Scaling is a major problem in the thermal desalination operation which is mainly attributed to the deposition of salts on the tube, thereby increasing the resistance to heat transfer. To reduce or prevent the formation of scale on heat transfer surfaces, treating desalination concentrates and precipitating sparingly soluble salts can be a promising method. In the present work, the effect of ultrasound pretreatment to the synthetically prepared sea water as desalination feed has been investigated with an objective of intensifying salt removal process and avoiding scale formation leading to better heat transfer rates. A lab scale double pipe heat exchanger setup was designed and operated under simulated conditions of the thermal desalination operation. Total operational volume of 2000 ml was used for all experiments with a fixed flow rate of 5 ml/s. To understand the process of scaling, synthetic seawater was prepared as per the ASTM D 1141-98 and was used for scale deposition experiments. The experiments conducted using untreated synthetic seawater confirmed substantial scaling and drop in the heat transfer coefficient from an initial value of 776 W/m² K to 603 W/m² K (about 22%) after 24 h operation as compared to deionized water. SEM-EDX analysis was performed to investigate the morphology and main components of the scale. Subsequently, synthetic seawater was treated with ultrasound under continuous flow condition for removal of salts responsible for scaling. It was demonstrated that pretreatment resulted into salt crystallization, after which, the crystals were separated and the filtered solution was passed through the heat exchanger to check the effects on heat transfer rate. It was confirmed that the heat transfer rate was found to be higher with a value of 797 W/m² K. Overall an effective approach based on ultrasound to remove the scale forming components has been demonstrated with established best conditions as 70% amplitude for 30 min of irradiation at fixed frequency of 20 kHz and 50% duty cycle.

结垢是热脱盐操作中的主要问题，其主要归因于盐在管上的沉积，从而增加了对热传递的抵抗力。为了减少或防止在传热表面上形成水垢，处理脱盐浓缩物和沉淀微溶盐可能是一种有前途的方法。在目前的工作中，已经研究了超声预处理对作为脱盐进料的合成海水的效果，其目的是增强除盐过程并避免结垢，从而导致更好的传热速率。设计了实验室规模的双管换热器装置，并在模拟条件下进行了热脱盐操作。所有实验均使用2000 ml的总操作体积，固定流速为5 ml / s。为了了解结垢的过程，按照ASTM D 1141-98制备了合成海水，并用于结垢实验。使用未经处理的合成海水进行的实验证实了结垢和传热系数从初始值776 W / m下降 与去离子水相比，在24小时运行后²  K至603 W / m ² K（约22％）。进行了SEM-EDX分析以研究量表的形态和主要成分。随后，在连续流动条件下用超声波处理合成海水，以去除造成结垢的盐分。结果表明，预处理导致盐结晶，然后分离晶体，将过滤后的溶液通过热交换器，以检查其对传热速率的影响。确认发现传热速率更高，值为797 W / m ² K.总的来说，已经证明了一种有效的基于超声波的方法来去除水垢形成成分，并已确立了最佳条件，即在20 kHz固定频率和50％占空比下辐照30分钟可获得70％振幅。