Transformation mechanism of C and N during rapid devolatilization of pulverized coal particles under the pressurized atmospheres

Abstract

Pressurized O2/CO2 combustion technology is a new power generation technology that can achieve CO2 capture efficiently. In this study, we investigated the pressurized devolatilization of Shenhua bituminous coal in a pressurized drop tube furnace experimental system at 1273 K. The evolution mechanism of carbon/nitrogen gas–solid products during the pressurized devolatilization process was analyzed using online measurements and offline analysis. We found that increasing the pressure from 0.3 to 1.2 MPa promoted the emission of CO and inhibited emission of NO. N2O emissions were insensitive to the change of pressure, and NO2 emissions were almost zero under the experimental conditions. The introduction of CO2 decreased the production of NOx and primary sources of nitrogen-containing gas-phase products were N-5 and N-6 active groups. Therefore, pressurized O2/CO2 combustion technology can effectively reduce NOx emissions in the devolatilization of pulverized coal and impact the subsequent char-combustion process.