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Show A B S T R A C T Industrial glass producers are increasingly faced with the need to balance glass production and quality with environmental concerns. This paper summarizes the results of a study whose objective was the exploration of several N O x reduction strategies proposed for use in industrial float glass furnaces. The technologies included the introduction of an oxygen lance to simulate staged combustion, and oxygen/fuel firing. As a secondary investigation, the influence of soot on furnace operation was also explored. These strategies were compared by simulating numerically the turbulent reacting flow and heat transfer in the industrial environment of a full-scale float glass furnace. They were compared on the basis of four figures of merit: 1) fuel utilization efficiency, 2) combustion efficiency, 3) radiative heat flux uniformity on the glass melt surface, and 4) N O x evolution in the combustion gases. INTRODUCTION High energy consumption and potential for large pollutants generation characterize the high temperature environment in float glass melting furnaces. Improving energy efficiency and product quality while at the same time reducing pollution can have a tremendous impact on competitiveness of the glass industry. Generally speaking, measures taken to reduce the NO„ generation compete with steps proposed to increase energy efficiency. The purpose of this study was to explore several different N O x reduction techniques conceived for use in the environment of float glass furnaces using comprehensive numerical modeling of the turbulent combustion and heat transfer. A regenerative float glass furnace is shown schematically in Fig. 1. Multiple flame jets pass over the batch and melt to provide the energy for melting. In the case of regenerative furnaces the exhaust gases pass through a matrix of high temperature refractory brick which recoups exhausted energy. After a short period the flame jets reverse and the combustion air is drawn through the heated brick and the air is preheated. Figure 1. Schematic illustration of typical industrial float glass furnace. Recent developments in the advanced modeling methodology of the combustion processes in glass melting furnaces provide confidence in the numerical simulation of the complexities of turbulent mixing, chemical kinetics, soot generation, radiation heat transfer, etc. in these furnaces. A representative but not exhaustive list of prior work investigating combustion in glass melting furnaces in- |
