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Show 0 0.2 1.0 1.4 [L/D) Axial Oistame from Burner Tile End Fig. 18 Comparison of temperature distribution in the furnace .Horizontal position 100 m m above the bottom of the furnace shows that a high flame emissivity of the low N O x burner is contributed by luminous flame radiation. Next, Model E and Model E E low N O x burners are compared with respect to axial temperature distribution in the horizontal position 100 m m above the bottom of the furnace in the case of heavy oil used as fuel Because the heated object is usually placed on the lower part of a burner, temperature distribution at this position is thought to indicate heating performance of a burner. These results are shown in Fig, 18. As stated previously, temperature distribution of a burner becomes important in examination of its heating property. Model E E has the fattest distribution of temperature 100 m m above the furnace bottom . With Model E, temperature directly below the burner is low, and after that it goes up. When compared with this average temperature, Model E and Model E E are almost the same, but the conventional burner is rather lower than that. In this way, our low N O x burners are not merely high in radiant heat flux but have the outstanding feature that they can be selected by adjusting the flame temperature distribution to the heated object. 2-5. Examples of application in actual furnace Since there are many operational factors, quantitative grasping of the energy saving effect by change of burner is quite difficult. However, one or two instances shall be mentioned below: 2-5-1. Example of application in continuous heating furnace. This low NOx burner (Model E) was used in butane burning continuous heating furnace of the upper and lower each three zones type. Prior to the improvement, this furnace was equipped with a low N O x burner available on the market, and concentration of N O x emitted therefrom was approximately 120 ppm. For a N O x counter-measure, Model E low N O x burner was installed. As for direction of fuel injection, the upper zone burner was faced downward; the lower zone burner, upward. This was done to compensate the drop in temperature of the flame due to adoption of Model E low N O x burner by bringing the flame close to the product. By this, N O x value became less than half that of the previous time to 40 ~ 50 ppm. Figc 19 shows the comparison of results of calculations of the overall heat absorptivity 4CQ upon measurement of slab temperature when the low N O x burner and the conventional burner are used. Temperature of the atmosphere above the slab surface rose by about 50 ~ 100°C, and its heating 11- 10 - |