Hydrodynamics and design of gas distributor in large-scale amine absorbers using computational fluid dynamics

A gas phase three-dimensional (3D) computational fluid dynamics (CFD) model was developed to investigate the hydrodynamics of gas distributors used in an amine absorber with a diameter of 3.2 m. A standard gas inlet, tubular injectors with short, medium and long lengths, and a Schoepentoeter were considered as feed systems of the gas distributors. The pressure drop, dead-area ratio and coefficient of distribution at the packing entry were used as the performance indexes of the gas distributors. The down-pipe as a liquid collector exhibited a lower dead-area ratio when compared with that of the down-comer. The tubular gas injector with a short length reduced the dead-area ratio and the gas maldistribution. The Schoepentoeter was associated with the lowest pressure drop, dead-area ratio, and coefficient of distribution among the gas distributors. The uniformity of gas distribution was enhanced by 25% in the Schoepentoeter when compared to that of the tubular gas injector.