Double-hearth arc furnace for preheating scrap material and method of operating the same

A double furnace arrangement, comprising:

• --first and second tiltable furnace vessels, each of said vessels having an interior run-off tap region and an interior slag door region defining a first and second interior bay regions respectively at opposite sidewalls thereof;
• --a connection line in fluid communication with said interior run-off tap and slag door region of each of said first and second tiltable furnace vessels respectively;
• --first and second conduits for interconnecting the furnace vessels, said first conduit including a combustion chamber having first and second flanged pipe sections connected thereto with first and second shut off valve means provided in said first and second pipe sections, respectively, and said second conduit having a flange at each end and including third and fourth shut-off valve means;
• and
• --means for releasably coupling said connection lines to flanges of said conduits for permitting tilting of each furnace.

A double furnace arrangement, comprising:

• --first and second tiltable furnace vessels, each of said vessels having a run-off tap and a slag door and each defining, on opposite sides thereof, first and second interior bay regions disposed over said tap and proximate said slag door, respectively;
• --connection lines in fluid communication with said bay regions;
• --first and second conduits for interconnecting the furnace vessels, said first conduit including a combustion chamber having first and second flanged pipe sections connected thereto with first and second shut off valve means provided in said first and second pipe sections, respectively, and said second conduit having a flange at each end and including third and fourth shut-off valve means;
• and
• --means for releasably coupling said connection lines to flanges of said conduits for permitting tilting of each furnace.

A process for operating a double furnace installation having two arc furnaces connected via a line, a power supply, a device for charging material, and an arrangement for extraction and a purification of gas, said each arc furnace has a run-off tap and a slag door and each defining, on opposite sides thereof, first and second interior bay regions disposed over said tap and proximate said slag door respectively and diametrically opposite to one another comprising the steps of:

• connecting a first one of the furnaces with the power supply for melting a charge located therein;
• isolating a second one of the furnaces from the power supply;
• charging the second furnace with charging material;
• closing the second furnace with a cover;
• sucking flue gas generated during a melting phase out of the first furnace;
• introducing the flue gas into the second furnace through a first interior bay region of the second furnace;
• passing the introduced flue gas along a substantially horizontal path through the charging material in the second furnace;
• and sucking the flue gas from the second furnace through a second interior bay region.