Effects of CO2 on the fuel nitrogen conversion during coal rapid pyrolysis

To investigate the fuel nitrogen conversion during rapid pyrolysis, the tests with Genesee bituminous coal and Petroleum coke were accomplished under N2 and CO2 atmosphere in a fixed bed reactor equipped with a Fourier transform infrared analyzer. The samples were analyzed by an X-ray photoelectron spectroscopy (XPS) to determine the fuel nitrogen conversion mechanism during rapid pyrolysis. Furthermore, the fuel nitrogen distribution in pyrolysis products were also calculated based on the testing results. It was found that higher temperature can enhance the conversion of fuel nitrogen in the char to both HCN and NH3. The effects of CO2 on coal pyrolysis depended heavily on the temperature of rapid pyrolysis. There were more quaternary nitrogen (N-Q) consumed during rapid pyrolysis in CO2 atmosphere than that in N2 atmosphere, causing more NH3 formation in CO2 atmosphere. Higher temperature can restrain the formation of N2 as a result of the generation of more H free radicals. Besides, NO was also one of the major products during coal rapid pyrolysis.