Comparative examination of aerosols of pulverized coal combustion in air and in oxygen with carbon dioxide combustion environments

The purpose of this work was to examine the effects of a change in combustion environment on aerosol formation. Due to the need to provide carbon based energy with carbon capture and sequestration to eliminate carbon emissions, oxy fuel combustion is a technology which is currently under investigation. The main advantage of oxy fuel combustion is that it utilizes a combustion process of fuel, pure oxygen, and recycled CO2 in order moderate flame temperatures. The result is a flue gas which is highly concentrated in CO2 with water vapor which is easily condensed and removed. However, there has been very little research done on the effects of the altered combustion environment from N2/O2 (air) to oxy fired conditions of O2/CO2 on aerosol formation. This work indicates that there are differences in black carbon particle emissions, as well as changes in mechanisms which drive aerosol formation. Of particular interest in the findings was that iron was found in higher relative concentrations in the submicron range of particles in oxy fired conditions compared to air fired conditions. Also, magnesium and calcium appear to be in higher relative concentrations in oxy fired conditions while sodium and potassium seem to be lower in the submicron range. These are all important as these compounds can affect how ash and slag build up on surfaces inside of the furnace.