WO2020225013A1

WO2020225013A1 - Coke oven device for producing coke, method for operating the coke oven device, and use

Info

Publication number: WO2020225013A1
Application number: PCT/EP2020/061664
Authority: WO
Inventors: Roland Kim; Rafal Grzegorz Buczynski
Original assignee: Thyssenkrupp Industrial Solutions Ag; Thyssenkrupp Ag
Priority date: 2019-05-08
Filing date: 2020-04-28
Publication date: 2020-11-12
Also published as: EP3966298A1; DE102019206628A1; JP2022534669A; BR112021020994A2; KR20210149150A; DE102019206628B4; CN113785033A

Abstract

The invention relates to a coke oven device (10) for producing coke, comprising a plurality of twin heating flues (13) having heating channels, which are each delimited from one another in pairs by a partition (14) and are shielded by two stretcher walls (15) lying opposite one another. In the lower region, at least one inlet from the following group is provided on the bottom (5.4) of each heating channel: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17). At each bottom (5.4), the ratio (y1:y2) of the distance (y1) between the nearest edges of the combustion air inlet (16) and of the mixed gas inlet (17) to the distance (y2) of the inner edges of the partitions (14) is at least 10%. The distance (y1) between the nearest edges of the combustion air inlet (16) and of the mixed gas inlet (17) is at least 50 mm. At least one of the combustion air inlet (16) and the mixed gas inlet (17) is arranged eccentrically at an x-distance greater than a factor of 0.7 of the absolute x-extent of the heating channel between opposite stretcher walls (15). The invention also relates to a corresponding method.

Description

Coke oven device for producing coke and method for operating the coke oven device and use

Description:

TECHNICAL AREA

The invention relates to a device and a method for producing coke with minimized NOx emissions and corresponding uses. In particular, the invention relates to a device and a method according to the preamble of the respective independent claim.

BACKGROUND

The demand for coke ovens worldwide is still high and is estimated to remain high in the future, as described, for example, in the following publication: K. WESSI EPE et al. : Optimization of Combustion and Reduction of NOx Formation at Coke Chambers .... COKE MAKING INTERNATIONAL; 9, 2; 42-53; VERLAG STAHLEISEN MBH; 1997. Even today, despite ever stricter environmental criteria, several hundred coke ovens are built and put into operation. The number of new coke ovens built every year is estimated to be well over 1000 in Asia alone. Nevertheless, it is now well known not only among engineers, but also within society that energy generation using coke ovens is not particularly environmentally friendly. The construction of new coke ovens or the operation of existing coke ovens is therefore subject to increasingly stricter requirements from many sides with regard to minimized emissions, in particular with regard to nitrogen oxides (NOx). In this context, there are numerous efforts to improve the efficiency of coking. The planning and construction of coke ovens must be done a long time ago. In particular with regard to the desired long service life or service life of a coke oven, it is important to know which environmental improvements can be made in coke ovens in the next few years. A targeted pursuit of individual optimization measures is, however, not trivial with regard to the procedural and structural complexity of coke ovens; rather, individuals must Optimization measures are put into perspective and balanced against each other in an overall concept with numerous interdependencies.

At specialist congresses and in specialist magazines, it has been increasingly communicated in recent years that the local environmental authorities in the respective countries as well as on the customer side are already making much stricter requirements with regard to reduced environmental pollution from flue gas emissions or are expected in the near future. With regard to these flue gas emissions, the thermal NO _c formation in the vertical, flue gas-carrying heating flues of coke ovens has proven to be one of the main causes.

The following emission limit values, which were permitted in 2018 or are still tolerated in existing plants, can be mentioned in particular for European territories: 500mg / Nm ³ , corresponding to approx. 250ppm at 5% oxygen 02. However, this limit value has been in place for many years and may be in the near future Future in many countries further degraded. There is therefore interest in significantly falling below this limit value by means of technical measures in the near future.

Nitrogen oxides are released, in particular, by the flue gas specially generated during the combustion of coke oven gas, in particular from a nozzle stone temperature (i.e. a temperature in the exhaust-gas-carrying heating duct on the floor) of approx. 1,250 ° C; this is referred to as the so-called thermal NOx formation. The thermal NOx formation is further promoted or increased exponentially with increasing temperatures, so that the emission of nitrogen oxides is largely determined by the thermal operating conditions of the coke oven in the respective load state. It is therefore also sufficiently known that, in particular in the vertical, flue gas-carrying heating flues of the coke oven, the NOx emissions can be influenced by setting or regulating a specific temperature regime. A furnace operator therefore endeavors or is forced by environmental specifications to keep the temperature in the exhaust gas-carrying heating duct as low as possible, in particular not to rise above 1,250 ° C to let. At the same time, significantly higher process temperatures in the range of 1,250 to 1,320 ° C have become established in plant practice worldwide, as a compromise for not only ecological, but also economical plant operation.

A system operation that is optimized with regard to NOx emissions must therefore be adjusted to a lowered (comparatively low) temperature level in the heating flue. However, this is associated with a decrease in coking output and thus inevitably with a loss of coke production. Example: Instead of 100 ovens, only approx. 95 to 98 ovens need to be built at a higher permissible operating temperature, corresponding to a savings in equipment of 2 to 5 percent (lower investment volume, up to 5% lower system costs, e.g. in relation to an investment volume of 100 to 800 million euros).

In order to reduce the NOx emissions, because of these uneconomical power losses, attempts are made only very reluctantly to maintain a reduced temperature level during the coking process or to avoid local temperature peaks in the heating flues. Rather, as long as it remains legally permissible, it is accepted that the NOx emissions will remain disadvantageously high. The furnace operator knows, however, that if it were possible to keep the heat energy input constantly high at a comparatively moderate, reduced temperature, this would have a positive effect on the lowest possible NOx emissions with a comparable output.

Coke ovens can be subdivided into vertical chamber ovens and horizontal chamber ovens, in particular with regard to the direction in which the coke is pushed out. In horizontal chamber furnaces, coking takes place in batches: After coking, the coke is expressed in a horizontal direction (batch operation). In contrast to this, in vertical chamber furnaces, the coal is continuously fed in and out vertically (Conti operation). The present invention particularly relates to horizontal chamber furnaces. Coke ovens are optionally heated by a mixed gas generated from blast furnace top and coke oven gas or by pure coke oven gas (coke oven gas heating usually in less than 10% of the annual operating time). Due to the high proportions of hydrogen and carbon monoxide and the resulting high flame temperature, the flue gas generated by coke oven gas combustion is particularly contaminated with high NOx proportions. This is one of the reasons why many of the previous measures were primarily aimed at reducing NOx emissions, especially when heating coke oven gas. The following is a tabular overview of the element distribution (in% by volume) of the respective type of gas, whereby this information is based on mean values that have been determined over several years, in particular by the owners of the intellectual property of the present invention:

Trace elements in all three types of gas: eg ammonia, noble gases; Blast furnace gases are produced during iron ore smelting processes in blast furnaces and are also referred to as "low calorific value" gases, as they typically have only a low heat content (lower calorific values between 2,700 and 3,800 kJ / Nm3). Blast furnace gases are comparatively inexpensive. Coke oven gases are during the Coking process in coke ovens and have high heat contents (lower calorific values between 15,900 and 19,500 KJ / Nm3). They are therefore also referred to as "strong gases". Coke oven gases are comparatively expensive.

For economic reasons, both types of gas are usually used in practice in such a way that they are mixed beforehand in a ratio of 87 to 97% by volume of blast furnace gas to 3 to 13% coke oven gas and fed to the coke ovens for combustion. This mixed gas is usually used more than 90% of the year as heating gas in the coke ovens. Other types of gas, which are sometimes added as alternative components to the starting gas types (blast furnace gas, coke oven gas) (the resulting gas mixture is usually referred to as “coke oven mixed gas”), are known as “converter gas” or “generator gas”. “Converter gases” mostly come from the steel-making industry. “Generator gases” are generated in many branches of industry, mostly in coal-processing processes. The present invention relates primarily to the use of mixed gases in the narrower sense, that is to say mixed gas without a predefined proportion of “converter gas” or “generator gas”.

With reference to the table above, hydrogen is assessed as the component whose combustion is associated with the highest local flame temperature and thus with the highest thermal nitrogen oxide formation. Coke oven gas has a considerably larger proportion of hydrogen than blast furnace gas. Therefore, the coke oven gas heating causes particularly great difficulties in plant operation with regard to emission limit values.

It is worth mentioning that there are also coking plants with so-called "strong gas ovens", which cannot be connected to a blast furnace, especially due to their isolated geographical location, and which use the gas generated in the coke ovens during coal pyrolysis for heating for 100% of the operating time ( must), whereby the gas is usually returned to the ovens in a so-called secondary recovery system after appropriate removal of impurities or valuable substances becomes. However, these ovens are not designed for standard "mixed gas heating".

The oven chambers of the coke ovens described above usually (situation in 2018) have a height in the range of 4 to 8.5 m, the preferred height of the oven chambers or heating channels also being determined by the operating mode. The height has an influence on the pressure difference that is established in the heating duct. If a large pressure difference is required, a large height must be selected. It can be assumed that the temperature should be kept as constant as possible over the entire height of the furnace chamber, because only then should it be possible to set an efficient operating state without an excessive increase in NOx emissions. The temperature gradient should, if possible, be significantly smaller than 40K or 40 ° C, in particular at a temperature in the furnace chamber in the range from 1,000 to 1,100 ° C. Such a small temperature gradient also favors optimal coke quality. A temperature maximum well above the average temperature would promote thermal NOx formation. A coke oven can then be operated with a particularly optimal compromise between high output and low NOx emissions, if the temperature distribution is very homogeneous and if the temperature in the entire furnace chamber remains just below the temperature from which thermal NOx formation occurs or is fanned exponentially.

Design variations are associated with great effort in coke oven construction. The effects of individual optimization measures must be predictable as cost-effectively as possible before the measures can be implemented in furnace construction. The simulation of operating states is a useful tool to better assess the effects of individual optimization measures. A coke oven, however, is a comparatively complex system, so that even purely computer-aided simulations require a corresponding effort. For example, a new design with a new type of gas routing can mean a computational effort (even with the technological possibilities in 2018) of several weeks per calculation, so that even with purely electronic / computer-aided simulations a Workload of several years (e.g. with over 100 required variations) may arise. Not only must new measures be tested on a technical scale on the completed coke oven with limited possibilities, but also a simple constructive measure must first be checked under numerous aspects for cost reasons before this measure can be examined in more detail by simulations. As a result, constructive variations on existing furnace designs are only stimulated, checked and experimentally verified in a very moderate, conservative way.

Measures that have so far been tried and tested directly on the coke oven or on its structural design, which should also be effective in the performance-optimized operating mode, are usually the internal pressure difference-driven or temperature and density differences-driven flue gas return from the downward into the upward flow of the heating flue (internal circulation of a partial volume flow of the Flue gas, so-called circulating flow), and / or the gradation of the combustion air, i.e. the introduction of combustion gas from partition walls or binder walls in different height positions into the heating flues. The grading of the combustion air takes place in particular with regard to the following criteria: the maximum

Gas collecting space temperature in the adjacent furnace chamber above the coal charge must / should e.g. be less than 820 ° C; the ceiling surface temperature must e.g. be less than or equal to 65 ° C if possible; the temperature difference inside the furnace chamber wall must e.g. be less than or equal to 40K, in particular between the height positions 500mm above the furnace base / burner level and 500mm below the upper edge of the furnace chamber.

Circulating current (partially at only one end of the heating channel or completely in a circle) is usually implemented in so-called twin heating flues. Heating flues or heating ducts arranged in pairs next to each other, especially in a vertical orientation, are coupled to one another in that the gas from the flamed heating duct is returned to the non-flaming heating duct, be it only at an upper / lower reversal point, or be it both above and below below. In the case of a horizontal chamber furnace, approximately 24 to 48 heating channels can be provided in a row next to one another, i.e. approximately 12 to 24 pairs of twins, as seen in the push-out direction. An optionally realizable circulating current can develop autonomously due to the pressure differences, i.e. solely due to temperature and density differences in the two respective twin heating flues, i.e. without additional active flow control or support. In other words: Constructive design variations are also limited by the sensitive (thermal) equilibrium, which has to be achieved by means of pressure differences.

The optimization of circulating current, especially for the purpose of homogeneous heat distribution, began as early as the 1920s on an industrial scale. Since the 1970s, the effects of circulating current flow on NOx emissions have also been examined in more detail / systematically.

