低温多效蒸馏海水淡化无磷阻垢剂复配研究

Compound additives of phosphorus-free scale inhibitor for low-temperature multi-effect distillation seawater desalination

选取开发合成的AA-AM-HPA(丙烯酸-丙烯酰胺-丙烯酸羟丙酯)三元共聚物及几种单剂进行无磷阻垢剂复配试验,模拟LT-MED(低温多效蒸馏)低温负压蒸发环境进行动态试验,并考察阻垢剂的缓蚀性能,通过电化学测试和SEM(扫描电子显微镜)探究阻垢缓蚀机理。结果表明:MA-AA(马来酸-丙烯酸共聚物)和AA-AM-HPA以质量比2:1比例复配时效果最好,静态阻垢率达78.50%,在67℃浓缩2倍海水情况下HA177-2铝黄铜的腐蚀速率为0.127 mm/a。动态模拟试验结果显示,加药量为5 mg/L时,复合阻垢剂的钙和硫酸钙阻垢率分别达70.45%和89.71%,优于所选商品阻垢剂。电化学测试和SEM结果表明阻垢机理主要为晶格畸变作用,缓蚀机理属于混合型,主要抑制阳极反应。因复合药剂存在溶限效应,综合考虑阻垢缓蚀性能和经济性,建议加药量为5—10 mg/L。

The synthesized scale inhibitor AA-AM-HPA terpolymer and several scale inhibitors were selected to carry out a series of phosphorus-free scale inhibitor compound experiments.A dynamic test was carried out by simulating the low temperature and negative pressure evaporation circumstance of LT-MED and the corrosion inhibition performance of scale inhibitors was investigated.Moreover,the mechanism of scale inhibition and corrosion inhibition was explored by electrochemical test and SEM.The results show that MA-AA and AA-AM-HPA have the best scale inhibition effect at the mass ratio of 2:1,and the static scale inhibition rate is 78.50%.The corrosion rate of HA177-2 aluminum brass is 0.127 mm/a at 67℃when the seawater concentration is doubled.Besides,the results of dynamic simulation test show that when the dosage is 5 mg/L,the scale inhibition rate of calcium and calcium sulfate of the compound scale inhibitor reaches 70.45%and 89.71%,respectively,which is better than that of the selected commercial scale inhibitors.In addition,the electrochemical test and SEM results show that the main mechanism of scale inhibition is lattice distortion,and the compound additive belongs to a mixed-type inhibitor,which mainly suppresses anode reaction.What′s more,the compound scale inhibitor reflects a threshold effect.Considering the scale inhibition and corrosion inhibition performance and economy,the dosage of scale inhibitor is recommended to be 5-10 mg/L.