Apparent Activation Energies for the Reduction of NO by CO and H2 over Calcined Limestone and CaO Surfaces

• Published in: Energy & fuels 1998-09, Vol.12 (5), p.945-948
• Main Authors: Acke, Filip, Strömberg, Dan
• Format: Article
• Language: English
• Subjects: Air pollution caused by fuel industries; Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuel selection. Additives; Pollution reduction
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef980024f

Apparent activation energies for the reduction of NO by CO and H2 are determined for calcined limestone and CaO surfaces. For calcined limestone, the importance of particle size on the apparent activation energy is shown. For small particle sizes, activation energies of about 20 kcal/mol are observed for both CO and H2 as the reducing agent. For coarse particles, an apparent activation energy of 32 kcal/mol is found for the reduction of NO by CO. For H2 as the reducing agent, a low-temperature value of 35 kcal/mol (550−650 °C) and a high-temperature value of 16 kcal/mol (650−800 °C) are observed. These values are compared to the apparent activation energies for the same reactions determined over three different CaO surfaces. The differences seen are ascribed to the presence of catalytically active second phases in the calcined limestone.