反渗透海水淡化(SWRO)能量回收技术应用分析

反渗透技术已经在国内外的海水淡化工程中得到广泛应用,能量回收装置的应用使得反渗透海水淡化产水能耗大大降低,制水成本大幅下降。本文简要介绍了反渗透海水淡化能量回收技术及其经济成本分析,反渗透海水淡化能量回收装的分类,并对主流能量回收装置进行比较分析。SWRO系统中的流体能量回收利用技术有着良好的前景。     

海岛反渗透海水淡化技术发展现状与研究前景

我国海岛开发利用程度较低,维权形势十分严峻。反渗透海水淡化技术具有淡化效率高、能耗低、投资低等优点,可以解决海岛供水问题。本文通过介绍反渗透膜、预处理和能量回收三项技术发展现状,指出我国海岛反渗透海水淡化具有广阔发展前景。     

大型反渗透海水淡化工程能耗降低方法探讨

探讨了降低海水淡化能耗的方法,对能量回收装置性能进行了对比分析,并对大型反渗透海水淡化工程提出了"深井取水 预处理(UF/MF) 高产水量RO膜 AT TURBO/PX"工艺,提高反渗透装置进膜压力、平均膜通量、回收率,降低吨水能耗,对今后大型反渗透海水淡化工程设计有一定的借鉴意义.     

反渗透海水淡化系统中的能量回收

反渗透海水淡化中的能量回收问题一直是研究的热点。本文介绍了能量回收技术的发展、不同技术在操作和设计上的差异，重点说明了能量回收装置在反渗透海水淡化降低能耗的重要作用，能量回收技术的不断进步使得反渗透海水淡化应用日益广泛。     

能量回收装置在海水纳滤脱盐系统中的应用分析

纳滤膜分离技术对2价离子的独特分离功能,使其在海水淡化脱盐、水软化处理等领域具有广泛的市场应用。针对实际工程中海水纳滤脱盐系统的节能需求,建立了"纳滤+能量回收"耦合工艺流程;研究分析了自主开发的能量回收装置产品与纳滤脱盐系统的耦合运行特性,及能量回收装置对系统运行能耗降低的实际贡献率。结果表明,自主开发的能量回收装置与海水纳滤脱盐系统的耦合运行稳定性良好,装置能量回收效率高达96.28%,对纳滤脱盐系统本体运行能耗的降低幅度可达44%。     

反渗透海水淡化中差动式能量回收装置的研究

研究了一种应用于中小型反渗透海水淡化装置的新型差动式能量回收装置.结果表明,使用本能量回收装置的日产10m3反渗透海水淡化装置的单位淡水能耗只有3.6kWh/m^3,不考虑高压泵及电机自身损耗的影响时,单位淡水能耗为2.3～2.7kWh/m^3,装置能耗显著降低,能量回收效率达到97%.此能量回收装置不需要其它附加增压设备,并且能有效改进由于阀门开闭导致系统压力波动而造成的淡水产量不稳定的问题,保护了反渗透膜、高压泵等系统内的重要设备.     

海水反渗透淡化系统的能耗

通过对海水反渗透淡化系统（SWRO）吨水成本的分析，提出降低SWRO能耗的解决措施，采用能量透平装置（TURBO）或压力转换器（PE）回收浓水的能量传递于进水，不仅可以降低吨水电耗，也可减小一次性投资。值得关注的是，压力转换器，回收效率可达94％，在海水淡化系统中对于降低能耗有更重要的意义。     

反渗透海水淡化技术在北方海岛的应用实例

为解决长岛有人居住岛屿用水高峰期用水供需矛盾,确定采用以反渗透（RO）技术为核心的海水淡化工艺建设海水淡化站。介绍了反渗透海水淡化技术在长岛8个岛、9处海水淡化站的应用情况。该项目根据不同的海岛条件采用了不同的取水方式和预处理方案,主处理工艺采用二级砂滤+一级反渗透+二级反渗透+矿化的组合工艺,消毒采用现场制备次氯酸钠和管式紫外线方式,总制水量达5 200 t/d,出水水质达到了《生活饮用水卫生标准》（GB 5749—2006）标准。采用等压正位移式能量回收装置,总体节能率可达60%,产水耗电量为4.60 kW·h/t,总计产水成本为6.075元/t。该项目在1.5 a的运行时间内,出水效果稳定,可为北方海岛小规模海水淡化建设项目提供借鉴。     

