Naslov
A Kinetic Evaluation on NO2 Formation in the Post-flame Region of Pressurized Oxy-combustion Process
(A Kinetic Evaluation on NO2 Formation in the Post- flame Region of Pressurized Oxy-combustion Process)

Autori
Wang, Xuebin ; Dai, Gaofeng ; Yablonsky, Gregory S. ; Vujanović, Milan ; Axelbaum, Richard L.

Izvornik
Thermal science (0354-9836) 25 (2021), 4; 2609-2620

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
NO2, pressurized oxy-combustion, detailed mechanism, post-flame region

Sažetak
Pressurized oxy-combustion is a promising technology that can significantly reduce the energy penalty associated with first generation oxy-combustion for CO2 capture in coal-fired power plants. However, higher pressure enhances the production of strong acid gases, including NO2 and SO3, aggravating the corrosion threat during flue gas re-circulation. In the flame region, high temperature NOx exists mainly as NO, while conversion from NO to NO2 happened in post-flame region. In this study, the conversion of NO -> NO2 has been kinetically evaluated under representative post-flame conditions of pressurized oxy-combustion after validating the mechanism (80 species and 464 reactions), which includes nitrogen and sulfur chemistry based on GRI-MECH 3.0. The effects of residence time, temperature, pressure, major species (O-2/H2O), and minor or trace species (CO/SOx) on NO2 formation are studied. The calculation results show that when pressure is increased from 1 to 15 bar, NO2 is increased from 1 to 60 ppm, and the acid dew point increases by over 80 degrees C. Higher pressure and temperature greatly reduce the time required to reach equilibrium. With increasing pressure and decreasing temperature, O plays a much more important role than HO2 in the oxidation of NO. A higher water vapor content accelerates NO2 formation in all cases by providing more O and HO2 radicals. The addition of CO or SO2 also promotes the formation of NO2. The NO2 formation in a pressurized oxy-combustion furnace can be over 10 times that of an atmospheric air-combustion furnace.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

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