DE1914400B2 - Method and device for the direct reduction of iron ores - Google Patents

Description

3 4

to create that with proper avoidance of a water vapor used in the reaction of the CC

Catalytic poisoning a very economical operation and H ₂ ent with the iron oxide in the reduction process

of a large-scale system. stand. For the continuous catalytic conversion uni

The solution according to the invention consists in an indirectly heated gas converter Method of the generic type in that the 5 As shown in FIG. 1 can be seen, is a vertical, somewhat

A cylindrical reduction shaft furnace 10 made exclusively from gaseous hydrocarbons is present

and exhaust gas existing mixture before entry into the at its upper end a funnel Ii

Catalj tbett of the gas converter in non-catalytic has and in the iron oxide pieces 14 or other:

The environment is preheated to the reaction temperature and material containing iron oxide is entered. Tue (

is and that the reducing gas generated get to io iron oxide pieces 14 by means of gravity

Admixture of further exhaust gas to adjust the flow through an inlet pipe 16 into the reduction shaft

Desired reduction temperature directly in oven 10. At the bottom of the reduction shaft oven K

the reduction shaft furnace is initiated. is an outlet pipe 18 for the metallized irons

This ensures that even without bits. A discharge conveyor 20, for example excessive water vapor supply to convert 15 an electrically driven vibration conveyor, the exhaust gas no catalytic poisoning occurs, whereby one is provided under the outlet pipe 18,
Overall, very high reaction temperatures in the upper area of the reduction shaft furnace K is obtained. Since, on the one hand, the converted gas is already provided, a ring line Bla.swerk 22 is provided with which has a desired high temperature and, on the other hand, hot reducing gas d '.... irt any admixtures that are withdrawn from it again so that it is introduced into the furnace upward in the flow to the material values are not contained in it, the piece 14 can flow and exit the furnace by a converted gas in a simple and very economical way shown to the desired reduction temperature. The inlet pipe 16 extends adjusted into the reduction shaft furnace until the outlet 24 is below the mouth opening. Since the for the catalytic conversion 25 This creates a collecting space 26 for the exhaust gas, required oxygen exclusively from the exhaust gas so that this stems evenly from the mass of iron, no additional oxygen sources required pieces escape and are freely borrowed to the outlet 24 and after Implementation nothing can flow excreted.

In the lower area of the reduction shaft furnace IC

thermal efficiency achieved. 30 there is a closed circulation system 27,

The invention also relates to a device to the pieces of material before they exit from the

Implementation of the procedure. Starting from an oven to cool. The circulation system 27 includes!

Device with a single closed rear an indirect cooler 28, a gas blower 30, a

lead away from the outlet of the exhaust gas from the reducing gas inlet 32 and a gas outlet 34. The fan 3Ü

A shaft furnace for introducing the reducing gas in 35 is in the inlet pipe 31 which is connected to the cooler 28

the reduction shaft furnace and one in the back to the gas inlet 32 is switched on. Dei

Lead-mg arranged mixing device for the umzu- gas inlet 32 is a in the reduction shaft furnace IC

changing gases and a continuously working gas distributor. The gas outlet 34 is above

the, indirectly heated catalytic gas converter, the gas inlet 32 and is with the cooler 28 through

the device according to the invention consists in that a pipe 33 is connected at 4 °.

between the mixing device and the catalytic converter to obtain a hot reducing gas of the gas converter, a device is provided to advance a gas converter 38 which heats the fuel of the gas mixture is arranged, which has non-operated burner 40, has an exhaust pipe 42 contains catalytic material, and that further comprises and with a plurality of indirect heat-out return conduits is provided for the exhaust gas with the reduction 45 exchanging catalytic tubes 44, which by gas pipe can be heated outside for the purpose of setting the temperature. In the F i g. 1 and 2 is respectively is connectable. only one of these catalytic tubes 44 is shown. That

One embodiment of the subject matter of the invention, reducing gas flows from the catalyst tubes 44 is described below with reference to the drawing the ring line blower unit 22 by a reduction described in more detail. It shows 50 gas line 46 into which a gas analyzer 47 is inserted.

