Combined system for producing steel, and method for operating the combined system
Patent Information
- Application Number
- EP2024709411
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-16
- Filing Date
- 2024-03-08
- Publication Date
- 2026-01-21
AI Technical Summary
The existing steel production plant networks face challenges in reducing CO2 emissions and achieving a sustainable energy balance, with high CO2 footprints due to fluctuations in gas composition and inefficient use of blast furnace gases.
A plant network that includes a blast furnace, converter steelworks, hydrogen production system, and chemical plant, where a mixing device adjusts the stoichiometric ratio of gases to facilitate a water-gas shift reaction, converting CO into hydrogen and reducing CO2 emissions, and utilizes hydrogen-rich gases for chemical production, enabling efficient energy utilization and carbon capture.
This approach reduces CO2 emissions by converting CO2 into hydrogen, enhancing the efficient use of blast furnace gases, and stabilizes the operation of the chemical plant under dynamic loads, achieving a more sustainable energy balance and lower carbon footprint.
Smart Images
Figure EP2024056153_19092024_PF_FP_ABST
Abstract
Description
[0001] Plant network for steel production and a method for operating the plant network
[0002] The invention relates to a plant network for steel production and a method for operating the plant network
[0003] State of the art
[0004] The steel production plant network comprises a blast furnace for pig iron production, a converter steelworks for crude steel production, a network of pipelines for gases generated during pig iron production and / or crude steel production, and a chemical plant connected to the gas pipeline system.
[0005] In the chemical plant, chemical products can be produced from the supplied gas streams, each of which contains the components of the final product.
[0006] In the blast furnace, pig iron is extracted from iron ores, additives, coke, and other reducing agents such as coal, oil, gas, biomass, recycled waste plastics, or other carbon and / or hydrogen-containing materials. CO, CO2, and especially hydrogen and water vapor are inevitably produced as products of the reduction reactions. Blast furnace top gas extracted from the blast furnace process, also referred to as blast furnace top gas and / or blast furnace gas, often has a high nitrogen content in addition to the aforementioned components and may also contain impurities. The gas quantity and composition of the blast furnace top gas depend on the feedstock and the operating mode and are subject to fluctuations. Typically, however, blast furnace top gas contains 35 to 60 vol.% N2, 20 to 30 vol.% CO, 20 to 30 vol.% CO2, and 2 to 15 vol.% H2.Approximately 30 to 40% of the blast furnace top gas generated during pig iron production is typically used to heat the hot blast for the blast furnace process in hot blast furnaces; the remaining blast gas can also be used externally in other plant areas, for example, for heating purposes or to generate electricity.
[0007] In the converter steelworks, which follows the blast furnace process, pig iron is converted into crude steel. By blowing oxygen onto the liquid pig iron, harmful impurities such as carbon, silicon, sulfur, and phosphorus are removed. Since the oxidation processes generate considerable heat, scrap is often used in quantities of up to
[0008] REPLACEMENT SHEET (RULE 26) is added as a coolant at a rate of 25% based on the pig iron. Lime is also added for slag formation and alloying agents. A converter gas is withdrawn from the steel converter, which has a high CO content and also contains nitrogen, hydrogen, and CO2. A typical converter gas composition is 50 to 70 vol.% CO, 10 to 20 vol.% N2, approximately 15 vol.% CO2, and approximately 2 vol.% H2. The converter gas is either flared or, in modern steelworks, captured and used for energy recovery.
[0009] The plant network can optionally be operated in conjunction with a coking plant. In this case, the plant network described above also includes a coke oven plant, in which coal is converted into coke through a coking process. The coking of coal into coke produces coke oven gas that has a high hydrogen content and considerable amounts of CH4. Typically, coke oven gas contains 55 to 70 vol.% H2, 20 to 30 vol.% CH4, 5 to 10 vol.% N2, and 5 to 10 vol.% CO. Coke oven gas also contains CO2, NH3, and H2S. In practice, coke oven gas is used, for example, in various plant areas for heating purposes and in the power plant process for electricity generation. Furthermore, it is known to use coke oven gas together with blast furnace top gas or converter gas to generate synthesis gases.
