DE102019206628A1 - Coke oven device for producing coke and method for operating the coke oven device and use - Google Patents

Abstract

The invention relates to a coke oven device (10) for producing coke, with a plurality of twin heating flues (13) with heating channels, each of which is separated from one another in pairs by a partition (14) and sealed off by two opposing rotor walls (15), the lower one being At least one inlet from the following group is provided in the area at the bottom (5.4) of the respective heating channel: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17); where 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 50mm, with at least one of the combustion air and mixed gas inlets (16, 17) being eccentric is arranged 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). The invention also relates to a corresponding method.

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 remains high worldwide and is estimated to remain high in the future, as described in the following publication, for example: K. WESSIEPE 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 increasingly stringent environmental criteria, several hundred coke ovens are built and put into operation every year. 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, individual optimization measures have to be 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 _x 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 that were permitted in 2018 or that are still tolerated in existing plants can be mentioned, particularly for European territories: 500mg / Nm ³ , corresponding to approx. 250ppm at 5% oxygen O2. However, this limit has been in place for many years and may be further reduced in many countries in the near future. 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 well 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 let it rise above 1,250 ° C. 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: component Blast furnace gas Coke oven gas Mixed gas from blast furnace and coke oven gas hydrogen 0 ... 6 50 ... 60 4 ... 10 oxygen 0 ... 4 0 ... 3 0 ... 3 nitrogen 35 ... 75 2 ... 10 40 ... 55 Carbon monoxide CO 25 ... 30 2 ... 10 15 ... 30 Carbon dioxide CO2 10 ... 25 0 ... 5 10 ... 20 methane <1 15 ... 35 0 ... 5 Higher hydrocarbons <1 0 ... 5 0 ... 2 Hydrogen sulfide <1 0 ... 1 <1 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 generated in coke ovens during the coking process and have a high heat content (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 plant after appropriate removal of impurities or valuable substances. 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. over 100 required variations). 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 staging 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 channels arranged in pairs next to one another, in particular in a vertical orientation, are coupled to one another in that the gas is returned from the flamed heating channel into the non-flamed heating channel, be it only at an upper / lower reversal point, or be it both above and 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 paired heating ducts (twin heating flues), the mean nozzle stone temperature must be controlled or limited, and must be kept at a moderate level (e.g. by lowering the local flame temperature (with high-gas heating above 2000 ° C, with mixed gas heating below 2000 ° C) 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. 110mm to 150mm. 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). If 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 height level at which 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 passages can also be arranged up to a height of 1,000 mm above the burner level.

The height position of a lower passage or a pair of lower 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, is in the case of high-gas heating z .B. 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 previously indicated, 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 corresponding 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, every measure also has possibly 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, there is a high lateral internal pressure (driving pressure of the charcoal charge), especially on the 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 to the furnace chamber expand, 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) oven 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 a high priority for the measures required to reduce emissions outlined above. 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 direction of expression (depth y ) each heating channel is, for example, approx. 400 to 550mm long or deep (middle to middle). A rotor wall thickness is, for example, in the range from 80 to 120 mm. A binder wall thickness is, for example, 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. WESSIEPE also considers measures on ovens with twin heating flues, although 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.

The patents DE 34 43 976 C2 and DE 38 12 558 C2 are mentioned 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.

In the Offenlegungsschrift CN 107033926 A From August 2017, an arrangement with twin heating flues with graduated introduction of combustion air and with circular flow openings is described, which are arranged on both sides of the step 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 the 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 also being 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 furnaces described here are usually operated with self-ignition (especially at over 800 ° C), so that the corresponding measure for cooling or lowering the gas temperature only under narrow boundary conditions or only in a narrow temperature range can take place, in particular to avoid the burn 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.

Furthermore, the patent application DE 40 06 217 A1 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 furnace 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 the year 2018 In any case, it still seemed unthinkable that the requirements described above could be met, in particular with the internal, primary measures described above, either alone or cumulatively. Lowering NOx emissions by a significant 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 with reasonable effort, i.e. not in an economical manner.

