Desalination processes based on multi effect are in wide use in the chemical industry for separation of ingredients from solution mixtures. However, seawater desalination using this process has not achieved the commercial importance compared to the multi stage flash process in terms of the total installed capacities. In view of recent technological advances there are a number of good indications that this situation may change in favor of the multi effect process. This paper reviews the different basic evaporators employed in distillation processes aid their principle operations. The paper then provides an approximate comparative analysis of the horizontal tubular anti plate type evaporators with respect to heat transfer area requirement, pressure drop, flow pattern and heat transfer coefficients.