[0010] In an integrated steelworks operated in conjunction with a coking plant, approximately 40 to 50% of the raw gases generated as blast furnace top gas, converter gas, and coke oven gas are used for process engineering. Approximately 50 to 60% of the resulting gases are fed to the power plant and used to generate electricity. The electricity generated in the power plant covers the electricity demand for pig iron and crude steel production. Ideally, the energy balance is closed, so that apart from iron ore and carbon in the form of coal and coke as energy sources, no further energy input is required, and no product leaves the plant complex other than crude steel and slag.
[0011] The current state of the art is problematic due to high CO2 emissions, particularly a large CO2 footprint.
[0012] Against this background, the invention is based on the object of improving the sustainability of the overall process and the CO2 balance, in particular CO2 emissions, and reducing the CO2 footprint while at the same time enabling stable, continuous and sustainable operation of plants.
[0013] REPLACEMENT SHEET (RULE 26) Disclosure of the invention
[0014] This object is achieved with a plant network for steel production according to claim 1 and a method for operating a plant network according to claim 8.
[0015] The subject matter of the invention is a plant network for steel production comprising a blast furnace for pig iron production, a converter steelworks for crude steel production, a blast furnace gas pipeline system for gases arising during pig iron production, a network pipeline system for gases arising during pig iron production and / or crude steel production, in particular comprising carbon-containing gases, for example CO2-containing gases, CO2-containing gases or a combination thereof, a plant for hydrogen production, a chemical plant, wherein the chemical plant is connected to the network pipeline system, a hydrogen pipeline for hydrogen-containing gases, in particular hydrogen, arising during hydrogen production, wherein the hydrogen line is connected to the network pipeline system upstream of the chemical plant in the flow direction, a mixing device for hydrogen-containing gases, in particular hydrogen, arising during hydrogen production and for gases,which arise during pig iron production and / or crude steel production, wherein the mixing device is arranged downstream of the hydrogen production plant and upstream of the chemical plant, in particular connected to the interconnected pipeline system, for mixing gases arising during pig iron production and / or crude steel production with hydrogen-containing gas arising during hydrogen production, in particular hydrogen, for example for adjusting the stoichiometric ratio of the gas composition in the interconnected pipeline system before input into the chemical plant, wherein the blast furnace gas pipeline system is connected to the hydrogen production plant as an input line into the hydrogen production plant and the hydrogen line is connected to the hydrogen production plant as an output line from the hydrogen production plant.
[0016] A further subject of the invention is a method for operating a plant network for steel production, which comprises a blast furnace for pig iron production, a converter steelworks for crude steel production, a blast furnace gas pipeline system for gases arising during pig iron production, a network pipeline system for gases arising during pig iron production and / or
[0017] REPLACEMENT SHEET (RULE 26) crude steel production, in particular comprising carbon-containing gases, for example CO2-containing gases, CO2-containing gases or a combination thereof, a plant for hydrogen production, a chemical plant, wherein the chemical plant is connected to the interconnected pipeline system, a hydrogen pipeline for hydrogen-containing gases, in particular hydrogen, which arise during hydrogen production, wherein the hydrogen line is connected to the interconnected pipeline system upstream of the chemical plant in the flow direction, a mixing device for hydrogen-containing gases, in particular hydrogen, which arise during hydrogen production and for gases which arise during pig iron production and / or crude steel production, wherein the mixing device is arranged downstream of the plant for hydrogen production and upstream of the chemical plant, in particular is connected to the interconnected pipeline system,in particular for mixing gases arising during pig iron production and / or crude steel production with hydrogen-containing gas arising during hydrogen production, in particular hydrogen, for example for adjusting a stoichiometric ratio of the gas composition in the interconnected pipeline system before input into the chemical plant, wherein the blast furnace gas pipeline system is connected to the hydrogen production plant as an input line into the hydrogen production plant and the hydrogen line is connected to the hydrogen production plant as an output line from the hydrogen production plant, wherein the mixing device adjusts a mixed gas, in particular a mixed gas is adjusted with the mixing device,with a stoichiometric mixing coefficient consisting of a dividend with the difference between the molar amounts of hydrogen as the minuend and carbon dioxide as the subtrahend and a divisor with the sum of the molar amounts of carbon monoxide and carbon dioxide.
