Illustrative worked example. The inputs are assumptions, not a customer project. The arithmetic is real.
The scenario
A cement kiln releases 100,000 Nm³/h of flue gas containing 20% CO₂ by volume. Cement kilns commonly emit about 14 to 33%.
CO₂ in the flue gas
CO₂ flow is 100,000 × 20% = 20,000 Nm³/h. At about 1.977 kg/Nm³ that is roughly 39.5 tonnes of CO₂ each hour.
CO₂ captured at three capture rates
| Capture rate | Per hour | Per day | Per year |
|---|---|---|---|
| 60% | 23.7 t | 569 t | 190 kt |
| 75% | 29.7 t | 712 t | 237 kt |
| 90% | 35.6 t | 854 t | 285 kt |
What decides the real number
- Capture rate against purity. Pushing both up needs more stages, area and compression, so energy use rises.
- CO₂ concentration. Richer streams are easier for membranes.
- Contaminants. Dust, acid gases and water need treatment before the membranes.
- What happens next. Utilisation or storage sets the delivery pressure.
See the CO₂ capture systems page for how the technology works and what we need to size a system.
Frequently asked questions
How much CO₂ is in 100,000 Nm³/h of flue gas at 20%?
About 20,000 Nm³/h of CO₂, or roughly 39.5 tonnes an hour at 1.977 kg/Nm³.
Is 90% capture guaranteed?
No. Eldtek states that up to about 90% is achievable. The rate for a site depends on gas composition, the number of stages and the purity needed.
Have a similar requirement?Send your figures and an Eldtek engineer will size it for your site.
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