EP3650756B1 - Demounatble lance system - Google Patents

Description

The present invention relates to a lance system that can be dismantled, a reaction space containing the lance system and a method for reducing the concentration of pollutants in combustion gases.

Technical area

When carbon-containing materials and fossil fuels are burned, for example in power plants and systems for steam generation, waste incineration plants, or cement works, sulfur dioxide (SOx) and nitrogen oxides (NO _x ) are produced. In accordance with legal requirements, measures to control the combustion process or to clean flue gases or combustion gases must be established so that only little NO _{x is produced or NO x} and SO _x present in combustion gases are reduced in order to reduce their entry into the atmosphere .

The formation of NO _x is subject to complex reaction mechanisms, the most important _{sources of NO x being} the oxidation of the nitrogen in the combustion air (thermal NO _x ) and the oxidation of the fuel _{nitrogen (fuel NO x} ).

Thermal NO _x essentially arises at temperatures that are greater than around 1,200 ° C to 1,500 ° C, because only at these temperatures does the molecular oxygen present in the air noticeably change into atomic oxygen (thermal oxidation) and mix with the nitrogen in the air connects. The rate of formation of thermal NO _x depends exponentially on the temperature and is proportional to the oxygen concentration.

The primary nitrogen compounds contained in the fuel first break down into secondary nitrogen compounds (simple amines and cyanides), which are converted to _{either NO x} or N _{2 in the course of combustion.} If there is a lack of oxygen, the formation of N _{2 is} preferred or the NO _x formation is suppressed or even reversed. The formation of fuel NO _x is only slightly temperature-dependent and also takes place at low temperatures.

_{In the state of the art, NO x is reduced} in power plants by means of primary measures such as air staging at the burner and above the furnace height. The air staging above the combustion chamber height is carried out in such a way that the burner belt area is mostly operated substoichiometrically. In this way, the burners only receive part of the amount of air required for complete combustion. The remaining air required for burnout (= ABL = burnout air) is then usually added at a considerable distance above the burner belt. This procedure is known as the OFA method (Over-Fire-Air). It is added using so-called ABL nozzles. The two basic types of ABL nozzles are wall nozzles and ABL lances.

Use of SNCR as a secondary measure to reduce nitrogen oxide

The invention relates to a method and devices including reaction chambers for reducing undesirable substances by injecting a reactant into an exhaust gas or flue gas, in particular into the exhaust gas from cement works, in which the reactant is injected into the flue gas by means of lances. The invention also relates to a lance or a lance system for injecting reactants to reduce undesirable substances in the flue gas. In addition, the invention also relates to a suitable reaction chamber which is equipped with such a device according to the invention in order to be able to carry out the method.

Methods and devices of the aforementioned type are already known. The reactants are, for example, ammonia and / or urea, which can reduce the proportion of nitrogen oxides in the flue gas. Corresponding processes are called selective non-catalytic reduction (SNCR; selective non-catalytic reduction). With the selective non-catalytic reduction (SNCR) of nitrogen oxides, reducing agents are injected in an aqueous solution (typically ammonia water, urea) or in gaseous form (ammonia) into the hot flue gases of a combustion system. The reaction of the reducing agent with nitrogen oxide and oxygen produces molecular nitrogen, water and carbon dioxide. For example, for ammonia or urea as the reducing agent, the following reaction, shown in simplified form, takes place:

4NH ₃ + 4NO + O ₂ → 4N ₂ + 6H ₂ O

2NH ₂ CONH ₂ + 4NO + O ₂ → 4N ₂ + 2CO ₂ + 4H ₂ O

The optimum temperature range for the reactions described is between 850 and 1,000 ° C, depending on the composition of the flue gas.

One of the main difficulties with SNCR technology is mixing the reducing agent into the flue gas in the correct temperature window. Basically, the SNCR technology is successfully used in small and medium-sized boilers and especially in waste incineration plants and cement works. The advantage here is the small cross-sections of the reaction or combustion chambers, so that the SNCR technology can be used effectively and optimally.

In cement works, cement is produced in a continuous process using the dry process in rotary kilns. The raw materials such as limestone, clay, sand, but also often residues such as "fluff" or "bram", etc. are ground and dried at the same time, then heated and then burned to cement clinker. The cement clinker is burned in rotary kilns that are slightly inclined. As a result of the inclination and rotation of the furnace, the preheated raw meal placed at the upper end runs towards a coal dust, oil or gas flame that burns at the lower end of the furnace. In the area of the flame with gas temperatures of 1,800 to 2,000 ° C, fuel temperatures of 1,350 to 1,500 ° C are reached. The raw meal is preheated and calcined either in the rotary kiln itself or in a separate preheater, which is usually constructed from a device consisting of several cyclones or in a separate calciner (Calcining reactor). The hot exhaust gases from the rotary kiln flow through the calciner and the preheater from bottom to top, and the dry raw meal is added to the exhaust gases before the top cyclone stage, separated from the gas in the individual cyclones and resuspended in the gas flow before the next cyclone stage. The raw meal is usually preheated to a temperature of approx. 800 ° C in the preheater. Partial calcination of the raw meal can already take place in the cyclone preheater. The raw meal is then further calcined in the calciner before it enters the rotary kiln.

In the rotary kiln, at the high temperatures of the combustion flame, nitrogen oxides are formed in considerable quantities, which have to be removed from the exhaust gases.

SNCR systems for power plants, waste incineration plants and cement plants have already been described in the prior art. As a rule, only very short injection lances are used, the nozzles either essentially closing off with the reactor or channel wall or not protruding more than a few decimeters into the hot space. The reason for this is that a temperature of 850 to 1,000 ° C is required for the functioning of an SNCR and a lance of this temperature that protrudes into the room for a long time and, especially when used in cement plants, extremely high dust loads in the flue gas and thus also a strong formation would be exposed to deposits or erosion.

The central areas of the flue gas flows in flue gas ducts and combustion chambers with large dimensions in cross section can only be reached, if at all, with a large amount of reagents, if at all, by means of nozzles arranged in the wall. With ever stricter limit values for NO _x (e.g. <200 or even 150 mg / Nm ³ dry, based on different oxygen concentrations depending on the application (e.g. based on 10% O ₂ in cement plants and based on 6% O ₂ in coal-fired power plants) the middle of the channel or combustion chamber can be better reached with reagent, with disproportionately high amounts of ammonia or urea solution being used for the SNCR, which also remain in not inconsiderable amounts without a reaction partner being found have unreacted as so-called ammonia slip in the flue gas. Part of this ammonia slip burns as a result, and part of it leaves the gas space via the chimney. In addition, there is also the risk that large amounts of unreacted ammonia will end up in the filter ash, which is undesirable due to the odor and toxicity. In any case, the input costs increase significantly due to the non-earmarked contribution of the input material not involved in the reaction.

So describes the German patent application DE 43 13 479 a process for denitrification of the exhaust gases resulting from the production of cement, ammonia being added to the exhaust gas after leaving the rotary kiln at a temperature of 750 to 950 ° C, and that the exhaust gas at a temperature of 300 to 450 ° C with catalytically active substances is brought into contact. The injection nozzle for the ammonia is not described in more detail in the document.

the WO 93/19837 discloses a method for denitrifying the exhaust gases that are generated during the production of cement. After leaving the rotary kiln, an ammonia solution is added to the exhaust gas through nozzles located on the wall.

the WO 2014/114320 describes a method for treating exhaust gases containing nitrogen oxides from industrial processes, such as flue gases, to reduce the nitrogen oxide content by means of chemical reduction of the nitrogen oxides. The reducing agent is injected into the reaction space through which the exhaust gases flow via nozzles arranged in the wall of the reaction space.

the EP 2 962 743 A1 discloses the introduction of reducing agent into a boiler. The reducing agent is injected with the aid of lances into which one or more injectors for reducing agents are inserted. Burnout air, for example, is also supplied to the lances. The reducing agent is injected into the lance and leaves the lance together with the burnout air through the nearest outlet openings of the lance into the flue gas.

the U.S. 5,342,592 discloses an injection lance having an outer tubular jacket with a plurality of openings and a cooling circuit. This tubular casing has an inner channel into which an injection lance is inserted. This in turn consists of an inner tube and an outer tube, with an intermediate space being formed. The reducing agent is passed through the inner tube and the propellant is passed through the space. The reducing agent enters the flue gas flow directly from the inner pipe and via radial channels branching off from it and bridging the intermediate space. The propellant meets the reducing agent at the outlet of these channels and enters the flue gas flow.

the U.S. 5,281,403 describes an injection lance system with an inner tube and an outer tube, which form a space through which the reducing agent is fed into a boiler. The reducing agent is introduced into the inner tube, which is provided with a plurality of nozzles along the longitudinal direction of the inner tube. A carrier gas is introduced into the cavity of the outer tube. The nozzles of the inner tube inject the reactant into the flue gas through a correspondingly arranged outlet opening in the outer tube, the reactant being mixed at the same time with the carrier gas, which is directed into the cavity of the outer tube and also leaves the lance system through the said outlet opening.

the AT 515821 A1 discloses a lance system and method for injecting a liquid reactant into a flue gas stream. In a jacket tube through which cooling air flows, the central tube for the liquid reactant and a tube concentrically surrounding this for the atomizing medium are arranged. At least the two inner tubes are cranked at the top.

