AT508770A4 - METHOD FOR REMOVING CO2 FROM EXHAUST GASES FROM PLANTS FOR THE PRODUCTION OF REFRIGERATED IRON - Google Patents

Description

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Process for the removal of CO2 from exhaust gases of pig iron production plants 5 For the production of pig iron, which also includes the production of pig iron-like products, there are essentially two known common processes: the blast furnace process and the smelting reduction. 10 The blast furnace process first produces pig iron from iron ore using coke. In addition, scrap can also be used. Thereafter, steel is produced by further processes from pig iron. The iron ore is used as lump, pellets or sinter together with the reducing agents (usually 15 coke, or coal, for example in the form of a

Fine coal indisposition plant) and other constituents (limestone, slag formers, etc.) are mixed to form the so-called Möller and then charged into the blast furnace. The blast furnace is a metallurgical reactor in which the Möllersäule 20 reacts in countercurrent with hot air, the so-called hot blast. By burning the carbon from the coke, the necessary heat for the reaction and carbon monoxide or hydrogen, which is a significant part of the reducing gas and flows through the Möllersäule and reduces the iron ore. 25 The result is pig iron and slag, which are tapped periodically.

In the so-called oxygen blast furnace, which is also referred to as blast furnace with top or top gas recirculation, at 30 the gasification of coke or coal oxygen-containing gas with more than 90% oxygen Fanteil (O2) blown into the blast furnace. For the gas leaving the blast furnace, the so-called top-35 or blast furnace gas, a gas purification must be provided (for example, dust collectors and / or cyclones in combination with wet scrubbers, bag filter units or hot gas filters). • · Q · · · L ·. ·

Furthermore, in the oxygen blast furnace usually a compressor, preferably with aftercooler, provided for the top gas returned to the blast furnace and a device for CO 2 removal, according to the prior art usually by means of 5 pressure swing adsorption.

Further options for the design of a blast furnace process are a heater for the reducing gas and / or a combustion chamber for the partial combustion with oxygen.

The disadvantages of the blast furnace are the demands on the feedstock and the high emission of carbon dioxide. The iron carrier used and the coke must be lumpy and hard 15, so that sufficient cavities remain in the Möllersäule, which ensure the flow through the blown wind. C02 emissions represent a heavy environmental impact. Therefore, there are efforts to replace the blast furnace route. Worth mentioning here are the 20 iron sponge production based on natural gas (MIDREX, HYL, FINMET) and the smelting reduction process (Corex and Finex process).

In smelting reduction, a melter gasifier is used in which hot liquid metal is produced, and at least one reduction reactor in which the carrier of the iron ore (lump, fine ore, pellets, sinter) is reduced with reducing gas, wherein the reducing gas in the melter gasifier by gasification of coal (and optionally a small proportion of coke) with oxygen (90% or more).

Also in the smelting reduction process are usually - gas purification plants (on the one hand for the top gas from the reduction reactor, on the other hand for the reducing gas from the melter gasifier),

a compressor, preferably with an aftercooler, for the reduction gas recirculated into the reduction reactor, a device for CC 2 removal, according to the prior art usually by means of pressure swing adsorption 5, and optionally a heater for the reducing gas and / or a combustion chamber intended for partial combustion with oxygen.

The Corex process is a two-stage 10 smelting reduction process. The smelting reduction combines the process of direct reduction (prereduction of iron into sponge iron) with a melting process (main reduction). 15 The well-known Finex method corresponds to the

Essentially the Corex process, but iron ore is introduced as fine ore.

