(48c) 4-Pass Tray Design Techniques

Four Pass (4-pass) trays have been employed for many decades in the chemical and refining industries. Many papers have been published on this subject but none give a concise methodology on how to design and balance the V/L ratio on each tray panel. This paper will discuss the methodology of balancing 4-pass trays regardless if the design is based on equal bubbling area or on equal flow path length and whether or not the trays have vapor tunnels. In addition, deficiencies in current pressure drop methods will be discussed and how they relate to and affect 4-Pass tray design.