F i g. 1 is a schematic representation of an upstream circuit.

direction according to the invention, at the same time in the form of a Das from the reduction shaft furnace 10 through the

Diagram of the process steps, exhaust gas flowing out of outlet 24 initially arrives at

F i g. 2 shows a sectional view of the gas converter of a cooling cleaning device 60 in which it is cooled and

as part of the device according to FIG. 1, 55 is freed from scrub. A device becomes useful

F i g. 3 a diagram of the heat demand of the one used with direct water contact, for example

Procedure with varying working conditions, a device with a tightly packed countercurrent tower,

F i g. 4 shows a diagram of the reducing gas in which the gas flows upwards and the cooling water

Quantity requirement of the process with varying work due to gravity down through the packing material

conditions. 60 flows. The condensation point temperature of the off

In the method for the direct reduction of iron earth exhaust gas coming from the outlet 24, zen in a shaft furnace by means of a reducing gas is considerably higher than that which is usually prevailing, to cool _{water temperature for CO and H 2} for the reduction process, and it is in terms of gain, a continuous catalytic conversion thermal utilization is advantageous, as much water of a gaseous hydrocarbon, such as steam, as possible and, depending on the respective operating mode, natural gas or another hydrocarbon that is easy to condense from the exhaust gas, is carried out. For the sier.
Implementation are used as oxidants CO ₂ and a large part of the cooled exhaust gas from the

Cooling cleaning device 60 is conducted to a compressor 62 by means of a return line 64. Natural gas or other hydrocarbon-containing fuels in gaseous form, each originating from a storage device 66, are mixed in a mixing device 68 with the cooled exhaust gas from the compressor 62. The amount of admixed hydrocarbon is controlled by a valve 65 which responds to the gas analyzer 47, which in turn _{controls the CO 2} content (or some other specific component) in the converted reducing gas after the gas converter 38. An inert cleaning gas is used at the beginning and at the end of the process sequence. This can be obtained in the relatively small amount that is only required in the meantime, in that some of the combustion gases created by the burners 40 in the gas converter 38 are drawn off and cooled. For this purpose, a line 69 is provided which leads from the gas converter 38 to the mixing device 68 and into which a valve 70 and a cooler 71 are connected. The return ^f ührleitung 64 and the burner 40 are connected by a further line 72 through which flows the remaining portion of cooled and purified flue gas to the burners to the labels in this excess fuel exhaust exploit. A fan 73, a valve 74 and a pressure-sensitive control element 76 are connected to the line 72. However, the calorific value of the excess cooled exhaust gas is not sufficient to cover the heat demand of the gas converter 38. Therefore, additional fuel, such as heating oil or natural gas, is supplied from an additional fuel reservoir 78, which is connected to the line 72 by a line 79 having a control valve 81.

The combustion air for the burners 40 is supplied by a fan 80. The gas converter 38 normally operates at temperatures of 982 to 1037 ⁵ C. At this operating temperature, it makes economic sense to provide a preheater 82 in order to preheat the combustion air for the burners 40 to temperatures of 426 to 760 ° C. This is done by exchanging heat with the hot exhaust gas that enters the gas converter 38 via a vent 42 . The preheated air passes from the preheater 82 through a line 84 to the burners 40 and reduces the additional amount of fuel required for the process sequence from the fuel reservoir 78 to a minimum. The preheater 82 is provided with a ventilation pipe 86 through which the exhaust gases can escape.

The flow of additional fuel from the fuel reservoir 78 is controlled by the control valve 81 in the line 79, which operates as a function of a temperature element 90 which is arranged in the gas converter 38. The usual control devices for the ratio of air to fuel are also provided in order to meter the inflow of combustion air to the burners 40 as a function of the inflow and the calorific values of the gases to be converted and the additional fuel.

If the exhaust gas coming from the reduction shaft furnace 10 is not excessively laden with dust , the portion of this exhaust gas routed to the burners 40 of the conversion furnace can bypass the cooling cleaning device 60, as indicated by dashed lines for a line 72 '. The burners 40 can withstand a certain proportion of dust, while the exhaust gas to be fed to the gas converter 38 should be as dust-free as possible in order to prevent the catalytic bed from clogging.