If CO 2 emissions into the atmosphere are to be reduced in the production of pig iron 20, this must be separated from the exhaust gases from the pig iron production and stored in bound form (English: C02 Capture and Sequestration (CCS)). For the deposition of CO 2, so far mainly the pressure swing adsorption (PSA - Pressure Swing Adsorption), in particular the vacuum pressure swing adsorption (English: VPSA - Vacuum Pressure Swing Adsorption) is used. Pressure swing adsorption is a physical process for the selective separation of gas mixtures under pressure. Specific porous materials (eg, zeolites, activated carbon, activated silica (SiO 2), activated alumina (Al 2 O 3), or the combined use of these materials) are used as a molecular sieve to adsorb molecules 35 according to their adsorption and / or kinetic diameters. The PSA exploits the fact that gases of varying degrees adsorb to surfaces. The gas mixture is introduced into a column under a precisely defined pressure. Now adsorb the unwanted components (here CO2 and H2O) and the recyclable material (here CO, H2, CH4) flows freely through the 5 column. Once the adsorbent is fully loaded, the pressure is released and the column rinsed. To operate a (V) PSA system, electrical power is required for the previous compression of the CO2 rich recycle gas. 10 The product gas stream after pressure swing adsorption, which contains the valuable substances, still contains about 2-6 vol% CO2 in the case of exhaust gases from pig iron production. However, the residual gas stream from the (V) PSA plant still contains relatively high reducing gas constituents (such as CO, H2), which are lost for the production of pig iron.

The residual gas stream after pressure swing adsorption, which contains the undesirable components, is typically composed of exhaust gases from pig iron production as follows: 20

Compound vol% at VPSA vol% at PSA h2 2.2 5.5 n2 1.5 2.4 CO 10.9 16.8 co2 82.1 72.2 CH4 0.7 0.9 h2o 2.6 2, 2 30 The residual gas can not simply be thermally recycled because it would need to be enriched with other fuels due to the low and / or fluctuating calorific value of about ± 50%. It would also calculate the calorific value of the export gas (= that part of the top gas withdrawn from the process of pig iron production)

Reduce pig iron production by mixing it to form the top gas of the blast furnace or the smelting reduction plant, which is reflected in the • r · · · · ·

It also reduces the efficiency of a combined-cycle power plant, such as a combined cycle power plant (CCPP), due to the high fuel gas compression and lower efficiency of the 5 gas turbine. In a steam power plant or boiler, the flame temperature would be reduced during combustion.

If the CO2 from the residual gas is to be bound, the residual gas must be compressed so that the CO2 is in liquid form, and then the liquid CO2 must be placed in a reservoir, to which the pressure usually has to be increased so far that the CO2 is in the liquid-solid or supercritical state where CO2 has a density of about 15,000 kg / m3.

The supercritical state is a state above the critical point in the phase diagram (see FIG. 1) which is characterized by equalizing the densities of liquid and gas phases 20. The differences between the two

Physical states stop existing at this point.

Such a high compression requires the use of a high performance multi-stage compressor to bring the 25 typical densities at line level ranging from greater than 0 ° C to greater than 70 bar (7,000,000 Pa), more preferably 80%. 150 bar at ambient temperatures, is located. 30 However, the residual gas from a (V) PSA is not suitable for being bound because it has a relatively high proportion of CO, H2, N2, CH4, etc. besides CO2. On the one hand, the CO content poses a safety risk since it can lead to ignition or explosion in the event of a leakage to the risk of persons (CO poisoning) and under certain circumstances. Furthermore, the "impurities" CO, H2, ... of the CO2 are lost for the reduction work and influence the physical

Characteristics of the compressed gas, for which due to fluctuating levels of CO, H2, etc., the measurability, the compression, the water solubility and the transport properties also vary. 5

Contaminants must also reduce the distances between stations where the transported gas mixture or fluid must be recompressed, increasing investment and operating costs due to additional compressors or pumps and their energy requirements. Or, the inlet pressure in the line must be increased to reduce the number or power of the additional pumps and compressors along the line. 15 studies on the influence of impurities on the transport of liquefied gases has been carried out by Newcastle University and published at http://www.geos.ed.ac.uk/ccs/UKCCSC/Newcastle 2 07.ppt and is shown in FIG. 2 shown. 20

It is therefore an object of the invention to separate CO 2 from exhaust gases of pig iron production to a greater extent than (V) PSA from other gases, but in addition to use a lower energy source than (V) PSA. 25

The object is achieved by a method according to claim 1, wherein the CO 2 is removed by means of chemical absorption, wherein the heat for the regeneration of the absorbent is at least partially 30 - provided either by low-pressure steam from a steam turbine of a steam power plant and / or a steam turbine for the use of waste heat from the production of pig iron (reducing gases, top gases, etc.) is used 35 and / or by low pressure steam from a waste heat boiler of a steam power plant and / or from a waste heat boiler for the use of waste heat from the pig iron production.

