Fresh water from the sea,a new process

• 1. 1. The process is designed to produce ice crystals uniform in shape and size, without the formation of other new nuclei.
• 2. 2. Nucleation and crystal growth are separate operations; the former is batch-wise; the latter is continuous.
• 3. 3. The predetermined number of nuclei charged to the crystal chamber is equal to the production per unit divided by crystal weight.
• 4. 4. The refrigerant is supplied along the flow path in the chamber at a rate equivalent to the crystal growth rate.
• 5. 5. Separation of the uniform crystals from the residual sea water is a true gravity operation - the less dense ice floating away from the more dense residual sea water.

     

Optofluidic opportunities in global health, food, water and energy

Optofluidics is a rapidly advancing field that utilizes the integration of optics and microfluidics to provide a number of novel functionalities in microsystems. In this review, we discuss how this approach can potentially be applied to address some of the greatest challenges facing both the developing and developed world, including healthcare, food shortages, malnutrition, water purification, and energy. While medical diagnostics has received most of the attention to date, here we show that some other areas can also potentially benefit from optofluidic technology. Whenever possible we briefly describe how microsystems are currently used to address these problems and then explain why and how optofluidics can provide better solutions. The focus of the article is on the applications of optofluidic techniques in low-resource settings, but we also emphasize that some of these techniques, such as those related to food production, food safety assessment, nutrition monitoring, and energy production, could be very useful in well-developed areas as well.     

Drinking water from sea water by forward osmosis

Potable water may be extracted from a saline source, such as the ocean, using a concentrated solution of nutrients and a semipermeable membrane. This paper applies the previously presented theory (1) of the forward osmosis extractor to this case and compares that theory with experiment. Theory and experiment are found to match well. Calculated and observed magnitudes of water extraction rate and nutrient utilization indicate that practical devices may be constructed. It is found that the volume of water obtained per mass of nutrient meets the human requirement for fluids and nutrient. Optimization of the system is discussed.     

Production of magnesite from sea water in Britain

Refractories and Industrial Ceramics -     

Sintering of magnesium oxide obtained from sea water

The process of isothermal sintering of magnesium oxide obtained from sea water (by precipitation with 80% and 120% of the stoichiometric quantity of the precipitation agent respectively) and of reagent grade magnesium oxide was examined with addition of 0·5% TiO₂, at a temperature of 1600°C, for different durations of isothermal sintering and for different pressures applied in the forming of compacts.

Product density, shrinkage and porosity were examined, and the results obtained were analysed mathematically. The effect of the TiO₂ in the magnesium oxide sample on the content of B₂O₃ was also determined. Coefficients have been calculated for associated reactions, namely those for the formation of Ca₂B₂O₅ and CaTiO₃.     

Evaluation of energy and dietary intake estimates from a food frequency questionnaire using independent energy expenditure measurement and weighed food records

Background  

We have developed a food frequency questionnaire (FFQ) for the assessment of habitual diet, with special focus on the intake of fruit, vegetables and other antioxidant-rich foods and beverages. The aim of the present study was to evaluate the relative validity of the intakes of energy, food and nutrients from the FFQ.     

Assessment of energy consumption in desalination of sea water on the basis of conceptual designs and surveys

Energy equivalent of sea water desalination are quoted as the most suitable measure in the phase discussing here from various survey reports in Japan which include conceptual designs of desalting plants such as dual purpose systems and MSF processes to utilize industrial waste heats.These systems are alloted for supplementing the shortage of drinking water from rivers which may dependent on the rainfall. Then, a diagram is proposed to indicate preferable region for construction of desalting plants or river development from view points of both energy consumption and economyThese ideas were applied to the survey for introducting desalting plant in an industrial city and the necessary energy to produce fresh water from the sea was estimated for the case of 1/10 arid year. The amount of the order of a little less than 1% to the total energy consumption of the city should be evaluated from the view point of total human activities     

海水提溴技术的发展与研究现状

溴素是重要的化工原料之一,在阻燃剂、石油开采、杀菌剂、农药、感光材料及医药等领域广泛应用,其制备技术和应用价值受到国内外学者的高度重视。综述了国内外溴素生产现状和海水提溴的方法,介绍了空气吹出法、水蒸气蒸馏法、离子交换吸附法和膜分离法提溴技术的研究现状,分析了各种方法的优缺点。简述了超纯溴的制备方法。提出了海水提溴的未来发展方向。     

潮汐影响海水沉淀池运行的原因分析与对策

海水退潮过程中反应沉淀池沉淀区出现翻池,絮凝体大量上浮严重影响出水质量.通过对海水潮汐过程中海水变化的分析,找出导致此现象发生的根本原因是海水密度和浊度变化使池内水流产生异重流.作者结合沉淀池结构对异重流流态及其对沉降效果的影响进行了分析,并在此基础上提出了有效的应对方案.     

