SE2450937A1

SE2450937A1 - A method of and an arrangement for direct reduction of iron ore into sponge iron

Info

Publication number: SE2450937A1
Application number: SE2450937A
Authority: SE
Inventors: Farzad Mohseni-Mörner; Javad Fayazi
Original assignee: Hybrit Development Ab
Priority date: 2024-09-20
Filing date: 2024-09-20
Publication date: 2025-06-10
Also published as: SE547242C2

Abstract

An arrangement for producing sponge iron by direct reduction of iron ore, comprising a direct reduction shaft (1) with a reducing gas inlet (4) and a reducing gas outlet (5), a heat exchanger (10) provided for heat exchange between used reducing gas in a first gas line (8) and cleaned reducing gas in a second gas line (9), a cooling zone or cooling chamber (11) provided downstream the reduction zone (6) having a cooling gas inlet (12) and a cooling gas outlet (13). The arrangement comprises a third gas line (14) for conducting used cooling gas from the cooling gas outlet (13) to the first gas line (8) and mixing the used cooling gas with the used reducing gas at a mixing point (15) in the first gas line (8), the mixing point (15) being located upstream the heat exchanger (10) as seen in the flow direction of the reducing gas in the first gas line (8).

Claims

1. A method of producing sponge iron by direct reduction of iron ore, comprising the steps of: -introducing iron ore into a direct reduction shaft (1 ), -feeding the iron ore through the direct reduction shaft (1 ), -introducing a reducing gas comprising hydrogen gas into the direct reduction shaft (1) through a reducing gas in|et (4) and permitting the reducing gas to flow through the direct reduction shaft (1) in a direction opposite to the feeding direction of the iron ore in a reduction zone (6) of the direct reduction shaft (1), -removing used reducing gas from the reduction shaft (1) through a reducing gas out|et (5), -cleaning the used reducing gas removed from the reduction shaft (1) and conducting a part thereof comprising hydrogen gas to the reducing gas in|et (4), -exchanging heat, in a heat exchanger (10), between the used reducing gas before cleaning thereof and used reducing gas that has been subjected to said cleaning, -subjecting the sponge iron in a coo|ing zone or coo|ing chamber (11) downstream the reduction zone (6) of the direct reduction shaft (1) to a coo|ing gas comprising hydrogen gas and having a lower temperature than the sponge iron exiting the reduction zone (6), -removing used coo|ing gas from the coo|ing zone or coo|ing chamber (11) and from the reduction shaft (1 ), said method being characterised in that it comprises the steps of -mixing used coo|ing gas removed from the coo|ing zone or coo|ing chamber (11) and from the reduction shaft (1 ) with used reducing gas removed from the reduction shaft (1) through the reducing gas out|et (5) at a mixing point (15) located upstream said heat exchanger (10) as seen in a flow direction of the used reducing gas.

2. A method according to claim 1, wherein the coo|ing gas comprises at least 80 mole% hydrogen gas.

3. A method according to claim 1, wherein the coo|ing gas comprises at least 90 mole% hydrogen gas.

4. A method according to any one of claims 1-3, wherein at least 80 mole% of the reduction gas is comprised by used reducing gas removed from the reduction shaft (1) and used cooling gas removed from the cooling zone or cooling chamber (11).

5. A method according to any one of claims 1-4, wherein substantially all the reduction gas is comprised by used reducing gas removed from the reduction shaft (1) and used cooling gas removed from the cooling zone or cooling chamber (11).

6. An arrangement for producing sponge iron by direct reduction of iron ore, comprising: -a direct reduction shaft (1) having an in|et (2) for introduction of iron ore and an out|et (3) for removal of sponge iron, - a reducing gas in|et (4) for introduction of a reducing gas into the direct reduction shaft (1 ), -a reducing gas out|et (5) for removal of used reducing gas from the direct reduction shaft (1), wherein a reduction zone (6) of the direction reduction shaft is defined between a level of the reducing gas in|et (4) and the reducing gas out|et (5), -a c|eaning arrangement (7) for c|eaning used reducing gas, said c|eaning arrangement being connected to the reducing gas out|et (5) via a first gas line (8), -a second gas line (9) extending from the c|eaning arrangement (7) to the reducing gas in|et (4) for conducting cleaned reducing gas comprising hydrogen gas to the reducing gas in|et (4), -a heat exchanger (10) provided for heat exchange between used reducing gas in the first gas line (8) and cleaned reducing gas in the second gas line (9), -a cooling zone or cooling chamber (11) provided downstream the reduction zone (6) as seen in a flow direction of the iron ore and sponge iron, -a cooling gas in|et (12) for introduction of a cooling gas for cooling of sponge iron into the cooling zone or cooling chamber (11), -a cooling gas out|et (13) for removal of used cooling gas from the cooling zone or cooling chamber (11), said arrangement being characterised in that it comprises: -a third gas line (14) for conducting used cooling gas from the cooling gas outlet (13) to the first gas line (8) and mixing the used cooling gas with the used reducing gas at a mixing point (15) in the first gas line (8), the mixing point (15) being located upstream the heat exchanger (10) as seen in the flow direction of the reducing gas in the first gas line (8).

7. An arrangement according to claim 6, comprising a hydrogen gas source (16) and a gas line (17) for conducting hydrogen gas from the hydrogen gas source to the cooling gas inlet (12) of the cooling zone or cooling chamber (11).

8. An arrangement according to claim 6 or 7, wherein the cooling zone or cooling chamber (11) is defined by a cone-shaped lower part of the direct reduction shaft (1).

9. An arrangement according to any one of claims 6-8, comprising a heater (18) provided in the second gas line downstream the heat exchanger (10) as seen a flow direction of the reducing gas in the second gas line (9).