Multi-fractal characteristics of pore structure for coal during the refined upgrading degassing temperatures

Abstract The low-temperature nitrogen adsorption measurement is commonly used to describe the pore structure of porous medium, while role degassing temperature in does not attract enough attention, various temperatures may lead different characterization for same coal. In this study, low-rank coal collected from Binchang mining area, southwest Ordos Basin was launched under seven (120 °C, 150 180 210 240 270 °C and 300 °C), respectively, dynamic change refined upgrading are studied, it also quantitative evaluated with multi-fractal theory. results show that specific surface area volume decrease linearly increased temperatures, ranges 12.53 2.16 m 2 /g 0.01539 0.00535 cm 3 /g, respectively. While average aperture features contrary characteristics (various 4.9151 9.9159 nm), indicating has been changed during temperatures. With sizes hysteresis loop decrease, connectivity enhanced. dimension spectrum could better present partial abnormal quality index, D q spectrum, −10 – 10 homogeneity pores finely. selected as three knee points, which can reflect Under lower (< feature a certain increase, following presents stable when °C. would further enhanced until reaches Because melting exceeds complexity increased. we advise should exceed 120