EP3681977A1

EP3681977A1 - Coke oven device with circumflowed circular current path for producing coke and method for operating the coke oven device and control system and use

Info

Publication number: EP3681977A1
Application number: EP18769663.8A
Authority: EP
Inventors: Ronald Kim; Thomas TSCHIRLEY; Rafal Grzegorz Buczynski
Original assignee: ThyssenKrupp AG; ThyssenKrupp Industrial Solutions AG
Current assignee: ThyssenKrupp AG; ThyssenKrupp Industrial Solutions AG
Priority date: 2017-09-15
Filing date: 2018-09-13
Publication date: 2020-07-22
Anticipated expiration: 2038-09-13
Also published as: CN111492038B; WO2019053103A1; EP3681979A1; WO2019053105A1; TW201915152A; EP3681979B1; CN111492038A; CN111436202B; CN111479902A; TWI682027B; CN111436202A; TW201915151A; EP3681977B1; EP3681978A1; PL3681979T3; CN111479902B; EP3681978B1; TWI681049B; TW201915150A; TWI681048B

Abstract

The invention relates to a coke oven device (10) for producing coke by carbonisation of coal with minimised nitrogen oxide emission by means of measures carried out inside the coke oven device, with a plurality of double flues (13) each with a heating channel (11) subjected to flame treatment and a heating channel (12) conducting exhaust gas, said heating channels being isolated by partitions (14) and by stretcher walls (15), the pairs of heating channels being coupled to each other in a flow-conducting manner by means of an upper and a lower coupling passage (14.2) for internal exhaust gas recirculation, on an outer circular current path (19, 19.1), and at least one inlet is provided on the bottom (5.4) of each double flue, selected from the following group: a coke oven gas inlet (18), a combustion air inlet (16), and a mixed gas inlet (17), the respective partition (14) comprising at least one other lower and upper coupling passage (14.2), which are arranged in a more central height position closer to the height centre of the heating channels than the outerlying circular current, and are designed to form an additional inner circular current path (19.2, 19.3). The invention also relates to a method for operating the coke oven device.

Description

Coke oven apparatus with circulating flow path around it for producing coke and method for operating the coke oven apparatus, as well as

Control device and use 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, such as in the United States. 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 must be carried out over a long period of time, especially as 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 over 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 regard, there are numerous efforts to improve the efficiency of coking or environmental friendliness, such as, for example, can be read in the following publication and the technical articles cited therein: 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. This publication deals with the simulation of previously known optimization measures.

As currently permitted or still tolerated emission limits in existing plants can be called: 500mg / Nm ³ , corresponding to about 250ppm at 5% oxygen 02. As future Limits can be mentioned: about 350mg / Nm ³ (about 170ppm at 5% 02) in Europe, or soon probably 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 It is therefore not interesting or feasible for the kiln operator to operate the coke oven in its optimal operating condition. Consequently, it is accepted that NOx emissions remain adversely 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. In horizontal chamber furnaces, coking is carried out in batches. 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 can mean a computational effort of several weeks per calculation, so that also in simulations a workload of several years (for example, over 100 required variations) can 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 Gassammeiraumtemperatur 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 The 1970s also examined in more detail the effects of the circulating current system on NOx emissions.

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 usually back in the flamed heating channel led partial volume flow of the flue gas is in Starkgasbeheizung eg 30 to 45% of the total flue gas volume produced in the upward flow 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. Previous to the mid-1980s was either an air classification (Otto 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 also has, where appropriate, very disadvantageous side effects to be avoided, for example, on the statics of the heating walls, on the flow resistance, or the finally adjusting flow velocities 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) arises, in particular on rotor walls at a height of about 1 m above the burner level, which driving pressure can even lead to widening of joints and thereby undesired bypass flows (in conjunction with coke oven gas transitions and the concomitant CO formation) between individual heating elements and (adjacent) furnace chambers. 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.

For a battery with multiple furnace chambers, e.g. 40 or 60 furnace chambers, the furnace chambers are delimited by rotor walls against gas-carrying 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 partitioned off from one another by so-called binder walls (partitions), which extend in particular orthogonally 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 in this case e.g. in the range of 80 to 120mm. A binder wall thickness is e.g. in the range of 120 to 150mm.

In the present specification, this term is used interchangeably with the term "partition wall", in particular to clarify that a rotor wall and a binder wall / partition can be made in the same construction, namely by each on the narrow side of each other lined up stones. The "rotor wall" of a horizontal chamber furnace can also be used as longitudinal wall arranged in the ejection direction, and the "binder wall" can also be described as arranged transversely to the pressing direction transverse (separating) wall.

