Reduction of materials containing metal oxides based on ammonia nh3 and carbon-containing gases

Abstract

A method for reducing a material containing metal oxides, wherein a reducing gas obtained by utilizing ammonia (NH3) and a carbon-containing gas is used. In the production of the reducing gas, a first gas stream containing ammonia is subjected to ammonia cracking, thereby producing a cracked gas stream. A second gas stream containing carbon is reformed, thereby producing a reformed gas stream. At least a portion of the cracked gas stream and at least a portion of the reformed gas stream are combined. The heat generated during the reforming process is provided to the ammonia cracking. An apparatus (10) for reducing a material containing metal oxides includes: a reduction unit (30), a reducing gas input line (40) leading to the reduction unit (30), a first gas stream line (50) for ammonia-containing gas, a second gas stream line (70) for carbon-containing gas, an ammonia cracking unit (60), a reforming unit (80), a cracked gas stream line (61), a reformed gas stream line (81), and a combined gas stream line (90). A first gas flow line (50) leads into the ammonia cracking unit (60), and a second gas flow line (70) leads into the reforming unit (80). A cracked gas flow line (61) extends from the ammonia cracking unit (60), and a reformed gas flow line (81) extends from the reforming unit (80). The cracked gas flow line (61) and the reformed gas flow line (81) are connected to a combined gas flow line (90). A heating device (100) is provided to supply the heat generated during the reforming process in the reforming unit (80) to the ammonia cracking unit (60).

Description

Technical Field

[0001] This application relates to a method and apparatus for reducing materials containing metal oxides, wherein a reducing gas obtained by utilizing ammonia (NH3) and a carbon-containing gas is used. Existing technology

[0002] It is known to use reducing gases to reduce materials containing metal oxides, such as iron oxides, like ores. This includes direct reduction using reducing gases in reduction units, such as reduction shafts; and in blast furnace methods, where carbon monoxide (CO) is used as the reducing gas in the blast furnace. In conventional methods currently used on a large industrial scale, the reducing gas is primarily based on carbon-containing gases, such as natural gas or coke oven gas. This results in the generation of large quantities of carbon dioxide (CO2), which is particularly undesirable for environmental policy reasons.

[0003] To reduce CO2 emissions during the reduction of materials containing metal oxides, hydrogen (H2) is known to be used as a reducing gas. Here, hydrogen can be used as the sole reducing gas or in combination with other gases, such as natural gas-based reducing gases. The higher the proportion of CO2-neutral hydrogen (H2) in the reducing gas, the less CO2 is emitted.

[0004] However, due to its physical properties, storing hydrogen (H2) and transporting it from production sites to consumption sites is problematic and involves significant costs.

[0005] To reduce CO2 emissions during the reduction of materials containing metal oxides, ammonia (NH3) is also known to be used as a reducing agent. Ammonia has significant advantages over hydrogen (H2) in terms of storage and transportation.

[0006] Ammonia can be broken down into nitrogen and hydrogen. .

[0007] Hydrogen gas (H2) can act as a reducing agent in reactions with metal oxides, such as iron oxides. .

[0008] However, ammonia itself can also act as a reducing agent: .

[0009] In principle, materials containing metal oxides can also be reduced using a reducing gas obtained by utilizing ammonia (NH3); therefore, the reducing gas can be, for example, ammonia (NH3), or a mixture of ammonia (NH3) and one or more other gases (preferably one or more that have a reducing effect on materials containing metal oxides), as is the case, for example, with a mixture of ammonia and its cracking products (i.e., hydrogen (H2) and nitrogen (N2), wherein the mixture may of course also contain other gases. However, the reducing gas obtained by utilizing ammonia (NH3) can also be a reducing gas that does not contain ammonia (NH3) but contains hydrogen (H2) obtained by cracking (alone or together with nitrogen (N2)), which is optionally mixed with one or more other gases (preferably one or more that have a reducing effect on materials containing metal oxides).

[0010] The reduction reaction that produces metallic iron (Fe) from hydrogen (H2) and ammonia (NH3), as well as the cracking of ammonia into nitrogen (N2) and hydrogen (H2), is endothermic. This leads to problems regarding the thermodynamic and kinetic conditions required to sustain the reduction on an industrial scale.

[0011] The balance between the goal of reducing CO2 emissions by increasing the use of ammonia (NH3) and the problems associated with ammonia utilization can be achieved through the combined use of ammonia and carbon-containing gases. Summary of the Invention

[0012] Technical Purpose The purpose of this invention is to provide the possibility of using ammonia and carbon-containing gases in combination during the reduction of materials containing metal oxides.

[0013] Technical solution The objective is achieved by reducing materials containing metal oxides. The reducing gas used is obtained by utilizing ammonia (NH3) and carbon-containing gases, and is introduced into the reduction unit. in In the process of reducing gas production The first gas stream containing ammonia is subjected to ammonia cracking, simultaneously generating a cracked gas stream; and The second gas stream containing carbon is reformed, and a reformed gas stream is generated simultaneously. At least a portion of the cracked gas stream and at least a portion of the reformed gas stream are combined, and the combined gas stream obtained during the combination contributes to the reducing gas. Its characteristic feature is that the heat generated during the reforming process is provided to ammonia cracking.

[0014] The material containing metal oxides is preferably a material containing iron oxides.

[0015] The reduction method is, for example, the direct reduction method.

[0016] The reducing gas is obtained by utilizing ammonia (NH3), with ammonia contributing to the reduction. For example, the reducing gas is a mixture of ammonia (NH3) and one or more other gases. However, the reducing gas obtained by utilizing ammonia (NH3) can also be a reducing gas that does not contain ammonia (NH3) but contains hydrogen (H2) (alone or together with nitrogen (N2)), a cracking product obtained from ammonia cracking, mixed with one or more other gases. The first gas stream can be pure ammonia or a mixture of gases containing ammonia.

