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。     

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%。     

海水反渗透淡化用带流体切换器的能量回收设备

Energy recovery device （ERD） is an important part of the seawater reverse osmosis （SWRO） desalination system. There are principally two kinds of ERDs, the centrifugal type and the positive displacement （PD） type. The PD type is of extensive concern and is preferred in large-scale plants. In this article, an innovative fluid switcher was presented and a two-cylinder hydraulic energy recovery unit with a lab-scale fluid switcher was set up. Tap water was used as the working medium instead of the actual seawater and brine in SWRO desalination plants. Under steady state operating conditions, the experimental results were obtained on the variations of the pressure and flow rate to and from the energy recovery unit. The hydraulic recovery efficiency （En） of the energy recovery unit with the fluid switcher reached up to 76.83%.     

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。     

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。     

海水淡化的现状与未来

本文介绍了近来主要海水淡化方法－ＳＷＲＯ、ＭＳＦ、ＭＥＤ的某些新进展。海水淡化市场的激烈竞争和海水淡化技术进步,尤其是ＳＷＲＯ的进展,使淡化的能耗下降了近一半,产水的出厂价也几乎下降了一半。     

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%。     

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...     

A comparison of the relative economics of sea water desalination by vapour compression and reverse osmosis for small to medium capacity plants

Lowest energy consumption is not necessarily the determining criterion for lowest cost sea water desalination. It is shown that at present-day market prices for plants, electrical energy and fuel oil, Vapour Compression plants with horizontal aluminium tubes—the “Ambient Temperature” Vapour Compression (ATVC)system—compares economically with Sea Water Reverse Osmosis (SWRO) even at the lowest net energy consumption achieved by the latter process by the use of high efficiency energy recovery turbines. This economic parity is shown to apply for plants of up to 4000 m³/day (1 mgd), and is shown to be maintained for future foreseeable developments resulting in reduced energy consumptions and more efficient plants.It is also indicated that more areas for potential improvements are available for ATVC, than for SWRO, which may result in more favorable economics for the former process in the future.     

旋转式能量回收装置的启动与运行特性

能量回收装置是降低反渗透海水淡化（SWRO）系统运行能耗和制水成本的关键设备之一。本文开发并试制了一种具有新型端盘结构的旋转式能量回收装置,并对其启动方式进行了研究优化,测试分析了装置的动密封性能和效率特性,并对装置连续运行稳定性进行了考核。结果表明,旋转式能量回收装置在转速增至额定值后再进行升压操作的启动方式下驱动扭矩最小;装置泄漏量随操作压力增高而增大,在6.0 MPa时,为0.58 m3/h;在转速为500 r/min、处理量为8.0 m3/h及操作压力为6.0 MPa时,装置连续运行稳定,能量回收效率为93%。这些研究结果对旋转式能量回收装置的开发和工程应用具有一定的指导意义。     

On the reduction of desalting energy and its cost in Kuwait

All seawater desalting processes, multi-stage flash (MSF), multi-effect boiling (MEB), mechanical vapor compression (MVC) and seawater reverse osmosis (SWRO) consume significant amounts of energy. The recent increase of fuel oil cost raises the cost of energy consumed for desalting water and the final water cost, and creates more interest in using more energy efficient desalting systems.

The most used desalting systems by distillation (MSF and MEB) are usually combined with power plants in what is called co-generation power desalting plants, CPDP. Fuel is supplied to the CPDP to produce both desalted water D and power W, and the fuel cost is shared between D and W. Exergy analysis and equivalent work are among the methods used to determine the fuel energy charged to each product. When desalting systems, such as SWRO and MVC, are not combined with a power plant, the fuel energy can be directly determined from its electrical power consumption.

In this paper, the fuel energy cost charged to desalting seawater in the presently used CPDP in Kuwait is calculated based on exergy analysis. The MSF, known by its high energy consumption, is the only desalting method used in Kuwait. The MSF units consume 258 kJ/kg thermal energy by steam supplied to the brine heater BH, 16 kJ/kg by steam supplied to steam ejectors, and 4 kWh/m3 mechanical energy for pumping. These MSF units are operated either by:

(1) Steam extracted from extraction/condensing steam turbines EC/ST as in as in Doha West, Azzour, and Sabbiya CPDP. This practice is used in most Gulf area.

(2) Steam supplied directly from boilers as occurred in single purpose desalting plants as Al Shuwaikh plant; or in winter time when no steam turbines are in operation in the CPDP to supply steam to the desalting units.

The CPDP have limited water to power production ratio. While they can cope with the increase of power demand, it cannot satisfy the water demand, which is increasing with higher pace than the power demand.

The case of steam CPDP used in Kuwait is presented in this paper as a reference plant to evaluate the amount of fuel energy consumed to desalt water in MJ/m3, its cost in $/m3. The resulted high fuel cost calls for some modifications in the reference CPDP to lower the energy cost, and to increase its water to power ratio. The modifications include the use of an auxiliary back-pressure steam turbine ABPST supplied with the steam presently extracted to the MSF units. The power output of the ABPST operates MVC or SWRO desalting units; while the ABPST discharged steam operates LT-MEB desalting unit. The desalting fuel energy costs when applying these modifications are also calculated by the exergy analysis and compared with that present situation.

