| OCR Text |
Show Accordingly, to eliminate the fire bridge is to reduce - the "furnace temperature" which affect NOx generation, and the effect can be evaluated not only for energy saving but for NOx reduction as well. From this viewpoint, the alteration of the indirect heating into direct heating of the drying furnace as described above can be evaluated highly as an effective mean for low NOx. It will be necessary to review the operating furnace temperature for both low NOx arrangement and for energy saving. With heating furnaces for forging, attention is centered only on the smooth processing of forging work and "Over forging" is seen rather often. 3 Air preheating One of the most important measures for energy saving, the exhaust heat collection by air preheating is not advantageous from the point of NOx reduction, and this is a rare case where energy saving and J-ow NOx rr>r\f\ ic-t- each other. The test result with straight flame burner indicates that . the NOx concentration is almost doubled at air temperature of 300°C, as shown in Fig.85. Moreover, the influence for air temperature over NOx is increased as the furnace temperature becomes higher, as shown in Fig.86. 8 - 80 - |
