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AssigneesVoest-Alpine Industrieanlagenbau GmbH, Pohang Iron & Steel Co., Ltd., Research Institute of Industrial Science & Technology, Incorporated Foundation
InventorsWerner Leopold Kepplinger, Felix Wallner, Johannes-Leopold Schenk
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In a process for producing molten pig iron or liquid steel pre-products, from particulate iron-oxide-containing material by fluidization, the iron-oxide-containing material is prereduced in at least one prereduction stage (7) by aid of a reducing gas and subsequently is reduced to sponge iron in a final reduction stage (8), the sponge iron is melted in a meltdown-gasifying zone (11) under the supply of carbon carriers and an oxygen-containing gas, and a CO- and H.sub.2 -containing reducing gas is produced which is introduced into the final reduction stage (8), is reacted there, is drawn off, subsequently is introduced into a prereduction stage (7), is reacted there, is drawn off, subjected to scrubbing and subsequently is carried off as an export gas and wherein at least a portion of the reacted reducing gas is purified from CO.sub.2, is heated and is used as a recycle-reducing gas for the reduction of the iron-oxide-containing material. To ensure reduction while avoiding the occurrence of "sticking", while also minimizing the amount of carbon carriers charged, a portion of the reducing gas flowing from the final reduction stage (8) into the prereduction stage (7) is branched off, washed, purified from CO.sub.2 and heated and subsequently is recycled to the final reduction stage (8) (FIG. 1).
A process for producing molten pig iron or liquid steel pre-products, from particulate iron-oxide-containing material by fluidization, wherein the iron-oxide-containing material is prereduced in at least one prereduction stage (7) by aid of a reducing gas and subsequently is reduced to sponge iron in a final reduction stage (8), the sponge iron is melted in a meltdown-gasifying zone (11) under the supply of carbon carriers and an oxygen-containing gas, and a CO- and H.sub.2 -containing reducing gas is produced which is introduced into the final reduction stage (8), is reacted there, is drawn off, subsequently is introduced into at least one prereduction stage (7), is reacted there, is drawn off, subjected to scrubbing and subsequently is carried off as an export gas and wherein at least a portion of the reacted reducing gas is purified from CO.sub.2, is heated and is used as a recycle-reducing gas for the reduction of the iron-oxide-containing material, characterized in that a portion of the reducing gas flowing from the final reduction stage (8) into the prereduction stage (7) is branched off, washed, purified from CO.sub.2 and heated and subsequently is recycled to the final reduction stage (8).
A plant for producing molten pig iron or liquid steel pre-products comprising at least two fluidized bed reactors (1, 2, 3) consecutively arranged in series, wherein the iron-oxide-containing material is conducted from fluidized bed reactor (1) to fluidized bed reactor (2, 3) via conveying ducts (6) in one direction and the reducing gas is conducted from fluidized bed reactor (3) to fluidized bed reactor (2, 1) via reducing-gas connection ducts (13) in the opposite direction, and comprising a melter gasifier (10) into which a conveying duct (9) conducting the reduction product from the fluidized bed reactor (3) arranged last in the flow direction of the iron-oxide-containing material runs and which includes feed ducts (17, 16) for oxygen-containing gases and carbon carriers as well as a tap (18) for pig iron or steel pre-material and slag as well as a reducing-gas feed duct (12) for reducing gas formed in the melter gasifier (10), which runs into the fluidized bed reactor (3) arranged last in the flow direction of the iron-oxide-containing material, characterized in that from the reducing-gas connection duct (13) connecting the fluidized bed reactor (3) arranged last in the flow direction of the iron-oxide-containing material with the preceding fluidized bed reactor (2), a branch duct (21) departs that runs into the reducing-gas feed duct (12) via a scrubber (22), a CO.sub.2 -elimination means (24) and a gas heater (25).
Dependencies are inferred from the claim text.