close
Choose Your Site
Global
Social Media
Modern glass plants operate under intense pressure to reduce energy costs, lower emissions, and deliver flawless glass quality. Combustion is at the heart of this process, and combustion depends on oxygen. Traditionally, that oxygen has come from bulk liquid deliveries or compressed cylinders. Today, however, more and more glass manufacturers are turning to on-site Oxygen generator systems as a flexible, cost-effective way to feed oxy-fuel furnaces and oxygen-enriched air-fuel burners.
In practice, using an on-site industrial Oxygen generator for glass production allows plants to secure a continuous, high-purity oxygen supply, increase furnace efficiency, reduce fuel consumption and NOx emissions, and improve glass quality, all while gaining long-term cost control and independence from external gas deliveries.
The shift from conventional air-fuel combustion to oxy-fuel or oxygen-enriched firing has been ongoing since the 1990s, as glass producers realized that pure oxygen dramatically boosts flame temperature, improves heat transfer, and makes regenerators unnecessary in many cases. Today, oxy-fuel technologies can cut fuel consumption by around 25–30 percent and reduce NOx emissions by up to 60–90 percent in well-designed systems, depending on furnace type and operating conditions. An on-site Oxygen generator is the enabling backbone for these gains, ensuring that oxygen is always available at the purity, pressure, and flow rate the furnace requires.
To understand how to specify and deploy an Oxygen generator for glass production, it helps to look at the role of oxygen in glass melting, the core technologies behind Oxygen generator systems, the key sizing and design parameters, and how these systems compare with traditional oxygen supply methods. The following guide walks through each of these topics from a practical, engineering-oriented perspective for plant managers, maintenance teams, and project engineers.
Why Glass Production Needs High-Purity Oxygen
How an Oxygen Generator Supports Glass Furnaces
Main Oxygen Generator Technologies for Glass Plants
Key Specifications When Selecting an Oxygen Generator
Cost and Performance: Oxygen Generator vs. Liquid Oxygen and Cylinders
Integration of an Oxygen Generator into Glass Production Lines
Operation, Safety, and Maintenance Best Practices
Conclusion
Glass production needs high-purity oxygen from an industrial Oxygen generator to increase flame temperature, improve heat transfer, reduce fuel use, and minimize defects and emissions compared with traditional air-fuel combustion.
Glass furnaces operate at extremely high temperatures, often above 1500°C, to melt silica and other raw materials into a homogeneous glass melt. With conventional air-fuel combustion, only around 21 percent of the oxidant is oxygen, while the remaining 79 percent is nitrogen that must be heated and then exhausted, using energy without contributing to combustion. By supplying high-purity oxygen from an Oxygen generator, the furnace can eliminate most of this nitrogen ballast, creating a hotter, more concentrated flame and significantly improving melting efficiency.
Higher oxygen concentration leads to more efficient combustion and better control over the temperature profile within the furnace. This results in more uniform melting, shorter refining times, and fewer defects such as stones and cords. Glass producers using oxy-fuel or oxygen-enriched air-fuel firing commonly report improved glass clarity and consistency when they stabilize their oxygen supply with an on-site Oxygen generator.
There is also a strong environmental driver. Air-fuel furnaces generate considerable NOx because high flame temperatures and nitrogen from the combustion air promote NOx formation. By replacing air with oxygen from an Oxygen generator, flue gas volumes decrease, flame temperature can be controlled more precisely, and NOx formation is lower for the same pull rate. Studies and industrial case histories show reductions in NOx emissions of 60 percent or more when oxy-fuel or oxygen-enriched technologies are used correctly.
Finally, high-purity oxygen from a dedicated Oxygen generator provides flexibility. Plants can boost production during peak demand by increasing oxygen flow, or adjust enrichment profiles to balance fuel savings and emissions performance. This is far easier and more responsive than trying to scale deliveries of liquid oxygen or cylinders, especially for large continuous furnaces.
An Oxygen generator supports glass furnaces by producing a continuous stream of high-purity oxygen on site, feeding oxy-fuel burners, oxygen-enriched air-fuel systems, and ancillary processes without relying on external gas deliveries.
