Illustrative worked example. The inputs are assumptions, not a customer project. The arithmetic is real.
The scenario
A food manufacturer runs three packaging lines on cylinder nitrogen. Together they use 40 Nm³/h for 16 hours a day.
| Input | Value |
|---|---|
| Total nitrogen flow | 40 Nm³/h |
| Operating time | 16 hours a day |
| Purity | 99.5% |
| Delivery pressure | 7 bar |
What that means in cylinders
Daily use is 40 × 16 = 640 Nm³. A 50-litre cylinder at 200 bar holds roughly 9 to 10 Nm³, so the lines consume about 65 to 70 cylinders a day. Each one is received, moved, connected and returned.
Choosing the technology
- Flow. 40 Nm³/h is inside twin-tower PSA's range of 5 to 5,000 Nm³/h. It is also inside modular PSA's range of 10 to 50 Nm³/h, but with a 25% margin the rated flow reaches the top of that range.
- Purity. 99.5% is the top of Eldtek's membrane range (up to 99.5%). PSA, which reaches up to 99.999%, leaves headroom.
- Result. Twin-tower PSA is chosen here because the margin takes the rated flow to the limit of the modular range and leaves no room for growth. A modular skid is the alternative if fast commissioning matters more.
Specification to request a quotation
| Item | Value |
|---|---|
| Technology | Twin-tower PSA |
| Rated flow | 50 Nm³/h (40 Nm³/h plus 25% margin) |
| Purity | 99.5% |
| Pressure | 7 bar |
| Air supply | Compressor and dryer sized with the plant |
What Eldtek confirms
- Compressed air demand at 99.5% purity and the compressor size.
- Purity at the rated flow.
- Buffer storage for peak demand.
- Power, footprint and installation.
See the nitrogen generation plants page for the full range.
Frequently asked questions
How many cylinders does 40 Nm³/h replace?
About 65 to 70 cylinders a day at 16 hours of use, assuming a 50-litre cylinder at 200 bar holds 9 to 10 Nm³.
Why add 25% margin to the flow?
Demand tends to grow and lines get added, and a margin avoids running the plant at its limit. The right margin depends on how steady the demand is.
Have a similar requirement?Send your figures and an Eldtek engineer will size it for your site.
Request a quotation