A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed

摘要: Spout fluidized beds find widespread application in the process industry granulation processes, which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding complex behavior these systems lacking. In this paper we study effect inter-particle interaction on bed dynamics, by investigating height, pressure drop vertical particle velocity as function variable restitution coefficient, varies time space moisture content due to particle-droplet interaction. This done computationally, using extended discrete element model (DEM) describes dynamics continuous gas-phase particles droplets. The objective work gain insight coefficient flow spout at different regimes DEM. three comprise intermediate / spout-fluidization regime (B1), spouting-withaeration (B2) jet-in-fluidized-bed (B3). simulation results with coefficients were compared simulations constant reported Van Buijtenen et al. (2007). trend increasing average height decreasing also valid for coefficient. larger all regimes. observed drop, showing a lower value These suggest significant influence since provides regions having collision properties. presence distinctive causes shown time-averaged velocity. region than case B1 B2. B3 are less pronounced, mixing capacity caused channel bubbles annulus region. As result, complies findings reveal impact bed, clearly can only be simulated when dependency accounted for. Currently, wetting has been without evaporation crystallization deposited granulate solution, phenomena that very important process. It therefore desirable further improve model, solving mass energy balances phase.