[0017] Therefore, the reducing gas may contain ammonia; it is composed in part of ammonia and other components. Preferably, components that have a reducing effect on materials containing metal oxides are other components of the reducing gas; such components may be, for example, hydrocarbon-containing gases, carbon-containing gases, hydrogen-containing gases, or hydrogen. According to the invention, the reducing gas is obtained by utilizing ammonia, wherein the ammonia is cracked, and the resulting cracked gas stream containing nitrogen and hydrogen, and optionally ammonia—optionally enriched with hydrogen or depleted with nitrogen—contributes to the reducing gas. Ammonia contributes to the reducing gas; this contribution exists in addition to the contribution of carbon-containing gases to the reducing gas. Ammonia provides other components of the reducing gas besides those contributed by utilizing carbon-containing gases.

[0018] Ammonia cracking is carried out under ammonia cracking conditions with a lower limit of 350°C, preferably 450°C, and an upper limit of 650°C, preferably 550°C. To achieve ammonia cracking, a catalyst that catalyzes ammonia cracking within this temperature range is used. This produces a cracked gas stream containing nitrogen and hydrogen—optionally ammonia. If not all the ammonia in the first gas stream reacts under ammonia cracking conditions, but only a portion of the ammonia in the first gas stream reacts, then the cracked gas stream also contains ammonia. Unreacted residual ammonia from the first gas stream exists in the cracked gas stream as ammonia. A maximum ammonia content of 10% by volume, preferably 8% by volume, and more preferably 6% by volume, in the cracked gas stream is acceptable.

[0019] In principle, ammonia of various "colors" is acceptable. "Color" here is understood to refer to a color associated with the type of production on which it is based. The color of ammonia is generally related to the color of the hydrogen used in its production. For example, ammonia can be green, if it is produced using green hydrogen; it can be blue, if it is produced using hydrogen obtained through the sequestration of carbon dioxide (CO2). Ammonia can also be produced using turquoise hydrogen, if it is produced by separating carbon (C); it can be produced using pink hydrogen, if it is produced using nuclear power. Mixtures of one or more of these "colors" of ammonia, or mixtures of the colors of the hydrogen on which ammonia is based, can also be considered.

[0020] The reducing gas is obtained by utilizing a carbon-containing gas stream (here, the second gas stream). This gas stream contains carbon-containing gases. These carbon-containing gases can be pure gases, such as pure methane, or they can be a mixture of gases, such as natural gas or coke oven gas. The carbon in the carbon-containing gas can be, for example, hydrocarbons, such as methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H). 10 It may exist, for example, in the form of carbon monoxide (CO) or carbon dioxide (CO2). The carbon-containing gas used may be, for example, natural gas, or top gas discharged from the reduction unit—optionally after processing.

[0021] Carbon-containing gases contribute to the reducing gas; this contribution exists in addition to the contribution of ammonia to the reducing gas. Besides the components contributed by ammonia, carbon-containing gases provide other components of the reducing gas. These other components of the reducing gas are preferably components that have a reducing effect on materials containing metal oxides; they can be, for example, hydrocarbon-containing gases, carbon-containing gases, hydrogen-containing gases, and hydrogen gas.

[0022] According to the present invention, the utilization of carbon-containing gas is achieved by reforming the carbon-containing gas. The carbon-containing gas is subjected to reforming conditions at a temperature with a lower limit of 700°C and an upper limit of 1150°C, preferably 1000°C. Reforming refers to the reforming of the carbon-containing gas. Reforming conditions refer to the conditions under which the carbon-containing gas undergoes reforming. Reforming conditions exist in the reforming apparatus to make it suitable for the reforming of carbon-containing gas. To achieve the reforming conditions, a catalyst that catalyzes reforming within this temperature range—a so-called reforming catalyst—is used. Direct reduced iron (DRI) can also serve as a reforming catalyst.

[0023] For example, reforming is carried out according to the following formula as steam reforming and / or CO2 reforming: .

[0024] The reforming process is illustrated using methane (CH4) as an example; for more advanced hydrocarbon compounds, the reforming process is similar.

[0025] In the production of reducing gas, at least a portion of the cracked gas stream and at least a portion of the reformed gas stream are combined. According to the invention, the heat generated during the reforming process is supplied to the ammonia cracking process that produces the cracked gas stream.

[0026] For a cracked gas stream, the utilization of a portion of the gas stream can occur either when only a portion of the volume of the cracked gas stream is utilized while the composition of the cracked gas stream remains unchanged, or when not all components of the cracked gas stream are utilized—for example, when a certain component is enriched or depleted and the corresponding enriched or depleted gas stream is fully or partially utilized.

[0027] For reformed gas streams, the utilization of a portion of the volume exists both when only a portion of the volume of the generated reformed gas stream is utilized while the composition of the reformed gas stream remains unchanged, and when not all components of the generated reformed gas stream are utilized—that is, for example, when a certain component is enriched or depleted and the corresponding enriched or depleted gas stream is fully or partially utilized.

[0028] A reducing gas is a gas introduced into a reduction apparatus or its internal space containing a material containing a metal oxide (in which a reduction reaction occurs), having the composition and temperature present upon introduction. Prior to the presence of this composition and temperature, a reducing gas precursor on which the preparation of the reducing gas is based exists. This preparation can be achieved, for example, by adding other components or by heating. The preparation can also be achieved through a chemical reaction in the precursor without external intervention, such as altering the chemical composition or temperature.

