TG-FTIR analysis of nitrogen conversion during straw pyrolysis: A model compound study

2,5-diketopiperazine (DKP) was selected as N-containing model compound to investigate fuel-N conversion pathway during straw pyrolysis. The experiments were conducted using a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer (TG-FTIR) in argon atmosphere. The results show that NH3, HCN and HNCO are the major N-containing species during DKPs pyrolysis at 20, 40 and 60°C/min. The yield of NH3 is the largest, followed by HCN and the amount of HNCO is the lowest. With increase of heating rate the weight loss curve moves to right and the yield of HNCO and HCN increases, while that of NH3 decreases. K, Ca and Fe have a catalytic effect on nitrogen conversion during DKPs pyrolysis. In the presence of K and Ca, the formation of NH3 and HCN is enhanced. Fe can promote the formation of NH3, but inhibit that of HCN.