The vertically standing tube is equipped inside with fittings enabling intensive contact between washings and clean exhaust. The choice of the installations depends on the respective cleaning task and the composition of the exhaust gas.
Gas and washing travel through a counter-flow scrubbing column. In doing so, the exhaust gas to be cleaned enters sideways at the lower end of the column and is led upwards to the upper end of the column. The washing liquor is distributed over the entire tube cross-section and trickles down along the column internals, where it is collected in a container.
In the case of a physical absorption, the scrubbing liquor lead through the column tube in one single pass. In the case of a chemical absorption, the scrubbing liquid is circulated through a centrifugal pump. Occurring wastewater is separated in the container via an overflow or via level controlled pump.
The counter-flow arrangement results in a maximum exploitation of the concentration difference between exhaust gas and scrubbing fluid which is an important motive factor for absorption. The maximum cleaning effect is achieved as a factor of the column height.
The naming of the column type depends on the kind of column internals. A distinction is made between:
- packed-bed columns
- packed columns
- plate columns
- spray columns
Depending on the requirement each column type can be combined with any GEA Wiegand scrubber type.