Analysis of air humidification in a bubble column

Secure, affordable and resource efficient water supply systems will be as significant for future societies as energy systems. Therefore, thermal water treatment systems are necessary in the future. Humidification Dehumidification (HDH) technology, which works like the natural water cycle of the earth, is a promising process. The humidification of air on a warm surface like the ocean, the subsequent ascent of warm and humid air, the cooling in higher regions like the mountains and the related formation of fog or rain are realized in a technical process. However, humidification of air especially in a bubble column has just been insufficiently investigated in science so far. Hence, mathematic expressions for the relation between humidity of air, thermodynamic and geometric boundary conditions as well as physical- chemical properties of the liquid phase are not available. However, these expressions are necessary to fully understand thermal water treatment systems and to increase their efficiency significantly. Therefore, this project aims to establish a fundamental understanding of the humidification of air in a bubble column for thermal water treatment systems. Based on an extensive experimental data set, the aforementioned mathematical expressions will be deduced. To reach the defined goals, two experimental setups with two different fluid systems and two modes of operation will be developed, operated and analyzed within the project. The first fluid system deals with solar desalination. Therefore, salt water serves as liquid phase in the bubble column. The test series focus on the influence of thermodynamic and geometric boundary conditions. The second system covers processes for industrial waste water treatment. Hence, an oil/water-emulsion is applied as raw material and, subsequently, concentrated in a batch-wise process to get water and concentrated oil as product. The batch-wise operation results in an understanding of the influence of changing physical- chemical properties during the concentration process. The semi-empirical correlations for the humidification of air in a bubble column which will be deduced for the first time in this project will help to replace commonly applied assumptions with experimentally validated equations. This is necessary to reduce uncertainties during simulation and technology design, and to increase the efficiency of thermal water treatment systems based on HDH technology in the future.

No additional funding sources recorded.