Boiler Blowdown Rate & Cycles Calculator
Compute boiler continuous surface blowdown rate, cycles of concentration (COC), blowdown thermal energy losses, and heat recovery savings per ABMA standards.
Boiler Steam Load & Pressures
Boiler Water Quality Limits
Blowdown & Heat Recovery Analysis
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Frequently Asked Questions
What is the purpose of surface continuous boiler blowdown?
As pure steam boils off inside the boiler, dissolved solids (salts, silica, minerals) remain behind and concentrate in the drum. Continuous surface blowdown skims off the most concentrated high-TDS water from near the water surface, preventing foaming, priming, and scale formation.
What is Cycles of Concentration (COC) in a steam boiler?
Cycles of concentration (COC) is the ratio of dissolved solids in the boiler water to the dissolved solids in incoming feedwater (COC = Boiler TDS / Feedwater TDS). Higher cycles mean less heated water is dumped down the drain, conserving fuel and expensive water treatment chemicals.
How does a blowdown heat recovery system save energy?
A heat recovery system passes high-pressure blowdown water through a flash tank to generate low-pressure flash steam for the deaerator, and then sends the residual drain through a shell-and-tube heat exchanger to preheat cold makeup water, recovering over 70% of wasted heat.