As explained above, various devices for injecting reagents for reducing the NOx concentration in calciners of cement works were already known in the prior art. In addition to the wall nozzles described, lances were also used for this, such as, for example, two-substance nozzles spraying downwards through which an ammonia-water-air mixture is finely atomized in the direction of the flue gas flow. The nozzle of such a conventional lance is surrounded by an annular gap through which a cone of enveloping air or curtain air is generated around the nozzle by means of a high overpressure, which is intended to protect the nozzles from caking from the cement raw meal flying past in the calciner.

However, these prior art nozzles proved to be unsuitable in real operation of a cement works, which is why the area around the nozzles and the nozzles themselves were covered by thick crusts and caking of raw meal after a short operating time of only a few hours. The reason for this rapid growth of stable encrustations lies on the one hand in the extraordinarily high dust content in the calciner gas volume flow of approx. 900 g / Nm ³ and on the other hand in the fact that this dust (i.e. the cement raw meal) must naturally have the property to stick to each other and to walls. With conventional nozzles or lance systems, a uniform spray pattern in all spatial directions can no longer be maintained after a few hours of use. Furthermore, cleaning the nozzles as often as would be necessary for this is out of the question for the operation of a cement works. It has therefore been desirable to provide injection lances and systems that require cleaning no more than once a week or less.

A further problem of the injection lances according to the prior art was that after a short time of operation thick and well adhering caking of raw meal occurs on the section of the injection lance arranged within the reactor space or the calciner, so that the complete lances are only extremely Pull it out completely again with great effort and effort. Therefore, maintenance and repair work on such conventional lances are very laborious and time-consuming and costly.

Object of the invention

The object of the present invention was therefore to provide lance systems, in particular for the injection of reagents for flue gas cleaning, such as with regard to NO _x , and in particular in reaction spaces such as calciners, flue gas ducts, boilers or fireplaces, these reaction spaces being traversed by hot flue gases with a high dust load and the These hot smoke gases flow around lance systems, the lance systems allowing longer maintenance intervals and, in particular, maintenance and repair work can be carried out more quickly and with less effort.

• ein Hüllrohr, das konfiguriert ist mindestens zum Teil innerhalb des Reaktionsraumes angeordnet zu werden;
• eine Eindüslanze mit einem Zuführrohr für ein Flüssigreagenz, ggf. einem Zuführrohr für Druckluft, und mit der Düse zum Eindüsen des Reagenz, wobei die Eindüslanze in das Hüllrohr eingeschoben werden kann;

wobei erfindungsgemäß
das Hüllrohr an seinem distalen Ende eine Abschlussplatte aufweist, die den Innenraum des Hüllrohrs nach außen hin begrenzt, wobei die Abschlussplatte eine innenliegende Öffnung zur Anordnung der Düse aufweist und die Ebene der Abschlussplatte des Hüllrohrs in einem Winkel von 25 bis 65° zur Längsachse des Hüllrohrs angeordnet ist,
die Längsachse der Düse der Eindüslanze im eingebauten Zustand in einem Winkel von 25 bis 65° zur Längsachse des Hüllrohrs abgewinkelt ist und zur Abschlussplatte hin geneigt ist; und
die Düse der Eindüslanze im Verhältnis zur innenliegenden Öffnung der Abschlussplatte so angeordnet und ausgerichtet ist, so dass die Düse das Reagenz durch die innenliegende Öffnung der Abschlussplatte hindurch eindüsen kann.The technical object is achieved by a lance system for introducing reagents by means of a nozzle into reaction spaces through which combustion gases flow, the lance system comprising:

• a cladding tube which is configured to be arranged at least in part within the reaction space;
• an injection lance with a supply tube for a liquid reagent, possibly a supply tube for compressed air, and with the nozzle for injecting the reagent, wherein the injection lance can be pushed into the cladding tube;

being according to the invention
the cladding tube has an end plate at its distal end which delimits the interior of the cladding tube to the outside, the end plate having an internal opening for the arrangement of the nozzle and the plane of the end plate of the cladding tube at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube is arranged
the longitudinal axis of the nozzle of the injection lance in the installed state is angled at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube and is inclined towards the end plate; and
the nozzle of the injection lance is arranged and aligned in relation to the inner opening of the end plate so that the nozzle can inject the reagent through the inner opening of the end plate.

As mentioned above, reagents, in particular in the form of fluids, ie in particular in the form of gases and / or liquids, are injected into combustion gases in order to reduce the pollution. The reaction chambers through which combustion gases flow are preferably calciners or calcining reactors, flue gas ducts, boilers or combustion chambers of the reaction chamber protruding end of the lance system, beveled. The “distal end” of the lance system is the end which protrudes into the interior of the reaction space.

According to the invention, the angle of the longitudinal axis of the nozzle to the longitudinal axis of the cladding tube is in a range from 25 to 65 °. The definition, according to which the longitudinal axis of the nozzle of the injection lance in the installed state is angled at an angle of 25 to 65 ° to the longitudinal axis of the cladding tube and is inclined towards the end plate, means that the longitudinal axis of the nozzle is at an angle of 90 ° +/- 10 ° to the level of the end plate. The angle of the longitudinal axis of the nozzle to the longitudinal axis of the cladding tube is preferably in the range from 30 to 60 °, more preferably in the range from 35 to 55 °, and particularly preferably around 45 °.

The end plate can be flat or concave or convex. If the end plate is arched, the plane of the end plate refers to the imaginary plane that is defined by the edge of the end plate.

According to the invention, the nozzle of the injection lance is arranged and aligned in relation to the inner opening of the end plate so that the nozzle sits in the inner opening of the end plate, a gap running completely around the nozzle remaining or being able to remain around the nozzle. The "inner opening" of the end plate is an opening or a corresponding through hole arranged within the surface of the end plate. This opening or this through hole can be arranged essentially centered with respect to the surface of the end plate. Due to the arrangement of the end plate inclined to the longitudinal axis of the cladding tube, it has an oval shape. In a preferred embodiment, the nozzle of the injection lance in the installed state passes at least partially through the inner opening of the closing plate, with a completely circumferential or uninterrupted gap particularly preferably remaining between the nozzle of the injection lance and the edge of the inner opening of the closing plate.

The inventive setting of the angle of the longitudinal axis of the nozzle to the longitudinal axis of the cladding tube, in comparison to a right angle, in conjunction with the likewise inclined end plate, allows the injection lance to be withdrawn through the cladding tube, which remains in place in the reaction space . In this way it is also made possible that the nozzle or the nozzle head a piece, preferably 6 to 8 mm, can protrude beyond the end plate in the direction of the reaction space, which would not be possible with a 90 ° deflection. This offers the advantage that the risk of caking due to liquid droplets spraying directly from the nozzle onto the parts of the cladding tube surrounding the nozzle is greatly reduced. It is therefore further preferred that the nozzle of the injection lance protrudes through the internal opening of the closing plate in the installed state, preferably 2 to 10 mm and particularly preferably 4 to 8 mm through the internal opening of the closing plate. An alignment of the nozzle along the longitudinal axis of the cladding tube (angle 0 °) corresponding to the wall nozzles of the prior art, on the other hand, has the disadvantage of less coverage of the cross section of the reaction space with reagent.

In a preferred embodiment, in the installed state, a completely circumferential or uninterrupted gap remains between the nozzle of the injection lance and the edge of the inner opening of the closing plate.

In a further preferred embodiment, the end plate of the cladding tube is dimensioned such that a completely circumferential or uninterrupted gap is provided between the edge of the end plate and the inner wall of the cladding tube.

