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To improve the wettability effect of coal seam water injection, and reduce dust production from the source, this paper proposes the preparation of three kinds of high-efficiency wetting enhancers. In this study, 2-acrylamide-2-methylpropionic sulfonic acid and itaconic acid were introduced into the polymer chain of sodium alginate in different combinations. Anionic surfactant sodium dodecyl sulfate and nonionic surfactant aliphatic alcohol polyoxyethylene ether were added in different proportions to obtain three kinds of enhancers. The three kinds of enhancers have good viscosity and fluidity, and the optimal emulsifier additive is determined by a surface tension test. The hydrophilic hydroxyl, carboxyl or sulfonic groups of enhancers were obtained by a Fourier-transform infrared experiment, which was beneficial to water absorption. The contact effect of different solutions on coal block was studied by a scanning electron microscopy experiment. An energy dispersive spectrometry experiment proved that the solution was well dispersed. Through reverse osmosis experiment and contact angle analysis, the wettability of different solutions was compared, and the best enhancers was obtained. The molecular dynamics simulation was used to verify the relationship between them, and finally the mechanism of action was deduced. It was proved that AMPS-IA/SA+SDS/AEO had better wettability. Thus, AMPS-IA/SA+SDS/AEO is an ideal enhancer for coal seam water injection.

There are a lot of coal cinder and dust in the development of coal resource-based cities. Improper handling will cause dust flying, which has a great impact on urban residents and the environment. The purpose of this research is to follow the principle of waste recycling, to use waste shrimp shells to extract chitosan as a raw material, to carry out graft polymerization with acrylic acid and polyvinyl alcohol-1788, and to carry out amidation crosslinking reactions with ethylenediamine tetraacetic acid to produce products. The results showed that the degree of deacetylation of chitosan reached 85% with the optimized extraction method, which greatly shortened the process cycle. Through orthogonal experiments and osmotic wetting experiments, the best preparation process was determined. The reaction process, structure of the product and adhesive structure of the solidified layer were analyzed by FTIR, XPS and SEM. The thermal stability of the product was analyzed by thermogravimetry. Relevant performance tests showed that the product had good adhesion with dust, the hardness of the solidified layer could reach 98 HA, and the dust fixation rate was 92.67% when the wind speed was 15–18 m/s. It has the advantage of circulating dust fixation, which improves the utilization rate of resources.

Coal seam water injection fracturing can achieve the gap formation of the coal seam and increase the porosity of the coal seam. The water injection fracturing fluid wetting the coal body can wet the coal body in advance, reducing the generation of coal dust during coal mining, as well as play a preventive role in many coal mine accidents and optimize the safety state of the coal mine. To further improve the water injection efficiency of the coal seam. In this paper, erucic acid, N,N-dimethyl-1,3-propanediamine and epichlorohydrin were used as raw materials to synthesize a bisamido cationic surfactant under acidic conditions, and mixed with a KCl solution to prepare a clean fracturing fluid that can be used in the water wetting of a coal seam. The functional groups and microstructure changes of the product are observed by FTIR and SEM. Related performance experiments show that the product has the advantages of good shear stability viscosity, low filtration loss, good gel breaking performance and strong wettability. The analysis of the cleanability shows that the gel breaking liquid has a low residue content and good compatibility. Therefore, the product is an ideal clean fracturing fluid for water injection fracturing of coal seam.

In view of the inevitable microcracks and local damage of concrete materials, a new type of self-healing microcapsule material was proposed. The SA/MPF-E44 composite microcapsule material with sodium alginate/melamine phenolic resin as the shell and epoxy resin as the core was prepared by in situ polymerization. The surface morphology of the microcapsules was observed by optical microscope and scanning electron microscope. The particle size analysis was performed using a Malvern analyzer. By performing Fourier transform infrared spectrometry and a differential scanning calorimetry analysis, the functional group changes and thermal stability of the composite microcapsules were studied. The compression resistance and repair performance of cement mortar specimens with different dosage of microcapsules were tested by a uniaxial compression experiment. It can be concluded that the composite microcapsules have the characteristics of a small particle size, and the coverage rate has increased significantly. The average particle diameter is approximately 55.24 μm, and the coating ratio is 64.93%. When the microcapsule content is 4%, the microcapsule has the best compression and repair performance. The self-healing behavior of the epoxy resin and curing agent in cracks was studied by a molecular dynamics simulation. Finally, it is shown that SA/MPF composite microcapsules have certain advantages in cost and eco-efficiency, and have good self-healing ability for microcracks in concrete materials.

The incomplete and uneven dust removal of a pulse filter greatly reduces the dust removal efficiency, which affects the efficiency, service life, and running resistance of dust removers. Therefore, due to improve the pulse cleaning effect, an agglomerant developed by free radical polymerization was added during dust removal. The optimal process conditions were determined by measuring the viscosity, surface tension, and atomization effect of the agglomerant solution. The phases, chemical composition, surface morphology, and morphology of the agglomerant and coal dust were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. Molecular dynamics simulations were used to study the interaction mechanism between the agglomerant and coal dust. Finally, the dust removal performance under water mist conditions and agglomerate solution atomization was tested using a pulse filter. The results showed that a 0.3 % agglomerant solution effectively reduced the surface tension of the solution and displayed good wetting and bonding properties. Compared with water misting, the agglomerant solution subjected to an atomization rate of 2400 m3/h prolonged the filtration period, reduced the filtration resistance, and reduced the dust emission concentration. These results have important theoretical and practical significance for improving the dust removal effect of pulse filters.