In-situ decoupling effect of H2O on the whole process of coal gasification in MFBRA and TG-FTIR-MS

Publication date: Available online 27 November 2019Source: Journal of Analytical and Applied PyrolysisAuthor(s): Dongdong Feng, Dawei Guo, Yijun Zhao, Yu Zhang, Kai Geng, Guozhang Chang, Shaozeng SunAbstractO2/H2O oxy-fuel combustion, as one of the most promising combustion technologies for CO2 reduction, has become a hot spot around the world. In oxyfuel combustion, H2O gasification has an important effect on the overall reaction process. This paper used Chinese Shenhua coal as raw material to decouple the effect of H2O on the whole process of raw coal-H2O gasification reaction. At 800 °C in 15 vol.% H2O, the changes of gas-liquid-solid phase product concentration and the development of char structure in the coal-H2O gasification were investigated. The MFBRA was used to analyze the rapid coal-H2O gasification reaction, while the slow-heating-rate gasification of coal was analyzed by TG-FTIR-MS. The results show that in the rapid single-particle reaction at 800 °C, H2O promotes the whole devolatilization of coal, with a certain inhibitory effect on the secondary gas-phase reaction, especially for the H2 release. H2O increases the oxygen-containing functional groups on the char surface and increases the structural defects in char. H2O would increase the -COO- groups, and promotes the consumption of C = C on the surface. H2O has an obvious etching effect on the char surface. For slow-heating-rate gasification of coal, the reaction has obvious secondary weightlessness,...

Source: Journal of Analytical and Applied Pyrolysis - November 29, 2019 Category: Chemistry Source Type: research