Abstract
The kinetics of the NO–carbon reaction was studied by thermogravimetric analysis (TGA). The reactivity as a function of carbon conversion was systematically investigated through characterization of the pore structure and carbon active site evolution during reaction. Total surface area measured by CO
2 adsorption at 273
K gives a relatively constant normalized reactivity over a wide range of carbon conversions. The carbon active surface area (ASA) and unoccupied active surface area (UASA) were estimated from low-temperature NO chemisorption capacities. Large amounts of stable C–O complexes are found to form during the reaction. Results show that ASA or UASA measured in this way do not represent the reactive surface area under gasification conditions. A new kinetic model is introduced by taking into account the contributions from different carbon–oxygen surface complexes during reaction, based on the recently proposed unified kinetic scheme of Yang and coworkers.