AIRCRAFT EXHAUST SULFUR EMISSIONS

The conversion of fuel sulfur to S(VI) (SO3 + H2SO4) in supersonic and subsonic aircraft engines is estimated numerically. Model results ind icate between 2% and 10% of the fuel sulfur is emitted as S(VI). It is also shown that, for a high sulfur mass loading, conversion in the tu rbine is kinetically limited by the level of atomic oxygen. This resul ts in a higher oxidation efficiency at lower sulfur loadings. SO3 is t he primary S(VI) oxidation product and calculated H2SO4 emission level s were less than 1% of the total fuel sulfur. This source of S(VI) can exceed the S(VI) source due to gas phase oxidation in the exhaust wak e.