Reverse osmosis in the desalination of brackish water and sea water

To make RO an economical process, plant and operating costs have been reduced by developing compact modules, led by polyamide hollow fibre modules which recover energy from the reject when desalinating highly saline brackish water and seawater. Such plants only start to pay their way at product rates of around 400m³ /d +. Energy costs for desalination systems with lower capacities can also be reduced considerably by operating the RO plants at conversion rates of more than 30%. To what extent the required higher conversion rates can be obtained for a particular application depends on concentration of scales-forming content matter (calcium sulphate, strontium sulphate, barium sulphate and calcium carbonate), salt content of the raw water, concentration of fouling substances such as iron, manganese, anorganic and organic matter, risk of biological growth due to algae, shells and bacteria. The scope and type of conditioning and pre-treatment are based on these factors.     

Extraction of uranium from sea water using biological origin adsorbents

Waste microbial biomass has been shown to be a good adsorbent for uranium. A small scale pilot plant was operated at Woods Hole Oceanographic Institute in collaboration with the Department of Nuclear Engineering of MIT in order to assess the potential use of the two selected types of microbial biomass to sequester uranium from sea water effectively. The experimental results suggest that factors such as the presence of carbonates in the sea water, suppress substantially the uranium adsorptive uptake capacity of the biomass. The selectivity of the biomass for uranium, is not as good as that of other synthetic inorganic or organic adsorbents as, for example, hydrous titanium oxide.     

Membrane processes for water,pulp and paper,food state of the art

General trends, observations and personal viewpoints are presented on membrane processes for the water, pulp and paper, and the food industry. Thus electrodialysis, reverse osmosis and ultrafiltration are considered form their historic and economic aspects, and thoughts are advanced on how and why institutions and companies have entered this technology and which entities will be leading the development in the eighties.     

Energy, water and process technologies integration for the simultaneous production of ethanol and food from the entire corn plant

This paper presents simultaneous integration of different technologies such as the traditional dry-grind process to obtain ethanol from grain with the gasification of the corn stover followed by either syngas fermentation or catalytic mixed alcohols synthesis. The optimal integrated process when using the entire corn plant (18 kg/s of grain and 10.8 kg/s of stover) is the one in which the dry-grind technology to process corn grain is integrated with the catalytic path for the corn stover due to the improved integration of energy, requiring only 17 MW of energy, 50 MW of cooling and 1.56 gal/gal of freshwater, for an ethanol production cost of 1.22 $/gal. However, the production cost decreases as we only use stover to produce ethanol, while the grain is used for food due to the lower cost of the stover and the more favorable energy balance of the ethanol production process from gasification.     

Initial fouling of nontoxic coatings in fresh,brackish, and sea water

Objectives of this project were to evaluate benefits — over the short term — that might derive from control of the surface properties of materials used in energy transfer devices; and to identify preferred ranges of surface parameters that might be specified to minimize deposits of biological fouling known to deteriorate energy exchange efficiencies in seawater, brackish water, and freshwater systems. By modifying the surface chemistry and surface energy of test plates with very thin coatings (nontoxic) and examining the acquired films at various time intervals, the earliest events of biofouling caused by macromolecules and microbial organisms were defined. Overall, the results were remarkably similar for all systems tested in showing that deliberate modification of the initial material surface qualities can significantly reduce the retention of biofouling layers.     

活性炭对海水中硼的吸附研究

未处理的生活污水和海水中均含有一定量的硼，给人们的生产和生活带来严重影响，因此，微量硼的分离与去除意义重大。利用活性炭吸附法吸附溶液中的微量硼，对其影响因素如接触时间、吸附质质量浓度、pH、吸附剂量及温度等进行了研究，并对比了动静态吸附及酸碱再生效果，确定了适宜的实验条件。应用该法吸附某海水中的微量硼，其一次除硼率可达90％以上，硼质量浓度达到WHO规定饮用水的要求。     

可再生电力电解制绿色氢能的发展现状与建议

氢能是人类生存和发展所需能源的重要补充。氢能产业,特别是氢燃料电池车,其开发与利用已经引起了全球范围内的普遍重视。然而,决定该产业快速发展的关键因素之一是清洁的氢气来源,如何使氢能产业更具经济环保竞争力。通过可再生能源发电电解水制氢将能量以化学能的形式储存起来,不仅能利用可再生能源制取高热值的氢气供使用,同时从制氢源头利用清洁的可再生能源可有效减少碳排放。为此,本文主要分析讨论了可再生能源发电与电解水制氢技术的耦合制取氢气的发展现状与发展趋势,简述了目前国内外利用可再生能源发电制取氢气项目的研究进展,并介绍了一些典型的清洁制氢案例。可以看到,风电、太阳能制氢是目前较为成熟的技术,但仍需提升其经济竞争力。而水电资源分布不均等缺点阻碍了其规模化发展。因此,政府、企业及科研院所需大力推进可再生能源发电制氢研究,有效解决氢能制备的效率问题,加速绿色氢能产业发展。