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 DE 34 43 976 C2 and DE 38 12 558 C2, in which the question of an optimum cycle flow rate and a reasonable height position for stepped introduction of combustion air is discussed, can be mentioned by way of example, 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.

The publication CN 107033926 A of August 2017 describes an arrangement with twin heating systems with stepped introduction of combustion air and with circular flow openings, which are arranged on both sides laterally from 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 heating rooms (heaters) with internals in the form of permeable honeycomb bodies or honeycomb lattices 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 be referred to here 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 tried, 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 may be mentioned, 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 circuit is described, with the aim of homogeneous heating conditions and low NOx emission even at high furnace chambers.

The publication DE 10 2009 015 270 A1 describes a coking plant with exhaust gas recirculation, wherein single-circuit flow openings are provided for the recirculation of exhaust gas.

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 previously expressed concerns, 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 Heating cables at least one recirculation opening, in particular with Kreisstromführung, in particular to obtain the option to operate the coke oven in power-optimized mode even 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 pairwise heating channels, in particular both at the upper and at the lower end, fluidically by means of an upper coupling passage and by means of a Each of the lower coupling passage is coupled to each other for internal exhaust gas recirculation on an outer circular flow path, wherein at least one inlet of the following group is provided in the lower region at the bottom of the respective Zwwiningsheizzuges: Koksofengas inlet for introducing coke oven gas into the heating channel, combustion air inlet , Mixed gas inlet; wherein the respective partition wall has at least one further lower and upper coupling passage, which are arranged in a central height position closer to the mid-height of the heating channels than the external circular current and are arranged for an additional inner circular current up and down to form an inert intermediate layer on an additional inner circular current path. The redundant design of the circular current paths provides in particular a high variability and a strong effect in different height positions, which is advantageous even with particularly high furnace chambers. The effect extends to both heating channels by the measure for a full-scale, closed circular current is made. As a result, the temperature distribution can be made uniform, especially in the floor area. In particular, it has been shown 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 combustion retardant effect. According to one embodiment, the additional inner circular current path extends over pairs of lower and / or upper passages, which are each arranged in pairs in at least approximately the same height position. This provides a homogeneous temperature distribution in the x-direction over a large width. Optionally, more than two or three passages may be provided in the same height position.

According to one embodiment, at least one further inner circular current path is formed by means of the passages, which is flowed around by at least two outer circular currents on outer Kreisstrompfaden. The multiple redundancy of circulating currents provides a particularly homogeneous temperature distribution and allows great variability.

According to one embodiment, 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) arranged as at least one of the inlets and a centric or centric flow path defined by at least one of the gases admitted via the inlets defined. In particular, at least all lower exhaust gas recirculation passages are more centric than all inlets. This exhaust gas recirculation flow path is arranged more centrically than the corresponding flow paths or inflow paths of the introduced gases. As a result, the heat distribution in the heating channel can be optimized in the first place, in particular evened out. As a result, the respective coke oven gas inlet can be arranged in terms of flow and heat energy with respect to at least one passage or 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.

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 flow" or "Kreisstrompfad" can also be related to a not fully closed, but for example, only about 180 ° or 270 ° in the circulated flow ,

These measures allow, in particular, a combustion-inert and mixture-delaying intermediate layer and a cooling in the bottom 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 to keep a temperature difference over the entire height of the heating channel 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 1 100 ° 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% 02) may be expected. In particular, it can be expected that a level of less than 100ppm NOx (at 5% 02) 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. Within the scope 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 already produces a very hot gas mixture forms 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 found that the air or gas guide according to the invention can be realized not only in twin heating trains, but also in so-called four-pass furnaces or alternative arrangements in which the concept of fluidly coupled heating cables is taken up and multiplied in particular in each case pairwise 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 described optimization measures, at least one combustion air or stepped air inlet for introducing combustion air from a stepped air duct running in the partition wall into the heating duct in at least one combustion stage height position can be provided in the partition wall. 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 also extend, for example, to a height of 1200 mm. 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 that defines a lower inflection point of a circular flow or a flow, especially 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 allows as close as possible relative to the rotor wall a centric recirculation even in a floor 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. The flow path can form or supplement a circular flow.

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 exhaust gas Binder wall back into the upward flowed through heating channel) is arranged in a height position between the stage air inlets and the bottom-side 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 upper exhaust gas recirculation passage, which are arranged in a central height position closer to the height center of the heating channels than the outer circular flow and are adapted for an additional inner bypass circular flow (additional recirculation) up or down to form a (inertially or intermeshingly acting) inner inert intermediate layer between the gas and air flow streams on an additional inner Bypass circular current path, wherein the inner inert intermediate layer is bounded 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 even if a very high flame temperature prevails, ie in the case of 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 an adequate Flow profile. Also can be done easily integration into an existing design.