Despite 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 in order to possibly give the option manage 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 operator, 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, measures aimed at coke oven gas heating should therefore be around 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 measures aimed at coke oven gas heating also have the disadvantage of increased pressure losses in the oven, 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 gases G1 , G4 , G5 by measures internally on the coke oven device, with a multitude of twin heating flues each with a heating channel flamed with gas and a heating channel through which exhaust gas flows downwards, which heating channels are separated from each other in pairs by a partition wall (also known as a binder wall) and by two opposing runner walls from a respective one Furnace chambers are sealed off, with the paired heating channels are 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 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 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 is. This enables a reduction of 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, a relative minimum distance being defined with respect to the entire y-extent of the respective heating duct. According to the invention, an absolute minimum distance is also defined (y1min = 50mm). This enables an advantageous influence on the temperature and flow profile. The minimum distance y1 lies, 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. In the context of the present invention, this also provides further structural or process-related variables (or degrees of freedom) for adapting a furnace to specific applications.

For example, a distance y1 provided in the range from 100 to 300mm. For example, a relationship y1 / y2 chosen in the range between 30 and 60% (or 0.3 and 0.6). The relationship y1 / y2 can also be significantly larger, for example up to 90% (or 0.9). The ratio is preferred y1 / y2 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 in the distance y1 can be used as an effective measure for NOx optimization. In particular, there was a positive effect with the size according to the invention or the range of the distance according to the invention y1 on the NOx formation can be detected in a systematic way. So far, the furnace manufacturer has suggested a variation in the distance y1 apart. In particular, this distance was not identified as a measure for NOx savings. There was therefore no reason for such a purposeful variation of the distance y1 , especially since at first glance a variation in distance 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 assigned to pig iron production in the blast furnace, but rather to the underlying process chain of the 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 , especially below 15%, can be advantageous especially 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 with a structural design 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 flues) and with a structural design 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 flue gas flowing through the recirculation openings, at least partially a combustion-inert intermediate layer can be formed in the horizontal direction to at least one of the admitted media (gas and / or air). It has been shown that this results in the combustion in vertical Direction can be delayed, which can have a beneficial 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. For reasons of stability in particular, the next but one layer above (e.g. vertical layer number 3 ) further openings are provided, in particular parallel (symmetrical) to position number 1 can be arranged.

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, # 11, ... (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 or the (lowermost) recirculation passages are arranged in a height position less than 2 m 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 is y1: y2 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 is y1 at least 100mm, for example at least 150mm, for example 200 to 250mm. This allows the gas flow paths to be set and regulated more individually.

According to one embodiment, the ratio is y1: y2 at least 35%, in particular a maximum of 50% or a maximum of 60% or a maximum of 70%. It has been shown that the distance y1 starting from 10% or 15% can be further increased or also maximized without this having to be associated with noticeable disadvantages with regard to 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 is y1 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 is y1 maximum 350mm or maximum 375mm. It has been shown that distances y1 greater than 400mm 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 is y1 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 for 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. ) is at least 50cm ² in plan view, in particular at least 200cm ² or at least 300cm ² or at least 500cm ² or at least 700cm ² or at least 900cm ² , in particular between 1,000cm ² and 1,350cm 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, as will be explained in more detail in connection with the description of the figures. 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 at different distances on the respective bottom x1 , x2 arranged to at least one of the two opposing rotor walls of the respective twin heating cable, 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 can be adjusted comparatively freely to the two rotor walls. The respective openings / inlets can also be of different sizes both in the x and in the y direction and 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 of the combustion air-inlet and / or the mixed gas inlet of the respective floor at least 30cm or at least 50cm ^{2 2.} This can also further promote a flattening of temperature peaks.

According to one embodiment, the cross-sectional area of the combustion air inlet and / or the mixed gas inlet is a maximum of 500 cm ² or a maximum of 400 cm 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 by a factor 2 to 3 larger than the usual cross-sectional areas. 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 51mm x 144mm, i.e. only approx. 75cm ² .

