US 6,187,076 B1Granted

Fluidized bed reduction method, fluidized bed reduction reactor, and fluidized bed reduction system

AssigneesKabushiki Kaisha Kobe Seiko Sho, Midrex Corporation

InventorsTakayuki Sugahara, Ryoichi Hata, Shintaro Ano, Kenji Ohiraki, Gilbert Yould Whitten, Jr.

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Abstract

A fluidized bed reduction method in which powder raw material, including powder ore or partially pre-reduced powder ore, forms a fluidized bed with, and is sequentially reduced by reducing gas while being moved between a plurality of fluidized bed chambers; and to a fluidized bed reduction reactor which can be used in the same method. The movement of the powder ore between the fluidized bed chambers is carried out giving priority to relatively larger powder particles with the aim of improving the stability of the fluidized bed in the fluidized bed chambers. The adjustment of the reducing power of each fluidized bed chamber is made possible by introducing the reducing gas into the fluidized bed chambers in parallel, whereby an increase in the degree of reduction of the raw material can be realised.

Claims20

Dependent claims

A fluidized bed reduction method comprising the steps of:

supplying reducing gas into a plurality of chambers connected with one another in a series through a plurality of supply lines connected with the plurality of chambers, respectively, each chamber being supplied with reducing gas through the corresponding supply line at a predetermined supply rate;
introducing powder raw material into a first chamber of the plurality of chambers to produce a fluidized bed of powder raw material in the first chamber owing to the supplied reducing gas;
allowing powder raw material to move from the first chamber to the subsequent chambers while producing a fluidized bed of powder raw material in each subsequent chamber, the powder raw material being moved from one chamber to next chamber at a position lower than a top of the fluidized bed formed in each chamber;
controlling the supply amount of reducing gas to each chamber in accordance with a reducing state of the powder raw material in each chamber;
and
discharging reduced material from at least one chamber of the plurality of chambers.

3 more elements

A fluidized bed reduction system comprising:

a fluidized bed reduction reactor including:
a plurality of fluidized bed chambers connected with one another in a series, and having at least a first fluidized bed chamber and a last fluidized bed chamber, a space of one fluidized bed chamber being communicated with a space of next fluidized bed chamber at a position lower than a top of a fluidized bed formed in each of the two fluidized bed chambers,
a plurality of reducing gas supply lines respectively connected with the plurality of fluidized bed chambers for each supplying reducing gas to the corresponding fluidized bed chamber, each reducing gas supply line being provided with a supply controller for controlling the supply amount of reducing gas to the corresponding fluidized bed chamber;
an inlet for introducing a powder raw material in the first fluidized bed chamber,
an outlet for removing the powder raw material reduced in the fluidized beds provided in the last fluidized bed chamber;
a pre-reducing chamber which is connected with the reactor and into which the exhausted reducing gas is flowed from the reactor, the reactor chamber having;
an inlet port for receiving the powder raw material;
and
an outlet port for flowing the powder raw material out of the pre-reducing chamber,
a connection passage between the outlet port of the pre-reducing chamber and the inlet of the reactor,
whereby the powder raw material being pre-reduced by the exhausted reducing gas from the reactor.

8 more elements

Dependencies are inferred from the claim text.