Under "low pressure steam" Steam is understood as being saturated and having a pressure between 2 and 10 barg. 5 By the term "steam power plant" fall on the one hand conventional steam power plants, where thermal energy is generated by combustion of fuels, is made with the steam, which is utilized in a steam turbine, that is ultimately converted into electrical energy.

On the other hand, it also includes a combined cycle power plant, more specifically a combined cycle power plant (CCPP), in which the principles of a gas turbine power plant and a steam power plant are combined. A gas turbine serves as a heat source for a downstream waste heat boiler, which in turn acts as a steam generator for the steam turbine. ÜÜ

By using a chemical absorption process 20, the CO, H 2, CH 4 fraction recovered from the pig iron production can be increased over a (V) PSA and the CO 2 fraction in the product gas can be substantially reduced (up to a few ppmv). 25 The use of low-pressure steam from an existing steam process is less expensive than the production of steam with its own aggregate for desorption only. In addition, the use of a low-value energy source such as steam from an economic and ecological point of view is preferable to a high-quality energy source such as electricity. The removal of steam from a running steam power plant is also more flexible than from a specially designed for CO2 removal steam generator, the fuel for steam generation is better utilized in a continuous steam process 35. • · · • ·

The residual gas stream after chemical absorption mainly contains CO 2 and after removal of H 2 S only more traces of H 2 S and can therefore be released directly into the atmosphere and / or just fed to CO 2 compression followed by CO 2 storage (sequestration). eg EOR - enhanced oil recovery) and / or as a substitute for N2 in iron production: the residual gas stream consists mainly of CO 2 and can therefore be used for 10 charging equipment, barrier seals and selected flushing and cooling gas consumers ,

Due to the low level of impurities, the energy required to compress the residual gas stream from the chemical absorption to the liquid-solid or supercritical state (> 73.3 bar) is about 20-30% lower than for residual gas from a (V) PSA. Consequently, the distances between the stations increase in the gas lines, where the gas must be re-compressed. Both the acquisition costs and the operating costs for CO 2 storage are thereby reduced.

Compared to pressure swing adsorption, the chemical absorption operates with lower pressures for the gas to be purified and a lower pressure drop for the

Removal of CO2, so that energy is saved here too. Unlike a VPSA, no vacuum compressors are needed, which also consume a lot of energy and cause high maintenance costs. The low energy consumption is an advantage especially for those countries where energy is scarce and / or expensive.

Due to the now higher proportion of combustible materials in accordance with the invention purified exhaust gas of pig iron production, the system performance can be increased or their specific consumption values can be lowered or it can also in the 35

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Combustion of this gas in a power plant a higher efficiency of the power plant can be realized.

The investment costs for a chemical absorption process are comparable to those for a VPSA plant. But the absorption process needs large amounts of low-pressure steam with a pressure of more than 2 barg or higher, e.g. 10 barg. This steam would be expensive if it had to be manufactured separately and could not be taken from a 10 existing steam source.

There are various chemical absorption methods suitable for this invention: A first absorption method is characterized by the use of potassium carbonate as the absorbent. Hot Potassium Carbonate (HPC) or " Hot Pot " is used. Depending on the provider of this process, various substances are added to the potassium carbonate: activators which are to increase the CC> 2 deposition and inhibitors which are said to reduce the corrosion. A widely used method of this type is known as the Benfield method and is offered by UOP. The Benfield process requires approximately 0.75 kg of steam 25 per Nm3 of gas to be purified.