[0029] Reduction units can be, for example, reduction shafts, such as fixed-bed reduction shafts containing materials containing metal oxides in direct reduction processes. Reduction units can also be, for example, fluidized-bed reactors, such as reduction units containing fluidized-bed reactors containing materials containing metal oxides in direct reduction processes. Fluidized-bed reactors can also comprise multiple independent sub-reactors, which are connected in parallel or series to form a fluidized-bed reactor. For example, a reduction unit can be a fluidized-bed reactor—such as a reduction unit containing fluidized-bed reactors containing materials containing metal oxides in direct reduction processes. Fluidized-bed reactors can also comprise multiple independent sub-reactors, which are connected in parallel or series to form a fluidized-bed reactor. A reduction unit can also be a blast furnace containing a fixed-bed reactor containing materials containing metal oxides—in which case ammonia can replace, for example, PCI coal or fossil reducing gases during blast furnace operation.

[0030] Advantages of the present invention Ammonia cracking is a strongly endothermic reaction (+93 kJ / mol). Therefore, ammonia cracking leads to a significant local temperature drop, which is undesirable in both reforming and reduction units.

[0031] Steam reforming and CO2 reforming and The reforming reaction of ammonia is carried out using a catalyst at temperatures of 700–1150 °C for kinetic and thermodynamic reasons. If the temperature during ammonia cracking is also within this range, it will lead to extremely rapid decomposition of ammonia, resulting in a rapid and significant local temperature drop. This temperature drop during the reforming process can have adverse effects, such as reduced natural gas conversion or carbon deposition. or ) .

[0032] To avoid this unfavorable interaction between ammonia cracking and reforming, ammonia cracking and reforming are performed on different gas streams—a first gas stream containing ammonia and a second gas stream containing carbon; these two gas streams—the cracked gas stream and the reformed gas stream—are then combined. According to the invention, the heat generated during reforming contributes to the energy required to sustain endothermic ammonia cracking. Therefore, ammonia cracking and reforming work together not only materially but also energetically in the production of reducing gas, thereby achieving efficient implementation of the method. The heat generated during reforming is, for example, waste heat generated during reforming. The heat generated during reforming is understood, for example, to refer to: the hot waste gas generated during reforming, for example, due to the combustion process that provides heat for carrying out reforming and is carried out by means of a burner; this hot waste gas—which contains waste heat generated during reforming—can be utilized so that its heat—i.e., waste heat generated during reforming—is used for ammonia cracking. If the ammonia cracking unit is integrated into certain parts of the reforming unit, waste heat can be provided to ammonia cracking via thermal radiation and / or convection.

[0033] To assist in the endothermic cracking of ammonia, in addition to or replacing the heat generated during the reforming process, waste heat from the reduction unit where the reduction is carried out, waste heat from the melting unit used to melt the reduction products, electrical energy, or steam generated from these heat sources can also be utilized. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source can also be utilized.

[0034] If, for example, reduction products—such as DRI direct reduced iron or sponge iron—are melted in melting devices such as EAF, OBF, submerged arc furnace, or furnace during steelmaking and exhaust gases are generated simultaneously, the heat extracted from the exhaust gases of the melting device can be provided to ammonia cracking.

[0035] If heat is supplied via a burner during the reforming process, flue gas is generated. This flue gas, or the sealing gas obtained from it (an inert gas with a composition, for example, about 78% N2, 20% CO2, 1% O2, and 1% H2O), can contribute to heating to the temperature required for ammonia cracking (NH3). According to one embodiment, the heat supplied for ammonia cracking is at least partially provided by the flue gas.

[0036] Reforming is carried out in a reforming unit.

[0037] During the reduction of materials containing metal oxides, a top gas is generated, which can optionally be used, at least in part, for the production of reducing gases after processing. The processing includes, for example, dust removal, cooling, reducing and / or adjusting water vapor content, enriching or depleting certain components.

[0038] The top gas is discharged from the reduction unit. The top gas is formed by the reaction of the reducing gas as it flows through the reduction unit, due to the reaction of its components with materials containing metal oxides or products generated during the reaction (e.g., metallic iron). Because of the reduction reaction occurring in the reduction unit, the reducing power of the top gas is lower than that of the reducing gas. A portion or all of the top gas can—optionally after processing—be used as a component in the preparation of the reducing gas. Utilization of a portion exists both when only a fraction of the volume of the top gas produced is used while the composition of the top gas remains unchanged, and when not all components of the top gas are utilized—that is, for example, a certain component is enriched (e.g., hydrogen is enriched) and the corresponding enriched gas stream is utilized in whole or in part.

[0039] In a preferred embodiment, the treatment is carried out without reducing the carbon dioxide content.

[0040] In a preferred embodiment, the nitrogen content is reduced during the treatment process. For this purpose, for example, a device that separates nitrogen gas (N2) can be used.

[0041] If only a portion of the top gas is used to produce the reducing gas, the amount of nitrogen circulating into the reducing gas is reduced because, correspondingly, not all the nitrogen contained in the top gas enters the reducing gas. The top gas not used as a component in the preparation of the top gas can, for example, be used as a fuel component in the burner of a reforming unit.

[0042] In a preferred embodiment, the energy for the ammonia cracking process is provided at least in part by electrical heating. Alternatively or additionally, waste heat from the reduction unit, or waste heat from the melting unit used to melt the reduction products, or heat from the top gas, or steam generated from these heat sources, may also be utilized. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater, or steam generated from such a heat source, may also be utilized.

[0043] In a preferred embodiment, heat extracted from the top gas is provided to the ammonia cracking process.

[0044] In a preferred embodiment, heat is supplied to ammonia cracking indirectly, for example, through a heat exchanger or through a heat transfer medium (e.g., steam).

