Method for injecting hot gas into a blast furnace and installation thereof

Abstract

The invention relates to a method for injecting hot gas into a blast furnace, wherein said method comprises the following steps: - introducing gas into at least one device for heating gas, said device for heating gas comprising: o a pipe allowing gas to flow inside of it, o an insert located inside said pipe, said insert being electrically conductive, o an inductor located in the vicinity of said pipe, - feeding energy into said insert using said inductor of said device for heating gas so that said energy fed into the insert is transferred to the gas introduced into said device for heating gas, to heat said gas to a temperature from 700°C to 2300°C, - releasing said hot gas into the blast furnace using means for releasing gas, said means for releasing gas being connected to said at least one device for heating gas.

Description

[0001] Method for injecting hot gas into a blast furnace and installation thereof

[0002]

[0001] The present invention relates to a method for injecting hot gas into a blast furnace and a blast furnace installation. More precisely, the present invention relates to a method for injecting hot gas into a blast furnace using induction heating.

[0003]

[0002] In the process of making steel using a blast furnace, gas needs to be injecting into the blast furnace at temperatures around 1000°C. For this, it needs to be heated beforehand. In classical facilities, the heating of gas is usually done using fuel combustion. Hot stoves, for example, are regenerative heaters that uses fuel combustion where the heater shifts alternatively from an oxidizing phase to a reducing phase to heat a reducing gas.

[0004]

[0003] However, fuel combustion causes CO2 emissions and as CO2 emissions need to be reduced in the steel industry, there is a need for an alternative method for heating gas that allows CO2 emissions to be reduced or even suppressed.

[0005]

[0004] It is known from Chinese patent application CN113566044 that a gas can be heated to a temperature of around 1000°C with an electrical method, more precisely, using induction heating. The patent application describes a method for continuously heating a chlorine gas to a temperature of 700 to 1600°C consisting in heating a graphite pipeline using an induction heater and make the chlorine gas flow into the hot pipe.

[0006]

[0005] This method allows the heating of gas without the use of combustion thus reducing CO2 emissions of the process. However, for the usual flow rates of gas needed in blast furnaces, the implementation of this method is difficult as it would require a massive installation to reach similar temperatures.

[0006] The aim of the present invention is therefore to remedy the drawbacks of the prior art by providing a method for injecting hot gas into a blast furnace within a limited space while reducing CO2 emissions.

[0007]

[0007] For this purpose, a first object of the present invention consists in a method for injecting hot gas into a blast furnace, wherein said method comprises the following steps:

[0008] - introducing gas into at least one device for heating gas, said device for heating gas comprising: o a pipe allowing gas to flow inside of it, o an insert located inside said pipe, said insert being electrically conductive, o an inductor located in the vicinity of said pipe,

[0009] - feeding energy into said insert using said inductor of said device for heating gas so that said energy fed into the insert is transferred to the gas introduced into said device for heating gas, to heat said gas to a temperature from 700°C to 2300°C,

[0010] - releasing said hot gas into the blast furnace using means for releasing gas, said means for releasing gas being connected to said at least one device for heating gas.

[0011]

[0008] The method for injecting hot gas into a blast furnace according to the invention may also have the optional features listed below, considered individually or in combination:

[0012] - the gas is heated to a temperature from 700°C to 1500°C,

[0013] - the flow of gas inside the pipe of the device for heating gas has a Reynolds number superior to 2800,

[0014] - the means for releasing gas is at least one shaft injector,

[0015] - each of the shaft injectors is connected to a single device for heating gas, said device for heating gas being located just ahead of said shaft injector, - the method comprises an additional step consisting of releasing hot gas into the blast furnace using tuyeres, said tuyeres being connected to said at least one device for heating gas,

[0016] - each of the tuyeres is connected to a single device for heating gas, said device for heating gas being located just ahead of said tuyere,

[0017] - the heated gas is composed of one or more of the following gases: syngas, CO2, CO, H2, H2O, hydrocarbons, N2.