In heating ducts in pairs (twin heating flues), the mean nozzle stone temperature must be controlled or limited, and must be kept at a moderate level (e.g. at a temperature of more than 2000 ° C for high-gas heating, below 2000 ° C for mixed gas heating) in particular by lowering the local flame temperature a nozzle stone temperature of 1240 to 1300 ° C). Effect: control of NOx emissions. The flame temperature with mixed gas heating is e.g. in a range from 1,500 to 1,700 ° C, in particular at about 1,600 ° C.

For example, the following arrangement (height position) of a lower passage between paired heating channels can be mentioned: between 0mm (i.e. directly at the level of the burner level) to 300mm above the burner level. The cross-sectional area of the passage is usually specified by a layer height (or width of the layer) of approx. 110 mm to 150 mm. If necessary, the lower passage can be closed in the arrangement on the floor by means of a roller, which can be rolled on the burner level in front of the passage. The passage is advantageously realized by means of a recess in a wall layer (gap or missing stone). Insofar as a single passage is mentioned in the present description a pair of passages can also be meant, which are arranged in pairs in the same height position.

The burner level is to be understood as the level at which the

The inlet of the inlets into the heating flue is structurally provided, and based on which height level a height variation can optionally be realized within certain limits by means of extended inlet nozzles, in particular up to 1,000mm above the burner level. This can be distinguished from furnace types which are referred to as step gas furnaces, and in which at least one inlet is only provided at a height well over 1,000 mm above the burner level.

The height position of a lower passage or a pair of lower ones

Passages can also be arranged up to a height of 1,000mm above the burner level.

The height position of a lower passage or a pair of lower ones

Passages can also be arranged below the burner level, in particular up to 500mm below the burner level.

A partial volume flow of the flue gas, which is usually led back into the flamed heating duct, amounts to e.g. 30 to 45% of the total flue gas volume generated in the upward flow through the heating duct. An example of this arrangement of twin heating flues with circulating current is the so-called Combiflame heating system, which has been established since the late 1980s. There is a combination of air staging and circulating current flow. Up until the mid-1980s, there was either only air staging (Otto system) or only circulating current flow (Koppers system).

As indicated above, the combustion can also be staggered in that gas or air is fed into the respective heating flue via at least one step air duct in at least one height position above the burner level (floor), or the same Exhaust gas is discharged. The staged combustion can be combined with the circulating current flow.

If the measures taken directly on the coke oven are specifically considered, i.e. measures to optimize thermal engineering, in particular through an optimized manner of media routing, then the structural design of the coke oven and the associated stability of the coke oven are of great relevance, especially the structural design of the individual Walls of a respective furnace chamber and the respective heating flue (rotor walls, partition walls). Small measures on the structural design can have major effects on the temperature equilibrium and the coking process. However, each measure may also have very disadvantageous side effects to be avoided, for example on the statics of the heating walls, on the flow resistance, or the flow velocities and temperature profiles that ultimately arise. It is therefore to be expected that changes to the structure described in more detail below can only be made within a narrow tolerance range. In particular, the person skilled in the art is also faced with the task of not risking any weakening of the heating wall assembly through new measures. Because, depending on the operating status, high lateral forces can act on every wall. For example, after about 75% of the cooking time, a high lateral internal pressure (driving pressure of the charcoal charge) arises, especially on rotor walls with a pressure maximum at a height of approx. 1 m above the burner level, which driving pressure can even lead to joints in the masonry of the partition wall Widen the furnace chamber, possibly with the effect that undesired bypass flows (in connection with coke oven gas overflow and the associated CO formation) arise between individual heating flues and (neighboring) furnace chambers. The equilibrium of the gas mixture is also disturbed as a result; in particular, only an insufficiently high amount of air is available for additional gas quantities to be burned in the heating duct. Different filling times, for example each offset by several hours, also lead to different lateral forces in the respective walls in the adjacent furnace chambers. The stability of the furnace is therefore also important for the previously described measures necessary to reduce emissions are a high priority. High stability is usually achieved by a tongue and groove arrangement of the stones. This construction, which is very flexible at the same time, is also preferred in terms of tightness in order to avoid bypass flows and pre-combustion. The person skilled in the art has no reason to deviate from a robust construction that is as flexible as possible and at the same time as stable as possible without any particular reason.

In the case of a battery with several furnace chambers, e.g. at least 15 to a maximum of 90 furnace chambers, the furnace chambers are separated from gas-carrying heating channels by rotor walls, in particular on a relatively narrow end face of the respective channel, in particular by two opposing rotor walls extending along the entire respective furnace chamber. The individual heating channels are sealed off from one another by what are known as truss walls (partition walls), which in particular extend orthogonally to the two rotor walls between the rotor walls. A truss wall seals off two ducts from one another, or two truss walls seal off a twin heating duct pair from an adjacent further twin heating duct pair. A respective heating channel is thus delimited by two runner wall sections and two truss walls. In the push-out direction (depth y) a respective heating channel is e.g. approx. 400 to 550mm long or deep (middle to middle). A runner wall thickness is e.g. in the range from 80 to 120mm. A truss wall thickness is e.g. in the range from 120 to 150mm.

The term “truss wall” has established itself in common parlance. In the present description, this term is used synonymously with the term “partition”, in particular to clarify that a runner wall and a truss wall / partition wall can be produced in the same construction, namely by stones lined up on their narrow sides. The “runner wall” of a horizontal chamber furnace can also be described as a longitudinal wall arranged lengthways in the push-out direction, and the “truss wall” can also be described as a transverse (partition) wall arranged transversely to the push-out direction. Combustion air openings and mixed gas openings are provided on the underside of each heating channel, the function of which can be selected or adjusted depending on the type of heating (mixed gas or coconut oven gas heating). A coke oven gas opening opens into the heating channel at the bottom. In the case of circulating current routing, a pair of heating channels are coupled to one another via exhaust gas recirculation openings arranged on the underside of the furnace chambers, so that a twin heating duct with circulating current routing is formed. The volume flow through the exhaust gas recirculation openings can optionally be regulated, in particular by means of an adjusting roller arranged on the floor in the burner level and displaceable there. Step gas channels are provided in the truss walls, which feed combustion air (step gas) into the furnace chamber at one or more height positions (air step or truss wall opening). A common ratio of the volume flows introduced into the furnace chamber can be mentioned: approx. 30% through the combustion air inlet on the floor, approx. 30% through the mixed gas inlet on the floor, and approx. 40% through the at least one step gas inlet (binder wall opening). This ratio can also be set for the discharge of the gases from the furnace chamber, depending on the performance requirements.

Above the exhaust gas inflection point (recirculation passage), a bypass flow in the form of a heating differential can be formed in order to adapt coking parameters. The bypass flow can be sealed off from the heating flues via a particularly horizontal wall or ceiling, in which ceiling passages are provided that can be covered, for example, by means of slide blocks or adjusted with regard to the cross section.

The aforementioned publication by K. WESSI EPE also considers in particular measures on ovens with twin heating flues, whereby it was already worked out in the 1990s that the so-called circulating current arrangement can provide advantages with regard to the lowest possible NOx concentration. As prior art, the patent specifications DE 34 43 976 C2 and DE 38 12 558 C2 can be cited as examples, in which the aspect of an optimal circulating flow rate and a reasonable height position for the gradual introduction of combustion air is discussed, in particular using the example of the Koppers circulating flow furnace . It also mentions that the return of flue gas at a height in the area of the heating flue bottom enables the temperature in the respective heating flue to be lowered, with the effect of reducing NOx emissions.

The laid-open specification CN 107033926 A from August 2017 describes an arrangement with twin heating flues with graded introduction of combustion air and with circular flow openings, which are arranged on both sides to the side of the stepped air duct.

Experiments have also been carried out with a certain type of gas guide components or packing in order to be able to influence the heat distribution in the coke oven. For example, in patent DE 39 16 728 C1, heating rooms (heating flues) are provided with internals in the form of permeable honeycomb bodies or honeycomb grids or spherical beds, with certain types of flue gas routing being said to be advantageous in some sections. The aim is to improve the flow conditions in the heating rooms, and it is also proposed to supply combustion air at different height positions.

Experiments have also been made with certain coatings to effectively dissipate or reflect heat energy from internal surfaces.

The measures described above directly on or in the coke oven or heating flue can be referred to here as primary measures, i.e. measures that are intended to counteract the primary NOx formation mechanisms in the heating flue (in particular internal flue gas recirculation or circulating flow, grading of the combustion air). With all the measures described above, it must be noted that the ovens described here are usually operated with self-ignition (especially at over 800 ° C), see above that the corresponding measure for cooling or lowering the gas temperature can only take place under narrow boundary conditions or only in a narrow temperature range, in particular in order to avoid the combustion going out.

Furthermore, so-called secondary measures have already been tried out, which can be carried out downstream of the coke oven in downstream system components, for example by using selective catalysts in the chimney (SCR or DeNOx) to reduce the NOx content in the flue gas before it is evacuated into the atmosphere, or the external recirculation of already evacuated flue gas from the chimney back into the coke oven. Regardless of how effective these downstream measures are, in many cases they fail because of extremely high costs (up to 50% of the total investment for the entire coke oven) or because of additional maintenance costs. While these measures are effective, in many cases they are too costly.

Patent application DE 40 06 217 A1 can also be mentioned, in which the combination of several measures is described including measures on regenerators in the central part of the furnace and measures for external flue gas circulating flow, with the aim of homogeneous heating conditions and low NOx emissions even with high oven chambers.

Last but not least, measures of a chemical, reactive nature such as introducing CH4 gas or increasing the humidity by injecting water or injecting ammonia have been considered. The injection of water or steam is not possible at any point in the furnace chamber, but in particular only centrally at a middle height position; this measure also has adverse effects on the (silicate) materials used. Increasing the regenerative preheating temperature of gas and air is a measure that is now considered to be exhausted and uneconomical.

In any case, in 2018 it still seemed inconceivable that the requirements described above would be combined with the internal, primary measures, either alone or cumulatively, can be met. Lowering the NOx emissions by a considerable factor, in particular by a factor in the range from 2 to 5, should therefore not be feasible, in particular not down to a range below 200 mg / Nm ³ or below 100 mg / Nm ³ , at least not below an acceptable level Effort, so not in an economical way.

In spite of the concerns expressed above, the present invention is aimed at optimizing coke ovens by measures directly on the coke oven or on its structural design, in particular by measures on the established heating system with heating flues with at least one recirculation opening, in particular with circulating current flow, in particular by possibly the option to create the ability to operate the coke oven in a performance-optimized operating mode without any downstream system components (only internal, primary measures to reduce NOx). A great potential for improvement can be hoped for here, with great advantages also for the furnace, and thus also with good chances for the technical concept to be implemented on the market.

Previous measures are primarily aimed at lowering the disproportionately high NO formation when heating coke oven gas, i.e. when heating with pure coke oven gas (not with mixed gas) - with mixed gas heating, these measures may tend to be less effective. Many of these measures may even have a negative effect on NOx formation when heating with mixed gas. Usually, however, coking plants are primarily operated by mixed gas heating; It is estimated that mixed gas heating is the dominant heating method in more than 90% of the applications or in more than 90% of the operating time (coke oven gas heating, e.g. only in emergency situations or during maintenance work). Theoretically, the measures aimed at coke oven gas heating should therefore be approx. 10 times more effective than measures for mixed gas heating in order to enable the same total NOx savings over the life of the oven. Many aimed at coke oven gas heating Measures also have the disadvantage of increased pressure losses in the furnace, which means that a negative pressure source with increased power must be included in the system planning.

Even more recent measures to reduce disproportionately high NO formation have so far mainly concerned coke oven gas heating. There is therefore interest in a NOx-related optimization of existing heating methods as well as the heating flue design especially for the heating method of mixed gas heating, which has so far been neglected in many cases. The known primary NOx reduction technologies can of course be taken into account first of all.

