Abstract:

Aiming at the problem that the concentrated water reverse osmosis silicate scale in demineralized water system is difficult to clean, chemical cleaning with H₂SO₄/GA(gallic acid) mixture can effectively reduce the content of polysilicon in the reverse osmosis membrane. With the increase of GA content in H₂SO₄/GA mixture, the content of polysilicon in reverse osmosis membrane decreases. From the aspects of economy and effect, when the mass fraction of GA is 7.5%, the cleaning effect reaches the critical state, the maximum removal rate of polysilicon can reach 70%, and the membrane outlet pressure is 0.29 MPa higher than the original condition. The water production of the cation exchanger, the anion exchanger and the mixed ion exchanger increases by 314.8%, 514.0% and 133.1% respectively, and the water production ratio decreases to 1.07.The comprehensive cost is reduced by about 8% in the medium and long term application, and the implementation effect is good.

Key words: GA, reverse osmosis membrane, chemical cleaning, polysilicate fouling, H2SO4, demineralized water system, membrane resistance, gained output ratio(GOR)

摘要：

针对除盐水系统浓水反渗透装置硅酸垢难以清洗的问题，采用H₂SO₄/GA(没食子酸)混合液进行化学清洗，可以有效降低反渗透膜中聚合硅的含量。随着H₂SO₄/GA混合液中GA含量的增加，反渗透膜中聚合硅的含量呈降低趋势。从经济性和清洗效果两个方面考虑，当GA质量分数为7.5%时，清洗效果达到临界状态，聚合硅的最大去除率可达70%,膜出口压力比原始工况升高了0.29 MPa;应用全膜法进行制水实验，阳床、阴床周期产水量分别增加了314.8%,514.0%,混床周期产水量增加了133.1%以上，制水比降至1.07左右；中长期应用时，综合成本降低了8%左右，效果良好。

关键词: GA, 反渗透膜, 化学清洗, 聚硅酸结垢, H2SO4, 除盐水系统, 膜阻力, 制水比