RU125879U1 - DEVICE FOR THE REMOVAL OF CO2 FROM EXHAUST GASES DEVICES FOR THE PRODUCTION OF IRON - Google Patents

Abstract

1. A device for removing CO from the exhaust gases (12, 44, 55, 59) of devices for the production of cast iron, in which a device (14) for removing CO is provided by chemical absorption, wherein steam is used to regenerate the absorbent, characterized in that a part of the device ( 17) for regeneration of absorbent material - so connected to a steam turbine (30) for using waste heat in the production of pig iron and, if necessary, additionally to a steam turbine (34) of a steam turbine power station (32), that low-pressure steam from a steam turbine (30, 34) can can be sent, at least partially, to a part of the absorbent recovery device (17), and / or is connected to a recovery boiler (29) for using the waste heat in the production of pig iron and, if necessary, additionally to a recovery boiler (33) of a steam turbine power plant that low pressure steam can be used at least partially for the regeneration of the absorbent, and moreover, at least one pipeline from the group is provided: - a pipeline through which the exhaust gas (12) can be directed from the blast furnace to a private from an oxygen blast furnace (1) with exhaust gas recirculation to a device (14) for CO removal by chemical absorption, a pipeline through which exhaust gas (44, 55, 59) can be sent from the recovery device to the removal device (14) CO by chemical absorption. 2. The device according to claim 1, characterized in that at least one of the said pipelines is connected to at least one of the following devices: - with a melting gasifier (48), - with one or more reduction reactors (37-40), - with a reactor

Description

For the production of cast iron, which also includes the production of products similar to cast iron, there are essentially two well-known traditional processes: blast furnace and smelting reduction. In a blast furnace process, cast iron is first produced from iron ore using coke. In addition, iron scrap can be additionally used. Then, through additional processes, steel is produced from cast iron. Iron ore in the form of lump ore, pellets or agglomerate is mixed together with reducing agents (in most cases, coke or also coal, for example, in the form of coal fines) and other components (limestone, slag-forming, etc.) into the so-called galosh and then loaded into a blast furnace. A blast furnace is a metallurgical reactor in which, in countercurrent flow, the charge column reacts with hot air, the so-called hot blast. Due to the combustion of carbon from coke, the heat and carbon monoxide or hydrogen necessary for the reaction arise, representing a significant part of the reducing gas, flowing through the charge column and reducing iron ore. As a result, pig iron and slag are formed, which are periodically released through the tap hole.

In the so-called oxygen blast furnace, also called blast furnace gas recirculation furnace (top gas or blast furnace gas), when gasifying coke or coal, oxygen-containing gases containing more than 90% oxygen (O ₂ ) are blown into the blast furnace.

For blast furnace gas coming out of the blast furnace, here referred to as top gas or blast furnace gas, gas purification must be provided (for example, a dust collector and / or cyclone in combination with a wet scrubber, bag filter or hot gas gas filter). In addition, in a blast furnace an oxygen furnace is provided, as a rule, with a compressor mainly with an additional cooler for blast furnace gases (top gases) returned to the blast furnace, as well as a device for extracting CO ₂ from the prior art in most cases by absorption under pressure.

Other possibilities for carrying out the blast furnace process are a reducing gas heater and / or a combustion chamber for partial combustion with oxygen.

The disadvantages of the blast furnace are the requirements for feedstock and a high level of carbon dioxide emissions. The sources of iron and coke used must be agglomerated and solid, so that sufficient voids are retained in the charge column, ensuring flow during air purging. CO ₂ emissions are a strong environmental pollutant. Therefore, efforts are being made to change the path of the blast furnace. It is worth mentioning here the production of sponge iron based on natural gas (MIDREX, HYL, FINMET), as well as the reduction smelting method (Sogeh and Finex methods).

In reduction smelting, a melting gasifier is used in which hot liquid metal is produced, as well as at least one reduction reactor, in which the iron ore carrier (lump ore, ore fines, pellets, sinter) is reduced with a reducing gas, and a reducing gas is produced in the melter gasifier, the gasification of coal (and, if necessary, small particles of coke) with oxygen (90% or more).

