Tower internals are components of packed towers and plate towers. Plate towers are also called tower plates. They are mainly used for gas-liquid contact on the plate surface in the form of gas bubbling and liquid spraying. Heat transfer and mass transfer have obvious "step" processes. The packed tower, chemical packing and tower body together form a complete packed tower. The role of tower internals is to maximize the efficiency and production capacity of the packed tower, rather than limiting the performance of chemical packing. Therefore, the quality of tower internals directly affects the performance of the entire packed tower.

The so-called "amplification effect" of the packed tower is greatly affected by the tower internals in addition to the inherent factors of the chemical packing itself. Before the 1970s, due to the imperfect tower internals, a 50% margin was often reserved for the tower cross-sectional area or packing layer height when designing the packed tower. This design concept is absolutely not allowed under the current energy-saving and competition mechanism. The energy crisis in the early 1970s prompted the improvement of packed tower design, which is closely related to the research and development of tower internals.

The tower internals mainly include the following parts: liquid distribution device; packing fastening device; packing support device; liquid collection and redistribution, wall flow prevention and feeding and discharging device; gas feeding and distribution device; mist removal device.

Abnormal operation phenomenon of tower internals:

1) Entrained liquid foam: For a certain liquid flow, the greater the gas velocity, the greater the liquid foam entrainment, and the thicker the liquid layer on the tower plate. The increase in liquid layer thickness is equivalent to the decrease in the plate spacing, which increases the impact on the amount of liquid foam entrainment. Therefore, when the gas velocity increases to a certain value, a vicious cycle will inevitably occur on the tower plate. The liquid layer on the plate continues to thicken and cannot reach equilibrium. Eventually, the liquid will fill the entire tower and overflow from the top of the tower with the gas. This phenomenon is called entrained liquid foam.

2) Overflowing liquid foam: The liquid foam caused by the limitation of the downcomer's passing capacity is called overflowing liquid foam. Too much plate pressure drop is usually the main reason for the high liquid level in the downcomer. Therefore, plates with large plate pressure drop are more likely to overflow liquid foam. It can be seen that excessive gas velocity will also cause overflow liquid foam. In addition, if the resistance of the downcomer of a tower internal increases sharply (such as blockage), it will also cause overflow liquid foam.

3) Liquid leakage: When the gas flow rate is low, part of the liquid on the tower plate will fall directly from the sieve hole. This phenomenon is called liquid leakage. In addition to the structural factors of the tower internals, the gas velocity is the main factor that determines whether the tower plate leaks.