In particular, a connecting opening for the exhaust gas or flue gas flow reversal (passage) can also be configured with a passage area of at least 500 cm ² . Last but not least, this also makes it possible to keep undesired 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 of the mixed gas inlet is rectangular or elliptical or round. The geometry can e.g. can 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 of 1000 cm ² . As a result, 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 is 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 in each case to the distance y1 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.

ITEM1 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, with nitrogen oxide emissions minimized by internal thermal energy balancing, with a large number of twin heating flues with heating channels in pairs, each of which is separated from one another by a partition wall are sealed off by two opposing rotor walls, with at least one inlet from the following group being provided at the bottom of the respective heating channel: 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 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 -Inlet to the distance of 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 is at least 50mm, with at least one of the combustion air and mixed gas inlets eccentrically larger at an x distance A factor of 0.7 of the absolute x-extension of the heating channel is arranged between opposing rotor walls; 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.

ITEM2 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 and with nitrogen oxide emissions minimized by internal thermal energy balance, with a large number of twin heating flues with heating ducts, which are separated from each other in pairs by a partition and through two opposing rotor walls are sealed off, with 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 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 from 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 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 opposing rotor walls ; in particular the coke oven device described above; furthermore the distance y1 is at least 100mm, in particular at least 150mm, the combustion air inlet and the mixed gas inlet being offset in the x direction with respect to the opposite rotor wall. This provides many of the aforementioned advantages.

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 using gases from the steelworks (blast furnace gases) and coke oven gases through measures internally at 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 admitted are: coke oven gas, combustion air, mixed gas, the group of admitted gases comprising at least the two gases combustion air and mixed gas; the combustion air and the mixed gas on flow paths at a distance on the respective floor y1 in relation to each other y1: y2 of at least 10% to the distance y2 of the inner edges (inner surfaces) of the partition walls of a respective heating duct, the distance y1 of these two embedded flow paths is at least 50mm, 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 duct between opposite 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 as 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. Until now, many constructions have usually had a two-stage temperature profile across the height, each with a comparatively pronounced "belly" or a comparatively blatant one Unequal 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 admitted at least approximately in the vertical direction at the respective floor by means of the respective inlet. 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 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 circulating current path being set in a respective twin heating flue by means of at least one coupling passage, the inlets in a ratio to minimize nitrogen oxide emissions by internal thermal energy compensation y1: y2 of the distance y1 are arranged between facing edges of the combustion air inlet and the mixed gas inlet at a distance of at least 10% between the inner edges of the partition walls of a respective heating duct, the distance y1 between the facing 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 circulating current path, the combustion air and the mixed gas in a spacing ratio y1: y2 of the distance y1 between their inlets and the distance y2 the inner edges of partition walls of a respective heating channel of at least 10% and at a distance of at least 50mm from one another, 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.

Further features and advantages of the invention emerge from the description of at least one exemplary embodiment on the basis of drawings and from the drawings themselves

Figure list

• 1A , 1B , 1C , 1D , 1E , 1F , 1G , 1H each in a schematic representation in sectional side views and plan views twin heating ducts or coke ovens according to the prior art;
• 2A , 2 B , 2C , 2D , 2E each in a schematic representation in sectional side views and in plan views twin heating ducts or coke oven devices according to exemplary embodiments;
• 3 , 4th , 5 , 6th , 7th each in a schematic representation in plan view of a relative arrangement of inlets according to an embodiment;
• 8th a schematic representation in plan view of a relative arrangement of inlets according to the prior art;
• 9 in a schematic representation in plan view, constructive dimensions for twin heating flues;
• 10A , 10B , 10C each in a schematic representation in plan view of a relative arrangement of the inlets relative to a more distant lower recirculation passage according to an embodiment;
• 11 in a schematic representation in plan view a relative arrangement of the inlets relative to a single lower recirculation passage according to an embodiment;
• 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.

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.

