Oxidation of Sulphur Dioxide in Air at 950° C: Co-operative Influence of Carbon Monoxide and Nitric Oxide

Abstract

THE oxidation of sulphur compounds in fuel to form sulphur dioxide, and the further oxidation of a small proportion of this to sulphur trioxide, give rise to problems of atmospheric pollution and of corrosion. The severe corrosion frequently experienced in those zones of boilers where the combustion products have become relatively cool is related to the sulphur trioxide of the flue gases, and the formation of sulphur trioxide in boilers has therefore been subjected to extensive investigations. The mechanisms generally held to be responsible for the production of the greater part of the sulphur trioxide detected in boiler flue gases are: (1) oxidation of sulphur dioxide by oxygen atoms in the flame; and (2) catalytic oxidation of sulphur dioxide at surfaces in the post-flame region.