Boiler Blowdown Rate

A blowdown of the boiler is a routine operation necessary due to the increased concentration of Total Dissolved Solids - TDS - in the boiler water when producing steam.

The blow down rate of a boiler depends on

• steam consumption (steam used in the process and not returned as condensate to the boiler)
• concentration of impurities in the feed water
• maximum allowable TDS in the boiler

The blowdown rate can be calculated as

q_BD= q_S f_c / (b_c - f_c)                                        (1)

where

q_BD = blowdown rate (kg/h)

q_S = steam consumption (kg/h)

f_c = Total Dissolved Solids - TDS - in the feed water (ppm)

b_c = maximum allowable Total Dissolved Solids - TDS - in the boiler water (ppm)