DE102017216437A1 - Coke oven apparatus having eccentric inlets for producing coke, and methods of operating the coke oven apparatus, and controller and use - Google Patents

Abstract

The invention relates to a coke oven device (10) for producing coke by coking coal with minimized nitrogen oxide emissions by internal measures, with a plurality of twin heating trains (13) each with a flamed heating channel (11) and an exhaust-carrying heating channel (12), which heating channels respectively separated by partitions (14) and rotor walls (15), wherein the pairwise heating channels are fluidically coupled to each other by means of an upper coupling passage (14.2) for internal exhaust gas recirculation on an outer circular path (19, 19.1), wherein in the lower area at the bottom (5.4 at least one inlet is provided from the following group: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17); wherein at least one of the inlets (16, 17, 18) is more eccentrically arranged with respect to the width (x) of the heating channel than at least one of the passages (14.2) and defines a flow path (G1, G1a) arranged more eccentrically than the exhaust gas recirculation (19) , This allows reduced nitrogen oxide emissions. The invention further relates to a method for operating the coke oven device.

Description

The invention relates to an apparatus and a method for producing coke and a control device and corresponding uses. In particular, the invention relates to an apparatus and a method according to the preamble of the respective independent claim.

The demand for coke ovens is still high worldwide and will continue to be high for the future, as described in the following publication: 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 , The planning and construction of coke ovens has to be done a long time horizon, especially since the service life of a coke oven can be quite long, so it is important to know what environmental improvements can be realized in coke ovens in the next few years. Every year, despite ever stricter environmental criteria, several hundred coke ovens are newly built and put into operation. Nevertheless, most politicians are now well aware that energy production using coke ovens is not very environmentally friendly. The construction of new coke ovens, or even the operation of existing coke ovens, is therefore subject to increasingly stringent emission requirements from many quarters, in particular with regard to nitrogen oxides (NOx). In this context, there are numerous efforts to improve the efficiency of coking or the environmental friendliness, as can be found in the following publication and the technical articles cited therein: AJ Nowak et al .: CFD model of coupled thermal processes within the coke oven battery .... Computer Assisted Mechanics and Engineering Sciences, 17: 161-172, 2010 , This publication deals with the simulation of previously known optimization measures.

As currently permissible or still tolerated emission limits in existing plants can be called: 500mg / Nm ³ , corresponding to about 250ppm at 5% oxygen O2. As future limits can be mentioned: about 350mg / Nm ³ (about 170ppm at 5% O2) in Europe, or soon probably even only about 200mg / Nm ³ in Asia, especially Japan, Korea, Taiwan and China. In other words, the NOx emission should sink as soon as possible by half or more. However, some environmental authorities are already calling for an upper limit of only about 100mg / Nm ³ , especially in Asia, which would be equivalent to a factor of 5. In view of increasingly stringent requirements, especially for diesel-powered vehicles, it must also be expected for Europe that the permissible limit value will be even lower than 350 mg / Nm ³ within a short time.

Nitrogen oxides are released in particular by the flue gas generated by Koksofengasverbrennung or formed during combustion, in particular from a nozzle stone temperature (in the exhaust-carrying heating channel on the ground) of about 1,250 ° C (so-called thermal NOx formation). The thermal NO x formation is favored or fanned exponentially with higher temperature, so that the emission of nitrogen oxides is strongly determined by the thermal conditions in the coke oven. It is known that, in particular in the vertical, flue-gas-carrying heating cables of the coke oven, it is possible to influence the NOx emission by setting a specific temperature regime. The rule of thumb is that the higher the temperature, the stronger the NOx emission. An oven operator is thus endeavored or forced by environmental specifications to keep the temperature as low as possible, in particular not to let rise above the limit of 1250 ° C. However, the furnace operator is also interested in an efficient coking process and wishes to have an operating mode at nozzle brick temperatures of up to 1,325 ° C; The efficiency of coking increases with temperature, and the higher the operating temperature, the more compact a furnace battery can be designed with the same output. Example: Instead of 100 ovens, only 95 to 98 ovens have to be built at a higher operating temperature, corresponding to an equipment saving of 2 to 5 percent (lower investment volume, up to 5% less plant costs, eg with regard to an investment volume of 100 to 800 million . Euro).

To reduce the NOx emission is therefore very reluctant to realize during the coking a lowered temperature level or to avoid temperature peaks in the heating, in particular by adjusting the mode, because this brings with it losses and makes the coke production uneconomical. For the kiln operators it is therefore rather not interesting or not feasible to operate the coke oven in the optimal operating condition. Consequently, it is accepted that the NOx emissions remain disadvantageously high. However, the kiln operator knows that if it were possible to keep the heat energy input constant at a comparatively moderate, lowered temperature, this would have a positive effect on NOx emissions with a comparable output.

These boundary conditions must be considered by a kiln operator for different types of coke ovens. In particular, a differentiation is made according to the expressing direction of the coke between vertical chamber furnaces and horizontal chamber furnaces Horizontal kilns are coking batch by batch. After coking, the coke is expressed in the horizontal direction (batch operation). In contrast, the coal in vertical chamber furnaces continuously in vertical direction and discharged (Conti operation). The present invention relates in particular to horizontal chamber furnaces.

Oven chambers usually have a height in the range of 4 to 8.5m, wherein the height of the furnace chambers or heating channels is also specified by the mode of operation. The height influences the pressure difference in the heating channel. 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 altitude, because only then should it be possible to set an efficient operating condition without too much increase in NOx emissions. The temperature gradient should be as much as possible smaller than 40K or 40 ° C, in particular at a temperature in the furnace chamber in the range of 1,000 to 1,100 ° C. A temperature maximum well above the average temperature would promote thermal NO x formation. Thus, a coke oven can be operated at an optimum compromise of high output and low NOx emissions if the temperature remains homogeneously just below the temperature at which thermal NOx formation occurs.

The simulation of operating conditions is a useful tool to better assess the effects of individual optimization measures. However, a coke oven is a comparatively complex system, with corresponding simulation effort. For example, a new design with a new way of gas routing may require several weeks of calculation per calculation, so that even in simulations, a workload of several years (for example, over 100 required variations) may arise. Not only a trial of new measures on an industrial scale must therefore be carried out under limited possibilities, but also a simple constructive measure must be checked for cost reasons first in numerous aspects, before this measure can be examined more closely by simulations. As a result, design variations on existing furnace designs tend to be carried out in a very moderate, conservative manner.

So far, directly on the coke oven or on the constructive design of proven measures that should work even with optimized performance mode, usually the internal pressure differential driven or driven by temperature and density differences flue gas recirculation from the downwardly flowed through in the heating (internal circulation of a partial volume flow of the flue gas , so-called circular stream), and / or the gradation of the combustion air, so the introduction of combustion gas from partitions or binder walls in different height positions into the heating cables. The stages take place in particular with regard to the following criteria: maximum gas collection chamber temperature in the adjacent furnace chamber above the coal charge must be less than 820 ° C; Ceiling surface temperature must be at least equal to 60 ° C; Furnace chamber wall internal temperature difference <= 40K, in particular between the height positions 500mm above the furnace bottom / burner level and 500mm below the furnace chamber upper edge.

A Kreisstromführung (partially at one end of the heating channel or in full circle) is usually realized in so-called twin heating trains. Paired side by side heating cables or heating channels, in particular in a vertical orientation are coupled to each other by the gas is returned from the flamed heating channel in the non-flamed heating channel, either only at an upper / lower reversal point, or be it both above and below , In a horizontal chamber furnace can be provided in the ejection direction about 24 to 40 heating channels, so about 12 to 20 pairs of twins. An optionally realizable circulating current can form autonomously due to the pressure differences, ie without additional active fluidic control or support.

The optimization of a circulating current control, especially for the purpose of homogeneous heat distribution, began in the 1920s on an industrial scale. Since the 1970s, the influences of the circulating current system on NOx emissions have been studied in detail.

The configuration hitherto used in most cases coke ovens with Kreisstromführung can be described as follows: In pairwise heating channels (twin heating) is ascending in the flow direction, ie in the flamed heating channel, a heating gas out and burned in particular multi-stage, which then as a flue gas through the parallel, exhaust-carrying heating channel is guided down to the bottom and sucked out there, with a partial volume flow of the inert (burnt) exhaust gas in the cycle back into the leading up, flamed heating channel. The heating channels can be coupled to each other at the upper and lower ends in each case by means of an exhaust gas recirculation opening or a passage, in particular in the region of the bottom of the furnace chamber at least approximately at the same height level as the Inlets. As a result, the average nozzle stone temperature in the heating train can be controlled and maintained at a moderate level, in particular by lowering the local flame temperature (with strong gas heating above 2000 ° C., with mixed gas heating below 2000 ° C.) (eg at a nozzle brick temperature of 1240 to 1300 ° C), with the effect that the NOx emissions can be lowered. For example, the following arrangement (height position) of the lower passage can be called: between 0mm (ie directly at the level of the burner level) to 300mm above the burner level. The cross-sectional area is usually given by a layer height of about 120mm. If necessary, the lower passage can be closed in the bottom arrangement by means of a roller which can be rolled on the burner level in front of the passage. Advantageously, the passage is realized by means of a recess in a wall layer (gap or missing stone).

Such arranged in pairs and aligned in the vertical direction heating channels or twin heating trains thus allow for relatively little effort influencing the temperature profile, especially for specific adjustment of the circulation of flue gas.

There are always two types of heating cables / heating channels: upflowed, flamed Heizkanal; Downstream, exhaust-carrying heating channel. The pairwise heating channels are connected to one another in the upper region via a free opening cross-section, that is to say a passage through which the heating channels are fluidically coupled to one another. A partial volume flow of the flue gas, which is normally conducted back into the flamed heating channel, is in the case of high-temperature gas heating, e.g. 30 to 45% of the total flue gas volume produced in the upflow channel. An example of this arrangement of twin heating systems with circulating current is the so-called Combiflame heating system, which has been established since the late 1980s. In this case, a combination of the air grading was carried out with the Kreisstromführung. Previously until the mid-1980s was either an air classification (gasoline system) or a Kreisstromführung (Koppers system).

As far as in the present description of a single passage is mentioned, may also be a pair of passages meant, which are arranged in pairs in the same height position.

As indicated above, combustion can also be graded by passing gas or air via at least one stepped air channel in at least one height position above the burner level (bottom) into the respective heating cable, or by discharging corresponding exhaust gas. The staged combustion can be combined with the circular current flow.

Specifically, the measures are considered directly on the coke oven, so measures for thermal optimization, in particular by an optimized way of media management, the structural design of the coke oven and, consequently, the stability of the coke oven is of great relevance, in particular the structural design of the individual walls a respective furnace chamber and the respective Heizzuges (rotor walls, partitions). Small measures on the design structure can have great effects on the temperature balance and the coking process. However, any measure may also have very adverse side effects to avoid, e.g. on the statics of the heating walls, on the flow resistance, or the ultimately adjusting flow rates and temperature profiles. It is therefore to be expected that changes to the construction described in more detail below can only be carried out within a narrow tolerance range. In particular, the skilled person is faced with the task of risking by new measures no weakening of the Heizwandverbundes. Depending on the operating condition, high lateral forces can act on every wall. For example, after about 75% of the cooking time, a high lateral internal pressure (driving pressure of the coal charge) in particular on rotor walls at a height of about 1m above the burner level, which pressure can even cause that joints widen and thereby undesirable bypass flows (in Connection with Koksofengasüberertritten and the concomitant CO formation) between individual Heizzügen and (adjacent) furnace chambers arise. The equilibrium of the gas mixture is thereby disturbed: In particular, only an insufficient amount of air is available for additional gas quantities to be burned in the heating channel. Also lead different filling times, for example, each offset by 12 hours, in the adjacent furnace chambers to different lateral forces in the respective walls. The stability of the furnace is therefore a high priority also for measures to reduce emissions. High stability is usually achieved by a tongue and groove arrangement of the stones. This construction is also preferred in view of tightness to avoid bypass flows and pre-combustion.

