Flame propagation in co-fired coal-natural gas mixtures

This paper describes an experimental investigation of flame propagation in turbulent streams of pulverized coal-natural gas mixtures co-fired in a tubular apparatus. Experiments were conducted in a horizontal flame tube of 52.5 mm inside diameter and 3658 mm length. The effects of particle diameter, volatile content of coal particles and gas stream Reynolds number are presented. The flame front position was timed using two photo-diodes separated by 1829 mm from each other. Results show that: (1) the flame speed increases with an increase in Reynolds number of gas-air mixture stream; (2) the flame speed attains a maximum value at a certain critical dust concentration; (3) the flame speeds increases with the decrease in particle mean diameter; and (4) the higher volatile content increases flame speed