Controlling temperature and NOx content of reducing gas

Abstract

The invention relates to a method for reducing metal oxide-containing materials, in which a reducing gas containing at least hydrogen is supplied to a reduction reactor (3) and a hydrogen-containing top gas is discharged from the reduction reactor (3). A partial amount of the top gas is supplied as a component of a fuel gas to a gas burner (6) for producing a reducing gas. When the hydrogen proportion in the reducing gas and / or the top gas increases, the water vapor content in the fuel gas is increased. The device for the method comprises a reduction reactor (3); a top gas discharge line (5) for discharging the top gas from the reduction reactor (3); comprising at least one gas burner (6) for preparing a reducing gas; and a supply duct (8) for supplying a partial amount of the top gas as a component of the fuel gas to the at least one gas burner (6). Characterized in that it further comprises at least one member selected from the following two members: a) at least one means (9) for determining the water vapor content in the reducing gas and / or the top gas, and b) means (9a) for detecting an increase in the hydrogen proportion in the reducing gas and / or the top gas; and means (10) for open-loop and / or closed-loop control of the water vapor content in the fuel gas with reference to the hydrogen content in the reducing gas and / or the top gas.

Description

Technical Field

[0001] The present application relates to a method and an apparatus for reducing a material containing metal oxides, wherein a reducing gas is used. Prior art

[0002] It is well known that materials (e.g. ores) containing metal oxides (e.g. iron oxides) can be reduced by reducing gases. For example, by direct reduction with reducing gases in a reduction device (e.g. a reduction shaft). In the conventional methods currently used on a large scale in industry, the reducing gas is mainly based on carbon in natural gas (e.g. carbon monoxide CO or methane CH4). Therefore, large amounts of carbon dioxide CO2 are produced, which is undesirable, in particular for environmental policy reasons.

[0003] In order to reduce CO2 emissions during the reduction of materials containing metal oxides, it is known to use hydrogen H2 as a reducing gas. Hydrogen can be used as the only reducing gas or in combination with other gases, for example based on carbon from natural gas. The greater the proportion of hydrogen H2 in the reducing gas that is CO2-neutral with respect to the reduction reaction, the lower the CO2 emissions. Depending on the availability of natural gas and hydrogen, the ratio of their contributions to the reducing gas can be varied by mixing different amounts. The more hydrogen is available, the more it is possible to cancel the climate-damaging contribution based on carbon from natural gas.

[0004] It is advantageous to also operate existing plants and operating methods that base the reducing gas predominantly on carbon from natural gas with an increased proportion of hydrogen in the reducing gas. This enables flexible response to the availability of natural gas and hydrogen and allows the utilization of already made plant investments.

[0005] At least until sufficient amounts of hydrogen are available to use a completely hydrogen-based reducing gas, the reducing gas must still rely on carbon from natural gas.

[0006] Reducing gas is usually supplied to a reduction reactor containing a material containing metal oxides, and top gas is discharged from the reduction reactor. Top gas is formed by the reducing gas when it flows through the reduction reactor, because components of the reducing gas react with the material containing metal oxides in the reduction reactor, or with products formed in these reactions, such as formed metallic iron. Due to the reduction reaction that occurs in the reduction reactor, the reducing power of the top gas is lower than that of the reducing gas, and has a calorific value. In order to utilize the reducing power, the top gas is usually used as a component when preparing fresh reducing gas.

[0007] The reducing gas is usually heated in a gas heating device by means of a gas burner in order to obtain the temperature required for the reduction reaction. In processes in which the preparation of the reducing gas is based on the reforming of a precursor gas (e.g. natural gas), the energy for the reforming is usually provided by a gas burner. The gas burner requires a fuel gas and an oxidizing gas (e.g. air); during the combustion process, the fuel gas is oxidized, thereby releasing energy. It is known that top gas is suitable for use as fuel gas due to its calorific value.

[0008] As the proportion of hydrogen in the reducing gas increases, the proportion of hydrogen in the top gas also increases. This has the disadvantage, when used as fuel gas, that the adiabatic flame temperature increases during combustion. This increase in adiabatic flame temperature can have adverse effects:

[0009] - When air is used as the oxidizing gas, a large amount of nitrogen is present; as the adiabatic flame temperature increases, more undesirable nitrogen oxides NO are formed x However, the nitrogen may also originate from combustible nitrogen-containing gases present in the fuel gas, such as ammonia NH 3 - so-called fuel nitrogen - or from gaseous nitrogen N 2 in the fuel gas.

