Experimental study on inhibition of coal spontaneous combustion by hydroxyethylene diphosphonic acid

Abstract

In order to study the effect of hydroxyethylene diphosphonic acid（HEDP） on the characteristics of coal spontaneous combustion, a temperature-programmed gas chromatography experiment was carried out to compare and analyze the production and development of the marker gases between raw coal sample and HEDP inhibited coal sample, and the inhibition rate of HEDP inhibitor on experimental coal samples. At the same time, the characteristic temperature points and heat release characteristics of experimental coal samples in the process of coal spontaneous combustion and oxidation were analyzed by synchronous thermal analysis device. The temperature-programmed gas chromatography experimental results show that, in the process of coal spontaneous combustion oxidation, HEDP inhibitor can reduce the amount of CO gas release, and with the increase of temperature, the inhibitory effect of HEDP inhibitor on coal spontaneous combustion is gradually enhanced. For the coal with more transition metal ions in the coal, the HEDP inhibition effect is more obvious, and the inhibition rate of fat coal（ＦＭ） is up to 51.74%, while that of gas coal（ＱＭ） is down to 16.74%. The synchronous thermal analysis experimental results show that the HEDP inhibitor can act on the whole process of coal spontaneous combustion and oxidation. In the early stage of coal spontaneous combustion and oxidation, the HEDP inhibitor can inhibit coal spontaneous combustion and oxidation. HEDP inhibitors can significantly increase the drying and cracking temperature, ignition temperature, maximum thermal weight loss rate temperature, etc., and reduce the maximum heat release power and total heat release in the process of coal spontaneous combustion oxidation.

Keywords

• inhibitor
• transition metal ions
• inhibitor rate
• characteristic temperature
• heat release characteristics