Specialized metallurgical processes – compositions for use therei – Processes – Producing or treating free metal
Patent
1997-11-26
2000-03-28
Kastler, Scott
Specialized metallurgical processes, compositions for use therei
Processes
Producing or treating free metal
75512, 266208, C21C 710
Patent
active
060426330
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a method for after combustion of reaction gases resulting from the decarburization of liquid steel in reaction vessels under vacuum.
In DE 41 30 590 C2 a degassing vessel is provided as a reaction vessel for the vacuum treatment of liquid steel. In this printed document it is disclosed that particles are entrained by a degassing current of the reaction gases which leads to a pronounced deposit formation of steel splashes in the upper part of the reaction vessel and in the area of the connecting line to the vacuum pump. Such steel deposits may have a considerable weight and finally may almost close off the upper end of the reaction vessel so that, in general, such steel deposits must be removed in a complicated manner by melting.
For avoiding the formation of such steel deposits, a method is suggested in EP 0 347 884 B1, which defines the closest prior art, to the instant invention with which an after combustion of the resulting reaction gases is desired. In the context of this known method, oxygen or an oxygen containing gas is blown via a pipe insertable to a defined spacing above the surface of the liquid steel within the steel bath in an amount to be calculated. With this known method three effects are to be achieved jointly, i.e., the decarburization of the steel by supplying oxygen, a heating of the steel bath, as well as an after combustion of the reaction gases resulting from the vacuum treatment. In practice, it was shown that with the known method the prevention of steel deposits especially in elongate, respectively, tall reaction vessels cannot be prevented sufficiently reliably.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to improve a method of the aforementioned kind such that the danger of formation of steel deposits in the reaction vessel can be further reduced. Furthermore, a device is to be disclosed that is suitable for performing the improved method.
The solution to this object, including advantageous embodiments and developments, can be taken from the disclosure of the specipication.
The invention is based on the principle that a stream of air is introduced counter to the flow direction of the reaction gases via the blow-in opening into the reaction vessel, whereby the blow-in opening is arranged within the refractory lining. With the invention it is advantageously achieved that due to the supply of air an excellent after combustion of the reaction gases takes place so that, due to the resulting heat, the formation of steel deposits can be prevented.
According to a preferred embodiment of the invention, it is suggested that the air is introduced as hot air with a temperature between 800.degree. C. to 1400.degree. C. This has the advantage that the hot air, due to its own high blow-velocity, has a substantially higher energy impulse and accordingly penetrates in the direction of length/height of the reaction vessel, counter to the flow direction of the reaction gases, very deeply into the reaction vessel. This results in a sufficiently strong mixing turbulence of the reaction gases and the hot air stream which results in an improved combustion of the reaction gases and in an improved heat transfer to the inner side of the wall of the reaction vessel. The reason for this is that the air under conventional conditions can be introduced into the reaction vessel only with maximally the speed of sound. For cold air this speed of sound is only 330 m/sec. while the speed of sound for air at a temperature of, for example, 1200.degree. C. is approximately 800 m/sec. By using hot air, it is thus possible to introduce the air into the reaction vessel at substantially increased velocity.
In a simplified manner, the introduction of air into the reaction gases in the reaction vessel results in an elongate, large flame which can be controlled by the amount of air as well as by the velocity of air being blown in. By providing such a large flame it is possible to melt quickly even existing large steel deposits. Advantageously,
REFERENCES:
patent: 4979983 (1990-12-01), Nishikawa et al.
patent: 5571307 (1996-11-01), Sizov et al.
Brotzmann Karl
Holtermann Heinz
Kastler Scott
Technometal Gesellschaft fur Metalltechnologie mbH
LandOfFree
Process for post-combustion of reaction gases produced during th does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for post-combustion of reaction gases produced during th, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for post-combustion of reaction gases produced during th will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1322450