Glass Melting Technology: A Technical and Economic ... - OSTI

and PPG Inc. in the United States address the problem encountered by continuous tank furnaces
of recirculation flows into the melting tank that limit or, which limit the maximum residence
time of molten glass in the tank. The key components of the segmented system that offer the
greatest promise are batch preheating, driven dissolution in the fusion process, and innovative
refining. The PPG P-10 process is one of the most revolutionary advances in glass melting of the
20th century. This system optimizes each phase of the glass fusion process, combining
techniques for melting, refining and homogenizing soda-lime glass. In addition, it was designed
to be nonpolluting and minimize residence times. The British Glass industry designed the Glass
Plasma Melter to demonstrate energy savings in manufacturing soda-lime silica glass.
Accelerated melting systems have been designed to agitate the batch so that it never remains
undisturbed on the surface of molten glass. Innovative approaches have been taken to develop
melters that have a melting rate proportional to a volume rather than to a surface area and will
allow production demands to be met by smaller furnaces. Among these innovative technologies
are Submerged Combustion Melting (Glass Container Industry); GI-GTI Submerged Melter;
Advanced Glass Melter (Gas Research Institute); and systems for nuclear waste vitrification.
To address the shortcomings of electric furnaces, i.e., glass quality is insufficient and furnace
refractory corrosion, a number of innovative technologies has been patented. Among these
technical innovations are suspended electrodes and refining zones for electric melters.
Batch preheating has been an area of considerable study because much heat from the energyintensive
process of glassmaking is lost through exhaust gases that could be used to preheat
batch and cullet. Energy costs and emissions can be reduced through this technology. The E-
Batch system developed by BOC Gases in 2001 is the most recent technology that has been
developed. It is unique in that it has been designed to be integrated with oxy-fuel-fired furnaces,
and it incorporates exhaust gas cleaning to a stringent regulatory level. The Nienburger Glas
Batch Preheater has been one of the most successful preheating technologies explored. Furnace
exhaust gases and a batch and cullet mixture are in direct contact inside a hopper, and furnace
energy savings of up to 29 percent have been reported in five installations in Germany.
Non-conventional methods that combine melting and refining include the Rapid Melting and
Refining (RAMAR) system developed by Owens Illinois, which has never been used in
production but bears features worthy of consideration for future melters. Saint-Gobain has
developed the FAR system, which combines flame fusion and electrical refining and the FARE
system, which replaces the FAR flame melter with a single-stirred electric melter.
Environmental regulations to restrict emissions from fossil fuel furnaces have encouraged
consideration of all-electric melters, which eliminate most air emissions concerns but are not
economically feasible. Two innovations for emissions control are considered: Körting Gradual
Air Lamination and the Sorg LoNox furnace.
The variety and extent of innovations in glass melting technology that have been researched and
developed—or abandoned—over the last quarter of the 20th century depict the exhaustive search
for revolutionizing the glass melting process to meet the long-range needs of glass manufacturers
into the 21st century. The technologies reviewed here suggest the vast potential for a
revolutionary glass melting system.
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