Development And Performance Evaluation Of Special Scale Inhibitor For The Multi-effect Distillation Desalination

The special scale inhibitors for multi-effect distillation desalination were developed, and the performance of the inhibitors was evaluated in this research under the background of thermal desalination. The development of scale inhibitor used in thermal desalination, and the new scale inhibitor formulas were carried out. The new inhibition performance evaluation method in sea water system called Copper Deposition Method (CMD) was established. Otherwise, the mechanism of inhibition was discussed through two aspect. Five inhibitor formulas (formula 1 to formula 5) were obtained in this research, and its performance was evaluated through the national standard method (GB/T 16632-2008) and CMD.And the action mechanism of scale inhibitor was studied through analyzing the scale samples using Scanning Electron Microscopy(SEM), X-ray diffraction(XRD)and Particle Size Analysis(PSA).As was shown in the national method, the anti-scaling performance of formula 1 and formula 2 is lower than Belgard EV 2050, but similar to Belgard EV 2035.When the inhibitor concentration ranged from 6mg/L to 15mg/L, the inhibition rate keeps at from 65% to 70%. The inhibition rate of formula 3,formula 4 and formula 5 is better than that of Belgard EV2035 and Belgard EV2050. Besides, scale inhibitor can act on the character of scale. SEM results show the scale appearance changed totally under the action of scale inhibitor. And effect of the formulas in this research on scale appearance is similar to that of Belgard EV 2035 and Belgard EV 2050.On the basis of thermal seawater desalination operation conditions, the CDM was forged. And this method supplement the inhibitor performance evaluation, which delivers the action of inhibitors on the characteristics of scale. The CDM results show that formula 4 and formula 5 have improved inhibition performance. And it gets the best result when the inhibitor concentration is at 6mg/L. When the temperature varies from 70℃to 90℃, formula 5 showed the similar performance to Belgard EV 2035.This results contributes to industrial application of the inhibitor formulas produced in this research.The mechanism of inhibitors was studied trough two aspects. One is the Solubility-Improving Action(SlA), and the other is Anti-Adhesion Action(AAA).