A second absorption process is known as amine scrubbing with several sub-processes. In a first step, slightly alkaline aqueous solutions of amines 30 (mostly ethanolamine derivatives) are used, which are the acidic ones

Reversibly chemically absorbing gases, such as CO2. In a second process step, the acidic gas is thermally separated (by heating) from the amine and the recovered amine is used again for washing.

Known methods for this are the Amine Guard FS method of UOP, which provides a reduction of the C02 content to 50 ppmv and 35 αο of the HaS content to 1 ppmv. The steam requirement of this process is about 1.05 kg of steam per Nm3 of gas to be purified.

Amines, such as diethanolamine (DEA), are also used as activators 5 for absorption processes using potassium carbonate, such as for the Benfield process. For amine scrubbing primary amines can be used, such as methylamine, monoethanolamine (MEA) and / or diglycolamine 10 (DGÄ). For amine scrubbing, secondary or secondary amines may be used in addition to or as an alternative to primary amines, such as diethanolamine (DEA) and / or diisopropanolamine (DIPA). 15

In addition or as an alternative to primary and / or secondary amines, it is also possible to use tertiary amines, for example triethanolamine (TEA) and / or methyldiethanolamine (MDEA). An existing method for this is the aMDEA method of the company BASF (offered by Linde and Lurgi), which uses activated methyldiethanolamine (MDEA). The steam requirement of this process is about 0.85 kg of steam per Nm3 of gas to be purified. With the process according to the invention, top gas from a blast furnace, in particular from an oxygen blast furnace with top gas recirculation, which is operated predominantly with oxygen instead of hot blast, can be purified of CO 2. 30

The method according to the invention is best used for exhaust gas from smelting reduction plants for CU2 purification of at least one of the following exhaust gases: exhaust gas (so-called excess gas) from a melter gasifier, exhaust gas from at least one reduction reactor, exhaust gas (so-called top gas) from at least one .. · * 1ϊ

Fixed bed reactor for preheating and / or reducing iron oxides and / or iron briquettes.

In order to make better use of the reducing components of the gas after the removal of CO2 for the production of pig iron, it can be provided that at least a part of the purified exhaust gas is used again as a reducing gas for the production of pig iron. 10 In order to obtain low-pressure steam simply, it is best taken from the steam turbine or the waste-heat boiler of the steam turbine at the end of the expansion.

In a device according to the invention corresponding to the method according to the invention, a system for removing CO2 by means of chemical absorption is provided, wherein the plant part for the regeneration of the absorbent - either connected to a steam turbine of a steam power plant or a steam turbine for using the waste heat from the pig iron production that Low-pressure steam from the steam turbine can be passed at least partially into the plant part for regeneration of the absorbent, and / or is connected to the waste heat boiler of a steam power plant and / or the waste heat boiler for the use of waste heat from the production of pig iron, that the waste heat at least partially for generating of low pressure steam can be used to regenerate the absorbent.

In particular, a line 30 can be provided for the blast furnace process, with which top gas from a blast furnace, in particular from an oxygen blast furnace with Topgasrückführung, can be fed into the plant for the removal of CO 2 by means of chemical absorption. In a smelting reduction process, at least one line would then be provided with which exhaust gas from a smelting reduction plant can be conducted into the plant for the removal of CO 2 by means of chemical absorption.

At least one of these lines can be connected to at least one of the following 5 devices: with a melter gasifier, with one or more reduction reactors, with a fixed bed reactor for preheating and / or reducing iron oxides and / or iron briquettes. 10

A further embodiment consists in that a line is provided, with which at least a part of the purified exhaust gas can be redirected back to the pig iron production as reducing gas. 15

For introducing low-pressure steam into the system for removing CO.sub.2, it may be provided that it is connected to the low-pressure part of the steam turbine and / or the waste-heat boiler. 20

The invention is explained in more detail below with reference to the exemplary and schematic figures.

Fig. 1 shows a phase diagram of CO2. 25 Fig. 2 shows the relationship between impurities of gases and the compaction stations necessary for the transport of liquefied gases.

Fig. 3 shows the connection according to the invention between a blast furnace and two power plants. Fig. 4 shows the connection according to the invention between a plant for smelting reduction and two power plants.

