Oxidative and immersional heating on low rank coal surfaces

Influence of Fractal Pores on the Oxidation Behavior of Brown Coal

“…Similar results were obtained for two other highrank coals, namely Millmerran and Liddell coals. 12 Previously it has been shown 5,6 that ions are able to effectively catalyze the low-temperature oxidation of low-rank coal. That this effect is largely due to cations is supported by comparing the results for untreated raw Loy Yang coal with that of Cu-treated Loy Yang coal.…”

“…3,4 In particular, DTA gives a combustion profile, or more strictly an oxidation profile, of dried low-rank coal which shows two large peaks, with features at about 300 °C which are unique to low-rank coal and another feature at around 400 °C which is common to all coals. 4,5 The lower-temperature peak is thought to be related to the tendency of coal to spontaneously combust, and recently it has been shown that this low-temperature oxidation peak is strongly affected by (a) the cation content and (b) the chemistry of the functional groups present. 5,6 Combined DTA and gas adsorption measurements have shown that the surface area has a profound effect on the high-temperature combustion of coal.…”

“…4,5 The lower-temperature peak is thought to be related to the tendency of coal to spontaneously combust, and recently it has been shown that this low-temperature oxidation peak is strongly affected by (a) the cation content and (b) the chemistry of the functional groups present. 5,6 Combined DTA and gas adsorption measurements have shown that the surface area has a profound effect on the high-temperature combustion of coal. 3,4 Recently we have shown that a useful method of characterizing the pore surfaces of brown coal is small-angle X-ray scattering (SAXS) which provides a measure of fractal geometry.…”

Water Adsorption and Desorption of Upgraded Brown Coal. Part 1: Isotherms of Adsorption and Desorption

“…The height of isotherms and the amount of heat of wetting vary according to coal rank: the lower the rank, the higher the isotherms and greater the heat of wetting. − Further, for coals of the same rank, they depend upon pretreatments, such as water leaching, acid leaching, hot water treatment, or surface oxidization …”