As shown in FIG. 2, an inlet 92 for the supplied mixture is attached to the lower end of the catalytic tube 44. The catalytic tube 44 is made of a heat-resistant alloy, preferably the heat resistance to temperatures of

ίο is designed around 926 to 1093 ⁰ C. In order to preheat the incoming mixture to the transition temperature, the gas inlet end of the catalytic tube 44 is packed with a non-catalytic, refractory piece of material 94 which rests on a correspondingly shaped grid 96. In the direction of flow behind this fire-resistant piece of material 94 is the catalytic bed with the catalyst 98, a catalyst based on nickel being expediently used. At the exit of the catalytic tube

44 an insert 100 made of heat-resistant material is provided, which is surrounded by insulation 102 , with which heat radiation losses at the tube outlet are prevented. The reducing gas line 46 is attached to the insert 100 and leads the hot reducing gas directly to the reduction shaft furnace 10. The reducing gas line 46 is preferably lined with an insulating insert 104 in order to keep heat losses as low as possible.

The temperature of the Katalytröhren 44 leaving the hot reducing gas is in normal operation to 93-149 ⁰ C higher than the temperature which is preferred for the operation of the reduction shaft furnace 10th In order to cool the reducing gas to the desired temperature, a portion of the cooled exhaust gas from the recirculation inlet line 64 can be mixed with the hot reducing gas in the reducing gas line 46. A control system 48, which consists of a line 50, a blower 52 and a gas flow control valve 54 which responds to a thermoresponsive element 56, is used for this purpose. The cooled exhaust gas has useful reducing properties thanks to its high CO and H ₂ content as a result of the condensation of water vapor in the cooling cleaning device 60, so that the degree of heat utilization can be improved by its supply.

During start-up operation, the gas converter 38 is brought to operating temperature by air from the fan 80 and fuel from the fuel store 78, and the reduction shaft furnace 10 is filled with cold iron oxide pieces. Combustion products of the gas converter 38 are sucked off through the line 69, cooled in the heat exchanger 71 and introduced into the mixing device 68.

The compressor 62 is then started and the entire system is vented by opening the fan 73 in the line 72. After this purification, gaseous carbon is gradually fed to the mixer 68 and the reaction begins, the CO ₂ and the remaining water vapor from the combustion products being used as oxidizing agents for the reaction. After the piece goods are heated in the reduction furnace and begin to reduce and thus CO ₂ and water vapor

are formed in the reduction shaft furnace the flow of combustion products to the mixing device 68 through the line 69 is switched off. When the exhaust gas from the reduction shaft furnace

has reached a corresponding calorific value that causes its condensation of water vapor to occur Allowing combustion in the gas converter, volume reduction .st is considerably less than that the vent 73Tn of the line 72 closed and the volume increase during the implementation in the V 11 74 eeoffiet catalytic tubes 44. There is thus an excess

Pe the mixing device 68 from the storage 66 5 of cooled exhaust gas in the recirculation line 64 is converted into the catalytic via the amount of gas that pipes 44 from the compressor 62 in order to win _{CO and H 2.} is processed. This excess exhaust gas is available for this purpose with the CO ₂ and the remaining gas as fuel for the burner 40, and water vapor reacts in the cooled exhaust gas, which is used to generate heat for the gas conversion 38, the? Mixing device 68 from the compressor 62 »o Em very significant proportion of the; required heat is supplied. This already covers the amount of carbon added for the catalyzer tubes, hydrogen is preferably close to - but not all excess gas - is expediently set above that for the stoichiometric reaction. The pressure-sensitive element 76 is used for this purpose, with CO ₂ and water vapor in the cooled exhaust gas the gas flow valve 74 in which the excess is required. The amount of cooled exhaust gas, which is operated by line 72 that controls the exhaust gas, is such that it feeds the compressor 62, a return pressure is automatically set to the required return pressure to maintain the created at least three working conditions: First of all, the desired ratio, depending on the, the compressor 72 works with a positive gas pressure inflow of cooled exhaust gas controlled. ao on its inlet side, whereby its pump effect

Thus, the mixture to be converted consists of being improved; second, the reduction works after all from gaseous hydrocarbon and shaft furnace 10 with a positive pressure in semem Exhaust gas In start-up operation, the fan 80 acts as a collecting space 26, which prevents air from being released Source of oxidizing agent, but after the reduction of the in this system through the inlet pipe 16 for the Piece goods and after closing the valve 70 comes = 5 iron oxides seep in; third, thanks to the the required oxidizing agent exclusively from the controlled positive gas pressure in the line 72 ? ückRut and an additional oxidant supply all excess, cooled exhaust gas through this from the outside is not required. Line 72 to the burners 40.

