1. Combustion of a coal char particle in a stream of dry gas
- Author
-
F.J. Higuera
- Subjects
Range (particle radiation) ,Drag coefficient ,Chemistry ,020209 energy ,General Chemical Engineering ,Diffusion flame ,General Physics and Astronomy ,Energy Engineering and Power Technology ,Mineralogy ,02 engineering and technology ,General Chemistry ,Mechanics ,Combustion ,Aeronáutica ,Fuel Technology ,020401 chemical engineering ,13. Climate action ,Drag ,0202 electrical engineering, electronic engineering, information engineering ,Particle ,Char ,Particle size ,0204 chemical engineering - Abstract
The burning rate, surface temperature, drag, and extinction conditions of a single char particle moving in a gas are computed numerically. The effects of the size and velocity of the particle and of the temperature and composition of the gas are examined in the framework of a simple model that includes O2 and CO2 heterogeneous reactions and, in some cases, a diffusion-controlled CO oxidation flame in the gas around the particle. In agreement with known results, the burning rate is found to increase with the velocity of the particle when the Reynolds number of the gas flow ceases to be small. The temperature of the particle increases with the temperature and oxygen mass fraction of the gas and is little affected by the size and velocity of the particle, except in the vicinity of extinction. The drag coefficient is a decreasing function of the particle size and velocity in the range of Reynolds numbers that has been analyzed. The presence of CO2 in the gas may have an important effect on the gasification of small particles.
- Published
- 2008