DETAILED DESCRIPTION OF THE FIGURES

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

The paired heating channels are each separated by a coupling partition (truss wall) 4th separated from each other, in which a coupling passage above and below 4.4 is provided over which a circulating current 9 can be realized by recirculated exhaust gas. Adjacent twin heating flues are through a partitioning wall 4a Completely sealed off from one another without any openings.

In the partitions 4th , 4a is each a step air duct 4.1 arranged, which has at least one combustion stage 4.2 or the corresponding inlet or outlet is coupled to the heating channel. The respective combustion level 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 indicates the width of the furnace 1 , the y-direction denotes the depth (or the horizontal push-out direction in a horizontal chamber furnace), 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, which is arranged centrally in the x- and y-direction with respect to the inner surfaces / inner walls (not explicitly identified; for example in the center of the respective circular flow-around partition, in particular in the center of a centrally arranged step air channel). The term “centric” or “center” here refers to a center in the xy plane, and the term “centered” or “center” here refers to the height direction ( z ).

In the so-called burner level 5.4 or a plurality of inlets are arranged at the bottom of a respective heating duct, namely a (first) combustion air inlet 6th , especially for coke oven gas heating, and another combustion air inlet 7th , especially for mixed gas heating, and a coke oven gas inlet 8th . Gas introduced through these inlets flows on the wall surfaces 4.3 the partition walls and on the inner walls of the rotor walls upwards.

As the typical temperatures at the coke oven for the furnace builder / operator 1 can be called: 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 temperature profile that is as homogeneous as possible T2 (especially in the vertical direction).

With reference to the 1F to 8E the individual gas flows are described below. The gas flow G1 indicates newly admitted or supplied heating gas or combustion air. The gas flow G1 can be a gas stream G1a (Coke oven gas) and / or a gas stream G1b (Mixed gas) include. The gas flow G4 identifies recirculation exhaust gases which are returned or circulated. The gas flow G5 indicates gas or air from a respective combustion stage 4.2 , 11/14 , and the gas flow G6 indicates exhaust gases that are discharged from the respective heating duct or heating flue.

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

1G shows schematically a heating differential 5.6 with individual openings 5.61 , via 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 flues by an (intermediate) ceiling 5.7. The heating differential 5.6 is independent of the circulating current 9 . A distance E. between heating differential 5.6 and passage 4.4 can be designed individually for each furnace. The reference number E. can also characterize a cross-sectional area. The cross-sectional area is preferably E. at least 300cm ² or at least 340cm ² .

On an illustration of the under the burner plane 5.4 The central structure of the furnace is deliberately left out for the sake of clarity. The supply of gases and the regulation of the volume flows can take place in the central building.

The 2A , 2 B , 2C , 2D , 2E show a coke oven device 10 according to an embodiment, comprising: furnace chamber 10.2 , flamed heating channels 11 , Inner wall 11.1 , exhaust gas-carrying heating ducts 12 , Twin heating cables 13 , Partitions 14th with inner surface 14.3 , partitioning walls 14a without outlets, step air ducts 14.1 with combustion stages 11/14 , coupling passages 14.2 , Bulges 14.4 , Runner walls 15th with inner surface 15.1 , Combustion air inlets 16 , Mixed gas inlets 17th , Coke oven gas inlets 18th , Valve blocks 19th .

With reference to the 2A , 2 B , 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 2A is a schematic (in some heating channels) the paired arrangement of the inlets 16 , 17th opposite the inlet 18th .

In 2 B is shown that the inlets 16 , 17th are offset comparatively strongly outward in the x-direction (eccentric), and are comparatively strongly spaced from one another in the y-direction. The arrangement of the optional coke oven gas inlet 18th is independent of this, or can largely be chosen freely.

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

In the 2C shown passages 14.2 or the step gas inlet 11/14 The arrangement, number and geometry can also be varied according to the variants shown or discussed in the further figures.

With reference to the 8B to 8E the individual gas flows are described below. The respective gas flow path GP1 characterizes inflow paths according to the invention or flow paths for at least one of the gases introduced via the inlets G1 . 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 introduced in stages G5 .

