No heat extraction from flue gases

No heat extraction from flue gases

No heat extraction from flue gases

The condensate from the system will be passed directly to the deaerator (see figure below). The steam required for deaeration and to heat up the condensate to the minimum required temperature for the boiler is taken from an externally available steam source (e.g. LP steam).

The efficiency of this set-up is rather low so it is not commonly used as a solution. If however the condensate temperature from the process or condenser is sufficiently high, then this set up may offer itself as a useful option.

Example:

A district heating plant has return condensate coming from the LP district heating condenser at 60°C which is heated up in the deaerator to 65°C (this can be safely done as the fuel used for firing is natural gas containing no sulfur). Low pressure steam from the steam turbine is used as the heating medium. Obviously, the deaerator operates under vacuum conditions.