[0010] - For energy optimization, gases such as oxidizing gas, fuel gas and reducing gas precursors are usually heated by heat exchange with the exhaust gases of the gas burner. Heat transfer is usually by radiation. The increased adiabatic flame temperature has a negative impact on radiation-based heat transfer. Summary of the invention

[0011] Technical Purpose

[0012] The present invention aims to contribute to alleviating at least some of the above mentioned problems.

[0013] Technical Solution

[0014] This is achieved by:

[0015] A method for reducing a material containing a metal oxide,

[0016] wherein a reducing gas containing at least hydrogen and optionally also a carbon carrier is supplied to a reduction reactor containing a material containing a metal oxide, and a top gas containing hydrogen is discharged from the reduction reactor,

[0017] Features

[0018] supplying a portion of the top gas as a component of the fuel gas to a gas burner for preparing a reducing gas,

[0019] And when the hydrogen ratio in the reducing gas and / or the top gas increases, the water vapor content in the fuel gas is increased.

[0020] The material containing a metal oxide is preferably a material containing an iron oxide.

[0021] The reducing gas contains at least hydrogen as a reducing component. It can also consist only of hydrogen. The reducing gas optionally also contains one or more gaseous carbon carriers as additional reducing components or components. The carbon carriers are provided, for example, by natural gas; these are, for example, carbon monoxide CO or methane CH4 introduced or produced by natural gas.

[0022] The hydrogen can be, for example, green, blue, grey, turquoise or pink hydrogen. These "colors" are understood to refer to the coloration associated with the type of production on which it is based. Green hydrogen is produced, for example, by water electrolysis with the aid of electricity generated by renewable energy sources, or by gasification or fermentation of biomass, or steam reforming of biogas - the common point of the types of production of green hydrogen is that the production is CO2-free. In the case of blue hydrogen, the CO2 produced in the production is stored so that it does not enter the atmosphere; for example if it is produced by sequestration of the resulting carbon dioxide CO2. In the case of turquoise hydrogen, it is produced by separating the resulting carbon C. In the case of pink hydrogen, the hydrogen is produced by using nuclear power. Grey hydrogen is produced from fossil fuels - for example from natural gas by means of steam reforming - where the resulting CO2 is mainly released into the atmosphere. Other colors of hydrogen are also conceivable. Mixtures of one or more of these "colors" of hydrogen are also conceivable.

[0023] When the carbon support is present as an additional reducing component: the ratio of the proportion of hydrogen to the carbon support in the reducing gas can be varied, for example by incorporating different amounts when preparing the reducing gas. For example, it can be varied so that the proportion of hydrogen in the reducing gas is increased.

[0024] The reducing gas is a gas introduced into the reduction reactor having a composition and temperature at the time of introduction. Before determining the composition and temperature, the reducing gas is in the form of a precursor, on the basis of which the reducing gas is prepared. The preparation may include, for example, the addition of other components, heating, reforming. The preparation may also include chemical reactions carried out in the precursor without external intervention, which may change, for example, the chemical composition or temperature. In the event of changes in the preparation, the proportion of hydrogen in the reducing gas may change. In any case, a gas burner is used when preparing the reducing gas, for example, for heating and / or reforming.

[0025] The reduction reactor is, for example, a reduction shaft, for example a reduction shaft with a fixed bed of a material containing metal oxides in the case of a direct reduction process. The reduction reactor is, for example, a fluidized bed reactor, for example a reduction reactor with a fluidized bed of a material containing metal oxides in the case of a direct reduction process. A fluidized bed reactor can also include a plurality of individual subreactors, which are connected, for example, in parallel or in series and together form a fluidized bed reactor.

[0026] The reduction reactor is, for example, a fluidized bed reactor, for example a reduction reactor with a fluidized bed of metal oxide-containing material in the case of a direct reduction process. The fluidized bed reactor can also include a plurality of individual subreactors, which are connected, for example, in parallel or in series and together form a fluidized bed reactor.

[0027] The top gas is discharged from the reduction reactor. The top gas is formed by the reducing gas when it flows through the reduction reactor, because the components of the top gas react with the metal oxide-containing material in the reduction reactor, or with the products formed in these reactions, such as the formation of metallic iron. Due to the reduction reaction in the reduction reactor, the reducing power of the top gas is lower than that of the reducing gas. The top gas contains hydrogen. The gas burner requires fuel gas for combustion. A part of the top gas is supplied to the gas burner for preparing the reducing gas as a component of the fuel gas required for combustion; in the case of multiple gas burners, it is supplied to at least one gas burner. For example, 100Nm 3 10Nm in top gas 3 A partial amount is used as a component of the fuel gas. Before being used as a component of the fuel gas, the top gas may be subjected to a treatment step; for example, the top gas may be subjected to dedusting, heating, cooling, or adjustment of the water vapor content of the top gas.

