This study aimed to optimise an air gap membrane distillation (AGMD) system for seawater desalination with respect to distillate production as well as thermal and electrical energy consumption. Pilot evaluation data shows a notable influence of evaporator inlet temperature and water circulation rate on process performance. An increase in both distillate production rate and energy efficiency could be obtained by increasing the evaporator inlet temperature. On the other hand, there was a trade-off between the distillate production rate and energy efficiency when the water circulation rate varied. Increasing the water circulation rate resulted in an improvement in the distillate production rate, but also an increase in both specific thermal and electrical energy consumption. Given the small driving force used in the pilot AGMD, discernible impact of feed salinity on process performance could be observed, while the effects of temperature and concentration polarisation were small. At the optimum operating conditions identified in this study, a stable AGMD operation for seawater desalination could be achieved with specific thermal and electrical energy consumption of 90 and 0.13 kW h/m3, respectively. These values demonstrate the commercial viability of AGMD for small-scale and off-grid seawater desalination where solar thermal or low-grade heat sources are readily available.
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机译:这项研究旨在优化用于海水淡化的气隙膜蒸馏(AGMD)系统,以提高馏出物的产生以及热和电能的消耗。初步评估数据显示,蒸发器入口温度和水循环速率对过程性能有显着影响。通过提高蒸发器入口温度,既可以提高馏出物产率,又可以提高能源效率。另一方面,当水循环速率变化时,在馏出物产率和能量效率之间存在折衷。水循环速率的提高导致馏出物产率的提高,但是比热和电能的消耗也增加。鉴于在试验性AGMD中使用的驱动力较小,可以观察到进料盐分对工艺性能的明显影响,而温度和浓度极化的影响很小。在本研究确定的最佳运行条件下,可以实现稳定的AGMD海水淡化运行,具体的热能和电能消耗分别为90和0.13 kW h / m3。这些值证明了AGMD在小规模和离网海水淡化中的商业可行性,在这些海水淡化中,太阳能热或低级热源很容易获得。
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