FIG. 1 shows a phase diagram of CO2. On the horizontal axis the temperature is plotted in K, on the vertical axis the pressure in bar (1 bar = 105 Pascal). The individual aggregate states (solid or solid, * 43 • ♦ ·· · • · ·

Liquid or liquid and gas or gaseous) are separated by lines.

The triple point is the point where solid, liquid and gaseous phases meet. 5 The supercritical state (supercritical fluid) is a state above the critical point in the phase diagram, which is characterized by the equalization of the densities of the liquid and gas phases. The differences between the two states of aggregation cease to exist at this point. 10

In Fig. 2, the relationship between impurities of gases and the compaction stations necessary for the transport of liquefied gases is shown.

On the horizontal axis the impurities are plotted in% of the gas volume, on the vertical axis the distance between the compressor stations in km. For each contamination, a separate curve is drawn. At 10% contamination (right margin of illustration), the least effect on the distance of the 20 compressor stations in H2S, followed by S02, CH4, Ar, 02, N2 and CO is the same, then N02, the greatest influence is H2, where the Curve almost goes to zero.

In Fig. 3, an oxygen blast furnace with top gas recirculation 1 25 is shown, in which iron ore from a sinter plant 2 and coke (not shown) is supplied. Oxygen-containing gas 3 having an oxygen content > 80% is introduced into the ring line 4, as well as in the reduction gas furnace 6 heated reducing gas 5 is introduced together with 30 cold or preheated oxygen 02 in the blast furnace 1. Slag 7 and pig iron 8 are withdrawn below. At the top of the blast furnace 1, the top or top gas 9 is removed and pre-cleaned in a dust separator or cyclone 10 and a wet scrubber 11 (or a bag filter or filter system) again cleaned. The purified top or top gas can on the one hand taken directly as export gas 12 from the blast furnace system and a

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Exporting gas container 13 are supplied, on the other hand, it can be fed to a system 14 for the chemical absorption of CO2, wherein the purified top or blast furnace previously compressed in a compressor 15 to about 2-6 barg and in a 5 aftercooler 16 to about 30-60 ° C is cooled.

The system 14 for the chemical absorption of CO2 consists essentially of an absorber 17 and a stripper 18. Such systems are known from the prior art and will therefore be described here only in outline form. In the absorber 17, the top or top gas 9 to be cleaned is introduced from below, while from above a solution absorbing the acidic components of the gas, such as an amine solution, flows downwards. Here the CO2 is removed from the top or top gas and the cleaned gas is returned to the blast furnace 1.

The loaded absorbent (the absorbent liquid) is passed from above into the stripper 18, where it is at> 100 ° C., in particular with warm low-pressure steam 19, which has a temperature of approximately 120-260 ° C., especially 150 ° C. 110-120 ° C, is heated, whereby the acidic gases, in particular the CO2, are released again as residual gas 20. The residual gas 20 can either be released into the atmosphere again after an H2S purification 21 and / or fed to another compressor 22 for the liquefaction of CO.sub.2, in order to be forwarded and stored approximately underground, or as a substitute for nitrogen in the To use iron production.

The resulting in the stripper condensate 23 is withdrawn and 30 can be fed to the steam cycle of a steam power plant 32.

The export gas from an optional export gas container 13 can be fed to a combined cycle power plant 24 as fuel, optionally via a buffer memory 25 and a filter 26. The export gas is supplied in a gas compressor 27 and the gas turbine 28. The waste heat from the gas turbine becomes • * 45

used in the waste heat boiler 29 for a steam cycle with a steam turbine 30. Also from this steam turbine 30 low pressure steam for the stripper 18 could be removed (not shown). 5

Alternatively or in addition to the combined cycle power plant 24, the export gas 12 - may be supplied via a further export gas container 31 and the steam boiler 33 of a steam power plant 32 as fuel. From the 10 or the last stages of the steam turbine 34 of the

Steam power plant 32 is withdrawn low-pressure steam 19 and fed to the stripper 18.

