Burner process for iron-fueled combustion equipment.

Abstract

Burner process for burning iron fuel, 2-15kg / Nm 3 , more preferably 4 to 8 kg / Nm 3 introducing said iron fuel suspension medium into an iron fuel burner apparatus at a velocity of between 5.5 and 55 m / s, more preferably between 20 and 40 m / s; introducing air into said iron fuel burner apparatus through an air inlet means, said air from said air inlet means being introduced at an overall angular momentum ratio between said air and said iron fuel suspension medium of between 3 and 12, more preferably between 3.8 and 8.9; exposing and mixing said iron fuel suspension medium with said air to obtain a combustible medium within said burner apparatus such that an overall oxygen to fuel equivalence ratio is obtained of between 1.0 and 2.5, more preferably between 1.2 and 1.8; and igniting the combustible medium to provide a burning iron fuel containing medium.

Description

[Technical field]

[0001] The present invention relates to a burner process for burning iron fuel. [Background technology]

[0002] Energy is essential. The amount of energy consumed worldwide has increased exponentially over the past few decades. Although the amount of energy generated from renewable sources such as wind and solar has increased over the past few decades and especially over the past few years, the majority of energy still comes from fossil fuels.

[0003] The use of fossil fuels also results in the highly undesirable emission of carbon dioxide, CO2. And to achieve climate objectives, the total emission of CO2 should be significantly reduced. To this end, carbon-neutral fuels, and moreover carbon-free fuels, are preferred energy sources and promising resources for meeting global energy requirements while achieving climate objectives. Carbon-neutral fuels are considered fuels that do not release more carbon into the atmosphere than they remove, while carbon-free fuels do not produce net greenhouse gas emissions or produce a carbon footprint. Typically, carbon-neutral fuels do not emit CO 2または Other greenhouse gases are used as feedstocks.

[0004] Heat-intensive industries account for a large proportion of total CO2 emissions. However, many industries are scalable on the one hand and can provide sufficient energy with high certainty and consistency on the other hand, while NO x There are currently few or no low-emission, and therefore zero-CO2, alternatives to fossil fuels available.

[0005] Solar and wind energy can partially meet this need, however, due to the fact that they are intermittent, they are often unsuitable or insufficient to replace fossil fuels and constantly meet the energy demands from these industries.

[0006] Therefore, in recent years, much research has been conducted into viable alternatives that do not emit CO2 at all, and iron fuel has the potential and potential of choice to meet that need.

[0007] Iron fuel is a very promising fuel in which energy is stored in iron powder when and where it is needed. Under the right conditions, iron powder is combustible, and when it burns, a large amount of energy is released in the form of heat, emitting no CO2 and less NO than alternative fuels. x It has the property of being low-emission. This heat can then be converted into hot water, steam or electricity for use in any kind of application or industry. Another important property of iron powder is that only rust remains during combustion and no CO2 is released during the combustion of iron powder. The product rust can be collected in a sustainable way and converted back into iron powder, making it a fully circular process.

[0008] The fact that iron fuel is CO2-free, circular, easy to store and transport, safe and cheap makes it an ideal clean and sustainable alternative to fossil fuels to meet the energy needs of various industries as well as all kinds of other applications.

[0009] The use of iron fuel can be a proven clean and sustainable alternative to fossil fuels, but it does present some challenges. One of the challenges is to maximize the heat release without compromising the quality of the rust obtained, as it will be converted back into iron fuel. It is therefore necessary to improve the known burner process suitable for iron fuel combustion so that the energy generated is optimized, but on the other hand the burner process is controlled in an optimal way to collect the rust as a lumber product, so that it can be easily collected and converted back into iron powder in a sustainable way, thus making it a fully circular process.

[0010] It is an object of the present invention to provide an improved burner process for iron fuel combustion.

[0011] A further object of the present invention is to provide an improved burner process for iron fuel combustion with effective and efficient energy generation from the burner process, where rust can be collected and returned to iron powder in an improved and sustainable manner, while pollution of the burner process is kept to a minimum. Summary of the Invention

[0012] In a first aspect, the present invention provides a burner process for iron fuel combustion, comprising: (a) 2~15kg / Nm 3 , more preferably 4 to 8 kg / Nm 3 providing an iron fuel suspension medium comprising iron fuel and oxygen at a suspended solids density of (b) introducing the iron fuel suspension medium into the iron fuel burner apparatus at a velocity of 5.5 to 55 m / s, more preferably 20 to 40 m / s; (c) introducing air into the iron fuel burner apparatus through an air inlet means, the air from the air inlet means being introduced with an overall angular momentum ratio between the air and the iron fuel suspension medium of between 3 and 12, more preferably between 3.8 and 8.9; (d) exposing and mixing the ferrous fuel suspension medium with the air to obtain a combustible medium within the burner apparatus having an overall oxygen to fuel equivalence ratio of 1.0 to 2.5, more preferably 1.2 to 1.8; (e) igniting the combustible medium to provide a burning iron fuel containing medium.