[0028] That portion of the top gas may be one of several components of the fuel gas, for example when another gas having a calorific value (e.g. natural gas) is admixed and the gas mixture is now used as fuel gas. That portion of the top gas may also be the only component of the fuel gas; in this case, the fuel gas corresponds to the portion. When the fuel gas has several components: the fuel gas is produced by combining all the components of the fuel gas; before all the components are combined, a fuel gas precursor is present. Measures which increase the water vapor content in one or more components of the fuel gas or in the fuel gas precursor also lead to an increase in the water vapor content in the fuel gas.

[0029] When the proportion of hydrogen in the reducing gas and / or the top gas increases, the water vapor content in the fuel gas is increased. For this purpose, measures are taken, which result in additional water vapor in the fuel gas compared to a comparative state. The increase in the water vapor content in the fuel gas is preferably controlled in an open-loop and / or closed-loop manner, i.e. by using a device for open-loop and / or closed-loop control of the water vapor content in the fuel gas. In this case, the open-loop and / or closed-loop control is performed to reach a target value or a target value range. The target value or the target value range is derived, for example, from the desired degree of reduction of the adiabatic flame temperature and / or from the desired limitation of the temperature peak in the flame.

[0030] The increase in the proportion of hydrogen in the reducing gas and / or in the top gas is determined by means of a device for detecting an increase in the proportion of hydrogen in the reducing gas and / or in the top gas or by means of a device for determining the hydrogen content in the reducing gas and / or in the top gas. When determining the hydrogen content in the reducing gas and / or in the top gas, an increase in the proportion of hydrogen in the reducing gas and / or in the top gas can also be detected.

[0031] The proportion of hydrogen H 2 in the fuel gas is preferably at least 65% by volume, more preferably at least 70% by volume—in each case based on a water content of 0% by volume in the fuel gas.

[0032] Advantageous Effects of the Invention

[0033] During combustion, the increased water vapor content in the fuel gas results in a lower adiabatic flame temperature than the same fuel gas except for the increased water vapor content. Thus, the problems of nitrogen oxide formation and heat transfer at higher adiabatic flame temperatures due to the increased hydrogen content mentioned at the beginning can be reduced or avoided.

[0034] It is also advantageous here that the reduction in the adiabatic flame temperature achieved according to the invention does not require a reduction in the temperature levels of the fuel gas and the oxidizing gas. Thus, a constant amount of heat can be extracted from the exhaust gases of the gas burner by heat exchange, which is advantageous for the release of the exhaust gases to the environment. Releasing the exhaust gases at a higher temperature - because less heat is extracted into the fuel gas and the oxidizing gas to achieve a reduction in the flame temperature by the lower temperature of these gases - is disadvantageous, because the energy extracted by heat exchange is of a smaller amount.

[0035] The water vapor content of the top gas is usually adjusted to a target value in order to ensure properties that are as reproducible as possible for well-controlled further utilization of the top gas. For this purpose, a regulation with water countercurrent is usually carried out, which is carried out in a gas conditioner. For example, different partial quantities of the top gas for various uses with different requirements for the water vapor content (e.g., use as a component of a reducing gas, use as a component of a fuel gas) are usually conditioned in different gas conditioning channels with differently temperature-controlled water.

[0036] In one embodiment, the water vapor content in the fuel gas is increased by increasing the temperature of the water used to condition that portion of the top gas. The portion of the top gas leaving the gas conditioner is saturated; as the temperature of the water increases, the temperature of the portion of the top gas leaving the gas conditioner and therefore the amount of water vapor contained in the saturated state increases.

[0037] Typically, during regulation, the top gas used as a component of the reducing gas is regulated using hot water in a dedicated gas regulation channel. Compared to a first state in which the top gas has a specific water vapor content before regulation and a specific predetermined target for water vapor content after regulation: the higher the water vapor content of the top gas before regulation (i.e., the more water that must be condensed to establish an unchanged predetermined target), the more advantageous it is to use water with a lower temperature than in the first state for regulation. Therefore, the demand for hot water provided for producing the first state decreases. In one embodiment, the temperature of the water used to regulate the portion of the top gas provided as a component of the fuel gas (which may account for a portion of the water used to regulate the top gas, or may be all of the water used to regulate the top gas) is increased by using hot water used to regulate the top gas provided as a component of the reducing gas. Thus, even if the demand for hot water used to regulate the reducing gas decreases, the infrastructure for producing hot water can be rationally utilized.

