The effect of steam addition on sulphur trioxide formation during the combustion of liquid fuels

A study of the kinetics of SO₃ formation has been undertaken in a liquid fuel fired, non-catalytic quartz tube combuster. The effects of excess air, residence time, gas temperature, and steam injection on the level of SO₃produced have been investigated.
A non-catalytic quartz tube combuster was built with the
required safety precautions. Provisions for maintaining near
isothermal conditions along the tube and also injecting steam
into the combustion chamberweremade. An electrically heated
temperature controlled chamber evaporated the fuel which was
mixed with air and passed through a stainless steel sintered
disc and a flat flame was produced just outside the disc.
A kinetic study of SO₃ formation was done with a laminar flame and it was found (a) the excess air, (b) the residence time, (c) the gas temperature all had effects on the formation of SO₃in the fluegases. Sulphur trioxide concentration was
determined by a chemical wet method.
The effect of steam injection on the formation of Sulphur
trioxide was investigated and shown that steam injection in the flame could provide a method of reducing SO₃ and hence a reduction of corrosion. The maximum amount of SO₃ reduction was found to be about 14% when steam was injected at 17.5 mm from the origin of the flame.