Cold flow mixing rates with recirculation for pulverized coal reactors

Abstract

Abstract The mixing of particles and gases in confined, coaxial jets in the presence of recirculation was studied. Particle and gas mixing rates were measured for conditions simulating processes involving pulverized coal combustion and entrained gasification. The effects of mixing chamber diameter, gas velocity, particle size, and particle loading level on mixing rates were determined from particle mass flux and gas tracer measurements. In every case, the gas mixed much faster than did the particles. Introduction of an expanded mixing chamber of larger diameter (with recirculation zone) significantly increased both gas and particle mixing rates over that for a smaller mixing chamber without recirculation. However, this observed increase was not strongly dependent upon the diameter of the larger mixing chamber. Increasing secondary velocity also increased mixing rates significantly.