[0038] In one embodiment, the water vapor content in the fuel gas is increased by adding water H2O to the fuel gas or to a component or precursor of the fuel gas. Thus, water H2O may be added to one or more or all of the following three members:

[0039] - fuel gas,

[0040] - the composition of the fuel gas,

[0041] - Precursor of fuel gas.

[0042] Water can be in liquid H2O f Water H2O can be added in the form of water vapor H2O g The fuel gas is added in the form of a precursor. The fuel gas is formed by combining all of the components of the fuel gas. Before all of the components are combined, the fuel gas is in the form of a precursor.

[0043] In a variant of the method according to the invention, the fuel gas or the fuel gas precursor is heated before the fuel gas is burned. This is achieved, for example, by heat exchange with exhaust gases from a reformer and / or a gas heating device; for example, exhaust gases from a reformer and / or a gas heating device operated by a gas burner supplied with fuel gas. Preferably, water H2O is added to the fuel gas or the fuel gas precursor after heating the fuel gas or the fuel gas precursor. Due to the higher temperature, more water H2O can be absorbed. This is particularly advantageous when a component of the fuel gas is hydrogen H2 which is added, because hydrogen H2 is usually essentially dry, so that after its entry into the gas mixture, the percentage water content of the gas mixture decreases.

[0044] As mentioned above, before the top gas is used as a component of the fuel gas, the top gas can be subjected to a treatment step, such as dedusting. In one embodiment, the top gas used as a component of the fuel gas is at least partially dry-dedusted. In dry dedusting, water vapor content losses hardly occur, and when the water vapor content is increased, this loss must be compensated again; it is therefore advantageous to dry-dedust that portion of the top gas provided as a component of the fuel gas. When a component of the fuel gas is added hydrogen H2, it is advantageous to add this hydrogen after dry dedusting. This is because hydrogen H2 is usually essentially dry, so that after it enters the gas mixture, the percentage of water content of the gas mixture decreases. After dry dedusting, the water vapor content is usually high enough so that the reduction due to the addition of hydrogen can reach or exceed the required minimum value without any cost or only with little cost.

[0045] In the case of dry dedusting, there is hardly any appreciable loss of heat. Therefore, in the case of dry dedusting, the fuel gas does not need to be preheated or only needs to be preheated less. The remaining energy in the top gas can be used, for example, to preheat hydrogen, combustion air or process or reducing gas.

[0046] Another subject of the present application is a device for reducing a material containing metal oxides,

[0047] It includes:

[0048] - reduction reactor,

[0049] - a top gas discharge pipe for discharging top gas from the reduction reactor,

[0050] - a preparation device comprising at least one gas burner for preparing a reducing gas,

[0051] a supply conduit for supplying a partial amount of top gas as a component of the fuel gas to the at least one gas burner,

[0052] Characterized in that it also includes

[0053] - At least one member selected from the following two members:

[0054] a) at least one device for determining the water vapor content in the reducing gas and / or top gas,

[0055] and

[0056] b) a device for detecting an increase in the proportion of hydrogen in the reducing gas and / or in the top gas,

[0057] - means for open-loop and / or closed-loop control of the water vapor content in the fuel gas with reference to the hydrogen content in the reducing gas and / or top gas.

[0058] The apparatus for reducing a material containing metal oxides may include one or more reduction reactors. The apparatus for reducing a material containing metal oxides may further include a reducing gas supply conduit through which a reducing gas is supplied to the reduction reactor.

[0059] The apparatus for reducing the material containing metal oxides may include one or more top gas exhaust pipes. The apparatus for reducing the material containing metal oxides may include one or more preparation equipment for preparing reducing gas. The preparation equipment for preparing reducing gas may include one or more gas burners.

[0060] The device for reducing a material containing metal oxides may comprise one or more supply conduits for supplying a portion of the amount of top gas as a fuel gas component to the at least one gas burner; these supply conduits are suitable for supplying a portion of the amount of top gas together with other components of the fuel gas as fuel gas to the gas burner. The other components of the fuel gas may be fed, for example, via a feed conduit which opens into a supply conduit conducting the portion of the amount of top gas, thereby producing the fuel gas.

[0061] The device for reducing a material containing metal oxides comprises at least one device for determining the water vapor content in the reducing gas and / or the top gas; it may also comprise a plurality of such devices. The water vapor content can be determined, for example, based on a calculation based on the gas temperature and / or the water temperature.

