Application Of Seeding Crystallization as a Pre-Treatment Stage for The Reduction of Scaling Tendency of Seawater Feed to Thermal Desalination Units

The fouling inhibition in seawater desalination and scale control using crystallization with calcite seeds is evaluated experimentally in this study. The growth kinetic parameters are determined experimentally, correlated and discussed at different operating conditions. Supersaturation levels represent driving force behind the growth of crystals, which is influenced directly by seawater pH values and temperatures. Results indicate that the initial pH value of seawater must be controlled to be in the range (8-9) and calcite seeds will not have the potential to start the growth process in seawater at the normal pH (7.36). The growth kinetic parameters are determined from the measured desupersaturation curves. It is found that the growth process of calcite is controlled by the surface integration step. The growth rate of calcite increases with increasing temperature and seeding ratio (up to 1 g/L), while it decreases with increasing the salinity of seawater.