Controls on Hydrogen Sulfide Formation and Techniques for Its Treatment in the Binchang Xiaozhuang Coal Mine, China

Abstract

To determine the main factors controlling hydrogen sulfide enrichment in coal mines, the #4 coal seam in the Binchang Xiaozhuang coal mine, China, was investigated. A new hydrogen sulfide control method was also tested on this seam. Using coal petrography, X-ray diffraction, and other techniques, the reactions that generated hydrogen sulfide in the Xiaozhuang coal were investigated. The main controlling factors that affect the physical and chemical properties of coal and its H2S are analyzed from the perspectives of thermal evolution temperature, gas adsorption, pore characteristics, total sulfur content, and the coal’s reducibility index. In addition, the degree of correlation for each factor was determined quantitatively using the gray system theory to construct a generalized gray relational degree evaluation model. Finally, a high-pressure circulating pulsed alkali treatment technique was proposed to cope with the dangerous levels of hydrogen sulfide found in coal mines. The treatment technique was applied in the field. The results of the investigation on hydrogen sulfide formation show that H2S in the #4 coal seam was generated by biological sulfate reduction. When the concentration of hydrogen sulfide increased from 0.8 to 6 ppm, the ranges of the thermal evolution temperature, the adsorption constant, the Brunauer–Emmett–Teller (BET) specific surface area, the total sulfur content, and the reducibility index increased from 96 to 113 °C, 28.8 to 36.2, 0.4125 to 0.9864 m2·g–1, 0.21 to 0.88%, and 3.1 to 8.5, respectively. The correlation coefficients of the main controlling factors, in a descending order, were as follows: reducibility index > adsorption constant > total sulfur content > thermal evolution temperature > BET specific surface area. The high-pressure circulating pulsed alkali treatment method tested can effectively control the high concentrations of hydrogen sulfide and prevent hydrogen sulfide-related mine shutdowns.

Experimental Study on Strengthening and Sealing Materials and Their Application in Coal Mines

“…A large amount of gas is often associated with a coal seam and is a valuable source of clean energy, and at the same time, it can threaten the safety of mine operation [1][2][3][4]. With the continuous increase of coal mining depth in China, gas disasters are becoming more prominent [5][6][7][8].…”