[0013] The present disclosure relates to a burner process for burning ferrous fuels. The inventors have found that known burner processes suitable for burning, for example, coal, coal-like materials, waste materials and biomass are not suitable or are poorly suited for burning ferrous fuels. For burning ferrous fuels, certain process design requirements that are different from these known burner processes are applicable.

[0014] Burning iron fuel has different chemical and physical properties when compared to conventional fuels. Another difference is that iron fuel is intended to be used as a combustible clean energy medium that can use iron powder in a cyclical manner, which means that the waste products of iron fuel after burning, i.e. rust or iron oxide powder, will be collected and should be suitable to be returned to iron powder. As mentioned above, the properties of iron fuel are significantly different from other fuel types such as diesel, coal, or coal-like materials. Therefore, the parameters of conventional combustion processes are not sufficient and cannot meet the requirements of such burner processes in terms of i) fuel supply, ii) stable continuous combustion, iii) general performance of the iron fuel combustion equipment, and iv) the purpose of reusing the residual iron oxide powder.

[0015] Iron powder has many advantages, among them being that it is cheap, abundant, easy to transport, and has a high energy density. In addition, it has few storage and transportation requirements, whereas other high energy density fuels, such as hydrogen, require extreme compression and / or refrigeration for efficient transportation and storage. Iron fuels also have little tendency to lose energy during long-term storage.

[0016] One of the challenges of using iron powder as a sustainable, circular energy carrier lies in the combustion process, as known burner processes are simply not suitable and / or efficient for iron fuel applications.

[0017] For an iron combustion process to be considered successful, it is not just a requirement to recover the rust in order to turn it back into iron powder; the conversion of iron to iron oxide must also be maximized for the process to be considered sufficiently efficient.

[0018] What the inventors have found is that these requirements can be met by a burner process in which the oxygen to fuel ratio is controlled, particularly at specific locations within the burner apparatus. At the time of introduction into the burner apparatus, the ferrous fuel should be in suspension, i.e. the iron is in a ferrous fuel suspension medium comprising ferrous fuel, i.e. iron powder and oxygen (preferably in a medium containing oxygen, and optionally other gases), at a concentration of 2-15 kg / Nm. 3 , more preferably 4 to 8 kg / Nm 3 It should be provided with a solid phase density of 0.1 to 0.5%. The ferrous fuel suspension medium is preferably transported uniformly distributed over the entire cross section of the pipe or duct, meaning that the suspension is transported uniformly. Those skilled in the art will recognize that a perfectly uniform distribution of the ferrous fuel powder is ideal, but in practice deviations from this will occur to a limited extent, depending inter alia on the path of the medium to / from the burner apparatus.

[0019] According to the present disclosure, uniform distribution or uniform transport should be interpreted as one or more uniform distributions of the iron fuel (particles) within the suspension medium, e.g., a uniform distribution with respect to particle size present in the iron fuel particle size distribution, and most preferably, a uniform distribution with respect to both particle mass and particle size within the medium.

[0020] When the suspending medium is introduced into the burner arrangement, it is subjected to a certain impulse which promotes the dispersion of the powder within the divergent burner shape and allows for proper mixing of the suspending medium with the additional air from the air inlet means. The air inlet means thus provides a supply of additional air to the burner arrangement in addition to the air already contained in the suspending medium prior to its introduction into the moving burner arrangement for the purpose of providing oxygen for combustion.

[0021] The air inlet means introduces air into the burner arrangement where it is mixed with the suspending medium. The burner arrangement may comprise one or more air inlet means which may be arranged in parallel, in series or in any other applicable configuration. This reduces the solid phase density of the suspending medium towards the required oxygen-fuel equivalence ratio. After obtaining said ratio, preferably by mixing in a uniformly distributed manner throughout the burner, the medium is suitable for combustion, which defines it as a combustible medium. Thus, in the final step of the process, it is possible to ignite the combustible medium. in , a stable and efficient combustion process is obtained.

