The estimation of char reactivity from coal reflectogram

Measurements of the intrinsic reactivity of chars to oxygen are increasingly being sought as an indicator of the combustion potential of fuels. The coal reflectogram has been used to characterize the chemical properties of coal and its resultant char structure. In this study, six Australian coals varying in rank were separated using density separation technique to obtain vitrinite and inertinite rich fractions. Chars were obtained from these density fraction samples in a Drop Tube Furnace (DTF) at 1673 K. The reactivity of the chars was measured non-isothermally in a Thermal Gravimetric Analysis (TGA) in the temperature range of 573-1073 K. The results suggested that with the increase in the coal rank, the maximum reactivity of chars derived from vitrinite rich fractions decreases, while the reactivity of chars derived from inertinite rich fractions decreases with the increase in the inertinite content in samples and has no obvious relationship with rank. The kinetic parameters were derived using data from non-isothermal TGA after accounting for changing in surface area with conversion. The frequency factor is found to decrease with increasing coal FMR, defined as the summation of each reflectance value multiplied by its frequency, for a constant activation energy (E = 146 kJ/mol). This suggests that the behavior of a maceral is characterized primarily by its reflectance distribution instead of the type of its parent coal

过氧化氢水溶液作用下甲烷水合物分解特性的分子动力学模拟研究

In this work, the characteristics of the decomposition of methane hydrate Structure I (SI) in the presence of hydrogen peroxide solution is investigated using the molecular dynamics simulation. The mechanism of the transformation process from the solid hydrate to the liquid is analyzed with the effect of hydrogen peroxide (HP) solution. In addition, the effect of ethylene glycol (EG) with the same molar concentration with HP on the methane hydrate dissociation is also studied. The results illustrate that both HP and EG promote well the hydrate dissociation. The work provides the important reference value for the experimental investigation into the promotion effect of HP on the hydrate dissociation

Molecular Dynamics Simulation on Characteristics of Decomposition of Methane Hydrate in the Presence of Hydrogen Peroxide Solution

In this work, the characteristics of the decomposition of methane hydrate Structure I (SI) in the presence of hydrogen peroxide solution is investigated using the molecular dynamics simulation. The mechanism of the transformation process from the solid hydrate to the liquid is analyzed with the effect of hydrogen peroxide (HP) solution. In addition, the effect of ethylene glycol (EG) with the same molar concentration with HP on the methane hydrate dissociation is also studied. The results illustrate that both HP and EG promote well the hydrate dissociation. The work provides the important reference value for the experimental investigation into the promotion effect of HP on the hydrate dissociation