Method and system for removing carbon deposit at electric heating system in a direct reduction plant utilizing hydrogen

A direct reduction system comprising:

• an electric heater system adapted to heat a reduction gas;
• a shaft furnace adapted to receive and utilize the heated reduction gas to reduce iron oxide and one or more of a carbonaceous gas and/or a carbonaceous material to carburize the reduced iron oxide to produce the direct reduced iron containing carbon;
• first and second valves for providing the reduction gas to an electric heating element of a first block of the electric heater system and an electric heating element of a second block of the electric heater system to heat the reduction gas using the electric heating element of the first block of the electric heater system and the electric heating element of the second block of the electric heater system;
• the first valve for stopping the providing the reduction gas to the electric heating element of the first block of the electric heater system;
• and
• a third valve for providing a hydrogen gas or a hydrogen gas with added steam to the electric heating element of the first block of the electric heater system to remove carbon deposition from the electric heating element of the first block of the electric heater system while continuing to heat the reduction gas using the electric heating element of the second block of the electric heater system such that the production of the direct reduced iron containing carbon with the shaft furnace is not interrupted.

A method for operating a direct reduction system comprising an electric heater system adapted to heat a hydrogen rich reduction gas comprising top gas recycled from a shaft furnace and the shaft furnace adapted to receive and utilize the heated hydrogen rich reducing gas to reduce iron oxide to produce the direct reduced iron, the method comprising:

• providing the hydrogen rich reducing gas to at least one electric heating element of the electric heater system to heat the hydrogen rich reducing gas;
• introducing one or more of a carbonaceous gas and/or a carbonaceous material to an interior of the shaft furnace to carburize the reduced iron oxide;
• using the heated hydrogen rich reducing gas in the presence of the one or more of the carbonaceous gas and/or the carbonaceous material to produce the direct reduced iron containing carbon;
• stopping the introducing the one or more of the carbonaceous gas and the carbonaceous material to the interior of the shaft furnace;
• reducing the iron oxide using only the heated hydrogen rich reducing gas to produce the direct reduced iron not containing carbon to remove carbon deposition from the at least one electric heating element of the electric heater system;
• and
• again introducing one or more of the carbonaceous gas and/or the carbonaceous material to the interior of the shaft furnace and again reducing the iron oxide using the heated hydrogen rich reducing gas in the presence of the one or more of the carbonaceous gas and/or the carbonaceous material to produce the direct reduced iron containing carbon.