Studies On Hydrodynamic Characteristics Of Rotating Zigzag Bed

As a new and efficient gas-liquid contactor, Rotating Packed Bed can greatly increase the gas-liquid specific interfacial area and intensify the process of mass transfer using centrifugal field to replace the gravitational field. Rotating zigzag bed (RZB) is a new type of contactor which has been applied in the industrialization of distillation process with dozens of system. The rotor of RZB consists of stationary discs and rotating discs. Hydrodynamics of RZB, including the liquid hold-up, entrainment, pressure drop and flooding have been investigated experimentally using air-water in this paper. Influences of the liquid superficial velocity uL, the gas superficial velocity uG and the super gravity factor β on the liquid hold-up, entrainment, pressure drop and flooding of RZB were investigated. And a mathematical model of liquid hold-up was proposed originally. Effects of surface tension and liquid density on entrainment of RZB were also investigated using volume fraction 3%,6% of ethanol solution and mass fraction 20%,30% of potassium carbonate solution.The experimental results show that:(1) The liquid hold-up of RZB increases with increased liquid superficial velocity uL and gas superficial velocity uG, but decreases with increased super gravity factor, and the influence of the uG decreases significantly at the high rotor speed.(2) Firstly the pressure drop increased slowly, and then increased rapidly, when the uG increased. The flooding point appeared after the pressure drop curve inflection point.(3) Firstly the pressure drop of RZB increased slowly, and then increased rapidly, when the liquid superficial velocity uL increased. After the flooding point appeared the pressure drop raised gently. In particular, the pressure drop increased linearly with the increased uL when the gas superficial velocity uG was 1.23m/s.(4) The pressure drop of RZB increased firstly, and then decreased rapidly after the flooding appeared, when the super gravity factor β increased. When the super gravity factor was above 120 the pressure drop raised modestly.(5) The entrainment increased when the gas superficial velocity uG and the liquid superficial velocity uL increased. And firstly the entrainment of RZB decreased rapidly, and then increased slowly, when the super gravity factor increased.(6) The surface tension and liquid density can intensify the entrainment of RZB.