US 12,305,926 B2
Methods for preheating metal-containing pellets
Gregory J. Buragino, Macungie, PA (US); Anup Vasant Sane, Allentown, PA (US); Shailesh Pradeep Gangoli, Allentown, PA (US); Xiaoyi He, Orefield, PA (US); and Larry Saul Zelson, Macungie, PA (US)
Assigned to Air Products and Chemicals, Inc., Allentown, PA (US)
Filed by Air Products and Chemicals, Inc., Allentown, PA (US)
Filed on Aug. 9, 2021, as Appl. No. 17/397,021.
Application 17/397,021 is a division of application No. 16/025,230, filed on Jul. 2, 2018, abandoned.
Claims priority of provisional application 62/621,754, filed on Jan. 25, 2018.
Prior Publication US 2021/0364237 A1, Nov. 25, 2021
Int. Cl. F27D 13/00 (2006.01); C21B 13/00 (2006.01); C21C 5/52 (2006.01); C22B 1/02 (2006.01); F27B 3/08 (2006.01); F27D 3/00 (2006.01); F27D 3/08 (2006.01)
CPC F27D 13/00 (2013.01) [C21B 13/0086 (2013.01); C21C 5/527 (2013.01); C22B 1/02 (2013.01); F27B 3/085 (2013.01); F27D 3/0033 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A method for preheating metal pellets before charging into a melting furnace, wherein the pellets are transported by a conveyor belt to a chute and discharged from the chute into the melting furnace, the method comprising:
heating the pellets by direct flame impingement from two or more banks of burners, wherein the two or more banks of burners comprise an upstream bank of burners and a downstream bank of burners;
controlling the upstream bank of burners to operate oxygen-rich so as to create an oxidizing zone and the downstream bank of burners to operate fuel-rich so as to create a reducing zone;
measuring at least one process condition; and
controlling the two or more banks of burners based on the at least one process condition;
wherein when the at least one process condition is a concentration of one or more gases in the hot flue gas, adjusting the two or more banks of burners based on the concentration of one or more gases in the hot flue gas;
wherein when the at least one process condition is one or more temperatures selected from the list of the gas temperature, pellet temperature, or belt temperature, adjusting the two or more banks of burners based on the one or more temperatures; and
wherein when the at least one process condition is a safety condition, shutting down the two or more banks of burners in the event the safety condition is detected.