DESCRIPTION OF THE INVENTION

The object of the invention is to provide a coke oven device and a method for operating the coke oven device, with which NOx emissions can be kept low, especially for mixed gas heating, or can be minimized in existing or new systems even when operating at full load, the coke oven device should enable an advantageously low NOx emission level, preferably without downstream system components. In particular, the object is to provide a coke oven device and a method for operating the coke oven device, with which the NOx emissions can be reduced, especially in the case of mixed gas heating, by internal measures in the heating flues, in particular exclusively by internal primary measures. Such measures should preferably only require minimally greater pressure losses, especially for mixed gas heating; In particular, any increases in pressure loss in the furnace that are required by these measures should be in a non-critical range of less than 50 Pa. Ultimately, such measures, especially for mixed gas heating, should also be compatible with any measures for coke oven gas heating, or at least not have a particularly negative impact on the operating mode of coke oven gas heating, even if coke oven gas heating only takes place for a small proportion of the annual operating time. This would enable a comparatively flexible mode of operation, i.e. a very variable furnace for a wide range of tasks. This object is achieved according to the invention by a coke oven device for producing coke by coking coal or coal mixtures, at least with mixed gas heating and optionally also with occasional coke oven gas heating, the coke oven device being set up for minimized nitrogen oxide emissions through internal thermal energy compensation by means of the steel mill's own gases (in particular blast furnace gases) and coke oven-own gases G1, G4, G5 by measures internally on the coke oven device, with a large number of twin heating flues each with a heating duct flamed with gas and a heating duct flowing downwards through which exhaust gas flows, which heating ducts are separated from each other in pairs by a partition wall (also known as a binder wall) are sealed off from a respective furnace chamber by two opposing rotor walls, the paired heating ducts fluidically by means of at least one upper coupling passage and also in the middle ls at least one lower coupling passage each for internal exhaust gas recirculation are coupled to one another on at least one circular flow path, with at least one inlet from the following group being provided in the lower area at the bottom of the respective twin heating flue: coke oven gas inlet, combustion air inlet, mixed gas inlet; where on the respective floor the ratio y1: y2 of the distance y1 between the facing edges of the combustion air inlet and the mixed gas inlet to the distance y2 of the inner edges (inner surfaces) of the partition walls of a respective heating duct is at least 10%, the distance y1 between the facing The edges of the combustion air inlet and the mixed gas inlet are at least 50mm, with at least one of the combustion air and mixed gas inlets being arranged eccentrically at an x-distance greater than a factor of 0.7 of the absolute x-extent of the heating duct between opposite rotor walls. This enables a reduction in NOx emissions by means of internal thermal measures. According to the invention, the combustion air inlet and mixed gas inlet are arranged at a relatively large distance from one another in the y-direction, with a relative Minimum distance with respect to the entire y-extension of the respective heating channel is defined. According to the invention, an absolute minimum distance is also defined (yl min = 50 mm). This enables an advantageous influence on the temperature and flow profile. The minimum distance y1 is, for example, in the range from 60 to 220mm. The distance y2 between opposing partition walls is, for example, in the range from 250 to 400mm.

The absolute position of the mixed gas inlet can e.g. can also be defined by a minimum distance to the runner walls in the y-direction, and / or by a minimum distance to the partition walls, in particular e.g. > 10mm between the outer edge of the mixed gas opening and the inner edge of the partition wall (binder wall). The distance between the mixed gas opening and the coke oven gas nozzle (relative position) can be in particular at least 100 mm in the x direction.

According to the invention it has been shown that an economically favorable process temperature above 1,250 ° C. and thus a high system performance while maintaining the strict limit values described above based on geometric measures at the bottom of the heating flues can be ensured with good effect. Any increase in pressure losses can also be kept within comparatively moderate limits. Due to the relative or absolute positioning of the mixed gas inlet according to the invention, the desired temperature distribution can also be realized in a particularly effective manner.

The combustion of mixed gases, which was previously considered less critical due to the low hydrogen content, has not yet been the main subject of nitrogen oxide-reducing further developments in vertical heating duct designs in composite coke ovens. The mode of operation with mixed gas heating, however, often affects a considerable proportion of the absolute operating time of a furnace. According to the invention, particularly advantageous NOx-reducing effects can be implemented especially in the case of mixed gas heating. An increase in the absolute distance between the outlet positions for the combustion media "bottom air" and mixed gas ", particularly in connection with a relative minimum distance with respect to the entire extension of the heating channel in the y-direction, enables the furnace to be designed independently of the specific volumes or power ranges of the furnace.

As far as the respective function of the individual inlets is concerned, this can also be described in terms of different modes of operation: For a composite furnace connected to a steelworks, two openings or inlets are provided on the boiler floor when mixed gas is heated, namely an inlet for mixed gas and an inlet for ( Combustion) air. For a composite furnace with coke oven gas heating, the mixed gas ducts are also pressurized with air. For a furnace that is designed exclusively for coke oven gas heating (so-called strong gas furnace), only one air inlet is required (no mixed gas inlet). The latter constructive design is to be understood as a special case.

In the case of pure mixed gas heating, the arrangement of the coke oven gas inlet is comparatively unimportant; the relative arrangement of the coke oven gas inlet can therefore be varied to a greater or lesser extent depending on the application, be it in the longitudinal and / or in the transverse direction. A sensible compromise then also depends on the expected operating times for the respective type of heating. By means of the absolute and relative arrangement according to the invention of the inlets for combustion air and mixed gas, a good compromise with minimized NOx emissions can be provided for a large proportion of the absolute operating time for various different designs of furnaces.

A comparatively large distance between the two inlets for combustion air and mixed gas relative to the coke oven gas inlet can be assumed to be useful or even optimal; However, it has been shown that the effects according to the invention can also be implemented largely independently of the relative arrangement of the coke oven gas inlet. This also delivers in the context of the present Invention further constructive or process-related variables (or degrees of freedom) for adapting a furnace to specific applications.

For example, a distance y1 in the range from 100 to 300 mm is provided. For example, a ratio y1 / y2 in the range between 30 and 60% is selected (or 0.3 and 0.6). The ratio y1 / y2 can also be significantly greater, for example up to 90% (or 0.9). The ratio y1 / y2 is preferably in a middle range below 0.5. This has proven to be advantageous in particular with regard to a temperature distribution in the vertical direction.

It has been shown that a variation of the distance y1 can be used as an effective measure for NOx optimization. In particular, a positive effect with the size according to the invention or the range according to the invention of the distance y1 on NOx formation could be demonstrated in a systematic manner. So far, the furnace manufacturer has refrained from varying the distance y1. In particular, this distance was not identified as a measure for NOx savings. There was therefore also no reason for such a purposeful variation of the distance y1, in particular since a distance variation at first sight does not allow any systematic conclusions to be drawn about the NOx emissions.

The x position of the combustion air and mixed gas inlets can in particular be defined in relation to their center points. In particular, at least one of the combustion air and mixed gas inlets, in particular its center point, can be arranged eccentrically at an x distance greater than a factor of 0.8 of the absolute x extension of the heating channel between opposing rotor walls. This degree of eccentricity in the x-direction can also ensure advantageous primary mixing of the gases before combustion.

Gases produced in the steelworks are to be understood in a broader sense as the gases produced in the steelworks, including what is known as converter gas. Strictly speaking, converter gas is not used in pig iron production Assigned to the blast furnace, but rather to the underlying process chain of actual steel production in the steelworks. The term “steel mill's own gases” can in particular also include hydrocarbons or natural gas, in particular as mixture components.

A comparatively small ratio y1: y2, in particular below 15%, can be advantageous in particular for rather large systems.

The arrangement according to the invention enables e.g. also comparatively moderate flame temperatures with a comparatively high nozzle stone temperature, in particular a flame temperature with mixed gas heating of a maximum of about 1,600 ° C with a nozzle stone temperature of at least 1,300 ° C or 1,320 ° C.

It has been shown that the arrangement according to the invention, both in the case of a constructive configuration of the twin heating flues in the manner of a "back-to-back" heating (in each case vertically identical flow direction in adjacent twin heating flaps) and in a constructive configuration of the twin heating flues in the manner a forward flow (vertically opposite flow direction in adjacent heating flues) can be realized. In the case of “back-to-back” heating, a single lower recirculation passage or a plurality of recirculation passages, in particular in pairs, can be provided. In this case, lower recirculation passages are preferably provided in pairs in the forward flow.

In the operating mode "forward burning", for example, the heating flues with the odd number # 1, # 3, # 5, # 7, # 9, ... (n + 2) burn, or after the heating changeover, the even heating flues with the numbers # 2, # 4, # 6, # 8, .... (n + 2). In particular, at least one recirculation opening is provided in each binder wall. In this type of furnace, at least two lower recirculation openings are preferably provided which enclose or delimit or surround the step air duct in the binder wall. It has been shown that by means of the recirculation openings flowing flue gas can at least partially form an inert intermediate layer in the horizontal direction to at least one of the admitted media (gas and / or air). It has been shown that this can delay the combustion in the vertical direction, which can have a favorable effect on the temperature distribution. For example, there are at least two recirculation openings per layer in each binder wall. A first pair of recirculation openings is preferably located in one of the lowest five truss wall layers. In particular for reasons of stability, further openings are only provided in the next but one layer above (e.g. vertical layer number 3), which can be arranged in particular parallel (symmetrically) to layer number 1.

In the “back-to-back” operating mode, heating flues number # 1, # 4, # 5, # 8, # 9, ... (starting with 1, where n + 3 / n + 1), or after the heating changeover burns the heating flues number # 2, # 3, # 6, # 7, # 10, # 1 1, ... (starting with 2, where n + 1 / n + 3). It has been shown that by means of the flue gas flowing back through the recirculation openings, a combustion-inert intermediate layer to at least one of the admitted media (gas and / or air) can be formed. In particular, at least one recirculation opening is provided in every second binder wall. For example, a (in particular comparatively large) individual recirculation opening is provided in the middle of the binder wall. For example, the step air duct and recirculation opening (s) are only located together in the corresponding truss wall. At least one further recirculation opening is preferably provided in at least one of the wall layers located above.

The respective arrangement of the at least one recirculation passage can be chosen largely freely. Optionally, its arrangement can be defined relative to the arrangement of the further inlets. Optionally, an x-coordinate and / or a z-coordinate can be specified for the arrangement of the center point of the recirculation passage. For example, the (lowermost) recirculation passage is or are the (lowermost) recirculation passages in one Height position less than 2m above the ground. According to one variant, recirculation passages are provided in pairs for each height position, in particular in a symmetrical arrangement with respect to the x-extension of the heating flue. For example, one or two pairs of recirculation passages are arranged in like height positions on the same x-coordinate as at least one of the air and mixed gas inlets.

It has been shown that it is advantageous to arrange at least one of the air and mixed gas inlets at a comparatively small x-distance to the closer wall of the rotor, in particular a maximum of 50 mm or even a maximum of 20 mm or 10 mm.

Furthermore, it has been shown that the air and mixed gas inlets can optionally be arranged completely overlapping in the x direction, that is to say without an offset being realized or without the geometrically smaller inlet protruding beyond the geometrically larger inlet in the x direction. Furthermore, it has been shown that the air and mixed gas inlets can optionally also be arranged without any overlap in the x direction, that is to say with such a large offset that an overlap in the x direction cannot be determined.

In particular, only one of the types of inlets described here is provided for each heating flue, i.e. only one combustion air inlet and only one mixed gas inlet.

It has also been shown that the combustion air can preferably be supplied in stages, in particular for the purpose of two-stage combustion over the entire height of the respective heating flue. Corresponding bulges or inlets for step air can be arranged in an individually optimized manner depending on the application.

According to one embodiment, the ratio y1: y2 is at least 25%. This also enables good distribution or thorough mixing of the gases over the entire extent of the heating channel. According to one embodiment, the distance y1 is at least 100 mm, for example at least 150 mm, for example 200 to 250 mm. This allows the gas flow paths to be set and regulated more individually.

According to one embodiment, the ratio y1: y2 is at least 35%, in particular a maximum of 50% or a maximum of 60% or a maximum of 70%. It has been shown that, starting from 10% or 15%, the distance y1 can be further increased or also maximized without this having to be associated with noticeable disadvantages with regard to the NOx emissions or with regard to further operating parameters of the furnace. This opens up further constructive degrees of freedom.

According to one embodiment, the distance y1 is at least 150mm or at least 200mm. In this way, an advantageous relative arrangement can be ensured even with comparatively large-volume ovens.

According to one embodiment, the distance y1 is a maximum of 350 mm or a maximum of 375 mm. It has been shown that distances y1 greater than 400 mm could be associated with disadvantages with regard to further process parameters of the furnace. According to the invention, it is recommended to limit the distance to an upper limit below 400mm.

According to one embodiment, the distance y1 is in the range from 200mm to 300mm or in the range from 150mm to 250mm. This range or this distance spectrum has proven to be particularly advantageous in many tests. A more exact distance specification can be defined depending on the overall extent of the furnace or the heating channels.

The distance in each heating flue of the coke oven device is preferably the same. An analogous construction or symmetrical design with regard to all heating flues also has thermal and structural advantages. A comparatively large ratio y1: y2, in particular over 25% or even over 35% or 40%, can be advantageous in particular in the case of rather small systems. According to one embodiment, the geometric centers of the inlets of the respective heating flue and of the at least one lower coupling passage, in particular one of several lower coupling passages further away from the combustion air and mixed gas inlet, define a triangular or square arrangement (polygonal arrangement), the area of which (A) in plan view is at least 50 cm ² , in particular at least 200 cm ² or at least 300 cm ² or at least 500 cm ² or at least 700 cm ² or at least 900 cm ² , in particular between 1,000 cm ² and 1,350 cm ² . This enables a good distribution of material and energy flows largely independent of the individual structural features of the respective furnace. It has been shown that particularly strong effects can be achieved from a surface area of 200 cm ² . The effects can be further intensified in particular from 300cm ² or 500cm ² .