In a battery having a plurality of furnace chambers, such as 40 or 60 furnace chambers, the furnace chambers are delimited by rotor walls opposite gas-conducting heating channels, in particular on a relatively narrow end face of the respective channel, in particular by two along the entire respective furnace chamber extending opposite rotor walls. The individual heating channels are thereby separated from each other by so-called binder walls (partitions), which extend in particular orthogonal to the two rotor walls between the rotor walls, in particular on the relatively wider side of the furnace chambers. Three binder walls separate two channels from each other or a twin heating cable from another twin heating cable. A respective heating channel is thus delimited by two rotor wall sections and by two binder walls. In the ejection direction (depth y) a respective heating channel is about 450 to 550mm long or deep (middle to middle). A rotor wall thickness is for example in the range of 80 to 120mm. A binder wall thickness is for example in the range of 120 to 150mm.

The term "binder wall" has established itself in common usage. In the present specification, this term is used interchangeably with the term "partition", in particular to make it clear that a rotor wall and a binder wall / partition can be made in the same construction, namely by each strung stones on its narrow side. The "rotor wall" of a horizontal chamber furnace can also be described as a longitudinal wall arranged longitudinally in the ejection direction, and the "binder wall" can also be described as a transverse (separating) wall arranged transversely to the direction of ejection.

On the underside of a respective heating channel combustion air openings and mixed gas openings are provided, the function of which can be selected or adjusted depending on the type of heating (mixed gas or Kokosofengasbeheizung). At the bottom opens a Koksofengasöffnung in the heating channel. In a circular flow guide, in each case 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 cable with a circular flow guide is formed. The volumetric flow through the exhaust gas recirculation openings can optionally be regulated, in particular by means of an adjusting roller arranged on the bottom in the burner plane and displaceable there. Stepped gas ducts are provided in the binder walls, which introduce combustion air (step gas) into the furnace chamber at one or more height positions (air stage or binder wall opening). As a common ratio of the volumetric flows introduced into the furnace chamber may be mentioned: 30% through the bottom combustion air inlet, 30% through the bottom mixed gas inlet, and 40% through the at least one step gas inlet (binder wall opening). This ratio can be set analogously 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, such as a heating differential, may be formed to adjust coking parameters. The bypass flow can be sealed off from the heating cables via a particularly horizontal wall or ceiling, in which ceiling passages are provided, which can be covered for example by means of slide blocks or can be adjusted with respect to the cross section.

The aforementioned publication by K. Wessiepe also considers in particular measures on furnaces with twin heating trains (heating trains coupled to one another at least by means of an upper passage), wherein it was already worked out in the nineties that the so-called circular flow arrangement has advantages with regard to the lowest possible NOx Concentration can deliver.

The patents can be mentioned by way of example DE 34 43 976 C2 and DE 38 12 558 C2 in which the question of an optimal cycle flow rate and a reasonable height position for stepped introduction of combustion air is discussed, in particular using the example of the Koppers Kreisstrom furnace. It also mentions that recirculation of flue gas at a height position in the area of the heat pipe allows the temperature in the respective heating train to be lowered, with the effect of reducing NOx emissions.

In the published patent application CN 107033926 A from August 2017, an arrangement is described with Zwillingsheizzügen with stepped introduction of combustion air and with circular flow openings, which are arranged on both sides of the stepped air duct.

It also experimented with a specific type of Gasleit components or packing to influence the heat distribution in the coke oven can take. For example, in the patent DE 39 16 728 C1 Beheizungsräume (heating) with internals in the form of permeable honeycomb bodies or Wabengittem or pebbles provided, where sections, certain types of flue gas duct should be advantageous. It is about improving the flow conditions in the heating chambers, and it is also proposed to supply combustion air in different height positions.

Also, certain coatings have been experimented to effectively dissipate or re-radiate heat energy from internal surfaces.

The measures described above directly on or in the coke oven or heating train can here be referred to as primary measures. For all the measures described above, it must be noted that the ovens described here are usually operated with auto-ignition (in particular above 800 ° C), so that the appropriate measure for cooling or lowering the gas temperature only under narrow boundary conditions or only in a narrow temperature range can be done, in particular to avoid that the combustion goes out.

Furthermore, secondary measures have been tested which can be carried out downstream of the coke oven in downstream plant components, for example the use of selective catalysts in the chimney (SCR or DeNOx), 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 at extremely high costs (up to 50% of the total investment for the entire coke oven) or additional maintenance. These measures are effective but in many cases too costly.

Furthermore, the patent application DE 40 06 217 A1 in which the combination of several measures comprising both measures on regenerators in the central structure of the furnace as well as measures for external flue gas circulating current is described, with the aim of homogeneous heating conditions and low NOx emission even at high furnace chambers.

Last but not least, chemical, reactive, and chemical measures are also included. the introduction of CH4 gas or increasing the humidity by injecting water has been considered. However, the injection of water or steam is not possible at any point in the chamber, but in particular only centrally at an average height position and has adverse effects on the used (silicate) materials. An increase in the regenerative preheating temperature of gas and air is a measure that is now considered exhausted and uneconomical.

However, it currently seems unthinkable that, in particular with the above-described internal, primary measures, either alone or cumulatively, the requirements described above can be met. A reduction of the NOx emissions by a factor of 2 to 5 should therefore not be feasible, at least not at a reasonable cost, so not in an economical way.

Despite the concerns expressed earlier, the present invention is directed to the optimization of coke ovens by measures directly on the coke oven or on its structural design, in particular by measures on the established heating system with heaters at least one recirculation, in particular with circular current, in particular to obtain the option to operate the coke oven in a performance-optimized operating mode without any downstream system components. This may be hoped for a great potential for improvement, with great benefits for the furnace operators, and thus also with good opportunities for enforcement of the technical concept in the market.

The object of the invention is to provide a coke oven apparatus and a method for operating the coke oven device, whereby NOx emissions can be kept low or can be minimized in existing or new plants even when operating at full load, the coke oven device advantageously low NOx -Emission level preferably without downstream system components should allow. In particular, it is an object to provide a coke oven apparatus and a method for operating the coke oven apparatus, whereby the NOx emissions can be reduced by measures internally in the heating trains.

This object is achieved by a coke oven device for producing coke by coking coal or coal mixtures, the coke oven device is adapted for minimized NOx emission by internal thermal energy or temperature compensation means of coke own gases or gas streams by primary measures internally to the coke oven device , with a plurality of twin Heizzüge each with a flamed with gas or combustion air (and therefore flowed upward) heating channel and an exhaust gas flowing downwardly flowing heating channel, which heating channels in pairs separated by a partition or binder wall from each other and by two opposing rotor walls of a respective Oven chamber of the coke oven device are sealed off, wherein the paired heating channels, in particular both at the upper and at the lower end, fluidly by means of an upper coupling passage and optionally au in each case at least one inlet from the following group is provided in the lower area at the bottom of the respective twin heating cable: coke oven gas inlet for introducing coke oven gas into the heating channel, combustion air Inlet, mixed gas inlet; wherein at least one of the inlets is arranged more eccentrically with respect to the width (x) of the heating channel than at least one of the passages and a flow path arranged more eccentrically than the exhaust gas recirculation Are defined. This measure concerns the position of the inlets. The displacement of the inlets takes place in particular in dependence on gas supply lines in a center of the furnace. By this measure with respect to the inlets, a fluidic effect can be achieved largely independently of the absolute arrangement and number of passages.

By means of the measure to use the gases admitted to influence the flow profile in the flamed heating channel, the heat distribution in the heating channel can be optimized in the first place, in particular evened out, in particular independent of a stepped introduction of step gas, and in particular independent of a recirculation in the down flowed through heating duct. In particular, the respective coke oven gas inlet can be arranged in terms of flow technology and heat energy with respect to at least one passage or further inlet. Effect: Influence on the heat distribution and gas mixing, in particular in the floor area by means of internal gas flows, ie by means of internal fluidic measures. External measures are not required. The internal measures can be purely passive measures, in particular purely constructive measures. The flow conditions can be adjusted autonomously thanks to constructive measures. This not least facilitates the operation of the device. A control / regulation of the furnace can be made comparable to the previous manner.

According to one embodiment, all inlets are in terms of width ( x ) of the heating channel arranged eccentrically as at least one of the passages. This makes it possible with good effect to form a Gasteppichs between the respective rotor wall and the recirculation, largely independent of the operation of the furnace.

According to one embodiment, at least one of the inlets, in particular all the inlets with respect to the width (x) of the heating channel are arranged more eccentrically than the lowest passages or more eccentric than all the passages. This provides a particularly strong effect at least in the bottom area, and can also allow for the influence on the mixing in the x-direction with respect to the entire height of the furnace chamber. Optionally, at least one inlet remains centric in the region of the passage or the passages, in particular in order to enable targeted influencing of the flow profile of the recirculation, in particular by delivery of inflow pulses.

These measures can be combined with the measure that at least one exhaust gas recirculation passage with respect to the width (x) of the heating channel, ie between the rotor walls, centric (closer to a central longitudinal axis of the heating channel) is arranged as at least one of the inlets and a centric or centric flow path surrounded by at least one of the gases introduced via the inlets defined. This exhaust gas recirculation flow path is arranged more centrically than the corresponding flow paths or inflow paths of the introduced gases. The displacement of the passages further toward the center may optionally be done eccentrically further outward in addition to displacing the inlets.

In this case, the y-position of the respective inlet between opposite dividing walls may preferably be at least approximately centric in each case. It has been shown that the y-position is to be chosen subordinate to the x-position and can be selected largely independently of the x-position, in particular according to the respective design advantages or as a function of a desired inflow angle.

The respective upper passage is arranged below an optionally existing heating differential, in particular in a dividing wall extending in the xz plane. By contrast, openings of a heating differential are arranged in a separating bulkhead extending in the xy plane. A lower passage is not necessarily provided.

As a result of the arrangement of the passage (s), which is as centric as possible in an xy plane, it is possible to provide an internal, circulating, circulating stream on an additional, inner, circulating circular flow path, which is surrounded externally (eccentrically) by at least one admitted gas or also by an external circulating current an external circular current path.

In the event that a recirculation via one or more lower passages should not be provided, the term "circular current" or "circular current path" can also be applied to a not completely closed, but e.g. only over 180 ° or 270 ° in the circular flow guided.

These measures make it possible, in particular, for a combustion-inert and mixed intermediate layer and cooling in the floor area, and can be carried out directly on the coke oven or on its structural design, in particular on the heating system, without the requirement of downstream plant components. As a result, in particular a temperature maximum between the burner level and the lowermost passage can be lowered. In particular, the goal can be achieved, a Temperature difference over the entire height of the heating channel to keep well below 50K, with a mean coal charge temperature in the range of 1000 ° C and a maximum temperature in the range of 1050 ° C and in any case less than 1100 ° C. By means of these measures, the potential for NOx reduction in the range of 70 to 80% with respect to the current level of 350 to 500 ppm NOx (at 5% O2) can be expected. In particular, it can be expected that a level of less than 100ppm NOx (at 5% O2) can be realized. It can also be expected that the amount of refractory material can be reduced by up to 5% per cent, with the same output. Thus, this technical solution is also very interesting in economic terms. An oven operator can operate the oven with high output, or at high nozzle stone temperatures, with comparatively low NOx emission.

The measures described in the present description can in particular be based on coke ovens with chamber operating times between filling operation and expressing operation between 15h and 28h, or on coke ovens with a heating temperature or nozzle stone temperature in the range of about 1200 to 1350 ° C.

So far, it has been customary to arrange the corresponding recirculation opening close to the rotor wall. It was also common to arrange the inlets centrally on the floor. In the context of the investigations for optimizing the NOx emissions in the context of the present invention, it has been shown that a high combustion temperature results from the fact that the coke oven gas together with the combustion air forms a very hot gas mixture already in a lower region of the furnace chamber. Due to the positioning of the inlets according to the invention, temperature peaks can be avoided. This arrangement can also be equipped with a heating differential (bypass flow) above the exhaust gas inflection points (passages). Optionally, downstream plant components can reduce the NOx emission even further, if this is still economically feasible.

The heating channel can also be described as a heating shaft. The respective heating channel is delimited at the bottom by the bottom, which floor is also referred to as the burner level, even if there are no burners used (auto-ignition especially at about 800 ° C).

