DEVICE FOR THE PRODUCTION OF CAST IRON

Abstract

DEVICE FOR THE PRODUCTION OF CAST IRON. The present invention relates to a device for the production of cast iron comprising a metallurgical vessel having a surrounding wall, a cyclone portion located on top of an ore reducing portion, the cyclone portion being in open connection with the ore reducing portion and having at least one feeding means around the circumference of the surrounding wall adjusted to introduce gaseous oxygen into the cyclone portion, wherein the at least one feeding means is further adjusted to introduce a mixture of gaseous oxygen and a fuel gas.

Description

1 / 7 Descriptive Report of the Invention Patent for a DEVICE FOR THE PRODUCTION OF CAST IRON.

[001] The present invention relates to a device for the production of cast iron comprising a metallurgical vessel having a surrounding wall, a cyclone portion located at the top of an ore reducing portion, the cyclone portion being in open connection with the ore reducing portion and having at least one feeding means around the circumference of the surrounding wall adjusted to introduce gaseous oxygen into the cyclone portion. The invention also relates to a method for the production of cast iron in a metallurgical vessel.

[002] Devices for the production of cast iron are known in the art. Document EP 0726 326 A1 describes such a device, which is also known as the HIsarna process by Tata Steel. Feeding means around the circumference of the surrounding wall adjusted to introduce gaseous oxygen are also known. For example, document EP 2794 931 B1 describes feeding means adjusted to introduce gaseous oxygen into the cyclone portion of the metallurgical vessel.

[003] Unfortunately, this type of metallurgical vessel, which has a cyclone portion and an ore-reducing portion, has the disadvantage that both portions cannot be controlled independently. In particular, temperature control within the metallurgical vessel is difficult, since both portions are in open connection with each other. This means that an adjustment in the ore-reducing portion influences the cyclone portion and vice versa.

[004] Temperature control in the reducing portion of ore is generally done by inserting a carbon-containing material into the slag layer. However, the insertion does not generate enough heat for the conversion of carbon, via carbon monoxide, into carbon dioxide. Petition 870220045544, dated 05 / 25 / 2022, page 7 / 27 2 / 7 carbon. The injection of gaseous oxygen into this portion generates sufficient energy and therefore heat, since it converts carbon monoxide into carbon dioxide. In order to maintain the temperature within the processing window in the cyclone portion, carbon-containing material can be added to the ore reducing portion at the desired rate. However, this can still lead to a lower than desired temperature in the cyclone portion, and the current way to resolve this is by adding even more gaseous oxygen to the ore reducing vessel. This, in turn, will lead to a temperature that can be too high in the ore reducing portion. The temperature balance between the cyclone portion and the ore reducing portion is therefore delicate, and both portions are not sufficiently controlled.

[005] The inventors, involved in finding more environmentally friendly solutions for the production of cast iron, discovered that this process could be controlled in a better way.

[006] The objective of the present invention is to provide a device and method that have better control over the process. An additional objective is to make better use of waste and produce less waste during the iron manufacturing process, with emphasis on reducing CO2 emissions per ton of pig iron.

[007] Consequently, a device and method for the production of pig iron is provided in which at least one feed medium is further adjusted to introduce a mixture of gaseous oxygen and a fuel gas. This has the advantage that the temperature control of the process in the cyclone portion is more independent of the temperature control in the ore reducing portion, since the introduction of the fuel gas together with the gaseous oxygen releases a great deal of energy during the combustion process. The feed medium is not particularly limited and can be a lance or an injector. By controlling the amount of fuel gas that is in Petition 870220045544, dated 05 / 25 / 2022, page 8 / 27 3 / 7 introduced, the energy and therefore the heat released in the process can also be controlled.

[008] Tests and simulations have proven that the introduction of fuel gas and gaseous oxygen with a predetermined mixture into the cyclone portion of the metallurgical vessel can be done without any additional adjustment. When fuel gas is introduced, it will introduce more heat just below the cyclone portion, leading to a higher temperature, especially in the cyclone portion, but at least partially also in the ore reducing portion. In this way, it will lead to better control over the cyclone portion of the metallurgical vessel, since the flow of both gases can be controlled and therefore a predetermined mixture can be introduced. Furthermore, the control of the flow and therefore the temperature will be more independent of the ore reducing portion.

