Distribution of brine temperature in a large-scale horizontal-tube falling film evaporator

摘要

Falling film evaporator applied in multi-effect evaporation device is normally operated under small temperature differences. Considering the high sensitive of the evaporator, the distribution of the brine temperature, as one of the parameters that determines the distribution of the local temperature difference, is studied in this paper using parameter distributed model. The three-dimensional distributions of the brine temperature as well as the location of the maximum brine temperature are presented under different operating conditions. Results show that the maximum variation range of the brine temperature in the evaporator decreases with the increment of the brine inlet spray density and salinity but increases with the increment of the apparent temperature difference. In the aim of avoid design failure of the local temperature difference, the variation of the location of the maximum brine temperature as well as the thermodynamic losses in the brine film are analyzed, providing theoretical basis for the more accurate design of the falling film evaporator.