Also, in the fusion reduction process,

- gas purification devices (on the one hand, for top gas from a reduction reactor, on the other hand, for reducing gas from a melting gasifier),

- a compressor, mainly with an additional cooler for returning the recovery gas to the recovery reactor,

- a device for removing CO ₂ , according to the prior art in most cases by adsorption with a differential pressure,

and, if necessary, a heater for reducing gas, and / or a combustion chamber for partial combustion with oxygen.

Sogeh-process is a two-stage method of smelting reduction. Recovery smelting combines the direct reduction process (preliminary reduction of iron to sponge iron) with the smelting process (basic reduction). The Finex process also known is essentially the Sogeh process, but iron ore is used as ore fines.

In order to reduce emissions of CO ₂ into the atmosphere during the production of pig iron, it should be recovered from the flue gas from pig iron production and accumulated in a bound form (English: CO ₂ Capture and Sequestration (CCS)). Differential pressure absorption (PSA-Pressure Swing Adsorption), in particular also vacuum pressure adsorption (VPSA - Vacuum Pressure Swing Adsorption), is still mainly used to capture CO ₂ . Differential pressure adsorption is a physical process for the selective separation of gas mixtures under pressure. Special porous materials (e.g. zeolite, activated carbon, activated silica (SiO ₂ ), activated alumina (A1 g0z) or a combination of these materials) are used as molecular sieves to adsorb molecules in accordance with their adsorption strength and / or its kinetic diameter. In PSA, the ability of gases with different strengths to adsorb to the surface is used. The gas mixture is introduced into the column under a precisely defined pressure. Unwanted components (here CO ₂ and H ₂ O) are adsorbed and valuable material (here CO, H ₂ , CH ₄ ) is adsorbed freely through the column. Once the adsorbent is fully charged, the pressure is reduced and the column is washed. To operate 'VPSA devices, an electric current is required to preconcentrate the CO ₂ enriched return gases.

The gas product stream after adsorption with a pressure differential, which contains valuable materials, contains another 2-6 vol.% CO ₂ in the exhaust gases from pig iron production. However, the residual gas flow from the PSA devices (V) still contains relatively high amounts of reducing gas (e.g., CO, H ₂ ) that are lost to produce iron.

The residual gas stream after adsorption with a differential pressure, which contains undesirable components, consists of the following exhaust gases in the production of iron by the usual method:

Compound vol.% with VPSA vol.% with PSA H ₂ 2.2 5.5 N ₂ 1,5 2,4 With 10.9 16.8 CO ₂ 82.1 72,2 CH ₄ 0.7 0.9 H ₂ O 2.6 2.2

The residual gas cannot simply be thermally used until, due to the low and / or inconsistent calorific value "of approximately ± 50%, it is not enriched for this with other fuels. The calorific value of the export gases (that part of the top gases that are removed from of cast iron production) from the cast iron production process is reduced if it is mixed with the top gas of a blast furnace or a reduction smelting device, as a result of which the efficiency of the power plant supplied with export gas is also reduced, in the case of combined th power (Engl .:

combined cycle power plant, shortly SSRP) due to the high compression of combustible gas and low-efficiency gas turbines. At a steam turbine power plant or heating boiler, the flame temperature during combustion is reduced.

When CO ₂ from the residual gas should be bound, the residual gas must be compressed so that CO _{2 is} in liquid form, and then liquid CO ₂ must be delivered to its location, for

which, in most cases, the pressure should increase, so that CO ₂ was in a liquid-solid or supercritical state, where CO ₂ has a density of about 1000 kg / m ³ .

The supercritical state is a state above the critical point in the phase diagram (see Fig. 1), which differs in the equalization of the densities of the liquid and gas phases. Differences between both aggregative states at this point cease to exist.

For such a high seal, a high-performance multi-stage compressor should be used to bring the usual densities to a trunk level that is in the region of more than about 0 ° C and more than 70 bar (7000000 Pa), preferably 80-150 bar at ambient temperature.

