Liquid distribution into packed tower

A MC module contains thousands of microporous hollow fibres, which are knitted into a fabric that is wound around a distribution tube with a central baffle as shown in Figure 1.15. The baffle ensures the water is distributed across the fibres, and also results in reduced pressure drop across the contactor. The hollow fibres are packed densely in a membrane module with a surfrce area of up to 4000 n / m. The liquid flows outside (shell side) the membrane, while vacuum is appHed on the inside of the fibre (tube side) forming a film across the pores of the membrane. Mass transfer takes place through this film and the pores due to the difference in the gas partial pressure between the shell side and tube side. Since the membranes are hydrophobic, they are not wetted by water, thereby, efiectively blocking the flow of water through the membrane pores. The membrane provides no selectivity. Rather its purpose is to keep the gas phase and the Hquid phase separated. In effect, the membrane acts as an inert support that allows intimate contact between gas and liquid phases without dispersion. Vacuum on the tube side of the membrane increases the mass transfer rate as in a vacuum tower. The efficiency of the process is enhanced with the aid of nitrogen sweep gas flowing on the permeate side of the membrane. 

Design and (deration. The design and operation of a typical Manchester plant located in Linacre, Liverpool, is described in detail by Townsend (1953). In this plant, which proce.sses about 3 MMscf gas/day, the gas passes consecutively through six cylindrical absorption towers that are 7 ft 6 in, in diameter by 25 ft in overall height. The towers are packed with wooden boards, and the liquid is distributed in the first two and last two towers by rotating distributors and in the middle two towers by serrated troughs. I h solution is pumped into each... 

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