Prediction of Hydrostatic Head Effect in Process Plant Evaporators by Nomograph

Abstract

Evaporation in process plant evaporators is influenced by two common phenomena, viz. Solute effect and Hydrostatic head effect, which elevate the boiling point of the solution thereby reducing the available temperature difference driving force for boiling heat transfer and increasing the heat transfer area. Although literature provides information in the form of plots and nomographs(1,2) for a quick estimate of boiling point elevation for different solutes in their solutions, available information for the prediction of hydrostatic head effect is scanty'31. The effect of hydrostatic head on the boiling heat transfer is quite appreciable in many situations and cannot be ignored especially for evaporators operating under moderate to high vacuum and when the liquid-level' is fairly high above the tube bundle.