Yongliang Xu

Thermogravimetric Dynamics and FTIR Analysis on Oxidation Properties of Low-Rank Coal at Low and Moderate Temperatures

Oxidation properties of two coals, lignite and bituminous, at low and moderate temperatures were investigated using thermalgravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) methods. The apparent kinetic parameters were determined by the first-order Coats & Redfern method based on the TGA results. The mass developments of the two coals during the experimental temperature range of 25–400°C suggest that lignite is more prone to spontaneous combustion than bituminous coal. The kinetic analysis results show that all the absolute values of the apparent activation energies of lignite are less than that of bituminous coal, indicating that it is easier for lignite oxidation. FTIR spectra show that the structure of coals changed differently during oxidation. The aliphatic hydrogen groups (mainly the -CH3 groups), associated hydroxyls, and substituent groups in aromatic structures decreased, and carbonyl species increased in bituminous coal. For lignite, both -CH2 and -CH3 groups decreased and carbonyls increase initially and then decrease corresponding to formation of a large amount of ether bonds. The substituent-aromatic structures increase slightly in lignite.

Study of a New Kind of Green Environmental Protection Material for Fire Preventing in Coal Mines

The sand-suspending thickener (SST), which is distilled from the natural plant alga, is a kind of polysaccharide biopolymer, so the SST is poisonless, harmless and no pollution. In order to verify the characteristics of the SST, we applied the self-designed Temperature Program Experiment System to test the inhibition characteristic, and applied the small-sized and medium-sized experiment to test the suspension capability to the sand, and applied the grouting system of the pipeline to test the resistance in the pipeline of the sand-suspending grout. We found that the inhibition characteristic of the SST was excellent, the suspension capability of the SST was strong, and the SST also could decrease the abrasion and resistance for the pipeline. The results show that the SST is a new kind of excellent material for fire preventing that can meet the demand of fire preventing in the coal mines, and is worth of applying widespreadly in the coal mines.