Experimental Research on the Performance of the Macromolecule Colloid Fire-Extinguishing Material for Coal Seam Spontaneous Combustion

Abstract

Coal resources are rich in China. They are mainly concentrated in the northwest region. But these resources also make the situation of spontaneous coal combustion hazards most serious in this area. Affected by the arid and semiarid climate, the water resource in this area is relatively scarce. In order to improve the utilization rate of water, a macromolecule colloid for coal mine fire fighting was developed in this research. The main components of the macromolecule colloid and the principle of gel formation were analyzed. The physical and chemical properties of the macromolecule colloid were analyzed by the time of gelation and the water loss. The water content of the macromolecule colloid was as high as 99%. The inhibition performance of the macromolecule colloid on coal fire was studied by the programmed heating device. The experimental results show that the macromolecule colloid has a significant inhibitory effect on the heating rate, oxygen consumption rate, and gas production rate. It inhibits the coal-oxygen composite by increasing the activation energy (Ea) of coal, which also has the effect of wrapping coal to isolate oxygen. The inhibition performance of the macromolecule colloid on coal fire disasters is better than that of water, water glass, loess compound colloids, and other traditional fire-extinguishing materials.

Preparation and Characterization of a Bentonite-Based Hybrid Gel for Coal Spontaneous Combustion Prevention

“…Due to its large heat capacity and adhesion, gel fire extinguishing material has advantages in lowering coal temperature, isolating coal from air and sealing air leakage, and so forth. It has achieved great success in the field of underground coal seam fire extinguishing and preventing spontaneous combustion of floating coal and become an effective means to prevent and extinguish coal seam fires. − The existing gel fire-extinguishing materials are mainly classified into inorganic and organic gels. Silicate gel formed by liquid water glass and ammonium salt or sodium bicarbonate is the most widely used inorganic gel in Chinese coal mines. − Although silicate gel has a certain fire extinguishing effect, some disadvantages, such as producing harmful gas, poor compressive strength, uncontrolled gelation time, easy powder and dry cracking after water loss, and so forth, also limit its application.…”

“…It has achieved great success in the field of underground coal seam fire extinguishing and preventing spontaneous combustion of floating coal and become an effective means to prevent and extinguish coal seam fires. 12 − 15 The existing gel fire-extinguishing materials are mainly classified into inorganic and organic gels. Silicate gel formed by liquid water glass and ammonium salt or sodium bicarbonate is the most widely used inorganic gel in Chinese coal mines.…”

Research on the Damping Performance of Mining Highly Efficient Water-Retaining Colloidal Material Against the Spontaneous Combustion of Coal

“…However, the residence time of the inert gas in the designated area is short and difficult, the effect decreases significantly when the air leakage in the area is large, and it is difficult to have extinguishing properties for the residual flame of the negative combustion [25,26]. Fire retardant technology on the one hand through the negative catalytic effect of the material to inhibit coal oxidation, on the other hand, the retardant material will be sprayed on the surface of the coal body to generate a thin film, can reduce the contact area of coal oxygen from the physical aspects of the coal body to reduce the oxygen adsorption capacity, so as to achieve the effect of preventing spontaneous combustion of coal [27][28][29], but the retardant in the high temperature after the loss of water, its fire function will also be completely lost, and some retardant in the loss of water will promote the oxidation of coal spontaneous combustion. However, after water loss at high temperatures, the fire protection function will be completely lost, and some resistants will promote oxidative spontaneous combustion of coal after water loss, so the actual field application of resistants has certain limitations.…”

“…The water in the colloidal material vaporises rapidly at high temperatures, taking away a large amount of heat and reducing the temperature of the coal. The residual colloidal shell can form a thin film covering the coal body, preventing coaloxygen contact and thus inhibiting the oxidation process of the coal body [28]; the incompletely dried colloidal body can fill the pores of the coal body and wrap the coal body, also isolating oxygen from the coal body and gradually weakening the oxidation reaction of the coal [30]. However, conventional colloidal fire protection technology suffers from high water loss of conventional colloidal material, harsh transport conditions of the base material and some materials can be hazardous to human health, which reduces the safety of the coal production process [31].…”