The Ultrafiltration Combined Process Processes High Concentration Brine Brine

Salt is not only the necessary element to human health but also an import ant raw materials in chemical production.The development of salt chemical in dustry plays an crucial role in the development of marine economy of our cou ntry.Brine is the important raw material for salt chemical industry and the ma in component of brine is sodium chloride.In recent years,with the aggravation of the ocean environment pollution,more and more pollutants including particul ate matter,colloid,organic matter,minerals and microorganisms are entering in to brine which is fabricated by seawater concentration Therefore,in order to e nsure the quality of edible salt and healthy development of salt chemical indus try,brine purification become a vital issues that cannot be negligible.Compared with the traditional brine purification process,ultrafiltration has t he advantages of small footprint,less chemical pollution;and high automation.however,membrane fouling problem is one of the major problems of limiting membrane promotion and application.The effective pretreatment of brine can effectively alleviate membrane fouli ng.As a result,the process of coagulation air flotation+sand filtration+ ultrafiltr ation was operated for the treatment of high concentration brine.Effect of diff erent running flux and pretreatment conditions on irreversible membrane fouling was evaluated,the results showed that the process of coagulation air floatation+sand filter can effectively alleviate the irreversible membrane fouling,and the optimum operating flux was 20L/m~2 ·h.The tonnage energy consumption and b rine recovery ratio was calculated in each processing unit.The tonnage energy consumption of sand filter unit,air flotation unit,and the ultrafiltration unit is 0.26kw h/m~3,0.19 kw h/m~3.0.12 kw·h/rrm~3,respectively.The brine recovery rati o was 90%when the operation flux of ultrafiltration is 20L/m~2 ·h.Both sand f iltration unit and air flotation unit were recovered completely.The influencing factors of membrane fouling rate for single cycle were an alyzed.The higher the running flux,the nore rapidly of membrane fouling rat e for single cycle.Coagulation air floatation+ultrafiltration pretreatment could ef fectively reduce the membrane fouling rate.The effects of brine treatment under different treatment processes were co mpared.The experimental results showed that coagulation air floatation+sand fil tration had better removal effect on SS?turbidity and TOC and the removal ra te were 35.6%?38.9%?38.8%?4.7%and 68.7%?73.4%,respectively.The r emoval effects of TOC and turbidity using coagulation air floatation+sand filtra tion+ultrafiltration were improved to 38.6%?44.2%and 99.6%?99.7%.The be st polyaluminum chloride dosing amount and appropriate hydraulic retention tim e of brine in the sand filter was determined.The best polyaluminum chloride dosing amount is 30?40 ppm and the hydraulic retention time of brine in the sand filter should be 3?3.5 min.