我国海水利用工程取水构筑物型式研究

为了明晰不同海水利用工程中经济适用的海水取水构筑物型式,简化海水取水构筑物的选型过程,分类统计了现有海水冷却工程和海水淡化工程的取水流量及所采用的取水构筑物型式,并对取水流量、取水水温、水面波动和水文地质对取水构筑物选型的影响进行了分析.结果 表明,取水流量是决定海水取水构筑物选型的最重要因素.在取水流量范围依次减小的...     

Modeling dispersion of brine waste discharges from a coastal desalination plant

Desalination of seawater leaves brine waste containing a high salt concentration to be disposed of into the environment. For coastal desalination plants, the most practical and least expensive brine disposal operation is to discharge it into the sea. Modeling studies on the effect of coastal water depth variations upon mixing and spreading of brine waste continuously being discharged into the sea are presented. Solutions are illustrated graphically, showing that the brine plumes are spreading downstream and heading towards the beach. For Oman in particular, the increase in salinity in coastal water will intensify the critical problems of seawater intrusion into coastal groundwater aquifers. However, this potential impact of brine disposal operations on coastal and marine environment can be alleviated by building longer sea outfalls.     

Overview of seawater concentrate disposal alternatives

This article discusses the available alternatives for ocean concentrate disposal, site specific factors involved in the selection of the most viable alternative for a given project, and the environmental permitting requirements and studies associated with their implementation. The article focuses on the three most widely used alternatives for ocean discharge of concentrate: direct discharge through new outfall; discharge through existing wastewater treatment plant outfall; and co-disposal with the cooling water of existing coastal power plant. Key advantages, disadvantages, environmental impact issues and possible solutions are presented for each discharge alternative. Results from recent salinity tolerance and toxicity study completed at the Carlsbad, California seawater desalination demonstration plant for a variety of sensitive marine organisms are presented. The practical implementation of this study along with other methods for analysis of the environmental impact of ocean discharges from large seawater reverse osmosis plants is illustrated with case study examples.     

Reverse osmosis desalination plants — marine environmentalist regulator point of view

The environmental characteristics of the brine and its impacts on the marine environment were always the “backyard” and the less concern while planning and operating RO desalination plants. The lack of drinking water in Israel made desalination a national goal. The first huge RO plant was initially operated in Israel on 2005 — 100 Mm³/y and by the end of 2010 305 Mm³/y potable water expected to be produced. Construction and installation of desalination plants requires applying suitable environmental solutions for protecting and preserving the marine and coastal environment from ruin or deterioration.

The Israeli environmental legislation is described including the marine environmental policy and regulations as well as the acquired operational experience during the last two years. Results from the first year of operation and monitoring are shown along with the new appearance of the red phenomenon discharge of VID desalination plant in Ashkelon.

The environmental policy based on the precautionary principle is performed and includes environmental requirements and guidelines for pretreatment, discharge composition, planning marine outfall, background and compliance marine monitoring program and discharge quality standards.     

中国海水淡化工程进展

本文介绍了中国已建成投产海水淡化装置的数量、产量及各种淡化方法所占比例。到目前为止,海水淡化技术主要应用于沿海岛屿和沿海地区电力、化工等企业。随着海水淡化技术的发展和应用规模的扩大,淡化水生产成本将与市政供水价格接近,海水淡化技术将不仅用于沿海岛屿和企业供水,而且将大规模地应用于市政供水。     

海水淡化浓盐水排放对环境的影响与零排放技术研究进展

回顾了目前常用的海水淡化技术及其应用现状,重点综述了海水淡化浓盐水排放对海洋环境的影响,分析了排放盐水的组分、盐度、热污染、腐蚀产物、化学清洗剂等对海洋环境和海洋生物的潜在影响,提出了相应的解决措施与解决方法,说明浓盐水零排放技术是解决环境问题的有效途径。     

Thermoeconomic design of a multi-effect evaporation mechanical vapor compression (MEE–MVC) desalination process

Desalination of seawater accounts for a worldwide water production of 24.5 million m³/day. A “hot spot” of intense desalination activity has always been the Arabian Gulf, but other regional centers of activity emerge and become more prominent, such as the Mediterranean Sea and the Red Sea, or the coastal waters of California, China and Australia. Despite the many benefits the technology has to offer, concerns rise over potential negative impacts on the environment. Key issues are the concentrate and chemical discharges to the marine environment, the emissions of air pollutants and the energy demand of the processes. To safeguard a sustainable use of desalination technology, the impacts of each major desalination project should be investigated and mitigated by means of a project- and location-specific environmental impact assessment (EIA) study, while the benefits and impacts of different water supply options should be balanced on the scale of regional management plans. In this context, our paper intends to present an overview on present seawater desalination capacities by region, a synopsis of the key environmental concerns of desalination, including ways of mitigating the impacts of desalination on the environment, and of avoiding some of the dangers of the environment to desalination.     

Seawater desalination and reverse osmosis plant design

Plant site, water intake, pretreatment, choice of materials of construction, design alternatives and energy recovery are important variables to be considered in the design of seawater desalination plants employing “permasep” B-10 reverse osmosis modules. Techniques are outlined to permit custom design of seawater desalination plants which offer reliable long term performance as well as competitive economics.     