[0062] The device for reducing the material containing metal oxides comprises means for open-loop and / or closed-loop control of the water vapor content in the fuel gas with reference to the hydrogen content in the reducing gas and / or the top gas; it may also comprise a plurality of such means.

[0063] By means of such a device, the purpose of open-loop and / or closed-loop control of the water vapor content in the fuel gas by referring to the hydrogen content in the reducing gas and / or the top gas can be achieved. Thus, the method of the present invention can be carried out.

[0064] Of course, in the apparatus for reducing a material containing metal oxides of the present invention, there is also a reducing gas supply conduit through which a reducing gas containing at least hydrogen and optionally further containing a carbon carrier is supplied to the reduction reactor.

[0065] In one variant of the device for reducing metal oxide-containing materials according to the invention, there is also a feed duct for conducting further fuel gas components to the gas burner.

[0066] In one variant, the device for reducing a material containing metal oxides according to the invention comprises a device for detecting an increase in the proportion of hydrogen in the reducing gas and / or the top gas. This can be used to detect whether the proportion of hydrogen in the reducing gas and / or the top gas has increased. The device for detecting an increase in the proportion of hydrogen in the reducing gas and / or the top gas can be integrated in the device for determining the water vapor content in the reducing gas and / or the top gas, so that there is only a single device with two applicabilities - or it can be performed separately from the device for determining the water vapor content in the reducing gas and / or the top gas, so that there are two devices - a device for detecting an increase in the proportion of hydrogen in the reducing gas and / or the top gas, and a device for determining the hydrogen content in the reducing gas and / or the top gas. The device for detecting an increase in the proportion of hydrogen in the reducing gas and / or the top gas is preferably a device for determining the hydrogen content in the reducing gas and / or the top gas.

[0067] In one embodiment, the device for open-loop and / or closed-loop control of the water vapor content in the fuel gas by reference to the hydrogen content in the reducing gas and / or the top gas comprises at least one gas regulator. In the gas regulator, the gas is regulated as a function of its water vapor content, which means that measures are taken which lead to a target value for the water vapor content. The measure in the gas regulator is to conduct the gas flow to be regulated in countercurrent with water. Here, heat and water are exchanged between the gas phase and the liquid phase.

[0068] In the device of the invention, the gas regulator is configured to operate at different water temperatures. For this purpose, it can, for example, have different water supply pipes, which are respectively connected to water from different temperature-controlled water sources. For this purpose, it can, for example, have a heating device and / or a cooling device for heating and / or cooling the supplied water.

[0069] In one embodiment, the gas regulator has a fuel gas regulating channel and a reducing gas regulating channel, wherein the fuel gas regulating channel is used to regulate the furnace top gas provided as a component of the fuel gas by supplying water for fuel gas regulation, and the reducing gas regulating channel is used to regulate the furnace top gas provided as a component of the reducing gas by supplying hot water for reducing gas regulation, wherein the hot water supply for reducing gas regulation is suitable for supplying hot water for fuel gas regulation to at least one fuel gas regulating channel.

[0070] In one embodiment, the apparatus for reducing the metal oxide-containing material comprises a H2O addition conduit adapted to add liquid water H2O f and / or gaseous water H2O g (i.e. water vapor) is introduced into a pipe which conducts,

[0071] -Fuel gas

[0072] or

[0073] - Composition of the fuel gas.

[0074] For example, the HO addition line can open into a line conducting the fuel gas. Alternatively, it can open into a line conducting a component of the fuel gas, for example into a supply line for supplying a portion of the top gas as a component of the fuel gas to the at least one gas burner; this opening can be arranged upstream and / or downstream (seen in the flow direction towards the gas burner) of the opening of the feed line.

[0075] In one embodiment, the apparatus for reducing metal oxide-containing material comprises a dry dedusting apparatus for dry dedusting top gas; it is preferably adapted to dry dedusting at least a partial amount of top gas used as a component of the fuel gas.

[0076] Another subject of the present application is a signal processing device with a machine-readable program code, characterized in that the device has open-loop and / or closed-loop control commands for carrying out the method according to the invention. Another subject is a signal processing device for carrying out the method according to any one of claims 1 to 5.

[0077] Another subject of the present application is a machine-readable program code for a signal processing device, characterized in that the program code has open-loop and / or closed-loop control commands, which cause the signal processing device to perform the method according to the invention. Another subject is a computer program product, which contains commands for a signal processing device, which, when executing the program for the signal processing device, cause it to perform the method according to any one of claims 1 to 5.