[0022] In the context of this specification, ignition should be understood as the self-ignition of the medium under appropriate conditions, such as oxygen to fuel ratio, iron fuel solids density, mixture temperature, velocity, etc., but ignition may also be understood as an active step of direct ignition of the medium via an ignition means, or indirect ignition, such as a pre-heating means that raises the temperature of the medium to such an extent that it ignites. Ignition may also be interpreted as both pre-heating the medium by an ignition means and actively igniting it.

[0023] By mixing the suspension medium with an oxygen-containing gas to increase the oxygen level in the medium to the aforementioned ratio, the iron particle concentration is reduced throughout the cross section of the burner, and therefore the suspension density is reduced. However, mixing the suspension medium with excess oxygen increases the oxygen level to a level that may cause the iron fuel to burn too quickly and / or too hot, resulting in peak temperatures being reached, which may produce undesirable nanoparticles that are difficult to separate and return to the iron fuel, and further creates emission problems due to non-recoverable particles. To achieve the desired oxygen-to-fuel ratio and suspension density, the medium is exposed to air from the air inlet means according to a specific angular momentum ratio of 3 to 12, more preferably 3.8 to 8.9. The overall angular momentum ratio becomes more critical and higher compared to conventional burner processes, due among other things to the density and calorific value of the iron fuel, which in turn determines the density and required velocity of the suspension medium. This results in a sufficient degree of mixing and a defined oxygen-to-fuel ratio. The inventors have found that subjecting the suspension medium to high impulses can result in particle slagging, agglomeration and attrition, which is undesirable because it negatively impacts the burner process and the separation of rust particles (and further conversion to iron fuel), and results in mass loss due to adhesion to the burner walls, which negatively impacts the operability of the burner and also the amount of iron oxide mass available for iron oxide recycling. If the impulse is too low, i.e., with a lower angular momentum than defined above, optimal mixing is not obtained, which negatively impacts flame stability, combustion completeness and the formation of nanoparticles in thermal hot spots. Compared to conventional burners, where flame stability is primarily dictated by the geometry, the combustion process of iron fuel requires more than a specific geometry, due, among other things, to the density of the suspension medium, the velocity of the suspension medium and the mass flow rate of the particles.

[0024] As an example above, a 1 MW burner may have an iron fuel flow of about 500 kg / h. With a suspension density of 6 kg / Nm3 and a suspension velocity of 40 m / s, a suspension inlet of about 27.2 mm diameter is required. In this case, the area-weighted average radius of this inlet is 9.62 mm. If six air inlets are used to introduce air, then for two successive steps of three equal-sized inlets at a velocity of 40 m / s with an air-to-fuel equivalence ratio of 1.2, the diameter of the air inlet will be 35.8 mm. If a constant axial velocity is maintained within the burner arrangement, the cross-sectional diameters of the burner arrangement at the first and second injection stages are 67.7 and 91.8 mm, respectively. The radial distance from the center of the suspension flow to the average of the centers of the air inlets is therefore about 39.9 mm. When angles α and θ are both 90°, the angular momentum of the suspension flow and the air flow are equal to 6.52E-2 and 4.98E-1 kg*m^2 / s, respectively, resulting in an overall angular momentum ratio of about 7.64. It is expressed that this example is merely one example of a burner process according to the present disclosure, and that other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention.

[0025] In one example, the temperature of at least a portion of the combustible medium obtained in step (e) has a minimum temperature equal to the ignition temperature of the iron fuel.

[0026] When the combustible medium is at a temperature equal to the ignition temperature of the iron fuel, flame stability is achieved over a longer period of time rather than just at or immediately after ignition.

[0027] In one example, the temperature of the iron fuel suspension medium in step (b) is at least approximately equal to the ambient air temperature of the burner apparatus, and more preferably is between the ambient air temperature of the burner apparatus and a maximum temperature lower than the ignition temperature of the iron fuel. Ambient air temperature also means outside air temperature.

[0028] In one example, in steps (c) and (d), the process further comprises heating said at least a portion of said combustible medium with a heating means for heating said at least a portion of said combustible medium to a temperature of at least an ignition temperature of an iron fuel.

[0029] In one example, the air in the air inlet means is supplied at a temperature between 0 and 400°C.

[0030] In one example, the air of the air inlet means is supplied at a temperature at least approximately equal to the ambient air temperature of the burner arrangement, more preferably at a temperature between the ambient air temperature of the burner arrangement and 400°C.