国产万吨级低温多效海水淡化技术应用

介绍了神华河北国华沧东发电有限责任公司国产万吨级低温多效海水淡化装置的工艺流程、工作原理、技术特点,研究了海水淡化装置对天然海水温度、加热蒸汽压力等外部参数变化的适应性,分析了影响淡化装置制水经济性的因素,并讨论了淡化装置的负荷调节特性.试验结果表明,本套国产化装置运行稳定,制水负荷可在40%～110%之间灵活调节,产品水水质优良,达到了生活饮用水卫生标准.     

大鱼山岛光伏太阳能海水淡化示范工程

容量为5 m3·d-1光伏太阳能海水淡化示范工程在舟山市岱山县大鱼山岛建成,该工程主体装置采用光伏太阳能系统供电;自主研发的小型预处理装置有效解决了海水浊度的预处理问题,采用自主研发的能量回收装置使运行能耗大大降低,充分发挥了太阳能发电系统的效益.该系统运行稳定,操作简便,产水符合国家生活饮用水标准.     

太阳能膜蒸馏系统进展与展望

海水淡化技术可有效解决现有的淡水资源短缺等问题,但受限于高成本、高能耗、低热效率等因素,传统海水淡化工艺难以进一步推广。近年来,太阳能海水淡化作为一种高效低廉的海水淡化技术正逐渐进入人们的视野,其中,太阳能膜蒸馏技术更是凭借着适用范围广、蒸发效率高、能耗低、成本低廉等诸多优点为众多学者所青睐。各国学者从宏观的系统结构到微观的光热材料等方面展开了大量的工作。但由于膜蒸馏固有的温度极化以及膜污染等问题,太阳能膜蒸馏技术仍然处于发展瓶颈中。本文按照太阳能引入膜蒸馏装置位置的不同,对现有的诸多太阳能膜蒸馏系统进行分类,并针对各类太阳能膜蒸馏系统的发展现状和技术瓶颈进行详细阐述。探讨了当前太阳能膜蒸馏技术的局限性及未来的挑战,以期为太阳能膜蒸馏系统的进一步发展及应用提供参考。     

二硫化钼作为海水淡化材料的研究进展

海水淡化是从丰富的海水资源中提取清洁淡水的技术,是解决淡水资源短缺的重要途径。传统的海水淡化技术在实际应用中已经暴露出高成本、高能耗和低效率等缺点,因此开发海水淡化新兴技术及材料成为研究重点。二硫化钼（MoS₂）是典型层状过渡金属硫化物,因其化学稳定、吸光能力优异等优点,在海水淡化领域具有极大的应用前景。作为一种高效环保的海水淡化材料,MoS₂及其复合材料在改善传统脱盐工艺和发展新兴脱盐技术中已得到广泛研究。本文主要论述和分析MoS₂基材料在电容去离子、膜脱盐及太阳能脱盐等海水淡化应用中的研究进展以及在工业化应用中面临的挑战,并展望其今后在脱盐领域的发展方向。     

Membrane processes for water supply and reuse - a question of energy consumption and cost