According to one embodiment, the triangular or square arrangement has an area (A) in plan view of a maximum of 2,000 cm ² , in particular a maximum of 1,800 cm ² or a maximum of 1,500 cm ² or a maximum of 1,300 cm ² or a maximum of 700 cm ² , in particular between 1,000 cm ² and 1,300 cm ² . These upper limits can characterize an advantageous range which can still be implemented in a justifiable manner in terms of construction. It has been shown that the surface area must not be too large, in particular in order to be able to avoid side effects that may have adverse effects, depending on the furnace configuration. A surface area of less than 1,500 cm ² can favor a particularly large number of furnace configurations, but the upper limit can also be greater than 1,500 cm ^2, especially in the case of very large or high furnace chambers. The respectively preferred lower / upper limit can also be dependent, for example, on the furnace chamber height, such as in connection with the Description of the figures is explained in more detail. In particular, the lower limit for furnace chambers with a height greater than seven (7) meters can be increased by 100 or 200 cm ² .

A relative triangular or square arrangement, with corner points defined by geometric centers of the mixed gas and combustion air inlets and the (more distant) lower recirculation passage (relative position geometry relative to one another) also provides the advantage of the best possible use of the available (combustion) space, in particular such that the mixing ratio of the gases can advantageously be set. In particular, an advantageous distribution of the material and energy flows can be ensured with a comparatively large surface area. In particular, thanks to the widely distributed arrangement of the inlets on the available base area, combustion which is particularly advantageous in the vertical direction (in particular strongly delayed) can be ensured for the usual types of heating (mixed gas or coke oven gas heating).

In particular, the corner points of the triangular arrangement are defined by the geometric centers of the mixed gas and combustion air inlets and by the center of the (more distant) lower recirculation passage, i.e. offset inward with respect to an exit plane from the corresponding partition.

According to one embodiment, the edges of the combustion air inlet and the mixed gas inlet facing the rotor walls are arranged on the respective floor at different distances x1, x2 from at least one of the two opposite rotor walls of the respective twin heating flue, in particular with a difference in distance of at least 10mm or at least 50mm. The offset in the x-direction also enables an additional differentiation with regard to temperature and flow distribution.

It has been shown that the distances x1, x2 to the two rotor walls can be set comparatively freely. The respective openings / inlets can also be of different sizes both in the x and in the y direction have a different geometry. The inlets can be offset in the x-direction even with the same cross-section.

According to one embodiment, the cross-sectional area is

Combustion air inlet and / or the mixed gas inlet on the respective floor at least 30cm ² or at least 50cm ² . This can also further promote a flattening of temperature peaks.

According to one embodiment, the cross-sectional area is

Combustion air inlet and / or the mixed gas inlet maximum 500cm ² or maximum 400cm ² . These comparatively large areas also favor a large-area heat input.

According to one embodiment, the respective inlet cross-sectional area is comparatively large, in particular larger by a factor of 2 to 3 than the usual cross-sectional area contents. In the prior art, only significantly smaller cross-sectional areas are described, for example in the range from approx. 50 to 100 cm ² . For example, the aforementioned publication by K. WESSIEPE describes dimensions of 51 mm x 144 mm, i.e. only approx. 75 cm ² .

In particular, a connecting opening for the exhaust gas or flue gas flow reversal (passage) can also be designed with a passage area of at least 500 cm ² . Last but not least, this also enables unwanted ones

To keep increases in pressure loss in the heating channel in an acceptable and also economically advantageous range, in particular at less than 50 Pa. Last but not least, this also saves an increased or additional vacuum source. In other words: an increase in the exhaust chimney and / or an additional fan is not necessary.

According to one embodiment, the cross-sectional geometry of the combustion air inlet and / or the mixed gas inlet is rectangular or elliptical or round. The Geometry can, for example, also be optimized with regard to design specifications or stability aspects. In particular, a further optimization can also be carried out by means of adjustable outlet openings (inlets) for the gases, in particular by means of slide blocks.

Further measures can achieve further advantageous effects. In particular, based on a variation in the position of the inlets with regard to an asymmetrical arrangement (at least for soil air and mixed gas), a further optimization can take place, e.g. by non-parallel arrangement on the floor in relation to the runner wall.

It has been shown that by means of measures according to the invention, particularly with mixed gas heating, a reduction in NOx formation or NOx emissions by at least 15% compared to the actual state (state of the art) can be achieved. At first glance, this percentage may not seem revolutionary, but it can justify economic operation, especially if economic functionality was previously not possible due to emission requirements and a restriction to a certain maximum temperature.

According to one embodiment, the cross-sectional area of the combustion air inlet and / or the mixed gas inlet is designed to be adjustable in terms of geometry and / or size on the respective floor, in particular by means of at least one displaceable valve block and / or by means of at least one exchangeable / removable nozzle. This allows further optimizations to be implemented, especially during operation (fine adjustment).

According to one embodiment, the at least one upper recirculation passage coupling the two respective heating channels of a respective twin heating flue in the upper area is set up for the mutual transfer of gases, the recirculation passage having a cross-sectional area of at least 250 cm ² , in particular of a maximum of 1200 cm ² or a maximum 1000cm ² . Through this optimization can also take place in a comparatively flexible manner thanks to comparatively large passage openings.

According to one embodiment, the paired heating channels are fluidically coupled to one another by means of at least two lower coupling passages, the combustion air inlet being arranged at least approximately in the same x-position as the corresponding lower coupling passage, in particular with the respective center point of the combustion air inlet and the corresponding one Passage in an arrangement on the same x-coordinate. This favors a thorough mixing of the recirculation gas and combustion air, in particular before combustion, in a particularly advantageous manner.

According to one exemplary embodiment, the combustion air inlet and the mixed gas inlet are arranged offset in the x direction with respect to the opposite rotor wall. This variation can promote good mixing. Different geometries and / or cross-sectional areas can also be provided.

According to one embodiment, the ratio x1: y1 or x2: y1 of the distance x1, x2 of the combustion air inlet and / or the mixed gas inlet to the opposite rotor wall is at least 90% and / or a maximum of 290%, in particular between 200% and 250%. In other words: the inlets remain comparatively far away from the center in the x direction, at least one of the inlets. This allows the gas distribution to be further differentiated.

According to one embodiment, the combustion air inlet is arranged further inside closer to the opposite rotor wall than the mixed gas inlet (or vice versa), in particular with a difference in distance of at least 10mm or at least 50mm, in particular in an at least approximately central area centrally between the opposite one Runner walls. Such an offset in the y-direction allows the flow paths to be fanned out further. According to one embodiment, the combustion air inlets and the mixed gas inlets of a twin heating flue are arranged relative to one another in such a way that a line connecting the inlets is a diagonal or extends at least approximately diagonally through the respective heating channel, in particular a straight diagonal through the center points of the inlets, in particular a diagonal at an angle in the range from 40 ° to 50 ° with respect to the horizontal x-direction, in particular a diagonal running through the corner points between the runner and truss wall. In this way, an advantageous local diversification of temperature and substance transport can be set in the respective heating flue. The diagonal configuration can also be characterized by an at least approximately aligned arrangement on a line between diagonally opposite corners.

The above-mentioned object is also achieved according to the invention by a coke oven device for producing coke by coking coal at least with mixed gas heating, with nitrogen oxide emissions minimized by internal thermal energy balance, with a large number of twin heating ducts with heating ducts in pairs, each of which is delimited from one another by a partition and through two opposing rotor walls are sealed off, with at least one inlet from the following group being provided at the bottom of the respective heating duct: coke oven gas inlet, combustion air inlet, mixed gas inlet; The paired heating channels are fluidically coupled to one another by means of at least one upper coupling passage and also by means of at least two lower coupling passages each for internal exhaust gas recirculation on at least one circular flow path, with the ratio of the distance between the facing edges of the combustion air inlet and the mixed gas at the respective bottom - The inlet to the distance between the inner edges of the partition walls is at least 10%, the distance between the facing edges of the combustion air inlet and the mixed gas inlet being at least 50mm, with at least one of the combustion air and mixed gas inlets being eccentrically larger at an x distance Factor 0.7 of the absolute x-extension of the heating channel between opposite ones Rotor walls is arranged; The paired heating channels are fluidically coupled to one another by means of at least two lower coupling passages, the combustion air inlet being arranged at least approximately in the same x-position as the corresponding lower coupling passage, in particular with the respective midpoint of the combustion air inlet and the corresponding passage in an arrangement on the same x-coordinate, in particular in combination with the features of a coke oven device described above. This provides the aforementioned advantages, in particular with regard to primary mixing of recirculation gas and combustion air before combustion.

The aforementioned object is also achieved according to the invention by a coke oven device for producing coke by coking coal at least with mixed gas heating and with nitrogen oxide emissions minimized by internal thermal energy balancing, with a large number of twin heating flues with heating ducts, each of which is separated from one another in pairs by a partition and by two opposing rotor walls are sealed off, the paired heating channels being fluidically coupled by means of at least one upper coupling passage and also by means of at least one lower coupling passage each for internal exhaust gas recirculation on at least one circular flow path, with at least one inlet in the lower area at the bottom of the respective heating channel the following group is provided: coke oven gas inlet, combustion air inlet, mixed gas inlet; where on the respective floor the ratio y1: y2 of the distance y1 between the facing edges of the combustion air inlet and the mixed gas inlet to the distance y2 of the inner edges of the partition walls is at least 10%, the distance y1 between the facing edges of the combustion air inlet and the mixed gas inlet is at least 50mm, with at least one of the combustion air and mixed gas inlets being arranged eccentrically at an x distance greater than a factor of 0.7 of the absolute x extension of the heating duct between opposite rotor walls; in particular the coke oven device described above; furthermore the distance y1 is at least 100mm, in particular at least 150mm, where the Combustion air inlet and the mixed gas inlet are arranged offset in the x direction with respect to the opposite rotor wall. This provides many of the aforementioned advantages.

The aforementioned object is also achieved according to the invention by a coke oven device for producing coke by coking coal or coal mixtures, at least with mixed gas heating and optionally also with occasional coke oven gas heating, the coke oven device being set up for minimized nitrogen oxide emissions through internal thermal energy compensation by means of the steel mill's own gases and coke oven's own gases a multitude of twin heating flues each with a heating duct flamed with gas and a heating duct flowing downwards through the exhaust gas, which heating ducts are separated from each other in pairs by a partition and sealed off from a respective furnace chamber by two opposing rotor walls, the paired heating ducts being fluidically coupled by means of at least one upper coupling Passage and also by means of at least one lower coupling passage each for internal exhaust gas recirculation on at least one circle Trompfad are coupled to each other, with at least one inlet from the following group being provided in the lower area at the bottom of the respective twin heating flue: coke oven gas inlet, combustion air inlet, mixed gas inlet, the lower coupling passage for internal exhaust gas recirculation being a coupling channel , which extends at least in sections through a central building area located below the paired heating channels and connects the heating channel, which is flamed with gas, to the heating channel through which the exhaust gas flows downwards. Advantageously, by means of the coupling channel, the recirculation gas is introduced essentially in a vertical direction into the gas-flamed heating channel. Rather, an essentially horizontal inflow direction of the recirculation gas into this gas is known from the general prior art. It is possible that the coupling channel extends below the twin heating flue in such a way that its inlet opening for admitting or receiving the recirculation exhaust gas is formed in the bottom area of the heating channel through which the exhaust gas flows, while its outlet opening for discharging the recirculation exhaust gas in the bottom area of the gas-flamed heating channel is trained. It is furthermore conceivable that at least the inlet opening is formed centrally between the central / coupling partition and the outer / partitioning partition lying opposite this central / coupling partition. It is also possible for the outlet opening to be formed centrally between the central / coupling partition and the outer / partitioning partition lying opposite this central / coupling partition. The central / coupling partition has at least one more passage opening or a coupling passage, in particular an upper coupling passage for recirculation of the recirculation gas and is arranged between the two heating channels of the twin heating flue. However, it is also possible that at least the outlet opening and / or the inlet opening is / are formed decentrally between the central / coupling partition and the outer / partitioning partition opposite this central / coupling partition, in particular closer to the central / coupling partition in the y-direction considered. Viewed in the x direction, it is possible for the inlet opening and / or the outlet opening to be / are formed centrally / centrally between the corresponding rotor walls. A decentralized design is also conceivable. It is also conceivable that the coupling channel has an inlet opening and / or an outlet opening, the size of which, in particular cross-sectional size, covers a quarter, in particular a third of the bottom area of the exhaust gas-carrying downward flow-through heating channel or of the heating channel flamed with gas. The coupling channel can be designed with a round, oval, angular, in particular rectangular or polygonal cross section.