However, the residual gas from (V) PSA is not suitable to be bound since it has, along with CO _{2, a} relatively high content of CO, H ₂ , N ₂ , CH ₄ , etc. On the one hand, the content of carbon monoxide presents a potential safety risk, since it can lead to a danger to people (leakage of carbon monoxide) and, in certain circumstances, ignition or explosion if leaks occur. Further, “impurities” of CO ₂ , such as CO, H ₂ ..., act on the loss of reducing ability and affect the physical properties of the compressed gas due to the inconsistent content of CO, H ₂ , etc., measurability, compressibility, water solubility and transportability also change.

Due to impurities, the distance between the devices where the transported gas mixture or the transported liquid must be re-compressed must be reduced, so that investment and production costs are increased due to additional compressors or pumps and their energy demand. Or the inlet pressure to the line must be increased to reduce the number or capacity of additional pumps and compressors along the line.

The University of Newcastle conducted research on the effect of pollution on the transportation of liquefied gases and published at http://www.geos.ed.ac.uk/ccs/UKCCSC/Newcastle 2 07.ppt, presented in figure 2.

Therefore, the task is to separate CO ₂ from other gases from the waste gases of pig iron production in large quantities by the (V) PSA method, and use for this purpose additional valuable other energy-efficient sources of energy as with (V) PSA.

To solve this problem, there are known devices that provide the removal of CO ₂ from the exhaust gases of devices for the production of pig iron by chemical absorption, for example WO 2004/052510 A1, 06.24.2004, FR 2874683, 03.03.2006 and EP 1967249, 09/10/2008. The closest solution to the purpose is WO 2004/052510 A1, June 24, 2004, in which a device is disclosed for removing CO ₂ from the exhaust gases of pig iron production devices by chemical absorption, and steam is used to regenerate the absorbent. The known solution is characterized by high equipment costs.

To solve the problem and eliminate the disadvantages of the prior art, a device for removing CO ₂ from the exhaust gases of cast iron production devices is proposed, in which a device for removing CO ₂ by chemical absorption is provided, while steam is used to regenerate the absorbent, characterized in that a part absorbent regeneration devices

- so connected to a steam turbine for using waste heat in the production of pig iron and, if necessary, additionally to a steam turbine of a steam turbine power plant, that low-pressure steam from the steam turbine can be directed at least partially to a part of the absorbent recovery device,

- and / or so connected to a recovery boiler for using waste heat in the production of pig iron and, if necessary, additionally to a recovery boiler of a steam turbine power plant, that low pressure steam can be used at least partially for regeneration of the absorbent,

and wherein at least one pipeline from the group is provided

- a pipeline through which the exhaust gas can be sent from a blast furnace, in particular from an oxygen blast furnace with recirculation of the exhaust gas, to a device for removing CO ₂ by chemical absorption,

- a pipeline through which off-gas can be directed from the reduction device to the CO ₂ removal device by chemical absorption.

By "low pressure steam" is meant water vapor that is saturated and has a pressure of 2-10 bar. The term "steam turbine power plant" means, on the one hand, conventional steam turbine power plants in which thermal energy is produced by burning fuel with which water steam is produced, and it is used in a steam turbine, and ultimately is converted into electrical energy.

On the other hand, a combined power plant comes to mind, more precisely a power plant with combined production of electricity and heat

combined cycle power plant, briefly SSRP), which combines the principles of a gas turbine power plant and a steam turbine power plant. In this case, the gas turbine serves as a heat source for the connected recovery boiler, which, in turn, acts as a steam generator for a steam turbine.

Thanks to the application of the chemical absorption process, the content of the return gases CO, H ₂ , CH ₄ in the production of pig iron increases compared to (V) PSA and the CO ₂ content in the resulting synthesis gas is significantly reduced (up to several volume parts per million).