[0018] The present invention can be implemented in a steel production plant network and in a method for operating a plant network. The devices of the plant network can be present in single and / or multiple versions.
[0019] The steel production plant according to the invention has the advantages over conventional plant combinations that the carbon monoxide contained in the blast furnace gas is converted into hydrogen by means of a water gas shift reaction and that hydrogen or a hydrogen-rich gas can be provided from the steel mill gases for the conversion of carbon-containing gases, for example CO-containing gases, CO2-containing gases or a combination thereof, in the chemical plant and thus without the provision of external
[0020] REPLACEMENT SHEET (RULE 26) Hydrogen, CO and / or CO2 can be chemically bound in larger quantities, and CO2 emissions can be reduced. The material recycling of blast furnace gas and the extraction of hydrogen from it enables more efficient use of blast furnace gas instead of the conventional conversion of blast furnace gas into electricity in a power plant.
[0021] The method according to the invention for operating a plant network has the advantages over conventional methods that, in addition to the production of hydrogen or a synthesis gas for conversion in the chemical plant, CO2 is also separated, which can be converted in the chemical plant and / or otherwise utilized by means of carbon capture and utilization or carbon capture and storage, thus reducing CO2 emissions.
[0022] Detailed description of the invention
[0023] In the chemical plant, chemical products can be produced from the supplied gas streams, each of which contains the components of the final product. Chemical products can be, for example, methanol or higher alcohols or other hydrocarbon compounds. The performance, in particular the output of the chemical plant, is regulated depending on the gas quantities supplied to these plants. A significant challenge for the chemical plant is dynamic operation under changing plant loads, whereby the plant network according to the invention / the method according to the invention for operating the plant network enables stabilization of the operation. Operation under changing plant loads can be realized in particular by the chemical plant having a plurality of small units connected in parallel, which are individually switched on or off depending on the available useful gas flow.For example, different chemical products can be produced in one or more units.
[0024] To produce hydrocarbon compounds, such as methanol or higher alcohols, a gas mixture consisting essentially of CO and / or CO2 and H2 must be provided, which contains the components carbon monoxide and / or carbon dioxide and hydrogen in the correct ratio. Blast furnace top gas and / or converter gas and / or coke oven gas can be used as the hydrogen source, with additional hydrogen being generated by converting the CO content through a water-gas shift reaction. Other hydrogen sources, for example, are also possible, in particular water electrolysis in
[0025] REPLACEMENT SHEET (RULE 26) Consider. Converter gas, for example, can be used to provide CO. Blast furnace top gas and / or converter gas can serve as a CO2 source.
[0026] In the context of the present invention, a plant for hydrogen production is understood to mean a plant for hydrogen production, in particular a plant which provides hydrogen, for example a water-gas shift reaction plant, in particular by converting the CO content by a water-gas shift reaction (CO + H2O <=> CO2 + H2), a plant for hydrogen separation, in particular a hydrogen separation membrane plant or a combination thereof.
[0027] According to a further embodiment of the invention, the plant for hydrogen production is a water-gas shift reaction plant and / or a hydrogen separation membrane plant, in particular the hydrogen separation membrane plant is connected downstream of the water-gas shift reaction plant in the flow direction.
