Development of thermal scheme of gas contact desalination plant and analysis of its application conditions

Flue gases of various power plants are widely used as a heating medium in waste heat boilers, contact heat exchangers with an active nozzle, and regenerative heat exchangers. Use of flue gases in the process of obtaining desalinated water is one of the promising directions of using heat of flue gases. The exhaust gases in most existing desalination plants are used only to heat desalinated water, in this case, this process is carried out in regenerative heat exchangers. However, contact heat exchange makes it possible to increase the efficiency of the desalination process. Combustion products contain greenhouse gases that have a negative impact on the environment, but at the same time have an energy potential that can be effectively used. In this regard, the tasks of the development of technologies that allow us to utilize heat of the exhaust gases, as well as to purify them, are relevant. Balance calculation methods have been used to develop a method for calculating the thermal scheme of a desalination plant and evaluating the effectiveness of the desalination process. A thermal scheme of a gas-contact desalination plant with adiabatic humidification of flue gases has been developed. The effect of flue gas temperature and sea water salinity on the efficiency of the installation has been determined. The use of flue gases in the process of obtaining desalinated water in contact desalinators allows us not only to obtain fresh water suitable for technical needs, but also to purify combustion products. As a result of balance calculations, it has been found that a change of the temperature of exhaust gases during adiabatic humidification from 365 to 120 °C leads to a 2,62-fold decrease in the productivity of gas-contact type installations. An increase of the initial salinity of seawater entering the installation leads to an increase of its consumption by 8,5 %.