[0045] In a preferred embodiment, energy for the reforming process is provided at least in part by electric heating. Alternatively or additionally, waste heat from the reduction unit, or waste heat from the melting unit used to melt the reduction products, or waste heat from the reforming unit, or heat from the top gas, or steam generated from these heat sources may also be utilized. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater, or steam generated from such a heat source, may also be utilized.

[0046] In a preferred embodiment, the first gas stream is heated before it undergoes ammonia cracking. The advantage of heating the first gas stream prior to ammonia cracking is that it establishes temperature conditions favorable for ammonia cracking. The energy provided during heating is already present in the first gas stream. For example, the energy supplied for heating the first gas stream can be provided through heat exchange with the waste gas produced during reforming.

[0047] Alternatively or additionally, electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction products, heat from the top gas, or steam generated from these heat sources can also be utilized. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source can also be utilized.

[0048] In a preferred embodiment, the second gas stream is heated before it undergoes reforming. The advantage of heating the second gas stream prior to reforming is that it allows for the establishment of temperature conditions favorable for reforming. The energy provided during heating is already present in the second gas stream and does not need to be provided during reforming. This prevents it from entering the reforming unit too cold and thus avoiding carbon buildup.

[0049] For example, energy can be supplied for heating by exchanging heat with the waste gas produced by reforming.

[0050] Alternatively or additionally, electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction products, waste heat from the reforming apparatus, or the heat from the top gas, or steam generated from these heat sources, may also be utilized. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater, or steam generated from such a heat source, may also be utilized.

[0051] In a preferred embodiment, the ratio of the pyrolysis gas stream to the reformed gas stream can be changed during the merging process. Hydrogen (H2) can also be added to the reducing gas precursor during the production of the reducing gas. In another preferred embodiment, the ratio of ammonia to hydrogen in the reducing gas can be changed. For example, the amount of hydrogen (H2) added can be increased or decreased, or the amount of ammonia can be increased or decreased.

[0052] A combined gas stream is generated during the merging of the cracked gas stream and the reformed gas stream. This combined gas stream contributes to the reducing gas; the combined gas stream can be the reducing gas or a reducing gas precursor.

[0053] In one approach, ammonia is added to the combined gas stream during the production of the reducing gas. In addition to the reducing components already present in the combined gas stream, the ammonia also contributes to the reducing power of the reducing gas.

[0054] However, preferably, the majority of the ammonia used to produce the reducing gas is used to generate the cracked gas stream, with only a small fraction of the total ammonia amount added to the combined gas stream. The combined gas stream may also contain ammonia, as, as mentioned above, the cracked gas stream may still contain ammonia. The ammonia content can be increased by adding ammonia to the combined gas stream.

[0055] In one embodiment, ammonia is added to the reduction apparatus for reducing materials containing metal oxides, in addition to introducing a reducing gas; in another embodiment, this is done independently of introducing a reducing gas. Besides the reducing gas, the ammonia can also contribute to the reduction. However, preferably, the majority of the ammonia is used to generate the cracked gas stream, with only a small fraction of the total ammonia amount added to the reduction apparatus.

[0056] The concentration of NH3 in the reducing gas should not exceed 10% by volume, preferably not more than 8% by volume, and particularly preferably not more than 6% by volume.

[0057] In one embodiment, ammonia added to the combined gas stream and / or reduction unit is heated. This can be achieved, for example, by utilizing waste heat from the reforming process. For instance, pipeline sections in heat exchangers can be used to heat the top gas fuel by exchanging heat with the waste heat from the reforming unit. The top gas fuel is a portion of the top gas that, optionally, is used as a fuel component for burners operating in the reforming unit after processing.

[0058] Alternatively or additionally, electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction products, heat from the top gas, or steam generated from these heat sources can also be utilized. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source can also be utilized.

[0059] Preferably, for the portion of the cracked gas stream or the portion of the cracked gas stream that is combined with at least a portion of the reformed gas stream, the ammonia content is not reduced—for example, in an NH3 absorber or a so-called NH3 stripper; in this respect, the feed for merging is carried out directly.

[0060] Another subject of this invention is: Apparatus for reducing materials containing metal oxides It includes: - Reduction device, - The reducing gas input line into the reduction unit. - For the first gas flow line containing ammonia gas - Second gas flow line for carbon-containing gases - Ammonia cracking unit, - Reforming unit, - Pyrolysis gas flow line, - Reformer gas flow line, - Combine gas flow lines, The first gas flow line leads to the ammonia cracking unit. Furthermore, the second gas flow line leads to the reforming unit. Furthermore, the cracked gas flow line extends from the ammonia cracking unit. Furthermore, the reformed gas flow line extends from the reforming unit. Furthermore, the pyrolysis gas flow line and the reforming gas flow line are connected to the merging gas flow line. Furthermore, the combined gas flow line (90) is connected to the reducing gas input line (40). Its features are, There is a heating device used to supply the heat generated during the reforming process in the reforming unit to the ammonia cracking unit.

[0061] The method of the present invention can be implemented using this device.

[0062] Existing apparatuses for reducing materials containing metal oxides, including reforming devices, can be readily modified into the apparatuses of this invention, thereby enabling them to implement the methods of this invention.

[0063] There may be one or more restoration devices.

[0064] There may be one or more reducing gas input lines.

[0065] There may be one or more ammonia cracking units.

[0066] There may be one or more reforming units. The reforming unit can be internal or external. If internal, it also processes the top gas from the reduction unit; therefore, the top gas is the internal source of carbon-containing gas in the operation of this method. If external, it does not process the top gas, but only the carbon-containing gas supplied from an external source.

[0067] One or more gas heaters may be present to heat the reducing gas precursor.

