本文分别用经过脱硬预处理的海水和传统预处理的海水（以下称海水）进行水平管降膜蒸发实验。实验结果表明，在沸点低于70℃时，随着沸点的升高，两者的传热系数都逐渐增大，但脱硬后海水的传热系数略高于海水；在沸点高于70℃时，脱硬后海水的传热系数远远大于海水。也就是说，脱硬后海水可以在高温时也达到很高的传热系数，从而为脱硬预处理与多效蒸发系统相结合提供了实验与设计基础。

 In this paper, seawater with simple pretreatment and seawater with softening pretreatment were used to horizontal tube falling film evaporation experiments respectively. Experimental results showed that these two heat-transfer coefficients gradually increased with boiling point ,and the heat-transfer coefficient of seawater with softening pretreatment was slightly higher than seawater’s when the boiling point was below 70℃; The heat-transfer coefficient of seawater with softening pretreatment was much higher than the seawater’s when the boiling point was above 70 ℃. In a word, seawater with softening pretreatment could achieve high heat-transfer coefficient at high temperatures. The experiment provided the experimental and designed base for the combination of softening pretreatment and multiple effect evaporation system.

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