In a particularly preferred embodiment, when installed, there remains a completely circumferential or uninterrupted gap between the nozzle of the injection lance and the edge of the inner opening of the end plate, as well as a completely circumferential or uninterrupted gap between the edge of the end plate and the inner wall of the cladding tube. According to this embodiment, it is achieved during operation that the enveloping air emerging from the cladding tube through the two gaps surrounds the reducing agent / air mixture injected through the nozzle in the form of two enveloping air veils lying one inside the other.

With these measures, according to the preferred embodiments of the present invention, two concentric enveloping air ring gaps are now provided around the nozzle instead of just one enveloping air ring gap, as was previously the case in the prior art. The outer one The gap runs uninterruptedly around the inclined end plate and flushes the gap between the outer area of this plate and the inner area of the lance tube. If cement dust gets through this outer veil of the enveloping air despite the repellent outer enveloping air curtain, the cement dust is then finally prevented from reaching the nozzle itself and its liquid droplets by the inner enveloping air curtain that directly surrounds the nozzle.

In a further preferred embodiment of the lance system, the end plate of the jacket tube has further through holes or jacket air holes. These serve to keep the inclined end plate free of cement dust with enveloping air that flows out of the interior of the enveloping tube. 3 to 10 enveloping air holes, preferably 4 to 6, particularly preferably 5 enveloping air holes, are preferred around the inner opening of the end plate, ie in the installed state, around the nozzle or around the gap between the nozzle and the edge of the inner opening of the end plate are arranged.

• über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte des Hüllrohrs;
• über den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs;
• über ggf. weitere vorhandene Durchgangslöcher in der Abschlussplatte.

Therefore, in a further embodiment, the lance system has an interspace which is formed between the outer wall of the injection lance and the inner wall of the cladding tube, the interspace being in fluid communication with the outside at least via the following outlet openings:

• across the gap between the nozzle of the injection lance and the edge of the inner opening of the end plate of the cladding tube;
• across the gap between the edge of the end plate and the inner wall of the cladding tube;
• via any additional through holes in the end plate.

• die Eindüslanze mittels an der inneren Wand des Hüllrohrs angeordneten rampenartig abgeschrägten Schienen, in die seitlich an der Eindüslanze angeordnete Führungsnasen eingreifen, in das Hüllrohr eingeschoben und innerhalb des Hüllrohr ausgerichtet und lösbar fixiert werden kann, oder
• die Eindüslanze mittels an der inneren Wand des Hüllrohrs angeordneten Führungsnasen, die in seitlich an der Eindüslanze angeordnete rampenartig abgeschrägte Schienen eingreifen, in das Hüllrohr eingeschoben und innerhalb des Hüllrohr ausgerichtet und lösbar fixiert werden kann. Eine weitere bevorzugte Ausführungsform des Lanzensystems ist so ausgestaltet, dass der Abstand zwischen der Eindüslanze und Hüllrohr durch zusätzliche Abstandhalter aufrechterhalten wird, wobei diese Abstandhalter vorzugsweise ausgewählt sind aus der Gruppe bestehend aus Flossen, Stiften, Stangen, Stegen oder Leitblechen.

In a further embodiment it is preferred that the lance system is constructed in such a way that

• the injection lance by means of ramp-like bevelled rails arranged on the inner wall of the cladding tube, into which guide lugs located on the side of the injection lance engage, can be pushed into the cladding tube and aligned and releasably fixed within the cladding tube, or
• the injection lance can be pushed into the cladding tube and aligned and releasably fixed within the cladding tube by means of guide lugs arranged on the inner wall of the cladding tube, which engage in ramp-like inclined rails arranged on the side of the injection lance. Another preferred embodiment of the lance system is designed in such a way that the distance between the injection lance and cladding tube is maintained by additional spacers, these spacers preferably being selected from the group consisting of fins, pins, rods, webs or baffles.

The supply for the reducing agent is preferably designed as a two-substance nozzle, the reducing agent being introduced together with a propellant (preferably compressed air). In an advantageous and preferred manner, the injection lance has a central line for introducing the reducing agent (liquid reagent feed pipe), as well as an interspace between the central line and the inner wall of the injection lance, through which a propellant (compressed air) is passed separately from the reducing agent feed is to be mixed in the nozzle with the reducing agent and atomized this. In a further embodiment, it is therefore preferred that the injection lance has a liquid reagent feed pipe and a compressed air feed pipe, the liquid reagent feed pipe preferably running in the compressed air feed pipe.

For the assembly of the lance system according to the invention, the angled nozzle, which is firmly connected to the supply tube for reagent and to the supply tube for compressed air, is automatically returned to its end position, ideally centrally in the inner opening, by means of lateral guide lugs or ramp-like bevelled rails when inserted into the cladding tube the end plate pushed in. Correct positioning is important because the gap between the nozzle and the edge of the inner opening should be approximately the same width all around.

Optionally, the gap around the nozzle can also be provided somewhat wider in the axial direction, ie forwards and backwards along the insertion direction, since here the different temperature expansion between the outer jacket tube and the injection lance requires a certain amount of leeway.

Reaction spaces, such as calciners, flue gas ducts or boilers or fireplaces, some of which have large cross-sections, must be supplied with appropriate reagents over the entire cross-section for optimal pollutant reduction. Compared to the injection of reagents with nozzles arranged directly in the wall of these reaction spaces, as is usually done in the prior art, a far more effective flue gas cleaning effect can be achieved with the lance system according to the invention and thus a lower pollutant clean gas value with moderate use of reagents . With the lance system according to the invention, the reagents can now also be reached in the central areas of the cross-section of reaction spaces which previously could not be supplied with reagent. In the example of the SNCR, this means that because the center of the reaction chamber can also be reached more easily, a lower final clean gas value, for example of NO _x, and thus compliance with a more stringent limit value (e.g. <200 or even <150 NO _x mg / Nm ³ dry, based on 6% O ₂ ) can be achieved without having to use a disproportionate amount of ammonia or urea solution, which then also remains in not inconsiderable amounts afterwards, without having found a reaction partner, unreacted as so-called ammonia slip in the flue gas on the chimney . There is also the risk that larger amounts of unreacted ammonia will end up in the filter ash, which is undesirable due to its toxicity and smell.

Furthermore, the lance system according to the invention can also be used in dust-laden combustion gases, especially in calciners in cement works, because the invention provides measures for quick and easy dismantling and dismantling of the lance system for subsequent maintenance and cleaning, and preferably means to protect the nozzles from caking.

1. a) Reagenzien in Form eines fluiden Gemisches enthaltend Reduktionsmittel durch ein in der Eindüslanze verlaufendes Flüssigreagenz-Zuführrohr zuzuführen und von dort über die Düse direkt durch die innenliegende Öffnung der Abdeckplatte des Hüllrohrs hindurch nach außen zu leiten;
2. b) Hüllluft in den Zwischenraum zwischen der Eindüslanze und der inneren Wand des Hüllrohrs getrennt zuzuführen;
3. c) einen Teil der Hüllluft aus b) über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte aus dem Hüllrohr austreten zu lassen, wodurch ein innerer Hüllluftschleier gebildet wird; und
4. d) einen anderen Teil der Hüllluft aus b) durch den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs aus dem Hüllrohr austreten zu lassen, wodurch ein äußerer Hüllluftschleier gebildet wird.

It is also preferred that the lance system is constructed,

1. a) to supply reagents in the form of a fluid mixture containing reducing agents through a liquid reagent supply tube running in the injection lance and from there via the nozzle directly to the outside through the inner opening of the cover plate of the cladding tube;
2. b) supplying enveloping air separately into the space between the injection lance and the inner wall of the enveloping tube;
3. c) to let some of the enveloping air from b) escape from the enveloping tube via the gap between the nozzle of the injection lance and the edge of the inner opening of the closing plate, whereby an inner enveloping air curtain is formed; and
4. d) to let another part of the enveloping air from b) emerge from the enveloping tube through the gap between the edge of the end plate and the inner wall of the enveloping tube, whereby an outer enveloping air curtain is formed.

It is further preferred that this supply for the enveloping air for the intermediate space is arranged in an outer section of the lance system, which is designed to supply the intermediate space between the injection lance and the enveloping tube with the enveloping air. Thus, the cladding tube has an inner end (which protrudes into the reaction space) and an outer end, the outer end being in fluid communication with a supply for introducing the enveloping air into the intermediate space.

