Synergistic SOx/NOx chemistry leading to enhanced SO3 and NO2 formation during pressurized oxy-combustion

• Published in: Reaction kinetics, mechanisms and catalysis mechanisms and catalysis, 2018-04, Vol.123 (2), p.313-322
• Main Authors: Wang, Xuebin, Adeosun, Adewale, Yablonsky, Grigory, Gopan, Akshay, Du, Pan, Axelbaum, Richard L.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Physical Chemistry
• ISSN: 1878-5190; 1878-5204
• DOI: 10.1007/s11144-017-1327-3

Pressurized oxy-combustion is a promising technology that can significantly reduce the energy penalty for CO 2 capture in coal-fired power plants. However, higher pressure might enhance the production of strong acid gases, including SO 3 and NO 2 , which will lead to higher rates of corrosion. In this study, we investigated a reduced but combined SO x and NO x mechanisms and the synergistic formation of SO 3 and NO 2 was kinetically evaluated under different pressures and temperatures up to 15 atm and 1100 °C. The calculation results show that the interaction of SO x and NO x significantly accelerates the conversion rates of SO 2 to SO 3 and NO to NO 2 , and the acceleration is much stronger at elevated pressures and comparatively low temperatures. With a strong interaction between SO x and NO x due to elevated pressures, the formation pathways of SO 3 and NO 2 through HOSO 2  + O 2  = HO 2  + SO 3 and HO 2  + O = NO 2  + OH, respectively, are dramatically promoted. These two reactions are linked by the reaction SO 2  + OH + M = HOSO 2  + M, resulting in a ‘strong’ cycle, which can be represented by the global reaction NO + SO 2  + O 2  = NO 2  + SO 3 . This cycle is the major route for the formation and destruction of both SO 3 and NO 2 at elevated pressures.