17 / 2023-05-14 04:03:23

Inhibition effect of bituminous coal dust explosion by NaHCO3

bituminous coal explosion,explosion inhibition,explosion pressure,explosion inhibition model

Bituminous coal exhibits excellent combustion characteristics and finds widespread applications in energy production, industrial fuel, metallurgy, and chemical industries. However, in fields such as metallurgy and chemical industry, the suspension of bituminous coal dust can easily lead to explosions when encountering high-temperature heat sources, posing significant threats to safety. Therefore, it is imperative to conduct research on explosion inhibition of bituminous coal dust.

Chemical inhibitors and gas suppressants are commonly employed methods to mitigate the explosion hazards of coal dust. Chemical inhibitors interact with the surface of coal dust particles, forming a protective film to reduce their self-ignition and explosiveness. Gas suppressants, predominantly inert gases, dilute the mixture of coal dust and air, lowering the oxygen concentration to inhibit coal dust explosions. However, the use of gas suppressants in mining environments carries the risk of asphyxiation and entails higher costs, leading to the preference for chemical inhibitors as a practical approach to coal dust inhibition. Some commonly used chemical inhibitors include NaHCO₃, NH₄H₂PO₄, and NaCl.

In order to enhance the targeted explosion inhibition of bituminous coal dust and achieve precise control, this study investigates the inhibitory effect of NaHCO₃ as a chemical explosion inhibitor on bituminous coal dust under different particle sizes and concentrations. Furthermore, explosion inhibition experiments are conducted using a 20L spherical explosion test apparatus, and the evolution process of bituminous coal dust explosion hazards is analyzed. Based on a wealth of experimental data, a mathematical model is established to determine the required concentration of explosion inhibitors for suppressing bituminous coal dust explosions (Figure 1).

The results demonstrate that the maximum explosion pressure and rate of pressure rise of bituminous coal dust occur at a concentration of 1000 g/m³, reaching 0.66 MPa and 37.85 MPa/s, respectively. With increasing particle size and concentration of NaHCO₃, the maximum explosion pressure (P_max), maximum rate of pressure rise ((dP/dt)_max), and explosion severity index (K_st) of bituminous coal dust decrease. When the NaHCO₃ particle size distribution is in the range of 0-45 μm with a concentration of 100%, the maximum explosion pressure and maximum rate of pressure rise for bituminous coal dust are reduced to 0.32 MPa and 16.91 MPa/s, respectively, representing a decrease of 51.5% and 55.3% compared to the original values. Additionally, characteristic parameters of explosion inhibition for bituminous coal dust with different NaHCO₃ particle sizes and concentrations are proposed. Generally, the concentration of NaHCO₃ has a greater influence on suppressing bituminous coal dust explosions than particle size. The research findings provide a scientific basis for achieving precise explosion inhibition of bituminous coal dust and enhancing targeted explosion control of bituminous coal dust.