[0068] There may be one or more cracked gas flow lines.

[0069] There may be one reformer gas flow line or multiple reformer gas flow lines.

[0070] There may be one or more merged gas flow lines.

[0071] The combined gas flow line is connected to the reducing gas input line.

[0072] In the reduction apparatus, materials containing metal oxides are reduced using a reducing gas. The reducing gas is introduced into the reduction apparatus through a reducing gas inlet line.

[0073] The first gas flow line delivers ammonia-containing gas. In one embodiment, a heating device for heating the ammonia-containing gas is provided in the first gas flow line; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas produced from reforming.

[0074] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction product, heat from the top gas, or steam generated from these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source may also be utilized.

[0075] A first gas flow line leads into the ammonia cracking unit—thus supplying ammonia-containing gas to the ammonia cracking unit via the first gas flow line. In the ammonia cracking unit, ammonia cracking conditions exist at a lower limit of 350°C, preferably 450°C, and an upper limit of 650°C, preferably 550°C. At least a portion of the ammonia in the ammonia-containing gas is cracked in the ammonia cracking unit, simultaneously generating cracked gas. A cracked gas flow line extends out from the ammonia cracking unit.

[0076] The second gas flow line transports carbon-containing gas. In one embodiment, the second gas flow line includes a heating device for heating the carbon-containing gas; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas produced during reforming.

[0077] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction product, heat from the top gas, or steam generated from these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source may also be utilized.

[0078] A second gas flow line leads into the reforming unit—thus, carbon-containing gas is supplied to the reforming unit via the second gas flow line. In the reforming unit, reforming conditions exist at a temperature ranging from a lower limit of 700°C to an upper limit of 1150°C, preferably 1000°C. At least a portion of the carbon-containing gas undergoes reforming in the reforming unit. Reformed gas is generated in the reforming unit. The reformed gas flow line extends out of the reforming unit.

[0079] In one embodiment, a heating device for heating the pyrolysis gas stream is present in the pyrolysis gas stream pipeline; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas generated from reforming.

[0080] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction product, heat from the top gas, or steam generated from these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source may also be utilized.

[0081] In one embodiment, a heating device for heating the reforming gas stream is present in the reforming gas stream pipeline; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas produced during reforming.

[0082] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction product, heat from the top gas, or steam generated from these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source may also be utilized.

[0083] The cracked gas stream line and the reformed gas stream line lead into the merging gas stream line. The merging gas stream line is used to transport a mixture of the cracked gas stream and the reformed gas stream. The merging gas stream line may include a gas mixer region; in one embodiment, the cracked gas stream line and the reformed gas stream line lead into the gas mixer region, where the cracked gas stream and the reformed gas stream are merged and mixed by the gas mixer, and the resulting mixture is further transported in the merging gas stream line.

[0084] In one embodiment, the combined gas flow pipeline includes a heating device for heating the combined gas flow; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas produced by reforming.

[0085] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction product, heat from the top gas, or steam generated from these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source may also be utilized.

[0086] In one implementation, there is no device for reducing ammonia content in the cracked gas flow line.

[0087] In one embodiment, in the gas flow direction toward the reduction unit, there is no device for reducing ammonia content after the ammonia cracking unit.

[0088] The device of the present invention is characterized in that: There is a heating device used to supply the heat generated during the reforming process in the reforming unit to the ammonia cracking unit.

[0089] In one embodiment, the ammonia cracking unit includes a heat exchanger for exchanging heat with the flue gas produced by the reforming unit as a heating device for supplying heat generated during the reforming process in the reforming unit to the ammonia cracking unit. If heating is provided using a burner in the reforming unit, flue gas is generated. The flue gas can be discharged from the reforming unit via a flue gas discharge line. The heat in the flue gas can be utilized by guiding the flue gas discharge line through the heat exchanger in the ammonia cracking unit during the ammonia cracking process. In one embodiment, hot flue gas can be guided through the ammonia cracking unit; for example, if the mixture flows through pipelines containing a catalyst in the ammonia cracking unit, the flue gas can be guided around these pipelines to transfer heat.

[0090] Waste heat from the reduction unit, or waste heat from the melting unit used to melt the reduction products, or heat from the top gas, can also be used to provide heat to the ammonia cracking unit. Alternatively or additionally, electrical energy, waste heat from the reduction unit, waste heat from the melting unit used to melt the reduction products, heat from the top gas, or steam generated from these heat sources can also be used. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source can also be used.

[0091] In one embodiment, the ammonia cracking unit includes an electric heating device. The electric heating device uses electrical energy for heating.

[0092] Alternatively or additionally, a heating device may be provided that utilizes the waste heat of the reduction apparatus, or the waste heat of the melting apparatus used to melt the reduction product, or the heat of the top gas, or steam generated by these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat of the gas heater, or steam generated by such a heat source, may also be utilized.

[0093] In one embodiment, the ammonia cracking unit is designed as an ammonia cracker; the ammonia cracker is a separate unit from the reforming unit. In another embodiment, the ammonia cracking unit is designed to be integrated into certain parts of the reforming unit. For example, the reforming unit is a reformer that contains multiple pipes filled with catalyst material for reforming within a housing. By also arranging the pipes filled with catalyst material for ammonia cracking (which constitute the ammonia cracking unit) within the housing of the reformer, the ammonia cracking unit can, for example, be integrated into the reforming unit or certain parts of the reformer. If heat is supplied to the reforming unit using a burner, flue gas is generated by the combustion process. This flue gas generated from reforming can surround the pipes filled with catalyst material for ammonia cracking within the housing of the ammonia cracking unit, simultaneously providing heat to the ammonia cracking unit.