As a heating channel is to be understood a term for a very specific Vertikalheizzug the two vertical heating of a twin heating. As a heating train is to understand any of the two vertical heating of a Zwwiningsheizzuges. In a respective operating state of the coke oven, a heating channel is either flared upwards or flows through downwards. If it is not relevant in the appropriate context of the explanations in which direction the gas flows, so the term heating is used here instead of the term heating channel. The term heating train can thus refer to the upwardly or downwardly flowed through the heating channel.

A coal mixture is to be understood as meaning a mixture mainly of different types of coal, wherein the mixture may, for example, also comprise at least one additive from the following group: petroleum coke, oil, bitumens, e.g. in the form of scrap tires, coal and coke dust, binding or coking aids, e.g. Molasses, oil residues, cellulosic aggregates, sulphite or sulphate compounds or lye, which mixture may also comprise biomass.

Clearances are referenced to the corresponding central longitudinal axis for references to channels, inlets, passages or nozzles, and to an inner surface for masonry or walls, unless otherwise specified.

It has been shown that the air or gas guide according to the invention can be implemented not only in twin heating trains, but also in so-called four-draft furnaces or alternative arrangements in which the concept of fluid-coupled heating cables is taken up and multiplied in each case in each paired coupling of the heating cables ,

The introduced combustion air or the heating gas serves to generate the required process heat, be it in the floor area or in specific stepped height positions.

It has been shown that the arrangement according to the invention also makes it possible to dispense with a plurality of stepped air inlets (in particular by providing only a single gas classification), in particular at furnace chamber heights of less than 8 m. A modification according to the invention of the position of the lower, bottom-side inlets thus makes it possible to reduce the constructional outlay or the complexity of the furnace elsewhere.

Preferably, the respective partition wall has a width (wall thickness) of 80 to 200 mm, more preferably 120 to 150 mm. The respective rotor wall preferably has a width (wall thickness) of 80 to 120 mm. This provides a sufficiently strong insulation and stability.

Independently of the individual optimization measures described, at least one combustion air or stepped air Inlet for introducing combustion air from a stage air passageway extending in the bulkhead into the heating channel may be provided in at least one combustion stage height position.

The lower area at the bottom of the heating train can correspond to the burner level, or even a height range over a maximum of 2 to 3 layers of brick masonry furnace (2 to 3 wall layers), at a height of each layer in the range of about 120mm. The floor area according to the definition of the present description may e.g. also extend to a height of 1200mm. Preferably, the bottom area is defined as an area from the burner level to a height of 100 to max. 800mm above the burner level. Altitudes in the present description refer to the burner level, ie to the lowest point of a respective heating channel. A lower passage is a passage defining a lower inflection point of a circular flow or a flow, in particular below an upper passage. The respective lower passage does not necessarily have to be arranged in the floor area.

According to one embodiment, all the exhaust gas recirculation passages are arranged more centrically than at least one of the inlets. This allows a particularly effective decoupling of the rotor walls. According to one embodiment, at least one exhaust gas recirculation passage is arranged more centrically than all the inlets. This allows the rotor walls to be sealed off from recirculated exhaust gas by a gas carpet of new gas introduced. According to one embodiment, all the exhaust gas recirculation passages are arranged more centrically than all the inlets. This provides a particularly effective arrangement.

According to an exemplary embodiment, at least two of the inlets comprising the coke oven gas inlet are arranged closer to the rotor walls on both sides of the coupling passages such that the circulating flow flowing out of the passages is arranged on a circular flow path closer to the central longitudinal axis of the heating channel than an inflow path the gases introduced via the corresponding inlets. As a result, in particular a too abrupt mixing of coke oven gas and combustion air or mixed gas can be prevented.

According to one embodiment, at least two of the inlets are arranged on both sides of the coupling passages closer to the rotor walls, that the respective exhaust gas recirculation passage between the inlets laterally comprises or delimited from the inlets and at least three or four upwardly flowing partial flows in the corresponding heating channel form on flow paths, at least over a certain height section (in particular in the height range of 0 to 1000mm) at least approximately parallel to each other or at least next to each other and lead to a delayed mixing in this height section. Only above this height section is a more thorough mixing.

According to an exemplary embodiment, the respective coke oven gas inlet is arranged adjacent to the corresponding rotor wall, and / or the respective combustion air inlet is arranged opposite to the coke oven gas inlet adjacent to the corresponding rotor wall. This arrangement as close as possible relative to the rotor wall allows a centric recirculation in a bottom area, which provides advantages in terms of homogeneous heat distribution. In particular, it has been found that the mixing of the individual gas streams can be delayed or shifted further into a higher vertical position.

According to one embodiment, the respective combustion air and / or mixed gas inlet is arranged adjacent to the corresponding rotor wall and the respective exhaust gas recirculation passage is arranged centrally, in particular mirror-symmetrical with respect to a central longitudinal axis in the respective heating channel. This combination of optimization measures provides a particularly strong effect.

According to one embodiment, the respective partition wall has at least one further coupling lower and / or upper passage, which is arranged in a central height position (center in z-direction) closer to the center of height of the heating channels than the outer circular current path and is adapted to form an inner inert Intermediate layer on a / the centric flow path between the gas and air flow rates. As a result, the temperature distribution can be made uniform, especially in the floor area. In particular, it has been found that temperature peaks in specific height positions can be effectively avoided by means of additional recirculation passages, in particular without risking a weakening of the heating wall assembly. In other words, a heat-insulating intermediate layer can be formed in the partition wall between the heating channels by means of which a partial volumetric flow of exhaust gas / flue gas can be conducted out of the descending heating channel and can be guided back into the ascending heating channel, wherein an intermediate intermediate-combustion-inert medium is produced by means of the intermediate layer can be generated with Verbrennungsverzögemder effect.

According to the invention, a noticeable NOx reduction effect can already be achieved by means of a single additional passage. Exhaust gas or a larger volume flow of exhaust gas can be conducted in such a way in the upwardly flowed through the heating channel, in particular at different height positions, especially far below the bottom area that the local temperature is lowered and the temperature profile in the width and / or in the height is made uniform.

According to the invention, the respective dividing wall further above can have at least one further coupling passage, which is located further inwardly closer to the middle of the heating channels than the outer circular flow path and is arranged to form an internal inert intermediate layer between the gas and air volume flows (combustion-technically or intermeshing). This allows a homogeneous temperature profile even at higher altitude positions.

It has been found that it is advantageous for the flow conditions that at least one additional exhaust gas recirculation passage (for recirculated exhaust gas flow through the binder wall back into the upflow channel) is located at a height position between the step air inlets and the bottom gas inlets of the heating channel , According to the invention, an inert separating layer can be formed by internally introducing internally reused inert exhaust gas, with a heat-insulating function, with the effect of a delayed, later mixing. In particular, a separating laminar layer can be formed, which prevents cross-mixing or at least slightly further upwards to a higher height position.

In this case, the invention is also based on the knowledge that the exhaust gas can also be performed in an average height position of the respective heating channel, at a lower pressure difference than at the upper and lower end, in terms of one with respect to the outermost Abgasrezirkulations-passages on internal bypass. The further inside, enclosed by the outer circuit bypass or circulating current affects the outer circuit current is not or not noticeable, especially due to the lower pressure difference. However, an influence on the heat transfer or the local temperature can be effectively performed.

In particular, it has been found that even with one or more inner Kreisstrompfaden no risk exists to short-circuit the outer circuit current or to reduce too much in the flow. A short circuit with the outer circuit current or between individual passages can be effectively avoided, in particular, by adapting a spacing between the passages and / or the diameter ratios to the pressure conditions in the respective furnace. Also, a risk that a circular current is formed in the opposite direction, can be controlled, in particular by a flow pulse of the gases admitted is used.

According to one embodiment, the respective partition wall has at least one further coupling lower and / or upper exhaust gas recirculation passage, which is arranged in a central height position closer to the center of the heating channels than the outer circular flow and is adapted for an additional inner bypass circular flow (additional recirculation ) up or down to form a (inertially or intermeshingly) inner inert intermediate layer between the gas and air flow streams on an additional inner bypass loop current path, the inner inert intermediate layer being preferably circumscribed by the outer circular current path.

According to an embodiment, the respective partition wall has a plurality of further coupling exhaust gas recirculation passages which are arranged above and below at least one air stage in the partition wall and are arranged for at least two additional bypass circular currents further inwardly closer to the center of the height of the heating cables than the external one Circulating flow around one or more of the air stages to form one or more inner combustion intermediate air layers on an additional inner bypass loop current path, wherein the respective inner inert intermediate layer is preferably circumscribed by the outer circular current path , This allows a stepped influence on the flow and temperature profile in different height positions, independent of stepped air ducts.

Cross-mixing of recirculated exhaust gases with newly introduced gases can be prevented or at least delayed according to the invention, in particular thanks to predominantly laminar flow conditions in at least one inert intermediate layer. The delaying of the cross-mixing can be done more or less effectively depending on the flow conditions, but in particular at least in such a way that cross-mixing takes place at the earliest above that of a NOx-forming zone. The energetically and economically advantageous concept of the circular current flow can advantageously continue to be fully utilized become, if a very high flame temperature prevails, thus with strong gas heating.

According to one embodiment, the lower and optionally also the upper exhaust gas recirculation passages are formed in the height direction over at least 2 to 5, in particular over at least 3 to 4 wall layers, and / or over a maximum of 8 to 10 wall layers. This provides a good compromise between sufficient structural stability and adequate flow resistance of the recirculated gas. According to one embodiment, the respective lower / lowest exhaust gas recirculation passage extends over a plurality of wall layers or refractory layers in the height direction, in particular over at least 2 to 5 wall layers. This also allows for an adequate flow profile. Also can be done easily integration into an existing design.

According to one embodiment, the inner inert intermediate layer is in x Direction more centrally located than the flow paths of the inflowing gases and further in the center or in a more central height position than the outer circular current path. This favors the stepped influence in each relevant height position.

In one embodiment, the exhaust gas recirculation passages are in the region of the central width (FIG. x ) of the heating channel, in particular in a x Distance to the center longitudinal axis of less than 30 or 20 or 10% of the width of the heating channel. This results in advantages explained above with regard to the inert intermediate layer.

In one embodiment, the respective lower exhaust gas recirculation passage is disposed between the respective coke oven gas inlet and the respective combustion air and / or mixed gas inlet. This allows the previously explained influence on the temperature and flow profile, in particular in the bottom area, in particular a separation of the individual gas streams.

According to one embodiment, the respective coke oven gas inlet is closer than the third width of the heating train ( x Distance between opposing rotor walls) arranged to the rotor wall, in particular at an x-distance of 10 to 350mm, in particular less than 300mm to an inner surface of the rotor wall, wherein the respective lower exhaust gas recirculation passage closer than the third width of the Heizzuges to the center or is arranged toward the central longitudinal axis of the heating train, in particular in one x Distance from 30 to 300mm. This provides effective separation of the gas streams. The flow paths may be parallel without or before cross-mixing occurs.

According to one exemplary embodiment, the respective combustion air inlet and / or mixed gas inlet is closer than the third width of the heating cable (FIG. x- Distance between opposing rotor walls) arranged to the rotor wall, and the respective lower exhaust gas recirculation passage is arranged closer than the third width of the heating cable to the center of the heating cable, in particular in a x Distance from 30 to 300mm. This provides effective separation of the gas streams. The flow paths may be parallel without or before cross-mixing occurs.

It has been shown, in particular in the context of flow tests, that a displacement of the lower exhaust gas recirculation passages closer to the heating cable center makes it possible to separate incoming gases and to reduce cross-mixing. As a result, a targeted influence on the temperature distribution can be taken, in particular in selected height positions. It has been shown that this results in a comparatively low, homogeneous combustion temperature T2 especially in the lower region of the furnace chamber, with a positive effect on the NOx emission.

According to a variant, the respective coke oven gas inlet is arranged closer to the corresponding rotor wall than the respective lower exhaust gas recirculation passage, in particular with its central longitudinal axis at a distance of 10 to 350 mm, in particular less than 300 mm, to an inner surface of the rotor wall. This can also provide design benefits.