[0018]

[0009] A second object of the invention consists in a blast furnace installation, wherein said blast furnace comprises:

[0019] - at least one device for heating gas, said device for heating gas comprising: o means for injecting gas into said device for heating gas, o a pipe allowing the gas injected to flow inside of it, o an insert located inside said pipe, said insert being electrically conductive, o an inductor located in the vicinity of said pipe and able to feed energy into said insert, so that said energy fed into said insert is transferred to the gas flowing into said pipe, wherein said device for heating gas has a power from 1 kW to 50MW,

[0020] - means for releasing hot gas into the blast furnace, said means for releasing gas being connected to said at least one device for heating gas.

[0021]

[0010] The blast furnace installation according to the invention may also have the optional features listed below, considered individually or in combination:

[0022] - the means for releasing gas into the blast furnace are shaft injectors and / or tuyeres,

[0023] - the insert is designed to have an exchange surface with the gas to be heated that ranges from 0.5m2to 100m2by meter of pipe,

[0024] - the insert is made of one of the following materials: magnetic steel, graphite, tungsten, molybdenum,

[0025] - the inductor is a coil.

[0011] Other characteristics and advantages of the invention will be described in greater detail in the following description.

[0026]

[0012] The invention will be better understood by reading the following description, which is provided purely for purposes of explanation and is in no way intended to be restrictive, with reference to:

[0027]

[0013] Figure 1 , which is a general view of the device for heating gas according to one embodiment of the invention,

[0028]

[0014] Figure 2, which is a cross-sectional view of the interior of the pipe of the device for heating gas according to one embodiment of the invention,

[0029]

[0015] Figures 3a and 3b, which are representations of embodiments of the insert of the device for heating gas according to the invention,

[0030]

[0016] Figure 4, which represents a blast furnace,

[0031]

[0017] Figures 5a, 5b, 5c, 5d, 5e, 5f and 5g, which are representations of embodiments of the invention,

[0032]

[0018] Figure 6, which is a comparative graph representing the heating of a gas with a device for heating gas according to the prior art and a device for heating gas according to the invention.

[0033]

[0019] The blast furnace 5, represented in Fig 4, comprises, starting from the top, a throat 9 wherein materials are loaded and gas exhaust, a stack - or shaft - 10, a belly 11 , a bosh 12 and a hearth 13. The materials loaded are mainly iron-bearing materials such as sinter, pellets or iron ore and carbon- bearing materials such as coke. The hot blast injection necessary to carbon combustion and thus iron reduction is performed by tuyeres 7 located near the bosh 12 and the hearth 13. In terms of structure, the blast furnace 5 has an external wall, or shell, this shell being covered, on the inside of the blast furnace 5, by a refractory lining and staves, forming an internal wall. The blast furnace 5 has an internal diameter Dint which varies from the top to the bottom. To reduce consumption of coke, which is the main carbon provider for iron reduction, it has been envisaged to inject a reducing gas into the blast furnace 5 in addition to the hot blast. This reducing gas injection is performed in the shaft 10 of the blast furnace 5 by shaft injectors 6, preferentially in the lower part of the shaft 10.

[0034]

[0020] With reference to Figures 1 and 2, the method for injecting hot gas into a blast furnace 5 according to the invention and the blast furnace installation according to the invention will be described in detail.

[0035]

[0021] The method for injecting hot gas into a blast furnace 5 according to the invention comprises first the step of introducing gas into at least one device for heating gas 1 . The device for heating gas 1 first comprises a pipe 2 that allows the gas to be heated to flow inside of it. The device for heating gas 1 also comprises an insert 3 located inside the pipe 2 and that is electrically conductive as well as an inductor 4 located in the vicinity of the pipe 2. The second step consists in feeding energy to the insert 3. To achieve this, the inductor 4 creates a magnetic field that induces a current in the insert 3. This energy fed to the insert 3 results in the heating of the insert 3. This energy is then transferred from the hot insert 3 to the gas flowing into the pipe 2 that is thus heated to a temperature from 700°C to 2300°C. The third step consists in releasing the heated gas into the blast furnace 5 using means for releasing gas. The means for releasing gas are connected to the exit of at least one device for heating gas 1 .

