial sensor of thermochemical gas detector indicating presence of combustible gases in air/gas mixtures
Its operation is based on application of upper high-temperature regime of hysteretic relation between catalyst metallic filament temperature and combustible gas admixture concentration in air gas mixture with steady heating by electric current and air/gas flow temperature [6]

Summary

Vasyl Stefanyk Precarpathian National University

Electric Resistence Hysteresis of Platinum Filament in Cold Air/Hydrogen Mixtures. Stable and critical states catalytic oxidation of hydrogen impurities in air on a platinum filament are considered. It is shown that filament temperature and its resistance depending on the mixture temperature and hydrogen concentration are of the hysteresis features. Within this hysteresis region, it is possible to achieve the catalytic combustion mode of hydrogen as a result preheating the catalyst filament above a certain critical value. The dependence of the limiting hydrogen's concentration on catalyst filament's diameter, above which is observed in the cold gas mixture self-sustaining catalytic combustion without electric current.

Introduction

Tg T

Da g

Dg Sh g k gs

Findings

Conclusions