The deposition of carryover, or molten and partialy molten smelt and black liquor particles, is a primary source of plugging of flue gas passages within kraft recovery boilers. An improved understanding of how an individual particle impacts onto a heat transfer surface may result in strategies for reducing the deposition rae. A numerical model has been developed to simulate molten carryover droplet impact, to assess the influence ofparticle size, velocity andparticle fluid porperties on the consequent impact dynamics. Results of parametric studies using the model show that the liquid surface tension and the wetting behaviour of the liquid on the surface strongly affect the impact of small paritcles(diameter < 0.5mm). Small particles are shown to spread uniformaly and without disruption, and are likely ot stick on impact. As the particle size and impact velocity increase, iertial effects become more significant. Particles larger than 1 mm will tend to splash on impact, forming small satellite particles which do not stick ,and which may account for the presence of the small carryover particles found in precipitator dust.
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