THE INFLUENCE OF RESIDUAL STRESS ON THE CORROSION RESISTANCE OF H68A BRASS TUBES IN SEA WATER

This paper reveals the morphological characteristics of the cracks formed in H68A brass tubes fully immersed in seawater, and studies the depth profiles of the residual stress of the tubes. Tbe great residual stress in the wall results in stress-corrosion cracking, and the unique morphology of the cracks is due to the uneven distribution of residual stress through the depth of the tube.     

钢质海水管道系统外加电流阴极保护的应用与探讨

根据外加电流阴极保护技术在某钢质海水循环水管道系统中的应用情况，结合理论及实践经验，提出了海水管道系统外加电流阴极保护的设计原则，以及应用中存在的问题，对这些带有普遍性的问题进行了探讨。有关的观点和经验可供应用参考。     

Performance of a seawater desalination system coupled with a nuclear heating reactor under off-design operating conditions

In order to understand the performance of a large-capacity VTE-MED nuclear seawater desalination system thoroughly, the responding characteristics of the system to the off-design operating conditions were studied. The influence of scale deposit in tubes on the heat transfer areas needed and on the heat transfer coefficients with high top boiling temperature (TBT) was illustrated. The decrease of GOR, and also the damage to the normal operation of the system caused by temperature drop of feed brine because of seasonal variation, were explored, based on which a corresponding approach for adjusting feed brine flow rate was proposed. An optimal brine feed flow rate was also proposed to obtain the highest GOR under different heat loadings. The work could be helpful for the efficient and safe operation of nuclear VTE-MED desalination plants.     

温度的变化对海水电解阳极过程的影响

主要讨论海水温度的变化对海水电解用阳极过程的影响。温度升高，析氯电位和阳极电极电位降低，有利于氯气的析出。但同时温度升高，氯气在海水中的溶解度降低，次氯酸盐的分解加剧，从而导致阳极电流效率下降，电解的直流电耗上升。     

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.     

Anti-Biofouling Ozone System for Cooling Water Circuits. II – An Application To Seawater

A new anti-biofouling ozone system which intermittently supplies high-concentration ozone was demonstrated to be effective for preventing marine biofouling in test cooling tubes (titanium, aluminum brass and epoxy-coated PVC) simulating condenser and intake conduit systems of power plants. Injection of ozone of about 5 mg/L for five minutes once each day was enough to keep them clean. Corrosion of titanium and aluminum brass tubes after the three-month test was found tobe negligible.     

Modelling of flash and stripping phenomena in deaerators for seawater desalination

In this paper deaeration efficiency is studied and discussed with regard to a seawater desalination plant under construction in Ruwais (United Arab Emirates) for ADNOC (Abu Dhabi National Oil Company). In particular, a modelling activity has been performed in order to optimise deareator design. Seawater flashing and stripping have been investigated, and a simulation code has been set up taking account of mass, energy and momentum balances together with phase equilibrium conditions. Parametric studies have been carried out analysing the effects of seawater and stripping steam flow rates, as well as those of temperature, pressure, packing height and other operating conditions or deaerator geometrical characteristics. Different models have been discussed interpreting flash and stripping phenomena; and in the light of the results obtained, here shown and discussed, new solutions have been proposed to reduce the costs of the deaerator installation and management.     

高压可视化天然气水合物实验装置的研究

对高压可视化天然气水合物实验装置进行了研究.实验装置以现有天然气水合物开采方法结合水合物法海水淡化技术为研究背景,模拟海洋环境;利用水合物技术原位制备热盐水,开采海洋天然气水合物;采用可视化技术,可观察到水合物晶体状态.实际应用表明,该装置达到了设计效果,同时还可以应用到海水淡化等领域.     

Corrosive Wear Performance of Monel K500 Alloy in Artificial Seawater

In corrosive wear, one of the most interesting phenomena is the synergism where both corrosion and wear are significantly increased, leading to much greater material losses than produced by the sum of material losses by either process alone. A systematic investigation was carried out in the present work to assess the electrochemical and corrosive wear behaviors of Monel K500 alloy sliding against alumina in artificial seawater using a pin-on-ring tribometer integrated with a potentiostat for electrochemical control. The open circuit potential clearly shifted to the cathodic direction due to sliding action. The corrosion current density was much higher under sliding than under corrosion only. Moreover, high normal load and rotation speed result in low open circuit potential and high corrosion current density. The material loss was greater under open circuit potential than under cathodic protection. Corrosion induced an increase in material loss. The material loss caused by a synergistic effect between corrosion and wear contributed to about 20% of the total material loss. The synergistic effect can be divided into wear-induced corrosion and corrosion-induced wear. Wear-induced corrosion was caused by damage to the passive film due to the sliding action of the counterbody, leading to accelerated dissolution. Corrosion can promote the growth and propagation of microcracks in the wear track, which causes corrosion-induced wear.     

Water desalination systems powered by renewable energy sources: Review

Water and energy are two of the most important topics on the international environment and development agenda. The social and economic health of the modern world depends on sustainable supply of both energy and water. Many areas worldwide that suffer from fresh water shortage are increasingly dependent on desalination as a highly reliable and non-conventional source of fresh water. So, desalination market has greatly expanded in recent decades and expected to continue in the coming years. The integration of renewable energy resources in desalination and water purification is becoming increasingly attractive. This is justified by the fact that areas of fresh water shortages have plenty of solar energy and these technologies have low operating and maintenance costs.The present paper presents a review for the work that has been achieved during the recent years in the field of desalination by renewable energies, with emphasis on technologies and economics. The review also includes water sources, demand, availability of potable water and purification methods. A comparative study between different renewable energy technologies powered desalination systems as well as performance and economics have been done. Finally, some general guidelines are given for selection of desalination and renewable energy systems and the parameters that need to be considered.