The enveloping air introduced via the space between the cladding tube and the injection lance of the lance system serves to cool the lance system and to avoid deposits on the nozzle. The enveloping air is introduced into the enveloping tube in the outer section of the lance system and passed on into the space between the injection lance and the enveloping tube. The enveloping air finally passes through the gap around the nozzle (or through the inner opening of the end plate of the cladding tube), through the gap between the outer edge of the end plate and the cladding tube and possibly through further through holes in the end plate to the outside, ie into the interior of the reaction chamber. The enveloping air in the form of two enveloping air veils lying one inside the other (the inner and outer enveloping air veil) surrounds the reducing agent / air mixture injected through the nozzle and finally meets the combustion gas. In particular, the enveloping air or the enveloping air curtain also prevents caking on the nozzle or on the outlet openings by keeping away any moistened and agglomerated dust particles.

With the lance system according to the invention, reagents such as nitrogen oxide reducing agents can be mixed into a combustion gas, distributed as uniformly as possible.

In a further preferred embodiment, the lance system is designed to introduce reducing agents for the selective non-catalytic reduction of nitrogen oxides in combustion gases into the reaction spaces through which combustion gases flow.

In a further embodiment, the lance system has an inner section which is designed to be arranged within the reaction space, and an outer section designed to be arranged outside of the reaction space, wherein a quick release coupling is provided to connect the injection lance through the im Insert the outer section arranged opening of the cladding tube into the cladding tube and fasten by means of the quick release coupling. The quick release coupling enables the injection lance to be installed and removed quickly and easily. With the quick release coupling, the connection between the two lance parts "cladding tube" and "injection lance" can be made quickly and also released again. Up to now, a flange with several screws was provided at this point, which, however, means a much higher effort for maintenance and repair work on the lance system.

The lance system is also preferably designed to remove combustion gases with a dust load of 1 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, preferably from 30 g / Nm ³ to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, more preferably from 100 g / Nm ³ to 1000 g / Nm ³ with a volume flow of 10,000 to 2,000,000 m ³ / h. The dust load of combustion gas streams in the combustion chamber of power plants is typically in the range from 1 g / Nm ³ to 10 g / Nm ³ , while the dust load in, for example, calcining reactors of cement works is in the range from 100 g / Nm ³ to 1000 g / Nm ³ .

In a preferred embodiment, the cladding tube has a round or circular cross section.

In a preferred embodiment of the lance system, the diameter of the cladding tube decreases in the direction of the end protruding into the reaction space, i.e. in the direction of the inner (distal) end. This measure serves to maintain the speed of the mass flow in the space and to reduce the weight of the lance system. This measure is usually only necessary for longer lances. The tapering of the cladding tube can take place continuously or in stages.

In a preferred embodiment of the lance system, at the end protruding into the reaction space, a protective hood is formed as an extension of the cladding tube, which partially surrounds the end plate and protrudes beyond the end plate. The protective hood preferably extends over a distance along the circumference of 1/3 to ½ of the circumference of the cladding tube. The protective hood is arranged on the side from which the flow of the combustion gases or the dust particles, in particular the cement dust particles, comes. This protective hood serves to ensure that the nozzle is not directly exposed to the combustion gases or the dust particles, in particular the cement dust particles.

materials

In a further particularly preferred embodiment, the cladding tube is made of a highly heat-resistant, heat-resistant and scaling-resistant, sintered, oxide-dispersion-strengthened metallic material, i.e. from a steel or a superalloy.

In a further preferred embodiment, at least one outer, highly wear-resistant coating is applied to the cladding tube by means of build-up welding.

The oxide dispersion strengthened (ODS: oxide dispersion strengthened) steel or such an alloy consists of a mixture of a powder of a high-temperature, heat-resistant alloy and a very finely ground powder of a high-melting ceramic, preferably yttrium oxide (Y ₂ O ₃ ), zirconium oxide ( ZrO ₂ ) or hafnium oxide (HfO ₂ ), particularly preferably yttrium oxide (Y ₂ O ₃ ). These oxide-dispersion-strengthened materials therefore essentially consist of metallic base materials in which highly stable or inert oxides are embedded in finely distributed form. These inert particles do not change up to the melting point of the metallic matrix and are also insoluble in the melt. The high-melting oxide prevents dislocations from migrating in the metallic material and therefore contributes to the high creep resistance, especially at high temperatures, for example of gases above 1,000 ° C up to 1,250 ° C.

Both components - the powder of a high-temperature, heat-resistant alloy and the very finely ground powder from a high-melting ceramic - are intimately mixed with one another during the manufacturing process, pressed and sintered at high temperatures, but without melting. The result is a material with a sufficiently high strength at very high temperatures.

The highly heat-resistant, heat-resistant and scaling-resistant sintered metallic material is an oxide-dispersion-strengthened steel or an oxide-dispersion-strengthened superalloy. A suitable and preferred oxide dispersion strengthened steel contains 70.0 to 80.0% by weight Fe, 0.0 to 10.0% by weight Al, 10.0 to 25.0% by weight Cr, 0, 0 to 1.0% by weight of Ti and 0.05 to 1.5% by weight of oxides of one or more elements selected from the group consisting of Y, Zr, Hf, preferably Y.

In a further preferred embodiment, the highly heat-resistant, heat-resistant and scaling-resistant, sintered, oxide-dispersion-strengthened superalloy contains 65.0 to 80.0% by weight Ni, 10.0 to 20.0% by weight Cr, 0.5 to 10.0% by weight Al, up to 0.1% by weight C, up to 0.5% by weight Ti and up to 1.5% by weight oxides of one or more elements selected from the group Y, Zr, Hf, preferably Y.

In a further preferred embodiment, the high temperature, heat and scale resistant, sintered, oxide dispersion strengthened superalloy contains 55.0 to 70.0 wt.% Ni, 18.0 to 25.0 wt.% Cr, 6.0 to 12.0% by weight Mo, 3.0 to 6.0% by weight Fe, 2.5 to 4.5% by weight Nb / Cb, up to 0.1% by weight C, up to 0, 5 wt% Al, up to 0.5 wt% Ti and up to 1.5 wt% oxides of one or more elements selected from the group Y, Zr, Hf, preferably Y.

• PM 3000 (Nominale chemische Zusammensetzung in Gewichts-%): 67,0 Ni, 20,0 Cr, 6,0 Al, 3,5 W, 2,0 Mo, 0,15 Zr, 0,01 B, 0,05 C, 1,1 Y₂O₃;
• FeCrAlMo-Legierung (chemische Zusammensetzung in Gewichts-%): 20,5 bis 23,5 Cr, 5,0 Al, 3,0 Mo, 0,0 bis 0,7 Si, 0,0 bis 0,4 Mn, 0,0 bis 0,08 C, 0,5 bis 1,5 Y₂O₃, Rest Fe, insbesondere: 21,0 Cr, 5,0 Al, 3,0 Mo, 0,5 Y₂O₃, Rest Fe;
• Legierung (chemische Zusammensetzung in Gewichts-%): 58,0 Gew.-% Ni, 20,0 bis 23,0 Gew.-% Cr, 8,0 bis 10,0 Gew.-% Mo, 5,0 Gew.-% Fe, 3,15 bis 4,15 Gew.-% Nb/Cb, bis 0,5 Gew.-% Cu, bis 0,1 Gew.-% C, bis 0,4 Gew.-% Al, bis 0,4 Gew.-% Ti, bis 0,5 Si, bis 0,5 Mn, und 0,5 bis bis 1,5 Gew.-% Oxide eines oder mehrerer Elemente ausgewählt aus der Gruppe Y, Zr, Hf, bevorzugt Y.

Particularly suitable and preferred metallic materials are the following materials with the chemical composition mentioned:

• PM 3000 (nominal chemical composition in% by weight): 67.0 Ni, 20.0 Cr, 6.0 Al, 3.5 W, 2.0 Mo, 0.15 Zr, 0.01 B, 0.05 C, 1.1 Y ₂ O ₃ ;
• FeCrAlMo alloy (chemical composition in% by weight): 20.5 to 23.5 Cr, 5.0 Al, 3.0 Mo, 0.0 to 0.7 Si, 0.0 to 0.4 Mn, 0 , 0 to 0.08 C, 0.5 to 1.5 Y ₂ O ₃ , remainder Fe, in particular: 21.0 Cr, 5.0 Al, 3.0 Mo, 0.5 Y ₂ O ₃ , remainder Fe ;
• Alloy (chemical composition in% by weight): 58.0% by weight Ni, 20.0 to 23.0% by weight Cr, 8.0 to 10.0% by weight Mo, 5.0% by weight -% Fe, 3.15 to 4.15% by weight Nb / Cb, up to 0.5% by weight Cu, up to 0.1% by weight C, up to 0.4% by weight Al, up to 0.4 wt.% Ti, up to 0.5 Si, up to 0.5 Mn, and 0.5 to 1.5 wt.% Oxides of one or more elements selected from the group Y, Zr, Hf, are preferred Y.