[0036]

[0022] A first embodiment of the invention is represented in Fig 5a. In this embodiment, the means for releasing gas are shaft injectors 6. In this embodiment, the total flow rate of the gas injected into the blast furnace 5 is heated thanks to a single device for heating gas 1 . The total flow rate of the hot gas is retrieved in a feeding pipe 8, at the exit of the device for heating gas 1 , that is then divided into a plurality of smaller pipes to distribute the total flow rate of the gas into all of the shaft injectors 6 that inject the hot gas into the shaft 10.

[0037]

[0023] A second embodiment of the invention is represented in Fig 5b. In this embodiment, the total flow rate is divided into several devices for heating gas 1 that each will heat only a part of the total flow rate. The hot gas is then distributed into all of the shaft injectors 6, like in the first embodiment. In this embodiment, half of the shaft injectors 6 are connected to a single device for heating gas 1. This embodiment allows an easier implementation of the invention when high flow rates of gas are needed as it allows to have smaller devices that each requires less energy.

[0038]

[0024] A third embodiment of the invention is represented in Fig 5c. In this embodiment, the means for releasing gas are shaft injectors 6. In this embodiment, each of the shaft injectors 6 is linked to a single device for heating gas 1 that is located just ahead of the shaft injector 6. The total flow rate of gas is thus divided by the number of shaft injectors 6 of the blast furnace installation. This embodiment allows the gas to remain cold until just before the injection, thus facilitating the control and automation of the gas distribution. It also allows to have a multitude of small devices for heating gas that are thus easier to implement.

[0039]

[0025] Fig 5d, 5e, 5f and 5g represents other embodiments of the invention with an additional step consisting of releasing hot gas into the blast furnace 5 using tuyeres 7. The tuyeres 7 are connected to at least one device for heating gas 1 . This additional step allows to reduce the amount of carbon that must be burnt at the tuyeres 7 to satisfy the heat requirement of the elaboration zone of the blast furnace 5, thus reducing the global CO2 consumption of the process.

[0040]

[0026] In Fig 5d, only one device for heating gas 1 heats the total flow rate of the gas to be injected in the blast furnace 5, like in the first embodiment, and the hot gas is distributed to all of the shaft injectors 6 and the tuyeres 7. In Fig 5e, a device for heating gas 1 heats the gas for the tuyeres 7 separately from the gas for the shaft injectors 6. In Fig 5f, the total flow rate is divided into several devices for heating gas 1 , like the second embodiment, and the hot gas is then distributed to all of the shaft injectors 6 and the tuyeres 7. In Fig 5g, each of the shaft injectors 6 and the tuyeres 7 is linked to a single device for heating gas 1 that is located just ahead of each means for injecting gas, similar to the configuration of the third embodiment.

[0041]

[0027] Alternative embodiments using only tuyeres 7 as means for releasing gas into the blast furnace 5 can be considered. Alternative embodiments consisting of combinations of the preceding embodiments can also be considered. The invention is not limited to the embodiments represented in Fig 5 and other configurations can be considered.

[0042]

[0028] The insert 3 is a piece that is located inside the pipe 2. Its purpose is to transfer energy to the gas flowing into the pipe 2. This transfer occurs as the gas flows into the pipe 2 and enters in contact with the exchange surface of the insert 3. The gas is thus heated by forced convection and / or radiation.

