Application of low temperature soaking liquid in combined freezing-based desalination processes in summer

Abstract

In our previous study, it was noticed that the combined freezing, soaking and centrifugal desalination (FSCD) process is unsuitable to be applied in summer, because very little pure ice can be produced when the temperature of raw seawater used as soaking liquid reaches 27 °C. Therefore, two main efforts on the process optimization were made in this paper. One is that low-temperature seawater served as soaking liquid in all the experiments. In real industrial practice, the low-temperature soaking liquid can be obtained through melting pure ice products or recovering cold energy from cold concentrated brine. The effects of centrifugal parameters and soaking time on salt removal efficiency and ice yield rate were investigated. Second, the gravity-induced method was combined to form freezing, soaking, gravity-induced and centrifugal desalination (FSGCD) processes for further improvement of the salt removal efficiency. The influence of melting time of gravity-induced process was studied by keeping the samples ambient with an air temperature of 30 °C. Finally, the performance among different processes was compared. Results showed that the salt removal efficiency of the FSGCD process can reach up to 97.03%. The study is helpful to improve the process performance of soaking treatment in summer application. HIGHLIGHTS Low-temperature sea water rather than natural raw sea was used as the soaking liquid in summer.; The desalination effects of FSCD and FSGCD processes were investigated.; The performance of different processes was compared.; The work could provide an alternative to the FSCD process in summer application.;

Keywords

• centrifugal desalination
• combined desalination process
• freezing desalination
• gravity-induced desalination
• soaking treatment