2D particularly illustrates the comparatively large distance y1 .

2E shows a view analogous to that according to 2C . The in 2C , 2E The inflow angle illustrated, 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 used for the other inlets 17th , 18th will be realized.

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.

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

• - vergleichsweise hoher Druckverlust (z.B. im Sommer) im Heizzug: Schieber geöffnet zwecks Minimierung des Druckverlustes;
• - Regulierung von Druckverlust und Durchflüssen insbesondere zur Anpassung der Leistungskapazität der Anlage (insbesondere je nach gewünschtem Koks-Output);
• - Regulierung von Druckverlust und Durchflüssen insbesondere zur Anpassung der Betriebsparameter auf das Einsatzmaterial (Anpassung der so genannten Kohlebasis), z.B. bei zunehmendem Wassergehalt höherer Gasbedarf;

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), for example higher gas requirements 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 air inlet 16 and mixed gas inlet 17th completely overlap in the x-direction, the inlets being arranged without an x-offset and having at least approximately the same x-extension.

The 4th shows an arrangement with the inlets 16 , 17th on different x-coordinates (x1> x2) at a comparatively large distance y1 . The relationship y1: y2 ranges from 25% to 30%. Y1 is much larger than 50mm. Here is the extension y2 dimensioned with respect to the inner surface of the respective partition wall as such (per se), in particular with respect to the most distant parallel section of the partition wall, that is, independent of any optionally provided bulges 14.4 for step air ducts. Such bulges 14.4 are optionally provided in the case of comparatively narrow partition walls, particularly for reasons of stability. The y dimension (depth) is, for example, in the range from 5 to 40mm. Especially with an arrangement according to 4th the advantage of great flexibility with regard to varying operating parameters can also be ensured.

• - Parameteroptimierung insbesondere hinsichtlich Änderungen der Gasqualität: im Verlauf der Lebensdauer kann temporär oder permanent ein niederkaloriges Mischgas (insbesondere mit unteren Heizwerten kleiner als 4185kJ pro Nm³; typische untere Heizwerten von Mischgasen im Bereich von 4185 bis 5500kJ pro Nm³) zur Anwendung kommen;
• - Variation des Gas/Luft-Verhältnisses am Boden über einen vergleichsweise großen Bereich mit gutem Effekt auf die vertikale Temperaturverteilung; dies kann insbesondere bei einer erforderlich werdenden Kapazitätsänderung des Ofens oder bei veränderter Beheizungsführung oder veränderter Kohlebasis vorteilhaft sein.

4th 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.

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

The 5 shows an arrangement with the inlets 16 , 17th on comparatively clearly / strongly different x-coordinates (x1> x2) at a comparatively large distance y1 , with the inlets 18th are each arranged comparatively far in the middle in the x direction, in particular also at least approximately in the middle in the y direction. The relationship y1: y2 ranges from 25% to 30%. It is y1 greater than 50mm. The relationship x2 : x1 is, for example, 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.

• - Luftöffnung am Boden in Ausgestaltung als Düse 16 (illustriert durch runde Querschnittsgeometrie); Düsen können insbesondere bei Zugang von oben von der Decke aus einfacher zugänglich und austauschbar sein als Schiebersteine.

5 shows in particular 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 designed as 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 the mixed gas inlet 17th completely overlaps 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.

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

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

The 7th shows an arrangement comparable to that according to FIG 6th , being the offset between the inlets 16 and 17th is inverted (x1> x2). The relationship y1: y2 ranges from 25% to 30%. Y1 is much larger than 50mm. The relationship x2: x1 is, for example, 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 7th can in particular thanks to the arrangement of the air inlet 16 in the area of the recirculation openings 14.2 (especially comparable x-coordinate) the gas composition can be influenced before it is burned. In particular, the recirculated exhaust gas mixed with the air shortly after the respective recirculation opening, in particular without causing a combustion 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 embodiments according to 7th can use the air and mixed gas inlets 16 , 17th in particular be arranged without any overlap in the x direction, in particular asymmetrically to that in FIG 6th shown arrangement.

