LU82530A1 - METHOD FOR CONDUCTING A TANK OVEN - Google Patents

Description

, ". »S. · / · 1% Claim of the priority of a 1 patent application filed in Belgium IT "on 21.6.1979 under No 877.174 C 1963/7906.

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PATENT

METALLURGICAL RESEARCH CENTER -CENTRUM VOOR RESEARCH IN DE METALLURGIE,

Non-profit association - Vereniging zonder winstoogmerk in BRUXELLES, (Belgium).

Method for operating a pot furnace.

. The present invention relates to the operation of tank ovens, and more particularly, but not exclusively, of blast furnaces for the production of .fonte.

For several years, ever greater quantities of hydrocarbons, such as fuel oil or natural gas, have been injected into the blast furnace in order to reduce the consumption of coke. However, these injections have a cooling character and high wind temperatures have been used to keep a sufficient flame temperature.

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Under the current circumstances, the price of hydrocarbons is constantly increasing and it is not excluded that supply difficulties may arise.

Any reduction in the quantities of hydrocarbons injected into the blast furnace, while maintaining a temperature of. high wind, however, would lead to excessive flame temperatures and a significant heat deficit at the top.

From a strictly thermal point of view, it would be possible to replace these injections of hydrocarbons with other cooling injections, for example steam, in order to maintain high wind temperatures. The latter is however very expensive and its production requires the consumption of large amounts of energy. In addition, such an injection leads to an increase in the placing per mile of coke from 25 to 30 kg per tonne of pig iron.

The industry therefore needs a process for controlling blast furnaces which, while retaining the high wind temperatures currently practiced, makes it possible to minimize the overall energy consumption of the process.

In the course of his research with a view to developing a process meeting this need, the applicant has now discovered that it is possible to maintain such high wind temperatures, even in the absence of injections of hydrocarbons, by reducing the oxygen content of the wind.

The process which is the subject of the present invention is therefore essentially characterized in that the oxygen content of the blown wind in the blast furnace is reduced by adding to the said wind a gaseous fluid having an oxygen content lower than that of the says wind.

According to a preferred implementation of the process of the invention, the said gaseous fluid is introduced, without / pressure, into the air sucked in by the blower.

tJ * - "7 * _ I ': i - I A particularly advantageous method of implementing the method of the invention consists in introducing into the wind combustion fumes rich in nitrogen, for example from cowpers.

* Another interesting method of implementing this process consists in introducing nitrogen into the wind, for example from an oxygen production installation.

/ As an example of implementation of the process of the invention, the table below illustrates the results obtained * with fuel injection, without injection, or with addition of nitrogen or cowpers fumes, respectively. The top temperature is kept constant at 125 ° C.

Inj. t ° Inj. Inj.

fuel wind N2 smoke coke kg / tf 404 507 464 488

Wind temperature 'c 1250' 934 1250 1250

Injections. fuel quantity kg / tf 60 N2 quantity m3N / tf - - 195 temperature ° C - - 1250

Smoke quantity m ^ N / tf - - - 135 cowpers temperature ° C - - - 1250

Shutter temperature ° C 125 125 125 125

This example clearly shows the advantage of the invention, with regard to the placing of coke in the middle, when the injection of hydrocarbons into the upper furnace is suppressed. / neau.

Claims (3)

2. Method according to claim 1, characterized in that said gaseous fluid consists essentially of nitrogen. 3. Method according to claim 1, characterized in that said gaseous fluid consists of combustion fumes. 4. Method according to either of claims 1 to 3, characterized in that said gaseous fluid is added to the air sucked in by the blower. U _____ 1 "y v