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Show REGENERATIVE BURNERS FOR RADIANT TUBESFIELD TEST EXPERIENCE Ted Davies North American Mfg. Co. Cleveland, Ohio, USA ABSTRACT Compact regenerative burners have been developed for both radiant-tube and direct-heating industrial process furnaces. This paper deals with field tests of the radiant tube burner on a continuous galvanizing furnace. Fig. 1 - Coil of Galvanized Steel I - THE PROBLEM THE STEEL in this picture was heated in a continuous galvanizing furnace at a midwest steel plant. The furnace is heated with 208 burners firing into 17.8 cm (7") O.D. "u" tubes. Furnace temperature is 982°C (1800F). Flue temperature is approximately l149°C (2l00F) . Burner capacity ranges from 131,850 W to 175,800 W (450,000 btu/h to 600,000 btu/h.) 65 Burners use cold combustion air at 527 Pa (12 osi) pressure. Fig. 2 - Continuous Strip Galvanizing Furnace The steel company wanted to improve the furnace operation in four (4) areas. First - Reduce the fuel cost without reducing production. Fuel was costing about two million dollars a year for the furnace. Second - Reduce scrap. The radiant tubes operated with a positive pressure. When a tube failed, the flue gas from the burner leaked into the furnace and contaminated the hydrogen-nitrogen protective atmosphere. This sometimes caused scrap. Therefore it was desirable to change the tube pressure from positive to negative. Third - Reduce the radiant tube replacement cost. To get maximum production, the tubes were transferring an average 36,312 W/m2 (80 btu/h/in2) of tube surface. This high rate caused the first leg of the tube to fail prematurely. Some tubes failed after three (3) months. |