PERFORMANCE-INCREASING, NITROGEN OXIDE-REDUCING CROSS-FIRING OF TANK FURNACES

摘要

The disclosed cross-flame arrangement of cross-fired tank furnaces aims at a relative reduction of flame and roof temperatures in order to improve furnace performance and reduce nitrogen oxide. By partially deflecting fuel jets sideways out of the combustion air flow with several burners and orifice jewels, the starting reaction of the flame is subdued, a "cold" flame root is set, and NO is reduced. At the same time, a carburating effect is achieved, increasing the emission coefficient of the flame. Next to the furnace walls, therefore, it acts at first as a heat sink, but in the centre of the furnace, the heat emitted by the flame is intensified instead of its temperature (reducing its maximum values and NO emissions). The deflection of the flames into a fan flame pattern also increases flame length and the extent of coverage of the melt surface by the flames, lengthens the path of the flames and shortens the path of thermal radiation to flame-distant areas of the glass bath surface. Flame position may be vertically adjusted to give a uniform distance from the molten glass. The temperature in the upper part of the furnace is relatively reduced, lowering NO emission and increasing melting capacity. The improved heat radiation lowers the temperature at the outer end of the flame. In addition, the temperature reduction next to both furnace walls increases glass transverse flow in the lower part of the furnace, improving its performance.