The release of gaseous nitrogen compounds during pyrolysis of municipal sludge was analyzed by a combination of thermogravimetric analysis (TG) and mass spectrometry (MS) with the emphasis on lignin addition on the pyrolysis. Moreover

the dynamic change of functional groups on coke surface was detected online by Fourier-transform spectrometer (FTIR) to reveal the nitrogen migration mechanism. Results showed that NH3 came primarily from protein deamination reaction. Lignin addition produced substantial carbonyl that reacted with the amino of protein

thus promoting the generation of linear amide that would generate HCN and HNCO when attacked by OH radicals. The amino not condensed would convert to NH3 as temperature increased. Overall

40% of the lignin addition had positive effects on reducing emission of NOx precursor.