Effects of volatile–char interactions on the evolution of char structure during the gasification of Victorian brown coal in steam
MetadataShow full item record
The purpose of this study is to investigate the effects of volatile–char interactions on the evolution of char structure during the gasification of Victorian brown coal in steam. A novel one-stage fluidised-bed/fixed-bed quartz reactor was employed to carry out the experiments in the presence and absence of volatile–char interactions. The effects of thermal annealing on char structure were also investigated under similar conditions. The structural features of char were evaluated using FT-Raman spectroscopy. The results indicate that the char structural features were considerably affected by volatile–char interactions, which was shown from the Raman band area or the ratios between the band areas. H radicals from the thermal cracking/reforming of volatiles are believed to play a vital role in the changes in char structure due to the volatile–char interactions. H radicals could penetrate into char matrix and favour the condensation of aromatic rings, which was the main reason for the decrease in the ratio of small (less than 6 fused rings) to large aromatic rings during the volatile–char interactions. The volatile–char interactions also greatly affected the concentrations of O-containing groups in char and thus significantly altered the observed Raman intensity of the char.
Showing items related by title, author, creator and subject.
Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. Part IX. Effects of volatile-char interactions on char–H2O and char–O2 reactivitiesZhang, Shu; Hayashi, J.; Li, Chun-Zhu (2011)Volatile-char interactions are an important consideration in the design and operation of a gasifier. This study aims to investigate the effects of volatile-char interactions on the in situ char–steam reactivity at 800 °C ...
Effects of volatile–char interactions on in situ destruction of nascent tar during the pyrolysis and gasification of biomass. Part I. Roles of nascent charSong, Yao; Wang, Yi; Hu, Xun; Song, H.; Xiang, J.; Zhang, Lei; Zhang, S.; Min, Zhenhua; Li, Chun-Zhu (2014)This study aims to investigate the roles of char in the in situ destruction of tar during the volatile–char interactions. Rice straw and water/acid-washed rice straw samples were pyrolysed at 850 C with controlled extents ...
Importance of volatile–char interactions during the pyrolysis and gasification of low-rank fuels – A reviewLi, Chun-Zhu (2013)Volatile–char interactions are an important phenomenon in almost all existing gasification processes. The volatile–char interactions can very significantly affect almost every aspect of low-rank fuel gasification, including ...