Preliminary Research on the Effects of Coal Devolatilization and Char Combustion Processes on the Emission of Particulate Matter during Lignite Combustion under Air and Oxy-fuel Conditions

Abstract

The pulverized coal combustion in both air and oxy-fuel conditions generally experiences successive coal devolatilization and char combustion processes. The effects of these two processes have important influence on the emission characteristics of particulate matter. With some different characteristics of lignite from the higher rank coal, including the high contents of organically bound cations and the apparent char–CO2 gasification reaction upon oxy-fuel combustion, the effects of both coal devolatilization and char combustion processes on the emission characteristics of particulate matter during oxy-fuel combustion of lignite would accordingly be distinctive. A typical Chinese lignite was devolatilized in a N2 or CO2 atmosphere to generate N2–char and CO2–char, respectively. Raw coal and the two chars were burned in a drop-tube furnace under both air and oxy-fuel conditions. Afterward, the yields and inorganic compositions of segregated PM10 were carefully analyzed. The results have shown that the devo...