Effect of particle impact velocity on carryover deposition

Carryover deposition by inertial impact on heat transfer surfaces causes severe operational problems in kraft recovery boilers. This work investigates within an entrained flow reactor the effect of particle impact velocity and particle size on deposition rate and characterizes the dynamic sticking behavior of synthetic carryover particles upon impact on a surface. The results show that the deposition of 210 μm particles is independent of velocity over the range 1.8 to 12 m/s, however, for larger particles of 390 μm an increase in velocity decreases the deposition rate. The effect of particle size on adhesion efficiency is negligible at very high velocity for partially molten particles over the 90–425 μm size and 1.8–12 m/s velocity range studied. A portion of partially molten particles rebound off the probe and in some cases the solid part of particles rebound while the liquid part freezes on the surface. All molten particles spread and freeze on the surface.