According to one embodiment, the inner inert intermediate layer is arranged in the x-direction farther inward or centrically than the flow paths of the inflowing gases and further in the middle or in a more central height position than the outer circular current path. This favors the stepped influence in each relevant height position.

According to one embodiment, the exhaust gas recirculation passages are arranged in the region of the central width (x) of the heating channel, in particular at an x-distance from the central 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 arranged closer than the third width (closer than one third of the width) of the heating cable (x-distance between opposite rotor walls) to the rotor wall, in particular at an x-distance of 10 to 350mm, in particular less as 300mm to an inner surface of the rotor wall, wherein the respective lower exhaust gas recirculation passage is arranged closer than the third width of the Heizzuges to the center or to the center longitudinal axis of the Heizzuges, in particular at an x-distance of 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 an exemplary embodiment, the respective combustion air inlet and / or mixed gas inlet is arranged closer to the rotor wall than the third width of the heating cable (x-distance between opposing rotor walls), and the respective lower exhaust gas recirculation passage is closer than the third width of the heating cable to the center of Heizzuges arranged out, in particular at an x-distance of 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 a relatively low, homogeneous combustion temperature T2 can be set thereby, in particular 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 are provided per twin heater train in at least two further height positions above a lowermost pair of passages, in particular three to seven pairs of passages lower exhaust gas recirculation passages in three to seven additional 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 arranged above the or each stage air inlets per twin heating 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 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 collecting 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 building gauge for Coke ovens teach a connection as possible of all the 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 layer without passage, always alternately up to eg 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 embodiment, at least one in particular centrally arranged step air channel is formed with at least one stage air inlet, in particular with at least one stage air inlet above at least one in the partition 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 in the (respective) partition, which unite above the upper / upper exhaust gas recirculation passage and open in a top step air inlet above all exhaust gas recirculation passages in the flamed heating channel. 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 introduced homogeneously across the width (x-direction) in 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, will a lower edge of the lowest Rezirklationsdurchlasses in the range 0 to 150 mm above the burner levels arranged, about a stabilizing separation layer with a height of about 120 to 130mm, about another passage with a minimum height of eg about 120mm, with this change between passage and Separation layer can extend 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 streams are formed, wherein above and below a gas stage (outlet of a stepped air channel) is provided in each case an exhaust gas recirculation passage. 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 (with respect to a normal to the ground or with respect to the vertical) or at an angle less than 30 °, in particular less than 20 ° or less than 10 ° with respect to the vertical (z) aligned, in particular all inlets in the same direction inclined or aligned. 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 flow rates can flow centrally and almost vertically upwards, ie in the normal direction in the vertical height direction z in the heating channel, and the new, admitted gases can form a Gasteppich 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 shown that the respective Einströmimpuls can be used particularly advantageous for additional suction of flue gas from the unflamed Heizkanal 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 stronger acts. 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), transverse 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 have a rectangular, in particular in the width direction (x), transversely to the expressing direction, elongated geometry or 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 embodiment, the respective exhaust gas recirculation passage has at least one Umstromungskontur with at least one radius and at least one sharp edge of the flow (or spoiler edge). This combined contour provides one particularly good aerodynamic effect and has the advantage that an additional inner circular current can form even 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 flow obstruction can be created in the passage, with the effect that the flow is only forwarded 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, it is also possible to influence the flow profile in a larger width range (x). 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 preferably consists 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 Koksofenvorrichtung previously described, 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 to a partition around by means of at least one coupling upper and lower passage through the partition a internal exhaust gas recirculation is set on an outer circuit current path around the partition around, wherein coke oven gas and / or combustion air and / or mixed gas is admitted at the bottom of the bottom of the respective Zwwiningsheizzuges , so at least one gas from the following group: coke oven gas, combustion air, mixed gas; wherein the exhaust gas recirculation is carried on at least one additional inner circular current path, in particular bounded on both sides by the gases admitted. This allows influencing especially in different height positions.

In this case, the exhaust gas recirculation on one / the respective circuit current path or at least a centric flow path in each case centric (ie closer to the central longitudinal axis in the xy plane) are performed as the admitted gases, in particular bounded on both sides and flows around the admitted gases, in particular in each case fully in a 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.

