Energy transfer and efficiency analysis of microwave flash evaporation with tap water as medium

A microwave flash evaporation system is designed and applied to research the intensification effect of microwave on flash evaporation, in present work, a mathematic model of the energy transfer and efficiency of microwave flash evaporation (MFE) process is presented, and series of experiments used water as medium are conducted. Production rate, thermal efficiency of phase transition, thermal proportion of steam, electro-thermal conversion efficiency, and indicator parameters such as, gain output ratio (GOR), specific thermal energy consumption (STEC), and total volumetric heat transfer coefficient are calculated to evaluate energy transfer of MFE process. As a result, the production rate, thermal conversion efficiency and thermal proportion of steam increase with microwave power but decrease with flow rate, and the maximum value of electro-thermal conversion efficiency achieved 76.66%. GOR value and total volumetric heat transfer coefficient of MFE increase with microwave power but decrease with flow rate, the specific thermal energy consumption increases with flow rate but decrease with microwave power. In addition, the economy of MFE process is also discussed. This work may provide the theoretical support for the feasibility of the utilization of microwave heating in flash evaporation.