PSA vs. VPSA / Vacuum-Cycle Oxygen Generators for Biogas
Not every on-site oxygen generator behaves the same at the outlet. This page compares conventional PSA generators with ON2's patented vacuum-cycle plants on the numbers that decide your operating cost and reliability — usable output, electricity draw, air drying, and delivery pressure — using specifications you can verify on site.
Usable output: 100% vs. 60–70%
A conventional PSA plant consumes roughly 30–40% of the oxygen it produces just to keep running, so it delivers only 60–70% of its rated output to your process. ON2's patented vacuum-cycle plant delivers 100% of rated output — nothing is spent keeping the plant running. That difference shows up directly at your flow meter.
Electricity: 20–40% less
ON2 vacuum-cycle plants use 20–40% less electricity than a typical PSA plant to deliver the same oxygen to your process. Electricity is the main operating input for on-site generation, so a lower draw compounds every hour the plant runs. You can verify it at your power meter.
No air dryer, no pressure booster
Conventional PSA generators typically require an air dryer to protect the sieve bed and often need a pressure booster to reach a usable outlet pressure. ON2 plants need neither: delivery pressure is adjustable from 0 to 50 psi natively — full delivery pressure with no booster — and a vacuum sweep purges heat, humidity, and contaminants every 100 seconds, so there is no separate air dryer to maintain. The self-cleaning sieve bed has run 20+ years in the field without replacement.
Outcome-only, verifiable claims
Every comparison on this page is a measurable outcome, not a lab number: usable output at your flow meter, electricity at your power meter, and delivery pressure at your outlet. ON2 systems deliver 90–95% oxygen purity for biological desulfurization, ship with hospital-grade remote monitoring for purity, CO₂, temperature, and contamination alerts, and are manufactured in the USA in an ISO 13485 facility, designed to NFPA 99.
What's included
- Delivers 100% of rated output — PSA delivers only 60–70%
- 20–40% less electricity than a typical PSA plant
- No air dryer to maintain; vacuum sweep purges every 100 seconds
- Full delivery pressure natively, 0–50 psi — no booster
- Self-cleaning sieve bed: 20+ years in the field without replacement
- 90–95% purity; hospital-grade remote monitoring
Frequently asked questions
How is a vacuum-cycle plant different from a conventional PSA generator at the outlet?
A conventional PSA plant consumes roughly 30–40% of its own oxygen to keep running and delivers only 60–70% of rated output, typically needs an air dryer, and often needs a pressure booster. An ON2 vacuum-cycle plant delivers 100% of rated output, uses 20–40% less electricity, needs no air dryer, and reaches full delivery pressure natively — all verifiable at your flow meter, power meter, and outlet.
Does the vacuum-cycle plant need an air dryer?
No. A vacuum sweep purges heat, humidity, and contaminants out of the system every 100 seconds, so there is no separate air dryer to install or maintain.
What purity and pressure does an ON2 plant deliver?
ON2 plants deliver 90–95% oxygen purity — the range typically specified for biological desulfurization — with delivery pressure adjustable from 0 to 50 psi, reached natively without a booster.
Where are ON2 oxygen plants built?
Every ON2 system is manufactured in the USA in an ISO 13485 facility, designed to NFPA 99, with US-based support. ON2 has been building oxygen systems since 1984.
Compare the outlet numbers for your site
Tell us your oxygen demand and we'll spec a vacuum-cycle plant with the output, electricity, and delivery pressure you can verify — purchase or lease-to-own.