In one embodiment, the exhaust gas recirculation is directed to at least two additional inner circular current paths. This makes it possible to influence the airfoil and the temperature distribution in other height positions. The at least two additional inner circular current paths can each be arranged distributed concentrically outside the respective outer circular current path and / or next to each other over the width (x) of the heating channel, in particular as a function of the arrangement of a stepped air channel.

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, 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 both for high and mixed gas heating, despite the very different Flame temperature, a comparable low NOx emission can be realized. 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, C02 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 volume flow introduced into the furnace chamber at the combustion air inlet and at the mixed gas inlet is 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 eg in the range of 1 to 2 minutes. The aforementioned object is also achieved according to the invention by using at least one partition wall with at least one more 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 inside 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 / uppermost 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 koksseitige half becomes hotter than the kohleseitige half in many operating conditions, so that it may be sufficient to implement the measures described here in the koksseitigen half, ie at eg 6 to 25, especially in a maximum of 20 in the expressing direction further back arranged twin pairs, so ever Furnace chamber in about 6 to 25, especially 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: petcoke, oil, Bitumensorten eg in the form of scrap tires, coal and coke dust, binders or coking aids such as molasses, oil residues, cellulosic additives, sulfite or sulfate compounds or - lye, wherein the mixture may also have 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.

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, 1.96% CO2, 2.37% H20, with a net calorific value of about 3349

Strong gas: 54.98% H2, 0.66% 02, 5.33% N2, 5.75% CO, 1.52% CO2, 26.66% CH4, 2.74% C2H6, 2.37% H20, with a net calorific value of about 18422

In total, the percentages given in each case according to the selection of the skilled person for the respective gas mixture 100%. 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.

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% 02, 55.7% N2, 23.0% CO, 1 1.2% C02, 1.9% CH4, 0.2% C2H6, 2.4% H20, with a net calorific value of 4396

Super lean mass gas: 45.1% H2, 0.6% 02, 14.4% N2, 8.9% CO, 3.3% C02, 22.2 CH4, 2.3% C2H6, 2.4% H20, with a net calorific value of approximately 15910

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

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

Fig. 1A, 1 B, 1 C, 1 D, 1 E, 1 F, 1 G, 1 H each in a schematic representation in section

Side views and top views Twin heating cables or coke ovens according to the prior art;

Figures 2, 3, 4, 5, 6, 7 in each case in a schematic representation in sectional side views in the width and depth direction twin heating cables according to embodiments. FIGS. 8A, 8B, 8C, 8D, 8E each in schematic representation in section

Side views and in plan views twin heating cables or

Coke oven devices according to embodiments;

9 is 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 is a process diagram relating to the operation of a coke oven apparatus according to embodiments; and

Fig. 1 1, 12 each in a schematic representation in sectional side views

Twin heating cables 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 state of the art, the positions and angular orientations of the individual inlets and passages or flow paths are exemplary only (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.

1A, 1 B, 1 C, 1 D, 1 E, 1 F, 1 G, 1 H show a coke oven 1 in the manner of a horizontal chamber furnace, with a plurality of furnace chambers 2 each with charcoal charge. The furnace chambers 2 have a height z2 of e.g. 6 to 8m up. The furnace chambers 2 are partitioned off by rotor walls 3 which each extend in a yz plane. Between two rotor walls 3 form pairwise heating channels 5.1, 5.2 each have a twin heater 5, the inner wall 5.3 delimits the (free of coal) of gases flowing through the boiler room of the respective furnace chamber. The heating channels 5.1, 5.2 are operated alternately as a flaming or exhaust-carrying heating channel, which requires a switching of the flow direction and in a cycle of e.g. 20 min. he follows.

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

Neighboring twin heating cables are completely sealed off from each other by a partition wall 4a that is completely sealed off.

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

The respective walls are made of stones, each defining a wall layer 3.1. The x-direction indicates the width of the furnace 1, the y-direction indicates the depth (or the horizontal expulsion direction in a horizontal chamber furnace), and the z-direction indicates the vertical (vertical axis). The center 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 plane, and the term "center" or "center" here 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 Koksofengasbeheizung, and another combustion air inlet 7, in particular for mixed gas heating, and a Koksofengas inlet. 8 Gas introduced via the inlets flows upwards on the wall surfaces 4.3 of the partition walls and on the inner walls of the rotor walls.

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

The individual gas flows are described below with reference to FIGS. 1 F to 8E. The gas flow G1 indicates newly introduced or supplied heating gas or combustion air. The gas stream G1 may comprise a gas stream G1a (coke oven gas) and / or a gas stream Gi b (mixed gas). The gas flow G4 indicates recirculation exhaust gases, which are returned or circulated. The gas flow G5 denotes gas or air from a respective combustion stage 4.2, 14.1 1, and the gas flow G6 denotes exhaust gases, which are discharged from the respective heating channel or heating train. With reference to FIGS. 1 D, 1 E, the hitherto customary distances and relative positions of the individual inlets and outlets will be described below.