Influence of desalination effluents on marine ecosystems

Water, re-entering a marine ecosystem after transit through a desalination plant, may be altered in three major ways. One, its thermal energy may be increased; two, its chemical make up may be altered; and three, its microbial biota may be modified. The effect of thermal enrichment on natural marine ecosystems varies with the change in temperature, the duration of that temperature change, and its geographical extent. If the desalination plant is sited in such a manner so as to allow rapid dissipation of the thermal input, the effect of the temperature change will be minimized. Signs of thermal effect on marine ecosystems could be manifested by changes in community structure (types of organisms), as well as the changes in features of individual species. The most obvious chemical changes in desalination effluents may include increase in salinity, a decrease in dissolved oxygen, an increase in dissolved organics, and an increase in pretreatment chemicals. As with thermal input, the effect of these chemical changes in the effluent on natural ecosystem will depend upon the rate of entrance and dispersion. As the rate of dispersion is increased, the effect of chemical changes on ecosystems is correspondingly decreased. Desalination plants, due to their design, provide surface areas for rapid microbial proliferation. Depending upon the sequence of chemical pretreatment, it is possible that these viable microbes will enter the ecosystem and supplement the existing biota, if conditions permit their continued growth.The environmental impact in several types of desalination plants (distillation and reverse osmosis) on natural marine ecosystems will be discussed. The problems imposed on the environment by these desalination plants will be presented and similarities to problems encountered in other types of condenser-heat exchanger systems (Power plants and ocean thermal energy converters) will be analyzed.     

Performance study of water desalination methods in Saudi Arabia

Saudi Arabia is an arid desert country without rivers or sweet water lakes, however, it does have vast amount of groundwater and seawater. In order to make these waters suitable for human consumption and industrial use, most of their salts must be removed by some means. The desalination methods most frequently used in the Kingdom are: Multistage flash (MSF) evaporation, reverse osmosis (RO), and electrodialysis (ED).During the last decade, we have witnessed a spectacular growth of desalination plants. This growth is expected to continue in the next decade. The present production capacity of all desalting plants in Saudi Arabia is estimated to be 750,000 m³/day; this figure will be most likely tripled in the next five years.This paper is a report on a performance study of the most significant desalination plants in the Kingdom. The plants, which include MSF and seawater and brackish water RO plants, were selected either because of their size or their importance to the desalination technology. The plants are briefly described and their performances are discussed.     

浓海水处理及综合利用技术的新进展

对海水淡化过程产生的浓海水进行再脱盐,可进一步提高淡水回收率,并有效避免优质化学资源的浪费和对海洋生态环境的污染。本文介绍了多效蒸馏、共晶冷冻结晶、电渗析、膜蒸馏、膜结晶等浓海水再脱盐技术的原理、特点、应用实例和新进展,并对比分析了各种技术的优势和存在的不足,对基于多种热膜集成过程的浓海水“零排放”和综合利用技术进展作了重点讨论。最后指出,除相对成熟的多效蒸馏法和电渗析法外,其他多数浓海水再脱盐技术仍处于实验研究阶段,将反渗透与可再生能源驱动的膜蒸馏技术进行耦合发展高效盐化工将是浓海水处理领域的重要方向。     

The Libyan experimental on the environmental impact assessment for desalination plants

The desalination industries are considered to have a major role in developing human life. Recently this technology became widely distributed, and its construction along the coastal area has been widely reported. Many countries are adopting these technologies for securing the fresh water supply for consumer consumption all over the world. This situation has raised the need for researches to evaluate the environmental impact assessment (EIA) of these technologies on coastal line environment.

This study has been directed to monitor sea water quality used for feeding desalination plants to determine the concentrates of selected pollutants such as heavy metals by using chemical monitoring system to know their effects on the desalination units and other components. This study was conducted in the year 2003 from January to June. Samples were collected from feed water intake of Benghazi North desalination plant and Tobrouk desalination plant, both plants were chosen because of their importance for supplying fresh water for potable water and industrial uses.

The results of this study showed monthly differences in most tested parameters, these differences lead to the scale and corrosion by precipitation on the components of the desalination unites. The objectives of this study is to know the main reasons which caused increasing these concentrates in the sea water (study area) and know how to deal with.     

Development of environmental standards for combined desalination/power generating stations in the Arabian Gulf region

Environmental effects associated with desalination/power generation are classified into intake and discharge components. The intake component consists of entrainment and impingement problems while the discharge component comprises chemical and physical problems associated with the receiving waterbody. Each component is discussed relative to marine communities in the receiving waterbody and a methodology is presented for establishing an environmental managenent policy which will protect these communities.     

