Solvent deasphalting extraction tower level

The level gauge located at the lower part of the extraction tower is used to monitor and control the liquid level at the bottom of the tower. Even when liquid-liquid extraction is employed, it is still necessary to maintain a certain liquid level there, in order to ensure sufficient contact between the extractant and the material to be separated, as well as for the stability and safety of the operation. There are various principles behind the operation of level gauges; common types include float-type, pressure-type, capacitive, ultrasonic, and radar types. The specific measurement principle to be chosen depends on the operating conditions, properties of the medium, and requirements for measurement accuracy. .

The level gauge installed at the bottom of the liquid-liquid extraction column is used to measure the interface between the solvent phase (light phase) and the raffinate phase (heavy phase). The opening degree of the flow control valve for the heavy phase outlet is adjusted according to the level of liquid at this interface, in order to prevent the solvent from being drawn out along with the heavy phase when the flow rate of the heavy phase at the column bottom is too high. This design, which features an interface meter at the bottom of the tower, is typically suitable for extraction processes in which the heavy phase acts as the dispersed phase and the light phase as the continuous phase. In the area at the bottom of the tower, where the heavy-phase droplets are present, a coalescence zone is necessary so that these droplets can gather together and form a phase interface with the light phase. In extraction processes where the light phase serves as the dispersed phase and the heavy phase as the continuous phase, the interfacial meter is installed in the droplet coalescence zone at the top of the tower.