The lance system according to the present invention is also preferably designed to be highly resistant to erosion. This is achieved by an outer coating. In a preferred embodiment of the lance system, the outer, highly wear-resistant coating which is applied to the cladding tube comprises (i) hard particles, the hard particles comprising at least one of carbides, nitrides, borides, silicides and oxides and solid solutions thereof, and (ii ) a binding agent that binds the hard particles together. The hard particles can comprise at least one transition metal carbide selected from carbides of titanium, chromium, zirconium, hafnium, tantalum, molybdenum, niobium and tungsten or solid solutions thereof. The hard particles can be present as single or mixed carbides and / or as sintered cemented carbides.

In a further preferred embodiment of the lance system, the outer, highly wear-resistant coating, which is applied to the cladding tube, has hard particles containing one or more transition metal carbides or solid solutions thereof and a binder selected from the group consisting of cobalt, nickel, iron and a Heat-resistant alloy of iron, chromium and nickel with a proportion of cobalt. The hard particles preferably contain carbides of titanium, chromium, zirconium, hafnium, tantalum, molybdenum, niobium and tungsten or solid solutions thereof, the binder being selected from the group consisting of cobalt, nickel, iron, preferably cobalt, and a heat-resistant alloy Iron, chromium and nickel with a proportion of cobalt.

The carbides are more preferably tungsten carbide and optionally molybdenum carbide or solid solutions thereof, and the binder is cobalt or a heat-resistant alloy of iron, chromium and nickel with a proportion of cobalt. A particularly suitable and preferred highly wear-resistant coating or armouring contains or consists of tungsten carbide and optionally molybdenum carbide in a binder or a matrix essentially consisting of cobalt or a heat-resistant alloy of iron, chromium and nickel with a proportion of cobalt.

In a further preferred embodiment, the coating comprises 40.0 to 50.0% by weight of tungsten carbide and 40.0 to 60.0% by weight of at least one of iron, cobalt and nickel, particularly preferably cobalt or a heat-resistant alloy of iron , Chrome and nickel with a proportion of cobalt.

The outer, highly wear-resistant coating or armoring is applied by surfacing and preferably has a thickness of at least 2.0 mm, more preferably 2.0 to 10.0 mm, and even more preferably a thickness of 2.0 to 3.5 mm on.

The highly heat-resistant, heat-resistant and scaling-resistant, sintered, oxide-dispersion-strengthened metallic material has very good properties for the construction of a cantilevered lance that protrudes into rooms through which hot gases flow. The cladding tube of the lance system made from this metallic material represents thus the required strength properties and ensures that the self-supporting lance does not permanently bend or even tear off even with a length of, for example, 5 m in the course of time due to its own weight and the attacking flow forces. In normal operation, this cladding tube is cooled by the enveloping air flowing continuously inside and does not even come close to the temperature of the surrounding flue gas. However, if this cooling enveloping air fails, e.g. if the associated fan fails or while the injection lance is pulled out of the enveloping tube for maintenance purposes or is then pushed back into it, the enveloping tube is at the original flue gas temperature at the point where the lance system injects reagents from, for example 850 to 1,000 ° C for a period of at least a few days and is therefore not damaged.

The present invention further provides a reaction space which is designed to have combustion gases flowing through it, the reaction space containing at least one lance system as described above according to the invention. The inner section of the lance system is arranged inside the reaction space and the outer section of the lance system is arranged outside the reaction space. With the device according to the invention, reaction spaces such as calciners, flue gas ducts or boilers or fireplaces, some of which have large cross-sections, can be acted upon with appropriate reagents over the entire cross-section. With the device according to the invention, the reagents required to reduce pollutants can now also reach the central areas of the cross-section of these reaction chambers, as well as being injected into combustion gases that are dust-laden and, in some cases, flowing at high speeds and have a temperature of about 1,000 ° C.

In particular, it is advantageous that reaction spaces can now be equipped with lance systems that can be quickly and easily dismantled and dismantled and reassembled and reassembled, thus enabling faster and easier maintenance and cleaning of the individual parts (injection lance and cladding tube). Furthermore, preferred measures ensure that the nozzles are protected from caking.

In a preferred embodiment of the reaction space, the lance system projects self-supporting into the interior of the reaction space, this self-supporting section of the lance system projecting into the interior of the reaction space preferably having a length of 15% to 50%, preferably 20% to 40% of the diameter of the interior of the reaction chamber. The interior of the reaction space is defined as the inner free space of the reaction space, i.e. within any linings on the inner wall of the reaction space.

In a further preferred embodiment of the reaction space, the lance system projects self-supporting into the interior of the reaction space, this self-supporting section of the lance system projecting into the interior of the reaction space preferably having a length of at least 0.5 m, preferably a length of at least 1.0 m, more preferably a length of at least 2.0 m, even more preferably a length of at least 3.0 m, and particularly preferably a length of at least 4.0 m. It is also preferred that a length of 5.0 m is not exceeded.

In a further preferred embodiment, the reaction space is a calciner of a cement works, which is designed to allow the combustion gas, which is fed directly or indirectly from a rotary kiln, to flow through the calciner and to convey raw meal in the opposite direction through the calciner for calcination in the direction of the rotary kiln. The cement clinker is then produced in the rotary kiln.

The lance systems can be arranged horizontally or vertically in the boiler depending on the type of calciner or calcining reactor. The lances are preferably arranged horizontally since the flow through the calciner is usually perpendicular.

The reagent or the reducing agent for NO _x is introduced via the injection lance and reaches the reaction chamber via the nozzles of the injection lance. Farther enveloping air is also supplied via the lance system in that it is passed directly into the enveloping tube, ie into the space between the injection lance and the enveloping tube. The reagent or the reducing agent is injected from the nozzle through the outlet opening (internal opening) in the end plate of the cladding tube directly into the combustion gas flow, the reducing agent also being surrounded by enveloping air, which is drawn from the space between the injection lance and the cladding tube through the inside opening of the closing plate and flows into the combustion gas stream through the gap between the edge of the end plate and the inside of the cladding tube.

In a preferred embodiment, the calciner or calcining reactor has at least one separate fuel supply and at least one separate combustion air supply.

In a preferred alternative embodiment, the reaction space is a boiler or a furnace, in particular of power plants and systems for steam generation and waste incineration systems, which furthermore contains at least one supply for fuel and at least one supply for combustion air. As a boiler or combustion chamber, the boiler contains, in addition to at least one feed for fuel, at least one feed for combustion air according to the invention, at least one of the lance systems described above; wherein the inner portion of the lance system is arranged inside the vessel and the outer portion of the lance system is arranged outside the vessel. The inner section of the at least one lance system protrudes into the interior of the vessel in a self-supporting manner and preferably has a length of 15% to 50%, preferably 20% to 40% of the diameter of the interior of the reaction space. It is also preferred that the inner section of the at least one lance system protrudes into the interior of the tank in a self-supporting manner and preferably has a length of at least 0.5 m, preferably a length of at least 1.0 m, more preferably a length of at least 2.0 m , even more preferably has a length of at least 3.0 m, and particularly preferably a length of at least 4.0 m. It is also preferred that a length of 5.0 m is not exceeded.

In the boiler or combustion chamber, fuel and combustion air are brought together to carry out the combustion. The resulting flue gas or combustion gas flows through the furnace and then through the subsequent heating surfaces located in the flue gas flow. In the area of the heating surfaces, below, in between or above, one or more lance systems according to the invention are arranged, which supply the nitrogen oxide reducing agent.

The feed for the reagent or the reducing agent and the feed for the introduction of the air (enveloping air) into the space between the injection lance and the enveloping tube are advantageously arranged outside the reaction space (calciner, boiler, furnace, flue gas duct). Furthermore, a supply for a propellant (compressed air) is preferably arranged in order to atomize the reagent or the reducing agent at the nozzle.

The arrangement of the lance system according to the invention in the reaction space depends on the prevailing temperatures of the combustion gas in which the nitrogen oxide is to be reduced. The optimum temperature for the conversion of NO _x according to the selective non-catalytic process is in the range from 850 ° C to 1,000 ° C.

