In the tube falling film evaporator

liquid level directly influences the pressure and the temperature in the evaporator and therefore influences the heating steam consumption. So

it is an important parameter for optimization of evaporator operation. But in the actual production

the liquid level is usually set empirically in a large range

so that the process cannot run in optimal situation. A liquid level optimal-setting method based on exergy analysis is proposed. By deeply analyzing the liquid level's effect on other evaporation parameters and using the actual running data of the sodium aluminate solution evaporation process for alumina production

the correlations between liquid level and other parameters are obtained. An optimization model based on the maximum exergy efficiency is then established based on the material balance of the evaporator and the exergy analysis method. The optimization model is then solved under a certain condition to get the exergy efficiency-liquid level curve. Finally the optimal level under different operating conditions is calculated

which provides guidance for the optimization of the actual production operation.