Effect of a high-density coarse-particle layer on the stability of a gas–solid fluidized bed for dry coal beneficiation

HRTEM Analysis of the Influence of Non-stick Coal's Oxidation Degree on Aromatic Fringe Morphology

The purpose of this research was to explore the parameters of the aromatics lattice fringes by using high resolution transmission electron microscopy (HRTEM) patterns, combined with ArcGIS and MATLAB methods, to quantitatively evaluate and analyze the coal samples oxidized by different concentrations of H₂O₂, and to explore the changes in the morphology and spatial distribution of the aromatic system under oxidation. As the degree of oxidation increased, the orientation of the aromatic lattice fringes became more disordered, and the distortion degree increased. The distribution range of Y and T type dislocation structures, which were widely distributed in short (<0.59 nm) lattice fringes, increased, while that of spiral type dislocation structures, which were distributed in medium (0.59-0.99 nm) and long (1.00-2.49 nm) lattice fringes, decreased. In addition, the collapse and condensation of aromatic slices caused by continuous oxidation further weakened the π-π stacking effect between aromatic rings, resulting in a decrease in the interlayer distance and stacking height. The advantages of HRTEM analysis were confirmed by XRD, SEM and FTIR analysis. This provides a new perspective on the oxidation phenomenon and enriches the examination of the low-temperature oxidation mechanism of coal.

The Effect of the Characteristics of the Partition Plate Unit on the Separating Process of −6 mm Fine Coal in the Compound Dry Separator

Although compound dry separation technology has been applied to industrial applications for +6 mm size fraction of coal separation, the technology has not been widely applied in the separation of fine coal (−6 mm). In this study, the effect of the partition plate unit characteristics on both the average density of particles in the bed uniformly and the final separation results in a fine coal separation process were studied. According to the results, the standard deviations of the corresponding density distribution were 0.08, 0.14, and 0.07 when the height of the partition plate was 2.5 cm, the partition plate angle was 35°, and the distance from the apex of partition plate on the backplane, was 12 cm, respectively, which were the lowest values at the same level. These results showed that the average density of particles in the bed was uniformly, and its corresponding density distribution contour map was more regular. When the amplitude was 2.8 mm, the frequency was 29 Hz, the height of the partition plate was 2.5 cm, the partition plate angle was 35°, and the distance from the apex of the partition plate to the backplane was 12 cm; as a result, the E value was 0.115 g/cm3, the yield of the concentrate was 69.24%, the ash content was 12.52%, and the separation effect was better. The characteristics of the partition plate unit have an important effect on the separating process of −6 mm fine coal in the compound dry separator.

Clean Desulphurization of High-Sulfur Coal Based on Synergy Effect between Microwave Pretreatment and Magnetic Separation

Coal is the world's second largest energy resource and the primary energy resource in China. Coal-fired power generation is the dominant source for obtaining power both in China and the world. This situation is considered to remain unchanged for the coming few decades. The paper is to study the mechanism of microwave absorption capacity of the magnetic medium. A mechanism for the microwave energy absorption of fine coal is proposed by obtaining the parameters of dielectric properties of the magnetic medium. The prediction model of electromagnetic parameters during the process of microwave dielectric enhancement of fine coal is established by using the neural network method. The content of magnetic medium, by increasing the electromagnetic parameters to improve the energy utilization rate and reduce energy loss, can effectively improve the absorption and broaden bandwidth of the coal sample, improving the frequency adaptive design of coal by the microwave pretreatment process. A neural network model for the prediction of the electromagnetic parameters of fine coal is established by using the neural network method. The desulfurization rates were 23.99 and 45.78% for Weinan and Lu'an coals, respectively.