Design of Process and Monitoring System for Introducing Flue Gas from Power Plants into Mined-Out Area

Due to the combination of coal and electricity in the construction process, numerous pithead power plants have been established around coal mines. The release of flue gases from these power plants has put a strain on managing atmospheric environmental issues. Utilizing flue gas for fire prevention and control in mined-out areas can significantly reduce the cost of nitrogen production while achieving a secure and environmentally friendly approach to handling flue gas. Flue gas is a product of coal combustion with a low oxygen content and possesses the properties of inert gas. In this paper, the feasibility of flue gas inerting mined-out area is determined by analyzing the main components of flue gas, the mechanism of inhibiting spontaneous coal combustion, and the content of harmful gases. The smoke monitoring system has been introduced into the goaf of power plants, achieving safe, accurate input and automated control of smoke injection into the goaf of power plants. The following conclusions are drawn: (1) The analysis shows that the oxygen content of the flue gas for the Great South Lake Power Plant is 6%, causing in the minimum flue gas injection volume of toxic and harmful gases exceeding the standard (8820m3/h) is much larger than the actual injection volume (2000m3/h), and the feasibility of the inerting of flue gas in mined-out area has been determined. (2) Installation of various sensors in the flue gas pre-treatment workshop, conveying pipelines and coal mining face. Continuous monitoring of environmental parameters, flue gas pipeline parameters, equipment working condition parameters, etc. in the well and underground have been realized. The process of automation “flue gas extraction—flue gas treatment—flue gas injection” is realized by the method of “PLC controller + monitoring substation + configuration software”.