Equipment for producing molten iron

Abstract

An apparatus for producing molten iron comprises a metallurgical vessel having an enclosure wall, a cyclone portion disposed on top of a smelter reduction portion, the cyclone portion being openly connected to the smelter reduction portion and having at least one supply device surrounding a periphery of the enclosure wall, the at least one supply device is adjusted to introduce oxygen into the cyclone portion, wherein the at least one supply device is further adjusted to introduce a mixture of oxygen and combustible gas.

Description

[0001] This application is a divisional application of the invention patent application entitled "Equipment for Producing Molten Iron", with an international application date of November 27, 2020, an international application number of PCT / EP2020 / 083697, and a national application number of 202080090454.6. Technical Field

[0002] The present invention relates to an apparatus for producing molten iron, the apparatus comprising a metallurgical vessel having a surrounding wall, a cyclone section arranged on top of a smelting reduction section, the cyclone section being openly connected to the smelting reduction section and having at least one supply device around the periphery of the surrounding wall, the supply device being adjusted to introduce oxygen into the cyclone section. The invention also relates to a method for producing molten iron in a metallurgical vessel. Background Art

[0003] Apparatus for producing hot metal is known in the art. EP 0 726 326 A1 describes such an apparatus, which is also known as the Hlsarna process of Tata Steel. Supply means regulated to introduce oxygen around the periphery of the enclosure are also known. For example, EP 2 794 931 B1 describes a supply means regulated to introduce oxygen into the cyclone portion of a metallurgical vessel.

[0004] Disadvantageously, a metallurgical vessel of this type having a cyclone section and a smelting reduction section has the disadvantage that the two sections cannot be controlled in an independent manner. In particular, temperature control within the metallurgical vessel is difficult, since the two sections are openly connected to each other. This means that adjustments in the smelting reduction section affect the cyclone section and vice versa.

[0005] Temperature control in the smelting reduction section is usually controlled by adding carbonaceous materials to the slag layer. However, this addition does not generate enough heat for the conversion from carbon to carbon dioxide via carbon monoxide. The injection of oxygen in this section does generate enough energy, and therefore enough heat, because it converts carbon monoxide into carbon dioxide. In order to maintain the temperature within the processing window in the cyclone section, carbonaceous materials can be added in the smelting reduction section at a desired content. However, this may still lead to a lower than desired temperature in the cyclone section, and the current way to solve this problem is by adding more oxygen in the smelting reduction vessel. This in turn will lead to a temperature that may be too high in the smelting reduction section. Therefore, the temperature balance between the cyclone section and the smelting reduction section is a delicate balance, and neither of these two parts can be controlled well enough. Summary of the invention

[0006] The inventors, in their search for a more environmentally friendly solution for producing molten iron, discovered that the process could be controlled in a better way.

[0007] The object of the present invention is to provide an apparatus and a method with better control of the process. Another object is to make better use of waste and to generate less waste in the ironmaking process, with an emphasis on reducing CO per ton of hot metal. 2 emissions.

[0008] Thus, an apparatus and method for producing molten iron is provided, wherein at least one supply device is further adjusted to introduce a mixture of oxygen and combustible gas. This has the advantage that the temperature control of the process in the cyclone section is more independent of the temperature control of the smelting reduction section, because introducing combustible gas together with oxygen releases a large amount of energy during the combustion process. The supply device is not particularly limited and can be a lance or an injector. By controlling the amount of combustible gas introduced, it is also possible to control the energy released in the process, and therefore the heat released in the process.

[0009] Tests and simulations have demonstrated that the introduction of combustible gas and oxygen in a predetermined mixture in the cyclone section of the metallurgical vessel can be carried out without any further regulation. When the combustible gas is introduced, more heat will be introduced directly below the cyclone section, resulting in higher temperatures, especially in the cyclone section, but at least partly also in the smelting reduction section. In this way, a better control of the cyclone section of the metallurgical vessel will result, since the flow of both gases can be controlled and thus a predetermined mixture can be introduced. Furthermore, the control of the flow rates and therefore the temperature will be more independent of the smelting reduction section.

[0010] The combustible gas may be introduced in the cyclone section, or at the top of the smelting reduction section, or a combination of both. If the combustible gas is introduced at the top of the smelting reduction section, this will result in partial combustion of the gas and therefore a lower reduction in coal demand.

