Role of temperature, roughness and pressure in crystallization fouling from potable water on aluminium surface

This work evaluates the influence of surface temperature, roughness and system pressure on the crystallization fouling from potable water on an aluminium substrate. Experiments were conducted using two apparatus; one for temperature and roughness tests and another setup for pressure investigations. The findings show that a porous film of aluminium oxide forms on the aluminium substrate under all test conditions. Both temperature and surface roughness enhance the fouling rate with no obvious changes in the structure of the fouling layer. However, magnesium-calcium deposits were observed at the early stages of surface deposition. System pressure reduces the resistance to heat transfer as well as the scale amount on the surface. Moreover, the increase in pressure produces composite fouling of magnesium carbonate and calcium carbonate.