[0028] According to a further embodiment of the invention, the plant for hydrogen production additionally comprises a first plant for CO2 separation, in particular a CO2 scrubber, wherein the first plant for CO2 separation is connected upstream of the hydrogen separation membrane plant in the flow direction, wherein the first plant for CO2 separation is connected to the composite line system by a first CO2 line, in particular the first CO2 line is connected to the composite line system upstream of the mixing device for hydrogen-containing gases in the flow direction.
[0029] In a further embodiment of the invention, the plant network additionally comprises a first CO2 switch for CO2 that is produced in the first plant for CO2 separation, wherein the first CO2 switch is connected to the first CO2 line.
[0030] According to a further embodiment of the invention, the plant network additionally comprises at least one controllable gas distribution device, in particular an operationally controllable gas distribution device for dividing the blast furnace gas flow rates supplied to the blast furnace gas line system and the interconnected line system. In particular, the controllable gas distribution device is arranged between the blast furnace gas line system and the interconnected line system. The blast furnace gas flow rate is preferably distributed by the gas distribution device between the blast furnace gas line system and the interconnected line system.
[0031] REPLACEMENT SHEET (RULE 26) Line system and the interconnected line system, which, after chemical conversion of the gas flow rate of the blast furnace gas line system in the hydrogen production plant and mixing of the generated hydrogen stream or hydrogen-containing stream with the gas flow rate of the interconnected line system in the mixing device, a mixed gas with a stoichiometric mixing coefficient of a dividend with the difference between the molar amounts of hydrogen as the minuend and carbon dioxide as the subtrahend and of a divisor with the sum of the molar amounts of carbon monoxide and carbon dioxide in the range from 1 to 10, preferably in the range from 1.2 to 6, particularly preferably in the range from 1.8 to 4, very particularly preferably in the range from 1.9 to 3 is generated.
[0032] In the context of the present invention, a mixing device is understood to be a device that mixes gases and / or fluids with one another. In particular, a mixing device can be selected from a group consisting of a Venturi nozzle, a mixing vessel, a mixing station, a static mixer, an ejector, a pipeline tee, or a combination thereof.
[0033] According to a further embodiment of the invention, the plant network additionally comprises a coke oven plant, wherein the coke oven plant is connected to the network piping system.
[0034] In a further embodiment of the invention, the plant network additionally comprises a biotechnology plant, wherein the biotechnology plant is connected to the network piping system, in particular downstream of the mixing device for hydrogen-containing gases in the flow direction.
[0035] In the biotechnology plant, biochemical products can be produced from the supplied gas streams, each of which contains the components of the final product.
[0036] In a biotechnology plant, biochemical products can be produced from the supplied gas streams, each of which contains the components of the final product. Biological products can be, for example, alcohols (ethanol, butanol), acetone, or organic acids. In particular, a biotechnology plant is a fermentation plant and, if necessary, a photobiological plant.
[0037] REPLACEMENT LEAF (RULE 26) According to a further embodiment of the invention, the plant network additionally comprises a second plant for CO2 separation, in particular CO2 scrubbing, wherein the blast furnace gas line system is connected to the second plant for CO2 separation as an input line into the second plant for CO2 separation and as an output line from the second plant for CO2 separation, a second CO2 line is connected downstream to the blast furnace gas line system and / or is connected to the network line system, in particular the second CO2 line is connected to the network line system upstream of the mixing device for hydrogen-containing gases in the flow direction.
[0038] According to a further embodiment of the invention, the plant network additionally comprises a second CO2 switch for CO2, which is produced in the second plant for CO2 separation, wherein the second CO2 switch is connected to the second CO2 line.
[0039] In a further embodiment of the invention, the plant network additionally comprises at least one plant for blast furnace gas compression, in particular a blast furnace gas compression plant, wherein the plant for blast furnace gas compression is connected to the blast furnace gas pipeline system.
