MUTUALLY PROMOTED THERMAL-OXIDATION OF NITRIC-OXIDE AND ORGANIC-COMPOUNDS

The mutually promoted oxidation of various organic compounds and nitric oxide in the presence of oxygen was studied in a laboratory scale flow reactor. Experiments were performed at atmospheric pressure in the temperature range 650-1300 K. The results show that in the proper temperature range a simultaneous oxidation of the organic compound and nitric oxide occurs. Nitric oxide is oxidized to nitrogen dioxide, while the combustible is converted mainly to CO. Methanol and methylamine were found to be effective oxidizers; the highest conversion was obtained with methanol, while methylamine has the widest temperature window for oxidation. Acetaldehyde, acetone, and ethane were less efficient in oxidizing NO. The efficiency of a given compound in oxidizing NO can be attributed to its oxidation mechanism as it depends on the production of peroxyl radicals, HO2. Temperature, molar ratio of the additive to NO, and reaction time were shown to be important parameters for the process performance. For a methanol/nitric oxide ratio close to 1, an oxidation efficiency of 80-90% could be obtained in a narrow temperature regime around 950 K. At lower molar ratios, the conversion of NO decreased. Very short reaction times (10-15 ms) caused the temperature window to shift to higher values while the NO oxidation potential decreased. The presence of water vapor appears to have a small beneficial impact on the oxidation efficiency. The implications of the present results for the practical application of the process are discussed.