FORMATION OF NO,, PRECURSORS DURING WHEAT STRAW PYROLYSIS AND GASIFICATION WITH O_2 AND CO_2

摘要

The release behavior tests of NO_x precursors from wheat straw during pyrolysis in argon and gasification in 5%O_2/95%Ar and 5%O_2/95%Ar were performed using a thermogravimetric analyzer (TGA) coupled with a Fourier transform infrared (FTIR) spectrometer. The results show that heating rate and particle size have substantial effects on the selectivity of the N-conversion. The atmosphere influences the N-selectivity to HCN, NH_3 and HNCO. During gasification in 5%O_2/95%Ar atmosphere, a remarkable amount of biomass-N is converted into HCN, and the N-conversion to NH_3 decreases. The presence of O_2 promotes the yields of NO and HNCO evidently. In 5%CO_2/95%Ar atmosphere, the yield of HCN decreases to, about half of that in argon, the yield of NH_3 keeps essentially constant compared with that in Ar. Moreover, there is no HNCO detected during the gasification in 5%CO_2/95%Ar.