Glass Melting

By using oxygen and other industrial gases, BOC is able to tap the uncovered potential of your glass melting furnace, increasing production, improving quality, saving fuel and reducing emissions. Working with a variety of other combustion-led industries also allows us to harness the best practices of those industries for the benefit of the glass industry.

BOC’s glass melting technologies are based on the replacement of air in a furnace with oxygen. Replacing air with oxygen reduces the nitrogen concentration in a furnace, increasing available energy from fuel sources and efficiency. Elimination of Nitrogen leads to reduction in Nitrogen Oxides (NOx) and particulate emissions from glass furnaces.

Higher oxygen concentrations also result in higher concentration of CO2 and H2O, which are responsible for increased thermal radiation, resulting in better heat transfer. Other key advantages of using oxygen may be:

  • Lower capital costs
  • Fuel & Energy savings
  • Increased productivity
  • Enhanced glass quality
There are a number of oxygen-based glass melting technologies that BOC supports and they are selected based on the type and condition of your glass melting furnace. These technologies involve either one or a combination of the following processes:
  • Oxygen enrichment
  • Oxygen lancing
  • Oxy-fuel boosting
  • Oxy-fuel conversion

BOC’s Glass Melting technologies are:

Convective Glass Melting (CGM)

BOC’s patented Convective Glass Melting (CGM) technology increases the rate of heat transfer to the batch and thus increases the rate of melting. This benefit removes many of these limitations of conventional zero port boost and can provide increased performance improvements to many glass melters. The CGM burner is crown mounted and fires down onto the batch. The vertical orientation promotes an increase in convection currents in the bath, potentially offering a reduction in E-boost.

Typical Customer Profile 

Glass manufacturers requiring additional glass production due to:

  • Increased orders

  • Furnace design restrictions  

  • Overdependence on E-boost  

  • Failing regenerators or recuperators

Key Customer Benefits

  • Increased melt rates allow for increased production rates and/or better quality    

  • Crown burners allow for greater oxy-fuel boosting compared to conventional oxy-fuel with no additional side or end port space consumption    

  • CGM is ideal for No-Boron Fibreglass melting, with customers significantly reducing raw material costs    

  • Can be retrofitted to air fuel furnaces of most glass types (float, fiberglass, container, tableware, etc.)    

  • Extension of Furnace life

  • Burners can be run on a wide range of fuel sources

COROX® Hotspot Boost

BOC offers a flexible solution to increase the throughput or maintain the capacity of a glass furnace without significant capital investments.

The COROX® Hotspot Boost is a horizontal oxy-fuel burner system for end-port furnaces to increase the temperature of the oxy-fuel flame and improve the amount of energy radiated to the glass bath. This results in an increase in capacity of up to 10% for healthy furnaces. The technology also supports maintaining capacity for ailing furnaces and extending furnace life.

Typical Customer Profile   

Glass customers operating end-port furnaces in need of additional glass capacity due to initial design restrictions and failing regenerators.

Key Customer Benefits 

  • Production capacity increases of 10% on average for healthy furnaces  

  • Retain lost capacity (likely >10%) for ailing furnaces  

  • Prolong furnace life-time  

  • Better glass quality (higher packing rates)  

  • Potential fuel savings

COROX® LowNOx

COROX® LowNOx is a unique patent-pending fuel dilution and gas conditioning technology suited to both regenerative and recuperative endport glass furnaces. It employs special horizontal oxygen lances, which can be combined with oxy-fuel burners, to create atmospheric conditions that result in substantially reduced NOx emissions. It can be fitted to new furnaces or easily added to existing facilities with minimal space requirements.

COROX LowNOx works by injecting additional oxygen into the furnace through high-pressure lances. This creates a more intense, directional flue gas recirculation effect within the furnace. As a result, the main air/gas burner system produces a diluted, staged combustion process.
Fuel dilution leads to a more homogenous flame and a reduced flame temperature. As the flame temperature has a direct impact on NOx levels, this lowers emissions significantly. A lower flame temperature also reduces the concentration of hydrocarbon radicals in the furnace, thereby limiting NOx formation. In addition, an improved heat transfer rate shortens the window during which NOx can form.

NOx emissions can be further reduced and melting capacity increased by the addition of oxygen lances.

Key Customer Benefits

  • NOx emissions reduction of up to 65%   

  • Energy consumption reduced by between 3 and 5%  

  • Consistently high glass quality (e.g. no shift in T-profile, stable CO concentration)  

  • Furnace capacity increase of up to 15%  

  • Low up-front investment and operating costs

OPTIFIRE® Wide Flame Burner

Linde’s OPTIFIRE® wide flame burner has been successfully implemented in glass melting furnaces. It features a staged combustion process that provides high flame luminosity and low momentum, allowing optimum heat transfer during the melting process and preventing hot spots.

The burner generates a wide flame pattern that covers up to 200% more glass surface than conventional oxy-fuel burners. A variety of flame shape configurations can be promoted, including a “half-flame” for use near endwalls or for other process reasons. This flexibility allows the burner to be incorporated in any location in any type of furnace.

Key Customer Benefits 

Economic, environmental and production benefits can include:

  • Low momentum flames that reduce particulate emissions and crown corrosion  

  • Up to 50% NOx reduction compared to conventional oxy-fuel burners   

  • Wide flame pattern resulting in fewer burners per unit area of melter   

  • No burner cooling required   

  • “Quick-release” feature for easy installation and removal of burner metallic components  

  • Effective at foam mitigation

OPTIFIRE® JL Burner

The OPTIFIRE® JL burner is ideal for large area coverage. This burner is based on our innovative Dilute Oxygen Combustion technology and offers reduced glass furnace emissions. With proper placement, the burner minimises alkali volatilisation and particulate formation from the glass melt, which significantly reduces furnace refractory corrosion and promotes longer furnace life.

OPTIFIRE® XD Burner

The OPTIFIRE® XD burner is an extreme duty burner designed to offer a continuous, low-momentum flame. This burner's performance has proven successful in mitigating condensate build-up around the cooler oxygen ports and offers a quick-release feature for easy installation and removal of internal burner components.


BOC’s Waste Heat Recovery technologies are:

OPTIMELT® Thermochemical Regenerator System

The OPTIMELT® Thermochemical Regenerator System stores waste energy from the hot flue gas in regenerator checkers and subsequently utilises this heat to preheat fuel. This process provides the energy needed to endothermically reform the mixture of fuel mixed with carbon dioxide and water in the recycled flue gas. The result is the conversion of fuel to hot syngas resulting in fuel savings of up to 30% (compared to oxy-fuel and air regenerative glass furnaces).

What’s more, the OPTIMELT® Thermochemical Regenerator system delivers these results by using only 33% of the checker volume typically required for conventional regenerator systems. The complete system includes regenerators, flue gas recirculation equipment, ducting to the regenerators, blowers, oxygen injectors, and a proprietary control system.

OPTIMELT® Batch and Cullet Preheating Systems

Our OPTIMELT® batch and cullet preheating systems are ideal for gas-oxygen fired glass furnaces. These systems utilise the energy in the hot flue gas to preheat the cullet and/or batch. The systems allow for a direct contact heat transfer from glass furnace exhaust gases to the material being processed before being fed into the furnace. Depending on the cullet rate, the cullet preheating technology has been demonstrated to reduce fuel consumption by as much as 15%, in comparison to traditional oxy-fuel furnaces. When combined with batch preheating, fuel savings could increase to as much as 30% versus air regenerative furnaces and 20% versus oxy-fuel furnaces.

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