Side-Fired Box and Car-Bottom Furnaces

Side-fired box and car-bottom furnaces are ideally fired with main burners on 2.5-ft to 4.5-ft (0.6 m to 1.4 m) centers along the top on one side, and small pumping high-velocity burners on the opposite bottom side. (See fig. 6.1.) The main burners should have ATP technology so that the temperature can be controlled to a flat profile with the T-sensors located at the level of the top of the load through each of the two long sidewalls. 

The loads should be on piers so that small, high-velocity burners can be fired underneath. For practically constant temperature under the loads, the base pier height should be 5 to 9 (0.13 to 0.23 m) and the burners fired with constant air. Uniform temperature will result from the fact that the thin gas blanket will transfer only about one-third as much heat as above the load, so the blanket temperature will fall very slowly as it moves under the load. Therefore, load temperature profile across the furnace and below the load as well as above will be practically flat, leading to less than 10°F ( 5°C) temperature differential throughout the load. 

When conventional burners are used to side fire a furnace, they produce larger differentials across the furnace. These larger temperature differences stem from the changeable thermal profile of the burner at different firing rates. At high-firing rates. 

SAFETY SHOULD BE THE UTMOST PRIORITY of all furnace engineers. . . above quality, before productivity, preceding pollution control, outpriori-tizing labor minimization, and overshadowing fuel economy  

Thorough study of section 6.6.2, plus Combustion Supervising Controls in pt 7 of reference 52, is imperative for your own personal safety, for your job, and for the whole organization in which you work. 

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