The central building area is a block of refractory material that connects the individual combustion shafts or twin heating flues with the regenerators (air preheating) through ducts. Extend through this central building area For example, the gas ducts, in which fuel gas and air alternately lead from the regenerator up into the twin heating duct, in particular into the heating duct flamed with gas for combustion, as well as exhaust gas from the twin heating duct, in particular from the exhaust-gas conducting downward flow heating duct into the regenerator for evacuation downwards will.

The aforementioned object is also achieved according to the invention by a method for operating a coke oven device for producing coke by coking coal or coal mixtures with optimized minimized nitrogen oxide emissions through internal thermal energy compensation by means of gas from the steelworks (blast furnace original gases) and coke oven gases by measures taken internally on the coke oven device at least with mixed gas heating and optionally also with occasional coke oven gas heating, in particular for operating a coke oven device described above, with an internal exhaust gas recirculation on at least one circulating current path in a respective twin heating duct of the coke oven device with a flamed heating channel and an exhaust gas-carrying heating channel by means of at least one coupling passage through a partition the partition is set around, with at least two gases from the following group in the lower area at the bottom of the respective twin heating flue e: coke oven gas, combustion air, mixed gas, the group of admitted gases comprising at least the two gases combustion air and mixed gas; whereby the combustion air and the mixed gas are admitted on flow paths at a distance y1 to each other in the ratio y1: y2 of at least 10% to the distance y2 of the inner edges (inner surfaces) of the partition walls of the respective heating duct, whereby the distance y1 of these two flow paths is at least 50mm, with combustion air and / or mixed gas being let in eccentrically at an x distance greater than a factor of 0.7 of the absolute x extension of the heating channel between opposing rotor walls. This provides the aforementioned advantages. According to one embodiment, the cross-sectional area of the combustion air inlet and / or the mixed gas inlet are adjusted with regard to geometry and / or size on the respective floor, in particular by means of at least one slide valve. This enables further optimization.

According to one embodiment, the flame temperature with mixed gas heating is a maximum of 1,700 ° C or a maximum of 1,600 ° C or a maximum of 1,500 ° C, in particular with a nozzle stone temperature of at least 1,300 ° C or at least 1,320 ° C. This can also create an advantageous framework for operating parameters and output. In particular, the device can optionally be operated with regard to maximized output (no strict NOx limit values), or alternatively with regard to minimized NOx emissions. Compared to previously known devices, a higher output can be achieved with a comparatively high NOx emission.

According to one embodiment, the gas flows in the respective heating flue are set in such a way that the ratio of flame temperature to nozzle brick temperature is minimized, in particular at a nozzle brick temperature of at least 1,300 ° C or 1,320 ° C. Such a minimized ratio can in each case characterize a comparatively homogeneous temperature distribution, with as few or small areas as possible with temperature peaks. This also provides process optimization in terms of output and economy.

According to the invention, a bulge in the temperature profile can be homogenized over the height. Up to now, many constructions have usually had a two-stage temperature profile across the height, each with a comparatively pronounced "belly" or a comparatively blatant uneven distribution. The arrangement according to the invention enables the temperature profile to be flattened, in particular over a large height section of the entire heating flue.

According to one embodiment, the mixed gas and / or the combustion air is / are at least approximately in at the respective bottom by means of the respective inlet let in vertical direction. Alternatively, the mixed gas and / or the combustion air can be admitted in a direction inclined with respect to the vertical at the respective floor by means of the respective inlet. The mixed gas and / or the combustion air can optionally be admitted at the respective bottom with a vortex or with a swirl impulse on at least one spiral flow path. This also enables a fine adjustment of flow paths.

According to one embodiment, the admitted gas (in particular combustion air, mixed gas) and / or the circulating gas is aligned or guided in the horizontal direction, in particular at several height levels, in particular by means of baffles or baffle plates or stones or screens, in particular each made of refractory material. This enables further optimization measures with regard to internal energetic mixing and flattening of temperature profiles, especially over the height of the heating flue.

According to one embodiment, the gas (combustion air and / or mixed gas) is admitted by means of the inlets at different height levels, in particular with the mixed gas inlet at a height level above the combustion air inlet, in particular by means of the mixed gas inlet in an arrangement on a base above the Soil. This also enables further influence on the temperature distribution.

The above-mentioned object is also achieved according to the invention by a method for operating a coke oven device for producing coke by coking coal or coal mixtures with optimized minimized nitrogen oxide emissions through internal thermal energy compensation by means of steel mill's own gases and coke oven's own gases by measures internal to the coke oven device at least with mixed gas heating and optionally also with temporary coke oven gas heating, in particular for operating a coke oven device according to one of the preceding claims, wherein in a respective twin heating duct of the coke oven device with a flamed heating channel and an exhaust gas-carrying Internal flue gas recirculation on at least one circulating flow path around the partition is set in the heating channel by means of at least one coupling passage through a partition, with at least two gases from the following group being admitted in the lower area at the bottom (5.4) of the respective twin heating flue: Coke oven gas (G1 a ), Combustion air (G1), mixed gas (Gi b), the group of gases admitted comprising at least the two gases combustion air (G1) and mixed gas. In this case, a recirculation gas of the exhaust gas recirculation flows through a central building area located at least in sections below the paired heating channels and connecting the gas-flamed heating channel with the exhaust-carrying, downward-flowing heating channel in such a way that the recirculation gas is introduced essentially in a vertical direction into the gas-flamed heating channel becomes. Essentially means here that the recirculation gas flows or is admitted into the heating channel at least almost / approximately / approximately in the vertical direction (z-direction).

The aforementioned object is also achieved according to the invention by using combustion air and mixed gas inlets in a coke oven device with a large number of twin heating flues each with two heating channels for producing coke by coking coal or coal mixtures, at least with mixed gas heating and optionally also with occasional coke oven gas heating, in particular in a coke oven device described above, with an internal exhaust gas recirculation on at least one circular flow path being set in a respective twin heating flue by means of at least one coupling passage, the inlets to minimize nitrogen oxide emissions through internal thermal energy compensation in a ratio y1: y2 of the distance y1 between facing edges of the Combustion air inlet and the mixed gas inlet are arranged at the distance of the inner edges of the partition walls of a respective heating duct of at least 10%, the distance y1 between the facing th edges of the combustion air inlet and the mixed gas inlet is at least 50mm. This provides the aforementioned advantages. The above-mentioned object is also achieved according to the invention by using combustion air and mixed gas to minimize nitrogen oxide emissions through internal thermal energy compensation in heating channels of a plurality of twin heating flues of a coke oven device, in particular in a coke oven device described above, with one in a respective twin heating flue by means of at least one coupling passage internal exhaust gas recirculation is set on at least one circular flow path, the combustion air and the mixed gas in a distance ratio y1: y2 of the distance y1 between their inlets and the distance y2 of the inner edges of partition walls of a respective heating duct of at least 10% and at a distance from one another of at least 50mm be admitted, in particular at a flame temperature with mixed gas heating of a maximum of 1,700 ° C or a maximum of 1,600 ° C or a maximum of 1,500 ° C, in particular at a nozzle stone temperature of at least 1,300 ° C or at least 1,320 ° C. This provides the advantages mentioned above, in particular when the nozzle stone temperature is increased by at least 20 Kelvin compared to previous operating modes (optional) with the same or lower NOx emissions.

With the method described, all the advantages that have already been described for a coke oven device according to the first aspect of the invention result.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.

Further features and advantages of the invention emerge from the description of at least one exemplary embodiment on the basis of drawings, as well as from the drawings themselves. FIG 1A, 1 B, 1 C, 1 D, 1 E, 1 F, 1G, 1 H each in a schematic representation in sectional side views and plan views of twin heating ducts or coke ovens according to the prior art;

2A, 2B, 2C, 2D, 2E each in a schematic representation in sectional side views and in plan views of twin heating cables or coke oven devices according to exemplary embodiments;

3, 4, 5, 6, 7 each in a schematic representation in plan view a relative

Arrangement of inlets according to an embodiment;

Fig. 8 in a schematic representation in plan view of a relative arrangement of

State of the art inlets;

Fig. 9 in a schematic representation in plan view constructive sizes

Twin heating coils;

10A, 10B, 10C each in a schematic representation in plan view a relative

Arrangement of the inlets relative to a more distant lower recirculation passage according to an embodiment;

11 shows a schematic representation in plan view of a relative arrangement of the

Inlets relative to a single lower recirculation passage according to one embodiment;

Fig. 1 1 a in a schematic representation in plan view of a relative arrangement of the inlets relative to a single lower

Recirculation passage according to an embodiment;

Fig. 12 in a schematic representation in plan view an illustration of a

Flow exchange section with a relative arrangement of the inlets according to the prior art;

13A, 13B each in a schematic representation in plan view an illustration of a

Flow exchange section with a relative arrangement of the inlets according to one of the exemplary embodiments;

Figs. 14, 15, 16,

17, 18, 19 each in a schematic representation in sectional side views

Twin heating cables according to exemplary embodiments. In the case of reference symbols that are not explicitly described with reference to an individual figure, reference is made to the other figures. In figures describing the state of the art, the positions and angular orientations of the individual inlets and passages or flow paths are only exemplary (in particular only in individual heating channels) and are not fully illustrated or, if applicable, are not arranged precisely at an angle.

In figures which describe the present invention, the positions and angular orientations of the individual inlets and passages or flow paths are illustrated schematically (in particular only in individual heating channels), the amounts of the respective distances being defined in more detail in the description. It should be noted that different reference symbols were used for one and the same features in the figures relating to the prior art in comparison to the figures which show exemplary embodiments of the present invention. However, this does not affect the ability to combine the individual features with one another.

DETAILED DESCRIPTION OF THE FIGURES

Figures 1A, 1 B, 1 C, 1 D, 1 E, 1 F, 1 G, 1 H show a coke oven 1 in the manner of a horizontal chamber oven, with several oven chambers 2 each with a coal charge. The furnace chambers 2 have a height of e.g. 6 to 8m. The furnace chambers 2 are partitioned off by rotor walls 3, which each extend in a yz plane. Between two rotor walls 3, heating channels 5.1, 5.2 in pairs each form a twin heating duct 5, the inner wall 5.3 of which delimits the heating space through which gases flow (free of coal) from the respective furnace chamber. The heating channels 5.1, 5.2 are alternately operated as a flamed or exhaust-gas-carrying heating channel, which requires switching the direction of flow and in a cycle of e.g. 20 minutes.

The paired heating channels are each separated from one another by a coupling partition (binder wall) 4, in which a coupling passage 4.4 is provided above and below, via which a circulating flow 9 of recirculated exhaust gas can be realized. Adjacent twin heating ducts are completely sealed off from one another by a separating partition 4a without any passages.

In each of the partition walls 4, 4a there is a step air duct 4.1 which is coupled to the heating duct via at least one combustion step 4.2 or the corresponding inlet or outlet. The respective combustion stage 4.2 can be arranged in a characterizing height position. For example, two or three height positions are defined in which step air is admitted.

The respective walls are in particular made of stones which, according to their dimensions, each define a wall layer.

The x-direction denotes the width of the furnace 1, the y-direction denotes the depth (or the horizontal push-out direction in the case of a horizontal chamber kiln), and the z-direction denotes the vertical (vertical axis). The central longitudinal axis M of the respective heating channel runs through the center of the respective heating channel (not explicitly marked; approximately in the center of the respective circular flow-around partition, in particular in the center of a centrally arranged step air channel), which is arranged centrally in the x and y directions in relation to the inner surfaces / inner walls ). The term “centric” or “center” here relates to a center in the xy plane, and the term “centered” or “center” here relates to the height direction (z).

Several inlets are arranged in the so-called burner level 5.4 or at the bottom of a respective heating channel, namely a (first) combustion air inlet 6, in particular for coke oven gas heating, and a further combustion air inlet 7, in particular for mixed gas heating, and a coke oven gas inlet 8 Gas introduced via these inlets flows upwards on the wall surfaces 4.3 of the partition walls and on the inner walls of the rotor walls.

The following temperatures at the coke oven 1 that are characteristic for the furnace builder / operator can be mentioned: nozzle stone temperature T1, (gas) temperature T2 in the respective heating channel, Temperature T3 in the furnace chamber. The present invention relates in particular to a profile that is as homogeneous as possible with regard to temperature T2 (in particular also in the vertical direction).

The individual gas flows are described below with reference to FIGS. 1 F to 1 H. The gas flow G1 identifies newly admitted or supplied heating gas or combustion air. The gas flow G1 can comprise a gas flow G1 a (coke oven gas) and / or a gas flow Gi b (mixed gas). The gas flow G4 identifies recirculation exhaust gases that are returned or circulated. The gas flow G5 identifies gas or air from a respective combustion stage 4.2, 14.1 1, and the gas flow G6 identifies exhaust gases that are discharged from the respective heating duct or heating flue.

