Study on Parameters of Hydrogen Sulfide Treatment in Tiexin Coal Mine by Injecting Alkali

In view of the danger of hydrogen sulfide emission in Tiexin Coal Mine, coalbed methane sodium bicarbonate solution is used for treatment and according to the theoretical analysis and field test, the parameters of alkali injection in coal seams were determined, including alkali injection pressure, the quantity of alkali injection, water injection and advanced distance of alkali injection. Based on the seepage theory, the relationship between the radius affected by alkali injection and the pressure of the injection is established. The results show that the square of the radius influenced by alkali injection is proportional to the pressure of the alkali and is inversely proportional to the alkali liquid injection when the concentration of alkali and the permeability of coal seam are indicated. According to the law of conservation of the amount of chemical reaction, the amount of baking soda required to fully neutralizing the tons of coal hydrogen sulfide and the hydrogen sulfide in the injection of alkali drilling control range is determined. According to the lye mass fraction, the drilling water injection was determined. Through on-site water injection test, the study shows that the water injection of drilling is higher at the working face of 24 m to 65 m. Through on-site injection of alkali experiments, the result shows that the alkali injection in coal seam drilling is higher, up to 0.2 m³/h to 0.5 m³/h, at range of 25 m to 50 m from the working face. According to the monitoring of hydrogen sulfide emission, it can be seen that the more the drilling alkali injection is, the faster reduced of the hydrogen sulfide emission in the mining coal injected alkali is and the better the effect of hydrogen sulfide treatment is, which indicates that the determined alkali injection process parameters are feasible.