The use of low-pressure steam from an existing steam process is less costly than producing steam using its own unit for desorption only. In addition, the use of a low-calorie energy carrier, such as steam, should be preferred from an economic and environmental point of view to a high-quality energy carrier, such as electric current. In addition, borrowing steam from an existing steam turbine power plant is possible from a steam generator used as a special generator for CO ₂ removal; fuel for producing steam is better used in a continuous steam process.

The residual gas stream after chemical absorption mainly contains CO ₂ and after removing H ₂ S there are only more traces of H ₂ S and therefore can be released directly into the atmosphere and / or fed to a CO ₂ concentrator followed by storage of CO ₂ (English: Sequestration, for example , EOR - enhanced oil recovery, EGR - enhanced gas recovery) and / or used as a substitute for N ₂ for iron manufacturing: a residual gas stream consists essentially of CO ₂ and can therefore be used for smoothing load isolation seal and purge and cooling gas otrebleniya.

Due to the low content of impurities, the energy consumption for compression of the residual gas stream from chemical absorption to a liquid-solid or supercritical state (> 73.3 bar) is approximately 20-30% lower than for the residual gas from (V) PSA. Therefore, in gas pipelines, the distance between the devices also increases, where the gas must again be compressed. As a result, both capital investment and production costs for storing CO ₂ are reduced.

Compared to adsorption with a differential pressure, chemical adsorption with a slight pressure works with a cleaning gas and a slight pressure drop with the removal of CO ₂ , which also saves energy here. In contrast, the VPSA also does not need any vacuum compressors, which also consume large amounts of energy and cause a high maintenance cost. Low energy consumption is an advantage, first of all, for those countries in which energy is limited and / or expensive.

Now, due to the higher content of combustible materials in the waste gas of pig iron production purified according to this decision, the plant productivity can be increased or their specific consumption can be reduced, or when these gases are burned at a power plant, an increased efficiency of the power plant can be realized.

The investment for a chemical absorption process is comparable to that for a VPSA device. But the absorption process requires large quantities of low pressure steam with a pressure of more than 2 bar or higher, for example, 10 bar. Such steam would be expensive if it had to be produced on purpose and could not be removed from an existing steam source.

There are various chemical absorption methods that are suitable for the present solution:

The first absorption method is characterized by the use of potassium carbonate as an absorbent. Use hot potassium carbonate (English: Hot potassium carbonate (HPC) or "Hot Pot"). Depending on the manufacturer of this method, various materials are added to potassium carbonate: activators, which should increase CO ₂ separation, and inhibitors, which should reduce corrosion. A widespread method of this kind is known as the Benfield method and is proposed by UOP. In the Benfield method, approximately 0.75 kg of steam per normal m ^{3 of} gas to be purified is required.

The second absorption method is known as multistage amine wet scrubbing. In this case, several alkaline aqueous solutions of amines (mainly ethanolamine derivatives), which chemically reversibly absorb acid gases, such as, for example, CO _2, are used in the first stage. In the second step of the method, the acid gas is thermally (heated) separated from the amine and the resulting amine is reused for wet gas treatment.

A known method for this is the Amine Guard FS UOP method, which reduces the CO ₂ content to 50 volume parts per million and the H2S content to 1 volume part per million. This method requires approximately 1.05 kg of steam per normal m ^{3 of} gas to be purified.

Amines, for example diethanolamine (DEA), are also used as activators for the absorption method using potassium carbonate, for example, for the Benfield method.

For amine wet scrubbing, primary amines such as methylamine, monoethanolamine (MEA) and / or diglycolamine (DGA) can be used.

For amine wet scrubbing, secondary amines, for example diethanolamine (DEA) and / or diisopropanolamine (DIPA), can be used in addition to or alternatively to primary amines.

In addition to or alternatively to primary and / or secondary amines, tertiary amines, for example, triethanolamine (TEA) and / or methyldiethanolamine (MDEA), can also be used. In addition, the existing method is an aMDEA method from BASF (proposed by Linde and Lurgi) that uses activated methyldiethanolamine (MDEA). This method requires approximately 0.85 kg of steam per normal m ^{3 of} gas to be purified.

