Aperture layout for vapor-liquid contact tray

A vapor-liquid contact tray apparatus includes a tray having a plurality of apertures for passage of fluid through the tray. The apertures are arranged in a first group of three adjacent rows extending substantially parallel to a main liquid flow path of the tray. Apertures of the middle row are offset along the main liquid flow path on the tray from adjacent apertures of the other two rows to form a triangular pattern of adjacent apertures across the three adjacent rows. The apertures have a length and a width, each length is oriented substantially parallel to its row and each width is oriented substantially perpendicular to its row. Centers of adjacent apertures within each row are separated by a first spacing which is equal to or between 2.5 and 4.5 times the average length of the apertures in that row. Adjacent rows are separated by a second spacing which is equal to or between 1.5 and 2.5 times the average width of the apertures of the adjacent rows.