Method for heating the reducing gas of a blast furnace by means of a plasma generator

Method for heating the reducing gas of a blast furnace by means of a plasma generator having a nozzle with an outlet orifice, comprising:

• injecting said reducing gas through an inlet pipe having a wall with an inner lining and a terminal tuyere of injection into said blast furnace, the axis of said terminal tuyere and the axis of at least a portion of said inlet pipe near said terminal tuyere being aligned;
• injecting the plasma jet generated by said plasma generator into said inlet pipe through said outlet orifice of said nozzle in the vicinity of said terminal tuyere so as to keep said plasma jet away from the wall of said inlet pipe thereby causing minimal or no damage to the inner lining of the inlet pipe;
• and
• the axis of said nozzle converging towards a point of intersection with said axis of said portion of said inlet pipe, and forming an acute angle A between the axis of the nozzle and the axis of said portion of said pipe being greater than zero and at most equal to 50.degree., the distance l separating said point of intersection from the center of said outlet orifice of the nozzle being at the most equal to
• D/2 sin A
• D being the inner diameter of the reducing gas inlet pipe, and the ratio
• D/d,
• in which d is the inner diameter of said outlet orifice of the nozzle, being at least equal to 1.5.