The temperature of the reducing gas is preferred in the diagram as F 1 g. 3 is the entire

wisely kept between about 704 and 788 ° C in order to prevent a fuel requirement of the process depending on the sticking together of the metallized iron pieces and the ratio of reducing agents (CO and H ₂ ) Vu ". The control system 48 serves for this purpose to oxidizing agents (CO, and H ₁ O), η the reducing agent ratio of reducing agents (CO and H ₂ ) toon gas. The total fuel _{requirement 7U} oxidizing agents (CO, and H ₂ O) is preferably m kcal / kg produced in the reduction shaft furnace in one Value of "9: 1, possibly 35 metallic E.sens shown, based on the higher held. This happens through the gas conversion of high quality hematite iron oxide device47, which controls the influx of coal pieces into highly metalized pieces of iron Das DiawasseS to the mixing device 68. The diagram clearly shows the technical advantage due to the fact that there is a very good overall heat utilization of the production of a reducing gas with one tad, and there is also a high ratio of reducing agent to oxide metallization with economically pleasing shortness of the reducing agent. It should be emphasized that in the case of a duration of the proceedings. In addition, the resulting ratio of reducing agent to oxidizing agent reduced iron pieces have a controlled carbon content of the order of 9: 1, the curve sharp, so that it increases as molten material with the further upward. _λ ■. _A - "

processing are particularly valuable. 45 In the diagram according to F 1 g. 4 is the amount of

In the conversion of hydrocarbon to the process results zuzutiinrenden reducing gas per each unit volume of CO _2, which reacts produced by the CARBON kilograms of metallic iron also in the hydrocarbon, two volume m depending on the ratio voaReduküonstinh _e itenCO, undjedeVolumeinheitWasserdampf, the medium to Oxydaüonsmittel in Reducing gas reacts with the carbon in the hydrocarbon, 50 provided. The amount of the necessary reducing gas St a unit volume CO and a unit volume has a significant influence on the size of the H In addition to this increase in volume is Gasumwandlers 38 of Reduktionsoer hydrogen radical from the hydrocarbon in the H ₂ shaft furnace 10 and the height of the power fm converted Large what a further increase in volume the compressor 62 is required, which is ultimately the. SedluTet thus leaves a considerably larger 55 process sequence with regard to the gas volume than the volume, the basic method of direct reduction finds the conversion of hematite (Fe ₂ O ₃ ) into metallic «" h 44 t tt ^iron ( ^Fe ) " ¹ ^ ^komeninonox y ^{d or} hydrogen ir

WährTnd ^ derVeduktionsreaktionen in the reductive stages corresponding to the specified below tion shaft furnace 10 is subject to the supplied reductive instead of 60 reactions, each on a mole of iron tion gas based no change in volume before it from the _F ,, _o

Outlet 24 exits. Thus, each volume unit gives 1. V ₂ Fe ₂ O ₃ -T / β ^ Ο- / ^ e ₃ O ₄ + Z ₆ CO ₂ , CO, which reacts with the iron oxides, a volume of 2. ¹ I ₃ Fe ₃ O ₄ + Vs CO = FeO + V ₃ CO ₂ , unit of water vapor. _{Therefore, the 65 4} ^ ^^ _{+ 1 / A =} ^ j ^ ₊ ^ _R ^ gas volume exiting through the outlet 24 into the reduction 3 _Fe0 + CO = Ft _r CO ₂ and tion shaft furnace 10 is essentially equal to that of the gas volume in the

Reduction shaft furnace 10 entering gas volume. > · I ****> * + /. «. reu -r /, « ₂ u, The in the cooling cleaning device 60 due to the 6th FeO -j- H ₂ - te + H ₂ U.