A typical industrial Oxygen generator for glass production is based on Pressure Swing Adsorption (PSA) or Vacuum Pressure Swing Adsorption (VPSA) technology. Ambient air is compressed, dried, and passed through molecular sieve beds that selectively adsorb nitrogen, allowing oxygen to pass through. By cycling the beds between pressurization and depressurization, the Oxygen generator delivers a steady flow of oxygen with typical purity around 90–95 percent, often specified as about 93 ± 1 or 2 percent for industrial applications.
For a glass plant, the Oxygen generator generally sits in a dedicated utility area and consists of several integrated modules: air compressor, air treatment (filters, dryer), buffer tanks, the PSA or VPSA Oxygen generator skid, oxygen storage tanks, and control and monitoring systems. Many suppliers offer containerized Oxygen generator packages with all components mounted inside a standard shipping container for easy installation, relocation, and weather protection.
Once installed, the Oxygen generator supplies oxygen at controlled purity, pressure, and flow rate to the furnace system. Depending on the design, oxygen may go directly to oxy-fuel burners, to oxygen-enriched air burners (via mixing with combustion air), or to lances for oxygen-enhanced NOx reduction. It can also serve secondary uses around the plant such as cutting, welding, or waste gas treatment. The uptime of the Oxygen generator is typically very high, and many systems are designed for 24/7 operation to match the continuous duty of container or float glass furnaces.
For process engineers, the key benefit is control. With a properly sized Oxygen generator, operators can fine-tune oxygen enrichment levels, modify burner stoichiometry, and adjust temperature profiles in response to pull rate changes or product specifications. This level of control is particularly valuable when producing high-value glass types where quality and consistency are paramount.
The main Oxygen generator technologies for glass plants are PSA Oxygen generator systems and VPSA Oxygen generator systems, with cryogenic plants used only in very large installations.
PSA-based Oxygen generator solutions are the most common choice for small to medium glass plants and for oxy-fuel boosting of existing air-fuel furnaces. PSA Oxygen generator units typically provide oxygen purities around 90–95 percent at flows from a few Nm³/h up to several hundred Nm³/h, which is adequate for many oxy-fuel and oxygen-enriched combustion applications. The equipment footprint is compact, and systems can be skid-mounted or containerized for rapid deployment.
VPSA Oxygen generator systems operate at lower pressure but use vacuum on the desorption step to reduce energy consumption, making them attractive for higher capacities. They are often chosen when the plant requires large volumes of oxygen around the clock and where electricity costs are a major concern. VPSA Oxygen generator installations usually involve multiple large adsorber beds, blowers, and vacuum pumps, and they can deliver oxygen flows in the thousands of Nm³/h range.
Cryogenic air separation units are sometimes considered in very large glass complexes or integrated industrial sites where multiple gases are needed at very high volumes. However, for standalone glass plants, the capital cost and complexity of cryogenic plants are often prohibitive. In these cases, a PSA or VPSA Oxygen generator provides a simpler, more modular supply option.
A simplified comparison is shown below:
| Oxygen supply option | Typical purity | Capacity range (Nm³/h) | Relative capex | Relative opex | Suitability for glass |
|---|---|---|---|---|---|
| PSA Oxygen generator | ~93% | 5–600 | Medium | Low–medium | Small to medium furnaces, oxy-fuel boosting |
| VPSA Oxygen generator | ~93% | 300–3000+ | Medium–high | Low | Large continuous furnaces, multi-furnace sites |
| Cryogenic plant | 99.5%+ | 500–10000+ | High | Medium | Very large complexes with multi-gas needs |
For most container, tableware, and specialty glass producers, PSA or VPSA Oxygen generator systems strike the best balance between purity, cost, and operational flexibility.
Selecting an Oxygen generator for glass production requires careful evaluation of required oxygen flow, purity, pressure, turndown, energy consumption, footprint, and automation to match furnace demand and long-term production strategy.
The first parameter to define is oxygen flow rate. This depends on furnace size, pull rate, combustion mode (full oxy-fuel vs. oxygen-enriched air-fuel), and the desired level of boosting. Engineering guidelines and burner supplier recommendations are normally used to estimate the Nm³/h of oxygen required per ton of glass pulled. From there, the Oxygen generator capacity is sized with a margin for future production increases and maintenance flexibility.