[0078] Another subject of the present application is a storage medium on which the machine-readable program code of the present invention is stored. Another subject is a storage medium on which a computer program for carrying out the method according to any one of claims 1 to 5 is stored. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] The present invention is exemplarily described below with reference to a number of schematic diagrams.

[0081] Figure 1 An embodiment of the device according to the invention is shown schematically.

[0082] Figure 2 Schematically shows the Figure 1 A substantially similar embodiment, wherein details of the H2O addition conduit are shown.

[0083] Figure 3 Schematically shows the Figure 1 and Figure 2 A substantially similar embodiment, wherein details of dry dust collection are shown.

[0084] Figure 4 A further embodiment of the device according to the invention is schematically shown.

[0085] Figure 5 A variant which utilizes top gas which is not used for fuel gas is schematically shown.

[0086] Implementation Description Example

[0087] Figure 1 A device 1 for reducing a material 2 containing metal oxides having a reduction reactor 3 is schematically shown. The material 2 containing metal oxides is introduced into the reduction reactor 3. The device 1 for reducing the material 2 containing metal oxides also includes a reducing gas supply conduit 4, through which a reducing gas containing at least hydrogen and optionally also a carbon carrier is supplied to the reduction reactor 3. Through a top gas discharge conduit 5, a top gas containing hydrogen is discharged from the reduction reactor 3. The reducing gas is prepared in a preparation device 7 for preparing reducing gas, which includes a gas burner 6. The gas burner 6 is operated using fuel gas. A portion of the top gas is supplied to the gas burner 6 as a component of the fuel gas; this is accomplished by a supply conduit 8 for supplying a portion of the top gas as a component of the fuel gas to the gas burner 6. There is also a device 9 for measuring the reducing gas and the top gas. It is used to detect whether the proportion of hydrogen in the reducing gas and / or the top gas has increased. The position for measuring the hydrogen proportion shown is not necessarily as shown. Figure 1as shown; the hydrogen proportion can also be determined at different locations; for example, it can be determined after dry dust removal. By reference to the hydrogen content in the reducing gas and / or the top gas, the water vapor content of the fuel gas is increased using the device 10 for open-loop and / or closed-loop control of the water vapor content in the fuel gas, which is also present, as shown by the dashed circle around the component of the fuel gas or the partial section of the pipeline that conducts the fuel gas to the gas burner 6. The additional fuel gas component is conducted to the gas burner 6 via the feed pipeline 11; since the pipeline 11 and the supply pipeline 8 are connected together, the top gas and the additional fuel gas component are combined in the figure; the combination of the additional fuel gas component and the top gas produces the fuel gas, which is conducted to the gas burner 6.

[0088] In a variant, the device 10 for open-loop and / or closed-loop control of the water vapor content in the fuel gas by reference to the hydrogen content in the reducing gas and / or the top gas comprises a gas regulator, which is not shown separately for the sake of greater clarity. The gas regulator is configured to operate at different water temperatures. To this end, it can have, for example, different water supply pipes, which are respectively connected to water from different temperature-controlled water sources. To this end, it can, for example, have a heating device and / or a cooling device for heating and / or cooling the supplied water. Thereby, the water vapor content in the fuel gas is increased by increasing the temperature of the water used to regulate that amount of top gas.

[0089] In a variant not shown separately, the gas conditioner has a fuel gas conditioning channel with a water supply for fuel gas conditioning and a reducing gas conditioning channel with a hot water supply for reducing gas conditioning. Here, the hot water supply for reducing gas conditioning is suitable for supplying hot water for fuel gas conditioning to at least one fuel gas conditioning channel. The temperature of the water used for conditioning that amount of top gas can then be increased by using the hot water for conditioning the top gas provided as a component of the reducing gas.

[0090] Figure 2 With Figure 1 A substantially similar diagram shows how H2O addition conduits 12a, 12b, 12c exist. These conduits are used to add liquid water H2O f and / or gaseous water H2O g The H2O addition conduit 12a leads to the conduit for conducting the fuel gas. The H2O addition conduits 12b and 12c lead to the conduits for conducting the fuel gas components. Thus, the water vapor content in the fuel gas can be increased by adding water H2O to the fuel gas or the fuel gas precursor or the fuel gas component.

[0091] Figure 3 With Figure 1 and Figure 2 A substantially similar figure shows how the device 1 for reducing metal oxide-containing materials comprises a dry dedusting device 13 for dry dedusting of top gas. It is suitable for dry dedusting at least a part of the amount of top gas used as a fuel gas component, since it is arranged in the supply duct 8. In a variant not shown separately, the device 10 for open-loop and / or closed-loop control of the water vapor content in the fuel gas can be implemented so that it can influence the temperature in the dry dedusting device and in this way the water vapor content in the fuel gas can be controlled in an open-loop and / or closed-loop manner.

