Experimental Investigation of the Effect of Microstructure on Coalbed Methane Adsorption Characteristics Affected by Chemical Solvents.

Coalbed methane (CBM) reservoir modification based on chemical solvent treatment could change the coal microstructure, which further affects the adsorption capacity and flow characteristics of this clean energy. Coal samples were extracted by tetrahydrofuran (THF), carbon disulfide (CS), and hydrochloric acid (HCl). Low-pressure nitrogen adsorption, carbon dioxide adsorption, Fourier transform infrared spectroscopy, and methane isothermal adsorption test were adopted.

Preparation of Consolidated Dust Suppression Materials Based on Pectin: Graft Modification Experiment and Reaction Mechanism.

The natural material pectin was used as the matrix to prepare a dust suppressant. The regression model in response to the grafting ratio was established, and the optimum modification scheme was determined. The amount of monomer, initiator, cross-linking agent, and reaction temperature was 3.

Experimental Investigation on Bituminite Dust Suppression Characteristics of a Bonding-Wetting Composite Dust Suppressant.

In order to reduce the occupational health hazard of coal dust to miners, surface tension and viscosity tests and bituminous coal powder sedimentation experiments were conducted. A composite dust suppressant with bonding-wetting effects was developed. Meanwhile, based on the FTIR test and peak-differentiating curve fitting, the changes of peak areas of coal samples before and after dust suppressant treatment were investigated, with quantitative analysis on hydrophilic and hydrophobic groups.

Effects of Mechanical Properties on Gas-Water Flow Characteristics around Boreholes: Implementation of Damage-Based Coupling Models.

Neglecting the coal damage effect around a borehole could result in low accuracy of gas extraction seepage analysis. A fluid-solid coupling model incorporating coal stress and damage, gas diffusion, and seepage was established. Reliability of the proposed model was validated using field data.

Experimental Investigation on Pore-Fracture Variations in Coal Affected by Carbon Disulfide.

Solvent treatment is an effective technique to stimulate pore and fracture growth in low-permeability coal seams and improve the efficiency of methane extraction. Adopting the nuclear magnetic resonance test, liquid nitrogen adsorption analysis, ultrasonic test, and CT scanning, pore variation and fracture development in lignite, bituminous coal, and anthracite after carbon disulfide treatment were analyzed. Full-scale pore size distribution characteristics were obtained.

Spatiotemporal characteristics of air pollutants and their associated health risks in '2+26' cities in China during 2016-2020 heating seasons.

To understand characteristics of air pollutants and their associated health risks in recent heating seasons in China, ambient monitoring data of six air pollutants in '2 + 26' cities in Beijing-Tianjin-Hebei and its surrounding areas (known as the BTH2+26 cities) during 2016-2020 heating seasons was analyzed. Results show that daily average concentrations of PM, PM, SO, NO, and CO dropped significantly in BTH2+26 cities from the 2016-2017 heating season to 2019-2020 heating season, while 8h O increased markedly. During 2016-2020 heating seasons, annual average values of total excess risks (ER) were 2.

Effect of Sophorolipid Adsorption on the Coal Microstructure: Experimental and Wettability Mathematical Model Discussion.

Green biosurfactants are emerging as a promising area of research. However, there is a limited focus on the adsorption and wetting characteristics of biosurfactants on coal dust. This study explores the effects of sophorolipid (SL) biosurfactants on the microstructure and wettability of different coalification degree coal.

Study on pollution evolution law of coal and rock mixed dust in coal-oil shale fully mechanized mining face: a study case.

To better understand the dust dispersion and pollution laws in coal-oil shale fully mechanized mining faces, the airflow distribution and coal and oil shale mixed dust emission law was simulated, and the simulation results are analyzed and verified in combination with the field measured data. The research results showed that in the area 0-10 m on the leeward side of the front drum, most of the coal dust particles with a large particle size stay near the roof of the hydraulic support and the height of the breathing zone, while most of the oil shale dust particles with a large particle size stay in the area below the height of the breathing zone. In the height of the breathing belt, oil shale and coal dust particles seriously polluted the 0-6-m and 0-13-m areas on the leeward side of the front drum of the shearer, respectively.

Pollution and occupational protection of diesel particulate matter in underground space.

