A second mode of operating packed columns and wetted wall columns

For a fixed set of gas and liquid rates below the flooding flow rates in a wetted wall column and a packed column, two modes of operation are possible, viz., normal and incipient flooding. The latter has not been reported previously. Methods for stabilizing this mode of operation are described. Both modes can coexist in different sections of the same column. Modification to industrial packed towers to permit operation in the incipient flooding mode are simple and inexpensive. Such modifications permit operation with higher liquid holdup and higher mass transfer rates at the expense of higher pressure losses