The pressure energy content of the export gas 12 can also be utilized in a top gas pressure recovery turbine 35, which in this example is arranged between the export gas container 13 and the further export gas container 31. 20 Neither the combined cycle power plant 24 nor the steam power plant 32 required export gas 12 can be used for other purposes, such as for drying raw materials (coal, fine coal or ore drying) 36. 25

Fig. 4 shows the connection according to the invention between a plant for smelting reduction and two power plants, namely a combined cycle power plant 24, which is constructed exactly the same as that in Fig. 3, and a steam power plant 32, also with 30 same structure as that in Fig. 3rd Also in Fig. 4, either only the combined cycle power plant 24 or only the steam power plant 32 may be provided or both the combined cycle power plant 24 and the steam power plant 32. The two power plants 24, 32 are supplied by a Finex plant with export gas 12, which in an export gas container 13 or 31 can be cached. An optional '· ♦ * * · ΐδ · «·· · • • • ·

Expansion turbine 35 is again the utilization of the energy contained in the export gas 12. Not required for the power plants 24, 32 export gas 12 can be supplied to a raw material drying 36 again. 5

The Finex plant has in this example four reduction reactors 37-40, which are designed as fluidized bed reactors and are charged with fine ore. Fine ore and additives 41 are fed to the ore drying 42 and from there first to the fourth

Reactor 37, they then enter the third 38, the second 39 and finally the first reduction reactor 40. Instead of four fluidized bed reactors 37-40 but only three may be present. 15

In countercurrent to the fine ore, the reducing gas 43 is guided. It is introduced at the bottom of the first reduction reactor 40 and exits at its top. Before it enters the second reduction reactor 39 from below, it can still be heated with oxygen O 2, as well as between the second 39 and third reduction reactor. The heat of the exhaust gas 44 from the reduction reactors 37-40 is used in a waste heat boiler 45 for generating steam, the resulting low-pressure steam 46 is supplied to the stripper 18 of the plant for the chemical absorption of CO2.

The exiting from the waste heat boiler 45 exhaust 44 is cleaned in a wet scrubber 47 and used as export gas 12 as described above in downstream power plants on. A partial flow of the exhaust gas 44 is - according to the invention - 30 supplied to the absorber 17 for CO 2 removal.

The reducing gas 43 is produced in a melter gasifier 48, in which on the one hand coal in the form of lumpy coal 49 and coal in powder form 50 - this together with 35 oxygen O2 - is fed, in the other hand, in the reduction reactors 37-40 vorreduzierte and in of iron briquetting 51 in hot condition to briquettes (English: • • • * ·· ·· 4 · 44 • • • • • • • • • • • • • • • • • • • • * # 4 4 • • • • • • 7 * • • 4 ·· · HCl Hot Compacted Iron) shaped iron ore is added. The iron briquettes arrive via a conveyor 52 in a storage tank 53, which is designed as a fixed bed reactor, where the iron briquettes are coarsely cleaned with 5 generator gas 54 from the melter gasifier 48 optionally preheated and reduced. Cold iron briquettes 63 can also be added here. Subsequently, the iron briquettes or oxides are charged from above into the melter gasifier 48. Low reduced iron (LRI = low reduced iron) may also be withdrawn from the iron briquetting 51.

The coal in the melter gasifier 48 is gasified, it creates a gas mixture consisting mainly of CO and H2, and 15 deducted as a reducing gas (generator gas) 54 and a

Partial flow as reducing gas 43 the reduction reactors 37-40 is fed.

The hot metal molten in the melter gasifier 48 and the slag are withdrawn, see arrow 56.

The top gas 54 withdrawn from the melter gasifier 48 is first passed into a separator 57 to deposit with discharged dust and to return the dust to the melter gasifier 48 via dust burners.

A portion of the purified top gas from the coarse dust is further purified by wet scrubber 58 and removed as excess gas 59 from the Finex plant and - according to the invention - the absorber 17 of the system 14 for the chemical absorption of CO2 30 fed.