[0031] To improve combustion and generate a stable and controllable flame, the iron fuel suspension medium may be introduced at an elevated temperature, for example by heating the suspension medium, more preferably by heating the suspension medium before introduction to the burner, or by heating the air in the air inlet means, preferably by heating the air before introduction to the burner. To achieve this, one or more of the following heating means may be provided: recirculation of hot steam gas, heating within the external heat of other external processes, or indirect heating from the steam gas via heat exchange means. The temperature within the burner may also be increased by heating via the heating means, recirculation, pilot flame, hot spiral, or one of several types of electrical heating means.

[0032] In one example, the air inlet means is positioned to direct the air from the air inlet means into the iron fuel burner apparatus tangentially and / or at an angle to the iron fuel suspension medium.

[0033] In one example, a vortex of the iron fuel suspension medium is created.

[0034] In one example, the air inlet means is configured to direct the air from the air inlet means coaxially with respect to the iron fuel suspension medium and into the iron fuel burner apparatus.

[0035] In one example, the ferrous fuel suspension medium has ferrous fuel particles uniformly distributed throughout the medium.

[0036] In one example, the iron fuel particles in the iron fuel suspension medium are uniform with respect to their particle size.

[0037] The impulse is achieved by introducing air through air inlet means. These direct the air either tangentially, at an angle, or coaxially to the inlet of the suspension medium. These inlet ports of the air inlet means may be arranged tangentially in the peripheral wall of the burner apparatus, and may have two, three, four, five or more air inlet ports. The air inlet ports of the air inlet means may be arranged tangentially or coaxially in a configuration such that the (mixed) suspension medium begins to swirl, improving the mixing and uniformity of the iron fuel in the medium. This has the added effect of directing the medium away from the walls of the burner apparatus, thereby preventing or at least minimizing adhesion or deposition of particles on the walls of the burner apparatus, allowing more iron oxide to be recycled for iron fuel production.

[0038] In one example, the iron fuel suspension medium has an oxygen concentration of 6 to 22 vol%.

[0039] In one example, the air from the air inlet has an oxygen concentration of 6 to 22 vol %.

[0040] An oxygen concentration of about 6-22 vol% in the air from the air inlet means will result in a stable and efficient combustion process, and that concentration may be applicable not only to the suspension medium upon introduction to the burner apparatus, but also to the air in the air inlet means.

[0041] In one example, the iron fuel burner apparatus has a diverging shape to promote the spreading of the radially outward flow of the iron fuel suspension media with the air from the air inlet means.

[0042] In one example, the iron fuel suspension media is introduced into the iron fuel burner apparatus at an angle and / or in a swirl.

[0043] As mentioned above, burning iron fuels can tend to clog the burner apparatus and corresponding parts of the iron fuel combustion system. If the suspended medium forms a swirl pattern, it can not only improve the combustion characteristics and air mixing, but also prevent or reduce deposition on the walls of the burner apparatus if the swirl is not too strong. To further benefit from these effects, the suspended medium may be introduced into the burner apparatus in such a way as to enhance this swirl effect by being introduced at an angle or in a swirling manner.

[0044] The present invention will now be described in more detail by way of specific embodiments with reference to the accompanying drawings, in which identical or similar parts and / or components are designated with the same reference numerals, and the present invention is in no way limited to the embodiments disclosed herein. [Brief description of the drawings]

[0045] [Figure 1] 1 illustrates exemplary steps of a process for burning an iron fuel according to one aspect of the present disclosure. [Diagram 2] 1 shows a schematic diagram of the media flows taken into account in the calculation of the overall angular momentum ratio. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] The invention will become apparent from the detailed description below.

[0047] In FIG. 1, four basic and minimum steps are shown in an exemplary method of a burner process for iron fuel combustion. Combusting - or burning - iron fuel is different from burning conventional fuels. Known combustion processes suitable for burning coal, coal-like materials, biomass, and waste, for example, are not suitable or are poorly suited for burning iron fuel. Burning iron fuel requires specific process design concepts that are different from these known burner processes. Conventional burner processes are not sufficient due to the different chemical and physical properties of iron fuel compared to conventional fuels.

[0048] Iron, like other metals, can be burned to produce heat. Iron powder used for such purposes has a particular preferred particle size or grain size, which may be in the range of 1 to 250 micrometers, more preferably 20 to 150 micrometers.