According to one exemplary embodiment, at least one further lower exhaust gas recirculation passage or at least one further pair of lower exhaust gas recirculation passages is provided per twin heating train, in particular in at least one further height position above the (first) lower coupling passage, in particular below at least one step air inlet. This allows targeted influence on the temperature and flow profile in selected height positions.

According to one embodiment, up to five further lower exhaust gas recirculation passages or up to five pairs of lower exhaust gas recirculation passages are provided per twin heating train between two stage air inlets. This provides a particularly great flexibility in influencing the respective height position.

According to one embodiment, at least two further pairs of lower exhaust gas recirculation passages in at least two further height positions are above each twin heater train the lowest pair of passages provided, in particular three to seven pairs of lower exhaust gas recirculation passages in three to seven other height positions. This provides a great variability with up to seven internal circulating currents.

According to one embodiment, up to ten further lower exhaust gas recirculation passages or up to ten pairs of lower exhaust gas recirculation passages are disposed in further height positions below the stage air inlets per twin heater train. This allows a distribution of the recirculated gas such that the circular flow can form homogeneously and the gases can gradually mix with each other in the respective height position. A higher number of passages also opens up the option of geometrically adjusting the passages to the desired flow state without too narrow boundary conditions.

The term "staged air" is used here synonymously with the term "staged gas". A stepped air duct can therefore also lead gas unequal to air.

According to one exemplary embodiment, at least one further lower exhaust gas recirculation passage or at least one further pair of lower exhaust gas recirculation passages is arranged in at least one further height position between at least two stage air inlets per twin heating cable. This allows optimization by combining circular flow paths of recirculated gas and inlet paths of step gas.

According to one embodiment, at least one further lower exhaust gas recirculation passage or at least one further pair of lower exhaust gas recirculation passages is arranged both below and above the or each stage air inlets for each twin heater train. This provides particularly high variability.

According to one embodiment, at least one further lower exhaust gas recirculation passage or at least one further pair of lower exhaust gas recirculation passages is arranged in each at least one further height position above or from all the stepped air inlets. This also allows for an inner circuit current (path) decoupled from stepped-in gas.

According to one embodiment, up to five further upper exhaust gas recirculation passages or up to five further pairs of upper exhaust gas recirculation passages are disposed above the or each stage air inlets for each twin heater train. This provides particularly high variability.

By the measures described above, an increased residence time and a more complete burnout can be ensured, in particular with a reduced CO content, and also a higher and in the vertical height direction homogeneous heat input into the furnace chamber can be achieved. In particular, it has been found that with an exhaust gas recirculation of more than 50% it can be ensured that the combustible gas components burn completely to exhaust gas. As a result, the energy content of the medium can be better utilized, in particular continuously over the course of time. As a result, the CO fraction of usually 200 to 400 ppm in the exhaust gas can be further reduced.

If the exhaust gas recirculation passages are arranged above all of the step gas inlets, a portion of the hot exhaust gas can already be conducted into the downwardly flowing heating channel before the reversal point, which has positive effects on the temperature control, in particular also in the gas collection space above the charge. Here usually 800 to 820 ° C are not to be exceeded (soot formation, chemical quality of the raw gas). By further down recirculated exhaust gas and the temperature of the respective furnace chamber can be lowered.

The exhaust gas recirculation passages may each be provided in pairs or individually, that is, even if the number is odd, e.g. three or five more exhaust gas recirculation passages.

It has been found that, depending on the design of the coke oven device, a number between two and ten further flue gas recirculation passages is advantageous.

According to one embodiment, at least two intermediate layers are provided between the individual passages. This also provides good stability. Such stabilization of the heater wall assembly consisting of runner and binder wall is advantageous in terms of stability against coal driving pressures (maximum at about 75% of the cooking cycle). Coke ovens are usually constructed in layers, with layer heights including joints between 100 and 160mm, in particular about 120 to 130mm. The Baulehre for coke ovens teaches a combination of all possible stones of a heating wall via a tongue and groove connection, or by means of tongue and groove curvature. If a large passage cross-sectional area over several layers is desired, the heating wall assembly is weakened and there is a risk of deformation and outgassing of the furnace chamber due to widening joints. This can disadvantageously lead to CO formation due to insufficient existing amounts of combustion air in the heating channel. Therefore, high stability in a lateral (horizontal) direction is very important.

Also in the vertical direction, a bias of the heating wall is desired to protect the Heizwandverbund from vertical deflection. Therefore, a tongue and groove connection is preferred on the upper and lower sides of the stones. The vertical bias of the heating wall is carried out in particular over a sufficiently large ceiling weight.

Further large loading forces on the wall composite occur, for example, in the horizontal expression of the coke charge at the end of the cooking cycle by passing through the chamber steel punch and must be considered by a sufficiently large bias of Heizverbond in lateral and vertical directions. Additional passages, especially those with comparatively large cross-sectional areas, therefore require sophisticated considerations for the stability and longevity of a furnace.

According to a variant, the recirculation passages are arranged as follows: in each case a wall layer with a recirculation passage and above it a composite-stabilizing refractory material layer without passage, always alternating to e.g. Max. ten passages; or in each case one wall layer with a recirculation passage and above it two composite-stabilizing refractory material layers without passage and then a wall layer with a recirculation passage and above this one or two composite-stabilizing refractory material layers without passage. This provides good stability. The passages are comparatively small, but can be well integrated into the design of the furnace.

According to one exemplary embodiment, at least one in particular centrally arranged step air channel is formed in the partition wall with at least one step air inlet, in particular with at least one step air inlet above at least one recirculation passage. This opens up further possibilities of influencing the flow and temperature profile.

According to one embodiment, at least two in particular arranged parallel stepped air passages, which unite above the upper / top exhaust gas recirculation passage and open into a top step air inlet above all exhaust gas recirculation passages in the flamed heating channel in the (respective) partition. This allows e.g. also an optimization of the temperature and flow profiles by means of step-initiated gas at different width positions or (x) -positions. In this case, the unified passage can be easily adjusted from the top of the ceiling by adjusting organ or slider.

According to one exemplary embodiment, at least two, in particular, parallel, stepped air passages are formed in at least one of the partitions, which open into the flamed heating duct above the upper / uppermost exhaust gas recirculation passage in two upper stage air inlets above all the exhaust gas recirculation passages. As a result, the stepped introduced gas can be homogeneously over the width ( x Direction) are introduced into the heating channel.

The redundant design of the stepped air ducts, either with a separate inlet or with a common inlet, provides the advantage that the circulating current can be moved as far as desired into the center, in particular in the lower region of the heating channel, and thus can be very effectively decoupled from the gases admitted. This also constructive advantages may arise, including cost advantages in the construction of the device, or advantages for the operation. The stepped air ducts can also be laid to the outside, so that an inert exhaust gas flow can be formed as centrically as possible (at least more centrically than the other gases) by means of recirculated gases. Also, an advantageous secondary heat distribution can be achieved. Last but not least there are constructive advantages.

According to an exemplary embodiment, the respective lower / lowermost exhaust gas recirculation passage is arranged at a distance of at least 50 mm above the lower region or above the bottom of the heating channel. In this way, a good fluidic effect can be achieved, in particular in coordination with the arrangement of the inlets. In particular, a lower edge of the lowest Rezirklationsdurchlasses is located in the range 0 to 150 mm above the burner levels, above a stabilizing separating layer with a height of about 120 to 130mm, about a further passage with a minimum height of e.g. 120mm, whereby this change between passage and separating layer can extend up to a height of 800mm.

According to one embodiment, the coke oven gas inlet or the corresponding throttle cable (nozzle or tube) is arranged at a distance from the central longitudinal axis of at least 50% of the width of the heating channel. This spacing provides effective decoupling from the centrically located flow paths of the recirculation gases.

According to a variant, the grading is provided only in the ascending heating channel.

According to a variant, at least three additional coupling exhaust gas recirculation passages are provided, wherein at least two inner additional circular flows are formed, wherein above and below a gas stage (outlet a stepped air channel) in each case an exhaust gas recirculation passage is provided. This allows for an effective combination of measures.

According to one embodiment, the combustion air inlet and / or mixed gas inlet and / or coke oven gas inlet are at an angle of 0 ° with respect to the central longitudinal axis of the heating channel (or with respect to a normal to the ground or with respect to the vertical) or at an angle smaller than 30 °, in particular smaller than 20 ° or smaller than 10 ° with respect to the vertical ( z ), in particular all inlets are inclined or aligned in the same direction. This orientation, which is oriented vertically as far as possible, allows a centrally arranged flame, which provides advantages in terms of temperature distribution. As a result, the exhaust gas volume flows centric and nearly perpendicular to the top, ie in the normal direction in the vertical height direction z flow in the heating channel, and the new, introduced gases can form a gas carpet for foreclosure. The volume flows do not bounce against the walls, in contrast to a steeply inclined orientation. As a result, the combustion can be directed to the Heizkanalzentrum, so not to the outer surfaces, whereby moderate temperatures can be adjusted. Local temperature peaks can be effectively avoided. It has been found that the respective inflow pulse can be used particularly advantageously for additional intake of flue gas from the unflamed heating channel or for a more targeted mixing of the gases. The respective inflow pulse can be delivered to the other gases, so does not dissipate on the walls. In contrast, the inlets are usually aligned obliquely in previous ovens in a large angle of inclination of about 30 °. It has been found that the Einströmimpuls of the respective gas are not used particularly effectively in this orientation, in particular not for sucking flue gas from the unflamed Heizkanal. The alignment according to the invention enables particularly high recirculation rates.

According to one exemplary embodiment, the respective combustion air inlet and / or the respective mixed gas inlet and / or the respective coke oven gas inlet have a cross-sectional area of at most 0.06 m ² , in particular also at furnace chamber heights above 6 m. At this upper limit, it can be ensured that the admitted gas flows into the heating channel with a certain minimum pulse or a certain minimum speed, so that the flow conditions in the heating channel can be effectively influenced by means of the inlets. By such a comparatively small cross-sectional area, a high injector effect can be achieved. In particular, the gases can be introduced in such a way that the circulating flow rate or the proportion of the recirculated gas is increased. By such reduced or small cross-sections of the entry pulse of the media can also be increased so that the rate of recirculated exhaust gas can be increased, in particular from about 30 to 45% to about 50 to 80% in Koksofengasbeheizung. It can be set a high flow rate, with the effect that increases the volume flow of sucked or entrained exhaust gas. In particular, high inflow speeds in the heating cable of greater than 2m / s can be realized. Also, a stable flame contour can be ensured, which favors a delayed Ausbrandcharakteristik.

According to one exemplary embodiment, the cross-sectional area of the respective lower and / or upper exhaust gas recirculation passage is greater than 0.005 m ² , in particular greater than 0.01 m ² . This allows a comparatively weak flow pulse of the recirculated exhaust gas, with the effect that the flow pulse of the newly admitted gas acts more strongly. With a comparatively small newly introduced volume flow, a large effect can be achieved thereby, and a high cycle flow rate can be selected.

According to one embodiment, the cross-sectional area of the respective lower exhaust gas recirculation passage has a rectangular, in particular in the width direction ( x ), transversely to the Ausdrückrichtung, elongated geometry. This allows easy integration into the walls, with the option of resizing with minimal design effort. Likewise, the cross-sectional area of the respective upper exhaust gas recirculation passage can be rectangular, in particular in the width direction ( x ), transverse to the ejection direction, elongate geometry or have a square geometry.

The respective inlets and / or the respective passages can be the same size, or be adapted specifically for each height position.

According to one exemplary embodiment, the respective exhaust gas recirculation passage has at least one rounded flow edge and / or convex curvature, in particular with a radius of at least one quarter wall layer (corresponding to degrees or millimeters) or at least 30 °, in particular one inwards with respect to the respective circular flow path lying rounded flow edge or convex curvature. This facilitates the circulating current, in particular even with only slight pressure differences. At the same time, an advantageous flow profile can be ensured in the upward flowed through heating channel.

