微咸湖泊反渗透脱盐无机结垢风险评价及静态阻垢技术研究

针对微咸水湖泊水体反渗透(RO)脱盐过程中的膜表面无机钙垢问题,采用陶氏Rosa软件与海德能的IMSDesign膜设计软件,分析了不同工艺条件下RO膜的无机结垢风险。以岱海原水为研究对象,模拟研究了RO系统在回收率20%~70%、温度5℃~35℃、pH6.5~9.5和矿化度3~15 g/L等条件下运行效能,随着回收率、温度、pH增加,RO设备运行时膜的无机结垢风险逐渐增加,尤其是在回收率、温度和矿化度分别高于28.0%、6.80℃和3 g/L时,需要投加一定浓度的阻垢剂。研究以应用广泛的聚天冬氨酸(PASP)作为阻垢剂,采用CaCl 2溶液进行阻垢预试验,确定了适宜的PASP投加率为0.002 mg PASP/mg Ca^(2+)。采用岱海典型原水进行静态阻垢试验,受其他阳离子的影响,适宜的PASP投加率为0.04 mg PASP/mg Ca^(2+),阻垢率可达78.97%以上。

Photovoltaic Powered Reverse Osmosis Plant for Brackish Water without Batteries with Self Acting Pressure Valve and MPPT

This paper presents a PV （photovoltaic） powered RO （reverse osmosis） plant for brackish water without batteries and a self-regulating pressure valve. The aim is to extract the maximum power from the PV module using an MPPT （maximum power point tracking） technique for powering a solar water pump and maintain constant the pressure in the RO membranes by using the self-operated valve. A Buck type converter using the InCond （incremental conductance） MPPT was developed for this application. The MPPT chosen was simulated, tested and validated, showing an efficiency of 86.8%. The technical feasibility of the RO plant was made by PLC （programmable logic controller） and was tested for two salinity levels （1,000 and 1,500 mg/L of TDS （total dissolved solids））. These salinity levels chosen are commonly found in most brackish water wells of the semi-arid region of Northeastern Brazil. The RO plant could permeate 175.3 L/day of drinking water with 120 mg/L of TDS and specific energy consumption of 2.56 kWh/m3.