Drying kinetics of lignite, subbituminous coals, and high-volatile bituminous coals

Mathematical modelling of Collie coal pyrolysis considering the effect of steam produced in situ from coal inherent moisture and pyrolytic water

“…One approach is assuming drying to be an additional chemical reaction described by an 1st-order Arrhenius expression [9,[15][16][17]. This is adopted here as an empirical approach, due to its good integratability into the present model and it reasonably models moisture evaporation in fuel particles [9,[15][16][17]. The kinetic parameters are fitted from drying experiments on Collie coal pf-sized particles using a thermogravimetric analyser (TGA) at various heating rates.…”

Thermogravimetric study and modeling for the drying of a Chinese lignite

“…Critical moisture content is defined as the value after which the drying rate shifts from constant rate to the falling rate period. It refers to the transition that the surface film of moisture had been reduced by evaporation to such an extent that further drying of coal causes dry spots to appear on the coal surface . The activation energy for water liberation at the second stage of coal drying is from the interaction between water molecules and the specific sites in the coal structure .…”

Effects of particle size on the desorption kinetics of water from Beulah-Zap lignite coal: Differential scanning calorimetry results

“…In Equation (9) the first term on the right hand side depicts the unimolecular decay, while the second term represents 2nd-order diffusion kinetics. 1)for three particle sized lignite coal were determined and listed in Table 2.…”

“…3 Graphs compare the experimentally observed desorption kinetics data with the calculated values of Equation (9) for three sized particles, i.e., (A) < 841 pm, (B) < 106 pm, and (C) < 37 pm. a(T) values were normalized so that C, + C, = 1 for each particle size.…”