Glass furnaces burn fuel to melt silica sand at very high temperatures. Burning that fuel with oxygen instead of air, known as oxy-fuel or oxygen-enriched combustion, gives a hotter flame, uses less fuel, and cuts NOx emissions, because there is far less nitrogen in the furnace. A PSA oxygen generator supplies 90–95% oxygen on site, so glassworks get these gains without depending on liquid oxygen deliveries.
This guide explains how oxygen is used in glass production, what PSA oxygen offers over liquid oxygen and cryogenic plants, and what to check when choosing a generator.
How oxygen is used in glass production
- Oxy-fuel melting: fuel is burned with oxygen instead of air. Without the 78% nitrogen in air soaking up heat, the flame is hotter and more of the energy goes into the glass.
- Oxygen enrichment: extra oxygen is added to the combustion air of an existing air-fuel furnace to raise output without a full rebuild.
- Melting and fining: a stable, hot furnace helps release bubbles and dissolved gases, improving glass quality.
- Burners for forming and finishing: oxy-fuel burners are used where precise, high-temperature heat is needed.
Benefits of oxygen-fuel combustion
- Lower fuel use: less heat is wasted warming nitrogen and carrying it up the stack.
- Lower NOx: with little nitrogen in the furnace, far less NOx forms.
- Smaller flue gas volume: less gas to treat and less heat lost in the exhaust.
- Higher output and quality: hotter, more stable melting.
Why make oxygen on site with PSA?
Glassworks traditionally bought liquid or cylinder oxygen. That brings transport costs, price changes, supply disruptions and the risk of running out. An on-site PSA oxygen generator:
- Produces oxygen continuously at the furnace, with no deliveries.
- Delivers 90–95% purity, which suits combustion.
- Scales with production, and buffer storage handles changes in demand.
- Costs much less per Nm³ than liquid oxygen. See comparison of the cost of oxygen from different sources.
PSA vs cryogenic oxygen for glassworks
| Parameter | PSA oxygen | Cryogenic oxygen |
|---|---|---|
| Purity | Up to about 95% | Up to 99.5% and above |
| Capital cost | Lower | Much higher |
| Footprint | Small | Large site and storage tanks |
| Installation | Simple, skid-mounted | Complex |
| Capacity | Flexible, modular | Fixed, suited to very large volumes |
| Start-up | Minutes | Hours |
For very large furnaces, VPSA (vacuum pressure swing adsorption) can lower the power per Nm³ further. Cryogenic plants make sense mainly where very large volumes or liquid oxygen are needed.
How a PSA oxygen generator works
Compressed air is filtered and dried, then passed through towers of zeolite molecular sieve. Zeolite holds nitrogen and lets oxygen through to a buffer tank. Two towers alternate between making oxygen and releasing the trapped nitrogen, so supply is continuous. A PLC runs the cycle, and an analyser monitors purity. Read the PSA oxygen generator engineering guide for full details.
What to check when choosing a generator
- Flow and purity for your furnaces and burners, including peak demand.
- Power per Nm³: the air compressor is the main running cost.
- Turndown and storage: how the plant handles changes in demand.
- Purity monitoring and records for process control.
- Reliability and service: response time, spares and a long sieve warranty.
- Customisation for your site, pressure and layout.
Safety
Install the plant and pipework correctly, leak-test oxygen lines, ventilate the plant room, monitor purity, and train operators to handle oxygen safely.
Talk to us about your furnace
See Idos industrial oxygen generators (1–5,000 Nm³/hr). Email info@absstem.com or call 1800 547 0506.