[0043]

[0029] For the structure of the insert 3, increasing the exchange surface will improve the efficiency of the heating as the insert 3 can transfer more energy to the gas over the length of the pipe 2. The exchange surface corresponds to the surface of the insert 3 that the gas can enter in contact with. The higher the surface exchange of the insert 3 is, the shorter the pipe 2 length required to reach a given target temperature is as well.

[0044]

[0030] For each meter of length of pipe, the insert 3 preferably has an exchange surface from 0.5 m2to 100 m2For an exchange surface below 0.5 m2for each meter of length of pipe 2, the efficiency of the heating can be insufficient to reach the target temperature. For an exchange surface above 100 m2for each meter of pipe 2, the gas could reach the target temperature way before the end of the pipe 2 thus reducing the efficiency of the heating compared to the material used. More preferably, for each meter of length of pipe 2, the insert 3 has an exchange surface from 0.5 m2to 80 m2or from 0.5 m2to 60 m2or from 0.5 m2to 50 m2or from 0.5 m2to 40 m2or from 0.5 m2to 30 m2or from 0.5 to 25 m2or from 0.5 m2to 20 m2or from 0.5 m2to 15 m2or from 0.5 m2to 10 m2or from 0.5 m2to 7.5 m2or from 0.5 m2to 5 m2or from 0.5 to 2.5 m2or from 1 m2to 100 m2or from 1 m2to 80 m2or from 1 m2to 60 m2or from 1 m2to 50 m2or from 1 m2to 40 m2or from 1 m2to 30 m2or from 1 to 25 m2or from 1 m2to 20 m2or from 1 m2to 15 m2or from 1 m2to 10 m2or from 1 m2to 7.5 m2or from 1 m2to 5 m2or from 1 m2to 2.5 m2

[0045]

[0031] The efficiency of the heating can also be improved by imposing an agitation to the gas flow inside the pipe 2. This is provided by creating a turbulent flow inside the pipe 2.

[0032] The flow patterns are usually characterized by the Reynolds number (Re). Usually, the Reynolds number is defined as: puL Re = - —

[0046] A p: density of the fluid (kg / m3) u: flow speed (m / s)

[0047] L: characteristic length (m) p: dynamic viscosity (kg / (m.s)) A turbulent flow is characterized by a Reynolds number Re > 2800.

[0048]

[0033] The shape of the insert 3 has an influence on the Reynolds number as it modifies the characteristic length L of the system. A shape designed to provide turbulent flow to the gas flowing into the pipe 1 can thus improve the efficiency of the heating of the gas.

[0049]

[0034] To further improve the efficiency, the insert 3 preferably extends from the entrance of the pipe 2 to the exit of the pipe 2. The insert 3 also preferably has a section that represents from 50% to 100% of the free section inside the pipe 2, that is to say, the section where the gas is flowing. Having an insert with a section that is almost the same as the free section of the pipe allows to avoid that a large fraction of the gas flows around the insert 3 without being heated by the insert 3. However, having a smaller section allows the insert 3 to expand more freely with thermal dilatation without damaging the device for heating gas 1 . An insert 3 with a section of 100% of the free section of the pipe 2 can be considered with a material such as Invar™ that has a thermal expansion rate sufficiently low so as not to damage the pipe 2. With a section lower than 50% of the free section of the pipe 2, the efficiency of the heating could be too low. More preferably, the section of the insert 3 comparatively to the free section of the pipe 2 is from 50% to 97.5% or from 50% to 95% or from 50% to 92.5% or from 50 to 90% or from 50% to 85% or from 50% to 80% or from 50% to 75% or from 60% to 97.5% or from 60% to 95% or from 60% to 92.5% or from 60 to 90% or from 60% to 85% or from 60% to 80% or from 60% to 75% or from 65% to 97.5% or from 65% to 95% or from 65% to 92.5% or from 65 to 90% or from 65% to 85% or from 65% to 80% or from 65% to 75% or from 70% to 97.5% or from 70% to 95% or from 70% to 92.5% or from 70 to 90% or from 70% to 85% or from 70% to 80% or from 70% to 75%.