[0094] In one embodiment, the reforming apparatus includes an electric heating device. The electric heating device uses electrical energy for heating.

[0095] Alternatively or additionally, a heating device may be provided that utilizes the waste heat of the reduction apparatus, or the waste heat of the melting apparatus used to melt the reduction product, or the heat of the top gas, or steam generated by these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat of the gas heater, or steam generated by such a heat source, may also be utilized.

[0096] In one embodiment, the apparatus for reducing a material containing metal oxides includes a top gas discharge line for discharging top gas from the reduction apparatus. In a preferred embodiment, the top gas discharge line leads to a second gas flow line for carbon-containing gas. In one embodiment, the top gas discharge line includes at least one processing device. This processing device performs actions such as dust removal, cooling, reducing and / or regulating water vapor content, and enriching or depleting certain components.

[0097] Preferably, the top gas exhaust line does not include any device for reducing carbon dioxide levels. Preferably, the top gas exhaust line includes at least one device for separating nitrogen (N2).

[0098] Preferably, at least one fuel line extends from the top gas discharge line, which is used to supply top gas as fuel components for the burners of the reforming unit.

[0099] In a preferred embodiment, the apparatus for reducing a material containing metal oxides includes means for controlling and / or adjusting the ratio of ammonia to hydrogen in the reducing gas. This apparatus includes sensors for measuring the ammonia and hydrogen content in the reducing gas.

[0100] In one preferred embodiment, the apparatus for reducing a material containing metal oxides includes at least one hydrogen addition line for adding hydrogen (H2) to a combined gas stream line. The hydrogen addition line is connected to the combined gas stream line. In another preferred embodiment, the apparatus for reducing a material containing metal oxides includes at least one ammonia addition line for adding ammonia to a combined gas stream line. The ammonia addition line is connected to the combined gas stream line.

[0101] In a preferred embodiment, the apparatus for reducing a material containing metal oxides includes at least one ammonia supply line for adding ammonia to the reduction apparatus—in addition to the introduction of a reducing gas or in addition to a reducing gas inlet line; the addition of ammonia to the reduction apparatus can be carried out independently of the introduction of a reducing gas. The ammonia supply line leads into the reduction apparatus.

[0102] In one embodiment, the ammonia supply line includes a heating device for heating the ammonia; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas produced by reforming. Here, in order to utilize the waste heat produced by reforming, pipeline sections in the heat exchanger can be used, for example, to heat the top gaseous fuel by exchanging heat with the waste heat from the reformer.

[0103] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, waste heat from the melting apparatus used to melt the reduction product, heat from the top gas, or steam generated from these heat sources for heating. If the reducing gas precursor is heated by a gas heater, the waste heat from the gas heater or steam generated from such a heat source may also be utilized.

[0104] Another subject of this application is a signal processing apparatus having machine-readable program code, characterized in that the apparatus includes control and / or regulation instructions for implementing the method of the present invention. Another subject is a signal processing apparatus for implementing the method according to any one of claims 1 to 8.

[0105] Another subject of this application is machine-readable program code for a signal processing apparatus, characterized in that the program code contains control and / or regulation instructions that cause the signal processing apparatus to implement the method of the present invention. Another subject is a computer program product containing instructions for a signal processing apparatus that, when the program of the signal processing apparatus is executed, cause the signal processing apparatus to implement the method according to any one of claims 1 to 8.

[0106] Another subject of this application is a storage medium storing machine-readable program code of the present invention. Another subject is a storage medium storing a computer program for implementing the method according to any one of claims 1 to 8. Brief description of the attached diagram The present invention is described below by way of several schematic diagrams.

[0108] Figure 1 The illustration schematically shows one embodiment of the method of the invention in one aspect of the apparatus for reducing materials containing metal oxides. Figure 2 Another option is shown schematically. Figure 3 Another solution was shown. Figure 4 Another option is illustrated schematically.

[0109] Implementation plan description. Example

[0110] Figure 1An apparatus 10 for reducing a metal oxide-containing material 20 is schematically shown. The metal oxide-containing material 20 is fed into a reduction apparatus 30. A reducing gas is introduced through a reducing gas inlet line 40 into the reduction apparatus 30 to reduce the metal oxide-containing material 20. The reducing gas is produced using ammonia (NH3) and a carbon-containing gas.

[0111] To this end, the first gas stream containing ammonia is subjected to ammonia cracking, thereby producing a cracked gas stream. This first gas stream containing ammonia is then fed into an ammonia cracking unit 60 via a first gas stream line 50, where at least a portion of the ammonia in the ammonia-containing gas stream is cracked. The second gas stream containing carbon is reformed, thereby producing a reformed gas stream. This second gas stream containing carbon is then fed into a reforming unit 80 via a second gas stream line 70, where reforming takes place.

[0112] In the ammonia cracking unit 60, ammonia cracking conditions exist at a lower limit of 350°C, preferably 450°C, and an upper limit of 650°C, preferably 550°C. At least a portion of the ammonia in the ammonia-containing gas is cracked in the ammonia cracking unit 60, generating cracked gas. The cracked gas flow line 61 extends from the ammonia cracking unit 60.

[0113] In the reforming unit 80, reforming conditions exist at a temperature with a lower limit of 700°C and an upper limit of 1150°C, preferably 1000°C. In the reforming unit 80, at least a portion of the carbon-containing gas undergoes reforming. In the reforming unit 80, a reformed gas stream is obtained. A reformed gas stream line 81 extends from the reforming unit 80.

[0114] The cracked gas flow line 61 and the reformed gas flow line 81 are connected to the merging gas flow line 90, thus enabling and allowing the merging of at least a portion of the cracked gas flow and at least a portion of the reformed gas flow during the reducing gas production process. The merging gas flow line 90 may include a gas mixer region; however, this is not shown separately for clarity. The merging gas flow line 81 is connected to the reducing gas input line 40.

