Experimental Study On Wetting Coal By Surfactant

Wetting coal is comprehensive index of colliery disasters. But to achieve good results depends on the uniform coal wetting. Wet coal for the prevention of coal and gas outburst, and prevention gas concentrations beyond the limit in the mined-out area and tunnelling face etc, has certain effect. But because of coal itself influence, for example, the factors of formation, composition, degree of deterioration and crack development etc., result in different effect of wetting coal. In order to control coal mine disaster accidents effectively, as gas explosions, coal and gas outburst etc., the water is added by surfactants to reduce its surface tension. By way of injection or spray, surfactant solution can contact with the coal, enhance the surfactant solution in the coal penetration and diffusion to realize the effect of evenly wetting coal.This paper selected coal samples from Pingdingshan Mine, Zhaogezhuang Mine, Tangshan Mine, Huaibeiluling Mine, Xinlonghongling Mine, and selected six suitable for mining of surfactants for the research object. Because of single function of surfactant, this will be selected relatively simple of surfactants in compliance with principles of orthogonal with experiment to get better performance of surfactant. Using FTA200 video detector measure of surface tension and the solution and coal sample with the contact angle, analyzing all the coal sample best effect of wetting are concentration greater density critical micelle concentration (cmc) of F7 - c3 solution.According to the theory of capillary, the calculated wetting driving force produced inside the coal capillary hole wall: sprayed self-made surfactant solutions of coal samples than spraying water coal sample at least improve 1.7 times, make wetting more fully and more uniform. And produce wetting driving force in a certain degree of gas in the pore blocking, reduce or delay to release a quantity of gas, prevent gas concentrations beyond the limit, which has certain effect.Analyzing four parameters of the surface tension, contact angle, wetting velocity and wetting driving force to evaluate the effect of coal wetting, wetting velocity is the best indicator.Through the experiments of gas absorption and desorption, contrast analysis gas desorption quantity of water spray and self-made surfactant solutions spray, it is obtained that the coal sample from Zhaogezhuang Mine under different pressure gas adsorption effect of gas emission hinder is the best, the coal sample from Pingdingshan Mine is the worst. At 0.3 MPa, 0.5 MPa and 0.7 MPa pressure gas absorption, gas desorption quantity of all the coal sample is different, blocking effect of gas is different. With the pressure value of adsorption coal sample gas reducing, the rate of gas desorption quantity reduction increases, which hinder the better the effect of gas emission. By surfactant F7 solution wetting coal samples, blocking effect in low pressure gas is good, in high pressure is relatively poor.