It is also suggested to increase desalted water output by using separate SWRO desalting units operated by the existing power plants of typical η_c = 0.388, or by new combined gas/steam turbines power cycle GT/ST-CC of typical η_c = 0.54 under construction. The SWRO with energy recovery is assumed to consume typical 5.2 kWh/m³ electric energy.     

海岛一体化制水装置研究与应用示范

2009年10月,在洞头县大瞿岛村建成一套50m~3·d~(-1),海岛一体化制水装置,该装置采用先进的反渗透技术、能量回收技术、微电解技术,电抑菌技术,产水水质好,能耗省,制水成本低,占地面积少.本装置的应用示范打破了国外公司对海水淡化能量回收装置的垄断,对海岛地区降低海水淡化工程建设成本、降低制水能耗、提高产品水的水质以及降低设备运行维护费用等方面起到较好的示范推广作用,对缓解我国的海岛及部分沿海地区村庄的水资源危机和保障我国海水淡化的供水安全具有极为重大的意义.     

Fresh water by reverse osmosis based desalination: simulation and optimisation

The reverse osmosis (RO) desalination process to make fresh water from seawater has been studied here. First, a model for the process is developed. Sensitivity of different operating parameters (feed flow rate, feed pressure) and design parameters (internal diameter, total number of tubes) on the recovery ratio are studied via repetitive simulation. Finally, an optimisation framework for the process is developed so as to maximize the recovery ratio or a profit function using different energy recovery devices, subjectto general constraints. The optimal operating parameters (feed flow rate, feed pressure) and design parameters (internal diameter, total number of tubes) are determined by solving the optimisation problem using an efficient successive quadratic programming (SQP) based method. The optimal values for the decision variables depend on the constraints introduced, and are also sensitive to variations in water and energy prices, as well as feed concentration. The use ofthe emerging energy recovery devices is widely justified, reporting much higher reductions in operating costs than the traditional technology used for this purpose. Using a pressure exchanger device, it is possible to reduce energy consumption by up to 50%.     

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.     

反电渗析法海水淡化副产浓水盐差能利用

海水淡化是解决淡水资源短缺的有效途径,其副产的浓海水具有较高的浓度,而基于离子交换膜的反电渗析（RED）法发电是对盐差能利用的有效手段。通过模拟计算研究了以反渗透法海水淡化副产的浓水和海水为进料的情况下,RED装置发电的功率密度和能量效率,并探讨了多级操作对于RED系统功率密度和能量效率的影响。结果表明：单级RED的发电功率密度随水回收率的提高和隔板厚度的降低而增大,但过程的能量效率均低于30%。RED多级操作能显著提高系统的能量效率。探讨了影响淡化浓海水盐差能利用效果的因素,并提出多级RED作为提高浓水盐差能利用效率的手段,研究结果为海水淡化副产浓水的利用提供了一种新的思路。     

Design, simulation and economic analysis of a stand-alone reverse osmosis desalination unit powered by wind turbines and photovoltaics

The fresh water shortage is a significant problem in many areas of the world such as deserts, rural areas, Mediterranean countries and islands. However, renewable energy potential in these areas is usually high using solar and wind energy. A desalination unit powered by renewable energy sources is a promising solution for this problem. This paper presents the design of a stand-alone hybrid wind-PV system to power a seawater reverse osmosis desalination unit, with energy recovery using a simplified spreadsheet model. A daily and monthly simulation and economic analysis were also performed. The calculated fresh water production cost was 5.2 ?/m³, and the realized energy saving was up to 48% when a pressure-exchanger-type energy recovery unit is considered.     

Energy and water in Kuwait: A sustainability viewpoint, Part II

In Kuwait, the daily consumption per capita of electric power is 14,000 kWh, and of desalted water is 600 L. These are among the highest in the world, and the total consumption of each is almost doubled every 10 years. The cogeneration power desalting plants CPDP producing these two commodities consumed about 54% of the total 150 millions barrels of fuel consumed in the year 2005. If these consumption and production patterns prevail, the fuel oil produced in the country can be fully consumed locally in 30 years, with nothing left for export, the main source of income. The picture can be changed if better desalted water and power production methods are used. These include changing the desalting method from multistage flash MSF known by its high energy consumption to the more energy efficient seawater reverse osmosis SWRO; and power production method of steam or gas turbine cycles to combined gas/steam turbine combined cycle known of its high efficiency. The energy consumed by the air conditioning AC systems should be reduced by using better codes of building insulation and more efficient AC systems. Other conservation methods to reduce water consumption and the energy consumed by transportation are outlined in this paper.     

海水反渗透脱盐装置水压能量回收

1 INTRODUCTION Since the 1980s,turbine type energy recovery devices have been used in Sea Water Reverse Osmosis(SWRO) desalination plants in a dominant position.     

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.     

Design and optimization of seawater reverse osmosis desalination plants using special simulation software

This paper introduces the Integrated process simulation environment (IPSEpro™) software, and its application to reverse osmosis desalination.The paper introduces the reader to the basic modeling concepts, and how individual process units can be simply simulated with a graphical, flowsheet style interface.The paper then goes on to describe an example simulation for off design of an integrated pump, membrane rack and isobaric energy recovery device, investigating the effects of changing water quality, membrane condition and also, the influence of isobaric energy recovery device overflush.