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

The 8th Figure 3 shows a prior art arrangement with the inlets 6th , 7th 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 8th is arranged on an x-coordinate in the area of recirculation openings. The distance y1 is average size, and that's the ratio y1: y2 is average size. The x-coordinate of the inlets 6th , 7th , in particular from their midpoints, is approximately half of 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 between the runner walls 15th to x1 or to x2: range from 0.4 to 0.6.

9 describes an exemplary arrangement of the openings according to the invention in the context of further structural details of a furnace. The oven division x0 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 train division y0 is in particular in the range from 400 to 550mm (center partition wall to center partition wall). The partitions 14th have, for example, a thickness (y dimension) in the range from 130 to 170mm. The runner walls 15th have a thickness (x dimension) in the range from 70 to 130mm.

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

The 10A , 10B , 10C illustrate in particular the “forward burning” operating mode, with recirculation passages being provided in pairs, for example. 10A describes an exemplary arrangement according to the invention with the inlets 16 , 17th , 18th in such a relative arrangement to the more distant lower recirculation passage 14.2 (each center point) that a quadrilateral with an area A. is stretched. 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 also illustrates the exit plane xz14 the partition 14th . In contrast, the relevant corner point of the polygon is offset inwards to the center of the wall. The area specification is therefore independent of the wall thickness of the partition 14th .

10B describes an exemplary arrangement according to the invention with the inlets 16 , 17th , 18th in such a relative arrangement to the more distant lower recirculation passage 14.2 (each center point) that a quadrilateral with an area A. is stretched. 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 , 17th , 18th in such a relative arrangement to the more distant lower recirculation passage 14.2 (each center point) that a quadrilateral with an area A. is stretched. 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), the surface area A. an advantageous range of 200 cm ² to 2,000 cm ² can be defined, particularly preferably 500 cm ² to 1,500 cm ² , in particular for comparatively large furnaces with a furnace chamber height of more than seven (7) meters, more preferably 700 cm ² to 1,500 cm ² , that is to say at heights of more than 7 meters that have become common in many applications in recent years.

11 describes an exemplary arrangement according to the invention with reference to a furnace design with only one lower recirculation passage, in particular with so-called “back-to-back” heating. The inlets 16 , 17th , 18th are so relative to each other and relative to the (single) lower recirculation passage 14.2 (each center point) arranged that a quadrangle with an area A. is stretched. 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), the surface area A. an advantageous range of 50 cm ² to 1,800 cm ² can be defined, particularly preferably 300 cm ² to 1,300 cm ² , in particular in the case of comparatively large ovens with an oven chamber height of more than 7 meters, more preferably 500 cm ² to 1,300 cm ² .

This in turn applies to large ovens with a chamber height of more than 7 m (standard for new buildings). For smaller ovens between 4m and 7m chamber height, I have again moved the lower limit for the area to be particularly protected downwards. Should this optimal area be criticized as too large, I would raise the lower limit by 200 cm2.

In the 10ff . 11 and 11, a triangle can optionally also be spanned, namely for the case that the high-gas inlet 18th on a connecting line from one of the further inlets 16 , 17th to the center of the recirculation passage 14.2 is arranged.

In the 10ff . The arrangements shown in FIGS. 11 and 11 define 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, preferably a square arrangement, the area of which is at least 50cm ² in plan view at least 200cm ² or at least 300cm ² or at least 500cm ² or at least 700cm 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 17th relative to the combustion air inlet 16 according to the state of the art. One located between these two adjacent inlets 16 , 17th resulting flow exchange section B. , in the sense of a fluidic 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 with a comparatively small y-distance and a comparatively large flow exchange area, this arrangement leads to strong mixing just above the inlets, with the effect that a high temperature (too high maximum temperature) is set and a disadvantageously high NOx -Emissions cannot be avoided or can only be avoided by means of countermeasures.