Another part of the purified generator gas 54 is also further purified in a wet scrubber 60, fed to a gas compressor 61 for cooling and then after mixing with the extracted from the absorber 17, freed from CO2 35 product gas 62 back to the generator gas 54 after the melter gasifier 48 for cooling fed. By this recycling of the C02-freed gas 62, the therein

The reduced proportions still contained in the finex process can still be utilized and, on the other hand, the required cooling of the hot generator gas 54 can be from about 1050 ° C. to 700-870 ° C. be ensured. 5

The top gas 55 leaving the storage system 53, where the iron briquettes or iron oxides are heated and reduced with dedusted and cooled generator gas 54 from the melter gasifier 48, is cleaned 10 in a wet scrubber 64 and then likewise fed to the absorber 17 for removal of CO 2.

The stripper 18 can on the one hand low-pressure steam 46 from the waste heat boiler 45 and / or low-pressure steam 19 from the steam turbine 30 of the combined cycle power plant 24 and / or

Low-pressure steam from the steam turbine 34 of the steam power plant 32 are supplied. Preferably, the waste heat from the iron-making process should be used because of the short distances between the waste heat boiler and plant 14 for chemical absorption of CO 2.

The condensate 23 of the stripper 18 is supplied to the steam cycle of the steam power plant 32 in this example. But it can also be fed to the waste heat boiler or the combined cycle power plant 25.

The residual gas 20 downstream of the stripper 18 can be released into the atmosphere again in whole or in part after H2S purification 21 or can be completely or partially fed to a CO 2 storage after compression by means of compressor 22. 30

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REFERENCE SIGNS LIST 1 5 2 3 4 5 6 10 7 8 9 10 11 15 12 13 14 15 16 20 17 18 19 20 21 25 22 23 24 25 26 30 27 28 29 30 31 35 32 33 34

Blast furnace sintering plant oxygen-containing gas ring pipe hot blast

Reducing gas oven

slag

pig-iron

Top or top gas

Dust collector or cyclone

wet scrubbers

export gas

Export gas container

Plant for chemical absorption of C02

compressor

aftercooler

absorber

stripper

Low pressure steam residual gas after stripper 18 H2S cleaning

Compressor for the liquefaction of C02

condensate

Combined cycle power plant

buffer memory

filter

gas compressor

gas turbine

waste heat boiler

Steam turbine further export gas container

Steam power plant

steam boiler

Steam turbine of the steam power plant 32 5 10 15 20 25

35 Expansion turbine 36 For raw material drying (charcoal, fine coal or ore drying) 37 Fourth reduction reactor 38 Third reduction reactor 39 Second reduction reactor 40 First reduction reactor 41 Fine ore and additives 42 Ore drying 43 Reduction gas 44 Exhaust gas from reduction reactors 37-40 45 Waste heat boiler 46 Low pressure steam from waste heat boiler 45 47 Wet scrubber for exhaust gas 44 48 Fumed carburetor 49 Lumpy coal 50 Coal in powder form 51 Iron briquetting 52 Conveyor 53 as a fixed bed reactor designed storage tank for preheating and reducing iron oxides and / or iron briquettes 54 Top or generator gas from melter gasifier 48 55 Top gas from wet scrubber 64 56 Hot metal and slag 57 Fine ore separator 58 Wet scrubber 59 Excess gas 60 Wet scrubber 61 Gas compressor 62 Gas released from C02 (product gas) from absorber 17 63 Cold iron briquettes 64 Wet scrubber 30

Claims (6)