[0115] The heat generated during the reforming process is supplied to the ammonia cracking unit. For this purpose, a heating device 100—shown as a wavy line between the reforming unit 80 and the ammonia cracking unit 60—is provided to supply the heat generated during the reforming process in the reforming unit 80 to the ammonia cracking unit 60. The heating device 100 may be a heat exchanger for exchanging heat with the flue gas from the reforming unit.

[0116] A heating device for heating ammonia may be present in the first gas flow line 60 for ammonia-containing gas, but it is not shown separately for clarity.

[0117] A heating device for heating the carbon-containing gas may be present in the second gas flow line 50 for the carbon-containing gas, but it is not shown separately for clarity.

[0118] The ammonia cracking unit 60 may optionally include an electric heating device 101; the optional electric heating device 101 is schematically indicated by a lightning bolt symbol. Optionally, there may also be a heating device that utilizes waste heat from the reduction unit, or waste heat from the melting unit used to melt the reduction products, or heat from the top gas, or steam generated from these heat sources, or waste heat from the gas heater, but for clarity this is not shown separately.

[0119] The ammonia cracking unit 60 may optionally include an electric heating device 101; the optional electric heating device 101 is schematically indicated by a lightning bolt symbol. Optionally, there may also be a heating device that utilizes waste heat from the reduction unit, or waste heat from the melting unit used to melt the reduction products, or heat from the top gas, or steam generated from these heat sources, or waste heat from the gas heater, but for clarity this is not shown separately.

[0120] The reforming unit 80 may optionally include an electric heating device 102. The electric heating device uses electrical energy for heating.

[0121] Alternatively or additionally, there may be heating devices that utilize the waste heat of the reduction apparatus, or the waste heat of the melting apparatus used to melt the reduction products, or the heat of the top gas, or the steam generated by these heat sources, or the waste heat of the gas heater for heating, but for clarity this is not shown separately.

[0122] The cracked gas flow line 61 may optionally include a heating device for heating the cracked gas flow, but this is not shown separately for clarity.

[0123] The reformed gas flow line 81 may optionally include a heating device for heating the cracked gas flow, but this is not shown separately for clarity.

[0124] The combined gas flow line 90 may optionally contain a heating device for heating the combined gas flow, but this is not shown separately for clarity.

[0125] There is no device for reducing ammonia content in the combined gas flow line 90.

[0126] In the apparatus 10 for reducing the metal oxide-containing material 20, there is no apparatus for reducing the ammonia content after the ammonia cracking unit 60 in the gas flow direction toward the reduction unit 30.

[0127] Figure 1 In this unit, the ammonia cracking unit 60 is designed as an ammonia cracker unit separate from the reforming unit 80.

[0128] Figure 2 Showing with Figure 1 A substantially identical embodiment, differing only in the design of the ammonia cracking unit 60. The ammonia cracking unit 60 is schematically shown as being designed for integration into a portion of the reforming unit 80. The ammonia cracking unit 60 includes piping containing catalyst material for ammonia cracking; piping 62 is shown.

[0129] The ammonia cracking unit 60 is integrated into certain parts of the reforming unit 80.

[0130] The reforming unit 80 is a reformer containing multiple pipes (not shown) filled with catalyst material for reforming within a housing 82. The ammonia cracking unit 60 is integrated into a portion of the reforming unit 80 by also arranging pipes 62 filled with catalyst material for ammonia cracking within the housing 82. Flue gas is generated by the combustion process when heat is supplied to the reforming unit using a burner. The flue gas from the reforming unit can surround the pipes 62 filled with catalyst material for ammonia cracking within the housing 82 of the ammonia cracking unit 60, simultaneously providing heat to the ammonia cracking unit 60.

[0131] Figure 3 Showing with Figure 1 The design is essentially the same, except that an alternative is shown where a top gas discharge line 110 is provided for discharging the top gas from the reduction unit 30. The top gas discharge line 110 leads to a second gas flow line 70 for carbon-containing gases. An optional—and therefore indicated by dashed lines—processing unit 120 is also shown, in the case shown, which is a dust removal device. The top gas discharge line 110 does not include any device for reducing the carbon dioxide content.

[0132] The top gas exhaust line 110 may include means for separating nitrogen (N2), but this is not shown separately for clarity. A fuel line may extend from the top gas exhaust line for supplying top gas as a fuel component for the burners of the reforming unit 80, but this is not shown separately for clarity.

[0133] Figure 4 Showing with Figure 1 The design is essentially the same. We will now only discuss the additional features shown: - The apparatus 10 for reducing the metal oxide-containing material 20 further includes a device 130 for controlling and / or adjusting the ratio of ammonia to hydrogen in the reducing gas. A sensor 140 for determining the ammonia and hydrogen content in the reducing gas is also shown. - The apparatus 10 for reducing the metal oxide-containing material 20 further includes a hydrogen addition line 150 for adding hydrogen H2 to the combined gas flow line 90. The hydrogen addition line 150 is connected to the combined gas flow line 90; - The apparatus 10 for reducing the metal oxide-containing material 20 further includes an ammonia addition line 160 for adding ammonia to the combined gas flow line 90. The ammonia addition line 160 is connected to the combined gas flow line 90; The apparatus 10 for reducing the metal oxide-containing material 20 also includes an ammonia supply line 170 for adding ammonia to the reduction apparatus 30. The ammonia supply line 170 enters the reduction apparatus 30 independently of the introduction of reducing gas.

