Vapor-liquid two-phase continuous distillation tower

Structural features:
The new type of dual phase continuous sieve tray tower plate has various forms of structure: it is equipped with lifting holes (circular, square, rectangular holes, etc.) on the tower plate, and various forms of caps (such as cylindrical, column shaped, rectangular, square, ladder rectangular) are arranged on the holes and equipped with downcomers. The setting of the downcomer is basically the same as that of ordinary trays (float valve, sieve plate, bubble cover tray). The characteristic of biphasic continuity is mainly reflected in the construction of the hood, among which the most common and typical circular hood (known as the standard hood). It consists of a cover body, a top cover, and a guide baffle, and its material can be stainless steel, low-alloy steel, or ceramic.

Operating principle:
The gas-liquid flow contact is in a jet state, as shown in Figure 2. The liquid from the previous tray flows out of the downcomer, passes horizontally through each row of cap covers, and flows into the bottom gap of the cap covers. The gas from the next tray rising from the orifice plate pulls the liquid film, and the airflow and liquid undergo intense heat and mass exchange inside the cover. Then, the two-phase flow is sprayed out horizontally from the nozzle holes on the cover wall. After the gas phase and liquid droplets churn and separate in the space between the plate droplets, the gas phase rises to the upper tray, while the liquid droplets ejected from each cap collide with each other, causing some small droplets to merge and become larger, falling and landing on the tray together with the original large droplets. Some of them are then sucked into the cap and stretched and broken again. The remaining part follows the liquid flow on the plate into the next row of caps or winds around inside and outside a cap, and finally flows through the downcomer to the lower tray. The contact condition of gas-liquid flow can be summarized into the following four consecutive sections: ① Liquid holding and membrane pulling section; ② Film breaking and crushing section; ③ Gas liquid injection section; ④ Gas liquid separation section. There is gas-liquid mass transfer in all four consecutive sections, especially in section ④ which is more important. The pull film in the hood is not a uniformly thick circular film, and its thickness is very uneven and unstable, resembling a hollow shape. The height and thickness of this bowl shaped membrane vary with the gas velocity. As the gas velocity increases, the membrane thickness becomes thinner, making it more prone to breakage. The droplet size is also smaller, and it disperses better in the gas phase. In addition, the collision between the airflow and droplets in the hood, as well as the turbulence outside the hood after being ejected, become more intense.

Technical performance:
Large processing capacity, high mass transfer efficiency, low pressure drop, good operational flexibility, strong adaptability to operating conditions, good anti clogging ability, and good operation
Good stability and small spacing between trays.