In every direct reduction process, the reducing agents CO and / or H ₂ in the reducing gas cannot react until they are completely consumed because the oxidizing agents CO ₂ and H ₂ O are formed as the reduction progresses. The end limit for the use of CO and / or H ₂ in the reduction is defined by an equilibrium _{ratio between CO and CO 2} and H ₂ and H ₂ O. This ratio can be determined experimentally or calculated from thermodynamic tables. For example, these ratios for the above equations 1 to 6 at 76O ⁰ C are as follows:

1. C0 / C0 ₂ = 1 x 10 ^5,

2. CO / CO ₂ = 62,

3. C0 / C0 ₂ = 1.65 and

4. H ₂ / H ₂ O = 1.4 x 10- ^6,

5. H ₂ / H ₂ O = 0.70,

6. H ₂ / H ₂ O = 2.0.

In a cylindrical reduction shaft furnace which works in countercurrent, the abovementioned reactions can essentially be carried out up to the stated> 5 equilibria. This type of furnace is particularly suitable for a treatment time of 3 to 4 hours for the solids in the reduction zone and it also gives excellent contact between the gas and the solids. The diagrams of FIG. 3 and 4 are based on the reactions proceeding to equilibrium in the reduction shaft furnace using natural gas with a high CH ₄ content as a gaseous hydrocarbon for the conversion.

Up to now, steam has been used on a large scale as a converting oxidizing agent in the conversion of gaseous hydrocarbons. In the process according to the present invention, CO _{2 is} used as the oxidizing agent for the conversion. The reaction with steam (H ₂ O) is a strongly endothermic process. The implementation with CO ₂ is this to an even greater extent. The conversion with the help of air, on the other hand, is to a much lesser extent an endothermic process. The following are the known conversion reactions based on a gaseous hydrocarbon (CH ₄ ), which is the main hydrocarbon in natural gas:

1. CH ₄ -1- H ₂ O = CO + 3 H ₂ .

The endothermic calorific value is 3 106 kcal / m ³ of converted CH ₄ .

2. CH ₄ -f CO ₂ = 2 CO + 2 H ₂ .

The endothermic calorific value is 3533 kcal / m ³ of converted CH ₄ .

3. CH ₄ + V ₂ O ₂ + 2 N ₂ = CO + 2 H ₂ 4- 2 N ₂ .
The endothermic calorific value is 917 kcal / m ⁵ of converted CH ₄ .

5 °

55 The specified endothermic heat demand is based on a mixture temperature of 25 ° C and a Temperature of 871 ° C for the converted gas.

The comparison shows the superiority of the reaction with CO ₂ , especially since the completely excessive ratio of steam to hydrocarbon to avoid catalyst poisoning with all its disadvantages in the reaction with H ₂ O must also be taken into account.

During the reaction it has been found to be important to preheat the mixture to be reacted to a temperature of at least 816 ° C. before it comes into contact with the catalyst, since this protects the catalyst from carbon poisoning. The mixture to be preheated and subsequently reacted contains larger amounts of CO, CO ₂ and H ₂ , a small amount of H ₂ O and the gaseous hydrocarbon. When preheating of such a mixture, the CO disintegration and the discharge is subject of carbon in the temperature range 316-649 ⁰ C by the known reaction formula 2 CO = CO ₂ + C. In addition, the hydrocarbon undergoes thermal cracking with delivery carbon and release of H ₂ at temperatures above about 649 ° C. In order to achieve the preheating of the mixture without the carbon deposition being disruptive, it has been found that the heat exchanger used for the preheating should be made of a refractory material that is non-catalytic for both CO decomposition and is also for the thermal cracking of the hydrocarbon. Molten alumina chunks have been found to be very useful as a refractory material in this regard. It is believed that most of the metal oxides, which cannot be _{reduced to the metal form by CO or H 2} , under the operating conditions prevailing in the preheater, as. non-catalytic material are suitable. For example, magnesium oxide, silicon oxide, and chromium oxide are thought of.

It has also been found to be important to keep the catalyst at a temperature of at least around 816 ° C to avoid physical damage caused by carbon deposits in the catalytic pores to avoid.

A preferred lump of catalyst is in the present case with regard to a high temperature in the core of the catalytic bed one with good thermal conductivity and good porosity. A catalyst made of tabular aluminum oxide of high purity, impregnated with about 5 to 10% nickel proved to be particularly suitable.

