(113d) Numerical and Experimental Investigation of Dry Particulate Fouling

Particulate fouling is one of the major forms of gas side fouling in heat exchanger systems. Numerical modeling of fouling has been an evasive task. One of the reasons for this is attributed to the lack of detailed experimental data. In-situ fouling experiments in real gasifier systems involve too many lumped parameters and are not very suitable in numerical modeling of the process. On the other hand, controlled lab-scale experiments that have been reported are meager and those that have been published are performed either at low temperatures or at very high temperatures (>1000 ^oC). In this direction, a high temperature controlled fouling experimental facility has been built to elucidate the effect of various parameters on fouling like: gas phase velocity, gas phase temperature, particle types and properties, tube shape and geometry. Experiments with different seeding particles and target geometries are performed under various temperatures and velocities. It is noted that the process of fouling is greatly influenced by the gas phase velocity i.e. shear due the gas phase, temperature, surface roughness of the tube and the presence of condensable species in the gas. As inertial impaction is reported to be the major mechanism involved in the particle deposition, a numerical model based on Elastic-Plastic deformation of impacting particles and removal by shear is presented and compared with the experimental observations.