This paper is limited primarily to reverse osmosis which is the dominating membrane process in commercial plants. Desalination of brackish water and seawater with reverse osmosis, with special emphasis on costs and energy consumption, is the primary subject discussed in the paper. Some aspects of and development trends in industrial and domestic applications of membrane processes are also taken up, particularly with regard to by-product recovery and water reuse in connection with advanced wastewater treatment.The first RO plant to be brought into operation in Riyadh, Saudi Arabia, is located at Salbukh. The investment and total operation costs for this plant have been calculated in the paper. The water cost is at least twice as high as in a continental U.S. location. The main reason for this is the very high cost of civil and local works in Saudi Arabia. A similar calculation has been made for RO seawater desalination.Increased energy costs during the last decade have directed research and development work for all desalination methods towards reducing energy consumption. It is shown in the paper that energy recovery in connection with RO seawater desalination is particularly feasible. Different methods for energy recovery have been investigated and reported, the preferred methods depending on the size of the RO plant. A large underground RO plant for energy recovery, based on utilization of the static pressure instead of high pressure pumps, has also been studied.Another possible energy-saving, but also water quality improving method has been proposed, viz . a combined MSF-RO dual purpose plant. Excess power for reverse osmosis seems to be more and more available in Saudi Arabia due to the high power/water ratio in MSF dual purpose plants compared to the real demand for power and water.     

Performance prediction of hydraulic energy recovery (HER) device with novel mechanics for small-scale SWRO desalination system

The biggest proportion of the cost of desalted water is the energy consumption, especially for small-scale SWRO desalination system. In order to decrease the cost of desalted water, the energy recovery device is preferred to be considered in small-scale SWRO desalination system. However, the investigation of energy recovery device for small-scale SWRO system is scarce. Until now the design of energy recovery device has not been based on the results of the mathematical simulation but almost on experimental and empirical knowledge, and there are few detailed reports about the optimal design of energy recovery device for small-scale SWRO desalination system in previous articles. In the current paper, a hydraulic energy recovery (HER) device with novel mechanics is introduced, the detailed simulation results of the HER device and specific energy consumption of small-scale SWRO system equipped with the HER device are presented. The simulated results are very useful for optimal design of the HER device and its coupling SWRO desalination system.     

压力交换式能量回收器在反渗透海水淡化技术中的应用

在反渗透海水淡化系统中，高压系统中采用压力交换式能量回收器，大大地降低海水淡化的能耗。压力交换式能量回收器的能量回收效率达到95％以上，本文从其工作原理和反渗透海水淡化设计上阐述其应用的优点。     

Theoretical study on multi-effect solar distillation system driven by tidal energy

Based on an analysis of the characteristics of solar and tidal energy, an innovative, multi-effect solar distillation unit for seawater desalination utilizing solar and tidal energy has been developed. The uniqueness of the system is that without being transferred to electricity, tidal energy is utilized to supply power for water supply and drainage, and vacuum extraction instead of pumps powered by electricity. So the cost can be greatly reduced. The system is based on multi-effect evaporation-condensation processes and operates under vacuum condition, so low grade solar heat can be used with a high thermal efficiency. Hydrodynamic and thermal analysis is carried out for the water supply and drainage system driven by tidal energy. The operating mechanism of the vacuum extraction system driven by tidal energy is presented. A parametric study of the behavior of the solar desalination unit has been performed.     

Distillation vs. membrane filtration: overview of process evolutions in seawater desalination

The worldwide need for fresh water requires more and more plants for the treatment of non-conventional water sources. During the last decades, seawater has become an important source of fresh water in many arid regions. The traditional desalination processes [reverse osmosis (RO), multi stage flash (MSF), multi effect distillation (MED), electrodialysis (ED)] have evoluated to reliable and established processes; current research focuses on process improvements in view of a lower cost and a more environmentally friendly operation. This paper provides an overview of recent process improvements in seawater desalination using RO, MSF, MED and ED. Important topics that are discussed include the use of alternative energy sources (wind energy, solar energy, nuclear energy) for RO or distillation processes, and the impact of the different desalination process on the environment; the implementation of hybrid processes in seawater desalination; pretreatment of desalination plants by pressure driven membrane processes (microfiltration, ultrafiltration and nanofiltration) compared to chemical pretreatment; new materials to prevent corrosion in distillation processes; and the prevention of fouling in reverse osmosis units. These improvements contribute to the cost effectiveness of the desalination process, and ensure a sustainable production of drinking water on long terms in regions with limited reserves of fresh water.