Boiler blowdown pumping is a unique application in terms of pump design with its own set of challenges. The blowdown water is at elevated temperature (typically > 90 deg C), it may contain small solids, and the pumping is a transfer duty requirement (i.e.) the pumping needs to be done periodically for transferring the blowdown water to the effluent pit. Typically, the blowdown water from the boiler is emptied into a pit of depth exceeding 5-6 metres and it needs to be pumped from this pit to the effluent pit. Operators often opt for a vertical sump pump to achieve the pumping. However, conventional vertical sump pumps have reliability issues since at 5-6 m depths, the pumps need to have intermediate supports which clog and seize the pump due to the small solids content. Additionally, with a deviation from the designed duty condition, the pump starts giving trouble since long shaft impeller assembly needs to handle the imbalanced radial thrust on the pump which results in deflection of the entire rotating shaft assembly. Operators who use vertical pumps for blowdown application certify that their biggest headache in vertical pumps is the wear and tear associated with the rotating parts, especially the wet bearings. With the new tested and proven design of the vertical pump, it truly becomes a fit and forget (or rather fit and remember) pump.
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