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REMOVING FOAM FROM MELT SURFACE OF OXYGEN-FUEL FIRED GLASS MELTING FURNACES

IP.com Disclosure Number: IPCOM000199521D
Publication Date: 2010-Sep-07
Document File: 7 page(s) / 308K

Publishing Venue

The IP.com Prior Art Database

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Title:   Removing foam from melt surface of oxygen-fuel fired glass melting furnaces

Summary of the Invention:

The invention is to remove the foam from the melt surface of glass-melting furnaces mechanically, which is able to overcome the problem caused by the foam layer in the oxy-fuel fired glass-melting furnaces. Water-cooled steel pipes and overflow outlets are combinative used for the foam remove. A high temperature-resistant steel pipe cooled by water stretches into the furnace combustion space from side wall. The steel pipe could be located at any location in front of the batch coverage. The steel pipes are crossed the entire furnace width or the most part of furnace width and just few millimeter above the glass melt surface. The steel pipes stretched into the furnace from side walls could be straight, also could be angled. An overflow outlet is built at each side wall, which is located at the same location as the steel pipe opening. The straight or angled steel piping stops the foam layer moving forward and forces it flowing out the furnace from both overflow outlets. Heat transfer from combustion space to glass surface, furnace thermal efficiency and glass melt quality will be improved significantly. When the entire foam layer or the most part of the foam layer is removed, the furnace crown temperature will reduce 50K to 100 K. Therefore, a large amount of energy saving will be obtained and the furnace life will be increased also. The thermal efficiency oxygen-fuel combustion system will be used by more glass companies worldwide.

BACKGROUND OF THE INVENTION

1.      Field of the Invention

The present invention relates to a method of removing foam from melt surface of oxy-fuel fired glass-melting furnace, which improves heat transfer from combustion space to glass surface, furnace thermal efficiency, and glass melt quality.

2.      Description of the Prior Art

In recent years, many glass-melting furnaces have been switched to oxy-fuel firing system from traditional air-fuel firing system. The oxy-fuel firing enhances combustion, reduces NOx, CO2 and also reduces total energy input which is very help for furnace energy saving and furnace pollutant emission reduction.

In the process of batch melting and glass refining in glass-melting furnaces, gases are released from raw materials and molten glass, producing large amount of bubbles. These bubbles agglomerate and form a foam layer on the batch and glass surfaces. In traditional air-fuel fired glass-melting furnaces, foam zone is located at the end of batch blanket area which covers part of melting surface. On top surface of glass tank, first is the batch coverage zone, then foam area, then free glass surface. When the oxy-fuel firing system is used in the glass-melting furnaces, high partial pressure of water vapor in the combustion space greatly increases the foam generation. A thick foam layer on glass melt surface is created in the oxy-fuel fired glass-melting furnaces [1, 2]. Such as in fibe...