Sea Water Desalination Technology

Human life and production are inseparable from fresh water. However, nearly 97.5% of the world 's total water resources is salinity water such as seawater. With the rapid development of economy and population explosion, the shortage of fresh water resources has become a growing global environmental problem. Desalination technology is considered to be an effective means to solve the shortage of fresh water resources. It is the process of utilizing energy, such as heat, electricity and other energy, to separate the dissolved mineral salts, organisms, bacteria and viruses and solids of seawater. According to the separation process, the classification of seawater desalination technology is shown in Fig.1. Multi-stage flash (MSF), multi-effect distillation

At present, globally installed desalination capacities are contributing 76 million tons/year of CO2 and it will accelerate to 218 million tons/year of CO2 by 2040 [30]. In order to overcome the disadvantages of traditional desalination technology and further reducing the carbon dioxide emissions, different novel desalination technologies are developed. Exploiting low-temperature heat source such as waste heat or solar energy is an emerging and promising technology for near future. Adsorption desalination (AD) and thermal vapor compression (TVC) have been attracting significant attention in thermal desalination. Adsorption desalination is a kind of method evolved from the adsorption refrigeration system. Activated carbon, silicone and zeolites have been utilized as adsorption media. A major advantage of adsorption technology is its ability to utilize low-temperature heat source ranged from 50 °C to 85 °C. Kim Choon Ng and his collaborators [31-35] have made a great contribution to the research and development of the adsorption desalination. However, the performance of the adsorbents were reduced after being used for a period of time. This problem greatly limits the development of its application. The thermal vapor compression has a similar principle to the adsorption desalination. The TVC is attractive due to its simple operation, low maintenance cost and simplicity in construction. However, the TVC is used with the MED system, which is known as MED-TVC [36]. There are few researches about the single effect TVC in the last twenty years. The mathematical model for the single effect TVC is developed by Al-Najem and El-Dessouky in 1997 [37]. El-Dessouky et al. [38] developed a steady-state mathematical model, which considered the variation of the physical properties of water with temperature and salt concentration, boiling point elevation