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In recent years, the glass industry has become an important consumer of gases. With tightening environmental laws, and improved productivity, oxygen has become a prominent feature in glass furnaces that make TV Glass, Sheet glass for buildings, vehicle windscreens, bottle, tableware for cooking, optical glass and many others. This happens by making fuel burn faster and more efficiently with less heat escaping from the furnace.
General Oxygen Enrichment - All fuel needs oxygen to burn. Air which has 21% oxygen, has been traditionally used. Huge air compressors blow air into furnaces - this air stream can be enriched from 21% to as high as 25% oxygen. This enriched oxygen stream causes the fuel, be it heavy oil, light oil, kerosene, petrol, LPG [liquefied petroleum gas] or natural gas to burn more efficiently.
Underflame Oxygen Enrichment - Similar to general oxygen enrichment described above, except that there is a pipe [called a lance] that blows oxygen directly under the flame. Productivity is higher than general enrichment.
Oxygen Boosting - In this scenario, the existing air-fuel burners continue firing in the same mode. In addition, one or more oxy-fuel burners are installed to burn the fuel directly with oxygen in the relatively colder parts of the furnace. The efficiencies are far higher than general or underflame enrichment.
100% Oxy-Fuel Firing Furnace - These new furnaces are revolutionary, smaller and far cheaper to construct since they do not have elaborate heat recovery mechanisms. Picture 79% of nitrogen and other gases that go into the ordinary furnace 'cold' and come out hot - this is a big waste of useful heat. 100% oxygen furnaces have little nitrogen [less than 10%] thus lose very little heat. This type of furnace gives the best efficiency and very high production capacities, far higher than traditional furnaces that have the same melting surface area.
All of these processes are based on the replacement of air with oxygen. The advantages of using oxygen:
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Reduced emissions
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Lower Capital costs
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Energy Saving
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Increased Productivity |
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Enhanced glass quality |
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Replacement of missing combustion air |
Nitrogen & Hydrogen - TV and float glass furnaces those that produce flat tinted sheets for buildings and vehicle windscreens have used a mixture of nitrogen and hydrogen in the melting process. This mixture is a 'scavenger gas' - since it eliminates the presence of oxygen in the furnace. Oxygen can cause the glass quality to severely deteriorate in some processes.
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