Continuous scrap preheating
AssigneeConsteel, S.A.
InventorJohn A. Vallomy
Life of this patent
Estimating the term…
Abstract
A method and apparatus for reducing the production or emission of noxious gases while continuously preheating a mixture of iron-bearing scrap charge materials for an electric steelmaking furnace operation with off-gas from, the furnace, including provision for controlled combustion within the preheating chamber. Removed gases are then treated by thermal incineration of combustible residual matter before release into the atmosphere to insure that no noxious gases are emitted.
Claims29
A method for the continuous preheating of charge materials for a steelmaking furnace, comprising;
- a) continuously passing a preselected feed mixture of iron-bearing material and other feed materials through an elongated heating chamber having sequentially a feed mixture entry end, a gas transition section, a heating section and a feed mixture discharge section having a discharge end;
- b) establishing a dynamic seal at the feed mixture entry end of the heating chamber;
- c) heating the chamber and the feed mixture therein by passing hot gases through and over the feed mixture within the chamber, and combusting said gases to form combusted gases and associated off-gases, and to preheat the feed mixture;
- d) maintaining a change of oxygen concentration in the combusted and associated off-gases within the heating chamber from reducing at the mixture discharge end to slightly oxidizing to said feed mixture in the gas transition section;
- e) removing the combusted gases and associated off-gases from the gas transition section of the chamber;
- f) maintaining the temperature of said combusted and associated off-gases remove from said gas transitions at a temperature in the range of 900.degree. to 1100.degree. C. for a period of at least 2 seconds;
- and
- g) discharging the feed mixture continuously and directly into a steelmaking furnace.
Apparatus for the continuous preheating of charge materials for an associated steelmaking furnace, comprising:
- a) conveyor means, having a charge material entry end and a material discharge end;
- b) support means for said conveyor means;
- c) a cover over a portion of said conveyor means, forming a heating chamber with said support .means, said heating chamber comprising sequentially a gas transition zone, a heating zone, and a feed mixture discharge zone;
- d) gas seal means at the material entry end of said conveyor means to the heating chamber;
- e) means for connecting and sealing the heating chamber to a steelmaking furnace;
- f) means for introducing heat to the interior of said heating chamber;
- g) means for removing off gases at the material entry end of said heating chamber;
- and
- h) means for heating removed off gases to a high temperature in the range of 900.degree. to 1100.degree. C. and for holding said temperature for a period of at least 2 seconds.
Dependencies are inferred from the claim text.