Gaseous and Particulate Emissions from Conventional Combustion and Oxy-combustion of a Lignite Coal

摘要

This manuscript reports on gaseous and particulate emissions from combustion of a lignite coal (Texas lignite PSOC 1443) in air as well as in a simulated oxy-fuel condition, i.e., in surrounding gases consisting of 40% O_2 blended with 60% CO_2. Particle sizes were in the nominal range of 53-90 μm and combustion took place in a laminar-flow drop-tube furnace, electrically-heated to a wall temperature of 1400 K. The evolution of combustion effluent gases, such as NO_x, SO_2, CO as well as particulate emissions (ashes) were monitored and compared. Chemical analysis of submicron ashes was performed. Results showed that the oxy-combustion condition altered the combustion characteristics of the coals. Therein, emissions of NO_x decreased, whereas emissions of SO_2 increased. Preliminary results showed that at the oxy-combustion condition submicron particulate ash emissions were curtailed. Moreover, chemical analysis to the submicron ash demonstrated that Si, Al, Ca, Mg, and Fe were in lower concentration at the oxyfuel condition.