本发明提供一种正渗透作为预处理的热法海水淡化技术,包括正渗透单元和热法海水淡化单元。所述的正渗透作为热法海水淡化单元的预处理步骤可截留进料海水中的离子,进料海水中的水由于渗透压差作用由原料液侧跨膜进入汲取液侧。所述的热法海水淡化单元用于正渗透汲取液的回收与淡水的产生,可采用多效蒸发或多级闪蒸。正渗透作为热法海水淡化的预处理步骤,可使得进入热法海水淡化单元的溶液RSI提高,结垢倾向大幅降低,从而减少阻垢剂的投加量,同时可以提高多效蒸馏系统顶温,减小换热面积,降低成本。

The invention provides a thermal seawater desalination technology with forward osmosis as the pretreatment, which includes a forward osmosis unit and a thermal seawater desalination unit. The forward osmosis as the pretreatment step of the thermal seawater desalination unit which intercept the ions in the feed seawater. The water in the feed seawater then enters the draw liquid side from the raw material liquid side across the membrane due to the effect of the osmotic pressure difference. The thermal seawater desalination unit is used for the recovery of forward osmosis extraction liquid and the production of fresh water, and the multi-effect evaporation or multi-stage flash evaporation is also adopted. As a pretreatment step of thermal seawater desalination, forward osmosis can increase the RSI of the solution entering the thermal seawater desalination unit and greatly reduce the scaling tendency, thereby reducing the dosage of scale inhibitors, increasing the top temperature of the multi-effect distillation system, reducing the heat exchange area and the cost.