According to one exemplary embodiment, the respective exhaust gas recirculation passage has at least one sharp flow edge and / or concave curvature, in particular with a radius of at most one or two wall layers (corresponding in degrees or millimeters), in particular a sharp flow edge lying outside with respect to the respective circular flow path or concave curvature. This can ensure that the flow flows on an optimal flow path. Gas guidance contours can be provided by means of the passages or in the passages.

According to one exemplary embodiment, the respective exhaust gas recirculation passage has at least one bypass flow contour with at least one radius and at least one sharp flow edge (or tear-off edge). This combined contour provides a particularly good aerodynamic effect and has the advantage that an additional inner circular flow can already form at very low differential pressures. The respective radius can be formed in particular over an angle of 30 to 60 °. Such flow optimization can make the arrangement of the passages more flexible, especially since even in comparatively high heating channels only very small pressure differences in the range of a few pascals (Pa) can be present. By means of the edges a Strömungshindemis can be created in the passage, with the effect that the flow is forwarded only back into the respectively upwardly flowed through heating channel.

According to one exemplary embodiment, the lower exhaust gas recirculation passages are arranged offset one above the other on both sides of a stepped air duct running in the partition wall, in particular in conjunction with a stabilizing web in the partition wall. As a result, even in a wider latitude range ( x ) Influence on the flow profile. With respect to the horizontal, an offset of between 10 and 200 mm may be advantageous, in particular for the purpose of improving the cooling effect.

According to one embodiment, below the exhaust gas recirculation passages, in particular in a central structure above a regenerator of the coke oven device, at least one transfer passage is arranged for introducing recirculated exhaust gas at the bottom of the respective heating passage at a position between the mixed gas inlet and the combustion air inlet arranged. These transfer passages have a larger flow path and are channel-like (round or rectangular), and may be provided in combination with the above-described bypass openings (heating differential).

According to one exemplary embodiment, at least one of the inlets in the lower region, in particular the coke oven gas inlet, comprises an inlet nozzle and opens into the heating channel at a height position of 0.0 to 0.45 m, in particular 0.05 to 0.25 m, above the bottom of the heating channel. It has been found that such a distance from the ground has a positive effect on the flow profile in the floor area. This embodiment of the nozzle can be referred to as a gas classification, and can be advantageously combined with the other measures described here. A nozzle pipe arranged at the bottom of the heating channel preferably ends approximately 0.25 m high above the channel bottom (burner level) and is preferably made of refractory material. From this pipe, the coke oven gas flows in a height position of about 0.25m and mixes with the incoming air at the bottom.

An inlet nozzle for volume flow calibration can be arranged in head-heated furnaces (= side burner ovens) within this nozzle tube, preferably at the bottom thereof at the level of the channel bottom / burner level. A height position of the nozzle tube smaller than 500 mm, or preferably smaller than 350 or 300 mm, can protect the nozzle disposed therein also from the flow cross-section reducing carbon or soot caking and from high temperatures, and a power loss can be prevented. For underburner furnaces, the nozzle is located below the burner level in the battery cellar, which operates under atmospheric conditions (not endangered by high temperatures). The nozzle tube protrudes in both types of furnaces 0.05 to 0.5m, preferably 0.25m in the heating channel, so that the gas is admitted at Unterbrenneröfen at the same height position as in side burners.

According to one embodiment, the inlet nozzle is oriented orthogonally to the bottom of the heating channel, in particular perpendicular. Preferably, the other inlets are aligned at least approximately orthogonal or vertical.

The above object is also achieved by a method for operating a coke oven device for producing coke by coking coal or coal mixtures with optimized minimized NOx emission by internal thermal energy balance means of coke own gases by primary measures internally to the coke oven apparatus, in particular for operating a previously described Koksofenvorrichtung, wherein in a respective twin heating with a flamed Heizkanal and a flue gas or exhaust gas heating channel, in particular both at the upper and at the lower end of the heating channel, around a partition wall by means of at least one coupling Passage, in particular by means of upper and lower coupling passages through the partition an internal exhaust gas recirculation is set on an outer Kreisstrompfad around the partition around, being introduced in the lower region at the bottom of the respective Zwinsheizs coke oven gas and / or combustion air and / or mixed gas, ie at least a gas from the following group: coke oven gas, combustion air, mixed gas; wherein the admission of at least one of the admitted gases in relation to the width ( x ) of the heating channel is carried out in such an eccentric manner in the heating channel, that the exhaust gas recirculation on one / the circular current path or at least one centric flow path in each case centric (that is, closer to the central longitudinal axis in the xy plane) than the corresponding inlet gas is guided, in particular bounded or flows around both sides of admitted gases, in particular in a recirculation in full circle. This provides the aforementioned advantages. In this case, a decoupling of the exhaust gas recirculation can be realized by means of at least one of the admitted gases fluidically and thermally.

By introducing at least one recirculated partial exhaust gas volume flow between the heating gas volume flow and at least one of the air flow volume flows into the channel, in particular in the bottom region of the upward-heated heating channel, the recirculated partial gas volume flow can be passed on and used as an inert intermediate layer in such a way that the inert intermediate layer contains the reactants gas and Air in the lower part of the heating channel initially separated (combustion technology decoupling) and in the further flow in the vertical direction above causes a delayed Ausbrandcharakteristik. This can cause a NOx-reducing effect.

According to one embodiment, at least one heat-insulating intermediate layer of a partial volume flow of exhaust gas / flue gas is formed from the descending heating channel in a plurality of twin heating ducts each with pairwise heating channels in each case in a partition wall between the heating ducts.

According to one embodiment, the admission of all admitted gases in relation to the width ( x ) of the heating channel more eccentric than the exhaust gas recirculation. This provides a particularly strong effect, in particular regardless of the mode of operation of the furnace.

According to one embodiment, at least one additional inner circular flow is set more centric than the admitted gases and further inwardly than the outer circular flow path and bounded by the outer circular flow path, in particular via at least one pair of additional up and down passages. It has been found that a further inside circular flow provided on the inside can already be formed when there is a pressure difference in the region of a few pascal. The pressure difference can be well below 1 mbar, in particular in the range of less than 10 or 5 pascals (Pa), for example 2 to 4 Pa, and yet the additional circulating current can be formed.

According to one embodiment, the proportion of the exhaust gas recirculated internally on the circular flow path or yarns is adjusted to more than 50%, in particular more than 70%, in particular 80%, during high-temperature gas heating or mixed gas heating. In contrast, the proportion of recirculated exhaust gas was previously at a maximum of 25 to 45% for strong gas heating or a maximum of 10 to 20% mixed gas heating. The high recirculation rate can be achieved through optimized gas routing and enables an energy-efficient process with minimized emissions.

According to one embodiment, the process for high gas heating is performed by using substantially coke oven gas; or wherein the process for mixed gas heating is performed by substantially using a mixture of blast furnace gas, coke oven gas, and optionally also converter gas; or wherein the process is carried out with natural gas as at least partial replacement of coke oven gas. It has been found that the flow concept according to the invention can be implemented in any of these operating modes.

Mixed gas is usually composed of two or three gases or gas mixtures: blast furnace gas (to a large extent), coke oven gas (too low a proportion), and optionally also converter gas. Usually, a coke oven (in particular a composite oven) is heated with strong gas only about 5% of the operating time in the year, at a significantly higher flame temperature above 2,000 ° C (high calorific value of the strong gas or coke oven gas). For mixed gas heating (blast furnace gas), however, the flame temperature is only in the range of about 1,700 ° C, for example. However, there are also ovens that are not operated in combination, and must be operated with 100% coke oven gas or gas. According to the invention, it has been shown that a comparably low NOx emission can be realized for both high and mixed gas heating, despite the very different flame temperature. This provides the kiln operator with maximum flexibility in the operation of his kilns, more or less independently of any predefined emissions regulations, in terms of time or calendar days. In particular, the furnace operator can safely choose a mode of operation for high-temperature gas heating.

As strong gas, purified coke oven gas with lower calorific values between 17,000 and 19,000 kJ / Nm3 is used, especially in downstream plant components. Strong gas usually consists of CO, H2, CH4, O2, N2, CO2 and higher hydrocarbons.

According to the invention, the circulating flow rate of the recirculated exhaust gas can be increased from previously about 30 to 45% to over 50% in the case of strong gas heating, and likewise to more than 50% in the case of mixed gas heating of previously about 15 to 25%. This allows a very effective cooling of the flame temperature in the upward flowing through the heating channel with comparatively cold exhaust gas. In particular, a cooling effect in the range of at least 5 to 60 ° C can be realized, whereby a minimization of thermally formed nitrogen oxides can be achieved. Apart from that, a uniform coke quality can be achieved in particular thanks to a very homogeneous heat flow, and thanks to lower temperature gradient, a thermal load on the chamber walls can be minimized. The furnace may be operated at lower heating temperatures, with at least approximately the same rate of coking as with ovens previously operated at higher temperatures with higher NOx emissions.

In this case, natural gas can also be fed in via the inlet for coke-oven gas, in particular provided as LNG (liquefied natural gas). Depending on the location / source, natural gas consists of 90 to 100% methane (CH4) and marginally higher hydrocarbons. Due to the low flame temperature of methane, methane is a preferred substitute for coke oven gas (less thermal NOx is formed). Methane / natural gas is more expensive. In addition, the own would even produced in the factory, purified coke oven gas can not find a buyer. Depending on the mode of operation, coke oven gas can be at least partially replaced by natural gas. The effects of the present invention can also be achieved using natural gas.

According to one embodiment, a substoichiometric combustion ratio of <0.9 is set, in particular a combustion ratio in the range of 0.5 to 0.8, in particular 0.7, in particular in the bottom region in the burner level at the bottom of the respective heating channel. The smaller the excess air (lambda) is set below the first combustion stage, the weaker the combustion or heat transfer in the lower region of the heating cable can be set. It has been shown that with air numbers in the bottom area of the heating channels smaller than 0.9, in particular in the range 0.5 to 0.8, the required limit values for NOx emissions can be met with a good safety factor. Regardless of this, the air ratio in the range from 1.2 to 1.3 can be set in the header area.

The combustion ratio may be determined by the supply of the total amount of air from one of e.g. 10 to 25 twin heating panels existing heating wall to be controlled in the air valves in front of the entire battery. For this, e.g. Sheets are placed as a resistance in the inlet cross-section of the respective valve, e.g. To obtain a reduction in the amount of air sucked and thus the so-called air ratio of the entire heating wall. In addition, regulating valves for further influencing the total quantity or the direction of partial quantities can be provided in the air valves, which partial quantities each flow into individual regenerator segments. For example, a first regenerator preheats the respective gas and air of the subsurface subsets, and a second regenerator reheats subsets for stage air.

According to one embodiment, by means of the recirculated exhaust gas, a preferably laminar intermediate layer between introduced gas and a stepped air channel or gas from the stepped air channel is formed, in particular in a height range of 5 to 75%, preferably 15 to 50% of the height of the heating channel, in particular over a height section of 0.25 to 4m. This can facilitate separation of the gas streams.

According to one embodiment, by means of the introduced gas, an insulating and mixing-delaying guest carpet is formed between the respective rotor wall and the circular current path (s). The laminar flow or intermediate layer may be characterized in particular by Reynolds numbers less than 2320.

According to one embodiment, the proportion of introduced gas quantities between a first stage, in particular at the bottom through the combustion air and mixed gas inlet (bottom stage) and a second stage (one or more binder wall stages) to 50:50 or even smaller proportion of the first Level set. By means of a higher proportion of recirculated gas, it is optionally possible to lower the proportion of the gas introduced at the bottom in the first stage. This allows further variations in influencing the airfoil, especially in the floor area.

According to one embodiment, the ratio of the volumetric flows introduced into the heating channels is set as follows: <30% through the combustion air inlet, <30% through the mixed gas inlet, and> 40% through the recirculation passages and optionally at least one staged air inlet , According to one embodiment, the in the furnace chamber at the combustion air inlet and at Mixed gas inlet introduced volumetric flow adjusted to between 45 and 55% of the volume flow introduced through the recirculation passages and optionally the at least one stage air inlet. This also allows for a more effective influence on different height positions. The process is carried out in particular with Starkgasbeheizung. Preferably, the process is carried out with Starzgasbeheizung with leaner rich gas with lowered lower heating value in Starkgasbeheizungsmodus by using as gas a gas with a lower calorific value in the range of 14000 to max. 17000 kJ / Nm3 is provided. Thereby, the flame temperature in connection with the measures described above can be considerably reduced, in particular by a difference of 50 to 300K.