[0040] According to a further embodiment of the invention, the plant network additionally comprises a plant for blast furnace gas cleaning, in particular a blast furnace gas cleaning plant, wherein the at least one plant for blast furnace gas cleaning is connected to the blast furnace gas pipeline system.
[0041] In the context of the present invention, a blast furnace gas purification plant is understood to mean a plant that at least partially separates those components of the blast furnace gas that could have an adverse effect, particularly with regard to efficiency, in downstream process steps. In particular, blast furnace gas purification is understood to mean single- or multi-stage purification, in particular by mechanical sorting processes such as separation selected from a group based on density, particle size, particle inertia, surface wettability, magnetizability, electrical mobility, by absorptive processes, by catalytic processes, or a combination thereof.
[0042] According to a further embodiment of the invention, the plant network additionally comprises at least one plant for converter gas compression, in particular a converter gas compression plant.
[0043] REPLACEMENT LEAF (RULE 26) In a further embodiment of the invention, the plant network additionally comprises a plant for converter gas cleaning, in particular a converter gas cleaning plant.
[0044] In the context of the present invention, a converter gas purification plant is understood to mean a plant that at least partially separates those components of the converter gas that could have an adverse effect, particularly with regard to efficiency, in downstream process steps. In particular, converter gas purification is understood to mean single- or multi-stage purification, in particular by mechanical sorting processes such as separation selected from a group based on density, particle size, particle inertia, surface wettability, magnetizability, electrical mobility, by absorptive processes, by catalytic processes, or a combination thereof.
[0045] According to a further embodiment of the invention, the mixing device sets a mixed gas with a stoichiometric mixing coefficient from a dividend with the difference between the molar amounts of hydrogen as the minuend and carbon dioxide as the subtrahend and from a divisor with the sum of the molar amounts of carbon monoxide and carbon dioxide in the range from 1 to 10, preferably in the range from 1.2 to 6, particularly preferably in the range from 1.8 to 4, most particularly preferably in the range from 1.9 to 3.
[0046] In a further embodiment of the invention, the plant network additionally comprises a first plant for CO2 separation, in particular CO2 scrubbing, wherein the first plant for CO2 separation is connected upstream of the hydrogen separation membrane plant in the flow direction, wherein the first plant for CO2 separation is connected to the network line system by a first CO2 line, in particular the first CO2 line is connected to the network line system upstream of the mixing device for hydrogen-containing gases in the flow direction, and a first CO2 switch for CO2 that accrues in the first plant for CO2 separation, wherein the first CO2 switch is connected to the first CO2 line and / or a second plant for CO2 separation, in particular CO2 scrubbing,wherein the blast furnace gas piping system is connected to the second CO2 separation plant as an input line into the second CO2 separation plant and as an output line from the second CO2 separation plant, a second CO2 line is connected downstream to the blast furnace gas piping system and / or is connected to the composite piping system, in particular the second CO2 line is connected to the composite piping system upstream of the mixing device for hydrogen-containing gases in the flow direction,
[0047] REPLACEMENT LEAF (RULE 26) and a second CO2 switch for CO2, which accrues in the second plant for CO2 separation, wherein the second CO2 switch is connected to the second CO2 line, wherein with the mixing device and / or the first CO2 switch and / or the second CO2 switch a mixed gas for the chemical plant, in particular mixed gas from the composite line system is set as input into the chemical plant with a molar fraction of the molar amount of CO2 accrued in the mixing device and / or the first CO2 switch and / or the second CO2 switch, in particular separated CO2 gas stream in the range from 5 mol% to 45 mol%, preferably in the range from 8 mol% to 40 mol%, particularly preferably in the range from 15 mol% to 35 mol%, based on the molar amount of CO2 and CO accruing from the blast furnace during pig iron production.
[0048] Short description of the drawings
[0049] The invention is explained below with reference to a drawing which merely represents an exemplary embodiment. It shows schematically
[0050] Fig. 1 is a highly simplified block diagram of a plant network for steel production according to the invention (the elements shown in dashed lines are optional embodiments).