The distance d4 previously known passages 4.4 in the x-direction to each other is relatively large. The distance d5 of the Koksofengas inlet 8 to the other inlets 6, 7 in the x direction, in particular a distance between the Koksofengas inlet 8; G1a and the other admitted gas flows G1 is comparatively 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 has hitherto been maintained). The distance x6, x8 of the inlet 6, 8 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.

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

Fig. 1 G 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 sealed off by a (intermediate) ceiling 5.7 from the respective twin heating cable. The heating differential 5.6 is independent of the circulating current 9.

On an illustration of the arranged below the burner level 5.4 center 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.

FIGS. 2, 3, 4, 5, 6, 7 show the individual measures according to the invention for optimizing the temperature profile in the respective heating channel. Individual measures are further illustrated in detail in FIGS. 8A, 8B, 8C, 8D, 8E. A coke oven apparatus 10 with furnace chambers 10.2, in particular with horizontal chamber furnace chambers, has a plurality of twin heating units 13 each with a flamed heating channel 11 and an exhaust-carrying heating channel 12. The heating channels define with the inner wall 1 1.1 a heating cable for the passage of gases. The individual heating channels are through partitions (binder wall) 14 with coupling passages

14.2 and partitioning partition walls 14a delimited without passages from each other. In each case at least one stage air channel 14.1 with one or more combustion stages 14.1 1 or inlets or outlets from / to the heating channel is provided in the partitions 14, 14a. Rotor walls 15 delimit the furnace chambers and heating channels in the y-direction.

Gas can flow into the respective heating channel via a plurality of inlets 16, 17, 18, in particular via a first combustion air inlet 16, in particular for coke oven gas heating, via a further 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 of the respective partition wall or rotor wall through the respective heating channel downwards or upwards. In Fig. 2, one of the measures according to the invention is primarily illustrated. A circulating current 19 is formed by a plurality of circulating currents which flow around each other on a plurality of paths. FIG. 2 shows an outer circular current path 19.1, which circumscribes and flows around two further circular current paths 19. 2, 19. 3, the inner circular current paths 19.

19.3 are defined via the corresponding additional exhaust gas recirculation passages 14.2.

Fig. 2 shows an arrangement with three Kreisstrompfaden 19.1, 19.2, 19.3, which extend around an at least approximately at half height position in the heating channel arranged Stufenluftauslass 14.1 1 around. From the Stufenluftauslass 14.1 1 flows step gas G5. Optionally, a plurality of stepped air outlets may be provided, in particular also above the innermost circular flow path 19.3. The optimization of the flow and heat profile can be done primarily by means of the recirculated gas G4, both in the ground area and in several height positions above.

Fig. 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 carried out in particular in the ground area primarily by means of recirculated gas G4, without the requirement of stepped inlet of step gas. In the head area of the heating channel is a Beheizungsdifferential 5.6 provided, which is hinzuschaltbar example by means of pusher blocks regardless of the respective circulating currents.

Fig. 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 arranged under a stepped air outlet 14.1 1 of a centric stepped air duct. 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. Referring to Figs. 5, 6, 7, the cross-sectional area Q14 of the respective coupling passage 14.2 on the inner surface to the heating passage will be described. The cross-sectional area Q14 of passages 14.2 arranged above a stepped-air channel 14.1 is wider or elongated than the cross-sectional area Q14 of passages 14.2 arranged laterally next to the stepped-air channel 14.1.

Fig. 5 shows an arrangement with compared to Fig. 4 a plurality of centric Stufenluftauslässen 14.1 1 and with passages with different cross-section: the lower passages are at least partially elongated in the z-direction, and the upper passages are elongated in the 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 centrically (relatively small distance d2), and in particular also with an optimized flow profile. The comparatively large cross section Q14 of the passage shown on the right side allows a strong flow effect of the introduced gas G1, in particular over a large height section. FIG. 5 shows a distance d2 between an inner wall / edge of the corresponding passage 14.2 and an outer wall / edge of a stepped air duct 14.1, which is arranged in particular centrally in the heating cable, in the x-direction relative to one another. This distance d2 according to the invention is very small, in particular 30 to 100 mm, preferably 50 to 70 mm. In particular, in the case of a centric arrangement of the stepped air duct 14.1, the passages 14.2 according to the invention can be positioned as close as possible in the x direction next to it.

