Experimental Evaluation of Corrugated Feed Channel of Direct Contact Membrane Distillation

Abstract

Membrane distillation is a hybrid process in which the separation process is based on both thermal potential and membrane characteristics. However, some technical challenges such as thermal boundary layer builds up (temperature polarization) resulted in low mass flux. In this study, the direct contact membrane distillation is equipped with corrugated feed channel to create fluid mix for mass flux improvement. A lab scale flat sheet membrane distillation is assembled with corrugated feed channel to suppress the thermal boundary layer in the vicinity of the membrane wall. The flat sheet PTFE-membrane of a pore size of 0.45 μm and porosity 65% is considered in the present study. The effect of feed channel gap height has been investigated at different values of flow rate, feed temperature, and feed salinity.The experiments showed that the corrugated feed channel has a dominant effect of improving of the mass flux and the thermal efficiency rather than gap height and operating conditions. The experimental results showed the water flux and thermal efficiency of the corrugated feed channel module is 44% and 33% higher than the original module respectively. NomenclatureA: Membrane area, m 2 Cp: Specific heat capacity of fluid (J kg −1 K −1 ) LHv: Latent heat of vaporization of water (J kg −1 ) Nm: Water flux (kg m −2 s −1 ) EE: Energy efficiency (%) T: Temperature (°C) m: Mass flow rate ( kg/sec.)

Optimizing Membrane Distillation Performance through Flow Channel Modification with Baffles: Experimental and Computational Study

“…Another route to mitigating the polarization effects is increasing the chaotic state of the flow near the membrane surface, such as increasing the feed velocity and using pulse flow [22,23] or filling the spacers in the flow channels [24][25][26][27]. It has been reported that changing the geometry of the MD module channel is an effective approach to increasing the chaotic state of feed and coolant [28][29][30][31]. Kuang et al have researched the potential of adding baffles on flow channels to enhance direct contact membrane distillation (DCMD) performance [32].…”