Discussion on the minimum spray density and liquid phase volume in packed towers
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(1) Minimum wetting rate: Lmin is the minimum flow rate required to ensure that the filler can be wetted. (2) The minimum liquid flow rate L in the absorption tower is used to ensure the minimum flow rate for absorption, and it is primarily determined based on the absorption coefficient ； Question: For example, the minimum liquid phase flow rate L is 70 m3/h, but the Lmin required for the packing is 13 m3/h (taking the tower diameter into account). From the perspective of forming a film on the surface of the packing, a thinner film is more favorable for absorption; however, the minimum liquid phase flow rate results in a very thick liquid film on the packing surface, which is not conducive to absorption. So, when there is a large discrepancy between these two values, should the diameter of the tower be increased, or should a packing with a larger specific surface area be used? These two data sources are: the design examples on page P258 of the \"Guide to Modern Packing Technologies\", and the design examples for packing absorption towers.
If the minimum liquid phase flow rate L is much larger than the minimum wetting rate Lmin, it is possible to consider increasing the tower diameter or using packing with a larger specific surface area. Increasing the tower diameter can reduce the liquid film thickness, while using packing with a larger specific surface area can improve mass transfer efficiency. The specific method to choose depends on a comprehensive consideration of process requirements, cost-effectiveness, and operating conditions. .