Boiler CO2 Generation Rule of Thumb

Field estimate of carbon dioxide generated in steam and condensate from feedwater alkalinity, used to budget neutralizing amine demand and acid feed. Not a universal stoichiometric law; actual generation depends on pressure, alkalinity form, cycles, steam purity, and operating conditions.

$$\mathrm{C}{\mathrm{O}}_2(\mathrm{ppm})\approx 0.79\times {\text{M-alkalinity (ppm as CaCO}}_3)$$

Variables

Symbol	Meaning	Unit
$C{O}_2$	carbon dioxide generated in steam or condensate	ppm
0.79	empirical conversion factor	ppm CO2 per ppm alk
M-alkalinity	total feedwater alkalinity as CaCO3	ppm as CaCO3

Worked example

100 ppm M-alkalinity as CaCO3 in feedwater produces about 79 ppm CO2 in steam and condensate.

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Part of The Blueprint of Water