Experimental Study of Solar Pond Coupled With Forced Circulation Crystallizer as Major Stages of Proposed Zero Discharge Desalination Process

Pretreatment, solar pond (SP), and forced circulation crystallizer (FCC) are the basic stages of one option to provide the goals of zero discharge desalination (ZDD) process. This work represents the performance of a solar pond that is coupled with forced circulation crystallizer as second and third stages of proposed zero discharge desalination process. The purpose of ZDD in this paper is gathering fresh water and saline crystals from effluent wastewater of the desalination unit of Mobin petrochemical complex. So, the SP unit is constructed after the pretreatment unit to concentrate the treated wastewater to about 20 wt. % as a suited feed for the FCC unit. Effects of solar insolation rate are investigated experimentally, during a year. In addition, the effect of cooling water flow rate of FCC on quality of effluent stream from SP as feed crystallizer is studied in this paper. The experimental results show the maximum evaporation rate from SP is obtained 5 l/(m²·d) when the insolation rate was about 2.5 × 10⁴kJ/(m²·d). Experiments show the suitable range of crystals growth (710 μm to 830 μm) in FCC is occurred when the cooling water flow rate in condenser is 9 kg/min. The size and the color of produced salt crystals will be optimized in this flow rate and energy consumption is measured as 6.98 kW·h.