The recirculation arrows shown in FIG. 1D are only shown schematically and do not exactly reflect the direction of the respective gas flow.

Fig. 1G shows schematically a heating differential 5.6 with individual openings 5.61 through which the gas can be diverted in a head area of the heating channel. The heating differential 5.6 is sealed off from the respective twin heating flues by an (intermediate) ceiling 5.7. The heating differential 5.6 is independent of the circulating current 9. A distance E between the heating differential 5.6 and the passage 4.4 can be designed individually for each furnace. The reference symbol E can also characterize a cross-sectional area. The cross-sectional area E is preferably at least 300 cm ² or at least 340 cm ² .

An illustration of the central structure of the furnace located below the burner level 5.4 is deliberately omitted for the sake of better clarity. The supply of gases and the regulation of the volume flows can take place in the central building.

Figures 2A, 2B, 2C, 2D, 2E show a coke oven device 10 according to an embodiment, comprising: oven chamber 10.2, flamed heating channels 1 1, Inner wall 11.1, exhaust gas-carrying heating ducts 12, twin heating ducts 13, partition walls 14 with inner surface 14.3, partitioning walls 14a without passages, step air ducts 14.1 with combustion stages 14.11, coupling passages 14.2, bulges 14.4, runner walls 15 with inner surface 15.1, combustion air inlets 16, mixed gas inlets 17 , Coke oven gas inlets 18, slide blocks 19.

With reference to FIGS. 2A, 2B, 2C, 2D, 2E, the distances according to the invention and relative positions of the individual inlets and passages are described below using further exemplary embodiments.

In FIG. 2A, the paired arrangement of the inlets 16, 17 opposite to the inlet 18 is schematically (in some heating channels).

In FIG. 2B it is shown that the inlets 16, 17 are offset comparatively strongly outwards in the x-direction (eccentrically), and are at a comparatively great distance from one another in the y-direction. The arrangement of the optional coke oven gas inlet 18 is independent of this, or can be chosen largely freely.

In FIG. 2C it is shown that an advantageous relative arrangement with respect to the step clearance G4 can also be realized through the offset in the x and y directions. The angle indicated in FIG. 2C for an angular alignment of the inlets can be varied individually for each inlet. Depending on the design of the central structure, e.g. an angle in the range of 5 to 10 ° could be a rational compromise of additional constructional, technical system effort and achievable thermal and / or fluidic effects.

The passages 14.2 or the step gas inlet 14.11 shown in FIG. 2C can also be varied in their arrangement, number and geometry according to the variants shown or discussed in the other figures. The individual gas flows are described below with reference to FIGS. 2C and 2E. The respective gas flow path GP1 characterizes inflow paths or flow paths according to the invention for at least one of the gases G1 introduced via the inlets. The respective gas flow path GP4 identifies flow paths of recirculated exhaust gas / flue gas G4, and the respective gas flow path GP5 identifies flow paths of gas G5 introduced in stages.

2D particularly illustrates the comparatively large distance y1.

FIG. 2E shows a view analogous to that according to FIG. 2C. The inflow angle illustrated in FIGS. 2C, 2E, in particular for coke oven gas, is preferably less than 30 °, in particular less than 10 °, in each case with respect to the z-axis. The inflow angle can also be implemented for the further inlets 17, 18 in a similar manner.

The distances and relative positions mentioned in relation to the respective inlets and passages can also reciprocally refer to the distances and relative positions of the respective gas flow paths / circulating flow paths, at least in a section upstream of a subsequent mixing with adjacent gas flows.

3 shows an arrangement with the inlets 16, 17 on the same x-coordinate (x1 = x2) at a comparatively large distance from the opposite runner wall 15. The ratio y1: y2 is in the range from 25% to 30%, so it is comparative large. Y1 is greater than 50mm. With this arrangement in particular, the advantage of flexible compensation for pressure losses can also be ensured.

Fig. 3 shows in particular an advantageously adjustable inlet cross-section of both openings (gas and air). In addition to optimizing internal energy distribution, this also enables process engineering variations, particularly in connection with the following situations:

- comparatively high pressure loss (eg in summer) in the heating flue: slide valve opened to minimize pressure loss; - Regulation of pressure loss and flow rates, in particular to adapt the performance capacity of the plant (in particular depending on the desired coke output);

- Regulation of pressure loss and flow rates, in particular to adapt the operating parameters to the input material (adaptation of the so-called coal base), e.g. higher gas demand with increasing water content;

In all the exemplary embodiments shown, inner corners between the walls can also have radii or be rounded, in particular for reasons of stability, in particular in the form of so-called head ties. The proportions and dimensions according to the invention are independent of such roundings; rather, the proportions and dimensions relate to the distances from parallel walls or from at least approximately parallel wall sections, in particular to the respective largest distances in the relevant cross-sectional plane.

3 shows an arrangement in which the air inlet 16 and mixed gas inlet 17 completely overlap in the x direction, the inlets being arranged without an x offset and having at least approximately the same x extension.

4 shows an arrangement with the inlets 16, 17 on different x coordinates (x1> x2) at a comparatively large distance y1. The ratio y1: y2 is in the range from 25% to 30%. Y1 is much larger than 50mm. The extension y2 is dimensioned as such (per se) in relation to the inner surface of the respective partition wall, in particular in relation to the most distant parallel section of the partition wall, i.e. independent of any optionally provided bulges 14.4 for step air ducts. Such bulges 14.4 are optionally provided, in particular for reasons of stability, in the case of comparatively narrow partition walls. The y dimension (depth) is, for example, in the range from 5 to 40mm. Especially in the case of an arrangement according to FIG. 4, the advantage of great flexibility with regard to varying operating parameters can also be ensured. 4 also shows, in particular, measures with regard to the size and geometry of the outlet openings. In addition to optimizing internal energy distribution, this also enables process engineering variations, particularly in connection with the following situations:

- Parameter optimization, particularly with regard to changes in gas quality: in the course of the service life, a low-calorific mixed gas (especially with lower calorific values less than 4185 kJ per Nm ³ ; typical lower calorific values of mixed gases in the range from 4185 to 5500 kJ per Nm ³ ) can be used;

- Variation of the gas / air ratio on the ground over a comparatively large area with a good effect on the vertical temperature distribution; this can be advantageous in particular if a change in the capacity of the furnace becomes necessary or if the heating system or the coal base is changed.

4 shows an arrangement in which the air inlet 16 completely overlaps the mixed gas inlet 17 in the x direction.

5 shows an arrangement with the inlets 16, 17 on comparatively clearly / strongly different x coordinates (x1> x2) at a comparatively large distance y1, with the inlets 18 each being arranged comparatively far in the middle in the x direction, in particular also at least approximately in the middle in the y-direction. The ratio y1: y2 is in the range from 25% to 30%. Y1 is greater than 50mm. The ratio x2: x1 is e.g. in the range of 0.7. With this arrangement in particular, the advantage of high practicality with regard to parameter variations can also be ensured.

In particular, FIG. 5 also shows measures with regard to the geometry of the inlets or with regard to their design as nozzles. In addition to optimizing internal energy distribution, this also enables process engineering variations, particularly in connection with the following situations: - Air opening on the floor in the form of a nozzle 16 (illustrated by round cross-sectional geometry); Nozzles can be more easily accessible and replaceable than slide blocks, especially when they are accessed from above from the ceiling.

5 shows an arrangement in which the air inlet 16 completely overlaps the mixed gas inlet 17 in the x direction.

In all of the exemplary embodiments shown, the coke oven gas inlets can optionally also be integrated into the partition, that is to say not arranged at a distance from the partition in the y-direction, but rather built into the partition.

6 shows an arrangement with the inlets 16, 17 on comparatively clearly / strongly different x coordinates (x1 <x2) at a more or less maximum distance y1. The ratio y1: y2 is in the range from 25% to 30%. Y1 is much larger than 50mm. The ratio x1: x2 is e.g. in the range of 0.7. In embodiments according to FIG. 6, particularly advantageous effects with regard to NOx reduction and also with regard to further operating parameters such as e.g. Pressure loss can be ensured.

In the exemplary embodiments according to FIG. 6, the air and mixed gas inlets 16, 17 can in particular be arranged without any overlap in the x direction.

FIG. 7 shows an arrangement comparable to that according to FIG. 6, the offset between the inlets 16 and 17 being inverted (x1> x2). The ratio y1: y2 is in the range from 25% to 30%. Y1 is much larger than 50mm. The ratio x2: x1 is e.g. in the range of 0.6 or 0.5. With this arrangement in particular, the advantage of a very effective mixing of recirculated exhaust gas with air can be ensured.

In embodiments according to FIG. 7, thanks in particular to the arrangement of the air inlet 16 in the area of the recirculation openings 14.2 (in particular comparable x-coordinate) influence on the gas composition before its combustion. In particular, the recirculated exhaust gas is mixed with the air shortly after the respective recirculation opening, in particular without a combustion already being caused there. This procedural arrangement can also be described as primary mixing of flue gas and air. Effect: Thanks to the arrangement according to the invention, external recirculation of flue gas and air is not necessary; as a result, measures with regard to larger flow cross-sections in the regenerator can also be saved.

In the exemplary embodiments according to FIG. 7, the air and mixed gas inlets 16, 17 can in particular be arranged without any overlap in the x direction, in particular asymmetrically to the arrangement shown in FIG. 6.

In the exemplary embodiments according to FIGS. 6, 7, in particular slide blocks can also be provided.

8 shows an arrangement according to the prior art, with the inlets 6, 7 on a comparable (in particular identical) x-coordinate and offset comparatively strongly towards the x-center, in particular in an at least approximately central x-arrangement, the inlet 8 is arranged on an x-coordinate in the area of recirculation openings. The distance y1 is on average large, and the ratio y1: y2 is on average large. The x-coordinate of the inlets 6, 7, in particular of their centers, is approximately half the absolute x-width of the respective heating flue, and lies in particular within the following range for the ratio of the absolute x-distance of the runner walls 15 to x1 or to x2: range from 0.4 to 0.6.

FIG. 9 describes an exemplary arrangement of the openings according to the invention in the context of further structural details of a furnace. The furnace pitch xO is in particular in the range from 1000 to 1800 mm (dimension from furnace chamber half to furnace chamber half; center to center). The heating duct division yO is in particular in the range from 400 to 550 mm (center partition to center partition). The partition walls 14 have eg a thickness (y-dimension) in the range from 130 to 170mm. The rotor walls 15 have, for example, a thickness (x dimension) in the range from 70 to 130 mm.

The y-extension of the combustion air inlets 16 is, for example, in the range greater than or equal to 50 mm, with a minimum distance from the closest partition 14 of at least 50 mm. The y-extension of the mixed gas inlets 17 is, for example, in the range greater than or equal to 50 mm, with a minimum distance from the closest partition 14 of at least 50 mm. The x-extent of the combustion air inlets 16 is, for example, in the range greater than or equal to 100 mm, with a minimum distance from the rotor wall 15 of at least 50 mm. The x-extension of the mixed gas inlets 17 is, for example, in the range greater than or equal to 100 mm.

FIGS. 10A, 10B, 10C illustrate in particular the “forward burning” operating mode, with recirculation passages being provided in pairs by way of example. 10A describes an exemplary arrangement according to the invention with the inlets 16, 17, 18 in such a relative arrangement to the more distant lower recirculation passage 14.2 (in each case center points) that a square with an area A is spanned. The surface area is, for example, in the range from 500 cm ² to 1,700 cm ² , in particular in the range from 1,000 cm ² to 1,500 cm ² . 10A further illustrates the exit plane xz14 of the partition wall 14. The relevant corner point of the polygon, on the other hand, is offset inwards to the center of the wall. The area information is therefore independent of the wall thickness of the partition 14.

10B describes an exemplary arrangement according to the invention with the inlets 16, 17, 18 in such an arrangement relative to the more distant lower one

Recirculation passage 14.2 (each center point) that a square with a

Area A is spanned. The surface area is in particular in the range from 700 cm ² to 1,600 cm ² . The basic shape of the square is trapezoidal.

10C describes an exemplary arrangement according to the invention with the inlets 16, 17, 18 in such a relative arrangement to the more distant lower one Recirculation passage 14.2 (center points in each case) that a square with an area A is spanned. The surface area is in particular in the range from 500 cm ² to 1,400 cm ² .

