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Study on Performance of Fluid Dynamics and Mass Transfer of Rotating Bed in High-gravity

Author: BaoTieHu
Tutor: JiJianBing
School: Zhejiang University of Technology
Course: Chemical Engineering
Keywords: High gravity field Rotating bed Gas - liquid mass transfer Pressure drop
CLC: TQ021
Type: Master's thesis
Year: 2002
Downloads: 375
Quote: 11
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Abstract

Rotating packed bed was developed in the early eighties, a new type of high gravity field gas-liquid mass transfer equipment. It is much larger than gravity, centrifugal force, generated by the rotation of the use of the gas-liquid contact in a high degree of turbulence, enhancing mass transfer process and improve the efficiency of mass transfer. Since the 1980s, domestic and abroad companies and universities rotating packed bed, the study includes filler improved fluid dynamics and mass transfer performance aspects. This article is Zhejiang University, based on the research of rotating packed bed gas pressure drop through the improvement of the structure of the rotor, further research on the mass transfer efficiency of the two different types of rotating bed, the gas pressure drop, and the initial establishment of the rotation Bed and mass transfer model. This article is designed rotor structure of a gas-liquid contact, appropriate residence time baffled. Such a structure is installed within the rotor annular baffle sheet, a certain gap is left between the upper and lower baffle plates, wherein the upper baffle plate is fixed, the lower baffle plate is rotated together with the rotor, so that the flow of liquid from the inside outwardly in the rotor the process of constantly being pulverized, atomized, increased gas-liquid contact area and surface renewal frequency; gas-liquid counterflow bypassing the interleaved baffles appropriate increase in the residence time of the gas-liquid in the rotor, thereby significantly improve the pass transfer efficiency. Under conditions of atmospheric pressure, the total reflux, a speed of 400 ~ 1200rpm to ethanol - water system, the pressure drop and the mass transfer efficiency of the rotating bed conducted. Trials were changed the size of the amount of the reflux liquid and the rotor rotational speed, measuring the ethanol concentration of the top of the reflux liquid, the concentration of ethanol within the bottom reboiler and through rotating bed of gas pressure drop. The gas pressure drop correlations on the rotation speed, gas-liquid flow; mass transfer efficiency with speed, back flow changes the relationship, and the initial establishment of a theoretical model of the mass transfer efficiency. To change the structure of the rotor of the rotating bed, under the same operating conditions, the pressure drop and the mass transfer efficiency. These changes include: (1) to expand the outer diameter of the rotor, the rotor and down the number of baffle plates is increased by 50%; (2) of the rotor on the baffle plate and lower baffle plates together with the rotation of the rotor; (3) in the deflector cubicle filled with Raschig rings. The experimental results show that: 1. In the same gas-liquid flow rate, the greater the rotational speed of the rotating bed, the higher its mass transfer efficiency; 2. In a fixed speed, the mass transfer efficiency of the rotating bed, the increase of the gas-liquid flow rate decreased slightly, but remained at a constant value; 3. Baffled rotating bed gas pressure drop increases as speed and gas-liquid flow increases; the rotating packed Zhejiang Industrial University, a master's degree abstracts bed gas pressure drop with increasing speed and gas flow rate increases, with the with liquid flow decreases. 4. In the liquid flow rate is 251 / h, the rotational speed of 1200r/min under operating conditions, the rotor diameter 500mm Baffled rotating bed can be obtained 9.8 theoretical plates of the separation effect, the number of equivalent to 49 theoretical plates per meter ; 5. Between the baffle fill Raschig rings rotating zigzag bed mass transfer efficiency is much lower than the mass transfer efficiency of rotating zigzag bed. Using a digital camera in the experiment also transferred to the imaging of the high-speed rotation of the deflector plate, in the case of a very short exposure time, the instant image has been transferred to the movement of the liquid inside, thus observed that the liquid inside the rotor to be crushed into tiny the phenomenon of the droplets.

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CLC: > Industrial Technology > Chemical Industry > General issues > Chemical processes ( physical processes and physical and chemical processes ) > Basic theory
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