Continuous Reheat Furnace Control

If the management cannot be convinced to fire under the loads, a minimum of 4 in. (0.10 m) vertical clearance between the loads and the hearth will provide considerably better temperature uniformity and productivity. However, the clearance must be maintained open by frequent removal of accumulated scale. 

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Q9. Where should control T-sensors be located for shortest heat cycles with protection for the product in a continuous reheat furnace ... 

Hg. 5.10. Continuous steel pusher reheat furnace side fired with regenerative burners in the top and bottom heat and preheat zones, and root tired in the soak zone. Preheat zones often have been designed as unfired preheat zones, which are good for fuel economy. However, also firing the preheat zones with regenerative burners would add capacity while retaining high fuel efficiency. (For a discussion of controls for this furnace, see sec. 6.11.1.)... 

Fig. 5.27. Continuous steel reheat furnace with nine pairs of regenerative burners in three top control zones and four pairs in a bottom zone. The sweep of hot poc from side burners can alternately proceed all the way across the furnace width, avoiding the former uneven heating when opposed burners created a hot spot pileup of heat in the center when on high fire, and a cool stripe down the middle on low fire.

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