It has been shown that for the “forward-burning” furnace configurations described above, an area A in the range from 1,100 to 1,500 cm ^{2 can be} particularly advantageous. Depending on the individual design of the furnace (size, output), an advantageous range of 200 cm ² to 2,000 cm ² can be defined for the area A, particularly preferably 500 cm ² to 1,500 cm ² , especially in the case of comparatively large ovens with an oven chamber fleas of more than seven (7) meters, more preferably 700cm ² to 1,500cm ² , that is to say for the fleas of more than 7 meters that have become common in many applications in recent years.

FIG. 11 describes an exemplary arrangement according to the invention with reference to an oven design with only one lower recirculation passage, in particular with so-called “back-to-back” heating. The inlets 16, 17, 18 are so arranged relative to one another and relative to the (single) lower recirculation passage 14.2 (in each case center points) that a square with an area A is spanned. The area is for example in the range of 300 cm ² to 1300 cm ^2, in particular in the range from 800cm ² to 1 .300cm ²

It has been shown that with this “back-to-back” configuration, an area A in the range from 1,000 to 1,250 cm ^{2 can be} particularly advantageous. Depending on the individual design of the furnace (size, output), an advantageous range of 50 cm ² to 1,800 cm ² can be defined for the area A, particularly preferably 300 cm ² to 1,300 cm ² , especially in the case of comparatively large furnaces with a furnace chamber flea of more than 7 meters, more preferably 500 cm ² to 1,300 cm ² .

In the arrangements shown in FIGS. 10A to 10C and 11, a triangle can optionally also be spanned, namely in the event that the high-gas inlet 18 is on a connecting line from one of the further inlets 16, 17 to the center point of the recirculation passage 14.2 (cf. in particular FIG. 1 1), or in the event that the inlet 16 is arranged on a connecting line between the inlet 17 and the recirculation passage 14.2. In particular, an inclined, in particular uneven arrangement of the inlets 16 and 17 with regard to a straight line G extending between the partition walls 14 and running parallel to the rotor wall 15 is shown in FIG. In contrast to the embodiment of FIG. 11, the inlets 16, 17 according to FIG. 11a are no longer parallel to one another, in particular with their midpoints lying on the above-mentioned straight line G. This means that the inlet 17, in particular its center point, is arranged (formed) on the above-mentioned straight line G, while the inlet 16, in particular its center point in the direction of the recirculation passage 14.2, is formed offset from the straight line G or vice versa.

In the arrangements shown in FIGS. 10A to 10C and 11, the geometric centers of the inlets of the respective heating flue and of the at least one lower coupling passage, in particular one of several lower coupling passages that are further away from the combustion air and mixed gas inlet, define a square arrangement Area in plan view is at least 50 cm ² , preferably at least 200 cm ² or at least 300 cm ² or at least 500 cm ² or at least 700 cm ² .

In the arrangements described above, the height positions of the inlets can vary downwards or upwards with respect to the burner plane, as generally described above.

12 describes a relative arrangement of the mixed gas inlet 17 relative to the combustion air inlet 16 according to the prior art. A flow exchange section B resulting between these two adjacent inlets 16, 17, in the sense of a fluidically acting contact surface between two different types of gas or gas mixtures, is arranged orthogonally to cross connections between these inlets. It has been shown that this arrangement works with A comparatively small y-distance and a comparatively large flow exchange area leads to strong mixing just above the inlets, with the effect that a high temperature (excessively high maximum temperature) occurs and a disadvantageously high NOx emission cannot be avoided or only avoided by countermeasures can.

13A shows a relative arrangement of the mixed gas inlet 17 relative to the combustion air inlet 16 according to one of the measures according to the present invention. The flow exchange section B is comparable in size as in the arrangement according to FIG. 12. The inlets overlap completely and are designed to be the same size, at least in the x direction. However, the distance in the y direction is significantly greater than in the arrangement according to FIG. 12, with the effect that the mixing of air and mixed gas (in terms of time or in relation to the direction of fleas) can be delayed and / or less thorough mixing he follows. With this arrangement, the comparatively large flow exchange area is not a disadvantage.

13B shows an arrangement in which the flow exchange area or the flow exchange section B is reduced due to the lateral x-offset. As an example, the flow exchange section B is also plotted here orthogonally to cross connections between the inlets. The inlets overlap only very slightly or, optionally, not at all. The y-distance is comparably large to that according to the arrangement in FIG. 13A. It has been shown that with this combined measure the mixing of air and mixed gas can be significantly delayed, and that a very advantageous temperature distribution, in particular over the fleas of the meat course and optionally also in other dimensions of the meat course, can be ensured. The NOx emissions can be reduced very effectively.

FIGS. 14, 15, 16, 17, 18 and 19 each show exemplary embodiments of a twin heating flue 13 of a coke oven device according to the invention. A heating differential 5.6 with individual openings is also shown schematically in FIGS. 14 and 15 5.61, through which the gas can be diverted in a head area of the heating duct. The heating differential 5.6 is sealed off from the respective twin heating duct 13 by an (intermediate) ceiling 5.7. The heating differential 5.6 is independent of the circulating current 9. For the sake of clarity, only a central building or a central building area 30 and an adjoining regenerator area 40 are shown schematically in FIG. However, these areas can also be transferred to the exemplary embodiments in FIGS. 15, 16, 17, 18 and 19. The central building area 30 is formed at least in sections below the burner level 5.4, in particular below the floor or floor area 5.4 of the twin heating flue 13 or the corresponding channels. In the central building area 30, the supply of gases and the regulation of the volume flows take place. The coupling channel 20 extends at least in sections within the central building area 30 and has an inlet opening 21 and an outlet opening 22. The inlet opening 21 is formed in the bottom area 5.4 of the exhaust gas carrying downward flow through heating channel 12 in order to transfer recirculation exhaust gas G4 from the exhaust gas carrying downward flow through heating channel 12 through the coupling channel 20 and via the outlet opening 22 into the gas flamed heating channel 1 1. The recirculation exhaust gas G4 is advantageously introduced in the vertical direction into the gas-flamed heating duct 11 and does not first have to be deflected from the essentially horizontal direction into a vertical direction, as in the prior art (see FIG. 1G).

As shown in the exemplary embodiment in FIG. 14 or in the exemplary embodiment in FIG. 18 or in the exemplary embodiment in FIG. 19, the twin heating duct 13 only has an upper coupling passage. 14.2, which extends through the coupling partition 14. A lower coupling passage 14.2, which is required to enable recirculation of the recirculation gas G4, is formed by the coupling channel 20. This means that the coupling partition 14 is designed in such a way that it contacts the base 5.4 of the twin heating flue 13, so that no coupling passage 14.2 is formed between this base 5.4 and the coupling partition 14. The coupling partition 14 also has no further openings or passages which serve as a coupling passage 14.2, so that only a single circulating flow 9 is used to recirculate the recirculation exhaust gas G4. In addition to the above already adequately described gas inlets G1 and G1 a and gas outlets G6 in the bottom area 5.4 of the respective heating channels 1 1, 12 there is also at least one gas inlet for stage air gas G5, or, as shown in Figure 19, at least two gas inlets for stage gas G5 and at least an additional gas outlet for exhaust gas G6 is formed in the areas of the partitioning walls 14a, or as shown in FIG. 18 in the area of the coupling partition 14.

In contrast to the exemplary embodiment in FIG. 14, the exemplary embodiment in FIG. 15 has more than just one coupling passage 14.2, but three coupling passages 14.2 formed in the area of the coupling partition 14, which in addition to the coupling channel 20, which can be understood as the lowest coupling passage , are trained. With their help, the recirculation gas G4 can be recirculated or recirculated within the twin heating flue 13 in two circular flows 9, namely an inner circular flow and an outer circular flow.

In contrast to the exemplary embodiments in FIGS. 14 and 15, the exemplary embodiments in FIGS. 16 and 17 do not have a heating differential. According to the exemplary embodiment in FIG. 16, three coupling passages 14.2 are formed, one of these coupling passages 14.2 being formed by the coupling channel 20, which again represents the lowermost coupling passage 14.2. There is consequently an upper coupling passage 14.2 between the coupling partition 14 and the ceiling 5.8 of the twin heating flue 13 and a lower coupling passage 14.2 between the coupling partition 14 and a floor 5.4 of the twin heating flue 13. An additional gas outlet for discharging an exhaust gas G6 is provided in the coupling partition 14.

The exemplary embodiment shown in FIG. 17 is essentially similar to the exemplary embodiment shown in FIG. 15 with regard to the number and arrangement of the Coupling passages 14.2 or the coupling channel 20. However, FIG. 17 shows a large number of, in particular two, step air channels or step air channel outlets 4.2 arranged one above the other in the vertical direction (z-direction), which bring step air G5 into the gas-flamed heating channel 11 . It is also conceivable to design more than two step air ducts. In addition, an additional outlet for exhaust gas G6 is formed in a partitioning wall 14a of the exhaust gas-carrying heating channel 12.

List of reference symbols:

1 coke oven, especially a horizontal chamber oven

2 furnace chamber with charcoal charge

3 runner wall

4 coupling partition or truss wall

4a partitioning wall without openings

4.1 Duct or step air duct in partition

4.2 Combustion stage or inlet or outlet on the step air duct from / to the heating duct

4.3 Wall surface

4.4 Passage coupling two heating channels

(or flue gas reversal point or reversal point for heating gas)

5 twin heating ducts (arrangement of two vertical heating ducts in pairs)

5.1 Flamed heating duct (vertical heating duct)

5.2 Flue gas-carrying heating duct (vertical heating duct)

5.3 Inner wall

5.4 Burner level or floor of a heating duct / floor area

5.6 heating differential

5.61 single opening in the heating differential

5.7 (intermediate) ceiling of a heating duct

5.8 ceiling

6 (first) combustion air inlet, especially for coke oven gas heating

7 further combustion air inlet or inlet for mixed gas heating

8 Coke oven gas inlet or coke oven gas nozzle

9 circulating current

10 coke oven device, in particular with a horizontal chamber oven

10.2 Oven Chamber

11 flamed heating duct (vertical heating duct)

11.1 inner wall 12 exhaust gas-carrying heating duct (vertical heating duct)

13 twin heating flues (arrangement of two vertical heating flues in pairs)

14 Partition or truss wall

14a partitioning wall without openings

14.1 Duct or step air duct in partition wall

14.11 Combustion stage or stage air inlet or outlet on the stage duct from / to the heating duct

14.2 Passage coupling two heating channels

14.3 Inner surface of the partition

14.4 Bulge for step air duct

15 runner wall

15.1 Inner surface of the runner wall

16 (first) combustion air inlet or air inlet,

especially for coke oven gas heating

17 further combustion air inlet or mixed gas inlet,

especially for mixed gas heating

18 Coke oven gas inlet or coke oven gas nozzle

19 valve block

20 coupling channel

21 inlet opening

22 exhaust port

30 middle section

40 regenerator area

A area polygonal arrangement (triangle or square)

B flow exchange section

E Distance between the heating differential and the passage

G1 heating gas or combustion air

G1a coke oven gas Gi b mixed gas

G4 recirculation exhaust

G5 stage gas or stage air from combustion stage

G6 exhaust

GP1 Inflow path or flow path for at least one of the gases introduced via the inlets

GP4 flow path of recirculated exhaust gas / flue gas

GP5 Flow path of gas introduced in stages

M central longitudinal axis of the respective heating duct

T 1 nozzle stone temperature

T2 (gas) temperature in the heating flue / heating duct

T3 temperature in the furnace chamber x horizontal direction (width or length; longitudinal extension of the truss wall) xO furnace pitch

x1 Distance between the combustion air inlet and the opposite wall of the rotor x2 Distance between the mixed gas inlet and the opposite wall of the rotor xz14 Exit level, partition wall

y Depth or horizontal push-out direction (longitudinal extension of the runner wall) yO Heating duct division

y1 Distance between the facing edges of the combustion air inlet and the mixed gas inlet

y2 Distance between the inner edges of the partition walls

z vertical direction (vertical axis)

Claims

Patent claims:

1. Coke oven device (10) for producing coke by coking coal or coal mixtures, at least with mixed gas heating and optionally also with occasional coke oven gas heating, the coke oven device being set up for minimized nitrogen oxide emissions through internal thermal energy compensation by means of the steel mill's own gases (G1, G4, G5 ), with a large number of twin heating flues (13) each with a heating channel (11) flamed with gas and a heating channel (12) through which exhaust gas flows, which heating channels are separated from one another in pairs by a partition (14) and by two opposing rotor walls (15 ) are sealed off by a respective furnace chamber (10.2), the paired heating channels fluidically by means of at least one upper coupling passage (14.2) and also by means of at least one lower coupling passage

Passage for internal exhaust gas recirculation on at least one

Circular current path are coupled to one another, with at least one inlet from the following group being provided in the lower area on the bottom (5.4) of the respective twin heating flue: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17);

characterized in that at the respective bottom (5.4) the ratio (y1: y2) of the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) to the distance (y2) of the inner edges of the partition walls ( 14) of a respective heating duct (11, 12) is at least 10%, the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) being at least 50mm, with at least one of the combustion air - and mixed gas inlets (16, 17) is arranged eccentrically at an x distance greater than a factor of 0.7 of the absolute x extension of the heating channel between opposing rotor walls (15).