Accordingly, it is possible to advantageously purify CO _{2 from the} top gas from the blast furnace, in particular from the oxygen blast furnace, in which oxygen is mainly used as a hot blast, with the return of the top gas.

The corresponding method is also applicable to exhaust gases from reduction smelting devices, and it is best to combine CO ₂ of at least one of the following exhaust gases:

- exhaust gas (the so-called excess gas) from the melting gasifier (or gas generator),

- exhaust gas from at least one reduction reactor,

- exhaust gas (blast furnace gas, also called top gas) from at least one fixed bed reactor and / or reduction of iron oxides and / or iron briquettes.

In order to better use the reducing components of the gas after the removal of CO ₂ for the production of pig iron, it may be provided that at least part of the cleaned exhaust gas is used again as the reducing gas for the production of pig iron.

To easily obtain low pressure steam, it is best to remove it at the end of the expansion from a steam turbine or a waste heat boiler of a steam turbine.

In particular, for the blast furnace process, a line can be provided along which blast furnace gas can be directed from the blast furnace, in particular from an oxygen blast furnace with the return of blast furnace gas, to a device for removing CO ₂ by chemical absorption.

In addition, in the reduction smelting method, at least a line was suitably provided in which the exhaust gas from the reduction smelting device can be directed to a CO ₂ removal device by chemical absorption.

At least one of these highways can be connected to at least one of the following means:

- with melting gasifier,

- with one or more reduction reactors,

with a fixed bed reactor for heating and / or reduction of iron oxides and / or iron briquettes.

A further embodiment is that a line is provided along which at least a portion of the cleaned exhaust gas can be recycled as reducing gas for the production of pig iron.

For introducing low pressure steam into the CO ₂ removal device, it may be provided that they are connected to the low pressure part of the steam turbine and / or the recovery boiler.

The solution is further explained by way of indicative and schematic figures.

1 shows a phase diagram of CO ₂ .

Figure 2 shows the relationship between the impurities of gases and the necessary compressor stations for transporting liquefied gases.

Figure 3 shows the corresponding relationship between a blast furnace and two power plants.

Figure 4 shows the corresponding relationship between the device for reductive melting and two power plants.

Figure 1 presents the phase diagram of CO ₂ . The temperature in K is plotted on the horizontal axis, and the pressure in bars on the vertical axis (1 bar = 10 ⁵ Pa). Separate aggregate states (solid or solid, liquid substance or liquid and gas or gaseous) are separated from each other by lines.

The triple point is the point where the solid, liquid, and gaseous phases meet.

The supercritical state (supercritical fluid) is the state above the critical point in the phase diagram, which is characterized by the equalization of the densities of the liquid and gas phases. Differences between both aggregative states at this point cease to exist.

Figure 2 presents the relationship between the impurities of gases and the compressor stations necessary for them during transportation of liquefied gases.

Impurities in% of the gas volume are deposited on the horizontal axis, and the distance between the compressor stations in kilometers on the vertical axis.

Each impurity has its own curve.

At 10% impurities (right edge of the image), the smallest effect on the distance between compressor stations at H ₂ S and then SO ₂ , CH ₄ , Ar, O ₂ , N ₂ and CO is equivalent, then NO ₂ , which corresponds to the largest influence H ₂ where the curve goes almost to zero.

Figure 3 presents the oxygen blast furnace 1 with the return of blast furnace gas, which serves iron ore from the sintering device 2, as well as coke (not shown).

Oxygen-containing gas 3 with an oxygen content of more than 80% enters the annular pipe 4, and the heated reducing gas 5, together with cold or heated oxygen O ₂ , enters the blast furnace 1 in the furnace of reducing gases 6. Slag 7 and cast iron 8 are held at the bottom. In the upper part of the blast furnace 1, top gas or blast furnace gas 9 is removed and pre-cleaned in a dust separator or cyclone 10 and again cleaned in a wet scrubber 11 (or in a bag filter or hot gas filtration system). On the one hand, such purified top gas or blast furnace gas can be directly removed as export gas 12 from the blast furnace system and fed to the gas export tank 13, and on the other hand, it can be supplied to the CO ₂ chemical absorption device 14, the top gas or blast furnace gas was previously compressed in the compressor 15 at about 2-6 bar and cooled in an additional refrigerator 16 to about 30-60 ° C.

