Eddy diffusivity for distillation sieve trays

An understanding of the eddy diffusivity on a distillation tray is important to accurately predict the distillation tray efficiency from the point efficiency. This article presents a new correlation to predict liquid‐phase eddy diffusivity (De) on sieve trays. This correlation has been developed by modeling backmixing as the trajectory motion of liquid droplet elements through the two‐phase layer height on the tray. The trajectory model indicates that De is a strong function of the two‐phase layer height. An expression for froth height is derived. The new De correlation offers two main improvements over existing literature correlations. First, this model is phenomenologically‐based and, therefore, not limited to air/water. Second, the new De correlation gives significantly lower average actual and relative errors and a lower standard deviation of the actual error than do other available correlations.