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33.
Robert E. Melchers 《Corrosion Science》2005,47(10):2391-2410
34.
金属在海水中的腐蚀电位研究 总被引:20,自引:3,他引:20
获得了38种金属在天然海水中浸泡180d的腐蚀电位数据,列出了它们在海水中的腐蚀电位序,讨论了金属材料在海水中的腐蚀电位特性,分析了它们在海水中的腐蚀电位与耐蚀性的关系。结果表明,钝化能力强的金属,其腐蚀电位随浸泡时间变化较大,电位稳定时间较长,非钝化金属和钝化能力弱的金属则相反,对铝合金来说,初始电位,稳定电位较负,其耐蚀性较好,反之则较差。对不锈钢来说,稳定电位较正,其耐蚀性较好,反之则较差。 相似文献
35.
K. Hashimoto M. YamasakiS. Meguro T. SasakiH. Katagiri K. IzumiyaN. Kumagai H. HabazakiE. Akiyama K. Asami 《Corrosion Science》2002,44(2):371-386
CO2 emissions, which induce global warming, increase with the development of economic activity. It is impossible to decrease the CO2 emissions by suppression of the economic activity. Global CO2 recycling can solve this problem. The global CO2 recycling consists of three district: The electricity is generated by solar cells on deserts. At desert coasts, the electricity is used for H2 production by seawater electrolysis and H2 is used for CH4 production by the reaction with CO2. CH4 which is the main component of liquefied natural gas is liquefied and transported to energy consuming districts where CO2 is recovered, liquefied and transported to the desert coasts. A CO2 recycling plant for substantiation of our idea has been built on the roof of the Institute for Materials Research in 1996. Key materials necessary for the global CO2 recycling are the anode and cathode for seawater electrolysis and the catalyst for CO2 conversion. All of them have been tailored by us. They have very high activity and selectivity for necessary reactions in addition to excellent durability. A pilot plant consisting of minimum units in an industrial scale is going to be built in three years. 相似文献
36.
Recently, AAR was identified in submerged piles of some bridges in tidal waters. Microstructural examination detected chloroaluminate salts in some cracks. To clarify whether seawater had influenced the deterioration an experimental program was planned to examine the effects of sodium chloride on AAR under various curing conditions.Concrete prisms containing either of highly-reactive, slowly-reactive or nonreactive aggregate, and either low or high alkali contents, were stored in saltwater (representing seawater) or at 100% RH, at temperatures of 38, 60 and 80 °C, for expansion measurement over 600 days, after which the temperature for those stored in saltwater was lowered to 23 °C, to check its effect on further expansion, which could be attributed to precipitation of ettringite and/or Ca-chloroaluminate.The results indicate that the type of aggregate and concrete alkali content had the greatest effect on AAR expansion. Exposure to saltwater did not have any significant effect on the AAR expansion. 相似文献
37.
Thomas C. Timmes 《Desalination》2010,250(1):6-353
The objectives were to investigate the performance of a pilot-scale electrocoagulation (EC) reactor and to determine the feasibility of using in-line EC as a pretreatment to ultrafiltration (UF) of seawater. Work was conducted at Port Hueneme, CA, using components of a U.S. military water purification system. Ferric chloride in-line coagulation was also tested. Both the EC and ferric chloride pretreatments improved UF membrane performance compared to UF without in-line coagulation. EC resulted in slightly greater increases in transmembrane pressure (TMP) than observed following ferric chloride pretreatment during sub-critical flux UF. Substantial accumulation of precipitates developed on the EC electrodes during the testing period. X-ray diffraction identified magnetite, maghemite, lepidocrocite, and akaganeite phases. Accumulation of these precipitates was due in part to conservative hydraulic design of the EC unit. It is recommended that EC units should be designed with short hydraulic retention times and higher electrode current density in order to increase upflow (scour) velocity and thus inhibit accumulation on the electrodes. Progressively longer cycling times for polarity reversal are also recommended. This research indicates that EC offers the potential for a feasible and effective pretreatment strategy for mobile water production facilities. 相似文献
38.
In bench-scale tests of seawater reverse osmosis desalination it is important to carefully consider osmotic pressure effects and determine the extent of concentration polarization so that sources of flux variation—whether from fouling, compaction, or osmotic pressure changes—can be properly assessed. Rigorous modeling of concentration polarization is difficult because of the complex geometries and flow regimes in RO modules; typically, concentration polarization must be measured. However, concentration polarization measurement usually requires knowledge of membrane permeability, which can vary from coupon to coupon. In this study a method is presented to determine both the membrane permeability and the concentration polarization regime in a single test. The key to the test is to allow the salt concentration to vary over time in a predictable way and extract parameters from a model fitted to the flux data. The usefulness of this technique is highlighted by evaluating results from several seawater experiments. It was found that specific flux decline in the experiments was caused by changes in osmotic pressure and membrane compaction. RO fouling by seawater organic-matter was not significant for the several seawater samples tested. 相似文献
39.
The micro-arc oxidation (MAO) coatings were prepared in four different electrolyte systems, including mixed acid, phosphate, phosphate-aluminate and phosphate-silicate electrolytes. The friction and wear properties of MAO coatings in ambient air, seawater and four groups of saline solutions related to seawater were investigated. The results showed that the addition of silicate to phosphate could increase the density of the coating. The phosphate-aluminate ceramic layer exhibited the lowest wear rate in various environments. Additionally, the friction coefficient and wear rate of MAO coating in seawater were lower than those in ambient air, which was due to the boundary lubrication effect of seawater. Meanwhile, the presence of divalent metal salts in seawater made its lubricity better than other salt solutions. 相似文献
40.
There has been increasing interest in clean energy over past few years. Ocean Thermal Energy Conversion (OTEC) power plants have been examined as a viable option for supplying clean energy. This paper evaluated the thermodynamic performance of the OTEC power system. Computer simulation programs were developed under the same conditions but with various working fluids for a closed system, a regeneration system, an open system, a Kalina system, and a hybrid system. The results showed that the regeneration system using R125 showed a 0.17 to 1.56% increase in system efficiency. Moreover, the system can generate electricity when the difference in temperature between the warm and cold seawater inlet temperatures is greater than 15 °C. In addition, the system efficiency of OTEC power plants using the condenser effluent from a nuclear power plant instead of surface water was increased by approximately 2%. 相似文献