Numerical simulation of soot combustion process in a bubbling fluidized bed with segregation behavior

Although only about 1wt.% soot is formed after asphalt gasification, it is generally recognized that handling of the soot places a considerable financial burden on the integrated deasphalting-gasification process, because the disposal of the filter soot to landfill or other destinations causes serious environment problems. The bubbling fluidized bed combustion process, which takes the advantage of segregation behavior, was proposed to solve soot handling problem. A multi-fluid model based on an Eulerian-Eulerian approach was developed to reveal the characteristics of segregation and combustion behavior. The distributions of flow, temperature, and species concentration were obtained, and the simulation results demonstrate that the segregation behavior is beneficial to discharge particle mixtures with low soot content at the bottom of the bed, which will favor the following vanadium recovering process. The effects of several key operating conditions, such as excess air coefficient, superficial gas velocity and initial static bed height were also discussed. (c) 2015 Curtin University of Technology and John Wiley & Sons, Ltd.