13A shows a relative arrangement of the mixed gas inlet 17th 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 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 can be delayed (in terms of time or in relation to the height direction) and / or less thorough mixing takes place. With this arrangement, the comparatively large flow exchange area is not a disadvantage.

13B shows an arrangement in which, due to the lateral x-offset, the flow exchange surface or the flow exchange section B. is reduced in size. The flow exchange section is also exemplary here B. applied orthogonally to cross connections between the inlets. The inlets overlap only very slightly or, optionally, not at all. The y-distance is comparable 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 one Temperature distribution can be ensured in particular over the height of the heating flue and optionally also in other dimensions of the heating flue. The NOx emissions can be reduced very effectively.

List of reference symbols

1

Coke oven, in particular horizontal chamber oven

2

Furnace chamber with charcoal charge

3

Runner wall

4th

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

two heating channels coupling passage (or flue gas reversal point or reversal point for heating gas)

5

Twin heating flues (arrangement of two vertical heating flues in pairs)

5.1

flamed heating duct (vertical heating duct)

5.2

exhaust gas-carrying heating duct (vertical heating duct)

5.3

Inner wall

5.4

Burner level or floor of a heating duct

5.6

Heating differential

5.61

single opening in the heating differential

5.7

(Intermediate) ceiling of a heating duct

6th

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

7th

further combustion air inlet or inlet for mixed gas heating

8th

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

Furnace 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)

14th

Partition wall or truss wall

14a

partitioning wall without openings

14.1

Duct or step air duct in partition

11/14

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

15th

Runner wall

15.1

Inner surface of the runner wall

16

(First) combustion air inlet or air inlet, in particular for coke oven gas heating

17th

further combustion air inlet or mixed gas inlet, in particular for mixed gas heating

18th

Coke oven gas inlet or coke oven gas nozzle

19th

Slide valve

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

G1b

Mixed gas

G4

Recirculation exhaust

G5

Stage gas or stage air from the combustion stage

G6

Exhaust gas

GP1

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

GP4

Recirculated flue gas / flue gas flow path

GP5

Flow path of gas introduced in stages

M.

Central longitudinal axis of the respective heating channel

T1

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)

x0

Oven division

x1

Distance between the combustion air inlet and the opposite wall of the rotor

x2

Distance of the mixed gas inlet to the opposite wall of the rotor

xz14

Exit level partition

y

Depth or horizontal push-out direction (longitudinal extension of the runner wall)

y0

Heating train division

y1

Distance between 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)

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 3443976 C2 [0032]
• DE 3812558 C2 [0032]
• CN 107033926 A [0033]
• DE 3916728 C1 [0034]
• DE 4006217 A1 [0038]

Non-patent literature cited

• K. WESSIEPE et al .: Optimization of Combustion and Reduction of NOx Formation at Coke Chambers .... COKE MAKING INTERNATIONAL; 9, 2; 42-53; VERLAG STAHLEISEN MBH; 1997 [0002]

Claims (16)