[0051] According to one embodiment of the invention, Fig. 1 shows a steel production plant network 1 comprising a blast furnace 2 for pig iron production, a converter steelworks 3 for crude steel production, a blast furnace gas pipeline system 4 for gases generated during pig iron production, a pipeline system 5 for gases generated during pig iron production and / or crude steel production, a hydrogen production plant 6, and a chemical plant 7. The chemical plant 7 is connected to the pipeline system 5. A hydrogen pipeline 8 for hydrogen-containing gases generated during hydrogen production is connected to the pipeline system 5 upstream of the chemical plant 7.A mixing device 9 for hydrogen-containing gases generated during hydrogen production and for gases generated during pig iron production and / or crude steel production is arranged downstream of the hydrogen production plant 6 and upstream of the chemical plant 7. The blast furnace gas piping system 4 is connected to the hydrogen production plant 6 as an input line to the hydrogen production plant 6, and the hydrogen line 8 is connected to the plant.
[0052] REPLACEMENT SHEET (RULE 26) for hydrogen production 6 as an output line from the hydrogen production plant 6.
[0053] The hydrogen production plant 6 is shown as a water-gas shift reaction plant 10 and a hydrogen separation membrane plant 11, 11'.
[0054] A first CO2 separation system 12 is arranged upstream of the hydrogen separation membrane system 11, 11' in the flow direction, the first CO2 separation system 12 being connected to the composite line system 5 by a first CO2 line 13.
[0055] A first CO2 switch 14 for CO2 produced during the CO2 separation 12 is connected to the first CO2 line 13.
[0056] A controllable gas distribution device 15 for dividing the blast furnace gas flow rates supplied to the blast furnace gas line system 4 and the interconnected line system 5 is arranged between the blast furnace gas line system 4 and the interconnected line system 5. A coke oven system 16 is connected to the interconnected line system 5.
[0057] A biotechnology plant 17 is connected to the interconnected pipeline system 5 downstream of the mixing device 9 for hydrogen-containing gases.
[0058] The blast furnace gas pipeline system 4 is connected to a second CO2 separation plant 18 as an input line into the second CO2 separation plant 18.
[0059] As an output line from the second CO2 separation plant 18, a second CO2 line 19 is connected downstream to the blast furnace gas line system 4 and the interconnected line system 5.
[0060] A second CO2 switch 20 for CO2 produced during the second CO2 separation 19 is connected to the second CO2 line 19.
[0061] A blast furnace gas compression plant 21 is connected to the blast furnace gas pipeline system 4.
[0062] A blast furnace gas cleaning system 22 is connected to the blast furnace gas pipeline system 4.
[0063] A converter gas compression plant 23 and a converter gas cleaning plant 24 are connected to the interconnected pipeline system 5 downstream of the converter steelworks 3 for crude steel production.
[0064] Industrial applicability
[0065] A plant network for steel production and a method for operating a plant network of the type described above can be used in the production of steel.