[0050]

[0035] Examples for insert designs are represented in Fig 3a and Fig 3b. The insert represented in Fig 3a has a screw shape and the insert represented in Fig 3b has a perforated twisted tape shape. These designs provide a high exchange surface comparatively to the length of the pipe 2 and can also provide a turbulent flow for typical gas speeds injected in a blast furnace 5.

[0051]

[0036] The designs of the insert 3 are not limited to the ones represented in Fig 3a and Fig 3b and other designs can be considered.

[0052]

[0037] In order to be heated, the insert 3 has to be made of a material that is electrically conductive. The insert 3 is preferably made of magnetic steel or graphite but can also be made of any electrically conductive material. An electrically conductive material is any material that has an electrical conductivity value o > 10 000 (Q.m)-1.

[0053]

[0038] Magnetic steel can be used as a material for the insert 3 for heating non oxidizing gas to temperatures up to 1000°C, preferably up to 1200°C without material degradation. For higher temperatures, it is preferable to use graphite as a material for the insert 3 as graphite can reach temperatures higher than 3000°C. Tungsten and molybdenum can also be considered as material for the insert 3 for high temperatures as they can resist to temperatures higher than 3000°C. For heating oxidizing gases, stainless steel can be used as the induced material.

[0054]

[0039] The insert can be manufactured using additive manufacturing.

[0055]

[0040] The inductor 4 is preferably a coil and is located in the vicinity of the pipe 2. Preferably, the inductor 4 is located inside the pipe 2 close to its wall as represented in Fig 2. This configuration allows to avoid heating the pipe 2 alongside the insert 3 if the pipe is made of a material that is also electrically conductive. In this configuration, a refractory material is placed between the insert and the inductor to serve as a thermal insulator. A magnetic yoke is also preferably installed inside the pipe 2, between the inductor 4 and the wall of the pipe 2. It can be a plate of electric steel. Its purpose is to confine the magnetic field inside the pipe 2 so as not to heat the pipe 2 to increase the energy efficiency. Alternatively, the inductor 4 can be placed outside the pipe 2, as in Fig 1 , if the pipe 2 is made of a material that is not electrically conductive.

[0056]

[0041] A various number of gases can be heated using the method according to the invention. The following Table 1 gives a list of gases that can be heated using two specific materials for the insert 3.

[0057] Table 1

[0058]

[0042] The gases that are listed in Table 1 are only listed as examples and the gases that can be heated using the invention are not limited to these gases. In the same way, the materials that are listed in Table 1 are only listed as examples and the materials that are used for the insert in the invention are not limited to these materials.

[0059]

[0043] A step of cleaning the gas is preferably done before heating to remove most of the particles that can be present. This step of cleaning can be done with a specific equipment using venturi effect and scrubbers to remove particles with water. This step can also be done by mechanical separation or any other means to remove particles from a gas. Preferably, the amount of particles in the heated gas is not more than 5mg / Nm3. Nm3stands for Normal cubic meters and is a unit of measurement of the quantity of gas which corresponds to the content of a volume of one cubic meter, for a gas under normal temperature and pressure conditions (0°C and 1 atm.). Preferably, the size of the particles present in the heated gas is not more than 50pm.

[0060]

[0044] The pipe 2 preferably has a cylindrical shape. To reach a certain power, a minimal surface and / or mass of induced material is needed in the form of the insert 3. The shape of the insert 3 and the dimensions of the pipe 2 are arranged to provide optimal efficiency and compacity of the device for heating gas 1 depending on the power needed for the application it is used for. As the pipe 2 is not heated in the device for heating gas 1 according to the invention, the thickness of the pipe 2 does not have an influence on the efficiency of the heating contrary to the prior art where the pipe 2 itself is heated.

[0061]

[0045] The gas is heated to a temperature from 700°C to 2300°C. Preferably, the gas is heated to a temperature from 700°C to 1500°C.