Fig. 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 inlets 14.1 1, two further pairs of lower passages (four passages) in a width position (x) are arranged at least approximately corresponding to the width position of the step gas outlets 14.1 1. 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.

Fig. 7 shows an arrangement with two stage air ducts, which combine together in a vertical position between individual lower passages 14.2 open centrally into the heating channel, wherein in the respective stage air duct optionally further separate stage air outlets can be provided. The central stage air inlet 14.1 1 extends in particular over a width which completely overlaps the upper passage above it. The lower passages are arranged offset from each other in the x-direction by the offset x2. The offset x2 also provides the advantage of a particularly wide, homogeneous flow (without a more strongly flowing core), in particular in the case of relatively wide passages 14.2 in the x-direction. The circulating current can thereby be made even more homogeneous. Optionally, a plurality of upper passages may be provided. Such an offset may also be provided in the arrangement shown in FIG. FIG. 7 illustrates an offset x2 in the x direction. This offset between adjacent passages 14.2 is in particular 50 to 100 mm and provides the advantage of a good heat distribution.

With reference to FIGS. 8A, 8B, 8C, 8D, 8E, the spacings and relative positions of the individual inlets and outlets according to the invention will be described below in a further exemplary embodiment. FIG. 8A schematically shows (in some heating channels) the arrangement of the inlets 16, 17, 18 opposite one another, and in the x-direction at a distance from the central longitudinal axis as close as possible to the rotor walls 15. This arrangement can be chosen at each of the heating channels, or even modified. In Fig. 8B it is shown that the inlets 16, 17, 18 are arranged in the x-direction further outward than the passages 14.2. The passages are arranged at a distance d14 to each other, which is smaller than the distance d15 of the inlets.

In FIG. 8C, it is shown that recirculated gas G4, which is flowed further farther outwards, in each case from admitted gas G1, G1a, Gib, flows around the center of the center, concentrically flowing step gas G5 on both sides. The angle a shown in Fig. 8C, particularly concerning the coke oven gas inlet 18, is set excessively large for better understanding. According to the invention, the angle α can 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.

The passages 14.2 or the stepped gas inlet 14.1 1 shown in FIG. 8C can be varied in the arrangement, number and geometry according to the variants discussed in FIGS. 2 to 7. The individual gas flows G1, G1a, G4, G5 shown in FIG. 8C show how a separation of the gas flows or a parallel flow can be realized according to the invention, at least over a certain height section. The distance d14 of the passages 14.2 in the x-direction relative 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 of the coke oven gas inlet 18 to the further 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 greater than the distance d14, in particular at least 35, 40, 45, 50 or 55 percent greater. 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 (in pairwise passages). Particularly preferably, the distance x14 is 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, 8 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 in each case smaller than the distance x14. In particular, the distance x14 is at least twice or at least three times as large as the distance x16, x18. The individual gas flows will be described below with reference to FIGS. 8B to 8E. The respective gas flow path GP1 identifies inflow paths or flow paths according to the invention for at least one of the gases G1 introduced via the inlets. The respective gas flow path GP4 identifies flow paths according to the invention of recirculated exhaust gas / flue gas G4, and the respective gas flow path GP5 identifies flow paths of step-initiated gas G5 according to the invention.

The inflow angle a, in particular for coke oven gas, illustrated in FIGS. 8C, 8E is preferably less than 30 °, in particular less than 10 °, in each case with respect to the z-axis. The inflow angle α can be realized analogously for the other inlets 17, 18.

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. FIG. 9 shows a passage cross section in the yz plane. The recirculated gas G4 flows through the respective lower passage 14.2 coming from above and also flows back upwards. The gas G4 flows around two rounded flow edges 14.21, and flows past two sharp flow edges 14.22. The partition 14 limits the passage at the top with a convex curvature down. 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 one or more sharp edges 14.22 may limit 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 G4 produce no or only slight turbulences, so that the flow profile can be effectively optimized by means of the inlets.

10 schematically illustrates that the coke oven device 10 may have a control unit 20, configured for controlling / regulating one of the volume flows V (t) described above, in particular at least the volume flows G1, G1a, G1b, G4, G5, G6. The control and adjustment of the volume flows allows influencing the flow and temperature profile in the respective heating channel 1 1, 12. Thus, via the volume flows indirectly also the NOx emission can be adjusted.

FIGS. 11, 12 show variants of the embodiment shown in FIG. In Fig. 11, some of the upper passages disposed above the uppermost stage air outlet are formed in pairs, with a single larger, wider lower passage being provided.