[0066] REPLACEMENT SHEET (RULE 26) List of reference symbols
[0067] 1 = Plant network
[0068] 2 = blast furnace
[0069] 3 = Converter steelworks
[0070] 4 = Blast furnace gas pipeline system
[0071] 5 = interconnected pipeline system
[0072] 6 = Hydrogen production plant
[0073] 7 = Chemical plant
[0074] 8 = Hydrogen line
[0075] 9 = Mixing device
[0076] 10 = Water-Gas Shift Reaction Plant
[0077] 11, 11' = Hydrogen separation membrane system
[0078] 12 = first CO2 capture plant
[0079] 13 = first CO2 line
[0080] 14 = first CO2 switch
[0081] 15 = controllable gas distribution device
[0082] 16 = Coke oven plant
[0083] 17 = Biotechnology facility
[0084] 18 = second plant for CO2 separation
[0085] 19 = second CO2 line
[0086] 20 = second CO2 switch
[0087] 21 = Blast furnace gas compression plant
[0088] 22 = Blast furnace gas cleaning plant
[0089] 23 = Converter gas compression plant
[0090] 24 = Converter gas cleaning plant
[0091] BFG = blast furnace gas
[0092] KVG = converter gas
[0093] KOG = coke oven gas
[0094] > = essential elements
[0095] > - = optional elements
[0096] > > = Reference line for reference symbols
[0097] REPLACEMENT SHEET (RULE 26)
Claims
Patent claims 1. A plant complex (1) for steel production comprising a blast furnace (2) for pig iron production, a converter steelworks (3) for crude steel production, a blast furnace gas pipeline system (4) for gases generated during pig iron production, a composite pipeline system (5) for gases generated during pig iron production and / or crude steel production, a plant for hydrogen production (6), a chemical plant (7), wherein the chemical plant (7) is connected to the composite pipeline system (5), a hydrogen pipeline (8) for hydrogen-containing gases generated during hydrogen production, wherein the hydrogen pipeline (8) is connected to the composite pipeline system (5) upstream of the chemical plant (7), a mixing device (9) for hydrogen-containing gases generated during hydrogen production and for gases generated during pig iron production and / or crude steel production,wherein the mixing device (9) is arranged downstream of the hydrogen production plant (6) and upstream of the chemical plant (7) in the flow direction, wherein the blast furnace gas line system (4) is connected to the hydrogen production plant (6) as an input line into the hydrogen production plant (6) and the hydrogen line (8) is connected to the hydrogen production plant (6) as an output line from the hydrogen production plant (6)., 2. Plant network (1) according to claim 1, characterized in that the plant for hydrogen production (6) is a water-gas shift reaction plant (10) and / or a hydrogen separation membrane plant (11, 11'), in particular the hydrogen separation membrane plant (11, 11') is connected downstream of the water-gas shift reaction plant (10) in the flow direction.
3. Plant network (1) according to claim 2, characterized in that the plant for hydrogen production (6) additionally comprises a first plant for CO2 separation (12), wherein the first plant for CO2 separation (12) is connected upstream of the hydrogen separation membrane plant (11, 11') in the flow direction, wherein the first plant for CO2 separation (12) is connected to the composite line system (5) by a first CO2 line (13), in particular the first CO2 line (13) is connected to the composite line system (5) upstream of the mixing device (9) for hydrogen-containing gases in the flow direction.
4. Plant network (1) according to claim 3, characterized in that the plant network (1) additionally comprises a first CO2 switch (14) for CO2 that accrues in the first plant for CO2 separation (12), wherein the first CO2 switch (14) is connected to the first CO2 line (13).
5. Plant combination (1) according to one of claims 1 to 4, characterized in that the plant combination (1) additionally comprises at least one controllable gas distribution device (15) for dividing the blast furnace gas flow rates supplied to the blast furnace gas line system (4) and the combined line system (5), in particular the controllable gas distribution device (15) is arranged between the blast furnace gas line system (4) and the combined line system (5).
6. Plant network (1) according to one of claims 1 to 5, characterized in that the plant network (1) additionally comprises a second plant for CO2 separation (18), wherein the blast furnace gas line system (4) is connected to the second plant for CO2 separation (18) as an input line into the second plant for CO2 separation (18) and as an output line from the second plant for CO2 separation (18), a second CO2 line (19) is connected downstream to the blast furnace gas line system (4) and / or is connected to the composite line system (5), in particular the second CO2 line (19) is connected to the composite line system (5) upstream of the mixing device (9) for hydrogen-containing gases in the flow direction.
7. Plant combination (1) according to claim 6, characterized in that the plant combination (1) additionally comprises a second CO2 switch (20) for CO2, which in the second Plant for CO2 separation (19), wherein the second CO2 switch (20) is connected to the second CO2 line (19).