[0062]

[0046] The flow rates for the gas that are considered for the invention are usual flow rates of gas for the injection into a blast furnace. The person skilled in the art would know what flow rates of gas is needed for the application he wants to use the invention.

[0063]

[0047] In the applications of the method according to the invention, a given global gas flow rate of a given composition is heated to a target temperature. Depending on the value of this global gas flow rate and the target temperature, the required global heating power can range from 1 kW to 50MW. For low power values, for example in the order of 1 kW to 10kW, a single device for heating gas would be sufficient to provide this level of power, like the first embodiment of the invention. For higher power range, for example in the order of 10MW to 50MW, depending on the technology available to the person skilled in the art, a single device for heating gas 1 can be insufficient to obtain this level of power. In this case, the global gas flow rate to be heated can be divided in several streams of lower flow rate that will each be heated by a single device for heating gas 1 and require much lower power to reach the same target temperature, like the second or the third embodiment of the invention.

[0064]

[0048] Preferably, the power of the steelmaking vessel is from 1 kW to 10MW, more preferably from 1 kW to 1 MW, more preferably from 1 kW to 100kW, more preferably from 1 kW to 50kW, more preferably from 1 kW to 10kW.

[0065]

[0049] Examples of dimensioning for the device for heating gas in the installation according to the invention are given in Table 2 and Table 3 below.

[0066]

[0050] Table 2 shows four examples of a blast furnace (BF) in a usage configuration. able 2

[0067]

[0051] For each case, the hot metal produced by the BF is represented in tons of hot metal by hour (thm / h). A target gas flow rate and a target gas temperature at the shaft injectors are predefined for each case. The same is done with the tuyeres. A target gas flow rate and a target gas temperature at the tuyeres are predefined for each case. The gas heated is syngas. The unit of the flow rate is Nm3 / h with Nm3which stands for Normal cubic meters, and which is a unit of measurement of the quantity of gas which corresponds to the content of a volume of one cubic meter, for a gas under normal temperature and pressure conditions (0°C and 1 atm.).

[0068]

[0052] Table 3 represents the calculated power needed to heat the gas at the target temperature and at the target flow rate for each case.

[0069]

[0053] For each case, the total power needed at shaft injectors is calculated using thermodynamical models, such as commercial software ThermoCalc™, FastSage™ or ChemSims™ The total power needed at shaft injectors is the power that the device for heating gas should be able to provide if there is only one device for heating gas to heat the totality of the flow rate for the shaft injectors, like represented in Fig 5e. The power needed per shaft injector is the total power divided by the number of shaft injectors. It represents the power that a device for heating gas should be able to provide if there is one device for heating gas for each shaft injector, like represented in Fig 5g. For the tuyeres, the same principle is applied. The total power needed at tuyeres is calculated using thermodynamical models like for the shaft injectors. The total power needed at tuyeres is the power that the device for heating gas should be able to provide if there is only one device for heating gas to heat the totality of the flow rate for the tuyeres, like represented in Fig 5e. The power needed per tuyere is the total power divided by the number of shaft injectors. It represents the power that a device for heating gas should be able to provide if there is one device for heating gas for each shaft injector, like represented in Fig 5g.

[0070]

[0054] Fig 6 represents a comparative heating of a gas heated according to the prior art and a gas heated according to the invention. The first curve represents the heating with a device for heating gas according to the prior art. A gas flows inside the pipe and the pipe is heated using induction heating. The second curve represents the heating with the heating device according to the invention. The pipe 2 is not heated and only the insert 3 is heated.

[0071]

[0055] The curves were calculated using a simulation with Fluent, a software published by Ansys, Inc. For both curves, the conditions of heating are the same. The pipe has a diameter of 300mm, a thickness of 5mm and a length of 2m. The gas heated is H2 with a mass flow of 68kg / h. For the curve of the heating according to the invention, the inductor 4 is located outside the pipe 2, the insert 3 is of screw type, like represented in Fig 3a, with a diameter equal to the diameter of the pipe 2. The total surface of the insert is 2.66 m2and the Reynolds number is 9300.

