Effects of O2 enrichment and CO2 dilution on laminar methane flames

This study presents the effects of O-2 enrichment and CO2 (carbon dioxide) dilution on laminar methane flames. For that purpose, the following procedure was followed: i) measurements of laminar methane flame velocities carried out in a stainless steel combustion chamber at atmospheric pressure and 300 K; ii) calculations and comparison with experiments of laminar flame velocities to validate the reaction mechanism; and iii) simulations in larger ranges of flames conditions near to gas turbine conditions: premixed methane-air flames, preheated inlet temperature (To = 600 K) and pressures ranging from 1 to 8 bar. Lean, stoichiometric and slightly rich conditions were studied as the equivalence ratio was varied from 0.7 to 1.1. Both influences of the oxygen enrichment and CO2 dilution are discussed. Finally, a feasibility study of the coupling of oxygen-enriched combustion in gas turbines and CO2 capture by membrane processes, which requires high CO2 concentration in the flue gas, was carried out. A large numerical database of combustion conditions was obtained, among which the optimal initial combustion conditions allowing a correct operation of the entire process could be chosen. (C) 2013 Elsevier Ltd. All rights reserved.