A Plate Column (or Tray Column) is a chemical equipment used to carry out unit operations where it is necessary to transfer mass between a liquid phase and a gas phase.
The peculiarity of this gas-liquid contactor is that the gas comes in contact with liquid through different stages; each stage is delimited by two plates (except the stage at the top of the column and the stage at the bottom of the column).
Plate towers consist of a vertical column with liquid flowing in the top and out the bottom. The vapor phase enters in the bottom of the column and exits out of the top.
Inside of the column are trays or plates. These trays force the liquid to flow back and forth horizontally while the vapor bubbles up through holes in the trays.
The purpose of these trays is to increase the amount of contact area between the liquid and vapor phases. Some common applications of plate columns are distillation, gas-liquid absorption and liquid-liquid extraction.
In general, plate columns are suitable for both continuous and batch operations.