Novel rates of OH induced sulfur oxidation. Implications to the plume chemistry of jet aircraft
Somnitz, Holger; Gleitsmann, Gö tz Georg; Zellner, Reinhard
Novel rate coefficients for the most important and rate controlling sulfur oxidation reaction, OH + SO2 → HSO3, as obtained from ab initio quantum chemical/RRKM dynamical calculations over an extended range of pressure and temperature (Somnitz, 2004) have been used to calculate the rate of oxidation of S(IV) to S(VI) under typical conditions of a jet aircraft plume. From these calculations the rate of oxidation is predicted to be considerably slower than previously accepted (i.e. Tremmel and Schumann, 1999). The new kinetic results have been incorporated into a chemical-dynamical code of the jet regime of a B-747 airliner (BOAT code) to predict sulfur conversion efficiencies. It is found that the efficiency to convert sulfur in the aircraft plume is less than 1 %. It is concluded therefore that overall conversion efficiencies in the order of several % as observed experimentally, are caused by corresponding conversions in the combustor and/or turbine of the jet engine and not in the plume.