Application of 13c-nmr coal structure analysis for the formation of volatile from high-volatile coals under high-temperature pressurized gasifier conditions

Understanding the relationship between volatile matter evolution behavior and chemical structure of coal is important to clarify the reactions in the coal gasification furnace. However, the relationship between 13C-NMR data of coal, the structural parameters of coal based on the chemical percolation degradation (CPD) theory, and the decomposition behavior of coal observed in the high-pressure flow-tube reactor (high pressure DTF) is not fully clarified. In this study, coals with fuel ratios of 0.94 and 1.64 were analyzed by 13C-NMR, then the volatile evolution data was obtained using a high pressure DTF at a temperature range from 800°C to 1200°C with residence time from 0.4 s to 0.8 s. By setting the chemical shift peak of bridgehead carbon at 133 ppm and 131 ppm respectively, the calculation results based on the CPD theory agreed with the volatile evolution behavior obtained by the high-pressure DTF experiments. The difference in the chemical shift peak between two coals was attributed to difference in the number of carbon rings constituting the aromatic cluster.