[0092] Figure 4 and Figure 1 Basically similarly, a device 1 for reducing a material 2 containing metal oxides having a reduction reactor 3 is schematically shown. The material 2 containing metal oxides is introduced into the reduction reactor 3. The device 1 for reducing the material 2 containing metal oxides also includes a reducing gas supply conduit 4, through which a reducing gas containing at least hydrogen and optionally also a carbon carrier is supplied to the reduction reactor 3. The top gas containing hydrogen is discharged from the reduction reactor 3 through a top gas discharge conduit 5. The reducing gas is prepared in a preparation device 7 for preparing reducing gas, which includes a gas burner 6. The gas burner 6 is operated with fuel gas. A part of the top gas is supplied to the gas burner 6 as a fuel gas component; this is achieved by a supply conduit 8 for supplying a part of the top gas as a fuel gas component to the gas burner 6. There is also a device 9a for detecting an increase in the hydrogen proportion in the reducing gas and / or the top gas. The device 9a is used to detect whether the hydrogen proportion in the reducing gas and / or the top gas has increased. The position for measuring the hydrogen proportion shown does not necessarily have to be as shown. Figure 4 As shown; the hydrogen ratio can also be measured at other locations; for example, it can be measured after dry dust removal.

[0093] The device 9a for detecting an increase in the proportion of hydrogen in the reducing gas and / or the top gas is, in the case shown, a device for determining the hydrogen content in the reducing gas and / or the top gas. With reference to the hydrogen content in the reducing gas and / or the top gas, the water vapor content in the fuel gas is increased using the device 10 for open-loop and / or closed-loop control of the water vapor content in the fuel gas, which is also present, as indicated by the dashed circle around a component of the fuel gas or a section of the pipeline that conducts the fuel gas to the gas burner 6. The additional fuel gas component is conducted to the gas burner 6 via a feed pipeline 11; since the pipeline 11 and the supply pipeline 8 are connected together, the top gas and the additional fuel gas component are combined in the figure; the combination of the additional fuel gas component and the top gas produces the fuel gas, which is conducted to the gas burner 6.

[0094] In a variant, the device 10 for open-loop and / or closed-loop control of the water vapor content in the fuel gas by reference to the hydrogen content in the reducing gas and / or the top gas comprises a gas regulator, which is not shown separately for the sake of greater clarity. The gas regulator is configured to be able to operate at different water temperatures. To this end, it can, for example, have different water supply pipes, which are respectively connected to water from different temperature-regulated water sources. To this end, it can, for example, have a heating device and / or a cooling device for heating and / or cooling the supplied water. Thus, the water vapor content in the fuel gas is increased by increasing the temperature of the water used to regulate that amount of top gas.

[0095] In a variant not shown separately, the gas conditioner has a fuel gas conditioning channel with a water supply for fuel gas conditioning and a reducing gas conditioning channel with a hot water supply for reducing gas conditioning. The hot water supply for reducing gas conditioning is suitable for supplying hot water for fuel gas conditioning to at least one fuel gas conditioning channel. The temperature of the water used for conditioning the partial amount of top gas can then be increased by using the hot water for conditioning the top gas provided as a component of the reducing gas.

[0096] Figure 2 and 3 The contents shown in can also be similar to their Figure 1 The combination of the contents in Figure 4 The content in the combination, rather than with Figure 1 The content combination in .

[0097] For greater clarity, Figures 1 to 4 It is not shown what can be achieved with the top gas which is not used as fuel gas component. Figure 5 A variation of how this exploitation can be performed is schematically shown, similar to Figure 1 The top gas is combined with a reducing gas precursor 14 (e.g. natural gas and / or hydrogen) and the mixture is introduced into a preparation device for preparing a reducing gas. The top gas is thus used as a reducing gas precursor. Such recycling of the top gas and its use in the preparation of a reducing gas is known and is therefore not described in detail. Figure 5 The variants shown in the present invention with regard to the use of top gas not used as a fuel gas component are similar to those shown in the present invention with regard to the use of top gas not used as a fuel gas component Figures 2 to 4 The content combination shown in .

[0098] Figure 1 , 3 The feed pipe 11 in and 4 is optional; there may also be a similar Figure 1 , 3 and 4, but the feed pipe 11 may not be present.