According to the invention, the aforementioned object is also achieved by a logic unit or control device configured to carry out a method described above, wherein the volume flows introduced into the heating channels are set according to the above-described conditions, and / or the flow direction in the heating cables is cyclically changed, especially every 15 to 25min. This allows a very homogeneous temperature profile can be achieved even with frequent switching. The switching time is e.g. in the range of 1 to 2min.

The aforementioned object is also achieved according to the invention by using at least one partition wall with at least one further inwardly in the width direction ( x ) Centric than at least one gas inlet, in particular centric than all gas inlets positioned exhaust gas recirculation passage in a twin heating of a coke oven device, in particular in a coke oven device described above. This results in the aforementioned advantages.

The aforementioned object is also achieved according to the invention by using at least one partition wall with at least one further inwardly in the width direction ( x ) centrically positioned as gas inlets exhaust gas recirculation passage exclusively in the pointing to the coke side of a coke oven device half of the twin heating of the coke oven device, in particular in a coke oven device described above. This results in the aforementioned advantages.

The aforementioned object is also achieved according to the invention by using at least one partition wall with at least two, in particular parallel, arranged stepped air ducts, which unite above an upper / upper exhaust gas recirculation passage and in a top step air inlet above all exhaust gas recirculation passages in a flamed heating channel lead; and / or by using at least one partition wall with at least two, in particular parallel, stepped air ducts which open above an upper / upper exhaust gas recirculation passage in two upper stage air inlets above all exhaust gas recirculation passages into the flamed heating duct, in particular in a previously described one Koksofenvorrichtung. This provides high variability in terms of individual optimization measures.

It has been found that the construction effort can be minimized by this structure. The coke-side half becomes hotter in many operating conditions than the carbon-side half, so that it may be sufficient to implement the measures described here in the coke-side half, ie at e.g. 6 to 25, in particular in a maximum of 20 in the ejection direction further back arranged twin pairs, ie per oven chamber in about 6 to 25, in particular in a maximum of 20 partitions.

The aforementioned object is also achieved according to the invention by using a previously described coke oven device for coking coal or a coal mixture comprising at least one additive from the following group: petroleum coke, oil, bitumen types e.g. in the form of scrap tires, coal and coke dust, binding or coking aids, e.g. Molasses, oil residues, cellulosic aggregates, sulphite or sulphate compounds or lye, which mixture may also comprise biomass.

The aforementioned object is also achieved according to the invention by using leaner rich gas with a lowered lower calorific value when operating a coke oven device described above. The lean heavy gas is provided in particular by mixing blast furnace gas and strong gas.

• Hochofengas: 1.92% H2, 59.5% N2, 24.24% CO, 11.96% CO2, 2.37% H2O, mit einem unteren Heizwert von ca. 3349
• Starkgas: 54.98% H2, 0.66% O2, 5.33% N2, 5.75% CO, 1.52% CO2, 26.66% CH4, 2.74% C2H6, 2.37% H2O, mit einem unteren Heizwert von ca. 18422

In particular, as preferred compositions in% by volume (wet state) and lower calorific values (in KJ / m3, dry state, anhydrous) for both blast furnace gas (blast furnace gas) and strong gas (coke-oven gas purified in the secondary recovery), the following values can be cited:

• Blast furnace gas: 1.92% H2, 59.5% N2, 24.24% CO, 11.96% CO2, 2.37% H2O, with a net calorific value of about 3349
• Strong gas: 54.98% H2, 0.66% O2, 5.33% N2, 5.75% CO, 1.52% CO2, 26.66% CH4, 2.74% C2H6, 2.37% H2O, with a net calorific value of approximately 18422

In sum, the percentages given in each case according to the selection of the expert 100% for the respective gas mixture. The components of the respective gas mixture add up to 100 percent. In the trace range, further constituents, in particular higher hydrocarbons, and NH 3 and H 2 S in the respective gas mixture may be contained, in particular in each case below 1.5%. As fluctuation ranges for the individual components a tolerance of + -15% can be called.

• Mischgas: 5.6% H2, 0.1% O2, 55.7% N2, 23.0% CO, 11.2% CO2, 1.9% CH4, 0.2% C2H6, 2.4% H2O, mit einem unteren Heizwert von ca. 4396
• Abgemagertes Starkgas: 45.1% H2, 0.6% O2, 14.4% N2, 8.9% CO, 3.3% CO2, 22.2 CH4, 2.3% C2H6, 2.4% H2O, mit einem unteren Heizwert von ca. 15910

In particular, a mixed gas or a lean heavy gas can be mixed from the blast furnace gas and the purified strong gas, in particular according to the following rounded to the first decimal place components, each with a range of variation for the individual components of + -15% tolerance:

• Mixed gas: 5.6% H2, 0.1% O2, 55.7% N2, 23.0% CO, 11.2% CO2, 1.9% CH4, 0.2% C2H6, 2.4% H2O, with a net calorific value of approximately 4396
• Super lean mass gas: 45.1% H2, 0.6% O2, 14.4% N2, 8.9% CO, 3.3% CO2, 22.2 CH4, 2.3% C2H6, 2.4% H2O, with a net calorific value of approximately 15910

It has been found that the use of lean high gas can already provide a NOX reduction of 30 to 50 ppm (based on 7% O2 in the exhaust), in particular by lowering the local flame temperature to below 2000 ° C. In combination with the previously described measures, the beneficial effect of NOx reduction is further enhanced.

• 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H jeweils in schematischer Darstellung in geschnittenen Seitenansichten und Draufsichten Zwillingsheizzüge bzw. Koksöfen gemäß dem Stand der Technik;
• 2, 3, 4, 5, 6, 7 jeweils in schematischer Darstellung in geschnittenen Seitenansichten in Breiten- und Tiefenrichtung Zwillingsheizzüge gemäß Ausführungsbeispielen;
• 8A, 8B, 8C, 8D, 8E jeweils in schematischer Darstellung in geschnittenen Seitenansichten und in Draufsichten Zwillingsheizzüge bzw. Koksofenvorrichtungen gemäß Ausführungsbeispielen;
• 9 in schematischer Darstellung in geschnittener Seitenansicht einen Querschnitt bzw. eine Querschnittskontur eines Durchlasses in Zwillingsheizzügen gemäß Ausführungsbeispielen;
• 10 ein Verfahrensschaubild bezüglich des Betreibens einer Koksofenvorrichtung gemäß Ausführungsbeispielen; und
• 11, 12 jeweils in schematischer Darstellung in geschnittenen Seitenansichten Zwillingsheizzüge gemäß Ausführungsbeispielen.

Further features and advantages of the invention will become apparent from the description of at least one embodiment with reference to the following figures, as well as from the figures themselves. It shows

• 1A . 1B . 1C . 1D . 1E . 1F . 1G . 1H each in a schematic representation in sectional side views and plan views Zwillingsheizzüge or coke ovens according to the prior art;
• 2 . 3 . 4 . 5 . 6 . 7 each in a schematic representation in sectional side views in the width and depth direction twin heating cables according to embodiments;
• 8A . 8B . 8C . 8D . 8E each in a schematic representation in sectional side views and in plan views Zwillingsheizzüge or Koksofenvorrichtungen according to embodiments;
• 9 in a schematic representation in a sectional side view of a cross section or a cross-sectional contour of a passage in twin Heizzügen according to embodiments;
• 10 a process diagram relating to the operation of a Koksofenvorrichtung according to embodiments; and
• 11 . 12 in each case in a schematic representation in sectional side views Zwillingsheizzüge according to embodiments.

For reference numbers that are not explicitly described with respect to a single figure, reference is made to the other figures. In figures which describe the prior 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 not completely illustrated or not arranged at an exact angle. In figures which describe the present invention, the positions and angular orientations of the individual inlets and passages or flow paths are schematically illustrated (in particular only in individual heating channels), the amounts of the respective distances or the angular orientation being defined in more detail in the description.

The 1A . 1B . 1C . 1D . 1E . 1F . 1G . 1H show a coke oven 1 in the manner of a horizontal chamber oven, with several oven chambers 2 each with coal batch. The oven chambers 2 have a height z2 from eg 6 to 8m. The oven chambers 2 are through runner walls 3 foreclosed, each extending in a yz plane. Between two rotor walls 3 form pairs of heating channels 5.1 . 5.2 one twin heating cable each 5 whose inner wall 5.3 delimits the (free of coal) flowed through by gases boiler room of the respective furnace chamber. The heating channels 5.1 . 5.2 are operated alternately as a flamed or exhaust-carrying heating channel, which requires a switching of the flow direction and in a cycle of eg 20min. he follows.

The pairwise heating channels are each by a coupling partition wall (binder wall) 4 separated from each other, in which above and below a coupling passage 4.4 is provided, via which a circular current 9 is realized by recirculated exhaust gas.

Neighboring twin radiators are separated by a partition wall 4a completely sealed off without any passages.

In the partitions 4 . 4a is in each case a stepped air duct 4.1 arranged, which via at least one combustion stage 4.2 or the corresponding inlet or outlet is coupled to the heating channel. The respective combustion stage 4.2 is in a characterizing altitude position z4 arranged. For example, two or three height positions z4 defines in which stage air is admitted.

The respective walls are made of stones, each with a wall layer 3.1 define.

The x Direction marks the width of the oven 1 , the y Direction indicates the depth (or horizontal direction of ejection in a horizontal chamber furnace), and the z Direction marks the vertical (vertical axis). The middle longitudinal axis M of the respective heating channel extends through the center of the respective heating channel arranged centrally in the x and y directions with respect to the inner surfaces / inner walls. The center of each twin heater is not marked. It lies approximately in the center of the respective circularly flowed partition wall, 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 Level, and the term "center" or "center" refers to the height direction ( z ).

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

As temperatures at the coke oven 1 can be called: nozzle stone temperature T1 , (Gas) temperature T2 in each heating channel, and temperature T3 in the oven chamber. In particular, the present invention relates to the most homogeneous possible distribution of the temperature T2 ,

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). The gas flow G4 indicates recirculation exhaust gases, which are returned or circulated. The gas flow G5 indicates gas or air from a respective combustion stage 4.2 . 14:11 , and the gas flow G6 indicates exhaust gases that are discharged from the respective heating channel or heating train.

With reference to the 1D . 1E The usual distances and relative positions of the individual inlets and outlets are described below.

The distance d4 previously known passages 4.4 in the x-direction to each other is comparatively large. The distance d5 coke oven gas inlet 8th to the other inlets 6 . 7 in the x-direction, in particular a distance between the Koksofengas inlet 8th ; G1a and the other gas streams taken in G1 is relatively small. The distance d5 is smaller than the distance d4 , The distance x4 of the respective passage 4.4 to the inner wall of the rotor wall 3 is comparatively small (in particular, a distance of 120 to 140 mm between the rotor wall and the outer edge of the passage was previously observed). The distance x6 . x8 of the inlet 6 . 8th to the rotor wall 3 is comparatively large. The distance x8 is smaller than the distance x6 , The distance x4 is significantly smaller than the distance x6 . x8 ,

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

1G schematically shows a heating differential 5.6 with individual openings 5.61 , via which the gas can be diverted in a head region of the heating channel. The heating differential 5.6 is through an (intermediate) ceiling 5.7 isolated from the respective twin heating system. The heating differential 5.6 is independent of the circulating current 9 ,

On an illustration of the under the burner level 5.4 arranged central structure of the furnace is deliberately omitted, for the sake of clarity. In the middle section, the supply of gases and the regulation of the flow rates can be done.

The 2 . 3 . 4 . 5 . 6 . 7 show the individual measures according to the invention for optimizing the temperature profile in the respective heating channel. In the 8A . 8B . 8C . 8D . 8E Individual measures are further illustrated in detail.

