A novel separation technique - gas carrying evaporation: theory and application

摘要

To avoid or mitigate scaling or thermal deterioration in the process of evaporation a novel process-Gas Carrying Evaporation (GCE) has been developed with the concept of an `interfacial vaporization heat sink'. In the GCE process, an inert gas was introduced at the bottom of vertical heating tubes. Due to the effect of the `heat sink', the temperature of the heating wall is lowered, nucleate boiling on the heating wall is suppressed, and solvent vaporization mainly takes place at the gas-liquid interface in the two-phase flow bulk. Therefore, both thermal deterioration and scaling on the heating wall are avoided or mitigated, and the heat transfer is greatly enhanced. The process of GCE has been used in several industries for the evaporation of thermally sensitive and easily depositing solutions. In this paper, the development of GCE, the theory of heat transfer augmentation by the interfacial vaporization heat sink, and the characteristics and applications of GCE are described and discussed. (C) 2003 Society of Chemical Industry.