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Operating Case

Enter your system parameters. Results update automatically.

Steam leaving the drum to the process, in pounds per hour. Everything else in the balance scales from it.
lb/hr

Steam leaving the drum to the process. Feedwater, blowdown, and makeup all scale from it.

Condensate ReturnThe share of the steam that comes back to the feedwater tank as condensate. It displaces makeup pound for pound and carries no solids.
%
Condensate returned to the feedwater tank10,000 lb/hr
M alkalinity of the makeup water as CaCO₃. It concentrates through the feedwater into the drum by cycles; returned condensate carries none.
ppm

As CaCO₃. It concentrates through the feedwater into the drum by cycles.

Drum operating pressure. Sets the saturation temperature the blowdown leaves at, which sets the heat it carries.
psig

Saturated at 352 °F. Sets the heat the blowdown carries.

Fuel to steam efficiency. The blowdown heat is grossed up by it to find the fuel that bought it.
%

Typical firetube and watertube boilers run 75 to 85%. Editable.

Boiler Water AlkalinityBoiler water M alkalinity at these cycles, against the ABMA guideline for the drum pressure entered (700 ppm to 300 psig, stepping down with pressure).
At 20 cycles, as CaCO₃630 ppm of 700 ppm

70 ppm of headroom under the 700 ppm ABMA guideline at 125 psig. Chemistry caps this makeup at 22.2 cycles.

ABMA Boiler Water GuidelineAt 125 psig: 700 ppm M alkalinity, 3,500 ppm TDSReturned condensate carries no alkalinitySilica, TDS, and carryover can bind firstFeedwater datum: 220 °F
Boiler water concentration over feedwater concentration, measured by conductivity or chloride. Blowdown is computed from it, not metered.
×

Main operating lever. Higher cycles cut blowdown until chemistry sets the limit.

Cycles based on feedwater assume returned condensate adds no solids. It does not, but it does carry CO₂ made in the boiler, which acidifies the condensate. The Boiler Savings & Efficiency Calculator quantifies it.

Click on any stream to learn more.

Boiler Mass Balance

All flows are live and update with your inputs.

Operating Conditions
Steam Load
20,000 lb/hr
Condensate Return
50%
Cycles of Concentration
20 ×
Makeup Alkalinity
60 ppm
Operating Pressure
125 psig

Key Results

Primary outputs and operational context based on your inputs.

Annual values at 8,400 operating hours. Fuel priced at the stated efficiency. Makeup at 500 lb/hr per gpm.

Makeup Water Fresh water in: the feedwater the returned condensate does not cover.

22.1 gpm

11.14 M gal/yr

Feedwater the returned condensate does not cover.

Feedwater What the pump must supply: the steam plus the blowdown that leaves with it.

21,053 lb/hr

42.1 gpm

Steam plus the blowdown that leaves with it.

Blowdown The bleed that holds the cycles. It leaves at saturation temperature, so it is a fuel bill before it is a water bill.

1,053 lb/hr

1.06 M gal/yr

Holds the cycles. A fuel bill before it is a water bill.

Boiler Alkalinity Boiler water M alkalinity at these cycles, against the ABMA guideline for the drum pressure entered (700 ppm to 300 psig, stepping down with pressure).

630 ppm

of 700 ppm ABMA

70 ppm of headroom under the guideline.

Heat Lost Sensible heat above the 220 °F feedwater datum, leaving with the blowdown. No flash steam or heat recovery credit is taken.

138,947 Btu/hr

in blowdown at 352 °F

Sensible heat above the 220 °F feedwater.

Fuel Cost The fuel price the blowdown heat is charged at, per million Btu.
$
per MMBtu
Annual Fuel Cost of Blowdown$11,672

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