A coke oven device 10 with oven chambers 10.2 , In particular, with horizontal chamber furnace chambers has a plurality of twin Heizzüge 13 each with a flamed heating channel 11 and an exhaust-carrying heating channel 12 out. The heating channels define with their inner wall 11.1 a heating cable for the passage of gases. The individual heating channels are separated by partitions (binder wall) 14 with coupling passages 14.2 and partition walls 14a delimited without passages from each other. In the partitions 14 . 14a is in each case at least one stepped air channel 14.1 with one or more combustion stages 14:11 or inlets or outlets to / from the heating channel. runners walls 15 limit the furnace chambers and heating channels in y -Direction.

Gas can be through several inlets 16 . 17 . 18 flow into the respective heating channel, in particular via a first combustion air inlet 16 , in particular for Koksofengasbeheizung, via another combustion air inlet 17 , in particular for mixed gas heating, and via a coke oven gas inlet 18 or a coke oven gas nozzle. The recessed and recirculated gas flows both centrally and on inner surfaces 14.3 . 15.1 the respective partition or rotor wall through the respective heating channel down or up.

In 2 is primarily one of the measures of the invention illustrated. A circular current 19 is formed by a plurality of circulating currents which flow around each other on several paths. In 2 is an outer circular current path 19.1 shown, which two further arranged inside circular current paths 19.2 . 19.3 bounded and flows around, with the inner circular current paths 19.2 . 19.3 via the corresponding additional exhaust gas recirculation passages 14.2 are defined.

2 shows an arrangement with three Kreisstrompfaden 19.1 . 19.2 . 19.3 , Which is arranged around a stepped at least approximately halfway height position in the heating channel Stufenluftauslass 14:11 run around. From the Stufenluftauslass 14:11 streams step gas G5 , Optionally, a plurality of stages air outlets may be provided, in particular also above the innermost Kreisstrompfades 19.3 ,

The optimization of the flow and heat profile can thereby primarily by means of the recirculated gas G4 take place, both in the ground area and in several height positions above.

3 shows an arrangement with more than three Kreisstrompfaden, wherein the number of lower passages is greater than the number of upper passages. The optimization can be done especially in the ground area primarily by means of recirculated gas G4 without the requirement of stepped admission of tap gas. In the head area of the heating channel is a heating differential 5.6 provided, which is hinzuschaltbar example by means of pusher blocks independently of the respective circulating currents.

4 shows an arrangement with more than three Kreisstrompfaden, the number of lower passages is significantly greater than the number of upper passages. In particular, six lower passages (or pairs of passages) are provided in six different height positions. The lower passages are all under a stepped air outlet 14:11 arranged a centric staged air channel. The six lower passages are provided in pairs adjacent to the stepped air passage, and the upper passages are provided individually and arranged centrally. Above the Stufenluftauslass a single centric lower passage is arranged. In this arrangement, a particularly wide centric two-flow path results from bottom to top, which weitre above is supplemented by step gas and the centrically introduced recirculation gas.

With reference to the 5 . 6 . 7 becomes the cross-sectional area Q14 of the respective coupling passage 14.2 described on the inner surface to the heating channel. The cross-sectional area Q14 from above a stepped air channel 14.1 arranged passages 14.2 is wider or elongated than the cross-sectional area Q14 from the side next to the stepped air duct 14.1 arranged passages 14.2 ,

5 shows an arrangement with compared to 4 several centric Stufenluftauslässen 14:11 and with passages of different cross section: the lower passages are at least partially elongated in z Direction, and the upper passages are elongated in x -Direction. In this variant, the stepped air duct is bordered on both sides by several lower passages, but not in pairs. The number of lower passages on one side is different than the number of passages on the other side. The passages stretched in the z-direction allow an advantageous relative arrangement, in particular very far centric (comparatively small distance d2 ), and especially with optimized flow profile. The comparatively large cross-section Q14 of the passage shown on the right allows a strong flow effect of the introduced gas G1 , especially over a large height section.

In 5 is a distance d2 between an inner wall / edge of the corresponding passage 14.2 and an outer wall / edge of a particular centrally arranged in the heating train stage air channel 14.1 in x Direction to each other. This distance d2 is very small according to the invention, in particular 30 to 100 mm, preferably 50 to 70 mm. Especially with centric arrangement of the stepped air channel 14.1 can the passages 14.2 according to the invention as close as possible in x Direction be positioned next to it.

6 shows an arrangement with two stage air ducts, which open separately in several height positions in the heating channel. All lower passages 14.2 below the uppermost Stufenluftauslasses are arranged centrally, in particular symmetrically with respect to the central longitudinal axis. Above the stage air intakes 14:11 are two more pairs of lower passages (four passages) in a width position ( x ) at least approximately according to the width position of Stufengasauslässe 14:11 arranged. The paired passages can also be arranged at several height positions, also laterally next to each other.

The lower passages may alternatively be made narrower than the upper passages and / or narrower than the uppermost lower passages. The uppermost lower passages may also be provided as individual passages (no pairs) and may be arranged in such a width position that step gas may flow past / along the respective passage and mix with the recirculated gas.

7 shows an arrangement with two stage air ducts, which together in a height position between individual lower passages united 14.2 run centrally into the heating channel, wherein optionally further separate stage air outlets can be provided in the respective stage air channel. The centric stage air inlet 14:11 In particular, it extends over a width which completely overlaps the overlying lower passage. The lower passages are offset from each other in the x-direction by the offset x2 arranged. The offset x2 also provides the advantage of a particularly wide, homogeneous flow (without more heavily flowing core), especially in comparatively wide passages in the x-direction 14.2 , The circulating current can thereby be made even more homogeneous. Optionally, a plurality of upper passages may be provided. Such an offset can also be found in the 6 be shown arrangement provided.

In 7 is an offset x2 in x Direction illustrated. This offset between adjacent passages 14.2 is in particular 50 to 100mm and provides the advantage of a good heat distribution.

With reference to the 8A . 8B . 8C . 8D . 8E The distances and relative positions of the individual inlets and passages according to the invention will be described below in a further exemplary embodiment.

In 8A is schematic (in some heating channels) the arrangement of the inlets 16 . 17 . 18 opposite each other, and in the x-direction spaced from the central longitudinal axis as close to the rotor walls 15 shown. This arrangement can be chosen at each of the heating channels, or even modified.

In 8B is shown that the inlets 16 . 17 . 18 in x Direction farther out than the culverts 14.2 are arranged. The passages are at a distance d14 arranged to each other, which is smaller than the distance d15 the inlets.

In 8C It is shown that the middlemost, centric inflowing step gas G5 further out on both sides of recirculated gas G4 is flowed around, which is farther out, respectively, of admitted gas G1 . G1a . G1b is flowed around. The in 8C illustrated angle a, in particular the coke oven gas inlet 18 concerning, is set too large for better understanding. According to the invention, the angle α be particularly small, in particular converge to zero or 0 °. Depending on the design of the central structure and an angle in the range of 5 to 10 ° can be a rational compromise of additional constructive, plant engineering effort and achieved fluidic effect.

In the 8C shown passages 14.2 or the stepped gas inlet 14:11 can in the arrangement, number and geometry according to the in 2 to 7 varied variants are varied. In the 8C shown individual gas streams G1 . G1a . G4 . G5 let recognize in which way according to the invention a separation of the gas streams or a parallel flow at least over a certain height section can be realized.

The distance d14 the passages 14.2 in x Direction to each other is comparatively small, in particular smaller than 50, 45, 40, 35 or 30 percent of the width ( x ) of the heating channel. The distance d15 coke oven gas inlet 18 to the other inlets 16 . 17 in the x-direction is comparatively large, in particular greater than 70, 75, 80 or 85 percent of the width ( x ) of the heating channel. The distance d15 is significantly larger than the distance d14 , in particular at least 35, 40, 45, 50 or 55 percent larger. The distance x14 of the respective passage 14.2 to the inner wall of the rotor wall 3 is comparatively large, in particular greater than 35, 40 or 45 percent of the width ( x ) of the heating channel (with paired passages). Particularly preferred is the distance x14 at least greater than 40 percent of the width ( x ) of the heating channel, in particular in the bottom area. The distance x16 . x18 of the inlet 6 . 8th to the rotor wall 15 is comparatively small, in particular smaller than 20, 15 or 10 percent of the width ( x ) of the heating channel. The distance x16 . x18 is each smaller than the distance x14 , In particular, the distance x14 at least twice or at least three times the distance x16 . x18 ,

With reference to the 8B to 8E The individual gas flows are described below. The respective gas flow path GP1 indicates inflow paths or flow paths according to the invention for at least one of the gases introduced via the inlets G1 , The respective gas flow path GP4 characterizes inventive flow paths of recirculated exhaust gas / flue gas G4 , and the respective gas flow path GP5 indicates flow paths according to the invention of staggered gas introduced G5 ,

The in 8C . 8E Illustrated inflow angle a, 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 α can analogously for the other inlets 17 . 18 will be realized.

The respective y-position of the individual inlets may in particular be centric.

The distances and relative positions mentioned with respect to the respective inlets and passages may also be reciprocally related to the distances and relative positions of the respective gastric paths / circular flow paths, at least in one section upstream of a subsequent mixing with adjacent gas flows.

In 9 a passage cross section is shown in the yz plane. The recirculated gas G4 flows through the respective lower passage 14.2 coming from above and also flows upwards again. The gas G4 flows around two rounded flow edges 14:21 , and flows at two sharp edges 14:22 past. The partition 14 limits the passage at the top with a convex curvature downwards. This promotes a low flow resistance. The partition 14 also limits the passage below. The circular circulating current, which here has a very narrow radius, can thus flow through the passage without strong turbulences and be redirected upward. Down can have one or more sharp edges 14:22 to limit a flow. This type of flow optimization also makes it possible to achieve a great effect by means of the way in which the new gases are introduced. In particular, the recirculated gases generate G4 no or only slight turbulence, so that the flow profile can be effectively optimized by means of the inlets.

In 10 schematically illustrates that the coke oven device 10 a control unit 20 arranged to control one of the previously described volume flows V (t) , in particular at least the volume flows G1 . G1a . G1b . G4 . G5 . G6 , The control and adjustment of the volume flows makes it possible to influence the flow and temperature profile in the respective heating channel 11 . 12 , Thus, the NOx emissions can be adjusted indirectly via the volume flows.

The 11 . 12 show variants of in 5 shown embodiment. In 11 For example, some of the lower passages disposed above the uppermost stage air outlet are paired with a single, larger, lower, lower passage.

In 12 only two recirculation passages are provided between the lowest step gas opening and the burner level, in particular in a comparatively high height position greater than 500 mm. This makes it possible to dispense with passages further down in the floor area.

The in the 2 to 12 shown positions of the inlets are shown by way of example. Each inlet can be arranged and aligned independently of the other inlets. The embodiments shown can in particular also be varied by varying the arrangement of the lower passages, or by dispensing with individual or all lower passages.

With particular reference to the embodiments of the 5 . 6 . 11 . 12 a variation of the arrangement and size of the passages, in particular the arranged above the uppermost Stufenluftauslasses passages and / or arranged in a height position between individual Stufenluftauslässen passages, in each case by changing to pairwise passages. In this case, it is also possible to dispense with some or all of the passages arranged in the base region, with a displacement of these passages further upwards into a height range above 500 mm. The number of Stufenluftauslässe or the height positions with grading is not limited to the variants shown.

