Combustion rates of pulverized coal particles in high-temperature/high-oxygen concentration atmosphere

✍ Scribed by M. Saito; M. Sadakata; M. Sato; T. Soutome; H. Murata; Y. Ohno

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 782 KB
• Volume: 87
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(91)90022-4

✦ Synopsis

Combustion characteristics of pulverized coal particles at particle temperatures over 1800"C and oxygen concentration of 40%-80% were investigated using a high-temperature drop furnace. The results demonstrate that the ignition delay time and burnout time are less than 10 and 50 ms, respectively, in the case of combustion under a high-temperature/high-oxygen concentration atmosphere. It was found that the char combustion rate was controlled by gas film diffusion, and the apparent activation energy was about 8.4 kJ/mol. Also, the rotation of pulverized coal particles was observed during early-stage of combustion and the rotation frequency reached 3000-5000 cycles/s. The combustion rate of volatile matter was remarkably increased within the range of particle temperature over 2100"C. The apparent activation energy of the combustion rate of volatile matter was increased with increasing particle temperature and oxygen concentration. The value of activation energy changed from 109.2 kJ/mol for particle temperature 1800-2100"C and oxygen concentration 40%-50% to 336 kJ/mol for particle temperature over 2500"C and oxygen concentration 70%-80%.