Purity is the next critical parameter. Most glass melting applications can operate effectively with around 90–95 percent oxygen purity from a PSA or VPSA Oxygen generator. Higher purities are technically possible but often deliver diminishing returns relative to the extra energy and capital cost. For many plants, specifying roughly 93 ± 2 percent purity provides an optimal balance between performance and efficiency. Dew point and contamination control are also important; typical Oxygen generator systems deliver oxygen with a low dew point (for example, below −40°C) to avoid moisture-related corrosion and burner issues.
Pressure and distribution must be considered together. Oxy-fuel burners and lances require oxygen at specific pressures; if the Oxygen generator delivers lower pressure, booster compressors may be needed. The piping network from the Oxygen generator to furnaces should be designed for minimal pressure drop and equipped with appropriate isolation valves, non-return valves, and safety devices.
Energy efficiency is another key specification. Glass plants are heavy energy users, and the electricity consumed by the Oxygen generator contributes to overall operating costs. Vendors typically provide specific energy consumption figures (kWh per Nm³ of oxygen). Comparing these against projected operating hours and electricity tariffs allows a realistic calculation of lifecycle cost.
Finally, automation and control features can make day-to-day operation much easier. Modern Oxygen generator packages offer PLC-based automatic control, remote monitoring, oxygen purity and flow alarms, and integration into the plant’s SCADA or DCS. Such features help ensure that the Oxygen generator tracks furnace load and alerts operators to any deviations before they affect production.
Compared with liquid oxygen and cylinders, an on-site Oxygen generator offers lower long-term operating cost, greater supply security, and better alignment with continuous glass production, especially at medium to high consumption levels.
Traditionally, many glass manufacturers have purchased oxygen in the form of delivered liquid oxygen (LOX) stored in onsite cryogenic tanks, or as high-pressure cylinders for smaller applications. While this approach requires low capital investment, the long-term cost per Nm³ of oxygen can be significant once delivery, tank rental, evaporation losses, and supplier margins are included. Transport disruptions and price volatility further complicate planning.
An industrial Oxygen generator in contrast requires a higher upfront capital investment but produces oxygen from ambient air, converting electricity and maintenance into a predictable, internal cost. Over time, especially for plants that operate continuously, this often results in a lower cost per Nm³ compared with delivered LOX or cylinders. Industry data and case studies frequently report payback periods of two to four years for suitably sized Oxygen generator installations.
A practical way to evaluate options is to compare them across key dimensions:
| Parameter | On-site Oxygen generator | Liquid oxygen supply | Cylinder oxygen supply |
|---|---|---|---|
| Supply mode | Produced on site from air | Delivered by tanker | Delivered in cylinders |
| Typical cost trend | Higher capex, lower opex | Low capex, higher opex | Low capex, highest opex |
| Best scale | Medium to large continuous demand | Medium to very large demand | Small, intermittent demand |
| Supply security | High (independent of deliveries) | Dependent on logistics | Highly dependent on logistics |
| Flexibility | Adjustable output, easy scaling by adding units | Step changes by adding tanks and contracts | Limited; manual handling required |
| Glass plant fit | Excellent for continuous furnaces and boosting | Good for large plants; cost sensitive | Only suitable for small ancillary uses |
From a performance perspective, the oxygen quality from an Oxygen generator is stable and well-suited to most oxy-fuel and oxygen-enrichment applications. Liquid oxygen provides higher purity, but the combustion and melting benefits relative to 93 percent oxygen are often marginal for most glass products. As a result, many plants choose an Oxygen generator to capture the majority of oxy-fuel benefits with lower long-term cost and greater independence.
Integrating an Oxygen generator into glass production lines involves designing the layout, piping, controls, and safety systems so that the generated oxygen reliably feeds furnaces, boosting systems, and auxiliary uses without disrupting existing operations.
The integration process usually starts with a site survey to identify available space, utilities, and access for installing the Oxygen generator. Containerized systems can be placed outdoors on a concrete pad, while skid-mounted Oxygen generator units may be installed inside a utility building. Considerations include ambient temperature range, noise, access for maintenance, and proximity to the main oxygen consumers to minimize piping lengths.