LIST OF REFERENCE NUMBERS

1

Coke oven, in particular horizontal kiln

2

Furnace chamber with coal charge

3

runners wall

3.1

wall location

4

coupling partition or binder wall

4a

partitioning partition without passages

4.1

Channel or stepped air duct in partition

4.2

Combustion stage or inlet or outlet on the stepped air channel from / to the heating channel

4.3

wall surface

4.4

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

5

Twin heating cable (paired arrangement of two vertical heating cables)

5.1

flamed heating channel (vertical heating cable)

5.2

exhaust-carrying heating channel (vertical heating cable)

5.3

inner wall

5.4

Burner level or bottom of a heating channel

5.6

heating differential

5.61

single opening in the heating differential

5.7

(Intermediate) ceiling of a heating channel

6

(first) combustion air inlet, in particular for Koksofengasbeheizung

7

further combustion air inlet or inlet for mixed gas heating

8th

Coke oven gas inlet or coke oven gas nozzle

9

loop current

10

Coke oven device, in particular with horizontal chamber furnace

10.2

furnace chamber

11

flamed heating channel (vertical heating cable)

11.1

inner wall

12

exhaust-carrying heating channel (vertical heating cable)

13

Twin heating cable (paired arrangement of two vertical heating cables)

14

Partition wall or binder wall

14a

partitioning partition without passages

14.1

Channel or stepped air duct in partition

14:11

Combustion stage or stage air inlet or outlet at the stage channel from / to the heating channel

14.2

two heating channels coupling passage

14:21

rounded flow edge

14:22

sharp edge of the stream

14.3

Inner surface of the partition

15

runners wall

15.1

Inner surface of the rotor wall

16

(first) combustion air inlet, in particular for Koksofengasbeheizung

17

further combustion air inlet or inlet for mixed gas heating

18

Coke oven gas inlet or coke oven gas nozzle

19

loop current

19.1

outer circular current path

19.2

(first) inner circular current path

19.3

(further) inner circular current path

20

Logic unit or control device

d2

Distance between an inner wall / edge of the corresponding passage 14.2 and an outer wall / edge of a particular centrally arranged in the heating train stage air channel 14.1 in the x-direction to each other

d4

Distance from previously known passages 4.4 a twin Heizzuges in the x direction to each other

d5

Distance of coke oven gas inlet 8th to further inlets in the x-direction, in particular distance between the Koksofengas inlet 8th ; G1a and the other gas streams taken in G1

d14

Distance between passages according to the invention 14.2 a twin Heizzuges in the x direction to each other

d15

inventive distance of the coke oven gas inlet 16 to further inlets in the x-direction, in particular between G1 and G1a

G1

Heating gas or combustion air

G1a

coke oven gas

G1b

mixed gas

G4

recirculation exhaust

G5

Step gas or staged air from the combustion stage

G6

exhaust

GP1

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

GP4

Flow path of recirculated exhaust gas / flue gas

GP5

Flow path of stepped gas introduced

M

Center longitudinal axis of the respective heating channel

Q14

Cross sectional area of the coupling passage on the inner surface to the heating channel

T1

Nozzle block temperature

T2

(Gas) temperature in the heating cable / heating channel

T3

Temperature in the oven chamber

V (t)

Volume flow of the respective gas stream, e.g. in m3 / h

x

horizontal direction (width or length)

x2

Offset in x-direction

x4

Distance from the known passage 4.4 to the inner wall of the rotor wall 3

x6

Distance from the known inlet 6 to the inner wall of the rotor wall 3

x8

Distance from the known inlet 8th to the inner wall of the rotor wall 3

x14

Distance of the passage according to the invention 14.2 to the rotor wall

x16

Distance of the inlet according to the invention 16 to the rotor wall

x18

Distance of the inlet according to the invention 18 to the rotor wall

y

Depth or horizontal ejection direction

z

vertical direction (vertical axis)

z2

Furnace chamber height

z4

Height position of a respective stage air inlet / outlet

α

Inlet angle for coke oven gas with respect to the z-axis (vertical)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 3443976 C2 [0023]
• DE 3812558 C2
• CN 107033926 A [0024]
• DE 3916728 C1 [0025]
• DE 4006217 A1 [0029]

Cited non-patent literature

• 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]
• A.J. Nowak et al .: CFD model of coupled thermal processes within the coke oven battery .... Computer Assisted Mechanics and Engineering Sciences, 17: 161-172, 2010 [0002]

Claims (15)

A coke oven apparatus (10) for producing coke by coking coal or coal mixtures, the coke oven apparatus being adapted to minimize nitrogen oxide emissions by internal thermal energy equalization by means of coke-oven gases (G1, G4, G5) internally at the coke oven apparatus, with a plurality of twin flues ( 13) in each case with a gas-fired heating channel (11) and an exhaust-carrying downwardly flowed through heating channel (12), which heating channels in pairs by a partition wall (14) delimited from each other and by two opposing rotor walls (15) of a respective furnace chamber (10.2) are sealed, wherein the pairwise heating channels are fluidly coupled by means of an upper coupling passage (14.2) and optionally also by means of a lower coupling passage for internal exhaust gas recirculation (19) on an outer circular current path (19.1) to each other, wherein in the lower part at Bo each of (5.4) of the respective twin heating train is provided with at least one inlet of the following group: coke oven gas inlet (18), combustion air inlet (16), mixed gas inlet (17); characterized in that at least one of the inlets (16, 17, 18) is arranged more eccentrically with respect to the width (x) of the heating channel than at least one of the passages (14.2) and a flow path (G1, G1) arranged more eccentrically than the exhaust gas recirculation (19) G1a). Koksofenvorrichtung after Claim 1 wherein all the inlets (16, 17, 18) are arranged more eccentrically with respect to the width (x) of the heating channel than at least one of the passages (14.2); or wherein at least one of the inlets, in particular all the inlets (16, 17, 18) with respect to the width (x) of the heating channel are arranged eccentric than the lowest passages (14.2) or more eccentric than all the passages. A coke oven apparatus according to any one of the preceding claims, wherein the respective combustion air inlet (16) and / or the respective mixed gas inlet (17) and / or the respective coke oven gas inlet (18) have a cross-sectional area of at most 0.06 m ² ; and / or wherein the cross-sectional area of the respective exhaust gas recirculation passage (14.2) is greater than 0.005 m ² , in particular greater than 0.01 m ² . A coke oven apparatus according to any one of the preceding claims, wherein the combustion air inlet (16) and / or mixed gas inlet (17) and / or coke oven gas inlet (18) are at an angle (a) of 0 ° with respect to the central longitudinal axis of the heating channel or are aligned at an angle less than 30 °, in particular less than 20 ° or less than 10 °; and / or wherein at least one of the inlets, in particular the coke oven gas inlet (18), comprises an inlet nozzle and in a height position of 0.0 to 0.45m, in particular 0.05 to 0.25m above the bottom of the heating channel in the heating channel (11, 12 ) opens. Coke oven device according to one of the preceding claims, wherein the respective partition (14) has at least one further coupling lower and / or upper passage (14.2), which is arranged in a central height position closer to the center of the heating channels than the outer circular current path (19.1) and set up is for forming an inner inert intermediate layer on the centric flow path (GP4); and / or wherein the respective partition wall (14) has at least one further lower and / or upper coupling passage (14.2), which is arranged in a central height position closer to the center of the heating channels than the outer circular flow and is adapted for an additional inner circular flow up or down to form an inner inert intermediate layer on an additional inner circular current path (19.2, 19.3). Coke oven device according to one of the preceding claims, wherein in the partition wall (14) at least one in particular centrally arranged step air channel (14.1) with at least one stage air inlet (14.11) is formed; or wherein at least two, in particular arranged in parallel, stepped air passages (14.1) are formed in the dividing wall (14), which join above the upper / uppermost exhaust gas recirculation passage (14.2) and in a topmost stepped air inlet (14.11) above all exhaust gas recirculation passages (14.11). 14.2) open into the flamed heating channel (11); and / or wherein in at least one of the partitions (14) at least two in particular parallel arranged stepped air channels (14.1) are formed, which above the upper / top exhaust gas recirculation passage (14.2) in two upper stage air inlets (14.11) above all exhaust gas recirculation passages into the flamed heating channel (11). Coke oven device according to one of the preceding claims, wherein the respective exhaust gas recirculation passage (14.2) has at least one rounded flow edge (14.21) and / or convex curvature, in particular with a radius of at least one quarter wall layer or at least 30 °, in particular one inside with respect to the rounded flow edge or convex curvature lying in the respective circular flow path; and / or wherein the respective exhaust gas recirculation passage has at least one sharp flow edge (14.22) and / or concave curvature, in particular with a radius of at most one or two wall layers or 120mm, in particular a sharp flow edge or concave curvature located outside with respect to the respective circular flow path; and / or wherein the respective exhaust gas recirculation passage (14.2) has at least one bypass contour with at least one radius and at least one sharp flow edge. A method for operating a coke oven apparatus (10) for producing coke by coking coal or coal mixtures with optimized minimized nitrogen oxide emissions by internal thermal energy compensation by means of coke own gases (G1, G4, G5) by measures internally on the coke oven apparatus, in particular for operating a coke oven apparatus after one of the preceding claims, wherein in a respective twin heating cable (13) of the coke oven device with a flamed heating channel (11) and an exhaust gas carrying heating channel (12) by means of at least one coupling passage (14.2) through a partition wall (14) an internal exhaust gas recirculation (19) on a external circuit current path (19.1) is set around the baffle, whereby in the lower area at the bottom (5.4) of the respective Zwillingsheizzuges a gas from the following group is introduced at least: coke oven gas (G1a), combustion air (G1), the mixed gas (G1b), characterized by admitting at least one of admitted gases with respect to the width (x) of the heating channel so eccentric in the heating channel, that the exhaust gas recirculation (19) on one / the circular current path (19.1, 19.2, 19.3) or at least one centric flow path (GP4) each centric than the corresponding recessed Gas (G1a, G1, G1b) is guided, in particular bounded on both sides of introduced gases. Method according to the preceding method claim, wherein the admission of all admitted gases with respect to the width (x) of the heating channel takes place more eccentrically than the exhaust gas recirculation. Method according to one of the preceding method claims, wherein at least one additional inner circular flow (19.2, 19.3) is adjusted more centrically than the admitted gases (G1) and further inside than the outer circular flow path (19.1) and bounded by the outer circular current path, in particular via at least one pair of additional ones Passages (14.2) above and below; and / or wherein the proportion of the recirculated on the or the Kreisstrompfaden (19.1, 19.2, 19.3) internally recirculated exhaust gas at Starkgasbeheizung or mixed gas heating at over 50%, in particular over 70%, in particular at 80%; and / or wherein the high gas heating process is performed by using substantially coke oven gas or by using leaner lean gas having a lowered net calorific value, in particular less than 17000kJ / Nm ³ ; or wherein the process for mixed gas heating is performed by substantially using a mixture of blast furnace gas, coke oven gas, and optionally also converter gas; or wherein the process is carried out with natural gas as at least partial replacement of coke oven gas. Method according to one of the preceding method claims, wherein a substoichiometric combustion ratio of <0.9 is set, in particular a combustion ratio in the range of 0.5 to 0.8, in particular 0.7, in particular in the burner level (5.4) at the bottom of the respective heating channel (11, 12). Method according to one of the preceding method claims, wherein by means of the recirculated exhaust gas (G4) an intermediate layer between introduced gas (G1) and a stepped air channel (14.1) or gas (G5) is formed from the stepped air channel, in particular in a height range of 5 to 75% or 15 to 50% of the height of the heating channel or over a height range of 0.25 to 4m; and / or wherein by means of the admitted gas (G1) a Gasteppich between the respective rotor wall (15) and the / the Kreisstrompfaden (19.1, 19.2, 19.3) is formed. Method according to one of the preceding method claims, wherein the proportion of introduced gas quantities between a first stage, in particular at the bottom (5.4) through the combustion air and mixed gas inlet (16, 17), and a second stage (z4) to 50:50 or is set with an even lower proportion of the first stage, in particular with strong gas heating; and / or wherein the ratio of the volumetric flows introduced into the heating channels (11, 12) is set as follows: <30% through the combustion air inlet (16), <30% through the mixed gas inlet (17), and> 40% through the recirculation passages and optionally at least one stage air inlet (14.11), in particular with strong gas heating; and / or wherein the volumetric flow introduced into the furnace chamber at the combustion air inlet and the mixed gas inlet is adjusted to between 45 and 55% of the volumetric flow introduced through the recirculation passages and optionally the at least one stepped air inlet, in particular with high gas heating. Control device (20) configured to carry out a method according to one of the preceding method claims, wherein the volume flows (G1, G4, G5) introduced into the heating channels (11, 12) are selected according to the conditions according to Claim 13 be set. Use of leaned rich gas with lowered lower calorific value for operating a coke oven apparatus according to a method according to any one of the preceding Method claims, in particular in a coke oven device according to one of the preceding device claims.

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