Method of production of secondary steel based on scrap
AssigneeSMS Siemag Aktiengessellschaft
InventorMatthias Meyn
Life of this patent
Estimating the term…
Abstract
With the production of the secondary steel based on scrap, wherein the scrap (10) is fed in a scrap preheater (2) through a charging device (1), is preheated there and, finally, is brought into a smelting unit (3) and is melted there with primary energy only, the process gases (19), which leave the smelting unit (3), are not used for directly preheating the scrap (10) but are rather used indirectly by heating a gaseous preheatable medium, e.g., air (18) or inert gas, so that energetic, fluidic, and spatial decoupling of preheating and melting and of post-combustion and preheating is achieved.
Claims1
A method of producing secondary steel based on scrap (10), comprising the steps of feeding the scrap (10) into a scrap preheater (2) and heating the scrap (10) in the scrap preheater (2);
- feeding the heated scrap from the scrap preheater (2) into a smelting unit (3);
- melting the scrap in the smelting unit (3);
- feeding process gas (19), which is produced in the smelting unit (3), from the smelting unit (3) into reheating device (4);
- in the reheating device (4), freeing the process gas (19) of harmful materials;
- cooling a clean process gas (19) that leaves the reheating device;
- feeding the cooled process gas in a dedusting installation (8) located downstream of the reheating device (4) and freeing the process gas there of dust;
- discharging the cooled cleaned process gas as a cooled cleaned flue gas (19′), wherein the step of feeding the process gas from the smelting unit into the reheating device includes feeding the process gas directly into the reheating device (4), and the cooling step includes cooling the reheated process gas in a heat exchanger (5, 6) by heating another gas (18, 21) that flows through the heat exchanger, wherein the step of preheating the scrap in the scrap preheater (2) is carried out by hot another gas that was heated in the heat exchanger (5), the another gas being one of air (18), air enriched with oxygen, and inert gas (21), wherein the another gas is inert gas (21), the method comprising the step of heating air (18) necessary for post-combustion in a heat exchanger (16) located downstream of the heat exchanger (5) in which the inert gas (21) is heated.
Dependencies are inferred from the claim text.