The following table shows representative gas analyzes. The analyzes are based on the use of a natural gas with a high CH _r content as a gaseous hydrocarbon. In this table, the hydrocarbon is referred to as CH, before the reaction.

CO 36.6
48.8
37.4
43.1 CH ₄ CO ₂ H ₂ O O, N ₂ *) Mixture in the mixing device 68
Reducing gas in line 46
Abeas in outlet 24 26.6
46.2
27.1
31.2 15.3
0.2
0.4
0.5 19.0
1.8
19.4
22.3 0.8
1.2
14.0
C, 9 0.0
0.0
0.0
0.0 1.7
1.8
1.7
2.0 Cooled exhaust gas in line 64

*) Not measured, but calculated.

H 18 ° -'CO, and 1.2% H ₂ O reduction shaft furnace turned a stay

^at

^{in the 10th}

It Γ as well from the standpoint of the thermal It is as well fromι ai ζ _{χ h} ,

ÄSfdS ¹ UmSe "ngerdesired, a noticeable point of view of the implementation e ^ _e m exhaust gas

Reduction of CO ₂ ^ and H, GehaUes.η de g

r ^ Sr i Udl for example

ί Hpr percentage aTz
great the I rozentsaiz

ΑΑ

from an outside lunque B j

_{The lower the} amount applies for each ΐ- CO and ffin dL

Α — Απ <ann! dS mixture of trains and hydrocarbons. <ann, _{M an}

ijffleJTSSeÄ. ReduküomS with a predetermined ^u ^ ^eset ^ ^e ^ ^, t to win. In Hindie "conversion ² ng itself, the greater the ratio of H to hydrocarbon in the mixture to be converted, the lower the tendency for carbon to be deposited on the catalyst. The presence of hydrogen in the mixture to be converted has the effect of reducing the to suppress the decomposition of hydrocarbons to carbon and hydrogen when the mixture is heated

high-quality iron ore concentrates made with fisenox pieces with an average size from 9 5 to 15.8 mm in diameter S series of experiments on the direct round. A reduction temperature of 788 ° C was found proved to be advantageous, with ReduSnstem «raSir of 816 ° C already one The tendency to pack up and clump together General cargo was present, which refers to the free S downward passage of the Γη disturbing the reduction shaft furnace aiSkte At a reduction temperature of 788 ° C and with the introduction of cold pieces of iron oxide into the can by controlling the ratio of hydrocarbon to oxidizing agents in the mixture to be reacted can be controlled. With a ratio of Reducing agents to oxidizing agents of about 50: 1, the iron pieces contained about 2.0% carbon. At a ratio of about 20: 1, the pieces of iron contained about 0.5% Kolenstoff. At a Ratio of 9: 1, the Kolenstoff content is about 0. In addition to controlling the ratio from reducing agents to oxidizing agents in the hot reducing gas can also be controlled Amount of gaseous hydrocarbon in the hot reducing gas before it enters the Reduction furnace can be added to achieve the desired carbon content in the metallized pieces reach.

The method thus makes it possible in a simple manner to determine the amount of carbon in the metallized pieces provide at least sufficient to convert the remaining iron oxide in these pieces to metallic iron to reduce if this piece goods is later melted. The carbon is inside these pieces extremely effective for reducing the residual iron oxide during melting. It has been found, for example, that when melting in an electric arc furnace of about 201 96% metallized piece goods with an average carbon content of around 1.5% 99% of the total iron present in the piece goods was present in the steel produced. Of the Carbon in this piece goods was partly as free carbon in the pores of the piece goods, partly as Iron carbide present.

It goes without saying that larger EisenoxydbrocK 1 and Reduce iron oxide in the form of fine material with the same advantages.

