Specialized metallurgical processes – compositions for use therei – Processes – Producing or treating free metal
Patent
1998-07-29
2000-10-03
Andrews, Melvyn
Specialized metallurgical processes, compositions for use therei
Processes
Producing or treating free metal
266160, C21B 506
Patent
active
061267171
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATION
This is the 35 USC 371 national stage of international application PCT/FR97/00175 filed on Jan. 29, 1997, which designated the United States of America.
FIELD OF THE INVENTION
The present invention relates to a ferrous metallurgical process, of the type in which air is separated in an air separation unit, oxygen thus produced is consumed in at least one step of the ferrous metallurgical process, a gas from this ferrous metallurgical process is partially decarbonted, and this partially decarbonated gas is used to carry out a reduction reaction of the ferrous metallurgical process, the partial decarbonation comprising, in a cyclical manner, a phase of fixation of CO.sub.2 by a fixation product, then a phase of regeneration of this product in a reactor.
BACKGROUND OF THE INVENTION
A process of this type is at present known under the mark "COREX" of the Austrian company VOEST-ALPINE INDUSTRIES ANLAGENEBAU.
Other examples of processes of this type are the process HyL III commercialized by the Mexican company HYLSA, or the all-oxygen blast furnace process introduced by the Japanese company NKK.
The solutions that have been proposed to carry out the partial decarbonation of the mentioned gas are either a washing with amines, or a selective adsorption with pressure variation and with vacuum. In the first case, the regeneration of the washing solution uses large quantities of steam, and in the second gas, the vacuum pumps required are expensive as to cost and energy consumption.
SUMMARY OF THE INVENTION
The invention has for its object to improve the economy of the partial decarbonation. To this end, it has for its object a process of the mentioned type, characterized in that in the course of the regeneration phase of the product of fixation, there is introduced into the reactor nitrogen produced by the air separation unit.
The process according to the invention can comprise one or several of the following characteristics: regeneration tower for this solvent into which nitrogen is introduced; methyldiethylamine (MDEA), and the regeneration tower comprises at its base a steam reboiler and at its head a water condenser; Swing Adsorption) process, particularly with four adsorbers, the nitrogen being introduced countercurrent into the adsorber, during its regeneration, in an elution step of the latter at the low pressure of the PSA cycle; with nitrogen followed by a countercurrent elution step with a gas withdrawn co-currently from another adsorber in the course of decompression; 50.degree. C.; direct reduction of iron mineral, said gas being gas resulting from the gasification and/or ass resulting from the direct reduction of the iron mineral.
The invention also has for its object a ferrous metallurgical installation adapted to practice the process defined above. This installation, of the type comprising at least a first oxygen consuming apparatus, a second apparatus, if desired distinct from the first, producing a gas which contains CO.sub.2, a partial decarbonation unit for this gas, a third apparatus, if desired separate from the first and/or second apparatus, in which is carried out a reduction reaction, means to supply to this third apparatus the partially decarbonated gas, and an air separation unit adapted to produce the oxygen necessary for said first apparatus, the partial decarbonation unit comprising means for fixing CO.sub.2 by a fixation product and means for regenerating this product, is characterized in that the nitrogen outlet of the air separation unit is connected to the regeneration means of the fixation product.
According to other characteristics of this installation: and means to circulate a solvent for the CO.sub.2 from the adsorber to the tower and vice versa, the tower comprising a nitrogen inlet connected to the nitrogen outlet of the air separation unit; Adsorption) which comprises means for selective connection of the outlet of each adsorber to the nitrogen outlet of the air separation unit; means.
BRIEF DESCRIPTION OF THE DRAWINGS
Examples
REFERENCES:
patent: 5244489 (1993-09-01), Grenier
patent: 5268019 (1993-12-01), Rathbone
patent: 5582029 (1996-12-01), Occhialini et al.
Gauthier Pierre
Jutard Jerome
Vigor Xavier
Andrews Melvyn
L'Air Liquide Societe Anonyme pour l'Etude et, l'Exploitation de
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