A Dynamic Flash Evaporation and Vapor Separation System for Seawater Desalination

用于海水淡化的动态闪蒸和蒸汽分离系统

• 批准号: 2002699
• 负责人: Vijay Dhir
• 金额: $ 30万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002699&HistoricalAwards=false
• 关键词: Dynamic; Flash; Evaporation; Vapor; Separation

There is a worldwide scarcity of potable water. Desalination of abundantly available seawater especially in coastal areas offers a viable option for conversion of seawater into fresh water. A number of schemes for desalination of water in the past have been developed. However, these schemes are either energy intensive or capital intensive. As a result, the cost of production of potable water is relatively high. The project will develop, analyze, and optimize a novel high-throughput desalination technique that is compact, modular, and relatively inexpensive to build and operate. In this technique solar-heated sea water from a solar pond flows through a set of injector passages, where the water becomes superheated leading to formation of vapor bubbles. Formation of bubbles accelerates the pressure drop allowing more thermal energy to be converted into vapor. The vapor-liquid mixture exits the injector passages into a larger tube tangentially. Centrifugal force generated as a result of swirl causes liquid to move outward while vapor forms a core in the middle of the separator tube. Vapor leaves the vapor core via a retrieval tube to a condenser to create potable water. Separated liquid is pumped back to the solar pond to be reheated. Having demonstrated the viability of the concept in the laboratory, the team is proposing to expand the experimental work to demonstrate the applicability of the concept over a broad range of operational parameters. Data for thermal conversion efficiency, vapor separation effectiveness and temperature and pressure profiles in the injector passages and separator tube are to be obtained. The data will be used to support analytical and numerical modeling of the process. Void fraction in the separator tube is to be measured and stability of vapor core in the separator tube will be investigated under a variety of mass and momentum flux conditions. This is an area unexplored before and represents a significant intellectual challenge with respect to meaningful experiments and analytical/numerical modeling. Gained knowledge will be used to optimize thermal conversion efficiency and vapor separation effectiveness under a range of flow conditions and temperatures of water exiting the solar pond. Lastly experimental effort will be used to develop an operational map that could be of great value for practical implementation of this novel concept at atmospheric and sub-atmospheric pressures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

全世界都缺乏饮用水。特别是在沿海地区，对丰富的可用海水进行淡化，为将海水转化为淡水提供了一个可行的选择。过去已经制定了许多海水淡化计划。然而，这些计划要么是能源密集型的，要么是资本密集型的。因此，生产饮用水的成本相对较高。该项目将开发，分析和优化一种新型的高通量海水淡化技术，该技术结构紧凑，模块化，建造和运营成本相对较低。在这种技术中，来自太阳池的太阳能加热的海水流过一组喷射器通道，在那里水变得过热，导致形成蒸汽泡。气泡的形成加速了压降，允许更多的热能转化为蒸汽。汽液混合物从喷射器通道切向地进入较大的管中。由于涡流产生的离心力导致液体向外移动，而蒸汽在分离器管的中间形成核心。蒸汽通过回收管离开蒸汽核心到冷凝器以产生饮用水。分离出来的液体被泵回太阳池重新加热。在实验室证明了这一概念的可行性之后，该小组提议扩大实验工作，以证明这一概念在广泛的操作参数范围内的适用性。将获得热转换效率、蒸汽分离效率以及喷射器通道和分离器管中的温度和压力分布的数据。这些数据将用于支持该过程的分析和数值建模。将测量分离器管中的空隙率，并将研究在各种质量和动量通量条件下分离器管中的蒸汽核心的稳定性。这是一个以前从未探索过的领域，在有意义的实验和分析/数值建模方面代表了一个重大的智力挑战。所获得的知识将用于在一系列流动条件和离开太阳能池的水的温度下优化热转换效率和蒸汽分离效率。最后，实验工作将用于开发一个操作图，这可能是在大气压和亚大气压下实际实施这一新概念的巨大价值。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。