[0134] A heating device for heating ammonia may be present in the ammonia supply line 170; for example, a heat exchanger, which is used, for example, to exchange heat with the waste gas produced by reforming. Here, in order to utilize the waste heat produced by reforming, for example, by using pipeline sections in the heat exchanger, these pipeline sections can also be used to heat the top gas fuel by exchanging heat with the waste heat of the reforming unit. Waste heat from the reduction unit, or waste heat from the melting unit for melting the reduction products, or heat from the top gas, or waste heat from the gas heater, or steam generated from these heat sources may also be utilized. However, for clarity, this is not shown separately.

[0135] Alternatively or additionally, a heating device may be provided that utilizes electrical energy, waste heat from the reduction apparatus, or waste heat from the melting apparatus used to melt the reduction products, or heat from the top gas, or waste heat from the gas heater, or steam generated from these heat sources for heating. However, this is not shown separately for clarity.

[0136] List of reference numerals 10. Apparatus for reduction 20 Materials containing metal oxides 30 Reduction Device 40 Reducing gas inlet line 50 First gas flow line (for ammonia-containing gas) 60 Ammonia Cracking Unit 61. Pyrolysis Gas Flow Line 62 Pipeline (containing catalyst material for ammonia cracking) 70 Second gas flow line (for carbon-containing gases) 80 Reforming Unit 81 Reformer Gas Flow Line 82. Outer shell 90 Combined gas flow lines 100 Heating Units 101 Electric heating device 102 Electric heating device 110 Top gas exhaust line 120 processing device 130 Apparatus for controlling and / or adjusting the ratio of ammonia and hydrogen in a reducing gas. 140 sensors 150 Hydrogen Addition Line 160 Ammonia Addition Line 170 Ammonia supply pipeline.

Claims

1. A method for reducing a material containing metal oxides, wherein a reducing gas obtained by utilizing ammonia (NH3) and a carbon-containing gas is introduced into a reduction apparatus. in In the production process of reducing gas, the first gas stream containing ammonia is subjected to ammonia cracking, simultaneously generating a cracked gas stream; and The second gas stream containing carbon is reformed, and a reformed gas stream is generated simultaneously. At least a portion of the cracked gas stream and at least a portion of the reformed gas stream are combined, and the combined gas stream obtained during the combination contributes to the reducing gas. Its features are, The heat generated during the reforming process is supplied to ammonia cracking.

2. The method according to claim 1, wherein flue gas is generated during the reforming process, characterized in that, The heat provided for ammonia cracking is at least partially provided by the flue gas.

3. The method according to any one of claims 1 to 2, wherein a portion or all of the top gas is used as a component in the preparation of the reducing gas after treatment, characterized in that, The treatment was carried out without reducing the carbon dioxide content.

4. The method according to any one of claims 1 to 3, wherein a portion or all of the top gas is used as a component in the preparation of the reducing gas after treatment, characterized in that, The nitrogen content is reduced during the treatment process.

5. The method according to any one of claims 1 to 4, characterized in that... Ammonia is added to the combined gas stream during the production of reducing gas.

6. The method according to any one of claims 1 to 5, wherein the reduction of the metal oxide-containing material is carried out in a reduction apparatus (30), characterized in that, In addition to introducing reducing gas, ammonia is also added to the reduction device (30).

7. The method according to any one of claims 1 to 6, characterized in that, The concentration of NH3 in the reducing gas does not exceed 10% by volume, preferably not more than 8% by volume, and even more preferably not more than 6% by volume.

8. The method according to any one of claims 1 to 7, characterized in that, For the portion of the cracked gas stream, or the portion of the cracked gas stream that is set to be combined with at least a portion of the reformed gas stream, no ammonia content reduction is performed.

9. An apparatus (10) for reducing materials containing metal oxides, It includes: - Reduction device (30), - The reducing gas input line (40) into the reduction device (30), - For the first gas flow line (50) containing ammonia gas, - Second gas flow line (70) for carbon-containing gases, - Ammonia cracking unit (60), - Reforming unit (80), - Pyrolysis gas flow line (61), - Reformer gas flow line (81), - Combine gas flow lines (90), The first gas flow line (50) leads to the ammonia cracking unit (60). Furthermore, the second gas flow line (70) leads into the reforming unit (80). Furthermore, the cracked gas flow line (61) extends from the ammonia cracking unit (60). Furthermore, the reforming gas flow line (81) extends from the reforming unit (80), Furthermore, the pyrolysis gas flow line (61) and the reforming gas flow line (81) are connected to the merging gas flow line (90). Furthermore, the combined gas flow line (90) is connected to the reducing gas input line (40). Its features are, There is a heating device (100) for supplying the heat generated during the reforming process in the reforming unit (80) to the ammonia cracking unit (60).

10. The apparatus according to claim 9, characterized in that, There is no device for reducing ammonia content in the cracked gas flow line (61).

11. The apparatus according to claim 9 or 10, characterized in that, In the gas flow direction toward the reduction unit (30), there is no device for reducing the ammonia content after the ammonia cracking unit (60).

12. The apparatus according to any one of claims 9 to 11, comprising a top gas discharge line (110) for discharging top gas from the reduction apparatus (30), characterized in that, The top gas exhaust line (110) does not include any device for reducing carbon dioxide levels.

13. The apparatus according to any one of claims 9 to 12, comprising a top gas discharge line (110) for discharging top gas from the reduction apparatus (30), characterized in that, The top gas discharge line (110) includes at least one device for separating nitrogen (N2).

14. The apparatus according to any one of claims 9 to 13, characterized in that, It includes at least one ammonia addition line (160) for adding ammonia to the combined gas flow line (90).

15. The apparatus according to any one of claims 9 to 14, characterized in that, It includes at least one ammonia supply line (170) for adding ammonia to the reduction unit (30).

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