A lab-scale cold flow model reactor to investigate near-wall particle segregation relevant to entrained-flow slagging coal gasifiers

This paper reports on preliminary results of an experimental investigation aimed at the development of a phenomenological model of the fate of coal/ash particles in entrained-flow slagging coal gasifiers. The study specifically addresses the interaction between the lean-dispersed particle phase and the reactor walls, and the establishment of a particle segregated phase in the near-wall region of the gasifier. Better mechanistic understanding of particle-wall interaction patterns in entrained-flow gasifiers is pursued using the tool of physical modeling. To this end a lab-scale cold flow reactor (0.04 m-ID) has been designed and set up, where molten wax is air-atomized (droplets of 50-100 mu m size) into a mainstream of air to simulate the near-wall fate of char/ash particles in a real hot environment. Preliminary characterization of the hydrodynamics of the lean-dispersed phase, of its interaction with the wall, of the buildup of the liquid wall layer has been accomplished with a focus on the "sticky wall-sticky particle'' sub-regime.