KINETIC MODELING OF THE H2O2 ENHANCED INCINERATION OF HEPTANE AND CHLOROBENZENE

The addition of hydrogen peroxide (H2O2) into a stream of heated air c ontaining volatile organic compounds (VOCs), such as heptane and chlor obenzene, has been found to increase the destruction of those VOCs. De tailed kinetic models for the enhanced oxidation of heptane (44 chemic al species, 144 reactions), and chlorobenzene (62 species, 212 reactio ns) were developed. The computer code CHEMKIN was used for the model s imulations, and sensitivity analyses were performed using the code SEN KIN. Additional thermodynamic data needed for the model were calculate d using the group addition methods of Benson, and the computer code TH ERM. It was concluded that the H2O2 enhancement effect in the oxidatio n of heptane occurs by the thermal dissociation of the peroxide molecu le, providing two OH radicals, followed by hydrogen abstraction of the heptane molecule by an OH radical. In the un-enhanced case the key re action is the thermal dissociation of the heptane molecule into two ra dicals. For chlorobenzene the major VOC destruction pathway seems to b e the attack of an HO2 radical to generate the phenoxy radical. The HO 2 radicals are supplied by the peroxide indirectly, through OH radical attack on other H2O2 molecules, and by other downstream reactions. Th is is a plausible explanation for the experimental observation of the need for much higher concentrations of H2O2 with chlorobenzene than wi th heptane, and for the apparent delay in the destruction of chloroben zene.