Multi-burner rotary furnace melting system and method

A method of melting a charge in a double-pass tilt rotary furnace, the furnace having a chamber bounded by a generally cylindrical wall with an axis extending from a closed end to an open end, and a door configured to cover the open end, the method comprising:

• adding a charge containing solids into the chamber;
• rotating the furnace in a direction of rotation about the axis;
• operating a first burner at a first firing rate, the first burner being mounted in a lower portion of the door and producing a first flame having a length;
• operating a second burner at a second firing rate, the second burner being mounted in an upper portion of the door above the lower portion of the door and producing a second flame having a length, the second flame being distal from the charge relative to the first flame;
• exhausting combustion gases resulting from the first flame and the second flame through a flue positioned in the door above the charge;
• in an initial phase when the solids in the charge impede development of the first flame, controlling the second firing rate to be greater than the first firing rate;
• and
• in a later phase after melting of the solids in the charge sufficiently that development of the first flame is not impeded, controlling the first firing rate to be greater than the second firing rate;
• wherein as a result of the direction of rotation a submerging interface is formed wherein the cylindrical wall rotates into the charge and an emerging interface is formed wherein the cylindrical wall rotates out from the charge;
• and wherein the first burner and the second burner are positioned closer to the submerging interface than the emerging interface, and wherein the flue is positioned closer to the emerging interface than the submerging interface.