The alignment of the lance systems in the reaction space can be horizontal or vertical. In the preferred configurations of the reaction space according to the invention, one or more lance systems according to the invention can be arranged. A plurality of lance systems are particularly preferably arranged distributed uniformly over the inner cross-section of the reaction space so that each area of the combustion gas flow is reached with the reagent or reducing agent. By arranging several lances, a uniform distribution of the reagent or reducing agent is achieved. The lance systems can also be arranged one above the other in one or more horizontal planes, in particular when the lance systems are aligned horizontally.

In a particularly preferred embodiment of the reaction space, several lance systems are arranged parallel to one another.

As already explained above, the lance systems can be arranged horizontally or vertically in the reaction space. With a horizontal arrangement of the lance system, the nozzle, which is inclined to the longitudinal axis of the cladding tube as described above, is aligned in the flow direction of the combustion gas flow.

In a further embodiment of the reaction chamber, a lateral enveloping air supply connection is also arranged in order to be able to blow the intermediate gap between the enveloping tube and the wall of the reaction chamber by means of the enveloping air, and in this way to prevent the cladding tube from sticking due to penetrated dust if the dew point is possibly below the dew point avoid.

The technical problem is also achieved by a method for injecting reagents in the form of fluids into combustion gases within a reaction space through which these combustion gases flow, the reagents being injected into combustion gases as described above by means of at least one lance system, which flow through the reaction space.

• über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte des Hüllrohrs;
• über den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs;
• über ggf. weitere vorhandene Durchgangslöcher in der Abschlussplatte.

In a preferred method, enveloping air is fed into the space in the lance system, which is formed between the outer wall of the injection lance and the inner wall of the enveloping tube, and from there is introduced into the combustion gas at least via the following outlet openings:

• across the gap between the nozzle of the injection lance and the edge of the inner opening of the end plate of the cladding tube;
• across the gap between the edge of the end plate and the inner wall of the cladding tube;
• via any additional through holes in the end plate.

1. a) Reagenzien in Form eines fluiden Gemisches enthaltend Reduktionsmittel durch ein in der Eindüslanze verlaufendes Flüssigreagenz-Zuführrohr zugeführt und von dort über die Düse direkt durch die innenliegende Öffnung der Abdeckplatte des Hüllrohrs hindurch in das Verbrennungsgas geleitet;
2. b) Hüllluft in den Zwischenraum zwischen der Eindüslanze und der inneren Wand des Hüllrohrs getrennt zugeführt;
3. c) ein Teil der Hüllluft aus b) über den Spalt zwischen der Düse der Eindüslanze und dem Rand der innenliegenden Öffnung der Abschlussplatte aus dem Hüllrohr austreten lassen, wodurch ein innerer Hüllluftschleier gebildet wird; und
4. d) ein anderer Teil der Hüllluft aus b) durch den Spalt zwischen dem Rand der Abschlussplatte und der Innenwand des Hüllrohrs aus dem Hüllrohr austreten lassen und in das Verbrennungsgas geleitet, wodurch ein äußerer Hüllluftschleier gebildet wird.

In a further preferred method:

1. a) reagents in the form of a fluid mixture containing reducing agents are supplied through a liquid reagent supply pipe running in the injection lance and passed from there via the nozzle directly through the inner opening of the cover plate of the cladding tube into the combustion gas;
2. b) enveloping air is supplied separately into the space between the injection lance and the inner wall of the enveloping tube;
3. c) let some of the enveloping air from b) exit the enveloping tube via the gap between the nozzle of the injection lance and the edge of the inner opening of the closing plate, whereby an inner enveloping air curtain is formed; and
4. d) let another part of the enveloping air from b) emerge from the enveloping tube through the gap between the edge of the end plate and the inner wall of the enveloping tube and pass it into the combustion gas, whereby an outer enveloping air curtain is formed.

With the method according to the invention, reaction spaces, such as calciners, flue gas ducts or boilers or fireplaces, some of which have large cross-sections, can be acted upon with appropriate reagents over the entire cross-section. This means that with the method according to the invention, the reagents required to reduce pollutants can also reach the central areas of the cross-section of these reaction spaces and these reagents can also be injected into dust-laden combustion gases, some of which are flowing at high speeds and have a temperature of around 1,000 ° C. With the lance construction according to the invention and the special alignment of the nozzle to the longitudinal axis of the cladding tube, easier installation and removal of the injection lance is now made possible, the cladding tube remaining in place in the reaction space. In this way, maintenance work and repairs are made much easier.

The further preferred measures, especially in the nozzle area, reduce the likelihood of caking in the nozzle area, so that maintenance and cleaning intervals can be extended. Thus, two concentric enveloping air ring gaps are preferably provided around the nozzle. The outer gap runs around the inclined end plate without interruption and flushes the gap between the outer area of this plate and the inner area of the lance tube. Another inner air curtain created by the gap directly surrounding the nozzle prevents cement dust from reaching the nozzle itself and its liquid droplets.

Enveloping air can be passed from the cladding tube into the combustion gas via further through holes of the cladding tube, which are preferably arranged in the end plate, and the inclined end plate can thereby be kept free of cement dust.

A method is particularly preferred in which the combustion gases use the lance system (s) with a dust load of 1 g / Nm ³ up to 1000 g / Nm ³ at a volume flow of 10,000 to 2,000,000 m ³ / h, preferably 30 g / Nm ³ up to 1000 g / Nm ³ with a volume flow of 10,000 to 2,000,000 m ³ / h, more preferably from 100 g / Nm ³ to 1000 g / Nm ³ with a volume flow of 10,000 to 2,000,000 m ³ / flow around h.

In a further preferred method, the combustion gases flow around the lance system at a temperature in the range from 850 ° C to 1,000 ° C.

In particular, a method is preferred in which the injected reagent is a reducing agent for reducing the concentration of nitrogen oxides in the combustion gas.

In a further preferred method, the reducing agent is injected into the combustion gas within a calciner or calcining reactor of a cement works, which is passed directly or indirectly from a rotary kiln and flows through the calciner, with raw meal being conveyed in the opposite direction through the calciner for calcination in the direction of the rotary kiln will. The cement clinker is then produced in the rotary kiln.

In a further preferred method, further combustion gas is produced in the calciner by burning a fuel.

1. a) Erzeugen eines Verbrennungsgases in einer Verbrennungszone wobei das Verbrennungsgas Stickoxide enthält;
2. b) Injizieren eines selektiven Reduktionsmittels in den Verbrennungsgasstrom innerhalb des Reaktionsraumes stromabwärts der Verbrennungszone gemäß a);
3. c) Reaktion des Reduktionsmittels mit den Stickoxiden unter Bildung von N₂ und H₂O.

Another preferred method for reducing the concentration of nitrogen oxides in a combustion gas includes the following steps:

1. a) generating a combustion gas in a combustion zone, the combustion gas containing nitrogen oxides;
2. b) injecting a selective reducing agent into the combustion gas stream within the reaction space downstream of the combustion zone according to a);
3. c) Reaction of the reducing agent with the nitrogen oxides with the formation of N ₂ and H ₂ O.

According to the invention, the reducing agent is introduced into the reaction space via one or more lance systems, preferably in a calciner or calcining reactor of a cement plant, in a boiler or furnace of a power plant or a system for generating steam, or in a flue gas duct, the reducing agent in via the injection lance of the respective lance system is fed, then the reducing agent is fed out of the injection lance via the nozzle directly through the inner opening of the end plate of the cladding tube to the outside. Preferably, compressed air for atomizing the reducing agent is fed separately into the nozzle via the injection lance. In addition, air is fed into the space between the injection lance and the cladding tube (enveloping air), with the enveloping air emerging from the cladding tube through the opening (or through the gap directly surrounding the nozzle) and through the gap between the end plate and the cladding tube and the Injected reactant surrounds and finally meets the combustion gases in the reaction chamber.

A nitrogen-containing compound is used as the reducing agent for reducing nitrogen oxides, selected from the group consisting of urea, ammonia, cyanuric acid, hydrazine, ethanolamine, biuret, triuret, ammelide, ammonium salts of organic and inorganic acids (for example ammonium acetate, ammonium sulfate, ammonium bisulfate, ammonium bisulfite, Ammonium formate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium oxalate), preferably urea or ammonia. The reducing agent is preferably fed in an aqueous solution (e.g. ammonia water, or urea dissolved in water) or in gaseous form (ammonia) into the lance system, in particular into the injection lance, preferably into the liquid reagent feed pipe.

In a preferred method, the reducing agent is mixed on or in the nozzle of the injection lance with separately supplied compressed air for atomization.

In a preferred embodiment of the method, the reagent or the reducing agent meets combustion gas with a temperature in the range from 850 ° C. to 1,000 ° C. when it emerges from the jacket tube of the lance system.