In FIG. 12, only two recirculation passages are provided between the lowermost stage 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 positions of the inlets and outlets shown in FIGS. 2 to 12 are shown by way of example. Each inlet or passage can be arranged and aligned individually. The exemplary embodiments shown can in particular also be varied by varying the arrangement of the lower passages.

With particular reference to the exemplary embodiments of FIGS. 5, 6, 11, 12, a variation of the arrangement and size of the passages, in particular the passages arranged above the uppermost stage air outlet, and / or the passages arranged in a height position between individual stage air outlets, can be achieved by alternation done on paired 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 chamber oven

2 oven chamber with charcoal charge

3 rotor wall

3.1 wall position

4 coupling partition wall 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 cables (in pairs of two vertical heating cables)

5.1 flamed heating channel (vertical heating cable)

5.2 exhaust gas 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

8 Koksofengas inlet or Koksofengas nozzle

9 circulating current

10 Koksofenvorrichtung, in particular with horizontal chamber furnace

10.2 Furnace chamber

1 1 flamed heating channel (vertical heating cable)

1 1.1 Inner wall

12 exhaust-carrying heating channel (vertical heating cable)

13 twin heating cables (in pairs 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

14.1 1 combustion stage or step air inlet or outlet on the step channel from / to the heating channel

14.2 two heating channels coupling passage

14.21 rounded edge of the stream

14.22 sharp edge of the stream

14.3 Inner surface of the partition

15 rotor 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 circular current

19.1 outer circular current path

19.2 (first) inner circular current path

19.3 (further) internal circular current path

20 Logic unit or control unit 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 of previously known passages 4.4 of a twin heating cable in the x-direction to each other

d5 distance of the coke oven gas inlet 8 to further inlets in the x-direction, in particular distance between the Koksofengas inlet 8; G1a and the other admitted gas flows G1

d14 Distance between passages 14.2 according to the invention of a twin heating cable in the x direction relative to one another

d15 inventive distance of the coke oven gas inlet 16 to further inlets in x-

Direction, especially between G1 and G1a G1 heating gas or combustion air

G1a coke oven gas

Gi b mixed gas

G4 recirculation exhaust gas

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-in gas

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 stone temperature

T2 (gas) temperature in the heating cable / heating channel

T3 temperature in the oven chamber

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 of the previously known passage 4.4 to the inner wall of the rotor wall 3 x6 distance of the known inlet 6 to the inner wall of the rotor wall 3 x8 distance of the known inlet 8 to the inner wall of the rotor wall 3 x14 distance of the passage 14.2 according to the invention to the rotor wall

x16 distance of the inlet 16 according to the invention to the rotor wall

x18 distance of the inlet 18 according to the invention to the rotor wall y depth or horizontal Ausdrückrichtung

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)

Claims

claims:

A coke oven apparatus (10) for producing coke by coking coal or coal mixtures, the coke oven apparatus being arranged for minimizing nitrogen oxide emissions by internal thermal energy balance by means of coke own gases (G1, G4, G5) internally at the coke oven apparatus, with a plurality of Twin Heizzügen (13) each with a gas-fired heating channel (1 1) and an exhaust gas flowing downwardly flowing heating channel (12), which heating channels in pairs by a partition (14) delimited from each other and by two opposing rotor walls (15) of a respective furnace chamber (10.2) are sealed off, wherein the pairwise heating channels are fluidically coupled to one another by means of an upper coupling passage (14.2) and by means of a lower coupling passage for internal exhaust gas recirculation (19) on an outer circular flow path (19.1). 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);

characterized in that the respective partition wall (14) has at least one further lower and upper coupling passage (14.2), which are arranged in a central height position closer to the center of height of the heating channels than the outer circular flow and are arranged for an additional inner circular current upwards and downwards bottom for forming an intermediate layer on an additional inner circular current path (19.2, 19.3).

2. Koksofenvorrichtung according to claim 1, wherein the additional inner Kreisstrompfad (19.2) via paired lower and / or upper passages (14.2) extends, which are each arranged in pairs in at least approximately the same height position.

3. Koksofenvorrichtung according to any one of the preceding claims, wherein by means of the passages (14.2) at least one further inner Kreisstrompfad (19.3) is formed, which is flowed around by at least two outer circular currents on outer Kreisstrompfaden (19.1, 19.2).

4. Koksofenvorrichtung according to any one of the preceding claims, wherein at least one exhaust gas recirculation passage (14.2) with respect to the width (x) of the heating channel centric is arranged as at least one of the inlets (16, 17, 18) and a centric flow path (GP4) flows around defined by at least one of the admitted gases (G1, G5), in particular all exhaust gas recirculation passages.

