Experimental Investigations on Foaming Device Used for Coal Spontaneous Combustion Prevention

Foamed gel is widely used for coal spontaneous combustion prevention in coal mines, and foaming device is the key part for foamed gel preparation. The device is mainly composed of reducing pipeline, diffuser, and convection adder, mixing plate, of which the inlet and outlet radius of reducing pipeline are 30 mm and 7.5 mm, the distance between diffuser and the outlet of the reducing pipeline is 20 mm. Further, foamed gel preparation system based on foaming device is built in lab, and the optimum preparation procedures and parameters are obtained with water flow volume 4 m(3)/h, air pressure 0.4 MPa. The final foam multiple is 15 times, gelation time is 100-500 s. Field application on coal self-ignition prevention showed that this new foaming device could produce a large amount of foamed gel to meet the application. Therefore, it is believed that this study laid an important foundation for the widespread application of foamed gel technology for coal spontaneous combustion control in coal mines.