In Direct Contact Flue Gas Condenser, a cooled liquid is frequently recirculated through an external heat exchanger to remove the heat of condensation and sensible heat picked up from the gas by the liquid.
Within the flue gas condenser itself, intimate mixing and contact is brought about between the liquid and gas to effect a thermal and mass transfer equilibrium.
The cold liquid may be sprayed onto the gas in a spray tower or jet eductor, or a tower with gas-liquid contactors. The contacting tower can be a packed tower, sieve plate tower, or a segmented baffle plate tower.
Since liquid becomes heated by both the gas and condensing vapour, lower dew points can be reached with counterflow of liquid and vapour, but many parallel flow devices are also in existence.