To address the diesel particulate matter pollution problem at the 12,306 continuous mining face of Shangwan coal mine, the spatial and temporal evolution law of diesel particulate matter generated at the three locations of the shuttle car head tunnel, contact alley, and support tunnel under the pressure-in ventilation condition of the double lane of the continuous mining face was studied by numerical simulation. The results show that the highest diesel particulate matter concentration at the shuttle car discharge is about 144.17 mg/m, which seriously affects the health of miners.

Research on Coal Dust Wettability Identification Based on GA-BP Model.

Aiming at the problems of the influencing factors of coal mine dust wettability not being clear and the identification process being complicated, this study proposed a coal mine dust wettability identification method based on a back propagation (BP) neural network optimized by a genetic algorithm (GA). Firstly, 13 parameters of the physical and chemical properties of coal dust, which affect the wettability of coal dust, were determined, and on this basis, the initial weight and threshold of the BP neural network were optimized by combining the parallelism and robustness of the genetic algorithm, etc., and an adaptive GA−BP model, which could reasonably identify the wettability of coal dust was constructed.

Preparation and Performance of Microencapsulated Sealing Material for Coal Mine Gas Drainage.

The performance of coal mine gas extraction borehole sealing material plays an essential role in the efficiency of gas extraction. Microcapsule technology was proposed to delay the expansion time of sealing materials to address the ineffective expansion of cement-based sealing materials in hydration. Based on conventional cement-based sealing materials, delayed-expansion microcapsules were prepared by phase separation with ethyl cellulose (EC) as the capsule wall material and montmorillonite (MMT) as the core material.

Wetting-consolidation type dust suppressant based on sugarcane bagasse as an environmental material: Preparation, characterization and dust suppression mechanism.

Coal mines generate a lot of dust during production and transportation, which not only damages the health of personnel, but also causes environmental pollution. Based on the problems of low extraction efficiency of cellulose matrix and low economy of existing dust suppressants for biomass materials, this paper uses bagasse extracted cellulose from sugar production waste as a matrix and adds polyvinyl alcohol and polyacrylamide as monomers to prepare a wetting-crusting type highly efficient environmental protection dust suppressant for coal mine production and transportation process. The dust suppression effect of the product was analyzed by the performance tests of dust suppression efficiency, consolidation layer strength and permeability.

One-Step Preparation of Activated Carbon for Coal Bed Methane Separation/Storage and Its Methane Adsorption Characteristics.

Different coals were used as raw material for the preparation of carbonization precursors and coal-based activated carbons. The physicochemical structure and adsorption performance of the samples were tested. Results show that the carbonization and activation process greatly changed the molecular structure of raw coal, and a large number of organic functional groups disappeared.

Experimental Study on Atomization Characteristics of Gas-Liquid Two-Phase Flow Nozzle and Its Dust Removal Effect.

An experimental study on the flow rate and atomization characteristics of a new gas-liquid two-phase flow nozzle was carried out to use high-concentration respirable dust in the workplace of high-efficiency sedimentation coal production based on the gas-liquid two-phase flow nozzle technology. The simulation roadway of dust fall in large coal mines was constructed, and the respirable rock dust produced by fully mechanized mining surfaces was chosen as the research object. The effects of humidity on the capture effect of respirable rock dust were analyzed in the experimental study.

Experimental Research on the Performance of a Wetting Agent Based on Compound Acidification in Low-Porosity and Hard-to-Wet Coal Seams.

To improve the wetting performance of the composite acid solution in the deep coal seam, in this paper, the surface tension and contact angle characteristics of the compound acid wetting agent are studied, then the composition of the wetting agent is developed and evaluated based on nuclear magnetic resonance. The research indicates that surfactants can reduce the surface tension of water, and the surface tension tends to decrease with the increase in the surfactant concentration. The critical micelle concentration of the anionic surfactant sodium dodecyl sulfate (SDS) solution is only 0.

Study on the Wettability of a Composite Solution Based on Surface Structures of Coal.

In order to research the influence of composite surfactant solutions on the wetting ability of coal, the wettability parameters, pore structure parameters, and surface microscopic morphology were determined in this study. The results show that the wettability of the surfactant can be improved by adding NaCl. As the concentration of NaCl increased, the spreading coefficient of the NaCl-SDS composite solution increases; the spreading coefficient increased from -10.

Effects of the linoleic acid/docosahexaenoic acid ratio and concentration inducing autophagy in Raw264.7 cells against .

Our study was to understand the autophagy induce by different ratios and concentrations of LA/DHA on Raw264.7 cell, and then to investigate the effect of Raw264.7 autophagy on the clearance of .