Next, engineers design the oxygen distribution network. This involves sizing pipes for the maximum expected flow, selecting materials compatible with oxygen service, and including appropriate filtration and isolation. For an oxy-fuel furnace, oxygen from the Oxygen generator may be split into several headers feeding different burner groups, each with its own control valve. Redundant lines may be added to maintain supply in case of maintenance or fault.
Control integration is equally important. The Oxygen generator should interface with the plant’s DCS or SCADA to allow real-time monitoring of oxygen purity, flow, and pressure, and to send alarms if these parameters fall outside specified limits. Furnace control logic may also be modified to adjust burner settings automatically when oxygen flow changes. For example, during planned downtime of one furnace, the Oxygen generator may reduce output or divert oxygen to another line without manual intervention.
Finally, commissioning involves performance testing under various load conditions, tuning control loops, and training operators and maintenance staff. Documented procedures for startup, shutdown, and emergency response ensure that the Oxygen generator can be safely managed by the plant team.
To maximize the benefits of an Oxygen generator in glass production, plants should follow best practices in operation, safety, and preventive maintenance, focusing on air quality, leak control, equipment inspections, and staff training.
Operationally, the Oxygen generator should be run within its design envelope for flow, purity, and pressure. Excessive turndown or overloading can reduce oxygen purity and shorten the life of molecular sieves. Regular checks of inlet air quality, including filtration and dryer performance, are essential because oil, water, or particulates can contaminate the adsorbent beds and degrade the Oxygen generator’s performance over time.
Safety is a critical aspect of any oxygen system. Even though an Oxygen generator produces oxygen at moderate pressure compared with high-pressure cylinders, oxygen-enriched environments greatly increase the risk of combustion. Best practice includes using oxygen-compatible materials, avoiding oil and grease on oxygen-contact parts, providing adequate ventilation around the Oxygen generator, and establishing strict no-smoking and no-open-flame zones. Safety valves, pressure relief devices, and emergency shutdown procedures must be installed and tested regularly.
Preventive maintenance programs are vital. Typical tasks include inspecting filters and replacing them on schedule, verifying dryer operation, checking for leaks in piping, calibrating sensors, confirming the accuracy of flow meters and purity analyzers, and periodically checking the condition of adsorption vessels. Many modern Oxygen generator packages offer remote monitoring, allowing technicians to detect trends, predict issues, and schedule maintenance before they cause unplanned outages.
From a personnel standpoint, training should cover both the technical aspects of operating an Oxygen generator and the safety culture around oxygen use. Operators should understand what purity and flow readings mean, how to interpret alarms, and what steps to take in abnormal situations. Maintenance staff should be trained in lockout/tagout procedures, oxygen cleaning standards, and the specific service requirements of the compressors, blowers, and adsorption beds that make up the Oxygen generator system.
For modern glass plants, adopting an on-site Oxygen generator is one of the most effective ways to enhance furnace efficiency, improve glass quality, cut fuel and logistics costs, and comply with increasingly strict environmental regulations.
High-purity oxygen supplied by an Oxygen generator allows glass furnaces to move from conventional air-fuel combustion toward oxy-fuel or oxygen-enriched firing, boosting flame temperature and heat transfer while cutting NOx emissions and fuel consumption. PSA and VPSA Oxygen generator technologies provide reliable, continuous oxygen at around 93 percent purity, which is more than adequate for most glass melting processes.
Compared with delivered liquid oxygen or cylinder supply, an industrial Oxygen generator offers superior long-term cost control and supply security, especially for continuous furnaces. By carefully specifying flow, purity, pressure, and energy performance, and by integrating the Oxygen generator into plant control systems and safety procedures, glass producers can align oxygen supply with their operational and sustainability goals.
As the glass industry continues to pursue higher productivity and lower emissions, the Oxygen generator is becoming a core utility asset rather than an optional add-on. Plants that invest in robust, well-designed Oxygen generator systems position themselves to respond quickly to market demand, meet tightening environmental standards, and deliver high-quality glass with confidence for years to come.
