Waid Omar

Application of Ultrasonics in the On‐line Determination of Supersaturation

An ultrasonic technique is used to develop a method based on the measurement of both ultrasonic velocity and temperature of the supersaturated media for the on-line determination of the supersaturation. It is demonstrated by the example of aqueous K 2 SO 4 solution in a seeded batch crystallizer. The feasibility of this technique was investigated using a commercial available sensor. The experimental measurements for the desupersaturation versus time trajectory proved that this technique can be successfully employed to measure supersaturation with sufficient accuracy and precision. Such sensor is preferred in the on-line application due to its fast response and the availability to be applied directly in the slurries without any need to the solid-liquid separation.

Application of pellet softening (PS) as a scale prevention method in seawater desalination plants

Abstract This research investigates the potential of pellet softening (PS) on calcite particles as a control method to avoid scaling of calcium carbonate from seawater in desalination. Experimental studies were conducted in a 5 L agitated vessel under controlled temperature and agitation. The measured transient calcium ion concentration, salinity, pH, and total alkalinity of seawater during mixing with calcite particles show that the Ryznar Stability index (RSI) increased from 4.3 to 5.7, which means that the status of seawater changed from “high scaling potential ”to “low scaling potential” after being subjected to PS process at 70°C. The supersaturation of seawater with respect to calcite is reduced from 33.5 to 5.27. The results demonstrate that PS is a feasible and effective pretreatment strategy for thermal and membrane seawater desalination facilities.