[0011] Preferably, the combustible gas is selected from the group of coke oven gas, converter gas, natural gas, hydrogen and liquefied petroleum gas. Coke oven gas contains + / -3% carbon dioxide, + / -6% carbon monoxide, 60-65% hydrogen, + / -3% nitrogen and 25-30% methane. Converter gas generally comprises 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 combustible gas should be relatively low, less than 20% (v / v). In this way, any combustible gas with a low nitrogen content can be introduced. Temperature control is optimal when the combustible gas is completely burned during the process.

[0012] The inventors have found particularly good results with natural gas. Natural gas is primarily methane (CH 4), and its content depends on the source. The advantage of using coke oven gas and converter gas is that they are sometimes considered waste materials that cause undesirable emissions. Therefore, using these gases is a preferred option to prevent climate change and reduce the amount of carbon dioxide in the atmosphere. The inventors feel a responsibility to take action on climate change and do something, no matter how small the improvement. If possible, they hope to create a more sustainable planet for future generations, which will comfort climate activists.

[0013] If natural gas is used in a mixture containing 25% natural gas and 75% oxygen, the CO is calculated by a simulation program called the IRMA (Ironmaking) model. 2 Up to 2% reduction in emissions. The IRMA program uses a flow chart design to decompose the entire process in building blocks. These building blocks are connected by logistics modules. In this way, a complex process can be divided into many simple steps. The calculations are based on a mixture of thermodynamic equilibrium relations and empirical relations. Thermodynamic calculations are performed by the ChemApp library, which also provides libraries for thermodynamic data. ChemApp is a product of GTTTechnologies and is based on the SimuSage package. The empirical theory is based on the "Cyclone-converter heat and mass balance model" developed at Tata Steel (Corus). Most of the building blocks are validated using other model results or literature.

[0014] Another advantage of using natural gas is that methane will be converted into carbon dioxide and water under the process conditions. It is well known that methane is also a greenhouse gas and has a greater greenhouse effect than carbon dioxide. Generally, the addition of a combustible gas such as natural gas results in a reduction in the use of coal. Therefore, less carbon dioxide will also be formed in the process, bringing the environmental benefits sought by the inventors.

[0015] Preferably, the supply means are symmetrically distributed over the periphery of the surrounding wall of the cyclone section or at the top of the smelting reduction unit. This facilitates good gas distribution within the cyclone section of the metallurgical vessel and thereby also facilitates temperature distribution. The top of the smelting reduction unit is located at or near the top of the smelting reduction unit, directly below the cyclone section.

[0016] Preferably, the supply means is adjusted to mix the oxygen and the combustible gas before they enter the cyclone section. This is beneficial because such pre-mixing increases control over the mixture introduced into the cyclone section of the metallurgical vessel.

[0017] Preferably, a group of oxygen outlets surround one or more combustible gas outlets. Preferably, a group of combustible gas outlets surround one or more oxygen outlets. These embodiments all have the advantage that the mixture is premixed just before being introduced into the cyclone section, further improving control. Another advantage is that the mixture will be evenly distributed in the cyclone section. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will be further elucidated below with reference to the accompanying drawings of an exemplary embodiment of an apparatus operating according to the invention, which exemplary embodiment does not limit the appended claims.

[0019] In the figure:

[0020] Figure 1 A general diagram of a metallurgical vessel is shown;

[0021] Figure 2 a top view showing the configuration of the supply means in the wall of the cyclone section;

[0022] When the same reference numerals are used in the drawings, they refer to the same parts. DETAILED DESCRIPTION

[0023] Figure 1 A general view of a metallurgical vessel according to the process disclosed in patent application EP-A-0 726 326 is shown, wherein a metallurgical vessel 1 is provided with a cyclone section 10 on top of the metallurgical vessel 1 . Figure 1 The introduction point 7 where oxygen or a mixture of oxygen and combustible gas is injected into the smelting cyclone 10 at the top of the metallurgical vessel 1 is clearly shown. Figure 1 Also shown are the molten iron pool 2, slag layer 3, introduction points for carbonaceous material 5 and metalliferous feed 4, tap hole 8, slag hole 9 and reaction gas outlet 11. For the present invention, only the introduction point for oxygen 7 or a mixture of oxygen and combustible gas 7 is important.

