Optimized improvement of double-stage solar AES saline wastewater treatment system based on performance simulation and exergy analysis

Abstract

Being an innovative, clean and high-efficiency double-stage solar air evaporating separation (AES) saline wastewater treatment system, it enables the full recovery of clean water and salt from saline wastewater. Nevertheless, there are still possibilities for optimized improvement in various aspects. Therefore, in this work, a well-established and accurately system simulation model is constructed, comprehensive performance is intensively analyzed, and different optimization and improvement methods are designed. Results demonstrate that among three potential improvements, “Improvement of three-stage switching operation” brings little effect, while “Improvement of distribution relationship” can effectively improve system adaptability to weather, particularly under overcast weather conditions. Moreover, “Improvement of regenerator” improves overall performance (gained output ratio (GOR), evaporation efficiency (EE) and overall system efficiency (ηsys), which are 20.11 %, 11.01 %, and 8.55 % higher than original system, respectively). Furthermore, the exergy analysis concludes that simultaneous implementation of “Improved distribution relations” and “Improved regenerators” is preferable. This improvement enhances system weather resilience and wastewater recycling capabilities in one fell swoop. This improved system can achieve an average GOR, ηsys and system exergy efficiency (ηex) of 2.588, 63.92 % and 2.849 %, respectively, throughout total summer months. Consequently, the best system improvement method is combining “Improvement of distribution relationship” with “Improvement of regenerator”.