Selective condensation apparatus

A falling film surface condenser for selective condensation of vapor comprising at least one plate element including a pair of plates joined around their peripheries and spaced apart throughout substantially all of the area defined within said peripheries so as to allow for the flow of vapor through the plate element;

• a slanting internal partition located between and joining the plates across part of the width of the plate element from an upper partition end spaced from said peripheries to a lower partition and sealingly secured at a side edge of the plate element, said partition separating upper and lower internal spaces within the plate element, means for introducing vapor to be condensed in said plate element, and at least two outlet means for condensates formed by vapor condensing within the plate element and a liquid coolant distribution means located above the plate element such that the vapor passes in countercurrent flow to the liquid coolant distributed to said plate element.