The invention is described in more detail with reference to the figures.

characters

• Figure 1 shows a schematic longitudinal section through the lance system according to the invention.
• Figure 2 shows a detailed area of the nozzle and the end plate in longitudinal section.
• Figure 3 shows a view of the end plate.
• Figure 4 shows a longitudinal section through the end of the lance system with a partial view of the end plate.

the Figure 1 shows a schematic longitudinal section through the lance system 1 according to the invention. The lance system is used to introduce reagents into reaction spaces 2 through which combustion gases 3 flow, such as calciners in cement works. The lance system 1 shown in the figure comprises a cladding tube 6 which contains an injection lance 7 with a nozzle 8 on the inside. The injection lance 7 has a feed pipe for a liquid reagent 19 and a feed pipe for compressed air 18. In the embodiment shown, the liquid reagent supply pipe 19 lies within the compressed air supply pipe 18.

At its distal end protruding into the reaction space 2, the cladding tube 6 has an end plate 9 which delimits the interior of the cladding tube 6 towards the outside. The end plate 9 has an internal opening into which the nozzle 8 of the injection lance 7 is inserted in such a way that a circumferential gap 11 remains between the nozzle 8 and the edge of the internal opening of the end plate 9.

According to the invention, the plane of the end plate 9 is inclined to the longitudinal axis of the cladding tube 6 so that the injection lance 7 with the nozzle 8 can be pulled out of the cladding tube 6 without the likewise inclined nozzle 8 getting stuck in the opening of the end plate 9. As a result, it is now possible to pull the injection lance 7 out of the cladding tube 6 for cleaning and maintenance, which remains in place in the reaction space 2. So both parts can be serviced and cleaned. In the figure, an embodiment is shown, wherein the longitudinal axis of the nozzle 8 is inclined at an angle of 45 ° to the longitudinal axis of the cladding tube and the plane of the end plate 9 is also inclined at an angle of 45 ° to the longitudinal axis of the cladding tube. As a result, the longitudinal axis of the nozzle 8 comes to lie at an angle of 90 ° to the plane of the end plate 9.

Furthermore, the construction according to the invention allows the nozzle 8 or the nozzle head to protrude a little, for example 6 to 8 mm, beyond the end plate 9 in the direction of the reaction chamber 2, which is the case with a 90 ° deflection of the nozzle 8 to the longitudinal axis of the Cladding tube 6 would not be possible. This offers the advantage that the risk of caking due to liquid droplets spraying directly from the nozzle onto the surrounding protective hood 22 is greatly reduced.

In the embodiment shown, a completely circumferential or uninterrupted gap 12 is also provided between the edge of the end plate 9 and the inner wall of the cladding tube 6. The end plate 9 is attached to the cladding tube 6 with the aid of fastenings 10 attached inside the cladding tube 6. These fastenings 10 are attached to the inside of the end plate 9 and in particular at a distance from the edge of the end plate 9 as well as on the inside of the cladding tube that a completely circumferential or uninterrupted gap 12 remains between the edge of the end plate 9 and the inner wall of the cladding tube 6 , through which the enveloping air can flow to the outside without hindrance.

The lance system 1 shown in the figure has two concentric enveloping air ring gaps around the nozzle 8. As explained above, the outer gap 12 runs without interruption around the edge of the inclined end plate 9. The Enveloping air exiting through this gap 12 clears the gap between the outer area of the end plate 9 and the inner area of the cladding tube 6. In addition to this outer enveloping air curtain, there is a further inner enveloping air curtain which is generated by the gap 11 which directly surrounds the nozzle 8. The two enveloping air curtains prevent cement dust from reaching the nozzle 8 itself and its liquid droplets. The figure shows one of several further through holes 13 in the end plate 9, which serve to keep the inclined end plate 9 free of cement dust with the air flowing out of the jacket tube 6. These additional through holes 13 or enveloping air holes are arranged around the inner opening 11 of the end plate 9, ie around the gap between the nozzle 8 and thus also around the edge of the inner opening of the end plate 9.

The figure also shows guide lugs 14 which are attached to the injection lance 7 and rails 15 which are beveled in the manner of a ramp and which are arranged on the inner wall of the cladding tube 6. When the injection lance 7 is pushed into the cladding tube 6, the guide lugs 14 engage in the rails 15, so that the injection lance 7 is correctly aligned and detachably fixed within the cladding tube 6. The guide lugs 14 and ramp-like beveled rails 15 are constructed and arranged in such a way that when the injection lance 7 is pushed in, the nozzle 8 comes to rest in the opening of the end plate 9 so that a gap 11 remains around the nozzle 8 and the axis of the nozzle 8 is essentially perpendicular to the plane of the end plate 9.

The one in the Figure 1 The embodiment shown of the lance system 1 has an inner section 4, which is arranged inside the reaction space 2, and an outer section 5, which is arranged outside the reaction space. As already explained, the injection lance 7 is inserted through the outer end of the cladding tube 6 arranged in the outer section 5 into the cladding tube 6 and fastened by means of a quick-release coupling 21. The quick release coupling 21 is used to be able to install and remove the injection lance 7 easily and quickly.

According to the Figure 1 The embodiment shown is in the outer section 5, the supply for enveloping air 17, the enveloping air in the space 16 between the injection lance 7 and the cladding tube 6, the supply for compressed air 23 and the supply for the liquid reagent 24 are arranged.

Figure 2 shows a detailed area of the nozzle 8 and the end plate 9 in longitudinal section. As explained above, the end of the cladding tube 6 which projects into the reaction space has an end plate 9. This delimits the interior 16 of the cladding tube 6 to the outside. An internal opening is arranged in the middle area of the end plate 9. The nozzle 8 of the injection lance 7 is inserted into this opening in such a way that a complete circumferential gap 11 remains between the nozzle 8 and the edge of the inner opening of the closing plate 9. Enveloping air passes through this gap 11 from the interior 16 of the cladding tube into the reaction space. In this way, an enveloping air curtain is generated which (completely) encloses the nozzle 8 and the fluid injected by this nozzle.

The detailed view shows that the plane of the end plate 9 is inclined to the longitudinal axis of the cladding tube 6. In addition, the longitudinal axis of the nozzle 8 is inclined at an angle of 45 ° to the longitudinal axis of the cladding tube 6 in the direction of the end plate 9. The design allows the injection lance 7 with the nozzle 8 to be pulled out of the cladding tube 6 without the nozzle 8 getting stuck in the opening of the end plate 9. In this way, the injection lance 7 for cleaning and maintenance of the same, as well as the cladding tube 6, can be pulled out of the cladding tube, the cladding tube 6 remaining in place, protruding into the reaction space.

The view also shows the possibility that the nozzle 8 or the nozzle head can protrude somewhat beyond the closing plate 9 in the direction of the reaction space 2. This would not be possible with a lance with a 90 ° deflection of the nozzle head 8 in relation to the longitudinal direction of the cladding tube 6.

The figure also shows the gap 12 which is provided between the edge of the end plate 9 and the inner wall of the cladding tube 6 all around the end plate 9. As already explained above, the end plate 9 is fastened to the inside of the cladding tube 6 with fastenings 10. The fastenings 10 are on the one hand on the inside of the end plate 9 at a distance from the edge of the end plate 9 and attached to the inside of the cladding tube, so that a completely circumferential or uninterrupted gap 12 remains between the edge of the end plate 9 and the inner wall of the cladding tube 6, through which the enveloping air can flow to the outside without hindrance.

The figure also shows one of several further through holes 13 in the end plate 9. These through holes 13 serve to keep the inclined end plate 9 and the nozzle 8 and surrounding areas free of cement dust with the aid of the enveloping air flowing out of the cladding tube 6. These additional through holes 13 or enveloping air holes are arranged around the inner opening of the end plate 9, i.e. around the gap between the nozzle 8 and thus also around the edge of the inner opening of the end plate 9.

the Figures 3 and 4 show a view of the end plate 9. Figure 4 shows the same view as a longitudinal section. The end of the cladding tube 6 protruding into the reaction space has, as explained above, an end plate 9 which delimits the interior 16 of the cladding tube 6 towards the outside. An internal opening is arranged in the middle area of the end plate 9. The nozzle 8 of the injection lance 7 is inserted into this opening in such a way that a complete circumferential gap 11 remains between the nozzle and the edge of the inner opening of the closing plate 9.

