What Caused Tower Malfunctions in the last 50 years?

Lessons from over nine hundred case histories of malfunctioning towers reported over the last 50 years were surveyed and analyzed. Our analysis shows growth in the number of malfunctions with no signs of decline. Plugging, especially of tray active areas, packing and distributors, tops the malfunctions list. Fouling-resistant internals are essential, but may not go far enough in aggressive fouling environments. The tower base comes second, where liquid level rising above the reboiler inlet caused premature flood and even internals damage or tower overfilling. Good level measurement and tower base design are key preventive measure. Next follow tower internals damage, abnormal operation incidents (startup, shutdown, commissioning), assembly mishaps, packing liquid distributors, intermediate draws, misleading measurements, reboilers, and controls. The survey teaches numerous lessons on each of the malfunctions which are invaluable for achieving trouble-free design and operation of distillation towers.