The CO ₂ chemical absorption device 14 consists essentially of an absorber 17 and a stripper 18. Such devices are known in the art and therefore should be described here only in general terms. In the absorber 17, the purified top gas or blast furnace gas 9 is supplied from below, while the acidic components of the gases of the absorbing solution — the amine solution — are directed downward from above. Here, CO ₂ is removed from the top gas or top gas and the purified gas is again fed to the blast furnace 1.

The filled absorbent (absorbent liquid) is sent from above to the stripper 18, where it is heated with warm low-pressure steam 19, which has a temperature of about 120-260 ° C, in particular 150 ° C, to> 100 ° C, in particular 110-120 ° C, whereby acidic gases, in particular CO ₂ , are again released as residual gas 20. Residual gas 20 can either be discharged to the atmosphere again and / or purged from H ₂ S 21 and / or fed to the next compressor 22 to liquefy CO ₂ so that it can then be transferred and stored, for example, underground, or to use it o as a replacement for nitrogen in iron production.

The condensate 23 entering the stripper is discharged and can be supplied to the steam circulation of the steam turbine power station 32.

Export gas from the additional tank for export gas 13 can be supplied to the combined power plant 24 as fuel, if necessary, through the buffer tank 25 and filter 26. Export gas is supplied to the gas compressor 27 and the gas turbine 28. The waste heat from the gas turbine is used in the boiler a waste heat exchanger 29 for circulating steam with a steam turbine 30. Also from this steam turbine 30, low pressure steam could be withdrawn for stripper 18 (not shown).

Alternatively or in addition to the combined power plant 24, the export gas 12 may, if necessary, also be supplied through another export gas tank 31 to the steam boiler 33 of the steam turbine power station 32 as fuel. From it or the last stages of the steam turbine 34 of the steam turbine power plant 32, low pressure steam 19 is withdrawn and fed to the stripper 18.

The energy intensity of the pressure of the export gas 12 can also be used in the expansion turbine 35 (eng: Top gas pressure recovery turbine), which is located in this example between the tank for export gas 13 and the additional tank for export gas 31.

Neither in the combined power plant 24, nor in the steam turbine power plant 32, the necessary export gas 12 can be used for other purposes, for example, for drying raw materials (coal, coal fines or ore) 36.

FIG. 4 shows a corresponding connection between a remelting melting apparatus and two power plants, namely a combined power plant 24, shown in detail in FIG. 3, and a steam turbine power plant 32, also with a similar construction as in FIG. 3. Also, in FIG. 4, only a combined power station 24, or only a steam turbine power station 32, or both a combined power station 24 and a steam turbine power station 32 can be provided.

Both power plants 24, 32 are equipped with a Finex export gas device 12, which can be stored in an intermediate accumulated export gas tank 13 or 31. Additionally, an expansion turbine 35 is used to reuse the energy stored in the export gas 12. The export gas 12 required for the power plants 24, 32 cannot be supplied again for drying the raw materials 36.

The Finex device in this example has four 37-40 reduction reactors, which are designed as a fluidized bed reactor and are loaded with ore fines. Ore fines and additives 41 are dried 42 and from there they go first to the fourth reactor 37, then to the third 38, second 39 and finally to the first reduction reactor 40. However, instead of four fluidized bed reactors 37-40, only three can be available .

Reduction gas 43 is supplied to the ore fines in countercurrent flow. It is introduced at the bottom of the first reduction reactor 40 and exits at the top. Before it enters the bottom of the second reduction reactor 39, it can be heated with oxygen O ₂ , also between the second 39 and third 38 reduction reactors. The heat of the exhaust gas 44 from the reduction reactors 37-40 is used in a waste heat boiler 45 for energy production, while the resulting low pressure steam 46 is supplied to the stripper 18 of the chemical absorption device CO ₂ .

