Development of NOx Control Methods for Glass Melting Furnaces

摘要

The purpose of this work is to provide experimental data that would help the glass industry significantly reduce NOx emissions from natural-gas-fired melters. Experiments were carried out on a relatively large (2 million Btu/h fuel input) pilot-scale furnace at IGT using scaled melter ports. The glass tank load was simulated by a heat sink consisting of a top layer of molten glass. The furnace temperatures and port operating parameters were maintained within limits of commercial container glass operations. Significant reductions in NOx emissions were achieved by (1) decreasing fuel/air mixing rates; (2) burning about half the fuel with all the combustion air, and injecting the remaining fuel to mix with the flame downstream of this highly fuel-lean combustion zone; and (3) operating the furnace at close to stoichiometric conditions and adding ambient air to furnace exhaust gases to complete combustion. The results show that it may be possible to reduce NOx production in commercial glass melters, without adversely affecting the heat-transfer to the melt, by properly controlling the fuel/air mixing. These results were obtained on a pilot-scale furnace under simulated glass melter conditions and should be demonstrated on full-scale commercial melters before definitive conclusions can be drawn about the effectiveness of these NOx control methods.