2. Coke oven device according to the preceding claim, wherein the distance (y1) is at least 100mm; and / or where the ratio (y1: y2) is at least 25%.

3. Coke oven device according to one of the preceding claims, wherein the geometric centers of the inlets of the respective heating flue and of the at least one lower coupling passage, in particular one of several lower coupling passages that are further away from the combustion air and mixed gas inlet, define a triangular or square arrangement, the Surface area (A) in plan view is at least 50 cm ² , in particular at least 200 cm ² or at least 300 cm ² or at least 500 cm ² or at least 700 cm ² or at least 900 cm ² , in particular between 1,000 cm ² and 1,350 cm ² ; and / or wherein the triangular or square arrangement has an area (A) in plan view of a maximum of 2,000 cm ² , in particular a maximum of 1,800 cm ² or a maximum of 1,500 cm ² or a maximum of 1,300 cm ² or a maximum of 700 cm ² , in particular between 1,000 cm ² and 1,300 cm ² .

4. coke oven device according to one of the preceding claims, wherein on

respective bottom of the cross-sectional area of at least 30cm amount of the combustion air inlet (16) and / or the mixed gas inlet (17) ^2, or at least 50 cm ^2; and / or wherein the cross-sectional area of the

Combustion air inlet (16) and / or the mixed gas inlet (17) amount to a maximum of 500 cm ² or a maximum of 400 cm ² ; and / or where the

Cross-sectional geometry of the combustion air inlet (16) and / or the mixed gas inlet (17) is rectangular or elliptical or round.

5. Coke oven device according to one of the preceding claims, wherein on

respective bottom the cross-sectional area of the combustion air inlet (16) and / or the mixed gas inlet (17) is designed to be adjustable in terms of geometry and / or size, in particular by means of at least one displaceable valve block and / or by means of at least one replaceable /

removable nozzle.

6. Coke oven device according to one of the preceding claims, wherein the at least one upper recirculation passage (14.2) coupling the two respective heating channels of a respective twin heating duct in the upper region is set up for the mutual transfer of gases, the Recirculation passage (14.2) has a cross-sectional area of at least 250 cm ² , in particular of a maximum of 1200 cm ² or a maximum of 1000 cm ² ; and / or wherein the paired heating channels are fluidically coupled to one another by means of at least two lower coupling passages, the combustion air inlet (16) being arranged at least approximately in the same x-position as the corresponding lower coupling passage, in particular with the respective center point of the combustion air inlet Inlet and the corresponding passage in an arrangement on the same x-coordinate; and / or wherein at least two lower coupling passages are provided, in particular in a paired arrangement at the same height position.

7. coke oven device according to any one of the preceding claims, wherein the

Combustion air inlet (16) and the mixed gas inlet (17) are arranged offset in the x direction with respect to the opposite rotor wall (15); and / or the edges of the combustion air inlet (16) and the mixed gas inlet (17) facing the rotor walls (15) at a different distance (x1, x2) from at least one of the two opposite rotor walls (15) of the respective twin heating cables are arranged, in particular with a distance difference of at least 10mm or at least 50mm; and / or where the ratio (x1: y1) or (x2: y1) of the distance (x1, x2) of the combustion air inlet (16) and / or the

Mixed gas inlet (17) to the opposite runner wall (15) is at least 90% and / or at most 290%, in particular between 200% and 250%, at a distance (y1).

8. coke oven device according to any one of the preceding claims, wherein the

Combustion air inlet (16) further inside closer to the opposite one

The rotor wall (15) is arranged towards the mixed gas inlet (17), or vice versa, in particular with a distance difference of at least 10mm or at least 50mm, in particular in an at least approximately central area centrally between the opposing rotor walls (15).

9. Coke oven device (10) for producing coke by coking coal at least with mixed gas heating, with internal thermal

Energy balance minimized nitrogen oxide emissions, with a variety of

Twin heating ducts (13) with heating ducts in pairs, each of which is separated from one another in pairs by a partition (14) and sealed off by two opposing rotor walls (15), with at least one inlet from the following group being provided at the bottom (5.4) of the respective heating duct: Coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17); wherein the paired heating channels fluidically by means of at least one upper coupling passage and also by means of at least two lower coupling passages each for internal

Exhaust gas recirculation are coupled to one another on at least one circular flow path, the ratio (y1: y2) of the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) to the distance ( y2) of the inner edges of the partition walls (14) is at least 10%, the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) being at least 50mm, at least one of the combustion air and Mixed gas inlets (16, 17) eccentrically at an x distance greater than a factor of 0.7 of the absolute x extension of the heating channel between opposite ones

Rotor walls (15) is arranged, and the paired heating channels are fluidically coupled to one another by means of at least two lower coupling passages, the combustion air inlet (16) being arranged at least approximately in the same x-position as the corresponding lower coupling passage, in particular with the respective center of the

Combustion air inlet and the corresponding passage in an arrangement on the same x-coordinate; in particular coke oven device (10) according to one of the preceding claims.

10. Coke oven device (10) for producing coke by coking coal at least with mixed gas heating and with internal thermal

Energy balance minimized nitrogen oxide emissions, with a variety of

Twin heating cables (13) with heating channels, which are each paired by a Partition wall (14) separated from each other and by two each other

opposing rotor walls (15) are sealed off, the paired heating channels being fluidically coupled to one another by means of at least one upper coupling passage and also by means of at least one lower coupling passage each for internal exhaust gas recirculation on at least one circular flow path, with the lower area on the bottom (5.4) of the respective Heating channel at least one inlet from the following group is provided: coke oven gas inlet (18), combustion air inlet (16),

Mixed gas inlet (17); wherein at the respective bottom (5.4) the ratio (y1: y2) of the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) to the distance (y2) of the

Inner edges of the partition walls (14) is at least 10%, the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) being at least 50 mm, with at least one of the combustion air and mixed gas inlets (16, 17) is arranged eccentrically at an x distance greater than a factor of 0.7 of the absolute x extension of the heating channel between opposing rotor walls (15); especially

Coke oven device (10) according to one of the preceding claims; wherein the distance (y1) is at least 100mm, in particular at least 150mm, the combustion air inlet (16) and the mixed gas inlet (17) being arranged offset in the x direction with respect to the opposite rotor wall (15).

11. Coke oven device (10) for producing coke by coking coal or coal mixtures, at least with mixed gas heating and optionally also with occasional coke oven gas heating, the coke oven device being set up for minimized nitrogen oxide emissions through internal thermal energy compensation by means of the steelworks own gases and coke oven own gases (G1, G4, G5 ), with a large number of twin heating flues (13) each with a heating channel (11) flamed with gas and a heating channel (12) through which exhaust gas flows, which heating channels are separated from one another in pairs by a partition (14) and by two opposing rotor walls (15 ) are sealed off by a respective furnace chamber (10.2), the pairs Heating ducts fluidically by means of at least one upper coupling passage (14.2) and also by means of at least one lower coupling passage, each for internal exhaust gas recirculation on at least one

characterized in that the lower coupling passage for the internal exhaust gas recirculation is a coupling channel (20) which extends at least in sections through a middle section (30) located below the paired heating channels and the heating channel (11) flamed with gas with the exhaust gas leading downwards flowed through heating channel (12) connects.

12. A method for operating a coke oven device (10) for producing coke by coking coal or coal mixtures with optimized minimized nitrogen oxide emissions through internal thermal energy compensation by means of the steel mill's own gases and coke oven's own gases (G1, G4, G5)

Measures internal to the coke oven device at least with mixed gas heating and optionally also with temporary coke oven gas heating, in particular for operating a coke oven device according to one of the preceding

Claims, wherein in a respective twin heating train (13) the

Coke oven device with a flamed heating channel (11) and a

exhaust gas-carrying heating channel (12) by means of at least one coupling passage (14.2) through a partition (14) an internal exhaust gas recirculation is set on at least one circular flow path around the partition, with at least two gases from the lower area at the bottom (5.4) of the respective twin heating flue the following group can be admitted: coke oven gas (G1a),

Combustion air (G1), mixed gas (Gi b), the group of gases admitted comprising at least the two gases combustion air (G1) and mixed gas (Gi b);

characterized in that on the respective bottom (5.4) the combustion air and the mixed gas on flow paths at a distance (y1) to each other in the ratio (y1: y2) of at least 10% to the distance (y2) of the inner edges (inner surfaces) of the partition walls (14) of a respective heating channel (11, 12), the distance (y1) of these two embedded flow paths at least 50mm is, with combustion air and / or mixed gas being admitted eccentrically at an x-distance greater than a factor of 0.7 of the absolute x-extent of the heating channel between opposing rotor walls (15).

13. The method according to the preceding method claim, wherein the cross-sectional area of the combustion air inlet (16) and / or the mixed gas inlet (17) are adjusted in terms of geometry and / or size, in particular by means of at least one slide block.

14. The method according to any one of the preceding method claims, wherein the

Flame temperature with mixed gas heating is a maximum of 1,700 ° C or a maximum of 1,600 ° C or a maximum of 1,500 ° C, especially with a

Nozzle stone temperature of at least 1,300 ° C or at least 1,320 ° C;

and / or wherein the gas flows in the respective heating flue are set in such a way that the ratio of flame temperature to nozzle brick temperature is minimized, in particular at a nozzle brick temperature of at least 1,300 ° C or 1,320 ° C.

15. The method according to any one of the preceding method claims, wherein the

admitted gas and / or the circulating gas is aligned or guided in the horizontal direction, in particular at several height levels, in particular by means of baffle fittings or baffle plates or stones or screens, in particular each made of refractory material; and / or wherein the gas is admitted by means of the inlets at different height levels, in particular with the mixed gas inlet at a height level above the combustion air inlet, in particular by means of the mixed gas inlet in an arrangement on a base above the floor.

16. A method for operating a coke oven device (10) for producing coke by coking coal or coal mixtures with optimized minimized nitrogen oxide emissions by means of internal thermal energy compensation

in-house gases and gases from the coke oven (G1, G4, G5)

Claims, wherein in a respective twin heating train (13) the

Coke oven device (10) with a flamed heating channel (11) and an exhaust-gas-carrying heating channel (12) by means of at least one coupling passage (14.2) through a partition (14) an internal exhaust gas recirculation is set on at least one circular current path around the partition, in the lower area at least two gases from the following group are admitted at the bottom (5.4) of the respective twin heating flue: coke oven gas (G1a),

it is noted that a recirculation exhaust gas (G4) of the exhaust gas recirculation through a central section (30) located at least in sections below the paired heating channels and the heating channel (11) flamed with gas with the exhaust gas leading downwards

flowing through the heating channel (12) connecting the coupling channel (20) in such a way that the recirculation gas (G5) is introduced essentially in the vertical direction into the gas-flamed heating channel (11).

17. Use of combustion air and mixed gas inlets in one

Coke oven device (10) with a plurality of twin heating flues (13) each with two heating channels (11, 12) for producing coke by coking coal or coal mixtures at least with mixed gas heating and optionally also with temporary coke oven gas heating, in particular in a coke oven device (10) after a of the preceding device claims, wherein in a respective twin heating duct (13) by means of at least one coupling passage (14.2) an internal exhaust gas recirculation on at least one circular flow path is set, the inlets to minimize nitrogen oxide emissions by internal thermal energy balance in a ratio (y1: y2) of the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) to the distance (y2) the inner edges of the partition walls (14) of a respective heating duct (11, 12) are arranged by at least 10%, the distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) being at least 50mm amounts.

18. Use combustion air and mixed gas to minimize

Nitrogen oxide emission through internal thermal energy balancing in heating ducts of a plurality of twin heating flues (13) of a coke oven device (10), in particular in a coke oven device (10) according to one of the preceding device claims, wherein in a respective twin heating flue (13) by means of at least one coupling passage (14.2) an internal exhaust gas recirculation is set on at least one circular flow path, the combustion air and the mixed gas in a distance ratio (y1: y2) of the distance (y1) between their inlets (16, 17) and the distance (y2) of the inner edges of partition walls (14) of a respective heating channel (11, 12) of at least 10% and at a distance from one another of at least 50mm, in particular at a flame temperature with mixed gas heating of a maximum of 1,700 ° C or a maximum of 1,600 ° C or a maximum of 1,500 ° C, in particular at a nozzle stone temperature of at least 1,300 ° C or at least 1,320 ° C.