The exhaust gas 44 leaving the waste heat recovery boiler 45 is cleaned in a wet scrubber 47 and then used as export gas 12, as described above in series-connected power plants. A partial stream of exhaust gases 44 is fed to the adsorber 17 for purification from CO ₂ .

The reducing gas 43 is produced in a melting gasifier 48, into which coal in the form of lump coal 49 and coal in the form of powder 50 together with oxygen O ₂ are supplied on one side, and on the other hand, a molded iron ore partially restored in reduction reactors 37-40 is added and in the form of briquettes when briquetting iron 51 in a hot state (English: HCl Hot Compacted Iron). In this case, iron briquettes fall through conveyor 52 into storage tank 53, which is made in the form of a fixed-bed reactor, where iron briquettes, if necessary, are preheated with crudely purified generator gas 54 from the melting gasifier 48 and restored. Cold iron briquettes 63 can also be added here. Then, iron briquettes or iron oxides are charged from above into the melter gasifier 48. Low-reduced iron (engl. LRI = low reduced iron) can also be removed from iron briquetting 51.

Coal is gasified in the melting gasifier 48 and a gas mixture is formed, which consists mainly of CO and H ₂ , and is withdrawn as a reducing gas (generator gas) 54 and a partial stream is supplied as reducing gas 43 to the reduction reactors 37-40.

Hot metal and slag melted in the melting gasifier 48 are discharged, see arrow 56.

The exhaust gas 54 removed from the melter gasifier 48 is first supplied to a separator 57 in order to separate it from the outgoing dust and return the dust to the pulverized coal burner of the melter gasifier 48.

A portion of the top-gas purified from coarse dust is then cleaned by means of a wet scrubber 58 and taken as excess gas 59 from the Finex device and fed to the absorber 17 of the device 14 for chemical absorption of CO ₂ .

Another portion of the cleaned generator gas 54 is also further cleaned in a wet scrubber 60, fed to the cooler of the gas compressor 61, and then, after mixing with the CO ₂ -based generator gas 62, is again fed to the generator gas 54 after the melting gasifier 48 for cooling. Due to this recirculation, the CO ₂ -based gases 62 containing reducing components can still be used for the Finex method and, on the other hand, provide the necessary cooling of the hot generator gas 54 from about 1050 ° C to 700-870 ° C.

The flue gas 55 leaving the storage 53, where iron briquettes or iron oxides with dust-free and cooled generator gas 54 from the melting gasifier 48 is heated and reduced, is cleaned in a wet scrubber 64 and then fed to an absorber 17 to remove CO ₂ .

Low pressure steam 46 from the recovery boiler 45 and / or low pressure steam 19 from the steam turbine 30 of the combined power plant 24 and / or low pressure steam from the steam turbine 34 of the steam turbine power station 32 can also be supplied to the stripper 18. Preferably, the waste heat from the iron production process should be used due to short sections of the path between the waste heat boiler and the device for chemical absorption of CO ₂ .

In this example, the condensate 23 of the stripper 18 is fed to the steam circulation of the steam turbine power station 32. However, it can be supplied to a recovery boiler or a combined power station.

The residual gas 20 after the stripper 18 can again be released into the atmosphere, in whole or in part after purification from H ₂ S 21, or in whole or in part after liquefaction by means of the compressor 22, to be stored in CO ₂ .

Designation List

1 blast furnace

2 sintering device

3 oxygen-containing gas

4 ring pipeline

5 hot blast

6 gas recovery furnace

7 slag

8 cast iron

9 top gas or top gas

10 dust separator or cyclone

11 wet scrubber

12 export gas

13 tank for export gas

14 chemical absorption device CO ₂

15 compressor

16 additional refrigerator

17 absorber

18 stripper

19 pairs of low pressure

20 residual gas after stripper 18

21 cleaning H ₂ S

22 CO ₂ liquefaction compressor

23 condensate

24 combined power plant

25 buffer capacity

26 filter

27 gas compressor

28 gas turbine

29 waste heat boiler

30 steam turbine

31 additional tank for export gas

32 steam turbine power station

33 steam boiler

34 steam turbine steam turbine power station 32

35 expansion turbine

36 drying of raw materials (coal, coal fines or ore)

