Is the liquid level on the trays of a distillation column constant?

Under normal operating conditions, the liquid level remains essentially constant; the function of the overflow weir is to maintain this liquid level at the level of the weir itself (slightly above its height). Abnormal situations such as severe leakage or a large amount of foam entrainment are not necessarily the case.

The height of the overflow weir is also its thickness; generally, as long as it can ensure the flow rate of liquid entering. Under the process conditions within the design range, if the amount of rising vapor remains constant and the amount of liquid flowing downstream decreases, this will result in less liquid on the lower tray levels, as well as a reduction in the liquid layer thickness. However, the resistance encountered in the generation of steam will decrease, and the poorly volatile components cannot be separated as required by the design. If the liquid volume remains constant, a decrease in the amount of vapor rising can lead to liquid leakage; on the other hand, an increase in the amount of vapor rising can blow away the liquid layer on the tray, causing it to become suspended in the form of foam, which results in \"liquid flooding\" (also known as \"liquid suspension\"). ) The rising steam is blocked, causing a large amount of liquid to overflow downstream; flow stops, which results in fluctuations in the rising steam. If such a phenomenon occurs, the dosage should be reduced immediately; once the operating conditions return to stability, it can be gradually increased back to the design value. For reference.

Under normal operation, does increasing the reflux rate cause a change in the liquid level height on the tray? Basically slightly higher than the overflow weir?