Rotating zigzag bed as trayed HIGEE and its power consumption

High gravity (HIGEE) technology, which uses centrifugal force to intensify mass transfer, has been applied to chemical processing industries. A rotating packed bed is a conventional HIGEE with a rotor filled with packings. A rotating zigzag bed (RZB) is a novel HIGEE with a rotor containing coupled rotational-stationary baffles as discrete steps, which are called HIGEE trays, to provide gas-liquid contact. RZB power consumption is mainly the power requirement for liquid flow. With the ideal liquid flow in an RZB rotor, this study develops a model that can predict the power requirement for ideal liquid flow at zero gas flow. The power requirement for liquid flow is equal to the model-predicted power requirement multiplied by two departure coefficients of real liquid and gas. Experiments were performed in two RZBs by using air-water system, and the consumption with gas rate, liquid rate, and rotational speed was measured. The departure coefficient of real liquid increased with increasing liquid rate and rotational speed, and its value at the greatest liquid rate ranged from 1.14 to 1.28 at various rotational speeds. The departure coefficient of gas increased with increasing gas rate and decreased with increasing liquid rate and rotational speed. The value of the departure coefficient of gas at the greater gas rate ranged from 1.36 to 2.80 at various liquid rates and rotational speeds. The power requirement for liquid flow in RZB was approximately 2.5 times as that of rotating packed bed, so the RZB power consumption should be given more attention. (C) 2012 Curtin University of Technology and John Wiley & Sons, Ltd.