Influence and CFD analysis of cooling air velocity on the purification of aqueous nickel sulfate solutions by freezing

Abstract

in Wiley Online Library (wileyonlinelibrary.com)Finite energy resources and their rapidly waning imprint necessitate a sustainable wastewater treatment method. Nature could be exploited to freeze wastewater in locations which experience subzero temperatures during winter. The two most vital components that influence the efficiency of natural freezing are the ambient temperature and air velocity. The turbulent and unsteady air-cooled natural freezing is simulated for ice crystallization from 0.1 wt % and 1 wt % NiSO 4 (aq) solutions. The efficiency of natural freezing is tested for different air velocities (2 ms 21 , 5 ms 21 ) and levels of undercooling (DT 5 0.58C, 18C) from the freezing temperature of the corresponding solution. The airflow in the winter simulator is modeled by computational fluid dynamics to investigate its behavior and to assess its effect on freezing.Symbol: • and -represents freezing test results with v 5 0.25 ms 21 and the linear relationship between G and K as obtained in our previous publication. 5 Symbol: o, represents freezing test results in the current setup as shown in Figure 1 with v 5 2 ms 21 ; 1, with v 5 5 ms 21 and *, with v 5 5.5 ms 21 after subduing the effect of vibration.

Purification efficiency of natural freeze crystallization for urban wastewaters

“…8). The same trend was seen also in previous studies for freezing salt solutions of different concentrations when plotting the purification efficiency in terms of the effective distribution coefficient as a function of the ice layer growth rate Louhi-Kultanen, 2015, 2016;Hasan et al, 2018). Based on this observation, it can be deduced that the type of wastewater (i.e.…”

“…However, the ice layer growth rates obtained in our previous study with electrolyte solutions (nickel sulphate) correspond somewhat with the growth rates in freezing of wastewater found in this work. For similar conditions (T = 1 K, vair = 2 ms -1 , 24 h), the salt solutions had an average ice layer growth rate of ~2.5 10 -7 ms -1 (Hasan et al, 2018) and in this study the average rate was 2.05 10 -7 ms -1 .…”

“…Winter simulator apparatus with a similar set-up was used in our previous freezing experiments with electrolyte solutions (Hasan et al, 2018). Plus software.…”

Measurement and evaluation of natural frequencies of bulk ice plate using Scanning Laser Doppler Vibrometer

“…In air-cooled natural freeze layer crystallization, ice crystals form a layer on the water surface, which grows downwards into the liquid. Natural ice crystallization due to forced heat convection was simulated with a wind tunnel-like apparatus introduced in more detail in previous studies by Hasan et al [8].…”