Integration of seawater desalination with power generation

The economic benefits of integrating seawater desalination with power plants are discussed, starting from the first principles of thermodynamics. The concepts of the “fuel-use performance ratio” and the “power loss” method are described in the context of their usage for thermal cycle evaluation and desalination process selection, both with conventional steam cycles and with combined cycle power plants. A thermo-economic model is introduced to evaluate water and power costs and rates of return in dual-purpose power/desalination applications. The future of integrated power and desalination plants is discussed with reference to the growing role of seawater reverse osmosis (SWRO) in the desalination arena. A case study is presented to evaluate the benefits of integrating SWRO with existing power/desalination plants in the Middle East. Subject to the assumptions of the study, it is concluded that repowering and retrofitting would result in a nearly three-fold increase in the power generating capacity and an over six-fold increase in the water output, without requiring any expansion of the seawater intake system. Based on natural gas fuel, the repowered plant would also result in a 70% increase in the fuel efficiency of the station and a drastic reduction in the cost of water production. For a privatization scenario, an economic analysis is used to show that attractive rates of return would be obtained if a developer were to purchase and refurbish the existing plant, selling the products on a build own and operate (BOO) basis. In preparation for this promising application, the need for pilot plant testing at existing power/desalination stations, together with research and development work in membrane technology for high temperature operation, is emphasized.     

华能玉环电厂海水淡化工程设计概述

华能玉环电厂的淡水系统全部采用了世界先进的“双膜法”海水淡化技术,工程投资约2亿元,计划2006年4月30日制出合格的淡水。本文以华能玉环电厂海水淡化工程实例为基础,根据国内外海水淡化发展的新技术以及经验,分析对比了高压泵的选型、能量回收装置的特点,以及回收率确定的几项因素,并根据工程情况分析了制水成本。对缺乏淡水的沿海电厂来说采用海水淡化无疑是一种非常好的选择方案。     

Myth and reality of the hybrid desalination process

The paper discusses some misconceptions that have contributed to the continued use of thermal desalination processes and promotion of the hybrid desalination process for new plants being built or considered at Middle East locations. The misconceptions are examined both on the basis of fundamental thermodynamic principles and in terms of practical engineering parameters. The analysis shows that there is no economic or performance advantage in the installation of greenfield hybrid power/thermal desalination/ seawater reverse osmosis (SWRO) plants in preference to power/SWRO plants, because the latter would produce water more cheaply under all conditions and at all fuel costs, and would provide more operational flexibility than the former. The paper identifies situations where the hybrid desalination process can be fully justified: in existing power/desalination plants, where aging boilers and multistage flash (MSF) units need to be repaired or replaced, through retrofitting and repowering. In such situations, abandonment of the MSF process would result in a reduction in the power output of the plant. The paper refers to previous work which showed that the repowering of a typical existing power/desalination station with refurbishment/replacement of the MSF units, together with the addition of SWRO units, would result in a several-fold increase in the water and power output and a dramatic improvement in the fuel efficiency, without any additions to the existing seawater intake system. The paper emphasizes the importance of test stations/demonstration plants at existing power/desalination stations in the Middle East in order to obtain data and make improvements in the technology of higher temperature SWRO, with the feed obtained from the cooling water returning from the power plant condenser and the thermal desalination plant. The paper shows that the potential benefits would easily justify the investment in research and development required to validate this concept.     

船用集成膜海水淡化装置的设计

提出了集成膜工艺技术应用于船用海水淡化装置,并总结出完整的膜法预处理技术、隔振技术、自动化控制技术设计方法.采用可靠性设计技术,使装置更适合船用化条件,以保证装置性能稳定可靠.     

PV‐betriebene Umkehrosmoseanlage zur Meerwasserentsalzung – Modellierung und Analyse verschiedener Energieversorgungsvarianten

Reverse osmosis is a very energy‐efficient approach for seawater desalination. Since it requires only electrical energy, a combination of reverse osmosis and photovoltaic (PV) plants seems to be a promising solution. Therefore, a PV‐based reverse osmosis plant for seawater desalination for a location in Saudi Arabia is designed and modeled. On this basis, different options of a PV‐powered seawater desalination plant are investigated and conclusions for the construction of such plants are derived.     

Simulation and Analysis of a Single‐Effect Thermal Vapor‐Compression Desalination System at Variable Operation Conditions

A mathematical model is developed to analyze a single‐effect thermal vapor compression (TVC) desalination system. The effects of the variation of operation conditions such as the intake seawater temperature and the mass flow rate of cooling water on the system performance are investigated for a specific desalination unit. The system performance is found to decrease when the intake seawater temperature is different from the design value. By adjusting the mass flow rate of cooling water, a better system performance can be obtained when the intake seawater temperature differs from the design conditions. Decreasing the cooling water flow rate to values lower than the design value can lead to a better performance when the intake seawater temperature is lower than the design value, and the system performance reaches a peak point when the cooling water flow rate decreases to a definite level. A better performance can also be obtained by increasing the cooling water flow rate to values higher than design value, when the intake seawater temperature is higher than the design value and the system performance also reaches a peak point when the cooling water flow rate increases to a definite level.     

沿海挡潮闸焦油无机涂料防腐处理

分析了沿海挡潮钢闸门长期受浸泡海水、干湿交替、日光曝晒、沿海盐雾、海生生物及潮湿空气的腐蚀情况。采用焦油无机涂料对挡潮闸进行防腐处理，介绍了预处理及涂装过程，经5年使用后，漆膜完好无损。