[0049] The ferrous fuel is burned in an oxygen-containing gas, such as air, to convert the ferrous fuel into heat, which may then be further used in a boiler or other means, preferably to transport the heat to a desired location, or to convert it into rotational energy, for example to generate electricity.

[0050] Combustion of iron fuel is a very specialized process, particularly due to the difficulties in flame stability, which requires other means than the known burner processes for conventional fuels. In addition, it is difficult to recover the iron oxide or rust to a degree suitable for regeneration into iron powder that can be used again as iron fuel. A burner process that meets these requirements, thereby allowing efficient recovery of the rust while having efficient heat transfer, is believed to be even more difficult.

[0051] A burner process for iron fuel combustion that meets these requirements and overcomes such challenges is shown in Figure 1. The burner process consists of several steps, at least the following steps:

[0052] In the first step A, a ferrous fuel suspension medium is provided. The medium may contain several components, but at least includes ferrous fuel (iron powder) and oxygen, and may be entirely oxygen-based, but more likely includes oxygen and other components. The ferrous fuel and oxygen are present at a concentration of 2-15 kg / Nm 3 , preferably 4 to 8 kg / Nm 3 The suspension is provided at a suspended solids density of 0.1 to 100 g / ml.

[0053] The iron fuel suspension medium having such properties is then introduced into the iron fuel burner apparatus in a next step B. The velocity at which the suspension medium is introduced is at least above 5.5m / s to ensure that the particles remain suspended in the air flow and no more than 55m / s as this would create further difficulties with regard to flame stability, particularly with regard to mixing of the air by the air inlet means.

[0054] The ferrous fuel suspension medium does not yet meet the requirements to be considered sufficient for the combustion of the fuel. Therefore, the suspension medium is exposed to an air flow in step C. The flow is provided by an air inlet means, which may consist of one means or several means, and may comprise one or several (preferably evenly distributed) air inlet ports that introduce air into the burner device. The air flow mixes with the ferrous fuel suspension medium to obtain a medium that meets the combustion requirements and is therefore defined as a combustible medium. The mixing is a result of the air inlet means introducing the air and directing it with a certain impulse into the suspension medium to generate angular momentum in the flow. The dimensionless overall angular momentum ratio (I ratio ) is calculated using: TIFF2025509984000002.tif28170 · Here, I x is I=ρ v 2 The angular momentum is defined as G=ρ·v 2 Note that the momentum of the impulse G defined by the inlet and the surface area is defined as J=ρ·v 2 is defined as follows: ρ air is the air density at the inlet (kg / m 3 ). ρ susp is the suspension density (kg / m) at the suspension inlet 3 ) and does not include the mass flow of air in the suspension mixture. ·v air is the air injection speed (m / s). ·v susp is the velocity of suspension injection in m / s. A air is the surface area of ​​the air inlet (m 2 ). A susp m 2 is the surface area of ​​the unit suspension inlet. ·r susp is the area-weighted average radius of the suspension flow in meters (assuming the cross section of the flow is uniformly distributed). ·r air is the radial distance from the center of the suspension (also center of flow) to the average of the centers of the air inlets in meters (but does not exclude non-averages). α and θ are the angles between the suspension flow and the air inlet means as shown diagrammatically in FIG.

[0055] The dimensionless total angular momentum ratio (I ratio A burner process according to the present disclosure having a burner pressure of 1000 MPa may also be defined by: TIFF2025509984000003.tif28170TIFF2025509984000004.tif28170Impulse [kg*m*s^-1] can be defined by the following: TIFF2025509984000005.tif17170TIFF2025509984000006.tif17170Angular momentum [kg*m^2* *s^-1] can be defined by the following: TIFF2025509984000007.tif17170TIFF2025509984000008.tif17170TIFF2025509984000009.tif17170Also, momentum flux can be defined by: TIFF2025509984000010.tif17170

[0056] The overall angular momentum ratio is between 3 and 12 to ensure sufficient radial outward movement of the suspension (producing angle β in FIG. 2) but also to prevent the suspension flow from moving so radially outward that excessive wear of the burner components occurs. Preferably, the ratio is between 3.8 and 8.9. An upper limit introduces risk of particle wear and potential agglomeration and stalagmite / stalactite formation in the burner apparatus and downstream components.

[0057] Once the suspension medium is mixed and a combustible medium is obtained, the medium can be ignited, thus generating heat and leaving as a residue a medium containing iron oxide from which the iron oxide can be separated, recovered and regenerated into iron fuel.

