Construction of molecular structure and active site analysis of Zichang coking coal: experimental and computational study.

In the study, the structural parameters of Zichang (ZC) coking coal from northern Shaanxi Province were examined. A theoretical calculation was employed to build a molecular structure model for ZC coal, as well as applying principles of quantum chemistry, the prediction of NMR spectrogram and density for the model was achieved, and the molecular chemical formula was C199H155O36N3. The molecular structure optimization and annealing kinetics calculations are based on molecular mechanics (MM) and molecular dynamics (MD). Subsequently, a representative simplified model was constructed using the aromatic structure as the fundamental unit. On this foundation, the electrostatic potential (ESP), atomic charge distribution, and energy level orbitals were analyzed for this simplified model. The outcomes of this research can serve as an essential guide for determining the reaction order of the active categories during the low-temperature oxidation process for ZC coking coal.

Preparation and Characterization of a Composite Dust Suppressant for Coal Mines.

In an effort to effectively control coal dust pollution and thereby reduce the harm of coal dust to human health, we prepared a highly efficient composite dust suppressant. First, dynamic contact angle and zeta potential measurements were used to select sodium dodecyl sulfonate (SDS) over sodium carboxymethyl cellulose and trisodium methyl silicon as the complementary additive to soy protein isolate for the dust suppressant. We employed viscosity and wind erosion resistance tests to compare the performance of the composite dust suppressant with three common, commercially available suppressants. As the concentration of the composite dust suppressant was increased, the viscosity increased, reaching a maximum value of 22.7 mPa·s at a concentration of 5 wt%. The 5 wt% concentration of the composite dust suppressant provided the lowest wind erosion rate (20.62%) at a wind speed of 12 m/s. The composite dust suppressant also had good bonding performance and wind erosion resistance. Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were used to characterize the properties of the dust suppressants. The dust suppressant, which had a crystal-like structure, could easily capture coal dust and form an effective package. In addition, the density of the dust suppressant film increased as its crystallinity increased. The increased density was beneficial in that it enabled the dust suppressant to form a hard, solidified shell on the surface of coal dust, which improved dust suppression. The composite dust suppressant also had good thermal stability.