长岛1000吨/日反渗透海水淡化示范工程

长岛1000t／d反渗透海水淡化工程是我国第一个自行设计、建造的日产千吨级反渗透海水淡化示范工程,在国内首次使用压力交换式能量回收设备,建成后运行正常,能耗达到国际先进水平,为推广我国的海水淡化起到了很好的示范作用。     

正位移式阀控能量回收装置盐水连续进料过程特性研究

能量回收装置是反渗透海水淡化系统的关键设备之一，对降低系统运行能耗和造水成本至关重要。正位移式阀控能量回收装置以反渗透淡化系统排放的高压盐水作为进料，通过在水压缸中直接增压原料海水的方式来实现压力能回收利用。但在装置运行过程中常常存在高压盐水进料不连续（即流量有较大波动）等问题，直接影响了反渗透淡化系统运行的稳定性。本丈在分析造成上述问题原因的基础上，通过改进控制方案，使得高压盐水进料过程中的流量和压力波动问题得到有效解决，保证了盐水进料的连续性。针对阀控能量回收装置运行过程中低压进料海水仍存在流量和压力波动的现象，文章提出了两个具体的措施，即通过多套装置并联运行及在进料海水管路上设置旁路的方式来解决。     

膜法海水淡化系统在华能威海电厂的应用

随着我国水资源的日益匮乏,海水淡化技术不断应用于工业中。华能威海电厂三期海水淡化系统设备为笔者所在公司提供,海水作为该厂锅炉补给水水源,采用了超滤(UF)-海水反渗透(SWRO)-一级反渗透-二级反渗透-电去离子技术(EDI)全膜法制备。其中能量回收作为海水淡化系统的重要部分,本文将介绍几种常用的能量回收装置,并详细介绍膜法海水淡化系统在该厂中的应用。     

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。     

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。     

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.     

反渗透海水淡化技术在舰船上的应用

海水淡化是维持舰船所需淡水供应和补充的唯一途径。阐述了反渗透海水淡化技术在反渗透膜、预处理和能量回收装置等关键技术上的发展,介绍了反渗透海水淡化技术在舰船上的应用。     

外驱旋转式能量回收装置的设计和性能测试

旋转式能量回收装置（RERD）作为反渗透海水淡化系统的节能设备,对于降低系统能耗和产水成本具有重要意义。设计和加工了一套新的外驱旋转式能量回收装置,建立了满足其性能评测要求的一套完整的反渗透海水淡化系统。当装置的性能很好地满足工业化运用需求时,对RERD与反渗透淡化系统的耦合运行性能进行了现场测试。实验结果表明：反渗透膜的操作压力为6.0 MPa、RERD的处理量为13 m³/h及转子转速为500 r/min时,装置的泄漏量为0.57 m³/h,能量回收效率达到91.2%。保持反渗透膜的操作压力和装置转速不变,当装置的处理量为16 m³/h时,进出RERD的4股流体的流量和压力波动较小,装置的能量回收效率略有提高,达到92.5%。     

反渗透海水淡化技术研究进展

反渗透海水淡化技术以其特有的优点得到了越来越广泛的应用,近几十年来我国对该技术的研究取得了较大发展。该文综述了反渗透海水淡化技术的发展过程及应用状况,重点介绍了反渗透膜、预处理技术、能量回收技术、反渗透系统优化设计等方面的技术进步及存在的问题,根据该技术研究及应用现状,提出了我国反渗透海水淡化技术未来发展的看法。     

基于AMESim的海水淡化斜盘柱塞式能量回收装置运行性能分析

为满足中小型海水淡化系统节能降耗需求,设计开发了一种新型斜盘柱塞式能量回收装置,并基于AMESim仿真分析软件构建了斜盘柱塞式能量回收装置的液压仿真模型及与之配套的反渗透海水淡化系统流体计算模型,对斜盘柱塞式能量回收装置在海水淡化系统中的耦合运行性能进行了模拟研究.结果 表明:在装置高压进流压力为6.0 MPa,设计处...     

Hybrid Reverse Osmosis‐Capacitive Deionization versus Two‐Stage Reverse Osmosis: A Comparative Analysis

Reverse osmosis (RO) is a high‐pressure single‐phase desalination process used to obtain freshwater from seawater/brackish water. The RO system shows high energy consumption for a given unit volume of pure water produced. The reported hybrid system of RO and capacitive deionization (CDI) aims at improving the RO water recovery and minimizing energy consumption. The RO‐CDI system is simulated and compared with two‐stage RO, to determine the effectiveness of the new hybrid system. The energy recovery from RO brine was also studied. The specific energy consumption by two‐stage RO for two different arrangements of the energy recovery device is higher than for RO‐CDI. The hybrid RO‐CDI system is energy efficient for the production of freshwater from brackish water.     

反渗透-离子交换联合除盐系统的选择

通过在工程设计实践中,对受海水倒灌水源反渗透系统段间增压泵的研究,提出的设置其意义可减少在水源不受成潮影响时的第一段膜组件的进口压力及能耗,其也可用于已有的苦咸水淡化系统的工艺改造．从而提高第二段膜堆的产水量(约25％)或降低系统的能量消耗。此外．对后续除咸系统的选择．提出了可供选择的方案。     

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.     