[0099] Reference numerals list

[0100] 1. Apparatus for reducing materials containing metal oxides

[0101] 2 Materials containing metal oxides

[0102] 3 Reduction reactor

[0103] 4 Reduction gas supply pipeline

[0104] 5 Top gas exhaust pipe

[0105] 6 Gas burners

[0106] 7. Preparation equipment for preparing reducing gas

[0107] 8 Supply pipeline

[0108] 9. Device for determining the water vapor content in reducing gas and / or top gas

[0109] 9a Device for detecting an increase in the proportion of hydrogen in reducing gas and top gas

[0110] 10 Device for open-loop and / or closed-loop control of water vapor content in fuel gas

[0111] 11 Feed Pipe

[0112] 12a, 12b, 12c H2O addition pipeline

[0113] 13 Dry dust removal device

[0114] 14 Reducing gas precursor.

Claims

1. A method for reducing a material containing a metal oxide, wherein a reducing gas containing at least hydrogen and optionally also a carbon carrier is supplied to a reduction reactor (3) containing a material containing a metal oxide, and a top gas containing hydrogen is discharged from the reduction reactor (3), Features A portion of the top gas is supplied as a component of the fuel gas to a gas burner (6) for preparing a reducing gas, And when the hydrogen ratio in the reducing gas and / or the top gas increases, the water vapor content in the fuel gas is increased.

2. The method according to claim 1, wherein the top gas is regulated in a gas conditioner in countercurrent with water, characterized in that: The water vapor content of the fuel gas is increased by increasing the temperature of the water used to condition that amount of top gas.

3. The method according to claim 2, characterized in that The temperature of the water used for adjusting the amount of top gas provided as a component of the fuel gas is increased by using the hot water used for adjusting the top gas provided as a component of the reducing gas.

4. The method according to any one of claims 1 to 3, characterized in that The water vapor content in the fuel gas is increased by adding water H2O to the fuel gas and / or a precursor of the fuel gas and / or a component of the fuel gas.

5. The method according to any one of claims 1 to 4, characterized in that The top gas used as a component of the fuel gas is at least partially dry-dedusted.

6. A device (1) for reducing a material (2) containing metal oxides, It includes: - a reduction reactor (3), - a top gas discharge line (5) for discharging top gas from the reduction reactor (3), - a preparation device (7) comprising at least one gas burner (6) for preparing a reducing gas, a supply conduit (8) for supplying a partial amount of top gas as a component of the fuel gas to the at least one gas burner (6), Characterized in that it also includes - At least one member selected from the following two members: a) at least one device (9) for determining the water vapor content in the reducing gas and / or top gas, and b) a device (9a) for detecting an increase in the proportion of hydrogen in the reducing gas and / or in the top gas, - means (10) for open-loop and / or closed-loop control of the water vapor content in the fuel gas with reference to the hydrogen content in the reducing gas and / or the top gas.

7. The device according to claim 6, characterized in that The device (10) for open-loop and / or closed-loop control of the water vapor content in the fuel gas with reference to the hydrogen content in the reducing gas and / or the top gas comprises at least one gas regulator.

8. The device according to claim 7, characterized in that The gas regulator has a fuel gas regulating passage and a reducing gas regulating passage, the fuel gas regulating passage being used to regulate the top gas provided as a component of the fuel gas by supplying water for fuel gas regulation, The reducing gas regulating passage is used to regulate the top gas provided as a component of the reducing gas by supplying hot water for reducing gas regulation, The hot water supply for reducing gas conditioning is adapted to supply hot water for fuel gas conditioning to at least one fuel gas conditioning passage.

9. The device according to any one of claims 6 to 8, characterized in that The apparatus for reducing a material containing metal oxides comprises H2O addition conduits 12a, 12b, 12c, which are suitable for adding liquid water H2O f and / or gaseous water H2O g Introduced into a pipeline that conducts the following substances -Fuel gas or - Composition of the fuel gas.

10. The device according to any one of claims 6 to 9, characterized in that The device comprises a dry dedusting device (13) for dry dedusting of top gas, which is preferably suitable for dry dedusting at least a partial amount of top gas used as a component of the fuel gas.

11. A signal processing device having a machine-readable program code, characterized in that It has open-loop and / or closed-loop control commands for carrying out the method according to the invention. Another subject matter is a signal processing device for carrying out the method according to any one of claims 1 to 5.

12. Machine readable program code for a signal processing device, characterized in that The program code has open-loop and / or closed-loop control commands for causing the signal processing device to execute the method according to any one of claims 1 to 5 .

13. A storage medium having stored thereon the machine-readable program code according to claim 12.

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