5 10 15 20 25 claims A process for the removal of CO2 from exhaust gases (12, 44, 55, 59) of pig iron production plants, characterized in that the CO2 is removed by means of chemical absorption (14), the heat for the regeneration of the absorbent being at least partly - either by Low pressure steam (19) is provided, which is from a steam turbine (30, 34) of a steam power plant (24, 32) and / or a steam turbine for use of waste heat from the pig iron production is used, - and / or by low-pressure steam (46) a waste heat boiler of a steam power plant and / or from a waste heat boiler (45) for using the heat from the pig iron production. 2. The method according to claim 1, characterized in that is used as an absorbent potassium carbonate. 3. The method according to claim 1 or 2, characterized in that it comprises an amine wash. 4. The method according to claim 3, characterized in that primary amines, such as methylamine, monoethanolamine (MEA) and / or diglycolamine (DGA) are used. 5. A process as claimed in claim 3 or 4, characterized in that secondary amines, such as diethanolamine, are used to prepare secondary amines, such as diethanolamine. · · (DEA) and / or diisopropanolamine (DIPA). 6. The method of claim 3, 4 or 5, characterized in that tertiary amines, such as triethanolamine 5 (TEA) and / or methyldiethanolamine (MDEA) are used. 7. The method according to any one of claims 1 to 6, characterized in that top gas from a blast furnace, in particular from an oxygen blast furnace (1) is cleaned with 10 Topgasrückführung, from the CO2. 8. The method according to any one of claims 1 to 7, characterized in that the exhaust gas (44, 55, 59) is purified from a smelting reduction plant. 9. The method according to claim 8, characterized in that at least one of the following exhaust gases is cleaned: exhaust gas (59) from a melter gasifier (48), exhaust gas (44) from at least one reduction reactor (37-40), exhaust gas ( 55) from at least one fixed bed reactor (53) 20 for preheating and / or reduction of iron oxides and / or iron briquettes. 10. The method according to any one of claims 1 to 9, characterized in that at least a portion of the CO2 purified from the exhaust gas (62) is used again as a reducing gas for pig iron production. 25 • · w »*» * * * »* w • · · 9 · · · · · · · · rr ^ · · · · · 11. The method according to any one of claims 1 to 10, characterized in that low-pressure steam at the end of the expansion of the steam turbine (30, 34) is removed. 5 12. The method according to any one of claims 1 to 11, characterized in that the recovered CO2 rich gas from the CO 2 removal process is used as a substitute gas in the iron production process and / or for the treatment and storage of CO2. 10 13. A device for carrying out the method according to one of claims 1 to 12, characterized in that a plant (14) is provided for the removal of CO2 by means of chemical absorption, wherein the plant part (17) for the regeneration of the absorbent 15 - either so with a Steam turbine (34) of a steam power plant (32) or a steam turbine (30) for using the waste heat from the pig iron production is connected, that low-pressure steam from the steam turbine (30, 34) at least partially in the plant part (17) can be passed to regenerate the absorbent , - And / or so with the waste heat boiler (33) of a steam power plant and / or the waste heat boiler (29) is connected to use the waste heat from the pig iron production that the low pressure steam at least 20 can be used in part for the regeneration of the absorbent. 14. The device according to claim 13, characterized in that a line is provided, with which top gas (12) from a blast furnace, in particular from an oxygen blast furnace (1) with Topgasrückführung, passed in the system (14) for the removal of CO2 by means of chemical absorption can be. 15. The apparatus according to claim 13, characterized in that at least one conduit is provided, with which exhaust gas (44, 55, 59) can be passed from a smelting reduction plant in the system (14) for the removal of CO2 by means of chemical absorption. 16. The device according to claim 15, characterized in that at least one of these lines is connected to at least one of the following devices: - with a melter gasifier (48), - with one or more reduction reactors (37-40), - with a fixed bed reactor (53 ) for preheating and / or reducing iron oxides and / or iron briquettes. 17. Device according to one of claims 13 to 16, characterized in that a line is provided, with which at least a part (62) of the purified exhaust gas can be routed back to the pig iron production again as a reducing gas. 18. Device according to one of claims 13 to 17, characterized in that for introducing low-pressure steam into the system for the removal of CO2, this is connected to the low pressure part of the steam turbine (30, 34) and / or to the waste heat boiler. 19. Device according to one of claims 13 to 18, characterized in that the system (14) for the removal of CO2 by means of chemical absorption is connected to a plant for pig iron production and / or a plant for processing and storage of CO2, that the obtained C02 rich gas can be used as a substitute gas in the iron production process and / or for the treatment and storage of CO2.