Experimental study on optimizing the inhibition effect of pre-injection inhibitor on coal spontaneous combustion

It is an important measure to inject inhibitor into coal to prevent coal spontaneous combustion (CSC) disasters. At present, it is still a topic worth discussing about the factors affecting the preventing effect of inhibitors on CSC. For this topic, MgCl2, CaCl(2)and NH(4)H(2)PO(4)were firstly selected as inhibitors in this paper to carry out the experiment of pre-injection of inhibitors in coal samples and obtain the coal samples injected with inhibitors. Four factors (injection pressure, injection time, concentration of inhibitor, type of inhibitor) affecting the results of inhibition were analyzed by orthogonal statistical method (OSM). After that, the temperature rise experiment was carried out for the raw coal sample and the coal sample injected with inhibitor. The results showed that: when the concentration of the inhibitor was 25%, the injection pressure was 4MPa and the injection time was 2d, a better pre-injection effect could be achieved. The inhibition rate of coal samples injected with NH(4)H(2)PO(4)was 25.7%, which was higher than that of MgCl(2)and CaCl2. Therefore, the inhibitor of NH(4)H(2)PO(4)injected into coal samples can achieve relatively good inhibition effect. The above contents hope to provide a certain basis for the prevention and control of coal-mine fire.