[0072]

[0056] The comparison shows that a more efficient heating over a shorter length can be obtained with the heating device according to the invention.

[0057] The method according to the invention allows to successfully inject hot gas into the blast furnace using only a limited space while reducing the CO2 emissions of the process.

Claims

CLAIMS1 ) A method for injecting hot gas into a blast furnace (5), wherein said method comprises the following steps:- introducing gas into at least one device for heating gas (1 ), said device for heating gas (1 ) comprising: o a pipe (2) allowing gas to flow inside of it, o an insert (3) located inside said pipe, said insert (3) being electrically conductive, o an inductor (4) located in the vicinity of said pipe (1 ),- feeding energy into said insert (3) using said inductor (4) of said device for heating gas (1 ) so that said energy fed into the insert (3) is transferred to the gas introduced into said device for heating gas (1 ), to heat said gas to a temperature from 700°C to 2300°C,- releasing said hot gas into the blast furnace (5) using means for releasing gas, said means for releasing gas being connected to said at least one device for heating gas (1 ).2) A method for injecting hot gas into a blast furnace (5) according to claim 1 wherein said gas is heated to a temperature from 700°C to 1500°C.3) A method for injecting hot gas into a blast furnace (5) according to any of the preceding claims wherein the flow of gas inside the pipe of the device for heating gas has a Reynolds number superior to 2800.4) A method for injecting hot gas into a blast furnace (5) according to any of the preceding claims wherein said means for releasing gas is at least one shaft injector (6).5) A method for injecting hot gas into a blast furnace (5) according to claim 4 wherein each of said shaft injectors (6) is connected to a single device for heating gas (1 ), said device for heating gas (1 ) being located just ahead of said shaft injector (6).6) A method for injecting hot gas into a blast furnace (5) according to any of the preceding claims wherein said method comprises an additional step consisting of releasing hot gas into the blast furnace (5) using tuyeres (7), said tuyeres (7) being connected to said at least one device for heating gas (1 ).7) A method for injecting hot gas into a blast furnace (5) according to claim 6 wherein each of said tuyeres (7) is connected to a single device for heating gas (1 ), said device for heating gas (1 ) being located just ahead of said tuyere (7).8) A method for injecting hot gas into a blast furnace (5) according to any one of the preceding claims wherein said heated gas is composed of one or more of the following gases: syngas, CO2, CO, H2, H2O, hydrocarbons, N2.9) A blast furnace installation, wherein said blast furnace installation comprises:- at least one device for heating gas (1 ), said device for heating gas (1 ) comprising: o means for injecting gas into said device for heating gas (1 ), o a pipe (2) allowing the gas injected to flow inside of it, o an insert (3) located inside said pipe, said insert (3) being electrically conductive, o an inductor (4) located in the vicinity of said pipe (2) and able to feed energy into said insert (3), so that said energy fed into said insert (3) is transferred to the gas flowing into said pipe (2), wherein said device for heating gas (1 ), has a power from 1 kW to 50MW,- means for releasing hot gas into the blast furnace (5), said means for releasing gas being connected to said at least one device for heating gas10) A blast furnace installation according to claim 9, wherein said means for releasing gas into the blast furnace (5) are shaft injectors (6) and / or tuyeres (7). 11 ) A blast furnace installation according to claims 9 or 10, wherein said insert(3) is designed to have an exchange surface with the gas to be heated that ranges from 0.5m2to 100m2by meter of pipe.12) A blast furnace installation according to any of claims 9 to 11 , wherein said insert (3) is made of one of the following materials: magnetic steel, graphite, tungsten, molybdenum.13) A blast furnace installation according to any of claims 9 to 12, wherein said inductor (4) is a coil.

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