[0058] The following data represents several cases of suspension and air conditions as experimental data for the present invention and the disclosed embodiments. This example and its cases demonstrate that, at least for case 5, the lambda value λ or air-fuel ratio is achieved at the preferred ratios of 1.2 and 1.8. Cases 4 and 5 also show lambda values ​​slightly beyond the preferred ratio bandwidth, but where the claimed effect is achieved. TIFF2025509984000011.tif95170

[0059] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The scope of the invention is defined by the appended claims. One or more of the objects of the invention are achieved by the appended claims.

Claims

1. 1. A burner process for burning iron fuel, comprising: (a) 2-15kg / Nm ３ , more preferably 4 to 8 kg / Nm ３ providing an iron fuel suspension medium comprising iron fuel and oxygen at a suspended solids density of (b) introducing the iron fuel suspension medium into an iron fuel burner apparatus at a velocity of from 5.5 to 55 m / s, more preferably from 20 to 40 m / s; (c) introducing air into the iron fuel burner apparatus through an air inlet means, the air from the air inlet means being introduced with an overall angular momentum ratio between the air and the iron fuel suspension medium of between 3 and 12, more preferably between 3.8 and 8.9; (d) exposing and mixing said iron fuel suspension medium with said air to obtain a combustible medium within said burner apparatus to obtain an overall oxygen to fuel equivalence ratio of 1.0 to 2.5, more preferably 1.2 to 1.8; (e) igniting the combustible medium to provide a burning iron fuel containing medium; The burner process includes:

2. 2. The burner process for burning iron fuel as set forth in claim 1, wherein the temperature of at least a portion of the combustible medium obtained in step (e) has a minimum temperature equal to an ignition temperature of the iron fuel.

3. 3. A burner process for burning iron fuel as set forth in claim 2, wherein the temperature of the iron fuel suspension medium in step (b) is at least approximately equal to the ambient air temperature of the burner apparatus, and more preferably has a temperature between the ambient air temperature of the burner apparatus and a maximum temperature lower than the ignition temperature of the iron fuel.

4. 4. The burner process for burning iron fuel as claimed in claim 2 or 3, wherein in steps (c), (d) and (e), the process further comprises heating with heating means for heating at least a portion of the combustible medium to a minimum temperature at least equal to the ignition temperature of the iron fuel.

5. 5. A burner process for burning iron fuel as claimed in any one of claims 2 to 4, wherein the air of the air inlet means is supplied at a temperature at least approximately equal to the ambient air temperature of the burner arrangement, more preferably between the ambient air temperature of the burner arrangement and 400°C.

6. 6. A burner process for burning iron fuel as claimed in any one of claims 1 to 5, wherein the air inlet means is configured to direct the air from the air inlet means into the iron fuel burner apparatus tangentially and / or at an angle to the iron fuel suspension medium.

7. 7. A burner process for burning iron fuel as claimed in any one of claims 1 to 6, wherein the iron fuel suspension medium is introduced into the iron fuel burner apparatus at an angle and / or in a swirling manner.

8. 8. A burner process for burning iron fuel as claimed in any preceding claim, wherein the air inlet means is configured to direct the air into the iron fuel burner apparatus coaxially and / or at an angle to the iron fuel suspension medium.

9. 9. A burner process for burning iron fuel as claimed in any one of claims 1 to 8, wherein the iron fuel suspension medium is uniformly distributed across the cross section of the iron fuel particles in the medium.

10. 10. A burner process for burning iron fuel as claimed in any one of claims 1 to 9, wherein the iron fuel particles in the iron fuel suspension medium are uniformly distributed in the cross section in terms of their particle size.

11. A burner process for burning iron fuel as claimed in any one of claims 1 to 10, wherein the iron fuel suspension medium has an oxygen concentration of 6 to 22 vol%.

12. 11. A burner process for burning iron fuel as claimed in any one of claims 1 to 10, wherein the iron fuel suspension medium has an enriched oxygen concentration at least greater than the ambient oxygen concentration for promoting iron fuel ignition.

13. A burner process for burning iron fuel as claimed in any one of claims 1 to 12, wherein the air from the air inlet has an oxygen concentration of 6 to 22 vol%.

14. 14. A burner process for burning iron fuel as claimed in any one of claims 1 to 13, wherein the iron fuel burner apparatus has a diverging geometry to provide a substantially constant average axial velocity while rated loading of the flow in the cross-section over the length of the burner apparatus is achieved in steps (c) and / or (d).

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