An autonomous wave-powered desalination system

The potential for an autonomous wave-powered desalination system is considered and it is identified that the most promising configuration is a reverse osmosis (RO) plant utilising a pressure exchanger-intensifier for energy recovery. A numerical model of the RO plant with a pressure exchanger-intensifier is developed that shows that a specific energy consumption of less than 2.0 kW h/m³ over a wide range of sea-water feed conditions, making it particularly suitable for use with a variable power source such as wave energy. A numerical model of the combined wave-power and desalination plant is also developed that shows that it is possible to supply the desalination plant with sea-water directly pressurised by the wave energy converter, eliminating the cost and energy losses associated with converting the energy into electricity and back to pressurised water. For a typical sea-state the specific hydraulic energy consumption of the desalination plant is estimated to be 1.85 kW h/m³ whilst maintaining a recovery-ratio of less than 25 to 35% to avoid the need for chemical pre-treatment to eliminate scaling problems. It is suggested that the economic potential for wave-powered desalination depends on these energy and cost savings more than compensating for the reduction in membrane life that occurs with variable feed conditions.     

变负荷反渗透海水淡化技术研究

为适应风电、太阳能等新能源的波动性,设计了可变负荷的反渗透(RO)海水淡化装置,用电动阀替代常规浓水调节阀,变频器控制高压泵电机,通过PLC控制变频器的输出频率和电动阀的开度使RO海水淡化的功率可调;利用溶解扩散模型分析了变负荷海水淡化的特性,并通过试验验证了相关结论。在维持膜壳内压力稳定的工况下,低功率运行时可以增加系统回收率,降低单位产水能耗,可以降低运行成本。     

Effect of Stream Mixing on RO Energy Cost Minimization

Various mixing operations between the feed, retentate and permeate streams are studied in this work to determine their effectiveness in decreasing the specific energy consumption (SEC) of single-stage (single-pass), two-pass and two-stage reverse osmosis (RO) processes operated at the limit of the thermodynamic restriction. The results show that in a single-stage RO process, partial retentate recycling to the feed stream does not change the SEC, while partial permeate recycling to the feed stream increases the SEC if targeting the same overall water recovery. Energy optimization of two-pass membrane desalination, with second-pass retentate recycling to the first-pass feed stream and operated at the limit imposed by the thermodynamic restriction, revealed the existence of a critical water recovery. When desalting is accomplished at recoveries above the critical water recovery, two-pass desalination with recycling is always less efficient than single-pass desalination. When desalting is accomplished at recoveries below the critical water recovery, an operational sub-domain exists in which the SEC for a two-pass process with recycling can be lower than for a single-pass counterpart, when the latter is not operated at its globally optimal state. For the two-stage RO process, diverting part of the raw feed to the second stage, in order to dilute the feed to the second-stage RO, does not decrease the minimal achievable SEC of a two-stage RO process. The various mixing approaches, while may provide certain operational or system design advantages (e.g., with respect to achieving target salt rejection for certain solutes or flux balancing), do not provide an advantage from an energy usage perspective.     

Sustainable fuel cell integrated membrane desalination systems

According to the United Nations, between two and seven billion people will face water shortages by the year 2050. Further, it is estimated that the amount of water available per person will shrink by a third during the next two decades. Inadequate supply of good-quality water coupled with higher water demand due to rapid population growth and industrialisation in developing countries are among the major reasons for the worsening water situation. Current shortages of potable water around the world and looming water scarcity especially in the developing countries is the driving force behind the implementation of membrane technologies for seawater and brackish water desalination. Typical energy consumption in seawater reverse osmosis (RO) plants operating at 40–45% product water recovery and with energy recovery from the high pressure reject stream currently is about 3–4 kWh/m³. The near-term goal of the industry is to reduce energy consumption to less than 2 kWh/m³ by using a combination of energy efficient RO pumps, more efficient energy recovery devices, high performance low energy RO membranes, hybrid membrane systems, advanced pretreatment technologies and alternate energy integrated membrane systems. The beneficial aspects of using alternate energy systems such as on-site distributed fuel cell systems integrated with membrane desalination units in remote locations are discussed.     

Sea water desalination by reverse osmosis in chigasaki laboratory

For the purpose of constructing a reverse osmosis [RO) sea water desalination plant of 800 m³/day capacity, a series of tests on the following themes have been carried out in the Chigasaki Laboratory:

1. Performance and durability of 8B modules made in Japan

2. Simplification of pretreatment system

3. Establishment of energy recovery system.

Domestic modules showed good and stable performance during long term operation, and water recovery ratio of these modules have been raised to 40%.

In-line coagulation and filtration system has been established for the pretreatment of feed sea water, instead of coagulation, sedimentation and filtration system.

The energy recovery equipment is consisted of a high-pressure pump, a motor and a hydraulic turbine on a common base. Recovered energy from pressurized brine is used for the auxiliary motive power of the high-pressure pump. The experimental data show that about 20% of required power for the pump was recovered.     

高回收率反渗透海水淡化工艺

目前反渗透海水淡化的回收率小于40％。本文研究开发死端超滤预处理技术和反渗透一纳滤联合脱盐相结合的膜集成海水淡化新工艺,与传统工艺比较,具有装置体积小,产水回收率高等优点。文章介绍了采用新工艺的海水淡化装置样机的试制情况及现场运行结果。沿岸海水为料液,操作压力1为5．1MPa条件下,操作压力2为2.0MPa条件下,装置脱盐率99．21％,产水量3971.3L/h,产水回收率55％。海水淡化装置对海水中Ca^2 、Mg^2 、Na^ 、HCO3^-、Cl^-、SO4^2-、TDS,总碱度,总硬度的脱除率分别为99％,99．6％,99．21％,95％,99．35％,98．48％,99.21％,95％,99．42％。