[009] Fuel gas may be introduced into the cyclone portion or into the top of the ore reducing portion, or a combination thereof. If fuel gas is introduced into the top of the ore reducing portion, this will lead to partial combustion of the gas and therefore a smaller amount of coal required.

[0010] Preferably, the fuel gas is selected from the group of coking gas, converter gas, natural gas, hydrogen gas, and liquefied petroleum gas. Coking gas contains + / - 3% carbon dioxide, + / - 6% carbon monoxide, 60-65% hydrogen, + / - 3% nitrogen, and 25-30% methane. Converter gas consists of approximately 17-20% carbon dioxide, 60-65% carbon monoxide, + / - 1.5% hydrogen, and 15-20% nitrogen. The main requirement is that the nitrogen content of the fuel gas be relatively low, less than 20% (v / v). Thus, any fuel gas that has a low nitrogen content is suitable. Petition 870220045544, dated 05 / 25 / 2022, page 9 / 27 4 / 7 can be introduced. Temperature control will be better when the fuel gas is fully burned during the process.

[0011] The inventors found particularly good results with natural gas. Natural gas is predominantly methane (CH4), and the amount depends on the source. One advantage of using coking gas and converter gas is that they are sometimes considered waste, leading to unwanted emissions. Therefore, using these gases is a preferable option for combating climate change and reducing the amount of carbon dioxide in the atmosphere. The inventors feel a responsibility to act and do something, however small the steps, about climate change. They have a desire to make Earth a more sustainable place for future generations and, if possible, to make climate activists happy.

[0012] If natural gas is used in a mixture containing 25% natural gas and 75% gaseous oxygen, a reduction of up to 2% in CO2 emissions was calculated using a simulation program called the IRMA (IRon MAking) model. The IRMA program uses a flowchart design to decompose the entire process into building blocks. These building blocks are connected via material flow blocks. In this way, a complex process can be broken down into several simple steps. The calculations are based on a mixture of thermodynamic equilibrium relationships and empirical relationships. The thermodynamic calculations are performed by the ChemApp library, which also provides the library for the thermodynamic data. ChemApp is a product of GTTTechnologies and is based on the SimuSage package. The empirical theory is based on the cyclone converter mass and heat equilibrium model developed at Tata Steel (Corus).Most of the building blocks are validated using other model results or literature.

[0013] Another advantage of using natural gas is that the methane will Petition 870220045544, dated 05 / 25 / 2022, page 10 / 27 5 / 7 is converted, under processing conditions, into carbon dioxide and water. As is commonly known, methane is also a greenhouse gas and has an even greater greenhouse effect than carbon dioxide. In general, the addition of a combustible gas, such as natural gas, leads to a reduction in the use of coal. And therefore, less carbon dioxide will also be formed during the process, bringing the environmental benefits that the inventors seek.

[0014] Preferably, the feed media are distributed symmetrically along the circumference of the surrounding wall of the cyclone portion or at the top of the ore reducing unit. This is beneficial for good gas distribution within the cyclone portion of the metallurgical vessel and therefore also for temperature distribution. The top of the ore reducing unit is located at the top or near the roof of the ore reducing unit, just below the cyclone portion.

[0015] Preferably, the feed media are adjusted to mix the gaseous oxygen and the fuel gas before entering the cyclone portion. This is beneficial, since such pre-mixing increases the control of the mixture that is introduced into the cyclone portion of the metallurgical vessel.

[0016] Preferably, a group of gaseous oxygen outlets surrounds one or more fuel gas outlets. Preferably, a group of fuel gas outlets surrounds one or more gaseous oxygen outlets. These embodiments have the advantage that the mixture will be premixed immediately before being introduced into the cyclone portion, further improving control. An additional advantage is that the mixture will be uniformly distributed in the cyclone portion.

[0017] The invention will be elucidated below with reference to the drawing of an exemplary embodiment of a device that functions Petition 870220045544, dated 05 / 25 / 2022, p. 11 / 27 6 / 7 according to the invention, which does not limit the appended claims.

[0018] In the drawing: Figure 1 shows an overview of the metallurgical vessel; Figure 2 shows a top view of the feed media configuration in the cyclone portion wall;

[0019] In the figures, whenever the same reference numbers are applied, these numbers refer to the same parts.