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 balancing by means of the steel mill's own gases (G1, G4, G5), with a large number of twin heating cables (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 each other in pairs by a partition (14) and by two opposing rotor walls (15) from a respective furnace chamber (10.2) are sealed off, wherein the paired heating channels are fluidically connected 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 circular flow path are coupled together, 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, at least one of the Combustion air and mixed gas inlets (16, 17) are arranged 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). 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%. 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 further away from the combustion air and mixed gas inlet, define a triangular or square arrangement, the area of which ( A) is at least 50 cm ² in plan view, 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 . Koksofenvorrichtung according to any one of the preceding claims, wherein (17) at least 30cm be at the respective bottom of the cross-sectional area of the combustion-air inlet (16) and / or the mixed gas inlet ² or at least 50 cm ^2; and / or wherein the cross-sectional area of the combustion air inlet (16) and / or of the mixed gas inlet (17) is a maximum of 500 cm ² or a maximum of 400 cm ² ; and / or wherein the cross-sectional geometry of the combustion air inlet (16) and / or of the mixed gas inlet (17) is rectangular or elliptical or round. Coke oven device according to one of the preceding claims, wherein 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 slide block and / or by means of at least one replaceable / detachable nozzle. 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 flue in the upper region is set up for the mutual transfer of gases, the recirculation passage (14.2) having 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. Coke oven device according to one of the preceding claims, wherein the combustion air inlet (16) and the mixed gas inlet (17) offset in the x-direction with respect to the opposite rotor wall (15) are arranged; 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 rotor wall (15) in each case to the distance (y1) is at least 90% and / or a maximum of 290%, in particular between 200% and 250%. Coke oven device according to one of the preceding claims, wherein the combustion air inlet (16) is arranged further inside closer to the opposite rotor wall (15) than 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). Coke oven device (10) 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 cables (13) with heating channels in pairs, each of which is separated from one another in pairs by a partition (14) and by two opposing rotor walls (15) are sealed off, with at least one inlet from the following group being provided on the bottom (5.4) of the respective heating channel: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17); 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, the ratio (y1: y2) of the distance (y1) at the respective base (5.4) 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) is at least 50mm, with at least one of the combustion air and mixed gas inlets (16, 17) being eccentric at an x-distance greater than a factor of 0.7 of the absolute x-extent of the heating duct between opposite ones Rotor walls (15) is arranged, and wherein the paired heating channels fluidically by means of at least two lower coupling D. Passages are coupled to one another, 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 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. Coke oven device (10) 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 cables (13) with heating channels, which are separated from one another in pairs by a partition (14) and by two from one another 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 duct is provided with at least one inlet from the following group: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17); where 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 50mm, with at least one of the combustion air and mixed gas inlets (16, 17) being eccentric is arranged 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); in particular 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). 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 gas from the steelworks and the coke oven's own gases (G1, G4, G5) 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 (13) of the coke oven device with a flame Heating duct (11) and an exhaust-gas-carrying heating duct (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 the bottom (5.4) of the respective Zwillingsheizzuges at least two gases from the following group are admitted: coke oven gas (G1a), combustion air (G1), mixed gas (G1b), the group of admitted gases comprising at least the two gases combustion air (G1) and mixed gas (G1b); characterized in that the combustion air and the mixed gas on flow paths at a distance (y1) from one another in the ratio (y1: y2) of at least 10% to the distance (y2) of the inner edges (inner surfaces) of the partition walls (14) on the respective floor (5.4) of a respective heating duct (11, 12), the distance (y1) between these two flow paths being at least 50mm, with combustion air and / or mixed gas eccentrically at an x-distance greater than a factor of 0.7 of the absolute x-extent of the heating duct between opposite runner walls (15) are embedded. Method according to the preceding method claim, the cross-sectional area of the combustion air inlet (16) and / or the mixed gas inlet (17) being adjusted with regard to geometry and / or size, in particular by means of at least one slide block. Method according to 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, in particular 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. Method according to 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 baffles 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. Use of combustion air and mixed gas inlets in a coke oven device (10) with a large number of twin heating flues (13) each with two heating ducts (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) according to one of the preceding device claims, with an internal exhaust gas recirculation on at least one circulating current path being set in a respective twin heating duct (13) by means of at least one coupling passage (14.2), the inlets being set 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) of the inner edges of the partition walls (14) of a respective heating duct (11, 12) of at least 10% are arranged, whereby de The distance (y1) between the facing edges of the combustion air inlet (16) and the mixed gas inlet (17) is at least 50mm. Use of combustion air and mixed gas to minimize nitrogen oxide emissions 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) an internal exhaust gas recirculation is set on at least one circular flow path by means of at least one coupling passage (14.2), 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 ) the inner edges of partition walls (14) of a respective heating channel (11, 12) are let in by at least 10% and at a distance of at least 50mm from one another, in particular with 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, especially at a nozzle stone temperature of at least 1,300 ° C or at least 1,320 ° C.

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