Cf. Edwards et Pj. Goix, EFFECT OF FUEL GAS-COMPOSITION AND EXCESS AIR ON VOC EMISSIONS FROM ASMALL-SCALE, INDUSTRIAL-STYLE BURNER, Combustion science and technology, 116(1-6), 1996, pp. 375-397
Furnace-out emissions of benzene, toluene, ethylbenzene, and the xylen
es have been measured for a research-grade, industrial-style diffusion
flame burner operating under well-controlled conditions representativ
e of refinery process heaters. Flame structure was also evaluated by m
eans of visible emission imaging. Excess air was varied from 50% to su
b-stoichiometric. The fuels were methane and blends of methane, hydrog
en, and propane used to simulate the process gas burned in refineries.
Each fuel was tailored so that the inlet and boundary conditions on t
he flame were invariant between fuels-minimizing fluid mechanic differ
ences. The results show emission levels < 3 ppbv for toluene and < 0.5
ppbv for the other species under normal firing conditions. This is in
contrast to emissions from 10 to 150 ppbv observed in refinery field
tests (WSPA, 1994). They also show an increase in emissions with fuel
hydrogen and propane contents. Under sub-stoichiometric conditions, em
issions increase by orders of magnitude, with benzene replacing toluen
e as the dominant emission.