Evaluation on nitrogen conversion during biomass torrefaction and its blend co-combustion with coal.

In this work, biomass torrefaction was combined with coal co-combustion to illustrate the differences in biomass performance and the mechanisms of migration and transformation of nitrogen over the entire course of thermal treatments. XPS analysis illustrated that torrefaction in CO2 suppressed the conversion of pyrrole-N (N-5) to quaternary-N (N-Q), whereas the trend for an O2 atmosphere moved in the opposite direction. During co-combustion, the impact on NO emission reduction shifted from positive to negative as the pretreatment temperature was raised, which is closely related to the six elementary reactions involving the intermediacy of NCO and NH, as well as to heterogeneous reduction of NO with char. In addition, torrefaction in a N2/O2 atmosphere at a lower temperature of 250 °C improved the properties of biomass and achieved the lowest NO emission during co-combustion, which provides the supporting theory needed for using effluent in power plants as a torrefaction medium.

A new FTIR method for estimating the firing temperature of ceramic bronze-casting moulds from early China.

Intricate ceramic bronze-casting moulds are among the most significant archaeological remains found at Bronze Age metallurgical workshops in China. Firing temperature was presumably one of the most important technical factors in mould making. However, it has proven difficult to determine the firing temperatures of excavated moulds using existing analytical methods. This study establishes an innovative new method for using Fourier-transform infrared spectroscopy (FTIR) to estimate the firing temperature of clay-containing remains. The method is based on the finding that the infrared absorptivity of fired clay minerals, measured at the Si-O-Si stretching resonance band, is negatively correlated with firing temperature. Moulds and mould cores dating to the Early Shang period (sixteenth to fourteenth century BCE) are found to have been fired at extremely low temperatures-as low as 200-300 °C in many instances. These results provide critical new data for understanding the metallurgical technology of ancient China.