5. Coke oven device according to one of the preceding claims, wherein the respective combustion air inlet (16) and / or the respective mixed gas inlet (17) and / or the respective Koksofengas inlet (18) have a cross-sectional area of at most 0.06m ² ; and / or wherein the cross-sectional area of the respective lower and / or upper exhaust gas recirculation passage (14.2) is greater than 0.005M ^2, in particular greater than 0.01 m ^2.

6. Coke oven device according to one of the preceding claims, wherein the combustion air inlet (16) and / or mixed gas inlet (17) and / or Koksofengas inlet (18) at an angle (a) of 0 ° with respect to the central longitudinal axis of Heizkanals or at an angle less than 30 °, in particular less than 20 ° or less than 10 ° are aligned; 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 (1 1, 12) opens.

7. Koksofenvorrichtung according to any 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 (14.1 1) is formed; or wherein in the partition wall (14) at least two in particular parallel arranged stepped air channels (14.1) are formed, which unite above the upper / upper exhaust gas recirculation passage (14.2) and in a top stage air inlet (14.1 1) above all exhaust gas recirculation passages (14.2) into the flamed heating channel (1 1).

8. Koksofenvorrichtung according to any one of the preceding claims, wherein in at least one of the partitions (14) at least two, in particular parallel stepped air passages (14.1) are formed, which above the upper / top exhaust gas recirculation passage (14.2) in two upper stage air inlets (14.1 1) above all Abgasrezirkulations- passages in the flamed heating channel (1 1) open.

9. Koksofenvorrichtung according to any one of the preceding claims, wherein the respective exhaust gas recirculation passage (14.2) at least one rounded flow edge (14.21) and / or having convex curvature, in particular with a radius of at least one quarter of the wall layer or at least 30 °, in particular a rounded flow edge or convex curvature lying inside with respect to 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 120 mm, in particular a sharp flow edge or concave outside with respect to the respective circular flow path curvature; 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.

10. A method for operating a coke oven device (10) for producing coke by coking coal or coal mixtures with optimized minimized nitrogen oxide emissions by internal thermal energy balance means of coke own gases (G1, G4, G5) by measures internally to the coke oven apparatus, in particular for operating a Coke oven apparatus according to one of the preceding claims, wherein in a respective twin heating cable (13) of the coke oven apparatus with a flamed heating channel (1 1) and an exhaust gas carrying heating channel (12) by means of at least one coupling upper and lower passage (14.2) through a partition wall (14) internal exhaust gas recirculation (19) on an outer circular flow path (19.1) is set around the partition around, at the bottom of the bottom (5.4) of the respective Zwwiningsheizzuges at least one gas from the following group is admitted: coke oven gas (G1a), combustion air (G1) , Mixed gas (Gi b),

That is, the exhaust gas recirculation (19) is guided on at least one additional inner circular flow path (19.2, 19.3), in particular bounded on both sides by the admitted gases.

1 1. A method according to the preceding method claim, wherein the exhaust gas recirculation (19) on at least two additional inner Kreisstrompfaden (19.2, 19.3) is performed.

12. The method according to any preceding method claims, wherein at least one additional inner circular flow (19.2, 19.3) centric than the admitted gases (G1) and further inside than the outer circular current path (19.1) and bounded by the outer Circular current path is set, in particular via at least one pair of additional passages (14.2) above and below.

13. The method according to any one of the preceding method claims, wherein the proportion of 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 set 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.

14. The method according to any 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 (1 1, 12).

15. 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 from 5 to 75 % or 15 to 50% of the height of the heating channel or over a height section from 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.

16. The method according to any one of the preceding method claims, wherein the proportion of the 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 introduced into the heating channels (1 1, 12) volumetric flows is set as follows: <30% through the combustion air inlet (16), <30% through the mixed gas inlet (17), and> 40th % through the recirculation passages and optionally at least one stage air inlet (14.1 1), in particular with strong gas heating; and / or wherein the volumetric flow introduced into the furnace chamber at the combustion air inlet and at the mixed gas inlet is adjusted to between 45 and 55% of the volume flow introduced through the recirculation passages and optionally the at least one stage air inlet, in particular with high gas heating.

17, control device (20) arranged for carrying out a method according to one of the preceding method claims, wherein in the heating channels (1 1, 12) introduced volume flows (G1, G4, G5) are set according to the proportions of claim 13.

18. The use of lean heavy gas with lowered lower heating value for operating a coke oven device according to a method according to one of the preceding method claims, in particular in a coke oven device according to one of the preceding device claims.