[0024] Figure 2 An example of the location of supply means 12 in the surrounding wall 13 of the cyclone portion 10 is shown in top view. In this example, six supply means 12 are symmetrically distributed around the circumference of the surrounding wall 13 of the cyclone portion 10. Such an arrangement has been found to give good results in controlling the temperature in the cyclone portion 10. Of course, other arrangements are possible.

[0025] Although the present invention has been discussed above with reference to exemplary embodiments of the present invention, the present invention is not limited to these specific embodiments, which can be changed in many ways without departing from the present invention. Therefore, the exemplary embodiments discussed should not be used to strictly interpret the attached claims. On the contrary, the embodiments are only intended to interpret the wording of the attached claims, rather than to limit the claims to these exemplary embodiments. Therefore, the scope of protection of the present invention should be interpreted only according to the attached claims, and possible ambiguities in the wording of the claims should be resolved using these exemplary embodiments.

Claims

1. An apparatus for producing molten iron, comprising a metallurgical vessel (1), the metallurgical vessel (1) having a surrounding wall (13), a cyclone section (10) arranged on top of a smelting reduction section, the cyclone section (10) being openly connected to the smelting reduction section and having at least one supply device (7, 12) around the periphery of the surrounding wall (13), the at least one supply device (7, 12) being adjusted to introduce oxygen into the cyclone section (10), It is characterized in that The at least one supply device (7, 12) is further adjusted to introduce a mixture of oxygen and combustible gas, wherein the supply devices (7, 12) are symmetrically distributed on the periphery of the surrounding wall (13) of the cyclone part (10), and the supply devices (7, 12) are adjusted to mix the oxygen and the combustible gas before entering the cyclone part (10), and the supply devices (7, 12) are configured so that a group of oxygen outlets are surrounded by one or more combustible gas outlets, or a group of combustible gas outlets are surrounded by one or more oxygen outlets.

2. The apparatus for producing molten iron according to claim 1, It is characterized in that The combustible gas is selected from the group consisting of coke oven gas, converter gas, natural gas, hydrogen and liquefied petroleum gas.

3. The apparatus for producing molten iron according to claim 2, It is characterized in that The combustible gas contains less than 20% (v / v) nitrogen.

4. The apparatus for producing molten iron according to any one of claims 1 to 3, It is characterized in that The supply device (7, 12) is also located at the top of the smelting reduction section.

5. The apparatus for producing molten iron according to any one of claims 1 to 4, It is characterized in that The supply devices (7, 12) are symmetrically distributed on the periphery of the surrounding wall (13) at the top of the smelting reduction section.

6. A method for producing molten iron by means of a metallurgical vessel (1), the metallurgical vessel (1) having a surrounding wall (13), a cyclone section (10) arranged on top of a smelting reduction section, the cyclone section (10) being openly connected to the smelting reduction section, and having at least one supply device (7, 12) around the periphery of the surrounding wall (13), the supply device (7, 12) introducing oxygen into the cyclone section (10), It is characterized in that A mixture of oxygen and combustible gas is introduced through the at least one supply device (7, 12), wherein the supply devices (7, 12) are symmetrically distributed on the periphery of the surrounding wall (13) of the cyclone part (10), and the supply devices (7, 12) are adjusted to mix the oxygen and the combustible gas before entering the cyclone part (10), and the supply devices (7, 12) are configured so that a group of oxygen outlets are surrounded by one or more combustible gas outlets, or a group of combustible gas outlets are surrounded by one or more oxygen outlets.

7. The method for producing molten iron according to claim 6, It is characterized in that The combustible gas is selected from the group consisting of coke oven gas, converter gas, natural gas, hydrogen and liquefied petroleum gas.

8. The method for producing molten iron according to claim 6, It is characterized in that The combustible gas contains less than 20% (v / v) nitrogen.

9. The method according to any one of claims 6 to 8, It is characterized in that The supply device (7, 12) is also located at the top of the smelting reduction section.

10. The method for producing molten iron according to claim 9, It is characterized in that The supply devices (7, 12) are symmetrically distributed on the periphery of the surrounding wall (13) at the top of the smelting reduction section.

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