A New Crossflow Rotating Bed, Part 1: Distillation Performance
2014
Wang, Guang Q. | Guo, Cheng F. | Xu, Zhi C. | Li, Yu M. | Ji, Jian B.
A new kind of high-gravity device—the crossflow concentric-baffle rotating bed (CRB)—has been developed, the rotor of which contains a set of perforated concentric baffles. In this type of rotating bed, the gas flows in a zigzag pattern toward the center of the bed while the liquid traveled radially from the inside to the outside of the rotor. Between the adjacent concentric rings, the gas phase could be fully kept in contact with the dispersed liquid phase in crossflow. The rotor structures and the two-phase flow arrangements determined its potential features, such as the low shaft power and the little backmixing, which, together with stagewise contacting, were favorable to multistage separation processes widely used in chemical process industries. In a pilot CRB, the pressure drop, shaft power, and mass-transfer performance were investigated under different operation conditions. The experimental results showed that the pressure drop, the shaft power, and the efficiency in each theoretical stage fell within the range of 100–600 Pa, 100–250 W, and 10%–15%, respectively. Compared to the rotating zigzag bed (RZB), the CRB generated a lower pressure drop and needed less shaft power for every contacting stage, which can be attributable to its different structures. However, the stage efficiency of the CRB was, at most, one-third as much as that of the RZB. This rather poor mass-transfer performance of the CRB shadowed, to a large degree, its advantages in the pressure drop and shaft power reductions. Therefore, it was necessary to optimize the structures of the CRB and enhance its mass-transfer performance.
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