1 sheet of drawings

Claims (9)

1 2 characterized in that in the reducing gas line claims: (46) a gas analyzer (47) is arranged with which the hydrocarbon feed to the mixing 1. Method for the direct reduction of iron ore device (68) is controllable.
in a shaft furnace by means of a reducing gas, 5 continuously in an indirectly heated gas converter by converting gaseous Hydrocarbons with some of the exhaust gases
of the reduction process is generated thereby marked that the exclusively io from gaseous hydrocarbons and exhaust gas The invention relates to a method for direct existing Mixture before entering the catalytic bed reduction of iron ores in a shaft furnace by means of of the gas converter in a non-catalytically acting reducing gas, which is continuously in a Environment preheated to reaction temperature indirectly heated gas converter by reaction is and that the reducing gas generated after 15 of gaseous hydrocarbons with a part Admixture of further exhaust gas to adjust the exhaust gases of the reduction process is generated. the The invention also relates to a device for through-ware is introduced into the reduction shaft furnace, this process is carried out. 2. The method according to claim 1, characterized in that the US Pat. No. 3,375,098 is characterized in that the catalytic bed is kept at a temperature of at least 816 ^C C for the extraction of iron from a reduction process. Iron oxides known, in which the iron oxide contributes 3. The method according to claim 1, characterized in increased temperature with a reducing gas draws that the relationship is brought about by reducing touch. Through the reduction to oxidizing components in the reducing gas reaction, an exhaust gas is produced, and the reducing and thus the carbon content of the contained gas requirement is partially or completely thereby metallic iron is controlled. covered that at least part of the exhaust gas with 4. The method according to claim 3, characterized thereby mixed gaseous hydrocarbon and that shows that the ratio of reducing to mixture by an oxidizing one at a high temperature Constituents in the reducing gas is directed to borrowed regenerative cracking furnace, at least 9: 1 is maintained. 30 In order to have at least one more or less continuous 5. The method as claimed in claim 1, thereby achieving the characteristic borrowed operation, two regeneratively working draws that the exhaust gas is necessary in known cracking furnaces, which in the cracking furnaces during Way before mixing with the carbon - the conversion period occurring soot deposit hydrogen to a temperature below the condensation point during the following heating period is cooled. 35 need to be burned. This way of working is inhospitable 6. A device for carrying out the process economically and also performs zn a- high load according to any of claims 1 to 5, wherein a and rapid wear of the cracking furnaces by the single closed return path from the outlet of soot combustion. of the exhaust gas from the reduction shaft furnace It is also known that implementations of the in to the inlet of the reducing gas in the reducing 40 question type of hydrocarbons with tion shaft furnace and in the return an oxidizing gases due to the influence of special Mixing device for the gases to be converted catalysts can be accelerated (»steel and a continuously working, indirectly loading and iron ", 1962, pp. 869 to 883). Heated catalytic gas converter provided. Finally, it is also from the USA. patent ? ind, characterized in that between the 45 3 193 378 the attempt became known, with only one Mixing device (68) and the catalyst (98) single continuously operating catalytic gas of the gas converter (38) a device (94) for converting the conversion of gaseous carbon Preheating of the gas mixture is arranged, the hydrogen with part of the exhaust gases of the reducing Contains non-catalytic material, and that the ionic process can be carried out. The problem of Recirculation line (64) for the exhaust gas with the catalyst poisoning through sooting is what you want Avoid reducing gas line (46) for the purpose of Tem- in that very large amounts of temperature setting is connectable (50, 52, 54). additional oxygen in the form of water vapor 7. Apparatus according to claim 6, characterized in that they are added upstream of the gas converter. the characterized in that the catalyst (98) and conversion then happens at relatively lower the non-catalytic material (94) at an indirect 55 temperature. After the conversion and before the heated catalytic tube (44) of the gas converter reduction furnace must have the very large quantities (38) are located. Water vapor is separated from the circuit again 8. Apparatus according to claim 6, characterized in that practically a condensation of the gas mixture leaving in the return line between the converter requires a temperature which is very low at the outlet (24) of the exhaust gas from the reduction 60. The shaft furnace and the mixing device (68) for significantly cooled gas must then be heated up again accordingly in order to have the gases to be converted in the reduction furnace a cooling cleaning device (60) and also a cooling cleaning device. Otherwise bypassing the gas line (72) are provided, which would result in a very poor efficiency in the part of the exhaust gas bypassing the reduction furnace. Both ways prohibit cooling cleaning device burners (40) of the gas - the economic operation of a large system,
converter (38) can be supplied. The present invention is therefore the object 9. The device according to claim 6, characterized in a method of the generic type