[0020] Figure 1 shows an overview of the metallurgical vessel according to the process described in Patent Application EP-A-0 726 326 wherein, in a metallurgical vessel 1, a portion of cyclone 10 is applied to the top of the metallurgical vessel 1. Figure 1 clearly shows the introduction point 7 where gaseous oxygen or a mixture of gaseous oxygen and a fuel gas is injected into the ore-reducing cyclone 10 at the top of the metallurgical vessel 1. Figure 1 further shows the molten iron bath 2, a slag layer 3, the introduction points for carbon-containing material 5 and metal feed 4, iron outlet 8, slag outlet 9 and reaction gas outlet 11. For the present invention, only the introduction point for gaseous oxygen 7 or a mixture of gaseous oxygen and a fuel gas 7 is of importance.

[0021] Figure 2 shows, in a top view, an example of the position of the feed media 12 on the surrounding wall 13 of the cyclone portion 10. In this example, six feed media 12 are symmetrically distributed around the circumference of the surrounding wall 13 of the cyclone portion 10. This has been found to provide good results with regard to temperature control in the cyclone portion 10. Naturally, other configurations may be possible.

[0022] Although the invention has been discussed previously with Petition 870220045544, dated 05 / 25 / 2022, page 12 / 27 7 / 7 Regarding exemplary embodiments of the invention, the invention is not restricted to such particular embodiments, which can be varied in many ways without departing from the invention. The exemplary embodiments discussed should therefore not be used to interpret the appended claims strictly in accordance with them. Rather, the embodiments are intended only to explain the wording of the appended claims, without intending to limit the claims to such exemplary embodiments. The scope of protection of the invention should therefore be interpreted only in accordance with the appended claims, where any possible ambiguity in the wording of the claims should be resolved using such exemplary embodiments. Petition 870220045544, dated 05 / 25 / 2022, p. 13 / 27

Claims

1 / 2 CLAIMS 1. Device for producing cast iron comprising a metallurgical vessel (1), which has a surrounding wall (13), a cyclone portion (10) located at the top of an ore reducing portion, the cyclone portion (10) being in open connection with the ore reducing portion and having at least one feed means (7, 12) around the circumference of the surrounding wall (13) adjusted to introduce gaseous oxygen into the cyclone portion (10), said device being characterized in that the at least one feed means (7, 12) is further adjusted to introduce a mixture of gaseous oxygen and a fuel gas, the feed means (7, 12) being adjusted to mix the gaseous oxygen and the fuel gas before entering the cyclone portion (10).

2. Device according to claim 1, characterized in that the fuel gas is selected from the group of coking gas, converter gas, natural gas, gaseous hydrogen and liquefied petroleum gas.

3. Device according to claim 2, characterized in that the fuel gas contains less than 20% (v / v) of gaseous nitrogen.

4. Device according to any one of claims 1 to 3, characterized in that the feed medium (7, 12) is distributed symmetrically along the circumference of the surrounding wall (13) of the cyclone portion (10).

5. Device, according to any one of claims 1 to 5, characterized in that the feeding means (7, 12) is configured so that a set of gaseous oxygen outlets is surrounded by one or more fuel gas outlets. Petition 870260053461, dated 02 / 06 / 2026, page 18 / 46 2 / 2 6. Device for the production of cast iron, according to any one of claims 1 to 5, characterized in that the feeding means (7, 12) are configured in such a way that a set of fuel gas outlets is surrounded by one or more gaseous oxygen outlets.

7. Method for producing cast iron by means of a metallurgical vessel (1), which has a surrounding wall (13), a cyclone portion (10) located at the top of an ore reducing portion, the cyclone portion (10) being in open connection with the ore reducing portion and having at least one feed means (7, 12) around the circumference of the surrounding wall (13) which introduces gaseous oxygen into the cyclone portion (10), said method being characterized in that a mixture of gaseous oxygen and a fuel gas is introduced through at least one feed means (7, 12), the gaseous oxygen and the fuel gas being mixed by the feed means (7, 12) before entering the cyclone portion (10).

8. Method according to claim 7, characterized in that the fuel gas is selected from the group of coking gas, converter gas, natural gas, gaseous hydrogen and liquefied petroleum gas.

9. Method according to claim 7 or 8, characterized in that the fuel gas contains less than 20% (v / v) of gaseous nitrogen.

10. Method, according to any one of claims 7 to 9, characterized in that the feeding means (7, 12) are symmetrically distributed along the circumference of the surrounding wall (13) of the cyclone portion (10). Petition 870260053461, dated 02 / 06 / 2026, p. 19 / 46

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