EFFECT OF MOISTURE ON NITROGEN DIOXIDE FORMATION IN LAMINAR FLAME OF NATURAL GAS

Aleksandr Sigal,Dmitri Paderno

doi:10.3846/jeelm.2021.15492

Abstract

The paper contains the results of experimental studies of the effect of moisture on nitrogen dioxide formation and on oxidation of NO to NO2 in laminar premixed flame of natural gas. The water vapor is shown to be the third very influential participant, along with fuel and oxidizer, in the combustion process. Injection of moisture into the combustion zone has an effect due to the insertion of additional quantities of HO2- and OH– radicals into the process, which contributes to the intensification of the oxidation of NO to NO2. Introduction of the concept of the “excess moisture ratio” in the combustion process is proposed. The studies were executed at the laboratory installation in conditions of formation of the V-shaped laminar flame of natural gas behind a transverse cylindrical steel stabilizer, with determining the concentrations of flue gas components.

Highlights

The valid European regulations (European Parliament & Council of the European Union, 2010, 2015) impose strict limits on nitrogen oxide emissions for fuel-burning equipment
Injection of moisture increases the proportion of nitrogen dioxide NO2 in the total content of nitrogen oxides NOx in flue gases
Decreasing of temperature with changing α both with and without injecting moisture leads to reduction of the NO formation in the flame front

Summary

Introduction

The valid European regulations (European Parliament & Council of the European Union, 2010, 2015) impose strict limits on nitrogen oxide emissions for fuel-burning equipment. One of the most common methods for reducing emissions of nitrogen oxides is ballasting the combustion zone to reduce the maximum local temperatures and, to reduce formation of the nitrogen monoxide. The recirculation gases or inert gases are most commonly used, and recently more often the water vapor is; the latter is even more effective ballast. It is necessary to take into account that moisture takes part in the combustion process, causing it to change. Injection of moisture increases the proportion of nitrogen dioxide NO2 in the total content of nitrogen oxides NOx in flue gases.

Methods

Results

Conclusion