Bottom Blowdown in Boiler

Bottom blowdown in boilers is used to remove impurities which have fallen to the bottom as precipitates.  These impurities are in the solid phase.  Bottom blowdown is done by means of a valve connected to the bottom of the valve.  When the valve is opened, the impurities are flushed out by the boiler pressure.

The steam collected during the blowdown can be removed into a steam flasher and a heat exchanger.  The heat can be recovered and the steam can be recirculated after passing through the flash tank and the deaerator.

The duration and frequency of the blowdown is determined on factors such as size of the boiler, water quality and the location and the operating load.

A proper blowdown programme improves efficiency and reduces maintenance costs.