Process and plant for preheating a metal charge fed in continuous to an electric melting furnace

A plant for implementing a process for preheating a metal charge fed in continuous to an electric melting furnace through a preheating tunnel provided with side walls, a vault and a horizontal conveyor, wherein said metal charge is enveloped in countercurrent by fumes or exhaust gases exiting from said electric melting furnace and by jets of gas ejected by a plurality of nozzles arranged on the vault of said preheating tunnel, said plant comprising:

• suction fans, and openings other than the plurality of nozzles, arranged along the preheating tunnel, said fans and/or said openings being adjustable for sucking air from a surrounding environment to obtain a condition of complete combustion of said fumes or exhaust gases, said condition being verified based on measurements by temperature sensors and/or on composition of outgoing gases at a terminal part of said preheating tunnel or downstream of said terminal part,
• wherein at least two groups of said nozzles are provided on the vault of said preheating tunnel, spaced apart in a longitudinal direction with respect to the preheating tunnel, and
• wherein said nozzles are non-uniformly distributed longitudinally along said preheating tunnel.