LU85585A1 - PROCESS FOR INJECTING REDUCING GAS IN THE BLAST FURNACE - Google Patents

Description

"Τ τ * / C 2271/8310.

METALLURGICAL RESEARCH CENTER -CENTRUM V00R RESEARCH IN DE METALLURGIE #

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

Process for injecting reducing gas into the blast furnace.

The present invention relates to a process for injecting reducing gas into a blast furnace, “in order to promote the reduction of iron ore therein.

This method is especially intended to be applied in the context of the blast furnace control methods already described by the applicant in previous patents.

The process of the invention is particularly suitable for the production of reducing gases from solid fuel. In our context # the term solid fuel includes any material with a high carbon content # be it ma-

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g v. * ._ / ~~ 2.- or residues from other industrial operations such as pitch, petroleum coke, ...

In the current economic situation, the production of reducing gas from solid fuel is of definite interest as a palliative for the use of petroleum products and natural gases; because of their price, they can only lead to profitable exploitation in a minority of cases, which explains why many steelmakers are again turning to coal. Processes have been developed to replace a non-negligible part of the metallurgical coke by direct injection of coal into the blast furnace nozzles. A new process developed by the applicant consists in injecting reducing gases into the nozzles, these mainly containing 'CO, H2 and possibly N2, and in smaller quantities of CO2 and H2O and being obtained from solid fuel , preferably dried and finely ground, and then injected into a reactor where it is gasified.

By applying this technique, superheated reducing gases are obtained at the nose of the nozzle, containing only the fuel ashes and a relatively small portion of unburnt materials.

By continuing his research, the Applicant found that the efficiency of the injection operation could be improved by modifying the conditions for producing the injected gas.

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The process of injecting reducing gas into the blast furnace, object of the present invention, in which a reducing gas is produced from solid fuel, preferably dried and finely ground, is essentially characterized in that J is blown in mixture carbon in the gaseous state and hot wind, the latter possibly being over-oxygenated.

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According to a method of implementing the process of the present invention, the products from the reactor, carbon in the gaseous state being one of these products, have an enthalpy corresponding to a temperature above 3500 ° C.

In a preferred implementation of the process of the invention, the carbon in the gaseous state is produced by treatment of the solid fuel in a reactor comprising a plasma torch.

According to one embodiment of this variant of the process of the invention, the products leaving the reactor containing the torch are given an enthalpy corresponding to a temperature above 3500 ° C., by modulating the electrical energy 4 of the torch plasma based on the flow rate and the nature of solid combustible materials and gases necessary for its operation.

According to yet another embodiment of this variant of the process of the present invention, the solid fuels are introduced into the plasma torch upstream of the place where the electric arc is born and pass through said torch.

In a particular implementation of the method of the present invention, the gas introduced into the plasma torch for operating purposes, is air.

Claims (6)

1. A method of injecting reducing gas into the blast furnace, in which a reducing gas is produced from solid fuel, preferably dried and finely ground, characterized in that carbon is blown in the gaseous state and the wind ? hot, the latter possibly being over-oxygenated. f i 2. Method according to claim 1, characterized in that the products from the reactor, carbon in the gaseous state being one of these products, have an enthalpy corresponding to a temperature above 3500 ° C. 3. Method according to claims 1 or 2, characterized in that the carbon in the gaseous state is produced by treatment of solid fuel in a reactor comprising a plasma torch. 4. Method according to claim 3, characterized in that one confers on the products at the outlet of the reactor containing the torch, an enthalpy corresponding to a temperature higher than 3500 ° C, by modulating the electrical energy of the plasma torch in depending on the flow rate and the nature of solid combustible materials and gases necessary for its operation. 5. Method according to claims 3 or 4, characterized in that the solid fuels are introduced into the plasma torch upstream of the place where the electric arc arises and travels / feels said torch. i! î ΊΤ i 5.- 6. Method according to one or more of claims 1 to 5, characterized in that the gas introduced into the plasma torch for its operation is air. d / *) / -