Oxygen combustion (or oxy-fuel combustion) technique has been proposed to reduce CO₂ emission from large scale industrial thermal plants as one of the perspective combustion technologies. Use of O2/CO₂ mixture as an oxidizer in the combustion process is proposed for efficient CO₂ capture and sequestration, since CO₂ capture is more easily achieved from concentrated CO₂ stream. Besides this, absence of nitrogen in reactants enables zero emission of nitrogen oxides and is particularly attractive for combustors operated at elevated pressures such as gas turbine combustors. It is because the allowable emission level of the nitrogen oxides often determines the overall combustor efficiency through limiting the highest possible operating pressure. This leads to the further requirements of fundamental studies on the oxygen combustion, that is, combustion with a large amount of CO₂ and no nitrogen in the reactants at elevated pressures.

Here, we investigated characteristics of combustion with concentrated CO₂ and no nitrogen in the reactants at elevated pressures as a fundamental of the future applications of the oxygen combustion for gas turbine combustors. The effects of high concentration of CO₂ in the reactants on extinction characteristics were examined for the stable and safe operations of combustors.

Flame image of oxyfuel combustion
at elevated pressure

Experimental apparatus