Rotary kiln and method of using such a kiln
AssigneeKawasaki Jukogyo Kabushiki Kaisha
InventorsTakuya Maeda, Tsutomu Yamada, Mitsuharu Kishimoto, Atsuyoshi Kubotani
Life of this patent
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Abstract
This disclosure relates to a rotary kiln for heating and calcining lime, waste, etc. and to a method of direct reduction of metal oxide using such a kiln. A cylindrical outer shell is mounted for rotation on its axis, and a stationary inner tube extends into the interior of the shell. Fuel and/or combustion air flow passages extend within the tube, and burner nozzles are supported by the tube and are connected to the passages. The tube is concentrically or eccentrically mounted adjacent the upper side of the space within the shell, thereby positioning the burner nozzles at the optimum positions.
Claims11
A rotary kiln for direct reduction using a solid reducing agent, said kiln comprising at least one substantially cylindrical shell rotatably mounted at an angle to the horizontal plane, at least one inner tube extending longitudinally into said shell and fixedly supported relative to said shell at both ends of said tube externally of said shell, said tube being covered over substantially its outer periphery by a refractory layer, said shell and tube forming a space therebetween, at least one flow passage for oxygen-containing gas provided within said tube, at least one nozzle tube supported by said inner tube, said nozzle tube extending radially through the wall of said inner tube and said refractory layer and connected with said passage, a burner nozzle located in said space, said nozzle being connected with said nozzle tube, and a temperature detector provided on the outside of said inner tube in said space.
A method of direct reduction using a rotary kiln and a solid reducing agent, said kiln including at least one substantially cylindrical shell rotatably mounted at an angle to the horizontal plane, at least one inner tube extending longitudinally into said shell and fixedly supported relative to said shell at both ends of said tube externally of said shell, said tube being covered over substantially its outer periphery by a refractory layer, said shell and tube forming a space therebetween, at least one flow passage provided within said tube, at least one nozzle tube supported by said inner tube, said nozzle tube extending radially through the wall of said inner tube and said refractory layer and connected with said passage, a burner nozzle located in said space and connected with said nozzle tube, and a temperature detector provided on the outside of said inner tube in said space;
- said method comprising the steps of charging said space with material that includes primarily metal oxide and carbon-containing material, injecting oxygen-containing gas into said space from said nozzle, heating the material by combustion heat from said nozzle and heat reflected by said refractory layer, detecting the temperature within said space by said detector, and controlling the amount of the injected gas to maintain proper temperature distribution within said shell.
Dependencies are inferred from the claim text.