37 fourth recovery reactor

38 third recovery reactor

39 second recovery reactor

44 exhaust gases from reduction reactors 37-40

40 first recovery reactor

41 ore fines and additives

42 ore drying

43 reducing gas

45 waste heat boiler

46 low-pressure steam from the recovery boiler 45

47 wet scrubber for exhaust gas 44

48 melter gasifier

49 lump coal

50 powder coal

51 iron briquetting

52 lifting device

53 made in the form of a fixed-bed reactor storage tank for heating and reducing iron oxides and / or iron briquettes

54 waste gas or generator gas from the melter gasifier 48

55 wet scrubber top gas 64

56 hot metal and slag

57 ore separator

58 wet scrubber

59 excess gas

60 wet scrubber

61 gas compressor

62 freed from the CO ₂ gas (syngas) from the absorber 17

63 cold iron briquettes

64 wet scrubber

Claims (10)

1. A device for removing CO ₂ from the exhaust gases (12, 44, 55, 59) of devices for the production of cast iron, in which a device (14) for removing CO ₂ by chemical absorption is provided, wherein steam is used to regenerate the absorbent, characterized in that part of the device (17) for the regeneration of absorbent - is so connected to a steam turbine (30) for using waste heat in the production of pig iron and, if necessary, additionally to a steam turbine (34) of a steam turbine power plant (32), so that low-pressure steam from the steam turbine (30, 34) can be sent, at least , partially to a part of the absorbent regeneration device (17), - and / or so connected to a recovery boiler (29) for using waste heat in the production of pig iron and, if necessary, additionally to a recovery boiler (33) of a steam turbine power plant, so that low pressure steam can be used at least partially for regeneration of the absorbent, and wherein at least one pipeline from the group is provided: - a pipeline through which the exhaust gas (12) can be sent from a blast furnace, in particular from an oxygen blast furnace (1) with recirculation of the exhaust gas, to a device (14) for removing CO ₂ by chemical absorption, - a pipeline through which off-gas (44, 55, 59) can be directed from the reduction device to the device (14) for CO ₂ removal by chemical absorption. 2. The device according to claim 1, characterized in that at least one of said pipelines is connected to at least one of the following devices: - with a melting gasifier (48), - with one or more reduction reactors (37-40), - with a fixed bed reactor (53) for heating and / or reduction of iron oxides and / or iron briquettes. 3. The device according to any one of claims 1, 2, characterized in that a pipeline is provided through which at least a portion (62) of the cleaned exhaust gas can again be discharged as reducing gas for the production of pig iron. 4. The device according to any one of claims 1, 2, characterized in that for introducing low pressure steam into the device for CO ₂ removal it is connected to the low pressure stage of the steam turbine (30, 34) and / or to the recovery boiler. 5. A device according to any one of claims 1, 2, characterized in that the device (14) for removing CO ₂ by chemical absorption is so connected to a device for producing cast iron and / or a device for preparing and storing CO ₂ such that the resulting CO ₂ -gas gas can be used as a substitute for gas in the process of iron production and / or for the preparation and storage of CO ₂ . 6. The device according to any one of claims 1, 2, characterized in that the absorbent is potassium carbonate. 7. The device according to any one of claims 1, 2, characterized in that it includes an amine unit for wet gas purification. 8. The device according to claim 7, characterized in that the amine wet scrubber is designed to use primary amines, such as methylamine, monoethanolamine (MEA) and / or diglycolamine (DGA). 9. The device according to claim 7, characterized in that the amine wet scrubber is designed to use secondary amines such as diethanolamine (DEA) and / or diisopropanolamine (DIPA). 10. The device according to claim 7, characterized in that the amine wet scrubber is designed to use tertiary amines such as triethanolamine (TEA) and / or methyldiethanolamine (MDEA).

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