Study on hydrocarbon generation structure evolution of bituminous coal in Shitai Mine,Huaibei coalfield

With the process of coalification,different macerals in coal can generate oil and gas,which can be completed by thermal simulation experiment. In order to obtain the evolution characteristics of hydrocarbon generation structure of bituminous coal,the samples of No.4 coal seam in Huaibei coalfield were collected. Based on the experiment of hydrocarbon generation by gold tube pyrolysis,Fourier transform infrared spectroscopy(FTIR) and high resolution transmission electron microscopy(HRTEM),the characteristics of hydrocarbon yield under different heating rates were analyzed,the evolution law of coal chemical structure during hydrocarbon generation was studied,the structural parameters of FTIR and HRTEM were calculated,and the hydrocarbon generation mechanism was discussed The corresponding relationship between hydrocarbon yield and structural evolution. The results show that:with the increase of temperature,the yields of C1-5 and methane increase continuously,and increase sharply in the middle temperature range,C14 + first increases and then decreases,and the temperature at which the peak value is reached is different at different heating rates. CH2 / CH3 and A2800-3000 cm-1/A3000-3100 cm-1 showed different change rules,and both showed a decreasing trend. 0～0.1 nm showed the largest proportion of aromatic structure,and 0～1.0 nm showed a periodic trend of first decrease and then increase. The aromatic structures of bituminous coal and pyrolysis products mainly include 2×2,3×3,4×4,with a small amount of 5×5 aromatic structure. The main directional change of bituminous coal and pyrolysis products decreases,maintains and increases at 45°.