1-Dry air cylinder; 2-Nitrogen cylinder; 3-Three-way valve; 4-Flow sensor; 5-Air resistance; 6-Pressure gauge; 7-Steady flow valve; 8-Steady pressure valve; 9-Pressure relief valve; 10-Heat insulating layer; 11-Temperature control box; 12-Gas preheating copper tube; 13-Coal sample can; 14-Heater; 15-Fan; 16-Temperature probeFig. (1) Structure of the experimental apparatus.