Bubble Behavior And Particles Entrainment In Fixed Valve Tray Column

This study was motivated by entrained-flow coal gasification technologies which was the study background, the fixed valve tray in syngas purification process was the study object, Deeply study for the bubble behavior in foam layer, entrainment of particles, precursor film on particles by different experimental apparatus were made. A series of study results were as follows:The vertical distribution of bubble movement above the fixed valve tray plate was studied by double conductivity probe. The fractal characteristics and distribution of bubble velocity in different vertical height was studied, as well as the behavior of bubble movement in different foam zone, The foam zone could be divided into five areas as turbulent generate area, strong turbulent area, turbulent relaxation area, weak turbulent area and turbulent reappear area. The coalescence and breakup of bubbles also have connection with the distribution of gas holdup.The contact angle was tested by the Optical contact angle measuring device, the relationship of the distribution of polar sites with precursor film behavior was studied, got that, when the fly ash in fixed bed gasification process dealt with different density NaCl solution, the higher the concentration of NaCl solution was, the smaller the contact angle was; when the fly ash dealt with higher density NaCl solution, The more densely distribution of polar sites was, the faster precursor film spread on particle surface in steady state of wetting. Prior to the steady state of wetting, the higher concentration of NaCl solution was, the faster the film spread. All of them could give the reason for why the fly ash was hardly removed by the wetting scrubbing process.The entrainment of fine particles (0.02-11μm) in fixed valve tray column was studied by high speed camera and samples from different foam height. Follows were got:in the same liquid flow and different gas flow, the distribution of particles concentration was different; particles in 0.02-0.4μm and 1-11μm had different behavior by the effect of foam entrainment, and knew that the critical size of particles dominated by foam entrainment was 0.4-1μm which was effected by the gas flow rate and concentration of particles in grey water.