In addition, a gap 12 is arranged which runs completely around the end plate 9 between the edge of the end plate 9 and the inner wall of the cladding tube 6. In the embodiment shown, five through holes 13 are also provided in the end plate 9, which are arranged around the inner opening of the end plate 9 and thus around the nozzle 8. At the end of the lance system, a protective hood 22 is designed as an extension of the cladding tube 6, which is arranged on the side from which the flow of combustion gases or the flow of cement dust particles comes. This protective hood 22 serves to ensure that the nozzle 8 and surrounding areas are not directly exposed to the combustion gases or the cement dust particles.

In addition, in Figure 3 the course of the injection lance 7 and the arrangement of the guide nose 14 and the rail 15 are indicated.

In the Figure 4 the guide inside the cladding tube 6 is also shown in longitudinal section in order to correctly position the end of the injection lance 7 and in particular the nozzle 8 so that the nozzle 8 comes to rest in the inner opening of the end plate 9 and a gap 11 around the nozzle 8 remains.

The figure shows one of the guide lugs 14 arranged on the injection lance 7, which when the injection lance 7 is pushed into the cladding tube 6 into the rail 15 (see also FIG Figures 1 and 3 ) intervenes. In addition, further ramp-like beveled rails 15 at the end of the cladding tube 6 are shown in the figure, which serve for the exact positioning of the nozzle 8. For this purpose, corresponding guide lugs 14 or spacers 14 are also arranged in the area of the nozzle 8, which, when installed, are in contact with the ramp-like beveled rails. The rails 15, guide lugs 14 and spacers 14 are constructed and arranged in such a way that when the injection lance 7 is pushed in, the nozzle 8 comes to rest in the opening of the end plate 9 in such a way that a gap 11 remains around the nozzle 8 and the axis of the The nozzle 8 is essentially perpendicular to the plane of the end plate 9.

List of reference symbols

1

Lance system

2

Reaction space (calciner, boiler / furnace, flue gas duct)

3rd

Combustion gas

4th

inner section of the lance system

5

outer section of the lance system

6th

Cladding tube

7th

Injection lance

8th

jet

9

End plate

10

Attachment for the end plate

11

circumferential gap around nozzle

12th

Gap between the edge of the end plate and the inner wall of the cladding tube

13th

Through hole

14th

Guide nose

15th

rail

16

Space between cladding tube and injection lance

17th

Supply for enveloping air

18th

Supply pipe for compressed air

19th

Feed tube for liquid reagent (reducing agent or absorbent)

20th

Wall of the reaction space

21

Quick release coupling

22nd

Protective hood

23

Supply for compressed air

24

Feed for liquid reagent (reducing agent or absorbent)

Claims (14)

1. A lance system (1) for introducing reagents by means of a nozzle (8) into reaction spaces (2) through which combustion gases (3) flow, the lance system (1) comprising:

   - a sheath tube (6) which is configured to be arranged at least partially within the reaction space (2);

   - an injection lance with a supply tube for a liquid reagent, optionally a supply tube for compressed air, and with the nozzle for injecting the reagent, wherein the injection lance can be inserted into the sheath tube;

   characterized in that
   the sheath tube (6) has an end plate (9) at its distal end which delimits the interior of the sheath tube (6) towards the outside, the end plate (9) having an internal opening for the arrangement of the nozzle (8) and the plane of the end plate (9) of the sheath tube (6) is arranged at an angle of 25 to 65° to the longitudinal axis of the sheath tube,
   the longitudinal axis of the nozzle (8) of the injection lance (7) in the installed state has an angle of 25 to 65° to the longitudinal axis of the sheath tube (6) and is inclined towards the end plate (9); and
   the nozzle (8) of the injection lance (7) is arranged and aligned in relation to the inner opening of the end plate (9) so that the nozzle (8) can inject the reagent through the inner opening of the end plate (9).
2. The lance system (1) according to claim 1, characterized in that in the installed state the nozzle (8) of the injection lance (7) protrudes at least partially through the internal opening of the end plate (9).
3. The lance system (1) according to claim 1 or 2, characterized in that in the installed state a completely circumferential or uninterrupted gap (11) is provided between the nozzle (8) of the injection lance (7) and the edge of the inner opening of the end plate (9).
4. The lance system (1) according to any one of claims 1 to 3, characterized in that the end plate (9) of the sheath tube (6) is dimensioned such that a completely circumferential or uninterrupted gap (12) is provided between the edge of the end plate (9) and the inner wall of the sheath tube (6).
5. The lance system (1) according to any one of claims 1 to 4, characterized in that the end plate (9) of the sheath tube (6) has further through holes (13).
6. The lance system (1) according to any one of claims 1 to 5, characterized in that the lance system (1) has an intermediate space (16) which is formed between the outer wall of the injection lance (7) and the inner wall of the sheath tube (6), the intermediate space (16) being in fluid communication with the outside via at least the following outlet openings:

   - via the gap (11) between the nozzle (8) of the injection lance (7) and the edge of the inner opening of the closing plate (9) of the sheath tube (6);

   - via the gap (12) between the edge of the end plate (6) and the inner wall of the sheath tube (6);

   - via optional through holes (13) additionally provided in the end plate.
7. The lance system (1) according to any one of claims 1 to 6, which is constructed in such a way that the injection lance (7) can be inserted into the sheath tube (6) and aligned and releasably fixed within the sheath tube (6) by means of rails (15) which are bevelled in ramp-like fashion and are arranged on the inner wall of the sheath tube (6), into which rails (15) guide lugs (14) engage which are arranged on the side of the injection lance (7), or
   the injection lance (7) can be inserted into the sheath tube (6) and aligned and releasably fixed within the sheath tube by means of guide lugs (14) arranged on the inner wall of the sheath tube (6) which engage in rails (15) which are bevelled in ramp-like manner and are arranged on the side of the injection lance (7).
8. The lance system (1) according to any one of claims 1 to 7, characterized in that the injection lance (7) has a liquid reagent supply tube (19) and a compressed air supply tube (18), wherein the liquid reagent supply tube (19) preferably runs within the compressed air supply tube (18).
9. The lance system (1) according to any one of claims 5 to 8, characterized in that the lance system (1) is constructed,

   a) to supply reagents in the form of a fluid mixture containing reducing agents through a liquid reagent supply tube (19) running within the injection lance (7) and from there to pass them via the nozzle (8) directly through the inner opening of the cover plate (9) of the sheath tube (6) to the outside;

   b) supplying enveloping air separately into the intermediate space (16) between the injection lance (7) and the inner wall of the sheath tube (6);

   c) to allow a part of the enveloping air from b) to exit the sheath tube (6) through the gap (11) between the nozzle (8) of the injection lance (7) and the edge of the inner opening of the end plate (9), whereby an inner enveloping air curtain is formed; and

   d) to allow another part of the enveloping air from b) to exit the sheath tube (6) through the gap (12) between the edge of the end plate (9) and the inner wall of the sheath tube (6), whereby an outer enveloping air curtain is formed.
10. The lance system (1) according to any one of claims 1 to 9, characterized in that the lance system (1) has an inner section (4) designed to be arranged within the reaction space (2), and an outer section (5) designed to be arranged outside the reaction chamber (2), a quick release coupling (21) being provided to insert the injection lance (7) through the opening of the sheath tube (6) arranged in the outer section (5) into the sheath tube (6) and fasten it using the quick release coupling (21).
11. A reaction space (2) which is designed to be flowed through by combustion gases, characterized in that the reaction space (2) contains at least one lance system (1) according to any one of claims 1 to 10.
12. The reaction space (2) according to claim 11, characterized in that the lance system (1) projects self-supporting into the interior of the reaction space (2) and this self-supporting section of the lance system (1) projecting into the interior of the reaction space (2) preferably has a length of has at least 15% to 50% of the diameter of the interior of the reaction space.
13. A method for injecting reagents in the form of fluids into combustion gases (3) within a reaction space (2) through which these combustion gases (3) flow, characterized in that the reagents are injected by means of at least one lance system (1) according to any one of claims 1 to 10 into combustion gases (3), which flow through the reaction chamber (2).
14. The method according to claim 13, characterized in that the combustion gases (3) surround the lance system(s) (1) with a dust load of 1 g/Nm³ up to 1000 g/Nm³ at a volume flow of 10,000 to 2,000,000 m³/h, preferably from 30 g/Nm³ to 1000 g/Nm³ with a volume flow of 10,000 to 2,000,000 m³/h, more preferably from 100 g/Nm³ to 1000 g/Nm³ with a volume flow of 10,000 to 2,000,000 m³/h.

Images