Process cooling with air as cooling medium is used successfully in many industry branches.
With steadily increasing costs for cooling water it also becomes more and more important in the power industry. At locations where cooling water is not available it is often the only possibility for the cooling of process streams.
In the power industry air cooled condensers (ACC) are used for the condensation of turbine exhaust steam. According the condition of the steam the condensation takes place under vacuum conditions. During that process the heat of condensation is transferred directly to the ambient air. The steam is distributed via a steam duct to the condenser. The condenser consists of the required number of heat exchanger bundles which are arranged on an A-frame construction.
The heat transfer surface is made up of steel tubes with aluminium fins. Each bundle has a condenser-part and an integrated reflux-part. This makes for a reliable condensation of the steam and removal of non-condensables.
The cooling air is conveyed and distributed to the heat exchanger bundles with axial fans in forced draft installation. The required speed reduction from the drive motors to the fans is done with gearboxes.
For smooth operation under varying load conditions the fan speed adjusted with frequency converters according to the required process pressure on the steam side. For demanding load cases, e.g. very low flows of steam and sub-freezing temperatures, the integration of condenser- and reflux-part in the same bundle makes it possible to completely close off parts of the existing heat exchanger surface.
Around the A-frame arrangement of the bundles a wind-wall which is build over the complete height of the frame reduces the influence of wind and prevents air-recirculation. The required vacuum conditions inside the condenser are established with an evacuation unit which is designed according international standards.
The condensate is drained to a condensate tank through collectors and the connecting pipework. Condensate pumps convey the condenser water to the feed water tank or the water treatment unit.
The Standard Air Cooled Condenser is an A-Frame design. The finned single tube bundles are mounted above of the forced draught axial fan on a steel structure in the form of an A.