8. A method for operating a steel production plant network (1) comprising a blast furnace (2) for pig iron production, a converter steelworks (3) for crude steel production, a blast furnace gas pipeline system (4) for gases generated during pig iron production, a network pipeline system (5) for gases generated during pig iron production and / or crude steel production, a hydrogen production plant (6), a chemical plant (7), wherein the chemical plant (7) is connected to the network pipeline system (5), a hydrogen pipeline (8) for hydrogen-containing gases generated during hydrogen production, wherein the hydrogen pipeline (8) is connected to the network pipeline system (5) upstream of the chemical plant (7), a mixing device (9) for hydrogen-containing gases generated during hydrogen production and for gases generated during pig iron production and / or crude steel production,wherein the mixing device (9) is arranged downstream of the hydrogen production plant (6) and upstream of the chemical plant (7) in the flow direction, wherein the blast furnace gas piping system (4) is connected to the hydrogen production plant (6) as an input line into the hydrogen production plant (6) and the hydrogen line (8) is connected to the hydrogen production plant (6) as an output line from the hydrogen production plant (6), wherein the mixing device (9) sets a mixed gas with a stoichiometric mixing quotient from a dividend with the difference between the molar amounts of hydrogen as the minuend and carbon dioxide as the subtrahend and from a divisor with the sum of the molar amounts of carbon monoxide and carbon dioxide.
9. The method according to claim 8, characterized in that the mixing device (9) sets a mixed gas with a stoichiometric mixing quotient from a dividend with the difference between the molar amounts of hydrogen as the minuend and carbon dioxide as the subtrahend and from a divisor with the sum of the molar amounts of carbon monoxide and carbon dioxide in the range from 1 to 10, preferably in the range from 1.2 to 6, particularly preferably in the range from 1.8 to 4, most particularly preferably in the range from 1.9 to 3.
10. A method for operating a plant network (1) according to one of claims 8 to 9, wherein the plant network (1) additionally comprises a first CO2 separation plant (12), wherein the first CO2 separation plant (12) is arranged upstream of the hydrogen separation membrane system (11, 11') in the flow direction, wherein the first system for CO2 separation (12) is connected to the composite line system (5) by a first CO2 line (13), in particular the first CO2 line (13) is connected to the interconnected pipeline system (5) upstream of the mixing device (9) for hydrogen-containing gases in the flow direction, and a first CO2 switch (14) for CO2 generated in the first CO2 separation plant (12), wherein the first CO2 switch (14) is connected to the first CO2 line (13) and / or a second CO2 separation plant (18), wherein the blast furnace gas pipeline system (4) is connected to the second CO2 separation plant (18) as an input line into the second CO2 separation plant (18) and as an output line from the second CO2 separation plant (18), a second CO2 line (19) is connected downstream to the blast furnace gas pipeline system (4) and / or is connected to the interconnected pipeline system (5),in particular the second CO2 line (19) is connected to the composite line system (5) in the flow direction upstream of the mixing device (9) for hydrogen-containing gases to the composite line system (5) and a second CO2 switch (20) for CO2, which accrues in the second plant for CO2 separation (19), wherein the second CO2 switch (20) is connected to the second CO2 line (19), characterized in that with the mixing device (9) and / or the first CO2 switch (14) and / or the second CO2 switch (20), a mixed gas for the chemical plant (7) is adjusted with a molar fraction of the molar amount of CO2, in particular separated CO2 gas stream, accrued in the mixing device (9) and / or the first CO2 switch (14) and / or the second CO2 switch (20) in the range of 5 mol-% to 45 mol-%, preferably in the range of 8 mol% to 40 mol%,particularly preferably in the range of 15 mol% to 35 mol% based on the amount of CO2 and CO resulting from the blast furnace (2) during pig iron production,