Our last series of posts have mentioned 2 kinds of boiler blowdown
, "bottom blowdown" and 'surface blowdown". We've discussed what bottom blowdown
is and the correct method of bottom blowing a boiler
. Today, and our next several posts, will focus on "surface blowdown".
While bottom blowdown is used for suspended solids removal, surface blowdown or surface 'skimming' is used to remove dissolved solids from a steam boiler. The boiler feedwater contains dissolved solids consisting of minerals such as:
- chloride and soluble calcium
These minerals become concentrated in the boiler water as steam is generated. High levels of these dissolved solids can result in boiler water carryover into the steam system which may cause severe damage to equipment that uses steam such as steam turbines, heat exchangers and steam traps. Surface blowdown is the method used to remove these dissolved solids.
How are these dissolved solids measured and controlled? Find out in our next blog!